JP2002529168A - Reticulated absorbent composite - Google Patents

Abstract

(57) Abstract: An absorbent composite having a reticulated core and a fiber layer is disclosed. The core and the layer are formed integrally. The layer is coextensive with the outer surface of the core. In one embodiment, the composite includes a layer on the opposite side of the outer facing surface of the core. The core includes a fiber matrix and an absorbent material. The fiber matrix defines voids and void passages, the voids being disposed throughout the composite. The absorbent material is partially disposed within the void. When wet, the absorbent material disposed within those voids is capable of expanding into the voids. Absorbent articles comprising the composite are also disclosed.

Description

DETAILED DESCRIPTION OF THE INVENTION

FIELD OF THE INVENTION The present invention relates to absorbent composites, and more particularly to reticulated absorbent composites comprising a superabsorbent material in a fibrous matrix.

[0002] Cellulose fibers derived from the background wood pulp invention various absorbent articles, e.g., diapers, have been used incontinence products, and in feminine hygiene products. For absorbent articles, in addition to having a high absorption capacity for liquids, it is desirable to have good dry and wet strength for durability and effective fluid management in use. The absorbent capacity of articles made of cellulosic fibers is often enhanced by adding superabsorbent materials, such as superabsorbent polymers. Superabsorbent polymers known in the art have the ability to absorb liquids 5 to 100 times their weight or more. Thus, the presence of the superabsorbent polymer generally increases the liquid holding capacity of the absorbent article made of cellulose.

Since superabsorbent polymers absorb liquids and swell upon contact with liquids, superabsorbent polymers have heretofore mainly been used in cellulose mats produced by the usual dry air-laid process. It has been incorporated. Because superabsorbent polymers tend to absorb and swell liquids during the formation of absorbent mats, and therefore require considerable energy to dry them completely, the Wetlaid methods are not used commercially.

[0004] Cellulose structures formed by wet laid processes are typically air-cooled.
Shows certain properties over that of the raid structure. The integrity, fluid distribution, and wicking properties of wet laid cellulosic structures are superior to those of air laid structures. Attempts to combine the benefits of wet laid composites with the high absorption capacity of superabsorbent materials have led to the formation of various wet laid absorbent composites, including superabsorbent materials. Generally, the superabsorbent materials contained in these structures are distributed as layers within the multilayer composite. In these structures, the superabsorbent polymers are relatively localized and are not evenly distributed throughout the absorbent structure, thus rendering their complexes susceptible to gel blocking. . Upon absorbing liquid, the superabsorbent materials tend to coalesce to form a gelatinous mass, which prevents the liquid from being pumped into the non-wetting portion of the composite. By blocking the distribution of the obtained liquid from the non-wetting portion of the composite, gel blocking makes effective and efficient use of superabsorbent materials in fibrous composites impossible. Such a decrease in the receptivity of the fibrous composite results from capillary acquisition with swelling of the superabsorbent material and narrowing of the distribution channel. The reduced absorption capacity and consequent loss of capillary distribution channels for conventional absorbent cores containing superabsorbent materials is represented by a reduced liquid acquisition rate, far from the ideal liquid distribution for a continuously rushing liquid. Things.

[0005] Accordingly, an absorbent composite comprising a superabsorbent material and effectively acquiring and sucking up liquid throughout the composite, effectively absorbing and retaining the acquired liquid There is a need for an absorbent composite that is distributed without gel blocking in the absorbing material. There is also a need for an absorbent composite that continuously acquires and distributes liquid throughout the composite with respect to the rushing liquid. In addition, an absorbent composite comprising a superabsorbent material, wherein the superabsorbent material has the advantages associated with wet laid composites including wet strength, absorption capacity and acquisition, liquid distribution, softness, and elasticity. There is a demand for the indicated absorbent composites. The present invention seeks to meet these needs and provides further related advantages.

SUMMARY OF THE INVENTION The present invention relates to a reticulated fibrous absorbent composite comprising an absorbent material. The absorbent composite is a fibrous matrix comprising an absorbent material and a three-dimensional network of channels or capillaries. The network of this composite enhances the distribution, acquisition and wicking of the provided liquid while providing the high absorption capacity of the absorbent material. Wet strength agent (Wet
A strength agent may be incorporated into the composite to provide wet integrity and to aid in the fixation of the absorbent material in the composite.

[0007] Absorbent composites formed in accordance with the present invention include a stable three-dimensional network of fibers and channels, which provides for rapid acquisition and wicking of liquid. These fibers and channels distribute the obtained liquid throughout the composite and direct the liquid to the absorbent material present in the composite where the liquid is ultimately absorbed. This complex retains its integrity before, during, and after the introduction of the liquid. In one embodiment, the composite is a densified composite that can recover its original volume when wet.

[0008] In one aspect, the invention provides an absorbent composite having a fiber matrix that includes an absorbent material. The fiber matrix defines voids and void channels that are distributed throughout the composite. The absorbent material is located in some voids. Absorbent material located in these voids can expand into the voids.

[0009] In one embodiment, the reticulated composite comprises at least one fibrous layer. For such an embodiment, the composite comprises a mesh core and a fiber layer adjacent and coextensive with the exterior facing surface of the core. The layers of the composite may comprise any suitable fiber or combination of fibers, and may be formed from the same or different fibers used to form the reticulated core.

[0010] In another aspect of the invention, a method is provided for forming a composite and an absorbent article comprising the composite. This absorbent article includes a consumer absorbent product, for example,
Includes diapers, women's care products, and adult incontinence products.

[0011] The absorbent composites formed in accordance DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is reticulated fibrous composite comprising an absorbent material. The absorbent material is distributed substantially throughout the fibrous composite and contributes to the absorption and retention of the liquid obtained by the composite. In a preferred embodiment,
The absorbent material is a super absorbent material. The fibers of the composite form channels or capillaries that, in addition to forming a matrix for the absorbent material, contribute to the acquisition of liquid in contact with the composite and distribution of the acquired liquid to the absorbent material. Provides a stable three-dimensional net. The composite may include a wet strength agent that further increases tensile strength and structural integrity into the composite.

[0012] The composite is a fiber matrix that includes an absorbent material. The fiber matrix defines voids and void channels that are distributed throughout the composite. The absorbent material is located in some voids. Absorbent material located in these voids can expand into the voids.

[0013] The absorbent composite can be used in a variety of absorbent articles, such as diapers and training pants; feminine care products including sanitary napkins, tampons, and pant liners; adult incontinence products; Surgical and dental sponges; bandages; food tray pads; and the like.

The composite is highly absorbent and has a high liquid storage capacity, so that it can be incorporated into an absorbent article as a liquid storage core. In such an arrangement, the composite can be combined with one or more other composites or layers, including, for example, an acquisition and / or distribution layer. In a preferred embodiment, the absorbent article, such as a diaper,
Includes an acquisition layer overlying the reticulated storage core and has a liquid permeable facing
A) a sheet and a liquid-impermeable backing sheet. Due to the ability to rapidly acquire and dispense liquid, the complex can function as a liquid management layer that acquires liquid and transports a portion of it to the underlying reservoir. Thus, in another embodiment,
The absorbent composite can be combined with a storage layer to provide an absorbent core that is useful in an absorbent article.

[0015] The absorbent composite formed according to the present invention is a reticulated absorbent composite. As used herein, the term "reticulated" refers to the openness and porosity of a composite characterized by having a stable three-dimensional network of fibers (i.e., a fiber matrix);
This three-dimensional network creates channels or capillaries that serve to rapidly acquire and distribute liquid throughout the composite and ultimately to transport the acquired liquid to absorbent material distributed throughout the composite.

The network composite has an open and stable structure. The open and stable structure of the fibrous composite includes a network of capillaries or channels that is effective in obtaining liquid and distributing it throughout the composite. In this composite, the fibers form a relatively dense bundle that directs fluid throughout the composite to the absorbent material distributed throughout the composite. The wet strength agent of the composite serves to stabilize the fiber structure by providing interfiber bonding. This inter-fiber bonding assists in providing a composite having a stable structure in which the capillaries or channels of the composite remain open before, during, and after the liquid is swept. Due to the stable structure of this complex,
Capillaries are provided that remain open after the first rush of liquid and are available for liquid acquisition and distribution during the next rush.

Referring to FIG. 1, an exemplary resorbable composite formed generally in accordance with the present invention, indicated generally by the reference numeral 10, comprises substantially fibers 16 and defining voids.
ds) a fiber matrix comprising a fiber region 12 comprising 14. Some voids contain absorbent material 18. The voids 14 are distributed throughout the composite 10.

A representative reticulated composite formed in accordance with the present invention is shown in FIGS. 2-9. These composites contain 48 weight percent of matrix fibers (ie, NB416).
Pine (Southern pine) commercially available from Weyerhaeuser Co. under the name
ine)), 12% by weight of elastic fibers (ie polymeric acid cross-linked fibers)
40% by weight of an absorbent material (ie, a superabsorbent material commercially available from Stockhausen), and about 0.5% by weight of a wet strength agent (ie, from Hercules under the name Kymene®). Commercially available polyamide-epichlorohydrin resin). FIG. 2 is a micrograph at 12 × magnification of a cross section of a typical composite formed by the wet laid method. FIG. 3 is a photomicrograph of the same cross section at 40 × magnification. FIG. 4 is a photomicrograph at 12 × magnification of a cross section of a typical composite formed by the foam method. FIG. 5 is a photomicrograph of the same cross section at 40 × magnification. The reticulation of these complexes is shown in these figures. Referring to FIG. 3, the fiber region extends throughout the composite, creating a network of channels. Void regions, including those containing the absorbent material, appear throughout the composite and are in fluid communication with the fiber regions of the composite. The absorbent material is found in the voids of the composite and is generally surrounded by high density fiber bundles.

Photomicrographs of the representative composites shown in FIGS. 2-5 in the wet state are:
This is shown in FIGS. 6-9. These micrographs were obtained by cutting the lyophilized complex obtaining synthetic urea under free swelling conditions. 6 and 7 are photomicrographs of the wet wet laid composite at 8 × and 12 × magnification, respectively.
8 and 9 are micrographs of the wet foam forming composite at 8 × and 12 × magnification, respectively. Referring to FIG. 6, the absorbent material in the wet composite is swollen, increasing in size and more completely occupying the voids previously occupied by the absorbent material in the dry composite.

[0020] The fiber matrix of the composite mainly comprises fibers. In general, the fibers
About 20 to about 90 weight percent in the composite, based on the total weight of the composite;
Preferably it is present in an amount of about 50 to about 70 weight percent. Fibers suitable for use in the present invention are known to those of skill in the art and include any fiber capable of forming a wet composite.

[0021] The composite includes elastic fibers. As used herein, the term "elastic fiber" refers to a fiber present in a composite that imparts reticulation to the composite. In general, elastic fibers provide a composite having bulk and elasticity. The incorporation of elastic fibers into the composite allows the composite to expand upon absorption of liquid without loss of structural integrity. In addition, elastic fibers offer advantages in the composite formation process. Because of the porous and open structures resulting from the wet composites containing elastic fibers, these composites are relatively easy to drain and, therefore, dehydrate and dry more easily than wet composites without elastic fibers. In one embodiment,
The composite comprises about 5 to about 60, based on the total weight of the composite, elastic fibers.
Weight percent, preferably about 10 to 40 weight percent.

The elastic fibers include cellulose fibers and synthetic fibers. Elastic fibers include chemically cured fibers, flexible fibers, and chemically-thermo-pulp (chemithermomechanical pulp).
) (CTMP), and pre-hydrolyzed kraft pulp (PHKP).

The term “chemically cured fibers” refers to fibers that have been cured by chemical means to increase stiffness under dry and wet conditions. The fibers can be cured by adding a chemical curing agent that can coat and / or impregnate the fibers. Curing agents include polymeric wet strength agents, including resinous agents, such as polyamide-epichlorohydrin and polyacrylamide, described below. The fibers can also be cured by modifying the structure of the fibers, for example by chemical crosslinking. In one embodiment, the chemically cured fibers are intra-fiber cross-linked cellulose fibers.

Elastic fibers can include non-cellulosic fibers, including, for example, synthetic fibers such as polyolefin, polyamide, and polyester fibers. In one embodiment, the elastic fibers include cross-linked cellulosic fibers.

As used herein, the term “flexible fiber” refers to a cellulose fiber that has been chemically treated. Flexible fibers include, for example, fibers that have been treated with ammonia.

[0026] In addition to the elastic fibers, the composite includes matrix fibers. As used herein, the term "matrix fiber" refers to a fiber that can form hydrogen bonds with other fibers. Matrix fibers are included to provide strength to the composite. Matrix fibers include cellulosic fibers such as wood pulp fibers, high purity cellulosic fibers, and high surface area fibers such as expanded cellulosic fibers.
Other suitable cellulosic fibers include cotton linters, cotton fibers, and hemp fibers, among others. Mixtures of fibers can also be used. In one embodiment, the composite comprises matrix fibers in an amount of about 10 to about 60 weight percent, preferably about 20 to about 50 weight percent, based on the total weight of the composite.

The composite may include a combination of elastic and matrix fibers. In one embodiment, the composite comprises elastic fibers in an amount of about 5 to about 20 weight percent and matrix fibers in an amount of about 20 to about 60, based on the total weight of the composite.
Include in weight percent amount. In another embodiment, the composite comprises about 10 to about 15 weight percent of elastic fibers, preferably crosslinked cellulosic fibers, and about 40 to about 50 weight percent of matrix fibers, based on the total weight of the composite. , Preferably wood pulp fibers.

[0028] Cellulose fibers are the basic component of the absorbent composite. Cellulose fibers are derived primarily from wood pulp, although available from other sources. Wood pulp fibers suitable for use in the present invention can be obtained from known chemical processes, for example, with or without subsequent bleaching, kraft and sulfite processes. Pulp fibers can also be treated by thermomechanical, chemical thermomechanical, or a combination thereof. Preferred pulp fibers are produced by a chemical method. Ground wood fibers, recycled or secondary wood pulp fibers, and bleached and unbleached wood pulp fibers can be used. Softwoods and hardwoods can be used. Details of the choice of wood pulp fibers are known to those skilled in the art. These fibers are commercially available from a number of companies, including the assignee of the present invention, the Weyerhaeuser Company. For example, a suitable cellulosic fiber manufactured from Pinus pine that can be used in the present invention is CF4 from Weyerhaeuser Company.
16, NF405, PL416, FR516, and NB416.

[0029] Wood pulp fibers can also be pre-treated prior to use in the present invention. This pre-treatment may include a physical treatment, such as steam treatment of the fibers or a chemical treatment, such as crosslinking of the cellulosic fibers using any one of a variety of crosslinking agents.
Crosslinking can increase the bulk and elasticity of the fiber, thereby improving the absorbency of the fiber. Generally, the crosslinked fibers are twisted or crimped. By using cross-linked fibers, it is possible to make the composite more elastic, softer, bulkier, have better wicking, and have a higher density than the composite without cross-linked fibers It becomes easier. Suitable crosslinked cellulose fibers made from pine pine are
Available from Weyerhaeuser Company under the name NHB416. Crosslinked cellulosic fibers and methods for their preparation are described in US Pat. No. 5,437,418 issued to Graef et al.
And No. 5,225,047, which are expressly incorporated herein by reference.

[0030] Intra-fiber crosslinked cellulose fibers are prepared by treating the cellulose fibers with a crosslinking agent. Suitable cellulosic crosslinkers include aldehyde and urea based formaldehyde additive products. For example, U.S. Patent Nos. 3,224,926; 3,241,533
No. 3,932,209; No. 4,035,147; No. 3,756,913; No. 4,689,118;
U.S. Pat. No. 4,440,135 issued to Chung; U.S. Pat. No. 4,935,022 issued to Lash et al .; U.S. Pat. No. 4,889,5 issued to Herron et al.
U.S. Pat. No. 3,819,470 issued to Shaw et al .; U.S. Pat. No. 3,658,613 issued to Steijer et al .; and U.S. Pat. No. 4,853,086 issued to Graef et al.
(See, all of which are expressly incorporated herein by reference in their entirety.) Cellulose fibers have also been crosslinked with carboxylic acid crosslinking agents containing polycarboxylic acids. U.S. Patent No. 5,137,537; No. 5,183,707; and the No. 5,190,563, C ₂ -C ₉ polycarboxylic acids that contain at least three carboxyl groups (e.g., citric acid and oxydisuccinic acid) used as a crosslinking agent is described ing.

Suitable urea-based crosslinkers include methylolated ureas, methylolated cyclic ureas,
Includes methylolated lower alkyl cyclic ureas, methylolated dihydroxy cyclic ureas, dihydroxy cyclic ureas, and lower alkyl substituted cyclic ureas. Particularly preferred urea-based crosslinkers include dimethyldihydroxyethylene urea (DMeDHEU,
1,3-dimethyl-4,5-dihydroxy-2-imidazolidinone), dimethylol dihydroxyethylene urea (DMDHEU, 1,3-dihydroxymethyl-
4,5-dihydroxy-2-imidazolidinone), dimethylol urea (DMU,
Bis [N-hydroxymethyl] urea), dihydroxyethylene urea (DHEU,
4,5-dihydroxy-2-imidazolidinone) and dimethylol ethylene urea (DMEU, 1,3-dihydroxymethyl-2-imidazolidinone).

Suitable polycarboxylic acid crosslinkers include citric, tartaric, malic, succinic,
Glutaric acid, citraconic acid, itaconic acid, tartaric acid monosuccinic acid, and maleic acid are included. Other polycarboxylic acid crosslinking agents include polymeric polycarboxylic acids such as poly (acrylic acid), poly (methacrylic acid), poly (maleic acid), poly (maleic acid)
(Methyl vinyl ether-co-maleate) copolymer, poly (methyl vinyl ether-itaconate) copolymer, acrylic acid copolymer, and maleic acid copolymer. The use of polymeric polycarboxylic crosslinkers, such as polyacrylic acid polymers, polymaleic acid polymers, copolymers of acrylic acid, and copolymers of maleic acid, was filed on December 12, 1997 and filed with the Weyerhaeuser Company. No. 08 / 989,697, assigned to the assignee. Mixtures or blends of crosslinking agents can also be used.

The cross-linking agent may include a catalyst to promote a bonding reaction between the cross-linking agent and the cellulose fiber. Suitable catalysts include acid salts such as ammonium chloride, ammonium sulfate, aluminum chloride, magnesium chloride, and alkali metal salts of phosphorus-containing acids.

Although not to be construed as limiting, examples of fiber pretreatment include the application of surfactants or other liquids that modify the surface chemistry of the fiber. Other pretreatments include the incorporation of antimicrobial agents, pigments, dyes and densifying or softening agents. Other chemicals,
For example, fibers pretreated with a thermoplastic resin and a thermosetting resin can also be used. A combination of pre-processing can also be used. Similar treatment can be applied in a post-treatment process after formation of the composite.

Cellulosic fibers treated with particle binders and / or densifying / softening aids known in the art can also be used according to the present invention. The particle binder serves to attach another material, such as a cellulose fiber superabsorbent polymer, to the cellulose fibers. Cellulose fibers treated with suitable particle binders and / or densification / softening aids and processes for combining them with cellulose fibers are disclosed in the following U.S. Patents: (1) "Polymeric Binders for Binding Particles". t
US Patent 5,543,215 entitled "Fibers"; (2) "Non-Polymeric Organic
U.S. Patent No. 5,538,783 entitled "Binders for Binding Particles to Fibers"; (3) "Wet Laid Fiber Sheet Manufacturing With Reactivatable Binders f
US Patent No. 5,300,192 entitled "Or Binding Particles to Binders";
US Patent No. 5,352,480 entitled "Method for Binding Particles to Fibers Using Reactivatable Binders"; (5) "Particle Binders for High-Bulk Fib
US Patent 5,308,896 entitled "ers"; (6) "Particle Binders that Enhan.
US Patent No. 5,589,256 entitled "ce Fiber Densification"; (7) "Particle
US Patent No. 5,672,418 entitled "Binders"; (8) "Particle Binding to Fi.
US Patent No. 5,607,759 entitled "Bers"; (9) "Binders for Binding Water.
U.S. Pat. No. 5,693,411 entitled "Soluble Particles to Fibers"; (10) "P
US Patent No. 5,547,745 entitled "article Binders"; (11) "Particle Bind
US Patent 5,641,561 entitled "ing to Fibers"; (12) "Particle Binder.
U.S. Pat. No. 5,308,896 entitled "S for High-Bulk Fibers"; (13) "Polyet
US Patent No. 5,498, entitled "Hylene Glycol as a Binder Material for Fibers"
U.S. Pat. No. 5,609,727 entitled "Fibrous Product for Binding Particles"; (15) "Reactivatable Binders for Binding Particles to".
US Patent No. 5,571,618 entitled "Fibers"; (16) "Particle Binders for
U.S. Patent No. 5,447,977 entitled "High Bulk Fibers"; (17) "Absorbent Ar
US Patent No. 5, entitled "ticles Containing Binder Carrying High Bulk Fibers"
U.S. Pat. No. 5,789,32 entitled "Binder Treated Fibers".
No. 6, No. 6, and (19) U.S. Pat. No. 5,611,885 entitled "Particle Binders", which is expressly incorporated herein by reference in its entirety.

In addition to natural fibers, polymer fibers, for example, synthetic fibers, including polyolefin, polyamide, polyester, polyvinyl alcohol, and polyvinyl acetate fibers, can also be used in the absorbent composite. Suitable polyolefin fibers include polyethylene and polypropylene fibers. Suitable polyester fibers include polyethylene terephthalate fibers. Other suitable synthetic fibers include, for example,
Contains nylon fibers. Absorbent composites can include a combination of natural and synthetic fibers.

In one embodiment, the absorbent composite is a wood pulp fiber (eg, Weyerhaeus
er name NB416) and cross-linked cellulose fibers (for example, Weyerhaeuser name NH
B416). Wood pulp fibers are present in such combinations in an amount of about 10 to about 85 weight percent, based on the total weight of the fiber.

When incorporated into an absorbent article, the reticulated absorbent composite serves as a reservoir for the acquisition liquid. To efficiently retain the acquired liquid, the absorbent composite includes an absorbent material. As used herein, the term "absorbent material" refers to a material that absorbs liquid and generally has a greater absorption capacity than the cellulosic fiber component of the composite. Preferably, the absorbent material is water-swellable, generally at least about 5 times its weight in saline (eg, 0.9 percent saline),
A water-insoluble polymeric material desirably capable of absorbing about 20 times, preferably about 100 times or more. The absorbent material is swellable in the dispersion medium utilized to form the composite in this manner. In one embodiment, the absorbent material is untreated and swellable in the dispersion medium. In another embodiment, the absorbent material is a coated absorbent material that resists water absorption during the composite formation process.

[0039] The amount of absorbent material present in the composite can generally vary depending on the intended use of the composite. The amount of absorbent material present in the absorbent article, such as an absorbent core for an infant diaper, can range from about 5 to about 60 weight percent, preferably from about 30 to about 50 weight percent, based on the total weight of the composite. It is suitably present in the complex in percent amounts.

[0040] Absorbable materials 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, polyacrylamide, polyvinyl alcohol, ethylene maleic anhydride copolymer, polyvinyl ether, hydroxypropyl cellulose, among others.
Includes polyvinyl morpholinone, polymers and copolymers of vinyl sulfonic acid, polyacrylates, polyacrylamides, and polyvinyl pyridine. In one embodiment, the absorbent material is a super absorbent material. As used herein, "superabsorbent material" refers to a polymeric material that is capable of absorbing large amounts of fluid by swelling and forming a hydrogel (ie, hydrogel). In addition to absorbing large volumes of fluid, superabsorbent materials can also retain significant amounts of bodily fluids under moderate pressure.

Superabsorbent materials generally fall into three classes: starch graft copolymers, crosslinked carboxymethylcellulose derivatives, and modified hydrophilic polyacrylates.
Examples of such absorbent polymers include hydrolyzed starch-acrylonitrile graft copolymer, neutralized starch-acrylic acid graft copolymer, saponified acrylate-vinyl acetate copolymer, hydrolyzed acrylonitrile copolymer Alternatively, an acrylamide copolymer, a modified crosslinked polyvinyl alcohol, a neutralized self-crosslinked polyacrylic acid, a crosslinked polyacrylate salt, a carboxylated cellulose, and a neutralized crosslinked isobutylene-maleic anhydride copolymer are included.

Superabsorbent materials are commercially available, for example, from Clariant of Virginia
Portsmouth polyacrylate. These superabsorbent polymers are delivered in a variety of sizes, forms, and absorption properties (IM3500 and IM39 from Clariant)
00 available under the trade name). Another superabsorbent material is the trademark SANWET (Sanyo Kase
i Kogyo Kabushiki Kaisha) and SXM77 (Stockhausen of Greens)
boro, supplied by North Carolina). Other superabsorbent materials are disclosed in U.S. Patent No. 4,160,059; U.S. Patent No. 4,676,784; U.S. Patent No. 4,673.402;
U.S. Pat. No. 5,002,814; U.S. Pat. No. 5,057,166; U.S. Pat.
And U.S. Patent No. 4,818,598, all of which are expressly incorporated herein by reference. Products such as diapers incorporating superabsorbent materials are described in U.S. Pat. Nos. 3,699,103 and 3.670,731.

Suitable superabsorbent materials useful in the absorbent composite include superabsorbent particles and superabsorbent fibers. In one embodiment, the absorbent composite swells relatively slowly for the production of the composite and allows the composite or any construct containing the composite to not adversely affect the absorbency. Includes a superabsorbent material that swells at a gain rate. Generally, smaller absorbent materials will absorb liquid more quickly.

The absorbent composite may include a wet strength agent. Wet strength agents increase the strength of the absorbent composite and increase the wet integrity of the composite. In addition to increasing the wet strength of the composite, the wet strength agent can assist in binding the absorbent material, eg, superabsorbent material, in the fiber matrix of the composite.

[0045] Suitable wet strength agents include cationically modified starches having nitrogen-containing groups (eg, amino groups), for example, National Starch and Chemical Corp., Bridgewa.
ter, available from NJ; latex; wet strength resins such as polyamide-epichlorohydrin resins (e.g., Kymene (R) 557LX, Hercul)
es, Inc., Wilmington, DE), polyacrylamide resins (e.g., as described in U.S. Patent No. 3,556,932 issued to Coscia et al. on January 19, 1971;
For example, commercially available polyacrylamide marketed under the trade name Parez® 631 NC by American Cyanamid Co., Stanford, CT); urea and melamine formaldehyde resins, and polyethyleneimine resins. . A general discussion of wet strength resins utilized in the papermaking field and generally applicable in the present invention can be found in the TAPPI monograph series N
o. 29, "Wet Strength in Paper and Paperboard", Technical Association of
It can be found in the Pulp and Paper Industry (New York, 1965).

Generally, the wet strength agent is present in the composition in an amount of about 0,0% based on the total weight of the complex.
. It is present in an amount from 01 to about 2 weight percent, preferably from about 0.1 to about 1 weight percent, more preferably from about 0.3 to about 0.7 weight percent. In a preferred embodiment, the wet strength agents useful in forming the complex are Hercu
Polyamide commercially available from K. les, Inc. under the name Kymene®
Epichlorohydrin resin. The wet and dry tensile strength of absorbent composites formed in accordance with the present invention generally increases with increasing amounts of wet strength agent. The tensile strength of a representative composite is described in Example 7.

The absorbent composite generally has a basis weight of about 50 to about 1000 g / m ² , preferably about 200 to about 800 g / m ² . In one embodiment, the absorbent composite has a basis weight of about 300 to about 600 g / m ^2. The absorbent composite generally has a density from about 0.02 to about 0.7 g / cm ³ , preferably from about 0.04 to about 0.3 g / cm ³ . In one embodiment, the absorbent composite has a density of about 0.15 g / cm ^3.

In one embodiment, the absorbent composite is a densified composite. Densification methods useful in making densified composites are known to those skilled in the art. For example, U.S. Patent No.
No. 5,547,541 and filed May 21, 1997, entitled "Softened Fibers and Me
See patent application 08 / 859,743, assigned to Weyerhaeuser Company, entitled "thods of Softening Fibers,", both of which are expressly incorporated herein by reference. Densified absorbent reticulated storage after drying The complex is generally about 0
. It has a density of 1 to about 0.5 g / cm ³ , preferably about 0.15 g / cm ³ . Densification before drying can also be used. In one embodiment, the absorbent composite is densified by either heating or a room temperature calender roll method. See, for example, U.S. Patent Nos. 5,252,275 and 5,324,575, both of which are expressly incorporated herein by reference.

The composition of the reticulated absorbent composite can be varied to accommodate the needs of the desired end product into which it can be incorporated. In one embodiment, the absorbent composite comprises about 60 weight percent cellulosic fibers (about 48 weight percent wood pulp fibers and about 12 weight percent crosslinked cellulose fibers), about 40 weight percent, based on the total weight of the composite. Weight percent of absorbent material (eg, superabsorbent particles),
And about 0.5 weight percent of a wet strength agent (eg, polyamide-epichlorohydrin resin, Kymene®, about 10 pounds resin per ton of fiber).

The reticulated absorbent composite can be formed by wet laid and foam methods known to those having ordinary skill in the pulping art. A typical example of the wet laid method is “Wetlaid Fiber Sheet Manufactur” issued on April 5, 1994.
ing with Reactivatable Binders for Binding Particles to Fibers ", which is expressly incorporated herein by reference. Wet laid methods are described in standard textbooks such as Casey, PUL
P AMD PAPER, 2nd edition, 1960, Volume II, Chapter VIII-Sheet Formatio
Also described in n. Representative foam methods useful in forming composites are known in the art and include U.S. Pat. No. 3,716,449
No. 3,839,142; No. 3,871,952; No. 3,937,273; No. 3,938,782; No. 3,947,315; No. 4,166,090; No. 4,257,754; and No. 5,215,627, and the "Radfoam process" an Aque
ous Foam as a Fiber-Suspending Medium in Quality Papermaking, " Foams , Pr
oceedings of a Symposium organized by the Society of Chemical Industry,
Colloid and Surface Chemistry Group, RJ Akers, Ed., Academic Press, 19
76, all of which are expressly incorporated herein by reference.

In these methods, the absorbent material is incorporated into the composite during formation of the composite. In general, methods for forming a reticulated absorbent composite involve combining the components of the composite in a dispersion medium (eg, an aqueous medium) to form a slurry, and then mixing the slurry with a porous support (eg, Depositing on a forming wire and dewatering to form a wet composite. By drying the wet composite, a network composite is obtained.

As mentioned above, the network composite is prepared from the fibers, the absorbent material, and, optionally, the wet strength agent in the dispersion medium. In one embodiment of the method, the slurry is formed by directly combining the fibers, absorbent material, and wet strength agent in a dispersion medium. In another embodiment, the fiber and wet strength agent are first combined in a dispersion medium to obtain a fiber slurry, and then, in a second step, the slurry is prepared by adding an absorbent material thereto. In yet another aspect, the fiber slurry is combined with a second slurry containing an absorbent material, and the combined slurry is then deposited on a support. Instead, the individual slurries, eg, the slurry containing the fiber slurry and the absorbent material, are added to the split headbox (divi
A ded headbox can be deposited on a perforated support by using, for example, a twin slice headbox in which two slurries are simultaneously deposited on the support.

In one embodiment, a slurry (one or more) containing the components of the composite in a dispersion medium is deposited on a perforated support. Once deposited on the support, begin to drain the dispersion medium from the deposited fiber slurry. Removal (eg, dewatering) of the dispersion medium from the deposited fiber slurry may be continued, for example, by applying heat, pressure, vacuum, and combinations thereof, thereby resulting in the formation of a wet composite.

By drying the wet composite, a net absorbent composite can be finally produced. By drying, the remaining dispersion medium is removed, and an absorbent composite having a desired water content can be obtained. Generally, the conjugate has a moisture content of less than about 20 percent of the total weight of the conjugate, and in one embodiment, has a moisture content in the range of about 6 to about 10 weight percent. Suitable composite drying methods include, for example, the use of drying cans, air floats, and air dryers. Other drying methods and equipment known in the pulp and paper industry can also be used. Drying temperatures, pressures, and times are typical of the equipment and methods used and are known to those skilled in the pulp and paper industry. A representative wet laid method for forming a reticulated absorbent composite is described in Example 1.

For the foam method, the fiber slurry is a foam dispersion further including a surfactant. Suitable surfactants include ionic, non-ionic, and amphoteric surfactants known in the art. A representative foam method for forming a reticulated absorbent composite is described in Example 2.

By depositing the components of the absorbent composite on a perforated support, followed by dehydration, the wet composite comprising the absorbent material, which may absorb water and thus swell in size, is formed. It is formed. The wet composite comprising the water-swellable absorbent material can be dispensed onto a support from which water (ie, the dispersing medium) can be removed to dry the wet composite. Drying causes dehydration and size reduction of the water-swellable absorbent material, thereby creating voids in the composite surrounding the absorbent material.

In these methods, the absorbent material is preferably less than about 20 times its weight in the dispersion medium, more preferably less than about 10 times, and even more preferably less than about 5 times its weight in the dispersion medium. Absorbs.

The foam method is advantageous for forming absorbent composites for several reasons. In general, the foam process results in a fibrous web having both relatively low density and relatively high tensile strength. For webs comprising substantially the same components, the foam-forming web generally has a density greater than an air-laid web and less than a wet-laid web. Similarly, the tensile strength of the foam formed web is substantially greater than the air laid web and approaches the strength of the wet laid web. Also, the use of foam forming techniques allows for the size of pores and voids, the size of voids to be maximized, the orientation and uniform distribution of fibers, and the wide range of materials (eg, It is possible to better control the incorporation of long fibers and synthetic fibers which cannot be incorporated into the fibers.

For assembly, the resorbable composite is foamed, preferably using the Ahlstrom Comp
any (Helsinki, Finland). The method includes the desired manufacturing efficiency while producing a product with the desired performance characteristics.

The formation of reticulated absorbent composites by representative wet laid and foam methods is described in Examples 1 and 2, respectively. The absorption properties (ie, rewet, acquisition time, liquid distribution, dry strength, and elasticity) of a representative reticulated absorbent composite are shown in Example 3.
And 4. The wicking and liquid distribution of representative absorbent composites are described in Examples 5 and 6, respectively. The tensile strength of a representative composite formed in accordance with the present invention is described in Example 7. Typical wet laid and foam forming composite flexibility (ie, Taber stiffness)
Is described in Example 8.

One of the variables that affects the performance characteristics of an absorbent composite, including, for example, the rate of liquid acquisition and dispensing and the absorption capacity, is the degree of swelling of the absorbent material in the composite. These methods take into account the control and variation of the swelling of the absorbent material. The swelling of the absorbent material generally depends on the degree of its crosslinking (eg, surface and internal crosslinking) and the amount of water absorbed by the absorbent material. The degree of swelling depends on the type of absorbent material, the concentration of the absorbent material in the aqueous environment (eg, dispersion media and wet composites),
And the length of time the absorbent material remains in contact with such an environment. Generally, the lower the concentration of the absorbent material in the aqueous medium and the longer the contact time, the greater the swelling of the absorbent material. Swelling of the absorbent material can be minimized by dispersing the absorbent in cold water.

In general, the greater the initial swelling of the absorbent material, the greater the void volume, and therefore the lower the density of the resulting absorbent composite. The greater the void volume of the composite, the faster its liquid acquisition rate and, in general, the greater the absorption capacity of the composite.

As described above, the voids of the composite may cause hydration and swelling of the absorbent material (ie, during formation of the wet composite) and subsequent dehydration and size reduction of the absorbent material (ie, the wet composite). During drying). Ultimately, the density of the composite depends on the extent to which the absorbent material absorbs and swells the liquid during formation of the wet composite, and the conditions of drying the wet composite into which the swellable absorbent material is incorporated. Depends on the degree. Water absorbed by the absorbent composite during formation of the wet composite is removed from the absorbent material by drying the wet composite, thereby reducing its size. Dewatering the swellable absorbent material defines some of the voids in the fiber composite.

The reticulated absorbent composite can be incorporated as an absorbent core or storage layer into absorbent articles including, for example, diapers or feminine care products, the absorbent composite can be used alone, or As shown in FIGS. 10 and 11, it can be used in combination with one or more other layers. In FIG. 10, the absorbent composite 10 is used as a storage layer in combination with the upper acquisition layer 20. As shown in FIG.
If desired, the third layer 30 (eg, distribution layer) can be combined with the absorbent composite 10 and acquisition layer 2.
It can be used together with 0.

Various suitable absorbent articles can be made from the absorbent composite. The most common include absorbent consumer products such as diapers, feminine hygiene products such as feminine napkins, and adult incontinence products. For example, referring to FIG. 12A, an absorbent article 38 includes a composite 10, a liquid permeable facing sheet 22, and a liquid impermeable backing sheet 24. Referring to FIG. 12B, the absorbent article 40 includes the absorbent composite 10 and the overlay acquisition layer 20. Liquid permeable facing
Sheet 22 is the upper layer of acquisition composite 20 and is liquid impermeable backing sheet 24.
Is the lower layer of the absorbent composite 10. Absorbent composites provide advantageous liquid absorption performance for use in, for example, diapers. The network of the absorbent composite aids in fluid transport and absorption in multiple wets. For absorbent articles into which the composite is incorporated and which is suitable for use as a diaper or incontinence product, those articles may further include leg gathers.

The construct in FIGS. 12A and 12B is shown to illustrate a typical absorbent article, such as a diaper or feminine napkin. Those skilled in the art will be able to make a variety of different constructs using the concepts taught herein. A typical configuration of an exemplary absorbent structure for adult incontinence is shown in FIG. Article 50 includes facing sheet 22, acquisition layer 20, absorbent composite 10, and backing sheet 24. Facing sheet 22 is permeable to liquids, while backing sheet 24 is impermeable to liquids. In this configuration, the liquid-permeable woven fabric 26 comprising the polar fiber material comprises the absorbent composite 10 and the acquisition layer 2.
0.

Referring to FIG. 14, another absorbent article includes a facing sheet 22 and an acquisition layer 2.
0, an intermediate layer 28, an absorbent composite 10, and a backing sheet 24. Intermediate layer 28 includes, for example, a densified fibrous material, such as a combination of cellulose acetate and triacetin that is combined prior to forming the article. Thus, the intermediate layer 28 may be bonded to both the absorbent composite 10 and the acquisition layer 20 to form an absorbent article that is significantly more integrated than one in which the absorbent composite and the acquisition layer are not bonded to each other. it can. The hydrophilicity of layer 28 can be adjusted in such a way as to create a hydrophilic gradient between layers 10, 28 and 20.

[0068] The reticulated absorbent composite can also be incorporated as a liquid management layer in an absorbent article such as a diaper. In such articles, the composite can be used in combination with a storage core or layer. In this combination, the liquid management layer can have a top surface area that is less than, the same size as, or greater than the top surface area of the storage layer. A representative absorbent construct incorporating a reticulated absorbent composite in combination with a storage layer is shown in FIG. Referring to FIG. 15, the absorbent construct 70 includes the network composite 10 and the storage layer 72. Storage layer 72 is preferably a fibrous layer containing an absorbent material. This storage layer can be formed by any method, including airlaid, wet laid, and foam forming methods. The storage layer can be a network composite.

The acquisition layer can be combined with the network composite and the storage layer. FIG. 16 shows an absorbent construct 80 with the composite layer 10 and the acquisition layer 20 overlying the storage layer 72. The construct 80 may further include an intermediate layer 74 to provide the construct 90 shown in FIG. The intermediate layer 74 can be, for example, a woven layer, a non-woven layer, an air-laid or wet laid pad, or a mesh composite.

[0070] The constructs 70, 80, and 90 can be incorporated into an absorbent article. In general, the absorbent articles 100, 110, and 120 shown in FIGS. 18-20 include a liquid permeable facing sheet 22, a liquid impermeable backing sheet 24, and constructs 70, 80, and 90, respectively. . In such an absorbent article, the facing sheet is joined to the backing sheet.

[0071] In another embodiment, the resorbable composite formed according to the present invention further comprises a fibrous layer. In this embodiment, the composite includes a reticulated core and a fibrous layer adjacent the outer facing surface of the core. This fiber layer is integrally formed with the reticulated core to form a single absorbent composite. As used herein, the term "formed together" refers to a composite having two or more layers manufactured in a forming process that results in the composite as a single structure. Generally, this layer is coextensive with the outer facing surface of the composite (ie, the upper and / or lower surfaces). Preferably, the composite includes first and second layers adjacent to each of the outer facing surfaces of the core (ie, these layers are coextensive with opposing surfaces of the core). An exemplary absorbent composite having a fibrous layer is shown in FIG. 21A, and an exemplary composite having multiple fibrous layers is shown in FIG. 21B. Referring to FIG. 21A, the absorbent composite 130 includes a reticulated core 10 and a layer 132, and as shown in FIG. 21B, the composite 140 includes a reticulated core 10, intermediate layers 132 and 134.
As described above, core 10 is a fiber matrix that includes fiber regions 12 that define voids 14, some of which include absorbent material 18.

In this embodiment, the present invention provides a unitary structure absorbent composite comprising two or more layers. The term "single" refers to a composite structure in which adjacent layers are connected together via a transition zone, resulting in a structure having adjacent layers in tight fluid communication. Referring to FIG. 21A, a surface layer 132 is integrally connected to the core layer 10 via a transition zone. Similarly, referring to FIG. 21B, layers 132 and 134 are each integrally connected to core layer 10 via a transition zone.

In this composite, the transition zone separates the layers of the composite. The nature of this transition zone can vary from composite to composite and from layer to layer within the composite. The transition zone can be designed to meet the performance requirements of a particular composite. Generally, the transition zone is integrally connected to adjacent layers and provides for tight fluid communication between the layers. The transition zone includes fibers that extend from one layer to an adjacent layer. For adjacent layers, the transition zone includes fibers extending from the first layer to the second layer and fibers extending from the second layer to the first layer.

[0074] The thickness of the transition zone within the composite can vary greatly depending on the composite. The absorbent composite of the present invention can include a relatively thin transition zone. Absorbent composites containing such a thin transition zone have a fairly sharp transition in material composition between the layers. Alternatively, the composite can include a transition zone where the transition from one zone to the next occurs over a relatively large thickness of the composite. In such an embodiment, the material composition of each zone is mixed to a significant degree resulting in a somewhat broader composition gradient.

A single composite having a plurality of layers and a method for forming them are described in International Patent Application PCT / US97 /
22342, Unitary Stratified Composite, and U.S. Patent Application Ser.No. 09 / 326,213,
Unitary Absorbent Systems, each of which is incorporated herein by reference in their entirety.

The layer (s) of the composite are fibrous and may be any suitable fiber or combination of the above fibers. The fiber composition of the layers can vary widely. This layer may be the same as or different from the fibers used to form the reticulated core. This layer can be formed from elastic fibers, matrix fibers, or a combination of elastic and matrix fibers. This layer may include a wet or dry strength agent. Suitable layers can be formed from a single fiber type, for example,
A layer comprising 100 percent wood pulp fibers (eg, pine spruce fibers). Alternatively, this layer can be formed from fiber blends, such as an 80:20 blend of wood pulp fibers and crosslinked fibers, as well as synthetic blends, and blends of synthetic and cellulosic fibers.

The composition having the desired characteristics can be obtained by changing the composition of the layer. For example, the layer preferably has a relatively high wood pulp fiber content to obtain a layer having a high liquid wicking capacity. Thus, for a liquid distribution, the layer preferably comprises wood pulp fibers, such as pine pine fibers. However, such layers have a relatively low content of wood pulp fibers and have a lower liquid acquisition rate compared to, for example, similarly structured layers that include a higher amount of crosslinked fibers. Conversely, to obtain a layer having a high liquid acquisition rate, the layer preferably has a relatively high crosslinked or synthetic fiber content. However, as a result of its high crosslinked fiber content, such a layer has a lower distribution of liquid than a comparable layer containing relatively few crosslinked fibers. For liquid acquisition, the layer may preferably include about 30 to about 50 weight percent crosslinked fibers and about 50 to about 70 weight percent pulp fibers. Alternatively, a layer having a high liquid acquisition rate may have a relatively high synthetic fiber content (eg, PET fibers or a blend of PET and thermally bonded fibers) in combination with cellulosic fibers. In some cases, it is possible for one or both layers to include synthetic fibers.

Since the layers of the composite are formed with a reticulated core to obtain an integrated unitary structure, the overall characteristics of the composite are optimized by appropriate selection of the individual core and layer components. can do. The properties of the first and second layers can be selectively and independently controlled and varied to further optimize the performance of the composite. The compositions of the first and second layers need not be the same. These layers can be formed from the same or different fiber furnishes. For compositions formed by the foam method, the basis weight of the layers can also be independently controlled and varied. The basis weight of the layers can also be varied relative to the basis weight of the core. In the foam method, the basis weight can be varied by adjusting the rate at which the fiber furnish is fed and deposited on the forming support. For example, varying the pump speed of a particular furnish effectively controls the basis weight of that portion of the composite. Thus, in one embodiment, the absorbent composite includes a reticulated core, intermediate first and second layers, each layer having a different basis weight. The basis weight of the layer can also be varied for the absorbent composite formed by the wet laid process.

This layer can be formed integrally with the mesh core by a wet laid and foam method. In general, a composite comprising a reticulated core and a layer can be formed by depositing a fiber slurry comprising the core and layer components substantially simultaneously. Deposition of the two or more fiber slurries on the forming support can be accomplished by standard equipment known in the art, including, for example, split and / or multislice headboxes.

Representative absorbent composites can be formed using conventional papermaking equipment, including, for example, a Rotoformer, Fourdrinier, and a twin-wire machine. Absorbent composites having a single layer can be formed by a Troformer and a Ford Linear device, and composites comprising two layers can be formed by a Twin Wire device. An exemplary method of forming an absorbent composite using a rotoformer device is shown in FIG. Performance characteristics of representative absorbent composites formed by this method are set forth in FIGS. 10-15. The absorbent composite formed using the rotoformer device includes a wire-side fiber layer. Layer thickness and overall composite structure can be controlled by the location of the headbox sparger that delivers the absorbent material and efficiently mixes the absorbent material with the fiber stock. Generally, the deeper the sparger introduces the absorbent material into the fiber stock on the rotoformer drum, the thinner the resulting layer. Conversely, by introducing the absorbent material into the fiber stock at a greater distance from the drum, a relatively thick layer can be formed.

The absorbent composite can be formed by devices and processes that include a twin-wire configuration (ie, a twin-forming wire). An exemplary twin wire device for forming a composite is shown in FIG. Referring to FIG. 22, device 200 includes twinning wires 202 and 204, on which the components of the composite are deposited. Basically, the fiber slurry 124 is introduced into the headbox 212 and deposited on the forming wires 202 and 204 at the headbox outlet. Vacuum elements 206 and 208 dewater the fiber slurry deposited on wires 202 and 204, respectively, to provide a partially dewatered web that is partially dewatered from the twin wire portion of the equipment. Is discharged as The web 126 continues to move along the wire 202 and further vacuum elements 210
To provide a wet composite 120, which is then dried by the drying means 21.
6 and dried to obtain the composite 10.

The absorbent material can be introduced into the fibrous web at any one of several locations in the twin wire process, depending on the desired product configuration. FIG.
Referring to, the absorbent material can be introduced to the partially dewatered web at locations 2, 3, or 4 or other locations along the wires 202 and 204 where the web is at least partially dewatered. . The absorbent material can be introduced into the partially dewatered web that has been formed and travels along the wires 202 and / or 204. The absorbent material can be injected into the partially dewatered fibrous web by nozzles laterally spaced across the width of the wire. These nozzles connect to a source of absorbent material. The nozzles can be located at various locations (eg, 2, 3, or 4 in FIG. 22) as described above. For example, FIG.
Referring to 2, the nozzle can be located at position 2 to inject the absorbent material into the partially dewatered web on wires 202 and 204.

[0083] Depending on the location at which the absorbent material is introduced, the twin wire method for forming the composite can result in a composite having a fibrous layer. The composite may include a fibrous layer coextensive with the outer surface of the composite. These fiber composites can be formed from a multilayer ramp former or a twin-wire former with a compartmentalized headbox. These methods can result in layered composites having layers that have uniquely designed properties and contain components to achieve composites with the desired properties.

For example, composite 130 having layer 132 and composite 140 having layers 132 and 134 can be formed by device 200. For composites where layers 132 and 134 contain the same components, a single fiber furnish 124 is introduced into headbox 212. To form a composite having layers 132 and 134 containing different components, headbox 212 may include one or more fibers for introducing fiber furnishes having different compositions (eg, 124a, 124b, and 124c). Including a baffle 214. In such a method, the upper and lower layers can be formed to include different components and have different basis weights and properties.

[0085] In one embodiment, the reticulated composite is formed by a foam forming method using the components described above. In the foam forming method, a fiber web having a plurality of layers and containing an absorbent material can be formed from a plurality of fiber slurries. The foam forming method can be performed on a twin wire forming machine.

This method can result in various multilayer composites, including, for example, composites having three layers. A typical composite having three layers is a first layer formed from fibers (eg, synthetic fibers, cellulosic fibers, and / or binder fibers); fibers and / or other absorbent materials, such as superabsorbents An intermediate layer formed from a conductive material; and a third layer formed from fibers. The method of the invention is versatile, such composites can have relatively different discrete layers, or, alternatively, can have a gradual transition zone from layer to layer.

A typical method for forming a fibrous web having an intermediate layer generally includes the following steps: (a) A first foam fiber slurry comprising fibers and a surfactant in an aqueous dispersion medium. Forming (b) forming a second foam fiber slurry comprising fibers and surfactant in an aqueous dispersion medium; (c) moving a first perforated element (eg, forming wire) in a first passage. (D) a step of moving the second perforated element in the second passage; (e) a step of passing the first foam slurry to contact the first perforated element moving in the first passage; ( f) passing the second foam slurry through contact with the second perforated element moving in the second passage; and (g) preventing the third material from contacting either the first or second perforated element. The first and second foam slurries Stroke passing between; (h) from the first and second foam slurries and third material, step for forming a fiber web by removing the foam and liquid from the slurry through the first and second perforated element.

As mentioned above, the method comprises a twin-wire forming machine, preferably a vertical forming machine,
More preferably, it is suitably implemented on a vertical downflow twin / wire former. In a vertical forming machine, the passage of the perforated element is substantially vertical.

A typical vertical downflow twin wire former useful in practicing the method of the present invention is shown in FIG. Referring to FIG. 23, the former includes a vertical headbox assembly having a former with a closed first end (top), closed first and second sides, and an interior volume. The second end (bottom) of the forming machine is defined by moving the first and second perforated elements, 202 and 204, and the forming nip 213. The interior volume defined by the closed first end, the closed first and second sides, and the first and second perforated elements of the forming machine is from the first end to the second end of the forming machine. An extending internal structure 230 is included. This internal structure defines a first volume 232 on one side thereof and a second volume 234 on the other side thereof. The forming machine further comprises a source 242 and a means 243 for introducing the first fiber / foam slurry into the first volume, a source 24 for introducing the second fiber / foam slurry into the second volume.
4 and means 245, and a source 246 and means 247 for introducing the third material into the internal structure. Means for removing foam from the first and second slurries through the perforated elements (eg, suction boxes 206 and 208) are also included in the headbox assembly.

In this method, the twin wire former includes means for introducing at least a third material through the internal structure. In general, the internal structure of the forming machine (ie, structure 230 in FIG. 23) is arranged such that the material introduced through the internal structure does not directly contact the first and second perforated elements. You. Thus, material is introduced between the first and second slurries through the internal structure after the slurries have come into contact with the perforated elements and removal of foam and liquid from those slurries has begun. Such an arrangement is particularly useful for introducing superabsorbent materials and for forming a layered structure in which the third material is a slurry containing superabsorbent materials. Depending on the nature of the composite to be formed, the first and second fiber / foam slurries may be the same or different from each other and the third material.

A means for removing foam from the first and second slurries through the perforated element to form a web on the perforated element is also included in the headbox assembly. The means for removing the foam may include any conventional means for that purpose, such as suction rollers, press rollers, or other conventional structures. In a preferred embodiment, first and second suction box assemblies are provided, located on the opposite side of the internal structure from the perforated elements (see boxes 206 and 208 in FIGS. 22 and 23).

The flexibility and flexibility of the composite are factors that determine its suitability for incorporation of the composite into a personal care absorbent product. The flexibility of the composite can be indicated by the composite end ring crush, which is a measure of the force required to compress the composite as described below. For composites that are to be incorporated into personal care absorbent products, suitable ring crush values range from about 400 to about 1600 grams / inch. The flexibility of the composite can be indicated by various parameters, including the end compression of the composite. Edge compression (EC) is the force required to compress the composite, corrected by the composite's basis weight as described below. For composites that are to be suitably incorporated into personal care absorbent products, the composite has a ring crush value in the range of about 400-1600 g and a basis weight in the range of about 300 to about 600 gsm.

[0093] These composites achieve the desired flexibility and flexibility by adjusting the composition of the composite. The flexibility and flexibility of the composite can be adjusted, controlled, and optimized by adjusting the amounts and ratios of the components of the composite. These composites comprise three basic components: (1) an absorbent material; (2) a cross-linked cellulose fiber; and (3).
Contains matrix fibers. Generally, increasing the amount and / or proportion of absorbent material (eg, superabsorbent material) and / or cross-linked fibers in the composite increases the flexibility and flexibility of the composite. Conversely, increasing the amount of matrix fibers (eg, pulp fibers) in the composite generally reduces flexibility and flexibility.

[0094] Representative composites of the present invention having suitable flexibility and flexibility include about 30 to about 80 weight percent absorbent material, about 10 to about 50 weight percent cross-linked fibers, and about 5 to about 50 weight percent. Contains 30 weight percent matrix fibers.

In one embodiment, the composite comprises from about 40 to about 70 percent, preferably about 60 weight percent, of the superabsorbent material, based on the total weight of the composite;
To about 50 percent, preferably about 30 percent by weight of crosslinked fiber; and about 5 to about 20 percent, preferably about 10 percent, based on the total weight of the composite.
Contains weight percent matrix fibers. For composites containing less than about 50 weight percent superabsorbent material, the ratio of crosslinked fibers to matrix fibers can be at least 1: 1 and preferably about 2: 1.

[0096] In another embodiment, the composite comprises about 70 weight percent superabsorbent material and about 30 weight percent fiber. In one embodiment, the fibers comprise a blend of matrix fibers (eg, Pinus densiflora) and crosslinked fibers having a crosslinked fiber: matrix fiber ratio of at least 1: 1, preferably at least about 2: 1.

[0097] In a more preferred embodiment, the conjugate is from about 0.50 mm to about 1.0 mm.
superabsorbent polymer particles having an average particle size in the range of mm. Examples 17-19 describe the composition and flexibility and flexibility of a representative absorbent composite formed in accordance with the present invention. The composite described in Example 17 was formed as a handsheet, and the composite described in Example 18 was formed on a twin-wire former by a foam forming method. The effect of superabsorbent polymer particle size on the flexibility and flexibility of the composite is described in Example 20.

[0098] In addition to having flexibility and flexibility suitable for incorporation into personal care absorbent products, the composites of the present invention exhibit advantageous structural integrity. The structural integrity of the composite can be indicated by its tensile strength. Composites suitable for use in personal care absorbent products have a wet tensile strength of at least about 50 g / in. For mechanical processing, suitable composites have a dry tensile strength of at least about 450 g / in.

Generally, as the tensile strength increases, the ring crush of the composite increases. The correlation between the edge ring crush of the composite and the drying tension is graphically shown in FIG. 30, which shows that the edge ring crush increases dramatically with increasing drying tension. While there appears to be no correlation between composite basis weight and drying tension, there is some correlation between composite density and drying tension.

The tensile strength and creep of representative composites of the present invention are shown in Example 21. The composites of the present invention exhibit advantageous fluid properties. This property can be indicated by various measures including liquid acquisition rate, wicking, and rewet. Typical complex acquisition rate and rewet, uncontrolled vertical wicking height, and saddle acquisition rate (saddle acq
The uisition rate, distribution, and siphon height are described in Example 22.

The absorbent composite formed according to the present invention can be incorporated into an absorbent article such as a diaper as an absorbent core or storage layer. The conjugate can be used alone or in combination with one or more other layers, such as an acquisition and / or distribution layer, to provide a useful absorbent construct.

A representative absorbent construct incorporating an absorbent composite having a reticulated core and a fiber layer is shown in FIGS. 24 and 25. Referring to FIG. 24A, construct 150 includes composite 130 (ie, reticulated core 10 and layer 132) used as a storage layer in combination with upper acquisition layer 20. FIG. 24B shows a construct 160, which includes the composite 130 and the acquisition layer 20 with a layer 132 adjacent to the acquisition layer 20. The construct 170 including the acquisition layer 20 and the composite 140 is shown in FIG. 24C.

In addition to the above constructs comprising a combination of an absorbent composite and an acquisition layer, additional constructs can include a distribution layer intermediate the acquisition layer and the composite. FIG.
Shown is a construct 180 having an intermediate layer 30 (eg, a distribution layer) located between the acquisition layer 20 and the composite 130. Similarly, FIGS. 25B and 25C respectively show acquisition layer 2
Constructs 190 and 2 with layer 30 intermediate 0 and composites 130 and 140
00 is shown.

Complexes 130 and 140 and constructs 150, 160, 170, 180, 19
0 and 200 can be incorporated into the absorbent article. In general, each figure 2
Absorbent articles 210, 220, and 230 shown in FIGS. 6A-26C; FIG.
The absorbent articles 240, 250, and 260 shown in FIGS. 7A-27C; and the absorbent articles 270, 280, and 290 shown in FIGS. 24, and
Complexes 130, 140 and constructs 150, 160, 170, 180, respectively
, 190, and 200. In such an absorbent article, the facing sheet is bonded to the backing sheet.

The following examples are given by way of illustration and not limitation.

EXAMPLES Example 1 Formation of Reticulated Absorbent Composite: Representative Wet Raid Method This example describes a wet laid method for forming a representative absorbent composite.

The wet laid composite formed according to the present invention is prepared using standard wet laid equipment known to those skilled in the art. A slurry of a mixture of standard wood pulp fibers and crosslinked pulp fibers in water (48 and 12 weight percent, respectively, based on the total weight of the dry composite) having a consistency of about 0.25 to 3 percent is formed. Consistency is defined as the weight percent of fibers present in the slurry, based on the total weight of the slurry. Next, a wet strength agent (0.5 percent based on total composite weight), such as Kymene®, is added to the fiber mixture. Finally, an absorbent material (40 weight percent based on the total weight of the dry composite) is added to the slurry and the slurry is mixed thoroughly and then spread on a wire mesh to form a wet composite. The wet composite is dried to a moisture content of about 9 to about 15 weight percent based on the total composite weight to form a typical reticulated absorbent composite.

From the composite formed as described above, absorbent composites having various basis weights can be prepared by pre-drying or post-drying densification methods known to those skilled in the art.

Example 2 Formation of Reticulated Absorbent Composite: Representative Foam Method This example describes a foam method for forming a representative absorbent composite.

Add 4 L of water and pulp fiber to a lab size Waring blender. This mixture is blended for a short time. Next, the crosslinked cellulose fibers are added to the pulp fibers and blended for at least one minute to open the crosslinked fibers and achieve a mixture of the two types of fibers. The resulting mixture may contain 0.07 to 12 weight percent solids.

The mixture is placed in a container and blended for several seconds with an air-entrapping blade. Add the surfactant (Incronan 30, Croda, Inc.) to the blended mixture.
Add about 1 g of active surfactant solids per gram of fiber. The mixture is compounded while gradually increasing the height of the mixer blade from the rising foam.
After about 1 minute, the mixing is finished and the superabsorbent is added, and mixing is resumed for another 1.5 minutes at a constant mixer blade height. The resulting foam-fiber mixture has about three times the volume of the original mixture.

The mixture is rapidly poured into a sheet mold having a tilted diffusion plate. After adding the mixture, the plate is removed from the mold and a strong vacuum is applied to reduce the foam-fiber height. After most of the visible foam has disappeared, the vacuum is shut off and the resulting sheet is removed from the mold and sent over a slit couch along a forming wire to remove excess foam and water.

Next, the sheet is dried in a drying oven to remove moisture.

Example 3 Acquisition time of a representative resorbable complex In this example, the acquisition time of a representative resorbable complex (composite A) formed according to the present invention was determined using a commercially available diaper (diaper A). , Kimberly-Clark).

The test was performed in a commercial diaper (Kimberly-Clark) from which the core and surge management layer were removed and the surroundings were used. Test diapers were prepared by inserting the absorbent complex into the diaper.

The aqueous solution used in this test was manufactured by National Scientific under the trade name RICC.
A is a synthetic urea available in A. This synthetic urea has 135 meq. On a weight basis (based on total weight). / L sodium, 8.6 meq. / L calcium, 7
. 7meq. / L A physiological saline solution containing magnesium and 1.94% urea, in addition to other components.

A sample of the absorbent structure was prepared by determining the center of the core of the structure, measuring 1 inch forward for the liquid application location, and marking the location with an “X”. Once the sample has been prepared, first place the sample on a plastic base (43/4 inch x 19).
(1/4 inch), then the funnel capture plate (4 inch x 4 inch plastic plate) was placed on top of the sample with the holes in the plate aligned with the top of the "x". Next, a donut-shaped weight (1400 g) was placed on the top of the funnel capturing plate, and a funnel (4 inches in diameter) was attached. After that, 100m
Liquid acquisition was determined by pouring L synthetic urea into the funnel and measuring the time from when the liquid was first introduced into the funnel until the liquid entered the sample and disappeared from the bottom of the funnel. The measured time is the acquisition time of the first liquid sweep. After waiting one minute, a second 100 mL was added to the funnel and the acquisition time of the second push was measured. After further waiting for one minute, the third acquisition was repeated to obtain a third acquisition time. Three consecutive 100s for diaper A and complex A
Acquisition times, reported in seconds, for each of the mL liquid sweeps are summarized in Table 1.

Table 1 Comparison of acquisition time

[0119]

[Table 1]

As shown in Table 1, liquids are more quickly obtained by the absorbent complex than commercial diapers with air-laid storage cores. These results indicate that the air laid core does not acquire liquid as quickly as almost the reticulated composite. Also, commercially available diapers exhibited a characteristic reduction in acquisition speed with respect to a continuous swirling of liquid. In contrast, the complexes formed in accordance with the present invention maintained a relatively constant acquisition time, as they continued to absorb liquid for successive rushes. Importantly, the absorbent composite exhibits substantially less (approximately four times) the acquisition time of the third rush of the commercial diaper than the first rush. These results generally reflect the higher wicking capacity of the wet laid composite and the capillary network compared to a conventional air laid storage core, and in particular reflect the enhanced performance of the mesh absorbent composite.

Example 4 Acquisition time and re-wetting of a representative resorbable complex In this example, the acquisition time of a representative resorbable complex formed according to the present invention (designated composites A1-A4) Re-wet with commercially available diapers (Diaper A, Kimber
ly-Clark). Complexes A1-A4 differ depending on how the complexes were dried.

The specific properties of the tested composites, including the amount of superabsorbent material in the composite (weight percent SAP) and the basis weight of each composite are summarized in Table 2. The test was performed with a commercial diaper (Kimberly-Clark), from which the core was removed and the surroundings were used. Test diapers were prepared by inserting test complexes into these diapers.

Acquisition time and rewet were determined using the multiple-dose test described below.
rewet test). Briefly, this multi-dose rewet test involves the amount of synthetic urea released from the absorbent structure after each of the three liquid applications, and the amount of urea required to wick into the product for each of the three liquid inputs. Measure time.

The aqueous solution used in these tests was synthetic urea available from National Scientific under the name RICCA and was as described in Example 1 above.

A pre-weighed sample of the absorbent structure was prepared for testing by determining the center of the core of the structure, measuring 1 inch forward for the liquid application position and marking that position with a "x". A liquid application funnel (minimum 100 mL capacity, flow rate 5-7 mL / s) was placed 4 inches above the sample surface at the "x" position. When the sample was prepared, the test was performed as follows. The sample was flattened nonwoven side up under the liquid application funnel on a table top. The funnel was charged with one charge (100 mL) of synthetic urea.
Dosing ring (5/32 inch stainless steel, 2 inch ID x 3)
Inch high) was placed on the "x" marked on the sample. A first charge of synthetic urea was applied in the charge ring. Using a stopwatch, the liquid acquisition time was recorded in seconds from when the funnel valve was opened until the liquid was pumped into the product from the bottom of the dosing ring. After a waiting period of 20 minutes, rewet was determined. During a waiting period of 20 minutes after applying the first charge, a bundle of filter paper (19-22 g, Whatman # 3, 11.0 cm or equivalent, exposed to room humidity for a minimum of 2 hours prior to testing) was weighed. This pre-weighed bundle of filter paper was centered in the wet area. Cylindrical weight (8.9cm in diameter,
9.8 Ib. ) Was placed on top of these filter papers. After 2 minutes, remove the weight,
The filter paper was weighed and the change in weight was recorded. This procedure was repeated two more times. A second charge of synthetic urea was added to the diaper to determine the acquisition time, and the filter paper was placed on the sample for 2 minutes to determine the change in weight. For the second charge, the weight of the dried filter paper is 29-32 g
For the third charge, the weight of the filter paper was 39-42 g. The dried paper before feeding was supplemented with further dried filter paper.

Liquid acquisition time is reported as the length of time (in seconds) required for liquid to be absorbed into the product for each of the three doses. These results are summarized in Table 2.

Rewetting is the amount of liquid (grams) absorbed and returned to the filter paper after each liquid charge (
That is, the difference between the weight of the wet filter paper and the weight of the dry filter paper is reported. These results are also summarized in Table 2.

Table 2 Comparison of acquisition time and rewet

[0129]

[Table 2]

As shown in Table 2, a representative conjugate formed according to the present invention (Complex A1
The acquisition time of -A4) was significantly shorter than the commercial core. Rewetting of a representative complex (complexes A1-A4) was significantly less than the other cores. These composites initially showed relatively little rewet, but after a third rush, the commercial core showed significant rewet. In contrast, Complex A continued to show less rewet.

Example 5 Horizontal and vertical wicking of a typical resorbable composite In this example, the wicking properties of a typical resorbable composite (Complex A) were measured using a commercially available diaper storage core (Diaper B). , Procter & Gamble).

The horizontal wicking test measures the time required for a liquid to travel horizontally a preselected distance. The test is performed by placing the sample complex on a horizontal surface at one end in contact with a liquid bath and measuring the time required for the liquid to travel a preselected distance. Briefly, sample composite strips (40 cm x 10 cm) were cut from pulp sheets or other sources. If the sheet has a flow direction, 4
Make a cut so that the length of 0 cm is parallel to the flow direction. 10cm of strip
Starting at one end of the width, the first line was marked 4.5 cm from the edge of the strip, and then successive lines at 5 cm intervals were marked along the entire length of the strip (ie,
0 cm, 5 cm, 10 cm, 15 cm, 20 cm, 25 cm, 30 cm, and 3
5 cm). A horizontal siphon was provided having a central trough with a horizontal wing, the wing extending away from the opposite side of the trough. The unsupported end of each wing was positioned flush with the inner end of the trough. A plastic extension was placed at the end of each wing to support each wing in a horizontal position. Thereafter, the trough was filled with synthetic urea. Next, 4.5 c of the sample composite strip was
The bend was gradually bent at the mark position of m to form an angle of about 45 ° in the strip. Then
The strip was placed on the wing such that the strip lay down horizontally and the bent end of the strip extended into the trough to contact the liquid. The wicking of the liquid is marked on the complex,
The time was measured starting from when the liquid reached the first line of 5 cm from the 4.5 cm bend. Thereafter, the siphoning time was recorded at intervals of 5 cm when reaching the section (for example, 5 cm, 10 cm) marked by 50% of the liquid front end. The level of liquid in the trough was maintained at a relatively constant level throughout the test by supplementing with additional synthetic urea. Table 3 summarizes the results of the horizontal siphoning.

Table 3 Comparison of horizontal siphoning

[0134]

[Table 3]

The results tabulated above show that the absorbent composite formed according to the present invention has enhanced horizontal wicking as compared to a conventional air laid core. The wicking time of Complex A is about 50% of conventional diaper core. Thus, the horizontal wicking of Complex A is about 1.3 to about 3 times that of the commercial storage core.

The vertical wicking test measures the time required for a liquid to travel vertically a preselected distance. The test was performed by suspending the sample complex vertically with one end of the complex in contact with a liquid bath and measuring the time required for the liquid to travel a preselected distance. Prior to testing, a sample composite (10 cm x 22 cm) was cut and 1 cm, 11 cm, 16 cm, and 21 cm from one of the ends of the strip.
Was marked with a continuous line. Preferably, the sample is 50 percent relative humidity,
After preconditioning at 23 ° C. for 12 hours, they were stored in sample bags until testing. The sample complex was clamped at the 1 cm mark at its top end with its length oriented vertically, and its bottom end was contacted with a bath containing synthetic urea. Timing was started as soon as the strip was in contact with the liquid. After that, 5% of the suction tip is 5cm, 10c
The time required to reach m, 15 cm and 20 cm was recorded. The results of these vertical wickings are summarized in Table 4.

Table 4 Comparison of vertical suction

[0138]

[Table 4]

Similar to the horizontal wicking results, Composite A had significantly greater vertical wicking compared to the commercial core. These results also show that the composite formed according to the present invention has significantly higher wet tensile strength compared to conventional air-laid composites.

Example 6 Liquid Distribution of Representative Reticulated Absorbent Composite In this example, the distribution of liquid in the reticulated absorbent composite (composite A) was determined by comparing two types of commercially available diapers (diapers A and B described above). Compare with This test measures the ability of the diaper core to dispense the acquired liquid. A preferred distribution has a deviation from the mean of 0%. An ideal liquid distribution results in an equal distribution of the applied liquid in each of the four distribution zones (ie, about 25% liquid in each zone).

The distribution of the liquid is determined by weighing different zones of the sample that have already been subjected to the multi-dose rewetting test described in Example 4 above. Basically, after the last rewet, the diaper wing is removed and then cut into four equal length distribution zones. Thereafter, each zone is weighed to determine the weight of liquid contained in each zone.

The results of the liquid distribution of a typical reticulated absorbent composite are near ideal. These results
While a typical commercial storage core accumulates liquid near the squeezing site, it shows that liquid is efficiently and effectively distributed throughout the reticulated absorbent core.

Example 7 Wet and Dry Tensile Strength of Reticulated Absorbent Composite In this example, the measurement of the wet and dry tensile strength of a representative absorbent composite is described. Wet tensile strength was determined using 2.5 × 4 inch strips wetted with 10: 1 weight ratio saline: sample using 0.9% saline as described below. To decide. Dry tensile strength is performed as described by TAPPI Method T 494 om-96-T.

The dry pad tension integrity test is performed on a 4 inch by 4 inch square test pad by clamping the dry test pad on two opposing sides.
A pad approximately 3 inches long is visible between the clamps. The sample is pulled vertically in an Instron tester and the measured tensile strength is reported in N / m. Tensile strength is determined by dividing the tensile strength by the basis weight g / m ² to give a tensile index (tensile index).
index) Convert to Nm / g.

The wet tension integrity test is carried out by immersing the sample complex in synthetic urea for 10 minutes and then draining it for 5 minutes, collecting the sample complex, and placing the sample in a horizontal jig. After clamping the opposite ends of the sample, pull horizontally with an Instron tester. Wet tensile strength N
/ M is the tensile index Nm / by dividing its tensile strength by the basis weight g / m ^2.
Convert to g.

Typically, by increasing the amount of Kymene® from 2 pounds to 100 pounds per ton of fiber, the dry tensile strength is from about 0.15 Nm / g to 0.66 Nm
/ G, the wet tensile strength increases from about 1.5 Nm / g to about 2.4 Nm / g.

Wet tension is determined by the following procedure: Sample 6.35 cm (2.5 in.) CD x 10.2 cm (4 in.) MD ^* Equipment: Horizontal Instron 10 Newton Load Cell Clamp pressure 20 psi, sample integrity Minimize loss 60 mL syringe 0.9% Blood Bank Saline Solution Procedure 1) Weigh the sample to the nearest 0.1 gram. 2) Using a syringe, add Saline Solution 10 times the sample weight evenly to the top of the sample. 3) The transport of the solution is controlled so that the sample is not damaged. 4) When all the solution has been transported, start the timer for 5 minutes. 5) After 5 minutes, clamp the sample in the Instron and test the tension. 6) Repeat three times for each sample type. 7) Record the average value in b / in. ^* Note: The sample size may be less than 10.2 cm as long as the sample is held firmly by the end clamp.

Example 8 Taber Stiffness of a Representative Reticulated Absorbent Composite The stiffness of a reticulated absorbent composite formed in accordance with the present invention was determined by the Taber stiffness method. Representative composites were formed by wet laid and foam methods. These composites comprise matrix fibers (48 weight percent, Pinus pine commercially available from Weyerhaeuser Co. under the name NB416), elastic fibers (12 weight percent, polymaleic acid cross-linked fibers), and absorbent materials (40 weight percent). (A superabsorbent material commercially available from Stockhausen). One of the wet laid composites and one of the foam forming composites comprise a wet strength agent (about 0.5 weight percent, polyamide-commercially available from Hercules under the name Kymene®). Epichlorohydrin resin).

The stiffness of the foam forming composite was significantly lower than a similarly configured wet laid composite. These results also show that for wet laid composites, the inclusion of a wet strength agent increases the stiffness of the composite.

Example 9 Formation of Reticulated Absorbent Composite: Representative Wet Raid Method This example describes a representative wet laid method for forming a reticulated composite using a rotoformer paper machine.

Briefly, a slurry of absorbent material and fibers in water was introduced into the rotoformer headbox. The fiber slurry was introduced into the headbox in the usual way. The absorbent slurry was introduced by using a dispersion unit consisting of a set of spargers. The sparger was supplied by a header, which was supplied by an absorbent slurry source. The dispersion unit is attached to the rotoformer by inserting a sparger into the headbox fiber stock so that the flow of the absorbent slurry is opposite the fiber stock stream. It is believed that such backflow of the absorbent slurry results in more effective mixing of the absorbent material and fibers than would occur with the absorbent material flow in the same direction as the fiber stock.

The absorbent material is introduced into the rotoformer headbox as a slurry in water. One of the methods that provides suitable results for introducing the absorbent material into the headbox
One is a mixing system that includes a funnel attached directly to the inlet of the pump, the pump being supplied with chilled water at a controlled rate. The funnel receives dry absorbent material conveyed from the absorbent material source by water and auger weighing to form a water reservoir containing the absorbent material and water. The absorbent slurry is preferably pumped from the funnel to the headbox at about the same rate as the water is conveyed to the funnel. Such a system minimizes exposure of the absorbent to water. In practice, the absorbent slurry is conveyed from the mixing system to the headbox within less than about 10 seconds via a 10 to 50 foot conduit.

In a typical forming operation, the fiber stock stream to the rotoformer headbox was about 90 gpm (gal / min) and the absorbent slurry (1-2.6% solids) stream was about 10 gpm. Was. Prior to starting the fiber stock flow into the headbox and introducing the absorbent slurry into the dispersion unit, water was flowed from the dispersion unit to the headbox to prevent fibers from plugging the sparger. When the target basis weight of the fibers was reached, the absorbent auger weighing system was started and the absorbent slurry was introduced into the headbox. For operations performed according to the method described above,
The target fiber basis weight is about 370 gsm (g / m ² ), and the production rate is about 10 fp.
m (fl / min). This relatively slow production rate is the result of the relatively limited drying capacity of the flatbed dryer of this machine.

Depositing the contents of the headbox, including the fibers and the absorbent, on the forming wire;
Dehydration gave a wet complex. The wet composite was then dried to a moisture content of about 9 to about 15 weight percent based on the total composite weight to form a typical resorbable composite.

Absorbent composites having various basis weights were prepared from composites formed as described above.
It can be prepared by a densification method before or after drying known to those skilled in the art. Examples 10-15 illustrate the formation of a representative reticulated absorbent composite using the methods described above.

Example 10 A representative composite was formed as described in Example 9. The composite is
It contained about 60% by weight fiber and about 40% by weight absorbent material based on the total weight of the composite. The fiber raw material is 80% by weight of standard wood pulp fiber (FR41).
Once dried southern pine (available from Warehauser under the name 6)
a mixture of southern pines and 20% by weight of crosslinked pulp fibers. The absorbent material was a crosslinked polyacrylate commercially available from Stockhausen under the name SXM77. The polyacrylate was screened using a 300 micron mesh to remove fines prior to use.
The composite also contained about 25 pounds per ton of fiber of a wet strength agent (a polyacrylamide-epichlorohydrin resin commercially available from Hercules under the name Kimen® 557LX).

The target density of the composite was performed by calendering using a single nip without applying load. Characterization data for a representative composite formed as described above (Compound B
) Are shown in Tables 5 and 6 in Example 16.

Example 11 A representative composite was formed as described in Example 10 except that the composite was calendered at 25 fpm.

Characteristic data for a representative composite formed as described above (Compound C
) Are shown in Tables 5 and 6 in Example 16.

Example 12 A representative composite has a wet strength agent content of 12.1 per ton of fiber in the composite.
FR416 reduced to 5 pounds and its standard wood pulp fiber is not dried
Formed as described in Example 11 except that it was a fiber.

[0161] Characterization data for a representative composite formed as described above (Compound D
) Are shown in Tables 5 and 6 in Example 16.

Example 13 A representative composite was prepared as in Example 12 except that the composite was not densified.
Formed as described in.

[0163] Characterization data for a representative composite formed as described above (Compound E
) Are shown in Tables 5 and 6 in Example 16.

Example 14 A representative composite was formed as described in Example 12 except that the wood pulp fiber was once dried FR416 fiber.

Characteristic data for a representative composite formed as described above (Compound F
) Are shown in Tables 5 and 6 in Example 16.

Example 15 A representative composite was prepared by increasing the amount of fiber in the composite to about 80% by weight, based on the total weight of the composite, and the absorbent present in the composite. About 2
Formed as described in Example 12, except reduced to 0%.

Characteristic data for a representative composite formed as described above (Compound G
) Are shown in Tables 5 and 6 in Example 16.

Example 16 A representative composite (Compound BD) prepared as described in Examples 10-15
) Are summarized in Tables 5 and 6. The liquid wicking action, absorbent capacity, wet and dry tensile strength and wet strength of that representative composite are compared in Table 5 to a conventional handsheet. The conventional handsheet has a basis weight and density relative to the representative composite, and 60% by weight of fiber per ton of fiber (25% by weight of crosslinked representative fiber and 75% by weight). % Of standard wood pulp fiber), 40% by weight of superabsorbent material, and 12.5 pounds of chimen per ton of fiber. The results shown in Table 5 are the average of three measurements, except for the tensile strength, which is the average of four measurements. In the table, "MD
"Is the composite machine direction and" CD] is the cross-machine direction. The wicking value is obtained in the manner described in Example 5, and the wet and dry tensile values are
Obtained by the method described in Example 7. The wet strength value is a calculated value and is defined as the ratio of wet tension to dry tension. Mass flow rate (mass fl
ow rate (g / min / g) indicates the increase in weight of the composite by 15 c
m was determined by dividing by the time required to wick or the lesser of 15 minutes and dividing by the weight of the initial sample.

[0169]

[Table 5]

The absorbent capacity of some of the representative composites is summarized in Table 6. In this volume test, the representative composite was immersed in 1% saline. The sample was allowed to absorb and swell the liquid for 10 minutes. The difference in weight of the composite before and after swelling for 10 minutes is its volume, reported as cc / g.

[0171]

[Table 6]

Example 17 Flexibility and Softness of an Exemplary Reticulated Absorbent Composite Wetlaid Handsheet The flexibility and softness of an exemplary reticulated absorbent composite formed in accordance with the present invention. Softness is determined by the edge crushing method along the edge.
method). In that method, a piece of the composite (typically about 12 inches long) is formed in a cylinder, and the ends are formed with the width of the composite (typically about 2.5 inches). Stapled together to provide a cylinder having a height equal to inches). Ring fracture along the edge is measured by adding mass to the top of the composite link sufficient to reduce the composite cylinder height by a factor of two. In that measurement, the more flexible the composite, the less weight is required to reduce its height. Ring fracture along the edge is measured and reported as its mass. Compression along the edge (EC) is the ring fracture reported in g / gsm in the table below.

The following is a description of ring crushing. Sample 6.35 cm (2.5 inches) x 30.5 cm (12 inches) 3 analyzes (A, B, C)

Method (1) Sample size composite sample 3 to length in machine direction (MD)
Cutting into two pieces (2) Conditioning the sample for 2 hours at 50% relative humidity and room temperature (3) On the wire side on the outside, without overlap, in the loop so that the two narrow ends meet To form the individual samples. Four staples are used to secure the ends together at the top, bottom and middle. The top and bottom staples should be 0.3-0.5 cm from the end, and the middle staples should be less than 2 cm from each other. Finally, ensure that each staple penetrates only the fiber area. (4) Set the bottom platen on a smooth level surface. (5) Place the sample in the center between the end and the top and bottom platens. (6) Gently place the 100 g weight (or 500 weight) on the center of the top platen and wait 3 seconds. (7) Then gently stack the 100 g weight three more times at 3 second intervals. (8) If the ring collapses within 50% of its initial height within a three second interval, then record the total weight required to do so, ie, the weight of the top platen and the other Add weight. (9) If the total weight does not disintegrate the sample, then carefully remove the four 100 g weights. (10) Gently add another 500 g weight and wait 3 seconds. (11) If the ring collapses at 50% or more of its initial height within a 3 second interval, then record the total weight required to do so, ie, the weight of the top platen and the weight ( Singular or plural). (12) The steps (6) to (11) are repeated to increase the weight by 500 g once in each step. (13) The steps (5) to (11) are repeated for another copy test. (14) Record the average weight of the duplicate test with g · f rounded to the nearest 10 g.

Formula: Average ring crush weight = (weight A + weight B + weight C) / 3 A representative composite was formed by the wetlaid and foam method. A representative composite was molded as a handsheet using a 20 inch x 20 inch handsheet matrix. The target ream weight of the composite was 400 g / m ² . Five blotters and a vacuum paper machine were used to increase the consistency after molding to about 20-35%. Ice water was used as the dispersion medium to reduce the swelling of the absorbent material. The composite was dried at 150 ° C. Unless otherwise noted, each composite had a wet strength agent (polyamide-epichlorohydrin resin commercially available from Hercules under the name Kymene: 10 lb / ton). Fibers) and absorbent material (superabsorbent material from Stockhausen, 40% by weight based on the total weight of the composite). The composite is made up of varying amounts of matrix fibers (Wayerha
south pine (southe pine) commercially available from user Co. under the name NB416
rn pine)), resin fibers (cross-linked fibers), synthetic fibers, and other materials as indicated.

A typical composite composition evaluated for flexibility by edgewise ring crush is as follows: Control composite: a wetlaid composite composed of 40% by weight of superabsorbent material and 60% by weight of matrix fibers.

Composite 1: 40% by weight of superabsorbent material, 30% by weight of matrix fibers and crosslinked fibers 3
A foam molded composite composed of 0% by weight. Composite 2: 40% by weight of superabsorbent material, 30% by weight of matrix fiber and crosslinked fiber 3
Wet complex composed of 0% by weight.

Composite 3: 40% by weight of superabsorbent material, 15% by weight of matrix fibers and crosslinked fibers 4
Wet complex composed of 5% by weight. Composite 4: 40% by weight of superabsorbent material, 30% by weight of matrix fiber, chemical thermal power (c
hemithermomechanical) pulp (CTMP) 30% by weight (Svenska Cellulosa Aktiebola
get, Sweden).

Composite 5: A wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers, 30% by weight of high porosity fibers (HPZ) (Buckeye Corp., Memphis, TN). Composite 6: a wet composite composed of 60% by weight of superabsorbent material and 40% by weight of matrix fibers.

Composite 7: 60% by weight of superabsorbent material, 20% by weight of matrix fiber and crosslinked fiber 2
Wet complex composed of 0% by weight. Composite 8-1: Superabsorbent material (large screened SXM-77, 0.05-1.0
0 mm, SXM-77) available from Stockhausen, a wet composite consisting of 40% by weight of matrix fibers and 30% by weight of crosslinked fibers.

Complex 8-2: Superabsorbent material (small screened SXM-77, 0.208-
0.355) A wet composite composed of 40% by weight, 30% by weight of matrix fibers and 30% by weight of crosslinked fibers.

Composite 8-3: Superabsorbent material (unsorted SXM-77) 40% by weight, matrix fiber 30
A wet composite composed of 30% by weight and 30% by weight crosslinked fibers. Composite 8-4: Superabsorbent material (well-selected superabsorbent, 0.50-1.00mm) 40% by weight
, A wet composite composed of 30% by weight of matrix fibers and 30% by weight of crosslinked fibers.

Composite 9: Wet composite composed of 40% by weight of superabsorbent material, 60% by weight of matrix fiber (NB416) coated with clay (25% by weight, manufactured by Wayerhauser, trade name T-757) .

Composite 10: a wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers (T-757) and 30% by weight of crosslinked fibers. Composite 11: from 30% by weight of superabsorbent material, 30% by weight of crosslinked fibers, and 30% by weight of matrix fibers (MB416) coated with precipitated calcium carbonate (10% by weight, manufactured by Wayerhauser, trade name MT-10). The wet complex composed.

Composite 12: 40% by weight of superabsorbent material, 30% by weight of matrix fibers and synthetic fibers
(PET fiber, straight fiber T-224) (Hoechst Celanese Corp., Charlotte, NC) 30% by weight
A wet complex composed of

Composite 13: 40% by weight of superabsorbent material, 30% by weight of matrix fibers and synthetic fibers
(PET fiber, crimped T-224) A wet composite composed of 30% by weight. Composite 14: a wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers and 30% by weight of cellulose acetate.

Composite 15: a wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers and 30% by weight of crosslinked fibers. Surfactant RW-150 (Unio
n Carbide Corporation).

Composite 16: a wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers and 30% by weight of crosslinked fibers. Surfactant QS-15 (Union
Carbide Corporation).

Composite 17: A wet composite composed of 40% by weight of superabsorbent material and 60% by weight of matrix fibers. During the forming process, a debonding agent, Quaker 224C (Qua
ker Chemical Corp., Conshohken, PA).

Composite 18: a wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers and 30% by weight of crosslinked fibers. Debonding age (debonding age)
nt) Quaker 224C included.

Composite 19: A wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers and 30% by weight of crosslinked fibers. The composite is obtained by partially drying the web to about 70% consistency, moving the web through an S-shaped configuration around two narrow diameter (1 inch) rolls, and then drying it completely. Formed.

Composite 20: a wet composite composed of 40% by weight of superabsorbent material, 30% by weight of matrix fibers and 30% by weight of crosslinked fibers. After treating the complex with ethanol,
Drying replaced the water in the composite.

Table 7 summarizes the composition of representative conjugates.

[0194]

[Table 7]

Table 8 shows the ring crush values (g) and the edge compression values (g / gsm) of the representative composites. Table 8
Indicates the average of three measurements. Ring crushing value is 30.5cm × 6.35cm
Of the composite sheet.

[0196]

[Table 8]

The results show that the flexibility and pliability of the composite as measured by edgewise ring crush and layer compression are the components of the composite and their amounts. And that it can be adjusted and controlled by optimizing. In general, increasing the percentage of matrix fibers in a composite reduces its flexibility, and conversely, crosslinked fibers in the composite.
Increasing the percentage of either r) or the superabsorbent material results in higher flexibility.

The presence of cross-linked fibers in a composite increases its flexibility and flexibility. For example, the control composite does not contain any cross-linked fibers and has a layer compression value of 12.9 g / gsm. The composite material 2 in which 50% of the fiber content is a crosslinked fiber is 5.
It has a layer compression value of 8 g / gsm. Increasing the amount of crosslinked fibers relative to the matrix fibers further increases flexibility and flexibility. Composite 3, whose 67% of its fiber content is crosslinked fibers, has a layer compression value of 1.9 g / gsm.

Replacing the crosslinked fibers in the composite with other substances such as CTMP (composite 4) or HPZ (composite 5) results in high ring crush values and low flexibility and flexibility. . Also, replacing the crosslinked fibers of the composite with an additional superabsorbent material (composite 6) reduces flexibility and flexibility. However, increasing the amount of superabsorbent material and maintaining a relatively high proportion of crosslinked fibers (about 50% based on the total weight of the fibers), compared to a typical wetlaid composite (Composite Material 2) The composite material (composite material 7) having high flexibility and flexibility is supplied. Also, the use of cellulose acetate instead of cross-linked fibers (Composite Material 14) resulted in a composite material having higher flexibility and flexibility than typical wet composite materials (Composite Material 2).

Replacing the matrix fibers in the composite with other fibers such as calcium carbonate coated fibers (composite 11) and synthetic (PET) fibers (composites 12 and 13) increases the flexibility and flexibility. A composite material having In addition, the debinding agent (de
The addition of a bonding agent reduced the flexibility and flexibility of the composite.

[0201] Mechanical and chemical treatment of the composite also increased the flexibility and flexibility of the composite. These effects are shown by comparing the ring crush value of composite material 2 with composite materials 19 and 21, respectively.

There is no relationship either between ring grinding and reference weight or between ring grinding and density for the composites evaluated. The flexibility and flexibility of the composite of the present invention can be dramatically increased by increasing the amount of superabsorbent and crosslinked fibers in the composite. Super absorbent material (40, 50 and 60% by weight), crosslinked fiber (10, 15, 25, 30 and 4)
Table 9 summarizes the flexibility and flexibility of representative composites composed of 5% by weight) and matrix fibers (10, 15, 25, 30, and 45% by weight). In Table 9, superabsorbent A refers to a superabsorbent obtained from Stockhausen, and superabsorbent B represents S
Refers to the superabsorbent material obtained under the name SXM-77 from tockhausen.

[0203]

[Table 9]

Referring to Table 9, for a given percentage of superabsorbent (40% by weight), the amount of crosslinked fiber was reduced from 45% to 15% and the matrix fiber was reduced from 15% to 45%.
Increases the flexibility and flexibility dramatically. Composite materials 21 and 25
When compared to composite materials 22 and 26, respectively, the over-layer compression increases about 5-fold (2.9 to 16.4 g / gsm and 3.0 to 16.4 g / g).
sm). Maintaining a 3: 1 ratio of crosslinked fibers to matrix fibers and increasing the amount of superabsorbent to 60% by weight further increases flexibility and flexibility significantly. When comparing composites 21 and 25 with composites 23 and 27, respectively, the layer compression value is reduced by more than about 5 times (from 2.9 to 1.1 g / gsm and 3.0).
To 1.4 g / gsm). Increasing the amount of superabsorbent from 40% to 60% results in high flexibility and flexibility even for composites where the ratio of crosslinked fibers to matrix fibers is 1: 3. When comparing the composites 24 and 28 with the composites 22 and 26, respectively, the layer compression value is reduced by a factor of about 3 (16.
4 to 5.0 g / gsm and 16.4 to 5.3 g / gsm).

The results show that for these representative composites, replacing the matrix fibers with either cross-linked fibers or superabsorbent materials reduces ring crushing and layer compression and increases flexibility and flexibility. Has proven to be improved. The correlation between ring milling and percent matrix fiber is shown graphically in FIG. Looking at FIG. 29, ring grinding increases dramatically as the percentage of matrix fiber increases.

Example 18 Representative Reticulated Absorbent Composite: Flexibility and Flexibility of Foam Sheets The flexibility of a representative reticulated absorbent composite formed by the foam-forming method according to the present invention. And the flexibility were measured by a layered ring crushing method and a layered compression method. A representative composite material is formed using a twin-wire former as described above, which includes 70% by weight of superabsorbent and 30% by weight of fiber. I was The first composite material contained 50% by weight of matrix fibers (NB416) and 50% by weight of crosslinked fibers based on the total weight of the fibers. The second composite material contained 30% by weight of matrix fibers (NB416) and 70% by weight of crosslinked fibers based on the total weight of the fibers. Both composite materials have a wet strength agent (
It contains a wet strength agent (polyamide-epichlorohydrin resin, 10 lb / ton fiber) and has a surface layer composed of matrix fibers (NB416, 40% by weight) and crosslinked fibers (60% by weight). I was The first composite is about 2.
The second composite had an average layer compression value of about 1.1 g / gsm, with an average layer compression value of 9 g / gsm. The results demonstrate that for these highly superabsorbent-containing composites, increasing the amount of cross-linked fibers significantly reduced the stretch compression and improved flexibility and flexibility. I have. For those composites containing 70% by weight of superabsorbent, increasing the percentage of crosslinked fibers in the fiber composite from 50% to 70% reduces ring crushing and pressure by about 2.5 times Flexibility and flexibility are increased.

Example 19 Softness and Wet Binding of Representative Reticulated Absorbent Composite ; Layered Compression Softness and Wet Binding of Representative Reticulated Absorbent Composite Formed by Wet Deposition and Foam Forming Method According to the Invention Properties were measured by creep compression. Coastal compression (edgewise)
compression) is Richard E. Mark's "The Handb
books of Physical and Mechanical Testi
ng of Paper and Paperboard "(Dekker, 1
983 (Vol. 1). As described above, the coastal compression (E
C) is an index of the softness of the dry absorbent composite.

The representative composite was formed as described above using a twin wire former and included 40% by weight of super absorbent and 60% by weight of fiber. First
Of the composite contained 80% by weight of matrix fiber (NB416) and 20% by weight of crosslinked fiber, based on the total weight of the fiber. The second composite contained 40 or 60% by weight of matrix fiber (NB416) and 60 or 40% by weight of crosslinked fiber based on the total weight of the fiber. One of the composites contained a wet reinforcement (polyamide epichlorohydrin resin). Referring to Table 10, composites 31-34 are wet-laid composites and composites 35-39 are foam-forming composites. Some of the composites were further processed after formation, for example, by calendering.

The EC values for the representative conjugates are summarized in Table 10. The values shown in the table represent the average of three repetitions.

[0210]

[Table 10]

The results show that foam molded composites are generally softer and softer than similarly configured wet-laid composites. Referring to Table 10, the wet deposited composites 31 and 33 had EC values of 10.8 and 11 g / gsm, respectively, while the foam molded composite 38 had an EC value of 8.4 g / gsm.

[0212] The effect of crosslinked fiber content on the flexibility and softness of the composite is shown by comparing the ring collision and EC values of composites 37 and 38. Complex 38 (40
: 12: 48) contains about 20% by weight of crosslinked fiber based on the total weight of the fiber and has an EC value of 8.4. Composite 37 (40:36:24) contains about 60% by weight of crosslinked fiber based on the total weight of the fiber and has an EC value of 2.8. As noted above, increasing the amount of cross-linked fibers significantly increases the flexibility and softness of the composite. In this example, increasing the crosslinked fiber ratio from 1: 4 to 3: 2 resulted in a three-fold increase in softness flexibility.

[0213] Mechanical treatment (eg, channeling or calendering) after formation of the composite increases the flexibility and softness of the composite by more than a factor of two and increases the EC value for composites 31 and 32 by 10%. From 0.8 to 4.3 and 8 for complexes 38 and 39
. Reduced from 4 to 2.7. For these composites, post-formation treatment did not significantly affect the composite body wet binding.

The composites 40-43 are foam-forming composites in which the matrix fiber (ie southern pine: southern pine) comprises 20% by weight polyethylene terephthalate fiber (PET224) and 10% by weight synthetic thermal bonding. binder fibers are replaced by a fiber blend comprising ^{(Celbond (R) T-105} ).

Example 20 Effect of Super Absorbent Polymer Particle Sizing Agent on Composite Flexibility and Softness The effect of super absorbent polymer particle size on the flexibility and softness of a representative composite of the present invention is described. Representative composites were formed as described above using the foamed twin wire method. The composite comprises 60% by weight of super absorbent particles, 20% by weight
Matrix fiber (southern pin, NB416) and 20% by weight of crosslinked fiber. The composite also contained a wet strength agent (polyamide-epichlorohydrin, 10 lb / fiber ton). The superabsorbent polymer particles introduced into these representative composites include lightly crosslinked polyacrylates: (1) Superabsorbent A from Stockhausen; (2) SXM77, and (3) about 0.5. Sieving SXM77 having a particle size in the range of ~ 1.0 mm.

Table 11 summarizes the measured ring collision, saturation capacity (oven drying), tensile strength, wicking, and basis weight for Composites 43-45. Composites 43-45 each contained the components described above, and superabsorbent polymer particles A, SXM77 and sieved SXM77.

[0219]

[Table 11]

Referring to Table 11, the results show that composites incorporating sieved superabsorbent polymer particles having a particle size in the range of about 0.5 to about 1.0 mm show the corresponding unsieved superabsorbent composites. G / gs for a similarly formed composite containing the agent polymer particles
It shows that it had a layer compression value of 3.2 g / gsm compared to m. The layer compression values for composites incorporating the sieved super absorbent polymer particles are about 1.6 times lower than the corresponding composites, indicating their increased flexibility and softness.

Also, the composites incorporating the sieved superabsorbent polymer particles had an increase in saturation capacity of about 10% compared to the corresponding composites containing unsieved superabsorbent polymer particles.

Example 21 Tensile Strength of Representative Reticulated Absorbent Composite: Wet Deposition Handsheet The tensile strength of a representative reticulated absorbent composite formed according to the present invention was determined by TAPPI method T.
It was measured according to the method described in 494 om-96-T.

A representative conjugate was made as described in Example 11. Table 12 summarizes the creep and dry tensile strengths of the representative composites. In this table, the control composites consist of super absorbent particles (40% by weight) and matrix fibers (60%).
Wt.%, Southern pin, and composite 2 comprises superabsorbent particles (40 wt.%), Matrix fiber (30 wt.%, Southern).
pin) and crosslinked fibers (30% by weight).

[0222]

[Table 12]

The correlation between composite layer compression and dry tension is shown graphically in FIG. Referring to FIG. 30, as the dry tension increases, the stratified compression increases dramatically. In general, as the tensile strength increases, the flexibility and softness of the composite decreases. No correlation is found between composite basis weight and dry tension, but there is some correlation between composite density and dry tension.

Example 22 Absorption Characteristics of Representative Reticulated Absorbent Composite: Foam-Forming Composite A representative composite was prepared by the foam-forming method according to the method described above. The composite comprises an absorbent (about 35 to about 45% by weight of the absorbent particles based on the total weight of the composite) crosslinked fibers, and matrix fibers (crosslinked fiber: matrix fiber weight ratio, 1: 1). Included. Table 13 summarizes the composition and physical properties of the representative composites (Complexes 46-48).

[0225]

[Table 13]

The absorption properties of these representative complexes include (1) unconstrained wicking height, (2) acquisition rate and rewet, (3) saddle acquisition rate,
It was determined by measuring 4) saddle acquisition wicking distribution and (5) saddle acquisition wicking height.

The unconstrained suction height at an unconstrained suction height of 15 minutes was measured using the above composite (ie,
The measurements were made on unsoftened compositions 43-45) and the corresponding calendered composites as described below.

Materials: Artificial urine for wicking-"Blood Bank" 0.9% salt solution Sample: Dimensions: 6.5 cm (CD) x 2.5 cm (MD), 1,11 16, along MD. And at 21 cm were marked with both permanent and water permeable lines.

Method: 1) Perform% solids of sample and record. 2) Cut the sample and record the weight (as is) and the dry thickness. 3) Hold the sample at 1 cm from the top. 4) Immerse in liquid to 1 cm line. 5) Start timing immediately. 6) At the end of 5, 10 and 15 minutes, record the wicking height by taking down from the next highest line. Determine the wicking height to the nearest 0.5 cm. 7) At 15 minutes, cut the sample that has risen out of the fluid and remains clamped at 1 cm and 15 cm high lines. Discard the 1cm part. 8) Measure and record a wet 15 cm long sample. 9) The remaining sample was unclamped and added to the rest to record the total pad wet weight. 10) Report the total wicking height at 15 minutes. 11) As it is and by the following calculation. D. The basal total pad capacity (g / g) is reported. Total pad capacity (g / g) = {wet weight-(weight as it is or OD weight)
*｝ / (As is or OD weight) * pad weight (-1 cm portion) = (total sample weight × 0.96). 15) Calculate the capacity of the wicked pad if necessary. The capacity of the wicked pad = the total pad capacity × 24 / (wicking height in 15 minutes).

The results are summarized in Table 4.

[0231]

[Table 14]

The results show that the wicking height is reduced by calendaring. This result also suggests that calendering disrupts the fiber network and leads to efficient wicking of the entire composite.

Acquisition Rate and Rewetting The acquisition rate and rewet of a typical composite were determined by the method described above in Example 4. In addition to the acquisition rates and rewet measurements of the three liquid pushes for composite 48, the acquisition rates for composites 47 and 48 in combination with pledget were also determined. For these structures, the pledget acts as an acquisition / distribution layer. Table 15 summarizes the results.

[0234]

[Table 15]

[0235] The result is that the acquisition speed is slightly reduced in the subsequent push.
And that the addition of pledget slightly reduces the acquisition rate. However, the rewet measured for structures containing the pledget is less than the rewet for structures without the pledget.

Saddle acquisition speed, distribution and wicking height Saddle wicking, including acquisition speed, distribution and wicking height, was determined by the following method. Procedure: 1) Test three times. 2) Perform% solids on the material. The sample is cut into 43 cm x (6.5 cm to 11 cm, depending on the sample). 3) Measure (as is) the weight and caliper of the sample. Calculate basis weight and density. 4) Pull and label 12 cells using template and permanent marker. 5) Construct a Diaper by instructions in the service request. (This can result in exchanging a portion of a diaper (ie, the core) with the sample). 6) Place the diaper in the saddle device so that the "X" is at the four corners at the bottom of the device,
Thereafter, the funnel is positioned approximately 1 cm directly above "X". 7) Measure out 75 ml of synthetic urea (Blood Bank 0.9% saline) and pour into funnel. 8) Open the funnel and start the timer. Measure the time that all of the fluid goes from the funnel to the point where the fluid is absorbed into the sample. Record as SWAT. 9) At the end of 20, 40 and 60 minutes, repeat steps 7 and 8. 10) When the timer reached 80 minutes, the diaper was removed and the sample was cut into the named cell. 11) Each cell was pulled apart, weighed, and the weight recorded. 12) If necessary, perform a wet caliper measurement.

The saddle acquisition rate results for composite 45 in combination with pledget were compared to the control composite (Suprem commercially available from Kimberly-Clark, Nina, WI).
e Diaper) and summarized in Table 16.

[0238]

[Table 16]

The results show that the acquisition rate generally increased with subsequent rushing, and that the acquisition rate for composites 48 and structures including pledgets was less than for commercially available cores. Is shown.

The saddle gain distribution for composite 48 in combination with pledget was compared to the control composite and is summarized in Table 17.

[0241]

[Table 17]

The results show that the representative composite has a relatively effective distribution of the obtained liquid throughout the composite. Saddle acquisition wicking heights for composite 48 in combination with pledget are compared to control composites and are summarized in Table 18.

[0243]

[Table 18]

The results show that the composite including composite 45 and pledget has a wicking height comparable to the control composite (commercially available from Kimberly-Clark, Nina, Wis., Taken from Supreme Core). It shows that it has.

While the preferred embodiments of the invention have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

[Brief description of the drawings]

The foregoing aspects and attendant advantages of the present invention will become more readily apparent when taken in conjunction with the accompanying drawings, by reference to the following detailed description. In these drawings:

FIG. 1 is a cross-sectional view of a portion of a network absorbent composite formed in accordance with the present invention;

FIG. 2 is a photomicrograph at 12 × magnification of a cross section of a representative resorbable composite formed according to the present invention by the wet laid method;

FIG. 3 is a photomicrograph of the wetlaid composite of FIG. 2 at 40 × magnification;

FIG. 4 is a photomicrograph at 12 × magnification of a cross section of a representative resorbable composite formed according to the present invention by the foam method;

5 is a photomicrograph of the foam-forming composite of FIG. 4 at 40 × magnification;

FIG. 6 is a photomicrograph, at 8 × magnification, of a cross section of a representative reticulated absorbent composite formed according to the present invention by the wet laid method;

FIG. 7 is a photomicrograph at 12 × magnification of the wet laid complex of FIG. 6;

FIG. 8 is a photomicrograph at 8 × magnification of a cross section of a representative reticulated absorbent composite formed in accordance with the present invention by the foam method;

FIG. 9 is a photomicrograph at 12 × magnification of the foam-forming composite of FIG. 8;

FIG. 10 is a cross-sectional view of a portion of an absorbent construct incorporating a reticulated absorbent composite formed in accordance with the present invention;

FIG. 11 is a cross-sectional view of a portion of another absorbent construct incorporating a network absorbent composite formed in accordance with the present invention;

FIGS. 12A and 12B are cross-sectional views of a portion of an absorbent article that incorporates a reticulated absorbent composite formed in accordance with the present invention;

FIG. 13 is a cross-sectional view of a portion of another absorbent article incorporating a reticulated absorbent composite formed in accordance with the present invention;

FIG. 14 is a cross-sectional view of a portion of another absorbent article incorporating a reticulated absorbent composite formed in accordance with the present invention;

FIG. 15 is a cross-sectional view of a portion of an absorbent construct incorporating a network absorbent composite formed in accordance with the present invention;

FIG. 16 is a cross-sectional view of a portion of another absorbent construct incorporating a network absorbent composite formed in accordance with the present invention;

FIG. 17 is a cross-sectional view of a portion of another absorbent construct incorporating a network absorbent composite formed in accordance with the present invention;

FIG. 18 is a cross-sectional view of a portion of an absorbent article incorporating a network absorbent composite formed in accordance with the present invention;

FIG. 19 is a cross-sectional view of a portion of another absorbent article that incorporates a reticulated absorbent composite formed in accordance with the present invention;

FIG. 20 is a cross-sectional view of a portion of another absorbent article that incorporates a reticulated absorbent composite formed in accordance with the present invention;

FIGS. 21A and B are cross-sectional views of a portion of a reticulated absorbent composite formed in accordance with the present invention;

FIG. 22 illustrates a twin-wire device and a method of forming a composite of the present invention;

FIG. 23 illustrates an exemplary headbox assembly and a method of forming the composite of the present invention;

FIG. 24 is a cross-sectional view of a portion of an absorbent construct incorporating an acquisition layer and a network absorbent composite formed in accordance with the present invention;

FIG. 25 is a cross-sectional view of a portion of an absorbent construct incorporating an acquisition layer, an intermediate layer, and a network absorbent composite formed in accordance with the present invention;

FIG. 26 is a cross-sectional view of a portion of an absorbent article incorporating a network absorbent composite formed in accordance with the present invention;

FIG. 27 is a cross-sectional view of a portion of an absorbent article incorporating an acquisition layer and a reticulated absorbent composite formed in accordance with the present invention;

FIG. 28 is a cross-sectional view of a portion of an absorbent article incorporating an acquisition layer, an intermediate layer, and a network absorbent composite formed in accordance with the present invention;

FIG. 29 is a graph showing the correlation between edgewise compression of a composite and the percentage of matrix fibers in the composite;

FIG. 30 is a graph showing a correlation between dry tensile strength and edge compression of a composite.

[Procedure amendment]

[Submission date] May 29, 2001 (2001.5.29)

[Procedure amendment 1]

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[Table 1]

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[0203]

[Table 9]

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[0222]

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[0225]

[Table 13]

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[Table 18]

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) A61F 13/534 A61F 13/18 302 B32B 5/26 303 // D06M 15/263 307C 15/59 360 GS (81) Designated countries EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE), OA (BF, BJ , CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, TZ, UG) , ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, B , BR, BY, CA, CH, CN, CR, CU, CZ, DE, DK, DM, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS, JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MA, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT , RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, TZ, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Mirror, Charles E. One Hundred and Second Place Southeast 22625 (72), Kent, 98031, Washington, USA Inventor Bolstad, Clifford Ears 98003, Federal Way, South, Washington, USA Three Handed and Seventies Court 1938 (72) Inventor Colin, Elston 7307 (72) Inventor Drive, Northwest 9898, Gig Harbor, Washington, USA Marsh, David G. 98003, Washington, USA Edmark, Richard A. East Crescent Drive, Seattle, Seattle 98112, USA 2245 (72) Inventor Li, Federal Way, South West Three Hundred and 30th Street , Yon, 98422, Washington, USA Tacoma, Northeast 45th Avenue 3803 F-term (reference) 3B029 BA05 BA12 BA15 BA17 BD13 BD18 BD19 BF03 4C003 AA09 AA16 AA18 AA29 GA02 4C098 AA09 CC03 CC12 DD06 DD24 DD26 DD28 4F100AJA AK41A AK42A AK46A AL05A BA02 DC16A DG01A DG01B DG06A DJ01A EJ08A GB72 JB10A JD05C JD14 JD14A JK07A JK17A YY00A 4L033 AA02 AA05 AA07 AA08 AB01 AC07 CA18 CA49 CA55

Claims (78)

[Claims] 1. An absorbent composite comprising a reticulated core and a first fibrous layer, wherein the core and the layer are integrally formed; wherein the layer is coextensive with an outer surface of the core; The core comprising a fiber matrix and an absorbent material, the fiber matrix defining voids and void passages substantially distributed throughout the matrix, wherein the absorbent material is located within some of the voids; And the absorbent material located within the void is expandable into the void. 2. The composite of claim 1, wherein the fiber matrix comprises fibers selected from the group consisting of elastic fibers, matrix fibers, and mixtures thereof. 3. The method of claim 2, wherein the elastic fibers are selected from the group consisting of chemically cured fibers, flexible fibers, chemi-thermomechanical pulp, pre-hydrolyzed kraft pulp, synthetic fibers, and mixtures thereof. The conjugate of claim 1. 4. The composite of claim 3, wherein the chemically cured fibers comprise crosslinked cellulosic fibers. 5. The composite according to claim 3, wherein the synthetic fibers are selected from the group consisting of polyolefin, polyester, and polyamide fibers. 6. The composite according to claim 6, wherein the polyester fiber is a polyethylene terephthalate fiber. 7. The composite according to claim 1, wherein the matrix fibers include cellulose fibers. 8. The composition of claim 2, wherein the elastic fibers are present in the composite in an amount of about 5 to about 60 weight percent of the total composite. 9. The composite of claim 2, wherein the matrix fibers are present in the composite in an amount of about 10 to about 60 weight percent of the total composite. 10. The composite according to claim 1, wherein the absorbent material is a super absorbent material. 11. The composite of claim 1, wherein the absorbent material is present in an amount from about 5 to about 60 weight percent of the total composite. 12. The composite of claim 1, further comprising a wet strength agent. 13. The composite of claim 12, wherein the wet strength agent is a resin selected from the group consisting of polyamide-epichlorohydrin and polyacrylamide resin. 14. The composite of claim 12, wherein the wet strength agent is present in the composite in an amount from about 0.01 to about 2 weight percent of the total composite. 15. The composite according to claim 1, wherein the composite is formed by a wet laid method. 16. The composite according to claim 1, wherein the composite is formed by a foam method. 17. A second layer, opposite to the first layer and coextensive with the outer surface of the core.
The composite of claim 1, further comprising a layer. 18. The composite according to claim 1, wherein the core and the layer are formed from the same fiber furnish. 19. The composite according to claim 1, wherein the core and the layers are formed from different fiber furnishes. 20. The composite of claim 17, wherein the first and second layers are formed from the same fiber furnish. 21. The composite of claim 17, wherein the first and second layers are formed from different fiber furnishes. 22. The core of claim 1, wherein the core has a basis weight different from the basis weight of the layer.
The complex according to any one of the above. 23. The composite of claim 17, wherein the first layer has a basis weight different from the basis weight of the second layer. 24. The composite of claim 17, wherein the first and second layers have the same basis weight. 25. An absorbent article in which the composite according to claim 1 is incorporated. 26. The absorbent article according to claim 25, wherein the article is at least one of a diaper, a women's care product, and an adult incontinence product. 27. An absorbent article incorporating the composite according to claim 17. 28. The absorbent article according to claim 27, wherein the article is at least one of a diaper, a women's care product, and an adult incontinence product. 29. An absorbent article comprising a reticulated core and a fibrous layer, the core and the layer comprising an integrally formed absorbent composite; the layer coextensive with an outer surface of the core. The core comprises a fibrous matrix and an absorbent material, the fibrous matrix defining voids and void passages substantially distributed throughout the matrix, wherein the absorbent material comprises some interior of the voids. And the absorbent material located within the void is expandable into the void. 30. A second co-extensive with the outer surface of the core opposite the fibrous layer.
30. The absorbent article according to claim 29, further comprising a layer. 31. A liquid permeable topsheet comprising a reticulated core and a fibrous layer, wherein the core and the layer are integrally formed absorbent composites, the layer coextensive with the outer surface of the core. Wherein the core comprises a fibrous matrix and an absorbent material, the fibrous matrix defining voids and void passages substantially distributed throughout the matrix; the absorbent material comprising some of the voids. A storage layer comprising an absorbent composite, the storage layer comprising an absorbent composite; and a liquid impervious backsheet, wherein the absorbent material located within the cavity is expandable into the cavity. . 32. A second co-extending surface opposite to the fiber layer and coextensive with the outer surface of the core.
32. The absorbent article according to claim 31, further comprising a layer. 33. A liquid-permeable topsheet; an acquisition layer for quickly acquiring and distributing liquid; a reticulated core and a fiber layer, wherein the core and the layer are an integrally formed absorbent composite. Wherein the layer is coextensive with an outer surface of the core, the core includes a fiber matrix and an absorbent material, the fiber matrix defining voids and void passages distributed substantially throughout the matrix. A storage layer comprising an absorbent composite, wherein the absorbent material is located within some of the voids; and wherein the absorbent material located within the voids is expandable into the voids; And a liquid-impermeable backsheet. 34. A second coextensive face with the outer surface of the core opposite the fibrous layer.
34. The absorbent article according to claim 33, further comprising a layer. 35. A liquid-permeable topsheet; an acquisition layer for quickly acquiring and distributing liquid; a reticulated core and a fiber layer, wherein the core and the layer are an integrally formed absorbent composite. Wherein the layer is coextensive with an outer surface of the core, the core includes a fiber matrix and an absorbent material, the fiber matrix defining voids and void passages distributed substantially throughout the matrix. A storage layer comprising an absorbent composite, wherein the absorbent material is located within some of the voids; and wherein the absorbent material located within the voids is expandable into the voids; An intermediate layer interposed between the acquisition layer and the storage layer; and a liquid-impermeable backsheet. 36. A second coextensive with the outer surface of the core opposite the fibrous layer.
36. The absorbent article according to claim 35, further comprising a layer. 37. The absorbent article according to claim 33, further comprising leg gathers. 38. A method for forming an absorbent composite, comprising: combining an elastic fiber, a matrix fiber, and an absorbent material in a dispersion medium to form a fiber slurry; Depositing on the body to form a wet composite; removing water from the deposited slurry to obtain a web composite having a fibrous layer formed adjacent to the support; and Drying, comprising a reticulated core and a fibrous layer, wherein the core and the layer are an integrally formed absorbent composite, wherein the layer is coextensive with an outer surface of the core; A fibrous matrix comprising a matrix and an absorbent material, the fibrous matrix defining voids and void passages substantially distributed throughout the matrix; the absorbent material being located within some of the voids; and the voids Within How the absorbent material comprises is expandable towards the inside voids, step for forming an absorbent composite, a to. 39. The method of claim 38, wherein the elastic fibers comprise cross-linked cellulose fibers. 40. The method according to claim 38, wherein the matrix fibers comprise wood pulp fibers. 41. The method of claim 38, wherein the absorbent material comprises a superabsorbent material. 42. The fiber slurry further comprises a wet strength agent.
The method described in. 43. The method according to claim 42, wherein the wet strength agent is a polyamide-epichlorohydrin resin. 44. The method according to claim 38, wherein the method is a wet laid method. 45. The method according to claim 38, which is a foam method. 46. The method of claim 38, wherein the composite further comprises a second layer coextensive with the outer surface of the core opposite the fibrous layer. 47. A method for forming an absorbent composite comprising: combining an elastic fiber and a matrix fiber in a first dispersion medium to form a first fiber slurry; and combining the absorbent material with a second dispersion medium. Forming an absorbent material slurry in combination with the first fiber slurry to obtain a second fiber slurry; depositing the second fiber slurry on a perforated support; Removing water from the deposited slurry to obtain a wet composite having a fibrous layer formed adjacent to the support;
And drying the wet composite, comprising a reticulated core and a fibrous layer, the core and the layer being an integrally formed absorbent composite, wherein the layer is coextensive with the outer surface of the core. Wherein the core comprises a fiber matrix and an absorbent material, the fiber matrix defining voids and void passages distributed substantially throughout the matrix; the absorbent material being within some of the voids. And forming the absorbent composite, wherein the absorbent material located within the void is expandable into the void. 48. The fiber slurry according to claim 47, further comprising a wet strength agent.
The method described in. 49. The method of claim 47, wherein the composite further comprises a second fibrous layer opposing the fibrous layer and coextensive with an outer surface of the core. 50. A method for forming a fibrous web, comprising: (a) forming a first foam slurry containing fibers and a surfactant in an aqueous dispersion medium; (b) fibers in an aqueous dispersion medium. And (c) moving the first perforated element in the first passage; and (d) moving the second perforated element in the second passage. (E) the step of passing the first foam slurry and contacting the first perforated element moving in the first passage; (f) the second step of passing the second foam slurry and moving in the second passage. (G) passing a third material between the first and second foam slurries, wherein the third material does not contact the perforated element; From the first and second foam slurries and the third material How to remove the foam and liquid, including stroke, to obtain a fibrous web and through the second perforated element. 51. The method of claim 50, wherein the fibers are selected from the group consisting of elastic fibers, matrix fibers, synthetic fibers, and mixtures thereof. 52. The method of claim 50, wherein the fibers include crosslinked cellulosic fibers and wood pulp fibers. 53. The method of claim 50, wherein at least one of the first and second foam slurries further comprises a wet strength agent. 54. The method of claim 50, wherein the third material comprises an absorbent material. 55. The method of claim 50, wherein the third material comprises an aqueous suspension of a superabsorbent material. 56. The method according to claim 50, wherein the third material comprises a fiber slurry. 57. The method of claim 50, wherein the first foam slurry is different from the second foam slurry. 58. The method of claim 50, wherein the first and second passages are substantially vertical. 59. The method of claim 50, implemented in a twin wire former. 60. The twin-wire former is a vertical downflow former.
The method according to 0. 61. The step of passing a third material between the first and second foam slurries comprises contacting the first and second foam slurries with first and second perforated elements, respectively, and removing foam and 51. The method of claim 50, comprising passing a third material between the first and second foam slurries after removing the liquid. 62. The method of claim 50, further comprising drying the wet composite to obtain an absorbent composite. 63. The step of passing a third material between the first and second foam slurries comprises contacting the first and second foam slurries with first and second perforated elements, respectively, and removing the foam and 51. The method of claim 50, comprising passing a third material between the first and second foam slurries after removing the liquid. 64. An absorbent composite comprising an absorbent material in a fibrous matrix, wherein the composite has a truncated ring crush value in the range of about 400 to about 1600 grams / inch and about 250 to about 650 grams. An absorbent composite having a basis weight in the range: 65. The absorbent material comprises from about 5 to about 6 based on the total weight of the composite.
65. The conjugate of claim 64, which is present in an amount of 0 weight percent. 66. The composite of claim 64, wherein the fiber matrix comprises crosslinked cellulosic fibers in an amount of about 5 to about 60 weight percent based on the total weight of the composite. 67. The composite of claim 64, wherein the fiber matrix comprises matrix fibers in an amount of about 10 to about 60 weight percent based on the total weight of the composite. 68. The composite of claim 64, wherein the absorbent material is present at about 60 weight percent based on the total weight of the composite, wherein the fibrous matrix is about 30% based on the total weight of the composite. A composite comprising crosslinked fibers present in weight percent and wherein the matrix fibers are present in about 10 weight percent based on the total weight of the composite. 69. The composite of claim 64, wherein the absorbent material is present in an amount from about 40 to about 80 weight percent based on the total weight of the composite. 70. The composite of claim 64, wherein the fiber matrix comprises crosslinked cellulosic fibers in an amount of about 10 to about 50 weight percent based on the total weight of the composite. 71. The composite of claim 64, wherein the fiber matrix comprises matrix fibers in an amount of about 5 to about 30 weight percent based on the total weight of the composite. 72. An absorbent composite comprising an absorbent material in a fiber matrix, wherein the absorbent material comprises from about 40 to about 80 weight percent of the composite in the composite, based on the total weight of the composite. Wherein the fiber matrix comprises cross-linked cellulosic fibers and matrix fibers; the weight ratio of cross-linked fibers to matrix fibers is at least about 3: 1; and the composite comprises from about 400 to about 1600 grams / inch. An absorbent composite having a range of edge ring crush values. 73. An absorbent composite comprising an absorbent material in a fiber matrix, wherein the absorbent material comprises about 60 to about 80 weight percent of the composite in the composite, based on the total weight of the composite. Wherein the fiber matrix comprises crosslinked cellulosic fibers and matrix fibers; wherein the weight ratio of crosslinked fibers to matrix fibers is at least about 1: 1; and wherein the composite comprises from about 400 to about 1600 grams / inch. An absorbent composite having a range of edge ring crush values. 74. The composite of claim 73, wherein the weight ratio of crosslinked fibers to matrix fibers is at least about 2: 1. 75. The composite of claim 73, wherein the weight ratio of crosslinked fibers to matrix fibers is at least about 3: 1. 76. An absorbent article incorporating the composite according to claim 64, 72 or 73. 77. The absorbent article according to claim 80, which is at least one of a diaper, a women's care product, and an adult incontinence product. 78. An absorbent composite comprising an absorbent material in a fibrous matrix, comprising: a truncated ring crush value in the range of about 400 to about 1600 grams / inch; Weight, and about 50 to about 8
An absorbent composite having a dry tensile strength in the range of 00 g / inch.