MXPA97000329A - Article absorb - Google Patents

Abstract

An absorbent article (1) comprises a relatively high absorbent capacity in the rear middle section (19) and liquid barrier means (37) between the transverse centerline (15) of the core (3), and the trailing edge (34) of waist of the backing sheet (26). By means of which the spill on the back of the absorbent article is reduced, and the product is especially adapted for incontinent users bedridden, ranging from babies who start walking to adult

Description

ABSORBENT ARTICLE / 'FIELD OF THE INVENTION The present invention relates to an absorbent article comprising a liquid permeable topsheet, a liquid impermeable backsheet and an absorbent core comprising a layer of absorbent material, interposed between the topsheet and the backsheet, the backing sheet comprising a perimeter having a front waist edge and a rear waist edge, the layer of absorbent material comprising: - a perimeter having two longitudinal edges, a front transverse edge and a rear transverse edge, - a center line cross section located midway between the front transverse edge and the rear transverse edge, - a mid-front section located between the transverse center line and the front transverse edge, and - a rear middle section located between the transverse centerline and the rear transverse edge .

BACKGROUND OF THE INVENTION In the technology of absorbent products, 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. Also, an attempt has been made to reduce spillage by providing barrier structures to the absorbent products to reduce the migration of liquid to and beyond the periphery of the absorbent product. From EP-A-052 413, it is known that for absorbent products, spillage of liquids along the edge of the waist can be avoided by providing a barrier sheet between the top sheet and the backsheet, and the ends of the absorbent article. The barrier sheet lies on the core at one end of the waist and prevents liquids from being compressed away from the transverse edges of the core. EP-A-376 022 (Robertson) discloses a waistband or waistband, wherein a unitary piece of elastomeric material extends from the perimeter of the waistband. ~ r absorbent product towards the core. The single piece of elastomeric material provides a waist elastic, as well as a straight barrier covering the top sheet at the waist end of the core. From the patent of E.U.A. No. 4,695,278 (Lawson) an absorbent article is known comprising a straight, elastic barrier fold in the leg areas. From the patent of E.U.A. No. 4,795,454 (Dragoo) an absorbent article is known which comprises a Straight, elastic barrier fold, which is connected with an edge close to an absorbent article, and is located near a packing fold. A liquid-permeable top sheet terminates inward of the near edge of the barrier fold. Seal means are located along the near end to prevent impregnation of liquids below the barrier fold. From EP-B-0 304 631 it is known to coat and seal side portions of the liquid-permeable topsheet with a hot melt adhesive to prevent lateral spillage of liquids. In the patent of E.U.A. 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 the patent of E.U.A. No. 4, 685,915, (Hasse) an absorbent product is described having a core comprising hydrophilic fibers and gelling absorbent material, 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 the patent of E.U.A. No. 4,834,735 (Alemany) discloses an absorbent core having a storage zone and an 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 top layer being substantially free of gelling absorbent material. 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 the patent of E.U.A. No. 4,411,660 (Dawn), an absorbent article is disclosed 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 ij 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 a absorbent product, which provides a small spill when used lying down. It is another object of the invention to provide an absorbent article that is specially adapted for users ranging from babies starting to walk to adults, especially women, when confined to a predominantly lying position. An absorbent article according to the invention is characterized in that the average base capacity of the absorbent material, located in the rear middle section of the absorbent material layer, is greater than the average base capacity of the absorbent material located in the front middle section of the absorbent material. cap. Liquid barrier means are located between the transverse center line of the layer and the back waist edge of the backsheet, to prevent liquids from spilling to the back waist edge of the backsheet. The average base capacity of the absorbent core depends on the amount and type of absorbent material that is used in the core and is a measurement for the amount of liquid that can be retained per gram of the absorbent material. The average base capacity is measured according to a test method, which is based on the official method established by Germany Medizinischer Dienst der Spitzenverbande der Kran en assen e.V. , for the reintegration of absorbent products for incontinence. The method of Test Prüfmethode Nr. 1/93 MDS-HI Teil 1, Besti mung der. - Flüssigkeitsaufnahme is found in the detailed description of the invention, which is presented below. 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. Since the rear middle section of the absorbent article is in a substantially horizontal position, when the user is lying down, most of the liquids that are discarded in this position will, due to the influence of gravity and the influence of the user's weight, be transported towards the posterior middle section. When the core reaches its saturation point, the relatively large quantities of liquids stored in the back of the absorbent core will cause the liquid to be compressed out of the rear transverse edge of the core.

Absorbent. To prevent spillage of liquids absorbed from the perimeter of the core towards the perimeter of the backsheet, the barrier means are placed between the traverse trailing edge of the core and the transverse waist edge of the backsheet. Another mechanism, by which spillage may occur in the posterior middle section, is via the topsheet of the absorbent article. To prevent spillage along the top sheet, the barrier means can be placed on the upper part of the absorbent core, in its posterior middle section. The advantage of said barrier structures is that liquid or other liquid or viscous waste is prevented from migrating along the upper sheet towards the rear transverse edge of the absorbent core. In one embodiment of an absorbent article, according to the present invention, the absorbent material may comprise only hydrophilic fibers such as lint pulp, rayon fibers or modified cellulose fibers, or may comprise a foam absorbent material as described in US patent No. 5,268,224 (Desmarais). The application of more absorbent material of this type in the middle rear section of the absorbent core can result in the so-called profiled core, which is of a larger caliber in the back part than in the front part. Alternatively, the absorbent core is compressed to a uniform gauge, so that the core density is higher in the back area. In a further embodiment of an absorbent article according to the invention, the core absorbent material comprises a gelling absorbent material. The gelling absorbent material can be mixed with the fibrous or foam material. Alternatively, the absorbent core may be composed only of gelling absorbent material, or may comprise layers of gelling absorbent material as described in European application No. 93309614.1. Preferably, the ratio of the average basis weight of the gelling absorbent material in the rear middle section and in the front middle section is between 1.1 and 3, preferably between 1.2 and 3 and most preferably between 1.3 and 3. The basis weight The average 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 the absorbent material is located. 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 an agent '' * dye 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 gelling absorbent material. The barrier means may comprise a strip of material impervious to the liquid, located below the top sheet. The strip covers a part of the core along the rear transverse edge of the core and is sealed in a liquid tightness in the backing sheet along a sealing line. Alternatively, the barrier means may comprise a liquid-impervious sealing area, such as a connection line between the topsheet and the backsheet, located between the rear transverse edge of the core and the back waist edge of the backsheet. back. The connection line can be a line of glue composed of a single line of glue, a pattern of spiral glue, as described in the patent of E.U.A. No. 4,098,632 (Sprague), or glue beads. Alternatively, the connecting line of the topsheet and the backsheet can be formed by fusing the topsheet to the backsheet, for example by crimping. Again, alternatively, the barrier means comprises a straight barrier fold having resilient means for separating the distant edge of the fold away from the top sheet. Again, in another embodiment, the barrier means comprises a section of the backsheet adjacent the rear edge of the waist that is bent to form a z-shaped fold. The combination of the increased average base capacity, in the rear middle section of the absorbent core and the barrier means, located near the rear waist region, make the absorbent article in accordance with s the invention, especially adapted for users prostrate in ( bed.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described in detail with reference to the accompanying drawings, in which: Figure 1 shows a front elevational view of an absorbent article according to the invention. Figures 2 to 5 show cross-sectional views of the core of the absorbent article of Figure 1, along the longitudinal center line. Figure 6 shows a front elevation view of an absorbent article comprising a backup protection. Figure 7 shows a cross-sectional view of the absorbent article of Figure 6 along the longitudinal central line. Figure 8 shows a front elevation view of an absorbent article comprising a straight barrier fold. Figures 9 and 10 show cross-sectional views of the absorbent article according to Figure 8, along the longitudinal center line. Figure 11 shows a front elevation view of the absorbent article, wherein the top sheet is connected to the backing sheet in a sealing area. r "Figures 12 and 13 show cross-sectional views of absorbent article of Figure 11, along the longitudinal center line, Figure 14 shows a front elevation view of an absorbent article having a topsheet comprising a Liquid impervious area Figure 15 shows a partial cross-sectional view of an absorbent article having a folded waist section as barrier means Figures 16 and 17 show cross-sections along the longitudinal centerline of the core of the absorbent article. absorbent article, according to the invention, the core comprising an acquisition / distribution layer Figure 18 schematically shows the region of the absorbent core for measuring the average base capacity of the A ^ core Figure 19 schematically shows the test equipment for measure the average base capacity of an absorbent structure Figure 20 schematically shows the Test equipment to determine the spill of liquid via the rear transverse edge of the core.

DETAILED DESCRIPTION OF THE INVENTION As used herein, the term "absorbent article" refers to devices, which absorb and contain exudates from the body, and, more specifically, refer to devices, which are placed against or close to the user's body to absorb and contain 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 a single use and, preferably to 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 worn by babies who start walking and incontinent people, which is used around the user's lower torso. In particular, the invention relates to an incontinence product, especially for adults, which can absorb between 100 and 1000 ml of liquids, preferably between 300 and 1000 ml. It should be understood, however, that the present invention is also applicable to other absorbent articles such as incontinence briefs, underwear for incontinent, supports and linings for diapers, and the like. Figure 1 shows an absorbent article 1, comprising 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 one embodiment of an article absorbent, 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 of area, or average basis weight, in the posterior mid section 19 is greater than in the mid-front section 17. Also, the modalities, where the average basis weight of the fibrous or foamy absorbent material is greater in the posterior middle section of the core absorbent 3, are inside of the scope of the invention. Preferably, the weight of the gelling absorbent material r is greater in the middle rear section of the core 3. In Figure 1, the absorbent article, or diaper 1, is shown in its non-contracted, flat state (i.e., with shrinkage). induced elastic pulled), with the portions of the article cut to show more clearly the construction of 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 display. 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. The back sheet 26 comprises a waist front edge 35 and a waist rear edge 40. Liquid barrier means 37 is placed between the transverse center line 15 of the core 3 and the waist rear edge 40 of the backsheet preferably between the rear transverse edge 9 of the core 3 and the waist rear edge 40 of the backing sheet. In the embodiment of Figure 1, the topsheet 24 and the backsheet 26 has length and width dimensions generally greater than those of the absorbent core 3. The topsheet 24 and the backsheet 26 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, the preferred diaper configurations are generally described in the US patent No. 3,860,003, entitled Contractable Side Portions for ^ ~ * Disposable Diaper (Disposable Side Slices for Disposable Diapers), which is issued to Kenneth B. Buell, January 14, 75; and the patent application of E.U.A. Series No. 07 / 715,152, granted, Absorbent Article With Dynamic Elastic Waist Feature Having a Predisposed Resilient Flexural Hinge, (Article Absorbent with a Elastic, Dynamic Accessory for the Waist, which Has a Hinge of Elastic Flex, Predisposed), Kenneth B. Buell et al., Filed 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 liquid absorbent materials 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). Nevertheless, 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 capable of 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. The absorbent structures Illustrative, to be used as the absorbent core 3, are described in the US patent. 4,610,678, entitled High-Density Absorbent Structures, issued to Weisman et al., September 9, 1986; patent of E.U.A. 4,673,402, entitled Absorbent Articles With Dual-Layered Cores, (Issued to Weisman et al., June 16, 1987; patent of E.U.A. 4,888,231, entitled Absorbent Core Having a Dusting Layer, issued to Angstadt on December 19, 1989; and patent of E.U.A. 4,834,735, entitled High Density Absorbent Members Having Lower Density and Lower Basis Weight Acquisition Zones (Alta Absorbent Members) Density of Lower Density Acquisition Areas and Lower Base Weight Acquisitions), 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 that it has 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 center line cross section 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. For example, the backsheet 26 can be secured to the absorbent core 3 by means of a continuous, uniform layer of adhesive, a molded layer of adhesive, or an arrangement of separate lines, coils or dots 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 a network of open-pattern, adhesive filaments, as described in U.S. Pat. No. 4,573,986, entitled Disposable Waste-Containely Garment, issued to Minetola et al. On March 4, 1986, most preferably several lines of adhesive filaments wound in a spiral pattern, as shown in FIG. illustrated by the apparatus and methods shown in the US patent No. 3,911,173, issued to Sprague, Jr., on October 7, 1975; patent of E.U.A. No. 4,785,996, issued to Ziecker et al., On November 22, 1978; and patent of E.U.A. 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 impermeable to liquids (e.g., urine), and is preferably manufactured to It can also be made from a thin plastic film, although other flexible, liquid-impermeable materials can also be used, as used herein, the flexible term refers to materials, which are condescending and will easily conform to The shape and general 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. 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, film-coated material Preferably, the backsheet is a thermoplastic film that it has a thickness of about 0.012 mm to about 0.051 mm. Particularly preferred materials for the lamina to backup 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 body of the absorbent core 3, and 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 attached 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 topsheet can be manufactured from a wide variety of materials, such as porous foams; cross-linked foams; plastic films with openings; or woven or non-woven 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 manufacturing techniques, which can be used to manufacture the topsheet 24. For example, the topsheet 24 can ^ - be a non-woven web of spunbonded, carded, wet-stretched, meltblown, hydroentangling, combinations of the above, or the like. 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 is manufactured by Veratec, Inc., a division of 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 bands for legs, side flaps, barrier folds, or elastic folds). The patent of E.U.A. 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 (binding fold). The patent of E.U.A. No. 4,909,803, entitled "Disposable Absorbent Article Having Elasticized Flaps" issued to Aziz et al., Lo. March 1990, describes a disposable diaper that has straight elastic flaps, (barrier folds), to improve the containment of the leg regions. The patent of E.U.A. No. 4,695,278 entitled Absorbent Article Having Dual Cuffs, issued to Lawson on September 22, 1987, discloses a disposable diaper having dual folds that include a tie fold and a barrier fold. The diaper 1 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 outwards from at least one of the waist edges of the core absorbent 3, and generally forms at least a portion of one of waist regions 56 or 58 of diaper 1. Disposable diapers are generally constructed in order to have two elastic waist accessories, 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. In addition, since the elastic waist accessory or any of its constituent elements may comprise a separate element secured to the diaper 1, the elastic waist accessory 34 is preferably constructed as an extension of other diaper elements, such as the backing sheet. 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 the US patent. No. 4,515,595, issued to Kievit et al., May 7, 1985, and the patent of E.U.A.

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 keep the diaper on the diaper. user. Fastening systems illustrative are described in the patent of E.U.A. No. 4,846,815, entitled "Disposable Diaper Having An Improved Fastening Device" (Disposable diaper having an improved fastening device), issued to Scrips, July 11, 1989; patent of E.U.A. No. 4,894,060, entitled Disposable Diaper With Improved Hook Fastener Portion (Disposable diaper with an improved portion of fastening by hook), issued to Nestegard, January 16, 1990; patent of E.U.A. No. 4,946,527, entitled Pressure-Sensitive Adhesive Fastener and Method of Making Same (Pressure-sensitive adhesive fastener and method for making same), issued to Battrell August 7, 1990; patent of E.U.A. No. 3,848,594, entitled Tape Fastening System for Disposable Diaper (Tape fastening system for disposable diaper), issued to Buell, on November 19, 1974; patent of E.U.A. Bl 4,662,875, entitled Absorbent Article (Absorbing Article), issued to Hirotsu and others, on May 5, 1987; and the patent application of E.U.A. 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 modality of j. Figure 2, the core 3 comprises fluff pulp of a uniform density. The caliber of section 13a is approximately 7 mm. The caliper in section 13b is approximately 10 mm, the caliper of section 13c is approximately 8 mm, and the caliper in section 13d 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 US Pat. No. 5,268,224 (Desmarais). The core 3 caliber, as shown in Figure 2, can be made uniform by "r" "calendering." This is illustrated in Figure 3. The core 3 of the 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 middle frontal and posterior 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 fibers, in the posterior middle section, improves fluid retention, 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 4 and 5, comprises a water-insoluble gelling absorbent material, which swells upon contact with liquids to form a hydrogel. Said materials are described, in detail, in the patent of E.U.A. No. Re. 32,649 (Brandt), and can absorb at least 20 times its own weight, of liquid. The hydrogel material may be in a particulate form, the particle sizes varying from 10 micrometers to 2000 micrometers, or may be in the form of flakes, fibers or sheets. The hydrogel material may also be composed of an interparticularly interlaced aggregate, as described in the U.S.A. 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 backing sheet. In the absorbent core of Figure 4, the gelling absorbent material is uniformly dispersed through the thickness, W, of each region I3a-l3d of layer 64. However, the gelling absorbent material may be present in different concentrations at through the thickness of the layer 64 of the core 3, and may be higher in those parts of the core that are further away from the user (those portions of the layer 64 that are located very close to the layer 63). Said cores with a so-called gradient of gelling absorbent material 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 about 25%, and the section 13b contains about 35% by weight of the total amount of the gelling absorbent material present in the layer 64. The section 13c can contain about 25% and the section 13d approximately 5% of the weight -_ total of the gelling absorbent material in the layer 64. Preferably, the gelling absorbent materials are materials of high resistance to gel formation. The particles of gelling absorbent material, which are highly resistant to gel formation, will undergo 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 a gel blockage. do not ""-* wanted. Suitable gelling absorbent materials have Gel Layer Permeability (PCG) values greater than 4 x 10-7 cm3 / s / g. The value of PCG can be measured by 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 foamy absorbent material typically can be "And around 0.05 g / m2. However, in addition to a variable basis weight of the gelling absorbent material for each section 13a-13d, the basis weight of the fibrous or foamed 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. Figure 6 shows an embodiment of the absorbent article 1, where barrier means 37 are formed by a strip of mial 38, also referred to as backup protection. The strip 38 is below the top sheet 24 along the rear transverse edge 9 of the core 3. Figure 7 shows a cross-sectional view of the article of Figure 6, along the longitudinal center line 16. mial strip 38 is preferably of a liquid impermeable mial, such as a polyethylene film, but can also be formed of a hydrophobic nonwoven mial. The strip 38 is connected to the backing sheet 26 along the sealing line 42, which can be formed by a fusion bonding, a glue line or spiral or ultrasonic bonding. The strip 38 prevents spillage of the rear transverse edge 9 of the core towards the waist rear edge 40 of the backsheet 26. In an alternative embodiment, the strip 38 can be loc on top of the top sheet 24. Figure 8 shows an absorbent article 1, wherein the barrier means 37 are formed by a barrier bend 39, straight, elastic. The barrier fold 39 comprises a strip of mial 44, which may be impermeable to liquid, or may be formed of a non-woven, air-permeable mial, such as spin-linked polypropylene fibers. The barrier fold 39 is with a near edge 41 sealingly connected to the absorbent article 1 along the sealing line 42. The barrier fold 39 is furthermore connected to article 1 in sealing areas 43, 43. The distal end 45 of the barrier fold 39 comprises an elastic mial 46, which, for example, has been applied to the distal edge in a prestretched form. The contraction of the elastic mial 46 separ the far edge 45 away from the topsheet 24. The invention of the barrier fold 39 is avoided by the sealing areas 43, 43, which fix the sides of the fold 39 against the absorbent article 1. Figures 9 and 10 show cross-sectional views of the absorbent article of Figure 8, along the longitudinal center line 16. The barrier fold 39, as shown in Figure 9, is loc between the rear transverse edge 9. of the core 3, and the waist rear edge 40 of the backing sheet 26. The near edge of the fold 39 is connected, in a sealed manner, to the backing sheet. The bend 39 not only prevents liquids from spilling from the rear transverse edge 9, from the core 3, towards the waist rear edge 40, from the backing sheet, but also from a liquid or solid waste barrier that migr to along the top sheet 24 towards the waist rear edge 40. In the absorbent article of Figure 10, the barrier fold 39 is loc on top of the topsheet 24. Although the liquids stored in the core 3 can pass below the barrier fold 39, the bend 39 isol the trailing edge 40 of the liquid and solid waste, which is not directly absorbed by the core, for example, large volumes of liquid that are very quickly discarded, or viscous debris, which can not be quickly taken up by the core 3. In addition to the barrier fold 39, an additional sealing line, or rear waist guard, may be loc between the waist rear edge 40 of the backsheet 26, and the rear transverse edge 9 of the core 3. In the absorbent article of Figure 11, the barrier means 37 are formed by sealing in area 43, wherein the topsheet 24 is sealed to the backsheet 26 in a liquid-tight manner. As shown in Figure 12, the barrier means comprises an area 43, wherein the topsheet 24 is fused to the backsheet 26 by crimping. Alternatively, a waist elastic band 47 may be in the barrier means, the top sheet 24 being connected to the back sheet 26 via the waist elastic band 47. This is shown in Figure 13. Figure 14 shows an absorbent article, wherein the topsheet 24 comprises a liquid permeable area 48, located on the absorbent core 3, which has been indicated by shading. Outside the area 48, the topsheet is impermeable to liquid and is connected to the backsheet 26 along the periphery of the topsheet. In addition to the sealing connection of the periphery of the topsheet 24 to the periphery of the backsheet 26, a sealing area 43 may be comprised between the rear transverse edge 9 and waist rear edge 40, although this sealing area may be omitted. The topsheet may be composed of a film or film and fiber film unit, and may be partially perforated in the central area 48. A suitable material for said top sheet is, for example, a top sheet as used in the pantyhose. ALWAYS protectors, made by Procter & Gamble Company, Alternatively, a coating, hydrophobic or liquid impervious, may be applied to the inner or outer surface of the topsheet 24 outside the liquid permeable areas 48. Figure 15 shows one embodiment, wherein a later section of waist of the backing sheet 26 can be folded into a fold 55 in z-shaped. The rear waist section comprises a first section 51, which is bent inwardly on the topsheet 24 and is attached to the topsheet by attachment means 54, which may be an ultrasonic joint, splice joints, or an adhesive connection. The rear waist section 52 of the backing sheet 26 is folded outwards to along a fold line 53, and is stuck in a bent position on the section 51. Figure 16 shows an embodiment of an absorbent core 3 and comprises an acquisition / distribution layer. 69, located in the upper part of the layer 64 of the core 3. The acquisition / distribution layer serves to rapidly 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 basis 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. Pat. 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 the application of E.U.A. 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 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 cmg "1 and a drip capacity of at least 10 g g" 1 can be successfully used in the acquisition / distribution layer 69.

The wet compression capacity 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 for synthetic urine is: 2.0 g /: KCl; 2.0 g / 1 Na2SO4; 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 spread. The gauze completely covers the forming screen and makes curves on its sides to prevent fluff 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 30 g portion of lint is added to the sample chamber in the pad-forming machine, in small quantities, via a sample feed and without obstructing the machine blades. 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 is placed on top.

A steel load, with dimensions of about 35.6 cm x 35.6 cm x 2.5 cm, weighing approximately 16.3 kg, is placed on the top of the pad for approximately 120 seconds, or longer, until the pad is necessary 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 to * "* - **. ' 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-making machine to make sample pads It is not intended to be limiting.Any suitable method can be used, provided that it obtains a consistent and homogeneous lint template, which is then compressed 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. The pad was then densified under a load of 3.6 kg / cm 2, for reasons of pad integrity, using a Carver laboratory press The pad thickness was measured and its fiber density was calculated by 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 higher load balance that has a 0.01 g sensitivity Synthetic urine is slowly dispensed onto the pad until the target wet weight is obtained, as measured by the equilibrium.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 . 2cm) and corresponding to a pressure of 77 g / cm "2, it 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 registered using calibrators The Compression Capacity in Humid 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 pad (cm2)) - (dry weight of pad (g) / fiber density (g / cm2) ) wet compressive capacity = hollow volume per gram = [(thickness of pad under load (cm) x area of pad (cm2)) - (dry weight of pad (g) / fiber density (g / cm " 3)] + dry weight of the pad (g), wherein the density of the fiber is calculated 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 was again 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, USA), towards the center of the sample pad at a speed of 5 + 0.25 ml / s "1 The time for the pad was recorded to release the first drop of synthetic urine through the bottom of the pad and into the drip tray.The pump is immediately stopped then this happens. The time recorded and the pumping speed are then used to calculate the volume (ml) of synthetic urine absorbed by the sample upon saturation, ie when the sample begins to drip. The balance can be used to check this periodically, thus minimizing any variation in the pump that 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) In the embodiment of Figures 16 and 17, the acquisition / distribution layer 69 has a generally rectangular shape and it 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 center line 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 part 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 layer _, "Acquisition / distribution, located in the rear 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 17, a layer 71 Extra of gelling absorbent material is located below the acquisition / distribution layer 69. This layer of gelling absorbent material serves to quickly drain the layer 69, so that it is ready for subsequent liquid jets, and maintains a dry pH regulator adjacent 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 forces frictional, as described in the patent of E.U.A. No. 4,600,458 (Kramer), or may 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 the U.S. Patents. 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 for 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 the European patent application No. 93909614.1 To determine the weight of the absorbent material of and gelation in the embodiment of Figure 17, in the middle anterior and medial 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 contain about 20% by weight of the gelling absorbent material 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 layers 64 and 71. The gelling absorbent material in layer 71 does not need to have the same chemical and physical, or physical, properties as the gelling absorbent material in layer 64, but may have , for example, a lower absorption speed or a lower absorption under pressure. In the following example, the rewetting properties of a product having an absorbent core comprising a later middle section, which has a high average base capacity, will be determined and compared with the rewet properties of similar products, which do not have a greater part of the gelling absorbent material located in the posterior middle section. Next, the effect of the liquid barrier means will be measured in a runoff test. The determination of the average base capacity, the rewet test and the runoff test will be described then: Average Base Capacity: The average base capacity test measures the amounts of liquid absorbed per gram of the absorbent material in the central area 6a- 6f of the absorbent core, as indicated in Figure 18. First, the average basis 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 rear middle section 19. Also, the longitudinal center line 16 is marked. A total of up to 6 test samples, 6a-6f, each with a size of 100 x 100 mm are marked and cut off from the absorbent product, as shown in FIG. detailed in Figure 18. 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 centerline 15. Typically, each sample 6a-6f will be composed of absorbent material located between and contained by a nonwoven upper sheet 24 and a back sheet 26 impermeable to water, or external material. Samples 6a-6f are symmetrically removed around the transverse centerline, 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 19, 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. r 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 posterior 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, anterior and posterior, 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 inwards, towards the transverse centerline 15. In separate tests, either the previous or the subsequent loading point is selected, and a typical volume . of 240 ml of Jayco synthetic urine, 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 were immediately placed (8) / *. layers of pre-weighed filter papers (Eaton Dikeman 631, Nr 5), centrally, over the loading point and the weight moderately 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, in , central shape, on the loading point and the weight was lowered moderately, without delay, on 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. r ,. Run-off Test The run-off test method is used to test the effectiveness of the barrier means, such as backup protection 38, as shown in Figures 7 and 8. The test simulates, under typical conditions of use for people who suffer from incontinence during the night or when lying down, where the absorbent material located in the rear half of the product under a large or repeated load potentially saturates leading to the spill. The mechanism of such spill can be either through extrusion of pressure (via body movement) or simple capillary action, so that urine can not be adequately retained within the core region, is absorbed by clothing of the user or the sheets. The test is performed using an apparatus, as detailed in Figure 20. The absorbent product is selected f and the leg elastics are either cut or removed to facilitate the flat placement of the product on a work surface. The loading point 85, located along the longitudinal center line 16 of the product, at a distance of 10 cm from the rear transverse edge 9 of the core 3, is marked on the absorbent product. The absorbent product 1 of the test is then laid flat and fastened on a support 83, which is mounted on a platform 84 of adjustable height at an angle 45% to platform 84. A stack 86 of 10 sheets of folded gauze (150 cm x 12.5 cm), BOUNTY, manufactured by The Procter & Gamble Company, weighing approximately 35 grams, is placed in the waist rear region 58 of the absorbent product 1, at a distance of 8 mm from the rear transverse edge 9 of the core 3. A volume of 250 ml synthetic urine from Jayco, with a composition as detailed above was added to a pump flask 87. All the / volume of the 250 ml of synthetic urine was dispensed onto the test product from a height of 5 mm above the loading point 85 at a rate of 40 ml / min, in order to simulate a single heavy jet of load. Synthetic urine not properly acquired and absorbed at the time, available by the absorbent core 3, is typically extruded under the combined force of gravity and / or capillary action through, and is collected by / * _. the pile of absorbent towels 86 or is contained by the waist protection 38. The gauzes 86 are weighed both before and after a period of 5 minutes after the cessation of the jet. The difference was recorded as runoff.

COMPARATIVE EXAMPLE 1 In this example, three incontinence briefs were moistened in the anterior and posterior middle sections, or diapers, 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:, /, l) An incontinence brief having an absorbent core according to the invention, for the user size Medium group. 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 Molnlycke AB) in the Medium size user group. The results of the rewet test and the absorptive capacity measurements of the previous products are presented in Table I, below. In Table I, it can be seen that for sample I, which has a greater amount of gelling absorbent material and a base capacity in the posterior middle section.

At higher average, 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 used by bedridden users. In the extended position, the liquid will be stored predominantly in the posterior middle section of the core. For the users In bed, it is especially important to keep the rewet at a level as low as possible, to avoid a negative impact on the skin, humidity and pressures, which normally occur with incontinent users bedridden. TABLE I Comparison of average base capacity and rewet values in the previous middle section and the posterior r-i-media section, for three adult incontinence products. PARAMETER Sample 1 Sample 2 Sample 3 AbsorMaterial Material AbsorProduct of Gelí- Gelification Gel- Precleaning Predominantly dominantly available in the mid-posterior 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 Core center width (mm) 200 200 175 Core rear width (mm) 325 325 330 Core front width (mm) 325 325 325 Total core area (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 Absorbent aelification 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 Test Results of the Previous Average Average Base Capacity (g / g) 9.2 10.9 8.6 ? Wetting (g) 1.6 0.19 2.7 Posterior Media Section Felt Air / Fibrous Material Area (cm2) 833 833 826 Weight (g) 47.5 47.5 5103) Base Weight (g / cm2) 0.056 0.056 0.062 -. VIATERIAL Absorbent Gelification Area (cm2) 495 495 826 Weight (g) 7.5 4.5 6 (3: 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 COMPARATIVE EXAMPLE II In the following comparative example, three products indicated in Table II were compared as sample 4, sample 5 and sample 6. Sample 4 is a product similar to sample 1 in the first comparative example, but is provided with barrier means against the liquid of the type shown in Figure 7. Sample 5 is a product identical to the iestra 1 in comparative example 1, and sample 6 is a product identical to sample 3 in comparative example l. In Table II it can be seen that for sample 5 the liquid runoff was reduced by a factor of 2, compared to the liquid runoff of sample 6. This is caused by the presence of an increased amount of absorbent material in the sample. the rear middle section of sample 5. However, the amount of gelling absorbent material can not be increased as well, since at higher concentrations a gel block will occur. Also, for reasons of cost, the amount of gelling absorbent material, in the later middle section, can not be increased either. Therefore, the liquid runoff can not be completely avoided by increasing the amount of gelling absorbent material in the rear middle section. As illustrated. or sample 4, the addition of liquid barrier means can further reduce runoff to a negligible level. The reduction of runoff, or spill in the back waist section of the absorbent product is especially important for those products that are used by bedridden patients, for whom the combination of pressure and humidity can lead to a skin damaging condition .

TABLE II Comparison of runoff values for three adult incontinence products. PARAMETER Sample 4 Sample 5 Sample 6 AbsorMaterial Material AbsorProduct of Geli-Comerc Gelbent Alcifi cation Preli- cation Predominantly dominantly nible without section in section Protector medium posterior posterior middle waist with protector without waist waist protector 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 core center (mm) 200 200 175 Rear width of the core (mm) 325 325 330 Front width of the core (mm) 325 325 325 Total area of the nucleus (cm2) 1597 1597 1580 (± 60) Total weight of the core (g) 103 103 110 (± 5! Previous Medium Section Air Diffuser / Fibrous Material A "ea (cm2) 764 764 754 (^ 50) Weight (g) 43.5 43.5 46 (± 3) Base weight (g / cm2) 0.056 0.056 0.062 Absorbent aelification 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 Test Results of the Previous Average Average Base Capacity (g / g) 9.2 10.9 8.6 Rear Middle 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 Gelification Absorbing 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 Runoff (g) zero 17.5 33.6

Claims (15)

1. - An absorbent article (1) comprising a liquid-permeable upper sheet (24), a liquid-impermeable backing sheet (26) and an absorbent core (3), interposed between the upper sheet and the backing sheet; the backing sheet comprises a perimeter having a waist leading edge (39) and a trailing edge (40) of waist, the core (3) comprises a layer (64) of absorbent material, said layer (64) comprises: - a perimeter having two longitudinal edges (13, 13), a transverse leading edge (7) and a transverse rear edge (9), - a transverse center line (15) located midway between the transverse leading edge (7) and the trailing trailing edge (9). - a front middle section (17) located between the transverse center line A (15) and the transverse front edge (7) and - a rear middle section (19) located between the transverse center line (15) and the transverse rear edge ( 9), characterized in that the average base capacity of the absorbent material, located in the anterior middle section (17) of the layer (64), is smaller than the average base capacity of the absorbent material located in the posterior middle section (19) of the layer (64), liquid barrier means (37, 38, 39, 43, "y5) being located between the transverse centerline (15) of the layer (64) and the rear edge (40) of the backing sheet (26) to prevent liquids from spilling toward" the trailing edge 40 of waist of the backing sheet (26).

2. An absorbent article (1) according to claim 1, further characterized in that the ratio of the average base capacity of the posterior middle section (19) to the average base capacity of the previous middle section (17) is between 1.1 and 3, preferably between 1.2 and 3.

3. An absorbent article (1) according to claim 1 or 2, further characterized in that between 55% and 100% by weight of the gelling absorbent material is located in the section rear half (19), preferably between 60% and 90% by weight of the gelling absorbent material is located in the posterior middle section and very '^ preferably between 65% and 80% by weight of the gelling absorbent material is located in the posterior middle section (19).

4. An absorbent article (1) according to any of the previous claims, further characterized in that the ratio of the average basis weight of the gelling absorbent material in the posterior middle section (19) and in the anterior middle section (17) is between 1.1 and 3, preferably between 1.2 and 3 and most preferably from O? Tre 1.3 and 3.

5. An absorbent article (1) 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 in the anterior middle section (17), it is between 1.1 and 3, preferably between 1.2 and 3, and most preferably between 1.3 and 3.

6. An absorbent article (1) according to claim 1, characterized in addition, because the barrier means (37, 38, 39, 43, 55) are located between the transverse rear edge (9) of the layer of absorbent material (64) and the rear edge (40) of the backing sheet. (26) to prevent spillage of liquids from the trailing trailing edge (9) towards the trailing edge (40) of the waist.

7. An absorbent article (1) according to any of the previous claims, further characterized in that the barrier means (37, 38, 39, 43, 55) comprise a sealing area (43) impervious to liquid, which is extends along at least a part of the length of the transverse trailing edge (9) of the layer of absorbent material (64), the topsheet (24) and the backsheet (26) being joined in the area of sealed (43).

8. - An absorbent article (1) according to claim 7, further characterized in that the sheet Higher (24) is joined with heat to the backing sheet (26).

9. - An absorbent article (1) according to claim 7, further characterized in that the upper sheet (24) is adhesively connected to the backing sheet (26) in the sealing area (43).

10. An absorbent article (1) according to any of the previous claims, further characterized in that the upper sheet (24) is impervious to liquid in the area of the upper sheet extending beyond the transverse rear edge (9) of the layer of absorbent material (64).

11. An absorbent article (1) according to any of the previous claims, further characterized in that the backsheet (26) comprises a rear waist section extending beyond the transverse rear edge (9) of the layer of absorbent material (64), wherein the rear waist section comprises a z-type inward fold (55), which forms the liquid barrier means, the inward fold (55) comprises an inner section (51) and a cross-section outer (52), the inner section (51) and the outer section (52) being mutually connected along a fold line (53), located near the trailing trailing edge (9) of the layer (64), and fixing means (54) joining the fold line (53) to the upper sheet (24) and joining the outer section J 2) to the inner section (51).

12. An absorbent article (1) according to any of the previous claims, further characterized in that an elastic material (47) is comprised between the transverse rear edge (9) of the layer (64) and the trailing edge (40) of waist of the backing sheet (26).

13. An absorbent article (1) according to claim 12, further characterized in that the material The elastic is located in the sealing area (43), the upper sheet (24) being connected to the backing sheet (26) via the elastic material.

14. An absorbent article (1) according to any of the previous claims, further characterized in that the barrier means (37, 38, 39, 43, 55) comprise a straight barrier fold (39) comprising a near edge (41), which is connected to the absorbent article, and a distant edge (45) comprising elasticity means (46) for separating the distant edge (45) away from the upper sheet (24).

15. An absorbent article (1) according to claim 13, further characterized in that the near edge (41) is located between the transverse rear edge (9) of the layer (64) and the transverse waist edge (40) of the backing sheet (26).