MXPA00009181A

MXPA00009181A - Fluted composite and related absorbent articles

Info

Publication number: MXPA00009181A
Application number: MXPA/A/2000/009181A
Authority: MX
Inventors: Peter A Graef; Clifford R Bolstad; Fred B Howard; David G Unrau; David G Marsh; Charles E Miller; Andre S Hajnal
Original assignee: Clifford R Bolstad; Peter A Graef; Andre S Hajnal; Fred B Howard; David G Marsh; Charles E Miller; David G Unrau; Weyerhaeuser Company
Priority date: 1998-03-19
Filing date: 2000-09-19
Publication date: 2001-07-31

Abstract

An absorbent composite (10) that includes a fibrous matrix having absorbent material dispersed in bands (12) along the composite's length is disclosed. The bands define liquid distribution zones (14). On liquid contact, absorbent material material swelling occurs and produces a wetted composite having flutes that include swollen absorbent material separated by distribution zones (14), regions of the composite that are substantially free of absorbent material. Absorbent articles that include the composite are also disclosed.

Description

MIXED RETICULATED MATERIAL AND RELATED ABSORBENT ITEMS FIELD OF THE INVENTION The present invention relates to a mixed absorbent material and absorbent articles that include the mixed material. The mixed absorbent material is a crosslinked absorbent mixed material that includes superabsorbent material.

BACKGROUND OF THE INVENTION Cellulose fibers derived from wood pulp are used in a variety of absorbent articles, for example, diapers, incontinence products and feminine hygiene products. It is desirable that the absorbent articles have a high liquid absorbing capacity, rapid liquid capture, reduced rewetting, as well as having good dry and wet strength characteristics to obtain durability during use and efficient fluid handling. The absorbent capacity of articles made of cellulose fibers is often improved by the addition of superabsorbent materials, such as superabsorbent polymers. The superabsorbent polymers known in the art have the ability to absorb liquids in amounts of 5 to 100 times or more their weight. In this way, the presence of superabsorbent polymers greatly increases the liquid retention capacity in the absorbent articles made of cellulose. Because the superabsorbent polymers absorb liquid and expand after coming into contact with it, superabsorbent polymers have hitherto mainly been incorporated into cellulose mats which are produced by conventional methods of dry air deposition. The processes of wet deposition to form cellulose mats have not been used commercially because the superabsorbent polymers tend to absorb liquid and expand during the formation of the absorbent mats, thus requiring significant energy for complete drying. The cellulose structures formed by the wet deposition process typically exhibit certain properties that are superior to those of an air deposition structure. The characteristics of integrity, fluid distribution and absorption of the cellulosic structures deposited in the wet are superior to those of the structures deposited in the air. Attempts to combine the advantages of wet-laid mixed materials with the high absorbent capacity of superabsorbent materials have led to the formation of various wet-deposited absorbent materials including superabsorbent materials. Generally, these structures can be characterized as structures that either have superabsorbent polymers distributed on the surface of a mixed air-laid material, laminates, or alternatively, structures having superabsorbent material distributed relatively uniformly throughout of the mixed material. However, mixed materials containing superabsorbent materials are commonly susceptible to gel blocking. After absorption of liquid, the superabsorbent materials tend to coalesce and form gelatinous masses that impede the absorption of liquid into unmoistened potions of the mixed material. By preventing the distribution of the liquid acquired from the non-moistened portions of the mixed material, gel blocking precludes the efficient and efficient use of the superabsorbent materials in fibrous mixed materials. The absorption capacity of said conventional fibrous composite materials including relatively homogeneous distributions of superabsorbent material is significantly restricted after the initial discharge of liquid. The diminished capacity of said mixed fibrous materials results from the narrowing of the capillary catchment and the distribution channels that accompany the swelling of the superabsorbent material. The diminution of the absorbent capacity and the concomitant loss of the capillary channels of distribution by conventional absorbent cores that include superabsorbent material, are manifested by decreased liquid uptake regimes, and are far from the ideal liquid distribution during successive liquid discharges. Accordingly, there is a need for methods for forming a mixed absorbent material which includes superabsorbent material and which efficiently acquires and absorbs liquid along the mixed material, and which distributes the acquired liquid to the absorbent material, where the liquid is absorbed and retained effectively without gel blocking. There is also a need for a mixed absorbent material that continues to acquire and distribute liquid throughout the mixed material in successive discharges of liquid. In addition, there is a need for a mixed absorbent material containing superabsorbent materials which has the advantages associated with mixed wet deposition materials, including wet strength, absorption and pick up capacity, liquid distribution, softness and elasticity. The present invention seeks to satisfy these needs and provides other related advantages.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a fibrous absorbent composite material containing dispersed absorbent material through the mixed material and along the length of said mixed material. After rewetting, the liquid captured by the mixed material is distributed along the mixed material and finally absorbed by the absorbent material of the mixed material. In one embodiment, the absorbent material is dispersed in bands across the length of the mixed material. For such embodiment, the absorbent material swells with the captured liquid and the portion of the mixed material including the absorbent material expands and rises from the moistened surface of the mixed material to form channels or lattices. The cross-linked structure of the wetted mixed material increases the absorption, uptake and distribution of liquid in subsequent discharges of liquid. In another aspect of the invention, absorbent articles are provided that include the crosslinked mixed material. Absorbent articles include absorbent products for consumer use, such as diapers, feminine hygiene products and adult incontinence products.

BRIEF DESCRIPTION OF THE DRAWINGS The above aspects and many of the concomitant advantages of this invention will be more readily appreciated in connection with the following detailed description, considered in conjunction with the accompanying drawings, in which: Figure 1 is a top view of a representative mixed material formed in accordance with with the present invention; Figure 2A is a cross-sectional view of a representative mixed material of the present invention in a dry state; Figure 2B is a cross-sectional view of a representative mixed material of the present invention in a moistened state; Figure 2C is a perspective view of the moistened mixed material shown in Figure 2B; Figure 3 is a cross-sectional view of a representative mixed material formed in accordance with the present invention; Figure 4A is a perspective view of the upper surface of a representative mixed material formed in accordance with the present invention; Figure 4B is a perspective view of the bottom surface of a representative mixed material formed in accordance with the present invention; Figure 5 is a perspective view of a stripe pattern of the representative absorbent material formed in accordance with the present invention; Figure 6 is a perspective view of another stripe pattern of the representative absorbent material formed in accordance with the present invention; Figure 7 is a perspective view of another stripe pattern of the representative absorbent material formed in accordance with the present invention; Figure 8 is a microphotograph (15X amplification) of a portion of a representative mixed material formed in accordance with the present invention, the microphotograph showing a machine direction view of a cut in the machine direction through an enriched region with absorbent material, Figure 9 is a microphotograph (15X amplification) of a portion of a representative mixed material formed in accordance with the present invention, the microphotograph showing a view in the machine direction of a cut in the direction against the machine through from a liquid distribution zone; Figure 10 is a microphotograph (15X amplification) of a portion of a representative mixed material formed in accordance with the present invention, the microphotograph showing a view in the machine direction of a cut in the direction against the machine through a region of interface of the mixed material between a liquid distribution zone and a region enriched with absorbent material; Figure 11A is a perspective view of another representative mixed material according to the present invention; Figure 11B is a perspective view of an absorbent structure composed of the mixed material shown in Figure 11A and a catchment layer; Figure 12A is a schematic view illustrating a device and method for forming the mixed material of the present invention; Figure 12B is a top plan view of a device for forming the mixed material of the present invention; Fig. 13 is a schematic view illustrating a double wire device and a method for forming the mixed material of the present invention; Figures 14A-14H are cross-sectional views of representative mixed materials formed in accordance with the present invention; Figure 15 is a schematic view illustrating a representative headbox assembly and a method for forming the composite material of the present invention; Figure 16 is a schematic view illustrating a representative headbox assembly and a method for forming the composite material of the present invention; Figure 17 is a view illustrating representative ducts for introducing absorbent material into a fibrous web according to the present invention; Figure 18 is a cross-sectional view of a portion of a component of an absorbent article incorporating a representative mixed material formed in accordance with the present invention; Figure 19 is a cross-sectional view of a portion of a component of an absorbent article incorporating a representative mixed material formed in accordance with the present invention; Figure 20 is a cross-sectional view of a portion of an absorbent structure incorporating a storage layer and a representative mixed material formed in accordance with the present invention; Figure 21 is a cross-sectional view of a portion of an absorbent structure incorporating a storage layer and a representative mixed material formed in accordance with the present invention; Figure 22 is a cross-sectional view of a portion of an absorbent structure incorporating a storage layer, a capture layer and a representative mixed material formed in accordance with the present invention; Figure 23 is a cross-sectional view of a portion of an absorbent structure incorporating a storage layer and a representative mixed material formed in accordance with the present invention; Figures 24A-24D are cross-sectional views of a portion of absorbent structures incorporating a representative mixed material formed in accordance with the present invention; Figures 25A-25H are cross-sectional views of a portion of absorbent articles incorporating a representative mixed material formed in accordance with the present invention; Figure 26A is a cross-sectional view of a portion of an absorbent article incorporating a representative mixed material formed in accordance with the present invention; Figure 26B is a cross-sectional view of a preferred embodiment of an absorbent article incorporating a liquid permeable lining sheet, a liquid impermeable backing sheet and a representative mixed material formed in accordance with the present invention; Figure 27 is a cross-sectional view of a portion of an absorbent article formed in accordance with the present invention; Figure 28 is a cross-sectional view of a portion of an absorbent article formed in accordance with the present invention; and Fig. 29 is a cross-sectional view of a portion of an absorbent article formed in accordance with the present invention. Figures 30A and 30B are top plan views of representative mixed materials formed in accordance with the present invention (A means the machine direction of the mixed material).

DETAILED DESCRIPTION OF THE PREFERRED MODALITY The mixed absorbent material of the present invention fibrous composite material including absorbent material. The mixed absorbent material includes a fibrous matrix having absorbent material dispersed in strips along the mixed material. Between the bands of the mixed material of absorbent material lie distribution zones composed mainly of fibers. Generally, the absorbent material serves to absorb and retain the liquid acquired by the mixed material. The fibrous distribution zones of the mixed material serve to capture the liquid that makes contact with the mixed material and to distribute the liquid acquired along the mixed material and finally to the absorbent material. The mixed absorbent material can advantageously be incorporated into various absorbent articles such as diapers, including disposable diapers and training pants; feminine care products that include sanitary napkins, panty liners; adult incontinence products, towel fabrics; dental and surgical sponges; bandages; pads for food trays; and similar. Because the mixed material is highly absorbent, the mixed material can be included in an absorbent article as a liquid storage core. In such a structure, the mixed material can be combined with one or more other mixed materials or layers including, for example, an acquisition and / or distribution layer. Alternatively, since the mixed material can quickly acquire, distribute and store liquid, the mixed material can be effectively incorporated into an absorbent article as the sole absorbent component without including other individual layers such as acquisition and / or distribution layers. In a preferred embodiment, the present invention provides an absorbent article such as a diaper, which includes a crosslinked absorbent mixed material having a liquid permeable lining sheet and a reinforcing sheet impervious thereto. Due to the ability of the mixed material to rapidly acquire and distribute the liquid, the mixed material can serve as a liquid handling layer that acquires and transfers a portion of the acquired liquid to an underlying storage core. Thus, in another embodiment, the mixed absorbent material can be combined with a storage core to provide an absorbent core that is useful in absorbent articles. The mixed absorbent material of the present invention is a mixed cross-linked storage material. As used herein, the term "lattice" refers to the nature of the mixed material, which upon being wetted, develops channels or lattices as a result of the expansion of the absorbent material. As indicated above, the absorbent material is located in strips or strips placed across the width of the mixed material and extends in strips along the length of the mixed material. Upon contact with the liquid acquired by the fibrous composite material, a swelling of the absorbent material occurs and produces a wetted mixed material having channels or lattices that include a swollen absorbent material separated by zones or distribution channels, and the regions of the mixed material which are generally substantially free of absorbent material. The crosslinked mixed material of the present invention is a fibrous structure prepared from cellulosic fibers which have been moistened during the forming process and, as a result they provide a fibrous mixed material in which the fibers are joined. As used in this context, the term "bound" refers to the hydrogen bond that occurs between fibers that have been wetted and then formed into a mesh or mesh. The bond that occurs between the wetted fibers that have subsequently been formed into a fibrous mesh results in a mesh having structural integrity as well as increased strength, both wet and dry, compared to air-laid meshes. Fibrous meshes formed from wetted fibers have a significantly higher strength and integrity than fibrous meshes with air deposition formed from dry fibers, which are unable to undergo any significant inter-fiber bonding. The simple proximity of the dry fibers in a fibrous mesh is not sufficient to provide any significant bond between the fibers. Consequently, and as is already known, fibrous webs of air deposition generally lack wet or dry strength. In addition to standard wet deposition processes, fibers wetted and formed into fibrous meshes can be produced by foaming processes. The band forming nature of the cross-linked absorbent composite material is illustrated in Figures 1-3. With reference to Figure 1, a cross-linked representative cross-linked absorbent material generally indicated with reference 10, formed in accordance with the present invention, includes regions 12 enriched with absorbent material (i.e., liquid storage areas) and fibrous regions 14 which they are substantially free of absorbent material (i.e., liquid distribution zones). The regions 12 enriched with absorbent material are generally fibrous regions to which absorbent material has been added. When the mixed absorbent material contacts the liquid, the liquid is rapidly acquired by the predominantly fibrous regions of the mixed material. The fibrous regions are relatively open and porous in nature and promote rapid uptake, penetration and distribution of the liquid. The liquid acquired by the mixed material generally travels longitudinally through the mixed fibrous material along the length of the mixed material through the distribution zones (i.e., regions 14) and is absorbed by regions of the mixed material enriched with material absorbent (ie, regions 12). The acquired liquid is absorbed laterally in the absorbent material, as the liquid is distributed along the length of the mixed material. For the crosslinked mixed material, the successive liquid discharges are absorbed at a speed greater than the speed for the initial discharge through the establishment of grids and channels in the discharge of the initial liquid. Upon wetting, the mixed material of the present invention is converted into a crosslinked structure having channels to rapidly acquire additional liquid and distribute the liquid to sites that are remote for discharge. The uptake of the liquid by the absorbent material leads to the expansion and increase of gaps in the fibrous structure. For the reticuted mixed material, the collection times for the subsequent discharge of liquid are less than the times of the initial collection. Generally, reduced uptake times of successive liquid discharges are not observed for conventional absorbent structures. Since conventional absorbent structures can not form a cross-linked structure and therefore lack channels to distribute additional liquid, collection times for these structures generally increase for successive discharges of liquid. The increased uptake time is attributed to the fact that the liquid is not only acquired and slowly distributed through a saturated region of the mixed material to more remote regions of the mixed material that have the ability to absorb liquids. Thus, the crosslinked absorbent mixed material provides initial liquid uptake speeds that are generally comparable or greater than conventional absorbent structures and have significantly increased liquid uptake rates for successive uptake of liquids relative to conventional mixed materials. The dry and wet structures of the crosslinked mixed material are illustrated in Figures 2A and 2B, which are seen in cross-sectional side view of a crosslinked absorbent composite material. Figure 2A is a cross-sectional view of the dry mixed material shown in Figure 1 indicating regions 12 and 14 and the relatively uniform thickness of the unmoistened mixed material. Fig. 2B is a cross-sectional view of the mixed material shown in Fig. 1 in a wet state, for example, after the discharge of the liquid and absorption of the liquid and swelling and expansion of the absorbent material. With reference to Figure 2B the enriched regions of absorbent material 12 (i.e., liquid storage regions) are shown as channels or gratings separated by fibrous regions 14 (i.e., liquid distribution zones) that form a valley floor or channel between the reticles. At least in part it is because the cross-linked structure of the moistened fibrous composite material, the subsequent discharges of liquid are rapidly absorbed by the crosslinked mixed material compared to mixed materials containing absorbent material in other configurations, for example, compounds in which The absorbent material is evenly distributed substantially through the mixed material and they are particularly susceptible to gel blocking, reduced uptake rates and fluid leakage. The rates and times of liquid capture for a representative cross-linked absorbent material are compared with those of the internal storage structures having relatively uniform distributions of absorbent material in the example. The rates of uptake for the cross-linked absorbent mixed material were significantly higher than for commercially available internal structures that showed that the uptake rates were substantially reduced with successive discharges. In contrast, the mixed material of the invention maintained high velocities in three discharges. The crosslinked mixed material also exhibited higher speeds compared to a mixed wet material of similar composition with a relatively uniform distribution of absorbent material throughout the mixed material. Example 2 compares the fibrous absorption characteristics of a representative cross-linked absorbent composite material with a commercially available diaper inner structure and an air-laid fibrous core containing superabsorbent material uniformly distributed substantially throughout the mixed material. Horizontal and vertical absorption indicates that the commercial air-laid core has the poorest absorption characteristics, while the cross-linked mixed material has strips of absorbent material showing significantly increased absorption compared to a mixed material similarly composed includes absorbent material evenly distributed in relative form. The distribution of liquid from the unloading site along the mixed material demonstrates the absorption capacity of the mixed material and the efficiency of the use of the material. The liquid distribution of a representative cross-linked mixed material is compared to two commercially available inner diaper cores or structures in example 3. The results indicate that in contrast to commercial cores that suffer from fluid accumulation at the discharge site, the material mixed reticulate has an almost ideal distribution, distributing the liquid throughout the mixed material using the components of the mixed material. As the liquid discharges are absorbed in a conventional storage core at a speed lower than the average urination speed of an infant, the liquid can leak from the diaper at its edges, to prevent such leakage, the diaper manufacturers have developed elaborate and costly leg cuffs that fit tightly around the infant's leg and are generally uncomfortable and leave marks. When incorporated into a diaper as an internal storage structure, the crosslinked composite material of this invention overcomes the problems of edge leakage associated with conventional internal storage structures. Accordingly, in a preferred embodiment, the crosslinked absorbent composite material includes outer bands of absorbent material that include relatively greater amounts of absorbent material than the inner bands. With reference to Figure 3, the enriched regions of outer absorbent material 12 have a greater amount of absorbent material compared to inner regions 12 and, as a consequence, have a greater absorbent capacity and therefore can swell and expand to a larger size. than those crosslinked containing a relatively smaller amount of absorbent material. The internal reticulated absorbent structure having a relatively greater amount of absorbent material in the outermost regions 12 can assist in the prevention of leakage of liquid from the edge of the mixed material. In another preferred embodiment, the enriched regions of outermost absorbent materials 12 contain absorbent material having a higher absorbent and / or liquid retention capacity than the absorbent material contained in inner regions 12. The skin of an infant is always susceptible to the irritation and itching that results from the moisture associated with the liquid retained from a diaper storage core. The amount of liquid released from an absorbent article that has acquired liquid refers to as "rewetting". Although a storage core surface is usually necessarily hydrophilic to effectively absorb the liquid, said hydrophilic surfaces also promote rewetting. In contrast to conventional absorbent articles that are in continuous contact with a user's skin, the surface of the crosslinked mixed material makes contact with the user only at the upper edges of the crosslinked material thereby minimizing contact with the skin. of the user, as well as reducing rewetting. Because the minimized contact between the skin of an infant and the wetted surface of the crosslinked absorbent composite compared to the wetted surface of a conventional storage core, the crosslinked absorbent mixed material offers the health-related benefits of the skin. and comfort for the user. It is contemplated that the cross-linked structure of the mixed material also provides skin health benefits related to cooling and air flow through an absorbent article containing the crosslinked mixed material. The rewet performance of a crosslinked absorbent mixed material is compared to a diaper core commercially available in Example 1. Generally, for successive discharges, rewetting increases in the commercial core. In contrast, the rewetting remains low and substantially unchanged in the crosslinked mixed material of this invention.

The structure of the crosslinked mixed material offers the possibility of an additional reduction in rewetting. The discharge of liquid generally occurs through the width of the mixed material including bands of fibrous regions and regions enriched with absorbent material. The liquid is generally acquired and rapidly distributed through the fibrous regions of the mixed material (i.e., regions 14) and generally stored in the regions of the mixed material enriched with absorbent material (i.e., regions 12). Finally, the acquired liquid resides in the bands of absorbent material in the reticulated structure. To further reduce rewetting, the crosslinked absorbent mixed material may include a hydrophobic barrier that matches the top surface of the crosslinked mixed material (i.e., coatings for the surface of the regions 12). Suitable hydrophobic barriers generally include latex and other hydrophobic films and coatings known in the art. Because the distribution zones between the coated lattices (i.e., regions 14) are physically removed from the user and because the user is protected from the lattices containing the absorbent material and which have acquired liquid by a hydrophobic barrier, said mixed reticulated coated material, provides an increase in the health of the skin through a reduction of moisture in the skin. Optionally, a hydrophobic barrier can also be attached to the surface facing outwards from the mixed absorbent material. Said structure allows a reduction in the thickness of the polyethylene moisture barrier (i.e., mpenetrable backing sheet) which is traditionally used in a diaper. The application of a hydrophobic barrier to the surface towards the exterior of the mixed material would reduce the total cost and the use of material in an absorbent article that incorporates the crosslinked absorbent mixed material. Illustrated in Figure 4A, a representative cross-linked absorbent composite material having a hydrophobic barrier that matches the bands of absorbent material of the mixed material and that has been fixed to the inner surface of the mixed material. With reference to Figure 4A, the mixed coated material 20 includes regions 12 and 14, as described above, and hydrophobic barriers 16 that substantially match and overlie the regions 12 enriched with absorbent material. A representative cross-linked absorbent composite material having a hydrophobic barrier fixed to the outward facing surface of a cross-linked absorbent mixed material is illustrated in Figure 4B. The fibers are a main component of the cross-linked absorbent mixed material. The fibers suitable for use in the present invention are known to those skilled in the art and include any fiber from which a mixed absorbent material can be formed. Suitable fibers include natural and synthetic fibers. The fiber combinations include combinations of synthetic and natural fibers and treated and untreated fibers, they can also be used appropriately in the mixed material. Generally, the fibers are present in the mixed material in an amount of from about 20 to about 90 weight percent, preferably from about 50 to about 70 weight percent, based on the total weight of the mixed material. In a preferred embodiment, the mixed material includes about 60 weight percent fibers. The mixed material of the invention includes elastic fibers. As used herein, the term "elastic fiber" refers to a fiber present in the mixed material that imparts crosslinking to the mixed material. Generally, elastic fibers provide the mixed material with volume and elasticity. The incorporation of elastic fibers in the mixed material allows the mixed material to expand when liquid absorption is present without loss of structural integrity. The elastic fibers also impart softness to the mixed material. further, the elastic fibers offer advantages in the process of forming the mixed material. Due to the porous and open structure that results from mixed wetted materials including elastic fibers, these mixed materials drain water relatively easily and therefore can be de-wetted and dried more easily than wet mixed materials that do not include elastic fibers. Preferably, the mixed material includes elastic fibers in an amount of from about 10 to about 60 weight percent, most preferably from about 20 to 50 weight percent, based on the total weight of the mixed material. The elastic fibers include synthetic and cellulosic fibers. Preferred elastic fibers include chemically hardened fibers, sinuous fibers, chemithermomechanical pulp (CTMP) and prehydrolyzed kraft pulp (PHKP). The term "chemically hardened fiber" refers to a fiber that has been hardened by chemical means to increase the stiffness of the fiber under dry and wet conditions. The fibers can be hardened by the addition of chemical curing agents that can coat and / or impregnate the fibers. Hardening agents include polymeric wet strength agents that include resinous agents such as, for example, polyamide-epichlorohydrin and polyacrylamide resins described below. The fibers can also be hardened by modifying the structure of the fiber, for example, by chemical entanglement. Preferably, the chemically hardened fibers are internally interwoven cellulosic fibers. The elastic fibers may include non-cellulosic fibers including, for example, synthetic fibers such as polyolefin, polyamide and polyester fibers. In a preferred embodiment, the elastic fibers include interwoven cellulosic fibers. As used herein, the term "sinuous fiber" refers to a cellulosic fiber that has been chemically treated. The sinuous fibers include, for example, fibers that have been treated with ammonia. In addition to the elastic fibers, the mixed material of the invention includes matrix fibers. As used herein, the term "matrix fiber" refers to a fiber that is capable of forming hydrogen bonds with other fibers. The fibers of the matrix are included in the mixed material to impart resistance thereto. The fibers of the matrix include cellulosic fibers such as wood pulp fibers, highly refined cellulosic fibers and high surface area fibers such as expanded cellulosic fibers. Other suitable cellulosic fibers include cotton lint, cotton fibers and hemp fibers, among others. Mixtures of fibers can also be used. Preferably, the mixed material includes matrix fibers in an amount of from about 10 to about 50 weight percent, more preferably from about 15 to about 30 weight percent, based on the total weight of the mixed material. The mixed material of the present invention preferably includes a combination of matrix and elastic fibers. In a preferred embodiment, the mixed material includes elastic fibers in an amount of about 25 to about 50 weight percent, and matrix fibers in an amount of about 10 to about 40 weight percent based on weight total of the mixed material. In a more preferred embodiment, the mixed material includes from about 30 to about 45 weight percent elastic fibers, preferably interlaced cellulosic fibers, and from about 15 to about 30 weight percent matrix fibers, preference wood pulp fibers, based on the total weight of the mixed material. For representative mixed materials formed by the processes of air deposition and foaming, the mixed material preferably includes about 45 weight percent elastic fibers (e.g., interlaced cellulosic fibers) and about 15 weight percent of matrix fibers. The cellulosic fibers are a basic component of the crosslinked absorbent mixed material. Although available from other sources, cellulosic fibers are derived mainly from wood pulp. Wood pulp fibers suitable for use with the invention can be obtained from well-known chemical processes, such as Kraft and sulfite processes, with or without subsequent bleaching. The wood pulp fibers can also be processed by thermomechanical or chemimetromechanical methods, or combinations thereof. The preferred pulp fiber is produced by chemical methods. Crushed wood fibers, recirculated or secondary wood pulp fibers and pulp fibers of bleached and unbleached wood can be used. Soft woods and hard woods can be used. The details of the selection of wood pulp fibers are well known to those skilled in the art. These fibers are commercially available from a number of companies, including the Weyerhaeuser Company, the agent of the present invention. For example, suitable cellulosic fibers produced from southern pine that can be used with the present invention are available from Weyerhaeuser Company under the designations CF416, NF405, PL416, FR516 and NB416. The wood pulp fibers of the present invention can also be pretreated before being used with the present invention. This pretreatment may include physical treatment, such as by subjecting the fibers to steam, or chemical treatment, for example, by interlacing the cellulose fibers using any of a variety of crosslinking agents. The entanglement increases the volume and elasticity of the fiber, and can thus improve the absorbency of the same. In general, the interlaced fibers are twisted or curled. The use of interlaced fibers allows the mixed material to be more elastic, softer, more bulky, have better absorbency and be easier to densify than a mixed material that does not include them. Suitable cross-linked cellulosic fibers produced from southern pine are available from Weyerhaeuser Company under the designation NHB416. Interlaced cellulosic fibers, and methods for their preparation, are described in the U.S. Patents. Nos. 5,437,418 and 5,225,047, issued to Graef et al., Expressly incorporated herein by reference. The interlaced fibers are prepared by treating cellulosic fibers with an entanglement agent. Suitable cellulose crosslinking agents include formaldehyde addition products based on aldehyde and urea. See, for example, the patents of E.U.A. Nos. 3,224,926; 3,241, 533; 3,932,209; 4,035,147; 3,756,913; 4,689,118; 4,822,453; patent of E.U.A. 3,440,135 issued to Chung; patent of E.U.A. 4,935,022 issued to Lash et al .; patent of E.U.A. 4,889,595 issued to Herrón et al .; patent of E.U.A. 3,819,470 issued to Shaw et al .; patent of E.U.A. 3,658,613 issued to Steijer et al .; and patent of E.U.A. 4,853,086 issued to Graef et al., All of which are hereby expressly incorporated herein by reference. The cellulosic fibers have also been entangled by carboxylic acid entanglement agents, including polyboxic acids. The patents of E.U.A. Nos. 5,137,537; 5,183,707; and 5,190,563, describe the use of C2-C9 polycarboxylic acids containing at least three carboxyl groups (eg, citric acid and oxydisuccinic acid) as crosslinking agents. Suitable urea-based entanglement agents include methylolated ureas, cyclic methylolated ureas, cyclic lower alkyl methylolated ureas, cyclic methylolated dihydroxy ureas, cyclic dihydroxy ureas and cyclic ureas substituted with lower alkyl. Preferred specific urea-based entanglement agents include dimethylol urea (DMU, bis [N-hydroxymethyl] urea), dimethylol-ethylene urea (DMEU 1,3-dihydroxymethyl-2-imidazolidinone), dimethylol-dihydroxyethylene urea (DMDHEU) , 1,3-dihydroxymethyl-4,5-dihydroxy-2-imidazolidinone), dimethyldihydroxy urea (DMDHU, 1,3-di methyl 1-4,5-dihydroxy-2-imidazolidinone), dihydroxy-ethylene urea (DHEU, , 5-dihydroxy-2-imidazolidinone), and dimethyl-dihydroxyethylene urea (DMeDHEU, 4,5-dihydroxy-1,3-dimethyl-2-imidazolidinone). Suitable polycarboxylic acid crosslinking agents include citric acid, tartaric acid, malic acid, succinic acid, glutaric acid, citraconic acid, itaconic acid, tartratomonosuccinic acid and maleic acid. Other crosslinking agents of polycarboxylic acids include polymeric polycarboxylic acids such as polyacrylic acid, polymethacrylic acid, polymaleic acid, polymethylvinyl ether comaleate copolymer, polyvinyl vinyl ether co-itatate copolymer, acrylic acid copolymers and maleic acid copolymer. The use of polymeric polycarboxylic acid crosslinking agents such as polyacrylic acid polymers, polymaleic acid polymers, acrylic acid copolymers and maleic acid copolymers, is described in the patent application of E.U.A. series No. 08 / 989,697, filed on December 12, 1997 and assigned to Weyerhaeuser Company. Mixtures of entanglement agents can also be used. The entanglement agent may include a catalyst to accelerate the binding reaction between the entanglement agent and the cellulosic fiber. Suitable catalysts include acid salts such as ammonium chloride, ammonium sulfate, aluminum chloride, magnesium chloride and alkali metal salts of acid containing phosphorus. Although not to be considered as a limitation, examples of pretreatment fibers include the application of surfactants and other liquids that modify the surface chemistry of the fibers. Other pretreatments include incorporation of antimicrobials, pigments, dyes, and softening or densifying agents. Fibers pre-treated with other chemicals, such as thermoplastic and thermosetting resins, can be used. Combinations of previous treatments can also be used. Similar treatments can also be applied after the formation of the mixed material in subsequent treatment procedures. The cellulose fibers treated with particle binders and / or densification / softness aids known in the art can also be used in accordance with the present invention. Particulate binders serve to adhere other materials, such as superabsorbent polymers of cellulose fibers, as well as other materials, to cellulosic fibers. The cellulosic fibers treated with suitable particle binders and / or densification / softness aids, and the processes for combining them with cellulose fibers, are described in the following US patents and patent applications: 1) Patent No. 5,543,215, entitled " Polymeric Binders for Binding Particles to Fibers "; 2) Patent No. 5,538,783, entitled "Non-Polymeric Organic Binders for Binding Particles to Fibers"; 3) Patent No. 5,300,192, entitled "Wet-laid Fiber Sheet Manufacturing With Reactivatable Binders for Binding Particles to Binders"; 4) Patent No. 5,352,480, entitled "Method for Binding Particles to Fibers Using Reactivatable Binders"; 5) Patent No. 5,308,896, entitled "Particle Binders for High-Bulk Fibers"; 6) Patent 5,589,256 entitled "Particle Binders that Enhance Fiber Densification"; 7) Patent No. 5,672,418 entitled "Particle Binders"; 8) Patent No. 5,607,759 entitled "Particle Binding to Fibers"; 9) Patent No. 5,693.41 1 entitled "Binders for Binding Water Soluble Particles to Fibers"; 10) Patent No. 5,547, 745, entitled "Particle Binders"; 1 1) Patent 5,641, 561, entitled "Particle Binding to Fibers" and 12) Patent No. 5,308,896, entitled "Particle Binders for High-Bulk Fibers"; 13) Patent 5,498,478 entitled "Polyethylene Glycol as a Binder Material for Fibers" 14) Patent 5,609,727 entitled "Fibers Product for Binding Particles" 15) Patent 5,571, 618 entitled "Reactivatable Binders for Binding Particles to Fibers" 16) Patent 5,447,977 entitled "Particle Binders for High Bulk Fibers "17) Patent No. 5,614,570 entitled" Absorbent Articles Containing Binder Carrying High Bulk Fibers "18) Patent No. 5,789,326 entitled" Binder Treated Fibers "; and 19) Patent No. 5,611, 885 entitled "Particle Binders"; all of them experience incorporated herein by reference. In addition to natural fibers, synthetic fibers including polymeric fibers such as polyolefin fibers, polyamide, polyester, polyvinyl alcohol and polyvinyl acetate can also be used in the absorbent mixed material. Suitable synthetic fibers include, for example, polyethylene terephthalate fibers, polyethylene, polypropylene, nylon and rayon. Other suitable synthetic fibers include those made of thermoplastic, cellulosic polymers and other fibers coated with thermoplastic polymers and multi-component fibers wherein at least one of the components includes a thermoplastic polymer. The single and multiple component fibers can be manufactured from polyester, polyethylene, polypropylene, and other conventional thermoplastic fibrous materials. Fibers of single and multiple components are commercially available. Suitable double component fibers include CeIbond fibers (available from Hoechst-Celanese Company) The mixed absorbent material can also include combinations of natural and synthetic fibers Synthetic fibers, including mixtures of natural and synthetic fibers can be used in the channels and / or distribution zones of the mixed material In a preferred embodiment, the mixed absorbent material includes a combination of pulp fibers (eg, from Weyerhaeuser, designation NB416) and interwoven cellulosic fibers (eg, from Weyerhaeuser, designation NHB416). preferred embodiment the mixed absorbent material includes a combination of wood pulp fibers present in the mixed material of about 50 weight percent and interlaced cellulosic fibers present in the mixed material in about 50 weight percent based on weight total of the fibers In a preferred embodiment the mixed material of deposition in h Wet or formed with foam is formed from a fiber supply that includes a mixture of southern fibers and interlaced fibers. The mixed materials formed from said mixture have a sheet integrity and an increased volume compared to mixed materials formed from a mixture of southern fibers and interlaced fibers that have been refined. Optionally the blend of southern fibers and refined interlaced fibers can also be slightly refined. The cross-linked absorbent mixed material can serve as a storage layer for liquids purchased when incorporated into an absorbent article. To effectively retain the liquids acquired, the mixed material includes absorbent material. As described above, the absorbent material is located in bands incorporated in the mixed fibrous material. Basically the bands of absorbent material can be configured in virtually any shape, size and location of the mixed material. Suitable configurations of the mixed material webs include any configuration that does not impede the uptake of liquid or promote gel blocking. The bands of the absorbent material may include straight and parallel bands, curved or wavy bands, and zigzag bands, among others. In Figure 5, a representative mixed band-absorbent material having wavy bands is illustrated. The bands of the mixed material may also include pulsed strips of absorbent material. As used herein, the term "pulsed band" refers to a band that extends along the length of the mixed material, which is not a continuous band but is a band that is interrupted by regions that substantially do not contain Absorbent material. One function of the pulsed webs is to provide the mixed material with an increased liquid distribution capacity across the width of the mixed material (i.e., the direction against the machine). A representative mixed band-absorbent material having pulsed webs is illustrated in Figure 6. As illustrated in Figure 6, in one embodiment, the pulsed webs have an ordered configuration of absorbent material to further increase the distribution of the liquid in the direction against the machine. Such an ordered configuration of absorbent material can be formed by injecting absorbent material into the mixed material through nozzles that deliver asynchronous pulses of absorbent material (i.e., pulses from a nozzle that is not synchronized with the pulses of another nozzle). The length of the pulsed web can vary extremely and for example it can be a point or small site of absorbent material with a length equal to approximately its width. A representative mixed band-absorbent material having pulsed webs having points or small sites is illustrated in Figure 7. The webs or webs of the mixed material are regions of the mixed material that are enriched with absorbent material. The distribution zones of the mixed material may include a certain amount of absorbent material. It will be appreciated that although the absorbent material is incorporated into the mixed web material, formation of strips of absorbent material in the mixed material can lead to the introduction of a certain amount of absorbent material into the fibrous distribution zones of said mixed material. The incorporation of absorbent material within the absorbent material can result in some mixing between the absorbent material and the fibers present in the fibrous base. The result is a transition zone between the mainly fibrous distribution zones and the bands of absorbent material. Said transition zone includes both fibers and absorbent material. The fibrous matrix of the mixed material can also be formed to include some absorbent materials and thereby result in distribution zones containing absorbent material. In embodiments having absorbent material in the distribution zones, the amount of absorbent material present is not so high as to reduce the effectiveness of these zones in distributing the purchased liquid.

Figures 8-10 show microphotographs of cross-sectional views of a representative mixed material formed by a wet deposition method. Figure 8 is a machine direction view of a cut in the counter-machine direction through the web of absorbent material of the mixed material (ie, the region 12 of the mixed material enriched with absorbent material). Figure 9 is a machine direction view of a cut in the machine direction through a distribution zone (i.e., the region 14 of the mixed material substantially free of absorbent material). Figure 10 is a view in the machine direction of a cut in the intermediate machine direction of a strip of absorbent material and a distribution zone (ie, through a transition zone as described above). As used herein, the term "absorbent material" refers to a material that absorbs liquid and that generally has a greater absorbent capacity than the cellulosic fiber component of the mixed material. Preferably, the absorbent material is a polymeric material generally water insoluble and expandable in water, capable of absorbing at least about 5, conveniently about 20, and preferably about 100 times or more its weight in saline solution (eg, solution saline at 0.9 percent). The absorbent material may be expandable in the dispersion medium used in the mixed material formation medium. In one embodiment, the absorbent material is untreated and is expandable in the dispersion medium. In another embodiment, the absorbent material is a coated absorbent material that is resistant to water absorption during the process of forming the mixed material. Such absorbent materials which are resistant to absorption include chemically modified absorbent materials or coated absorbent materials. The amount of absorbent material present in the mixed material can vary widely, depending on the desired use of the mixed material. When the absorbent blended material is used as a single absorbent mixed material as is, for example, an absorbent towel cloth, the amount of absorbent material in the mixed material is comparatively meshed (eg, about 0.1 weight percent). The amount of absorbent material present in an absorbent article such as an absorbent core of an infant's diaper is considerably greater. In said structure, the absorbent material is suitably present in the mixed material in an amount of from about 10 to about 80 weight percent, preferably from about 30 to about 50 weight percent, based on the total weight of the material mixed. In preferred embodiments, the mixed material includes about 40 weight percent absorbent material based on the total weight of the mixed material. The absorbent material can include natural materials such as agar, pectin and guar gum, and synthetic materials such as synthetic hydrogel polymers. Synthetic hydrogel polymers include, for example, carboxymethyl cellulose, alkali metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, copolymers of maleic anhydride-ethylene, polyvinyl ethers, hydroxypropyl cellulose, polyvinyl morpholinone, polymers and copolymers of vinylsulfonic acid, polyacrylates , polyacrylamides and polyvinyl pyridine, among others. In a preferred embodiment, the absorbent material is a superabsorbent material. As used herein a "superabsorbent material" refers to a polymeric material that is capable of absorbing large amounts of fluid by expanding and forming a hydrated gel (i.e., a hydrogel). In addition to absorbing large amounts of fluid, the superabsorbent polymers can also retain significant amounts of body fluids under moderate pressure. The superabsorbent polymers are generally grouped into three classes: starch graft copolymers, crosslinked carboxymethylcellulose derivatives and modified hydrophilic polyacrylates.

Examples of such absorbent polymers include hydrolyzed starch-acrylonitrile graft copolymers, neutralized starch-acrylic acid graft copolymers, saponified acrylic acid vinyl acetate ester copolymers, acrylamide copolymers or hydrolyzed acrylonitrile copolymers, modified crosslinked polyvinyl alcohol , neutralized self-crosslinked polyacrylic acids, crosslinked polyacrylate salts, carboxylated cellulose and neutralized crosslinked copolymers of maleic-isobutylene anhydride. The superabsorbent polymers are commercially available, for example, as is the case with polyacrylates from Clariant of Portsmouth, Virginia. These superabsorbent polymers exist in various sizes, morphologies and absorbent properties (available from Clariant under the trade designations IM 3500 and IM 3900). Other superabsorbent materials are marketed under the trade names SANWET (supplied by Sanyo Kasei Kogyo Kabushiki Kaisha) and SXM77 (supplied by Stockhausen of Greensboro, North Carolina). Other superabsorbent materials are described in the U.S.A. No. 4,160,059; U.S. Patent No. 4,676,784; U.S. Patent No. 4,673,402; U.S. Patent No. 5,002,814; U.S. Patent No. 5,057,166; U.S. Patent No. 4,102,340; and U.S. Patent No. 4,818,598, all expressly incorporated herein by reference. Products such as diapers incorporating superabsorbent materials are described in the U.S. patent. No. 3,669,103 and U.S. Patent No. 3,670,731. Suitable superabsorbent polymers useful in the mixed absorbent material of the present invention include superabsorbent particles and superabsorbent fibers. In a preferred embodiment, the mixed absorbent material of the present invention includes a superabsorbent material that expands relatively slowly for the purposes of manufacturing the mixed material and yet expands at an acceptable rate so as not to adversely affect the absorbent characteristics of the material. mixed or any structure that contains it. In one embodiment, the present invention provides a mixed material having absorbent material present in the mixed material in a concentration gradient. As used herein, the term "concentration gradient" refers to a gradient in the concentration of absorbent material in the fibrous composite material with respect to a particular dimension (ie, thickness, width and length) of the mixed material . A concentration gradient of absorbent material is formed through the selective distribution of the material within the mixed material. For example, as described below, the introduction of the absorbent material into the mixed material can be achieved by significant fiber mixing and a combined loss of a concentration gradient of absorbent material. Alternatively, the absorbent material can be introduced into the mixed material without significant fiber mixing resulting in the formation of a relatively higher concentration gradient. The concentration gradient of the mixed material can be present, either in the z-direction (ie, the thickness of the mixed material), the x-direction (ie, across the width of the mixed material, the direction versus the machine) , of the direction y (that is, along the length of the mixed material, of the address of the machine), or combinations of the directions x-, y-, and z-. The concentration gradients of absorbent material are contemplated to increase the absorption of liquid and in addition to reduce the gel blocking potential. In another embodiment, the present invention provides a mixed web material having absorbent material relatively uniformly distributed across its width and extending along its length beyond its thickness, in addition to the absorbent material present in the bands. The absorbent material is distributed within the mixed fibrous material as described below and preferably is present in the mixed material in a concentration gradient. Preferably the concentration gradient is present at least in the z-direction (ie, the thickness of the mixed material), although gradients in the x-y and y-directions are also contemplated to provide useful mixed materials. Mixed materials include those that have concentration gradients in one or more of the x-, y-, and z- directions. For embodiments having a z-direction gradient, the high concentration surface is preferably placed in an absorbent article outside the liquid discharge. In an embodiment having a concentration gradient in the x-direction (i.e., the width of the mixed material), the concentration is preferably maximally at the center of the width of the mixed material and is reduced outwardly from the center in the direction towards the edges of the mixed material. In another embodiment, the concentration is preferably maximum at the edges of the mixed material. The gradients in the direction and generally provide regions of absorbent material along the length of the mixed material. The mixed absorbent material of this invention may optionally include a wet strength agent. The wet strength agent provides increased resistance to the mixed absorbent material, and increases the wet integrity of the mixed materials. In addition to increasing the wet strength of the mixed materials, the wet strength agent can facilitate the attachment of the absorbent material, eg, superabsorbent material, to the fibrous matrix of the mixed material. Suitable wet strength agents include modified cationic starch having nitrogen containing groups (e.g., amino groups), such as those available from National Starch and Chemical Corp., Bridgewater, NJ; latex; wet strength resins such as polyamide-epichlorohydrin resin (e.g., Kymene (557LX, Hercules, Inc., Wilmington, DE), polyacrylamide resin (described, for example, in U.S. Patent No. 3,556,932, issued January 19, 1971 to Cocsia and others, also, for example, polyacrylamide commercially available and marketed by American Cyanamid Co., Stanford, CT, under the trade name of Parez (631 NC), urea-formaldehyde and melamine resins formaldehyde, and polyethyleneimine resins A general description of wet strength resins used in the field of paper and generally applicable in the present invention, can be found in TAPPI, series of monographs No. 29, "Wet Strength in Paper and Paperboard". ", Technical Association of the Pulp and Paper Industry (New York, 1965) In general, the wet strength agent is present in the composition in an amount of about 0.01 to about 2 percent by weight, preferably from about 0.1 to about 1 percent by weight, and more preferably from about 0.3 to about 0.7 percent by weight, based on the total weight of the mixed material. In a preferred embodiment, the wet strength agent useful in the formation of the mixed material of the present invention is a polyamide-epichlorohydrin resin, commercially available from Hercules, Inc. under the designation Kymene (The wet tensile strength. and dry of a mixed material formed in accordance with the present invention, will generally increase with increasing amount of wet strength agent It has been observed that after successive discharges of liquid, the mixed materials formed in accordance with the present The invention maintains its structural integrity and remains substantially intact by removal from a diaper structure, In contrast, conventional storage cores that contain superabsorbent materials lose their structural integrity in a wetted diaper. wetting of the cross-linked absorbent cores exceeds significant ectively that of conventional storage cores. The mixed absorbent material of the present invention generally has a basis weight of from about 50 to about 1000 g / m2, preferably from about 200 to about 800 g / m2. In a more preferred embodiment, the mixed absorbent material has a basis weight of from about 300 to about 600 g / m2. The basis weight of the mixed crosslinked material can vary and will depend on the intention of its use. When the intention to use the crosslinked mixed material is as a storage layer, the mixed material preferably has a basis weight greater than about 300 g / m.2. For use as a liquid handling layer, the mixed material preferably has a basis weight of about 100 g / m2 to about 400 g / m2. The mixed absorbent material generally has an average density (in the direction against the machine) of about 0.03 to about 0.8 g / cm3, preferably about 0.04 to about 0.3 g / cm3. In a more preferred embodiment, the mixed absorbent material has an average density of about 0.15 g / cm3. In one embodiment, the mixed absorbent material is a densified mixed material. The densification methods useful for producing the densified mixed materials of the present invention are well known to those skilled in the art. See, for example, the patent of E.U.A. No. 5,547,541 and serial patent application No. 08 / 859,743, filed May 21, 1997, entitled "Softened Fibers and Methods of Softening Fibers", assigned to Weyerhaeuser Company, both expressly incorporated herein by reference. The mixed densified cross-linked absorbent storage materials after drying of this invention, generally have a density of about 0.1 to about 0.5 g / cm3, and preferably 0.15 g / cm3. Densification can also be used before drying. Preferably, the mixed absorbent material is densified by a method of heated calender rolls or at room temperature. See, for example, the patents of E.U.A. Nos. 5,252,275 and 5,324,575, both expressly incorporated herein by reference. The composition of the crosslinked absorbent composite material of the present invention can be varied to meet the needs of the desired end product in which it can be incorporated. In a preferred embodiment, the absorbent blended material of the present invention includes about 60 weight percent cellulosic fibers about 40 weight percent absorbent material (e.g., superabsorbent particles) and about 0.25 weight percent resistance agent. Wetted (for example, polyamide-epichlorohydrin resin, Kymene (, approximately 4.54 kg of resin per ton of fiber), based on the total weight of the mixed material The dimensions of the cross-linked absorbent composite material can be varied considerably depending on the the desired characteristics of the mixed material and the intention of its use Typically, for a child's diaper, the mixed material includes from about 2 to about 6 bands of absorbent material across the width of the mixed material, the edges at The outside of the mixed material preferably includes bands of absorbent material, for a typical product of incontinence. In the adult, the mixed material may include 10 or more bands. Although the configuration and width are not a particularly critical point, the bands of absorbent material are usually spaced regularly across the width of the mixed material and have widths of about 0.254 cm to about 1.90. The bands are typically separated in distribution zones with widths of about 0.254 cm to about 2.54 cm. The feminine hygiene products containing a relatively low amount of absorbent material and cross-linked mixed materials useful in such products have relatively narrow bands of absorbent material. The crosslinked structure of the mixed material of the present invention can be formed with a variety of methods known to those skilled in the art, all considered within the scope of that invention. For example, a crosslinked structure can be formed by linking one or more bands of absorbent material or collection / distribution material to a fibrous base.; depositing, injecting, applying, impregnating, or infusing absorbent material into a fibrous base; or by wet deposition and foaming processes as described below. For embodiments in which the latter are formed by linking strips of absorbent or pick-up / distribution materials to a fibrous base, the webs may also include other materials such as fibers. For these embodiments, the bands containing absorbent material and the fibrous base can be formed independently by methods known to those skilled in the art, including methods of air deposition, wet deposition, and foaming, as described below. The crosslinked mixed material can be formed by fixing or bonding the bands to a fibrous base by any method that allows fluid communication between these components of the mixed material. Suitable means for securing or binding them include, for example, gluing, heat setting and entanglement. Generally, these embodiments have improved the absorbent properties that are due to the communication of increased fluids between the components of the mixed material compared to the mixed materials having absorbent material in simple proximity with the fibrous component of the mixed material. With reference to FIG. 1 1A, the cross-linked absorbent composite material 22 includes distribution zones 26 which serve to rapidly acquire and distribute the liquid to the storage areas 24 and the storage core 28. As indicated above, the distribution zones 26 they are composed mainly of fibrous materials, and the storage zones 24 and the core 28 are generally fibrous layers that include absorbent material. As described above, the mixed material 22 can be formed by bonding strips of fibrous materials and absorbent materials to a storage core to form the distribution zones 26 and the storage zones 24, respectively. Alternatively, the storage areas 24 can be formed integrally with the storage core 28 and similarly, the distribution zones 26 can also be integrally formed with storage areas 24 and the core 28. Although the distribution zones are generally prepared From mixed materials deposited in the air, the absorbent material containing the storage areas can be made from mixed materials with air deposition. In a preferred embodiment, the distribution zones are formed with a mixed fibrous wet deposition material including fibrous materials suitable for the collection and distribution of the liquid, and the zones and the storage core are formed with mixed fibrous materials with air deposition which includes absorbent material suitable for the storage of liquids. In another preferred embodiment, the zones and the storage core are formed with a mixed wet deposition material. Generally, a mixed absorbent material having such a structure has increased liquid uptake compared to conventional storage cores and those that have relatively poor fluid communication between the components of the mixed material. The multi-layer absorbent structures may also include the cross-linked absorbent mixed material. Said structure is illustrated in Figure 11 B. With reference to Figure 1 1 B the absorbent structure 23 includes a fibrous composite material 22 and a capture layer 32 (for example, formed mainly from fibrous materials). As indicated above, the mixed material 22 includes distribution zones 26, storage zones 24 and storage core 28. Cross-linked mixed materials having a unitary structure are generally preferred due to the close communication of fluids between the components (i.e., regions of mixed material) and for reasons related to manufacturing capacity. Accordingly, in a preferred embodiment, the crosslinked absorbent mixed material is an integrally formed unitary structure. The cross-linked absorbent mixed material can be formed by wet deposition and foaming processes. These general methodologies are known to those skilled in the wood pulp processing art. Preferably, the cross-linked absorbent mixed material is prepared by means of wet deposition or foaming processes. A representative example of a wet deposition process is described in the US patent. No. 5,300,192, issued April 5, 1994, entitled "Wet-laid Fiber Sheet Manufacturing with Reactivatable Binders for Binding Particles to Fibers", expressly incorporated herein by reference. Wet deposition processes are also described in standard texts, such as Casey, Pulp and Paper, 2a. edition, 1960, volume II, chapter VIII - Sheet Formation. Representative foaming procedures useful in forming the mixed material of the present invention are known in the art, and include those described in the U.S. Patents. Nos. 3,716,449; 3,839,142; 3,871, 952; 3,937,273; 3,938,782; 3,947,315; 4,166,090; 4,257,754; and 5,215,627, assigned to Wiggins Teape and related to the formation of fibrous materials from foamed aqueous fiber suspensions, and "The Use of an Aqueous Foam as a Fiber-Suspending Medium in Quality Papermaking", Foams, memoirs of an organized symposium by the Chemical Industry Society, Colloid and Surface Chemistry Group, RJ Akers, Ed., Academic Press, 1976, which describes the Radfoam procedure, all expressly incorporated herein by reference. The absorbent material is incorporated in the mixed material during the formation thereof. In general, the method of forming the crosslinked absorbent mixed material includes depositing the absorbent material in a fibrous web, and then drying the mesh, if necessary, to provide the mixed material of the invention. In a wet deposition method, the absorbent material is preferably applied within a fibrous suspension that has been deposited on a foraminous support (i.e., a forming wire). In the method, the absorbent material is injected into at least one partially dehumidified fibrous mesh formed by depositing a fibrous suspension on a forming wire. The fibrous suspension preferably includes fibers and a wet strength agent in a dispersion medium (eg, a primarily aqueous medium such as water). The absorbent material can be introduced into the fibrous web such as a dry particle or, preferably, as a liquid suspension in an aqueous medium, preferably cold water (eg -1.1 ° C and 7.2 ° C) The absorbent material it is generally injected into the fibrous mesh partially dehumidified immediately after the deposition of the suspension in the forming wire. The absorbent material is preferably deposited in the partially dehydrated fibrous mesh (ie, before the dehumidification of the mesh ends and during the formation of the wet mixed material where the consistency of the mesh increases with respect to the suspension and, in any case , prior to the drying stage). After depositing the absorbent material in the partially dehumidified fibrous web, the mesh containing the fibers and the absorbent material is subjected to the further removal of at least a portion of the dispersion medium and water, preferably by vacuum, to provide a mixed material. damp. Subsequently, the wet mixed material is dried to provide the mixed absorbent material. It is desirable to inhibit the absorption of liquid by the absorbent material during the mesh forming process. To inhibit the absorption of liquid, at least the partially dehumidified mesh may be added as an aqueous suspension in cold water at a temperature in the range of about 0-5 ° C, preferably around 0-3 ° C. , and most preferably around 1 ° C. Alternatively, the absorbent material can be cooled below 0 ° C, by placing or storage in a conventional freezer, and then forming a suspension in water, preferably in cold water, immediately prior to mesh formation. Limiting the period in which the absorbent material is in contact with the liquid during the forming process also has a positive effect by limiting the absorption of liquid from the absorbent material. Preferably, the suspension of the absorbent material is added to the mesh in which the water has been removed at least partially within about 10 seconds, and more preferably within about 5 seconds after preparing the suspension. By limiting the absorption of liquid by the absorbent material during the formation process, the energy and / or drying time of the mesh, and the consequent associated expense, can be greatly reduced. This advantage can result in mesh forming processes that are more cost effective and can represent significant savings for consumer absorbent products such as diapers., feminine care products and incontinence products in adults. As described above, the absorbent blended material of the present invention includes strips of absorbent material which are laterally spaced across the width of the mixed material and which extend longitudinally along the length of the mixed material in the machine direction . A strip configuration can be achieved as such by various methods including injecting the absorbent material into the fibrous web, to which the water has been at least partially removed, by means of openings or nozzles separated laterally across the width of the web. mesh. The nozzles are connected to a supply of absorbent material. The nozzles can be placed in various configurations and have holes of varying size to provide bands having various configurations including, for example, various widths. The absorbent material is preferably deposited as a suspension in cold water. For aqueous suspensions, the absorbent material is injected as a stream or stream into the fibrous mesh to which the water has been partially removed. The injection of the stream can result in significant mixing of the absorbent material and the fibers of the mesh. The degree of mixing can be controlled by several factors including among others the flow velocity, the mesh speed, the injection angle and the injection position in relation to the deposition of the fibrous suspension on the support, among others. In general, the closer the injection of absorbent material is to the point at which the removal of water from the fibrous mesh begins, the greater will be the mixing of absorbent material and fibers. In addition, the greater the mixing of absorbent material and fibers, the lower the concentration gradient of absorbent material resulting in the mixed material. Because the bands of absorbent material can be formed in the mixed material by deposition or injection through individual nozzles, the nature and characteristics of the channels that are ultimately formed in the mixed material can be controlled. For example, referring to the mixed material illustrated in FIGURE 3, the outermost channels contain absorbent material in relatively greater amounts compared to the inner channels. A mixed material can be formed as such by depositing larger concentrations of absorbent material, depositing absorbent material at a higher speed, or using nozzles having holes with larger diameter for the outermost positions. As indicated above, absorbent materials having different absorption and retention capacities can be selectively deposited in the bands. The deposition of individual bands also allows the formation of bands which may include materials in addition to the absorbent material. For example, additional fibers can also be introduced into the deposited suspension using said nozzles. Accordingly, channels having additional fibers, including fibers different from those of the deposited fibrous suspension, can be incorporated into the mixed material. In a preferred embodiment, the mixed absorbent material includes strips of absorbent material that also include additional fibers such as, for example, hardwood fibers and / or synthetic fibers. The use of different fibers can be used to form channels having, for example, relatively higher base weights; greater volume and smoothness; increased absorption and increased rewet performance. In this way, the channels of the mixed material can be formed from completely different components compared to the mixed base material (ie, the fibrous suspension initially deposited). The regions of the absorbent material enriched with absorbent material can be stabilized to increase the structural integrity of the band or channel. The integrity of the channel can be increased by depositing, in addition to the absorbent material, a wet strength agent (e.g. Kymene®) and / or fibrous materials including, for example, microfibrillated cellulose and superabsorbent fibrous materials. The superabsorbent fibrous materials are described, for example, in the patent E.U.A. No. 5,607,550 specifically incorporated in the present invention for reference. The advantage of versatility allows the design and formation of various mixed corrugated absorbent materials. For example, the mixed base material can be designed to give strength and absorption, while the deposited bands can be designed to maximize expansion and absorbent capacity and to minimize rewetting. More specifically, for a mixed material that maximizes absorbent capacity, strength, and total material utilization, the mixed base material may include a blend of southern pine fibers, eucalyptus fibers, crosslinked fibers, and annealed agent. wet strength, and the webs may include a mixture of absorbent material and crosslinked cellulose fibers or fibers. For a mixed material having increased capacity and increased absorption for the absorbent material, the mixed base material may include a mixture of southern pine fibers, eucalyptus fibers and wet strength agent, and the webs may include a mixture of material absorbent, cross-linked cellulose fibers and microfibrillated cellulose. Another preferred absorbent blended material includes a mixed base material consisting of a refined blend of crosslinked cellulose fibers and eucalyptus fibers, and includes webs consisting of a mixture of absorbent material and unrefined crosslinked fibers. To reduce rewetting, synthetic fibers (eg PET fibers) can be introduced into the mixed material by depositing these fibers in the bands with absorbent material or by including part of the absorbent material in the distribution zones of the mixed material. The versatility of the method of the present invention allows the creation of corrugated absorbent mixed materials having a variety of compositions and absorbent properties. The method of the present invention also allows the deposition of foam dispersions as webs of materials in a fibrous suspension. In one embodiment, the mixed material has a fibrous base deposited in wet and bands formed with foam. In another embodiment, the mixed material includes a fibrous base formed with foam and bands deposited wet and, even in another embodiment, the mixed material includes a fibrous base formed with foam and webs. The ability to deposit a foam dispersion allows the use of a wide variety of fiber types, lengths and deniers in the absorbent webs of the mixed material. By selecting the fibers, the bands (and finally the channels of the mixed material) can be, for example, soft and can have a degree of stretch. By forming a mixed material having stretching capabilities, a center configured from a rectangular mixed material can be formed, thereby eliminating the need to configure the center by cutting, which results in waste of material. Such a center has the highest density of absorbent material in the crotch area, the liquid discharge site. As stated above, the mixed absorbent material of the present invention can be formed from a combination of fibers and, optionally, wet strength agent, dispersion medium, and absorbent material. In one embodiment, a fibrous suspension is formed by combining fibers directly and, optionally, wet strength agent, in a dispersion medium followed by the addition of absorbent material, preferably as a liquid suspension in cold water, to a screen. fibrous to which the water has been removed at least partially, on a foraminous support. In another embodiment, the absorbent material is added to the fibrous web in which the water has been partially removed on a foraminous support in combination with the fibers as a suspension containing fibers and absorbent material. Such a suspension can be prepared by first combining the fibers with a dispersion medium to which the absorbent material is then added in a second step. Once the fibrous suspension has been deposited on the foraminous support, the dispersion medium begins to drain from the deposited suspension to provide a fibrous mesh to which the water has been at least partially removed. Removal of the dispersion medium (eg, water) from the deposited fibrous suspension (i.e., the mesh to which the water has been partially removed) continues by, for example, the application of pressure, vacuum and combinations of the same, and results in the formation of a wet mixed material. The mixed absorbent material of the present invention is finally produced by drying the wet mixed material. The drying removes at least a portion of the remaining dispersion medium and water and provides a mixed absorbent material having the desired moisture content. Appropriate methods of drying the mixed material include, for example, the use of drying cans, air floats and dryers with air circulation. Other methods and drying apparatuses known in the pulp and paper industry can also be used. . Temperatures, pressures and drying times are typical for the equipment and methods used, and are known to those skilled in the art in the pulp and paper industry. For methods with foam, the fibrous suspension is an aqueous or foam suspension that also includes a surfactant. Suitable surfactants include ionic, non-ionic, and amphoteric surfactants known in the art. The deposition of the components of the absorbent mixed material on the foraminous support finally results in the formation of a wet mixed material that includes absorbent material that could have water absorbed, and as a result, could have an expanded size. The water is extracted from the mixed wet material containing the absorbent material distributed on the support and the wet mixed material is dried.

In the methods of the present invention, the absorbent material preferably absorbs less than about 20 times its weight in the dispersion medium, more preferred less than about 10 times, and even more preferred less than about 5 times its weight in the medium of dispersion. Other preferred absorbent materials include materials that absorb liquid only by prolonged contact with the liquid, or that absorb liquid only under certain conditions, and that do not absorb any significant amount of liquid during the forming process. Foam methods are advantageous for forming the mixed absorbent material of the present invention for several reasons. In general, foamed methods provide fibrous meshes having both relatively low density and relatively high tensile strength. For meshes constituted substantially by the same components, the meshes formed with foam generally have higher densities than the meshes deposited in the air and smaller than the meshes deposited in wet. Likewise, the tensile strength of the meshes formed with foam is substantially greater than those of the meshes deposited in the air and close to the resistance of the meshes deposited in wet. In addition, the use of foam forming technology allows for better control of the orientation and uniform distribution of the fibers and allows the incorporation of a wide variety of materials (for example, long and synthetic fibers that can not be easily incorporated into the wet deposition procedures) in the mixed material. One machine for implementing the method of the present invention is a conventional papermaking machine (wet-laid pulp machine) that has been modified to include a plurality of nozzles placed downstream from the outlet of the headbox. In general, the nozzles are laterally spaced at intervals, for example, at regular intervals, across the width of the mesh. As described above, the nozzles are connected to a supply of absorbent material and, in a preferred embodiment, an aqueous suspension of cooled absorbent material is pumped into the nozzles to form an aqueous stream or jet which strikes and penetrates the surface of the absorber. deposited fibrous suspension (ie the fibrous mesh to which the water has been partially removed) as the wet mixed material is formed. Because the wet mixed material moves away from the headbox as it is formed, the bands of absorbent material are created in the mixed material along the machine direction. By using vacuum, the machine drains the water from the mixed material. The wet mixed material is then dried to provide the final product. FIG. 12A shows a diagrammatic view of a representative machine and the method for forming the corrugated absorbent composite material of the present invention. Referring to FIGURE 12A, the machine 100 includes the foraminous support 102 (ie a wire for forming); the vacuum heads 104 that remove water from the fibrous suspension 124 to provide the wet mixed material 120; the head box 106 for depositing the fibrous suspension on the support 102; the manifold 108 for the nozzle that injects the absorbent material 122, preferably as an aqueous suspension, into the mesh 126 to which the water has been partially removed; the fibrous suspension supply 112; the supply of absorbent material 114; the pumps 1 10 for supplying the fibrous suspension and the absorbent material from their respective supplies to the head case 106 and the manifold 108, respectively; and the drying means 1 16. Briefly, the fibrous suspension 124 is deposited from the head box 106 on the support 102 and the water is removed to provide the mesh 126 to which the water has been partially removed. The absorbent material 122, preferably as an aqueous suspension, is injected through the manifold 108 of the nozzle into the mesh 126 to which the water has been partially removed, preferably before the water is removed intensively in the vacuum heads 104. As described above, the manifold 108 includes a plurality of nozzles positioned across the width of the support 102 (i.e. in the transverse direction of the machine) to supply and inject the absorbent material in strips across the width of the mixed material. The water in the wet mixed material 120 is further removed along the support 102 and then dried by means of the drying means 116 (for example, heated cans, drying oven, dryer with air circulation). FIG. 12B illustrates a top plan view of the injection of absorbent material into the aqueous suspension. The absorbent composite material of the invention can be formed by devices and methods that include a twin wire configuration (ie, twin forming wires). FIGURE 13 shows a machine with twin wires to form the mixed materials of the invention. Referring to FIGURE 13, the machine 200 includes the twin forming wires 202 and 204 in which the components of the mixed material are deposited. Basically, the fibrous suspension 124 is inserted into the head box 212 and is deposited on the forming wires 202 and 204 at the outlet of the headbox. The vacuum elements 206 and 208 remove water from the fibrous suspensions deposited on the wires 202 and 204, respectively, to provide meshes to which the partially water leaving the twin wire portion of the machine as the 126 mesh to which the water has been partially removed. The mesh 126 continues its journey along the wire 202 and the water is still removed therefrom by the additional vacuum elements 210 to provide the wet mixed material 120 which is then dried using the drying means 216 to provide the material mixed 10. The absorbent material can be introduced into the fibrous mesh in any of the positions in the twin-wire process depending on the desired configuration of the product. For example, the absorbent material may be introduced after the partially stripped fibrous web has left the portion of the twin wires of the machine and has traveled through the wire 202. Referring to FIG. FIGURE 13, the absorbent material 122 can be injected onto the mesh 126 to which the water has been partially removed in position 1. Alternatively, the absorbent material can be introduced into the mesh to which the water has been removed. water partially before the mesh leaves the twin wire portion of the machine (ie, in the headbox). Referring to FIGURE 13, the absorbent material 122 can be injected into the mesh in which the water has been partially removed in positions 2, 3, or 4, or in other positions along the wires 202 and 204 in which water has been removed from the mesh at least partially. The absorbent material can be introduced into the mesh to which the partially formed water that has traveled through the wire 202 and / or 204 has been removed. As indicated above, to form the mixed material of the invention for having strips of absorbent material extending in the machine direction of the mixed material, the absorbent material is injected into the fibrous meshes to which the water has been partially removed by the nozzles separated laterally across the width of the mesh . The nozzles are connected to a supply of absorbent material. The nozzles can be placed in different positions (for example, positions 1, 2, or 3 in FIGURE 13) as described above. For example, referring to FIGURE 13, the nozzles may be located in positions 2 for injecting absorbent material into the meshes to which the water has been partially removed over the wires 202 and 204. In general, the degree of mixing of the fibers with the absorbent material decreases as water is removed from the fibrous mesh (eg less mixed in position 1 than in position 2, and less mixed in position 2 than in position 3). Depending on the position in which the absorbent material is introduced, the twin wire method for forming the mixed material of the present invention can provide a mixed material having a fibrous stratum. Representative mixed materials of the invention having fibrous strata formed by the twin wire method of the present invention are shown in FIGS. 14A-H. Referring to FIGURE 14A, representative mixed materials 10 include regions 12 enriched with absorbent material, distribution zones 14 substantially free of absorbent material, and fibrous strata 1 1 which extend together with the outer surfaces of the mixed material. 10. Referring to FIGURE 14 A, the mixed material 10 can be formed by a method that introduces the absorbent material into an individual mesh that has been partially removed from the water (ie, a mesh that travels over the wire 202 or 204). FIGURES 14B and 14C show mixed materials formed in a similar manner that have the absorbent material extending into the mixed material towards relatively greater depths (ie, penetration in the z-direction). Referring to FIGURE 14 D, the mixed material 10 includes the absorbent material introduced into the fibrous center. Such a mixed material can be formed by adjusting the penetration depth of the absorbent material by, for example, the distance of the nozzle from the forming wire or the angle of injection of the absorbent material. Alternatively, the mixed material of the invention can be formed by a twin wires method that introduces the absorbent material in both meshes to which the water has been partially removed (i.e., the meshes traveling on the wires 202 and 204). Such method includes two sets of nozzles, a first set of nozzles for injection in a mesh to which the water has been partially removed, and a second set of nozzles for injection in the other mesh to which the water has been removed partially. Referring to FIGURE 14 E, the mixed material includes regions enriched with absorbent material that extend substantially through the depth of the mixed material (ie, z-direction). Such a mixed material configuration can be formed from a pair of nozzle assemblies whether they are positioned or synchronized to provide strips of absorbent material that are aligned in the z-direction. By displacing one of the nozzle assemblies of the other, or by providing pulses of unsynchronized absorbent material from a pair of aligned nozzle assemblies, mixed materials are provided which have strips of displaced absorbent material.

Such a configuration of mixed material is illustrated in FIGURE 14 F. FIGURES 14 G and 14 H illustrate mixed materials formed by methods similar to those provided by the mixed materials shown in FIGURES 14 E and 14 F, respectively, but in FIGS. In contrast to those mixed materials, the mixed materials of FIGURES 14G and 14H are formed by introducing absorbent material to a depth of penetration less than that of the mixed materials in FIGURES 14 E and 14 F. As shown in FIGURE 14, the mixed material of the present invention can include integrated phases having fibrous layers coextensive with the outer surfaces of the mixed material. These mixed materials can be formed from multi-layer inclined forming devices or with twin wire forming devices with sectioned head boxes. These methods can provide mixed materials stratified or with phases having strata or phases with specifically designed properties and containing components to obtain mixed materials having the desired properties. The regions of the mixed material of enriched absorbent material (ie, the absorbent strips of the mixed material) can be located across the entire z direction by adjusting the base weights of the upper and lower layers. Basically, the position of the band of absorbent material in the z-direction of the mixed material effectively defines the fibrous stratum covering the band. For a forming method that includes a single portion of fiber, the position of the web can be adjusted by placing the injection system of absorbent material (e.g., set of nozzles) relative to the forming wire. For methods that include multiple portions, the upper and lower layers may be constituted by the same or different components and be introduced into a sectioned head box. Referring to FIGS. 13 and 14 A, the mixed material 10 having the layers 1 1 can be formed by the machine 200. For the mixed materials in which the layers 1 1 comprise the same components, a single portion of the same is introduced. fiber 124 in the head box 212. To form mixed materials having layers 1 1 comprising different components, the head box 212 includes one or more baffles 214 for introducing the fiber portions (e.g. 124a, 124b and 124c) that They have different compositions. In such a method, the upper and lower layers can be formed to include different components and have different base weights and properties. Preferably, the fluted mixed material is formed by a foam forming method using the components described above. In the foam forming method, fibrous meshes having multiple layers and including strips of absorbent material can be formed from multiple fibrous suspensions. In a preferred embodiment, the foam forming method is carried out on a twin wire former.

The method can provide a variety of mixed materials with multiple strata, including for example, mixed materials having three strata. A representative mixed material having three strata includes a first stratum formed from fibers (eg, synthetic fibers, cellulosic materials, and / or binding fibers); an intermediate layer formed from fibers and / or other absorbent material such as a superabsorbent material; and a third stratum formed from fibers. The method of the invention is versatile in the sense that such a mixed material can have relatively distinct and individual strata or, alternatively, it can have gradual transition zones from one stratum to the other. A representative method for forming a fibrous mesh having an intermediate layer generally includes the following steps: (a) forming a first fibrous suspension of foam comprising fibers and a surfactant in an aqueous dispersion medium; (b) forming a second fibrous suspension of foam comprising fibers and a surfactant in an aqueous dispersion medium; (c) moving a first foraminous element (e.g., a forming wire) in a first path; (d) moving a second foraminous element in a second path; (e) passing the first foam suspension in contact with the first foraminous element moving in a first path; (f) passing the second foam suspension in contact with the second foraminous element moving in the second path; (g) passing a third material between the first and the second foam suspension in such a way that the third material does not come into contact with any of the first or second foraminous element; and (h) forming a fibrous web from the first and second suspensions and from the third material by extracting the foam and liquid from the suspensions through the first and second foraminous elements. As indicated above, the method is suitably carried out in a twin wire forming device, preferably a vertical forming device, and more preferably, a vertical twin wire forming device with downward flow. In the vertical forming device, the trajectories for the foraminous elements are substantially vertical. FIGURE 15 illustrates a vertical twin wire forming device with representative downward flow useful for practicing the method of the invention. Referring to FIGURE 15, the forming device includes a vertical head box assembly having a forming device with a closed first (upper) end, closed first and second sides and an inner volume. A second (lower) end of the forming device is defined by moving the first and second foraminous members, 202, 204, and the forming protrusion 213. The inner volume, defined by the first closed end, the first and second sides and the first and second and second foraminous elements of the forming device, includes an interior structure 230 extending from the first end and towards the second end of the forming device. The inner structure defines a first volume 232 on one of the sides thereof and a second volume 234 on the other side thereof. The forming device further includes supply means 242 and means 243 for introducing a first fiber / foam suspension in the first volume, supply means 244 and means 245 for introducing a second fiber / foam suspension in the second volume. , and supply means 246 and means 247 for introducing a third material into the interior structure. The means for extracting foam (eg, suction boxes 206 and 208) from the first and second suspensions through the foraminous elements to form a mesh is also included in the assembly of the head box. In the method, the twin wire forming device includes means for introducing at least one third material through the inner structure such that the third material forms strips in the resulting mesh. Preferably, the introduction means include at least a plurality of conduits having a first effective length. A second plurality of conduits having a second effective length different from the first length can also be used. You can also use more than two sets of ducts. FIG. 16 illustrates another vertical twin wire forming device with representative downward flow useful for practicing the method of the invention. Referring to FIGURE 16, the forming device includes a vertical head box assembly having an interior volume defined by the first closed end, first and second closed sides and the first and second foraminous elements, 202 and 204, and includes an interior structure 230 extending from the first end and towards the second end of the forming device. In this embodiment, the structure 230 includes the plurality of conduits 235 and 236, and the optional divider walls 214. The interior structure defines a first volume 232 on one of the sides thereof and a second volume 234 on the other side of the same The forming device includes supply means 242 and means 243 for introducing a first fiber / foam suspension in the first volume, supply means 244 and means 245 for introducing a second fiber / foam suspension in the second volume, supply means 246 and means 247 for introducing a third material into the plurality of conduits 236, and supply means 248 and means 249 for introducing a third material into the plurality of conduits 235, and supply means 250 and the means 251 for introducing another material, such as a foam suspension, into the volume defined by the walls 214. The plurality of conduits 235 may have an effective length different from that of the plurality of conduits 236. The third material may be introduced. through conduits 235 and 236, or, alternatively, a third matepal may be introduced through conduits 235 and a fourth material may be introduced through ducts 236. Preferably, the ends of ducts 235 and 236 terminate at a position beyond where the suction boxes begin to extract foam from the suspensions in contact with the foraminous elements (i.e., beyond from the point at which the formation of the mesh begins). The plurality of conduits 235 and / or 236 is suitable for introducing strips or bands of a third material into the fibrous meshes formed in accordance with the present invention. It can be moved to the plurality of conduits 235 and 236 in a first dimension towards and away from the protrusion 213, and furthermore in a second dimension substantially perpendicular to the first, close to one or the other of the forming wires. In FIGURE 17 the representative plurality of conduits 235 and 236 is illustrated. Generally, the interior structure of the forming device (ie, structure 230 in FIGS. 15 and 16) is positioned with respect to the foraminous elements of such a structure. so that the material introduced through the inner structure does not enter directly into contact with the first and second foraminous elements. Accordingly, the material is introduced through the interior structure between the first and second suspensions after the suspensions have come in contact with the foraminous elements and the foam and liquid extraction of those suspensions has begun. A configuration as such is advantageous for introducing superabsorbent materials and for forming layered structures in which the third material is a foam / fiber suspension. Depending on the nature of the mixed material to be formed, the first and second foam / fiber suspensions may be the same, or different, one from the other and from the third material. In a preferred embodiment, the method includes introducing the third material into a plurality of different points to provide a mixed material having strips or strips of the third material within the product. The positions of at least a portion of the plurality of different points for introducing the third material into the headbox can be adjusted when desired to adjust the insertion point in a first dimension towards and away from the outlet of the box. head (i.e., the protrusion 213 in FIGURES 15 and 16); and to adjust at least a part of the plurality of points in a second dimension substantially perpendicular to the first dimension, close to one or the other of the forming wires. The method may also include using a plurality of different conduits, the conduits being at least two different lengths, for introducing the third material into the headbox. The method can also be used in head boxes that have dividing walls that extend a part of the length of the ducts towards the outlet of the headbox. Such head boxes are illustrated in FIGURES 13 and 16. Means for introducing the first and second foam suspensions in the first and second volumes may include any of the conventional types of ducts, nozzles, orifices, loaders, or the like. Typically, these means include a plurality of conduits that are provided placed on the first end of the forming device and facing the second end. The means for extracting foam from the first and second suspensions through the foraminous elements to form a mesh on the foraminous elements are also included in the assembly of the head box. The means for extracting foam may include any of the conventional means used for this purpose, such as suction rolls, press rolls or other conventional structures. In a preferred embodiment, the first and second suction box assemblies are provided and mounted on the sides of the structure opposite the foraminous elements (see boxes 206 and 208 in FIGS. 13, 15 and 16). The mixed corrugated absorbent material can be incorporated as an absorbent center or as a storage layer in an absorbent article including, for example, a diaper or a feminine hygiene product. The mixed absorbent material can be used alone, or as illustrated in FIGS. 18 and 19, it can be used in combination with one or more other layers. FIGURE 18 illustrates the absorbent construction 30 in which the mixed material 10 is used as a storage layer in combination with an upper acquisition layer 32.

As shown in FIGURE 19 illustrating the construction 40, a third layer 42 (eg, a distribution layer) with the mixed material 10 and the acquisition layer 32 may also be used if desired. The mixed material Corrugated absorbent may also be incorporated as a liquid handling layer in an absorbent article such as a diaper. In an article as such, the mixed material can be used in combination with a storage center or layer. In the combination, the liquid handling layer may have a surface area that is smaller than, the same size as, or slightly larger than the surface area of the storage layer surface facing the mixed material corrugated. Representative absorbent constructions incorporating the fluted mixed material in combination with a storage layer are shown in FIGURES 20 and 21. Referring to FIGURE 20, the absorbent construction 90 includes the fluted mixed material 10 and the storage layer 60. The storage layer 60 is preferably a fibrous layer that includes absorbent material. The storage layer can be formed by any method including the methods of air deposition, wet deposition and foam formation. For constructions that include a storage layer and the fluted mixed material as a liquid handling layer, the absorbent material in the fluted mixed material may be the same, similar or different from the absorbent material in the storage layer.

In some embodiments, the corrugated absorbent composite material is asymmetrical in the sense that the front and front surfaces of the mixed material are not identical. In these embodiments, the mixed material has a first surface on which the absorbent material has been injected and an opposing surface (i.e., on the side of the machine) constituted substantially of fibers and which constitutes a surface of the fibrous base of the material mixed. For the absorbent constructions containing, in addition to the mixed grooved material, a storage layer, the mixed material can be oriented in two ways. In one embodiment, the fluted mixed material is oriented with its grooved surface directed towards the user. FIGURE 20 shows a representative construction 90 having a storage layer and the fluted mixed material with its grooved surface facing the user. Alternatively, as shown in FIGURE 21, the representative construction 92 includes the mixed material 10 having the channels of the mixed material directed towards the storage layer 60. The surface of the storage layer may or may not conform to the surface of the storage layer. mixed ribbed material. It is anticipated that rewetting of constructions including mixed ribbed material can also be reduced by incorporating synthetic fibers (eg, hydrophobic fibers such as polyester fibers) into the fibrous base of the mixed material. When used in combination with a storage layer, the fluted mixed material having a fibrous base including synthetic (hydrophobic) fibers is preferably incorporated in the inverted construction. To further increase the rewet performance, an acquisition layer can be combined with the fluted mixed material and the storage layer. FIGURES 22 and 23 illustrate absorbent constructions 94 and 96, respectively, each having acquisition layer 32 above the mixed material 10 and of the storage layer 60. The constructions 90, 92, 94 and 96 may further include the intermediate layer 70 to provide the constructions 100, 102, 104 and 106, shown in FIGURES 24A to 24 D, respectively. The intermediate layer 70 can be, for example, a layer of tissue paper, a non-woven layer, a pad deposited in the air or deposited in wet or a mixed grooved material. The constructions 90, 92, 94, 96, 100, 102, 104 and 106 can be incorporated into absorbent articles. Generally, absorbent articles 1 10, 1 12, 114, 1 16, 120, 122, 124 and 126, shown in FIGS. 25 A to 25 H, respectively, include a liquid-permeable front sheet 52 and a waterproof backsheet 54 to liquids and constructions 90, 92, 94, 96, 100, 102, 104 and 106, respectively. In such absorbent articles, the front sheet is attached to the back sheet. A variety of suitable constructions can be produced from the mixed absorbent material. The most common include absorbent products for the consumer, such as diapers, feminine hygiene products, such as feminine towels, and adult incontinence products. For example, with reference to FIGS. 26A and 26B, the absorbent article 50 includes the absorbent mixed material 10 and has a liquid-permeable front sheet 52 and a liquid-impermeable backsheet 54. As shown in FIGURE 26 B, the front sheet 52 is attached to the backsheet 54. Referring to FIGURE 27, the absorbent article 60 includes the absorbent blended material 10 and a surface acquisition layer 32. A front sheet 52 liquid permeable is above the acquisition layer 32 and a liquid-impermeable backing layer 54 below the mixed absorbent material 10. These mixed absorbent materials will provide advantageous liquid absorption performance to be used in, for example, diapers. FIGURE 28 illustrates the absorbent construction 70, which also includes the distribution layer 42 interposed between the acquisition layer 32 and the mixed material 10. As described above, the ribbed structure of the absorbent composite material aids in the transport of fluids and absorption in multiple wetting. One skilled in the art will be able to make a variety of different constructions using the concepts taught in the present invention. For example, FIGURE 29 shows a typical construction of an absorbent structure for adult incontinence. The article 80 includes the front sheet 52, the acquisition layer 32, the absorbent mixed material 10 and the back sheet 54. The front sheet 22 is liquid permeable, while the back sheet 24 is liquid impervious. In this construction, a liquid permeable tissue paper 44 made of a fibrous, polar material is placed between the absorbent composite material 10 and the acquisition layer 32. The present invention provides a fibrous absorbent composite material containing the absorbent material and the absorbent material. methods for its formation. The mixed absorbent material is a fibrous structure that includes absorbent material dispersed in strips along the length of the mixed material. Between the bands of absorbent material, the mixed absorbent material has continuously open distribution zones which exclude gel blocking in the mixed material. After the initial discharge of liquid, the mixed material develops channels that open the fibrous structure and increase the speed of fluid acquisition for subsequent discharges of liquids. The combination of channels and distribution zones allows for the complete utilization of the absorbent mixed material as a storage center when incorporated into an absorbent article such as a diaper. The mixed, corrugated absorbent material can be advantageously used as a handling layer or as a liquid storage layer in absorbent articles such as diapers. The following examples are provided for the purpose of illustrating, not limiting, the invention.

EXAMPLES EXAMPLE 1 Acquisition times for a representative corrugated absorbent mixed material In this example, the acquisition time for a corrugated absorbent composite material representative of the present invention (mixed material A) is compared with a commercially available diaper (diaper A, Kimberly-Clark). Also included in the comparison is an absorbent mixed material (mixed material B) having a composition similar to that of the mixed material of the invention and consisting of fibers (cross-linked fibers and southern pine pulp fibers in 50:50 ratio) , wet strength agent and absorbent material distributed relatively uniformly throughout the mixed material. The formation of the mixed material B is described in the provisional patent application E.U.A. Serial No. 60 / 046,395, filed on May 13, 1997, and in the international application with serial number PCT / US98 / 09682, filed on May 12, 1998, assigned to Weyerhaeuser Company, each expressly incorporated in the present invention for reference. The tests were carried out in commercially available diapers (Kimberly-Clark) from which the core layer and the moisture management layer were removed, and were used as surroundings for the mixed corrugated absorbent material and for the mixed B material. Test diapers were prepared by inserting the mixed corrugated absorbent material or the mixed material B into the diapers. The aqueous solution used in the tests is a synthetic urine available from National Scientific under the trade name RICCA. Synthetic urine is a saline solution that contains 135 meq./l of sodium, 8.6 meq./l of calcium, 7.7 meq./l of magnesium, 1.94% of urea by weight (based on total weight), plus other ingredients. A sample of the absorbent structure was prepared for the test by determining the core of the structure core, measuring 2.54 cm forward to the liquid application site and marking the spot with an "X". Once the sample was prepared, the test was carried out by first placing the sample on a plastic base (12.06 cm X 48.8 cm), and then placing a funnel acquisition plate (10.16 cm X 10.16 cm plastic plate). ) on top of the sample with the hole in the plate placed on the "X". Then a donut-shaped weight (1400 g) was placed on top of the funnel acquisition plate to which a funnel was then fixed (diameter of 10.16 cm). The acquisition of liquid was then determined by pouring 100 ml of synthetic urine into the funnel, and measuring the time from when the liquid was first introduced into the funnel until the time when the liquid disappeared from the bottom of the funnel in the sample. The time measured is the acquisition time for the first liquid discharge. After waiting for one minute, a second 100 ml portion was added to the funnel, and the acquisition time for the second discharge was measured. After waiting an additional minute, the acquisition was repeated for the third time to provide an acquisition time for the third download. The acquisition times reported in seconds for each of the three successive discharges of liquid of 100 ml for diaper A, mixed material B and mixed material A, are summarized in table 1.

TABLE 1 Comparison of acquisition time As shown in Table 1, the liquid is acquired more rapidly by the mixed absorbent material of the invention than by the commercially available diaper containing a storage core deposited in the air. The results show that the core deposited in the air does not acquire liquid as quickly as does the mixed wet deposited material of the invention. The commercial diaper also exhibited a characteristic decrease in the acquisition velocity in successive liquid discharges. In contrast, the mixed material of the invention showed a decrease in the acquisition time while the mixed material continued to absorb liquid in successive discharges. In a significative way, the absorbent composite material of the invention exhibits an acquisition time for the third discharge that is substantially less (approximately 10 times) than that of the commercially available diaper for the initial discharge. The results reflect the higher absorption capacity and capillary network for mixed materials deposited in wet compared to conventional storage cores deposited in the air in general, and the improved performance of the mixed corrugated absorbent material in particular. For the reasons indicated above, the acquisition time observed for the mixed material B deposited in the wet is also less than that of the core deposited in the air. The acquisition times for the mixed material B in successive discharges remains essentially constant. In contrast, the mixed material A has quite reduced acquisition times in the second and third discharges. The increased speed can be attributed to the band nature of the absorbent material in the mixed material. Therefore, the results demonstrate that even among the mixed materials wet deposited containing absorbent material, the configuration of the absorbent material within the mixed material is a significant factor in the acquisition of liquid. While the absorbent material homogenously distributed in a mixed material deposited in wet provides advantages over mixed materials deposited in the air having similar compositions, that the mixed wet deposited materials have bands of absorbent material provides additional significant advantages including increased liquid acquisition and persistent.

EXAMPLE 2 Acquisition and rewet speed for representative mixed corrugated absorbent materials In this example, the acquisition time and the rewetting of corrugated absorbent composite materials representative of the present invention (designated as mixed materials) are compared.

A1-A4), with a commercially available diaper (diaper A, Kimberly Clark).

The mixed materials A1-A4 are different by the method by which the mixed materials were dried. The comparison also includes a series of mixed absorbent materials (mixed materials B1-B4) formed as described above for the mixed material B in Example 1 and differing by the method by which they were dried. Certain properties of the mixed materials tested, including the amount of superabsorbent material (percent by weight of SAP) in the mixed material and the basis weight for each of the mixed materials, are summarized in Table 2. The tests were carried out in commercially available diapers (Kimberly Clark) from which the cores were removed and used as surroundings for mixed corrugated absorbent materials and for mixed materials B1-B4. The test diapers were prepared by inserting the tested mixed materials into the diapers. The acquisition time and rewetting are determined in accordance with the multiple dose rewet test described below. Briefly, the multi-dose rewet test measures the amount of synthetic urine released from an absorbent structure after each of three liquid applications, as well as the time required for each of the three doses of liquid to be absorbed into the product. . The aqueous solution used in the tests was a synthetic urine available from National Scientific under the trade name RICCA, as described above in Example 1. A pre-weighed sample of the absorbent structure was prepared for the test, determining the center of the core of the structure measuring 2.54 cm towards the front for the liquid application site, and marking the site with an "X". A liquid application funnel (minimum capacity of 100 ml, 5-7 ml / s flow rate) was placed 10.16 cm above the sample surface in the "X". Once the sample was prepared, the test was carried out as follows. The sample was flattened and the nonwoven side was placed up on the top of a table under the liquid application funnel. The funnel was filled with a dose (100 ml) of synthetic urine. A dosing ring (0.39 cm stainless steel, 5.08 cm ID x 7.62 cm height) was placed on the "X" marked on the samples. A first dose of synthetic urine was applied within the dosage ring. Using a stopwatch, the liquid acquisition time in seconds was recorded, from the time when the funnel valve was opened until the time the liquid was absorbed in the product, from the bottom of the dosing ring. After a 20 minute waiting period, rewetting was determined. During the 20 minute waiting period after the first dose was applied, a stack of filter papers (19-22 g, Whatman # 3, 1.0 cm or equivalent) that had been exposed to ambient humidity for a minimum was weighed. 2 hours before the test). The stack of pre-weighed filter papers was placed over the center of the moistened area. A cylindrical weight (8.9 cm in diameter, 4.44 Kg.) Was placed on top of these filter papers. After two minutes, the weight was removed, the filter papers were weighed, and the change in weight was recorded. The procedure was repeated twice more. A second dose of synthetic urine was added to the diaper and the acquisition time was determined, filter papers were placed on the sample for two minutes, and the change in weight was determined. For the second dose, the weight of the dry filter papers was 29-32 g, and for the third dose, the weight of the filter papers was 39-42 g. The dried papers of the previous dose were supplemented with additional dry filter papers. The liquid acquisition time is reported as the time (seconds) necessary for the liquid to be absorbed in the product for each of the three doses. The results are summarized in Table 2. Rewetting is reported as the amount of liquid (grams) absorbed back into the filter papers after each liquid dose (ie, the difference between the weight of the wet filter papers and the weight of dry filter papers). The results are also summarized in table 2.

TABLE 2 As indicated in Table 2, the acquisition times for representative mixed materials of the invention (mixed materials A1-A4) were significantly lower than for the commercially available core.

The rewetting of the representative mixed materials of the invention (mixed materials A1-A4), is significantly lower than for the other cores. Although the mixed materials initially exhibited relatively low rewetting, after the third discharge the commercially available core showed substantial rewet. In contrast, the mixed materials A continued to exhibit under rewetting.

EXAMPLE 3 Horizontal and vertical aption for a representative corrugated abent mixed material In this example, the aption characteristics of a representative corrugated abent composite material (mixed material A) were compared to the storage core of a commercially available diaper (B diaper, Procter &Gamble) and a wet deposited storage core it has an abent material distributed homogeneously through the mixed material (mixed material B). The horizontal aption test measures the time it takes for a liquid to wet horizontally preselected distances. The test was carried out by placing a mixed sample material on a horizontal surface with one end in contact with a liquid bath, and measuring the time necessary for the liquid to wet pre-selected distances. Briefly, a strip of mixed sample material (40 cm X 10 cm) was separated from a pulp sheet or other source. If the sheet has the address of the machine, the cut is made so that the length of 40 cm of the strip is parallel to the direction of the machine. For the abent composite materials of the invention, the strip is centered such that four bands of abent material are within the width of the strip. Starting at one end of the 10 cm wide strip, a first line was marked 4.5 cm from the edge of the strip, and then consecutive lines were marked at 5 cm intervals along the entire length of the strip ( that is, 0 cm, 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm and 35 cm). A horizontal aption apparatus having a central channel with horizontal level wings extending away from the opposite sides of the channel was prepared. The non-sustained edge of each wing was placed at the same level as the inner edge of the channel. At each end of the wing, a plastic extension is placed to hold each wing at a level and horizontal position. The channel was then filled with synthetic urine. The strip of mixed sample material was then bent gently at the 4.5 cm mark to form an angle of approximately 45 ° on the strip. The strip was then placed on the wing, so that the strip would be placed horizontally, and the folded end of the strip would extend into, and come into contact with, the liquid in the channel. The liquid aption was clocked starting from when the liquid reached the first line marked on the mixed material at 5 cm from the 4.5 cm fold. The aption time was then recorded at 5 cm intervals when 50 percent of the liquid front reached the marked range (e.g., 5 cm, 10 cm). The level of liquid in the channel was maintained at a relatively constant level throughout the test, replenishing it with additional synthetic urine. The results of horizontal aption are summarized in Table 3.

TABLE 3 Comparison of horizontal aption The results tabulated above indicate that horizontal aption is increased for mixed materials deposited wet compared to a core deposited in conventional air. While the aption time for the mixed material B is about 50 percent of that for the core of the conventional diaper, the aption time for the mixed material A is approximately 50 percent of that for the mixed material B. In this way, the horizontal absorption for the mixed material A is about 4 times that of a commercially available storage core. Such result indicates the effectiveness of the distribution zones of the mixed material of the present invention created by the nature in bands of the absorbent material. The vertical absorption test measures the time it takes for a liquid to vertically wet pre-selected distances. The test was carried out by vertically suspending a sample mixed material, one end of the mixed material being in contact with a liquid bath, and measuring the time necessary for the liquid to wet pre-selected distances. Before the test, mixed sample materials (10 cm X 22 cm) were separated and marked with consecutive lines of 1 cm, 1 1 cm, 16 cm and 21 cm from one of the edges of the strip. Preferably, the samples were preconditioned for 12 hours at 50 percent relative humidity and 23 ° C, and then stored in sample bags until testing. The mixed sample material was oriented vertically and was clamped from its upper edge to the 1 cm mark, and allowing its lower edge to come in contact with a bath containing synthetic urine. The timing started once the strip was put in contact with the liquid. The time required for 50 percent of the absorption front to reach 5 cm, 10 cm, 15 cm and 20 cm was then recorded. The results of vertical absorption are summarized in table 4.

TABLE 4 Comparison of vertical absorption As in the case of horizontal absorption results, the mixed materials A and B have significantly greater vertical absorption. In addition, as between the mixed materials A and B, the mixed material of the present invention can distribute the liquid away from the discharge more quickly than even that of the mixed wet deposited material having uniformly distributed absorbent material throughout. the mixed material. The results also show that the mixed wet deposited materials have significantly higher wet tensile strength compared to the mixed material deposited in conventional air.

EXAMPLE 4 Liquid distribution for a representative corrugated absorbent mixed material In this example, the liquid distribution in a corrugated absorbent mixed material (mixed material A) was compared to that of two commercially available diapers (diapers A and B above). The test measures the capacity of a diaper core to distribute the acquired fluid. The perfect distribution would have 0% deviation from the average. The ideal liquid distribution would result in an equal distribution of the liquid applied in each of the four distribution zones (ie, approximately 25% liquid in each zone). The distribution of liquid is determined by weighing different zones of a sample that have been subjected to the re-wetting test with multiple doses, described above in example 2. Basically, after the last rewetting, the diaper wings are removed and then cut into 4 distribution zones of equal length. Each zone is then weighed to determine the weight of the liquid contained in each zone. The liquid distribution results for a corrugated absorbent composite material representative of the invention approximate ideality. The results indicate that although commercial representative storage cores accumulate liquid near the discharge site, the liquid is efficiently and efficiently distributed along the storage core of the corrugated absorbent material. Although the preferred embodiments of the invention have been illustrated and described, it will be appreciated that various changes may be made therein without departing from the scope and scope of the invention. The embodiments of the invention over which the exclusive property or privilege is claimed are defined as follows:

Claims

NOVELTY OF THE INVENTION CLAIMS

1. - A mixed absorbent material, comprising a fibrous matrix and absorbent material, further characterized in that the absorbent material is within the fibrous matrix in one or more bands where the bands define liquid distribution zones in the fibrous matrix, and where the fibrous matrix comprises bound cellulosic fibers.

2. The mixed material according to claim 1, further characterized in that the distribution zones are substantially free of absorbent material.

3. The mixed material according to claim 1, further characterized in that the webs are continuous along the length in the machine direction.

4. The mixed material according to claim 1, further characterized in that the bands are substantially parallel.

5. The mixed material according to claim 1, further characterized in that the bands are discontinuous along the length of the mixed material in the machine direction.

6. The mixed material according to claim 1, further characterized in that the bands further comprise fibrous material.

7. - The mixed material according to claim 6, further characterized in that the fibrous material comprises fibers selected from the group consisting of elastic fibers, matrix fibers and mixtures thereof.

8. The mixed material according to claim 1, further characterized in that the fibrous material comprises fibers selected from the group consisting of elastic fibers, fibers of the matrix and mixtures thereof.

9. The mixed material according to claim 8, further characterized in that the elastic fibers are selected from the group consisting of chemically hardened fibers, sinuous fibers, chemithermomechanical pulp fibers, prehydrolyzed kraft pulp fibers, synthetic fibers and mixtures thereof .

10. The mixed material according to claim 9, further characterized in that the chemically hardened fibers comprise interwoven cellulosic fibers.

11. The mixed material according to claim 10, further characterized in that the interwoven cellulosic fibers are interlaced with an entanglement agent selected from the group consisting of urea-based interlacing agents and polycarboxylic acid.

12. The mixed material according to claim 9, further characterized in that the synthetic fibers are selected from the group consisting of polyolefin, polyester, polyamide and bicomponent and heat-settable fibers.

13. The mixed material according to claim 12, further characterized in that the polyester fibers are polyethylene terephthalate fibers.

14. The mixed material according to claim 8, further characterized in that the fibers of the matrix comprise cellulosic fibers.

15. The mixed material according to claim 14, further characterized in that the cellulosic fibers comprise fibers selected from the group consisting of wood pulp fibers, cotton fluff fibers, hemp fibers and mixtures thereof.

16. The mixed material according to claim 8, further characterized in that the elastic fibers are present in an amount of about 10 to about 60 weight percent of the total mixed material.

17. The mixed material according to claim 8, further characterized in that the elastic fibers are present in an amount of from about 10 to about 50 weight percent of the total mixed material.

18. The mixed material according to claim 1, further characterized in that the absorbent material is a superabsorbent material.

19. - The mixed material according to claim 18, further characterized in that the superabsorbent material is selected from the group consisting of superabsorbent particles and superabsorbent fibers.

20. The mixed material according to claim 1, further characterized in that the absorbent material is present in an amount of from about 0.1 to about 80 weight percent of the total mixed material.

21. The mixed material according to claim 1, further characterized in that the absorbent material is present in an amount of about 40 weight percent of the total mixed material.

22. The mixed material according to claim 1, further characterized in that the absorbent material absorbs from about 5 to about 100 times its weight in 0.9 percent saline.

23. The mixed material according to claim 1, further comprising a wet strength agent.

24. The mixed material according to claim 23, further characterized in that the wet strength agent is a resin selected from the group consisting of polyamide-epichlorohydrin and polyacrylamide resins.

25. The mixed material according to claim 23, further characterized in that the wet strength agent is present in the mixed material in an amount of from about 0.01 to about 2 weight percent of the total mixed material.

26. The mixed material according to claim 23, further characterized in that the wet strength agent is present in the mixed material at about 0.25 weight percent of the total mixed material.

27. The mixed material according to claim 1, with a basis weight of about 50 to about 1000 g / m2.

28.- The mixed material according to claim 1, with a density of about 0.02 to about 0.7 g / cm3.

29. The mixed material according to claim 1, further characterized in that the mixed material is formed by a wet deposition process.

30. The mixed material according to claim 1, further characterized in that the mixed material is formed by a foaming process.

31. The mixed material according to claim 1, further characterized in that the fibrous matrix comprises interwoven cellulosic fibers present in about 45 weight percent based on the total weight of the mixed material.

32. The mixed material according to claim 1, further characterized in that the fibrous matrix comprises wood pulp fibers present at about 15 weight percent based on the total weight of the mixed material.

33. - The mixed material according to claim 1, further characterized in that the fibrous matrix further comprises absorbent material.

34.- The mixed material according to claim 33, further characterized in that the absorbent material comprises superabsorbent material.

35.- An absorbent article comprising a mixed absorbent material including a fibrous matrix and absorbent material, wherein the absorbent material is within the fibrous matrix in bands, wherein the bands define liquid distribution zones in the fibrous matrix, and wherein the fibrous matrix comprises bound cellulosic fibers.

36. The absorbent article comprising: a liquid permeable lining sheet; a storage layer comprising a mixed absorbent material including a fibrous matrix and absorbent material, wherein the absorbent material is within the fibrous matrix in bands, wherein the bands define liquid distribution zones in the fibrous matrix, and in wherein the fibrous matrix comprises bound cellulosic fibers; and a waterproof backing sheet.

37. The absorbent article comprising: a liquid-permeable garnishing sheet; a capture layer to acquire and distribute liquid quickly; a storage layer comprising a mixed absorbent material including a fibrous matrix and absorbent material, wherein the absorbent material is within the fibrous matrix in bands, wherein the bands define liquid distribution zones in the fibrous matrix, and in wherein the fibrous matrix comprises bound cellulosic fibers; and a waterproof backing sheet.

38.- The absorbent article comprising: a liquid-permeable garnishing sheet; a capture layer to acquire and distribute liquid quickly; a storage layer comprising a mixed absorbent material including a fibrous matrix and absorbent material, wherein the absorbent material is within the fibrous matrix in bands, wherein the bands define liquid distribution zones in the fibrous matrix, and in wherein the fibrous matrix comprises bound cellulosic fibers; an intermediate layer interposed between the acquisition layer and the storage layer; and a waterproof backing sheet.

39.- The absorbent article according to claim 38, further characterized in that the intermediate layer is selected from the group consisting of a liquid permeable fabric and a distribution layer.

40.- The absorbent article according to claim 36, further characterized in that the article is a product for feminine hygiene.

41.- The absorbent article in accordance with the claim 40, further characterized in that the top sheet is attached to the backing sheet.

42. The absorbent article according to claim 37, further characterized in that the article is a diaper.

43. The absorbent article according to claim 42, further comprising leg folds.

44. The absorbent article comprising: a liquid-permeable garnishing sheet; a capture layer to acquire and distribute the liquid; a storage layer; and a liquid-impermeable backing sheet wherein the uptake layer a mixed absorbent material including a fibrous matrix and absorbent material, wherein the absorbent material is within the fibrous matrix in bands, wherein the bands define distribution zones of liquid in the fibrous matrix, and wherein the fibrous matrix comprises bound cellulosic fibers.

45. The absorbent article according to claim 44, further characterized in that the acquisition layer has a smaller surface area than the upper surface area of the storage core.

46. The absorbent article according to claim 44, further characterized in that the acquisition layer has a surface area greater than the upper surface area of the storage core.

47.- The absorbent article in accordance with the claim 44, further characterized in that the storage layer includes absorbent material.

48. The absorbent article according to claim 44, further characterized in that the storage layer includes mixed absorbent material comprising fibrous matrix urca and absorbent material, wherein the absorbent material is within the fibrous matrix in bands, wherein the bands define liquid distribution zones in the fibrous matrix, and wherein the fibrous matrix comprises bound cellulosic fibers.

49.- The absorbent article according to claim 44, further characterized in that the article is a diaper.

50. The absorbent article according to claim 44, further comprising leg folds.