MXPA01008608A - Extrusion die - Google Patents

Abstract

An extrusion die for extruding a chemical functional additive for making a disposable paper product comprises a supply port and a distribution channel in fluid communication with the supply port. The distribution channel terminates with at least one discharge mouth having a passage cross-section therethrough. The discharge mouth comprises an entry orifice having an entry open area Ae, an exit orifice having an exit open area Ax, and a discharge distance defined between the entry orifice and the exit orifice. The exit open area Ax is greater than the entry open area Ae. This ensures that contaminants would pass through the discharge mouth, whereby plugging thereof is substantially avoided. Preferably, the passage cross-section of the discharge mouth continuously and gradually increases from the entry orifice to the exit orifice.

Description

EXTRUSION PRESS FIELD OF THE INVENTION The present invention relates, in general, to the processes and, therefore, to the extrusion equipment. More specifically, the present invention involves processes and apparatuses for the extrusion of chemical functional additives used in the manufacture of disposable articles such as paper towels, napkins, toilet paper, tissues, etc.

BACKGROUND OF THE INVENTION Extrusion presses for depositing an extrudable fluid on a substrate are known in the technical field. Extruders, generally known in the technical field, as hanger-type extruders are described, for example, in the following American patents: 4,043,739 issued August 23, 1997 to Appel and assigned to Kimberly-Clark Corporation; 4,372,739 issued on February 8, 1983 for Vetter et al. and assigned to Rom GmbH of Darmstadt, Germany; 5,234,330 issued August 10, 1993 for Billow et al. and assigned to Eastman Kodak Company; 5,494,429 issued on February 27, 1996 for ilson et al. and assigned to Extrusion Dies, Inc. Some other types of Pl336 extrusion apparatus, for example, in the following American patents: 5,607,726 issued in March 1997 for Flattery et al. and assigned to E. D. du Pont de Nemours and Company; 5,522,931 awarded Iwashita et al. on June 4, 1996 and assigned to Konica Corporation of Japan; 5,740,963 granted to Riney on April 21, 1998 and assigned to Nordson Corporation; 5,511,962 issued to Lippert and assigned to Extrusion Dies, Inc. One of the concerns related to extrusion presses in the prior art has been the obstruction in the discharge mouth of the extruder, for example, the outlet through which the fluid extrudable leaves the extrusion press. Extrusion presses are often used in environments where there is a lot of dust. In papermaking, for example, some sheets of paper tend to be particularly prone to release fibers from the surface. A powder that mainly comprises fibers for papermaking, can cause contamination to a chemical functional additive, for example, a topical fabric softener, which is deposited on the paper sheet in a routine manner. Other common contaminants can include degradation products of the extrudable fluid itself, which can occur particularly in the stagnation areas that lie around the walls of the extrusion press. The accumulation of these degradation products can form, over a period of time, scale and eventually these will separate from the walls of the extrusion press, thereby becoming a contaminant. More generally, the particles of soil, sand, refuse and grit tend to be entrained by the air in the vicinity of the extrusion operation area and are deposited within the supply of the extrudable fluid feeding the extrusion press. If the chemical functional softener, for example, is deposited within the substrate by extrusion, contaminants that have found a course within the functional additive that is being extruded could clog the exit of the discharge from the extrusion press. The cleaning process of the extrusion press is generally expensive, because it involves an interruption in the production line and / or a considerable effort. Cleaning can be even more complicated in extrusion presses designed to extrude very thin layers of extruded mixes and, consequently, comprise very small discharge nozzles (in the range of 0.0002-0.00450 inches) that require maintenance with tolerances of high precision. At present it has been found that the discharge mouths having a divergent "bell shape" in a cross section, can beneficially mitigate, and even more, eliminate the problem of obstruction in the discharge mouth. In accordance with the above, the present invention advantageously provides a novel extrusion apparatus comprising a discharge mouth with an open entrance area and an open exit area that is larger than the entry orifice. The present invention also provides the advantage of an extrusion process that substantially eliminates clogging in the discharge mouth of the extrusion apparatus. Other objects, features and advantages of the present invention will be apparent from the following description in conjunction with the accompanying drawings, although there may be variations and permutations without departing from the spirit and scope of the disclosure.

SUMMARY OF THE INVENTION The present invention provides an extrusion press and a process for extruding an extrudable fluid onto the substrate of a membrane. A preferred extrudable fluid comprises a chemical functional additive commonly used in the manufacture of disposable articles such as paper towels, napkins, toilet paper, face towels, sanitary napkins, diapers, etc. The extrudable fluid may be selected from a group consisting of softeners, emulsions, emollients, lotions, topical medicaments, soaps, antimicrobial and antibacterial agents, humectants, coatings, inks, dyes and binders. A preferred membrane substrate comprises a fibrous membrane, for example, a sheet of paper. It should be understood, however, that the extrusion press and the process of the present invention can be used beneficially with other types of extrudable fluids and with other types of substrates. The extrusion press of the present invention comprises a supply port and a distribution channel in fluid communication with the supply port. The distribution channel ends with at least one discharge mouth having a transverse entry in the middle. The discharge mouth comprises an inlet orifice, an outlet orifice and a discharge distance between the two orifices. The entrance hole has an open entrance area Ae and the exit orifice has an open exit area Ax. According to the present invention, the open exit area Ax is larger than the open entry area Ae. The ratio Ax / Ae is preferably between about 1.1 and about 10, more preferably between about 1.2 and about 5 and preferably superlative between about 1.5 and about 2. In a preferred part of the extrusion press, the transverse entrance of the mouth of discharge increases continuously and gradually from the open area of entrance Ae to the open area of exit Ax. The discharge mouth is bell-shaped, preferably gradual and continuous, in at least one cross section. More preferably, the discharge mouth is bell-shaped in at least two mutually perpendicular transverse cuts and, preferably superlatively, the discharge mouth has a gradual and continuous bell shape in any of its cross sections, for example, approximately 360 °. The discharge mouth may have various configurations, including in an unrestricted manner: an elongated slot, a substantially circular opening and any combination thereof. The discharge distance of the discharge mouth is preferably from about 0.0075 to about 0.1 inches and more preferably from about 0.010 to about 0.050 inches. The open outlet area Ax of the discharge mouth is preferably from about 0.10 to about 2.5 square inches and more preferably from about 0.2 to about 1.0 square inches. In the preferred part, the extrusion apparatus further has a lip with a knife edge. The discharge mouth (s) is related to the lip, so that during the extrusion process the substrate of the membrane can be brought into contact with the blade edge of the lip. In a particularly preferred part of the extrusion press comprising a plurality of circular discharge nozzles, the blade edge of the lip extends between the discharge orifices of the discharge ports. Said discharge nozzles can be formed by perforating the bell-shaped holes in the press through the blade edge of the lip. The process of the present invention comprises the following steps: supplying an extrudable fluid; provide a substrate for the membrane; providing an extrusion press of the present invention described herein above; extruding the extrudable fluid through the discharge mouth of the extrusion press, while the substrate of the membrane moves continuously relative to the extrusion press and contacting the substrate of the membrane with the extruded fluid. During the process, at least some of the relatively large contaminants contained in the extrudable fluid, for example, those contaminants having at least one dimension that is greater than at least one dimension of the open area of entry, are excluded from the entrance to the discharge mouth. At the same time, at least some of the relatively small contaminants, for example, contaminants having at least one dimension that is less than at least one dimension of the open area of entry, pass through the discharge mouth without be clogged in there It is believed that during the process described using an extrusion press of the present invention, the obstruction in the discharge mouth is substantially reduced or even avoided. Some of the contaminants that are excluded from the inlet to the discharge mouth may still be in the vicinity of the inlet port and, consequently, restrict the flow of the extrudable fluid through the discharge port. To avoid this problem, back pressure, for a short period of time, can be applied to the extrudable fluid within the distribution channel.

BRIEF DESCRIPTION OF THE DRAWINGS OR FIGURES Figure 1 is a schematic perspective view of an illustrative process of the present invention showing an embodiment of an extrusion apparatus of the present invention in conjunction with a P1336 sheet of paper in movement. Figure 2 is a schematic partial cross-sectional view of the extrusion press of the present invention showing the discharge mouth of the press. Figure 3 is a schematic and more detailed view of the discharge mouth shown in Figure 2. Figure 3A is a schematic cross-sectional view of the discharge mouth with a discrete bell shape. Figure 4A is a schematic partial cross-sectional view of the extrusion apparatus, taken along lines 4-4 of Figure 3 showing a modality of the discharge mouth. Figure 4B is a schematic partial cross-sectional view similar to that shown in Figure 4A, showing another embodiment of the discharge mouth. Figure 5 is a schematic partial view taken in the direction of an arrow 5 of Figure 4A showing a modality of the discharge mouth comprising a circular opening. Figure 6 is a partial schematic view similar to that shown in Figure 5, showing another embodiment of the discharge mouth comprising an elongated slot. Figure 7 is a partial schematic view similar to that shown in Figure 5, showing yet another Pl336 modality of the discharge mouth comprising an elongated slot. Figure 8 is a schematic partial cross-sectional view of the extrusion press of the present invention having a discharge mouth comprising a lip with a knife edge. Figure 9 is a schematic partial cross-sectional view of the extrusion apparatus, carried along lines 9-9 of Figure 8. Figure 10 is a schematic partial view taken in the direction of an arrow 10 of Figure 9 showing a modality of the discharge mouth comprising a semicircular opening. Figure 11 is a schematic partial view of the extrusion apparatus shown in conjunction with a substrate.

DETAILED DESCRIPTION OF THE INVENTION An extrusion press 10 of the present invention comprises a body having a supply port 11 and a distribution channel 15 in fluid communication with the supply port 11, as shown schematically in the FIGURES 1 and 2. As used herein, the term "supply port" 11 refers to an entry in the body of Pl336 the extrusion press 10, through which an extrudable fluid is delivered, preferably under pressure, into the distribution channel 15. As used herein, the term "extrudable fluid" refers to any fluid, including liquid materials , as well as gaseous, which has the ability to be extruded using the apparatus 10 and the process of the present invention. Examples of extrudable fluid 80 include, unrestrictedly: water; alcohol; functional additives such as softeners (siloxanes, oils, quaternary ammonium, waxes and others), emulsions, emollients, lotions, topical medicaments, soaps, various antimicrobial and antibacterial agents and humectants (for example glycol); loading materials such as, for example, clay loading; a variety of resins; coatings for example, clay and latex and various opacifiers; inks and dyes; binders; reactive and non-reactive vapors, for example, oxygen and nitrogen. In Figure 1, a conveyor 70 comprising a substrate of the membrane 50 is shown moving in the direction of the MD machine. As used herein, the term "conveyor" is generic and refers to any medium over which the extruded fluid can be deposited according to the process of the present invention. Two parts of the preferred conveyor 70 are a roller Transfer pl336 (not shown) and a membrane substrate 50. Those who master the technical field will appreciate that a transfer roller, for example, a roller for moving a printing process can be used to carry out an indirect application of the fluid extruded to the substrate. The reference was also made for the "machine direction" designated in several drawings as the directional arrow "MD" and for "direction transverse to the machine" designated as a directional arrow "CD". As used herein, the term "machine direction" indicates a direction parallel to the flow of the substrate 50 through the equipment. The term "cross machine direction" indicates a direction perpendicular to the machine direction and is located in the general plane of the substrate 70. In some embodiments of the process according to the present invention, the extrusion apparatus 10 can be placed, in relation to the substrate 70, in such a way that the width of the outlet is parallel to the transverse direction of the CD machine, as shown schematically in FIGURES 2 and 4. It should be noted, however, that they can be made and that, moreover, those in which the exit is arranged in such a way that the widthwise direction is not parallel to the direction transverse to the CD machine, may be desired, For example, the direction of the exit with width W and the transverse direction of the CD machine form an acute angle in the middle (not shown). In a preferred embodiment, the extrusion apparatus 10 comprises a one-piece body. However, the extrusion press must be formed by two halves that match 10a and 10b (Figure 1), a general design that will be easily recognizable by those who dominate the technical field. Each of the halves 10a and 10b has a cavity in such a way that when the halves 10a and 10b are sealed together, their cavities form the distribution channel 15. As used herein, the term "distribution channel" 15 refers to three-dimensional or recessed spaces, within the press 10, structured and designed to receive the extrudable fluid. As used herein, the term "lip" 20 (FIGURES 1 and 2) refers to the farthest exit surface of the extrusion press 10, relative to the general direction of the extrudable fluid flow at the exit point. of the press 10. In some embodiments, the lip 20 can be brought into contact with the substrate 50 (Figure 1), on which the extrudable fluid is deposited. In the mode of the press 10 comprising two halves 10a and 10b, the lip 20 can be formed of at least one advance lip (belonging to one of the two halves 10a, 10b) and P1336 of a drag lip (belonging to one of the two halves 10a, 10b). In a preferred embodiment of the press 10 according to the present invention, the lip 20 comprises a "blade edge", for example a relatively sharp surface formed by two surfaces connected at the angle a, as best shown in Figure 8. The distribution channel 15 ends with at least one discharge mouth 21 having a transverse entry for the extrudable fluid to pass therethrough. As used herein, the term "discharge mouth" 21 refers to an opening or hollow in the lip 20, through which inlet conduit the extrudable fluid leaves the press 10 and, as a consequence, thereby forms an extruded fluid. As best shown in FIGS. 3, 4A and 4B, the discharge mouth 21 is comprised and extended between an inlet 21e and an outlet 21x. The discharge mouth has a discharge distance H defined between the inlet 21e and the outlet 21x. The discharge distance H is within the range of preferably 0.005 - 0.250 inches, more preferably 0.0075 - 0.100 inches and preferably superlative 0.010 - 0.050 inches. It should be carefully noted that the angle formed between the inner surfaces of the halves 10a and 10b may or may not be equal to the angle a (Figure 8). Preferably, the angle a is greater than the angle α. In this way, the discharge distance H can be minimized. The transverse inlet of the discharge mouth 21 has a variable open area A which increases from the inlet 21x to the outlet 21x, as will be explained in more detail below. The inlet 2le has an open entrance area Ae and the exit orifice 21x has an open exit area Ax. As used herein, the term "open entrance area" Ae is an area through which the extrudable fluid enters the discharge mouth 21; the term "open exit area" Ax is an area through which the extrudable fluid exits from the discharge mouth 21 - and hence from the extrusion press 10. Expressed differently, the open entry area Ae and the open exit area Ax refers to the areas through which the extrudable fluid passes consecutively as it enters and exits, respectively, from the discharge mouth 21. The open areas Ae and Ax are typically measured in square units in a plane defined by the perimeter of a given open area - either a plane defined by the perimeter of the inlet 21e, or a plane defined by the perimeter of the outlet orifice 21x, respectively. Reference was also made earlier P1336 to the generic term "open area" designated by "A" (Figure 4A). The open area A refers to any area within the discharge mouth 21, where the area is generally orthogonal to the flow of the extrudable fluid through the discharge mouth 21 and defined by its perimeter at any point between the open entry area Ae and the open exit area Ax. Those who master the technical field will appreciate that within the discharge distance H of the discharge mouth 21, for example, between the open entrance area Ae and the open exit area Ax, there will be an unlimited number of open transverse areas "A " In some embodiments, both the inlet 21e and outlet 21x holes are arranged in planes that are generally orthogonal to the flow of the extrudable fluid (FIGURES 3,4A and 4B). In the case, however, that at least one of the inlet holes 21e or a portion thereof and the outlet orifice 21x or a portion thereof are arranged in planes that are not orthogonal to the flow of the extrudable fluid (FIGURES 8- 10), the open entrance area Ae and / or the open exit area Ax will also not be orthogonal to the flow of the extrudable fluid. In FIGS. 8-10, the extrusion press 10 has a lip with blade edge 20 / formed between two surfaces at an angle a and a plurality of discharge mouths 21 having a P1336 circular shape. As those who dominate the technical field would appreciate, the circular shape of the discharge mouth 21 appears as a semi-elliptical figure in each of the planes of the surfaces that form the angle a. In FIGS. 8-10, the open input area Ae comprises a first input portion Ael and a second input portion Ae2; the output open area Ax comprises a first output portion Axi and a second output portion Ax2. It should be carefully noted that in FIGS. 8-10, the first input portion Ael is not parallel to the second input portion Ae2 and that the first output portion Axi is not parallel to the second output portion Ax2. Expressed differently, each of the open areas of input Ae and output Ax is in two planes (Figure 9), both of which may not be orthogonal to the flow of the extrudable fluid through the discharge mouth. It should also be noted that the first input portion Ael must not necessarily be parallel to the first output portion Axi and the second input portion Ae2 must not necessarily be parallel to the second output portion Ax2. In the embodiments shown primarily in FIGS. 8-10, the discharge distance H can be calculated as an arithmetic average of a first distance and a second distance, the first distance being a distance between P1336 a center of mass of the first input portion Ael and a center of mass of the first output portion Axi and a second distance being a distance between a center of mass of the second input portion Ae2 and a center of mass of the second output portion Ax2. Assuming that a longitudinal axis (not shown) of the discharge mouth 21 divides the angle a in the same way, an open total exit area Ax / 2 of the only semi-elliptical portion (either Axi or Ax2) of the exit orifice 21x is equal to Ax = p (x4) 2 / 4cos [90o- (a / 2) °], where x4 is the diameter of the exit hole 21x. Similarly, the total open area Ae / 2 of the discharge mouth 21 can be calculated. It should be taken into account, however, that the angle formed between the surfaces in which the first input portion Ael and the second portion of input Ae2 are formed, can be different from angle a. Without taking into account its specific embodiment, the discharge mouth 21 of the extrusion press 10 of the present invention has certain characteristics. According to the present invention, the open exit area Ax of the discharge mouth 21 is larger than the open entry area Ae. This ensures that at least some of the relatively large contaminants 30a (Figure 4A) contained in the extrudable fluid and having at least one dimension that is greater than at least one P1336 dimension e2 of the open area of entrance 21e will be excluded from the entrance to the discharge mouth. At the same time, at least some of the relatively small contaminants 30b (Figure 4A) contained in the extrudable fluid and having at least one dimension that is less than at least one dimension e2 of the open input area 21e will pass through. from the discharge mouth 21 without being obstructed in there. In other words, if a particular contaminant is small enough to enter the discharge mouth 21 through the open entry area 21e it will undoubtedly pass through the open exit area 21x which is greater than the open entry area 2le. In this way, obstruction of the mouth 21 can be substantially avoided. Preferably the ratio Ax / Ae is between 1 and 10, more preferably the ratio Ae / Ax is between approximately 1.2 and 5 and preferably superlative the ratio Ae / Ax is between approximately 1.5 and 2. Preferably, the transverse input from the discharge mouth 21 and, consequently, the open area A, are continuously and gradually increased from the open entrance area Ae to the open exit area Ax. As has been employed here, by means of a "continuous and gradual" increase of the open area A means that any Pl336 increase in a distance from the open entrance area Ae to the open exit area Ax corresponds to an increase in the cross-sectional area A of the discharge outlet 21. At a given outlet 21, the transverse entry has an open area variable A which is minimal when the open area A comprises the open area of entry Ae and is maximum when the open area A comprises the open exit area Ax. Preferably, the Ax / H ratio is between about 0.005 to about 10, more preferably, the Ax / H ratio is between about 0.10 to about 5 and preferably superlative, the Ax / H ratio is between about 0.10 to about 1.5. In FIGURES 3-10 various embodiments of the discharge mouth 21 are shown, according to the present invention. Preferably, the discharge mouth 21 divergently has a bell shape in at least one cross section, as shown in FIGURES 3 and 4B, seen in combination. In the cross section shown in Figure 3, the dimension of the inlet hole 21e is smaller than the dimension xl of the outlet orifice 21x, while in the cross section shown in Figure 4B (which is orthogonal to the cross section of the Figure 3), the dimension e3 is equal to the dimension x3. More preferably, the discharge mouth 21 is bell-shaped P1336 in at least two mutually perpendicular cross sections, as shown in FIGS. 3 and 4A, seen in combination. In Figure 4A, an e2 dimension of the inlet 21e is less than a dimension x2 of the outlet 21x. With superlative preference, the discharge mouth 21 has the shape of a bell in each of its transversal cuts, as best shown in FIGS. 5 and 7. While another mode is possible in which the discharge mouth 21 has a discreet shape of bell, or discontinuously, as shown in Figure 3A, it is highly preferable that the discharge mouth 21 has a bell-shaped form, as best shown in FIGURES 3 and 4A. As used herein, the requirement that the discharge mouth 21 has "gradually bell-shaped" refers to an uninterrupted continuity of an increase in the open transverse area A of the discharge mouth 21 from the open entrance area Ae to the open exit area Ax, where any increase in a distance from the open entry area Ae to the open exit area Ax corresponds to an increase in the cross-sectional area A of the discharge mouth 21. It should be understood that while in various embodiments of the walls 22 of the discharge mouth 21 are shown as straight lines (FIGURES 3 and 4A), modalities are possible in which the walls 22 P1336 comprise curved lines (not shown). Depending on the requirements of a particular extrusion process, the discharge mouth 21 could comprise a variety of shapes and configurations. FIGURES 5 and 7, for example, show a plurality of discharge nozzles 21 distributed along the lip 20 of the press 10. In Figure 5, the discharge mouth 21 comprises a circular opening having an orifice diameter e2. of entrance and a diameter x2 of the exit orifice. Figure 6 shows the discharge mouth 21 comprising an elongated slot extending along the width of the press 10, while Figure 7 shows a plurality of discharge nozzles 21, each comprising an elongated slot. Other variations and permutations of the shapes of the discharge mouth 21, including rectangular shapes and irregular configurations (not shown) of the open areas, are included in the scope of the present invention. Those who dominate the technical field will know how to calculate the open area of entry Ae and the open area of exit Ax, depending on their respective forms. At least one method of calculating the open area with a non-circular (or irregular) shape involves an equivalent diameter. The term "equivalent diameter" is used here to Pl336 define the open transverse area that has a non-circular shape, in relation to the transversal area as it has a circular geometric shape. An open area of any geometric shape can be described according to the following formula: A = l / 4pD2, where "A" is an open area of any geometric shape, p = 3.14159 and "D" is the equivalent diameter. For example, an open area A with a rectangular shape can be expressed as a circle of an open area equivalent to "a" having a diameter "d". Then, the diameter d can be calculated from the formula: a = l / 4 pd2, where a is the known open area of the rectangle. In the previous example, the diameter d is the equivalent diameter D of this rectangle. Of course, the equivalent diameter of a circle is the actual diameter of the circle. Thus, in Figure 5, the open entrance area Ae of the discharge mouth 21 is equal to Ae = l / 4p (e2) 2 where e2 is the diameter of the open entrance area Ae; the open outlet area Ax of the discharge mouth 21 is equal to Ax = l / 4p (x2) 2 where x2 is the diameter of the exit open area Ax. In FIGS. 8-10 an exemplary embodiment of the extrusion press 10 of the present invention having a lip 20 comprising "a knife edge" is shown. The lip with blade edge 20 is characterized by a relatively sharp edge 23 formed P1336 for two angled surfaces. During the extrusion process, the edge 23 preferably (but not necessarily) is brought into contact with the surface of the membrane 50. The preferred edge of the blade edge 20 is especially prepared for applications where the edge of the blade 23 can provide beneficially. , attenuation of the extruded fluid, causing the substrate 50 to pass in the direction substantially parallel to the surface of the half 10a and in contact with it or with the surface of the half 10b, or both, when the extruded fluid is being extruded. deposited on the substrate. Figure 11 shows a preferred embodiment of the extrusion apparatus 10 having a lip with blade edge 20 which is in contact with the substrate 50 moving in the direction of the MD machine. The press 10 has a plurality of circular mouths 21 spaced consecutively along the lip 20. Each mouth 21 has an open entrance area Ae and an open exit area Ax, according to the present invention. In Figure 11, the extrudable fluid is deposited on the substrate 50 at an acute angle, relative to the surface of the substrate 50. In other words, the press 10 and the substrate 50 are disposed, with respect to each, of such so that an angle ß is formed between the general direction of the movement of the extrudable fluid through the Pl336 discharge mouth 21 and the general plane of the substrate 50. This embodiment of the process, especially coupled with the semicircular shape of the discharge mouth 21, is believed to be especially beneficial because it advantageously provides a gradual introduction of the extrudable fluid on the substrate 50 or on any other conveyor, such as, for exa, a printing roller. Typically, in a continuous process, the speed of the substrate 50 is within the range of about 1000 - 5000 feet per minute, while an extruded fluid velocity is within the range of about 100-500 feet per minute. In some cases, this differential in speed could cause a longitudinal discontinuity in the extruded fluid that is being deposited on the substrate, due to a sudden acceleration of the extruded fluid when it comes into contact with the substrate. Without wishing to be bound by theory, applicants believe that the semicircular shape of the discharge mouth 21 causes the fluid extruded gradually (relative to the direction transverse to the CD machine) to come in contact with the substrate 50. The first Step of the process of the present invention comprises the provision of a conveyor 50 having a width. A wide variety of materials P13¡36 can be used as a conveyor 50. Exas include, but are not limited to: paper, fabrics, plastic including films, metal, woven and nonwoven materials. The conveyor 50 may comprise the substrate of the membrane or alternatively a printing roller (not shown). Structured papers as well as unstructured papers can be used as conveyors. Several exas of structured papers can be found in the following commonly assigned American patents: 4,529,480 issued July 16, 1985 to Trokhan; 4,637,859 issued on January 20, 1987 to Trokhan; 5,364,504 issued November 15, 1994 to Smurkoski, et al .; 5,529,664 issued June 25, 1996 to Trokhan, et al. and 5,679,222 issued October 21, 1997 to Rasch, et al. Other exas of papers that can be used as a conveyor 50 are described in the following American patents: 3,301,746 issued January 31, 1967 to Sanford, et al .; 3,974,025 granted on August 10, 1976 to Ayers; 4,191,609 granted on March 4, 1980 to Trokhan and 5,366,785 granted on November 22, 1994 to Sawdai. Monolayer membranes, thus multilayer corao, can be used as a substrate 50 in the present invention. The first step of the process of the present invention comprises the supply of a substrate for the membrane.

P1336 The next step comprises the supply of an extrusion press 10 according to the present invention and which was described in sufficient detail above. The next step comprises the supply of a chemical functional additive having the ability to be extruded with the extrusion press 10. The functional additive is preferably selected from the group consisting of softeners, emulsions, emollients, lotions, topical medicaments, soaps, antimicrobial agents and antibacterials, humectants, coatings, inks and dyes and binders, the functional additive being extrudable with the extrusion press. The next step comprises the extrusion of the functional additive with the extrusion press 10. As discussed in the present invention, during extrusion, at least some of the relatively large contaminants contained in the functional additive and having at least one dimension that is greater than at least one dimension of the open area of entry are excluded from the entrance to the discharge mouth, while at least some of the relatively small contaminants contained in the functional additive and having at least one dimension which is less than at least one dimension of the open area of entry, pass through the discharge mouth without being obstructed therein, thereby P1336 the obstruction of the discharge mouth is substantially avoided. The next step comprises contacting the substrate 50 of the membrane with the functional additive, and in this way, depositing the functional additive on the substrate of the membrane.

P1336

Claims (9)

1. CLAIMS: 1. An extrusion press (10) for extruding a chemical functional additive for the production of disposable paper products, the extrusion press (10) comprises a supply port (11), at least one lip (20) with termination on a knife edge (23) and a distribution channel (15) in fluid communication with the supply port (11); the distribution channel (15) ends in a plurality of discharge nozzles (21), each of the discharge nozzles (21) has a transverse inlet, each of the discharge nozzles (21) comprises an inlet orifice (21e), outlet hole (21x) and a discharge distance (H) defined therein in the middle; the inlet orifice (21e) has an open entrance area Ae and the outlet orifice (21x) has an open exit area Ax; the extrusion press (10) is characterized in that the discharge nozzles (21) are spaced consecutively along and separated from one another by a knife edge (23) of at least one lip (20) and the open area output Ax is greater than the open input area Ae.
2. 2. The extrusion press according to claim 1, wherein the transverse entry of the discharge mouth increases continuously and gradually from the open entrance area Ae to the open area of P1336 outlet Ax, preferably the bell-shaped discharge nozzle in at least one cross section and more preferably the discharge nozzle is bell-shaped in at least two mutually perpendicular cross sections.
3. The extrusion press according to claim 2, wherein the Ax / Ae ratio is between about 1.1 and about 10, preferably between 1.2 and 5 and more preferably between 1.5 and 2.
4. 4. The extrusion press according to claim 2 , wherein the discharge mouth comprises a substantially circular opening.
5. The extrusion press according to claim 4, wherein the discharge distance of the discharge mouth is from about 0.005 to about 0.250 inches, preferably from about 0.0075 to about 0.100 inches and more preferably from about 0.010 to about 0.050 inches.
6. The extrusion press according to claim 2, wherein the ratio Ax / H is from about 0.005 to about 10, preferably from about 0.010 to about 5 and more preferably from about 0.1 to about 1.5.
7. 7. The extrusion press according to P1336 claim 1, further comprising a lip with blade edge associated with at least one discharge mouth.
8. 8. A process for extruding a chemical functional additive used in the manufacture of disposable paper products, the process comprising the steps of: (a) supplying a chemical functional additive; (b) supplying an extrusion press (10) comprising a supply port (11), at least one lip (20) terminating in a knife edge (23) and a distribution channel (15) in fluid communication with the supply port (11); the distribution channel (15) with termination in at least one discharge nozzle (21) comprises an inlet orifice (21e), an outlet orifice (21x) and a discharge distance (H) defined therein in the middle; the entrance hole (21e) has an open entrance area (Ae) and the exit orifice (21x) has an open exit area (Ax); (c) extruding the functional additive through the plurality of discharge nozzles (21) of the extrusion press (10); the process is characterized in that in the step of supplying an extrusion press (10) the discharge ports (21) of the extrusion press are consecutively spaced apart and are separated from one another by the knife edge (23) of for the P1336 minus one lip (20) and the open exit area (Ax) of each of the discharge nozzles (21) is greater than the open entry area (Ae), whereby at least some of the relatively large contaminants contained in the functional additive and having at least one dimension that is greater than at least one dimension of the open area of entry (Ae) are excluded from the input to the discharge mouth (21), while at least some of the relatively small contaminants contained in the functional additive and having at least one dimension that is less than at least one dimension of the open input area (Ae) they pass through the discharge mouth (21) without obstructing it, thereby substantially obstructing the discharge mouth (21). The process according to claim 1, further comprising a step of periodically applying a back pressure to the functional additive contained in the distribution channel of the extrusion press and, consequently, displacing the relatively large contaminants which are located in the vicinity of the entry hole of the discharge mouth.