MXPA02002447A

MXPA02002447A - Embossed liner for absorbent article.

Info

Publication number: MXPA02002447A
Application number: MXPA02002447A
Authority: MX
Inventors: Anthony Sasse Philip
Original assignee: Kimberly Clark Co
Priority date: 1999-09-07
Filing date: 2000-08-14
Publication date: 2002-07-30
Also published as: KR20020025254A; WO2001017475A1; AU6904400A; JP2003508156A; BR0013678A; CN1372451A; EP1227778A1; CN1212819C; AU777296B2; ZA200201004B

Abstract

There is provided a liner for personal care products having at least two layers in face to face relation to one another and having at least one concave embossed feature, and preferably an array of such features. These concave features may have different confi gurations such as squares, diamonds, circles or artistic designs. In order to obtain the maximum benefit, however, they should have the necessary depth and distance between each other to allow fluid absorption and at the same time create a physical barrier for the fluid to reduce its spreading. The liner may be made of acombination of a top sheet material, surge layer, and absorbent core embossed together.

Description

ENGRAVED LINING FOR ABSORBENT ARTICLE FIELD OF THE INVENTION The invention relates to absorbent personal care products. More particularly, this relates to an absorbent system for disposable items such as women's care towels, training diapers and underpants, bandages for wound care and bandages, and adult incontinence products, which have a lining with modified surface characteristics to improve performance.

BACKGROUND OF THE INVENTION Disposable products generally have a structure that includes a top sheet material (also referred to as a cover sheet) and an absorbent core and a fluid repellent backing sheet. Some may also have an emergence layer or other specialized layers between the top sheet and the absorbent core. The structure mentioned here as a "liner" is a combination of at least a first layer (upper sheet) and a second layer (emergence layer) which are in a face-to-face relationship. i i? The function of the upper sheet material, since this is the layer in contact with the user's body, is to provide the necessary softness for the user's comfort while carrying the product, but more importantly, it must have the structural characteristics to allow rapid absorbency of fluids from the user's body. Rapid absorbency is important to reduce the possibility of spreading the fluid outside the periphery of the absorbent material and inside the wearer's garments, causing undesirable staining or filtering. The absorbent material has the function of desorbing the fluid from the upper sheet, preferably by distributing it through the length of the absorbent material, the width and its thickness and retaining it. The top sheet materials are often made from perforated films or non-woven fabrics. Perforated films can be made by mechanically piercing a top sheet of film with the use of a pattern roll and an anvil roll as described in U.S. Patent No. 5,536,555 to Zelazoski et al., And in the patent of the United States of America No. 5,704,101 granted to Majors and other. Other material used in this kind of application can be found in U.S. Patent No. 4,342,314 assigned to The Procter & Gamble Company in which a perforated film with vacuum is described. .. " . * .. * .. - rin rfií = fpfii An emergence layer is most typically interposed between and in intimate liquid communication contact with the top sheet and another layer such as a distribution or retention layer. The emergence layer is usually adjacent to the interior surface (outwardly of a user) of the top sheet. It is usually desirable to attach the upper and / or lower surface of the emergence layer to the topsheet and the next layer, respectively, in order to increase the transfer of the liquid.

The absorbent cores used in hygienic personal care products are generally made of pulp fibers or pulp fibers mixed with superabsorbent particles. These structures may include binder fibers for integrity as well.

The difficult challenge in designing products to absorb typical fluids discharged into sanitary products such as women's care products and infant care products is well known in the industry. In the case of infant care products, the concern is to absorb the discharges of urine and fecal (bowel movements) while the feminine care products refer mainly to the menstrual fluids that are going to be absorbed. Due to the differences in viscosity, density and composition of each -BatA -, JIJ fc .. *? ? fluid, each type of product for personal care presents a different and complex challenge for the product designer to optimize the absorption characteristics of each material used in the final product.

A common thread in all product designs is that each of these must have the ability to absorb the fluid quickly, without allowing it to extend outward from the absorbent periphery while at the same time keeping the fluid away from the top sheet and the user's body to reduce the wet feeling and possible skin irritations that a wet top sheet can produce. For these reasons, the structure of any product must be developed in such a way that the component works well with the others to optimize its use. This means that the absorbent core must have the ability to desorb the upper sheet material at a rapid rate while having the ability to distribute and retain the fluid.

There are a number of patents that attempt to refer to the necessary balance between softness and fluid absorption. U.S. Patent No. 4,323,068 issued to Aziz, for example, discloses a top sheet material with high engravings to isolate the user's body surfaces, thereby improving dryness. U.S. Patent No. 4,041,951 issued to Sanford discloses a top sheet material containing you, A? ,, F. i. a multiplicity of depressed areas to isolate the user's skin from the moisture of the absorbent. As taught in U.S. Patent No. 4,323,068, however, the invention of U.S. Patent No. 4,041,951 has the disadvantage of not having the structural integrity necessary to maintain the material protrusions afterwards. that the pressure is applied. U.S. Patent No. 3,934,588 issued to Mesek discloses a nonwoven top sheet made of long, short fibers that provide thin areas to act as preferential conduits for fluid absorption. U.S. Patent No. 5,695,595 issued to Van Hout et al. Teaches a process for forming a material with a plurality of thin regions made in the form of protrusions that permit the permeation of steam and water vapors. U.S. Patent No. 4,741,941 issued to Englebert et al. Describes a non-woven fabric with hollow projections that can be designed to provide the appropriate structure characteristics to allow a quick take-up time. All references described above show the need to modify the top sheet structure to provide separation of the user's body and the disposable article while providing the necessary absorption for rapid fluid transfer to the absorbent core.

There is still a need, however, for a liner for personal care products that will absorb the fluid in the designated regions and that will be able to retain its integrity during pressure loads while still maintaining its absorbency characteristics. It is an object of the present invention to provide a novel structure which improves the fluid absorption characteristics of highly viscoelastic fluids such as menstrual fluids or feces (bowel movements) and which also retains its integrity under pressure conditions.

SYNTHESIS OF THE INVENTION The objects of the invention are achieved by a lining that will increase the absorption characteristics of a porous material by modifying its surface. The ideal personal care product will be one that can absorb the fluid as quickly as it was delivered to the product, without allowing it to extend outside the absorbent periphery. Due to the differences in the fluid characteristics observed between the discharges, however, the choice and design of the materials used in a personal care product are very complicated. The invention described herein, therefore, relates to the fluid absorption characteristics of an absorbent system capable of retaining the fluid and of reducing the possibility of filtering while also being able to .j ^ - g¡M- «- improve their absorbency characteristics by using surface modifications.

Surface modification to absorb viscous fluids, such as menstrual fluids, urine and bowel movements, is at least a concave feature that is recorded on a composite structure, even when an arrangement of such characteristics is preferred. The composite structure, referred to herein as a liner, is a composite of at least one first layer (top sheet) and a second layer (emergence layer) which are in a face-to-face relationship. A third layer of an absorbent layer may optionally be present.

Any of these elements can have more than one layer. The engraving of the concave characteristics on the structures made of a top sheet and an emergence layer alone has shown the best results and is therefore preferred.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows an example of an arrangement of concave characteristics of the lining of the invention.

Figure 2 shows another example of an arrangement of concave characteristics of the lining of the invention.

Figure 3 shows a cross-sectional view of a two-layer composite with concave characteristics.

Figures 4-10 show the examples of a hygiene product for women with concave features located in various product configurations.

Figure 11 shows a three layer incorporation having concave characteristics.

Figure 12 is a schematic diagram of a rate block apparatus suitable for use in determining the fluid intake time of a material or a material system.

DEFINITIONS "Disposable" includes being discarded after a single use and not intended to be washed and reused.

As used herein and in the claims, the term "comprising" is inclusive or open ended and does not exclude additional non-recited elements, component compositions or method steps.

As used herein the term "non-woven fabric or fabric" means a fabric having a structure of individual threads or fibers which are interlocked, but not in an identifiable manner as in a woven fabric. Fabrics or non-woven fabrics have been formed from many processes such as, for example, meltblowing processes, spinning processes and carded and bonded tissue processes. The basis weight of non-woven fabrics is usually expressed in ounces of material per square yard (osy) or grams per square meter (gsm) and useful fiber diameters are usually expressed in microns. (Note that to convert from ounces per square yard to grams per square meter, multiply ounces per square yard by 33.91).

"Spunbonded fibers" refer to small diameter fibers that are formed by extruding the molten thermoplastic material as filaments from a plurality of fine capillary vessels of a spinner member. Such a process is described in, for example, U.S. Patent Nos. 4,340,563 issued to Appel et al., And 3,692,618 issued to Dorschner et al .; in U.S. Patent No. 3,802,817 issued to Matsuki et al., in U.S. Patent Nos. 3,338,992 and 3,341,394 issued to Kinney; in the patent of the United States of America No. 3,502,763 granted to Hartman, and in the patent of the United States of America No. 3,542,615 granted to Dobo and others. The fibers can also have shapes such as those described in U.S. Patent Nos. 5,277,976 to Hogle et al .; 5,466,410 granted to Hills and 5,069,970 and the patent 5,057,368 granted to Largman et al., Which describe fibers with unconventional shapes.

"Conjugated fibers" refer to fibers which have been formed from at least two polymers arranged in different zones placed essentially constant across the cross section of the fibers and which extend continuously along the length of the fibers.

Conjugated fibers are taught in the patents of the States United of America Nos. 5,108,882 granted to Kaneko and others, 5,336,552 granted to Strack and others, and 5,382,400 granted to Pike and others.

The "carded and bonded fabric" refers to fabrics that are made of basic fibers which are sent through a carding or combing unit, which separates or breaks and separates and aligns the basic fibers in the direction of the machine to form a fibrous non-woven fabric generally oriented in the machine direction. Such fibers are usually purchased in bales, which are placed in an opener / mixer, or shredder, which separates the fibers before the carding unit. Once the tissue is formed, it is then joined by one more than several methods .i i known junctions. One such binding method is the binding with powder, wherein a powder adhesive is distributed through the tissue and then activated, usually by heating the fabric and the adhesive with hot air.

Another suitable joining method is a pattern bond where heated calendering rolls or ultrasonic bonding equipment are used to join the fibers together, usually in a localized bonding pattern, even when the fabric can be bonded through its full surface if desired. An example of a pattern is the Hansen Pennings pattern or "HP" with around an area of 30% union with about 200 joints per square inch as taught in United States Patent No. 3,855,046 issued to Hansen and Pennings. The Hansen and Pennings pattern has bolt or square dot joining areas where each bolt has a lateral dimension of 0.965 mm, a separation of 1,778 mm between the bolts, and a joint depth of 0.584 mm. The resulting pattern has a binding area of about 29.5%. Another typical point union pattern is the expanded Hansen Pennings junction pattern or "EHP" which produces a 15% bond area. There are numerous other patterns of union. Another suitable and well-known joining method, particularly when conjugated basic fibers are used, is the bonding through air, where hot air is passed through the fabric, so -teütii. ? , ..., íf.t .. , * ft, l? less by partially melting a component of the fabric to create the joints.

"Air placement" is a well-known process by which a fibrous non-woven layer can be formed. In the air laying process, bunches of small fibers having typical lengths ranging from about 3 to about 19 millimeters (mm) are separated and carried in an air supply and then deposited on a forming grid, usually with the help of a vacuum supply. The randomly deposited fibers are then bonded together using, for example, sprayed adhesive or hot air.

"Coperforation" refers to a composite wherein (at least two) materials are drilled together to create holes which extend through the layers.

An interface is created between the materials which is represented by the light contact and / or the entanglement and / or the interpenetration and / or the connection. The degree or extent of this depends on the composition of the specific materials and the conditions of the process. The perforations which extend through the layers are represented by a film / fibrous type structure created through fusion and some type of fiber. . --- .._! ¿T i. * Yes * The "personal care product" means diapers, underpants, absorbent undergarments, adult incontinence products, women's hygiene products, wound care items such as bandages and other items .

"Women's hygiene products" means sanitary pads or pads, tampons and linings for panties.

The "target area" refers to the area or position on a personal care product where a discharge is normally delivered by a user.

TEST METHODS Rate Block Test: This test is used to determine the time taken for a known amount of fluid inside a material and / or material system. The test apparatus consists of a clear rate block preferably acrylic 10 as shown in Figure 12 and of a timer or time meter. A piece of 102 millimeters by 102 millimeters of lining material 13 to be tested is cut. (The specific linings that are going to be tested are described in the specific examples). The absorbent 14 used for these studies is described under the "test materials" given below.

The rate block 10 is 76.2 millimeters wide and 72.9 millimeters deep (within the page) and has an overall height of 28.6 millimeters which includes a central area 19 on the bottom of the rate block 10 which is also projected from the main body of the rate block 10 and has a height of 3.2 millimeters and a width of 22.5 millimeters. The rate block 10 has a capillarity 12 with an inner diameter of 4.7 millimeters extending diagonally down from one side 15 to the center line 16 at an angle of 21.8 degrees from the horizontal. The capillary vessel 12 can be made by drilling the appropriately dimensioned orifice from the side 15 of the rate block 10 to the appropriate angle starting at a point 18.4 millimeters above the bottom of the rate block 10; always, however, that the starting point of the drilling hole on the side 15 must subsequently be capped so that the test fluid does not escape there. The upper hole 17 has a diameter of 7.9 millimeters and a depth of 15.9 millimeters so that it intersects the capillary vessels 12. The upper orifice 17 is perpendicular to the upper part of the rate block 10 and is centered 7.1 millimeters from the side 15 The upper hole 17 is the perforation in which it is placed in funnel 11. The central hole 18 is for the purpose of viewing the progression of the test fluid and is presently of an oval shape in the plane of figure 12. central hole 18 is centered in the width direction on the rate block 10 and has a lower orifice width of 8 millimeters and a length of 38.1 millimeters from center to center of semicircles of 8 millimeters in diameter constituting the ends of the oval. The oval enlarges in size above 11.2 millimeters from the bottom of the block of rate 10, for ease of view, to a width of 10 millimeters and to a length of 49 millimeters. The upper hole 17 and the central hole 18 can also be made by drilling.

The sample to be tested is placed on the absorbent 14 and the rate block 10 is placed on top of the two materials. Two millimeters of an artificial menstruated fluid as prepared below is delivered to the funnel of the test apparatus 11 and a timing is started. The fluid moves from the funnel 11 to the capillary vessel 12 where it is delivered to the material 13 or to a material system in the center of the central hole 18. The fluid typically extends towards the ends of the central orifice 18 oval. The stopwatch is stopped when all the fluid is absorbed in the material or in the material system as seen through the central hole 18 and from the capillary 12 to the rate block 10. The time taken for a known quantity of the test fluid it is registered for a given material or a material system. This value is a measurement of the absorbency of a material or a system of materials. The lower intake time represents more absorbent systems. Each type of sample is subjected to five test repetitions and the results are averaged to produce a unique value.

Rewet Test: This test is used to determine the amount of fluid that will be returned to the surface of a top sheet when applied to a load. The amount of fluid coming back through the surface is called the rewet value. The more fluid comes to the surface, the greater the rewet value, while if a smaller amount of fluid comes back to the surface the rewet value is lower. The lower rewet values are associated with a drier material and therefore a drier product.

After carrying out the intake test described above, the material system (top sheet and absorbent or superior sheet, emergence and absorbent) is placed in a closed bag which is partially filled with salt water solution in order to distribute it better the forces on the system. The fluid bag is placed on top of a laboratory jack. Two pieces of blotting paper are pre-weighed and placed on top of the material system. The bag, the material system and the paper are raised against a fixed acrylic plate using the laboratory jack until a total of one pound per square inch is applied. The Pressure is kept fixed for 3 minutes, after which the pressure is removed and the blotting paper is weighed again. The difference in weight between the weight of the initial drying paper and its weight after the test is recorded as the rewet value. Each type of sample is subjected to five repetitions of the test and the results are averaged to produce a unique value.

Filtration Test: The 102 millimeter by 102 millimeter material system piece is placed on an acrylic stage that has an inclination angle of 20 °. One milliliter of artificial menstrual fluids are discharged to the center of the material system with the use of a pipette from a distance of 5 millimeters. Any fluid that runs out of the material sample is collected in a pre-weighed plastic container and the residue left on the acrylic stage is removed with the previously weighted absorbent gauze. The value of filtrate or runoff is obtained by adding the fluid absorbed by the gauze and that retained in the plastic container. A lower runoff value implies better fluid absorption. Each type of sample is subjected to five test repetitions and the results are averaged to produce a unique value.

Caliber of material (thickness): The caliber or thickness of a material, in inches, is measured at three pressures íi X? . •. ^ J -t-J l- .. --..., ..-- &> . ... _. . , ",", .a A. _. ..... .- - - «- t - ^ j-! J -» --- different; 0.05, 0.m20 and? .50 pounds per square inch, using a Model 326 compressometer volume tester with a foot of 50.8 millimeters (from Frazier Precision Instrument Corporation, 925 Sweeny Drive, Hagerstown, Maryland 21740). Each type of sample is subjected to five test repetitions and the results are averaged to produce a single value.

Preparation of Artificial Menstrual Fluids: The artificial menstrual fluid used in the test was made according to U.S. Patent No. 5,883,231 of blood and egg white by separating the blood into plasma and red cells and separating the clear in thick and thin parts, where "thick" means having a viscosity after top homogenization of about 20 centipoise to 150 sec "1, combining the coarse egg white with the plasma and thoroughly mixing, and finally adding red cells and again mixing thoroughly, a more detailed procedure is given below.

The blood, in this case, defibrinated pig blood and separated by centrifugation at 3000 revolutions per minute for 30 minutes, even when other methods or speeds and times can be used if this is effective. The plasma is separated and stored separately, the curd lymph is removed and discarded and the red blood cells are stored separately as well. It should be noted that the blood must be treated in some way so that it can be processed without coagulation. Various methods are known to those skilled in the art, such as defibrination of blood to remove fibrous materials that coagulate, the addition of chemicals or anticoagulants and others. The blood must be non-coagulant in order to be useful and any method that accomplishes this without damaging the plasma and red blood cells is acceptable.

The large chicken eggs are separated, the yolk and the calabash are discarded and the egg white is retained. The egg white is separated into thick and thin parts by casting the white through a nylon mesh of 1000 microns for about 3 minutes, and the thinnest part is discarded. The thick part of the egg white, which is retained on the mesh is collected and pulled into a syringe of 60 cubic centimeters which is then placed on a programmable syringe pump and homogenized by ejecting and refilling the contents five times. The amount of homogenization is controlled by the syringe pump rate of about 100 milliliters / minute and the inner tube diameter of about 0.12 inches. After homogenization, the thick egg white has a viscosity of about 20 centipoise to 150 sec "1 and is then placed in the centrifuge and rotated to remove debris and air bubbles at 3000 revolutions per minute around 10 minutes. tit-4 - ». jit - < * - * -JJJ; .-. ,.

After centrifugation, the homogenate and thick egg white, which contains ovamucin, is added to a 300 cubic centimeter FENWAL® transfer pack container using a syringe. 60 cubic centimeters of pig plasma are added to the FENWAL® transfer pack container. The FENWAL® transfer pack container is gripped, all air bubbles are removed and placed in a Stomacher laboratory mixer which is mixed at a normal (or medium) speed for about 2 minutes. The FENWAL® transfer pack container is then removed from the mixer, 60 cubic centimeters of red pig blood cells are added, and the contents are mixed by kneading by hand for about 2 minutes or until the contents appear homogeneous . A hematocrit of the final mixture should show a red blood cell content of about 30 percent by weight and should generally be at least within a range of 28-32 percent by weight for artificial menstrual fluids made in accordance to this example. The amount of egg white is around 40 percent by weight.

The ingredients and equipment used in the preparation of artificial menstrual fluids are readily available. Below is a list of sources for ia-tei-t .- *. a- j..a-fe-t-í, the items used, although of course other sources can be used provided they are approximately equivalent.

Blood (pig): Cocalico Biologicals, Inc., 449 Stevens Rd., Reamstown, PA 17567, (717) 336-1990.

Fenwal® 300 milliliter transfer vessel with coupler, code, 4R2014: Baxter Healthcare Corporation, Fenwal Division, Deerfield, IL 60015.

Programmable Syringe Pump Model Harvard Apparatus No. 55-4143: Harvard Apparatus, South Natick, MA 01760.

Laboratory mixer Stomacher 400 model No.

BA 7021, series No. 31968: Seward Medical, London, England, United Kingdom. 100 micron mesh, item No. CMN-1000-B: Small Parts, Inc., P.O. Box 4650, Miami Lakes, FL 33014-0650, 1- 800-220-4242.

Hemata Stat-II Device for Measuring Blood Cells, Series No. 1194Z03127: Separation Technology, Inc., 1096 Rainer Drive, Altamont Springs, FL 32714. \? & ¿* ~ .. -bli-i-é-iaÉ - i-l-ÉÉ-U-M-? * TfBrJip-ttlÍ--.

DETAILED DESCRIPTION In a personal care product, the top sheet material is the layer against the wearer's skin and thus the first layer in contact with the liquid or other exudate of the wearer. The upper sheet also serves to isolate the user's skin from liquids maintained in an absorbent structure and must be docile, soft and non-irritating.

Various materials can be used to form the topside sheet of the present invention, including perforated plastic films, woven fabrics, non-woven fabrics, foams and the like. Non-woven materials have been found to be particularly suitable for use in the formation of the topsheet, including fabrics bonded with spinning or blown with polyolefin, polyester, polyamide filament (or other type of fiber-forming polymer) melts, or carded and bonded fabrics of natural polymer fibers (eg, rayon or cotton fibers) and / or synthetic polymers (eg, polypropylene or polyester). For example, the top sheet may be a fabric bonded with non-woven yarn of synthetic polypropylene filaments. The non-woven fabric can have a basis weight ranging from about 10.0 grams per square meter (gsm) to about 68.0 grams per square meter, and more particularly from about 14.0 grams per meter square to about 42.0 grams per square meter, a volume or thickness varying from about 0.13 millimeters (mm) to about 0.10 millimeters, and more particularly from about 0.18 millimeters to about 0.55 millimeters, and a density of about between about 0.025 grams per cubic centimeter (g / cc) and about 0.12 grams per cubic centimeter, and more particularly between about 0.068 grams per cubic centimeter and about 0.083 grams per cubic centimeter. Additionally, the permeability of such nonwoven fabric can be from about 150 darcy to about 5000 darcy. The non-woven fabric can be surface treated with a selected amount of surfactant such as about 0.28 percent TRITON® X-102 surfactant or it can be processed in another manner to impart the desired level of wetting and hydrophilicity. If a surfactant is used, it can be applied to the fabric by any conventional means, such as spraying, printing, brush coating and the like. The non-woven upper sheets are usually made of basic fibers, by means of, for example, carded or long fibers by, for example, melt spinning processes. These non-woven fabrics are frequently made of polyolefins or polyesters, and can be conjugated fibers of polypropylene and polyester or polyethylene, for example, put into different arrangements, such as sheath / core, side-by-side, etc. Mixtures of various fibers can also be used. These materials can be linked with different techniques to provide it mechanical integrity needed. Such means include thermal bonding or bonding via air, ultrasonic bonding or adhesive bonding with latex or other adhesives, entanglement with water or by perforation, etc. Usually, the top sheet layer is bonded to the subsequent layers and the backing sheet with latex or hot melt adhesives, or ultrasonic or mechanical bonding.

The emergence layer is more typically interposed between and in intimate liquid communication contact with the topsheet and another layer such as the distribution or retention layer. The emergence layer is usually below the interior (unexposed) surface of the top sheet. To further improve the transfer of the liquid, it is desirable to hold the upper and / or lower surface of the emergence layer to the top sheet and the next layer, respectively. Suitable conventional clamping techniques can be used, including, without limitation, adhesive bonding (water-based, solvent-based and thermally-activated adhesives, thermal bonding, ultrasonic bonding, needle piercing and pin piercing, as well as combinations of the above and other appropriate fastening methods.If, for example, the emergence layer is adhesively bonded to the top sheet, the amount of adhesive added should be sufficient to provide the desired levels of bonding, without restricting tt? ft.F, .f, .S ^ -tMí., 1 ..: excessively the flow of liquid from the upper sheet inside the sprouting layer.

Various foams and woven and non-woven fabrics can be used to build an emergence layer. For example, the emergence layer may be a nonwoven fabric layer composed of a meltblown fabric or bonded with polyolefin filament yarn. Such nonwoven fabric layers may include conjugated, biconstituent and homopolymer fibers of short or other lengths and blends of such fibers with other types of fiber. The emergence layer can also be a carded and bonded fabric or an air-laid fabric composed of natural and / or synthetic fibers. The carded and bonded fabric can be, for example, a carded fabric bonded with powder, a bonded and infrared weave or a carded and bonded fabric through air. The carded and bonded fabrics may optionally include a mixture or combination of different fibers, and the fiber lengths within a selected fabric may vary from about 3 millimeters to about 60 millimeters. The emergence layers of example may have a basis weight of at least about 0.50 ounces per square yard (about 17 grams per square meter), a density of at least about 0.010 grams per cubic centimeter at a pressure of 68.9 pascals, a volume of at least about 1.0 millimeters at a pressure of 68.9 pascals, a volume recovery of at least about 75 percent, a permeability of about IA? .A.A - - .. MAat ... * «-., ... 500 to about 5000 darcy and a surface area per hollow volume of at least about 20 square centimeters per cubic centimeter. The emergence layer may be composed of an essentially hydrophobic material, and the hydrophobic material may optionally be treated with a surfactant or otherwise processed to impart a desired level of wetting and hydrophilicity. The emergence layer can generally have a uniform thickness and a cross-sectional area. Exemplary emergence materials may be found in U.S. Patent Nos. 5,879,343 and 5,820,973 issued to Dodge et al.

It is preferred that an arrangement of concave features be present in the practice of the invention. These concave features may have different configurations such as squares, diamonds, circles or artistic designs. In order to obtain maximum benefit, however, the preferred arrangement of concave features must have the necessary depth and distance between the concavities to allow fluid absorption and at the same time create a physical barrier to contain the fluid and reduce its spreading. These concave structures are designed in such a way as to provide a temporary reservoir for the fluid, allowing the upper sheet to accept the fluid at its own rate without allowing the fluid to spread. Currently available products do not have this feature and usually allow t -... tj.A > ti-a.M _, _, _ «-. .... to the fluid to spread out in an erratic path when using materials that have slower tap times.

Although a description of a process that produces these results is included here, an art expert can promote an alternate form to achieve similar results. A process that achieves this type of structure is done using a calendering unit that has an engraving roller and a matching female roller. The materials that go to 10 to be modified are fed through the pressure point of the calendering system at the same time. The heat and the pressure (or ultrasonic) permanently record the concave characteristics to the materials. This kind of process can be in an offline operation or it can be 15 incorporated in the production line.

In another aspect of the invention, material savings can be achieved by using a narrow emergence layer placed particularly in the product target area. This means that the emergence layer (second) must be at least one third narrower than the top (first) leaf layer.

It is preferred that there be a fusion compatibility 25 of the materials used in the creation of the structures of the invention. By "fusion compatibility" it is meant that the materials can be joined together by only heat or , and through heat and pressure. The materials which are not melt compatible can be joined together by other means, such as entanglement or by the use of adhesives.

When using materials that are compatible by melting, after etching, the composite obtains a high mechanical strength that is desired to maintain the integrity of the material during use. In a less optimal embodiment where the materials are not compatible with fusion, a hot melt or latex adhesive should be used as an alternative to achieve bonding between the layers.

In addition to the surfactants, other chemical treatments may be added to the material of the invention. An area of increasing consumer interest is the area of "skin welfare" type treatments, for example aloe, which is believed by many to positively affect the health of the skin. Other chemicals for the well-being of the skin are known in the art.

The preferred embodiment of the invention has a take value of less than 40 seconds, a rewet value of less than 0.35 grams, a runoff value of less than 0.50 grams and a loss of gauge under pressure of less than 50 percent.

TEST AND PREPARATION MATERIALS The materials used to demonstrate the invention were the following: A nonwoven top sheet layer was made by bonding with 3.5 pff (denier) polypropylene fiber yarn, 0.6 oz. Per square yard (20.3 grams per square meter) containing 8 percent by weight of titanium dioxide (product code 41438 from Ampacet Corporation, 660 White Plains Road, Tarrytown, New York) treated with 0.3 percent by weight of wettable surfactant AHCOVEL® Base N-62 (ICI Surfactants of Wilmington, Delaware, United States of America). This fabric had a Hansen Pennings-type binding pattern even though the chosen bonding pattern is not critical to the operation of the invention.

An emergence layer made from a carded and bonded fabric through 100 percent by weight polypropylene / polyethylene (PP / PE) sheath-core conjugate fibers having 6 denier, 0.7 ounces per square yard (23.7 grams per square meter) with an HR6 finish from Chisso Corporation (Fiber Division) of Osaka, Japan.

An absorbent was made according to the process of placing by air using 250 grams per square meter, 90 percent by weight of Coosa pulp 0054 and 10 percent by weight i .- ^ of Kosa (formerly Trevira Inc., and more formerly Hoechst-Celanese) fiber binder T-255 with a density of 0.14 grams per cubic centimeter unless otherwise specified.

The concave characteristics were applied to the materials with the use of a OK380 hot press from the Practix MFG Company located at 3416 Cantrell, Practix RD AC, Worth, Georgia 30101. The temperature used on the hot plate was 177 ° C with a time of permanence of 15 seconds and 50 pounds per square inch of pressure.

Two sets of plates were made having a male / female arrangement with a different hole size but an equivalent depth for the purpose of this test: • Plate 1 had an arrangement of projections and holes, each projection having a diameter of 4.5 millimeters and being separated from each hole by one millimeter. Each hole had a volume of 0.05 cubic centimeters and a depth of 3 millimeters. This plate 1 produced a material having what is mentioned as characteristic 1. tá? á? ., t-J ... m m- *. . »" - ....

• Plate 2 has an arrangement of projections and holes, each projection has a diameter of 8.5 millimeters and separated from each hole by 1 millimeter. Each hole had a volume of 0.18 cubic centimeters and a depth of 3 millimeters. This plate 2 produced a material having what is referred to as "Feature 2".

EXAMPLES The following test matrix has been evaluated to demonstrate the fluid absorption characteristics of each material using the intake, rewet and runoff test described in the previous section. 1 - . 1 - Top sheet of fabric only joined with yarn, without engraving. 2 - . 2 - Top sheet of fabric only joined with yarn, engraving of the Feature 1. 3 - . 3 - The fabric-only top sheet joined with yarn, engraved from Feature 2. 4 - . 4 - The upper sheet of fabric joined with yarn on emergence, without engraving. 5 - . 5 - the upper sheet of fabric joined with spinning on emergence, the combination recorded using Feature 1. 6 -. 6 - Top sheet of fabric joined with yarn over emergence, the combination recorded using Feature 2. 7 -. 7 - The top sheet of the fabric joined with yarn on absorbent core, the combination recorded using Feature 1. 8 -. 8 - The top sheet of the fabric bonded with yarn on absorbent core, the combination recorded using Feature 2. 9 -. 9 - The top sheet of fabric joined with yarn over emergence and absorbent core, the combination recorded using Feature 1. 10 -. 10 - The top sheet of a fabric joined with spinning on emergence and absorbent core, the combination recorded using Feature 2. eleven - . 11 - The top sheet of the fabric bonded with yarn over emergence and absorbent core, the combination recorded using Feature 2. The absorbent core density of 0.06 grams per cubic centimeter.

Li-, », - ?. i, -í .. «I JÍÍJ ..-. , _. ,, _ .. .. __. . " "^ J j. "J_? .. _ ^ t? t? auttstMaiia & The structures with the modified surface were created by joining together through the recorded concave characteristics (where applicable). All materials were tested using the absorbent core previously described.

The results obtained from the test of the materials are shown in Table 1.

TABLE 1 As seen in Table 1, the absorption of the fluid was increased by modifying the composite surface.

The addition of an emergence layer beneath the sheet material impacted the absorption of fluid by greatly reducing its rewet. This is a result of the additional volume provided by the emergence material giving a separation between the absorbent core and the material -t-t l? ? -t. ta '- .-. - --..- fa¿- & a-S- & of top sheet. The materials satisfying the needs of this invention have a rewet of less than 0.40 grams per square meter and preferably less than 0.35 grams per square meter.

When the concave characteristics are added to the composite linear structure (emergence / top sheet), the fluid absorption characteristics are increased as seen by the significant time reduction of the sample taken in the test. Materials that meet the needs of this invention have a take-up time of less than 50 seconds and preferably less than 40 seconds.

As seen in the results, the hollow volume of the concavity has a direct relationship with the performance of the material. Even though Feature # 1 showed an improvement compared to the one with single layer yarn and with the non-etched compound, it did not offer performance advantages of those of feature # 2.

Another feature that has been improved with this invention is the reduction of fluid runoff. The addition of an emergence layer in addition to the concave characteristics was able to significantly reduce the movement of the fluid in the absorbent material, maintaining a greater amount of it within the periphery of the absorbent structure. This effect may not be obtained by the non-engraved combination of the emergence and top sheet materials alone due to the lack of physical barrier. Materials that meet the needs of this invention have a runoff amount of less than 0.60 grams per square meter and preferably less than 0.50 grams per square meter.

The following examples describe the effect of adding the concave characteristics to an absorbent system composed of the topsheet and the absorbent material as compared to a system comprising the topsheet, absorbent and emergence material recorded together.

TABLE 2 As seen in Table 2, the results show that the absorbent cores placed by air with a higher density (0.14 grams per cubic centimeter) had slower intake times than the single layer system. This is believed to I? * > T -M. »tAJ- *. it is a result of the increased densification of the absorbent layer, which may delay the absorption of the fluid into the absorbent layer. This effect is also believed to be evident in the times of increased uptake of spunbond / sorbent binding Examples 9 and 10 against similar Examples 5 and 6 have no absorbent. Notwithstanding this, in all the examples, the samples with concave characteristics presented lower runoff values in comparison to the flat systems. One way to improve the slower shooting time seen is by using a low density absorbent core before engraving, as seen in the example using 0.06 grams per cubic centimeter of absorbent in which the fastest take-up times and lower runoff values are obtained.

As seen from these data, the choice of top sheet, emergence and absorbent material has an important role in the operation of the modified size sheet structure. Adding the concave feature to the three layers described above provides the most stable structure but may comprise the absorption functionality of the system depending on the chosen material. The absorbent system can be optimized for a particular application by regulating the degree of compaction and the type of surfactant and concentration.

Itt ^ H ^ A common requirement for this kind of material structure is its ability to have its integrity after use, or after the product has been produced and packaged. Usually, to optimize the space occupied by the products on the shelf, the manufacturers have chosen either bi-bent or double-bent products exerting a high-pressure load on the product. For that reason, an evaluation was carried out on the thickness lost at different pressures on the different samples.

The results of that evaluation are located in Table 3.

TABLE 3 Table 3 shows that adding the concave feature to the top sheet joined with spinning | ^^^ «A- ... • only a reduction in the thickness of the material occurs with a loading application. This effect is the result of having a hollow recorded feature that loses its integrity easily when applied to the load, reducing the ability to handle fluid absorption. Contrary to that, having the emergence system and top sheet reduces the amount of thickness loss with the loading application.

As seen in Table 3, the structure made of the top sheet, the emergence and the absorbent core showed the lowest value of the thickness loss of all the samples. This is the result of the modification of structure achieved with the process in which the binders of fiber placed by air, the upper sheet and the emergence are modified together, creating a stable structure. Materials that meet the needs of this invention have a caliper loss of less than 60 percent and preferably less than 50 percent between 0.05 and 0.5 pounds per square inch.

Turning now to the drawings, it can be seen that many configurations of possible concavities may be present in the product and still be within the spirit and intent of the invention. Figures 1 and 2 show a view of a material, in this case, a two-layer material having concavities 1 of different sizes. Figure 3 l - «. iJh» ,. shows a cross-sectional view of a material comprising two layers and having the concavities 1. Figures 4-10 show various configurations for the products for women's hygiene encompassed by the present invention.

In Figure 4, the concavities 1 are arranged around the periphery of the lower part 2 of the product. Figure 5 shows concavities 1 arranged only in the target area 3 of the product. Figure 6 shows the concavities 1 having artistic or "capricious" designs in a slightly expanded target area 3. Figure 7 shows the concavities 1 arranged in a row arrangement per non-imaginative row. Figure 3 shows a pad for the woman who has concavities 1 arranged in a random pattern. Figure 9 shows a pattern of large and small concavities 1 arranged in a single product. Figure 10 shows a row arrangement of concavities where each concavity is quite small. Figure 11 shows a three-layer material which has been etched with the concavities 1 according to the invention.

The concave feature of this invention may vary in size, depth, shape and spacing between the concavities. The diameter of the characteristics can be up to 10 centimeters, preferably in a range of from 3 to 20 millimeters in diameter, and even more preferably 8 j, M. * *? & .- »..». ". »A., 1 millimeter. The depth can be up to 20 millimeters, preferably between 1 and 10 millimeters, and even more preferably around 3 millimeters. The separation between the concavities will depend on the desired effect. The concavities that are packed closer together will provide a more effective fluid barrier by reducing the movement of the liquid beyond the liner. The features can also be touched so that they are in fluid communication with each other and thus facilitate the movement of fluid within the liner. It is preferred, however, that the features, depending on their shape, be arranged to have a separation between the property edges of between about 0.5 and 10 millimeters.

Embodiments of the invention can be prepared with cavities of different sizes and / or shapes. This can be done for purely aesthetic reasons or it can be done to produce different absorbent characteristics in various areas of the personal care product. In the case of a diaper, for example, which is exposed to urine and bowel movements, a pattern of small concavities can be incorporated into the product in the most feasible area to be exposed to urine and a pattern of concavities more large that can be incorporated into the product in the area most likely exposed to bowel movements, which in turn can sometimes be liquid. Alternatively, the concavities can be .. »tA * ^, - ..« ..t .... . . .. .,. . ** * .... TO . at? ? applied in only the target area or the central region of a product with the feasible result being a reduction in the extension. In yet another alternate place, the concavities can be located only on the periphery of a product with the feasible result that the fluid will be prevented from moving out of the product. A combination of such features will be designed to improve the performance and overall protection of the product. The exact size, location, etc., depends on the fluid that is going to be handled and the desired benefit. Still another alternate incorporation may include a liner in which the layers, for example, the upper leaf and emergence are coperforated. Such coperforation can be done in a pattern so that the openings occur at the bottom of each concavity. The placement of various treatments such as surfactants or chemicals for the welfare of the skin can also be varied, placing them, for example, only at the bottom of each concavity or only on the underside of the lining. Still another method of encouraging the flow of fluid inside the concavities is by placing fibers in each concavity perpendicular to the plane of the material. The fibers are able to direct the fluid inside the concavity and reduce the possibility of filtering the liquid from the product.

As will be appreciated by those skilled in the art, changes and variations to the invention are considered as within the capacity of those skilled in the art. lAt-.n-.i, - ^ .. - > -Uk-É? -. the art. Such changes and variations are attempted by the inventors that are within the scope of the invention.

Claims

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

1. A liner for personal care products comprising a first layer and a second layer, said layers being in a face-to-face relationship with one another and having at least one concave engraved feature.

2. The liner as claimed in clause 1, characterized in that it has an arrangement of concave and discrete characteristics.

3. The liner as claimed in clause 2, characterized in that said arrangement of concave and discrete characteristics has fibers in at least one concavity in a direction perpendicular to said layers.

4. The liner as claimed in clause 2, characterized in that said first and second layers are joined together by a method selected from the group consisting of adhesive, mechanical, entangled, thermal and ultrasonic means.

5. The liner as claimed in clause 2, characterized in that said first and second layers are compatible with fusion. x L? *.? ~ i ~ i.a? ¡S¡ ». AL .. * .... . . -,.:,. ^ ^ F "", ». ,? ^ i? & ^ 8 ^ agBi

6. The liner as claimed in clause 2, characterized in that said first layer has been treated with a wettable surfactant.

7. The liner as claimed in clause 6, characterized in that said concavities each have a bottom and said first layer has been treated with a wettable surfactant at the bottom of each of said concavities.

8. The liner as claimed in clause 2, characterized in that said first layer has been treated with a chemical for the well-being of the skin.

9. The liner as claimed in clause 2, characterized in that said first layer comprises a non-woven fabric made of polyolefin fibers.

10. The liner as claimed in clause 8, characterized in that said polyolefin is polypropylene.

11. The liner as claimed in clause 2, further characterized by comprising openings in said layer. n-n * J., .. ^ s ^ ..? ... ...... ^. J »£ ¡s" "> ., ..,? j < lf A ^ áM

12. The liner as claimed in clause 2, characterized in that said first and second layers have been co-perforated.

13. The liner as claimed in clause 2, characterized in that said first layer is made of a perforated film by a method chosen from the group consisting of vacuum perforation and mechanical perforation.

14. The liner as claimed in clause 2, characterized in that said second layer comprises a carded and bonded fabric of polyolefin fibers, joined by a method selected from the group consisting of bonding through air, thermal bonding and adhesive bonding.

15. The liner as claimed in clause 13, further characterized in that it comprises conjugated fibers.

16. The liner as claimed in clause 2, characterized in that the second layer is more wettable than said first layer.

17. The liner as claimed in clause 2, characterized in that said second layer comprises a foam. tjá? ^^^^^^^ - '• i "¿-t"

18. The liner as claimed in clause 2, characterized in that said concave features are located in a target area.

19. The liner as claimed in clause 2, characterized in that it has a take value of less than 50 seconds.

20. The liner as claimed in clause 2, characterized in that it has a rewet value of less than 0.40 grams.

21. The liner as claimed in clause 2, characterized in that it has a runoff value of less than 0.60 grams.

22. The liner as claimed in clause 2, characterized in that it has a gauge loss under pressure of less than 60 percent.

23. The liner as claimed in clause 2, characterized in that said concave characteristics have a diameter of less than 10 centimeters.

24. The liner as claimed in clause 2, characterized in that said concave characteristics have a depth of less than 20 millimeters.

25. A pad for the hygiene of the woman comprising the fabric as claimed in clause 2.

26. A diaper comprising the fabric as claimed in clause 2.

27. A product for adult incontinence comprising the fabric as claimed in clause 2.

28. A liner for personal care products comprising a first layer and a second layer, said layers being in face-to-face relationship to one another and having an arrangement of discrete concave engraved features wherein said liner has a take value of less than 40 seconds, a rewet value of less than 0.35 grams, a filtration value of less than 0.50 grams and a loss of gauge under pressure of less than 50 percent.

29. The personal care product as claimed in clause 27, characterized in that said second layer is at least one third narrower than said first layer. R E U M N A liner is provided for personal care products having at least two layers in a face-to-face relationship with one another and having at least one concave etched feature, and preferably such an arrangement. These concave features may have different configurations such as squares, diamonds, circles or artistic designs. In order to obtain the maximum benefit, however, these must have the necessary depth and distance with each other to allow the absorption of the fluid and at the same time create a physical barrier for the fluid to reduce its extension. The liner can be made from a combination of a top sheet material, an emergence layer and an absorbent core etched together. tdt.at - * »Jt < .ft.A-yift-V-.