MXPA01009445A - Intake/distribution material for personal care products - Google Patents

Abstract

There is provided an intake/distribution layer for personal care products which is a co-apertured distribution layer and a transfer delay layer between them. The co-apertured distribution and transfer delay layer can serve to store liquid and release it to an absorbent core in a personal care product at a rate at which the core can absorb. This ability to accept irregular and large flow rates makes the layer of this invention particularly well suited for"gush"management. The distribution layer is preferably an airlaid fabric and the transfer delay layer is preferably a spunbond fabric and they are co-apertured using a pin density of preferably about 2.5 pins/cm2.

Description

ABSORPTION MATERIAL / DISTRIBUTION FOR PERSONAL CARE PRODUCTS This application claims the priority of the provisional patent application of the United States of America No. 60 / 127,682 filed on April 3, 1999.

FIELD OF THE INVENTION The present invention relates to a structure in a personal care article such as diapers, training underpants, absorbent underpants, adult incontinence products, bandages and a product for women's hygiene, which accept and distribute the liquid .

BACKGROUND OF THE INVENTION Personal care items include such items as diapers, training underpants, women's hygiene products, such as sanitary napkins, pant liners and plugs, garments and incontinence devices, bandages and the like. The most basic design of such articles typically includes a side-to-body liner, an outer cover and an absorbent core positioned between the body-side liner and the outer cover.

Personal care products must accept fluids quickly and retain them to reduce the possibility of filtration outside the product. The product must be flexible and must have a pleasant sensation on the skin, and even after the discharge of the liquid, it should not be tightened or joined to the user. Unfortunately, even though the previous products have satisfied many of these criteria to varying degrees, a number have not.

It has been found that the continuous flow discharges in women's hygiene products average 1 ml / hour and are not literally continuous or constant, but rather are variable in the rate and can still be paused during a cycle . "Spurt" flow is defined as a sudden heavy flow condition and occurs at flow rates of up to 1 ml / second. During a spurting flow, 1.5 ml of fluid is released from the body on the product. The term "continuous flow" is used to define any flow that falls outside of the definition of gushing flow.

The combination of gushing and continuous flow conditions results in a variable flow. Essentially, the "variable flow" is defined as a continuous flow with occurrences of intermittent gushing. Figure 1 illustrates the differences between the variable flow (diamond) and the continuous flow (square) over the life of a single product where the volume of flow rate is on the Y axis in g / hour and the time is on the X axis in hours.

The answer to this problem is called "variable flow management" and is defined as the ability to absorb and contain a light and continuous flow (1-2 ml / hour) as well as multiple gushes or sudden heavy flow insults (1 ml / second with a total volume of 1-5 ml) during the life of the product.

Many cover materials for women's care, for example, have a conductivity in the z-direction, a low surface energy, a low hollow volume and provide a little separation between the absorbent core and the user due to their structure of two. dimensions. Consequently, these covers result in a slow and incomplete intake, high re-wetting and large surface spots. In addition, typical absorption or acquisition layers are high-volume, low-density void structures, which are ideal for rapid flow absorption, but because these structures typically have low capillarity, the fluid is not suitably desorbed from the roofing material, resulting in a mud and surface moisture. The materials which increase the desorption of the cover are typically high capillarity and high density materials typically, but because these materials have a low hollow volume and a low permeability in the z direction, they inherently retard the absorption of the fluid.

There is still a need to refer to variable flow management by developing an absorption / distribution material which has the necessary hollow volume for rapid absorption and the desired high capillarity for sufficient de-absorption of the cover (eg surface dryness) while that an appropriate capillary structure is maintained for a fluid distribution.

An object of this invention is, therefore, to provide such absorption / distribution material to handle a wide variety of flow conditions including heavy flow discharges or spurt sprouts.

SYNTHESIS OF THE INVENTION The objects of the invention are achieved by a layer of fabric placed by air and a transfer delay layer of spunbonded nonwoven fabric which have been joined by perforation or "coperforation". The result is improved multiple absorption performance and a clean, dry surface cover during use in a women's hygiene product. The technological developments of the material surrounding the handling of the variable flow are focused on achieving an adequate material structure and a balance of properties necessary to achieve this rapid absorption and improved roof desorption, cover staining and improved re-wetting characteristics. . These functional properties are provided through improved material technologies and product construction.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a graph of a variable flow (diamond) and a continuous flow (square) during the life of a single product where the volume of flow rate is on the Y axis in g / hour and the time is over the X axis in hours.

Figure 2 illustrates the trimodal pore structure of the co-perforated material.

Figures 3, 4 and 5 show SEM images of the openings. Figure 3 shows an opening on the air-laid side of the composite. Figure 4 shows an approach of an opening on the air-laid side of the compound and figure 5 shows a perforation of the side joined with spinning of the compound.

Figure 6 compares the pore size distribution of a material placed by air and perforated with a material placed by non-perforated air.

Figure 7 illustrates the detail of a single perforation and the flow through the material.

Figure 8 shows the drilling pattern of bolt to 7.4 bolts / square centimeter using 2.06 mm diameter bolts.

Figure 9 shows the bolt hole pattern at 2.5 bolts / square centimeter with the same bolt diameter.

Figure 10 is a graph of the measured capacity of fabrics placed by air with and without openings where the capacity is on the Y-axis and the cloth density (cc / g) is on the X-axis.

Figure 11 is a plot of a horizontal transmission distance (Y-axis) against time for two perforated and two unperforated air-laid fabrics.

Figure 12 is a graph of the saturation in g / g (Y-axis) against the horizontal transmission distance in inches.

DEFINITIONS "Disposable" includes being discarded after use and not attempting to be washed and reused.

"Hydrophilic" describes fibers or surfaces of the fibers that are wetted by aqueous liquids in contact with the fibers. The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wettability of particular fiber materials can be provided by the Cahn SFA-222 surface force analyzer system or an essentially equivalent system. When measured with this system, fibers having contact angles of less than 90 ° are designated "wettable" or "hydrophilic" while fibers having contact angles equal to or greater than 90 ° are designated "non-wettable" or hydrophobic "Layer" when used in the singular may have the dual meaning of a single element or a plurality of elements.

"Liquid" means a substance without particles and / or the material that flows and can assume the interior shape of a container inside which it is poured or placed.

"Liquid communication" means that the liquid is capable of moving from one layer to another layer, or from one place to another within a layer.

"Conjugated fibers" refers to fibers that have been formed from at least two extruded polymers from separate extruders but which have been spun together to form a fiber. Conjugated fibers are sometimes also referred to as multicomponent or bicomponent fibers. The polymers are usually different from one another even though the conjugated fibers can be monocomponent fibers. The polymers are arranged in different zones placed essentially constant across the cross section of the conjugated fibers and extend continuously along the length of the conjugated fibers. The configuration of such a conjugate fiber can be, for example, a pod / core arrangement where one polymer is surrounded by another or can be a side-by-side arrangement, a cake arrangement or an arrangement of "islands in the sea". . Conjugated fibers are taught in U.S. Patent No. 5,108,820 issued to Kaneko et al., In U.S. Patent Nos. 5,336,552 to Strack et al. And 5,382,400 to Pike et al. For the two component fibers, the polymers may be present in proportions of 75/25, 50/50, 25/75 or any other desired proportions. The fibers may also have shapes such as those described in U.S. Patent Nos. 5,277,976 to Hogle et al., 5,069,970 and 5,057,368 to Largman et al., And incorporated herein by reference in their entirety, which describe fibers. with unconventional shapes.

"Biconstituent fibers" refer to fibers that have been formed from at least two polymers extruded from the same extruder as a mixture. The biconstituent fibers do not have the various polymer components arranged in different zones placed relatively constant across the cross-sectional area of the fiber and the various polymers are usually not continuous along the entire length of the fiber, instead of this, forming fibrils or protofibrils which start or end at random. Biconstituent fibers are sometimes also referred to as multi-constituent fibers. Fibers of this general type are discussed in, for example, the patent of the United States of America No. 5,108,827 granted to Gessner. Bicomponent and biconstituent fibers are also discussed in the textbook "Polymer Blends and Compounds" by John A. Manson and Leslie H. Sperling, copyright 1976 by Plenum Press, a division of Plenum Publishing Corporation of New York, IBSN 0-306-30831-1, pages 273 to 277.

As used herein, the term "machine direction" or MD means the length of a fabric in the direction in which it is produced. The term "cross machine direction" or CD means the width of the fabric, for example, an address generally perpendicular to the machine direction.

As used herein the term "spunbonded fibers" refers to fibers of small diameter, which are formed by extruding molten thermoplastic materials as a filament of a plurality of usually circular and thin capillary vessels, of a spinner with the diameter of the extruded filaments then being rapidly reduced as indicated, for example, in U.S. Patent No. 4,340,563 issued to Appel et al., 3,692,618 issued to Dorschner et al., 3,802,817 granted to Matsuki and others, 3,338,992 and 3,341,394 granted to Kinney, 3,502,763 granted to Hartman and 3,542,615 granted to Dobo and others. Spunbond fibers are generally non-sticky when they are deposited on a collecting surface. Spunbonded fibers are generally continuous and have average diameters (from a sample of at least 10) larger than 7 microns, more particularly between about 10 and 35 microns. The fibers may also have shapes such as those described in U.S. Patent Nos. 5,277,976 issued to Hogle et al., 5,466,410 issued to Hills and 5,069,970 and 5,057,368 issued to Largman et al., Which describe fibers with unconventional shapes. .

As used herein, the term "melt blown fibers" means fibers formed by extruding a molten thermoplastic material through a plurality of usually circular and fine matrix capillary vessels such as melted filaments or filaments into gas streams (e.g. of air), usually hot, and high-speed and converging, which attenuate the filaments of the molten thermoplastic material to reduce its diameter, which can be to a microfiber diameter. Then, the meltblown fibers are carried by the high velocity gas stream and are deposited on a collecting surface to form a meltblown and randomly dispersed fiber fabric. Such a process is described, for example, in United States of America Patent No. 3,849,241 issued to Butin et al. Melt-blown fibers are microfibers which may be continuous or discontinuous, which are generally smaller than 10 microns in average diameter and which are generally sticky when deposited on a collecting surface.

As used herein, the term "coffer" means a process in which at least one meltblown die head is arranged near a conduit through which other materials are added to the fabric as it is being formed. Such other materials can be pulp, superabsorbent or other particles, natural polymer fibers (rayon or cotton fibers) and / or synthetic polymer (for example polypropylene or polyester), for example, wherein the fibers can be a basic length The coform processes are shown in the patents of the United States of America, commonly assigned Nos. 4,818,464 granted to Lau and 4,100,324 granted to Anderson et al. The tissues produced by the coform process are generally mentioned as coform materials.

"Carded and bonded fabric" refers to fabrics that are made of basic fibers that are sent through a combing or carding unit which breaks, separates and aligns the basic fibers in the direction of the machine to form a non-woven fabric. fibrous woven generally oriented in the direction of the machine. The tissue is joined by one or more of several known joining methods.

"Air placement" is a 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 52 millimeters 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, hot air or a sprayed adhesive. Examples of air placement technology can be found in U.S. Patent Nos. 4,494,278, 5,527,171, 3,375,448 and 4,640,810.

The bonding of non-woven fabrics can be achieved by a number of methods; bonding with powder, wherein a powder adhesive is distributed through the fabric and then activated, usually by heating the fabric and the adhesive with hot air; pattern bonding, 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 across its entire surface if so want the bonding through air, wherein the air which is hot enough to soften at least one component of the tissue is directed through the tissue; chemical bonding using, for example, latex adhesives that are deposited on the fabric by means of, for example, spraying; and consolidation by mechanical methods such as drilling and hydroentanglement.

As used herein, "thermal bonding" involves passing a fabric or fabric of fibers that are to be joined between a heated calender roll and an anvil roll. The calendering roller usually has, although not always, a pattern in some way so that the entire fabric is not joined through its entire surface, and the anvil roller is usually flat. As a result of this, various patterns for calendering rolls have been developed for functional as well as aesthetic reasons. An example of a pattern that has points and is the pattern of Hansen and Pennings or "H &P "with about a 30% bond area with about 200 joints per square inch as taught in U.S. Patent No. 3,855,046 issued to Hansen and Pennings. The H &P pattern has bonding areas of bolt or square point where each bolt has a side dimension of 0.965 millimeters, a spacing of 1,778 millimeters between bolts and a joint depth of 0.584 millimeters.The resulting pattern has a joined area of about 29.5%. typical point union is the expanded Hansen and Pennings junction pattern or "EHP" which produces a 15% joint area with a square bolt that has a side dimension of 0.94 millimeters, a bolt spacing of 2,464 millimeters and a depth of 0.991 millimeters Another typical point union pattern designated "714" has square bolt joint areas where each bolt has a side dimension of 0.023 inches, a spacing of or 1,575 mm between the bolts, and a joint depth of 0.838 mm. The resulting pattern has a bound area of about 15%. Yet another common pattern is the star pattern in C, which has a bound area of about 16.9%. The star pattern in C has a bar in the transverse direction or "corduroy" design interrupted by shooting stars. Other common patterns include a diamond pattern with slightly off-center and repetitive diamonds with around a 16% area and a wire weave pattern that looks like the name suggests, like a window grid, with about one area United 19% Typically, the percent of the bonded area varies from about 10% to about 30% of the area of the fabric laminated fabric. As is known in the art, point bonding keeps laminated layers together, as well as imparting integrity to each individual layer by means of bonding the filaments and / or fibers within each layer.

"Coperforation" refers to a material that has been drilled, as well as a drilling process, where two or more materials are drilled together. The openings extend from the upper part to the lower part of the material and are essentially aligned with one another. Coperforation can bind materials either temporarily or permanently together through entanglement, physical union or chemical bonding. It is preferred that the coperforation be carried out at ambient temperatures, not at elevated temperatures.

The "personal care product" means diapers, underpants, absorbent underpants, adult incontinence products, swimwear, bandages and other wound dressings, and products for women's hygiene.

"Women's hygiene products" mean sanitary napkins, pads and plugs.

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 Material Caliber (thickness); The caliber of a material is a measure of the thickness and is measured at 3.5 grams per square centimeter with a volume tester of the Starret type, in units of millimeters.

Density; The density of the materials is calculated by dividing the weight by the unit area of a sample in grams per square meter (gsm) by the material gauge in millimeters (mm) to 3.5 grams per square centimeter and multiplying the result by 0.001 for convert the value to grams per cubic centimeter (g / cc). A total of three samples were evaluated and averaged for the density values.

Horizontal Capillary Transmission Test Procedure: The objective of this test is to determine the horizontal transmission capacity of a material by pulling the fluid through an infinite reservoir.

Equipment Needed: A horizontal transmission pedestal, a menstrual fluid simulator prepared as described below, a ruler, a stopwatch.

Process : Cut the materials to a width of 1 inch (2.54 centimeters) and to a desired length.

Fill the reservoir in a horizontal transmission device with a menstrual fluid simulator.

Place one end of the material in the simulator and leave the rest of the material in the transmission device.

Start timing Measure the distance transmitted in a given time, or the time to transmit a given distance.

Preparation of the Menstrual Fluids Simulator: In order to prepare the fluid, the blood, in this case, defibrinated pig blood, was separated by centrifugation at 3,000 revolutions per minute for 30 minutes, although other methods can be used at speeds and times if they are effective. The plasma was separated and stored separately, the curd lymph coating is removed and discarded and the packed red blood cells are stored separately as well.

The eggs, in this case, the large chicken eggs, were separated, the yolk and the spear were discarded and the egg white was retained. The egg white was separated into the coarse and thin portions by casting the white through a nylon mesh of 1,000 microns for about 3 minutes, and the thinnest part was discarded. Note that alternate mesh sizes may be used and that the time or method may be varied as long as the viscosity is at least that required. The thick part of the egg white was retained on the mesh and was collected and pulled on a syringe of 60 cubic centimeters, which was then placed on a programmable syringe pump and homogenized by ejecting and filling the contents five times. In this example, the amount of homogenization was controlled by the syringe pump rate of about 100 milliliters / minute, and the inner tube diameter of about 0.12 inches. After homogenizing the thick egg white it had a viscosity of about 20 centipoise to 150 seconds "1 and was then placed in the centrifuge and spun to remove debris and air bubbles at around 3,000 revolutions per minute per about 10 minutes, even though any effective method can be used to remove the debris and bubbles.

After centrifugation, the homogenate and coarse egg white, which contained ovamucin was added to a 300 cc Fen all® transfer pack using a syringe. Then 60 cubic centimeters of pig plasma was added to the transfer package. The transfer pack was grasped, all air bubbles were removed, and placed in a Stomacher laboratory mixer where it was mixed at normal (or average) speed for about 2 minutes. The transfer pack was then removed from the mixer, 60 cubic centimeters of red pig blood cells were added, and the contents were mixed by hand kneading for about 2 minutes or until the contents appeared homogeneous. A hematocrit of the final mixture showed a red blood cell content of about 30% and should generally be within the range of 28-32% by weight for the artificial menstrual fluids made according to this example. The amount of egg white was around 40% by weight.

The ingredients and equipment used in the preparation of these artificial menstrual fluids are readily available. Below is a list of the sources for the items used in this example, although of course other sources can be used provided they are approximately equivalent.

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

Fenwall® transfer pack container, 300 milliliters with coupler, sample 4R2014: Baxter Healthcare Corporation, Fenwall Division, Deerfield, IL 60015.

Harvard apparatus programmable syringe pump model No. 55-4143: Harvard Apparatus, South Natick, MA 01760.

Laboratory Mixer Model Stomacher 400 model No. BA 7021, series No. 31968: Seward Medical, London, England, UK. 1,000 micron mesh, item No. CMN-1000 B: Small Parts, Inc., PO Box 4650, Miami Lakes, FL 33014-0650, 1-800-220-4242.

Hemata Stat-II device for measuring hematocrits, series No. 1194Z03127: Separation Technology, Inc., 1096 Rainer Drive, Upper Ont Springs, FL 32714.

DETAILED DESCRIPTION OF THE INVENTION The present invention is an air-laid fabric distribution layer and a spun-bonded non-woven fabric transfer delay layer, which have been joined by perforation. Note that while air-laid and spun-bonded fabrics are preferred in the practice of this invention, other fabrics such as meltblown, coform fabrics and carded and bonded fabrics can be used in the practice of this invention provided that work in an equivalent way. Several foams can also be used, provided their performance is equivalent. The film can also be used, particularly as the transfer delay layer, and is used in some of the examples listed below.

The air-laid distribution layer can be made from a variety of fibers and blends, from fibers including synthetic fibers, natural fibers, including hydroentandered pulp, mechanically and chemically smoothed pulp, basic fibers, burrs, meltblown fibers and spunbond and similar. The fibers in such a fabric can be made of fibers of equal or variable diameters and can be of different shapes, such as pentallobule, trilobular, elliptical, round, etc. The process of placement by air is described above.

The transfer lag layer attached with spinning can also be made from a variety of fibers in a variety of shapes and sizes.

The binders can also be included in the spunbonded and air-laid layers in order to provide mechanical integrity to the fabric. Binders include fibers, liquid media, or other binding media which can be thermally activated. Preferred fibers to be included are those having a relatively low melting point such as polyolefin fibers. The lower melt polymers have the ability to bond the fabric together at the fiber crossing points with the application of heat. further, fibers having at least one component a lower melt polymer, such as conjugated and biconstituent fibers are suitable for the practice of this invention. Fibers having a lower melt polymer are generally referred to as "meltable fibers". By "lower melt polymers" what is meant is those having a glass transition temperature of less than about 175 ° C. Exemplary binder fibers include conjugated fibers of polyolefins and / or polyamides, and liquid adhesives. Two suitable binders are the sheath core conjugate fibers available from KoSA Inc. under the designation T-255 and T-256, although many suitable binder fibers are known to those skilled in the art and are made by manufacturers such as Chisso and Fibervisions LLC of Wilmington, Delaware. A suitable liquid binder is the Kymene® 557 LX binder available from Fibervisions LLC.

Synthetic fibers include those made of polyamides, polyesters, rayon, polyolefins, acrylics, superabsorbents, regenerated cellulose from Lyocel and any other suitable synthetic fibers known to those skilled in the art. Synthetic fibers may also include kosmotropes for degradation of the product.

Many polyolefins are available for fiber production, for example, polyethylenes such as ASPUN® 6811A linear low density polyethylene from Dow Chemical, linear low density polyethylene 2553 and 25355 and high density polyethylene 12350 are such suitable polymers. . The polyethylenes have melt flow rates, respectively, of about 26, 40, 25 and 12. Fiber-forming polypropylenes include ESCORENE® PD3445 polypropylene from Exxon Chemical Company and PF-304 from Montell Chemical Company. Many other polyolefins are commercially available.

Natural fibers include cotton, wool, linen, hemp and wood pulp. The pulps include the standard soft wood fluff class such as Coosa Mills CR-1654, from Coosa, Alabama, the high volume additive formaldehyde free pulp (HBAFF) available from Weyerhaeuser Corporation, of Tacoma, WA, and is one which is a southern softwood pulp fiber crosslinked with an increased moisture modulus, and a chemically crosslinked pulp fiber such as Weyerhaeuser NHB 416. The high volume additive formaldehyde free pulp It has a chemical treatment that fixes in a curling and twisting, in addition to imparting an added wet and dry stiffness and an elasticity to the fiber. Another suitable pulp is the Buckeye HP2 pulp and yet another one is IP Supersoft from International Paper Corporation. Suitable rayon fibers are the 1.5 denier Merge 18453 fibers from Courtaulds Fibers Incorporated of Axis, Alabama.

The air-laid distribution layer and the spin-transfer transfer layer are co-perforated using a mechanical bolt hole. The co-perforation of the distribution and transfer delay layers provides unique characteristics for the management of insults from gushing discharges. A unique material is created with a trimodal pore structure consisting of 1) pores in the volume of the placed by air which are characteristic of the structure placed by original air, 2) large hollow spaces defined by the bolts of the drilling process, and 3) small interfacial pores surrounding the perimeter of the openings. The perforations are typically characterized by an open structure which tapers to a rounded cone-like structure as observed from the air-laid side of the composite. The interfacial pores are smaller than the surrounding pores due to the densification and relocation of the fiber that results from the drilling process.

The transfer delay layer provides a permeability and wettability gradient between the air-laid distribution layer and the underlying retention layer in a product for women's hygiene by avoiding intimate contact between the two layers. Since the transfer delay layer is not wettable and has a low permeability, it promotes the distribution of fluid in the layer placed by air under continuous flow conditions. The wetting of the transfer delay layer can be modified by topical chemical treatments known to those skilled in the art because they affect the hydrophobicity of a material. Some suitable chemicals for the modification of ® wettability are marketed under the brands AHCOVEL, ® ® ® ® Glucopon, Pluronics, Triton and Masil SF-19.

The transfer delay layer also controls the movement of fluid in the Z direction. The transfer delay layer promotes accumulation of liquid or retention in the distribution layer placed by air and then allows the transfer of fluid to the waste when high pressures or high saturation levels occur. It is believed that the fluid preferably does not move inside the openings under conditions of continuous flow. This controlled transfer mechanism results in an elongated spot pattern in the fluff and prevents oversaturation in the discharge area. Under the conditions of spurting flow, the openings in the transfer delay layer allow the fluid to pass immediately through the underlying lint layer.

Additionally, the transfer delay layer allows a visual signal to be incorporated into the shape of the product.

Figure 2 illustrates the trimodal pore structure of the co-perforated material. In Figure 2, three kinds of pores are illustrated. The large pores 1 are located at the point where the fabric was perforated. The smallest pores 2 exist in the fabric placed by original air 4. Yet another class of pores 3 can be found in the area surrounding the point where the fabric was perforated due to the densification of the fabric and the relocation of the fiber during the drilling process.

Figures 3, 4 and 5 show the SEM images of the perforations. Figure 3 shows a perforation on the air-placed side of the composite at an amplification of 2.54 centimeters equal to 1 millimeter. Figure 4 shows a close-up of a perforation on the air-laid side of the composite at a 1-inch amplification equal to 200 microns and Figure 5 exhibits an aperture from the spin-bonding side of the compound at an equal 1-inch amplification to 2 millimeters.

Figure 6 compares the pore size distribution of a material placed by air and perforated with a material placed by non-perforated air. In figure 6 the material placed by non-perforated air is shown by the large dark squares and the material placed by perforated air is shown by the lighter colored diamonds. The pore volume (cc / g) is on the Y axis and the pore radius (micras) is on the X axis. This graph indicates that there is a slight change towards smaller pores with the perforated material. This is due to a slight densification of the material around the openings. The large pores which are created by the openings are not represented in the graph due to their large size. These provide, however, an additional hollow volume for the material.

Figure 7 illustrates the detail of a single opening in relation to the functionality of the absorbent composite. In Figure 7 a discharge (indicated by the arrows) is delivered to the cover 1. The discharge flows through the cover 1 to the co-perforated laminate of the invention where it passes through the layer placed by air 2 either in the opening 3 or through the layer placed by air 2 itself. The discharge can also be distributed along its length to other areas 5 within the layer placed by air 2. Much of the discharge eventually passes through the distribution layer placed by air 2 and the transfer delay layer 6 to the absorbent retention core 4.

The functionality of the coperforated system can be divided into five areas: roof desorption, increased surface area, opening hollow volume, access to the erasure and transmission capacity. Each of these functionality benefits is discussed individually below. 1. De-absorption of Cover The non-perforated areas of the material placed by air maintain a high degree of capillarity after discharge and are very suitable for the desorption of a cover layer. The small pores of the material placed by air provide the capillarity necessary to desorb the typically large pores of a cover, thereby removing a majority of the fluid from the surface of the product. Improved roof desorption results in low deck stain and mud levels. 2. Increased Surface Area Perforated areas of the material placed by air provide an increased surface area for fluid absorption. During the gusts. The fluid contacting the opening can be absorbed in the "x", "y" and "z" directions through the wall of the opening, rather than strictly in the z-direction through the top surface. Therefore, the increased surface area provided by the walls of the openings increases the absorption characteristics of the distribution layer placed by air. Additionally, the apertures increase the overall permeability of the distribution layer placed by air. 3. Hollow Opening Volume The open areas and the hollow volume created by the openings allow the fluid to be internally accumulated in the product before absorption in the material placed by air. This prevents stagnation on the product surface and facilitates the take when the localized saturation of placed by air prohibits an immediate fluid absorption. 4. Access to Retention The openings in the material placed by air provide a direct fluid path to the retention material in the perforated areas. Under flowing conditions, the fluid passes directly through the opening and into the retention material. By providing immediate access to the holding capacity under these conditions, the hollow volume of the placed by air is maintained and the absorption times for multiple discharges are reduced.

. Transmission Capacity Due to the stability of the material placed by air and the high degree of wet integrity, the pores do not fold to an appreciable degree when a product has received a discharge. The stable pore structure allows capillary transmission to transport the fluid out of the discharge area and to other regions of the product. The non-perforated areas of the material placed by air maintain this function and capillary transmission prevents high saturation from occurring in the discharge area. The capillary transmission in combination with the stability of the material allows the hollow volume to be regenerated after a discharge so that additional discharges can be accepted. An adequate absorption / distribution layer horizontally transmits menstrual fluids at a distance of from about 1.2 centimeters to about 15.25 centimeters.

Experiments were carried out to examine the preferred forms of the invention. Three different base weights of the fabrics placed by air were evaluated: 100 grams per square meter, 175 grams per square meter and 250 grams per square meter. Comparisons were made between the three samples of air-laid and perforated fabric and a non-perforated control sample. The fabrics placed by air were made of Weyerhaeuser NB-416 pulp and KoSa binder fiber T-255. The layers bonded with yarn were made of E5D47 polypropylene from Union Carbide Company.

The spun bonded layer was knitted, in this case with an expanded Hansen Pennings (EHP) pattern. The spunbonded and air laid layers produced separately were put together and punched at the annotated pin density. Alternatively, it is believed that the layer placed by air can be produced directly on the spunbonded layer and the two can then be perforated.

The perforation pattern in Figure 8 was initially used and had 7.4 bolts per square centimeter using bolts with a diameter of 2.06 millimeters.

These materials were tested on an absorbent core of pulp fluff using the flat system fluid distribution test. Key measurements included spot size, whether the saturation profile was even or skewed, and the amount of retention and fluid transfer in the layer placed by air. These results are summarized in Table 1.

Table 1: Fluid Distribution Test of Flat-Matrix System of Coperforated Material * The densities reflected above are pre-perforated densities, the densities of the perforated materials are higher.

This test showed a decrease in the length of the stain as well as in fluid retention in the perforated samples, compared to the control, indicating that perforating the fabric placed by air increases the density of the placed by air dramatically because the pin density of the initial drilling pattern (figure 8) was very high. This is most noticeable on samples of high original density and high basis weight. As the density increases, the pore size and hollow volume decrease.

As a result of this sample test, it was determined that the drilling had the potential to impact the performance of the product. In addition, the test was carried out at a bolt density of 2.5 bolts per square centimeter (shown in Figure 9) to minimize the increase in material density after drilling. The bolt diameter remained at 0.081 inches. The fabric density range studied was narrowed to 175 to 200 grams per square meter and the fabric placed by air was co-perforated to a layer of transfer delay of cloth bound with yarn to maintain the distribution functionality.

Tables 2 and 3 show the matrices of additional material that were evaluated. The transfer delay layers were polypropylene fabrics bonded with yarn except where the film is indicated. The transfer delay layers bonded with spinning had a density and a basis weight as indicated. The fabrics bonded with yarn were not treated with surfactants so that they remained naturally non-wettable. The film was a polyethylene film one thousandth of an inch thick.

Table 2: CoPerforated Air Placed Material / Transfer Delay Layer Table 3: CoPerforated Air Placed Material / Transfer Delay Layer Base Weight Density Transfer Delay Layer 175 gsm 0.12g / cc 27 gsm 175 gsm 0.14g / cc 33.9 gsm 200 gsm 0.12g / cc 27 gsm 200 gsm 0.12g / cc 33.9 gsm 200 gsm 0.12g / cc Film 200 gsm 0.14g / cc 27 gsm 200 gsm 0.14 g / cc 33.9 gsm 200 gsm 0.14g / cc Movie The materials described in Tables 2 and 3 represent materials which are believed to have better performance characteristics due to the lower perforated pin density and lower starting weight and / or base density. These materials were tested for capacity, horizontal transmission ability, saturation capacity, fluid splitting characteristics, and triple spurt absorption capacity. Each of these areas is discussed individually below.

Capacity Figure 10 shows the measured capacity for fabrics placed by air with and without perforations where the capacity is on the Y axis and the fabric density (cc / g) on the X axis. In Figure 10, the upper line represents the 175 and 200 grams per square meter, fabrics placed by air not perforated, the middle line a fabric placed by coperforad air of 200 grams per square meter, and the lower line a coperforated tel of 175 grams per square meter. The capacitance decreases with the increased density as expected. The capacity is also reduced slightly by the perforated samples. These data reveal that a cloth placed by perforated air at 200 grams per square meter and 0.14 grams per cubic centimeter has a capacity equivalent to a non-perforated cloth of 175 grams per square meter of 0.14 grams per cubic centimeter.

Horizontal Capillary Transmission - Infinity Depth The horizontal capillary transmission test was completed to evaluate the effect of the drilling process on the horizontal transmission distance. The horizontal transmission distance is important to maintain a visual signal which alerts the user that the product is almost at capacity and must be replaced. Without proper transmission functionality, the visual signal is not present to the desired degree.

The results of the horizontal capillary transmission of the samples placed by low density air of 175 grams per square meter of Table 2 indicate that perforation of the material placed by air reduces the distance of capillary transmission. It is believed that the drilling process creates openings which interrupt the fluid path for transmission and create density gradients around each opening. Perforated materials transmitted between 17 millimeters and 30 millimeters less than non-perforated samples, depending on an original density. There is a bigger difference for the materials which had a higher start density. These results are shown in Figure 11 where the transmission distance in millimeters is shown on the y-axis and the time in minutes on the x-axis. In figure 11, the non-perforated fabric of 33.9 grams per square meter is the highest line, immediately below is the line for the non-perforated fabric of 27 grams per square meter, followed by the perforated fabric of 27 grams per square meter and Perforated fabric of 33.9 grams per square meter.

Figure 11 also indicates that the interruption of the transmission path associated with the perforation has more impact on the horizontal transmission operation than the effect of the density placed by increased air. This indicates that the piercing effect is not a simple effect of densification. The horizontal transmission results indicate that there is a capillary discontinuity in the perforated samples that results in an interruption of the significant transmission path.

In an effort to improve the transmission distance, the fabric samples placed by air of higher density were perforated and their capillary transmission operation was evaluated. Again, the results indicate that the higher density samples are not transmitted as much as in the non-perforated control material. This also showed that the capillary break is a result of the drilling process and indicates that the capillary transmission distance can not be controlled by the density in the perforated materials.

Horizontal Transmission Saturation Capacity To evaluate the level of saturation that results after the horizontal transmission test, the saturated materials were sectioned and weighed. The level of gram saturation per gram was then calculated to determine how the drilling process affects the gram capacity level per global gram of materials. Note that the saturation levels are based on capillary transmission and not on a wetting and draining protocol.

Figure 12 shows the effect of drilling the saturation level for samples placed by low density air of 175 grams per square meter of Table 2. The results indicate that not only decreases the horizontal transmission distance as a result of the process of perforation, but also decreases saturation capacity by transmission. Perforated samples are much less saturated than non-perforated samples regardless of the initial density even when no significant differences were noted between samples having different starting densities. The effect of the perforation appeared to be more dominant than the effect of the initial density. In Figure 12 the saturation in g / g is indicated on the y axis and the transmission distance in inches on the x axis. The uppermost line represents the non-perforated sample of 0.1 g / cc, the lower line of 0.08 g / cc a non-perforated sample, the next line below represents the coperforated sample of 0.08 g / cc, and the lower line represents the co-perforated sample of 0.1 g / cc.

The effect of the perforation on the capillary transmission saturation of materials placed by air of higher density was also evaluated. Again, the perforated samples had gram saturation levels per gram lower than the non-perforated control. Therefore, it appears that the basis weight had a minimal effect on the horizontal transmission distance or the saturation level of the co-perforated samples. The samples of 175 and 200 grams per square meter work similarly and only slight differences were noted between the densities. The global transmission density was the same for the samples of 0.12 g / cc and 0.14 g / cc, but the saturation level of the samples of 0.12 g / cc was higher, being believed that it is attributable to the higher hollow volume of the samples of 0.12 g / cc.

Since the products undergo a variety of flow conditions and pressures in use, the transmission potential under demand absorbency was also studied. The results showed that the materials are evenly saturated throughout their length, indicating that the transmission did not decrease by drilling in a demand-driven absorbance transmission arrangement. It is believed that the stable structure of the fabric placed by air allows the fabric placed by air and perforated to be completely used even when it does not have the continuous capillary fluid paths that are in a fabric placed by air and not perforated.

As a result of this test, it is believed that the bolt density should be between about 1.6 and 6.2 bolts per square centimeter for good performance. The optical stud density will depend on the exact product form in which the laminate of the invention was placed.

Although only a few example embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications to example embodiments are possible without departing materially from the novel teachings and the advantages of this invention. Therefore, all such modifications are intended to be included within the scope of this invention as defined in the following claims. In the claims, the media clauses plus function are intended to cover the structures described herein as carrying out the recited function and not only the structural equivalents but also the equivalent structures. Therefore, even when a nail and a screw may not be equivalent structural in the sense that a nail employs a cylindrical surface to secure the wooden parts together, while a screw employs a helical surface, in the environment of the fastening Wood parts, a screw and a nail can be equivalent structures.

It should also be noted that any patents, applications or publications mentioned herein are incorporated by reference in their entirety.

Claims (17)

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

1. An absorption / distribution layer for personal care products comprising a coperforated distribution layer and a transfer delay layer.

2. The layer as claimed in clause 1, characterized in that said co-perforated materials were drilled with bolts at a density of between about 1.6 and 6.2 bolts per square centimeter.

3. The layer as claimed in clause 2, characterized in that said co-perforated materials were drilled with bolts at a density of about 2.5 bolts per square centimeter.

4. The layer as claimed in clause 1, characterized in that said transfer delay layer is a material selected from the group consisting of films and non-woven fabrics.

5. The layer as claimed in clause 1, characterized in that said distribution layer horizontally transmits the menstrual fluids by a distance of from about 1.2 centimeters to about 15.25 centimeters.

6. The layer as claimed in clause 5, characterized in that said distribution layer has a material selected from the group consisting of an air-laid fabric, bonded and bonded fabrics, coform materials, hydroentangled pulp fabrics and melt blown fabrics .

7. A personal care product selected from the group consisting of diapers, underpants, absorbent underpants, adult incontinence products and products for women's hygiene comprising a layer as claimed in clause 1.

8. The product as claimed in clause 6, characterized in that said product for personal care is a product for the hygiene of women.

9. The product as claimed in clause 6, characterized in that said personal care product is a product for adult incontinence.

10. The product as claimed in clause 6, characterized in that said product for personal care is a diaper.

11. An absorption / distribution layer for personal care products comprising a coperforated distribution layer and a transfer delay layer, wherein said distribution layer comprises a basic polyolefin and is produced by the process of placing by air on said layer of transfer delay, and wherein said layers are perforated at a bolt density of between about 1.6 and 6.2 bolts per square centimeter.

12. The layer as claimed in clause 10, characterized in that said co-perforated materials were drilled with bolts at a density of about 2.5 bolts per square centimeter.

13. The layer as claimed in clause 10, characterized in that said layer placed by air is composed of pulp and thermoplastic fibers.

14. The layer as claimed in clause 10, characterized in that said transfer delay layer comprises polyolefin fiber produced by the spin bonding process.

15. The layer as claimed in clause 13, characterized in that said polyolefin is polypropylene.

16. The layer as claimed in clause 10, characterized in that said transfer delay layer comprises polyolefin film.

17. The layer as claimed in clause 15, characterized in that said polyolefin is polyethylene. SUMMARY An absorption / distribution layer is provided for personal care products which is a coperforated distribution layer and a transfer delay layer between them, the transfer delay and coperforated distribution layer can serve to store the liquid and release it to an absorbent core in a personal care product at a rate at which the core can absorb. The ability to accept large and irregular flow rates towards the layer of this invention particularly well suited for the handling of "bubbles". The distribution layer is preferably a fabric placed by air and the transfer delay layer is preferably a spunbonded fabric and these are co-perforated using a pin density of preferably about 2.5 bolts per square centimeter.