SK4692000A3 - Layered absorbent structure with a zoned basis weight - Google Patents

Abstract

A distinctive absorbent article includes an absorbent core having multiple absorbent layers, wherein the absorbent layers interact in such a manner which preferentially locates absorbed liquid in an appointed, high saturation wicking layer. The localization of the liquid within this wicking layer increases the potential of this layer to move liquid through capillary action due to the higher saturation level and increased amount of liquid available. In additional aspects, at least one primary layer region can have a non-uniform, selectively zoned basis weight distribution. Particular configurations of the at least one primary layer region can be constructed with a target area of the primary layer region having a basis weight which is less than a basis weight of another non-target portion of the primary layer region.

Description

BASIC WEIGHT

Technical field

The present invention generally relates to a layered absorbent structure. Specifically, the present invention relates to a layered composite absorbent structure provided with specific layers that are designed and arranged to interact selectively with each other to provide the composite layered absorbent structure with the desired functional and performance parameters.

BACKGROUND OF THE INVENTION

Functional requirements imposed on disposable absorbent articles, such as diapers, include the absolute elimination of any leakage, a dry feeling of the user and adaptability and a comfortable fit throughout their functional life. Therefore, such absorbent articles typically comprise an absorbent core that serves to provide controlled control of the acting fluid and other characteristic absorbent properties required to meet the above functional requirements. The absorbent core of such articles typically consists of wood pulp in fibrous form, and in most cases superabsorbent material is distributed in the absorbent core, which serves to increase the absorbency of the acting liquid. The absorbent core typically has a "hourglass", "T" shape, or similar configuration with reduced width of the absorbent structure in the central crotch region to provide adequate fit and comfort for the user.

In many cases, absorbent articles leak before the absorbent capacity of the absorbent core as a whole is fully utilized. One problem that causes leakage is the inability of the absorbent core to rapidly and completely absorb the acting liquid when a large amount of the liquid is introduced into the absorbent article during the impact of the liquid. Another problem that may be the cause

427 / B of unwanted leakage, is the inability of the absorbent core to distribute or displace, between the individual impacts of a liquid, a sufficient amount of liquid from the absorbent article receiving zone section to more and more distal end regions of the absorbent core that have not been utilized. This leads to saturation of only the central absorbent zone of the absorbent core and to the formation of excessive thickness, high bulkiness, densification and collapse of the absorbent structure in the wet, resulting in poor efficiency, improper application deposition and user discomfort. Said drawbacks of the absorbent cores are particularly critical for thin crotch absorbent articles having a width of less than about 4 inches in the crotch region, providing less absorbent material in the receiving zone and not being able to provide the desired functional efficacy.

The absorbent cores of current absorbent articles are unable to meet the above functional requirements. Proposals to ensure the necessary efficiency of the absorbent core, i. The rapid absorption and distribution of the acting liquid, with the upstream narrowed crotch region, based on the increased efficiency of the absorbent article, cannot be overcome with the current capabilities of the absorbent structures. Accordingly, there remains a need to provide absorbent structures capable of providing improved fluid impact processing, and improved fluid distribution and displacement between the fluid impacts, to maintain said enhanced fluid processing and to provide adequate functional lifetime for the absorbent fluid. product.

SUMMARY OF THE INVENTION

According to the present invention, there is provided an absorbent system that includes a plurality of absorbent sheet portions. Advantageously, the two or more of said layered portions may interact with each other in a manner that preferably provides for the purposeful placement of the specified liquid in the selected layered portion. Said localization of the liquid in the layer portion may increase the potential of the layer portion

427 / B for liquid transfer through capillary wicking due to the higher level of saturation and increased amount of liquid available. The absorbency of the absorbent system has been found to be conventional or improved over current absorbent systems by keeping the second layer portion of the absorbent system at low saturation levels during the maximum amount of fluid impact possible while ensuring optimal wicking by adequately controlling the properties of the composite absorbent structure. The low saturation in this layer portion provides sufficient void volume for the impact fluid to be delivered as well as high permeability, thereby increasing the suction rate of the absorbent system as a whole. The respective properties of this layer portion may advantageously be in equilibrium with a correspondingly high level of capillary stress, so as to ensure sufficient control of the transfer of the liquid and thus substantially eliminate unwanted leakage. This low-saturation controlled layer portion can additionally be used as a buffer layer material, where it can provide an additional suction function in addition to serving as a buffer for the impact of the liquid.

According to specific aspects of the present invention, the user-facing layer of the absorbent structure need not extend over the entire surface area of the absorbent system and can be configured to provide a suction layer portion that serves as an additional layer for the highly saturable suction layer portion. In the described arrangement, the suction layer portion may be located in substantially direct contact with the applied fluid, thereby allowing more immediate access to the absorbent structure into the absorbent structure and providing an improved function of sucking the fluid.

According to further aspects of the present invention, the at least one primary layer portion may exhibit an uneven, selectively distributed zonal basis weight distribution. Specific embodiments of the at least one primary layer portion may be formed such that in the at least one primary layer portion there is a receiving zone having a basis weight that is less than the basis weight of the remainder to receive liquid to receive an unspecified portion of the primary layer portion.

427 / B

According to other aspects of the present invention, the layer portions of the absorbent system may interact with each other to provide a desired liquid wicking potential, such as a liquid wicking value of at least about 16%. In addition, the absorbent system of the present invention can provide a desired flow conductivity value, for example, such as a flow conductivity value of at least about 7 x ^{10 -6} cm ³ . According to other aspects of the present invention, the proposed absorbent system may provide a combined conductivity / absorbency value of at least 14.10 ^-6 cm ³ . According to further aspects, the present invention may provide an absorbent system that is capable of providing a desired flow conductivity value and further comprises at least one layer portion having a desired liquid wicking value. According to still other aspects of the present invention, the absorbent system may comprise a superabsorbent polymerization material (SAP) that exhibits a controlled, specific uptake rate. For example, a desired superabsorbent material having a controlled rate of absorption may exhibit a specific rate of absorption, referred to as a Tau value, or a time characteristic, such as a Tau value of at least about 0.67 minutes. According to other aspects of the present invention, the absorbent system may comprise a combination of superabsorbent materials that exhibit a specific ratio of Tau values.

On the basis of the various aspects mentioned above, the present invention may provide an absorbent article having a higher efficiency absorbent structure which has a low thickness and low volume, which exhibits high absorption collection and which is resistant to unwanted leakage. Individual embodiments of the absorbent article of the present invention are capable of making better use of the potential absorbent capacity of the absorbent structure while being able to more efficiently distribute and transfer absorbed liquid from the initial acquisition zone to more distal sections of the absorbent structure located closer to their distal end regions. In addition, the absorbent structure of the present invention is capable of providing the capability of aspirating and absorbing liquid at a high rate and maintaining this desired aspiration rate even after the structure has been wetted and has reached a substantial portion of its potential overall absorbent capacity.

427 / B

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention and its further advantages will be described and explained in more detail in the following detailed description by way of specific examples of embodiments of the invention in conjunction with the accompanying drawing, in which:

Fig. 1 shows an exemplary embodiment of an absorbent article in plan view in which the absorbent system of the present invention is incorporated.

Fig. 1A shows an exemplary embodiment of the absorbent article of FIG. 1 in a cross-sectional side view.

Fig. 1B shows an exemplary embodiment of the absorbent article of FIG. 1 in a longitudinal view and in cross-section.

Fig. 2 illustrates an exemplary embodiment of an absorbent core structure according to the present invention in plan view showing a first topsheet primary layer that extends across a central region of the total surface area of the absorbent core and a second bottomsheet primary layer that extends substantially over the total areal surface area. the end layers of the first layer portion in the longitudinal direction are spaced apart from the mutually opposed end edges of the second layer portion in the longitudinal direction.

Fig. 2A shows an exemplary embodiment of the absorbent core structure of FIG. 2 in a longitudinal view and in cross-section.

Fig. 3 illustrates an exemplary embodiment of a further absorbent core structure according to the present invention in plan view showing a first topsheet primary layer that extends across a central region of the total absorbent core area and a second bottom primarysheet substantially extending throughout the total the extent of the absorbent core, the second layer portion having

427 / B an uneven, zonal basis weight distribution with a relatively higher basis weight at opposite ends thereof in the longitudinal direction, providing a reverse zonal distribution of the second, lower layer portion in the longitudinal direction.

Fig. 3A shows an exemplary embodiment of the absorbent core structure of FIG. 2 in a longitudinal view and in cross-section, wherein the selected central portion of the second layer portion has a basis weight that is less than the basis weight of adjacent, mutually opposed end portions of the layer portion in the longitudinal direction, providing an inverted zonal basis weight of the second layer portion in the receiving zone.

Fig. 4 shows an exemplary embodiment of another absorbent core structure according to the present invention in plan view having an upper primary layer portion that extends over the entire front portion of the lower primary layer portion but overlaps only a portion of the rear portion of the lower primary layer portion.

Fig. 4A shows an exemplary embodiment of the absorbent core structure of FIG. 4 in a longitudinal view and in cross-section.

Fig. 5 shows an exemplary embodiment of another absorbent core structure according to the present invention in plan view having an upper primary layer portion that overlaps the entire lower primary layer portion.

Fig. 5A shows an exemplary embodiment of the absorbent core structure of FIG. 5 in a longitudinal view and in cross-section.

Fig. 6 shows an exemplary embodiment of a further absorbent core structure according to the present invention in plan view showing an upper primary layer portion which has, compared to the lower primary layer portion, both a smaller, narrower dimension in the transverse direction and a smaller, shorter dimension in the longitudinal direction .

427 / B

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Fig. 7

Fig. 8

Fig. 9

Fig. 10

Fig. 11

Fig. 12

Fig. 13 illustrates an exemplary longitudinal and cross-sectional view of an absorbent core structure according to the present invention including a lower primary layer portion formed of a laminate in which the superabsorbent material particles are sandwiched and held between layers of liquid permeable material.

shows an exemplary longitudinal and cross-sectional view of another absorbent core structure of the present invention comprising a lower primary layer portion formed from a plurality of heterogeneous, sub-layered composite materials arranged to provide an uneven, zonal base weight in said lower primary layer portion.

shows an exemplary longitudinal and cross-sectional view of a further absorbent core structure according to the present invention comprising a lower primary layer portion formed of a heterogeneous layered material in which the distribution of superabsorbent material is arranged such that in said lower primary layer portion it provides an uneven, zonal base weight superabsorbent material.

schematic representation of a test apparatus for determining specific parameters of superabsorbent material.

shows an exemplary embodiment of a cylinder assembly disposed in a reservoir with a weight applied to a plate piston, in cross section.

shows an exemplary embodiment of a cylinder assembly disposed in a reservoir with a connecting rod for tapping the plate piston, in cross section.

shows an exemplary cross-sectional view of a cylinder assembly with a weight applied to a plate piston disposed in a vacuum clamp.

427 / B

Fig. 14 illustrates an exemplary cross-sectional view of a cylinder assembly disposed in a vacuum clamp.

DETAILED DESCRIPTION OF THE INVENTION

The following description of various aspects and embodiments of the present invention will be made in connection with a disposable absorbent article, such as a disposable baby diaper. However, it should be understood that the present invention may be applied in conjunction with other articles such as diapers; women's protective menstrual articles, adult incontinence absorbents, pads and the like, which may be formulated as disposable articles. Typically, said disposable absorbent articles, such as disposable sanitary absorbent articles, are intended for limited short-term use only, and are not intended to be laundered or otherwise cleaned for reuse. For example, a disposable diaper is discarded after being soiled by the user during functional application. In the context of the present invention, the term self-fastening system refers to a system comprising cooperating elements which are arranged to engage each other so as to provide the desired reliable and rigid fastening.

According to the present invention, there is provided an absorbent core system comprising a plurality of sheet portions as a component and capable of providing a significant increase in void volume size and efficiency, improved permeability, and improved suction efficiencies within a specified receiving zone. The absorbent system, and in particular the absorbent core of the system, is substantially capable of regenerating the desired void volume by transferring fluid away from the receiving zone, for example, through a wicking function or other mechanisms. The drained liquid may advantageously be collected in the layer portion of the absorbent core that is intended to provide the desired, relatively large distribution of the acting liquids, while the layer portion intended to provide

427 / B of the corresponding void volume and liquid soaking can be maintained in a relatively low saturation state. In the vast majority of cases, the layer portions may be configured with relative basis weights or concentrations of superabsorbent materials and arranged such that suitably cooperating materials with appropriate, appropriate capabilities will be capable of being incorporated into the system and providing reliable functional efficiency. However, it has been found that certain specific combinations of these materials, compared to others, are capable of providing substantially improved functional efficiency and performance. In addition, it should be taken into account that the basis weights or other capabilities of the individual components of the materials are possible, in order to optimize costs and other user parameters or to ensure the desired distribution and distribution of the absorbed liquid, in specific areas or zones of the absorbent structure (e.g. , the facing layer depending on the back, reverse side).

According to the present invention, the absorbent layer portions may be substantially configured to cooperate in a manner in which the displacement and location of the absorbed liquid is preferably performed in one or more predetermined or determined layer portions. Said localization of the absorbed liquid into the volume of the designated layer portion is capable of increasing the potential of the layer portion for displacing and distributing the liquid through capillary capillary action, thereby allowing relatively higher levels of saturation and absorption of the increased amount of liquid to be achieved in the predetermined layer portion.

The absorbency of the absorbent system, especially the absorbency of the absorbent core, can be maintained at a conventional level or improved by maintaining the primary, absorbent layer portion of the absorbent system at low saturation levels over the maximum possible number of liquid impingement on the absorbent article compared to standard absorbent systems. while providing optimal suction efficiency by adequately controlling the properties of the composite structure. The relatively low level of liquid saturation in said intake layer provides a corresponding void volume for subsequent liquid impact, as well as a high

427 / B permeability and thus increased suction speed of the absorbent system as a whole. Advantageously, the suction layer portion can be configured to provide reasonably high levels of capillary stress to provide adequate controlled fluid displacement control to substantially eliminate unwanted fluid leakage. Due to this low saturation, the suction layer portion is desirably additionally applied to a separately provided alignment section or layer and can provide an additional suction capability that is additional to the suction capability provided by the alignment layer material.

In specific embodiments, the suction layer portion may be disposed on the skin facing the wearer side of the absorbent structure, and may be configured not to extend over the entire surface area of the absorbent structure as a whole. Accordingly, the primary skin-facing layer portion is used as a suction layer portion and at the same time is not used as a highly saturable absorbent layer portion. Moreover, this arrangement allows the suction layer portion to be positioned in a substantially direct contact with the applied fluid, thereby allowing a much more direct access of the fluid supplied and a much more efficient suction performance.

The layer portions may be designed, singly or in combination, to provide an improved balance of efficiently performing liquid intake and distribution functions, particularly water-based liquid intake and distribution functions. Improved efficacy can be ensured, for example, by modifying the physical and / or chemical composition of the materials of the individual components of the absorbent structure or by modifying the body configurations of the components.

Standard fibrous materials and superabsorbent polymerization composite materials (SAPs) used to form conventional prior art absorbent articles, such as diapers, are capable of providing conventional combinations of functions such as aspiration, distribution, and retention retention. However, there is a continuing need to provide a number of functionally effective materials and improved absorbent systems and materials

427 / B structures which, in combination, are capable of providing increased levels of efficient suction, distribution and deployment, and retention retention of the acting fluid. In order to provide improved resistance to unwanted leakage, improved materials are incorporated into the absorbent system of the present invention, wherein the materials exhibit improved properties and capabilities in at least one of the functional areas or zones. These measures may result in an improvement in the complex functional effectiveness of the absorbent system as a whole.

The suction function can be adjusted and controlled, for example, by control parameters, including the size of the fibers and particles of the materials present in the respective layer portion, the voidiness of the respective layer portion, the basis weight of the respective layer portion and the qualitative and quantitative composition of the respective layer portion. The distribution can be adjusted and controlled, for example, by appropriate selection or by influencing control parameters, including the size of the fibers and particles of the individual components of the materials used, the wetting angles of the materials used, the surface tension of the liquids applied and the basis weights of the materials used.

In order to further improve the desired balance of absorbent properties, a number of other significant parameters have been identified that can provide the layered portions with a higher functional efficiency when combined with each other and consequently provide an improved functional efficiency of the absorbent system as a whole. The parameters include a flow conductivity setpoint and a liquid soak setpoint provided by the absorption system. Another additional factor to assess the overall functional efficiency of the absorbent system is the combined conductivity / wicking value.

The flow conductivity is a value that is based on the physical properties of the absorbent materials, and in particular those absorbent materials that are disposed in the absorbent zone of the absorbent system and are related to the absorbency provided by the absorbent core structure. Is a

427 / B is suitable and desirable if the flow conductivity is not less than about 2.5 x 10 cm ³ . Alternatively, in order to provide improved efficiency, the flow conductivity value is not less than 3.10 < ³ > cm &^lt; ^{3 &gt}; According to other aspects of the present invention, the flow conductivity may be up to about 5 x 10 ⁶ cm ³ . Alternatively, to provide improved efficacy, the flow conductivity may be up to about 7.10 < ³ > cm < ^{3 >} and optionally the flow conductivity may be up to about 9.10 < ³ > cm &^lt; ^{3 >} or more.

The potential liquid wicking value (or liquid wicking value) is a functional performance parameter that relates to the amount of liquid removed and displaced from the absorbent structure acquisition zone described above during wicking in the vertical direction. This value represents the ability of the absorbent structure to remove and displace the applied liquid from the acquisition zone between the individual impacts of the liquid, for which purpose at least one layer portion of the absorbent system is configured to provide a desired liquid wicking potential. Suitably and desirably, the at least one layer of the absorbent system, in particular the at least one primary layer portion of the absorbent core, is capable of providing a liquid wicking value of not less than at least about 10%. Alternatively, it provides a liquid wicking value of not less than about 15% and an optional value of not less than about 20%. According to other aspects of the present invention, the absorbent system is capable of providing a liquid wicking value of up to about 60%. Alternatively, to provide improved efficacy, the liquid wicking value provided may be up to about 65%, and optionally may be up to about 70% or more.

The combined conductivity / wicking value (C) of the absorbent system may be at least about 14.10 < 6 &^gt; cm &^lt; ^{3 &gt};. Alternatively, in order to provide improved performance, the combined conductivity / absorbency value may be at least 15.10 " cm < ^{3 >} and optionally may be at least about 16.10 &^lt; ^{3 &gt}; cm &^lt; ^{3 &gt}; In other embodiments, the combined conductivity / absorbency value may be at least about 18.10 &^lt; ^{3 &gt}; cm &^lt; ^{3 &gt}; to provide improved performance.

427 / B

In embodiments of absorbent articles having a low thickness and narrowed crotch sections, the receiving zone of the article, in its dry state, does not usually exhibit sufficient void volume available to effectively absorb the initial impact of a liquid, such as urine. Said gap volume deficiency can be compensated by incorporating a specifically configured superabsorbent polymerization material (SAP) in an amount sufficient to absorb the feed liquid during the duration of its impact. The SAP system incorporated into the absorbent system is configured to absorb and maintain the amount of liquid to be absorbed during its impact so as to provide the required leak resistance.

Although some of the parameters have been described in detail above, there remains a problem of ensuring an effective combination of these parameters and the properties described by them in a single composite structure while maintaining the desired user properties. The solution to these problems has, to date, been increasingly oriented towards the requirement of the presence of relatively low amounts of superabsorbent polymerization materials (SAP), either in the absorbent structure as a whole or in individual layers arranged therein. However, the use of a low SAP concentration in the absorbent article volume may, due to the necessity, provide the desired absorbency and retention collection and lead to an excessive increase in the thickness of the absorbent article. For this reason, an attempt has been made to provide an absorbent structure in which one absorbent layer exhibits a low SAP concentration to increase liquid wicking, while a high SAP concentration is maintained in the other absorbent layer to achieve the ultimate thin absorbent article with the desired absorbency and retention collection. . Such systems, however, do not provide the desired levels of functional efficacy since the treating fluid may preferably be moved to areas containing relatively higher concentrations of SAP. In this state, the amount of residual liquid present in the layer portion containing the relatively lower SAP concentration may be insufficient to provide the desired absorbency levels.

427 / B

To overcome these drawbacks, according to a specific aspect of the present invention, the absorbent system may comprise a controlled proportion of superabsorbent polymerization material (SAP). By using a controlled proportion of SAP in the absorption system, for example a selected, slightly reduced proportion of SAP, it is possible to maintain a high liquid concentration in the fibrous structure of the determined distribution layer portion even if said distribution layer portion contains a selected amount of SAP. In specific embodiments, the controlled reduced proportion of SAP is primarily located in a layer portion other than the distribution layer portion. As a result, the low SAP portion may be in a saturated state while maintaining the overall absorbency of the thin absorbent article at the desired high level. It is contemplated that other alternative mechanisms, other than the inclusion of a reduced proportion of SAP in the absorbent structure, may be used to provide the desired absorbency distribution and different concentrations of absorbed liquid between the selected layer portions. The desired absorbency distribution can be ensured, for example, by the selective configuration of the relative wettability and / or density of the layer portions.

Referring to FIG. 1 and 2, it can be seen that the absorbent composite system 26 of the present invention includes a liquid shock absorber 84 and a structural absorbent pad or core 30. The absorbent core 30 has a multilayer structure of absorbent layer portions, wherein the characteristics of the individual layer portions are selected. and configured by adjusting and balancing the capability of receiving and soaking the acting fluid to provide enhanced functional efficacy against undesired leakage.

Generally speaking, the absorbent core 30 of the present invention begins (taking in the direction of displacement of the liquid from the skin closest to the wearer facing surface of the absorbent article outwardly, at the furthest distance from the wearer's skin surface) of the first absorbent layer containing the superabsorbent material together. with any component selected necessary to maintain the integral integrity of said component

427 / B layer as a whole during functional action. This first layer is required to contain a minimum amount of superabsorbent material that is not less than about 5% by weight. The absorbent core 30 is terminated (taking in the direction of displacement of the liquid from the skin closest to the wearer facing surface of the absorbent article outwardly, at the greatest distance from the wearer's skin surface) the last absorbent layer immediately prior to the substantially liquid impermeable layer. a layer which forms a protective barrier against undesired leakage of liquid from the absorbent article. Accordingly, the absorbent core 30 in the illustrated embodiment includes a first primary absorbent layer 48, an outer or outer shell layer 28 or 36 and respective components sandwiched therebetween. In addition to the absorbent core, the absorbent article further includes a topsheet 24, a leveling layer 84 that is free of superabsorbent material, and a backsheet 22.

The corresponding balance of capability to absorb and soak the acting fluid may be represented by various determining parameters, such as flow conductivity, potential liquid wicking, basis weight, particle size, fiber proportions, and the like, as well as combinations thereof. The flow conductivity of the absorbent material is related to the available void volume and structure permeability during the various levels of saturation typically encountered in normal functional use. In order for the absorbent system to provide improved functional efficacy, it is necessary to allow the acting liquid to enter the absorbent structure at a rate as close as possible to the velocity at which the acting liquid is introduced into the absorbent structure. For the purpose of characterizing the suction potential of the absorbent core 30 as a whole, and in particular the suction potential of the absorbent system 26, a flow conductivity value may serve. In addition, an important parameter is to move the acting fluid away from the inlet zone, the purpose of which is to accumulate liquid in the far regions of the absorbent structure and to regenerate and prepare the inlet zone to receive the next impact of the liquid with much greater efficiency. For characterization purposes

427 / B of the absorbent structure's ability to remove the applied liquid from the acquisition zone between two successive impacts of the liquid may serve the liquid wicking value.

Referring to FIG. 2 and 2A, the absorbent core 30 has an overall length 66 of the composite absorbent core, an overall width 68 of the composite absorbent core, a total thickness 70 of the composite absorbent core, a crotch region width 58 of the absorbent core, and a predetermined upstream end edge of the absorbent core. The delimitation of the foremost end edge serves to determine its location on the front waistband portion of the absorbent article. As can be seen from FIG. 2, the assembly of the individual components of the absorbent core 30 extends over and overlaps the entire determined range of the absorbent core. Individual components, respectively. The layers, and optionally sub-layers, may extend over the entire absorbent core range to provide the desired functional effectiveness. In addition, each of said individual layer portions has individual dimensional dimensions. For example, in the embodiment shown, the first layer portion 48 has a first thickness (height) 72, a first length 73, and a first width 74. The second layer portion has a second thickness (height) 75, a second length 66, and a second width 68.

Referring to the total length of the absorbent core 66, the designated acquisition zone 52 of the absorbent structure for absorbing the applied liquid is a portion of the absorbent core that begins at a transversely extending transverse line positioned at a position within 24% of the total length of the absorbent core. and extending to a second transversely extending, transverse line positioned at a position spaced 59% of the total length 66 of the absorbent core from said frontmost end edge. In the embodiment shown, the absorbent core acquisition zone may be, for example, an area of the absorbent structure that begins on a transverse direction extending approximately 3.5 inches (89 mm) from the foremost end edge of the absorbent core and extends in the transverse direction. a extending line spaced approximately 8.5 inches (126 mm) from said foremost end edge.

427 / B

Increasing the flow conductivity value by increasing the volume of the absorbent core structure has been rejected as undesirable because the absorbent articles having a narrow crotch region exhibited an excessive increase in the thickness of the finished product. Consequently, there is still a need for absorbent systems having a configuration that is capable of providing the desired suction efficiency, represented, for example, by a flow conductivity value, while maintaining a small thickness of the absorbent core 30 and a small thickness of the absorbent system 26. the absorbent core 30 has a total dry thickness of not more than about 6 mm. Alternatively, the absorbent core may have a thickness of not more than about 5.3 mm and optionally a thickness of not more than about 5 mm such that the absorbent core is capable of providing the desired functional effectiveness. According to another aspect of the present invention, the absorbent core 30 may have a dry thickness of no more than about 25% of the width of the crotch region of the absorbent core. Alternatively, the absorbent core 30 may have a thickness of not more than about 20% of the width of the crotch region and optionally a thickness of not more than about 15% of the width of the crotch region so that the absorbent core is capable of providing the desired functional efficacy. For purposes of the present description, the crotch region width of the absorbent core is determined as the narrowest (smallest) dimension of the crotch region in the transverse direction contained in the absorbent core receiving zone.

Further, it is desirable for the absorbent system 26 to have a total total thickness of not more than about 6 mm in the dry state. Alternatively, the absorbent system may have a thickness of not more than about 7.3 mm and optionally a thickness of not more than about 7 mm such that the absorbent system is capable of providing the desired functional efficacy. According to another aspect of the present invention, the absorbent system 26 may have a thickness that is no greater than about 30% of the width of the crotch region of the absorbent system. Alternatively, the absorbent system 30 may have a thickness in the dry state of no more than about 25% of the width of the crotch region, and optionally a thickness of no more than about 20% of the width of the crotch region so that the absorbent system is capable of providing the desired functional efficacy.

427 / B

For the purposes of the present disclosure, the dry width is measured at a controlled limited pressure of 0.2 psi (1.38 kPa).

According to another aspect of the present invention, the low-section absorbent system 26, and in particular the absorbent core 30, may have a crotch region 54 to be positioned between the wearer's legs, the narrowest (smallest) dimension of the crotch region transversely located in the receiving zone 52. crotch area. Accordingly, an adult absorbent article (intended for functional use by adults, i.e., over the age of 13) may exhibit a minimum width of the crotch region 54 in the transverse direction of not more than about 5 in the dry state of the composite absorbent structure. 5 inches (about 14 cm). Alternatively, such a product may have a minimum width of the crotch region 54 that is not greater than about

4.5 inches (about 11.4 cm) and optionally may have a minimum width not greater than about 3.5 inches (about 8.9 cm) to achieve the desired assurance of improved fit and comfort in application. An absorbent article intended for juveniles (intended for functional use by juveniles below the age of 13) may exhibit a minimum width of the crotch region 54 in the transverse direction of not more than about 4 inches (about 10 cm) in the dry state of the composite absorbent structure. Alternatively, the article may have a minimum width of the crotch region 54 that is not greater than about 3 inches (about 7.6 cm) and optionally may have a minimum width that is not greater than about 2 inches (about 5.1 cm) such that to achieve the required assurance of improved storage and application comfort.

Further, for the functional purpose of the absorbent system, it is important to remove the acting liquid from its receiving zone 52 so as to effectively prevent excessive saturation of said liquid in the zone and consequently unwanted release of said liquid from the absorbent article. The ability of the absorbent system to move or distribute the acting liquid from the acquisition zone may be represented by the value of the potential wicking of the liquid provided by the absorbent system. The value of potential liquid wicking capacity is related to the amount of liquid that the absorption system is able to move from the receiving zone when the receiving zone shows a liquid loading / saturation level of 1.0 g liquid per liquid.

427 / B centimeter of the acquisition zone of the composite absorbent structure. Accordingly, the present invention provides a specific layered absorbent system having a low thickness, narrowing in the crotch region and having a small volume.

The layer portions are arranged in the absorbent system to include a first skin layer facing the user's skin that may have different shape configurations suitable for the purpose, but typically has a size not greater than the outer range of the second layer portion. The first, topsheet portion is capable of maintaining saturation at a low level while at the same time having a high flow conductivity value during functional use of the absorbent article when used in combination with the second, bottomsheet portion. The second, lower layer portion may have an optional shape, for example, an "hourglass" or a "T," and is configured to efficiently distribute and displace the acting liquid from the acquisition zone of the absorbent composite structure. In particular, the second, lower layer portion is capable of providing the desired values of potential liquid wicking, which can be determined using the "Potential Liquid Wicking Value" procedure described in detail below.

Referring to FIG. 1, 1A and 1B, the present invention may provide a disposable sanitary absorbent article, for example, a diaper 20 having a longitudinally extending longitudinal direction 86 and a transversely extending width direction 88. The absorbent article comprises a first waistband portion, e.g. a belt portion, for example, a front belt portion 38 and an intermediate crotch region 42 that interconnects said first and second belt portions. The front waist panel 38 is provided with a pair of transverse direction opposite side end regions 118 of the front waist panel, the rear waist piece 40 is paired with transverse direction of opposite side end regions 116 of the rear waist panel and the intermediate crotch region 42 provides a respective crotch region of the absorbent product which is placed between the user ' s legs during functional application.

Fig. 1 shows an exemplary embodiment of a disposable diaper 20 according to the present invention, which is shown fully in FIG.

427 / B of the unfolded, unstretched state (i.e., in a state in which all the elastic elements causing extinguished gathering and contraction are contained in the absorbent article). Some parts of the structure of the absorbent system are partially removed for more obvious explanation of the inner configuration of the diaper, and this diaper is shown in a view of the surface area closest to the skin of the wearer facing layer. The outer edges of the diaper define, by means of longitudinally extending lateral end edges 110 and transversely extending front end edges 112, an outer circumferential boundary thereof. In addition, the side end edges 110 define a leg or foot area cutout and optionally are curved or otherwise contoured.

The liquid-permeable topsheet 24 is laminated in the front to the substantially liquid impermeable backsheet 22, and an absorbent system is operatively disposed and secured between the topsheet and backsheets 24 and 22. An exemplary embodiment has an absorbent system 26 that includes a buffer layer 84 to compensate for the impact of a liquid and a retention portion for maintaining and accumulating the liquid. Said retention portion of the absorbent system comprises an absorbent core 30. In the embodiment shown, the equalizing layer 84 is a layer which is conveniently disposed between the absorbent core and the topsheet layer 24. However, other arrangements may be used. For example, the alignment layer 84 may optionally be positioned between the absorbent core and the backsheet 22, or directly on the user-facing surface of the topsheet.

The absorbent article further typically includes elastic or elastomeric elements, for example, leg region elastic elements 34 and waist region elastic elements 32, and the alignment layer 84 is arranged in fluid communication with the retention portion of the absorbent system. The topsheet 24, the backsheet 22, the absorbent core 30, the alignment layer 84, and the elastic members 34 and 32 may be assembled into various diaper configurations known in the art. Additionally, the diaper may include a set of regulatory retention strips 82 and side panels 90 that may be elasticized or otherwise treated to be elastic.

427 / B

Examples of such absorbent articles that include elasticized side panels and optionally configured fastening strips are described in U.S. patent application Ser. 168,615. T. Roessler et al., Entitled "Diaper Functional Accessories", filed December 16, 1993 (cf. Verified Annotation and Brief Content No. 10,961). Various technological processes for making the desired fastening systems having correspondingly appropriate functional effects are further described in U.S. Pat. No. 5,399,219, T. Roessler et al., Entitled "Method of Making a Fastening System for Diaper Functional Accessory", published March 21, 1995 (cf. Verified Annotation and Brief Content No. 11,186), U.S. Pat. No. 286,086, D. Fries, entitled " Method of Completing Elasticized Fastening Strips ", filed Aug. 3, 1994 (cf. Verified Annotation and Brief Content No. 11,169), which was published as a US patent. No. 5,540,796 and U.S. Pat. No. 08 / 415,383, D. Fries, entitled " Method of Completing a Laminated Tape ", filed April 3, 1995 (cf. Verified Annotation and Brief Content No. 11,950), published as U.S. Pat. 5,595,618. The full descriptions of the documents described above are hereby incorporated by reference into the present invention and are hereby incorporated into the present invention (without limiting the scope thereof in any conflicting manner).

The diaper 20 is as can be seen from its exemplary representation of FIG. 1, generally defined by the longitudinally extending longitudinal direction 86 and the transversely extending longitudinal direction 88. The diaper may have any desired shape configuration, for example, a rectangular shape, an "1," hourglass shape (middle tapered shape), " or "T". When using a T-shaped configuration, the horizontal bar "T" may form the front waistband portion of the diaper, or alternatively, may form the back waistband portion of the diaper.

The topsheet 24 and the backsheet 22 may generally have the same surface area and may have dimensions, i. the length in the longitudinal direction and the width in the transverse direction, which are generally generally greater than that extending across and beyond the corresponding dimensions, the length and width of the absorbent system 26 to form corresponding portions of the edge side edges 110, and

427 / B boundary end edges 112 that extend around the boundary end edges of the absorbent system. The topsheet 24 is mated laminated to the backsheet 22 to define the perimeter of the diaper 20. The diaper waistband portions 38 and 40 include those sections of the diaper that, either in full or in part, overlap or surround the wearer ' s belt or its parts near its crotch. An intermediate crotch region 42 is formed between the waistband panels 38 and 40 and is joined together to form a portion of the diaper which is conveniently disposed between the user ' s legs and overlaps his crotch in the groin area during functional application of the diaper. Thus, the intermediate crotch portion 42 is the area of the diaper exposed to repeated fluid impact, typical and characteristic of using the diaper or any other disposable absorbent article.

The backsheet 22 may typically be located outside the surface of the composite absorbent system 26 and may consist of a liquid pervious material, but it is desirable to be formed of a material configured to be substantially impervious to liquids. Accordingly, the characteristic backsheet may be formed, for example, from a thin plastic film or other flexible and liquid-impermeable material usable for this purpose. By the term "flexible (materials)" used in accordance with the description of the present invention is meant materials that are compliant and that will readily conform to the general shape and contour profile of the user's body. The function of the backsheet 22 is to prevent the wetting and eventual soiling of articles such as bed linen or user underwear in contact with the diaper 20, body exudates contained and retained in the composite absorbent system 26. In specific embodiments of the present invention, the backsheet 22 comprises a thin film, such as a thin polyethylene film, with a thickness ranging from about 0.012 to about 0.051 mm (0.5 to 2.0 mils). For example, the backsheet film may have a thickness of about 1.25 mils.

427 / B

Alternative embodiments of the backsheet may consist of a layer of woven or nonwoven fibrous fabric that may be either wholly or partially formed or processed to achieve desired levels of liquid impermeability in selected areas adjacent to or disposed in close proximity to the absorbent core. Thus, the backsheet may, for example, comprise a gas permeable nonwoven fabric layer laminated to a thin polymeric film layer. Other examples of fibrous, fabric-like backsheet materials may include a stretch-tapered or stretch-heat laminate consisting of a 0.6 mil (0.015 mm) blown polypropylene film and a 0.7 ounce basis bonded polypropylene material. square yard (23.8 g per square meter) (fiber with a weight denier of 2 denier). This material forms an outer protective layer of diapers known as "HUGGIES SUPREME" marketed by Kimberly - Clark Corporation. Typically, said backsheet 22 provides an outer protective layer for the absorbent article. Optionally, however, the absorbent article may comprise an outer protective layer as a separate discrete component, which in addition is attached to the backsheet.

The backsheet 22 may alternatively include a microporous "breathable" material that explicitly permits the permeation of gases such as water vapor from the composite absorbent system 26 while substantially eliminating and preventing the passage of liquid body exudates through the backsheet. For example, the breathable backsheet may consist of either a thin microporous polymerization film or a nonwoven fabric that is coated or modified to achieve the desired liquid impermeability levels. A suitable microporous film useful herein may be, for example, PMP-1, commercially available from Mitsui Toatsu Chemicals, Inc., with a sales office in Tokyo, Japan; or XKO-8044 polyolefin film, marketed by 3M Company, Minneapolis, Minnesota. In addition, the backsheet may be further subjected to a crimping or other treatment

427 / B technology, providing a finished relief or matte finish in a finished state having an aesthetically acceptable and pleasant exterior appearance.

In various configurations of the present invention in which the absorbent article components, such as the backsheet 22 or the regulatory retention strips 82 are designed to exhibit both gas permeability and, at the same time, penetration resistance and limited permeability of water-based liquids, a liquid-resistant material arranged to be capable of withstanding the pressure exerted by a static height of 45 cm water column without causing any substantial leakage or leakage of the applied liquid. A suitable technological procedure for determining the material's resistance to liquid penetration is described in the Federal Test Standard FTMS 191 "Test Method 5514", published December 31, 1968.

Size, resp. the extent of the backsheet 22 is typically limited by the size of the absorbent system 26, respectively. an absorbent core 30 and a specifically selected diaper configuration. The backsheet 22 may have a generally T-shaped, generally L-shaped, or modified configuration in the middle of a tapered hourglass, with a predetermined distance, such as a distance of about 1.3 cm. to about 2.5 cm (from 0.5 to 1.5 inches), extending beyond the end edges of the absorbent core 30 to form outwardly extending side and front end edges.

The topsheet 24 is a skin-facing surface that is in contact with the skin when applied, is pliable, soft to the touch, and does not cause skin irritation. Further, the topsheet 24 may exhibit less hydrophilic capabilities than the composite absorbent system 26 while being sufficiently porous to provide liquid permeability so as to explicitly allow liquid to readily pass through its bulk thickness into the volume of the composite absorbent system 26. Corresponding topsheet 24 can be formed from a wide selection of fibrous materials, such as, for example, a well foam material, a cross-linked foam material, a perforated plastic film, a natural fibrous material

427 / B materials (for example, wood or cotton fibers), synthetic fibrous materials (for example, polyester or polypropylene fibers) or a combination of natural and synthetic fibrous materials. The topsheet 24 is specifically utilized to assist in insulating the wearer ' s skin from the liquids that are retained and accumulated in its composite absorbent system 26.

Various types of woven or nonwoven fabric can be used to form the topsheet 24. The topsheet may be formed, for example, of blown or spunbonded webs or webs consisting of selected fibers on demand, and may additionally be formed of carded, wet-spun webs by stitching fibers of the reinforced webs or similar materials, as well as combinations thereof. Said fabrics may consist of natural fibers, synthetic fibers or combinations thereof. Optionally, the topsheet may comprise a cross-linked material or a perforated film as part of it.

For purposes of the present invention, the term " nonwoven " refers to a web of fibrous material that is formed in a manner other than that of textile weaving or knitting. As used herein, the term " woven fabric " means all woven, knitted and nonwoven fibrous materials, webs or webs, and combinations thereof.

The fabrics for forming the topsheet may consist of a substantially hydrophobic material, which hydrophobic material may optionally be treated with either a surfactant or other suitable technology known in the art to achieve the desired wettability and hydrophilic properties. In a specific embodiment of the present invention, the topsheet 24 is formed from a spunbonded, spunbonded polypropylene fabric consisting of fibers having a weight of yarn of from about 2.8 to about 3.2 denier, processed as a web, and has a basis weight of about 22 g. / m ² and a density of about 0.06 g / cm ³ . This fabric is subjected to surface treatment using a 0.28% Triton X-102 surfactant solution. Said surfactant may

427 / B may be applied to the surface of the web by any of the commonly used means or technologies, for example by spraying, printing, brushing or the like.

The topsheet 24 and backsheet 22 are joined or otherwise joined together in a functional manner. As used herein, the term "interlocked" includes both configurations in which the topsheet 24 is bonded to the backsheet 22 directly by directly attaching the topsheet 24 to the backsheet 22, and configurations in which the topsheet 24 is connected indirectly to the backsheet 22 by attaching the topsheet 24 to the interposed components, which are then successively, one after the other, attached to the backsheet 22. The topsheet 24 and the backsheet 22 they may be coupled to one another, for example, around the circumference of the diaper by means of attachment means (not shown in the accompanying drawing), such as adhesive bonds, ultrasonic bonds, thermal bonds, lamellas, stitching or any other of the state The fastening means known in the art, as well as combinations thereof. For example, such means as a uniformly arranged compact adhesive layer, an adhesive layer arranged in an embossed configuration, a spray-applied adhesive layer or an adhesive layer formed by a set of individual, separated strips, segments or dots may be used to attach the topsheet 24 to the backsheet 22. adhesive. It will be apparent to those skilled in the art that the above-mentioned attachment means may be used to adequately couple and attach to each other and the various other components or integral parts of the absorbent articles described herein.

427 / B

An exemplary embodiment of an absorbent article is provided with a composite absorbent system which includes, as part of, a buffer layer 84 to compensate for the impact of a liquid and a retention portion for retaining and storing absorbed body fluids and other exudates. According to specific aspects of the present invention, the retention and accumulation portion is secured by the absorbent core 26 shown, comprising a plurality of layers formed of specifically selected fibrous materials and particles of a highly absorbent material. The illustrated absorbent core composite absorbent system is conveniently positioned and sandwiched between the topsheet 24 and the backsheet 22 to form the diaper 20 as a whole. In this state, the composite absorbent system exhibits a structural arrangement that generally provides for its compressibility and conformability, while not causing undesirable irritation to the skin surface of the wearer while being able to absorb and retain liquid body exudates.

Depending on the type of individual configurations of the absorbent article of the present invention, the types of wettable hydrophilic fibrous materials may be different and suitable for forming the individual components of the absorbent article. Examples of such useful fibrous materials include naturally occurring organic fibrous materials consisting of an inner wettable material, for example cellulose fibers; synthetic fibrous materials consisting of synthetic cellulose or derivatives thereof, for example, regenerated cellulose fibers; inorganic fibrous materials consisting of an inherently wettable material, for example glass fibers; synthetic fibers formed from naturally wettable thermoplastic polymers, in particular polyester or polyamide fibers; and synthetic fibrous materials formed from non-wettable thermoplastic polymers, particularly polypropylene fibers. Said fibrous materials may be treated to improve hydrophilic properties, for example either by treatment with silica or by treatment with a material having a corresponding hydrophilic fraction and which cannot be easily removed from the treated fibers,

427 / B and / or sheathing non-wettable hydrophobic fibers with a protective coating of hydrophilic polymer, either during or after the formation of the fibers. For the purpose of forming the absorbent article of the present invention, or individual parts thereof, it is likewise contemplated to use different blends of the various types of fibrous materials referred to above, based on the respective requirements.

As used herein, the term " hydrophilic " means fibrous materials or surfaces formed from such fibrous materials that are wettable in contact with a water-based liquid. The degree of wettability of said materials can be described on the basis of the wetting angles and surface tension of the liquids and respective materials. Test apparatuses and related test procedure technologies suitable for measuring and determining the wettability of individual fibrous materials or mixtures of such fibrous materials may be provided, for example, by the "Cahn SFA-222 Surface Force Analyzer System" for surface tension measurement or other analogous devices. Based on testing using said test apparatus, fibrous materials having a liquid wetting angle of less than 90 ° are referred to as "wettable", while fibrous materials having a liquid wetting angle of greater than 90 ° are referred to as "non-wettable".

Specifically, the absorbent core 30 of the composite absorbent system may comprise one or more fibrous matrices, such as, for example, a fabric of natural fibers, synthetic fibers, and the like, as well as combinations thereof. It is desirable that said fibrous materials be hydrophilic, either because of their natural nature or through the effects of their processing to increase the hydrophilic properties in a conventional manner. Specific arrangements may include a fibrous matrix consisting of fibrous fluff-shaped cellulose. It will be appreciated from the above that each of the primary sheet portions, i. the first primary layer portion 48 and the second primary layer portion 50 may comprise either the same types of fiber matrices or, in contrast, different types of fiber matrices.

427 / B

According to specific aspects of the present invention, the respective fiber matrices of the primary layer portions 48 and 50 may be admixed with or otherwise embedded in the particles of highly absorbent material. The fibrous materials are arranged in the selected layer or layers into an absorbent matrix, and it is desirable that each of said primary layer portions 48 and 50 may comprise at least one fibrous material combined with particles of a highly absorbent material. For example, in specific embodiments, the defined absorbent core layers 30 may comprise a mixture of superabsorbent hydrogel-forming particles and natural fibers, synthetic meltblown polymerization fibers, or a mixture of superabsorbent hydrogel-forming particles and a combined fibrous material consisting of a mixture of natural fibers and / or synthetic polymeric fibers. Said particles of superabsorbent material may essentially form either a homogeneous mixture or an unevenly mixed mixture with the hydrophilic fibrous materials. For example, the concentration of superabsorbent particles in the composition may have a discontinuous gradient as it does not change continuously over a substantially significant portion of the thickness of each layer of absorbent structure (Z-axis), with lower concentrations closer to the user's skin. toward the garment of the wearer facing the surface of the absorbent structure. Suitable and suitable Z-axis concentration gradient configurations are described in U.S. Pat. No. 4,699,823, issued October 13, 1987 to Kellenberger et al., The entire disclosure of which is hereby incorporated by reference into the present invention, and thus becomes part of the disclosure of the present invention (without limiting its scope in any way). Alternatively, the concentrations of superabsorbent particles may be configured with a discontinuous gradient over a substantially significant portion of the thickness of each absorbent structure layer (in the Z-axis) with higher concentrations closer to the user's skin facing surface and relatively lower concentrations outwardly towards the wearer's facing surface. structure. The superabsorbent particles may further be arranged to form a generally separate, separate layer disposed within the interior of the fibrous matrix formed of hydrophilic fibrous materials. In addition, the absorbent structure may comprise two or more different types

427 / B superabsorbent material, which are optionally arranged at different locations in or on the interior of the respective fiber matrix.

The highly absorbent material may include gel-forming absorbent materials, such as superabsorbents. These gel-forming absorbent materials can be natural, modified natural and synthetic polymers and materials. In addition, the gel-forming absorbent materials may be inorganic materials such as silica gels or organic compounds such as crosslinked polymers. By the term " cross-linked " is meant the consequence of using any means to form water-soluble, substantially water-insoluble but swellable layers on the normal state. Said compositions may include, for example, network bonds, crystalline domains, covalent bonds, ionic complexes and bonds, hydrophilic bonds such as hydrogen bridges, hydrophobic bonds, or bonds via the Van de Waals forces.

Examples of synthetic absorbent gel forming polymerization materials include the alkali metal and ammonium salts of polyacrylic and polymethacrylic acids, polyacrylamides, polyvinyl ethers, maleic anhydride copolymers with vinyl ethers and alphaolefins, polyvinylpyrrolidine, polyvinylmorpholinone, polyvinyl alcohol, mixtures thereof, and mixtures thereof. Other suitable polymeric materials useful in the manufacture of the composite absorbent system include natural and modified natural polymers, such as hydrolysed acrylonitrile grafted starch, grafted acrylic acid starch, methylcellulose, hydroxypropylcellulose, and natural rubber mixtures, such as alginates, xanthan gum, xanthan gum. gum and the like. In addition, mixtures of natural and wholly or partially synthetic absorbent polymerization materials can be used for the purposes of the present invention. Other useful gel-forming absorbent materials are described in U.S. Pat. No. 3,901,236, Assarsson et al., Issued Aug. 26, 1975. Techniques for preparing said synthetic absorbent gel-forming polymers are described in U.S. Pat. No. 4,076,663, Masuda et al., Issued Feb. 28, 1978; and U.S. Pat. No. 4,286,082, Tsubakimoto et al., Issued Aug. 25, 1981.

427 / B

Characteristic synthetic gel-forming absorbent materials are xerogels which form hydrogels when wetted with liquid. However, the term " hydrogel " is commonly used for both wettable and non-wettable forms of said material.

As mentioned above, the highly absorbent material used to form the absorbent core 30 may be a gel forming superabsorbent material, wherein the superabsorbent material may be in the form of discrete particles separated from each other. Said particles may have any desired shape configuration, such as a full or partial spiral, cubic, polyhedron, substantially rod-like configuration, and the like. In addition to the foregoing, it is contemplated that, for the purposes of the present invention, shape configurations which exhibit a high ratio of greatest dimension / smallest dimension, such as needles, flakes or fibers, are contemplated. Optionally, conglomerates of gel-forming absorbent material particles may also be used to form the composite absorbent system 26. Particles for use herein are particles having an average size ranging from about 5 microns to about 1 mm. As used herein, the term " particle size " refers to the average diameter of the individual particles found.

According to specific aspects of the present invention, the gel-forming absorbent material particles may exhibit a modified absorbency under load (MAUL) value of at least about 20 g by absorbing absorbed liquid per g of absorbent material (g / g). Desirably, the superabsorbent material has a MAUL of at least about 24 g / g, and even more desirably that said material has a MAUL of up to about 30 g / g or greater. The MAUL value can be determined using the test method for measuring modified absorbency under load, which is described in detail in the "Calculation Methods and Test Procedures" section below in the description of the present invention.

427 / B

The mixture of hydrophilic fibers and particles of the highly absorbent material may be configured to have an average basis weight ranging from about 400 to about 900 g / m ² in the overall configuration of the absorbent core 30 of the composite absorbent system. According to some aspects of the present invention, to provide the desired performance of the absorbent article, the average basis weight of said composition is in the range of about 500 to about 800 g / m ² , and preferably in the range of about 550 to about 750 g / m ² .

According to specific aspects of the present invention, the highly absorbent material may comprise a superabsorbent nonwoven material. A superabsorbent nonwoven material is a nonwoven consisting solely of the respective superabsorbent fibrous material and / or a mixture of superabsorbent fibrous material and other materials. The superabsorbent nonwoven material exhibits a high liquid retention capacity for immersion in liquid, especially immersion in 0.9% saline, at a liquid volume collection rate of at least about 10 g by absorbing the absorbed liquid per g of absorbent material (g / g). Alternatively, in order to provide improved performance characteristics, the liquid volume collection is at least about 20 g / g, and optionally at least about 30 g / g. The superabsorbent nonwoven material is selectively configured to promote and enhance fluid aspiration, fluid retention, fluid distribution, or some combination of these functions. Especially when the superabsorbent nonwoven material is incorporated into the absorbent article having a multilayer absorbent structure in the form of a separate layer or separate component, the superabsorbent nonwoven material may be designed to perform a specific function or group of such functions.

In order to limit the unwanted displacement of the highly absorbent material contained therein, the absorbent article may comprise a composite absorbent system 26 provided with an outer sheath, for example, a wrap layer 28 that is conveniently positioned, as desired, in adjacent configuration k around the entire absorbent core 30. an absorbent core or around one or more selected composite components

427 / B absorption system. In addition, said wrapping layer may be coupled to the composite absorbent system and various other components of the absorbent article. The wrapper 28 is preferably a layer of absorbent material that covers all the lateral and outer surfaces of the composite absorbent system, and preferably surrounds substantially all peripheral edges of the absorbent system, thereby forming a substantially complete outer shell thereof. Alternatively, the sheath 28 may provide an absorbent sheath that covers the vast majority of the lateral and outer surfaces of the absorbent core and substantially surrounds only its lateral side edges. Accordingly, both the linear and inwardly curved portions of the lateral side edges must be surrounded and closed around the composite absorbent system. In such an arrangement, however, the leading end edges of the wrapper may not be completely enclosed about the leading end edges of the absorbent system located in the regions of the waistband of the absorbent article.

For example, the wrapper 28 as a whole or at least the skin-facing portion of the wrapper may comprise a meltblown web of meltblown fibers such as polypropylene fibers. According to another example, the absorbent cover layer 28 may comprise a low void pulp web, for example a thin paper layer consisting of a 50:50 mixture of soft / hard cellulosic fibers.

The absorbent cover layer 28 may be comprised of a plurality of subcomponents comprising a separate body-facing cover and a separate outwardly arranged outer liner cover layer, each extending over all or at least some peripheral edges of the absorbent core 30. Such a container configuration For example, the backsheet in the diaper illustrated in the accompanying drawing may be configured such that, in order to increase the opacity and strength of the rear edge regions of the diaper, the wrapper may be configured to provide substantially complete closure and sealing. extends over a greater distance over the peripheral edges of the absorbent core. In the exemplary embodiment shown, the inner and outer partial layers are formed

427 / B of the absorbent cover layer 28 extend at least about 12.7 mm (1/2 inch) across the peripheral edges of the absorbent core to provide an outwardly extending weave by which the peripheral edges of the inner body facing portion of the absorbent cover layer can be either fully or at least partially connected to the peripheral edges of the outer portion of the absorbent cover layer.

The inner body-facing sub-layer and the outer garment-facing sub-layer of the skin layer 28 may consist of essentially the same or vice versa, of different materials. The outer partial layer of the skin layer may consist, for example, of a material with a relatively lower basis weight and a relatively high void density, such as a high wet strength thin cellulose layer, formed from softened technical cellulose. The inner body-facing partial layer of the cover layer may further comprise one of the materials referred to in relation to the cover layer, which exhibits a relatively low voidiness. The low void material, when used to form the inner subcoat of the casing layer, is capable of better eliminating the undesirable migration of superabsorbent material particles to the skin of the user, while a high void material and a lower basis weight for the outer subcoat of the casing layer can help reduce manufacturing costs. .

Referring to FIG. 7, 8 and 9, further embodiments of the absorbent core of the present invention may include a sub-element comprising particles 102 of superabsorbent material that are operably maintained between two layers 100 of a liquid-permeable material, such as paper pulp, open cell foam, porous foil, woven fabric, nonwoven fabric and the like, as well as combinations thereof. According to certain specific aspects of the present invention, the lower layer portion 50 may consist of a laminate having superabsorbent material particles sandwiched between two layers of retention paper pulp and sealed by waterproof fastening means. Examples of such absorbent core configurations are described in U.S. Pat. No. 5,593,399 to R. Tanzer et al., Entitled "Absorbent article comprising superabsorbent material positioned conveniently

427 / B in separate longitudinal pouch cartridges arranged in a chosen configuration, published February 14, 1997 (see verified annotation and brief content No. 10,902.1), the entire disclosure of which is hereby incorporated by reference into the present invention to its nature.

Referring again to FIG. 1 and 2, the diaper 20 may further include an impact buffering layer 84 in addition to the aforementioned components to assist in retarding, alleviating, and dispersing the impact of body fluid so that they can be directed into the retention and storage portion of the absorbent article absorbent article. Said compensating layer 84 may be positioned, for example, on an inwardly facing surface facing the skin of the user facing topsheet 24. In the exemplary diaper embodiment shown, the compensating layer 84 may be positioned adjacent to the outer surface of the absorbent structure. Accordingly, the alignment layer 84 is sandwiched between the topsheet 24 and the absorbent core 30. Examples of suitable alignment layers 84 are useful, for example, in U.S. Patent Application Ser. 206,986 by C. Ellis and D. Bishop, entitled "Nonwoven Fiber Layer, for Personal Protective Hygiene Absorbents and Similar Preparations", filed March 4, 1994 (see Verified Annotation and Concise Content No. 11,256 ), which was published as a US patent No. 5,486,166 and U.S. Pat. 206,069, by C. Ellis and R. Everett, entitled "Enhanced Leveling Component with Regulatory Capabilities, Made of Nonwoven Fiber Fabric, for Personal Protective Hygiene Absorbents and Similar Preparations, filed March 4, 1994" No. 11,387), which was published as a US patent No. 5,490,846, the entire disclosure of which is hereby incorporated by reference into the present invention in accordance with its spirit.

427 / B

According to specific aspects of the present invention and with reference to FIG. 1 and 2, the absorbent diaper 20 may comprise a composite absorbent system that includes a selected amount of two or more primary layer portions. The multilayer absorbent core 30 includes, for example, a first layer portion 48 and at least a second layer portion 50 in the configuration shown.

The first layer portion 48 of the exemplary embodiment provides, relatively taken, an upper layer portion that is disposed on the skin-facing side of the absorbent core 30 and is relatively proximate to the topsheet 24. The shown second layer portion 50 provides, relatively a lower layer portion, which is disposed on the outwardly facing, garment facing side of the absorbent core and is located relatively proximate to the lower backsheet 22.

Upon request according to one aspect of the present invention, the individual components contained in the different layer portions of the absorbent system, for example the layer portions 48 and 50, may comprise a mixture or other matrix of high bulk fibrous materials. High bulk fibrous materials are those which provide improved bulk stability and / or deformation recovery (restoration). Such high bulk fibrous materials are particularly capable of providing good wet bulk stability and / or recovery after wet deformation when incorporated into materials that are subjected to wetting or liquid treatment. Examples of suitable high volume fibrous materials useful herein include synthetic thermoplastic fibrous materials, synthetic materials consisting of natural polymers, such as pulp and natural fibrous materials, as well as combinations thereof. The resistance of fibrous materials consisting of natural polymers can be increased by chemical crosslinking and / or by twisting fibrous materials into loops and / or by crimping these materials.

High bulk fibrous materials have the ability to exhibit low density in both wet and dry conditions, thereby increasing throughput and thickness, resulting in increased flow conductivity. High-volume wood pulp-based fibrous materials can be obtained by various means

427 / B processing techniques, for example by chemical and / or mechanical modification of fibrous pulp. Examples of suitable high-volume materials useful for the purpose include mercerized fibrous materials, crosslinked technical pulp in the form of tufts and the like, as well as combinations thereof.

According to a further aspect of the present invention, the individual components contained in the various layered portions of the absorbent system, for example the layered portions 48 and / or 50, may consist of a mixture or other matrix of high bulk fibrous materials and a controlled proportion of superabsorbent material. Such a controlled content superabsorbent material is a material, for example, a superabsorbent polymerization material that has a minimum modified absorbency under load (MAUL) value of at least about 20 g / g.

According to another aspect of the present invention, the controlled content superabsorbent material in the structure may exhibit a specific uptake rate (time characteristic), expressed as a Tau (τ) value, for example, wherein said Tau (τ) value is at least about 0.4 min. The superabsorbent material used is required to have a Tau of at least about 1 minute, which Tau may be at least about 2 minutes to provide improved performance. According to other requirements of the present invention, the size of said Tau may be up to about 40 minutes. and more. According to further aspects of the present invention, a selected combination of superabsorbent materials, in which at least one selected pair of different superabsorbent materials, is configured to provide a ratio of Tau values of the materials, may preferably be incorporated in the absorbent core, particularly in the various layer portions of the absorbent core. Optionally, to provide further functional improvement, the ratio of Tau values may be up to about 5: 1, or greater. Desirably, the superabsorbent material exhibiting a relatively higher Tau value is positioned relatively closer to the skin of the wearer facing the absorbent core surface. A suitable test procedure for determining the Tau value of each absorbent structure of the absorbent material used is described in detail in the Chapter.

427 / B "Zero Load Inundation Absorbency (FAUZL)", listed in the "Calculation Methods and Test Procedures" section.

A specific controlled content superabsorbent material in the structure useful for this purpose may be a particulate superabsorbent material whose individual particles are impregnated with a hydrophobic coating to provide a predetermined delay in the absorption of water-based liquids into the particle volume. Thus, the superabsorbent material used may be, for example, a particulate superabsorbent material with surface-coated particles. These particles have an absorbent core formed by a partial sodium salt of cross-linked polypropionic acid (prepared using the process described in U.S. Patent No. 5,629,377), and the core is coated with a hydrophobic silicone elastomer. A characteristic superabsorbent material with a controlled content ratio in a structure of this type is commercially available from the Dow Chemical Company, with sales offices in Midland, Michigan, U.S.A.

In an alternative embodiment, the controlled content superabsorbent material in the structure may be formed with a relatively large particle size, which implies that such particles exhibit a low surface area to volume ratio and, as a result, achieve the desired rate of absorption. Furthermore, the particles of superabsorbent material having a controlled content content in the structure may have a substantially spherical or other three-dimensional shape configuration that effectively provides the desired low surface area to volume ratio and the desired residence time.

Moreover, in addition to the above, the quantitative chemical composition of the superabsorbent polymerization material can be modified to achieve the desired residence time with a residence time. Thus, for example, an anionic polyelectrolyte, which is reciprocally crosslinked with a multivalent metal cation, may be incorporated into the controlled content superabsorbent material in the structure. A water-soluble complexing agent can be used to restore the crosslinking to its original state.

427 / B

Alternatively, the controlled content superabsorbent material in the structure may be encapsulated or otherwise coated to provide effective liquid diffusion into the superabsorbent material particles or to repel the liquid so as to achieve the desired uptake rate with residence time. . Said sheathing or surface treatment may be either elastically conformable or non-conformable and further may be either hydrophobic or hydrophilic. The described coatings may be designed to be controlled erodible, dissolvable or disintegrable in order to achieve the desired absorbency characteristics. Optionally, the rate of uptake can be limited and / or controlled by modifying the rate of neutralization of the selected superabsorbent material or by modifying or otherwise controlling the chemical mechanism applied to effect neutralization of the selected superabsorbent material.

Other aspects of determining the ingestion of superabsorbent material under load (AUL) are described in detail in U.S. Pat. 5,550,189, entitled "Modified Polysaccharides with Enhanced Absorbent Properties, and Methods for Their Preparation," by J. Qin et al., Issued Aug. 26, 1996; and U.S. patent application Ser. No. 621,390, entitled " Absorbent Composite Material ", by M. Melius et al., Filed March 25, 1996 (see Verified Annotation and Brief Content No. 10,838.2). The full description of the documents cited above is hereby incorporated by reference into the present invention in accordance with its spirit.

Referring to FIG. 2 and 2A illustrate an exemplary embodiment of a first layer portion 48 that may include a controlled content superabsorbent material and high bulk fibrous wood pulp or other woven or nonwoven fibrous materials having a pore size distribution (voidiness) that as a result allows for rapid absorbing the acting liquid while maintaining the liquid in the volume of absorbent material until the liquid is capable of absorbing relatively outwardly, closer to the user ' s laundry, the layer portion or layers of the absorbent structure. The respective components may be arranged in the first layer portion 48 so as to substantially overlap the predetermined receiving zone 52 of the absorbent article, i. zone

427 / B, which introduces acting fluids, such as urine or other bodily fluids, into the absorbent structure. Accordingly, the suction layer portion of the absorbent core can in fact be determined by the first layer portion 48. Said layer portion 48 may have a rectangular rectangular, general quadrilateral or any other irregular shape configuration, but it is desirable that the layer portion, by its size, does not extend below the layer portion arranged thereon, for example the second layer portion 50. According to the desired aspects of the present invention. According to the invention, the first layer portion will be smaller than below it, relative to the exterior relative to the arrangement of the absorbent structure, the second layer portion will be arranged.

For example, the first primary layer portion may substantially extend as a whole in a zone that begins at a transverse direction of the extending line, spaced approximately 7% of the length of the absorbent core inwardly from its foremost edge and ending at a transverse direction a direction extending at approximately 62% of the length of the absorbent core inwardly from its foremost edge. In addition, the longitudinally extending lateral edges of the first primary layer portion may substantially conform to corresponding lateral edges of the second primary layer portion.

Other configurations of an alternative configuration of the absorbent structure are shown in FIG. 3-6. According to particular specific aspects of the present invention, the layer portion 48 may comprise a composite absorbent system comprising a plurality of partial layer portions.

Fig. 3 and 3A illustrate, for example, the structure of the absorbent core, as seen from above, provided with a first topsheet 48 extending over a central region of the total extent of the absorbent core 30 and a second bottomsheet 50 extending over substantially the entire overall range of this absorbent core. The second layer portion 50 exhibits a selectively distributed, uneven zonal basis weight with a relatively higher basis weight at its opposed end portions in the longitudinal direction, thereby providing an inverted zonal distribution of the lower layer portion in the longitudinal direction.

427 / B direction, especially in its receiving zone. The determined central zone of the second layer portion 50 may additionally have a basis weight that is less than the basis weight adjacent thereto and this layer portion overlapping the first layer portion 48, thereby providing a reverse zonal thickness in the receiving zone. The lateral end edges of the topsheet 48 in the transverse direction, at least in the crotch region of the absorbent core 30, border with corresponding lateral end edges of the second ply 50. The front end edges of the first ply 48 in the longitudinal direction are relative to the corresponding front end edges of the second ply 50 offset to the inside.

Fig. 4 and 4A illustrate, by way of example, the structure of the absorbent core provided with a first, topsheet 48 that spans the entire range of the front and rear panels, respectively. a first section by a second, lower layer portion 50 and only a portion of the rear and rear layers respectively; a second section of the lower layer portion. The lateral end edges in the transverse direction and at least a portion of the front end edges in the longitudinal direction of the first layer portion 48 substantially border with the corresponding lateral end edges in the transverse direction and at least a portion of the front end edges in the longitudinal direction of the second layer portion 50. In the example embodiment one end face edge of the first layer portion 48 in the longitudinal direction disposed relative to the corresponding end face edge of the second layer portion 50 in an inwardly offset manner.

Fig. 5 and 5A illustrate an absorbent core structure having a first topsheet 48 and a second bottomsheet 50 that are arranged such that the topsheet 48 overlaps the bottomsheet 50 in its entirety. Although in the embodiment shown, the first, topsheet 48 and second, bottomsheet 50 have substantially the same thickness and basis weight, in an alternative embodiment, the firstsheet 48 and the secondsheet 50 may also have a different thickness and different base weight. weight, as well as other structural differences.

427 / B

Fig. 6 illustrates, by way of example, a top view of another absorbent core arrangement whose first, topsheet 48 has a smaller, narrower dimension than the dimensions of the second, lowersheet 50, in both the transverse direction and a smaller, shorter dimension in the longitudinal direction. direction. In the embodiment shown, the outer periphery of the end edges of the first sheet portion 48, substantially as a whole, is spaced apart from the entire outer periphery of the end edges of the second sheet portion 50 inwardly.

In various embodiments of the present invention, in order to control the speed, respectively, the speed and the speed of the motor can be controlled. liquid retention intensity in the various layered portions of the absorbent system configured superabsorbent material with a controlled proportion of content in the structure. The absorbent structure can provide controlled control of the liquid retention rate in its volume only by the presence of a controlled content superabsorbent material (SAM) or by combining the superabsorbent material with other materials to provide an embodiment of the controlled content superabsorbent composite material. The superabsorbent material or superabsorbent composite material with controlled content in the structure may be used as the absorbent layer portion in the layer portions of the layered composite absorbent system, especially when the superabsorbent material with controlled content in the structure (SAM) is superabsorbent composite with controlled content. in the structure, it is selectively configured to promote preferential saturation of one or more additional layer portions in the multilayer absorbent system during appropriate functional use conditions. By using a combination of high bulk fibrous materials and a superabsorbent material with a controlled amount of content in the structure, the saturation in the first layer portion 48 can be maintained at a value less than the saturation level in the other absorbent layer portions resulting from the fact that the first layer portion 48 in this state, it has a higher void volume and permeability and provides the desired levels of flow conductivity values.

427 / B

The composite material, consisting of a high-volume fibrous material, in particular fibrous pulp, and a superabsorbent material, can also be modified by introducing a stabilizing agent into the material. Said stabilization is used to ensure that changes in the structure of the particulate material or in the composite structure of the materials are maintained or minimized during exposure to external or internal forces. The structure of the stabilizing mechanism may be useful for any of the layered portions arranged in the layered layered portion comprising the structure by assisting in maintaining the layered portion of the absorbent structure in the desired condition while exposed to the forces applied to the structure under functional application conditions as part of the absorbent article comprising the multilayer absorbent article. . This helps to maintain and perform the intended functional operation of the layer portion, namely, aspirating the liquid (forming a void volume), retaining the liquid, distributing the liquid, or some combination of these three functions. For the purpose of stabilizing the absorbent structure, it is possible to use various types of suitable and suitable technological processes. Corresponding stabilization can be carried out, for example, by chemical stabilization using stabilizing agents, for example Kymene reagents or other crosslinking agents, or by introducing thermoplastic binder fiber materials or the like.

According to various aspects of the present invention, the topsheet 48 may consist of woven or nonwoven fibrous material. As with the foregoing aspects of the present invention, these materials can be configured to provide maximum void volume and permeability while maintaining sufficient capillary stress to ensure controlled fluid displacement and overall elimination of unwanted leakage. For example, nonwoven fibrous materials may be incorporated into the absorbent cores of the present invention as functional components of the topsheet 48. Particular examples of such fibrous materials are carded webs or webs, which may be configured to provide adequate throughput and capillary capillarity. Based on a selection of specific properties

427 / B of a staple synthetic staple, it is possible to provide a composite structure in which the bottom layer portion 50 is preferably saturated. This effect can be achieved either by physically structuring the top layer portion, by controlled surface property chemistry, or a combination thereof. The voidiness of the fibrous structures can be determined by specific fibrous materials or by pre-selected fiber sizes. By selecting the structure of the fibrous material, the capillary capillarity of the fibrous material can also be influenced.

Suitable carded structures for use herein are formed from different types of fibrous materials and a variety of fiber sizes. These fibers may be fibers made of synthetic or naturally occurring materials. It is desirable that the fibrous materials intended to form the first layer portion 48 exhibit high wettability, and natural pulp materials such as silk or cotton may be used for this purpose. Synthetic fibrous materials, such as polyester and polyamide, while providing limited wettability, can be increased by hydrophilic surface treatment or finishing. Although fibers with diameters ranging over a relatively wide range are present in carded nonwoven webs, the desired structure should include fibers with an equivalent diameter of less than 25 microns. The shear bonded fibrous materials intended to form the first layer portion 48 may be manufactured with a basis weight ranging from 50 to 200 grams per square meter (g / cm ² ) and a density of about 0.03 g / cm ³ or less. The density of the fibrous material will in fact depend upon the bonding or stabilization procedures used to process it into the web or web.

The carded web can be stabilized using a variety of technological techniques. In some instances, the incorporation of thermoplastic staple synthetic staple is used such that the formed structure can be bonded by applying heat and pressure. By suitable application of heat and pressure in the thermal bonding, the resulting structure can be obtained, is appropriately stabilized and exhibits a precisely determined permeability and capillary capillarity. Further, the structures may be formed from carded bound

427 / B fiber materials stabilized by the use of synthetic resins or binder adhesives. Again, as in the above uses, the selection of the type of synthetic resin or binder adhesive, the amount added, and the method of curing thereof will facilitate the control of the final properties of the fibrous structure that provide adequate permeability and capillary capillarity. Wettability can be influenced by the appropriate choice of the synthetic resin system for the bonding. In addition, structures formed from carding bound fibrous materials can be stabilized mechanically using water, needling fibers, air, or other fiber entanglement means. Again, these technological processes can be controlled in a manner that ensures the desired physical properties of the material.

According to specific aspects of the present invention, a web or nonwoven fabric having similar properties to the materials described above may be incorporated into the absorbent structure under the nozzle. According to other aspects, said material may also include a selected fiber size zone distribution, basis weight, or other characteristics required to provide the desired functional properties. In addition to carded bonded and spunbonded fibrous webs and webs, fibrous materials may also be used for blowing air.

The individual components of the materials contained in the first layer portion 48 may be present in an amount, with a basis weight, density, and the like, as described below. The characteristic basis weights of the absorbent core region located in the front half of the absorbent article can range from about 750 to about 905 g / cm ² . The first layer portion 48 may provide about 25 to 75% of the total basis weight of the composite system in those regions in which the layer portion is present relative to the above. This proportion is highly dependent on the materials used and their relative performance and efficiency. Materials in which superabsorbent materials are used in combination with fibrous fluff pulp and / or some staple synthetic staple fibers will typically exhibit an initial density in the range of about 0.1 to about 0.3 g / cm ³ . Synthetic base materials, carded or spunbonded fabrics or webs will typically exhibit

427 / B density ranging from about 0.015 to about 0.3 g / cm ³ , with a density of about 0.2 g / cm ³ being desired. Fabrics made of synthetic fibers will exhibit a characteristic fiber size (yarn fineness) of less than 3 denier, preferably a fiber size ranging from 1 to 2 denier, and will be treated to have a low wetting angle with water even after multiple wetting. Desirably, said treatment does not reduce the surface tension of the liquid passing through the fibrous web.

In addition, other nonwoven fibrous materials and structures may be used to form the topsheet portion of the absorbent system of the present invention. A suitable balance of wicking and capillary capillarity of the lower layer may provide preferential saturation of the lower layer even after multiple liquid impact. Similarly, it is predictable to use a different bottom layer portion, one that exhibits superior distribution capabilities. The abovementioned abilities may assist in the desorption of the nonwoven fabric topsheet, which may result in improved performance of the absorbent system after the second impact of the liquid.

According to desirable aspects of the present invention, the absorbent structure may have a liquid wicking value that is greater than about 36%. According to other aspects of the present invention, it may have a wicking value greater than about 16%, and a flow conductivity value greater than about 7 x ^{10 6} cm ³ . According to still further aspects of the present invention, it may exhibit a combined conductivity / absorbency value (C) of at least ¹⁴ x ^{10 6} cm ³ .

The desired combination of flow conductivity and liquid wicking properties can provide an advantageous balance of controlled fluid control characteristics. In particular, said merger can provide the desired balance of rapid fluid intake together with rapid transfer of absorbed liquid from the intake receiving zone to the more distal regions of the absorbent system. The commonly used absorption systems are not the desired combination

427 / B of the relevant characteristics capable of providing. This is mainly because absorption systems that provide the desired rapid liquid suction are unable to provide a velocity-sufficient transfer of absorbed liquid from the intake receiving zone to their more distant regions, and, in contrast, absorption systems that exhibit rapid displacement capability. absorbed liquid from the intake receiving zone towards their more distal regions, they are not able to provide a sufficiently rapid suction of the liquid. This may result in premature, excessive saturation of the absorption zone of the absorbent system or undesirable excess liquid accumulation on the surface of the absorbent article against the skin of the wearer.

According to specific aspects of the present invention, the first layer portion 48 may be an upper skin-facing layer that may typically extend across the central zone of the overall absorbent core range, but may optionally extend across the entire absorbent core range. Typically, the topsheet is a layer that is optimized to perform suction and may or may not provide the desired liquid wicking and liquid performance levels. The first layer portion may typically have a minimum basis weight of not less than about 100 g / cm ² , and preferably may have a basis weight of not less than about 300 g / cm ² . According to further aspects of the present invention, the first layer portion may have a maximum basis weight not greater than about 700 g / cm ² , and preferably may have a basis weight not greater than about 600 g / cm ² .

Referring to FIG. 3 and 3A, the first layer portion 48 typically comprises a minimum amount of fibrous material that is not less than about 50% by weight, and preferably includes an amount of fibrous material that is not less than about 60% by weight. According to further aspects of the present invention, the first layer portion may typically comprise a maximum amount of fibrous material not greater than about 80% by weight, and preferably may comprise an amount of fibrous material not greater than about 70% by weight. The fibrous material may be a natural or synthetic material. Said fibrous material

The 427 / B may have a minimum fiber size, especially a fiber diameter, of at least about 4 microns (pm), and preferably has a fiber size of at least about 10 µm. According to other aspects of the present invention, the fibrous material may have a maximum fiber size of not more than about 20 µm, and preferably has a fiber size of not more than about 15 µm.

The first layer portion 48 may further comprise a minimum amount of superabsorbent material that is not less than about 20% by weight, and preferably it may comprise an amount of superabsorbent material that is not less than about 30% by weight. According to further aspects of the present invention, the first layer portion may comprise a maximum amount of superabsorbent material that is not greater than about 50% by weight, and preferably may comprise an amount of superabsorbent material that is not greater than about 40% by weight. Said superabsorbent material may have a minimum dry particle size of not less than about 110 µm, preferably having a dry particle size of not less than about 300 µm. According to other aspects of the present invention, the superabsorbent material may have a maximum dry particle size of not more than about 1000 µm, and preferably may have a dry particle size of not more than about 700 microns. The superabsorbent material may further have a MAUL of at least about 20 g / g, and preferably may have a MAUL of at least about 25 g / g. In addition, in addition to providing improved material utilization, the MAUL may be up to about 30 g / g or greater. According to still other aspects of the present invention, the superabsorbent material may have a minimum Tau value of at least about 0.8 min. and a maximum Tau of up to about 40 min.

Typically, the first layer portion 48 may have a minimum average density of at least about 0.03 g / cm ³ , preferably having an average density of at least about 0.05 g / cm ³ . According to further aspects of the present invention, the first layer portion may have a maximum average density not greater than about 0.4 g / cm ³ , and preferably may have an average density not greater than about 0.2 g / cm ³ . The first layer portion includes any paper layers that are used to hold materials placed in the first layer portion together or are

427 / B acting as carrier. For example, some of these paper layers may be used to maintain sandwiched superabsorbent material between these layers.

Various embodiments of the present invention may include any high performance suction material in selected layers of the absorbent structure. Examples of suitable suction materials may include those detailed in U.S. patent application Ser. No. 754,414 entitled " Multipurpose Absorbent Material & Products Made thereof, " by R. Anderson et al., Filed Nov. 22, 1996 (cf. Verified Annotation and Brief Content No. 12,442) and Provisional (“Caveat”) Patent Application US No. 068,534 entitled "Pulp and Superabsorbent Composite for Improving Suction Efficiency" by L. H. Sawyer et al., Filed Dec. 23, 1997 (see Verified Annotation and Brief Content No. 13,041). The complete descriptions of the above documents are hereby incorporated by reference into the present invention in a sense consistent with its spirit.

Referring to FIG. 3 and 3A, the second layer portion 50 may comprise a blend or matrix of a hydrophilic fibrous material, such as wood pulp in fibrous form, and a selected amount of gel-forming superabsorbent material, such that the second layer portion consists for example of Coosa 1654 wood pulp and superabsorbent type Stockhausen Favor 880. These materials will be mixed or otherwise combined in a conventional manner such that about 20 to 80 wt. of the composite structure formed are particles of superabsorbent material. In order to ensure increased activity, this material may be processed using the appropriate modification. Such modifications may include the use of modified beech fibers to achieve improved liquid distribution efficiency, or the use of a stabilization technology to provide structural reinforcement and achieve improved liquid wicking. Possible, suitable and useful stabilization methods include, but are not limited to, selectable range, the use of a binder material, such as a Kymene type or some other cross-linking agent, or introducing into the structure to be subjected to thermally activatable binder fiber materials.

427 / B

Structure stabilization is a technological process that is used to consolidate, ensure maintenance, or minimize the occurrence of changes in the structure of a material or in the structure of a composite blend of materials while exposed to external or internal forces. Various techniques may be used to effect stabilization of the structure, such as the introduction of thermoplastic binder fiber materials, chemical stabilization using stabilizing agents (e.g., Kymene-type reagent) or other crosslinking agents, and the like, as well as combinations thereof.

Any desired material that is functionally configured to exhibit the ability to provide improved distribution of the acting fluid from the acquisition zone may provide the desired functionality and efficacy. Such materials may consist of a laminated material comprising superabsorbent material particles and at least one fibrous sheet or web, configured in particular to exhibit improved inundation absorbency efficacy upon impacting fluid. Suitable arrangements of the second sheet portion 50 may include, but are not limited to, selectable range, laminates consisting of particulate or fibrous superabsorbent sheets or webs with pulp-based fibrous materials, or any other stabilized fibrous webs. Other suitable fibrous materials may include wet spun paper pulp, airborne fibrous materials, as well as the types of fibrous materials used to form the first layer portion 48. Other types of materials that are useful to provide the desired improved performance are laminated materials consisting of: particles of superabsorbent materials or fibrous superabsorbent sheets and of open-cell wettable foam.

427 / B

The second layer portion 50 may be disposed within the absorbent structure in a variety of configurations suitable for the purpose described. For example, the second layer portion 50 may be in the form of a separate absorbent pad that is conveniently positioned in an immediately adjacent configuration to the first layer portion 48. The second layer portion 50 is preferably arranged in substantially direct contact with the first layer portion 48; alternatively, however, the second layer portion 50 may be spaced from the first layer portion 48 by means of one or more layered portions of selected material that are sandwiched between said first and second layer portions 48 and 50. According to specific aspects of the present invention, the second layer portion 50 configured to ensure and allow maximum utilization of the absorbent material to process the incoming liquid while maintaining the comfort properties of the absorbent article.

According to further aspects of the present invention, the second primary layer portion may have a longitudinal extent that is greater than the longitudinal range of said first primary layer portion. Additionally, the second primary layer portion may have a transverse extent that substantially coincides with the transverse range of said first primary layer portion. Alternative embodiments of the present invention may include a second primary layer portion having a transverse range that is less than the transverse range of said first primary layer portion. In this state, for example, the transverse extent of at least a portion of the second primary layer portion may not be less than about 30% of the transverse extent of the corresponding portion of the second primary layer portion of the adjacent portion of the first primary layer portion. Other embodiments may include a second such primary layer portion that has a transverse range greater than the transverse range of the first primary layer portion. In this state, for example, the transverse extent of at least a portion of the first primary layer portion may not be less than about 30% of the transverse extent of the corresponding portion of the first primary layer portion of the adjacent portion of the second primary layer portion.

Referring to FIG. 3 and 3A, the individual components of the materials contained in the second primary sheet portion 50 may be present in different effective amounts, with different basis weights, with different densities, and the like.

427 / B

For example, the second primary layer portion 50 may have a selected unevenly distributed basis weight. In addition, the second layer portion may comprise 25 to 100% of the total basis weight of the composite structure of the absorbent core at any selected position, typically having a density ranging from about 0.1 to about 0.3 g / cm ³ . According to still further aspects of the present invention, the second layer portion may have a plurality, two or more, of the partial layer portions, each of the partial layer portions having a selected combination of physical and functional characteristics.

According to specific aspects of the present invention, at least one of said layer portions of the absorbent core 30 is a liquid distribution layer capable of providing a liquid wicking value of not less than about 16%. In addition, the distribution layer has a circumferential boundary and a surface area that extends across and outside the designated receiving zone 52 of the composite absorbent system.

Said distribution layer may advantageously provide certain specifically important functions. The first function involves retention retention and displacement of the acting fluid beyond the receiving zone, and the second function is to provide a sufficiently short-term (within the duration of the impact) duration of the inundation gushing superabsorbent structure causing the void volume deficit associated with absorbent articles in a low thickness design. The structural components of this layer portion include the content of the superabsorbent polymerization material (SAP), the basis weights of the individual components, and their density. Examples of materials having a high effective liquid wicking capacity are described in detail in U.S. Pat. No. 5,350,370, entitled " Absorbent Composite Materials with High Liquid Absorption ", issued September 27, 1995 to D. M. Jackson et al., The entire disclosure of which is hereby incorporated by reference in its entirety.

427 / B

The second layer portion 50 may provide a backsheet and typically may extend over the total surface area of the absorbent core 30 as a whole. This second layer portion 50 is typically designed to provide liquid distribution or absorbency in the absorbent core volume and, therefore, will typically extend over and outside the end peripheral edges of the surface area overlaid by the first layer portion 48. In the acquisition zone section 52, the second layer portion 50 may typically have a basis weight of not less than about 100 g / m ² , and preferably may have a basis weight of not less than about 200 g / m ² . According to other aspects of the present invention, the acquisition zone of the second layer portion 50 may have a basis weight not greater than about 700 g / m ² , and preferably may have a basis weight not greater than about 250 g / m ² . In other, non-receiving portions outside and outside the receiving zone of the second layer portion 50, the second layer portion may typically have a basis weight of not less than about 300 g / m ² , and preferably may have a basis weight that is not is less than about 450 g / m ² . According to other aspects of the present invention, the other non-receiving portions outside and outside the receiving zone may typically have a basis weight of not more than about 800 g / m ² , preferably having a basis weight of not is greater than about 550 g / m ² .

The second sheet portion typically comprises an amount of fibrous material that is not less than about 50% by weight, and preferably includes an amount of fibrous material that is not less than about 60% by weight. According to further aspects of the present invention, the second layer portion may typically comprise an amount of fibrous material not greater than about 95% by weight, and preferably may comprise an amount of fibrous material not greater than about 80% by weight. The fibrous material may be both natural and synthetic. Said fibrous material may have a minimum fiber size, in particular a fiber diameter, of at least about 4 microns, preferably having a fiber size of at least about 10 microns. According to other aspects of the present invention, the fibrous material may have a maximum fiber size not greater than about 20

427 / B gm and preferably has a fiber size of not more than about 15 µm. In addition, the fibrous material may have a water contact angle of no more than about 70 °, and preferably may have a water contact angle of no more than about 50 °.

The second layer portion may further comprise an amount of superabsorbent material that is not less than about 5% by weight, and preferably it may comprise an amount of superabsorbent material that is not less than about 15% by weight. According to further aspects of the present invention, the first layer portion may comprise an amount of superabsorbent material that is not greater than about 50% by weight, and preferably may comprise an amount of superabsorbent material that is not greater than about 40% by weight. Said superabsorbent material may have a minimum dry particle size of not less than about 110 µm, preferably having a dry particle size of not less than about 300 µm. According to other aspects of the present invention, the superabsorbent material may have a maximum dry particle size of not more than about 1000 µm, and preferably may have a dry particle size of not more than about 700 µm. The superabsorbent material may further have a MAUL of not less than about 20 g / g, and preferably may have a MAUL of not less than 25 g / g. In addition, in addition to providing improved material utilization, the MAUL may be up to about 30 g / g or greater. According to still other aspects of the present invention, the superabsorbent material may have a Tau value of at least about 0.8 min, and preferably may have a Tau value of at least about 2 min.

Preferred embodiments of the present invention may include a second layer portion 50 having a liquid wicking value of at least about 36% and comprising a superabsorbent material having a Tau value of not less than about 0.4 min. Other preferred embodiments may include a second layer portion having a liquid wicking value of at least about 16% and comprising a superabsorbent material having a Tau value of not less than about 0.67 minutes.

427 / B

According to specific aspects of the present invention, the superabsorbent material contained in the first layer portion 48 is configured to have a Tau value that is twice the Tau value of the superabsorbent material contained in the second layer portion 50 (the ratio of Tau values is about 2: 1). Alternatively, to provide the desired characteristics, the ratio of Tau values may be at least about 2.5: 1 and optionally at least about 3: 1. According to further aspects of the present invention, the combination of superabsorbent materials comprised in the first and second layer portions may be configured to provide a Tau ratio of up to about 10: 1, alternatively the combination may be configured to exhibit a Tau ratio of up to about 40: 1 or more.

The second layer portion 50 may typically have a minimum average density of at least about 0.01 g / cm ³ , preferably having an average density of at least about 0.15 g / cm ³ . According to further aspects of the present invention, the second layer portion may have an average density of no more than about 0.3 g / cm ³ , and preferably may have an average density of no more than about 0.25 g / cm ^3. . According to specific aspects of the present invention, the average density may be about 0.2 g / cm ³ . The second layer portion includes any optional paper layers that are used to hold materials placed in the first layer portion together or act as carrier means. For example, some of these paper layers may be used to maintain sandwiched superabsorbent material between these layers.

Further detailed descriptions of various embodiments of the layered absorbent structure of the present invention are set forth in U.S. Pat. No. 09 / 096,652, entitled " Laminated Absorbent Structure ", by R. Everett et al., Filed June 12, 1998 (see Verified Annotation and Brief Content No. 13,505); in U.S. patent application Ser. No. 09 / 096,653, entitled "Laminated Absorbent Structure with a Heterogeneous Layer Part" by R. Everett et al., Filed Jun. 12, 1998 (cf. Verified Annotation and Brief Content No. 13,507), and U.S. Pat. 09 / 097,029, entitled "Laminated absorbent structure with a zonal basis weight heterogeneous

No. 427 / B of the layer portion, by R. Everett et al., Filed June 12, 1998 (see Verified Annotation and Brief Content No. 13,508). The complete descriptions of the above documents are hereby incorporated by reference into the present invention in a sense consistent with its spirit.

Referring again to FIG. 1, it can be recognized that elastic leg region elements 34 are disposed at the lateral end edges 110 of the diaper 20 and are arranged to contract and hold the diaper 20 on the user ' s legs. The leg region elastics 34 are fastened to the diaper 20 in an elastically clamped state so that they are under a certain tightening tension in the normal configuration and effectively contract against the diaper 20. The leg region elastics 34 may be secured in said elastically clamped condition by at least two methods, for example by first placing said leg region elastics 34 in an expanded state and then securing them to a diaper 20 which is in a normal non-contracted state. Alternatively, the diaper 20 may be retracted to a corresponding configuration, for example, by pleating or extinguishing, and the leg elastic elements 34 will be attached to the diaper in their relaxed or unstretched condition. Other means or mechanisms, such as a heat-shrinkable elastic material, may also be used to pleat or contract the absorbent article.

In the embodiment shown in FIG. 1, the leg elastic elements 34 extend substantially the entire length of the intermediate crotch region 42 of the diaper 20. Alternatively, the leg elastic elements 34 may extend over the entire length of the diaper 20 or any other length suitable to provide the elastic fit. the animal lines required for corresponding particular exterior designs and diaper shape.

The leg region elastics 34 may have substantially any configuration. Accordingly, for example, the width of the individual elastic members 34 may vary from 0.25 to 25 mm (0.01 to 1.0 inches) or more. The elastic members may consist of a single strip of elastic material, several

427 / B parallel or otherwise disposed strips of elastic material and / or may be applied in a straight line or curvilinear configuration. In the case of a non-parallel arrangement of the strips of elastic material, two or more strips in the elastic member may intersect or interconnect in other ways. The elastic members may be affixed to the diaper 20 by any of a variety of methods known in the art. Thus, the elastic members may be affixed to the diaper 20 by means of ultrasonic, thermal and pressure bonds using various bonding patterns or adhesive bonds, spray-applied or as segment or point networks of hot melt adhesive.

In specific embodiments of the present invention, the leg region elastic members 34 may comprise a backing layer to which an elastic member assembly comprising a plurality of individual elastic bands is attached to one another. The elastic bands may intersect with one another or otherwise interconnect and / or may be separated from each other. For example, the backing layer may be a film by caulking 0.002 cm thick unprocessed polypropylene material. For example, the elastic bands may consist of an elastomer of the trade name Lycra, marketed by DuPont, with a representative office in Wilmington, Delaware. Each elastic web exhibits a characteristic yarn weight fineness in the range of about 470 to about 1500 decitex, and preferably in the range of about 940 to about 1050 decitex. According to a specific embodiment of the present invention, three or four elastic leg bands may be used for each elasticized waistband region of the wearer's leg.

In addition, the leg region elastic elements 34 may generally be straight or optionally curved. For example, the curved elastic elements may be curved inwardly towards the longitudinal axis of the diaper. In specific embodiments, this curvature of the elastic elements need not be configured or arranged relative to the longitudinal axis of the diaper 20 symmetrically. The curved elastic members may be arched both inwardly and outwardly in the mirror arrangement, and the longitudinal placement of the centers of the elastic members may optionally be offset by a selected distance toward either the front or rear waistband portion of the diaper to provide the desired fit of the diaper user's body and ensuring her

427 / B of the desired appearance. According to specific embodiments of the present invention, the nearest center point (or apex) of the set of curved elastic members may be displaced towards the front or rear waistband portion of the diaper, and the outwardly folded, mirror-shaped portion may be positioned toward the front waistband portion.

According to an exemplary illustration, the diaper 20 may further comprise an elastic waist region member 32 disposed expediently at the longitudinal edges of either one, the front waist panel 38 or the back waist panel 40, or both. The elastic member 32 may consist of any suitable elastomeric material, such as an elastomeric sheet, an elastic foam, a plurality of elements composed of an elastic strip, an elastomeric sheet, or the like, as well as combinations thereof. A suitable design of the elastic waist region is described, for example, in U.S. Pat. No. 4,916,005 to Lippert et al., The entire disclosure of which is hereby incorporated by reference into the present invention in accordance with its spirit.

The diaper 20 may further comprise a pair of elasticized restraining restraint strips 82 that extend over its entire dimension in the length direction 86. The restraining restraint strips are typically disposed relative to the longitudinal axis of the wrapper, at their sides closer to the center away from the elastic members. 34 of the foot region and substantially symmetrically to each side. In the embodiment shown, each control restraint strip 82 has a substantially rigid edge section 81 and a substantially adjustable edge section 83 that are effectively elasticized to support tight fit and fit each control restraint strip to the contour of the user's body. Examples of suitable construction arrangements of regulatory retention strips are described in U.S. Pat. No. 4,704,116, issued November 3, 1987 to K. Enloe, the entire disclosure of which is hereby incorporated by reference in its entirety. Said control retention strips may consist of wettable or non-wettable material as desired. In addition, the material used to form the regulatory restraint strips may be substantially either liquid impermeable or

427 / B impermeable to liquids and at the same time permeable to gas and / or permeable to both liquids and gas. Other suitable arrangements of regulatory retention strips are described in U.S. Pat. No. 208,816 entitled "Absorbent Product with Enhanced Leveling Layer" by Everett et al., Filed Mar. 4, 1994 (cf. Verified Annotation and Brief Content No. 11,375), published as U.S. Pat. No. 5,562,650, the entire disclosure of which is hereby incorporated by reference into the present invention in accordance with its spirit.

In optional alternative embodiments of the present invention, the diaper 20 may include such elasticized restraint bands 82 as described in U.S. Patent No. 5,201,549. No. 4,735,646, K. Enloe, issued June 28, 1988; and U.S. patent application Ser. 560,525, entitled " Absorbent article with improved elastic edges and a regulatory restraint system ", by D. Laux et al., Filed Nov. 18, 1995 (see Verified Annotation and Brief Content No. 11,091), the entire descriptions of which are hereby incorporated into of the present invention in the sense corresponding to its nature. The strip strips, like the control retention strips 82, may consist of a wettable or non-wettable material. Said strip band material may be substantially either liquid impermeable or impermeable and gas permeable and / or permeable to both liquid and gas.

For the purpose of providing a reclosable fastening system, the diaper 20 may include a fastening suction section 78 (see FIG. 2) which constitutes a functional receiving area for receiving a releasable fastening by fastening straps 44. In specific embodiments of the present invention, the fastening suction section is arranged on the outer surface. and preferably disposed on the front waistband portion 38 of the diaper. The fastening mechanism between said suction section and the fastening strips 44 may be adhesive, cohesive or mechanical means, as well as combinations thereof. In a configuration with a releasable, engaging functional fastening system, the first functional fastener component may be disposed on the fastening suction section 78 and the second cooperating functional fastener component disposed on the fastening strip 44. For example, in use

427 / B of the hook and loop fastening system, the hook material portion 46 may be effectively coupled to the fastening strap 44 and the eyelet material portion 80 may be secured to the fastening suction section 78. Alternatively, the eyelet material may be operatively coupled to the fastening tab 44 and fastening The hook material 46 may be attached to the fastening suction section 78.

In various embodiments of the present invention, the fastening strip 44 may conveniently be disposed on either the side end region 116, the side end region 118, or both, either of the front waist panel 38, the rear waist panel 40, or both. In addition, a lower backsheet 22 may be provided on the outer surface thereof by the designated fastening suction section 78.

Referring to FIG. 1, the diaper may comprise, for example, a side panel system 90. In specific arrangements, each of the side panels 90 extends transversely from opposed side ends of at least one waistband panel portion 22, for example, such as the backband panel 40 shown, for example. to provide side end portions of the absorbent article. In addition, each of the side panels 90 may span a space extending substantially between the transversely extending waist end edge 106 and the diaper region in which the leg openings are formed. For example, the diaper 20 has a side pair of opposed leg openings formed by respective intermediate sections of the pair shown in the longitudinally extending side end edges 110 (see FIG. 1). Each panel may span a longitudinal distance of at least about 4 cm, optionally span a longitudinal distance of at least about 5 cm, and alternatively span a distance of at least about 6 cm, to provide an improved efficient fit.

427 / B

In various embodiments of the present invention, the side panels 90 may be integrally formed with a selected diaper component. For example, the side panels 90 may be formed integrally with the material layer of the backsheet 22 or may be formed integrally with the material constituting the topsheet 24. In alternative embodiments of the present invention, the side panels 90 may consist of one or more layers. a plurality of separate, spaced apart elements which are connected to either the backsheet 22 or the topsheet 24, which are attached between said layers or which comprise combinations of said arrangements.

According to specific aspects of the present invention, each of said side panels 90 may be formed as a separate element, which is then appropriately assembled and attached to the selected front and / or rear waistband portion of the diaper. In the illustrated embodiments of the present invention, each side panel 90 is coupled, through its attachment zone 94, to the backsheet of the backsheet 22, and may be operably linked to either the topsheet, the backsheet, or both. In the embodiment shown, each side panel has an internally arranged attachment zone that is folded over its respective side end edge region of the respective waist panel and laminated thereto. The side panels 90 extend transversely to form a pair of oppositely disposed band fastening strips, and are fastened to the diaper by suitable fasteners, such as adhesive, thermal or ultrasonic bonds, snap fasteners, snap fasteners or the like. Preferably, the side panels extend transversely over and beyond the end lateral edges of the backsheet and topsheet and are secured in the waistband section of the absorbent article.

The side panels 90 may consist of a substantially non-elastomeric material, such as a polymeric film, a woven fabric, a nonwoven fabric, and the like, as well as a combination thereof. According to specific aspects

427 / B of the present invention, the side panels 90 consist of a substantially elastomeric material, such as an extensible bonded laminate (SBL), a neck bonded laminate (NBL), an elastomeric sheet, an elastomeric foam or the like that is elastically extensible at least in the longitudinal direction. The corresponding longitudinally extending longitudinal direction 86. Corresponding to the meltblown and blown elastomeric fibrous webs for forming the side panels 90 are described, for example, in U.S. Pat. No. 4,663,220, issued May 5, 1987 to T. Wisneski et al., The entire disclosure of which is hereby incorporated by reference. Examples of composite fabrics consisting of at least one nonwoven fabric layer bonded to a fibrous elastic layer are detailed in EP 0 217 032 A2, J. Taylor et al., Published April 8, 1987, the entire disclosure of which is hereby incorporated by reference. of the present invention. Examples of NBL materials are described in detail in U.S. Pat. No. 5,226,992, Mormon, issued Jul. 13, 1993, the entire disclosure of which is hereby incorporated by reference.

As mentioned above, various fasteners can be used to attach the side panels 90 to selected regions of the waistband panels of the absorbent article. Specific examples of securing a pair of elastically extensible side panels to respective side portions of the absorbent article so as to extend transversely to the corresponding opposite side portions of the outer protective layer or the like component of the absorbent article can be found in U.S. Pat. No. 4,938,753, to F. VanGompel et al., Issued Jul. 3, 1990, the entire disclosure of which is hereby incorporated by reference in its entirety.

In cases where the side panels 90 consist of an elasticized or otherwise treated material so as to exhibit an elastic extensibility, such elasticized side panels may, upon request and when subjected to a test specimen of such material, be subjected to a tensile stress of 0.33 pounds per length. provide an elongation of at least 30% at the peak load in the direction of the test piece, measured perpendicular to the direction of application of the applied load (about 0,58 Newton / cm). Alternatively, it may be elastomeric

427 / B side panel 90 to provide an elongation of at least 100% and optionally an elongation of at least 300% to provide the desired improved effect.

Each of said side panels 90 extends laterally in transverse direction from mutually opposed side end portions of at least one of said diaper waistband portions 20. In an exemplary embodiment, each side panel extends laterally in transverse direction from mutually opposite end portions of a back waist portion of Each of said side panels includes a relatively outwardly extending free end section 92 having a predetermined longitudinally extending longitudinal dimension. In addition, each of said panels has a transversely extending width dimension and an attachment zone 94 which has a laminated binding means by which each of these panels is attached to the top face layer and / or the backsheet. The side panels may have a tapered or any other contour configuration in which the base length of the side panel attachment zone 94 is greater than the length of the relatively outwardly extending distal free end section 92. Alternatively, the base length of the side panel attachment zone 94 may be less than the distal length. Optionally, the side panels may have a substantially rectangular quadrilateral or substantially regular trapezoidal shape.

On each of said side panels 90, a stress transducer section 98 may be formed along its outer free end section 92 to provide a more even distribution of tensile stresses across the area of the side panel. The transfer section is designed to have a relatively high stiffness value, and in the preferred embodiments the transfer section extends over substantially the entire length of the outer free end section 92 of the side panel in the longitudinal direction. In order to firmly and reliably secure the waistband portions of the absorbent article to the body of the wearer during use, a fastening strip 44 may be attached to each of said side panels 90 such that it extends transversely outwardly relative to the side panel transfer section. .

427 / B

Each fastening strip 44 may comprise a backing layer 56 that connects to one another an inner edge of a portion of a selected fastening component, e.g., a hook material 46, associated with and corresponding to the outer free end portion of the side panel 90. The backing layer has an internally disposed first a lateral region and a second lateral region disposed transversely to the outside. Said first side region is laminated to or otherwise suitably bonded to the side panel by means of a functional structural bond by lamination. The side panel material, the backing material, and the structural bond configuration are designed and arranged such that, in combination, the functionally active transducer section 98 generates the applied stresses. Optionally, a reinforcing material additional layer may be provided on the transducer section 98 in order to increase its stiffness and further improve its capability to distribute the applied stress across the longitudinal dimension of the side panel.

The inner lateral region of the backing layer 56 may have a range in the longitudinal direction that is smaller than the length dimension of the outer free end section 92 of the side panel 90 in the longitudinal direction. Alternatively, the carrier layer 56 may have a range in the longitudinal direction that is substantially equal to or greater than the length dimension of the outer free end section of the side panel in the longitudinal direction (see, for example, FIG. 1).

The above-mentioned part of the hook material 46 is laminated to, or otherwise suitably coupled to and attached to, the outer lateral region of the backing layer by means of a functional structural bond. Specifically, in the embodiment shown, the piece of hook material 46 is laminated mainly to the inwardly facing face of the wearer facing the wearer so that the hook elements extend generally towards the interior of the absorbent article. According to the embodiment shown, the outer, laterally spaced edge of the second side region 60 of the backing layer coincides with the outer, laterally spaced apart edge of the hook material portion 46. Alternatively, the outer, transverse direction may be provided.

427 / B, the distal edge of the second lateral region 60 of the backing layer is arranged such that it is offset by a certain distance relative to the outer end, transverse, distal edge of the hook material portion 46. In either case, however, in both embodiments described, the distal edge of the hook material portion 46 provides a lateral end edge of the absorbent article.

The longitudinally extending, relatively outer edge of the side panel 90 may be spaced apart by a pitch distance from the longitudinally extending inner edge of the selected fastening component, for example, the substrate. More specifically, the outer edge of the side panel 90 may also be spaced apart, by a pitch distance, from the relatively inner edge of the hook material portion 46. This pitch distance optionally has, in a transverse direction, a range equal to or greater than the mounting range. in the transverse direction. In addition, the inwardly facing face of the wearer layer 56 is configured to exhibit limited functionally engagement with the hook elements 54. As a result, the fastening strip 44 may be configured and disposed by a longitudinally extending fold line. optionally positioned in the fastening region 50, folded into a non-functioning storage position in which the hook elements are placed on and coupled to a face facing surface of the backing layer 56. The engagement intensity between the hook material piece and the backing layer is required only to an extent sufficient to maintain the inoperative storage position. Accordingly, this intermittent intensity can be assured by applying a maximum tear force of about 1 to about 50 grams.

427 / B

In specific embodiments of the present invention, the backing layer 56 may be formed of a substantially non-elastomeric material, such as polymerization films, woven fabrics, nonwoven fabrics or the like, as well as combinations thereof. Alternatively, the backing material may consist essentially of an elastomeric material, such as an expanded bound laminate (SBL), a narrowed bound laminate (NBL), an elastomeric sheet, an elastomeric foam, or the like, as well as combinations thereof. The elastomeric material is elastically extensible at least in the width direction 88. The backing layer material may consist, for example, of a laminated fabric (SMS) comprising a core of a blow-laid layer sandwiched between two face-to-face and sponge-bonded layers. it has a total basis weight ranging from about 50 to 67 g / m ² (about 1.5 to 2 ounces per square yard (oz / yd ² )). In another embodiment, the backing material may consist solely of a spunbond nonwoven fabric having a basis weight in the range of about 50 to 67 g / m ² (about 1.5 to 2 oz / yd ² ).

Mechanical functional fasteners used to cooperate with various embodiments of the present invention may be secured by interlocking fasteners of a mechanical type, such as hooks, snap fasteners, snap fasteners, knobs, and the like, which include cooperating with each other and complementary, mechanically interlocking and interlocking components. According to specific aspects of the present invention, the fastening means may be secured by a hook and loop fastening system, anchor and loop fastening system or similar systems (collectively referred to herein as hook and loop fastening systems or fasteners). Said fastening systems generally consist of "hooks" or hook-like elements and cooperating "eyelets" or eyelet-like elements in which said hooks engage and engage with each other. Desirably, the interlocking engagement is optionally detachable or releasable. We know from the state of the art

427 / B standard fastening systems are commercially available, for example under the trade name VELCRO R.

Examples of suitable hook and loop fastening systems (" hook and loop fasteners ") are described in U.S. Pat. No. 5,019,073, issued May 28, 1991 to T. Roessler et al., The entire disclosure of which is hereby incorporated by reference in its entirety. Further examples of such hook and loop fastening systems are described in U.S. patent application Ser. No. 366,080 entitled "High Tear Strength Tape Fastener" by G. Zehner et al., Filed Dec. 28, 1994 (Verified Annotation and Brief Content No. 11,571), published as U.S. Pat. No. 5,605,735 and U.S. Pat. No. 421,640 entitled "Multi-Part Fastening System" by P. VanGompel et al., Filed April 13, 1995, the entire disclosure of which is hereby incorporated by reference into the present invention in accordance with its spirit. Examples of fastening strips provided with a carrier layer 56 are described in U.S. patent application Ser. No. 08 / 603,477, entitled " Functional Fastening System with Fastening Strips ", by A. Long et al. No. 5,624,429, the entire disclosure of which is hereby incorporated by reference into the present invention in accordance with its spirit.

In a specific embodiment of the hook and loop fastening system, the hook material portion 46 is operatively coupled and coupled to the fastening strips 44, while the loop material 80 is used to form at least one cooperating fastening suction section 78. For example, said suction section may be conveniently located on the exposed, unprotected, outwardly facing front surface of the backsheet 22. As discussed above, an alternative configuration of the hook and loop fastening system may be arranged such that the loop material 44 is attached to the fastening strip 44 while the hook material is used to form the fastening suction section 78.

427 / B

According to specific aspects of the present invention, the piece of hook material 46 may be formed from a material commonly referred to as a micro-hook material. Compliant micro-hook material usable for this purpose is distributed under the trade name CS200 and is marketed by 3M Company, a commercial agent of St. Petersburg. Paul, Minnesota. The micro-hook material may be provided with an extended " head " shaped hook and may be configured with a hook density of approximately 1,600 hooks per square inch; wherein the height of the hook is in the range of about 0.033 to 0.097 cm (about 0.013 to 0.038 inches) and the width of the hook head is in the range of about 0.025 to 0.033 cm (about 0.01 to 0.013 inches). These hooks are rigidly bonded to a thin film backing substrate having a thickness ranging from about 0.0076 to 0.01 cm (about 0.003 to 0.004 inches) and a Gurley stiffness of about 15 mg.

Another suitable and useful micro-hook material is that distributed under the trade name VELCRO CFM-29 1058 and marketed by Velcro USA, Inc., with a commercial office in Manchester, New Hampshire. This micro-hook material may be provided with hooks in the form of angled hook elements and may be configured with a hook density of approximately 264 hooks per cm ² (about 1,700 hooks per square inch); wherein the height of the hook is in the range of about 0.030 to 0.063 cm (about 0.012 to 0.025 inches) and the width of the hook is in the range of about 0.007 to 0.022 cm (about 0.003 to 0.009 inches). These hook elements are formed by coextrusion with a thin film backing substrate having a thickness ranging from about 0.0076 to 0.008 cm (about 0.003 to 0.0035 inches) and a Gurley stiffness of about 12 mg.

For the purposes of the present invention, the various values of rigidity and stiffness are determined with respect to the bending moment generated by the force whose direction of action is oriented perpendicular to the plane of the test component being subjected, defined essentially by its width and length. A suitable and suitably technological process for determining the stiffness values described in the present specification is provided by the " Gurley Stiffness Test ", which is fully described in TAPPI Test Standard T 543.

427 / B om-84 (Paper Bending Stiffness (Gurley Type Stiffness Testing Apparatus)). A suitable test apparatus for this purpose is the Gurley Digital Stiffness Tester: Model 4171-D, manufactured and marketed by Teledyne Gurley with a sales office in Troy, New York.

In various embodiments of the present invention, the stitch material may consist of a nonwoven, woven or knitted fabric. A suitable fabric to be used as a loop material may consist, for example, of a double warp knitted fabric marketed by Guilford Mills, Inc., based in Greensborough, North Carolina, under the trade designation # 34285, as well as other commonly used knitted fabrics. . Equally suitable and suitable for this purpose are the materials with regularly spaced woven nylon loops, marketed by 3M Company under the trade name SCOTCHMATE. In addition to these materials, 3M Company distributes other materials, such as separate nonwoven webs without a backing substrate and provided with an adhesive on the reverse side, or knitted eyelets.

According to specific aspects of the present invention, the placement of the stitched material need not be limited to a separate, separate suction section. Instead, the eyelet material may be secured, for example, by a substantially continuous, outwardly spaced fibrous layer that is formed integral and extends over substantially the entire exposed surface area of a fabric similar to the outwardly spaced protective layer used as part of a diaper 20. Z This implies that the eyelet material can likewise be secured through a fabric-like backsheet 22, by which an effective functional coupling of the self-locking mechanical fastening system can be achieved at substantially "any location" located on said backsheet. In practical terms, the extent of the applicability and arrangement of the loop material will depend only on the cost of the loop material.

427 / B

The fastening elements may, in various embodiments of the present invention, be functionally coupled to the underlying substrate using any one or more attachment means, also used to form and interconnect various other components of the absorbent article. It is desirable to be able to form the fasteners of the various base and complementary fastening regions in an integral whole, for example by molding, coextrusion or similar technological processes, together with the underlying substrate. Thus, the substrate substrate and the fasteners may be formed from substantially the same polymeric material, which eliminates the need for a separate manufacturing operation of fastening the fasteners to a previously formed substrate substrate. In the illustrated embodiments of the primary fastening region, the hook elements may be formed integrally with the substrate, for example, by coextrusion of the substrate and the hook elements of substantially the same polymeric material.

From the above, it must be understood that the strength of said interlocking or other interlocking connection between the substrate and the respective fastening component must be greater than the maximum force required to tear the fastening strips 44 from its releasable interlocking engagement with the respective suction section. absorbent article.

Calculation methods and test procedures

Procedure for determining the thickness in a partially saturated state

The thickness (h) of each layer in the partially saturated state can be determined based on the previously determined input variables and parameters and using the following procedure.

427 / B

Goal:

Determining the thickness (h) of each layer portion in a partially saturated state.

Equipment and materials used:

Glass Petri dish (100 x 15 mm No. 3160 - 101 - Fisher's Catalog No. 08-747C).

Blood saline, e.g. Catalog 8504, available from Stevens Scientific, a division of Comwell Corporation, with offices in Riverdale, New Jersey; or equivalent.

0.05 inch (0.345 kPa) thickness measuring apparatus with a 3 inch (7.62 cm) diameter base.

Nibbler - 3 inch (7.62 cm) circumferential diameter.

Laboratory scales.

Laboratory stopwatches.

Testing procedure

Cut a test sample to be tested, 3 inch (7.62 cm) in diameter, at a die cutter.

Calculation of saturation (v: g / g - mass of liquid in grams per mass of test sample in grams) of the layer, based on saturation of 0,6 g / cm ^{2 of the} mixture of absorbent and superabsorbent material; and applying the technological procedure described in the paragraph "Flow conductivity calculation".

Weigh the test sample in the dry state and record its measured mass.

Calculation of the amount of liquid saline to be added to the test sample for testing purposes by multiplying the dry weight of the test sample by the value of the desired saturation level.

Dispense the calculated amount of liquid saline into a Petri dish and disperse it over the surface plane to distribute the solution evenly to the test sample.

427 / B

Place the test sample in a petri dish so that the sample remains flat.

Remove the test sample from the Petri dish after a period of 30 minutes.

Measure the thickness of the test sample (in: mm) under a controlled limited pressure of 0.05 psi (0.34 kPa) and record its measured size.

The values of the thickness value (h) in the partially saturated state can be applied in the equations used to calculate the flow conductivity of the composite absorbent system.

Flow conductivity calculation

The flow conductivity of the absorbent core when the absorbent material is loaded with a liquid of 0.6 g / cm ² to express the absorbency and absorbency of the absorbent core structure when the absorbent core is in a partially saturated state. The flow conductivity can be characterized by the following equation:

Flow conductivity value = K-ιhi + K ₂ h ₂ + K ₃ h ₃ ...

where

K is the permeability of each layer at a fixed saturation, and h is the thickness of each layer at a fixed saturation.

The permeability (K) of each layer contained in the absorbent core can be calculated as follows:

Each layer present in the absorbent core represents a combination of substantially non-swellable fibrous materials and superabsorbent material in the form of particles, fibers or flakes.

The mathematical expression of the permeability (K) for the structural set of cylindrical, irregularly oriented elements and for the structural set of spherical particles is as follows:

427 / B

For cylindrical and other, regular or irregular, longitudinal fibrous form configurations:

0,30 ε

K = (_) (1 -e) (_) ²⁵ (SA / V) ² 1 - ε

For generally spherical and other, regular or irregular, particle shape configurations:

0,3555 ε

K = (_) (1 - ε) (_) ²³⁵ (SA / V) ² 1 - ε where

SA / V is the ratio of the surface area to the volume of solid particles in cm ^-1 and ε is the void content, expressed as the ratio of the pore volume (gaps) to the total volume of the substrate as a whole.

The basis for the above-mentioned mathematical expression of transmittance (K) is the publication "Low Reynolds Number Hydody Namies" (Hydrodynamics of Materials with Low Reynolds Number) by Happel and Brenner, publ. Noorhoff International Publishing (1973). The mathematical expression of the permeability for cylindrical and spherical particles was derived based on the facts presented in this publication by applying them to the simpler, shape configurations described above to obtain the values of the respective multipliers and multipliers.

It has been found that all of the liquid supplied to the absorbent structure during the first impact is substantially absorbed by the superabsorbent material before the second or further subsequent impact of the liquid and the next occurs. In view of this assurance, for the purpose of calculating the permeability value necessary to calculate the flow conductivity value, all of the liquid specified above

427 (B g / cm ² ) is thus considered to be absorbed by the superabsorbent material. Therefore, when calculating the ratio of the void space (s) to the volume and the surface area to the volume for the superabsorbent material, the volume of this liquid is included as part of the solid particle volume. In this state, the voidiness (t (s) of the basic material is determined based on the relation:

ε = 1 - [(particulate volume + liquid volume) / (total volume occupied by the test sample wet)] where:

the total wet volume occupied by the test sample is the value which represents the product of the area and the measured thickness of the test sample. Said thickness of the test sample may be determined, for example, based on the above-described Thickness Detection Procedure in a partially saturated state.

The surface area to volume ratio (SA / V) used in the respective relationships and equations to calculate the permeability of the various components is calculated based on the surface area per volume recalculation for either fibers or particles, according to the respective morphology of the individual components. For fibers, the surface area to volume ratio is equal to the circumference to area cross-sectional area perpendicular to the longitudinal axis of the cylindrical member.

For a cylindrical element with a circular cross-section, this ratio is determined, for example, as follows:

SA / V = p / a = 2 / r, where:

r is the cross-sectional radius of the cylindrical element in cm.

For strip shape configurations and the like, i. those configurations in which the cross-section has the shape of a general quadrilateral, this ratio shall be determined using the formula:

SA / V = p / a = 2. (width + thickness) / (width. thickness)

427 / B

In the case of fibers having more complex cross-sectional configurations, the circumferential to cross-sectional area ratio can be determined using sufficiently known microscopic techniques. See, for example, "Quantitative Stereology" by E. E. Underwood, publ. Addison Wesley Publishing Co. (1970).

Based on the above relationships, the surface area to volume ratio of substantially non-swellable fibrous materials can be determined by the "SA / V" value (or the fiber surface area to fiber volume ratio) corresponding to the respective cross-sectional shape configuration of the fibers. For example, cellulose-based fibrous tufts generally have a shape similar to a longitudinal strip with a rectangular cross-section. Then, for cellulose-based fibrous tufts with a thickness of 8 µm (0.0008 cm) and a width of 40 µm (0.0040 cm), the surface area to volume ratio will be:

SAA = p / a = 2. (8 + 40). 10 ^-4 / ((.40) .10 ' ⁸ )

SAA / = 3000 cm ^-1 .

The superabsorbent material may, in terms of its morphology, be in the form of particles, fibers, flake elements or combinations thereof. Moreover, these materials may be isotropic or anisotropic in terms of their swelling capacity. The vast majority of commercially available superabsorbent materials are in the form of particles whose swelling is isotropic. Such superabsorbent particles can be considered as spherical particles for purposes of the present calculations. For the preliminary calculation of the surface area to volume ratio of the superabsorbent material, assuming that the sizes of all such particles are substantially identical, the calculation of the surface area to volume ratio for the spherical elements (beads) can be used. The ratio of the surface area to the volume of the spherical element is determined by:

SAA / = 3 / r, where r is the radius of the spherical element in cm.

427 / B

However, superabsorbent materials may also consist of particles with a particle size distribution. Where this distribution is essentially monomodal, the surface area to volume ratio may be calculated by weight. For a given particle size distribution, the ratio can be calculated using the following formula:

. Σ, (r, n. ² )

With A / V = _

Σ, (r ^3. N ₀ where n is the mean radius of the particle in the i-th fraction n, is the number of particles in the i-th fraction, where n, = m, / (psap (4/3). Π. R ³ ) where m, is the mass fraction of particles in the i-th fraction, in grams,

Psap is the dry particle density of the superabsorbent material, in g / cm ³ .

In the case of a multimodal distribution, for example a bimodal distribution, the permeability must be calculated separately for each modal group of particles based on the use of the specific permeability calculation of the composite materials described in detail below. In view of the above, in this case, the calculation of the surface area to volume ratio by means of mass conversion must be performed separately for each modal group of particles. Typically, for at least 6 to 8 fractions with different particle sizes, a preliminary calculation of the particle size distribution of the superabsorbent material must be used.

427 / B

In addition, the contribution and benefits of incorporating superabsorbent material to determine the permeability of the composite absorbent system complicate its swelling due to liquid uptake. Specifically, the size, and therefore the surface area to volume ratio, of the particles of superabsorbent material will depend on the saturation level of the material.

The relation for calculating the surface area to volume ratio of isotropic swelling particles of superabsorbent material as a function of the liquid content is:

(SA / V) _dry (SA / V) _We, = _ [1 + (S. PASR / Pi)] ^{<1 "3>} where (SA / V) wet, the ratio of surface area to volume of the superabsorbent material wet-on cm ' ¹ ,

S is the saturation of the superabsorbent material expressed as the amount of grams of liquid to the weight of the superabsorbent material, in grams,

Psap is the dry particle density of the superabsorbent material, in g / cm ³ , pi is the liquid density, in g / cm ³ , (SA / V) _dry is the ratio of surface area to dry particle particle volume in cm ^-1 .

Superabsorbent materials may also be present in fibrous form. Accordingly, it has been found that fibrous superabsorbent materials generally swell anisotropically. This obviously means that the volume increase of the fibers with the increase in the liquid content takes place first in the radial direction, while the length of the fibers remains substantially constant, that is to say unchangeable. In this case, the ratio of surface area to volume of the swollen fibers of the superabsorbent material is as follows:

427 / B (SA / V) lengths (SAAOwet = _ [1 + (S. psap / Pi)] ^(1/2)

Based on the above relationships for calculating the surface area to volume ratio as a function of the liquid content of the superabsorbent material, it is possible to calculate the specific surface area to volume ratio of the superabsorbent material at the specific liquid content. The saturation level of each superabsorbent material in each absorbent layer must be determined prior to performing the actual surface area to volume ratio of each superabsorbent material to be used for the permeability calculation based on the above mathematical relationships. The following theoretical considerations describe the procedure used to pre-calculate the saturation level of each superabsorbent material present in the absorbent core.

It has been found that, over a period of time between the supply of liquid during its first and second impact, substantially all of this liquid is absorbed by the superabsorbent material contained in the system. In addition, it has further been found that the liquid fed to the absorbent structure during its first impact is distributed between the superabsorbent materials present in accordance with their relative proportions and the relative rate of liquid uptake. For the liquid load specified above (0.6 g / cm ² ), the saturation, Sj, expressed as the ratio of the amount of liquid in grams to the weight of superabsorbent in grams, each of the absorbent core contained in the superabsorbent material, can be calculated as follows:

(/ pj 0,6)

S, = _ (bwj. 10 ' ³ )

427 / B where:

bwj is the basis weight of j-th superabsorbent material, in g / m ² , f _n is the liquid partition coefficient of j-th superabsorbent material.

The liquid partition coefficients, f _P j, are calculated for each superabsorbent material contained on the basis of their relative amount and relative liquid uptake rate using the relation:

/ _Rj . bwj

Ä = _

(, (/ Rj bwj) where:

bwj is the basis weight of j-th superabsorbent material, in g / m ² ,

7ri is a coefficient of relative liquid uptake rate of another superabsorbent material.

The coefficient of relative liquid uptake rate, f _R , for each superabsorbent material contained, is given by:

Λ = τι / η where:

That is, the uptake time (timing) required to overload 60% of the value of the balanced absorbent capacity of the j-th superabsorbent material, determined based on the Zero Load Inundation Capacity Test (FAUZL) described in detail below.

427 / B

For purposes of illustrating the calculation method, a two-layer absorbent structure having the following composition is considered as an example:

Layer 1:

Type 1 superabsorbent material with a recalculated particle size of 400 µm and a basis weight of 120 g / m ² , τι is 5 minutes.

Technical cellulose in the form of a fibrous tuft with a basis weight of 120 g / m ² and a cross-section of fibers of 8 µm x 40 µm.

The thickness measured at the saturation level specified below is 0.55 cm.

Layer 2:

Superabsorbent type 2 material with a recalculated particle size of 400 µm and a basis weight of 150 g / m ² , τι is 10 minutes.

Technical cellulose in the form of a fibrous tuft with a basis weight of 130 g / m ² and a fiber cross-section of 8 µm x 40 µm.

The thickness measured at the saturation level specified below is 0.51 cm.

For superabsorbent materials used in the above layers:

/ R. = 5/5 = 1 / r2 = 5/10 = 0.5 a

1.120 / pl = _ = 0.62 (1.120 + 0.5.150)

427 / B

1.150 / _Ρ 2 = _ = 0.38 (1.120 + 0.5.150) where:

(0,62.0,6)

Si = _ = 31 g / g (120.10 · ⁴ ) (0.38.0.6)

S ₂ = _ = 15.2 g / g (150.1 θ ' ⁴ )

The above calculations correspond only in cases where the total liquid capacity of FAUZL superabsorbent materials is not exceeded at a specific liquid load of 0.6 g / cm ² . If the capacity of a particular particular superabsorbent material is exceeded under these conditions, its saturation is adjusted to a balanced value, assuming that excess liquid is stored in the other superabsorbent materials contained therein in a manner consistent with the facts set forth herein.

On the basis of the amount of liquid located in the superabsorbent material, it is possible, using the corresponding equations mentioned above, to calculate the surface area to volume ratio of the particles and / or fibers of the superabsorbent

427 / B of the material in the swollen state, calculate the respective surface area to volume swollen particles or fibers for each absorbent layer. For particulate superabsorbent materials, equations intended to calculate the permeability of spherical particles must be used, and for fibrous superabsorbent materials, the equations intended to calculate the permeability of cylindrical, longitudinal particles must be used.

In this particular example, the superabsorbent materials take the form of particles, so that the respective surface area to volume ratios when the absorbent core contains 0.6 g / cm ² liquid, using the corresponding equations, are as follows:

Superabsorbent Material Contained in Layer 1:

(SA / V) sap i - _ = [1 + (S. PSAP / Pi)] ^(1/3)

3 / (200. 10 ' ⁴ ) = _ = 41.6 cm ^-1 [1 + (31. 1.48 / 1)] ^(1.3)

Superabsorbent material contained in layer part 2: (SA / VJdry (SA / V) sap 2 ⁼ _ ⁼ [1 + (S / p SAP / Pi)] ^(1/3)

3 / (200.10 ' ⁴ ) _ = 52.4 cm ^-1 [1 + (15.2, 1.48 / 1)] ^(1.3)

427 / B

Technical cellulose in the form of a fibrous tuft, contained in both of the aforementioned layers:

SA / V = p / a = 2. (8 + 40) .10 ' ⁴ / ((8.40). 10' ⁸ )

SA / V = 3000 cm ^-1

In this state, it is then possible to determine and adapt the permeability equations to calculate the permeability of the particular components contained in the individual layer portions used to form the absorbent core of the composite absorbent system based on the above mathematical permeability formulas for the structural fiber assemblies or structural particle assemblies. However, the aforementioned mathematical permeability expressions for the structural sets of fibers and / or particles only apply if the total porous substrate contains either only fibers or only particles of superabsorbent material dispersed in its volume. In the case where both the particles and the fibers are contained in the volume of the respective substrate with a specific void content, the combined equations are used for the calculation. The procedure used to combine the relevant mathematical equations is based on the principle of "self-consensus method" designed, with theoretical explanation, and described in the section "Performing Predictions by Self-Consistent Method and Finite Element Simulation". and limited particle simulation) by AL Berdichevski and Z. Cai, publ. in "Polymer Composites", no. 14, 2.1993.

For the purposes of the present disclosure, the basic assumption set in the background of said self-agreement method is that the permeability is substantially homogeneous throughout the porous substrate. Accordingly, the local void values corresponding to the presence of fibers or particles are determined such that their respective local permeability is equal. The above computation is subject to the restriction that the total porosity (s _CO mp) the structure be maintained at a specific value which is determined on the basis of the measured surface area and thickness of the sample, as described above.

427 / B

The simplest composite layer composition comprises two components. In this case, two equations will be required to calculate the permeability of the composite layer based on the self-agreement method. For the above-mentioned exemplary embodiment comprising two composite layers, respectively. The following equations will be used to calculate the permeability of the composite absorbent structure based on the self-agreement method.

The equations for calculating the permeability of the layer portion 1 and the layer portion 2 are as follows:

Layer 1:

for fibrous material:

0,30 Efiberl

Kfiberl ⁼ (_) (1 ^- Efiberl) (_) 2.5 (3,000) 1 - Sfiberl

For superabsorbent material:

0,3555 esapi

Ksapi ⁼ (_) (1 - esapi) (_) 2.35 (41.6) ² 1-esapi

Layer 2:

for fibrous material:

0.30 Efiber2

Kfiber2 ⁼ (_) (1 ~ Efiberô) (_) 2.5 (3,000) 1 - Sfiber2

427 / B

For superabsorbent material:

£ 0.3555 sap2

Ksap2 = (_) (1 - esap2) (_) 2.35 (52.4) ² 1 - ssap2 where:

The fibers, esapi, Efi _b er2 and ssap2 correspond to the local voidiness values of the respective fibrous and superabsorbent materials contained in the layer portions 1 and 2. The sum of the local voidiness must give a corrected total void density ( _{C C} omp) obtained by thickness measurement, described in detail and the following relationship:

bWtcomp 10 ^-4 _[Σ Κ (fk / pk) + Ej (fj / Pj) + Σ; (Sj. Fj / pj)] where:

bwtcomp is the basis weight of the composite, v (g / m ² ) fk is the mass fraction of the k-th fibrous material contained in the composite, ή is the mass fraction of the j-th superabsorbent material contained in the composite, where:

Ek fk * Ej fj ⁼ 1 a

pk is the density of the k-th fibrous material, in g / cm ³ ,

Pi is the density of the j-th superabsorbent material, in g / cm ³ ,

427 / B ρ-ι is the density of the liquid, in g / cm ³ ,

Sj is the saturation level of the superabsorbent material, expressed as the amount of liquid in grams to the weight of the superabsorbent material in grams, hcomp is the thickness (h) of the composite at the liquid loading level equal to the total liquid loading of the composite.

bwtcomp .¾ .10- ⁴ (S i. ή).

For the above embodiments, comprising two composite layers, each consisting of only one type of fibrous material and one type of superabsorbent material, then the total density of the fibrous materials in both layers will be 1.5 g / cm ³ and the total density of the superabsorbent materials in both. layers 1.48 g / cm ³ ; other quantities such as the weight of the fractions of superabsorbent material, the liquid loading and the individual heights of each layer of the composite structure are determined using the above relationships.

Total gap values are calculated as follows: Layer 1:

240. W ⁴ [(0,5 / 1,5) + (0,5 / 1,48) + (31,5,5)] ε = 1 -_ = 0,29 hcomp

Layer 2:

450.10 ^-4 [(0.67 / 1.5) + (0.33 / 1.48) + (15.2.0.33)] ε = 1 -_ = 0.50 hcomp

The permeability values of the two layers, calculated on the basis of the above-mentioned self-agreement method, are as follows:

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Layer 1:

K = 1.6.10 ^-6 cm ²

Layer 2:

K = 1.1. 10 ' ⁶ cm ² ,

A simple exemplary embodiment of a dual-layer absorbent structure serves for illustrative purposes of calculating the permeability of the composite structure. However, the composites used to form the absorbent core of the present invention may comprise more than two different components. Thus, in such cases, and given the appropriate permeability calculation of the composite structure based on the use of the above-described self-agreement method, it is necessary to derive a corresponding mathematical expression of the permeability for each component contained in each given composite layer portion of the absorbent structure. For example, if the composite layer portion comprises two types of fibrous materials and two superabsorbent materials, using a self-agreeing method for mathematically expressing the permeability of the composite absorbent structure, four equations will be necessary to calculate the permeability of each of the contained materials.

Based on the determined and for each layered portion of the absorbent core, as described above, in the partially saturated state of the calculated permeability values of the composite absorbent structure and thickness (thickness size h), it is now possible to calculate the desired flow conductivity value of the absorbent system. In this state, see above, it is therefore:

Flow conductivity value = ΚιΙη + K ₂ h ₂ + K ₃ h ₃ + ...

Thus, for an exemplary embodiment comprising two layers is:

Flow conductivity value = (1.6.10 ^-6 . 0.55) + (1.1.10 ^-6 . 0.51) = = 1.4.10 ^-6 cm ³ .

427 / B

Although the above permeability and flow conductivity calculations are exemplified only for a two-layer absorbent structure in which each of its layers contains one isotropic swellable superabsorbent material and one type of fibrous material, the above detailed flow conductivity calculation may be extended to cases. comprising more than two layers, as well as the permeability calculation (K), in accordance with the description presented herein, can easily be adapted to the permeability calculation of more complex materials composed of multiple components.

Value of potential liquid wicking

Set objective

This test is used to determine the ability of the absorbent material to withdraw liquid from the acquisition zone.

Brief summary

Determination of the quantity of liquid to be applied to a test sample based on the above calculations using the liquid partition coefficient. Allowing the test sample to absorb the liquid contained in the reservoir and determining the amount of liquid that has been withdrawn from the receiving zone.

Equipment and materials used

Plate of plexiglass or similar material, measuring 21 cm x 21 cm and having a thickness of 5 mm or less.

Suitable liquid reservoir.

Laboratory scales.

Holder to hold a test sample of absorbent material in the vertical position while adding liquid to the sample.

427 / B

Quick-release clamps for attaching the test specimen to a Plexiglas plate, such as "Medium Binder Clip" clamp no. catalog 10050, available from IDL Corporation, Caristadt, New Jersey.

Laboratory oven with heating to 150 °.

Tested materials

Test liquid saline; recommended is blood saline, marketed under catalog number 8504 Blood bank saline by Stephens Scientific, a division of Cornwell Corporation with a business office in Riverdale, New Jersey; or equivalent.

Preparation of the test sample

Taking the test portion of the layer portion from the absorbent article to be tested or removing the corresponding test portion of the layer portion without breaking so that it exhibits the same shape configuration that the layer portion has in the absorbent article. Each absorbent layer must be separated from the other components and tested separately before testing.

Mark the receiving destination using an indelible ink marker. The receiving target position of the test layer is determined by the intended arrangement of the layer in the finally completed absorbent core. This receiving target position is located in the transverse direction of the centered region, which is located inwardly to the front limit end edge of the most forwardly extending absorbent layer of the absorbent core by a distance equal to 36% of the total length of the absorbent core. Accordingly, it is not necessary to subject this furthest-extending absorbent layer of the absorbent core to the test.

Marking of the receiving zone on the test sample using an indelible ink marker. The test zone receiving zone of the test layer is determined by the intended arrangement of the layer in the finally completed absorbent core. This receiving zone of the test layer of the test layer is that zone of the test sample that lies between two transverse

427 / B lines. The first of these lines is disposed inwardly from the leading edge end edge of the furthest extending absorbent layer of the absorbent core by a distance equal to 24% of the total length of the absorbent core. The second line is positioned inwardly from the leading edge end edge of the furthest-extending absorbent layer of the absorbent core by a distance equal to 59% of the total length of the absorbent core. Both of these lines are substantially perpendicular to the longitudinally extending axis of symmetry of the absorbent core. In the case where the two lines of the receiving zone do not fall within and are outside the limit end edges of the test sample of the absorbent material to be tested, then the liquid wicking value of the test sample will of course be zero.

Determination of the amount of liquid to be absorbed by the test sample using calculations using the liquid partition coefficient based on the above detailed description of the calculations for determining the flow conductivity value. However, rather than calculating the saturation of the superabsorbent material for each individual layer, the predicted amount of liquid contained in each absorbent layer is determined. This calculation can be made using the following relation:

The amount of liquid contained in the absorbent layer &quot; ⁼ &quot; ⁼ 1 / µl of the receiving zone surface area (e.g., for an exemplary embodiment, determined in connection with the flow conductivity determination description and for a 100 cm ² receiving zone surface area ⁾ the following values are obtained: an amount of 61.6 g of liquid in the layer portion 1 and an amount of 38.4 g of liquid in the layer portion 2).

Procedure for preparation of test conditions

Placing a test specimen mounted on a Plexiglas plate using quick-release clips so that the indicated target position is located directly on the bottom of the test apparatus.

427 / B

Fill the reservoir with liquid so that the liquid level is approximately 1 cm from the top edge.

Place the liquid reservoir on the laboratory weighing pan.

Testing procedure

Balance of laboratory scales.

Suspend the test sample in the reservoir so that the absorbent material under test contacts the liquid level.

Use of laboratory scales for the purpose of comparing the actually absorbed amount of liquid absorbed with the amount determined on the basis of the calculations described above. Removal of the test sample from the reservoir at the time when the amount of liquid weighed coincides with the amount of liquid determined using calculations by means of a liquid partition coefficient of ± 5 g / m ² .

Leave the test sample upright for 5 minutes.

Trimming the test sample at the positions indicating the receiving zone and removing the formed central portion. Weighing of the remaining sections of the test sample.

Dry the remaining sections of the test sample in a laboratory furnace in which these samples are left overnight.

Weighing the dry samples and determining the difference in wet and dry weights by subtracting the dry weight of the test sample from the wet weight of the test sample, the difference being the amount of liquid that has been removed from the receiving zone. The amount of liquid removed from the acquisition zone (i.e. the amount measured in the previous step) is divided by the total amount of liquid that has been applied to the absorbent layer in the liquid wicking test; whereupon the calculated fraction is multiplied by 100. The result is the value of the potential wicking of the liquid-tested layer portion.

427 / B

Combined Conductivity / Absorbency (C)

The combined conductivity / absorbency value can be determined using the following equation:

(LWV)

C = (FCV) + _ (3.10 ⁶ ) where

FCV is the flow conductivity value in cm ³ , LWV is the liquid wicking value and (3.10 ⁶ ) has a cm- ³ dimension.

Modified absorption absorbency under load

Set objective

This test is designed to measure the capability of particulate superabsorbent polymerization material (SAP) to absorb saline under a constant load of 0.3 psi (2.07 kPa). More precisely, the test serves to measure the amount of saline absorbed by 0.160 g of superabsorbent polymeric material with a particle size falling through a # 30 mesh (US standard) screen and retained on a # 50 mesh (US standard) screen, which it is distributed over an area of 5.07 cm ² and is subjected to a pressure of 0.3 psi (2.07 kPa). A suitable and useful test apparatus is shown in FIG. 10 to 14.

427 / B

Equipment and materials used

Electronic scales with an accuracy of 0.001 grams (minimum load capacity 200 g).

Cylinder assembly: plastic cylinder 120 having an inner diameter of 1 inch (25.4 mm), provided with a 100 mesh stainless steel screen attached to the bottom of the cylinder; plastic disk piston 122 weighing 4.4 grams and 0.995 inch (25.27 mm) in diameter. The diameter of the disc piston is 0.005 inch (0.13 mm) smaller than the inner diameter of the cylinder.

A weight of 100 grams 124 having a diameter of 0.984 inches (25 mm).

0.9% sodium chloride (NaCl) solution in blood saline.

Saline tank 126.

Electronic timer 140 capable of reading and counting for 200 minutes at 1 second intervals.

Weighing paper.

Sieve test kit, standardized to U.S. standard. Standard Testing Sieve (A.S.T.M. E-11 Specification), comprising one receiving tray, one # 30 mesh screen, one # 50 mesh screen and one lid.

A tapping mechanism arranged above the test sample and intended to ensure adequate and consistent tapping of the plate piston, as can be seen from FIG. 10 and 12. This tapping expels each trapped air surrounding the superabsorbent polymerization material (SAP) and ensures that the liquid present soaks the surface of the SAP accordingly. In this arrangement, the motor 128 drives the shaft that provides the stroke of the connecting rod 130 between its upper and lower dead centers. At the lower end of the connecting rod 130 there is provided a rubber foot 132 which has a diameter of 13 mm and which is shown in FIG. 12. The connecting rod stroke is 3 cm and performs a complete stroke cycle between upper and lower dead center every 0.7 seconds. The maximum pressure that the disk piston will apply to SAP is 0.16 psi (0.11 kPa).

The clamping fixture 134 shown in FIG. 10, provided with a vacuum channel 136 which allows the interstitially absorbed liquid to be sucked from

427 / B of the test sample. The vacuum channel is adapted to the base of the cylinder assembly. When the cylinder assembly containing the test sample is placed in the fixture 134, the free, non-entrapped liquid between the particles of superabsorbent material of the test sample is aspirated. A suitable pump for this purpose is a suction pump 138, which is applied to a test sample with a vacuum of 100 torr (13.3 kPa) or less.

In FIG. 10 shows a completely arranged test apparatus. It should be noted here that the electronic timing device 140 is preferably used to control and control the duration of action of the tapping and vacuum mechanisms. In this particular arrangement, the tapping mechanism is mounted on the slide 142 that allows the mechanism to be moved between a plurality of test apparatuses stored in the test apparatus.

Testing procedure

1. Preparation of a superabsorbent polymerization material by sieving it on a standardized screen test assembly to provide a minimum amount of 0.160 g of such a particle size material that falls through a # 30 mesh screen and is held on a # 50 mesh screen.

2. Weigh an amount of 0.160 g (to an accuracy of ± 0.001 g) by sieving the obtained superabsorbent material in step 1 using weighing paper.

3. Slowly pour the weighed amount of superabsorbent material into a 100 mesh sieve cylinder. During pouring, any contact of the superabsorbent material with the cylinder walls must be avoided due to possible adherence of material particles to these walls. After pouring the absorbent material, a slight shaking of the roll is performed until the material particles are evenly distributed on the screen.

4. Placing the plastic piston in the cylinder. Weigh the assembled cylinder assembly and record the measured weight as the "weight of the superabsorbent material including the cylinder assembly".

427 / B

5. Fill the physiological saline reservoir with blood saline to a height of 1 cm.

6. Place the cylinder assembly in the saline reservoir so that it is located directly below the connecting rod of the tapping mechanism and the electronic timing device is started. Activating the tapping mechanism and performing the tapping for a period of 8 seconds.

7. Placing a 100g weight on top of the disc piston of the cylinder assembly at a time interval of 5 seconds after the 8 second tapping period has ended, as shown in FIG. 11th

8. Removal of the cylinder assembly after 200 minutes of storage from the reservoir, weighing of the assembly and its subsequent placement, including a 100 g weight, in the vacuum fixture, see fig. 13. Apply vacuum to the cylinder assembly for a period of 6 seconds.

9. Remove the 100 g weight from the cylinder assembly, weigh the cylinder assembly without the weight and record the measured weight.

Test results and analysis

Calculation of the amount of absorbed saline in grams per gram of superabsorbent polymerization material for each test sample tested. The result is a modified MAUL value of the superabsorbent material.

Zero Load Inundation Capacity (FAUZL)

Set objective

This test is designed to measure the uptake rate of physiological saline solution by superabsorbent polymerization material (SAP) in particulate form. The test is to measure the amount of saline as a function of time absorbed by 0.160 g of superabsorbent polymerization material (which is either dry or pre-saturated at the start of measurement) distributed over an area of 5.07 cm ² and subjected to a pressure of 0.01 psi (0.069 kPa). Based on the found

The time characteristic (Tau) for reaching 60% of the balanced absorption capacity is determined by 427 / B of the resulting absorbency over time.

Equipment and materials used

Electronic scales with an accuracy of 0.001 g (minimum load capacity 200 g).

Cylinder assembly: plastic cylinder 120 having an inner diameter of 1 inch (25.4 mm), provided with a 100 mesh stainless steel screen attached to the bottom of the cylinder; plastic disk piston 122 weighing 4.4 grams and 0.995 inch (25.27 mm) in diameter. The diameter of the disc piston is 0.005 inch (0.13 mm) smaller than the inner diameter of the cylinder.

0.9% sodium chloride (NaCl) solution in blood saline.

Saline reservoir.

Electronic timing device 140 capable of reading and counting for 200 minutes at 1 second intervals.

Weighing paper.

A tapping mechanism arranged above the test sample and intended to ensure adequate and consistent tapping of the plate piston, as can be seen from FIG. 10 and 12. This tapping expels each trapped air surrounding the superabsorbent polymerization material (SAP) and ensures that the liquid present soaks the surface of the SAP accordingly. In this arrangement, the motor 128 drives the shaft that provides the stroke of the connecting rod 130 between its upper and lower dead centers. At the lower end of the connecting rod 130 there is provided a rubber foot 132 which has a diameter of 13 mm and which is shown in FIG. 12. The connecting rod stroke is 3 cm and performs a complete stroke cycle between upper and lower dead center every 0.7 seconds. The maximum pressure that the disk piston will apply to SAP is 0.16 psi (0.11 kPa).

The clamping fixture 134 shown in FIG. 10, provided with a vacuum channel 136 that allows the suction of interstitially absorbed liquid from the test sample to be performed. The vacuum channel is adapted to the base of the cylinder assembly. After placing the cylinder assembly containing the test specimen in the fixture 134, the free, non-entrapped liquid between the

427 / B particles of test sample superabsorbent material. A suitable pump for this purpose is a suction pump 138, which is subjected to a vacuum of 100 or less (13.3 kPa) on the test sample.

In FIG. 10 shows a completely arranged test apparatus. It should be noted here that the electronic timing device 140 is preferably used to control and control the duration of action of the tapping and vacuum mechanisms. In this particular arrangement, the tapping mechanism is mounted on the slide 142 that allows the mechanism to be moved between a plurality of test apparatuses stored in the test apparatus.

Testing procedure

1. Weigh an amount of 0.160 g (to ± 0.001 g) by sieving in step 1 the obtained superabsorbent material using weighing paper.

2. Slowly pour a weighed amount of superabsorbent material into a 100 mesh sieve cylinder. During pouring, any contact of the superabsorbent material with the cylinder walls must be avoided due to possible adherence of material particles to these walls. After pouring the absorbent material, a slight shaking of the roll is performed until the material particles are evenly distributed on the screen.

3. Placing the plastic piston in the cylinder. Weigh the assembled cylinder assembly and record the measured weight as the "weight of the superabsorbent material including the cylinder assembly".

4. Fill the physiological saline reservoir with blood saline to a height of 1 cm.

5. Place the cylinder assembly in the saline reservoir so that it is directly below the connecting rod of the tapping mechanism and the electronic timing device is started. Activating the tapping mechanism and performing the tapping for a period of 8 seconds.

427 / B

6. Removal of the cylinder assembly after a period of 5 minutes has elapsed from its storage from the reservoir, stopping the timing device, and placing the cylinder assembly in the vacuum clamp, see FIG. 14. Apply vacuum to the cylinder assembly for a period of 6 seconds.

7. Weigh the cylinder assembly and record the measured weight.

8. Put the cylinder assembly back into the saline reservoir and place it under the tapping mechanism and restart the timing device. It should be noted here that the time interval between removing the cylinder assembly from the saline container in step 6 and reinserting it in the saline solution in step 8 must not exceed 30 seconds. Repetition of the first, initial test series, i. soaking the test sample, removing it from saline, subjecting it to vacuum, and weighing it in order to collect and record the data at increasing wetting times of 1, 5, 10, 15, 30, 45, 60, 75, 90 and 120 minutes.

9. The test procedure described in steps 1 to 8 is performed three times in total.

Test results and analysis

Calculation of the amount of absorbed saline in grams per g of superabsorbent polymerization material and evaluation of the measured amount as a function of increasing wetting time.

Determination of the Resulting Balanced Absorption Capacity of Superabsorbent Polymerization Material (SAP): If this capacity varies less than 5% of the average SAP capacity obtained after 90 and 120 minutes (the average calculated from the measured values of all three tests), then as a balanced equilibrium absorption capacity or inundation capacity at zero load (FAUZL) shall use the capacity measured after 120 min. If this capacity varies by more than 5% of the average capacity, then it is necessary to repeat and include testing of the test sample and to supplement this testing by measuring the amount of absorbed saline at a soak time of 200 min. As a balanced absorption capacity, or FAUZL, in this case the capacity measured after 200 min.

427 / B

Determination of the time characteristic (Tau) for achieving 60% of the equilibrium absorption capacity by interpolation: This is done by calculating the capacity at 60% of its equilibrium value, while estimating the corresponding time interval necessary to achieve this capacity using a diagram. The interpolated time characteristic to reach 60% of the capacity (using the described procedure) is obtained by performing linear interpolation using the measurement data located on both sides of the predetermined time interval.

Calculation of the arithmetic mean of the interpolated time characteristic to achieve 60% of the balanced capacity (average of three test runs). This average time characteristic value is referred to as the "Tau (τ)" value.

Wetting angle of the fibrous material

A suitable and suitable method for measuring the wetting angle of a fibrous material is described in detail in U.S. Pat. No. 5,364,382, the entire disclosure of which is hereby incorporated by reference in its entirety. The measurement of the wetting angle of the fibrous material by the liquid is particularly useful for determining and evaluating the wettability of the fibrous materials. A repeated cycle of measuring the wetting angle of the individual fibers of the fibrous material under the distillation time may be performed using a Cahn SFA-222 Analyzer and WET-TEK software for evaluating the measured data. The Cahn SFA-222 Analyzer is marketed by Cahn Instruments, Inc., located in Cerritos, California, and the WET-TEK software by Biomaterials International, Inc., located in Salt Lake City, Utah. The fibrous materials are subjected to testing in three measurement cycles and the distilled water bath changes between the first and second cycles. The resulting wetting angle of the fibrous material is determined from the arithmetic mean of the measured data over three measurement cycles. The test apparatus shall be operated in accordance with the standardized operating procedure described in the manufacturer's manual.

427 / B

100

Examples

The following examples are provided for the purpose of illustrating the present invention in more detail, and are not intended to limit its scope in any way. In the context of the examples, it should be noted that in various cases, the first primary layer portion 48 may alternatively be referred to as an upper or upper layer, while the second primary layer portion 50 may alternatively be referred to as a lower or lower layer.

Example 1

The wearer-facing absorbent layer has a basis weight of 500 g / cm ² and consists of 50% Dow 53C superabsorbent material marketed by Dow Chemical and 50% HPF2 mercerized pulp marketed by Buckeye Corp. The Dow 53C superabsorbent material exhibits: τ value of 8.5 min .; a FAUZL inundation capacity value of 33 g / g and a MAUL ingestion value of 0.3 psi (2.07 kPa) of 26.2 g / g. This absorbent layer facing the user &apos; s skin extends as can be seen in FIG. 3 and 3A, in the region of the layer portion 48, and is densified to a value of 0.2 g / cm ³ .

The garment-facing absorbent layer has a basis weight of 200 g / cm ² over the area covered by the skin-facing absorbent layer 48 of the wearer, and the remainder of its total extent coincides with the total extent of the absorbent core defined by its shape. configuration (area of the layer portion 50) has a basis weight of 500 g / cm ² . This layer consists of 25% superabsorbent material of the SXM 880 type, marketed by Stockhausen, and 75% wood pulp in the form of a fibrous tuft type CR-1654, marketed by the Alliance Forest Product, based in Coosa Pines, Alabama. The superabsorbent material of the SXM 880 type exhibits: τ 4 min .; a FAUZL inundation capacity value of 38 g / g and a MAL ingestion value of 0.3 psi (2.07 kPa) of 29.8 g / g. This absorbent layer facing the user's laundry extends completely, as can be seen from FIG. 3, over the entire range of the absorbent system (region of the layer portion 50), and is densified to a value of 0.2 g / cm ³ .

427 / B

101

This embodiment has a flow conductivity of 3.24 x ^{10 6} cm @ ³ and a liquid wicking value of 38.3%.

In this exemplary embodiment, either or both of the absorbent layers may be stabilized by cross-linking using a cross-linking agent such as Kymene.

Example 2

The user-facing absorbent layer has a basis weight of 336 g / cm ² and consists of 75% of the Dow 53C type superabsorbent material marketed by Dow Chemical and 25% of the HPF2 type mercerized pulp marketed by Buckeye Corp. The Dow 53C superabsorbent material exhibits: τ value of 8.5 min; a FAUZL inundation capacity value of 33 g / g and a MAUL ingestion value of 0.3 psi (2.07 kPa) of 26.2 g / g. This absorbent layer facing the user &apos; s skin extends as can be seen in FIG. 3 and 3A, in the region of the layer portion 48, and is densified to a value of 0.2 g / cm ³ .

The garment-facing absorbent layer has a basis weight of 300 g / cm ² over the area covered by the garment-facing layer 48 of the wearer, and the remainder of its total extent coincides with the total extent of the absorbent core defined by its shape. configuration (region of the layer portion 50), has a basis weight of 342 g / cm ² . This layer consists of 20% superabsorbent material of the SXM 880 type, marketed by Stockhausen, and 80% wood pulp in the form of a fibrous tuft of the type CR-1654, marketed by Alliance Forest Product, located in Coosa Pines, Alabama. The superabsorbent material of the SXM 880 type exhibits: τ 4 min .; a FAUZL inundation capacity value of 38 g / g and a MAUL ingestion value of 0.3 psi (2.07 kPa) of 29.8 g / g. This absorbent layer facing the user's laundry extends completely, as can be seen from FIG. 3, over the entire range of the absorbent system (region of the layer portion 50), and is densified to a value of 0.2 g / cm ³ .

This exemplary embodiment has a flow conductivity of 4.13 * 10 &quot; cm &^lt; ^{3 &gt;} and a liquid wicking value of 31.6%.

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102

Example 3

The wearer-facing absorbent layer has a basis weight of 502 g / cm ² and consists of 60% Dow 53C superabsorbent material marketed by Dow Chemical and 40% HPF2 mercerized pulp marketed by Buckeye Corp. The Dow 53C superabsorbent material exhibits: τ value of 8.5 min; a FAUZL inundation capacity value of 33 g / g and a MAUL ingestion value of 0.3 psi (2.07 kPa) of 26.2 g / g. This absorbent layer facing the user &apos; s skin extends as can be seen in FIG. 3 and 3A, in the region of the layer portion 48, and is densified to a value of 0.2 g / cm ³ .

The garment-facing absorbent layer has a basis weight of 200 g / cm ² in the area covered by the garment facing layer 48 of the wearer, and the remainder of its total extent coincides with the total extent of the absorbent core defined by its shape. configuration (region of the layer portion 50), has a basis weight of 435 g / cm ² . This layer consists of 25% superabsorbent material of the SXM 880 type, marketed by Stockhausen, and 75% wood pulp in the form of a fibrous tuft of the type CR-1654, marketed by Alliance Forest Product, located in Coosa Pines, Alabama. The superabsorbent material of the SXM 880 type exhibits: τ 4 min .; a FAUZL inundation capacity value of 38 g / g and a MAUL ingestion value of 0.3 psi (2.07 kPa) of 29.8 g / g. This absorbent layer facing the user's laundry extends completely, as can be seen from FIG. 3, over the entire range of the absorbent system (region of the layer portion 50), and is densified to a value of 0.2 g / cm ³ .

This exemplary embodiment has a flow conductivity of 4.99 x 10 cm @ ³ and a liquid wicking value of 31.0%.

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The above values are summarized in the following table:

Example # Flow Conductivity Value (.10'® cm ² ) Absorbency value liquids (%) Comb. conductivity / absorbency value (.10® cm ² ) 1 3.24 38.3 16.0 2 4.13 31.6 14.7 3 4.99 31.0 15.3

Functional application of some commonly used absorbent structures is associated with the requirement of perfect distribution of the acting fluid, while other commonly used absorbent structures require functional absorption of the acting fluid for functional application. Unfortunately, such commonly used absorbent structures are not designed to be capable of providing a combination of said properties, i. both improved aspiration and improved distribution, but which are typically provided by the absorbent structure according to various embodiments and aspects of the present invention. For comparison purposes, Comparative Examples 4 to 8 were prepared, as shown in the following table:

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Pr. # SAP SAP BW top layer (g / cm ² ) Top layer type wood pulp SAP SAP BW Bottom Layer (g / cm ² ) Pulp backsheet Pulp BW (g / cm ² ) Pulp (g / cm ² ) BW 4A SXM 880 CR-1654 SXM 880 CR-1654 215 400 78 232 5A 20/30 SXM 870 CCLC 60/100 SXM 870 CCLC 269 292 529 294 6A SXM 870 CCLC 60/100 SXM 870 CCLC 159 295 319 295 7A 20/30 SXM 870 CCLC 60/100 SXM 870 CCLC 215 281 239 281 8A ON THE CCLC SXM 880 CR-1654 300 250 250

A-Example 4 shows a characteristic embodiment of the absorbent structure described in U.S. Patent No. 5,356,403 to Faulks et al. In this example, the top layer has a density of 0.2 g / cm ³ and the bottom layer has a density of 0.3 g / cm ³ .

B. Examples 5 to 7 show the characteristic embodiments of the absorbent structures described in EP 0 631 768 A1 to Plischke et al. In these examples, both layers have a density of 0.2 g / cm ³ and both layers decompose

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105 throughout the composite absorbent core defined by its shape configuration and described in said patent document.

C. Example 8 shows a characteristic embodiment of the absorbent structure described in US Patent No. 5,360,420 to Cook et al. In this example, the top layer has a density of 0.07 g / cm ³ and the bottom layer has a density of 0.25 g / cm ³ . The shape configuration of both layers is described in detail in the present document.

CCLC is chemically cross-linked cellulose, as described, for example, in U.S. Pat. 4,898,642.

SXM 870 and SXM 880 are superabsorbent materials marketed by Stockhausen under the tradename FAVOR SX. Their optional designation means that they are screened by sieving to the desired particle size, for example: 20/30 mesh (600 to 850 µm), 60/100 mesh (150 to 250 µm).

The superabsorbent SXM 880 exhibits a τ of 4 min; a FAUZL inundation capacity value of 38 g / g; and a MAUL ingestion value of 0.3 psi (2.07 kPa) of 29.8 g / g.

The superabsorbent material SXM 870 has a τ of 4 min; a FAUZL inundation capacity value of 32.5 g / g; MAUL at a load of 0.3 psi (27 psi) of 27 g / g.

The superabsorbent material &quot; 20/30 SXM 870 &quot; a FAUZL induction capacity value of 34 g / g; and a MAUL deviation value of 0.3 psi (2.07 kPa) of 28.8 g / g.

The superabsorbent material &quot; 60/100 SXM 870 &quot; a FAUZL inundation capacity value of 27.5 g / g; and a MAUL ingestion value at a load of 0.3 psi (2.07 kPa) of 23.3 g / g.

The characteristic values exhibited by the absorbent structures of Examples 4 to 8 are shown in the following table:

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Example Flow conductivity value (.10 ⁶ cm ² ) Absorbency value liquid (%) Comb. conductivity / absorbency value (10 ' ⁶ cm ² ) 4 2.9 31.7 13.5 5 6.75 13.3 11.2 6 6.75 13.4 11.2 7 6.68 20.8 13.6 8 1.4 35.2 13.1

As may be apparent from the above, neither absorbent structure of the Comparative Examples is able to provide the combination of desirable characteristics provided by the absorbent structure of the present invention.

From the foregoing detailed description of the specific embodiments of the present invention, it will be apparent to those skilled in the art that various variations and modifications may be made thereto without departing from the spirit of the invention, all such variations being made. and modifications falling within the scope of the present invention as defined in the appended claims.

Claims (24)

PATENT CLAIMS An absorbent article comprising: a backsheet, a substantially liquid-permeable topsheet, a composite absorbent structure sandwiched between said backsheet and topsheet layers, the composite absorbent structure comprising an absorbent core having a first primary ply and a second a primary layer portion, the second primary layer portion having a uniform, selectively distributed zonal basis weight, and at least one of said first and second primary layer portions having a liquid wicking value of at least about 36%. The absorbent article of claim 1, wherein the absorbent core has a dry-state thickness of no more than about 6 mm and a minimum crotch region width of no more than about 10 cm. The absorbent article of claim 1, wherein it is user-configured for adults and the absorbent core has a dry-state thickness of no more than about 6 mm and a minimum crotch region width of no more than about 14 cm. . The absorbent article of claim 1, wherein the absorbent core has a combined conductivity / absorbency value of at least about ¹⁴ x ^{10 6} cm ³ . The absorbent article of claim 1, wherein the absorbent core has a dry state thickness of no more than about 6 mm and a minimum crotch region width of no more than about 10 cm. 31,427 / B 108 The absorbent article of claim 1, wherein the first primary layer portion is disposed on the skin facing the user side of the composite absorbent structure and the second primary layer portion is disposed outwardly relative to the first primary layer portion. 7. An absorbent article according to claim 1 wherein at least one of the primary sheet portions comprises a superabsorbent material having a modified absorbency value at a load of at least about 20 g / g. The absorbent article of claim 1, wherein at least one of the primary sheet portions comprises a superabsorbent material having a Tau time characteristic value of not less than about 0.8 min. An absorbent article comprising an absorbent core having a first primary layer portion and at least a second primary layer portion, wherein the absorbent core has a length in the longitudinal direction, a width in the transverse direction, and a predetermined upstream end edge that the first primary layer portion has a base a weight of not less than about 100 g / m ² and not more than about 700 g / m ² that the first primary layer portion has a density of not less than about 0.03 g / m ³ and which is not is greater than about 0.4 g / m ³ that the first primary layer portion comprises fibrous material in an amount of not less than about 25 wt. and which is not greater than about 80% by weight, said fibrous material comprising fibers having a diameter of not less than about 4 µm and not greater than about 20 µm, wherein said first primary layer portion comprises superabsorbent material in an amount, %, which is not less than about 50 wt. and which is not more than about 80% by weight, that the superabsorbent material comprises particles having a size of not less than about 110 µm and not more than about 1000 µm, 31,427 / B 109 that the superabsorbent material exhibits a modified MAUL absorbency value of not less than about 20 g / g, and that the superabsorbent material has a Tau time value of not less than about 0.8 min. 10. An absorbent article according to claim 9, wherein the first primary layer portion is substantially adjacent each other to the lateral end edges of the second primary layer portion, and wherein the first primary layer portion is disposed in a zone that begins with a transversely extending line spaced apart. about 7% of the total length of the absorbent core inwardly from the foremost end edge of the absorbent core and extends to a second transverse extending line spaced about 62% of the total length of the absorbent core inwardly from said frontmost end edge of the absorbent core. The absorbent article of claim 10, wherein the first primary layer portion comprises a binder material. The absorbent article of claim 9, wherein the first primary layer portion comprises a plurality of sub-layers. The absorbent article of claim 9, wherein the second primary sheet portion has a longitudinal extent greater than the first primary sheet portion in a longitudinal direction, and wherein the second primary sheet portion has a transverse extent that substantially borders on the extent of the first primary layer portion in the transverse direction. 31,427 / B 110 14. An absorbent article according to claim 9 wherein the second primary layer portion has a longitudinal extent greater than the first primary layer portion in a longitudinal direction, wherein the second primary layer portion has a transverse extent that is smaller. as the extent of the first primary layer portion in the transverse direction, and that the extent of at least a portion of the second primary layer portion in the transverse direction is not less than about 30% of the extent corresponding to the adjacent portion of the first primary layer portion in the transverse direction. An absorbent article according to claim 9, wherein the second primary layer portion has a range in the longitudinal direction that is greater than the extent of the first primary layer portion in a longitudinal direction, the second primary layer portion has a range in the transverse direction that is greater as the extent of the first primary layer portion in the transverse direction and that the extent of at least a portion of the first primary layer portion in the transverse direction is not less than about 30% of the extent corresponding to the adjacent portion of the second primary layer portion in the transverse direction. An absorbent article according to claim 9, wherein the receiving zone of the second primary sheet portion has a basis weight that is less than the basis weight of the remainder for receiving an unspecified portion of the second primary sheet portion. 17. An absorbent article according to claim 9 wherein the acquisition zone of the second primary sheet portion has a basis weight of not less than about 100 g / m &lt; ² &gt; and not more than about 250 g / m &lt; ² &gt; the portion of the second primary layer portion has a basis weight of not less than about g / m ² and not greater than about 550 g / m ² . 31,427 / B 111 The absorbent article of claim 17, wherein the second primary layer portion has a density of not less than about 0.1 g / m ³ and no greater than about 0.3 g / m ³ , wherein the second the primary layer portion comprises fibrous material in an amount of not less than about 50 wt. and which is not greater than about 95 wt.%, said fibrous material comprising fibers having a diameter of not less than about 4 µm and no greater than about 20 µm, said fibrous material comprising fibers having a water wetting angle. not more than about 70 degrees, the second primary layer portion contains superabsorbent material in an amount of not less than about 5 wt. and which is not more than about 50 wt. and that the superabsorbent material comprises particles having a dry state size of not less than about 110 µm and not more than about 1000 µm. 19. An absorbent article according to claim 18 wherein the superabsorbent material contained in the second primary sheet portion has a modified MAUL absorbency value of not less than about 20 g / g and a Tau time value of at least about 0. 4 minutes. 20. An absorbent article according to claim 19 wherein the superabsorbent material contained in the second primary sheet portion is configured as a sandwich layer sandwiched between the paper layers. 21. The absorbent article of claim 20 further comprising a backsheet and a substantially liquid-permeable topsheet configured to have an absorbent core sandwiched between the layers. 31,427 / B 112 22. An absorbent article according to claim 21 wherein the absorbent core has a flow conductivity of at least about 7.10 &lt; ^{6 &gt;} cm &lt; ^{3 &gt;} and at least one of said first and second primary sheet portions has a liquid wicking value of at least about 16%. 23. The absorbent article of Claim 22 wherein at least one of said first and second primary sheet portions has a liquid wicking value of at least about 36%. The absorbent article of claim 22, wherein the second primary layer portion comprises a binder material.