MXPA99008656A - Dual-zoned absorbent webs - Google Patents

Abstract

A dual-zoned, three-dimensional, resilient absorbent web is disclosed which is suitable as body-side liner for absorbent articles such as feminine pads, diapers and the like. When used as a liner in absorbent articles, the dual-zoned web combines the advantages of apertured films and soft, nonwoven cover layers in one structure while still being inherently hydrophilic. The liner comprises a web of wet-resilient, hydrophilic basesheet having a three-dimensional topography comprising elevated regions onto which hydrophobic matter is deposited or printed and a plurality of spaced apart depressed regions. In a preferred embodiment, the hydrophobic matter applied to the elevated regions of the basesheet comprises hydrophobic fibers in a contiguous nonwoven web which has been apertured or provided with slits or other openings, such that the apertures or openings overlay a portion of the depressed regions. The elevated hydrophobic regions enhance dry feel and promote fluid flow toward the lower hydrophilic regions, which comprise the exposed depressed regions of the basesheet. The basesheet is preferably in liquid communication with underlying absorbent material, most preferably a stabilized airlaid cellulosic material or compressed stabilized fluff such that the absorbent material can wick fluid out of the basesheet by capillary action. When soft, hydrophobic fibers are deposited on the elevated regions, the liner also has a soft, cloth-like feel in addition to a dry feel in use.

Description

ABSORBING FABRICS ZONED IN DUAL SHAPE Background of the Invention Absorbent articles are typically used in contact with the skin. Some absorbent articles such as disposable diapers, women's pads, panty liners, incontinence pads and the like are kept in contact with the skin to absorb liquids or exudates from the body, while other absorbent materials such as the Paper towels, hand towels and cleaning cloths can be held in the hands to absorb liquids on the skin or other surfaces. In virtually every case, it is desired that the article or absorbent material keep the liquids out of the skin to provide a dry and clean feeling and to reduce the skin health problems that arise from excessive hydration or contact with the materials. harmful chemicals or biologicals in the liquid that is being absorbed.

Although paper cleaners and towels are often composed of a homogeneous material, such as a fully cellulosic fabric, absorbent articles that are intended to absorb body fluids typically have at least three layers of different materials. Next to the user's skin is a layer of top sheet, sometimes referred to here as a liner, a side-to-body liner or a cover sheet. Beneath the top sheet is the absorbent core which is designed to retain the liquid, and below the absorbent core is a lower sheet impervious to the fluid which prevents runoff and maintains the integrity of the product. The top sheet should be soft and should have a high liquid permeability to allow body fluid such as urine, menstrual fluids, or bowel movement to be absorbed and transported out of the skin to reach the central absorbent core . Ideally, the top sheet provides a "dry feeling" or "dry touch" by preventing the liquid from flowing back to the skin. It is also desirable that the upper sheets have a high wet elasticity to maintain their volume and shape when they are wetted.

The upper sheets or traditional hydrophilic cover materials in contact with the skin can effectively serve to transport body fluids into the absorbent core, but these cause a moist sensation against the user's skin and can adversely affect the health of the user. skin. In addition, these can transmit the liquid in the full layer, allowing the liquid to approach the edges of the absorbent article and possibly drain or spill.

To achieve the goal of dryness and dry feeling in the upper sheets of absorbent articles, many manufacturers have turned to non-woven fabrics made of hydrophobic fibers for the upper contact sheet with the body. Even though the use of hydrophobic non-woven fabrics may have resulted in an improved dry feel, the hydrophobic material impairs transmission in the absorbent core, offers little absorbent capacity and reduces liquid permeability. In addition, the poor absorbency of most hydrophobic materials causes any liquid held there to be easily squeezed outward by the movement of the user's body.

Others have sought to improve poor transmission and absorbent properties of hydrophobic materials by applying a surfactant comprising surfactant on the surface of hydrophobic fibers. This approach may offer some benefits when the article is first moistened, but surfactants tend to be washed out, resulting in poorer performance with additional wetting.

In the case of absorbent pads for the care of women, two different approaches involving hydrophobic top sheets or covers are common. One approach is to use a non woven hydrophobic material from type of cloth and soft, which increases comfort but has the disadvantage of a poor menstrual fluid intake. Another approach is the use of a perforated plastic film of hydrophobic polymer or other materials. The hydrophobic cover material repels many body fluids, while the openings allow the transmission of the cover to the absorbent material below.

In theory, the hydrophobic perforated material should allow the wearer's skin to remain relatively dry while allowing transmission in the z-direction (normal to the plane of the cover) inside the underlying absorbent core. In practice, hydrophobic perforated films have a number of problems. Perforated films have the disadvantage of not liking some users for their plastic sensation and for their poor absorbency. Its hydrophobic nature resists transport through the material, possibly delaying transmission in the absorbent core. Similarly, liquid pockets or ponds can be formed between the film and the user's skin. In the absence of hydraulic pressure or physical compression, menstrual fluids in particular can stagnate on the hydrophobic surface and not penetrate into the perforations, especially if there is a significant interfacial separation between the cover and the underlying absorbent material.

There is therefore a need for an improved topsheet material which provides the clean feel that is said to be characteristic of hydrophobic top sheet materials, while a transport is provided in the z-direction (in the direction of depth) Rapid liquid flow through the upper sheet into the underlying absorbent core, a characteristic more typical of hydrophilic materials. Preferably, these absorbent top sheets also have a wet elasticity and absorbency properties which persist during multiple insults of urine or other liquids.

Synthesis of the Invention The present invention relates to elastic materials and compounds that offer once mutually exclusive benefits of high absorbency and dry and clean feel when used as skin contact layers that absorb body fluids or other liquids.

In the co-pending United States of America application, series number 08 / 614,420, "Wet Elastic Fabrics and Disposable Articles Made With The Same" by FJ Chen et al., Incorporated herein by reference, a novel wet laid tissue is taught. which has unusually high volume, wet elasticity, flat permeability and absorbency. The unusual properties of this material are achieved through a combination of high performance fibers, wet strength additives, and non-compressive drying of a three-dimensional molded structure. The three-dimensional structure of this material does not fold easily when it is wetted and therefore reduces the contact area with the skin when wetted, contributing to a relatively dry feeling. It has been found that the inherently hydrophilic material of this prior invention and related materials can be made essentially more useful in personal care articles by the selective addition of the hydrophobic material which can impart an increased dry feel and, in some embodiments, a Improved softness. With the hydrophobic material deposited on the uppermost body contact regions of the three-dimensional hydrophilic tissue, the higher body contact regions are made essentially hydrophobic to increase the feeling of a clean, dry feel, while a plurality of hydrophilic regions in said tissue remain accessible to body fluids, allowing liquids to be transmitted out of the body and into an absorbing medium. Therefore, the dry feel and the high absorbency are achieved in a single unitary layer or in a unique composite structure which can be a laminate of hydrophobic and hydrophilic materials. The hydrophobic material is integrally attached or held to the base sheet. The articles improved disposable absorbers comprising such materials include women's pads and panty liners, incontinence products such as diapers and liners, bed pads, disposable diapers, disposable training pants, disposable menstrual pants, chicken pads, bands or pads for disposable sweat, breast pads, shoe odor absorbing pads, towels, moistened cleansers, cleansers, medical pads, sterile wound dressings and pads, disposable garments, helmet linings or other protective or athletic equipment, pads for use in the waxing of automobiles and other surfaces, and the like. A simple example of an absorbent article containing a topsheet, an absorbent core and a bottom sheet is illustrated in U.S. Patent No. 3,809,089 issued May 7, 1974 to Hedstrom et al. Incorporated here by reference.

It has generally been found that the addition of the hydrophobic agents or materials on the relatively high portions of a surface of a three-dimensional wet elastic fibrous fabric, said fabric predominantly comprising intrinsically hydrophilic fibers, can improve the suitability of such fabrics for use in absorbent articles. by reducing the amount of fluid that can remain in contact with the skin or flow back to the skin during use as a absorbent article, therefore resulting in an improved dry feeling. Certain hydrophobic materials, such as fine synthetic fibers, provide a soft, pleasant, spongy and dry feeling, while others such as hydrophobic resins, gels, emulsions, waxes or liquids may increase the smoothness or apparent lubricity of the surface and improve the touch properties.

Suitable base sheets can be prepared from aqueous fiber solutions for making paper with known papermaking techniques. The fibers can be derived from wood or other sources of cellulose and preferably contain a part of high performance or other wet elastic pulp fibers and an effective amount of moisture resistance agents. The base sheets can be textured by continuous drying on a three-dimensional fabric or other means known in the art and preferably non-compressively dried to give a three-dimensional structure. The inherent stiffness of the wet elastic pulp fibers can be reduced, if desired, by the incorporation of a suitable plasticizer such as glycerol or by mechanical treatment such as micro-stretching, dry creping or calendering.

The dried fabrics in continuous form very suitable for the formation of the three-dimensional tissues are described in U.S. Patent No. 5,429,686 issued to Chiu et al., "Apparatus for Making Soft Tissue Products", issued July 4, 1995, incorporated herein by reference. Other methods such as wet molding, forming on three-dimensional forming fabrics, drying on non-woven substrates, rapid transfer onto engraving fabrics, engraving, stamping and the like can be used to create useful three-dimensional structures. The base sheet can be formed as a unitary multilayer structure in which several layers or strata are closely linked and intimately connected to one another. Unitary multi-layer base sheets can be formed using layered or layered head boxes in which two or more supplies are provided in separate chambers of a headbox, or these can be formed using separate headboxes by laying the wet fabrics together before drying in order to allow an extensive hydrogen bond to develop between the layers during drying, or these can be formed during air drying by varying the composition of the fibers and the additives imparted to the fabric. Multilayer sheets allow better control of physical properties by making the material composition of each layer. For example, a unitary multi-layer base sheet useful for the present invention would have an upper layer, corresponding to the upper surface of the base sheet, and at least one remaining layer below said upper and integrally joined layer to it, preferably through the hydrogen bonds formed between the cellulosic fibers during drying, wherein said top layer differs from at least one remaining layer of the base sheet in terms of composition of the material. The difference in material composition may be due to differences in fiber species (eg, percentage of hardwood versus softwood); fiber length; fiber performance; fiber treatment with processes which change fiber morphology or fiber chemistry such as mechanical refinement, fiber fractionation, dispersion to impart curl, vapor explosion, enzymatic treatment, chemical cross-linking, ozonation , bleaching, loading the lumen with fillers or other chemical agents, treatment with super critical fluid, including the extraction of supercritical fluid from agents in the fiber reservoir or super critical fluid solutions over and in the cell wall , and similar. The difference in material composition between the top layer and at least one other layer on the base sheet may also be due to differences in the aggregate chemicals, including the type, nature or dosage of the added chemicals. Chemistries differentially added to at least one layer of the fabric may include debonding agents, antibacterial agents, wet strength resins, starches, proteins, superabsorbent particles, fiber plasticizers such as glycols, dyes. the opacifiers, the surfactants, the zinc oxide, the caustic soda, the silicone compounds, the zeolites, the activated carbon and the like. In a preferred embodiment, the base sheet structure has a lower non-compressively dried, wet elastic layer, preferably composed of soft wood fibers, preferably including at least 10% high performance fiber such as BCTMP spruce, and a soft upper layer containing a part of finer fibers such as hardwoods chemically pulped. The multi-layer base sheet structure is unitary, meaning that the two layers are connected or joined together intimately, For example, a two-layer unitary base sheet can be formed with a layered head box or by laying together two wet sheets before drying to form an intimate contact and a hydrogen bond between the two layers.

The part of the surface area treated with hydrophobic materials must be large enough to provide an effective improvement in comfort, which in part depends on the specific product. Thus, the fraction of the base sheet surface covered by the hydrophobic material may be about 5% or more, more specifically about 10% or more, more specifically about 20% or more, more specifically about around 30% or greater, and even more specifically from around 40% to around 75%. The part of the surface area of the sheet base which remains essentially hydrophilic may be around 10% or greater, more specifically about 20% or more, more specifically about 30% or more, more specifically about 40% or more, more specifically from around 20% to around 90%, and even more specifically from around 50% to around 90%. For effective fluid removal, the lateral width of the depressed hydrophilic regions should be about 0.1 millimeters or greater, more specifically from about 0.5 millimeters or greater, and even more specifically from about 1 millimeter larger. The spacing between the depressed hydrophilic regions can be about 0.4 millimeters or greater, more specifically about 0.8 millimeters or greater, and even more specifically about 1.5 millimeters or greater. The minimum width of the raised regions may be about 0.5 millimeters or greater, or more specifically from about 1 millimeter or greater, and even more specifically from about 1 to about 3 millimeters.

In a preferred embodiment, the hydrophobic material comprises an essentially contiguous network of hydrophobic fibers having a plurality of macroscopic openings such that a portion of the depressed regions of the base sheet are aligned with openings in the superimposed network of hydrophobic fibers to allow to the exudates of the body to pass through the macroscopic openings until the leaf base. A macroscopic opening is defined as an opening that is large relative to the intrinsic pore size of the material. In a typical bonded or bonded knitted fabric, for example, a macroscopic opening will resemble the eye as being a deliberately introduced hole or hole in the fabric rather than a characteristic pore between two adjacent fibers, and specifically may have a characteristic width of about 0.2 millimeters or greater, of about 0.5 millimeters or greater, of about 1 millimeter or greater, of about 2 millimeters or greater, of about 4 millimeters or greater, of about 6 millimeters or greater, or from about 1 millimeter to about 5 millimeters. The characteristic width is defined as four times the area of the opening divided by the perimeter.

The non-woven fabric can be made of synthetic fibers, as is known in the art, and can be a spunbonded fabric, a meltblown fabric, a bonded and bonded fabric, or other fibrous non-woven structures known in the art. For example, a nonwoven polyolefin fabric such as a low base weight spunbonded material can be provided with openings through the pin opening; perf engraving and mechanical stretch of the tissue; punching die or embossing to provide openings or holes in the fabric; hydroentangling to impart openings by rearregulating the fibers due to the interaction of the water jets with the fibrous tissue to reside this on a three-dimensional or textured substrate with pattern that imparts a pattern to the tissue; water blades that cut desired openings or holes in the fabric; laser cutters that cut tissue parts; pattern forming techniques, such as air-laying synthetic fibers on a patterned substrate to impart macroscopic openings; needle punching with needle sets with spikes for hooking and moving fibers; and other methods known in the art. Preferably, the openings are provided in a regular pattern on at least a portion of the topsheet of the absorbent article.

Preferably, the openings in the network of hydrophobic fibers are spaced apart and in register with respect to the structure of the base sheet so that a predetermined fraction of the openings are greatly superimposed on the depressed regions of the base sheet. An opening is said to be fairly superimposed over a depressed region if at least half of the area of the macroscopic opening resides over a depressed region of the base sheet. The predetermined fraction of the openings that are mostly superimposed on the depressed regions can be about 0.25 or greater, 0.4 or greater, 0.5 or greater, 0.7 or greater, 0.8 or greater, or from about 0.4 a around 0.85. The contiguous network of hydrophobic matter is laminated to or physically bound in another way with the base sheet underlying. Preferably, the network of hydrophobic fibers is attached to the base sheet by means of adhesives and related agents, including hot melts, latexes, gums, starch, waxes, and the like, which adhere or bind to the upper regions of the base sheet with the adjacent parts of the superimposed network of hydrophobic fibers. Preferably, the adhesives are applied only to the highest portions of the base sheet to effect the bond between the hydrophilic base sheet and the network of hydrophobic fibers with the macroscopic openings therein., leaving the depressed regions essentially free of adhesives. The adhesive application can be through the application of meltblowing of hot melt adhesives and thermoplastic materials, swirl spray nozzles of melted or dissolved adhesives, printing of adhesive material on one or both surfaces before bonding, and the like. If the adhesives are applied directly to the base sheet by means of spraying, aerosol spray or drops in any form, before the contact of the base sheet with the hydrophobic material, then it is desirable to use a template or shield with pattern for avoiding the application of adhesive to the depressed regions of the base sheet and to ensure that the adhesives are applied preferentially to the raised portions of the base sheet.

For improved comfort, the hydrophobic fiber network used in the aforementioned embodiment preferably it is one that is perceived as soft and conformable when it is close to the skin.

For an optimum efficiency in the incorporation comprising a non-woven fabric, the openings in the fabric must be arranged in a pattern corresponding to the arrangement of the depressed regions in the tissue base sheet, or they must correspond to a subset of the regions depressed from the base sheet. The Applicant has found a useful means for providing perforations in a non-woven fabric in a pattern which corresponds geometrically to the depressed regions of the molded three-dimensional base sheet wherein the base sheet was molded onto a foraminous textured substrate such as a cloth. three-dimensional continuous dryer. The method involves hydroentanglement, which is a well-known principle involving the use of high-pressure water jets to modify a fibrous surface. The basic principles of the hydroentanglement are described by Evans in the patent of the United States of America number 3,485,706 granted in 1969, and in the patent of the United States of America number 3,494,821 granted in 1970, both of which are incorporated here for reference. The hydroentanglement, as is known in the art, can be used to impart perforations to a non-woven fabric. In a well-known technique, the non-woven fabric is carried on a textured permeable carrier fabric. The action of the jets of water on the non-woven fabric when residing is on the textured fabric makes the fibers are moved outwardly from the raised portions of the carrier fabric on which the non-woven fabric resides, resulting in openings in which the carrier fabric was raised. If a non-woven fabric is placed on the same kind of continuous dryer fabric that was used to mold a three-dimensional continuous dried sheet, preferably a non-creped or only lightly creped sheet in order to preserve the texture in the base sheet, then the high places on the carrier TAD fabric will become perforated regions in the non-woven base sheet. The upper parts of the TAD fabric will correspond to the depressed regions on the fabric side of the dried sheet in a continuous manner. Alternatively, if the non-woven fabric is hydroentangled against the underside of a three-dimensional TAD fabric, the raised regions on the underside of the TAD fabric will generally correspond to those depressed on the air side of the sheet that is continuously dried over TAD fabric. In either case, a non-woven fabric can be created having openings that align with the actual physical structure of the TAD fabric such as, with the depressed regions of a continuously dried sheet. When the perforated nonwoven material is then bonded to the continuously dried base sheet, the openings can be aligned with the depressed regions of the base sheet using techniques known in the art, such as photoelectric eyes or CCD cameras. high speed which can see the position of the openings in the non-woven fabric in relation to the position of the dried cloth in shape continuous when the two are put together, so that the position of a material can be adjusted both in the transverse direction and in the machine direction (for example by controlling the speed of a layer or by the movement of the machine direction of a roll not unrolled from a material) for a proper placement of the two layers together.

In embodiments comprising contiguous non-woven fabrics with spaced and spaced openings for fluid access to the hydrophilic base sheet, applicants have found that excellent fluid intake and absorbency results when the absorbent fabric is superimposed on a separate layer of moisture. densified fluff pulp or a cellulose tissue placed by air, preferably an air-laid fabric stabilized with heat-shrinkable materials or crosslinking chemistry such as Kymene moisture resistance resin. With densified cellulosic tissue beneath the base sheet and the hydrophobic material of the present invention, a discharge of fluid entering the hydrophilic base sheet can be pulled out of the hydrophilic base sheet by capillary suction provided the size The local pore of the underlying absorbent layer is sufficiently small. Experiments with dyed water and also with a mixture of aqueous egg white have shown that the combination of a hydrophobically treated cellulose base sheet resting on a fabric placed by densified air can result in a much improved intake, with the fluid being mainly directed inside the material placed by air and not spreading laterally significant in the base sheet.

It has also been found that highly calendered versions of such fabrics are suitable as hand towels. The originally higher hydrophobic regions are made relatively flat, offering significant hydrophilic areas initially in contact with moist skin for rapid fluid intake, but also having the ability to expand after wetting to provide an improved dry sensation upon retraction of hydrophilic areas. wetted from the skin in relation to the more hydrophobic raised regions. The fabrics thus treated can achieve the previously mutually exclusive objectives of having a high density for economic assortment and a low density once wetted for high absorbency, while also having a dry feel in use.

Thus, in one aspect, the invention resides in an absorbent fabric having a dry feel when wetted, comprising: (a) an inherently hydrophilic base sheet comprising fibers for making paper and having a top surface and a lower surface, said upper surface has elevated and depressed regions; and (b) matter hydrophobic deposited preferably on the elevated regions of the upper surface of the base sheet.

In another aspect, the invention resides in a zoned fabric in a dual absorbent form that provides a dry feel in use, said fabric having an upper surface comprising a plurality of hydrophobically treated regions surrounded by inherently hydrophilic cellulosic regions, wherein upon wetting said The tissue expands so that the hydrophobically treated regions are preferably raised relative to the hydrophilic regions.

In another aspect, the invention resides in an absorbent fabric having a rewet value of about 1 gram or less, comprising: (a) an inherently hydrophilic base sheet comprising fibers for making paper and having a top surface and a lower surface, said upper surface has high and depressed regions with a Global Surface Depth of 0.2 millimeters or greater in the uncalendered or non-creped state, said base sheet furthermore has a wet compressed volume of at least 6 cc / g; and (b) hydrophobic material deposited preferably on the elevated regions of the upper surface of the base sheet.

In another aspect, the invention resides in a fabric absorbent having a dry sensation when wetted, comprising: (a) an inherently hydrophilic base sheet comprising fibers for making paper and having a top surface and a bottom surface, said top surface having high and depressed regions with a depth of Global Surface of about 0.2 millimeters or greater; and (b) an essentially contiguous network of hydrophobic fibers having a plurality of macroscopic openings attached to the upper surface of said base sheet so that a portion of the depressed regions of the base sheet are aligned with the openings in the network overlying hydrophobic fibers to allow exudates from the body to pass through the macroscopic openings to the base sheet.

In another aspect, the invention resides in an absorbent fabric having a dry feel when wetted, comprising: (a) an inherently hydrophilic base sheet comprising fibers for making paper and having an upper surface and a lower surface, said upper surface has high and depressed regions, said base sheet preferably has a wet tension: dry ratio of at least 0.1; and (b) a contiguous network of hydrophobic material deposited preferably on the raised regions of the upper surface of said base sheet.

In another aspect, the invention resides in a absorbent article comprising a liquid impermeable bottom sheet, a cellulosic absorbent core in a superimposed relation with said bottom sheet, and a liquid permeable absorbent fabric, said absorbent fabric comprises an inherently hydrophilic base sheet comprising fibers for making paper and has a ratio of wet tension: in dry of at least 0.1, said base sheet has an upper surface and a lower surface, said upper surface has elevated and depressed regions and hydrophobic material deposited preferably over the elevated regions, where the base sheet is superimposed on the absorbent core with the lower surface of said base sheet facing the absorbent core.

In another aspect, the invention resides in an absorbent article comprising a liquid impermeable bottom sheet, a cellulosic absorbent core in a superimposed relationship with said bottom sheet, and a liquid permeable absorbent fabric, said absorbent fabric comprising a base sheet inherently hydrophilic comprising fibers for making paper, said base sheet has an upper surface and a lower surface, said upper surface has elevated and depressed regions, further comprises a perforated contiguous fabric of hydrophobic nonwoven material bonded to the upper surface of the sheet base such that a portion of said openings cover the depressed regions of the base sheet, in wherein the base sheet is superimposed on the absorbent core with the bottom surface of the base sheet facing the absorbent core.

In another aspect, the invention resides in calendared low density structures of the previously three dimensional elastic fabrics having hydrophobic material over regions that had once been superior to one of both sides of the fabric. Without limitation, such articles can serve as suitable hand towels by providing a high initial intake of fluid by the plurality of hydrophilic regions in the plane of the flat paper during the initial transmission, followed by an increased dry sensation when the treated areas are raised. Dry feeling outside the plane of the leaf during wetting. The hydrophobic material in such articles may also be used to increase the smooth lubricity of the article and may be applied contiguously or non-contiguously.

In another aspect, the invention resides in a method for producing a take-up material for an absorbent article, comprising the steps of (a) forming an embryo-paper web from an aqueous solution of paper-making fibers; (b) continuous drying of the embryonic tissue tissue on a three-dimensional continuous drying fabric having a pattern of elevated and depressed regions; (c) complete the drying of tissue; (d) piercing a non-woven fabric by means of hydroentanglement, wherein the non-woven fabric lies on a carrier sheet having essentially the same pattern of elevated and depressed regions as the continuous drying cloth of the country (b); and (e) attaching the perforated nonwoven fabric to the continuously dried paper fabric so that the openings of the nonwoven fabric are substantially aligned with the depressed regions of the continuously dried paper fabric.

By saying that the hydrophobic matter is preferably deposited on the elevated portions of the base sheet, the term "preferably" implies that more hydrophobic material is deposited on the higher regions than on the depressed regions, in terms of a base of more. per unit area, so that the depressed regions have a significantly lower amount of hydrophobic matter present than the elevated regions. It is preferred that the percentage of the hydrophobic material deposited over the high regions be at least about 60 percent, more specifically at least about 70 percent, even more specifically at least about 80 percent of the total amount deposited. The hydrophobic material may comprise fine fibers, powders, resins, gels and other materials, preferably applied with an average surface basis weight of less than 10 grams per square meter, more specifically from about 1 to about 10. grams per square meter. When used as the skin contact layer of absorbent articles, said absorbent fabric serves as an absorbent enhancement over non-absorbent plastic perforated films or other inherently hydrophobic materials. The raised regions of said base sheet preferably comprise between about 5 and about 300 protuberances per square inch having a height relative to the plane of the base sheet, as measured in the uncalendered state of about 0.1 millimeters or more , preferably of about 0.2 millimeters or more, more preferably of about 0.3 millimeters or more, and more preferably from about 0.25 to about 0.6 millimeters.

Definition of Test Terms and Procedures In the description of the tissues of this invention and their fluid handling characteristics, a number of terms and tests were used which are described below.

As used herein, the phrase "high performance pulp fibers" are those fibers for making pulp paper produced by pulping processes that provide a yield of about 65 percent, or more, more specifically about 75 percent. percent or more and even more specifically from about 75 to about 95 percent. The yield is the resulting quantity of the processed fiber expressed as a percentage of the initial mader mass. High performance pulps include bleached quimotermomechanical pulp (BCTMP); the quimotermomecánica pulp (CTMP) the pressure / pressure thermomechanical pulp (PTMP), the thermomechanical pulp (TMP), the chemmicothermomechanical pulp (TMCP), the high yield sulfite pulps, and the high yield kraft pulp, all of which contain fibers that have high levels of lignin. The preferred high-performance pulp fibers can also be characterized as being composed of relatively n damaged and comparatively complete fibers, having a freedom of freedom of Canadian standard freedom (CSF) of 250 or more, more specifically of 350 CSF or greater, and still more specifically d 400 CFS or higher, and a low fines content (less than 25 percent, more specifically less than 20 percent, even more specifically less than 15 percent, and even more specifically less than 10 percent). cent through the Britt agitation test). In addition to the papermaking fibers listed above, the high performance pulp fibers also include other natural fibers such as silk fibers of benzenetose seed, abaca, hemp, soft reed, bagasse, cotton and the like. .

As used herein, "wet elastic pulp fibers" are fibers for making paper selected from the group it comprises high performance fibers, chemically entwined fibers and cross-linked fibers. Examples of chemically entwined fibers or linked fibers er. cross-linked include mercerized fibers, HBA fibers produced by Weyerhaeuser Corporation and those as described er. U.S. Patent No. 3,224,926, "Method of Formation of Crosslinked Crosslinked Cellular Fibers and Products thereof", granted in 1965 to LJ Bernardin and U.S. Patent No. 3,455,778, "Creped Tissue Formed of Fibers Linked in a Rigid Cross Form and Fibers for Making Refined Paper", awarded in 1969 to LJ Bernardin. Although any mixture of wet elastic pulp fibers can be used, high performance pulp fibers are the wet elastic fiber of choice for many embodiments of the present invention because of their low cost and good fluid handling performance when used in accordance with to the principles described below.

The fibers of moist elastic pulp or of alternative performance in the base sheet can be at least about 10 percent by dry weight or greater, more specifically about 15 percent by dry weight or greater, more specifically from about 30 percent by dry weight or greater, even more specifically from about 50 percent by dry weight or greater, and even more specifically from about 20 to 100 percent. For the base sheets in layers, these same quantities can be applied to one or more of the individual layers. Because wet elastic pulp fibers are generally softer than other papermaking fibers, in some applications it is advantageous to incorporate them into the middle of the final product, such as placing them in the center layer of a three-layer base sheet or, in the case of a product of two strata, place them in the inward facing layers of each of the two strata.

The "water retention value" (WRV) is a measure that can be used to characterize some fibers useful for the purposes of this invention. The water retention value is measured by supplying 0.5 grams of fibers in deionized water, soaking for at least 8 hours, and then centrifuging the fibers in a 1.9-inch diameter tube with a 100-mesh grid at the bottom of the tube at 1000 G for 20 minutes. The samples are weighed, then dried at 105 degrees centigrade for 2 hours and then weighed again. The water retention value is (wet weight-dry weight) / dry weight. The high performance pulp fibers may have a water retention value of about 0.7 or greater and typically have a water retention value of about 1 or greater and preferably from about 1 to about 2. The bonded fibers Low-through cross-type typically have a water retention value of less than about 1, specifically less than about 0. 7 and more specifically still less than around 0.6"Rewetting" is a measure of the amount of liquid water which can be transmitted out of a wetted tissue to an adjacent dry filter paper and is intended to estimate the tendency of a wetted fabric to wet the skin. The rewet test is carried out by cutting a sample of a tissue from tissue to a rectangle of dimensions of 4 inches by 6 inches. The test was carried out in a room conditioned Tappi (50% RH, 73 degrees F). The initial dry weight of the conditioned sample is recorded, then the deionized water is sprayed on both sides of the tissue sample to wet it uniformly, bringing the total wet mass of the tissue to a value of 4 times the initial dry weight. previously recorded the sample, thus carrying the "apparent moisture content" of the sample to a value of 3.0 grams (+ 0.15 g) of water added per gram of dry fiber to the conditioned air. The process of repeatedly spraying and weighing the sample until the proper mass has been reached should not take more than 2 minutes. Once the sample is moistened, a single dry Whatman # 3 filter, whose mass has been measured and recorded, was placed over the center of the wet tissue sample and a load is immediately placed on the filter disc. The load is an aluminum cylindrical disk that has a diameter of 4.5 inches and a thickness of 1 inch for a mass of 723 g. The aluminum disc should be centered around of the filter disk. The filter paper on the wet sample remains under load for 20 seconds, at which time the load and the filter paper are immediately removed. The filter paper is then weighed, and the additional mass relative to the dry mass in initial air is carried in grams as the rewet value.

"The standardized rewet" is the rewet value of a sample divided by the conditioned dry mass of the sample.

"Absorbency at 0.075 pounds per square inch" is a measure of the absorbent capacity of the lower sheet under a load of 0.075 pounds per square inch. The test requires two metal plates cut to a length of 6 inches and a width of 4 inches. A lower plate is 0.125 inches thick and the top plate is three quarters of an inch thick of aluminum having a mass of 813 grams, which imparts a load of 0.075 pounds per square inch when placed flat on a tissue sample . The center of the top plate has a cylindrical hole 0.25 inches in diameter. To carry out the test, samples of 4 inches by 6 inches of dry tissue were cut, with the length of 6 inches being aligned in the machine direction. The multiple tissue strata are stacked to achieve a tissue stack weight as close to 2.8 grams as possible. possible. The tissue stack is placed between the two horizontal plates which lie flat on a larger tray. A graduated cylinder by volumetric analysis with 50 ml of deionized water is directly aligned above the hole in the upper plate. The test piece opens and the water is allowed to slowly enter the hole in the top plate so that the hole is filled with a column of water that is kept as high as possible without rising up or spilling on the upper surface of the water. license plate. This is done until the sample is apparently saturated. The apparent saturation is the point at which the water begins to leave any edge of the sample. The mass of water that has been removed from the specimen is taken as the value for "Horizontal Absorbency at 0.075 pound per square inch." At this point, the tray containing the plates is tilted at an angle of 45 degrees for 30 seconds to allow some of the liquid to drain into the sample. The most of any liquid that drains out is subtracted from the value "d Horizontal Absorbency at 0.075 pounds per square inch" prior to giving an "Inclined Absorbency at 0.075 pounds per square inch". For the base sheet, the horizontal absorbenci at 0.075 pounds per square inch can be about 5 g or greater, or alternatively 7 grams or more, 9 grams or more, 11 grams or greater, or from about 6 grams. grams to around 10 grams. Absorbency tilted to 0.075 pounds per square inch may be around g or greater, about 6 g or greater, about 8 g or greater, of about 10 g or greater, or from about 6 to about 10 g. The tilted absorbency of the cover may be about 5 to 40% less than that of the base sheet alone, while the horizontal absorbency may be higher or lower than that of the base sheet.

"Fabric side" of a weave of paper dried through air is the side of the fabric that was in contact with the dryer fabric through air (TAD fabric) during continuous drying. Typically the fabric side of a continuously dried sheet offers the most pleasing touch properties for skin contact.

The "air side" of a paper fabric dried through air is the side of the fabric that was not in contact with the continuous air drying fabric (TAD fabric) during continuous drying. Typically, the air side of a continuously dried sheet feels somewhat more gritty than the fabric side of the sheet itself.

The "density" can be determined by measuring the caliper of a single sheet using a TMI tester (from Testing Machines, Inc., of Amityville, New York) with a load of 0.289 pounds per square inch, for example, using a TMI model 49-70 with an enlarged plate. The density is calculated by dividing the caliber by the base weight of the blade. The base sheets useful for the purposes of this invention may have essentially uniform and low densities (high volume) which is preferred for wet laid structures, or may have a variable density zone distribution, which is preferred in the base sheets placed by air. The substantial density uniformity is achieved, for example, by continuous drying to a final dryness if the fabric is differentially compressed. In general, the density of the base sheets of this invention may be about 0.3 grams per cubic centimeter (g / cc) or less, more specifically about 0.15 g / cc or less, even more specifically about 0.1. g / cc or less and can be from about 0.05 to 0.3 g / cc or from about 0.07 to 0.2 g / cc. It is desirable that the base sheet structure, once formed, be dried without essentially reducing the number of elastic and wet fiber bonds d. Continuous drying, which is a common method for drying tissues and towels, is a preferred method to preserve the structure. The base sheets made by wet-laying followed by continuous-form drying typically have a density of about 0.1 grams per cubic centimeter, while the air-laid sheets normally used for the diaper erasure typically have densities of about 0.05 grams per cubic centimeter. All those base sheets are within the scope of the invention.

As used herein, the "dry volume" is measured with a thickness gauge having a circular plate 3 inches in diameter so that a pressure of 0.05 pounds per square inch is applied to the sample, which must be conditioned to 50% relative humidity and 73 degrees F for 24 hours before measurement. The base sheet as well as the uncalendered fabric may have a dry volume of 3 cubic centimeters per gram or more, preferably 6 cubic centimeters per gram or more, more preferably 9 cubic centimeters per gram or more, more preferably 11 cubic centimeters or more. cubic centimeters per gram or more, and more preferably between 8 cubic centimeters per gram and 28 cubic centimeters per gram.

"Wet strength agents" are materials used to immobilize the bonds between the fibers in the wet state. Typically the means by which the fibers are held together in the paper and in the tissue products involve the hydrogen bonds and sometimes the combinations of the hydrogen bonds and the covalent and / or ionic bonds. In the present invention, it is desirable to provide a material that will allow the bonding of fibers in a manner such as to immobilize fiber-to-fiber attachment points and to make them resistant to disruption in the wet state. In this case the wet state will usually be when the product is very saturated with water or other aqueous solutions, but it can also mean a considerable saturation with body fluids such as urine, blood, mucus, menstrual fluids, fluid bowel movements, lymph and other exudates from the body.

There are a number of materials commonly used in the paper industry to impart wetting resistance to paper and cardboard that are applicable to this invention. These materials are known in the art as "wet strength agents" and are commercially available from a wide variety of sources. Any material that when added to a tissue or sheet of paper results in providing the sheet with a ratio of wet geometric stress strength: resistance to dry geometric stress in excess of 0.1 will be called, for the purposes of this invention a agent of resistance to moisture. Typically these materials are called either permanent wet strength agents or as "temporary" wet strength agents. For the purposes of a permanent differentiation of temporary wet strength, permanent will be defined as those resins which, when incorporated into paper or tissue products, will provide a product that retains more than 50% of its original wet strength after of exposure to water for a period of at least 5 minutes. Temporary wet strength agents are those which show less than 50% of their resistance to original wetting after being saturated with water for 5 minutes. Both kinds of material find application in the present invention. The amount of wet strength agent added to the pulp fibers can be at least about 0.1 percent by dry weight, more specifically about 0.2 percent by dry weight or more, and even more specifically from about 0.1 to about 3 percent by dry weight based on the dry weight of the fibers.

The permanent wet strength agents will provide a more or less long term wet elasticity to the structure. In contrast, temporary wet strength agents will provide structures that have low density and high elasticity, but will not provide a structure that has a long-term resistance to exposure to water or body fluids. The mechanism through which the wet strength is generated has little influence on the products of this invention as long as the essential property of generating water resistant bond at the fiber / fiber bonding points is obtained.

Suitable permanent wet strength agents are typically cationic oligomeric or polymeric resins typically soluble in water which are capable of either cross-linking with themselves (as a crosslinking) or with cellulose or other constituent of wood fiber. The most widely used materials for this purpose are the class of polymer known as polyamide-polyamine-epichlorohydrin (PAE) res resins. These materials have been described in the patents issued to Keim (United States of America numbers 3,700,623 and 3,772,076) and are sold by Hercules, Inc., of Wilmington Delaware, as KIMENE 557H. The related materials are marketed by Henkel Chemica Company of Charlotte, North Carolina and Georgia-Pacifi Resins, Inc., of Atlanta Georgia.

Polyamide-epichlorohydrin resins are also useful as binding resins in this invention. The materials developed by Monsanto and marketed under the SANTO RES label are activated polyamide-epichlorohydrin d-base resins that can be used in the present invention. These materials are described in the patents issued to Petrovic (Patents of the United States of America numbers 3,885,158 3. 899,388; 4.129.528 and 4.147586) and Van Eenam (patent of the United States of America number 4,222,921). Although these n are commonly used in consumer products, the polyethylene imine resins are also suitable for immobilizing the binding sites in the products of this invention. Another class of wet strength agents of the permanent type are exemplified by the aminoplast resins obtained by the reaction of formaldehyde with melamine or urea.

Temporary Resistance Resins Suitable include but are not limited to resins that have been developed by American Cyanamid and that are marketed under the name PAREZ 631 NC (now available from Cytec Industries, West Paterson, New Jersey). These and similar resins are described in U.S. Patent No. 3,556,932 to Coscia et al. And in U.S. Patent No. 3,556,933 to Williams et al. Other temporary wet strength agents which find application in this invention include the modified resins such as those available from National Starch and marketed as CO-BOND 1000. It is believed that these and the related starches are described in the US Pat. America number 4,675,394 granted to Solarek and others. Derivatized dialdehyde starches as described in the Japanese Patent of Kokai Tokkyo Koho JP 03,185,197, may also provide a temporary wetting resistance. Other temporary wet strength materials such as those described in U.S. Patent Nos. 4,981,557; 5,008,344 and 5,085,736 issued to Bjorkquist will also be of use in this invention. With respect to the classes and types of moisture resistant resins listed, it should be understood that this listing is merely to provide examples and is not meant to exclude other types of wet strength resins, nor is it meant to limit the scope of this invention.

Although the wet strength agents as described above find a particular advantage to be used in connection with this invention, other types of bonding agents can also be used to provide the necessary wet elasticity. These can be applied at the wet end of the base sheet manufacturing process or applied by spraying or printing, etc., after the base sheet is formed or after it is dried.

"Non-compressive drying" refers to drying methods for drying cellulosic tissues that do not involve compressive pressure points or other steps causing significant compression or densification of a part of the tissue during the drying process. Such methods include drying through air; the blow drying of air jet; non-contact drying such as flotation drying in air, as taught by E.V. Bowden, E.V. Appita J., 44 (1): 41 (1991); a continuous flow or blow of steam super heated; microwave drying and other radiofrequency or dielectric drying methods; water extraction by super critical fluids; water extraction by non-aqueous low surface tension fluids; infrared drying; dried by contact with a film of melted metal; and other methods. It is believed that the three-dimensional base sheets of the present invention can be dried with any of the aforementioned non-compressive drying means without causing tissue densification significant or significant loss of its three-dimensional structure and its wet elastic properties. The normal dry crepe technology is seen as a method of compressive drying since the fabric must be pressed mechanically over part of the dryer surface, causing a significant densification of the pressed regions on the heated Yankee cylinder. The technology for compressively draining and drying tissue tissues with an air press and optionally with a Yankee dryer operated without a crepe is described in the following patent application copendient commonly assigned from the United States of America series unknown number "Method to Produce Low Density Elastic Fabrics "by FG Druecke et al., Attorney's issue number 13,504, filed on October 31, 1997, United States of America patent application with unknown serial number" Elastic Low Density Fabrics and Methods for Making Ta Tejido "by S. Chen et al., Issue of attorney number 13,381 filed on October 31, 1997; patent application of the United States of America series number 08 / 647,508, filed on May 14, 1996 by MA Hermans et al entitled "Method and Apparatus for Making a Soft Tissue", and patent application of the United States of America with unknown serial number filed on October 31, 1997 entitled "Air Press to Drain a Wet Tissue" by F. Hada and others, all of which are incorporated herein by reference. It is also of a potential value for useful tissue manufacturing operations and the present invention the paper machine described in the patent of the United States of America number 5,230,776 granted on July 27, 1993 to I. A. Anderson and others; and the capillary drainage techniques described in the patents of the United States of America numbers 5,598,643 granted on February 4, 1997 and 4,556,450 granted December 3, 1985 both to SC Chuang and others all of which are incorporated herein by reference. The drainage concepts described by J. D. Lindsay in "Drainage with Displacement to Maintain Volume" by Paperi ja Puu, 74 (3): 232-242 (1992) are also of potential value.

As used herein, the "wet: dry ratio" is the ratio of the geometric mean wet tensile strength divided by the geometric mean dry tensile strength. The resistance to the geometric mean tension (GMT) is the square root of the product of the tensile strength in the machine direction and the tensile strength in the cross-machine direction of the fabric. Unless stated otherwise, the term "tensile strength" means "resistance to geometric mean stress". The base sheets of this invention preferably have a wet: dry ratio of about 0.1 or greater, more specifically about 0.15 or greater, more specifically about 0.2 or greater, even more specifically about 0.3 or greater, and even more specifically from around 0.4 or greater, and even more specifically from around 0.2 to around 0.6.

The tensile strengths can be measured using an Instron tensile test using a 3-inch jaw width, a 4-inch jaw extension and a cross-head speed of 10 inches per minute after keeping the sample under TAPPI conditions. 4 hours before the test. For increased integrity and wetness, the base sheets of this invention preferably also have a minimum absolute ratio of dry tensile strength to the basis weight of about 1 gram / gram per square meter, preferably from about 2 grams per square meter. grams / gram per square meter, more preferably about 5 grams / gram per square meter, more preferably about 10 grams / gram per square meter and even more preferably about 20 grams / gram per square meter and preferably from about around 15 to 50 grams / gram per square meter.

The "global surface depth". A leaf of base or three-dimensional fabric is a leaf with a significant variation in the surface elevation due to the intrinsic structure of the leaf itself. Since aguí was used, this elevation difference is expressed as the "Global Surface Depth". The base sheets useful for this invention possess three-dimensionality and have a Global Surface Depth of about 0.1 millimeters or greater, more specifically d about 0.3 millimeters or greater, even more specifically about 0.4 millimeters or greater, even more specifically about 0.5 millimeters or greater, and even more specifically from about 0.4 to about 0.8 millimeters.

The three-dimensional structure of a mostly planar sheet can be described in terms of its surface topography. Rather than presenting an almost flat surface, as is typical of conventional paper, the molded sheets useful in the production of the present invention have significant topographic structures which, in one embodiment, may derive in part from the use of the continuous drying fabrics sculpted such as those taught by Chiu et al. in U.S. Patent No. 5,429,686, previously incorporated by reference. The resulting base sheet surface topography typically comprises a regular repeating unit cell that is typically a parallelogram with sides between 2 and 20 millimeters in length. For wet laid materials, it is preferred that these three three-dimensional base sheet structures be created by molding the wet sheet or be created before drying, rather than by creping or etching or other operations after the sheet has been laid. drying In this way, the three-dimensional base sheet structure is more likely to be well retained after wetting, helping to provide high moisture resistance and to promote good plane permeability. For the base sheets placed by air, the structure can be imparted by of thermal etching of a fibrous mat with binder fibers that are activated by heat. For example, a fibrous mat placed by air containing thermoplastic or hot-melt binder fibers can be heated and then etched before the structure is cooled to give the sheet a three-dimensional structure.

In addition to the regular geometric structure imparted by the sculpted fabrics and other fabrics used in the creation of the base sheet, an additional fine structure, with a full length scale of less than about 1 millimeter, may be present in the base sheet. Such a fine structure can be derived from micro-beams created during the differential velocity transfer of the fabric from one fabric or wire to another before drying. Some of the materials of the present invention, for example, appear to have a fine structure with a fine surface depth of 0.1 millimeters or more, and sometimes 0.2 millimeters or more, when high profiles are measured using an interferometer system commercial moire. These fine peaks have a typical average width less than 1 millimeter. The fine structure of differential speed transfer and other treatments can be useful to provide additional softness, flexibility and volume. The measurement of the surface structures is described below.

A particularly suitable method to measure the Global Surface Depth is the moire interferometry which allows an accurate measurement without deformation of the surface. For reference to the materials of the present invention, surface topography should be measured using a moire-switched interferometer of a computer-controlled white light field with around a 38-millimeter field of view. The principles of a useful implementation of such a system are described in Bieman et al. (L. Bieman, K. Harding, and A. Boehnlein, "Absolute Measurement Using Moiré Changed Field" Procedures of the SPIE Optical Conference, volume 1614, pages 259-264, 1991). A suitable commercial instrument for moire interferometry is the CADEYES® interferometer produced by Medar, Inc. (of Farmington Hills, Michigan), built for a field vision of 38 millimeters (a field of vision within the range of 37 to 39.5 millimeters is suitable) . The CADEYES® system uses white light which is projected through a grid to project fine black lines onto the surface of the sample. The surface is seen through a similar grid, creating moiré edges that are seen by a CCD camera. Suitable lenses and a stepping motor adjust the optical configuration for the field change (a technique described below). A video processor sends captured edge images to a PC computer for processing, allowing the details of the surface height to be calculated back from the edge patterns seen by the video camera.

In the moire CADEYES interferometry system, each pixel in the CCD video image is said to belong to a moiré limit that is associated with a particular height range. The field change method, as described by Bieman others (L. Bieman, K. Harding and A. Boehnlein, "Absolute Measurement Using Moiré Changed Field", Proceedings of the SPIE Optical conference, volume 1614, pages 259-264 , 1991) and as originally patented by Boehnlein (U.S. Patent No. 5,069,548 incorporated herein by reference), is used here to identify the boundary number for each point in the video image (indicating at what limit one point belongs). The limit number is necessary to determine the absolute height in the measurement of point in relation. to a reference plane. A field change technique (sometimes called a phase change in art) was also used for the sublimit analysis (exact determination of the height of the measurement point within the height range occupied by the limit). These field change methods coupled with camera-based interferometry is an approach that allows accurate and absolutely rapid height measurement, allowing a measurement to be made despite the possible height discontinuities at the surface. The technique allows the absolute height of each of the discrete points of approximately 250,000 (pixels) on the sample surface to be obtained, if suitable optics are used, video devices, data acquisition equipment and software that incorporate the principles of moire interferometry with field change. Each measured point has a resolution of approximately 1.5 microns in its height measurement.

The computerized interferometer system is used to acquire topographic data and then generate a gray scale image of the topographic data, said image will be called "the height map" from now on. The height map is displayed on a computer television, typically in 256 shades of gray and is based quantitatively on the topographic data obtained for the sample being measured. The resulting height map for the measuring area of 38 square millimeters should contain approximately 250,000 data points corresponding to approximately 500.00 pixels in both the horizontal and vertical directions of the height map displayed. The pixel dimensions of the height map are based on a 512 by 512 CCD camera which provides moire pattern images on the sample which can be analyzed by the computer software program. Each pixel in the height map represents a height measurement at the corresponding location x and y on the sample. In the recommended system, each pixel has a width of approximately 70 microns, (for example it represents a region on the sample surface of about 70 microns long in both directions in an orthogonal plane). This level of resolution prevents the unique fibers that are projected above the -surface have a significant effect on the measurement of surface height. The measurement of height in the measurement z must have a nominal accuracy of less than 2 microns and a range in the z direction of at least 1.5 millimeters. (For an additional background on the measurement method, see CADEYES Product Guide, Medar, Inc., of Farmington Hills, Michigan, 1994, or other CADEYES manuals and publications of Medar, Inc.).

The CADEYES system can measure up to 8 moiré limits, each limit being divided into 256 depth counts (Sublimit height increments, the smallest resolvable height difference). There will be 2,048 height accounts over the measurement range. This determines the range in the total z-direction, which is approximately 3 millimeters in the 38 millimeter field of view instrument. If the variation of height in the field of vision covers more than 8 limits, a wrapping effect occurs around, in which the ninth limit is labeled as if it were the first limit and the tenth limit is labeled as the second limit. In other words, the measured height will be changed by 2,048 depth counts. The exact measurement is limited to the main field of 8 limits.

The moiré interferometer system, once installed and calibrated at the factory to provide the accuracy and range in the z-direction indicated above, can provide accurate topographic data for such materials like paper towels. (Those skilled in the art can confirm the accuracy of factory calibration by performing measurements on surfaces with known dimensions). The tests are carried out in a room under Tappi conditions (73 degrees F, 50% relative humidity). The sample should be placed flat on a surface that is aligned or almost aligned with the measuring plane of the instrument and should be at such a height that both the lowest and highest regions of interest are within the measurement region of the instrument.

Once properly placed, data acquisition is initiated using a Medar personal computer program and a height map of 250,000 data points is acquired and displayed, typically within 30 seconds of the start of the data acquisition time. (Using the CADEYES® system, the "threshold-contrast level" for noise rejection is set to number 1, providing some rejection of noise without excessive rejection of data points). The data reduction and the exhibition are achieved using a CADEYES® program for PC which incorporates an interface based on the Microsofe Visual Basic Professional for Windows program (version 3.0). The visual basic interconnection allows users to add tools and analysis to the order.

The height map of the topographic data can then be used by those skilled in the art to identify the characteristic unit cell structures (in the case of structures created by cloth patterns, these are typically parallelograms arranged as tiles to cover a large two-dimensional area) and to measure the depth from peak to valley typical of such structures. A simple method to do this is to extract height profiles of two dimension lines drawn on the topographic height map which pass through the highest and lowest areas of the unit cells. These height profiles can then be analyzed for the peak-to-valley distance, if the profiles are taken from a leaf or part of the leaf that was lying relatively flat when measured. To eliminate the occasional optical noise effect and possible outcroppings, the highest 10% and the lowest 10% of the profile must be excluded, and the height range of the remaining points is taken as the surface depth. Technically, the procedure requires calculating the variable that we call "PlO defined in the height difference between 10% and 90% of the material lines, with the concept of material lines being well known in art, as explained by L. Mummery, in the work Surface Texture Analysis: The Manual, Hommelwerk GmbH, Mühlhausen, Germany, 1990. In this approach, which will be illustrated with respect to Figure 7, surface 3 is seen as a transition from air 32 to material 33 For a given profile 30, taken from a sheet that lies flat, l The largest height at which the surface begins-the height of the highest peak-is the elevation of the "0% reference line" 34 or the "0% material line" meaning that 0% of the length of the horizontal line at that height is occupied by the material. Along the line that passes through the lowest point of the profile, 100% of the line is occupied by material, making the line "100% material line" 35. Between the material lines of 0% and 100 % (between the maximum and minimum points of the profile), the fraction of the horizontal line length occupied by the material will increase monotomically as the elevation line decreases. The material proportion curve 36 gives the relationship between the material fraction along a horizontal line that passes through the profile and the height of the line. The material proportion curve is also the cumulative height distribution of a profile. (A more accurate term could be a "material fraction curve").

Once the material ratio curve is established, one can use it to define the characteristic peak height of the profile. The "typical peak-to-valley height" parameter PlO is defined as the difference 37 between the heights of 10% of material line 38 and 90% of material line 39. This parameter is relatively robust in the sense that Outcrops or unusual departures of the typical profile structure have little influence on PlO height. The units of PlO are in millimeters. The The overall surface depth of a material is reported as the PlO surface depth value for the profile lines spanning the height extremes of the typical unit cell of that surface. The "fine surface depth" is the PlO value for the profile taken along a plateau region of the surface which is relatively uniform in height relative to the profiles covering a maximum or a minimum of the unit cells. The measurements are reported for the more texturized side of the base sheets of the present invention, which is typically the side that was in contact with the dried cloth continuously when an air flow is to the continuous dryer. Figure 8 depicts a profile of Example 13 of the present invention, discussed below, having a global surface depth of about 0.5.

The global surface depth is intended to examine the topography produced in the base sheet, especially those characteristics created in the sheet before and during the drying processes, but it is intended to exclude the large-scale topography created "artificially" from the operations of dry conversion such as engraving, drilling, folding, etc. Therefore, the profiles examined should be taken from the non-engraved regions if the base sheet has been recorded, or should be measured on a non-engraved base sheet. The global surface depth measurements exclude large-scale structures such as folds or bends which do not reflect the three-dimensional nature of the base sheet itself. It is recognized that leaf topography can be reduced by calendering and other operations which affect the entire base sheet. The overall surface depth measurement can be appropriately performed on calendered base sheet.

The "Wet Wrinkle Recovery Test" is a slight modification of the AATCC 66-1990 test method taken from the Technical Manual of the American Association of Textile Chemists and Colorists (1992), page 99. The modification is that of first moistening samples before carrying out the method. This is done by soaking the samples in water containing 0.01% wetting agent TRITON X-100 (from Rohm &Haas) for five minutes before the test. The sample preparation was carried out at 73 degrees F and 50% relative humidity. The sample is gently removed from the water with tweezers, drained by pressing it between two pieces of blotting paper with 325 grams of weight, and placed in the sample holder to be tested as with the wrinkle recovery test method. dry. The test measures the highest recovery angle of the sample being tested (in any direction, including machine direction and cross machine direction), with 180 degrees representing total recovery. The wet wrinkle recovery, expressed as percent recovery, is the recovery angle measured divided by 180 degrees, multiplied by 100. The base sheets of this invention may exhibit a wet wrinkle recovery of about 60% or greater, more specifically about 70% or greater, and will more specifically be about 80% or greater.

"Wet compressive elasticity" of the base sheets was defined by several parameters and can be demonstrated using a material property process that encompasses both wet and dry characteristics. A programmable resistance measuring device is used in the compression mode to impart a specified series of compression cycles for a dried conditioned sample initially, after which the sample is carefully moistened in a specified manner and subjected to the same sequence of compression cycles. While the comparison of wet and dry properties is of general interest, the most important information in this test relates to wet properties. The initial test of the dry sample can be seen as a conditioning step. The test sequence begins with the compression of the dry sample at 0.025 pounds per square inch to obtain an initial thickness (cycle A) after two load repetitions of up to 2 pounds per square inch followed by the discharge (cycles B and C).

Finally, the sample is again compressed at 0.025 pounds per square inch to obtain a final thickness (cycle D). (The details of the procedure, including the compression rates are given below). After sample treatment dry, the moisture was applied uniformly to the sample using a fine breeze of deionized water to bring the moisture ratio "g water / g dry fiber" to about 1.1. This is done by applying 95-110% of added moisture, based on the conditioned sample mass. This puts the typical cellulosic materials in a range of moisture where the physical properties are relatively insensitive to the moisture content (for example, the sensitivity is much lower than that for the moisture proportions of less than 70%). The moistened sample is then placed in the test device and the compression cycles are repeated.

Three measurements of wet elasticity are considered which are relatively insensitive to the number of sample layers used in the stack. The first measurement is the volume of the wet sample at 2 pounds per square inch. This is referred to as the "Wet Compressed Volume" (WCB). The second measurement is called the "Return Wet Bounce Rate" (WS), which is the ratio of the moisture sample thickness to 0.025 pounds per square inch at the end of the compression test (cycle D) to the thickness of the moisture sample at 0.025 pounds per square inch measured at the beginning of the test (cycle A). The third measurement is the "Charge Energy Ratio" (LER), which is the ratio of the charge energy in the second compression at 2 pounds per square inch (cycle C) to that of the first compression at 2 pounds per inch square (cycle B) during the sequence described above for a wet sample. The final wet volume measured at the end of the test (0.025 pounds per square inch) was called the "final volume" or the "FB" value. When the load is plotted as a function of thickness, the charge energy is the area under the curve as the sample goes from a discharged state to the peak load of that cycle. For a purely elastic material, the proportion of charge and jump energy back will be unity. Applicants have found that three measurements described above are relatively independent of the number of layers in the stack and serve as useful measurements of wet elasticity. Also referred to herein as the "compression ratio" which is defined as the ratio of wetted sample thickness to peak load in the first compression cycle at 2 pounds per square inch to the initial wetted thickness at 0.025 pounds per square inch.

In the performance of the previous measures of compressive elasticity, the samples must be conditioned for at least 24 hours under the TAPPI conditions (50% relative humidity, 73 degrees F). The specimens are cut with a matrix in 2.5 inch by 2.5 inch squares. The conditioned sample weight should be about 0.4 grams, if possible, and within the range of 0.25 to 0.6 grams for significant comparisons. The objective mass of 0.4 grams was achieved by using a stack of two or more sheets if the weight Leaf base is less than 65 grams per square meter. For example, for nominal sheets of 30 grams per square meter, a stack of three sheets will usually be close to a total mass of 0.4 grams.

Compression measurements are carried out when an Instron 4502 universal test machine interconnected with a personal computer 286 running the Instron software series XII (1989 edition) and version 2 apparatus. The aforementioned "standard 286 computer" has a processor 80286 with a clock speed of 12 MHz. The personal computer used was a Compaq DeskPro 286e with a 80287 math compressor and a VGA video adapter. A kN load cell with circular plates of 2.25 inches in diameter was used for sample compression. The lower plate had a ball bearing assembly to allow an exact alignment of the plates. The bottom plates are fixed in place under load (30-100 lbf) by the top plate to secure parallel surfaces. The top plate should also be fixed in place with the standard ring nut to eliminate play on the top plate when the load is applied.

After at least one hour of warm-up after startup, the instrument control panel is used to set the extensometer to zero distance while the plates are in contact (at a load of 10-30 pounds). With the upper plate freely suspended, the calibrated load cell is balanced to give a reading of zero. The extensiometer and the load cell should be checked periodically to avoid changing the baseline (fabric of the zero points). The measurements must be carried out in an environment of controlled humidity and temperature, according to the TAPPI specifications (50% ± 2% relative humidity and 73 degrees F). The top plate is then raised to a height of 0.2 inches and the control of the Instron is transferred to the computer.

Using the Instron series cyclic test program XII with a computer 286, an instrument sequence was established with 7 markers (discrete events) composed of three cyclic blocks (instruction sets) in the following order: Marker 1: Block 1 Marker 2: Block 2 Marker 3: Block 3 Marker 4: Block 2 Marker 5: Block 3 Marker 6: Block 1 Marker 7: Block 3 Block 1 instructs the crosshead to descend to 1.5 inches / minute until a load of 0.1 pounds is applied (the Instron setting is -0.1 pounds, since compression is defined as a negative force). The control is by displacement. When the target load is reached, the applied load is reduced to zero.

Block 2 directs the crosshead to vary from an applied load of 0.05 pounds to a peak of 8 pounds and then back to 0.05 pounds at a rate of 0.4 pounds / minute. Using the Instron program, the control mode is displacement, the limit type is load, the first level is less 0. 05 pounds, the second level is minus 8 pounds, the dwell time is 0 seconds, and the number of transitions is 2 (compression after relaxation); "no action" is specified for the end of the block.

Block 3 uses the displacement control and limit type to simply raise the crosshead to 0.2 inches at a rate of 4 inches / minute, with a dwell time of 0. Other Instron program placements are 0 on the first level , of 0.2 on the second level, of 1 transition and of "no action" at the end of the block.

When it was executed in the order given above, (markers 1-7), the Instron sequence compresses the sample to 0.025 pounds per square inch (0.1 lbf), relaxes, then compresses to 2 pounds per square inch (8 pounds), followed by compressing and cross-head elevation to 0.2 inches, then compresses the sample back to 2 pounds per square inch, relaxes, raises the crosshead to 0.2 inches, compresses back to 0.025 pounds per square inch (0.1 lbf) and then the crossed head is raised. The data entry should be carried out at intervals not greater than 0.02 inches or 0.4 pounds (whichever occurs first) for block 2 and for intervals not greater than 0.01 pounds per block 1. Preferably, the data entry is carried out out every 0.004 pounds in block 1 and every 0.05 pounds or 0.005 pounds (whichever comes first) in block 2.

The results of the series XII program are set to provide extension (thickness) at peak loads for markers 1, 2, 4 and 6 (at each 0.025 and 2.0 pounds per square inch peak load), the charge energy for the markers 2 and 4 (the two compressions at 2.0 pounds per square inch previously called cycles B and C, respectively). The ratio of energies of two loads (second cycle / first cycle), and the ratio of the final thickness to the initial thickness (ratio of thickness to at least the first compression of 0.025 pounds per square inch). The results of loading against thickness are plotted on the screen during the execution of blocks 1 and 2.

In carrying out a measurement, the dry sample and conditioned was focused on the lower plate and the test was started. After completing the sequence, the sample is immediately removed and applied to moisture (deionized water at 72-73 degrees F). Humidity is applied uniformly with a fine mist to achieve a moisture sample mass of approximately 2.0 times the initial sample mass (95-110% added moisture is applied, preferably 100% added wet based on conditioned sample mass; moisture level should give an absolute humidity ratio of about 1.1 g water / g fiber dried in the oven, with drying in the oven referring to drying for at least 30 minutes in an oven at 105 degrees centigrade). (For non-creped continuous dried materials of this invention, the moisture content should be within the range of 1.05 to 1.7 without significantly affecting the results). The spray should be applied evenly to the separate sheets (for stacks of more than one sheet) with the spray applied to both the front and the back of each sheet to ensure uniform moisture application. This can be achieved by using a conventional plastic spray bottle, with a container or other barrier blocking most of the spray, allowing only around the top 10-20% of the spray envelope - a fine spray - to approach the sample. The spray source should be at least 10 inches away from the sample during spray application. In general, care should be taken to ensure that the sample is uniformly wetted by a fine spray. The sample must be weighed several times during the moisture application process to reach the target moisture content. No more than 3 minutes must elapse between the completion of the compression test on the dry sample and the termination of the wet application. 45-60 seconds must be provided from the final application of the spray at the beginning of the subsequent compression test to provide time for internal transmission and dew absorption. Between three and four minutes will elapse between the completion of the dry compression sequence and the initiation of the wet compression sequence.

Once the desired mass range is reached, as indicated by a digital scale, the sample is centered on the bottom Instron plate and the test sequence is started. After the measurement, the sample was placed in an oven of 105 degrees Celsius for drying, and the dry weight of the oven will be recorded afterwards (the sample should be allowed to dry for 30-60 minutes after which the dry weight is measured).

Note that creep recovery between the two compression cycles can occur at 2 pounds per square inch so that the time between cycles can be significant. For the instrument placements used in these Instron tests, there is a period of 30 seconds (± 4 seconds) between the start of compression during the two cycles at 2 pounds per square inch. The beginning of compression is defined as the point at which the load cell reading exceeds 0.03 pounds. Similarly, there is an interval of 5-8 seconds between the start of compression in the first thickness measurement (ramp to 0.025 pounds per square inch) and the beginning of the compression cycle subsequent to 2 pounds per square inch. The interval between the start of the second compression cycle at 2 pounds per square inch and the start of compression for the final thickness measurement is approximately 20 seconds.

The utility of a fabric or an absorbent structure having a high moist compressed volume (WCB) value for a wet material which can maintain a high volume under compression can maintain a higher fluid capacity and is less likely to allow the fluid be squeezed out when compressed.

The high wet return ratio values are especially desirable because a wet material that skips back after compression can maintain a high pore volume for effective intake and distribution of insults or subsequent discharges of fluid, and such material may regain fluid during its expansion which may have been ejected during compression. In the diapers, for example, a wet region can be momentarily compressed by body movement or changes in body position. If the material is unable to regain its volume when the compressive force is released, its effectiveness for fluid handling is reduced.

High charge energy ratio values in a material are also useful, so that such material continues to resist compression (LER is based on a measurement of the energy required to compress a sample) at loads less than the peak load of 2 pounds per square inch, even if it has been heavily compressed once. The maintenance of such wet elastic properties is believed to contribute to the feel of the material when used in absorbent articles and can help to maintain the notch of the absorbent article against the wearer's body, in addition to the general advantages acquired when a structure It can maintain its pore volume when it is wet.

The hydrophobically treated absorbent fabrics of this invention and the inherently untreated hydrophilic base sheets useful for producing this invention may exhibit one or more of the above properties. More specifically, said absorbent fabrics and the base sheets can have a wet compressed volume of about 6 cubic centimeters per gram or more, more specifically about 7 cubic centimeters per gram or more. cubic centimeters per gram or even more, more specifically about 8 cubic centimeters per gram or more, and even more specifically from about 9 to about 13 cubic centimeters per gram. The compression ratio may be about 0.7 or less, more specifically about 0.6 or less, even more specifically about 0.5 or less, and even more specifically from 0.4 to about 0.7. Also, these may give a wetback jump ratio of about 0.6 or more, more specifically from about 0.7 or more, more specifically around 0.85 and even more specifically from about 0.8 to about 0.93. The charge energy ratio may be around 0.6 or more, more specifically from 0.7 or more, more specifically still from 0.8 or more, and more specifically from about 0.75 to about 0.9. The final volume may be about 8 cubic centimeters per gram or more or preferably about 12 cubic centimeters per gram or more.

The "permeability in plane". An important property of the porous medium particularly for the absorbent products is the permeability to the flow of the liquid. The complex interconnected trajectories between the solid particles and the boundaries of a porous medium provide routes for fluid flow which can offer significant flow resistance due to the narrowness of the channels and the tortuosity of trajectories.

For paper, permeability is commonly expressed in terms of gas flow rates through a sheet. This practice is useful for comparing similar sheets, but does not truly characterize the interaction of the fluid that flows with the porous structure and does not provide direct information about the flow in a wet sheet. The normal permeability engineering definition provides a more useful parameter, even when one that is less easily measured. The standard definition is based on Darcy's law (see FAL Dullien, Porous Medium: Fluid Transport and Pore Structure, academic press, New York, 1979), which for a one-dimensional flow, states that the velocity of the flow of fluid through a saturated porous medium is directly proportional to the pressure gradient: K? P V = μ L (i) where V is the surface velocity (flow rate divided by area), K is the permeability, μ is the viscosity of fluid, and? P is the pressure drop in the direction of flow through a distance L. The units of K are square meter. In equation (1), permeability is a parameter of empirical proportionality linking the velocity of fluid to the pressure drop and viscosity. For a homogeneous medium, K is not a function of? P, the sample length or viscosity, but is an intrinsic parameter that describes the resistance to medium flow. In a compressible medium, permeability will be a function of the degree of compression. The Darcian permeability is a fundamental parameter for processes that involve the flow of fluid in fibrous tissues.

The given permeability has units of area (square meter) and for simple uniform cylindrical pores it is proportional to the cross-sectional area of a single pore. However, the permeability of most real materials can not be predicted from an optical assessment of pore size. The permeability is determined not only by the pore size, but also by the pore orientation, the tortuosity, and the interconnectedness. Large pores in the body of an object may be inaccessible to fluid flow or accessible only through tiny pores that offer high resistance to flow. Even with a complete three-dimensional description of the pore space of a material through an X-ray tomography or other imaging technique, it is difficult to predict or calculate permeability. Permeability and pore size determinations are related but without different pieces of information about a material. For example, a metal sheet with discrete non-overlapping holes drilled in it may have very large pores (the holes) while still having a negligible plane permeability. Swiss cheese has very large pores but typically has negligible permeability in any direction unless it is thinly sliced so that the individual orifices can extend from one face to the other of the cheese sample.

Many permeability studies on paper have focused on the flow in the z-direction (normal to the plane of the leaf) which is of practical importance in wet pressing and other unit operations. However, paper is an anisotropic material (for example, see EL Back, "The Pore Anisotropy of Paper Products and Fiberboard Construction Cartons", Svensk Papperstidning, 69: 219 (1966)), meaning that The fluid flow properties are a function of the direction. In this case, the different directions of flow will appear to have different apparent permeabilities. The many possibilities of flow direction and pressure gradients in such a medium can be encompassed with a multidimensional form of Darcy's law, -K - P, V = (2) where v is the surface velocity vector (volumetric flow rate divided by the sectional area - transverse flow), μ is the viscosity of the fluid, K is a second order tensor and Vp is the pressure gradient. If a Cartesian coordinate system is chosen to correspond to the main flow directions of the pore media, then the permeability tensor becomes a diagonal matrix (see Jacob Bear, "Dynamics of Fluids in the Porous Medium", American Elsevier , New York, New York 1972, pages 136-151): where K ,, K- ,, and? they are the main permeability components in the x-, y- and z- directions, respectively. On paper, these directions will generally correspond to the transverse direction (taken here as y) and the direction of the machine (taken as x, the direction of permeability in the maximum plane) in the plane, and the transverse or thickness direction ( z). Thus the anisotropic permeability of typical machine-made paper can be characterized with three permeability parameters one for the machine direction, one for the transverse direction, andone for the z-direction. (In some cases, such as when there are unbalanced flows in the headbox of the paper machine, the direction of maximum permeability may be slightly outside the direction of the machine, the direction of permeability in the maximum plane and the orthogonal direction that one must be used for the addresses x- and y- respectively in that case). In the hand sheets, there may not be a preferential orientation direction for fibers lying in the plane, so that the permeability values in the x- and y- direction must be the same (in other words, such a sheet is isotropic in the plane).

Despite the past focus on permeability in the z-direction on paper, plane permeability (both K ,. and Ky are factors in plan) is important in a variety of applications, especially in absorbent articles. Body fluids or other liquids flowing into the absorbent article usually enter the article in a localized and narrow region. Efficient use of the absorbent medium requires that the incoming fluid be distributed laterally through the flow in plan in the absorbent article, otherwise the local capacity of the article to handle the incoming liquid can be overwhelmed resulting in runoff and poor utilization of the absorbent core. The ability of the fluid to flow in the plane of the article is a function of the driving force for fluid flow what which can be a combination of capillary transmission and hydraulic pressure from the fluid source in the ability of the porous medium to conduct the flow, which is largely described by the Darcian permeability of the material. Fluids or two-phase and non-Newtonian flow suspensions complicate physics, but the permeability in plane of the porous medium is a critical factor for the rapid plane distribution of liquid insults. Especially in the case of urine handling, where liquid flow rates may occur in excess of the capacity of the capillary forces, high in-plane permeability is necessary in the intake layer to allow the fluid to be distributed laterally. rather than draining.

Even though many past studies of liquid permeability on paper were focused exclusively to measure ^ for flow in the z-direction, more recently, methods for measuring plane permeability on a sheet of paper have been taught. J.D. Lindsay and P.H. Brady teach methods for permeability measurements in plane and in the Z direction of saturated paper in the work "Anisotropic Permeability Studies with Applications to Water Removal in Fibrous Fabrics: Part I", Tappi J., 76 (9): 119 -127 (1993) and "Anisotropic Permeability Studies with Applications for Water Removal in Fibrous Tissues: Part II", Tappi, J. 76 (11): 167-174 (1993). The methods related by K. L. Adams, B. Miller and L. Rebenfield and the work "Flow in Forced Plane of an Epoxy Resin in Fiber Networks", Engineering and Science of Polymer, 26 (20): 1434-1441 (1986); J.D. Lindsay and the work "Relative Flow Porosity in the Fibrous Environment: Measurements and Analysis, including Dispersion Effects", Tappi J., 77 (6): 225-269 (June 1994); J.D. Lindsay and J.R. Wallin, "Characterization of Flow in Paper Plane" forestry products symposium ALChE 1989 and 1990, Tappi Press, Atlanta, Georgia (1992) page 121; and D.H. Horseman, J.D. Lindsay and R.A. Stratton, "Using Edge Flow Tests to Examine the Permeability of Anisotropic Paper in Planes", Tappi J. 74 (4): 241 (1991).

The basic method used in most of these publications is the injection of fluid in the center of the paper disc that is constricted between two flat surfaces to force the flow of the fluid to be in the radical direction, proceeding from the injection point to the center from the disk to the outer edge of the disk. This is illustrated in Figure 9, which shows a sheet 41 in which a hole 42 has been punctured and in which the fluid is injected by means of an injection port of the same size as the punched hole. The fluid is forced to fluid to the outer radial edge 43. For a saturated sheet of liquid of a constant thickness subjected to a stable radial fluid flow in the manner described in the work of Lindsay et al., The equation relating to the average The permeability in plane to the fluid is: Kr = Kx_ Ky = Q lníEoíEi), 2 2pLp? P (4) where R0 is the paper disk radius 41, R1 is the radius of the central hole 42 in which the fluid is injected through an injection port; Lp is the thickness of the paper,? P is the constant pressure above the atmospheric pressure of the fluid which the fluid is injected into the disk (the measurement pressure in the injection pore, Q is the volumetric flow rate of the liquid and Kr is the permeability in plane, technically the average radial permeability defined as the average of two plane permeability components. The central inlet hole 42 was consistently 0.375 inch (3/8 inch) and was created using a paper punch tool The test apparatus for plane permeability measurements is shown in Figure 10 and in Figure 11, which is similar in principle to the apparatus shown by Lindsay and Brady, previously indicated: The tubes 45 connect water from the water reservoir to a perforated injection port in a one-inch Plexiglass 45 support plate. of thickness (the support plate is transparent to allow the vision of the moistened sample, especially in cases when an aqueous dye solution is injected into the sample. I would like to An angle of 45 ° below the support plate facilitates vision and photography. The water reservoir 51 provides a nearly constant hydraulic head 49 for fluid injection during the test. The volumetric flow rate is obtained by noting the change in the water reservoir mass as a function of time, and converting the mass flow rate of water to a volumetric flow rate. Deionized water with vacuum at room temperature is used. In using the apparatus, a paper disc 41, cut to be 5 inches in diameter and having a center hole diameter of 0.375 inches, was placed on the support plate 46 on the injection port 44 (0.375 inches of diameter too) and then saturated with water. The fluid injection pipe 45. The injection port 44 can be filled with water and efforts must be made to prevent air bubbles from being trapped in the sheet or in the injection area. To help eliminate air pockets, sample 41 should be gently folded in the center when placed on the wet support plate to initiate liquid contact in the center of the sample; the edges can then be gradually lowered to create a wedge-type movement of the liquid meniscus to remove air bubbles from under the sheet. Stacks of multiple strata of leaves can be handled in the same way, even though wetting the preliminary sample may be necessary to remove air bubbles from "strata". The objective of removing the air bubbles is to reduce the Blocking flow that can cause trapped air bubbles. Once the moistened sample is in place, a cylindrical metal plate 47, 5 inches in diameter, is gently lowered over the top of the sample to provide a constant compressive load and to provide a reference surface on its part. upper for the thickness measurement with displacement meters 48. Three displacement meters 48 are used, spaced approximately evenly around the edge of the upper part of the metal cylinder 47, they must measure the thickness by means of the sheet 41. The thickness of the sample is taken as the average of three displacement values in relation to a zero point when a sample is not present. A suitable thickness meter is the Mitutoyo indicator, model 543-525-1, with a 2-inch stroke (contact spindle displacement) and a precision of one micrometer. The thickness gauges are mounted rigidly in relation to the support plate. The contact spindles of the thickness gauges can be raised and lowered (without changing the position of the meter body) by using a cable to provide a clearance to move the metal plate over the sample. The small force applied by the thickness gauges 48 must be added to the weight of the metal plate 47 to obtain the total force applied to the sample 41; this force, when divided by the cross-sectional area of the sample and the plate, should be 0.81 pounds per square inch.

A 13-inch hydraulic head is used to eject the liquid flow. The head is the vertical distance 49 between the water line 50 of the supply tank 51 and the plane of the sample 41. This head was achieved by placing a water bottle 51, filled to a specified level 50, on a scale of mass 52 at a fixed height relative to the support plate 46 on which the sample rests. When the sample is placed on the support plate, the water tank is at such a height that the water level 50 in the tank is almost the same as (or slightly greater than) that of the support plate 46 on which it rests. the sample. When the sample has been moistened and placed under the compressive load on the metal plate, the water tank is then raised and placed on a mass balance 52 so that the water level is 13 inches above the plate of support. A timer is activated and the mass of the water tank is recorded at 20-second intervals and 30 seconds at least for 90 seconds. The thickness readings of the three gauges are also recorded regularly during the test to reduce entrainment, the saturated sample must be allowed to equilibrate under the compressive load for at least 30 seconds before the bottle is elevated and the forced flow begins through the sample.

The change in the water reservoir mass is as a function of time given the mass flow rate, which can be easily converted to a volumetric flow rate to be used in equation 4. The principles of normal engineering should be used to ensure that adequate units (preferably the SI units are used in the application of Equation 4).

In the performance of plane permeability measurements, it is important that the sample be compressed uniformly against the restrictor forces to avoid openings or large channels that could provide paths of least resistance for substantial liquid flow that could deviate or jump a lot of the same sample. Ideally, the liquid will flow through the sample, this can be determined by injecting the stained fluid during the sample and observing the shape of the stained region through the transparent support plate. The injected dye should be sprayed out evenly from the point of injection. In isotropic samples, the shape of the mobile dye region must be almost circular. In flat co-anisotropy materials due to fiber orientation or structural orientation on a small scale the shape of the dye region must be oval or elliptical, and almost symmetric around the injection point. A suitable dye for such purple Versatin II tests made by Milliken Chemical Corporation, (Inman, SC). This is a fugitive dye that is not absorbed on cellulose, allowing an easy visualization of the flow liquid through the fibrous medium.

As will be illustrated in the examples, the fabrics of the base sheets of this invention possess a very high permeability. Flat permeability can be about 0.1 x 10"10 square meters or more, more specifically May 0.3 x 10" 10 square meters or more, more specifically May 0.5 x 10"10 square meters or more, even more specifically from about 0.5 x 10"10 to about 8 x 10" 10 square meters or greater, and even more specifically from about 0.8 x 10"10 to about 5 x 10" 10 square meters.

Brief Description of the Drawings Figure 1 is a cross section of absorbent tissue comprising a contoured resilient base sheet having areas of hydrophobic material.

Figure 2 shows the absorbent fabric of Figure 1 in contact with an underlying absorbent fibrous layer.

Figure 3 shows the woven 3 exhibits the absorbent weave of Figure 1 attached to an inverted base sheet having a similar topography.

Figure 4 shows a suitable paper machine to produce the contoured elastic base sheet of the present invention shown in Figure 1.

Figure 5 shows a version of Figure 2 in which the lower regions of the base sheet are provided with openings.

Figure 6 exhibits a pattern of hydrophobic material printed on a hydrophilic base sheet.

Figure 7 shows a height profile and several lines of material to illustrate the definition of a material surface curve and the height PlO.

Figure 8 shows a CADEYES profile of sample 13 of the present invention.

Figure 9 shows the flow pattern on a paper disk during a plane permeability measurement (angle view).

Figure 10 is a side view of the plane permeability apparatus.

Figure 11 is a top view of the thickness and brass plate gauges in the apparatus of permeability in plane.

Figure 12 shows a gray scale height map of a section of the non-creped tissue base sheet showing relatively high regions such as the lower regions and light gray as dark gray or black.

Figure 13 is a schematic cross-sectional view in another embodiment of this invention.

Figure 14 is a schematic representation of an alternate embodiment in which the hydrophobic fibers are provided with a perforated fabric.

Figure 15 is a graph of rewet values and 95% confidence intervals for the sample of example 1.

Figure 16 is a table of physical property results for examples 3-6.

Figure 17 is a table of physical property results for examples 7-10.

Detailed Description of the Drawings Figure 1 shows a cross section of a contoured inherently hydrophilic base sheet 1, preferably a sheet of elastic cellulose tissue, on which a hydrophobic material 2 has been deposited on the uppermost regions 3 of the contoured base sheet to form a composite absorbent fabric. The upper side of the fabric having the hydrophobic material 2 can serve as the skin contact layer of an upper sheet or liner of an absorbent article. The hydrophobic material preferably resides only over the raised regions of the base sheet as shown, preferably penetrating no more than about 50% of the thickness of the base sheet, more specifically not more than about 20% of the thickness of the base sheet. the base sheet, and more preferably no more than about 10% of the thickness of the base sheet. For some products, it may be desirable for the hydrophobic material to be almost exclusively on the upper (outer) surface of the fibers on the upper surface of the base sheet, with very little penetration into the base sheet itself. Deposits of hydrophobic material generally have a thickness that rises at a distance above the underlying hydrophilic base sheet. In some embodiments, the distance above the underlying hydrophilic base sheet may be less than about 3 millimeters, less than 0.5 millimeters, less than 0.1 millimeter, 0.05 millimeters or less. between 0.05 and 0.5 millimeters. In some preferred embodiments, the thickness of the hydrophobic deposits relative to the local thickness of the hydrophilic base sheet may be less than 50%, alternatively less than about 20%, alternatively less than alternatively 10% or less. around 5% and 25%.

For a better performance in terms of liquid absorption, the density of the base sheet should preferably be essentially uniform across any characteristic cross-section of the base sheet, as is characteristic of non-creped air-dried tissues. other sheets of paper that have been dried by largely non-compressive media. Such sheet The base is relatively free of regions that have low permeability and low absorbent capacity and tend to be more elastic when wetted. The depressed regions 4 of the base sheet are essentially hydrophilic and can serve as the openings in a perforated film do by providing a pore space for sensing the liquids by providing regions in the middle of the hydrophobic material where the liquid can be transmitted. to an absorbent medium, the medium being the hydrophilic base sheet itself and optionally an underlying absorbent core preferably in contact with liquid communication with the composite fabric. The underlying absorbent core is preferably a fibrous mat such like a pulp-paper mat. One of such embodiment is shown in Figure 2 wherein the inherently hydrophilic base sheet 1 is in direct contact with a fibrous mat 5 for the improved transport of the liquid out of the composite fabric into the fibrous mat, the fibrous mat 5 can be provided by a heterogeneous structure having high density regions with small pores to provide a high capillary pressure to pull the liquid out of the composite tissue, while still having a significant amount of low density regions to provide adequate pore space to retain large amounts of fluid and to provide regions of high permeability. A heterogeneously identified fibrous mat 5 may have a relatively dense top layer in contact with the base sheet 1, or may have a pattern of densified regions imparted by etching or other means, preferably with at least some of the densified regions in contact direct with the lower hydrophilic parts 4 of the base sheet 1.

As shown in Figure 3, the inherently hydrophilic base sheet 1 may also be in contact 9 with a similar topography fabric having the depressions 7 to form a multi-stratum structure with a pore space of between significant stratum 8. Preferably, the fabric provides a combination of desired material properties: wet elasticity, to maintain the shape and volume when moistened; absorbency and good capillary structure to provide rapid fluid intake in the hydrophilic areas, softness on the upper surface on the side of the body for improved comfort; flexibility for comfort during use; and a three-dimensional contour to reduce the contact area against the body, thus resulting in less of a wet sensation when wet.

The inherently hydrophilic base sheet can be produced through a variety of methods. Preferably, the base sheet, before any calendering that may be desired, is characterized by a three dimensional low density structure created in a substantial part before the sheet reaches a solids level (dryness level) of about 60% higher and preferably about 70% higher. Suitable low density three-dimensional structures can be achieved through a variety of means known in the arts of papermaking, tissue production, non-woven fabric production, including but not limited to the use of high volume treated fibers. especially such as the chemically treated or crimped fibers as an additive in the supply, including the fibers taught by CC Van Haaften in the invention "Sanitary Towel with Cross-Linked Cellulose Layer", United States of America No. 3,339,550 issued on September 5, 1967, which is incorporated herein by reference; the means of mechanical debranching such as differential ("fast") speed transfer between fabrics or wires, hereinafter described; the mechanical deformation or "wet deformation" of the wet tissue, including the methods taught by M.A. Hermans et al., In U.S. Patent No. 5,492,598, "Method for Increasing the Internal Volume of Dried Tissue Continuously" issued February 20, 1996, incorporated herein by reference and M.A. Hermans et al., In U.S. Patent No. 5,411,636, "Method for Increasing the Internal Volume of Wet Pressed Tissue," issued May 2, 1995, incorporated herein by reference; molding the fiber into a three dimensional wire or fabric such as the fabrics described by Chio et al. in U.S. Patent No. 5,429,686"Soft Tissue Apparatus" issued July 4, 1995, which is incorporated herein by reference including the differential velocity transfer on or from said wire or three-dimensional fabric; the wet engraving of the leaf; hydroentanglement of fibers; wet creping; and the optional use of chemical disunsing agents. The inherently hydrophilic base sheets can also be produced from synthetic fiber and pulp composites, with an embodiment described in the commonly owned United States of America patent number 5,389,202, "Processor for Making a High-Woven Non-Woven Composite Fabric". Pulp Content "granted on February 14, 1995 to Cherie H. Everhart and others, incorporated here for reference.

Air-laid blends of cellulosic and synthetic fibers are within the scope of the present invention. Pulp fibers for air placement can be prepared by pulping, such as by a hammer mill, or other means known in the art. Methods for forming materials placed by air are well known in the art, including, for example, the methods described by Dunning and Day in U.S. Patent No. 3,976,734 issued August 24, 1976 and in U.S. Patent No. 5,156,902 issued October 20, 1992 to Pieper and others, both of which are incorporated herein by reference. Papermaking fibers suitable for air placement may include hardwood or softwood, low or high performance fibers, and chemically treated fibers such as merserized pulps, chemically bound or crosslinked fibers, sulfonated fibers. , and similar. Useful fiber preparation methods include those of Hermans and others described in U.S. Patent No. 5,501,768 issued March 26, 1996 and U.S. Patent No. 5,348,620 issued. on September 20, 1994, both of which are incorporated herein by reference. Fiber softening methods known in the art can also be employed, including compounds described by Smith et al. in U.S. Patent No. 5,552,020 issued September 3, 1996, and incorporated herein by reference. The pulp fibers can be carried in air or in steam and combined or intermixed with the newly formed hot synthetic fibers from a meltblown or spinneled process, or the pulp fibers can be mixed with a stream of cut synthetic fibers and relatively short (preferably less than 22 millimeters in length) carried in air. The binding agents and adhesives can be used to impart stability and wet strength to the structure placed by air, or the heat can be applied to partially melt some of the synthetic fibers to provide the bond. One embodiment comprises blends of papermaking fibers and meltblown polymers known as "coform" as taught in U.S. Patent No. 4,100,324 issued to Anderson et al .; U.S. Patent No. 4,879,170 issued to Radwanski et al .; and U.S. Patent No. 4,931,355 issued to Radwanski and others, all incorporated herein by reference. For the purposes of this invention, steps must be taken to impart the proper texture to the fabric. Such steps may include forming on a grid having a high and low permeability pattern to produce a fabric of thickness and basis weight with pattern, knit bonding, pattern bonding, engraving, pulling tissue regions in the z direction for interrupting the surface in a predetermined pattern, joining ultrasonic pattern, interrupting tissue with hydraulic fluid jets and others. Desirably, inherently hydrophobic synthetic fibers can be treated to increase wettability with respect to water, urine or menstrual fluids, using methods such as co-surfactant coating, supercritical fluid deposition of surfactants or other surfactants on the fiber surface, the protein or amphiphilic protein deposit, corona discharge treatment, ozonation, coating with hydrophilic matter, and the like. When the synthetic fibers are used in the production of the base sheet, they may constitute 70% or less by weight of the base sheet, preferably 40% or less, more preferably 20% or less, more preferably even 10% or less, and more preferably between about 1% and about 10%. Alternatively, the fabric may comprise between about 1% and about 10% synthetic fibers. Alternatively, the fabric may comprise between about 1% and 50% synthetic polymer fibers. Lower synthetic fiber content is generally desirable to reduce cost, even though other factors may be more important in determining the optimal fiber blend for a specific product. Other materials suitable for incorporation into the absorbent articles of the present invention include the soft tissues of Tanzer and others of U.S. Patent No. 5,562,645. granted on October 8, 1996, and incorporated herein by reference.

In a preferred embodiment, the base sheet is a wet laid tissue produced without creping and drying through non-compressive means. The techniques for producing such sheets are described by SJ Sudall and SA Engel in U.S. Patent No. 5,399,412, "Wipes and Towels Continuously Dried and Non-Creped Having High Resistance and Absorbency", granted March 21, 1995; R. F. Cook and D. S. Westbrook in U.S. Patent No. 5,048,589, "Towel Cleaner or Non-Creased Hands Towel", issued September 17, 1991; and J. S. Rugowski et al., "Paper Making Machine for Making Continuously Dried Non-Creped Tissue Sheets", U.S. Patent No. 5,591,309, issued January 7, 1997, all incorporated herein by reference.

A preferred method for producing the base sheet for the present invention is shown in Figure 4. For simplicity, the various tensioning rolls schematically used to define the various fabric runs are shown but not numbered. It will be appreciated that the variations of the apparatus and the method illustrated in Figure 4 can be made without departing from the scope of the invention. A trainer of twin wire having a head box for making a paper in layers 10 which injects or deposits a stream 11 of an aqueous suspension of fibers for making paper on a forming fabric 13 which serves to hold and carry the freshly formed wet fabric towards down in the process when the fabric is partially drained to a consistency of around 10% by dry weight. An additional drainage of the wet fabric can be carried out, such as by suction with vacuum, while the wet fabric is held by the forming fabric. The head box 10 can be a conventional headbox or it can be a layered headbox capable of producing a multiple layer unitary fabric. For example, it may be desirable to provide straight or relatively short fibers in one layer of the base sheet to give a layer with a high capillary pressure, while the other layer comprises relatively longer, bulkier or more crimped fibers for a high layer. permeability and a high absorbent capacity and a high pore volume. It may also be desirable to apply different chemical agents to separate the layers of a single fabric to optimize the dry and wet strength, the pore space, the wetting angle, the appearance or other properties of a fabric. Multiple head boxes can also be used to create a layered structure as is known in the art.

The wet fabric is transferred from the forming fabric to a transfer cloth 17 by moving preferably at a slower speed than that of the afferent forming fabric to impart an increased stretch to the fabric. This was commonly referred to as a "quick" transfer. Useful means of carrying out the rapid transfer are taught in U.S. Patent No. 5,667,636 issued March 4, 1997 to S. A. Engel et al., Incorporated herein by reference. The relative speed difference between the two fabrics can be from 0-80 percent, preferably more than 10%, more preferably from about 10 to 60 percent, and more preferably from about 10 to 40 percent . The transfer is preferably carried out with the help of a vacuum shoe 18 so that the forming fabric and the transfer fabric simultaneously converge and diverge at the leading edge of the slot with vacuum.

The fabric is then transferred from the transfer fabric to the continuous drying fabric 19 with the aid of a vacuum transfer roller 20 or a vacuum transfer shoe, optionally again using a fixed separation transfer as previously described . The continuous drying fabric can be moved around the same speed or at a different speed in relation to the transfer fabric. If desired, the continuous drying fabric can be run at a slower speed to further increase the stretch. The transfer is preferably carried out with the aid of vacuum to ensure the deformation of the sheet to conform to the drying fabric continuously, thus giving the desired volume and appearance. Suitable continuous drying fabrics are described in U.S. Patent No. 5,429,686 issued to Kai Chiu et al., Previously incorporated by reference.

In a preferred embodiment, the fabric comprises a sculpture layer on lay or integrally connected to a load bearing layer, said sculpture layer comprises raised and elongated elements having an aspect ratio of at least 4, preferably of at least 6, more preferably at least 10, more preferably at least 20, and more preferably between about 8 and about 50. The fabric may be woven or non-woven. In one embodiment, the fabric is a woven fabric wherein the load-bearing layer comprises warps in the direction of the embossed machine and ducts in the transverse direction and the sculpture layer comprises additional warps or ducts interwoven into the weft of the fabric. the load-bearing layer, wherein the highest knuckles of the sculpture layer may be greater than the highest knuckles of the load-bearing layer by about 0.1 millimeters or more, preferably 0.2 millimeters or more, more preferably 0.5 millimeters or more, and more preferably between about 0.4 millimeters and about 2 millimeters. For the purposes of imparting a stretch in the improved cross direction of the base sheet, the highlighted and elongated elements of the sculpture layer should preferably be oriented in the machine direction.

The number of raised and elongated elements per square inch of the fabric should be between about 5 and about 300, more preferably between about 10 to about 100. The resultant continuous dried base sheet will have elevated regions preferably comprising between about 5 and about 300 protrusions per square inch having a height relative to the plane of the base sheet, as measured in the uncalendered state and in the uncreped state of about 0.1 millimeters or more, preferably from 0.2 millimeters or more, more preferably about 0.3 millimeters or more, and more preferably from about 0.25 to about 0.6 millimeters. When the base sheet structure comprises a relatively planar part with both protuberances and depressions "departing therefrom, the relatively planar part is taken as the plane of the base sheet. In some structures, a base sheet plane may not be well defined. In such cases, the protrusion height can be measured in relation to the depth characteristic of the deepest depressions. In any case, the protrusion height in relation to the depth characteristic of the deepest depressions, as measured in the uncalendered state and in the non-creped state, may be about 0.1 millimeter or greater, preferably 0.3 millimeter or greater, more preferably about 0.4 millimeter or greater, more preferably still about 0.5 millimeters or greater, and more preferably from about 0.4 to about 1.2 millimeters. In a specific embodiment, the raised regions of the base sheet correspond to the knuckles in the machine direction raised from a sculpture layer of a three-dimensional continuous dried fabric used to produce a non-creped continuous dried fabric. The fabrics formed in this manner have unusually high values of transverse direction stretch before failure, as measured in standard stress tests of 6% or more, preferably 9% or more, and more preferably 12% or more due to the topography in the high transverse direction imparted by the elements in the direction of the machine raised on a drying cloth continuously. The stretch in the machine direction can be increased by the rapid transfer and can be at least as large as the stretch in the transverse direction and preferably at least 10% and more preferably at least 14% .The level of vacuum used for the transfers of weave can be from around 3 to around 15 inches of mercury (from 75 to about 380 millimeters of mercury), preferably about 5 inches (.25 millimeters) of mercury. The vacuum shoe (negative pressure) can be supplemented or replaced by the use of positive pressure from the opposite side of the fabric to blow the fabric onto the next fabric in addition to or as a replacement to suck it onto the next fabric with vacuum. A vacuum roller or roller can also be used to replace the vacuum shoe or shoes.

While held by the continuous drying fabric, the fabric is finally dried to a consistency of about 94 percent or greater by the continuous dryer 21 and then transferred to a carrier fabric 22. The dry base sheet 23 is conveyed to the spool 24 using the carrier fabric 22 and an optional carrier fabric 25. An optional pressurized tumbling roller 26 can be used to facilitate the transfer of the fabric from the carrier fabric 22 to the fabric 25. The carrier fabrics suitable for this purpose are Albany International 84M or 94M and Asten 959 or 937, all of which are relatively smooth fabrics that have a fine pattern. Even when not shown, the reel calendering or subsequent off-line calendering can be used to improve the smoothness and smoothness of the base sheet.

The base sheet can be cut into slits, perforated or provided with openings formed by cutting, stamping or perforating action of fine water jets. Such perforations or openings can assist in the transfer of the fluid to an underlying absorbent core. Preferably, the openings are provided near or within the depressed areas of the contoured base sheet that serves as hydrophilic zones. Figure 5 shows a cross-section of such incorporation in which the base sheet 1 has been provided with the perforations 27 in the low hydrophilic regions.

The co-perforation of the non-woven material with the underlying base sheet, wherein the non-woven fabric and the base sheet are simultaneously perforated as with a bolt perforation of a two-layer structure, is possible within the scope of the present invention. invention but not preferred. The co-perforation tends to place hydrophobic matter of the non-woven fabric on the hydrophilic material of the base sheets in the openings, so that the fluid entering the perforation can find a hydrophobic barrier between it and the base sheet. It is desired that the fluid entering the openings be able to flow into the base sheet. The openings in the base sheet can improve subsequent transport into the underlying core, but the hydrophobic properties of the base sheet must positively contribute to the fluid handling handling performance of the composite roofing material.

Figure 7 to Figure 11 have been previously discussed.

Figure 12 shows a representative portion of a gray scale height map of a base sheet structure of a potential value in the present invention, acquired by the moire CADEYES interferometer (Medar, Inc., of Farmington Hills, Michigan) having a field of view of 38 millimeters. The tissue is a structure dried through non-creped air that has a surface depth of about 0.3 millimeters. Preferably, the base sheet is textured or molded before complete drying to impart an overall surface depth in the dried structure of about 0.1 millimeter or greater, more preferably about 0.3 millimeter or greater, or even more preferably around of 0.4 millimeters or greater, even more preferably of about 0.5 millimeters or greater, and more preferably from about 0.4 to about 0.8 millimeters. In another preferred embodiment, the base sheet further contains at least 10% by weight of high performance or other elastic wet pulp fibers and an effective amount of moisture resistant resin so that the wet tension ratio : dry is at least around 0.1. The uppermost elevated regions of the base sheet preferably offer relatively flat and flat plateaus so as to be placed against the skin with a relatively small sense of abrasion or roughness The hydrophobic material 2 on the base sheet as shown in Figure 1 is preferably deposited on relatively high regions of the fabric, such as the white or light gray regions on the height map of Figure 12, in order to place the regions hydrophobic in contact with the user's body when the fabric is used as a top sheet in an absorbent article. The hydrophobic material is preferably deposited on a sufficiently large part of the base sheet to make a distinct improvement in the sensation of dryness while still allowing liquid transport by transmission in the z-direction (normal thickness direction to the plane of the tissue) in multiple hydrophilic regions. Proper application of the hydrophobic material to a fraction of the upper surface of the hydrophilic base sheet will generally result in a decrease in the rewet value relative to the untreated base sheet (meaning an improvement in dry feel) of at least about 10%, more specifically at least about 20%, more specifically at least about 30%, even more specifically at least about around 40%, and more specifically from around 10% to around 60%. The resulting rewet value is preferably less than about 1 gram, more specifically less than about 0.65 grams, more specifically less than about 0.5 grams, even more specifically less than about 0.4 grams, and more specifically less than about 0.3 grams. The resulting normalized rewet value is preferably less than about 1, more specifically less than about 0.7, more specifically less than about 0.5, even more specifically less than about 0.4, and more specifically less than about of 0.3. In one embodiment, there is essentially no hydrophobic material present below 50% of the line material of a characteristic profile of the fabric, or below the median plane of a typical cross section of a contoured fabric.

In one embodiment, the hydrophobic material is applied in a manner designed to limit the lateral (in plane) transmission of the liquids to prevent runoff or filtering from the edges of an absorbent article while also improving the feeling of dryness. The production of this incorporation usually requires that the hydrophobic material or materials be added to the upper surface of the hydrophilic base sheet in two ways so that some of the hydrophobic material essentially penetrates the base sheet to establish a barrier region for the hydrophobic material. inhibit plane transmission, while the rest of the hydrophobic material is applied more lightly to apply substantial penetration into the base sheet. The regions Barrier can also use hydrophobic material for filling in the depressions of the fabric to prevent the flow of liquid along the channels or surface pores. The different hydrophobic materials and the application means can be used for the two or more regions of different penetration depth or different basis weight of application. One approach suitable for use in absorbent articles such as feminine pads or incontinence pads is to apply longitudinal bands of a hydrophobic material in liquid form, such as a melted wax or a polymeric compound, applied sufficiently in heavy form to permeate inside the base sheet by a significant part of the thickness of the base sheet, with said bands being near the edges of the absorbent article to limit the filtering from the edge. The remaining part of the base sheet can be treated with hydrophobic material applied more superficially to be less penetrating.

Suitable hydrophobic materials can comprise compounds which are solid or highly viscous at room temperature but can be made liquid or significantly less viscous at elevated temperature, allowing the application of the liquid at elevated temperature by etching, spraying, brush application, or other means, from which the liquid solidifies, gels or becomes essentially immobile at room temperature or at room temperature. body temperature. The hydrophobic agent can also be dissolved, dispersed or emulsified in a liquid carrier, such as water, and applied to the fabric by such means as coating, spraying, printing, after which part of the liquid carrier is removed by evaporation, absorption or other means for leaving a coating or hydrophobic impregnation on the fabric. The hydrophobic agent may also be composed of solid particles such as PTFE, polyolefins, or other polymers that have been milled and formulated into viscous fat or paste. Additionally, the hydrophobic material may be in solid form, such as fibers or particles that are adhesively bonded to the base sheet or bonded by entanglement, hydroentanglement, electrostatic attraction and others.

Suitable hydrophobic materials include silicone compounds, fluorocarbons, waxes, PTFE, wax emulsions, polyurethane emulsions, fats and fatty acid derivatives, polyolefins, nylon, polyesters, glycerides, and the like, as well as mixtures thereof. Various suitable materials containing solidified mixtures of waxes and oils are disclosed in the commonly owned US Patent No. 5,601,871, "Tissue Dried Continuously, Non-Creped, Treated and Mild" granted on February 11, 1997 to D. Krzysik and others, incorporated here by reference. Compounds containing oil, wax and optionally fatty alcohols are described herein, said compositions having melted points of between about 30 degrees Celsius to around 70 degrees Celsius. When they are distributed relatively uniformly over an uncreped tissue, said compositions significantly reduce liquid intake rates and reduce friction against the skin. It is believed that the hydrophobic compositions described by Krzysik and others can also be advantageously used in the present invention through a macroscopically non-uniform application of said compositions to a part of the higher regions of a hydrophilic, elastic and three-dimensional base sheet in Such a way as to avoid a significant reduction of liquid intake rates.

As described by Krzysik et al., Suitable oils include, but are not limited to the following classes of oils: petroleum or mineral oils, such as mineral oil and petrolatum; animal oils, such as mink oil and lanolin oil; plant oils, such as aloe extract, sunflower oil and avocado oil; silicone oils, such as dimethicone and alkyl methyl silicones. Suitable waxes include, but are not limited to the following classes: natural waxes, such as beeswax and carnauba wax; petroleum waxes, such as paraffin wax and ceresin; silicone waxes, such as acyl methyl siloxanes, or synthetic waxes, such as synthetic beeswax and synthetic sperm wax.

Useful silicone compounds and application methods are know in the art, including those of Kasprzak in the patent of the United States of America number 5,302,382 granted on April 12, 1994 and Kaun in the United States patent of America number 5,591,306 granted on January 7, 1997, both of which are incorporated herein by reference.

The amount of fatty alcohol, if present, in the Krzysik and other compositions can include that having a carbon chain length of C14-C30 including cetyl alcohol, stearyl alcohol, behenyl alcohol, dodecyl alcohol.

For some embodiments of the present invention, it is desired that the hydrophobic material have a melting point well above typical body temperatures since the absorbent articles containing the fabric of the present invention can be used against the low body. hot conditions, and any melting of the hydrophobic material can interfere with the performance of the absorbent article and eliminate the benefit of a dry feeling. For such articles containing Krzysik's other compositions and other compositions, said compositions should have a melting point well above about 35 degrees centigrade, specifically about 40 degrees centigrade, more specifically above about 45 degrees centigrade. and even more specifically above 50 degrees centigrade Other suitable hydrophobic compositions comprise up to 30 percent by weight of oil and from about 50 to about 100 percent by weight of wax, said compositions have a melting point of from about 40 degrees centigrade to about 200 degrees centigrade, more specifically from 70 degrees centigrade to around 170 degrees centigrade, more specifically above 75 degrees centigrade and more specifically still from around 85 degrees centigrade to 140 degrees centigrade. For the purposes given here, the "melting point" is the temperature at which most of the melting occurs, recognizing that melting actually occurs over a range of temperatures. Hydrophobic materials can also be used which do not melt or which degrade or decompose before or during melting.

Examples of water repellent agents which are potentially useful in the present invention include polyurethane emulsions such as Aerotex 96B from American Cyanamid; fluorochemical agents such as FC 838, FC 826 and the SCOTCHGARD compounds sold by Minnesota Mining and Manufacturing and Milease F-14 and Milease F-31X, sold by ICI. High molecular weight cationic fluorocarbons which can be formed in aqueous emulsions are also desired for ease of application and handling. An example of a potentially useful wax emulsion is Phobotex, sold by Ciba. A variety of other water repellent materials which may be applied to paper fabrics is reviewed disclosed in United States Patent No. 5,491,190 issued February 13, 1996 to Paul E. Sandvick Calvin J. Verbrugge, incorporated here by reference. Sandvic and Verbrugge focus primarily on the use of mixtures of fatty acids and polymers for paper sheets that can be reduced to pulp. Various wax and polymer compositions of a potential value for the present invention are disclosed in U.S. Patent Nos. 3,629,117 issued to Kremer et al .; 3,417,040 granted to Kremer; 3,287.14 issued to Dooley and others; 3,165,485 issued to Ilnyckyj and others; and 2,391,621 issued to Powell and others, all of which are incorporated herein by reference. Mixtures of hydrophobic latte and wax may also be used, including those taught in US Pat. No. 4,117,199 issued to Gotoh et al., Incorporated herein by reference. British Patent No. 1,593,331 issued Vase teaches a method for treating paper and board to make it water resistant by coating them with an aqueous latex coating composition. The lather coating composition is an acrylic polymer and a metal stearate or wax where the wax is at least 20% by weight of the total acrylic polymer and the metal stearate present. The meta stearate it is preferably calcium stearate. Latex emulsions, latex foams, and water absorbing polymers can be used, including those described in U.S. Patent No. 5,011,864 issued April 30, 1991 to Nielsen and Kim., incorporated herein by reference, which also describe combinations containing chitosan. Potentially useful latexes also include those described by Stanislawczyk in U.S. Patent No. 4,929,495 and anionic latex compounds are disclosed in U.S. Patent No. 4,445,970 issued May 1, 1984, both of which are incorporated herein by reference. After application, the coating is dried or cured on the paper. For the present invention, the composition must be applied non-uniformly to the upper surface of a base sheet.

Other examples of aqueous emulsions and emulsifiable compositions for similar paper coating are found in US Pat. Nos. 3,020,178 issued to Sweeney et al. And 3,520,842 issued to Crean (aqueous mixtures of petroleum wax; polymeric olefin and a fatty acid are added to the water containing an amine soap-forming agent such as an alkanolamine, followed by agitation and homogenization to form an aqueous emulsion coating composition). Hydrophobic matter may also comprise formulas intended to promote well-being of skin and comfort. For example, the hydrophobic material may include a hydrophobic base such as a mineral oil, waxes, petrolatum, cocoa butter, and the like, combined with effective amounts of skin care additives or pharmaceutical agents such as antibiotics and / or agents. antibacterials, antifungal agents, vitamin E (alpha tocopherol), lanolin, silícone compounds suitable for skin care, cortisone, zinc oxide, caustic soda, corn silk derivatives, avocado oil, emu oil, other oils natural plants and animals, and the like.

The hydrophobic material can also be applied in a fibrous or particulate form and attached to the base sheet through thermal fusion, chemical bonding through the use of a binder or adhesive, preferably a water-repellent, entangled binder (resulting of a high speed impact against a porous tissue), electrostatic bonding and the like. In a preferred embodiment, the hydrophobic material, whether applied as fibers, as particles or as a liquid or solution, can be deposited contiguously to form an interconnected network, such as the network of lines shown in Figure 6, in which case the hydrophilic regions are isolated from each other. In addition to the previously described materials, useful particulate hydrophobic agents include talcum powder and lycopodium powder.

Preferably, the hydrophobic material is applied to the desired regions with a local dry basis weight averaged in the range of from about 0.5 to about 50 grams per square meter, more specifically in the range of from about 1 to about 10 grams per square meter, more specifically around 5 grams per square meter or less, and more specifically around 3 grams per square meter or less. The hydrophobic material preferably comprises about 30% or less of the total mass of the dry absorbent fabric, more specifically about 20% or less, more specifically about 10% or less, and more specifically from about 1% to about 15% of the total mass of the dry absorbent fabric. The basis weight of the underlying base sheet can be from about 10 to about 200 grams per square meter, more specifically from about 15 to about 70 grams per square meter, and more specifically from about 15 to around 40 grams per square meter. For multi-stratum tissue structures, it is preferred that the basis weight be less than about 40 grams per square meter and more specifically less than about 30 grams per square meter.

In addition to the hydrophobic material, other agents can be suitably added to the base sheet according to this invention, including the superabsorbent particles or fibers. The superabsorbent material can be deposited or held in the depressed regions of the upper surface of the base sheet, or it can preferably be incorporated within the fibrous structure of the base sheet, attached to the lower surface of the base sheet, or incorporated between the base sheet and a bonded absorbent core. Other chemical agents can be added to any surface or both surfaces, or can be dispersed through the base sheet, applied to the inner or outer plates of the base sheet, or applied to selected surface regions of the base sheet, including application in a regular pattern such as gravure printing . Such chemical agents include emollients, lotions, chemical softeners, opacifiers, optical brighteners, moisture resistance agents, quaternary ammonium salts, proteins, cross-linking agents, virucides, bactericides, perfumes, dyes, chemical debonders, plasticizers for fibers of high performance, zeolites or other agents for odor control and the like. Chitosan and related derivatives can be incorporated into the articles of the present invention for their antibacterial benefits and other health benefits.; Triclosan and other antibacterial agents can similarly be incorporated.

Various mechanical and physical treatments can be applied to the base sheet before or after the addition of the hydrophobic material to improve the mechanical properties, the softness, or the functionality of the fabric. Such treatments include brushing, differential speed transfer between webs or fabrics, penetration by means of high velocity air jets, perforation, hydroentanglement, calendering, soft pressure point calendering, gradient calendering. thermal, corona discharge treatment, electret formation, microtunsion, dry creping, etching, slit cutting, and perforation. Preferably, the base sheet is not co-perforated with the top sheet.

Also within the scope of the present invention are the absorbent fabrics in which both sides of the fabric have been treated with a hydrophobic material. Such incorporation may be useful for absorbent towels and other materials where absorption may occur on any surface. In that case, it is preferred that the hydrophobic material is placed over most of the raised regions of both surfaces, the elevated regions being the higher regions when the respective surface faces upwards. Since the depressions on the upper surface will generally correspond to the raised regions on the lower surface when the lower surface faces upwards, especially when the fabric has an essentially uniform thickness through its cross-section, the material Hydrophobic on a surface will generally not be superimposed directly on another hydrophobic material on the other surface but the hydrophobic regions on the two surfaces will tend to be in a staggered relation to each other. The type of hydrophobic material, its method of application, and the amount applied may differ on both sides. Similarly, multiple applications of different hydrophobic materials can be carried out on a single surface to achieve the desired properties or desired visual appearance, including the use of multicolored fiber patches, colored adhesives and the like.

The scope of the present invention also includes multi-layered and laminated base sheet structures with one or more layers with the dual zoned adsorbed fabrics described above. For example, the absorbent core of traditional lint pulp used in many absorbent articles can be replaced by a series of elastic base sheet layers, such as the base sheets dried through non-creped elastic and wet air described in the Examples 7-10 below, and a dual zoned adsorbed fabric containing hydrophobic material can be placed in a superimposed relationship on said series of elastic base sheet layers. All or some of the multiple layers may also be provided with openings, slits, engravings, and the like. Multiple strata can be fixedly fastened one another through adhesives, sewing with thread, becoming entangled with perforation or fluid jets, engraving or the like.

An excellent hand towel can be made by taking advantage of the unusually high wet elasticity of non-compressed and non-creped base sheets, especially those containing elastic fibers such as high performance fibers and containing wet strength agents. The fiber-to-fiber bonds of such sheets comprise hydrogen and covalent bonds which are formed during non-compressive drying while the sheet is in a three-dimensional molded structure. While calendering can flatten such a base sheet, many of the joints are not disturbed. When the base sheet is subsequently moistened, the inflatable fibers can be relieved from the tension imparted by calendering and can return to the structure achieved during drying. In a sense, the joints have been fixed in a memory of the base sheet structure achieved during the drying and setting of the wet strength resins. It is therefore possible to prepare a flat and calendered base sheet which can be returned to a more bulky three-dimensional state with wetting, as described in commonly owned co-pending application serial number 60 / 013,308 filed on March 8, 1996 to D Hollenberg et al., Incorporated here by reference. Such "thin material when dry, thick when wet" can be advantageously used in the present invention. By adding hydrophobic material to the raised regions of a base sheet and then calendering the base sheet, or alternatively, by adding hydrophobic material to the previously high points after calendering, a relatively thin, flat absorbent fabric is produced which It has hydrophilic and hydrophobic regions in essentially the same plane. That structure can absorb fluids well with contact because the hydrophilic regions are in contact with the fluid. However, after moistening, the absorbent tissue expands so that the hydrophilic regions of moist sensation are no longer in direct contact with the skin while the hydrophobic regions of dry sensation rise to make contact with the skin. Such an absorbent fabric desirably has an overall surface depth of about 0.2 millimeters or less while it is dry and about 0.3 millimeters or greater when moistened to a moisture content of 100%. Alternatively, the calendered absorbent fabric may have an overall surface depth of about 0.3 millimeters or less while it is dry and about 0.4 millimeters or greater, more specifically about 0.5 millimeters or greater when it is moistened to a moisture content of 100%.

Additions with Hydrophobic Fibers Figure 13 shows a form of a preferred set of embodiments wherein the hydrophobic material comprises groups or bundles of thin polyolefin fibers 50 or other hydrophobic fibers in order to provide a smooth fabric type feel. The fibers may comprise a variety of lengths and types of fiber 50a and 50b, or may be primarily short fibers 50c with a fiber length smaller than the characteristic length of the raised regions of the base sheet or may be primarily long fibers 50c with a length close to or greater than the characteristic length of the elevated regions of the base sheet. In one embodiment, the bundles can be patches of short synthetic fibers preferably attached to the raised regions of the upper surface of the base sheet so that less than 80%, preferably less than 50%, and more preferably less than about 25%. % of the surface area of said base sheet is covered by the synthetic fibers attached. Such fibers may be applied by adhesives, thermal bonding, ultrasonic bonding, electrostatic attraction, perforation, entanglement, hydroentanglement, or through the use of binder adhesives, including water-repellent binders. The binder adhesives can include hydrophilic agents such as polyvinyl alcohol, starch, cationic latexes, proteins, and the like. Provided that the hydrophobic effect of the attached fibers is not destroyed or severely reduced by the use of such adhesives. To ensure hydrophobic activity, water-repellent binders may be desirable, including materials such as polybutyl acrylate, styrene-acrylic copolymer, acrylic vinyl chloride copolymer, acrylic acid-ethylene copolymer, copolymer vinyl acetate-ethylene, the vinyl chloride-ethylene copolymer, the acrylic copolymer latex, the butarien-styrene latex and the vinyl chloride latex. Suitable repellent binders which can be used are Geon 580X83 and Geon 580X119, sold by Goodrich (consisting of vinyl chloride latex); Emulsion E 1497, and Emulsion E 1847, sold by Rohm & Hass (consisting of an acrylic emulsion); and Rhoplex NW-1285 sold by Rohm & Haas (consisting of an acrylic emulsion); Airflex 120 and Airflex EVLC 453, sold by Air Products (consisting of ethylene vinyl chloride emulsions); Nacrilico 78-3990, sold by National Starch (consisting of an acrylic emulsion) and Primacor, sold by Dow Chemical (consisting of an acrylic acid-ethylene copolymer).

As shown in Figure 3, a densified absorbent material 51 is preferably in contact with the underside of the hydrophilic base sheet 1 where the densified absorbent material has a pore size smaller than the characteristic pore size of the sheet base 1 or a density greater than the density of the base sheet 1 and preferably has a density of about 0.1 g / cc less, and more preferably of about 0.2 g / cc or less. The densified absorbent material may be an air-laid fabric or a layer of densified fluff pulp or other layers of tissue cellulose. Preferably, the densified absorbent material is stabilized to prevent excessive expansion or loss of absorbent capacity with swelling. Stabilization can be achieved through the addition of thermosetting fibers or particles followed by heat treatment, by the addition of crosslinking agents followed by a heat treatment or by adequate curing, by the addition of adhesives in the fabric or other means known in the art. When the fluid enters the base sheet 1, the capillary forces can then transmit the fluid into the absorbent material. If the material is stabilized, it will be less likely to lose its capillarity with the wetting but it can continue transmitting and retaining the fluids effectively.

The hydrophobic fibers 50 can be applied in patches isolated or interconnected along the uppermost surfaces of the hydrophilic base sheet, or, in the case of a relatively flat base sheet, these can be applied in a specific pattern to provide patches either isolated or interconnected from such material, or a combination of regions insulated and interconnected, preferably raised in relation to the surrounding untreated base sheet so that the stack adjacent to the cover material will preferably contact and perceive the smooth hydrophobic regions. Preferably, the fibers have a denier of less than about 9, more specifically less than about 6, more specifically less than about 5, and more specifically from about 1 to about 5. Suitable polymers include ethylene-propylene copolymers, polyester copolymers, low density polyethylene, acrylic, ethylene-vinyl acetate copolymer, polyethylene, polypropylene, chlorinated polyethylene, polyvinyl chloride, polyamide, high density polyethylene, linear low density polyethylene and Similar. Conjugated fibers such as bicomponent or bicomponent sheath / core side-by-side fibers can also be used. The bicomponent fibers with a relatively low melting point material and a higher melting point material in a single fiber can be used by heating the fibers in contact with the base sheet so that the melting point material under melting and adheres the non-melted top melted knit material to the base sheet. Even though continuous filaments of fibers may be employed, the preferred fibers have lengths of from about 0.3 millimeters to about 10 millimeters, more specifically from about 0.5 millimeters to about 5 millimeters, more specifically less than about 3 millimeters. millimeters, and more specifically less than about 2 millimeters. Preferably the bonded fibers have at least one end which is free and can be deformed or deflected under cut to provide a velvety and smooth feel. The fibers must be attached in a fixed manner so that they do not fall off easily or have excessive eschar in use. The bonded fibers can be applied to form a layer of approximately one fiber diameter in depth or one layer having a plurality of fiber diameters in thickness, including from 2 to 100 fiber diameters, more specifically from 3 to 50 fiber diameters or more specifically still from 3 to 10 depth fiber diameters.

The fibers can be part of a preformed non-woven fabric or they can be loose fibers deposited through air placement and is consequently bonded, preferably using a patterned vacuum surface to apply the fibers in a desired pattern, or by apply a fairly uniform mat of short fibers on the surface of the base sheet and joining only the fibers on the uppermost regions of the surface of the base sheet. The latter process may include a heated pressure point in which the raised regions on the base sheet better force the contact between the deposited fibers and the heated textured surface, so that the fibers are thermally bonded to the fabric only at the most high on the base sheet. The high points on the textured heating surface or the heating roller provide a spot welding of the fibers on the base sheet.

A useful method for joining hydrophilic fibers requires first printing or depositing the binder or adhesive material on the outermost regions of a textured base sheet, so that by etching, followed by exposure of the base sheet to the loose fibers carried in the air, as a process of placement by air, in such a way that the fibers are retained by the binder material on the printed regions but not retained elsewhere on the base sheet. The non-adhering fibers can then be removed by blowing air or by vacuum, and then recycled. In this way the thin mats of loose, fluffy fibers can be deposited and bonded on the desired locations on the base sheet, preferably with minimal sheet penetration by the adhesive.

The fibers may be formed directly on the base sheet or deposited immediately after forming using meltblown or spin-bond processes, adapted to provide fibers only in desired regions. Alternatively, a bulky, smooth and thin and continuous layer of preformed spunbond or meltblown fibers can be cut to have perforations on the lower regions of the tissue tissue and then place it appropriately on the tissue and join them by thermal bonding other means. In another embodiment, the fibers may be incorporated in a dilute aqueous solution and applied to the base sheet. This can be done during the formation of the base sheet itself with a layered headbox, resulting in a unitary base sheet containing a part of hydrophobic soft fibers embedded in the top layer of a cellulose sheet in another way . The additional application of a water repellent agent in the uppermost regions of the contoured surface of the base sheet may then be required to ensure that the uppermost regions are sufficiently hydrophobic.

Applicants have found that a contiguous woven of hydrophobic fibers, such as a non-woven fabric spun-bonded or blown with synthetic fiber melt, can be especially advantageous for use as the hydrophobic material of the present invention, offering economical processing and excellent comfort. For effective removal of media, mucus, liquid bowel movement and other viscous fluids, the non-woven fabric should be provided with macroscopic openings, slits or other openings as shown in Figure 14 to provide good access to the base sheet hydrophilic for exudates from the body. The openings or perforations 61 in the non-woven fabric 60 should lie on a part of the depressed regions in the hydrophilic base sheet so that the fluid is repelled by the higher parts of the surface that makes contact with the skin and pull towards depressed regions that are not in direct contact with the skin.

The openings in the non-woven fabric can be provided through a bolt opening; the engraving perf and the mechanical stretching of the tissue; perforation or die stamping; hydroentanglement to impart perforations by rearrangement of the fibers; water blades that cut desired openings or holes in the fabric; laser cutters that cut tissue parts; pattern forming techniques such as air placement or synthetic fibers on a patterned substrate for imparting macroscopic openings as described by FJ Evans in U.S. Patent No. 3,485,706 issued December 23, 1969, and in U.S. Patent No. 3,494,821 issued February 10, 1970, both incorporated herein by reference; needle piercing with sets of barbed needles for hooking and moving the fibers; and other methods known in the art. Bolt drilling of non-woven materials is described in commonly owned United States of America Patent No. 5,188,625 issued February 23, 1993 to Van Iten et al., Incorporated herein by reference.

The openings or perforations can be created in a way that allows an excellent match of the perforations 61 with the depressed regions of a three-dimensional and continuous dried tissue. A modified form of hydroentanglement can be especially useful in this regard. Such a process comprises placing a non-woven fabric 60 on the same type of continuous dryer fabric that is used to mold the associated base sheet during continuous drying. With the non-woven fabric on the continuous dryer fabric, the hydroentanglement can be applied to drive the fibers out of the raised portions of the dried cloth continuously, which will correspond to the depressed regions on the side of the fabric of the sheet of drying through air. If the tissue tissue is to be used with the air side facing the body in the absorbent article, then the non-woven fabric should be placed on the back side of the dryer fabric continuously and then hydroentangled, since the raised portions on the back side of the drying fabric continuously will generally correspond to the depressed regions of the other side on which the tissue is molded.

After the hydroentanglement on a continuous drying fabric has provided the nonwoven fabric 60 with a pattern of perforations 61, the fabric can be placed in register with the continuously dried tissue to place the openings on the depressed regions to result in a taking effective in the hydrophilic depressions while maintaining the hydrophobic material on the elevated portions of the base sheet. The match can be achieved with photoeye and computer program or image analysis software or other mechanical means known in the art to control the position of the non-woven fabric by placing it on the molded base sheet by means of automated equipment.

Preferably, the openings are provided in a regular pattern on at least a portion of the topsheet of the absorbent article.

The transmission of the fluids into the openings into the hydrophilic base sheet can be improved by modifying the surface chemistry of the hydrophobic nonwoven fabric in the area of the openings, such as by adding surfactants to the nonwoven fabric. in the vicinity of the perforations or by oxidation of the fibers by plasma or other treatment. Alternatively, cellulosic fibers or other hydrophilic matter can be added to the region of the openings to increase transmission. For example, cellulosic fibers can be added to the periphery of the openings to improve transmission.

EXAMPLES Example To demonstrate an example of a wet and textured elastic absorbent fabric with an improved dry feel, a suitable base sheet was prepared and modified by the addition of hydrophobic material in the paraffin form. The base sheet was produced on a continuous tissue making machine adapted for drying through non-creped air, similar to the machine configuration shown in Figure 4. The machine comprises a Fourdrinier forming section, a transfer section , a continuously dried section, a subsequent transfer section and a reel. Aqueous solution diluted to approximately a 1% consistency was prepared from 100% fir-bleached chemothermomechanical pulp (BCTMP), pulped for 20 minutes at about a 4% consistency prior to dilution. The spruce BCTMP is commercially available as Tembec 525-80, produced by Tembec Corporation of Temiscaming, Quebec, Canada. The Kymene 557LX wet strength agent, manufactured by Hercules, Inc. of Wilmington, Delaware was added to the aqueous solution at a dose of about 20 pounds of Kymene per tonne of dry fiber. The solution was then deposited on a fine forming fabric and drained with vacuum boxes to form a fabric with a consistency of about 12%. The fabric was then transferred to a transfer fabric (Lindsa wire 952-505) using a vacuum shoe to a first transfer point without a significant speed difference between the two fabrics. The fabric was further transferred from the transfer fabric to a continuous dryer fabric woven at a second transfer point using a second vacuum shoe. The continuous drying fabric used was Lindsay Wire T-116-3 from (Lindsay Wire Division, Appleton Mills, Appleto Wisconsin) based on the teachings of U.S. Patent No. 5,429,686 issued to Kai F. Chi and others. The T-116-3 fabric is well suited to create molded three-dimensional structures. At the second transfer point, the continuous drying fabric is moving more slowly than the transfer fabric with a speed difference of 2.8%. The fabric was then passed over a continuous dryer with cover where the leaf was dried. The temperature of the cover was about 200 degrees F. The dried sheet was then transferred from the dryer fabric continuously to another fabric, from which the sheet was put on a reel. The pilot paper machine for producing the non-creped paper was operated at a speed of approximately 20 feet per minute. The basis weight of the dry base sheet was approximately 39 grams per square meter (grams per square meter) the sheet has a thickness of 0.64 millimeters when measured with a plate meter at 0.05 pounds per square inch, for a volume dry of 16.4 cc / g. The depth of surface is around 0.42 millimeters.

Samples of the base sheet were conditioned under Tappi environmental conditions for several days, then cut into a number of sheets of 6 inches by 12 inches which were then treated with paraffin wax using a variety of methods. A rectangular Gulfwax ™ paraffin board for domestic crushing was used to apply a small amount of wax on the fabric side surface of the non-creped base sheet produced as described above. Several sheet samples were individually heated on a Corning PC-351 hot plate set at a low power level of 2.5. Samples were kept in light contact with the heated surface by hand for 5 to 10 seconds and then removed and placed on a table. The wax plate was then immediately drawn onto the heated sample surface to deposit a small amount of wax on the higher regions of the upper surface. In one version, the side of the base sheet fabric was in contact with the heated surface while in a second version, the air side of the base sheet was heated. In application of the wax, the plate was maintained at an angle of about 30 degrees in relation to the plane and the lower end of the plate was placed on the base sheet. The plate was then dragged with light force (estimated as around 0.5 to 1 pound) over a full surface of the base sheet so that the contact end of the plate was then the tail edge. Care should be taken to apply the wax uniformly. The objective was to avoid the melting of the wax since the melted wax would impregnate the base sheet and would not remain on the surface, but to request the deposit of wax on the base sheet through heat. The heating and the wax treatment was done successively on the sections of about 3 square inches or 6 square inches until the full base sheet sample was treated. The wax plate was weighed before and after the application. The typical amount of wax applied to the base sheet of 6 inches by 12 inches was around 0.06 g.

With the subsequent wetting of the resulting absorbent fabric, the small upper sections of the wax-treated fabric appeared slightly lighter than the untreated regions, as if the wax had trapped some of the air near the fibers. Based on physical appearance, it was evident that the wax was preferentially distributed over the uppermost regions of the base sheet surface, occupying a small fraction of the total surface area estimated as being around 10%.

The average rewet values for Wax treated and untreated samples are shown in Table 1. The average normalized rewet values are also listed (rewet divided by the conditioned dry mass of the sample). The graph in Figure 15 shows the mean values and the 95% confidence intervals about the media (1.96 * standard deviation / square root of sample size). Paraffin treatment resulted in a significant decrease in rewetting. The decrease in the rewet value is presumed to be indicative of a drier feeling if the tissue is moistened in contact with the skin, since less fluid can pass through the local elevated hydrophobic barriers to make contact with the skin. The wax-treated samples also feel slightly less sandy than the untreated samples, apparently due to a degree of lubricity provided by the paraffin on the higher parts of the treated surface.

Table of Rehumidity Values for Example 1 Example 2 In order to further illustrate this invention, the non-creped continuous dried tissue base sheet was produced using the method substantially as described in Example 1. More specifically, a single stratum single layer fibrous tissue was made bleached quimotermomecánica pulp of soft wood of the north not refined (BCTMP). After the pulp reduction and dilution of the BCTMP fibers, the Kymene 557LX was added to 20 kilograms per metric ton of pulp. The fabric formation in this case was an Appleton Wire 94M fabric and the first transfer cloth was a Lindsay 996 fabric. The rapid transfer was carried out at the first transfer point, during the transfer from the forming fabric to the fabric. Lindsay 956 transfer. The degree of rapid transfer was 35%. The differential velocity transfer process used the vacuum shoe geometry taught in U.S. Patent No. 5,667,636, issued March 4, 1997 to S. A. Engel et al., Previously incorporated herein by reference. At this second transfer point, from the transfer fabric to the dryer through air, both fabrics were running at essentially the same speed of about 40 feet per minute. The fabric was then transferred to a continuous drying fabric (Lindsay Wire T-116-3). The continuous drying fabric was moving at a rate essentially the same as the transfer cloth. The fabric was then carried on a continuous dryer operating at a cover temperature of about 315 degrees F and dried to a final dryness of about 94-98 percent consistency. The base weight of the fabric was 60 grams per square meter.

The resulting non-creped continuous dried tissue base sheet was used in flat permeability measurements using a two-disc stack, giving a value of 1.87 by 10"10 square meter.The wet elasticity test gave a WCB value (Humid Compressed Volume) of 9.65 cc / g, a return spring of 0.889, and an LER of 0.824. The volume measured at 0.1 pounds per square inch was 16.2 cc / g.

After several weeks of storage under Tappi environmental conditions, the base sheet was then treated with paraffin wax essentially as described in Example 1. Two strips of 12 inches by 6 inches were prepared. For each strip, the cloth side of a 6-inch square region was heated in contact with the Corning PC-351 hot plate at a power setting of 2.5 for about 5 seconds, then it was removed and placed on the the fabric up on a flat surface. A paraffin wax plate was then dragged on the surface to deposit about 0.06 g of wax on the surface of the first strip and 0.07 g of wax on the surface of the strip. second. The two strips were then cut into segments of 4 inches by 6 inches. The two strips were then cut into segments of 4 inches by 6 inches. All segments of the first strip (labeled 1A, IB and 1C) were tested for rewetting and a segment of the second strip was also tested with respect to 3 similar untreated strips of the same base sheet (labeled 3, 4 and 5). ). The results are shown in Table 2. The rewet values for the waxed segments were significantly lower than those of the untreated samples with the exception of the IA segment which had a similar value to the untreated samples. This sample was excessively wetted beyond the recommended range for the test, so that additional available moisture may have inflated the rewet value. However, it is suspected that the waxing operation may have been carried out poorly in the region that was subsequently in contact with the Whatman filter paper during the test. The main rewet for the waxed samples, excluding sample 1A, is 0.467 g compared to the untreated medium of 0.689 g, an apparent reduction of 32%. Normalized rewetting also falls significantly due to hydrophilic treatment. Here, the rewet values less than 0.68 g are taken as evidence of an improved dry sensation.

Table 2: Rewet values for Example 2 To determine if the small amount of the presumably dominant surface wax applied to the textured base sheets had any adverse effect on the total absorbent capacity, the tested segments were completely submerged in the tap water and then maintained by a corner and they were allowed to drain for 60 seconds, and then weighed. The "wet runoff" for the untreated samples 3 and 5 was 7.8 and 8.3 g, respectively. The "wet runoff" for samples IA, IB and IC was 7.44, 7.55, and 7.9 g, respectively. For sample 2, it was 8.00 g. Given the variability and overlapping of the data ranges for the treated and untreated samples, there is no clear evidence of a significant decrease in the absorbent capacity of the waxed samples.

Examples 3-6 In order to further illustrate a method for making absorbent fabrics of this invention, the base sheets were produced using elastic, unmoistened soft northwood kraft fibers (NSWK), with and without a wet strength agent (20 pounds Kymene per ton of fiber), and wet elastic fibers (BCTMP spruce), with and without a wet strength agent (20 pounds Kymene / tonne of fiber) using a non-creped continuous drying process essentially as shown in Figure 4.

The fiber was pulped to a consistency of 4% in the pultruded hydro-reducer for 30 minutes. The fiber was pumped into a supply chest and diluted to a 1.0% consistency. 20 # / tons of Kymene 557LX were added to the supply box and allowed to mix for 30 minutes. A single layer, mixed sheet of 30 grams per square meter of dry weight was formed on an Albany 94M forming fabric and drained with 5 inches (127 mm) of mercury vacuum. The forming fabric was moving at 69 fmp (.35 meters per second). The sheet was transferred to a fast 15% transfer to a Lindsay 952-S05 transfer cloth moving at 60 fpm (.30 meters per second). The vacuum in the transfer between the forming fabric and the transfer fabric was 10 inches (254 millimeters) of mercury.

The sheet was transferred with vacuum to 12 inches (305 millimeters) of mercury to a continuous form dryer fabric (Lindsay T-116-1) moving at the same speed as the transfer cloth 60 fmp (.30 meters per second). The sheet and the continuous dryer fabric were moved over a vacuum room to 12 inches (305 millimeters) of mercury just before entering a continuous Honeycomb dryer operating at 200 degrees F (93 degrees Celsius) and dried at a final time of one hour. 94-98% consistency.

The base leaves were aged for 5 days at less than 50% humidity at 70 degrees F (21 degrees Celsius). The base sheets were tested for physical characteristics in a controlled environment of 50% ± 2% humidity and 23 degrees Celsius ± 1%. The wet and dry strength was tested on an Instron apparatus with a sample width of 7.62 centimeters, a jaw extension of 10.16 centimeters and a crosshead speed of 10 inches / minute (25.4 centimeters / minute). The caliper was measured with the TMI tester at 0.289 pounds per square inch.

The results of physical property are shown in the Table of Figure 16. Example 6 exhibited essentially higher elasticity, as measured by the wet wrinkle recovery test than the other three samples. In addition, the Example 6 also showed a ratio of wet: high dry. The properties of Example 6 in particular make it suitable for use as a base sheet which can be calendered and then recover much of its volume with wetting. When treated with hydrophobic materials such as silicones or talcum powder, such calendered absorbent fabric can provide a high strength and dry feel when the hydrophilic regions rise from the rest of the sheet after wetting.

Examples 7-10 Additional examples similar to those described in Examples 3-6 were carried out, but for the purpose of exploring the effect of the basis weight on the wet, absorbent and bulky elastic structure. There were four base weight levels of 30, 24, 18 and 13 grams per square meter of 100% BCTMP fir with 20 # / ton Kymene.

The fiber was pulped to a consistency of 4% in the pultruded hydroreductor for 30 minutes. The fiber was pumped into a supply chest and diluted to a 1.0% consistency. 20 # / tons of Kymene 557LX were added to the supply box and allowed to mix for 30 minutes. A single-layer blended sheet was formed on an Albany 94M forming fabric and drained with 4 inches (102 mm) of mercury vacuum. The forming fabric was moving to 69 fmp (.35 meters per second). The sheet was transferred to a rapid 15% transfer to a Lindsa 952-S05 transfer cloth moving at 60 feet per minute (.30 meters per second). The vacuum in the transfer between the forming fabric and the transfer fabric was 7 inches (178 millimeters) d mercury. The sample of 13 grams per square meter was produced without a rapid transfer, the forming fabric was moving at 60 feet per minute (.30 meters per second), same as the transfer fabric and the continuous dryer fabric.

The sheet was transferred with vacuum to 254 millimeters of mercury to a continuous dryer fabric (Lindsay T-116-1) moving at the same speed as the transfer fabric, 60 feet per minute (.30 meters per second). The continuous dryer sheet and tel were moved over an empty room to 1 inch (279 millimeters) of mercury just before entering the Honeycomb continuous dryer operating at 260 degrees F (127 degrees Celsius) and drying to a final dryness of 94 -98% d consistency.

The base leaves were aged for 5 days less than 50% humidity at 70 degrees F (21 degrees Celsius). The base sheets were tested for physical characteristics in a controlled environment of 50% ± 2% humidity and 23 degrees Celsius ± 1 degree. The resistance to moisture and e dry were tested with an Instron apparatus with a sample width of 3 inches (7.62 centimeters), a jaw extension of 4 inches (10.16 centimeters) at a crosshead speed of 10 inches / minute (25.4 centimeters / minute). The caliper was measured with the TMI tester at 0.289 pounds per square inch.

The physical property results are summarized in the Table of Figure 17. As shown, the Examples 7-10 exhibited a high resistance to moisture as determined by the wet wrinkle recovery test and compressive wet elasticity tests. The materials such as the fabric of Example 10 are especially suitable as a base sheet for receiving hydrophobic material in the production of a calendered and dense absorbent fabric which can quickly absorb the liquid and then return to a bulkier structure having a hydrophilic material on it. the uppermost regions to provide a dry and clean feeling. Typical commercial paper and tissue towels generally have wet return ratios of less than 0.7, WCB values of less than 6, and LER values of less than 0.7. Similarly, such materials tend to have flat permeability values of 0.4 by 10"10 square meters.

Examples 11 v 12 For Examples 11 and 12, the side of the fabric of the base sheet of Example 1 was treated with adhesive sprays to create sparse hydrophobic regions, some of which were further treated with a hydrophobic powder. For Example 11, a spray of a 3M # 72 pressure sensitive adhesive was used to randomly cover about 30% of the surface area of the base sheet with a blue, flexible, soft and low tack adhesive material. The tackiness was further reduced by spraying a small amount of lipocodium powder (also known as club fungus spores, commercially available from EM Science, Gibbstown, New Jersey) on one part of the woven and talcum powder on another part for selectively adhere to the adhesive and remove the sticky feeling. Unbound dust was shaken. For Example 12, the sprayed adhesive used was 3M # 90 high strength adhesive, which was sprayed randomly and lightly to give patches scattered about a half inch to 1 inch in diameter containing adhesive on the top surface. The stickiness was again reduced by spraying talcum powder or lycopodium powder on various parts of the fabric and removing excess dust. When the tissues were moistened, the hydrophobic regions containing adhesive and hydrophobic powder felt somewhat drier than the untreated regions. The regions containing adhesive of Example 12 They were noticeably stiffer than the surrounding base sheet and would be unsuitable for many products. The lower viscosity of the adhesive used in Example 12 also resulted in a relatively greater penetration of the adhesive into the absorbent tissue relative to Example 11, so that the adhesive patches of Example 12 appeared lighter than the surrounding untreated regions in where the absorbent tissue was completely wetted with water.

Example 13 Additional non-creped air-dried base sheets were made according to Example 2. Example 13 differed in having 10 pounds of Kymene per ton of dry fiber in the supply, had 15% rapid transfer and comprised 75%. % kraft fibers from soft northern wood and 25% BCTMP spruce. As with Example 2, the basis weight was 60 grams per square meter and the air drying fabric was a Lindsay Wire T-116-3 fabric. The ratio of wet back spring was 0.839, the WCB was 7.5 cc / gm, and the LER was 0.718. The in-plane permeability was 0.84 per 10"10 square meter.

The base sheet of Example 13 could be made in a fabric of the present invention by knife-coating the upper surfaces of the side of the base sheet fabric with a low hydrophobic, flexible hot-melt adhesive at an elevated temperature immediately followed by air placement of fine synthetic fibers having an average length of about 1 millimeter on the side containing tissue adhesive, followed by light air jets to blow and recover unbound fibers. Cooling jets may be desired to remove the stickiness of the adhesive prior to putting on a reel. The tack reduction of the exposed adhesive can also be achieved by the addition of particles carried in air jets applied to the treated fabric, said particles comprising talc, sodium bicarbonate, titanium oxide, zinc oxide, miscellaneous fibers known in papermaking. Similar.

The above samples serve to illustrate the possible approaches pertaining to the present invention in which improved dry feel and other properties are achieved through novel combinations of textured and elastic base sheets with hydrophobic matter. However, it will be appreciated that the foregoing Examples, given for purposes of illustration, should not be considered as limiting the scope of the invention which is defined by the following claims and all equivalents thereof.

Example 14 A non-woven fabric bonded with 0.6 oz. Polyethylene yarn per square yard was laminated with construction adhesive to the side of the fabric of a fabric dried through non-creped air of 40 grams per square meter comprising 100% spruce fibers. BCTMP and textured by means of continuous drying on a Lindsay Wire T-216-3 fabric. A strip of cellulosic fabric placed by air was prepared and had been densified and stabilized with about 1% thermoplastic fibers which melted during heating to maintain the fiber at a constant density of about 0.2 g / cc. The 1 inch wide strip was placed below the non-creped base sheet with the nonwoven fabric held over the top. The fluid intake was tested by placing dyed water drops on the upper surface. The water quickly penetrated the base sheet of the tissue and then into the stack placed by air, resulting in the majority of the fluid being held by the material placed by air. When colored drops of water were placed on the laminated fabric without an absorbent placed by underlying air, the fluid spread over a much larger area on the base sheet than when the strip placed by air was present.

A mixture of about equal parts of egg white and water, with some food coloring was prepared of commercial class added, to simulate the intake of viscoelastic fluids such as mucus fluids or menstrual fluids. The solution was gently shaken to establish a uniform consistency. The solution was then applied as drops of about 0.3 millimeters to about 1 millimeter to the surface of the intake material with the strip placed by air underneath. The shot seemed very low or was still completely prevented by the non-woven material. The tip of a blade was then used to scrape a small part of the non-woven fabric, resulting in an opening about 0.2 millimeters wide and 2 millimeters long. A drop of egg white solution applied to the opening penetrated inside the hydrophilic in a few seconds, much more quickly than without the opening, but even more slowly than the less viscous and non-visco-elastic colored water.

Example 15 To demonstrate the potential of the perforated non-woven fabrics in the present invention, three non-woven fabrics bonded with polyethylene yarn having a basis weight of 0.4, 0.6 and 0.8 ounces per square yard (osy) were purchased. The fabrics were perforated using a roller device for a twin opening. The metal bolts were mounted in the holes in the arched metal plates that could be screwed onto the middle section of an upper roller. The Matching metal plates with holes mounted on the lower roller received the upper tapered portion of the bolts on the upper roller. Two different bolt diameters of 0.109-inch and 0.187 inch were used. The holes for receiving and retaining the bolts were arranged in a bilaterally stepped grid. The 0.187-inch bolts were placed in each hole in the array on a 2-inch-wide strip around the top roller. The perimeter of the roller is 36 inches. The 0.187 inch bolts were therefore spaced apart at intervals of about 0.25 inches from center to center along any row. The 0.109 inch bolts were spaced over a 4 inch wide strip of bilaterally staggered holes, bolts loaded only in alternating rows and in any row containing bolts, loaded only into each other hole in that row. With 11 bolts in each row 4 inches wide, bolts loaded at 0.109 inches are spaced by about 0.4 inches from center to center. To improve the quality of the perforation, the upper roller containing the bolts was heated to around 200 degrees F and the lower roller, which makes contact with the non-woven fabric, was electrically heated to 150 degrees F. These are measured temperatures inside the roll. Using a surface thermocouple, the upper surface temperature of the upper roller was measured at 150-158 degrees F. Using the 0.109 inch bolts first, the drilling device was driven at 50 feet per minute and used to drill lengths of material bonded with polyethylene yarn having a basis weight of 0.4, 0.6 and 0.8 ounces per square yard. Then the plates containing bolts were changed to allow drilling with 0.187 inch diameter bolts, also at 50 feet per minute and all three base weight materials joined with spinning were drilled. The perforated nonwoven fabric appeared soft and suitable for use as a feminine care material. The samples of the non-woven fabrics were then cut and placed on the sections of the dried non-creped continuous material made according to Wendt et al., Previously incorporated by reference and textured on a Lindsay Wire three-dimensional continuous drying fabric. according to Wendt and others and Chiu and others, also previously incorporated by reference.

The 3M pressure-sensitive spray adhesive was used at one point to bond the tissue base sheet and the non-woven fabric, attaching the perforated nonwoven to the textured non-crepe tissue which was simplified by the natural mechanical affinity of the tissue surface for the curled non-woven surface. The engagement of the fibrils apparently allows the non-woven layer to adhere reasonably well, even though it is preferred to create a more intimately bonded structure through any adhesive bond, ultrasonic bonding, thermal bonding and the like.

Example 16 The composite top sheet structures were prepared by adhering the perforated fabrics of Example 15 to the textured, non-creped and air-dried base sheets similar to those described in Examples 1-10. Adhesion was achieved with a specialty adhesive transfer paper comprising a coated release paper printed with spots of adhesive, so that the points can be transferred to other surfaces by means of a gentle application of pressure. A hot melt construction adhesive, National Starch No. 5610, printed on a release paper coated through a printing grid with a New England Rotary grid, 40-NERO-SF0001 was used. To attach a perforated non-woven fabric to the textured tissue paper, the adhesive transfer paper was placed with the adhesive spots in contact with the textured tissue and then lightly pressed with a rubber roller to a load of less than 0.5 pounds per inch. linear so that the fabric was not essentially flattened by the roller and so that a portion of the adhesive spots were transferred to the higher portions of the fabric. The perforated nonwoven fabric was then superimposed on the tissue. In the placement of the non-woven fabric on the tissue, the side of the non-woven fabric that made contact with the tissue was the side which was away from the roller by holding the pins during the drilling process. cap screw. The tissue facing side of the non-woven fabric has protrusions surrounding each opening where the pin has forced some of the polyolefin material out of the plane of the non-woven fabric during the bolt-piercing process. In some cases, it may be preferable for such protrusions to reside primarily in depressed regions of the underlying tissue tissue to provide a bridge of near continuous material from the face-to-body side of the non-woven fabric to the surface of the tissue, so that the fluid does not require crossing any significant interfacial spacings between the two or more layers of the top sheet.

For these examples, only non-woven yarns of base sheet 0.4 oz. Per square yard were used. The base sheets were all non-creped air-dried tissue fabrics and no layers made according to the principles given in Examples 1-10, with the exception that the basis weight, the type of fiber, the fast transfer and the types of fabric were varied. The "upper texture" refers to fabrics made with about 30% fast transfer on a Lindsay T-216-3 wire cloth as the transfer cloth followed by drying continuously on a T-216-3 fabric. The "flat" tissue was continuously dried on a traditional flat continuous drying fabric lacking top surface depth. The "medium texture" refers to fabrics made with 8% fast transfer on a wire cloth Lindsay T-216-3 as the transfer cloth, followed by continuous drying on a Lindsay T-216-3 wire cloth. All fabrics had about 20 pounds of Kymene per ton of fiber added for wet strength. The following combinations of nonwoven and base sheet were tested: Table 3. Tested Compounds for Taking In some cases the cover material was combined with a thin absorbent layer consisting of another sheet dried through uncreped air or a strip placed by air. These absorbent layers include: Abs. A: a "high texture" fabric of 100% BCTMP (sample 1 of Table 3); Abs. B: a "flat" fabric of 100% BCTM (sample 4 of Table 3); Abs. C: a 100% non-creped BCTMP fabric dried continuously on a wire cloth Lindsay Wire 134-10: Abs. D: a "medium texture" fabric comprising bleached softwood (sample 6 of Table 3).

In addition, the air-laid strip of Example 14, which has a basis weight of about 200 grams per square meter, was also used in some tests. The absorbent layer was simply placed under the cover composed of either mechanically bonded or adhesives. In some cases, the lightweight adhesive may be desirable to hold the cover over the absorbent core.

To demonstrate the adequacy of the perforated fabrics of Example 15 for taking menstrual fluids, a simple menstrual fluid simulator was used. The simulator was a 50:50 sample of fresh egg whites and water, with an added fugitive dye. The mixture was prepared by separating the egg whites from the yolks of two large eggs (from Sparboe Farms, Litchfield, Minnesota) that had been removed from the refrigeration and placed in a room at a temperature of about 72. degrees F by 6 hours. The egg white mass was 60.0 g. An additional 60 grams of deionized water was added to the egg whites in a 250-milliliter beaker and shaken vigorously in the beaker with a laboratory spatula for about 3 minutes, taking care to avoid foaming. The resulting mixture appeared slightly cloudy and still showed signs of proteinaceous strands in the fluid that had a different refractive index than other parts of the solution. It was agitated by gently adding 2 additional milliliters of a dye solution. The dye solution was prepared by adding 40 ml of purple Versatint II due to (Milliken Chemical, Inman, South Carolina) to 1,000 milliliters of deionized water.

The colored egg white solution was applied to the surface of the top sheet material composed with an Eppendorf pipette applied to apply drops of 0.5 milliliters. The drop was applied to the top surface of the top sheet within an interval of 3 seconds, taking care to apply the drop gently and gently. Initially the drop clustered, resting on the unmoistened surface like a flattened sphere several millimeters in diameter, wide enough to engage at least one opening, typically no matter where the drop was placed. Visual observation was then used to identify the time required for the transmission to occur in the plane of the underlying base sheet, and the additional time after the start of the transmission for that the droplet is essentially removed from the surface of the non-woven fabric, so that substantially no liquid remains substantially above the plane of the non-woven fabric. The first time, when the time for visible transmission began, was called the "entry time" and was detected when the colored fluid could be seen extending horizontally on the base sheet beyond the margins of the drop on the part. higher. The second time, the time for substantial removal of the liquid from the drop on the non-woven surface was termed the "transmission time". The sum of the two times is the "take time". The results are shown for several tests in Table 4. The best results are obtained with larger bolt openings. With the smallest openings, the hydrophobic fibers in the protrusion on the back side of the tissue formed during perforation may have been flattened to partially close the openings during attachment to the tissue of uncreated tissue.

Table 4. Results of Taking Egg White Solutions for the Compounds of Table 3 It is believed that the intake rates can be significantly increased by increasing the exposed area of the base sheet.

By placing the drops of the egg white solution directly on the BCTMP and on the leaves In this way, it was observed that the BCTMP offers a faster take, apparently due to the greater open pore structure of the BCTMP sheet. Densified air-laid strips with a density of about 0.2 cc / g can also give rapid take-up of the solution.

Example 17 The ability of the present invention to serve as an improvement over perforated films can be seen in this Example where a wet hydrophilic base sheet is provided with a non-planar perforated structure and then non-compressively dried to impart high moisture resistance , followed by printing or coating the hydrophobic material on the higher regions of the body-contacting side of the perforated fabric, resulting in a composite material having hydrophilic openings and a hydrophobic top surface. In particular, a flexible and soft fabric of basis weight of from about 10 grams per square meter to about 100 grams per square meter, more preferably from about 20 grams per square meter to about 50 grams per square meter, during the fabrication was drilled before the fabric had dried above about 60% solids, and preferably before the fabric had dried above about 40% solids. The fabric can be relatively flat or textured before perforation.

The perforation can be made by protrusion on a roller that makes contact with the body side of the fabric while remaining on a surface having matching depressions, so that the intermixing of the protuberances and depressions causes the perforations to extend away from the surface. contact side with the body of the tissue to create a non-planar three-dimensional topography with the tissue regions adjacent to the openings having some fiber orientation in the z-direction. The openings in the base sheet can also be created by drilling, perft-engraving, stamping or differential air pressure. The differential air pressure may be used when the fabric resides on a perforated but otherwise low permeability carrier. The weak wet weave that resides on a perforated surface allows the air pressure to cause parts of the fibers on the perforations to deflect and break free from the plane of the fabric and descend partially in the z direction. After the 3-D perforations are created in the wet state, the fabric must be dried to complete without significantly interrupting the perforated or perforated state that has been achieved. The fabric structure will then have a high wet elasticity, particularly if low performance fibers or moisture resistance additives are used. As a result of this, the base sheet is provided with openings and the bottom surface of the base sheet is provided with fibrous protuberances descending from the base sheet. which are adjacent to the openings and can surround or partially surround the openings, forming hydrophilic opening walls. The protrusions or perforation walls, by virtue of being dried in the three-dimensional state, also have good wet elasticity, or a tendency to maintain wet elasticity, or a tendency to maintain the shape and orientation in which they were still dried after being wetted, especially if high performance fibers or wet strength agents were used to make the fabric. Preferably, the openings have an open area of at least 15% and more preferably of at least 30%, and have a characteristic or effective diameter preferably of from about 0.2 millimeters to about 4 millimeters, more specifically from about 0.3 to about 2 millimeters, and more specifically about 0.5 millimeters or greater.

After non-compressive drying, the contact side with the tissue body (the side away from the descending sides of the openings) was treated with hydrophobic material. This can be printed on the tissue in discontinuous droplets or spaced apart and thin regions. Alternatively, the fabric can be coated or printed with a smooth printing surface by having a film of the hydrophobic material in the melted liquid state or in a solution state. Waxes or mixtures of wax, oil and opacifiers can be essentially preferred. The resulting structure has high hydrophobic regions while the walls of the openings descending outward from the hydrophobic material are still hydrophobic. The hydrophobic material is intimately bound to the surface of the hydrophilic fabric. Because the base sheet is providing structural integrity, the hydrophobic material may be continuous but weak or discontinuous and generally would not be expected to be able to be removed from the base sheet without being severely damaged or disintegrated. This provides a dry sensation on one side of the body and, if properly selected, can improve the softness, the pleasant sensation of the cover. The underlying base sheet provides excellent absorbency and provides ducts such as additional perforated films for direct flow to the absorbent core. However, the plane transmission and the flow channels below the base sheet will provide good fluid handling and absorbent capacity.

It will be appreciated that the foregoing Examples, used for the purposes of illustration, are not to be construed as limiting the scope of this invention, which is defined by the following claims and all equivalents thereto.

Claims (39)

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

1. An absorbent weave that has a dry sensation when moistened which comprises: a) an inherently hydrophilic base sheet comprising fibers for making paper and having a top surface and a bottom surface, said top surface having high and depressed regions; Y b) hydrophobic material deposited preferably on the elevated regions of the upper surface of said base sheet.

2. The absorbent fabric as claimed in clause 1 characterized in that said base sheet is a sheet of tissue placed wet.

3. The absorbent fabric as claimed in clause 1 characterized in that said base sheet is a structure placed by air.

4. The absorbent weave as claimed in clause 1 further characterized in that it has a wet back or spring ratio of about 0.7 or greater.

5. The absorbent fabric as claimed in clause 1 characterized in that the hydrophobic material is decontaminated.

6. The absorbent fabric as claimed in clause 1 further characterized in that it has a rewet value of about 0.65 g or less and a normalized rewet value of about 0.6 or less.

7. The absorbent fabric as claimed in clause 1 characterized in that said base sheet has an overall surface depth of about 0.2 millimeters or greater, in a plane permeability of at least 0.5 by 10"10 square meter, and a wet compressed volume of about 5 cubic centimeters per gram or more.

8. The absorbent fabric as claimed in clause 1 characterized in that said hydrophobic material comprises synthetic fibers fixedly attached to the upper surface of such base sheet so that about 50% or less of the surface area of the base sheet It is covered with synthetic fibers.

9. The absorbent fabric as claimed in clause 1 further characterized in that it comprises hydrophobic material on a part of the lower surface of said base sheet.

10. The absorbent fabric as claimed in clause 1 characterized in that said fabric has an overall surface depth of about 0.2 millimeters or less while it is dry and an overall surface depth of about 0.3 millimeters or greater when wetted a moisture content of 100%.

11. The absorbent fabric as claimed in clause 1 characterized in that said base sheet has a wet tension: dry ratio of at least 0.1.

12. The absorbent fabric as claimed in clause 1 characterized in that said raised regions comprise from 5 to 300 protuberances per square inch having a characteristic height of at least 0.2 millimeters in relation to said depressed regions.

13. The absorbent fabric as claimed in clause 1 characterized in that at least 30% of the upper surface of said base sheet remains essentially free of hydrophobic material and said base fabric has a rewet value of 0.6 g or less.

14. The absorbent weave as claimed in clause 1 characterized in that essentially all the hydrophobic material resides above 50% of the material line of a cross-section characteristic of said weave.

15. The absorbent fabric as claimed in clause 1 further characterized in that it comprises superabsorbent particles attached to said base sheet.

16. A zoned fabric in a dual absorbent form that provides a dry feel in use, said fabric has a top surface comprising a plurality of hydrophobically treated regions surrounded by inherently hydrophilic cellulosic regions, wherein with the wetting said tissue is expanded in a manner that the hydrophobically treated regions are preferably elevated in relation to the hydrophilic regions.

17. A calendered hand towel comprising the fabric as claimed in clause 16.

18. An absorbent fabric having a rewet value of about 1 gram or less, comprising: a) an inherently hydrophilic base sheet which comprises fibers for making paper and having an upper surface and a lower surface, said upper surface having high and depressed regions with an overall surface depth of 0.2 millimeters or greater in the uncalendered and non-creped state, said base sheet furthermore it has a moist compressed volume of at least 6 cubic centimeters per gram; Y b) hydrophobic material deposited preferably on the elevated regions of the upper surface of said base sheet.

19. The absorbent fabric as claimed in clause 18 characterized in that said base sheet is a structure placed by air.

20. An absorbent article comprising the absorbent fabric as claimed in clause 18.

21. An absorbent fabric that has a dry sensation when moistened, comprising: a) an inherently hydrophilic base sheet comprising fibers for making paper and having an upper surface and a lower surface, said upper surface having raised and depressed regions with a depth of global surface of about 0.2 millimeters or greater; b) an essentially contiguous network of hydrophobic fibers having a plurality of macroscopic openings attached to the upper surface of said base sheet so that a portion of the depressed regions of the base sheet are aligned with openings in the overlying network of hydrophobic fibers to allow exudates from the body to pass through the macroscopic openings in the base sheet.

22 The absorbent fabric as claimed in clause 21, characterized in that said network of hydrophobic fibers comprises a plurality of macroscopic openings having a characteristic width of about 0. 2 millimeters or greater.

23. The absorbent fabric as * is claimed in clause 21 characterized in that said base sheet is further characterized by a ratio of wet tensile strength: dry at least about 0.1 or higher and a spring ratio wet return of around 0.55 or higher.

24. The absorbent fabric as claimed in clause 21 further characterized in that a rewet value of about 0.65 g or less and a value of normalized rewet of about 0.6 or less, said base sheet further comprises about 20% or more by weight of high yield pulp fibers.

25. The absorbent fabric as claimed in clause 21 characterized in that the surface basis weight of said hydrophobic material is from about 1 to about 10 grams per square meter and said base sheet has a basis weight of from about 10. at around 70 grams per square meter.

26. The absorbent fabric as claimed in clause 21 characterized in that said base sheet is a structure placed by air.

27. The absorbent fabric as claimed in clause 21 characterized in that said base sheet is a wet laid fabric.

28. The absorbent fabric as claimed in clauses 1 or 21 characterized in that said base sheet further comprises perforations and said lower surface of the base sheet further comprises wet elastic protrusions adjacent said perforations.

29. An absorbent fabric that has a sensation Dry when wet, which includes: a) an inherently hydrophilic base sheet comprising fibers for making paper and having an upper surface and a lower surface, said upper surface having elevated and depressed regions, said base sheet furthermore has a wet tension ratio: dry at least 0.1; Y b) a contiguous network of hydrophobic material deposited preferably on the elevated regions of the upper surface of said base sheet.

30. An absorbent article with a lining • from side to body that comprises the fabric of any clause 21 or clause 29.

31. An absorbent article comprising a liquid impermeable bottom sheet, a cellulosic absorbent core in a superimposed relationship with said bottom sheet, and a liquid permeable absorbent fabric, said absorbent fabric comprising an inherently hydrophilic base sheet comprising fibers for making paper, said base sheet has an upper surface and a lower surface, said upper surface has elevated and depressed regions, which further comprise a contiguous perforated fabric of non-material hydrophobic tissue attached to the upper surface of the base sheet so that a portion of said perforations lies on the depressed regions of the base sheet, wherein the base sheet is superimposed on the absorbent core with the lower surface of the sheet of base facing the absorbent core.

32. An absorbent article comprising a liquid impermeable bottom sheet, a cellulosic absorbent core in a superimposed relation with said bottom sheet, and a liquid permeable absorbent fabric, said absorbent fabric comprising an inherently hydrophilic base sheet comprising fibers for making paper and having a wet tension: dry ratio of at least 0.1, said base sheet having an upper surface and a lower surface, said upper surface having elevated and depressed regions and a hydrophobic material preferably deposited on the raised regions, wherein the base sheet is superimposed on the absorbent core with the bottom surface of the base sheet facing the absorbent core.

33. A take-up material for an absorbent article comprising a perforated non-woven top layer and a three-dimensional continuous dried cellulosic base sheet layer having a pattern of raised and depressed regions, wherein the perforations of the top layer they are essentially in coincidence with the depressed regions in the lower cellulosic layer.

34. The taking material as claimed in clause 33 characterized in that the nonwoven top layer is a hydroentangled fabric of synthetic fibers.

35. An absorbent article comprising the intake material as claimed in clause 33 and a densified absorbent material adjacent to the base sheet and separated from the nonwoven top layer, wherein the densified absorbent material has a density greater than that of the absorbent material. density of the base sheet.

36. A method for producing an absorbent fabric having a dry sensation when wetted comprising the steps of: a) preparing an inherently hydrophilic base sheet comprising fibers for making paper and having an upper surface and a lower surface, said upper surface having elevated and depressed regions; Y b) depositing hydrophobic material preferably on the elevated regions of the upper surface of said base sheet.

37. The method as claimed in clause 36 characterized in that said step of preparing the base sheet comprises the steps of depositing an aqueous solution of fibers to make paper on a perforated weave to produce an embryonic tissue; molding said fabric on a three-dimensional substrate; and drying said tissue.

38. A method for producing an absorbent article comprising the steps of: a) preparing a wet elastic cellulosic base sheet having high and depressed regions, an overall surface depth of at least 0.2 millimeters and having an upper surface and a lower surface; b) integrally holding a fibrous and contiguous nonwoven fabric having a plurality of openings on the upper surface of the cellulosic base sheet so that a portion of the openings are superimposed on the depressed regions of the cellulosic base sheet; c) attaching the bottom surface of the base sheet to an absorbent core and an impermeable fabric, so that the absorbent core is placed in sandwich form between the waterproof fabric and the base sheet.

39. A method for producing a take-up material for an absorbent article comprising the steps of: a) forming an embryonic paper tissue of an aqueous solution of papermaking fibers; b) continuously drying the embryonic tissue tissue on a continuous three-dimensional drying fabric having a pattern of elevated and depressed regions; c) complete the drying of the tissue; d) perforating a non-woven fabric by means of hydroentanglement, wherein the non-woven fabric lies on a carrier fabric having essentially the same pattern of elevated and depressed regions as that of the drying fabric in continuous form of step (b); e) attaching the perforated nonwoven fabric to the continuously dried paper fabric so that the perforations of the nonwoven fabric are substantially aligned with the depressed regions of the continuously dried paper web. R E S U E N An elastic, three-dimensional, dual-zone absorbent fabric is described which is suitable as a side-to-body liner for absorbent articles such as pads for women, diapers and the like. When used as a liner in absorbent articles, the dual-zoned fabric combines the advantages of perforated films and non-woven and soft cover layers in a structure while still remaining inherently hydrophilic. The liner comprises a wet elastic hydrophilic base sheet fabric having a three dimensional topography which comprises raised regions on which the hydrophobic material is deposited or printed and a plurality of spaced apart and spaced regions. In a preferred embodiment, the hydrophobic material applied to the raised regions of the base sheet comprises hydrophobic fibers in an adjoining nonwoven fabric which has been perforated or provided with slits or other openings, so that the perforations or openings lie on a part of the depressed regions. The elevated hydrophobic regions increase the sensation of dryness and promote the flow of fluid to the lower hydrophilic regions, which comprise the depressed regions exposed from the base sheet. The base sheet is preferably in liquid communication with the underlying absorbent material, more preferably a material cellulose placed by stabilized air or compressed stabilized eraser so that the absorbent material can transmit the fluid out of the base sheet by capillary action. When the soft hydrophobic fibers are deposited on the raised regions, the lining also has a soft cloth-like feel in addition to a dry feel in use.