KR20000048627A - Concentrating liquid absorption to the center of absorbent articles - Google Patents

Abstract

PURPOSE: An absorbent expanding material is used in an essentially planar absorbent article. The essentially planar absorbent article comprises a topsheet, a backsheet and an essentially planar absorbent core disposed between the topsheet and the backsheet. The absorbent core comprises the absorbent expanding material. CONSTITUTION: Provided is an use of an absorbent expanding material (46) in an absorbent article, such as a sanitary napkin (20) in order to concentrate the absorbed liquid in the central region of the absorbent article. In particular the present invention relates to the use of an absorbent expanding material (46) which upon absorption expands more than the absorbed volume of liquid required in order to provide additional void volume. In addition, the present invention relates to absorbent articles such as baby diapers, adult incontinence products or sanitary articles in which the material of the absorbent core has a better liquid transport capability into the thickness of the article than within the plane of the article.

Description

Use of absorbent expandable materials to center liquid absorption in absorbent products {Concentrating liquid absorption to the center of absorbent articles}

Disposable absorbent products such as sanitary napkins or infant diapers or adult incontinence products or panty liners are well known. Typically these products comprise a wearer facing surface provided by the top sheet, a garment facing surface provided by the back sheet and an absorbent core between the top sheet and the back sheet for absorption of the liquid. The top sheet is liquid permeable such that the liquid is inherently absorbed by the absorbent core. The back sheet may be entirely impermeable to the liquid or gas in a manner that is envisioned to prevent the loss of liquid absorbed on the garment facing side of the absorbent article and thus prevent liquid loss, but breathable or at least vapor permeability may be provided. have.

By the present invention, it has been found to be advantageous because the initial product can be provided in a thin, generally planar form, while the product is expanded to make a volume to store the liquid to be absorbed. Examples of such intumescent materials are absorbent gel materials called superabsorbent or compressed materials which are released when wet from the compressed state. Particularly compressed fibrous materials or sponge structures in regenerated cellulose sponge materials are described, for example, in US Pat. No. 3,736,931, US Pat. No. 3,512,530, EP 293,208, EP 96106724.6 and EP 96106723.8. Has been.

Absorbent gel materials are generally provided in distributed particulate form such that the absorbent core is substantially larger than the area where liquid absorption occurs. Particulate absorbent gel materials are also typically provided with cellulose fibers or tissue to ensure good liquid transport to the particles and to provide additional absorbent capacity.

It is common in the art to include absorbent core means for dispensing liquid to be absorbed in order to better use the entire absorbent structure. It is of course useful that such a liquid distribution layer does not transport liquid to the perimeter of the product where side leakage occurs. Means for preventing such side leaks have been developed in particular in the diaper field and commercialized in the diaper field such as waist blockers or waist bands.

In addition, special designs have been developed to reduce lateral leakage in sanitary napkins, and thus reduce leakage outside the peripheral edge region of the sanitary napkin or pantyliner product. For example, European Patent Publication No. 304,957 discloses a sanitary napkin having a blocking seal across the absorbent core in the transverse direction to prevent spreading of the absorbed liquid along the length of the sanitary napkin so that no leakage occurs at the front and rear ends. Is disclosed.

Side flaps in such products also provide side flaps folded around the edges of the undergarment on which they are worn. The side flap is also separated from the central region of the absorbent structure using a barrier seal to prevent liquid suction into the side flap from the central region of the absorbent article. European Patent Application No. 301,491 also discloses a fluid barrier seal which is envisioned to prevent liquid migration from the central part of the absorbent article to the more circumferential part in the case of the side flap of the sanitary napkin.

Thus, it is a problem at this point that conventional designs of absorbent articles, particularly sanitary napkins, having absorbent structures with good liquid distribution performance may experience potential side edge and / or end edge leakage.

According to the present invention, an absorbent expandable material used in an absorbent structure of a disposable absorbent product maintains the perimeter of the disposable absorbent product so that liquid is less likely to be trapped by internal liquid transport, thereby reducing the likelihood of liquid leakage from the absorbent product. It has been found that this may provide unexpected advantages.

Summary of the Invention

The present invention relates to an absorbent expandable material for use in an essentially planar absorbent article. The essentially planar absorbent article comprises a top sheet, a back sheet and an essentially planar absorbent core disposed between the top sheet and the back sheet. The absorbent core includes an absorbent expandable material.

The present invention relates to an absorbent expandable material used in an absorbent article such as a sanitary napkin to concentrate the absorbed liquid in the central region of the absorbent article. In particular, the present invention relates to an absorbent expandable material which, upon absorption, expands more than the absorbed volume of liquid needed to provide additional void volume. The invention also relates to absorbent articles, such as infant diapers, adult incontinence products or sanitary napkins, in which the material of the absorbent core has the ability to deliver liquids well into the thickness of the product other than in the plane of the product.

1 shows a sanitary napkin according to the invention.

Within the plane of the absorbent core, the central region according to the invention can be defined as the region which initially absorbs liquid through the top sheet under normal conditions of use of such products. From this central region can be distinguished a peripheral region outside the central region in the plane of the absorbent core of the absorbent article. According to the invention, an absorbent expandable material is used to concentrate the absorbed liquid into the central region of the absorbent core. In particular, it is desirable for the absorbent expandable material to expand upon a volume larger than the volume of the absorbed liquid itself upon absorption of the initial liquid, i.e. a volume sufficient to produce additional void volume in the central region of the absorbed core.

Preferably, the absorbent expandable material extends through the central area of the absorbent core so that it can be modified according to the habits of the product user. More preferred is the use of an absorbent core that includes an absorbent expandable material only within the central region so that it does not extend into the peripheral region. As such, the absorbent core and the absorbent expandable material do not extend simultaneously in the plane of the planar absorbent core.

In principle, it is not important in which direction the absorbent expandable material expands. However, the product is formed into a three-dimensional structure using a material that expands from the absorbent core toward the top sheet, thereby allowing the top sheet to rise towards the wearer of such a product and prematurely displacing the liquid disposed on the product after the initial absorption of the liquid. It is desirable to increase the likelihood of blocking.

The absorbent expandable material preferably comprises a regenerated cellulose sponge material and preferably even consists of a regenerated cellulose sponge material. A recycled cellulose sponge material according to the present invention comprising a cutaway portion separating the sponge material from an incremental contiguous increment to ensure that the absorbent expandable material remains intact as a unitary structure while at the same time exhibiting full expansion of the sponge material. Most preferably used. In the most preferred embodiment of the invention, in addition to the regenerated cellulose sponge material, the cutout also preferably has perforations on the surface of the regenerated cellulose sponge material that is closest to the top sheet.

Concentrating the absorbed liquid into the central region of the absorbent core using the absorbent expandable material according to the invention is most appropriately achieved when reducing or eliminating all possible dispensing materials. In a preferred embodiment, the absorbent article in which at least 50%, preferably at least 80% and most preferably at least 95% of the absorbent core material extends out of the central region of the absorbent core is in a direction perpendicular to the essentially planar absorbent core. It has a maximum planar liquid transport capacity in the direction in the essentially planar absorbent core not greater than the maximum vertical liquid transport capacity. In other words, the absorbent core should have better ability to transport to the absorbent core than to spread the liquid as a whole. This is best achieved by not including so-called wicking or distributing layers or by limiting such layers to the central region of the absorbent core.

In a product aspect according to the invention, an absorbent article for absorbing a liquid comprising an upper sheet, a back sheet and an absorbent core according to the above definition concentrates the absorbed liquid in the central region of the absorbent core, including an absorbent expandable material, Such products have a maximum planar liquid transport capacity inwardly of the absorbent core where each material contained in the absorbent core is essentially planar and each material also has a maximum vertical liquid transport capacity in a direction perpendicular to the essentially planar absorbent core. It is characterized by having. Such products also provide a value for the maximum vertical liquid transport capacity of at least 50%, preferably at least 80% and most preferably at least 95% of the volume of material extending in the peripheral region. It is characterized by smallness. Preferably such products are infant diapers or adult incontinence products.

The present invention relates to disposable absorbent articles which exhibit absorbency to body fluids, protection against wearer's garments from contamination, improved physical comfort for the user, and are easy to manufacture and package. Disposable absorbent products are described below with reference to sanitary napkins or hygiene products. As used herein, the term “physiological zone” is worn by a woman adjacent to the vulva region and is intended to absorb and block various body fluids (eg, vaginal discharge, menstrual blood, and / or urine) that are expelled from the body and after use Refers to a product that is intended to be discarded. The disposable absorbent product is substantially flat before use.

The term “substantially flat” herein refers to a product having its main extension in one plane as opposed to being shaped. In a preferred embodiment, the substantially flat article will have an absorbent core that is constant in thickness and not shaped at least in a direction perpendicular to the absorbent core itself. This does not exclude the general curvature of the absorbent core. Those skilled in the art will appreciate the extent to which the product can be deformed from a completely flat shape and the advantages of shaping during use according to the invention.

Thus, sanitary napkins with longitudinal side cuffs, and sanitary napkins with gentle curvature, which can be selectively elasticized, are within the scope of the present invention, provided that their absorbent cores are in a direction perpendicular to the absorbent core itself before use. It must not be shaped as. However, shaped absorbent cores, ie cores with reduced butterflies to the front and / or rear ends of the core, are generally preferred to better fit the butterfly in the vulva region.

The term "connected" or "attached" herein refers to an arrangement in which the first member immediately follows the second member, and an intermediate member in which the first member is connected to the second member so that the first member is connected to the second member. Indirectly followed by a configuration.

One preferred embodiment of sanitary napkin 20 of the present invention is shown in FIG. 1 illustrates a sanitary napkin of the present invention in a flat state prior to use, having a portion of the cut structure to show more clearly the structure of the sanitary napkin 20, and the portion of the sanitary napkin 20 facing or contacting the wearer facing the observer ( 20) is a plan view. As shown in FIG. 1, the sanitary napkin 20 is preferably a liquid permeable top sheet 24, a liquid impermeable back sheet 26 connected to the top sheet 24, and a top sheet 24 and a back sheet ( An absorbent core 28 located in the middle of 26, which includes an inflation layer 46 that expands the sanitary napkin into a three-dimensional structure while worn by the user. The sanitary napkin has two major surfaces, a body contact or facing surface, and a garment facing or contact surface.

The three-dimensional structure of the sanitary napkin 20 is a structure that is at least partially inflated to more closely fit the user's body structure and to better fit its appearance. Particular preference is given to three-dimensional structures having, but not limited to, an inverted convex configuration, which includes an inverted U-shaped or inverted V-shaped, which refers to the structure of a sanitary napkin that is convex over the body facing surface. This arrangement allows the cross-sectional shape of the central portion of the sanitary napkin to fit more closely with the typical wearer's labia.

The upper sheet 24 is soft, soft and non-irritating to the wearer's skin. In addition, the top sheet 24 is liquid permeable to allow easy penetration of liquid through its thickness. Suitable topsheets 24 include woven and nonwoven fabrics; Polymeric materials such as perforated molded thermoplastic films, perforated plastic films, and hydroformed thermoplastic films; Porous foams; Network foams; Networked thermoplastic films; And thermoplastic scrims. Suitable fabrics and nonwovens can be composed of natural fibers (such as wood or cotton fibers), synthetic fibers (such as polymeric fibers such as polyester, polypropylene, or polyethylene fibers), or mixtures of natural and synthetic fibers. have.

Preferred topsheets of absorbent articles of the present invention are described in one or more of the above patents and as "DRI-WEAVE" by The Procter & Gamble Company of Cincinnati, Ohio. It is a commercially available molded film. In a preferred embodiment of the present invention, the exposed body or surface of the molded film top sheet is hydrophilic such that the liquid is transported through the top sheet faster than when the body surface is not hydrophilic so that the fluid flows and is not absorbed by the absorbent core. Reduce the likelihood of spilling out of the top sheet.

The upper sheet 24 of the present invention is preferably inflated to expand the sanitary napkin 20 in a three-dimensional structure upon absorption of body fluids. It is made of a material such that the top sheet is generally oriented longitudinally or laterally, or inherently elongated by causing it to be crimped or folded in a combination of the two directions.

The back sheet 26 is substantially liquid (eg, menstrual blood and / or urine) impermeable unlike the top sheet. The function of the back sheet 26 is to prevent any feces that may exit the absorbent core 28 from contacting or wetting the wearer's undergarment. The backsheet 26 may thus comprise a woven or nonwoven fabric, a polymeric film such as a thermoplastic film such as polyethylene or polypropylene, or a composite material such as a film-coated nonwoven. Preferably, the back sheet is a polyethylene film embossed and / or matt finished to give a fabric-like feel. Preferably, the back sheet also provides the absorbent article with at least water vapor permeability, preferably air permeability, but which does not impair the main function of the back sheet. The back sheet can be a laminated material such as a microporous film and a perforated molded film. In some cases, breathability may be limited around the back sheet or traverse the entire back sheet.

In a preferred embodiment of the invention, the sanitary napkin 20 is also equipped with panty fixing means. Generally at least a portion of the outer surface of the back sheet 26 is coated with an adhesive to form a panty fastening adhesive.

Panty fastening adhesives are generally covered with removable release paper or film to prevent the adhesive from drying out or sticking to surfaces other than panties.

In a preferred embodiment, the absorbent core 28 comprises an expandable layer 46 and separate substantially unexpanded absorbent members 44 that are connected together to face each other, wherein the expandable layer 46 has a top sheet ( 24 and the absorbent member 44.

Absorbent member 44 and expandable layer 46 may be connected in an appropriate manner to form absorbent core 28. Suitable methods include, but are not limited to, the method of joining the absorbent member 44 and the expansion layer 46 to the adhesive by spray-pasting, or applying a line or point between them with the adhesive. Alternatively, or additionally, interlayer bonding can be accomplished by fiber entanglement or multiple discrete fusion bonds.

Optionally, the inflation layer 46 may constitute the entire absorbent core 28.

The absorbent capacity of the absorbent core 28 should be compatible with the intended body fluid load on the absorbent article, including the volume created by the expansion of the expandable layer.

In some cases, as shown in FIG. 1, the substantially non-expandable absorbent member 44 of the absorbent core 28 is generally compressible and elastic, non-irritating to the wearer's skin, and can absorb and contain body fluids. It may be an absorption means of. The absorbent member 44 can be made from a wide variety of liquid absorbent materials commonly used in the field of disposable absorbent articles.

In the embodiment shown in FIG. 1, the absorbent member 44 of the absorbent core 28 itself comprises an absorbent stack of heat-bonded airlaid materials folded twice in the longitudinal direction and particles of absorbent gel material therebetween. do.

The absorbent core 28 includes an inflation layer 46 for inflating the sanitary napkin 20 while the sanitary napkin 20 is worn to concentrate the absorbed liquid of the product in the central region. In a preferred embodiment, the swelling is provided by swelling of the swelling layer 46 and is activated while worn by the initial absorption of body fluids. Expansion layer 46 refers to a fibrous material or any material capable of expanding a compressed cell structure or, in other words, a material that is initially exposed by liquid and then returned to a reduced volume state relative to its volume. This includes, but is not limited to, fibrous substrates comprising superabsorbent fibers in particular, fibers coated with absorbent gel material suspended in a matrix of compressive elastic fibers, compressed foams or sponges from natural or artificial sources, or compressed pit moss It includes.

Particulate absorbent gel materials or other swelling materials that form superabsorbent unbreakable but stable fibrous structures, such as bonded polymeric networks or scrims, may also be used in accordance with the present invention.

After absorption and subsequent swelling of body fluids, the expansion layer 46 material should remain soft, flexible, conformable and elastic. The ability to fit the body provides intimate contact with the exposed vulva of the female user. This allows the fluid to be better transported from the user to the expansion layer 46. While this property of the expansion layer 46 allows for improved matching, this also allows the product to concentrate the absorbed liquid at its center.

Preferably, the inflation layer 46 forms at least a portion of the surface of the top sheet opposite the absorbent core 28. In the embodiment described in FIG. 1, the inflation layer 46 is positioned in an opposing relationship over the absorbent member 44.

The expandable layer 46 of the absorbent core 28 has a body facing surface oriented towards the top sheet and a garment facing surface opposite thereto and is preferably enclosed in at least one of the body facing surface or the garment facing surface. Or an incision 48 that can be arranged in an intersecting line of an open arrangement.

The term "incision", which is incorporated herein by reference, refers to an incision on the surface of a layer; The incision includes the total thickness of the layer, but it is not possible to divide the layer into two or more separate parts.

The closed arrangement of intersecting lines is an arrangement in which the lines are arranged in a mesh and completely interconnected with each other, as described in FIG. 1. In an open arrangement of intersecting lines, the lines intersect to form closed contours (eg, square, circular, hexagonal contours) but do not form interconnected networks.

The incision may preferably have a depth in the dry, unexpanded state, in the range 50-95% of the thickness of the expanded layer 46, more preferably 70-90%, and the pitch of the array is 0.5-10 mm. .

As shown in FIG. 1, the incision 48 preferably cuts off the body facing surface of the inflatable layer 46 with a number of small members 50 connected to each other at the bottom, ie, at the garment facing surface of the inflatable layer 46. They are arranged in a closed array of intersecting lines for dividing. Upon activation by the absorbed fluid, each member 50 can swell without being constrained by the surrounding zone of the expansion layer 46 not reached by the fluid. This allows the localization zone of the expansion layer 46 to swell for much longer when absorbed when the first drop of fluid is received by the expansion layer 46. It further supports additional void volume formation to concentrate the absorbed liquid in the center.

The expansion layer 46 of the absorbent core 28 further includes a perforation 49 in at least one of the body facing surface or the garment facing surface. The perforations extend at least 30% of the thickness of the expanded layer 46, preferably at least 50%, more preferably at least 80%. Perforations with different depths distributed over the various expansion layer 46 bands are also possible. Perforation 49 may also extend through the entire thickness of expansion layer 46.

The total area of the perforations 49 is from 5 to 80%, preferably from 10 to 65%, more preferably from 15 to 45 of the surface area of the body facing surface or the garment facing surface of the expanded layer 46 in which they are constructed. Occupies% This corresponds to the open area of the surface.

Perforations 49 may be disposed in the inflation layer 46 in a random or repeating pattern. The preferred pattern for the perforations 49 may be a rectangular array pattern, as shown in FIG. If the perforations and incisions are preferably present on the same surface of the inflation layer 46, they may for example be arranged in such a way that the perforations intersect the incisions. Preferably, each small member 50 comprises a perforation 49 as described in FIG. 1.

The combined effect of the incision 48 and the perforation 49 provided on the body facing surface of the inflation layer 46 is that the release of the first fluid is quickly captured in the perforation 49. The perforations then provide a large pore space for initial fluid capture and a large surface area usable for fluid absorption.

Upon absorption of the first amount of bodily fluid, the small member 50 of the inflation layer 46 can swell substantially independently from, and without being bound by, the surrounding member not reached by the fluid. Thus, the zone of the expansion layer 46 that initially receives the fluid can be better swollen unless it is divided within the members 50 separated from each other by the cutout 48.

In a preferred embodiment of the invention, the expansion layer 46 comprises a sheet of compressed regenerated cellulose sponge.

Preferably, the regenerated cellulose sponges that make up the expansion layer 46 are materials well known to those skilled in the art. That is, examples of suitable materials are disclosed in US Pat. No. 3,954,493 and French Patent Application No. 2,203,827 and European Patent Publication No. 0 293 208. Regenerated cellulose sponges are sponges of materials that contain a cellulose backbone. Examples of such sponges include, in addition to a sponge composed of cellulose itself, a sponge composed of a cellulose derivative as a viscous cellulose ether and a cellulose ester, and a sponge composed of a mixture of these materials.

By way of example only, a regenerative compression sponge can be prepared from a mixture of reinforcing fibers and a viscous solution of a porosogenic compound such as sodium sulfate hexahydrate or other alkali metal salts with crystals of high content of crystallized water, the final pore unit being a salt The viscous solution is extruded through an extrusion die of the desired section and then solidified, after which the material is regenerated, washed with water, removed salts and other possible soluble compounds, dried and, if necessary, the desired density. Compress until.

Compressed regenerated cellulose sponges have a network structure containing bubbles produced by the removal of sodium sulfate crystals.

Compressed regenerated cellulose sponge materials are available in various forms such as layers or sheets of different density, thickness and basis weight, and the dry density values for the compressed materials used in the present invention are from 0.1 to 1 g / cc, while the thickness is It may range from 0.2 to 5 mm.

The swelling upon liquid absorption of the compressed regenerated cellulose sponge material forming the expanded layer 46 occurs substantially in the compression direction and then restores the pore size of the regenerated sponge before compression. It can also create a void volume that does not collapse upon wetting, allowing for the rapid capture of additional release of fluid.

In the embodiment shown in FIG. 1, the sanitary napkin 20 consists of an expandable layer 46 made of a sheet of compressed regenerated cellulose sponge, and an absorbent member 44.

Compressed regenerated cellulose sponges have a dry density of 0.5 g / cc and a thickness of 2 mm. The absorbent member 44 of the absorbent core 28 is 207 mm long and 64 mm butterfly, and the expanded layer 46 of the compressed regenerated cellulose sponge is 125 mm long and 30 mm butterfly. The incisions 48 are aligned on the body facing surface of the inflation layer 46 in a quadrangular arrangement with a 4 mm pitch defining a small rectangular member 50. The depth of the incision is about 1.7 mm. The inflation layer 46 comprises a circular perforation 49 made through the total thickness of the layer 46 and having a diameter of 2 mm constant through the thickness of the layer. The perforations 49 are aligned with a 20% created opening area in such a way that each small member 50 comprises a single perforation 49. Suitable sheets of compression regenerated cellulose sponges are those made by Spontex France.

Compressed regenerated cellulose sponge sheet 46 is capable of rapidly absorbing body fluids as its volume increases by about 2 to 20 times, typically 5 to 15 times, the volume upon compression. The volume increase substantially corresponds to the swelling in the compression direction.

The amount of absorbed liquid concentrated in the central region of the product can be further optimized depending on the liquid transport capacity of the material used in the absorbent core construction. "Liquid transport force" according to the invention is the speed of mass transport in the direction of the material. This can be quantified by measuring the amount and wicking rate in the material. It is important to consider both the transport rate and the amount transported so that the liquid transport value indicates the amount of liquid transported per time increase through the defined cross section of the material. This can be measured for example against gravity or horizontal wicking force.

The absolute capacity of liquid transport is important because it only provides a product with the desired absorption rate. This can be readily assessed by those skilled in the art when compared to conventional materials for absorption or attempting of the product.

However, according to the present invention the concern is the relative capacity of liquid transport through the thickness of the material versus the liquid transport capacity in the plane of the material. To optimize the concentration of liquid in the center of the product, the liquid transport capacity through the product must be greater than or equal to the liquid transport capacity along the plane of the product.

If at least 50%, preferably at least 80% and most preferably at least 95% of the volume of the material used in the structure of the absorbent core is satisfied, the concentration of liquid absorbed in the center of the product is improved. Particularly good results can be achieved when the combined liquid transport capacity of all materials passing through the product into the absorbent core is 5%, preferably 10% or more above the maximum liquid transport capacity in any direction in the plane of the absorbent product.

Liquid transport capacity can be measured using water or isotonic sodium chloride solution. The same liquid may be used as the liquid for absorption, but is not usually necessary to provide a relative measure of the liquid transport capacity in various directions within the material. Preferred embodiments of the present invention provide that the expanded material has an absorbent core structure with anisotropic liquid transport capability (in a differential transport direction perpendicular to the plane of the absorbent core) while other materials used in the absorbent core are essentially isotropic. Has the ability to transport liquids.

The liquid transport capacity of the individual components of the absorbent core need not be an intrinsic material property that is not affected. Means commonly used in the art to influence the liquid transport capacity are, for example, compression, thermal barrier formation, bonding or impregnation of material, for example. For example, the absorbent member 44 may have a liquid transport delay capability along the curve of the central region of the absorbent member 44 so that the concentration of the liquid absorbed in the central region is improved.

Optionally, the sanitary napkin may have a flap that extends laterally from the side edge of the absorbent core. The flap is configured such that the flap is disposed between the wearer's panties and the wearer's crotch over the edge of the wearer's panties in the crotch region. The flap properly positions the sanitary napkin in the panty to prevent contamination of the wearer's body and panties.

The flap consists of a variety of materials and follows a variety of designs well known in the art. Preferred flaps suitable or applicable to the sanitary napkin 20 of the present invention are described in US Pat. Nos. 4,687,478 issued to Van Tilburg on August 18, 1987 and half til on May 20, 1986. US Patent No. 4,589,876 to Bug.

Optionally, the sanitary napkin can include components that naturally wrap around the sides of the wearer's panties.

Features or features common to diaper or incontinence products are well known in the art of absorbent products and can be included in such products. This includes, without limitation, elastics, closure mechanisms, leg blockages and the like well known in the art.

Another optional component that may be included in the absorbent article of the present invention is odor control means. That is, any suitable odor control means can be incorporated into the product of the present invention in any desired form such as granular, capsule / microcapsules, powder or impregnation according to techniques well known in the art.

Absorbent articles of the present invention are typically manufactured and packaged as essentially flat products, and are therefore easier to manufacture and package than conventional elasticized or preformed products. Since the three-dimensional structure is formed only during use, the product of the present invention is also easier and more comfortable to wear.

Claims (10)

An absorbent article comprising a top sheet, a back sheet and an essentially planar absorbent core disposed between the top sheet and the back sheet, the absorbent article comprising: The absorbent core comprises an absorbent expandable material and has a central region and a peripheral region in its plane, Wherein the absorbent expandable material is used to concentrate the absorbed liquid into the central region of the absorbent core, Use of an absorbent expandable material to absorb liquid into the absorbent article. The method of claim 1, Absorbent expandable material upon initial absorption of the liquid expands by a volume greater than the volume of the absorbed liquid, thereby creating an additional void volume. The method according to claim 1 or 2, Use by which an absorbent expandable material extends through the central region of the absorbent core. The method according to any one of claims 1 to 3, Use of the absorbent expandable material not stretching into the surrounding area of the absorbent core. The method according to any one of claims 1 to 4, And wherein the absorbent expandable material primarily expands upon absorption of the liquid in a direction perpendicular to the essentially planar absorbent material. The method of claim 5, And wherein the absorbent expandable material expands in a direction from the absorbent core toward the top sheet. The method according to any one of claims 1 to 6, The absorbent expandable material comprises a regenerated cellulose sponge material, preferably consisting of a regenerated cellulose sponge material. The method of claim 7, wherein And wherein the cellulose sponge material has an incision in a direction perpendicular to the essentially planar absorbent core and preferably comprises a perforation in the cellulose sponge material on the surface of the cellulose sponge material closest to the top sheet. The method according to any one of claims 1 to 8, Each material contained in the absorbent core has a maximum planar liquid transport capacity inwardly in the planar absorbent core, and each material in the absorbent core has a maximum vertical liquid transport capacity in a direction perpendicular to the essentially planar absorbent core. And wherein the value of the maximum planar liquid transport capacity is less than the value of the maximum vertical liquid transport capacity for at least 50%, preferably at least 95%, of the volume of the material. The method according to any one of claims 1 to 9, The absorbent product is a sanitary napkin.