MXPA97000327A - Absorbent with section measure of gelificac material - Google Patents

Abstract

The present invention relates to an absorbent structure (1), especially adapted for use by users in a predominantly lying position, a relatively high weight of gelling absorbent material in the rear middle section (3) of the absorbent structure (1). Preferably between 55% and 100% of the total weight of the gelling absorbent material, most preferably between 60% and 90%, is located in the rear middle section (3). In one embodiment of the absorbent structure (1), the average base capacity in the posterior middle section (3) of the core is between 1.1 times to 3 times the average base capacity in the middle section front

Description

ABSORBENT WITH AVERAGE SECTION OF MATERIAL GELIFICATION FIELD OF THE INVENTION Absorbent structure comprising: at least one layer of fibrous or foamed absorbent material, - a perimeter comprising a front transverse edge, a rear transverse edge and two longitudinal sides, - a transverse center line located midway between the front transverse edge and the rear transverse edge, - a front midsection located between the transverse center line and the front transverse edge, and - a rear middle section located between the transverse center line and the rear transverse edge, and - gelling absorbent material. The invention also relates to an absorbent article comprising said structure.

BACKGROUND OF THE INVENTION In the field of absorbent product technology, many attempts have been made to improve the absorbent capacity and the efficiency of absorbent cores, providing regions of base weight and increased or decreased density, in such cores. In U.S. Patent No. 4,935,022 (Lash) an absorbent structure is described, which has a lower storage layer and an upper acquisition / distribution layer, comprising chemically hardened cellulose fibers and gelling absorbent material. The upper acquisition / distribution layer has a larger surface area than the underlying storage layer. The lower storage layer is formed of an insert, which is placed in relation to the upper acquisition / distribution layer, so that approximately 75% of the gelling absorbent material in the lower layer, is in the front section of two. thirds of the absorbent structure, and at least 55% of the total amount of the gelling absorbent material is in the mid-front section. In U.S. Patent No. 4,685,915, (Hasse) an absorbent product having a core comprising hydrophilic fibers and gelling absorbent material is described, the core having an area with an average density and a basis weight greater than the end portions of the core. The area of average density and larger basis weight is located near the center or in the front of the absorbent product. In United States Patent No. 4,834,735 (Alemany) describes an absorbent core having a storage zone and a acquisition region of average density and basis weight less than the storage area. The core comprises a mixture of hydrophilic fibers and absorbent gelling particles. The acquisition region is located towards the front of the absorbent core. < * - European Patent No. EP-B-0 330 675 describes the introduction of the gelling absorbent material to specific locations of a horizontal plane or x-y of an absorbent core using pulsed powder spray guns. In the international patent applications Nos.

W091 / 11163 and W091 / 11165, there is disclosed a dual layer core comprising a lower storage layer and an upper fluid acquisition / distribution layer, comprising chemically hardened cellulose fibers, the upper layer being substantially free of absorbent material of gelation. The area of the acquisition / distribution layer is between 25% and 100% of the area of the lower storage layer, and preferably has an elongated shape. For adult incontinence products, the acquisition / distribution layer is generally located in the front two-thirds of the absorbent article, relative to the backing sheet. In U.S. Patent No. 4,411,660 (Dawn), an absorbent article is described wherein a layer consisting of gelling absorbent material is on a fibrous layer. The layer of gelling absorbent material may be in the form of particles, fibers or a film. In the international patent application O91 / 04724, a diaper core is described, which linearly tapers from a relatively narrow leg section towards a relatively wide back section. The applicant has observed that especially the category of adults suffering from incontinence, there is an increased tendency of the spill of the absorbent products, when the user is lying down. Most adults who suffer from severe incontinence are older women, where the spill in these positions is relatively frequent compared to other users. It is an object of the present invention to provide an absorbent product, which provides a small spill when lying down. It is another object of the invention to provide an absorbent article that is especially adapted for users ranging from babies starting to walk to adults, when confined to a predominantly lying position.

It is also another object of the invention to provide an absorbent article that is especially reduces spillage among female users, when confined to a predominantly lying position. An absorbent structure according to the invention is characterized in that the weight of the gelling absorbent material located in the rear middle section of the structure is greater than the weight of the gelling absorbent material located in the front middle section of the structure. With "back middle section" of the absorbent structure is meant that the part of the absorbent structure that is in use is intended to make contact with the user's genitals and buttocks and extends generally towards the user's back. Preferably, between 55% and 100% by weight of the gelling absorbent material is located in the middle rear section. More preferably between 60% and 90%, and most preferably between 65% and 80% of the gelling absorbent material is in the middle rear section. By concentrating the absorbent material in the posterior middle section of the absorbent article, urine is prevented from spilling from the product when it is used when lying down. Hence, the absorbent structures according to the invention are specially adapted to the specific needs of bedridden people.

In one embodiment of an absorbent article, according to the present invention, the absorbent material may comprise, in addition to the absorbent gelling material, hydrophilic fibers such as lint pulp, rayon fibers or modified cellulose fibers, or may comprise an absorbent material in foam as described in U.S. Patent No. 5,268,224 (Desmarais). The application of more absorbent material of this type in the rear middle section of the absorbent structure can result in the so-called profiled core, which is of a larger caliber in the posterior middle section than in the front mid section. Alternatively, the absorbent structure is compressed to a uniform gauge, so that the density of the structure is higher in the posterior middle section. In an alternate embodiment of the absorbent structure according to the invention, the total weight of the • - absorbent material in the rear middle section against the total weight of the absorbent material in the front middle section. For example, the surface area of the absorbent material layer in the middle back section may be larger than the surface area of the absorbent material in the front mid section at equal base weights of absorbent material in the middle rear and middle half sections. For example, the distance between a longitudinal side of the absorbent structure and the longitudinal center line can increase substantially monotonically when going from the transverse center line to the rear transverse side. In this way, a greater surface area of absorbent material is provided in the rear middle section, "which not only provides increased absorbent capacity but also provides improved softness and cushioning to the user. In a further embodiment of an absorbent structure according to the invention, the amount of gelling absorbent material per unit area, or average basis weight, is greater in the rear middle section than in the mid front section. The average basis weight of the gelling absorbent material in the front middle section and in the rear middle section is determined by measuring the total weight of the gelling absorbent material present in any section and dividing this weight by the total area, in which the absorbent material of gelation. The weight of the gelling absorbent material is determined by separating the gelling absorbent material from the other absorbent material in any section. The area, where the gelling absorbent material is placed, is measured by applying a coloring agent to the absorbent core, such as bromocresol. The color areas are detected by visual inspection. Alternatively, the absorbent core can be exposed to X-rays to detect the amount and location of the material . f absorbent of gelation. In another embodiment of an absorbent structure according to the invention, the average base capacity in the posterior middle section is greater than the average base capacity in the mid-front section. The average base capacity is a measurement for the amount of liquid that can be retained per gram of the absorbent material. The average base capacity will depend on the amount and type of absorbent material in the middle front section and the middle section later. The absorbent material in any section may comprise, for example, gelling absorbent material, fibers, foam, interpartically intertwined aggregates or any combination thereof. The average base capacity is measured according to a test method, which is based on the official method established by Germany "Medizinischer Dienst der , Spitzenverbánde der Krankenkassen eV ", for the reintegration of absorbent products for incontinence The test method" Prüfmethode Nr. 1/93 MDS-HI Teil 1, Bestimmung der Flüssigkeitsaufnahme "is found in the detailed description of the invention, which In a further embodiment of an absorbent structure according to the invention, an acquisition / distribution layer lies on a lower layer of absorbent material, such that the acquisition / distribution layer is for a greater part located in the upper layer of the posterior middle section of the lower layer When the acquisition / distribution layer is generally elongated, a greater length of this layer extends through the posterior middle section of the underlying layer of the absorbent material. of acquisition / distribution is generally circular in shape, or is relatively irregularly formed, a larger surface area of the acquisition / distribution layer extends through the posterior middle section of the underlying layer through the mid-front section. The acquisition / distribution layer comprises fibers that maintain their elasticity even when wet, such that the absorbent capacity of the acquisition / distribution layer does not decrease when capturing consecutive jets of liquid. This property is expressed by the wet compression capacity of the acquisition / distribution layer of at least 5 cm3 / g and a drip capacity of at least 10 g / g. Hydrophilic fibers having this property are among the chemically hardened cellulosic fibers as described in U.S. Patent Nos. 4,898,642 (Moore), 4,889,597 (Bourbon), 4,889,596 (Schoggen), 5,160,789 (Barcus), 5,049,235 (Barcus. ) and 4,822,453 (Dean), or by hydrophilic synthetic fibers, such as polyester fibers.

The acquisition / distribution layer can alternatively and additionally comprise several types of two-component fibers that are thermally bonded to form an open structure. Such fibers are described in EP-A-0513148 and U.S. Patent Application No. 08 / 141,156. The acquisition / distribution layer serves to quickly collect large jets of liquids and to rapidly direct these away from the user's body. The "acquisition / distribution" layer has a relatively low density, for example, between 0.03 and 0.13 g / cm 3. The liquids are only temporarily stored in the acquisition / distribution layer, the acquisition / distribution layer is drained. through the underlying storage layer, such that it is quickly emptied and ready for the capture of additional liquid jets By draining the acquisition / distribution layer, a layer of gelling absorbent particles can be located directly below the layer acquisition / distribution Preferably, this gelling absorbent material is of high gel-resistance, such that the particles of the gelling absorbent material do not deform to an extent while forming a gelled mass that is relatively impervious to liquid. Preferably the gelling absorbent material used directly below the acquisition layer n / distribution has a Gel Layer Permeability (PCG) value greater than 4 x 10-7 cm3 / s / g. The gelling absorbent materials of these PCG values, maintain a relatively open structure when wet and maintain good liquid transport properties in the vertical direction (Z direction) and horizontal direction (x-y), even when wet.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in detail with reference to the accompanying drawings. Figure 1 shows a front elevation view of an absorbent article comprising an absorbent structure according to the invention. Figures 2 to 5 show cross-sectional views of the absorbent structure of Figure 1, as - > length of the longitudinal centerline. Figure 6 shows a front elevation view of an absorbent structure comprising an acquisition / distribution layer. Figure 7 shows a cross-sectional view of the structure of Figure 6 along the longitudinal center line. Figure 8 shows a front elevation view of an absorbent structure having an acquisition / distribution layer. Figure 9 shows a cross-sectional view of an absorbent structure having a layer of gelling absorbent material located directly below the acquisition / distribution layer. Figure 10 shows a front elevational view of the absorbent structure having a relatively large posterior surface area section. Figure 11 shows schematically the region for measuring the average base capacity of an absorbent structure. Figure 12 shows schematically the test equipment for measuring the average base capacity of an absorbent structure.

DETAILED DESCRIPTION OF THE INVENTION ** As used herein, the term "absorbent article" refers to devices, which absorb and contain body exudates, and, more specifically, refer to devices, which are placed against or close to the body of the user to absorb. and containing the various exudates discarded from the body. The term "disposable" is used herein to describe absorbent articles, which are not intended to be washed or otherwise remanufactured or reused as an absorbent article (ie, intended to be discarded after only one use and, preferably, be recirculated, mixed or otherwise arranged in an environmentally compatible manner). A "unitary" absorbent article refers to absorbent articles, which are formed of separate parts joined together to form a coordinated entity, so that they do not require separate handling parts, such as a separate support and liner. . A preferred embodiment of an absorbent article of the present invention is a disposable, unitary absorbent article, or diaper, as shown in Figure 1. As used herein, the term "diaper" refers to an absorbent article generally used by babies who start walking and incontinent people, which is used around the user's lower torso. It should be understood, however, that the present invention is also applicable to other absorbent articles such as incontinence briefs, incontinent underwear, diaper liners and the like. Figure 1 shows an absorbent article 1, comprising a structure or an absorbent core 3. The absorbent core 3 comprises a perimeter 5 having a front transverse edge 7, a rear transverse edge 9, and two longitudinal sides 13, 13 '. An imaginary transverse centerline 15 is located in the middle part, between the front transverse edge 7 and the rear transverse edge 9, and divides the core 3 into a front midsection 17 and a rear midsection 19. In the absorbent core, of according to the invention, the amount of gelling absorbent material in the rear middle section 19 is greater than the amount of gelling absorbent material in the front midsection 17. Preferably, the average amount of the gelling absorbent material per unit area, or average basis weight, in the rear middle section 19 is greater than in the front midsection 17, at least in the middle section 6a- 6f as indicated in Figure 11. In Figure 1, the absorbent article, or diaper 1 , shown in its non-contracted, flat state (ie, with elastic induced contraction pulled), with portions of the article cut to show more clearly the construction the diaper 1, and with the portion of the diaper 1, which looks or is ^ in contact with the user, the internal surface, facing the viewer. As shown in Figure 1, the diaper and preferably comprises a topsheet 24 permeable to liquid; a backing sheet 26 impervious to liquid, attached to the topsheet 24; the absorbent structure or core 3, being positioned between the topsheet 24 and the backsheet 26; folds with elastic 32, 32 'for the legs; an elastic 34 accessory for the waist; and a generally multiplied fastening system, designated 36, and located in the back waist region 58 of the diaper. Figure 1 shows a preferred embodiment of the diaper 1, in which the topsheet 24 and the backsheet 26 have length and width dimensions generally greater than those of the absorbent core 3. The topsheet 24 and the backsheet 26 are extend beyond the perimeter 5 of the absorbent core 3. Since the topsheet 24, the backsheet 26, and the absorbent core 3 can be assembled in a variety of well-known configurations,. Preferred diaper configurations are generally described in U.S. Patent No. 3,860,003, entitled "Contractable Side Portions for Disposable Diaper".

("Contractible Side Portions for Disposable Diapers"), which is issued to Kenneth B. Buell, on January 14, 75; and the United States patent application series No. 07 / 715,152, granted, "Absorbent Article With Dynamic Elastic Waist Feature Having a Predisposed Resilient Flexural Hinge ", / _- ("Absorbent Article with a Elastic Accessory, Dynamic for the Waist, that Has a Hinge of Elastic Flex, Predisposed"), Kenneth B. Buell and others, presented on June 13, 1991; each of which is incorporated herein by reference. The absorbent core 3 may be any absorbent means, which are generally compressible, comfortable, non-irritating to the wearer's skin, and capable of absorbing and retaining liquids such as urine and other exudates from the body.

The absorbent core 3 can be manufactured in a wide variety of sizes and shapes (e.g., rectangular, hourglass, T-shaped, asymmetric, etc.) and from a wide variety of absorbent materials. liquid commonly used in disposable diapers and other absorbent articles such as crushed wood pulp, which is generally referred to as air felt. Examples of other suitable absorbent materials include creped cellulose wadding; blown polymers under fusion including coform; chemically hardened, modified or interlaced cellulosic fibers; gauze including gauze wraps and gauze sheets; absorbent foams; absorbent sponges; superabsorbent polymers; gelling absorbent materials; or any equivalent material or combinations of materials. The configuration and construction of the absorbent core can also be varied (e.g., the absorbent core can have zones of varying gauge, a hydrophilic gradient, a superabsorbent gradient, or acquisition zones of lower average density and lower average basis weight; or may comprise one or more layers or structures). However, the total absorbent capacity of the absorbent core 3 must be compatible with the design load and intended use of the diaper 1. In a preferred embodiment, according to the invention, the absorbent core is intended to be used by adults or youth and is able to absorb between 100 and 1000 ml of body fluids. In addition, the size and absorbent capacity of the absorbent core 3 can be varied to suit users, ranging from babies to adults. Exemplary absorbent structures, for use as the absorbent core 3, are described in U.S. Patent 4,610,678, entitled "High-Density Absorbent Structures", issued to Weisman et al. September 1986; U.S. Patent 4,673,402, entitled "Absorbent Articles With Dual-Layered, Cores" ("Absorbent Articles with Double Layer Cores"), issued to Weisman et al., June 16, 1987; U.S. Patent 4,888,231, entitled "Absorbent Core Having a Dusting Layer" ("Absorbent Core Having a Powder Coating"), issued to Angstadt, on December 19, 1989; and U.S. Patent 4,834,735, entitled "High Density Absorbent Members Having Lower Density and Lower Basis Weight Acquisition Zones "(" Absorbent Members of Alta _: __ Density of Lower Density and Lower Base Weight Acquisition Zones "), issued to Alemany et al. On May 30, 1989. Each of these patents is incorporated herein by reference.A preferred embodiment of the absorbent core 3 is having a longitudinal dimension, L, of approximately 60 cm, a rear transverse edge 9 of approximately 30 cm, a front transverse edge 7 of 30 cm and a width, along the transverse center line 15, of approximately 20 cm. The backsheet 26 is positioned adjacent the garment surface of the absorbent core 3, and is: preferably attached thereto by attachment means (not shown), such as those well known in the art. backing 26 can be secured to the absorbent core 3 by means of a continuous, uniform layer of adhesive, a molded layer of adhesive, or a separate line, spiral or dot arrangement of adhesive. The adhesives that have been found satisfactory are manufactured by H.B. Fuller Company of St. Paul, Minnesota, and sold as "" HL-1258. The attachment means will preferably comprise an open pattern, adhesive filament network, as described in U.S. Patent No. 4,573,986, entitled "Disposable Waste-Containely Garment" ("Waste Disposable Garment"), issued to Minetola et al. on March 4, 1986, most preferably several filament filament lines wound in a spiral pattern, as illustrated by the apparatus and methods shown in United States Patent No. 3,911,173, Issued to Sprague, Jr., on October 7, 1975; U.S. Patent No. 4,785,996, issued to Ziecker et al., November 22, 1978; and U.S. Patent No. 4,842,666, issued to Werenicz, June 27, 1989. Each of these patents is incorporated herein by reference. Alternatively, the joining means may comprise heat bonds, pressure joints, ultrasonic bonds, dynamic mechanical joints, or any other means of joining or combinations of these joining means, as are well known in the art. The backsheet 26 is impervious to liquids (eg, urine), and preferably is made from a thin plastic film, although other, flexible, liquid impervious materials can also be used. As used herein, the term "flexible" refers to materials, which are condescending and will readily conform to the general shape and contours of the human body. The backsheet 26 prevents the exudates absorbed and contained in the absorbent core 3, from wetting the articles that are in contact with the diaper 1, such as sheets and underwear. The backsheet 26, thus, may comprise a woven or non-woven material, polymeric films, such as polyethylene or polypropylene thermoplastic films, or mixed materials, such as non-woven material. / _ woven, coated with film. Preferably, the backsheet is a thermoplastic film having a thickness of about 0.012 mm to about 0.051 mm. Particularly preferred materials for the backsheet include meltblown films, RR821, and cast films, RR5475, such as those manufactured by Tredegar Industries, Inc. of Terre Haute, IN. The backsheet 26 is preferably stamped and / or finished to matte, to provide an appearance of more than the type of clothing. In addition, the backsheet 26 can allow the vapors to escape from the absorbent core 3 (ie, breathable), while preventing exudates from passing through the backsheet 26. The topsheet 24 is positioned adjacent to the surface of the absorbent core body 3, and is preferably attached thereto and backing sheet 26, by attachment means (not shown), such as those well known in the art. Suitable attachment means are described with respect to the attachment of the backsheet 26 and the absorbent core 3. As used herein, the term "attached" encompasses configurations, by which one element is directly secured to the other element. , fixing the element directly to the other element, and configurations, by means of which the element is indirectly joined to the other element, fixing the element to the intermediate member (s), which, in turn, are fixed to the other element. In a preferred embodiment of the present invention, the topsheet 24 and the backsheet 26 are bonded directly to each other, on the periphery of the diaper and are indirectly attached, as a whole, by attaching them directly to the absorbent core 3 by the attachment means ( not shown). The topsheet 24 is condescending, gentle in feel, and non-irritating to the wearer's skin. In addition, the topsheet 24 is permeable to liquid, allowing liquids (e.g., urine) to easily penetrate through its thickness. A suitable top sheet can be manufactured from a wide variety of materials, such as porous foams; cross-linked foams; plastic films with openings; or woven or nonwoven webs of natural fibers (e.g., wood or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers), or a combination of natural or synthetic fibers. Preferably, the topsheet 24 is made of a hydrophobic material to isolate the wearer's skin from the liquids contained in the absorbent core 3. The hydrophobic material may have a hydrophilic coating. There are a number of fabrication techniques, which can be used to manufacture the topsheet 24. For example, the topsheet 24 can be a non-woven web of spunbonded, carded, wetlaminated, meltblown, hydroentangled fibers. , combinations of the above, or similar. A preferred topsheet is carded and thermally bonded by means well known to those skilled in the art of fabrics. A preferred topsheet comprises a band of short fibers of polypropylene, such as manufactured by Veratec, Ine, a division of the Division of International Paper Company, of Walpole, Massachusetts under the designation P-8. The diaper 1 may also comprise elastic folds 32, 32 ', for the legs, to provide improved containment of liquids and other body exudates. Each elastic fold 32, for the legs, can comprise several different modalities to reduce the spillage of exudates from the body in the leg regions. (The fold of the leg can be, and is sometimes referred to as leg bands, side flaps, barrier folds, or elastic folds). U.S. Patent No. 3,860,003 discloses a disposable diaper, which provides a collapsible leg opening, having a side flap and one or more elastic members to provide an elastic fold for the legs (tie fold). U.S. Patent No. 4,909,803, entitled "Disposable Absorbent Article Having Elasticized Flaps" ("Disposable Absorbent Article Having Elastic Fins") issued to Aziz et al., Lo. March 1990, describes a disposable diaper having elastic flaps "straight", (barrier folds), to improve the containment of the leg regions. The United States patent No. 4,695,278 entitled "Absorbent Article Having Dual Cuffs" ("Absorbing article having dual folds"), issued to Lawson, on September 22, 1987, describes a disposable diaper having dual folds that include a tie fold and a barrier fold. The diaper l preferably further comprises a waist elastic attachment 34, which provides improved fit and containment. The waist elastic attachment 34 is that portion or area of the diaper, which is intended to be elastically expanded and contracted to be dynamically attached "to the wearer's waist.The waist elastic attachment 34 at least extends longitudinally outwardly from above. at least one of the waist edges of the absorbent core 3, and generally forms at least a portion of one of the waist regions 56 or 58 of the diaper 1. The disposable diapers are generally constructed in order to have two elastic accessories of waist, one placed in the first waist region, and one placed in the second waist region, although diapers can be constructed with a single waist attachment.Also, since the waist elastic attachment or any of its constituent elements may comprise a separate element fixed to the diaper 1, the elastic waist accessory 34 is preferably constructed as an extension of other diaper elements, such as the backsheet 26 or the topsheet 24, preferably both the backsheet 26 and the top sheet 34. The waist elastic band 34 can be constructed in a number of different configurations, including those described in U.S. Patent No. 4,515,595, issued to Kievit et al., May 7, 1985, and U.S. Patent Series No. 07 / 715,152, cited above; each of these descriptions is incorporated herein by reference. The diaper 1 also comprises a fastening system 36, which forms a lateral closure, which maintains the first waist region 56 and the second waist region 58 in an overlapping configuration, so that lateral stresses are maintained around the circumference of the diaper to maintain the diaper on the wearer. Illustrative fastening systems are described in U.S. Patent No. 4,846,815, entitled "Disposable Diaper Having An Improved Fastening Device", issued to Scrips, on July 11, - '- 1989; U.S. Patent No. 4,894,060, entitled "Disposable Diaper With Improved Hook Fastener Portion" ("Disposable diaper with improved portion of hook fastening"), issued to Nestegard, January 16, 1990; U.S. Patent No. 4,946,527, entitled "Pressure-Sensitive Adhesive Fastener and Method of Making Same" ("Pressure sensitive adhesive fastener and method for making the same"), issued to Battrell on August 7, 1990; U.S. Patent No. 3,848,594, entitled "Tape Fastening System for Disposable Diaper", issued to Buell, November 19, 1974; U.S. Patent No. 4,662,875, entitled "Absorbent Article" ("Absorbing Article"), issued to Hirotsu et al., May 5, 1987; and U.S. Patent Application No. 07 / 715,152, cited above; each of which is incorporated herein by reference.

Figure 2 shows a cross-sectional view of the core 3 along the longitudinal center line 16. Within the core 3, four sections, 13a, 13b, 13c and 13d, of equal length, L / 4, can be considered. core size being different in each section. In the embodiment of Figure 2, the core 3 comprises lint pulp of uniform density. The caliber of section 13a is approximately 7 mm. The caliber in section 13b is approximately 10 mm, the gauge of the section 13c is approximately 8 mm, and the '' gauge in the section I3d is approximately 5 mm. Therefore, the ratio of the base weights of the fibers of the combined sections 13a and 13b, which form the rear middle section of the core 3, and the combined sections 13c and 13d, which form the front middle section, is approximately 1.3. The core 3 may comprise cellulosic fibers, synthetic fibers such as crimped polyester fibers, blends of synthetic fibers and cellulosics of foam absorbent material, as described in U.S. Patent No. 5,268,224 (Desmarais). The core 3 caliber, as shown in Figure 2, can be made uniform by calendering. This is illustrated in Figure 3. The core 3 of Figure 3 comprises areas of relatively high density in the rear middle section 13a, 13b, and a relatively low density in the front midsection 13c, 13d. The density of the fibrous or foamy absorbent material, in the J front and rear middle sections can vary from 0.1 to 1 g / cm3. The density in each section is proportional to the caliber before calendering to a uniform caliber. The increased density of the fibers, in the posterior middle section, improves the retention of liquids, since the section with smaller capillaries between fibers, will exert a superior suction of liquids in the posterior middle section. The core 3, in Figures 2, 3 and 4, comprises a water-insoluble gelling absorbent material, which swells upon contact with liquids to form a hydrogel. Such materials are described, in detail, in U.S. Patent No. Re. 32,649 (Brandt), and can absorb at least 20 times their own weight, of liquid. The hydrogel material can be in a particulate form, the particle sizes varying from 10 micrometers to 2000 micrometers, or they can be in the form of flakes, fibers or • / sheets. The hydrogel material may also be composed of an interparticularly interlaced aggregate, as described in U.S. Patent No. 5,102,597 (Roe). The core 3, in Figure 4, comprises a lower layer 63, which is substantially free of gelling absorbent material, or which contains particles of gelling absorbent material, of small size, or fine particles of gelling absorbent material, as described in EP-A-0 567 738 (Plishke). The lower layer 63 serves to contain the gelling absorbent material in the upper layer 64 and to prevent the particles of the gelling absorbent material from coming into contact with the backing sheet and thereby causing irregularities in the surface on the sheet of metal. backing (the so-called "smallpox mark), and to prevent the gelling absorbent material from piercing the backsheet In the absorbent core of Figure 4, the gelling absorbent material is uniformly dispersed throughout the thickness, W, of each region 13a-13d of layer 64. However, the gelling absorbent material may be present in different concentrations through the thickness of layer 64 of core 3, and may be higher in those parts of the core that are more away from the user (those parts of layer 64 that are located very close to layer 63) said nuclei with a so-called "gradient" of absorbing material gelling agent, are described in detail in EP-A-0 198 683 (Duenk) In the embodiment of Figure 4, the basis weight of the gelling absorbent material, in section 13a, is about 0.012 g / cm2, the basis weight in section 13b being about 0.016 g / cm2, the basis weight in the section 13c being approximately 0.012 g / cm2, and the basis weight in section 13d being approximately 0.008 g / cm2. In a preferred embodiment, the section 13a contains approximately r * 25%, and the section 13b contains approximately 35% by weight of the total amount of the gelling absorbent material present in the layer 64. The section 13c can contain approximately 25% and the section 13d approximately 5% of the total weight of the gelling absorbent material in the layer 64. Preferably, the gelling absorbent materials are "high formative resistance" materials ___ gel. "The gel-absorbing material particles, which are highly resistant to gel formation, will suffer a relatively small deformation when wetted, so that the gelling material does not flow into the capillary hollow space of the fibrous material, and causes an unwanted gel blockage, suitable gelling absorbent materials have higher Gel Layer Permeability (PCG) values «That 4 x 10-7 cm3 / s / g. The value of PCG can be measured by means of. the method described in European application No. 93309614.1. In the embodiment of Figure 4, the basis weight of the fibrous or foamed absorbent material is the same for sections 13a-13d in layer 64. The basis weight of the fibrous or foamed absorbent material typically may be about 0.05 g / m2. Nevertheless, in addition to a variable basis weight of the gelling absorbent material for each section 13a-13d, the basis weight of the fibrous or foamable absorbent material may also vary in each section 13a-13d, as shown in Figure 5. Again, the Core 3, as shown in Figure 5, can be calendered to a uniform gauge. In Figure 6 there is shown a top plan view of an embodiment of an absorbent core 3 comprising an acquisition / distribution layer 69, located in the upper part of the layer 64 of the core 3. The adsorption / distribution layer it serves to quickly collect large jets of liquids and to isolate these from the user's body until these liquids have been absorbed in the underlying layer 64. The density of the acquisition / distribution layer is preferably between 0.03 and 0.13 g / cm3, the base weight being between 100 and 500 g / m2, depending on the volume of the jet to be collected. A preferred material for the acquisition / distribution layer 69 is a chemically hardened cellulose material, as described in EP-A-0 429 112 (Herron), U.S. Patent No. 4,898,642 (moore) and 4,889,597 (Bourbon) . Other acquisition / distribution layers may comprise open networks of thermally bonded synthetic fibers, as described in U.S. Application No. 08 / 141,156 and EP-A-513 148. An Important Property of the Acquisition / Distribution Layer 69 is its ability to maintain a sufficient volume of space for liquid consumption, even when it is wet. The fibers in layer 69 must be sufficiently elastic so as not to crush in their wet state under compression. It has been found that layers having a wet compression capacity of at least 5 cm3g "1 and a drip capacity of at least 10 gg" 1, can be successfully used in the acquisition / distribution layer 69. The capacity Wet compression and drip capacity can be measured by the test described below. All tests are carried out at approximately 23 + 2_C and at a relative humidity of 50 ± 10%. The specific synthetic urine used in the test methods is commonly known as Jayco SynUrine and is available from Jayco Pharmaceuticals Company of Camp Hill, Pennsylvania. The formula of synthetic urine is: 2.0 g /: KCl; 2.0 g / 1 Na2S04; 0.85 g / 1 of (NH4) H2P04; 0.15 g / 1 of (NH4) H2P04; 0.19 g / 1 CaCl2; and 0.23 g / 1 MgCl2. All chemical products are reactive grade. The pH of synthetic urine is in the range of 6.0 to 6.4.

Preparation of a Sample Pad for the Tests of Compression Capacity in Humid and of Drip Capacity.

The sample pads were prepared using a pad-forming machine of the type described below or an equivalent machine, which provides a consistent and homogeneous lint template. 30 g of dry lint portions (or equivalent material, eg, chemically interlaced cellulose) were weighed. A layer of gauze, sufficiently porous for air to pass through it, while retaining the lint therein, is cut to 36.8 cm x 36.8 cm, and is uniformly placed on a screen forming a paver forming machine. air felt or laying. The gauze completely covers the forming screen and is made to curl at its sides to prevent the lint from escaping. The gauze forms the bottom of the pad. The vacuum chamber motor and the supply of compressed air are turned on the pad-making machine. A portion of 30 g of lint is added to the sample chamber in the pad-forming machine, in small quantities, via a sample feed and without obstructing the blades of the sample. - * 'machine. Compressed air is circulated vigorously in the chamber to facilitate the separation and passage of the fibers through the plexiglass cylinder and the prismoid column towards the forming screen. The vacuum is deactivated and the forming screen is pulled out of the pad-forming machine and rotated a quarter turn in a clockwise direction. The screen is returned to the pad-making machine. Another 30 g portion of lint is added to the chamber in the machine, and the above procedure is repeated. The lint is added in the same manner, until four portions have been transferred to the forming screen. The forming screen, and the pad formed therein, are removed after the pad-forming machine, and the pad is carefully transferred from the screen to a piece of cardboard, or similar, flat, smooth surface. A second layer of gauze is added to the top of the pad, and a second piece of cardboard and -, - is placed on top. A load of steel, with dimensions around . 6 cm x 35.6 cm x 2.5 cm, weighing approximately 16.3 kg, is placed on top of the pad for approximately 120 seconds, or longer, until the pad is needed. Then, the load is removed and the pad is compressed by applying a force of about 4,500 kg on a Carver press to improve the integrity of the pad. The pad is removed from the press and cut on a paper cutter so that it has dimensions around 30.5 cm x 30.5 cm, and then it is cut again more, according to the size required by the particular test, in which it will be used. The use of the pad-forming machine for making sample pads is not intended to be limiting. Any suitable method can be used, provided that it obtains a consistent and homogeneous lint template, which is "" "" compressed then under the above conditions to give a pad having substantially the same density and basis weight, as achieved previously.

Wet Compression Capacity Test This test is designed to measure the volume of a pad of fibrous material under varying load conditions, when wet. The objective is to measure the resistance of the fibrous material to a load, measuring the volume maintained under that load. A test pad of lint is prepared as described above. Any gauze present on the pad surfaces was removed. Afterwards, the pad was densified under a load of 3.6 kg / cm "2, for reasons of pad integrity, using a press ^ Carver's laboratory. The thickness of the pad was measured and its fiber density was calculated by the weight of the pad - (pad thickness x pad area). The dry weight of the pad is multiplied by 10, and this represents the wet target weight on the load. The dry pad is transferred on a top loading equilibrium having a sensitivity of 0.01 g. Synthetic urine is slowly dispensed onto the pad until the target wet weight is obtained, as measured by the balance. The wet pad is carefully transferred onto the surface of a compression capacity tester of the Buckeye design, and a weight that has substantially the same area as the pad (approximately 10.2cm x 10.2cm) and corresponding to a pressure of 77 g. / cm "2, is lowered slowly on the pad, the pad is left 60 seconds, to allow it to equilibrate under the load, and then the thickness of the compressed pad, is recorded using gauges. is the hollow volume per gram of dry lint and is calculated as follows: Hollow volume (cm3) = total volume - fiber volume = (thickness of pad under load (cm) x area of the pad (cm2)) - (dry weight) of the pad (g) / fiber density (g / cm3)) Wet compression capacity = hollow volume per gram = [(thickness of pad under load (cm) x area of the; J "pad (cm2)) - (pad dry weight (g) / fiber density (g / cm" 3)] - pad dry weight (g), where the fiber density is calculated at Starting from the initial weight of the pad and the thickness measurements (ie, under no load condition).

Drip Capacity Test A sample pad, prepared as described above, was cut on a paper cutter to dimensions of 7.5 cm x 7.5 cm. The pad was weighed and placed on a large mesh wire screen, which in turn was placed on a drip tray. Then, the entire apparatus was mounted on a top loading scale. Synthetic urine was introduced by means of a pump (model 7520-00, as supplied by Cole-Parmer Instruments Company, Chicago, United States), towards the center of the sample pad at a speed of 5 + 0.25 ml / s "1. Time was recorded for the pad to release the first drop of synthetic urine through the bottom of the pad and into the drip tray.The pump is immediately stopped after this occurs.The time recorded and the speed of pumping they are then used to calculate the volume (mi) of synthetic urine absorbed by the sample upon reaching saturation, ie when the sample begins to drip.The equilibrium can be used to verify this periodically, thus minimizing any variation in the pump It supplies the synthetic urine, this is known as the drip capacity, and is given as the ratio of: . { Urine retained by the sample pad at saturation (ml)} /. { Dry weight of the sample (g)} Figure 7 shows a cross-sectional view of the core 3 of Figure 6. In the embodiment of Figures 6 and 7, the acquisition / distribution layer 69 has a generally rectangular shape and comprises a trailing edge 73 and a leading edge 75 The distance between the trailing edge 73 of the acquisition / distribution layer 69 and the transverse centerline 61 is greater than the distance between the leading edge 75 and the transverse center line. For acquisition / distribution layers 69, irregularly configured, the surface area of the acquisition / distribution layer portion 69, located between the transverse center line 15 and the trailing edge 9 of the core 3, is greater than the surface area of the acquisition / distribution layer 69, located between the transverse center line 15 and the leading edge 7 of the core 3. Preferably, the ratio of the total weight of the absorbent material in the acquisition / distribution layer, located in the posterior middle section of the absorbent core 3 and located in the anterior middle section of the acquisition / distribution layer, is between 1.1 to 3. In the embodiment of Figure 9, an extra layer 71 of gelling absorbent material is located below the layer of absorbent material. acquisition / distribution 69. This layer of gelling absorbent material serves to rapidly drain layer 69, so that it is ready for subsequent liquid jets, and It has a dry pH regulator adjacent to the user's skin. The high gel-resistance gelling absorbent materials, as mentioned above, are suitable for use in layer 71, since they maintain a relatively open structure, through which liquids can pass into the underlying layer 64, without presenting Adverse effects of gel block. The gelling absorbent material, in the layer 71, can be mixed with the fibers in the upper part of the layer 64, and can be introduced in this layer during the air laying of the fibers of the layer 64, using a nozzle of powder coating, as described in EP-B-0 330 675. Alternatively, layer 71 contains a layer of gelling absorbent material, which does not substantially mix with the fibrous or foamed absorbent material of layer 64. Such layer of gelling absorbent material can be attached to a gauze by means of adhesive or frictional forces, as described in U.S. Patent No. 4,600,458 (Kramer), or it can contain a single layer of loose particles of gelling absorbent material . Alternatively, the layer 71 comprises a layer of particles intertwined between particles, which form a porous, macroscopic aggregate, as described in U.S. Patent Nos. 5,102,597 (Roe) and 5,180,622 (Berg). When the layers 71 contain a substantially pure layer of gelling absorbent material, it is important that the layer 71 remain permeable to liquids. It has been found that gelling absorbent materials, having a Gel Layer Permeability of at least 4 x 10"7 cm3 / s / g, can be advantageously used in layer 1. The value of PCG is an indication of the ability of the gelling absorbent material to maintain a permeable structure and to allow the transport of liquid through the layer of gelling absorbent material, even when wet.The test for measuring the PCG values have been described in detail in FIG. European application No. 93309614.1 Alternatively, the gelling absorbent material has an absorption-against-pressure (ACP) value of at least 23 g / g at a confining pressure of 5 kPa.A test for measuring ACP values has been described in European Patent Application No. 93909614.1 To determine the weight of the gelling absorbent material in the embodiment of Figure 9, in the middle anterior and middle posterior sections, 17 and 19, the total weight of the gelling absorbent material, in each section, comprises the gelling absorbent material present in both the 71 and 64 layers. The regions 13a and 13b, each containing about 20% by weight of the absorbent material of gelling in the core 3, the regions 13c and 13d, each containing 15% by weight, and the layer 71 containing 30% of the total weight of the gelling absorbent material in the layers 64 and 71.

The gelling absorbent material in layer 71 does not need X ---. having the same chemical and physical, or physical, properties as the gelling absorbent material in layer 64, but may have, for example, a lower rate of absorption or a lower absorption under pressure. In the embodiment shown in Figure 10, it is shown that the core 3 has a larger surface area in the rear middle section of the core 3 to provide an increased absorbent capacity. . In the following example, the rewet properties of a product according to the invention, will be determined and will be compared with the rewet properties of similar products, which do not have a greater part of the gelling absorbent material located in the later middle section . The determination of the average base capacity and the rewet test will be described below: Average Base Capacity: The average base capacity test measures the amounts of liquid absorbed per gram of the absorbent material in the central area of the absorbent structure, as indicated in Figure 11. First, the average base weight of the material, in the central area 6a - 6f, is determined in accordance with -. "Prüfmethode Nr. 1/93 MDS-HI Teil 1; Bestimmung der Flüssigkeitsaufnahme". The absorbent product is laid flat on a surface and the transverse center line 15 is marked, which is located midway between the front transverse edge 7 and the rear transverse edge 9, and which divides the absorbent core into the anterior mid section 17. and the posterior middle section 19. Also, the longitudinal center line 16 is marked. A total of up to 6 samples of / - test, 6a - 6f, each with a size of 100 x 100 mm are marked and cut from the absorbent product, as detailed in Figure 11. In the case of a smaller product size, the number of samples can be reduced. In any case, the samples are taken symmetrically around the transverse center line 15. Typically, each sample 6a-6f will be composed of absorbent material located between and contained by a sheet , upper 24 non-woven and a back sheet 26 impermeable to water, or external material. Samples 6a-6f are symmetrically removed around the transverse center line, above and below the transverse center line. The marked samples are removed with the help of a die or a laboratory cutter, and are weighed with a laboratory balance at an accuracy of 0.05 grams. For each sample, the dry weight, Wi. The samples were placed, one at a time, in a metal mesh basket 81, as shown in Figure 12, with the waterproof backing sheet 26, or backing material, placed upward. A methyl acrylate plate 82 is placed on top of the sample, and the metal mesh basket 81 is immersed in Jayco synthetic urine, whereby the sample and the methyl acrylate plate 82 were completely immersed for a period of time. 20 minutes. After 20 minutes, the basket containing the sample is immediately removed and placed on a ledge that allows the excess of the test solution to be easily drained. Immediately, a load of 10 kg is placed on top of the methyl acrylate plate, which lies on top of the sample, for a period of 2 minutes, so that a pressure of 100 g / cm2 is exerted. about the sample. After 2 minutes, the charge and the methyl acrylate plate are immediately removed and the sample is immediately weighed. The weight of each sample loaded with liquid was recorded, Wli. The average base capacity (g / g) for the previous middle section is given by: l / 3_ [(Wli-Wi) / Wi] [for samples i = 6d, 6e, 6f) i Similarly, the average base capacity can be determined for the later middle section, based on samples 6a, 6b and 6c.

* / "Rewet Test In the rewet test, the ability of an absorbent product to retain the liquids absorbed within the core is measured. In the rewet test, an absorbent diaper is selected, weighed and the elastic components either cut in half or removed to allow the product to be laid in its flattened position. / - The loading points, before and after, for the application of a test solution are clearly marked on the absorbent product. The above loading point is located on the longitudinal center line 16, at a distance of 10 cm from the front transverse edge 7 inwards towards the transverse center line 15. The rear loading point is located on the longitudinal center line 16, a a distance of 15 cm from the rear transverse edge 9 '"" - inward, towards the transverse center line 15. In separate tests, either the previous or the subsequent loading point is selected, and a typical volume of 240 ml of synthetic urine from Jayco, under conditions during use, of the chemical composition, as described in the previous text, was dripped on the loading point at a rate of 17 ml / sec. A circular load of 10 kg, and with a diameter of 16 cm and exerting a loading pressure of 50 g / cm2, was placed on the center of the load point during a period of 30 minutes. After 30 minutes, the load was carefully removed and dried, and eight (8) layers of pre-weighed filter papers (Eaton Dikeman 631, Nr 5) were placed immediately, centrally, over the load point and the weight moderately it was lowered, without delay, on the filter paper for exactly 30 seconds. The load and the filter paper were immediately removed after 30 seconds, and the difference in the weight of the filter paper was recorded as the first rewet value. A second set of eight (8) layers of pre-weighed filter paper was placed immediately, centrally, over the loading point and the weight was lowered moderately, without delay, onto the filter paper for exactly 30 seconds. The load and filter paper were removed immediately after 30 seconds and the difference in filter paper weight was recorded as the second rewet value. The total rewet is the sum of the two individual values of rewet, that is, rewet = lo. + 2nd. rewet values.

COMPARATIVE EXAMPLE In this example, three incontinence briefs, or diapers, were wetted in the anterior and posterior middle sections, and in each section the rewet values were measured. The average base capacity of the posterior middle section and the anterior middle section of each sample was determined by the method described above. The samples are similar in terms of their dimensions and capacity, and are representative of absorbent products typically used by adults suffering from strong incontinence. The following three products were compared: 1) An incontinence brief having an absorbent core according to the invention, for the "Medium" group of user size. 2) An incontinence brief, otherwise identical to), but with an absorbent core comprising more absorbent gelling material in the anterior mid section than in the posterior mid section, and 3) An incontinence brief commercially available under the brand name of Tena Super Slip (Art. ". * .__ No. 711200, manufactured by Mdlnlycke AB) in the" Medium "group of user size. The results of the rewet test and the absorptive capacity measurements of the previous products are presented in Table I, below. In Table I you can see "that for sample I, which has a higher amount of gelling absorbent material and a higher average base capacity in the middle section later., the rewet in the posterior middle section is smaller by a factor of approximately 10, compared to the rewetting of samples 2 and 3. Due to the low rewet values in the posterior middle section, samples 1 are specially adapted for use by users prostrate in bed. In the extended position, the liquid will be stored predominantly in the posterior middle section of the core. For bedridden users it is especially important to keep the rewet at a level as low as possible, to avoid a negative impact on the skin, moisture and pressures, which normally occur with incontinent users bedridden.

TABLE I Comparison of the average base capacity and the rewet values in the previous middle section and the posterior middle section, for three adult incontinence products. PARAMETER Sample 1 Sample 2 Sample 3 AbsorMaterial Material - Absorbent Gel Gelbent Product - Marketing Precleaning Pre-dominantly dispodominantly dominant in the mid-posterior mid section Product Dimensions Product length (mm) 838 838 805 Front width of the product (mm) 625 625 650 Rear width of the product (mm) 637 637 634 Absorbent structure Core length (mm) 651 651 636 Width of the center of the core (m) 200 200 175 Rear core width (mm) 325 325 330 Core front width (mm) 325 325 325 Total area of the nucleus (cm2) 1597 597 1580 (± 60) Total weight of the core (g) 103 103 110 (± 5) Previous Media Section Felt Air / Fibrous Material Area (cm2) 764 764 754 (± 50) Weight (g) 43.5 43.5 46 (± 3) Base weight (g / cm2) 0.056 0.056 0.062 Gelation absorbent material Area (cm2) 495 495 754 Weight (g) 4.5 7.5 6 (± 0.5) Base weight (g / cm2) 0.0091 0.015 0.008 Results of the Previous Average Test Average Base Capacity (g / g) 9.2 10.9 8.6 Re-wetting (g) 1.6 0.19 2.7 Posterior Media Section Air Felt Material / Fibrous area (cm2) 833 833 826 Weight (g) 47.5 47.5 51 (± 3) Base Weight (g / cm2) 0.056 0.056 0.062 Gel Absorbent Material Area (cm2) 495 495 826 Weight (g) 7.5 4.5 6 (± 0.5) Base Weight (g / cm2) 0.015 0.091 0.0073 Test Results of the Posterior Mean Average Base Capacity (g / g) 10.9 9.2 8.6 Rewet (g) 0.17 1.6 2.8 - *

Claims (19)

1. - An absorbent structure (3) comprising: - at least one layer (64) of fibrous or foamed absorbent material, - a perimeter (5) comprising a front transverse edge (7), a rear transverse edge (9) and two longitudinal sides (13,13 '), - * • - a transverse centerline (15) located midway between the front transverse edge (7) and the rear transverse edge (9), - a front midsection (17) located between the transverse center line (15) and the front transverse edge (7), and - a rear middle section (19) located between the transverse center line (15) and the rear transverse edge (9), and - absorbent material of gelation, characterized in that the weight of the gelling absorbent material located in the rear middle section (19) of the structure (3) is greater than the weight of the gelling absorbent material located in the front middle section (17) of the structure ( 3) .

2. An absorbent structure (3) according to claim 1, further characterized in that it lies between 55% and 100% by weight of the gelling absorbent material in the posterior middle section (19), preferably where between 60% and 100% by weight of the absorbent material. % and 90% by weight of the gelling absorbent material is located in the posterior middle section, and most preferably where between 65% and 80% of the gelling absorbent material is located in the posterior middle section (19).

3. An absorbent structure (3) according to claim 1 or 2, further characterized in that the weight of the fibrous or foamed absorbent material in the rear middle section (19) is greater than the weight of the fibrous or foamy absorbent material in the front middle section (17).

4. An absorbent structure (3) according to claim 3, further characterized in that between 55% and 100% by weight of the fibrous or foamed absorbent material is located in the posterior middle section (19), preferably where between the 60% and 90% by weight of the fibrous or foamy absorbent material is located in the rear middle section (19), and most preferably where between 65% and 80% of the fibrous or foamy absorbent material is located in the posterior middle section (19). ).

An absorbent structure (3) according to any of the preceding claims, further characterized in that the ratio of the average basis weight of the gelling absorbent material in the rear middle section (19) and in the front middle section (17) is between 1.1 and 3, preferably between 1.2 and 3 and most preferably between 1.3 and 3.

6. An absorbent structure (3) according to any of the previous claims, further characterized in that the ratio of the average base capacity of the posterior mid section (19) is greater than the average base capacity of the frontal middle section (17).

7. An absorbent structure (3) according to claim 6, further characterized in that the ratio of the average base capacity of the rear middle section (19) to the front mid section (17), is between 1.1 and 3, preferably between 1.2 and 3.

8. An absorbent structure (3) according to any of the previous claims, further characterized in that the ratio of the average basis weight of the fibrous or foamed absorbent material in the posterior middle section (19) and the front middle section (17) is between 1.1 and 3, preferably between 1.2 and 3, and most preferably between 1.3 and 3.

9. An absorbent structure (3) according to any of the previous claims, further characterized in that the structure comprises an acquisition / distribution layer (69) underlying the layer of absorbent material (64), the acquisition / distribution layer being located to a greater part of the posterior middle section (19) of the a absorbent structure (3).

10. An absorbent structure (3) according to claim 9, further characterized in that the acquisition / distribution layer (69) has a wet compression capacity of at least 5 cm3g "1 and a drip capacity of at least 10 g g" 1.

11. An absorbent structure (3) according to claim 9 or 10, further characterized in that the acquisition / distribution layer (69) comprises chemically hardened cellulosic fibers.

12. An absorbent structure (3) according to claim 9 or 10, further characterized in that the acquisition / distribution layer (69) comprises synthetic fibers bonded with air.

13. An absorbent structure (3) according to claim 9, 10, 11 or 12, further characterized in that the gelling absorbent material is located below and adjacent to the acquisition / distribution layer (69). .

An absorbent structure (3) according to claim 13, further characterized in that the basis weight of the gelling absorbent material which is located below and adjacent to the acquisition / distribution layer (69), is between 50 and 400 gr / m2.

15. An absorbent structure (3) according to any of the previous claims, further characterized by «that the length of the absorbent structure (3) is at least 50 cm.

16. An absorbent structure (3) according to any of the previous claims, further characterized in that the gelling absorbent material has an absorption against pressure of at least 23 g / g at a confining pressure of 5 kPa.

17. An absorbent structure (3) according to any of the preceding claims, further characterized in that the gelling absorbent material has a value of Gel Layer Permeability (PCG) greater than "4 x 10-7 cm3 / s / g.

18. An absorbent structure (3) according to any of the previous claims, further characterized in that the absorbent structure comprising a longitudinal center line (16), wherein the distance between a longitudinal side (13,13 ') and the line longitudinal center (16) increases substantially monotonically when going from the transverse center line (15) to the rear transverse edge (9).

19. An absorbent article (1) for use by adults and infants who walk prostrate in bed, comprising a liquid-impermeable backsheet (26) and a liquid-permeable top sheet (24) and an absorbent structure (3) of according to any of the preceding claims, interposed between the upper sheet (24) and the back sheet (26).