MXPA97008244A - Composite fabric non-woven of type tram - Google Patents

Abstract

The present invention relates to a washable composition comprising: a) a first filamentous layer, said first layer comprises crimped continuous filaments, b) a second filamentous layer, said second layer comprises crimped continuous filaments, and c) a cellulosic layer, said layer cellulosic comprises cellulosic fibers and is positioned between the first and second filamentous layers, wherein said compound is a compound bound with hydroentangled pattern that is joined with an adhesive pattern or thermally forming regions bound within said compound, and said compound loses less than about 2% of its opacity, based on the initial opacity of said compound, when subjected to a washing cycle according to the washing and drying process ASTM 2724-87 and wherein said first and second filamentary layers are not joined except by of said adhesively or thermally formed joints with patr

Description

COMPOSITE FABRIC NON-WOVEN OF TYPE TRAMADO BACKGROUND OF THE INVENTION The present invention relates to a hydroentangled and durable nonwoven composite fabric containing pulp fibers and continuous filaments.

Hydroentangled processes and hydroentangled composite fabrics containing various combinations of different fibers are known in the art. A typical hydroentanglement process uses high pressure water jet streams to entangle the fibers and / or filaments to form a highly entangled consolidated fibrous structure, for example, a non-woven fabric. Non-woven hydroentangled fabrics of stable-length fibers and continuous filaments are described, for example, in U.S. Patent Nos. 3,494,821 issued to Evans and 4,144,370 issued to Bouolton. Non-woven composite hydroentangled fabrics of a continuous filament nonwoven fabric and a pulp layer are described, for example, in U.S. Patent Nos. 5,284,703 and 4,808,467 issued to Suskind et al. The non-woven fabric of high pulp content of the United States of North America No. 5,284,703 is strong and resistant to abrasion and also has a high capacity to absorb aqueous liquids and oils, making the fabric highly suitable, for example , heavy duty cleaning applications.

The hydroentangled composites of the prior art are suitable for various uses, are typically adapted for non-multiple use disposable applications and are designed to be non-washable. When the hydroentangled compounds are machine washed, they tend to release significant amounts of the component fibers and to form bulked lumps or fibers, forming compounds having a highly non-uniform fiber coverage. There is still a need for durable hydroentangled composites that can be used in multiple wash and use applications.

SYNTHESIS OF THE INVENTION The present invention provides a washable and durable hydroentangled compound that is patterned. The composite contains two layers of filament fabric containing crimped continuous filaments and a cellulose layer containing cellulosic fibers. The cellulosic layer is placed between the layers of filament fabric. The composite fabric is washable as demonstrated by the fact that the compound loses less than about 2% of its opacity, based on the initial opacity of the compound, when it is subjected to a wash cycle according to the washing procedure and dried ASTM 2724-87.

A process for forming the durable composite fabric is additionally provided. The process has the steps of providing a layered structure having a first filamentous layer of crimped filaments, a second filamentous layer of crimped filaments and a cellulosic layer positioned between the first and second filamentous layers; hydroentangling the layered structure to form a bonded laminate and bonding the laminate attached to form the composite, wherein the composite loses less than about 2% of its opacity, based upon the initial opacity of the composite, when subjected to a Washing cycle according to the AST washing and drying process 2724-87.

The composite fabric is highly suitable for use in skin contact applications, since the fabric has soft cloth-like texture and visual properties and is absorbent and breathable.

The term "washable" is used herein to mean that a compound is subjected to at least one cycle comprised of washing machine and drying process in accordance with ASTM 2724-87. The change in the uniformity of the compound is measured by the change in the opacity of the compound. Opacity is measured by a "contrast ratio" method based on the observation that the reflectance of a fabric when combined with a white backing is superior than when it is combined with a black backing. This method measures the color values of a given fabric using a tristimulus colorimeter with an "A" type sensor and the lighting provided by a C CIÉ Standard source (simulated cloudy sky light), such as the Hunter D25A-9, D25APC2 or D25DP9000 laboratory model from Hunter Associates Laboratory, Reston, Virginia. The instrument is standardized with white (89% reflectance) and black (100% absorbency) tiles. The specimen is then placed on the optical sensor and the color values relative to the perfect white diffuser are noted. The decrease in the opacity value indicates that parts of the fibers of the fabric are lost or rearranged, indicating that the fabric developed a non-uniform fiber covering and / or perforations. Opacity measures the level of light that is prevented from being transmitted through the test specimen compound. Consequently, the level of decrease in opacity measures the level of thinned sections and / or holes that developed in the composite during the wash cycle.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates an exemplary process for producing the durable compound of the present invention.

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a washable and durable non-woven composite fabric that exhibits cloth-like visual, absorbent and texture properties, more particularly cotton-like fabric properties. The durable nonwoven composite has at least two layers of crimped continuous filament fabric and at least one layer of cellulosic material, and the composite contains, based on the total weight of the composite, between about 40% and about 85% desirably between about 50% and about 80%, more desirably between about 60% and about 75%, of the filamentous fabric layers; and between about 60% and about 15%, desirably between about 50% and about 20%, more desirably between about 40% and about 25%, of the cellulosic layer. The present compound is soft, has a fall, is durable and washable, as well as being liquid-absorbent and breathable. In addition to these useful properties, the composite provides limited recovery and stretch characteristics that are akin to a woven cotton fabric, making the composite highly suitable for human skin contact applications. Exemplary products that can be produced from a durable composite include T-shirts, underwear, sleepwear, parts for various disposable items, e.g., diapers, training pants, sanitary napkins, garments and protective cloths, and the like.

Unlike the hydroentangled compounds of the prior art, the compound of the present invention retains uniform fiber coverage and does not lose a significant amount of its component materials, particularly cellulosic fibers, when the compound is machine washed and machine dried. typical commercial or domestic washing and drying. In general, the loss of the component materials can be measured in weight loss of the compound, and the present compound loses no more than 5% by weight, desirably no more than 3% by weight, more desirably no more than about 2% by weight, based on the weight of the initial compound, per wash cycle. As indicated above, the loss of uniform fiber coverage can be measured in the deterioration of the opacity of the compound, and the present compound has a decrease in opacity of less than about 2%, desirably less than about 1.5% , more desirably less than 1%, based on the opacity of the initial compound, per wash cycle, more desirably, the opacity of the compound is not decreased by the wash cycle.

Suitable fabric materials for each of the filamentous fabric layers of the present invention include non-bonded webs of continuous and crimped filaments having a basis weight of between about 15 grams per square meter (gsm) and about 50 gsm. per square meter, desirably between about 20 gsm and about 35 gsm. It has been found that continuous and crimped filaments have a filamentous structure that is particularly suitable for producing the hydroentandered compound of the present invention. The term "unbonded web" as used herein refers to a non-bonded fabric or an engraved web of continuous filaments. The term "engraving" as used herein indicates having consolidated regions that are imparted on a filamentary fabric to facilitate proper handling, for example, carrying and transporting the fabric. The engraved regions of the filamentous fabric must be pulled and separated and broken by the application of the jet streams of the hydroentanglement process, allowing the filaments to have a freedom of movement and ensuring an adequate entanglement of the filamentous fabric layers and the filament layer. cellulose layer. Consequently, an etching process provides regions of temporary consolidation in the filamentary fabric while a bonding process provides permanent interfiber bonding or cohesion regions. The term "continuous filaments" as used herein indicates filaments having a length equal to or longer than about 15 cm, for example, significantly larger than conventional short fibers. More desirably, the continuous filaments have a length that is long enough to cover the entire length of the filamentous fabric. Filamentous fabrics of continuous and crimped filaments can be produced from any fiber-forming thermoplastic polymers. Suitable filaments are one component filaments of ur. thermoplastic polymer or a mixture of more than one of the thermoplastic polymers. The additionally suitable filaments are multi-component conjugated filaments containing at least two component polymers which occupy different cross-sections of the filament along substantially the entire length of the filament and of the multicomponent filaments containing discrete fibrils of one or more component polymers within a filamentous polymer matrix.

Suitable thermoplastic polymers for continuous filaments include polyolefins, polyesters, polyamides and copolymers and mixtures thereof. Suitable polyolefins for conjugated fibers include polyethylene, for example, high density polyethylene, medium density polyethylene, low density polyethylene and linear low density polyethylene. Polypropylene, for example, isotactic polypropylene, syndiotactic polypropylene, mixtures thereof, and mixtures of isotactic polypropylene and atactic polypropylene; polybutylene, for example, (poly (I-butene) and poly (2-butene); polypentene, for example, poly (l-pentene) and poly (2-pentene); poly (3-methyl-1-pentene) poly (4-methyl-1-pentene), and copolymers and mixtures thereof Suitable copolymers include block and random copolymers prepared from two or more different unsaturated olefin monomers, such as ethylene / propylene and copolymers of ethylene / butylene Suitable polyamides for conjugated fibers include nylon 6/6, nylon 4/6, nylon 11, nylon 12, nylon 6/10, nylon 6/12, nylon 12/12, copolymers of caprolactam and diamine oxide alkylene and the like, as well as mixtures and copolymers thereof Suitable polyesters include polyethylene terephthalate, polybutylene terephthalate, polytetramethylene terephthalate, polycyclohexylene-1,4-dimethylene terephthalate, and isophthalene copolymers of the themselves, as well as mixtures thereof, of course suitable polymers, more desirably the polymers are polyolefins, more desirably polyethylene and polypropylene, because of their commercial availability and their importance, as well as their chemical and mechanical properties.

Suitable filaments for the present composite have at least about two crimps per extended inch, desirably between about 2 and about 50 crimps per extended inch, more desirably between about 3 and about 30 crimps per extended inch, as it is measured in accordance with ASTM D-3937-82. Desirably, the crimps are helical crimps. Curls in the filaments may be imparted during the filament spinning process or after the filaments are fully formed or by selecting a polymer composition or polymer compositions having a spontaneous rizabilidata when they are processed into filaments.

The curls in the conjugated monocomponent filaments can be imparted by mechanically crimping the fully formed filaments. As is known in the art, mechanical crimping devices, including crimpers and tow boxes, can be used to impart the crimps. Alternatively, crimps in the filaments, especially the polypropylene-containing filaments can be imparted during the filament spinning process by asymmetrically cooling the filaments across the cross-section while the spun filaments are being pulled and solidified. Such an asymmetric cooling process generates a differential contraction within the cross section of the spinning filaments, causing ripples there.

Still another process for curling filaments is highly suitable for conjugated filaments. This process uses the latent rizability of the conjugated filaments. When the component polymers for the conjugated filaments are selected to have different crystallization and / or shrinkage properties, the resulting filaments contain urine latent heat-activatable curing. The crystallization / shrinkage disparity between the component polymers of the conjugated filaments, which may result from further crystallization and densification or from the relaxation of the residual stresses, causes the filaments to become rippled when the component polymers of the filaments they are allowed to crystallize or relax additionally. Exemplary processes for producing highly suitable conjugated fibers having such latent rizability and the filamentous nonwoven fabrics produced therefrom are described in commonly assigned United States Patent No. 5., 382,400 granted to Pike and others, which is hereby incorporated by reference in its entirety. Although U.S. Patent No. 5,382,400 discloses spun-bonded filament fabrics, filamentous fibers suitable for the present invention are obtained when the binding step described herein is omitted. Suitable polymers for multi-component conjugate filaments are selected from the thermoplastic polymers listed above. For example, for conjugated two-component filaments (bicomponent filaments) suitable pairs of polymers include polyethylene-polypropylene, polyethylene-polyamide, polyethylene-polyester, polypropylene-polya ida, polypropylene polyester, and the like. More specifically, desirably suitable pairs include high density polyethylene-propylene, low density polyethylene-polypropylene, high density polyethylene-nylon 6, high density polyethylene-nylon 6/6, polyethylene-nylon 6 low linear density, polyethylene-nylcn 6/6 linear low density, high density polyethylene-polyethylene terephthalate and linear low density polyethylene-polyethylene terephthalate.

Suitable continuous crimped filaments have an average diameter of between about 10 μm and about 50 μm, desirably between about 15 μm and about 30 μm. The continuous filaments may have a cross-sectional configuration other than conventional circular shapes, for example, a bilobal, trilobal, rectangular or oval configuration.

According to the present invention, various woody and non-woody pulps and other cellulosic fibers can be incorporated into the composite as the cellulosic layer, and the pulps can be a mixture of different types and / or qualities of pulp fibers. However, wood pulps of long flexible fibers having a low roughness index are more useful for the cellulosic layer of the present invention. Illustrative examples of suitable pulps include the kraft pulp of soft northern wood, southern pine, red cedar, spruce, eucalyptus, black spruce and mixtures thereof. Commercially available examples of long pulp fibers suitable for the present invention include those available from Kimberly-Clark Corporation under the trade designation Longlac-19, Coosa River-54, Coosa River-56 and Cocsa River-57. The cellulosic layer may also contain a smaller amount of hydrophilic synthetic fibers, for example, rayon fibers and ethylene vinyl alcohol copolymer fibers, and hydrophobic synthetic fibers, for example, polyolefin fibers. Desirably, the cellulosic layer has a basis weight of between about 10 grams per square meter and about 50 grams per square meter, more desirably between about 15 grams per square meter and about 30 grams per square meter.

Referring to Figure 1, there is illustrated a process 10 for producing a durable woven-type composite of the present invention. A diluted suspension of pulp fibers in water is supplied by a head box 12 and is deposited through a conduit 14 in a uniform dispersion on a forming fabric 16 of a papermaking machine, and then the water is removed from the suspension to form a uniform cellulosic layer of pulp fibers 18. The suspension can be diluted to any consistency that is typically used in a conventional papermaking process. For example, the suspension may contain from about 0.1% to about 1.5% by weight of pulp fibers suspended in water. Alternatively, the cellulosic layer 18 can be separately preformed into a sheet or roll of pulp fibers.

The cellulosic layer 18 is then placed between two layers of crimped filamentary fabrics 24 and 26 which are unwound from the supply rolls 28 and 3, respectively, to form a unitary composite structure 32. Even when Figure 1 illustrates that the layers of cloth 24 and 26 are preformed, the fabric layers can be produced in line.

As discussed above, the fabric layers are unbonded or engraved fabrics of curled continuous filaments. The composite structure 32 is then placed on a foraminous entanglement surface 34 of a hydroentanglement machine.

The composite structure 32 is treated with fluid jets, typically water, to entangle the layers of the composite. Hydroentanglement processes are known in the art, and for example, US Pat. No. 3,485,706 issued to Evans describes a suitable hydroentanglement process, the patent of which is incorporated herein by reference. The invention can also be practiced, for example, by using a manifold 36 produced by Honeycomb Systems Incorporated, of Biddeford, Maine, containing a fiber having 0.18 millimeter diameter holes, 12 holes per centimeter and a row of holes. A working fluid, typically water is passed through the orifices at a pressure varying from about 14 to about 140 kilograms per square centimeter meter, desirably from about 35 to 130 kilograms per square centimeter meter. The working fluid sticks to the compound 32, which is supported by the foraminous surface 34 and causes the complete entanglement and interlock of the crimped filaments of the filamentous fabric layers and the pulp fibers of the cellulosic layer. The hydroentanglement process can employ a vacuum apparatus 38, which is positioned directly below the foraminous surface 34 where the hydroentanglement manifold 36 is located, so that the working fluid is removed from the hydroentangled compound 40. The foraminous surface 34 may be of a variety of sizes and configurations including a single plane mesh having a deeie mesh size of about 10 x 10 to about 100 x 100 or a multiple mesh having a mesh size of around 5C x 50 to around 200 x 200.

Although Figure 1 illustrates that the hydroentanglement process is applied from only one side of the compound, it is more desirable to apply the hydroentangling process on both sides of the compound to produce a compound having essentially indistinguishable sides. The hydroendedean process can also be used to impart a pattern effect that creates perforations in the fabric, for example, as described in United States Patent No. 3,033, -21 issued to Kalwaites.

After hydroentanglement of compound, compound 40 is dried. Desirably, the compound is dried without applying compression. The compound can be dried using, for example, a dryer apparatus through the rotating drum air 42. The drying apparatus 42 has an outer perforated surface that holds the composite and allows the heated air to go through the perforated surface to the compound, removing residual working fluid and moisture from the compound.

According to the present invention, the dried hydroentangled compound is patterned to form uniformly or substantially uniformly distributed regions, imparting durability and possibility of washing as well as imparting additional desirable texture properties, eg, woven and woven type textures , without significantly changing the physical properties, such as the drop and softness, of the hydroentangled compound. The phrase "bound regions" distributed in an essentially uniform manner as used herein indicates that the joined regions may not be distributed in a perfectly uniform manner but are not crowded together to form large unbound regions. More particularly, the phrase "substantially uniformly distributed linked regions" indicates that the distance between the adjacent joined regions of a bound compound is not greater than 10 times, desirably not greater than 5 times, the width of the largest dimension of the regions united. Suitable bonding methods include autogenous bonding processes and adhesive bonding processes. More desirably the binding processes for the present invention. they are autogenous joining processes since the unicr processes. autogenous do not require additional materials, for example, foreign adhesives, and production steps, for example, steps of adhesive application and setting. In general, an autogenous pattern joining process employs pairs of pattern-bonding rolls, eg, 44 and 46 of Figure 1, to effect bound regions distributed substantially uniformly in limited areas of the compound by passing the compound through through the clamping point formed by the connecting rollers. One or both of the pair of rollers are heated to an appropriate temperature and have a pattern of plains and pressures on the surface, which affects the joined regions. Alternatively, the bonding pattern may be applied by passing the fabric through a gap formed by an ultrasonic working horn and an anvil.

The temperature of the bonding rollers and the pressure of the attachment point should be selected so as to effect the joints without having undesirable accompanying side effects such as fabric degradation. In addition, the temperature of the bonding roller should not be so high as to cause the fabric to stick to the bonding rolls. Stated otherwise, it is not desirable to expose the fabric to a temperature at which the polymer of the fabric layers melts excessively, thereby thermally degrading the fabric and allowing the fabric to stick to the bonding rolls. Although roller temperatures and appropriate clamping point pressures are generally influenced by parameters such as the speed of the fabric, the basis weight of the fabric, the component polymers and the like, the temperature of the roll is desirably in the range between the softening point and the crystalline melting point of the component polymer that forms the filaments. For example, the desirable binding roll fittings for a layer of fabric containing polypropylene filaments are a roll temperature in the range of about 125 ° C and about 160 ° C and a pressure point of bonding on the fabric in the range of about 350 kilograms / square centimeter and about 3500 kilograms / square centimeter. For a layer of filamentous fabric containing linear low density polyethylene, the proper temperature of the bonding roll is between about 120oC and about 135oC. A suitable laminate bonding process is described in United States Patent No. 4,041,203 issued to Brook et al., Which is incorporated herein by reference.

Adhesive-bonding processes suitable for the present invention effect discrete joined regions uniformly distributed or substantially uniformly distributed using an adhesive. The proper adhesives included. materials of natural and synthetic polymer latex, such cor.:. Rhoplex® E-940 and Rhoplex® NW-1715, which are available from Rohm and Haas, and Elastoplast® V-29 which is available from B.F. Goodrich. The latex material is desirably applied to the dry hydroentangled compound as an aqueous solution. The method of application is not critical and is largely a matter of convenience. Therefore, the latex solution can be applied by a sprayer, a brush, a roller or setter, provided that the selected application method can deliver the latex solution to discrete pre-defined regions in the compound. Desirably, the adhesive is applied on both sides of the compound. After the solution of the latex is applied to the compound, the compound is dried, desirably at an elevated temperature to remove the water and to set the latex.

According to the present invention, the total area covered by the thermally or adhesively bonded regions occupies between about 10% and 50%, desirably about 15% to about 45%, more preferably about 20% to about 35% , of the planar surface of the compound. Suitable bonding patterns include knit patterns of various shapes, such as circles, diamonds, rectangles, squares, ovals and the like; and the line joining patterns of various configurations, such as straight lines, waves, curves and the like. Desirably, when a grease bonding pattern is employed, the bound compound contains from about 10 to about 250 bonding points per square centimeter (cm2), more preferably from about 42 to about 234 points joined per centimeter square.

The durable and washable composite of the present invention exhibits physical and fabric-like texture properties of cotton. The composite is highly suitable for various uses including clothing, protective garments, cloths, covers and the like. The composite is more particularly suitable for skin contact applications such as underwear, cleansers, bed liners, disposable article parts such as such as diapers and sanitary napkins, and the like.

The following examples are provided for purposes of illustration and the invention is not limited thereto.

Examples: The following test procedures were used to evaluate the test specimens of the examples: Weight Loss The weight loss of the hydroentangled compound is attributable to the pulp fibers of the cellulosic layer that are unraveled and separated from the compound during the washing process. Weight loss is the difference between the weight of the compound before washing and the weight of the compound after washing.

Volume The lower the increase in volume, the more stably the pulp fibers and the filaments in the composite are fixed. The volume was measured using a thickness tester Ames, Model 3223 equipped with a graduation indicator of 0.001 inches. A three-inch-diameter plate with a total weight of 0.4 pounds including a tie rod and weights was placed on a 4-inch by 4-inch mix and the volume was read as close as 0.001 inches.

Opacity Opacity was measured according to the test procedure described above.

Comparative Example 1 The following comparative example was carried out to illustrate the importance of the crimps in the filaments forming the filament layer. A nonwoven web bonded nonwoven fabric having a basis weight of 71 g / m2 (gsm) was prepared from 3% ethylene-97% propylene copolymer, which was an Exxon 9335 copolymer, in accordance with U.S. Patent No. 3,802,817 issued to Matsuki et al. The nonwoven fabric was then placed on the hydroentanglement surface of the hydroentanglement apparatus which is illustrated in Figure 1 and hydroentangled. The entanglement foraminous surface had a size of 100 meshes and the multiples had a row of holes of 0.006 inches (0.15 mm) in diameter at a density of 40 holes per inch (16 holes / cm). The energy, more specifically the impact value of energy times (energy-impact), used to hydroentangle the fabric was around 1.5 megaJoule-Newton per kilogram (MJ-N / kg) as calculated according to the product of impact-energy that is described in United States Patent No. 5,023,130 issued to Simpson et al. The description of the energy-impact value described in U.S. Patent No. 5,023,130 is incorporated herein by reference.

The non-crimped and hydroentangled filamentous fabric did not have a uniform and high level of interfiber entanglement and was not well entangled to provide an easily manageable fabric.

The hydroentangled fabric did not easily separate from the entanglement surface.

Example 1 Comparative Example 1 was repeated, except that the filaments of the unbonded web were crimped during the spinning process by applying an asymmetric application of cooling air on the spun filaments just below the spinner member. The resulting unbound fabric had a basis weight of 77 grams per square meter. The fabric was then hydroentangled according to the procedure delineated in Comparative Example 1, except that the energy-impact value used was around 1.38 MJ-N / kg. The hydroentangled crimped filamentary fabric had a uniform and high level of interfiber entanglement, and the hydroentangled fabric easily separated from the entanglement surface.

The hydroentangled fabrics of the two examples mentioned above clearly demonstrate that the curls in the filaments are very important for the adequate hydroentanglement of the filamentous fabrics.

Comparative Examples 2-4 Comparative Examples 2-4 were carried out to demonstrate the short service life of the hydroentangled compounds of the prior art that are produced from a bonded filamentous nonwoven fabric.

Comparative Example 2 (C2) A non-woven fabric joined by crimped and unbonded yarn having a basis weight of 22 g / m2 (gsm) was prepared from a side-by-side bicomponent filament of 50% by weight of linear low density polyethylene (LLDPE) and 50% by weight. % by weight of polypropylene (PP) using the bicomponent conjugate fiber production process described in the aforementioned U.S. Patent No. 5,382,400. The LLDPE, Aspun 6811A, which is available from Dow Chemical, was mixed with 2% by weight of a TiO2 concentrate containing 50% by weight of TiO2 and 50% by weight of a PP, and the mixture was fed into the a first single screw extruder. The PP, class 3445, which is available from Exxon, was mixed with 2% by weight of the Ti02 concentrate described above, and the mixture was fed into a second single screw extruder. The extruded polymers were spun into bicomponent fibers using a side-by-side bicomponent spinning die, which had a spin hole diameter of 0.6 mm and a L / D ratio of 6: 1. The temperature of the melted polymers fed into the spinning die was maintained at 230 ° C and the production rate of the spin hole was 0.5 grams / hole / minute. The bicomponent fibers exiting the spinning matrix were cooled with an air flow having a flow rate of 0.5 m3 / min / cm (45 cubic feet / min / inch) of spinner organ width and a temperature of 18 ° C . The cooling air was applied about 13 cm below the spinning organ. The cooled fibers were pulled into a suction unit of the type described in U.S. Patent No. 3,802,817 issued to Matsuki et al., And the suction air temperature was around 177 ° C. The measurement of the weight-per-length of the pulled fibers was around 2 denier per filament. The drawn fibers were then deposited on a foraminous forming surface to form a non-bonded fiber cloth with the aid of a vacuum apparatus which was placed below the forming surface. The filaments had between 2 and 10 crimps / cm.

The fabric joined by unbound yarn is joined by passing the fabric through the clamping point formed by a calendering roller and an anvil roller. The calendering roll was a steel roll which had a wire wave pattern of regularly spaced dots on its surface and which was equipped with heating means. The anvil roller was a smooth stainless steel roller and was also equipped with heating means. Both of the connecting rolls had a diameter of about 61 cm. The pressure of the bonding bolt applied by the bonding rolls on the fabrics was around 560 kg / cm2 and the rolls were heated to a temperature as indicated in Table 1. The total bonded area of the fabric was about 20% of the total surface area, and each joint had an oval shape of about 0.4 mm in width and 0.85 mm in length.

The bonded non-woven fabric was placed on the hydroentanglement surface of the hydroentanglement apparatus illustrated in Figure 1, and a layer of a preformed tissue sheet of 15 grams per square meter, which contained 50% by weight of eucalyptus fibers and 50% by weight of Longlac-19 fibers, was placed on the non-woven fabric. The compound was hydroentangled according to Example 1, with the pulp layer facing the jet stream of the hydroentanglement manifold. The energy impact value used to hydroentangle the compound was around 0.41 MJ-N / kg. The hydroentangled compound was dried, and tested for its weight, volume and opacity. The volume was then subjected to a washing cycle and drying steps in accordance with the procedures outlined in ASTM 2724-87. The washed compound was then tested for its weight, volume and opacity. The results are shown in Table 1.

Comparative Example 3 (C3) A non-woven bicomponent filament non-woven fabric of 34 grams per square meter was prepared following the procedure outlined in Comparative Example 2. Then the unbonded fabric was joined by passing the fabric through a through-air binding device. which was equipped with a heated air source. The temperature of the heated air was 262 ° F (128 ° C). The residence time of the fabric on the cover was around 1 second. The resulting bonded fabric had interfiber joints at the points of cross contact of the filaments through the fabric.

The nonwoven fabric bonded through air was hydroentangled with a layer of a tissue sheet of 34 grams per square meter of the type described in Comparative Example 2 according to the procedure outlined in Comparative Example 2 except that the energy value -impact used was around 0.28 mJ-N / kg. The resulting hydroentandered compound was tested for its physical properties, washed and then tested for its physical properties according to Comparative Example 2. The results are shown in Table 1.

Comparative Example 4 (C4) A hydroentangled compound was produced according to Comparative Example 2 except that an additional bicomponent filament spunbonded layer was placed on the pulp layer. The impact-energy value used was around 0.51 MJ-N / kg. Both sides of the composite were subjected to the hydroentanglement process in order to produce a hydroentanglement compound having two sides having equal texture and visual properties. The additional tie layer had the same composition and base weight of the spunbonded layer described in Comparative Example 2. The resulting hydroentangled composite was tested for physical properties, washed and then tested for its physical properties. according to Comparative Example 2. The results are shown in Table 1.

Example 2 (Ex2) An unwoven fabric bonded by unbonded yarn of 34 grams per square meter and an unbonded nonwoven fabric of 27 grams per square meter of crimped bicomponent filaments and a pulp sheet of 30 grams per square meter was produced from according to Comparative Example 4, except that the energy-impact value used was around 0.45 MJ-N / kg. A compound of 34 grams per square meter of non-woven fabric / 30 grams per square meter of tissue layer / 27 grams per square meter of non-woven fabric was prepared and then hydroentangled according to Comparative Example 4, hydroentangled both sides of the compound. The hydroentangled compound was dried and then patterned using a pair of smooth anvil bonding rolls and a pattern roller. The pattern roller had a total bond area of about 20%, and each bonding point had an oval shape of about 0.04 mm in width and a length of 0.025 mm. The roller temperature was 115oC. The anvil was maintained at 117oC, and the compound was advanced to 25 feet / minute (7.6 m / min). The bound composite had soft cotton fabric type visual and texture properties.

The hydroentangled bound composite was tested for physical properties, washed and then tested for physical properties according to Comparative Example 2. Additionally, the compound was subjected to 5 washing and drying cycles and then tested. The results are shown in Table 1.

Example 3 (Ex3) Example 2 was repeated except that the bonding roller had a bonding pattern of lines placed parallel in the machine direction. The union lines had a width of 0.25 millimeters and the total area of the joined regions was around 20%. Again, the compound had cloth-like properties, specifically cotton-like type. The bound compound was tested for its properties, and then washed. The washed compound was tested again for its properties. The results are shown in Table 1.

Comparative Example 5 (C5) A non-bound hydroentandered compound, for example, a hydroentangled but not bound compound produced in Example 2 was tested for its properties, and then washed. The washed compound was again tested in relation to its properties. The results are given in Table 1.

Example 4 (Ex4) Example 2 was repeated except that a lower weight basis pulp layer was used. The pulp layer had a basis weight of 15 grams per square meter, and the energy impact value used to hydroentangle the compound was around 0.53 MJ-N / kg. The results are shown in Table 1.

Example 5 (Ex5) Example 4 was repeated, except that the binding pattern of Example 3 was used. The tissue layer had a basis weight of 15 grams per square meter. The results are shown in Table 1.

Comparative Example 6 (C6) An unbound hydroentangled compound produced in Example 4 was tested for its physical properties, and then washed. The washed compound was again tested for its physical properties. The results are shown in Table 1.

Example 6 (Ex6) Example 4 was repeated except that both layers of bicomponent filament fabric had a basis weight of 27 grams per square meter and the energy-impact value used was 0.89 MJ-N / kg. The results are shown in Table 1.

Example 7 (Ex7) Example 6 was repeated except that the binding pattern of Example 3 was used to bind the compound. The results are shown in Table 1.

Comparative Example 7 (C7) An unbound hydroentangled compound produced in Example 6 was tested for its physical properties, and then washed. The washed compound was again tested for its physical properties. The results are shown in Table 1.

Example 8 (Ex8) A hydroentangled compound was produced according to Example 6, except that the energy-impact value used was around 0.86 MJ-N / kg. The compound was adhesively bonded using a latex, Nacrylic X-8404 from National Starch, thickened with Rhoplex ASE-95 by Rohm and Hass. The latex was applied to the composite by a groove impression method to form discrete oval junctions having dimensions of approximately 6 mm on the main axis and 3 mm on the minor axis. The total union area was around 22%. About 8% by weight of solid equivalent of latex, based on the weight of the compound, was applied on each side of the compound, and the latex was forged in an infrared oven. The results are shown in Table 1.

Comparative Example 8 (C8) A hydroentangled one bound compound produced in Example 8 was tested for its properties. The results are shown in Table 1.

Table 1 Weight Base Layer Weight Base Total (gsm)% Opacity% Volume (min) Component (gsm)% Change% Change% Example 'Fi £? 2 Pre Pst, Change Pst, Total Pre Pst, Change Pst. Total Pre Pst, Change C2 22 15 - 68 33 -51% - 43.5 33.8 -22.3% - 0.46 0.71 56% C3 34 34 - 37 23 -38% - 65.1 55.4 -45.6% - 0.76 1.19 57% C4 22 15 22 59 48 -18% - 56.4 53.3 -5.5% - 0.69 1.55 126% Ex2 34 30 27 91 90 -1% 84 68.7 73.4 6.8% 69.7 1.5 0.38 0.56 47% Ex3 34 30 27 91 90 -1% - 60.8 61.2 0.7% - 0.56 0.76 36% C5 34 30 27 91 88 -3% - 70.0 68.4 -2.3% - 0.71 1.32 86% Ex4 34 15 27 76 75 -1% - 63.7 66.4 4.2% - 0.38 0.64 67% Ex5 34 15 27 76 75 -1% - 68.5 70.1 2.3% - 0.56 0.76 36% C6 34 15 27 76 73 -4% - 64.8 60.0 -7.4% - 0.71 1.70 139% Ex6 27 15 27 64 63 -2% - 57.4 60.1 4.7% - 0.56 0.84 50% Ex7 27 15 27 64 63 -2% - 61.6 61.1 -0.8% - 0.56 0.66 18% C7 27 15 27 64 61 -5% - 57.4 55.9 -2.6% - 0.56 2.34 254% Ex8 27 15 27 64 63 -2% - 64.3 63.2 -1.7% - 0.58 0.99 70% C8 27 15 27 64 61 -5% - 57.8 50.6 -12.5% - 0.64 2.24 252% Note: F. = first filament layer. P = cellulose layer F2 = second filamentous layer Pre = pre-wash Pstx = post-wash one cycle Pot, * poflt- washed five cycles The compounds of the above-mentioned examples all had a soft cloth-type texture, and when the samples were patterned, said samples exhibited cotton-like texture. The texture, visual and physical properties of the bound and unbound samples were clearly distinguishable after they were subjected to the washing process.

The decrease in the base step indicates the amount of pulp fibers lost during the wash cycle, and the decrease in opacity indicates that portions of the fibers forming the compound were rearranged or lost during the wash cycle while the increase in the Opacity indicates that the fibers of the composite were somewhat repositioned to form a composite having a denser or more uniform pulp fiber coverage. The increase in opacity may indicate that the compound increased its volume, for example, rose, while retaining its uniform fiber coverage. It is noted that an increase in volume measurement for a post-wash compound does not necessarily indicate an improved uniformity of the washed compound since the volume measurement can also be increased if the pulp fibers are stacked at different places within the composite.

The large decreases in the base weight for Comparative Examples 2-4 containing bound filamentary fabrics when compared to other comparative examples using unbonded filamentous fabrics, clearly demonstrate that the freedom of movement between the movements of the fabrics is very important for firmly fixing or entangling the pulp fibers and the filaments. In addition, the relatively low decrease of the basis weight and the opacity shown by Comparative Example 4, compared to Comparative Examples 2-3, illustrate that having two outer layers of a filamentous fabric, instead of an outer fabric layer, in Comparative Examples 2 and 3 significantly improve the stability of the hydroentangled compound.

The basis weight and opacity data for Examples 2-8 and Comparative Examples 5-8 show that the pattern-binding step of producing the present compound significantly improves the durability and washing of the hydroentangled compound. For example, the compound of Example 2 only lost about 1% by weight of the weight of the total compound after one wash cycle, while the unbound counterpart compound lost about 3% by weight during the first wash cycle. As indicated by the opacity data, the compound of Example 2 essentially retained its uniform fiber coverage and its cloth-like texture properties even after five wash cycles, but the unbound compound developed holes and formed fiber regions lumpy cellulose during the wash cycle. The durability and stability of the bound compounds was most pronounced when specimens of a lighter base weight compound were tested, for example, Examples 6-7 and Comparative Example 7 were washed.

Although the change in volume during the wash cycle is not a direct indicator of the durability of the compound, as discussed above, in general a smaller change in volume indicates that the fibers of the composite are more cohesively entangled and bonded. The volume changes between the bound and unbound compounds are dramatically different, as can be seen from the volume change data of Examples 2-8 and unbound counterpart compounds, Comparative Examples 5-8.

Ejeinplo 9 (Ex9) Example 9 and Comparative Examples 9-10, given below, were carried out to illustrate the importance of placing the cellulosic layer between the outer layers of the filamentous fabrics.

A hydroentangled composite bonded to a high weight basis pulp layer was prepared according to Example 6, except that the pulp sheet had a basis weight of 55 grams per square meter and the energy-impact value used was about 0.16 MJ-N / kg. It should be noted that for this example, the pulp layer was placed between the two filamentous layers, and then the compound was hydroentangled and bound. The bound compound was subjected to two complete cycles of the washing process. The physical properties of the compound are shown in Table 2.

Comparative Example 9 (C9) A hydroentangled compound was produced following the Example 9 except that the pulp layer was placed on top of two layers of filament fabric, making a composite two sides. The compound was hydroentangled by exposing the pulp layer to the jet stream, and then the composite was bonded according to Example 9 with its pulp layer exposed to the patterned bonding roller. The physical properties of the compound are shown in Table 2.

Comparative Example 10 (CIO) A hydroentangled composite was produced following Comparative Example 9, except that the filament fabric layer was exposed to the patterned bonding roller. The physical properties of the compound are shown in Table 2.

Table 2 Weight Layer Weight Base Total Opacity Base (gsm) (gsm)% E emplo 1 2 3 Pre Pst? Cambj Pre Pst Change Ex9 F26 P55 F26 107 104 -3% 76.3 77.6 2% C9 F26 F26 P55 107 94 -12% 75.9 68.7 -9% CIO P55 F26 F26 107 88 -18% 77.0 61.6 -20% Note: F .. = filamentous layer and the weight of the layer. P .. = cellulose layer and the weight of the layer. Pre = pre-wash. Pst2 = post-wash two cycles.

The changes in basis weight and opacity between Example 9 and Comparative Examples 9-10 clearly show that the placement of the cellulosic layer between the two outer layers of filamentous fabrics significantly improves the durability of the composite. After the wash cycle, the bound compound of Example 9 retained its cotton fabric type visual and textural properties, while unbound compounds developed a large number of holes and uneven fiber cover sections.

Example 10 (ExlO) Example 9 was repeated except that the filamentous fabric made of filaments joined by crimped monocomponent polypropylene yarn, the pulp layer had a basis weight of 33 grams per square meter and the energy-impact value used was around 0.35. MJ-N / kg. The polypropylene was NRD5-1258 from Shell Chemical, and the monocomponent filaments were produced using only an extruder and a monocomponent spin pack. Curls for the filaments were imparted by asymmetrically cooling the filaments as they exited the spin pack. The results are shown in Table 3.

Comparative Example 11 (Cll) Example 10 was repeated except that the filamentous fabric layers were prepared from crimped bicomponent short fibers, which had a length of 3.7 cm and about 2.5 crimps / cm and the energy-impact value used was around 0.20 MJ -N / kg. The short fiber is available from Hoechst Celanese Corporation, and it contains a polyester core and a copolyolefin sheath (Type 255). The short fibers were carded to form the fabric layers. The results are shown in Table 3.

Table 3 Weight Layer Weight Base Total Opacity Base (gsm) (gsm)%% Example Ei £ £ 2 Pre Pst7 Change Pre Pst .. Change ExlO 26 33 26 85 84 -1% 74.5 76.5 3% Cll 26 33 26 85 80 -6% 64.6 56.2 -13% Note: Fx = first filamentous layer. P = cellulose layer. F2 = second filament layer. Pre = pre-wash. Pst2 = post-wash two cycles.

Example 10 was carried out to demonstrate that the filamentous fabric of the present invention does not have to be produced from conjugated fibers and Comparative Example 11 was carried out to demonstrate the importance of using the continuous filaments.

The bound compound of Example 10 had cloth-type visual and textural properties, more particularly of cotton-type, and these desirable properties were not changed by the wash cycle as illustrated by the data mentioned above. In contrast, during the wash cycle, Comparative Example 11 lost a large portion of the cellulosic fibers, and the fibers of the compound rearranged to have uneven volume and holes.

As seen from the examples mentioned above, the post-bonded hydroentangled compound of the present invention has high dimensional stability and durability as well as highly desirable cloth-like texture properties, absorbency and breathability. Consequently, the bonded compound is an excellent material for various applications, especially for skin contact applications.

Claims (20)

R E I V I N D I C A C I O N S

1. A washable compound comprising: a) a first filamentary layer, said first layer comprises curled continuous filaments, b) a second filament layer, said second layer comprises crimped continuous filaments, and c) a cellulosic layer, said cellulosic layer comprises cellulosic fibers and is positioned between the first and second filamentous layers, wherein said compound is a hydroentangled compound that is patterned, and said pattern loses less than about 2% of its opacity, based on the initial opacity of said compound, when it is subjected to a washing cycle according to the process washing and drying of ASTM 2724-87.

2. The washable compound as claimed in clause 1, characterized in that said compound loses less than about 5% of its weight during said wash cycle.

3. The washable compound as claimed in clause 1, characterized in that said crimped filaments are selected from monocomponent filament and multicomponent conjugate filaments.

4. The washable compound as claimed in clause 1, characterized in that said crimped filaments are filaments joined by spinning.

5. The washable compound as claimed in clause 1, characterized in that said crimped filaments comprise at least one thermoplastic fiber-forming polymer selected from polyolefins, polyesters, polyamides, and copolymers and mixtures thereof.

6. The washable compound as claimed in clause 5, characterized in that said crimped filaments comprise at least one polyolefin.

7. The washable compound as claimed in clause 1, characterized in that said crimped filaments are conjugated spunbond filaments comprising polyethylene and polypropylene.

8. The washable compound as claimed in clause 1, characterized in that said cellulosic fibers are selected from southern pines, kraft pulp from soft northern wood, red cedar, spruce, eucalyptus, black spruce and mixtures thereof.

9. The washable compound as claimed in clause 1, characterized in that said compound is hydroentangled on both sides of the compound.

10. The washable compound as claimed in clause 1, characterized in that said compound is patterned with a bonding pattern having bound regions distributed in an essentially uniform manner and imparting a total bound area of between about 10% and 50%. % of the total surface area of said compound.

11. The washable compound as claimed in clause 10, characterized in that said compound is autogenously bonded with a standard.

12. The washable compound as claimed in clause 10, characterized in that said compound is adhesively bonded.

13. A durable hydroentangled compound which comprises two layers of filamentous fabric comprising crimped continuous filaments and a cellulosic layer comprising cellulosic fibers, said cellulosic layer being placed between said layers of filamentous fabric, wherein said compound is a hydroentangled compound that is patterned.

14. The durable compound as claimed in clause 13, characterized in that said compound loses less than about 2% of its opacity and less than about 5% of its weight, based on the initial opacity and weight of said compound, when it is subjected to a washing cycle according to the washing and drying process AST 2724-87.

15. The durable compound as claimed in clause 13, characterized in that said crimped continuous filaments are monocomponent filaments and multi-component conjugated filaments.

16. The durable compound as claimed in clause 13, characterized in that said crimped filaments are filaments joined by spinning and conjugates comprising polyethylene and polypropylene.

17. The durable compound as claimed in clause 13, characterized in that said compound is patterned with a bonding pattern having bound regions distributed essentially uniformly and imparting a total bound area of between about 10% and 50% of the total surface area of said compound.

18. A process to produce a durable compound, which comprises the steps of: a) providing a layered structure comprising a first layer of filamentous fabric of crimped filaments, a second layer of filamentous fabric of crimped filaments and a cellulosic layer placed between said first and second fabric layers, b) hydroentangling said structure in capable of forming a bonded laminate, and c) patterning said bonded laminate to form said compound, wherein said compound loses less than about 2% of its opacity, based on the initial opacity of said compound, when subjected to a washing cycle according to the washing and drying process AST 2724-87.

19. The process for producing a durable composite as claimed in clause 18, characterized in that said crimped filaments comprise a fiber-forming thermoplastic and said cellulosic layer comprises pulp fibers.

20. The process for producing a durable compound as claimed in clause 18, characterized in that said compound is patterned with a bonding pattern having substantially uniformly distributed bound regions and imparting a total bound area of between about 10. % and 50% of the total surface area of said compound. SUMMARY The present invention provides a washable and durable hydroentangled compound that is highly suitable for skin contact uses. The compound is a hydroentangled compound which is patterned. The composite contains two layers of filamentous fabric containing crimped continuous filaments and a cellulosic layer containing cellulosic fibers, and the cellulosic layer is placed between the layers of filamentous fabric. The composite fabric is washable as demonstrated by the fact that the compound loses less than about 2% of its opacity, based on the initial opacity of the compound, when it is subjected to a wash cycle according to the washing procedure and dried AST 2724-87. A process for producing the compound is further provided.