KR20020025254A - Embossed Liner for Absorbent Article - Google Patents

Abstract

A liner for personal care products is provided having at least one recessed feature embossed feature, preferably two or more layers having an array of such recessed features and facing each other in front of each other. This recessed feature can have a variety of shapes, such as square, diamond, circular or artistic design. However, to get the maximum benefit, they must have the depth and distance needed to form a physical barrier to allow fluid absorption and at the same time reduce the spread of the fluid. The liner may consist of a combination of topsheet material, surge layer and absorbent core embossed together.

Description

Embossed Liner for Absorbent Article

In general, disposable products have a structure that includes a topsheet material (also called a cover sheet), an absorbent core, and a fluid repellent backsheet. In addition, some may have a surge layer or other special layer between the topsheet and the absorbent core. The structure referred to herein as a "liner" is a bonding structure of at least a first layer (top sheet) and a second layer (surge layer) which are located facing each other in front.

Since the topsheet material is a layer in contact with the user's body, the function of the topsheet material is to provide the smoothness needed to make the user feel comfortable while wearing the product, but more importantly, it is able to It must have structural properties that can be quickly absorbed. Rapid absorption is important to reduce the likelihood that fluid will spread out of the perimeter of the absorbent material and into the wearer's garment, causing undesirable leaks or stains. The absorber material has the function of removing fluid absorbed in the topsheet therefrom, preferably distributing and retaining the fluid absorbed in the topsheet through the length, width and thickness of the absorber material. Often, the topsheet material is made of a nonwoven or perforated film. The perforated film was machined using a pattern roll and anvil roll to machine the topsheet film as described in US Pat. No. 5,536,555 to Zelazoski et al. And US Pat. No. 5,704,101 to Majors et al. It can manufacture. Other materials used for this kind of application can be found in US Pat. No. 4,342,314 (assigned to Procter & Gamble Company), which describes vacuum perforated films.

The surge layer is most representatively inserted into contact between the topsheet and other layers, such as the dispensing or retention layer, in intimate and liquid communication with them. The surge layer is typically adjacent to the inward side of the topsheet (away from the wearer's body). Typically, it is desirable to attach the top and / or bottom surfaces of the surge layer to the topsheet and the next layer, respectively, to further enhance liquid delivery.

Absorbent cores used in personal care products are generally made of pulp fibers or pulp fibers mixed with superabsorbent particles. This structure may also include binder fibers for inherent shape integrity.

Difficult challenges in designing products that absorb representative fluids insulated in hygiene products, such as feminine hygiene products and baby hygiene products, are well known in the art. For infant hygiene products, the concern is to absorb urine and feces (BM) feces, while feminine hygiene products are associated with absorbing menstrual blood. Because of the differences in viscosity, density and composition of each fluid, each type of personal care product requires different and complex efforts by the product designer in optimizing the absorption properties of each material used in the final product.

One clue common to all product designers is that all such products do not allow fluid to spread out around the absorber, while at the same time keeping the fluid away from the topsheet and the user's body, reducing the damp sensation and possible skin irritation that a wet topsheet can produce. To have the ability to absorb fluid quickly. For this reason, the structure of any product must be developed so that each component performs well with the others and optimizes their use. This means that the absorbent core must have the ability to rapidly remove the fluid absorbed by the topsheet material as well as the ability to dispense and retain the fluid.

There are many patents that attempt to address the necessary balance between softness and fluid absorption. For example, Aziz, US Pat. No. 4,323,068, describes topsheet materials with increased bosses to improve dryness by isolating surfaces from the user's body. Sanford, US Pat. No. 4,041,951, describes a topsheet material containing multiple recessed areas to isolate the wearer's skin from moisture in the absorber. However, as taught in US Pat. No. 4,323,068, the invention of US Pat. No. 4,041,951 has the disadvantage of not having the structural intact integrity necessary to retain the boss in the material after pressure is applied. Mesek US Pat. No. 3,934,588 describes a nonwoven topsheet made of long and short fibers that provide a sparse area that serves as a preferential passage for fluid absorption. US Patent No. 5,695,595 to Van Hout et al teaches a method of making a material having multiple sparse regions in the form of protrusions that allow vapor and water vapor penetration. US Patent 4,741,941 to Englebert et al describes a nonwoven web with hollow protrusions that can be designed to provide suitable structural properties to allow for rapid suction times. All of the above references show that it is necessary to modify the topsheet structure to provide the necessary absorbency for rapid fluid delivery to the absorbent core while providing separation of the user's body and disposables.

However, there is still a need for a liner for personal care products that can absorb fluid in designated areas and maintain its original appearance integrity while under pressure load, while also retaining its absorbent properties. It is an object of the present invention to provide a novel structure that improves high viscoelastic fluid absorption properties such as menstrual blood or feces (BM) and also maintains intact integrity under pressure.

The present invention relates to an absorbent article for personal hygiene. More specifically, the present invention relates to absorbent systems for disposable products such as women's sanitary napkins with liner with modified surface properties to improve performance, diapers and training pants, wound dressings and bandages, and adult incontinence products. .

The object of the present invention is achieved by a liner that modifies the surface of the porous material to improve the absorption properties of the porous material. An ideal personal care product would be to be able to absorb fluid as quickly as it is delivered to the product so that the fluid does not spread out around the absorber. However, the choice and design of materials used in personal care products is very complicated because of the differences in fluid properties observed between the insults. Thus, the invention disclosed herein addresses the fluid absorption properties of an absorption system that can retain fluids and reduce the likelihood of leakage while also improving surface absorption properties using surface modification.

For example, surface modifications that allow absorption of viscous fluids such as menstrual blood, urine, and BM are one or more concave features embossed onto a composite structure, but the arrangement of such concave features desirable. The composite structure, referred to herein as a liner, is a composite of at least a first layer (topsheet) and a second layer (surge layer) positioned facing the front. The absorber layer can optionally be present as the third layer. All of these components may have more than one layer. Embossing the recessed features on a structure consisting only of the topsheet and the surge layer gave the best results and is therefore preferred.

<Brief Description of Drawings>

1 shows an example of an arrangement of recessed features of the liner of the present invention.

Figure 2 shows another example of the arrangement of the recessed features of the liner of the present invention.

3 is a cross-sectional view of a two-layer composite with concave features.

4-10 show examples of feminine hygiene products with concave features located in various shapes on the product.

11 illustrates a three layer embodiment with recessed features.

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

<Definition>

The term "disposable" encompasses disposal after one use that is not intended to be cleaned and reused.

In the present specification and claims, the term "comprising" is inclusive or unlimited and does not exclude additional elements, compositional components, or method steps that are not listed.

As used herein, the term "nonwoven or nonwoven web" refers to a web having a structure in which the individual fibers or threads are interleaved but not in a way that can be identified as in knitted fabrics. Nonwovens or nonwoven webs have been formed from many methods such as, for example, meltblowing methods, spunbonding methods, and bonded carded web methods. The basis weight of a nonwoven is usually expressed in ounces per square yard (osy) or grams per square meter (gsm), and useful fiber diameters are usually expressed in microns. (Note that when you convert osy to gsm, you multiply osy by 33.91.)

The term "spunbonded fiber" refers to a small diameter fiber formed by extruding molten thermoplastic material as a filament from a plurality of fine capillaries of a spinneret. Such methods are described, for example, in US Pat. No. 4,340,563 to Appel et al. And US Pat. No. 3,692,618 to Dorschner et al., US Pat. Patents 3,338,992 and 3,341,394, Hartman, US Pat. No. 3,502,763, and Dobo et al., US Pat. No. 3,542,615. The fibers are also described in US Pat. No. 5,277,976 to Hogle et al., US Pat. No. 5,466,410 to Hills, and US Pat. No. 5,069,970 to Largman et al., Which describe fibers having an unusual shape. It may have the same shape as described in US Pat. No. 5,057,368.

The term "conjugate fiber" is formed from two or more polymers disposed in discontinuous zones substantially constant across the cross section of the fiber and continuously spanning the length of the fiber. Composite fibers are disclosed in US Pat. No. 5,108,820 to Kaneko et al., US Pat. No. 5,336,552 to Strack et al. And US Pat. No. 5,382,400 to Pike et al.

The term "bonded carded web" is made from staple fibers fed through a coaming or carding unit which separates or separates the staple fibers separately and aligns them in a machine direction to form a generally machine oriented fibrous nonwoven web. Means web. These fibers are purchased in bales and are usually placed in an opener / blend or picker that separates the fibers prior to the carding unit. Once formed, the web is joined by one or more of several known bonding methods. One such bonding method is powder bonding. This method is activated by dispensing the powdery adhesive throughout the web and then typically heating the web and adhesive with hot air.

Another suitable joining method is pattern joining. This method uses heated calender rolls or ultrasonic bonding equipment to bond the fibers together in a conventionally localized bonding pattern, but if necessary, the web can be bonded across its entire surface. One example of a pattern is Hansen Pennings having about 30% bond area and about 200 bonds / in ² , as disclosed in US Pat. No. 3,855,046 to Hansen and Pennings, or " HP "pattern. The HP pattern has a square point or pin engagement area where each pin has a side dimension of 0.965 mm (0.038 inch), a spacing between pins 1.778 mm (0.070 inch), and a mating depth of 0.584 mm (0.023 inch). The resulting pattern has a bonding area of about 29.5%. Another representative point bonding pattern is an extended Hansen Pennings or “EHP” bonding pattern resulting in a 15% bond area. There are many other joining patterns. Another suitable well known bonding method, in particular when using a composite staple fiber, is a breathable bond where hot air is passed through the web to at least partially melt the web component to generate the bond.

The term "airlaying" is a well known method of forming a fibrous nonwoven layer. In the airlaying method, bundles of small fibers having representative lengths in the range of about 3 to about 19 mm are separated and loaded into the feed air and then deposited onto the forming screen, usually with the aid of a vacuum supply. The randomly deposited fibers are then bonded to each other using, for example, hot air or spray adhesives.

The term "coapertured" refers to a composite in which holes (two or more) materials are perforated together to produce a hole that exists throughout the layers. Interfaces created between materials are created by light contact and / or entanglement and / or mutual penetration and / or bonding. This extent depends on the composition and process conditions of the particular material. The pores present throughout the layers are represented by the fibrous / film structure produced through the melting and slight flow of the fibers.

The term "personal hygiene goods" means diapers, training pants, absorbent underpants, adult incontinence products, feminine hygiene products, wound care products such as bandages and other articles.

The term "female hygiene" means a menstrual napkin or pad, tampon and panty liner.

The term "target area" means the area or location on the personal care product where the insult is typically delivered by the wearer.

<Test method>

Rate Block Inhalation Test : This test is used to determine the amount of time a known amount of fluid is drawn into a substance and / or material system. This test apparatus consists of a transparent (preferably acrylic) rate block 10 as shown in FIG. 12 and a timer or stopwatch. Die cut the 102 mm by 102 mm (4 inch by 4 inch) piece of liner material 13 to be tested. (The liners to be tested are specifically described in the specific examples.) The absorber 14 used in this study is described in the "test material" below.

The rate block 10 is 76.2 mm (3 inches) wide, 72.9 mm (2.87 inches) deep (into that page), and protrudes from the body of the rate block 10 at the bottom of the rate block 10. The overall height is 28.6 mm (1.125 inches), including a central area 19 of 0.125 inches (mm) and a width of 22.5 mm (0.886 inches). The rate block 10 has an inner diameter of 4.7 mm (0.186 inch) capillary tube 12 extending obliquely to the central line 16 at an angle of 21.8 ° with the horizontal plane downward from one side 15. The capillary tube 12 can be made by drilling a moderately sized hole from the side 15 of the rate block 10 at an appropriate angle, starting at a point 18.4 mm (0.726 inches) above the bottom of the rate block 10, provided that The starting point of the hole drilled on the side 15 should continue to prevent the test fluid from leaking out of it. The top hole 17 is 7.9 mm (0.312 inches) in diameter and 15.9 mm (0.625 inches) in depth, so it intersects the capillary tube 12. The top hole 17 is perpendicular to the top of the rate block 10 and centered at about 7.1 mm (0.28 inches) from the side surface 15. Top hole 17 is a hole in which funnel 11 is placed. The central hole 18 is for the purpose of observing the progress of the test fluid and is substantially elliptical with respect to the plane of FIG. The central hole 18 is located at the center of the width direction of the late block 10, and the bottom hole width is 8 mm (0.315 inch), and the center to center of the 8 mm (0.315 inch) diameter semicircles forming the end of the ellipse. The length is 38.1 mm (1.50 inches). For ease of observation, the ellipse is enlarged to 10 mm (0.395 inches) wide and 49 mm (1.930 inches) long at 11.2 mm (0.44 inch) up from the bottom of the late block 10. In addition, the top hole 17 and the central hole 18 can also be drilled.

The sample to be tested is placed on the absorber 14 and the rate block 10 is placed on top of the two materials. 2 ml of the artificial menstrual blood fluid prepared below is transferred to the funnel 11 of the test apparatus, and a timer is started. Fluid moves from the funnel 11 into the capillary 12, where the fluid is delivered from the center of the central hole 18 to the material 13 or material system. Observation through the central hole 18 and capillary 12 of the late block 10 stops the timer when all fluid is absorbed into the material or material system. Record the inhalation time of a known amount of test fluid for a given material or material system. This value is a measure of the absorbency of a substance or material system. Short inhalation times indicate systems with greater absorbency. The test is repeated five times for each type of sample and the results are averaged to give one value.

Rewet Test : This test is used to determine the amount of fluid that returns to the topsheet surface when a load is applied. The amount of fluid returning to the surface is called the rewet value. The greater the amount of fluid returning to the surface, the greater the rewet value, while the smaller the amount of fluid returning to the surface, the smaller the rewet value. Small rewet values are associated with the dry matter and therefore with the dry product.

After performing the inhalation test, the material system (topsheet and absorber, or topsheet, surge and absorber) is placed on a closed bag partially filled with saline solution to better distribute the force to the system. Place this bag of fluid on a lab jack. Two absorbent papers are weighed in advance and placed on the material system. Raise the bag, material and blotter paper towards the fixed acrylic plate using a laboratory jack until a total pressure of 1 psi is applied. The pressure is kept constant for 3 minutes, after which the pressure is removed and the blotter paper is weighed again. Record the difference between the weight of the original blotter and the weight of the blotter after the test as the rewet value. The test is repeated five times for each type of sample and the results are averaged to give one value.

Spill Test : A 102 mm × 102 mm (4 inch × 4 inch) material-based piece is placed on an acrylic stage with an inclination angle of 20 °. Using a pipette, inject 1 ml of artificial menstrual blood into the center of the material system at a distance of 5 mm. All fluid flowing out of the material sample is collected in a pre-weighed plastic container and the remainder on the acrylic stage is removed with a pre-weighed absorbent gauze. The outflow value is obtained by summing the amount of fluid absorbed in the gauze and the amount of fluid retained in the plastic container. A smaller outflow value suggests better fluid uptake. The test is repeated five times for each type of sample and the results are averaged to give one value.

Caliper (Thickness) of the material: The Caliper or thickness of the material (in inches) is a Frazier spring model compresometer # 326 bulk tester with a 20.8 foot foot (US 21740 Maryland) Frazier Precision Instrument Corporation, Hagerstown Sweeney Drive 925) is used to measure at three different pressures of 0.05, 0.20 and 0.50 psi. The test is repeated five times for each type of sample and the results are averaged to give one value.

Artificial menstrual blood preparation : The artificial menstrual blood used in the test is to separate the blood into plasma and red blood cells, and to separate the egg whites into thick and thin portions according to US Pat. No. 5,883,231 (where thick is the viscosity after homogenization is 150 sec ^-1 Means that the thick egg white is mixed with plasma and mixed well, and finally red blood cells are added and mixed again to prepare from blood and egg white. A more detailed process is as follows:

Blood (pig depleted pig blood in this example) is separated by centrifugation at 3000 rpm for 30 minutes, but other methods or speeds and times can be used if they are effective. Separate the plasma and store it separately, remove the smokescreen and discard the red blood cells in the pack. It should be noted that blood must be treated in several ways so that it can be treated without clotting. Those skilled in the art are known for various methods such as removing fibrous materials that are susceptible to coagulation by removing fibrin from the blood, adding anticoagulant chemicals, and the like. In order for the blood to be useful, it must not coagulate, and any method can be used as long as it achieves this without damaging plasma and red blood cells.

Separate the giant eggs, discard the yolks and eggshells and leave egg yolks. The egg whites are filtered through a 1000 micron nylon mesh for about 3 minutes, separated into thick and thin portions and discarded. The thick parts of the egg white retained in the mesh are collected, sucked into a 60 cc syringe, then placed on a programmable syringe pump and homogenized by five releases of contents and refill. The degree of homogenization is controlled by a syringe pump speed of about 100 ml / min and a tubing inner diameter of about 0.12 inches. After homogenization, the thick egg white has a viscosity of about 20 centipoise at 150 sec ⁻¹ , which is then placed in a centrifuge and rotated at about 3000 rpm for about 10 minutes to remove debris and bubbles.

After centrifugation, homogenized thick egg whites containing ovamucin are added to a 300 cc FENWALL® transfer pack container using a syringe. 60 cc of pig plasma is then added to this penwall delivery pack container. Remove all bubbles from the Penwall Delivery Pack container and place in a Stomacher laboratory blender, blending at standard (or medium) speed for about 2 minutes in the blender. The penwall delivery pack container is then removed from the blender, 60 cc of porcine erythrocytes are added, and the contents are kneaded and mixed by hand for about 2 minutes or until the contents appear homogeneous. The hematocrit of the final mixture should exhibit an erythrocyte content of about 30% by weight, and in the case of artificial menstrual blood prepared according to this embodiment it should generally be in the range of at least 28 to 32% by weight. The amount of egg white is about 40% by weight.

Ingredients and equipment used to make artificial menstrual blood are readily available. A list of sources of items used is described below, but other sources may of course be used, provided they are nearly equivalent.

Blood (pig): Cocalico Biologicals, Inc .; 449, Limstown, Stevens Road, 567, PA, USA (717) 336-1990

Penwall Delivery Pack Containers (300 mL) (with coupler; Code 4R2014): Baxter Healthcare Corporation (Deerfield Penwall, Illinois, USA 60015)

Harvard Apparatus Programmable Syringe Pump Model Number 55-4143: Harvard apparatus (South Natic, Massachusetts, 01760, USA)

Stormer 400 Laboratory Blender Model No. BA 7021 Serial No. 31968: Seward Medical (London, UK)

1000 micron mesh, Item No. CMN-1000-B: Small Parts, Inc. (Small Parts, Inc .; USA 33014-0650 Miami Lakes Pio Box 4650; 1-800-220-4242)

Hemata Stat-II device (for hematocrit measurement), serial number 1194Z03127: Separation Technology Inc. (Altamonte Springs, Rainer Drive 1096, 32714, USA)

<Detailed Description>

In personal care products, the topsheet material is the layer in contact with the wearer's skin and is therefore the first layer in contact with liquid or other excretion secreted from the wearer. In addition, the topsheet should function to isolate the wearer's skin from the liquid retained in the absorbent structure, be flexible, have a soft feel and be nonirritating.

Various materials can be used to form the body topsheet of the present invention, including perforated plastic films, woven fabrics, nonwoven webs, foams, and the like. Spunbond or meltblown webs of polyolefins, polyesters, polyamides (or other similar fiber forming polymers) filaments, or natural polymers (eg rayon or cotton fibers) and / or synthetic polymers (eg poly Nonwoven materials, including bonded carded webs of propylene or polyester) fibers, have been found to be particularly suitable for use in forming topsheets. For example, the topsheet can be a nonwoven spunbond web of synthetic polypropylene filaments. The nonwoven web has a basis weight in the range of about 10.0 gsm to about 68.0 gsm, more particularly in the range of about 14.0 gsm to about 42.0 gsm, and in bulk or thickness in the range of about 0.13 mm to about 1.0 mm, more particularly about 0.18 mm to about 0.55 mm and may have a density in the range of about 0.025 g / cc to about 0.12 g / cc, more particularly in the range of about 0.068 g / cc to about 0.083 g / cc. In addition, the penetration of such nonwoven webs can be from about 150 Darcy to about 5000 Darcy. The nonwoven web can be surface treated or otherwise processed with a selected amount of surfactant, such as about 0.28% TRITON® X-102 surfactant, to impart the desired level of wettability and hydrophilicity. If surfactants are used, the surfactants may be applied to the web by all conventional methods such as spraying, printing, brush coating and the like. Nonwoven topsheets are usually made from staple fibers, for example by carding, or from long fibers, for example by melt spinning. Such nonwoven webs are often made of polyolefins or polyesters, and may also be composite fibers of polypropylene and polyester or polyethylene in various batches, such as, for example, sheath / core batches, parallel batches, and the like. Mixtures of various fibers can also be used. These materials can be combined in a variety of techniques to provide the required mechanical integrity of the shape. Such means may include thermal bonding or breathing bonding, ultrasonic bonding or adhesive bonding using latex or other adhesives, entanglement using water or needling, and the like. Usually, the topsheet layer is combined with the subsequent layers and backsheet using hot melt or latex adhesive or ultrasonic or mechanical bonding.

The surge layer is most typically inserted into contact between the topsheet and the other layer (distribution or retention layer) in intimate and liquid communication with the layers. The surge layer is usually below the inward (non-exposed) side of the topsheet. In order to further enhance liquid transfer, it may be desirable to attach the top and / or bottom surfaces of the surge layer to the topsheet and the next layer, respectively. Suitable adhesives include, but are not limited to, adhesive bonding (using water based, solvent based and thermally activated adhesives), thermal bonding, ultrasonic bonding, needling and pin drilling, as well as combinations of the foregoing or other suitable attachment methods. Conventional attachment techniques can be utilized. For example, when the surge layer is adhesively bonded to the topsheet, the amount of adhesive added should be sufficient to provide the desired level of bonding that does not unduly limit the liquid flow from the topsheet to the surge layer.

Various foam, woven and nonwoven webs can be used to construct the surge layer. For example, the surge layer may be a nonwoven layer consisting of meltblown or spunbond webs of polyolefin filaments. Such nonwoven layers may include staple or other lengths of composite fibers, bicomponent fibers and homopolymer fibers, and mixtures of these fibers with other types of fibers. The surge layer may also be a bonded carded web or an airlaid web made of natural and / or synthetic fibers. The bonded carded web may be, for example, a powder bonded carded web, an infrared bonded carded web, or a vented bonded carded web. The bonded carded web may optionally comprise a mixture or blend of other fibers, and the fiber length in the selected web may range from about 3 mm to about 60 mm. For example, the surge layer has a basis weight of at least about 17 gsm (about 0.50 osy), a density of at least about 0.010 g / cm 3 (at a pressure of 68.9 Pascals), and a bulk of at least about 1.0 mm (at a pressure of 68.9 Pascals). ), A bulk recovery of at least about 75%, a permeability of from about 500 to about 5000 Darcy, and a surface area per void volume of at least about 20 cm 2 / cm 3. The surge layer may consist of substantially hydrophobic materials, which may optionally be treated with a surfactant or otherwise processed to impart the desired level of wettability and hydrophilicity. The surge layer may generally have a uniform thickness and cross sectional area. Examples of surge materials can be found in US Pat. Nos. 5,879,343 and 5,820,973 to Dodge et al.

In practicing the present invention, it is preferred that there is an arrangement of concave features. These recessed features can have a variety of different shapes such as square, diamond, circular or artistic design. However, to obtain the maximum benefit, the preferred arrangement of recessed features should have the depth and interdental distance needed to allow fluid absorption and at the same time form a physical barrier to contain the fluid to reduce the spread of the fluid. This recess structure is designed in such a way as to provide a temporary reservoir for the fluid so that the topsheet receives the fluid at its own speed and prevents the fluid from spreading. Currently available products do not have this feature and usually cause fluids to spread in an irregular path when using materials with slow inhalation times.

A description of how to produce these results is described herein, but one skilled in the art can suggest other ways of achieving similar results. One way to achieve this type of structure is to use a calendar unit having an embossing roll and a matching arm roll. The materials to be modified are fed simultaneously through the nip of the calender system. Heat and pressure (or ultrasound) permanently emboss the recessed features in the material. This kind of method can be performed off-line or can be incorporated into a production line.

As another feature of the invention, material savings can be achieved by placing a narrow surge layer, particularly in the target area of the product. This means that the surge layer (second layer) should be at least 1/3 narrower than the topsheet layer (first layer).

It is preferred that the materials used to make the structures of the present invention have melt compatibility. The term "melt suitability" means that the materials can be joined together by heat or by heat and pressure. Materials that are not melt compatible can be joined together by entanglement or by other means such as using an adhesive.

When using melt compatible materials, the composite after embossing obtains the high mechanical strength required to maintain the intact integrity of the material in use. In a less suitable embodiment where the materials are not melt compatible, hot melt or latex adhesives can be used as another method to achieve bonding between the layers.

In addition to surfactants, other chemical treating agents may be added to the materials of the present invention. One area of increasing consumer interest is the area of "skin health" treatments, such as, for example, aloe (a substance that many believe positively affect skin health). Other skin health chemicals are also known in the art.

Preferred embodiments of the present invention have an inhalation time of less than 40 seconds, a rewet value of less than 0.35 g, an outflow value of less than 0.50 g, and a caliper loss under pressure of less than 50%.

Test substance and manufacture

Materials used to demonstrate the invention are as follows:

The nonwoven topsheet layer was 3.5 containing 8 wt% titanium dioxide treated with 0.3 wt% of ACOBEL® Base N-62 wettable surfactant (ICI Surfactants, Wilmington, Delaware, USA). Dpf (denier) and 20.3 gsm (0.6 osy) polypropylene fibers (Product Code 41438; Ampacet Corp .; Tartown White Plains Road 660, NY) were spunbonded. This nonwoven fabric has an HP type bonding pattern, but the selection of the bonding pattern is not critical to the function of the present invention.

The surge layer consists of 100 weights of 6 dpf and 23.7 gsm (0.7 osy) polypropylene / polyethylene (PP / PE) sheath-core composite fibers treated with HR6 finish from Chisso Corporation (Fiber Division, Osaka, Japan). Made from% Aeration Bonded Carded Web.

Absorbents were 250 gsm, 90 wt% Coosa 0054 pulp and 10 wt% Kosa (formerly Trevira Inc., and earlier Hoechst-Celanese) T Prepared according to the airlaying method using a -255 fiber binder, and having a density of 0.14 g / cc (unless otherwise specified).

The recess features were applied to the material using a hot press model OK380 (Practix MFG Company; Worth Practics Aldy AC Cantrell 3416, Georgia, USA 30101). The temperature used for the hot plate was 177 ° C. (350 ° F.), dwell time was 15 seconds, and the pressure was 50 Psi.

For the purposes of this test, two sets of plates of male / female configurations with different hole sizes but the same depth were prepared.

Plate 1 had an array of protrusions and holes with each protrusion 4.5 mm in diameter and separated from each hole by 1 mm. Each hole was 0.05 cc in volume and 3 mm in depth. This plate 1 made a material with what is called "concave feature 1".

Plate 2 had an array of protrusions and holes in which each protrusion was 8.5 mm in diameter and separated from each hole by 1 mm. Each hole was 0.18 cc in volume and 3 mm in depth. This plate 2 made a material with what is called "concave feature 2".

The following test matrices were evaluated to demonstrate the fluid absorption characteristics of each material using the inhalation, rewet and outflow tests described earlier.

1-Only non-embossed spunbond nonwoven topsheets are present.

2-only spunbond nonwoven topsheet embossed with recessed feature 1.

3-Only a spunbond nonwoven topsheet embossed with recessed feature 2 is present.

4-A spunbond nonwoven topsheet is present over the surge (surge and topsheet are not embossed).

5-A spunbond nonwoven topsheet is present on the surge (surge and topsheet together are embossed with torsion feature 1).

6-A spunbond nonwoven topsheet is present on the surge (surge and topsheet together are embossed with torsion feature 2).

7-A spunbond nonwoven topsheet is present on the absorbent core (absorbent core and topsheet are embossed together with recessed feature 1).

8-A spunbond nonwoven topsheet is present on the absorbent core (absorbent core and topsheet are embossed together with recessed features 2).

9-A spunbond nonwoven topsheet is present over the absorbent core and surge (absorbent core, surge and topsheet are embossed together as recessed feature 1).

10-Spunbonded nonwoven topsheet over absorbent core and surge (absorbent core, surge and topsheet together embossed with recessed feature 2)

11-A spunbond nonwoven topsheet is present over the absorbent core (absorbent core density = 0.06 g / cc) and the surge (absorbent core, surge and topsheet are embossed together as recessed features 2).

Structures with modified surfaces were created by joining together embossed concave features (if applicable). All materials were tested using the absorbent core described above.

The results obtained from the tests on the materials are shown in Table 1.

matter Inhalation (sec) Rewet (g) Outflow (g) One 55 0.226 0.83 2 47 0.274 0.57 3 47 0.288 0.68 4 49 0.108 0.80 5 28 0.310 0.24 6 14 0.154 0.02

As can be seen from Table 1, fluid uptake was improved by modifying the composite surface. The addition of a surge layer under the topsheet material significantly affected the fluid absorption by greatly reducing the rewet of the topsheet, which is the result of the surge material providing additional volume to separate the absorbent core and the topsheet material. Materials that meet the needs of the present invention have a rewet value of less than 0.40 g, preferably less than 0.35 g.

When the recessed features are added to the composite liner structure (topsheet / surge), the fluid absorption properties are improved, as can be seen by the significant reduction in suction time obtained in the test. Materials that meet the needs of the present invention have an inhalation time of less than 50 seconds, preferably less than 40 seconds.

As can be seen from the above results, the void volume of the recess is directly related to the performance of the material. Urinary feature 1 represents an improvement over single layer spunbond and non-embossed composites, but does not provide the performance benefit of urine feature 2.

Another feature that is improved when using the present invention is the reduction of fluid outflow. The addition of the surge layer in addition to the recessed features can significantly reduce fluid movement in the absorber material and retain a greater amount of fluid within the absorbent structure. This effect cannot be achieved due to the lack of physical barriers by the combination of only the unembossed topsheet and surge material. Materials that meet the needs of the present invention have an outflow of less than 0.60 g, preferably less than 0.50 g.

The following examples illustrate the effect of the addition of concave features on an absorbent system of topsheet and absorber material compared to a system made by embossing the topsheet, surge and absorber material together.

matter Inhalation (sec) Rewet (g) Outflow (g) One 55 0.226 0.83 7 67 0.290 0.63 8 27 0.30 0.53 9 75 0.15 0.60 10 70 0.168 0.58 11 31 0.376 0.36

As can be seen in Table 2, the results show that the high-density (0.14 g / cc) airlaid absorbent core has a slower suction time than the monolayer system. It is believed that this is the result of increased densification of the absorber layer, which can delay fluid absorption into the absorber layer. This effect is also believed to be evident from the increased inhalation time of Examples 9 and 10 with spunbond / surge / absorbent compared to similar Examples 5 and 6 without the absorbent. Nevertheless, in all examples samples with recessed features showed lower outflow values compared to flat systems. One way to improve the observed slow inhalation time is to use low density absorbent cores rather than embossing, as can be seen in the examples using 0.06 g / cc absorbents (faster inhalation times and lower outflow values were obtained in this example). Is to use.

As can be seen from this data, the choice of topsheet, surge and absorber materials plays an important role in the function of the modified topsheet structure. The addition of the recessed features to the three layers described above provides a more stable structure, but depending on the material selected, may impair the absorption function of the system. By adjusting the degree of compression, the type of surfactant, and the concentration, the absorption system can be optimized for the particular application.

A common requirement of this kind of material structure is the ability to maintain its original appearance integrity after use or after product production and packaging. Usually, in order to optimize the space occupied by the product on the shelf, manufacturers can make a decision to apply a high pressure load to the product by folding the product twice or triple. For this reason, evaluations of thickness loss at various pressures have been carried out on several samples.

The results of the evaluation are shown in Table 3 below.

matter Material Caliper (Inch) at 0.05 psi Material caliper under 0.20 psi (inches) Material caliper under 0.50 psi (inches) Caliper difference (%) between 0.05 and 0.5 psi One 0.055 0.049 0.040 -27 2 0.060 0.0354 0.011 -81 3 0.042 0.018 0.014 -66 4 0.075 0.063 0.055 -27 5 0.068 0.060 0.050 -26 6 0.052 0.040 0.026 -50 10 0.098 0.087 0.081 -17

Table 3 shows that addition of the recess features to a single spunbond topsheet results in a reduction in material thickness under load. This effect is the result of having hollow embossing features that easily lose their intrinsic integrity when under load, which reduces the ability to handle fluid absorption. In contrast, a system of topsheets and surges reduces the amount of thickness loss under load.

As can be seen from Table 3, the structure consisting of the topsheet, surge and absorbent core shows the smallest thickness loss of all the samples. This is the result of the structural modification achieved by the method of modifying the airlaid fiber binder, the topsheet and the surge together to form a stable structure. Materials that meet the needs of the present invention have caliper losses of less than 60%, preferably less than 50%, at a pressure of 0.05 to 0.5 Psi.

Referring now to the drawings, it can be seen that many possible shapes of recesses can be present in the product and are included within the spirit and intent of the present invention. 1 and 2 show two layer materials having recesses of various sizes. 3 shows a cross-sectional view of a two-layer material with recesses 1. 4 to 10 show various shapes of feminine hygiene products included in the present invention.

In Fig. 4, the recessed part 1 is arranged around the inside 2 of the product. 5 shows that the recess 1 is placed only in the target area 3 of the product. 6 shows the recess 1 having an artistic or "weird" design arranged in the slightly enlarged target area 3. Fig. 7 shows that the recessed parts 1 are arranged in a lined arrangement without imagination. 8 shows a female pad having recesses 1 arranged in a random pattern. 9 shows a pattern of large and small recesses 1 arranged in one product. Figure 10 shows that very small recesses are arranged in a multi-lined arrangement. Figure 11 shows a three layer material embossed with recesses 1 according to the invention.

The recessed features of the present invention vary in size, depth, shape and distance between recesses. The diameter of the concave features may be 10 cm or less, preferably in the range of 3 to 20 mm, even more preferably about 8 mm. The depth may be 20 mm or less, preferably 1 to 10 mm, even more preferably about 3 mm. The interlevel distance will depend on the desired effect. If the recess is filled closer, it will provide a more effective fluid barrier by reducing the movement of liquid under the liner. In addition, the recess features may be touched such that they are in liquid communication with each other to encourage fluid movement within the liner. However, the recessed features are preferably arranged to have a distance between the edges of the recessed features of about 0.5 to 10 mm depending on their shape.

Embodiments of the invention can be made to have recesses of different shapes and / or sizes. This can only be done for aesthetic reasons or to generate different absorbent properties in various areas of personal care products.

In the case of diapers (for example, diapers exposed to urine and BM), the area of the product most likely to be exposed to urine incorporates a small pattern of recesses and exposure to BM in the product (which may sometimes flow down). Areas that are most likely to be incorporated may incorporate patterns of large recesses. Alternatively, the key can only be applied to the target area or the central area of the product, the most promising result in this case being to reduce spreading. As another location, the recess can only be located around the product, the most promising result in this case is that the fluid does not move out of the product. Combinations of these recessed features can be intended to improve overall product performance and protection. The exact size, location, and the like depend on the fluid being handled and the desired benefit. Another embodiment may include a liner having several layers, such as a topsheet and a surge layer co-perforated. Such cavity drilling can be performed in a pattern such that holes are formed in the bottom of each recess. The location of the various treatment agents, such as surfactants or skin health chemicals, may also vary, for example, placed only on the bottom of each recess or just below the liner. Another way to encourage fluid flow to the recess is to place a fiber in each recess perpendicular to the plane of the material. The fibers allow the fluid to run straight into the recess, thereby reducing the likelihood that liquid will flow out of the product.

As will be appreciated by those skilled in the art, variations and modifications of the invention are contemplated as being within the ability of one skilled in the art. The inventors intend to incorporate such changes and modifications within the scope of the present invention.

Claims (29)

A liner for personal care products comprising a first layer and a second layer each having at least one concave embossed feature and facing each other. The liner of claim 1 having an arrangement of discrete recessed features. 3. The liner of claim 2, wherein the arrangement of the discrete recessed features has fibers in one or more recesses that are perpendicular to the layers. 3. The liner of claim 2, wherein the first layer and the second layer are joined together by a method selected from the group consisting of adhesive means, mechanical means, entanglement means, thermal means and ultrasonic means. 3. The liner of claim 2 wherein the first layer and the second layer are melt compatibility. The liner of claim 2, wherein the first layer is treated with a wettable surfactant. 7. The liner of claim 6, wherein each of the recesses has a bottom and the first layer is treated with a wettable surfactant at the bottom of each of the recesses. The liner of claim 2, wherein the first layer is treated with skin health chemicals. 3. The liner of claim 2, wherein said first layer comprises a nonwoven web of polyolefin fibers. 9. The liner of claim 8, wherein said polyolefin is polypropylene. 3. The liner of claim 2, further comprising a hole in said first layer. The liner of claim 2, wherein the first layer and the second layer are co-perforated. 3. The liner of claim 2, wherein said first layer is made of a perforated film by a method selected from the group consisting of vacuum perforation and mechanical perforation. 3. The liner of claim 2, wherein said second layer comprises a bonded carded web of polyolefin fibers bonded by a method selected from the group consisting of a vent bond, a thermal bond and an adhesive bond. The liner of claim 13, further comprising a composite fiber. 3. The liner of claim 2, wherein said second layer is more wettable than said first layer. The liner of claim 2, wherein the second layer comprises a foam. The liner of claim 2, wherein the recessed feature is located in the target area. The liner of claim 2 wherein the suction value is less than 50 seconds. The liner of claim 2 wherein the rewet value is less than 0.40 g. The liner of claim 2 wherein the outflow value is less than 0.60 g. The liner of claim 2 wherein the caliper loss under pressure is less than 60%. The liner of claim 2, wherein the recessed features are less than 10 cm in diameter. 3. The liner of claim 2 wherein the depth of the recessed features is less than 20 mm. Feminine hygiene pad comprising the fabric of claim 2. A diaper comprising the fabric of claim 2. An adult incontinence article comprising the fabric of claim 2. Suction values of less than 40 seconds, rewetting values of less than 0.35 g, and effluent values of less than 0.50 g, each comprising a first layer and a second layer, each having an array of features embossed into discrete recesses and facing each other in front of each other. And a liner for personal care products having less than 50% pressurized caliper loss. 28. The personal care article of claim 27 wherein said second layer is at least one third narrower than said first layer.