JP2915354B2 - Absorbent macrostructures for improved fluid handling capacity made from a mixture of different hydrogel-forming absorbent polymers - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a porous absorbent macrostructure containing flexible interparticle aggregates. The present invention specifically relates to a porous absorbent made from a mixture of particulate absorbent polymers having different fluid handling properties or shapes or both, where the interparticle bonded aggregates impart improved fluid handling capabilities to the macrostructure. Macroscopic structure.

[0002]

BACKGROUND OF THE INVENTION The development of disposable diapers, adult incontinence pads and briefs, and superabsorbent members for use as sanitary articles, such as sanitary napkins, is a substantial commercial development. The subject of interest. Highly desirable properties for such products are:
It is thin. For example, thinner diapers are less bulky to wear, fit better under clothing, and are less bothersome. They are also more compact when packaged, making diapers easier for consumers to carry and store. The compactness of packaging also reduces the cost of distribution for manufacturers and distributors, including less shelf space for storage per diaper unit.

[0003] The ability to provide thinner absorbent articles, such as diapers, has depended on the ability to develop relatively thin absorbent cores or structures that can capture and store large amounts of bodily fluids, especially urine. In this regard, the use of certain absorbent polymers (often referred to as "hydrogel", "superabsorbent" or "hydrocolloid" materials) was of particular importance.
For example, US Patent No. 3,6, issued June 13, 1972, which discloses the use of such an absorbent polymer (hereinafter "hydrogel-forming absorbent polymer") in an absorbent article.
See U.S. Patent No. 99,103 (Harper et al.) And U.S. Patent No. 3,770,731 issued June 20, 1972 (Harmon). In fact, the development of thinner diapers
Typically, when used in combination with a fibrous matrix, it immediately resulted in a thinner absorbent core that would benefit from the ability of these hydrogel-forming absorbent polymers to absorb large amounts of bodily fluids. For example, it discloses a two-layer core structure comprising a fibrous matrix and a hydrogel-forming absorbent polymer useful in making thin, compact, bulky diapers.
US Patent No. 4,673,40 issued June 16, 987
No. 2 (Wiseman et al.) And June 19, 1990
See U.S. Pat. No. 4,935,022 issued to Rush, et al.

Prior to the use of these hydrogel-forming absorbent polymers, it is common practice to form absorbent structures, such as those suitable for use in infant diapers, all from wood pulp fluff. there were. Assuming a relatively small amount of fluid absorbed by wood pulp fluff per gram of fluid absorbed per gram of wood pulp,
It was necessary to use a relatively large amount of wood pulp fluff, and therefore a relatively bulky and thick absorbent structure. The incorporation of these hydrogel-forming absorbent polymers into such structures has allowed the use of less wood pulp fluff. These hydrogel-forming absorbent polymers can be used in large volumes of aqueous bodily fluids such as urine (ie,
(At least about 15 g / g) and thus is superior to fluff in its ability to make smaller and thinner absorbent structures workable.

[0005] These hydrogel-forming absorbent polymers are:
Often produced by first polymerizing an unsaturated carboxylic acid or a derivative thereof, such as acrylic acid, alkali metal salts of acrylic acid (eg, sodium and / or potassium salts) or ammonium salts, alkyl acrylates, and the like. . In these polymers, the carboxyl-containing polymer chains are slightly cross-linked with conventional di- or polyfunctional monomeric substances, such as N, N'-methylenebisacrylamide, trimethylolpropane triacrylate or triallylamine. By
It is made water-insoluble and water-swellable. These slightly crosslinked absorbent polymers still contain a large number of anionic (charged) carboxyl groups attached to the polymer backbone.
It is these charged carboxy groups that allow the polymer to absorb body fluids as a result of osmotic forces and thus form a hydrogel.

[0006] The degree of cross-linking not only determines the water insolubility of these hydrogel-forming absorbent polymers, but also an important factor in establishing two other properties of these polymers: absorption capacity and gel strength. Become. Absorption capacity or "gel volume" is a measure of the amount of water or body fluid that a given amount of hydrogel-forming polymer will absorb. Gel strength is related to the tendency of hydrogels formed from these polymers to deform or “flow” under applied stress. Hydrogel-forming polymers useful as absorbents in absorbent structures and articles, such as disposable diapers, need to have a suitably high gel volume as well as a suitably high gel strength.
The gel volume needs to be high enough to allow the hydrogel-forming polymer to absorb significant amounts of aqueous bodily fluids encountered during use of the absorbent article. Gel strength is
The formed hydrogel does not unacceptably deform and fill the capillary void space in the absorbent structure or article, thereby reducing the absorbent capacity of the structure / article and the fluid distribution throughout the structure / article. It must be something that does not suppress. For example, 1987 3
U.S. Pat. No. 4,654,039 (Blunt et al.) (May 31, 31) (reissued on Apr. 19, 1988 as U.S. Pat. No. Re. 32,649) and 198.
See U.S. Pat. No. 4,834,735 issued May 30, 9 (Alemeni et al.).

[0007] Conventional absorbent structures have generally included relatively small amounts (eg, up to about 50% by weight) of these hydrogel-forming absorbent polymers. For example, 1989 5
See U.S. Pat. No. 4,834,735, issued Aug. 30, (Alemeni et al.) (Preferably about 9 to about 50% of a hydrogel-forming absorbent polymer in a fibrous matrix). There are several reasons for this. Hydrogel-forming absorbent polymers used in conventional absorbent structures generally do not have an absorption rate that would allow rapid absorption of bodily fluids, especially under "squirt" situations. This required the incorporation of fibers, typically wood pulp fibers, to serve as a reservoir to hold the excreted fluid until absorbed by the hydrogel-forming absorbent polymer.

[0008] More importantly, many of the known hydrogel-forming absorbent polymers exhibited gel occlusion, especially when incorporated in large amounts into absorbent structures. “Gel occlusion” wets the particles of the hydrogel-forming absorbent polymer and occurs as the particles swell, inhibiting fluid transport to other areas of the absorbent structure. Therefore, wetting of these other areas of the absorbent member is caused by a very slow diffusion process. As a practical matter, this means that the capture of fluid by the absorbent structure is much slower than the rate at which fluid is excreted, especially in a blast situation. Leakage from the absorbent article may well saturate the particles of the hydrogel-forming absorbent polymer in the absorbent member, or may allow fluid to diffuse the "occluded" particles to the rest of the absorbent member or wick. Can occur before.

Gel occlusion is a particularly serious problem when the particles of the hydrogel-forming absorbent polymer do not have the proper gel strength and once the particles swell with the absorbed fluid and deform or spread under stress. It may be. May 3, 1989
See U.S. Pat. No. 4,834,735, issued on Day 0 (Alemeny et al.). Low gel strength hydrogel-forming absorbent polymers also tend to have higher fluid capacity. Gel strength can be increased by surface crosslinking of these higher fluid capacity hydrogel-forming absorbent polymers. Unfortunately, surface cross-linking increases gel strength, which also tends to reduce the fluid capacity of the hydrogel-forming absorbent polymer.

Gel occlusion can also occur when the hydrogel-forming absorbent polymer is in the form of regularly shaped particles, such as spherical particles. Spherical particles typically occur when the hydrogel-forming absorbent polymer is formed by a multiphase polymerization processing technique such as inverse emulsion polymerization, inverse suspension polymerization, and the like. U.S. Patent No. 4,34, issued July 20, 1982
No. 0,706 (Obayashi et al.), U.S. Pat. No. 4,506,052 issued Mar. 19, 1985 (Fresher et al.) And U.S. Pat. No. 4,735 issued Apr. 5, 1988. , 987 (Morita et al.). Because these spherical particles are prone to gel plugging, multiphase polymerization processing techniques are considered less desirable in synthesizing hydrogel-forming absorbent polymers.
US Patent No. 5,124,1 issued June 23, 1992
No. 88 (Loe et al.).

In order to improve capillary performance and thus minimize gel plugging, the particles of these hydrogel-forming absorbent polymers, typically in the form of sheets or strips, form interparticle crosslinked aggregates. Formed into a macro structure. These aggregate macrostructures have been prepared by first mixing particles of a hydrogel-forming absorbent polymer with a solution of a nonionic crosslinker such as glycerol, water and a hydrophilic organic solvent such as isopropanol. 1
U.S. Pat. No. 5,102,597 issued Apr. 7, 992
No. 5,124,188 issued June 23, 1992 (Loe et al.), And US Pat. No. 5,149,3 issued September 22, 1992.
See No. 44 (Lalman et al.). June 23, 1994, discloses an improved porous aggregate macrostructure in which particles of a hydrogel-forming absorbent polymer are cross-linked with a cationic amino-epichlorohydrin adduct such as KYMENE.
See also U.S. Patent No. 5,324,561 issued to Japan (Rezai et al.).

[0012] Because the particulate nature of the absorbent polymer is retained, these macrostructures are formed by adjacent particles that are interconnected such that the macrostructure is fluid permeable (ie, having a capillary transport channel). Give pores between. The resulting macrostructure also has improved structural integrity, increased fluid entrapment and distribution rates, and minimal gel occluding properties due to the interparticle cross-links formed between the particles.
Even so, the fluid handling capacity of these macrostructures is still somewhat dependent on the fluid handling capacity of the raw hydrogel-forming absorbent polymer particles. For example,
Macrostructures made from low gel strength hydrogel-forming absorbent polymers or spherical particles of hydrogel-forming absorbent polymers are still potentially susceptible to gel occlusion. Also, macrostructures made from surface-crosslinked hydrogel-forming absorbent polymers still have less than optimal penetration properties.

Thus, (1) hydrogel-forming absorbent polymers made by various methods can be used,
(2) an absorbent aggregate macrostructure of bound absorbent particles that has a reduced tendency to occlude gels, (3) has optimal permeation properties, and / or (4) provides an improved combination of fluid handling capabilities. It would be desirable to be able to make.

[0014]

SUMMARY OF THE INVENTION The present invention is directed to a porous absorbent macrostructure having improved fluid handling capabilities including interparticle bonded aggregates. These agglomerates consist of a number of interconnected cross-linked particles consisting of substantially water-insoluble absorbent hydrogel-forming polymeric material. The hydrogel-forming polymeric material comprises: (a) Saline Flow Conducti
vity) (SFC) value at least about 5 × 10 ⁻⁷ cm ³ s / g
And about 50 to about 95% of a first hydrogel-forming polymer having a performance under pressure (PUP) capacity value of at least about 23 g / g at 0.7 psi (5 kPa) confinement pressure and an absorption capacity value of at least About 25g / g
(B) a mixture of about 20 to about 40% of the first hydrogel-forming polymer in the form of spherical particles and a second hydrogel-forming polymer in the form of non-spherical particles. About 60% to about 80%, and (c) a mixture selected from the group consisting of a combination of (a) and (b). The interparticle bonded aggregate contains pores between adjacent particles. The pores are interconnected by interconnecting channels to form a liquid permeable macrostructure.
The circumscribed dry volume of this macrostructure is about 0.008 mm ³
That is all.

The porous absorbent macrostructure according to the present invention can be used alone or in combination with another absorbent material to absorb various absorbent articles including diapers, adult incontinence pads, sanitary napkins and the like. Useful for things. These porous absorbent macrostructures provide a particularly desirable combination of fluid handling properties, including relatively high fluid permeability and relatively high fluid capacity. The macrostructures of the present invention can also be made from a wide variety of hydrogel-forming absorbent polymers without sacrificing these desired fluid handling properties and without the tendency to gel plug. In fact, the ability to use larger amounts of spherical particles of the hydrogel-forming absorbent polymer offers processing advantages such as more uniform flow rates in the production of these macrostructures.

[0016]

The definition "body fluid" includes urine, menses and vaginal secretions. "Including" means various components, components, steps, etc. that can be used jointly in accordance with the present invention. Therefore,
The term "comprising" encompasses the more restrictive terms "consisting essentially of" and "consisting solely" (of which the latter more restrictive term is a standard as understood in the art) Meaning).

All percentages, ratios and proportions used herein are by weight unless otherwise indicated.

I. A. Porous absorbent macrostructure GENERAL FEATURES The porous absorbent macrostructures of the present invention absorb large amounts of liquids, such as water and / or body exudates (eg, urine or menses) and then remove such liquids from normal A structure that can be held under pressure. Due to the granular nature of the precursor particles, the macrostructure has pores between adjacent precursor particles. These pores are interconnected by interconnecting channels such that the macrostructure is liquid permeable (ie, has a capillary transport channel).

Because of the bonds formed between the precursor particles, the resulting aggregate macrostructure has improved structural integrity, increased liquid capture and distribution rates, and minimal gel occluding properties. When the macrostructure comes into contact with the liquid,
The macrostructures have been found to swell generally isotropically even under moderate confinement pressure, absorbing these liquids into the pores between the precursor particles, and then absorbing these liquids into the particles. The isotropic swelling of the macrostructure allows the precursor particles and pores to still maintain their relative geometry and spatial relationship when swollen. That is, the macrostructure is relatively “fluid-stable” because the precursor particles do not dissociate from each other, thereby minimizing the occurrence of gel blockage and maintaining and expanding the capillary channel upon swelling, and The structure is capable of acquiring and transporting subsequent loads of liquid (even excess liquid).

A "macrostructure" has a substantially circumscribed dry volume (ie, a circumscribed dry volume) of at least about 0.008 mm.
³ , preferably at least about 10.0 mm ³ , more preferably at least about 100 mm ³ , more preferably about 500 mm ³
It means a product having a mm ^3. Typically, the macrostructures of the present invention will have a circumscribed dry volume much greater than about 500 mm ^3. In a preferred embodiment of the invention, the macrostructure has a circumscribed dry volume of about 1000 mm ³
Having to about 100,000mm ^3.

Although the macrostructures of the present invention can have a number of shapes and sizes, macrostructures typically comprise sheets, films, cylinders, blocks, spheres, fibers, filaments, or other materials. It is a form of a shaping element. The macrostructure will generally have a thickness or diameter of about 0.2 mm to about 10.0 mm. Preferably, for use in absorbent products, the macrostructure is
It is in the form of a sheet. The term "sheet" describes a macrostructure having a thickness of at least about 0.2 mm. The sheet will preferably have a thickness of about 0.5 mm to about 10 mm, typically about 1 mm to about 3 mm.

[0022] The porous absorbent macrostructure of the present invention comprises interparticle-bonded aggregates. These interparticle bonded aggregates usually consist of about 8 or more already independent precursor particles. Because of the preferred circumscribed dry volume and size of the individual precursor particles used herein, these interparticle bonded agglomerates typically form from about 100,000 or more individual precursor particles. These individual precursor particles can consist of granules, fines, spheres, flakes, fibers, aggregates or agglomerates. Individual precursor particles may be of various shapes, for example, cubes, rods, polyhedrons, spheres, rounds, squares, irregular, irregular shapes of random size, for example, pulverized material in a pulverization or pulverization step, Alternatively, it may have a shape having a large maximum dimension / minimum dimension ratio, such as a needle shape, a flake shape, or a fiber shape.

The interparticle bonded aggregates that make up the macrostructures of the present invention are formed, in essence, by joining or adhering adjacent particles together. The adhesive is essentially
It is a polymer substance present on the surface of these particles. As these precursor particles are treated with the crosslinker and physically associate, the polymeric material present on the surface of these particles is:
It is sufficiently plastic and cohesive (eg, tacky) that adjacent particles are typically bonded together as discrete bonds between the particles. The adhesive structure is then fixed such that the particles in the aggregate remain cohesively bonded to each other by a cross-linking reaction between the particles.

B. Precursor Absorbable Particles The macrostructures of the present invention are formed from precursor particles comprising a substantially water-insoluble polymeric material capable of absorbing a large amount of liquid. Such polymeric substances are hereinafter referred to as "hydrogel-forming absorbent polymers". The macrostructure of the present invention
These hydrogel-forming absorbent polymer materials are discussed herein with respect to those forming precursor particles, as they consist of interparticle bonded aggregates.

Although the precursor particles can have widely varying sizes, certain particle size distributions and sizes are preferred. For the purposes of the present invention, particle size is determined by sieve size analysis in the case of precursor particles that do not have a large maximum / minimum size ratio, for example, fibers (eg, granules, flakes, or fines). It is defined as the size of the precursor particles to be measured. For the purposes of the present invention, the mass average particle size of the precursor particles is important in determining the properties and properties of the resulting macrostructure. The mass average particle size of a given sample of precursor particles is defined as the average particle size of the sample on a mass basis. The method for measuring the mass average particle size of a sample is described in 1994.
U.S. Pat. No. 5,324,561 issued Jun. 23, 2013 (Rezai et al.) In the Test Methods section. The mass average particle size of the precursor particles is generally from about 20 μm to about 1500 μm, more preferably from about 50 μm to about 1000 μm.
μm. In a preferred embodiment of the present invention, the precursor particles have a weight average particle size of about 1000 μm or less, more preferably about 600 μm or less, and most preferably about 500 μm or less.

A material having large maximum / minimum dimensions,
For example, the particle size of a fiber is typically defined by its largest dimension. For example, if an absorbent polymer fiber (ie, superabsorbent fiber) is used in the macrostructure of the present invention, the length of the fiber is used to define the "particle size" (denier of the fiber). And / or the diameter can also be specified). In an exemplary embodiment of the invention, the fibers have a length of about 5 mm or more, preferably about 10 mm to about 100 mm, more preferably about 10 mm to about 50 mm.

The hydrogel-forming absorbent polymer material that constitutes these precursor particles has a large number of anionic functional groups, for example, sulfonic groups, and more typically carboxy groups. Examples of suitable polymeric materials for use as the precursor particles of the present invention include those formed from polymerizable unsaturated acid-containing monomers. That is, such monomers include olefinically unsaturated acids and anhydrides containing at least one carbon to carbon olefinic double bond. More particularly, these monomers can be selected from olefinically unsaturated carboxylic acids and anhydrides, olefinically unsaturated sulfonic acids and mixtures thereof. See U.S. Pat. No. 5,324,561 issued Jun. 23, 1994 (Rezai et al.), Which generally describes suitable monomers for making hydrogel-forming absorbent polymers.

Preferred polymeric materials for use in the present invention contain carboxy groups. These polymers include a hydrolyzed starch-acrylonitrile graft copolymer, a partially neutralized starch-acrylonitrile graft copolymer, a starch-acrylic acid graft copolymer, a partially neutralized starch-acrylic acid graft copolymer, Vinyl acetate-acrylate copolymers, hydrolyzed acrylonitrile or acrylamide copolymers, slightly crosslinked polymers of any of the foregoing copolymers, partially neutralized polyacrylic acids, and partially neutralized polyacrylics Slightly network crosslinked polymers of acids are included. These polymers can be used either individually or in the form of a mixture of two or more different polymers. For example, U.S. Pat. No. 4,093, issued June 6, 1978, which discloses representative examples of these types of hydrogel-forming absorbent polymers.
No. 776 (Aoki et al.), U.S. Pat. No. 4,666,983 issued May 19, 1987 (Tsubakimoto et al.), And U.S. Pat. No. 4,734,478 issued Mar. 29, 1988. No. (Tsubakimoto et al.).

[0029] More preferred polymeric materials for use in making the precursor particles are slightly network crosslinked polymers of partially neutralized polyacrylic acid and their starch derivatives. Preferably, the precursor particles comprise from about 50% to about 95%, preferably about 75%, of the neutralized slightly network crosslinked polyacrylic acid [i.e., poly (sodium acrylate / acrylic acid)]. Methods for polymer network crosslinking and typical network crosslinking agents are described in the aforementioned US Pat. No. 4,076,66.
No. 3 is described in more detail.

The individual precursor particles can be formed according to a conventional method. For example, precursor particles can be made by methods including aqueous solutions and other solution polymerization techniques. For example, 1988
See U.S. Pat. No. Re. 32,649 (Blunt et al.), Reissued Apr. 19, 1964. Precursor particles useful in the present invention can also be produced using multi-phase polymerization processing techniques such as inverse emulsion polymerization and inverse suspension polymerization. For methods involving inverse suspension polymerization, see, for example, U.S. Pat. No. 4,340,706 issued July 20, 1982 (Obayashi et al.),
US Patent No. 4,506,0, issued March 19, 1985
No. 52 (Flesher et al.) And U.S. Pat. No. 4,735,987 issued Apr. 5, 1988 (Morita et al.). As discussed below, the particular method used in making these precursor particles may be important in determining fluid permeability and capacity characteristics as well as the morphology of the resulting particles.

All of the precursor particles are preferably formed from the same polymeric material having the same properties, but need not be. For example, some precursor particles can consist of a starch-acrylic acid graft copolymer, while
Other precursor particles can consist of a slightly network crosslinked polymer of partially neutralized polyacrylic acid. Further, the precursor particles can vary in size, shape, absorption capacity, or other properties or properties. In a preferred embodiment of the invention, the precursor particles consist essentially of a slightly network crosslinked polymer of partially neutralized polyacrylic acid. Each precursor particle has similar properties.

In a preferred embodiment of the present invention, the precursor particles used to form the bound particle aggregate are substantially dry. "Substantially dry" means that the precursor particles are less than about 50%, preferably less than about 20%, by weight of the precursor particles;
More preferably, it is meant to have a liquid content of about 10% by weight or less, typically water or other solution content. Generally, the liquid content of the precursor particles will range from about 0.01 to about 5% by weight of the precursor particles. The individual precursor particles can be dried by a conventional method such as heating. Alternatively, if the precursor particles are formed using an aqueous reaction mixture, water can be removed from the reaction mixture by azeotropic distillation. The polymer-containing aqueous reaction mixture can also be treated with a dehydrating solvent such as methanol. Combinations of these drying methods can also be used. The dehydrated mass of the polymeric material can then be chopped or milled to form substantially dry precursor particles of the substantially water-insoluble absorbent hydrogel-forming polymeric material.

C. Precursors that provide improved fluid handling
A mixture of particles A key aspect of the present invention is to use a mixture of precursor particles having (1) different fluid handling properties, (2) different shapes, or (3) both. It has been found that mixtures of precursor particles having different fluid handling properties, shapes, or both, can be imparted to macrostructures that provide improved overall fluid handling capacity. This is typically indicated as a combined high fluid permeability / performance and high fluid capacity in the resulting macro mixture made from these mixtures. In fact, macrostructures made from the mixture of precursor particles according to the present invention minimize the potential problem of "gel occlusion" without sacrificing the desired fluid capacity.

The mixture according to the variant (1) of the present invention comprises:
(A) Comparison with a first hydrogel-forming polymer having a relatively high sarin flow conductivity (SFC) value and a relatively high performance under pressure (PUP) capability (for higher gel permeability / performance) And a second hydrogel-forming polymer having an extremely high absorption capacity. Generally, these mixtures consist of about 50 to about 95% higher gel permeability / performance hydrogel forming polymer and about 5 to about 50% higher fluid capacity hydrogel forming polymer. Preferably, these mixtures have from about 60% to about 95% higher gel permeability / performance hydrogel-forming polymer and from about 5% to about 40% higher fluid capacity hydrogel-forming polymer, more preferably, higher gel permeability / performance. From about 60 to about 80% of the high performance hydrogel-forming polymer and from about 20 to about 40% of the higher fluid capacity hydrogel-forming polymer.

Precursor particles useful in the present invention having a relatively high sarin flow conductivity (SFC) value and a relatively high performance under pressure (PUP) capability are disclosed in co-pending US patent application Ser. No. 219,574 (Goldman et al.). These high gel layer permeability / performance precursor particles have an SFC value of at least about 5 × 10 ⁻⁷ cm
³ sec / g, preferably at least about 10 × 10 ⁻⁷ cm ³ sec / g, more preferably at least about 100 × 10 ⁻⁷ cm ³
With seconds / g. Typically, these SFC values range from about 30 × 10 ⁻⁷ cm ³ seconds / g to about 1000 × 10 ⁻⁷ cm ³ seconds / g.
g, more typically about 50 × 10 ⁻⁷ cm ³ s / g to about 50
0 × 10 ⁻⁷ cm ³ s / g, more typically about 100 × 10
In the range of ^-7 cm ³ sec / g to about 350 × 10 ^-7 cm ³ sec / g. These high gel permeability / performance precursor particles generally have a PUP capacity of at least about 23 g / g, preferably at least about 25 g / g, more preferably at least about 2 g / g.
It also has 9 g / g. Typically, these PUP capacity values are in the range of about 23 to about 35 g / g, more typically about 25 to about 33 g / g, and more typically about 29 to about 33 g / g. .

A preferred method for obtaining precursor particles having relatively high SFC and PUP capability values involves surface crosslinking of the initially formed polymer. Numerous methods of introducing surface crosslinking have been disclosed in the art. These include (i)
One or more bi- or polyfunctional reagents (eg, glycerol, 1,3-dioxolan-2-one, capable of reacting with existing functional groups within the hydrogel-forming absorbent polymer)
(Ii) applying polyvalent metal ions, polyquaternary amines) to the surface of the hydrogel-forming absorbent polymer, (ii) reacting with other added reagents and possibly existing functional groups in the hydrogel-forming absorbent polymer. A method of applying to the surface a bi- or multi-functional reagent capable of increasing the amount of cross-linking at the surface (eg addition of monomer plus cross-linking agent and initiation of a second polymerization reaction); (iii) additional multi-functional reagent But one or more additional reactions may be induced between existing components in the hydrogel-forming absorbent polymer during or after the primary polymerization process to generate a high level of crosslinking at or near the surface. Methods (eg, heating and cross-linking agents to induce the formation of anhydride and / or ester cross-links between existing polymer carboxylic acid groups and / or hydroxyl groups are inherently near the surface) Suspension polymerization abundant), and (iv) or to induce a higher level of crosslinking in addition other materials to the surface, a method of reducing the surface deformability of the hydrogel obtained in other ways. Combinations of these surface crosslinking methods, either simultaneously or sequentially, can also be used. In addition to the crosslinkable reagent, other components can be added to the surface to facilitate / control the distribution of crosslinks (eg, spread and penetration of the surface crosslinkable reagent). See co-pending US patent application Ser. No. 219,574 filed Mar. 29, 1999 (Goldman et al.).

A general method suitable for effecting surface crosslinking of the hydrogel-forming absorbent polymer according to the present invention is described in 1985.
U.S. Pat. No. 4,541,871 issued on Sep. 17, 1990 (Obayashi); PCT Application WO 92/16565 published on Oct. 1, 1992 (Stanley); Aug. 9, 1990 Published PCT Application WO 90/08789 (Thailand), published March 31, 1993
Published PCT Application No. WO 93/05080 (Stanley) published on the 8th, US Pat. No. 4,824,901 issued on April 25, 1989 (Alxander), published on January 17, 1989. U.S. Pat.
9,861 specification (Johnson), May 6, 1986
U.S. Pat. No. 4,587,308 (Makita), issued on Mar. 29, 1988, U.S. Pat.
No. 4,478 (Tsubakimoto), U.S. Pat. No. 5,164,459 issued on Nov. 17, 1992 (Kimura et al.), And German Patent Application No. 4, published on Aug. 29, 1991. No. 020,780 (Dahmen) and published European Patent Application 509,708 (Gartner) published October 21, 1992. See also co-pending U.S. Patent Application No. 219,574, filed March 29, 1994 (Goldman et al.), Especially Examples 1-4. Suitable hydrogel-forming absorbent polymers having relatively high SFC and PUP performance values include L76lf from Nippon Shokbay, SXP from Hemiche Fabrik Stockhausen, XZ from Dow Chemical and NZCO from Nalco Chemical. XP-30.

Precursor particles useful in the present invention having relatively high absorption capacity and relatively high absorption (AAP) values are 19
U.S. Pat. No. 4,076,663 issued Feb. 28, 78
No. 32,649 (Blunt et al.), Reissued on Apr. 19, 1988, U.S. Pat.
25,001 (Tsubakimoto et al.), March 1987
U.S. Patent No. 4,666,983 issued on March 19 (Tsubakimoto et al.), U.S. Patent No. 4,734,478 issued March 29, 1988 (Tsubakimoto et al.), 1
US Patent No. 4,735,987 issued April 5, 988
No. 4,973,632 (Nagana et al.), Issued Nov. 27, 1990, and US Pat. No. 5,2,2, issued Nov. 23, 1993.
No. 64,471 (Timeryl) and European Patent Application No. 530,438 (Chambers et al.) Published Mar. 10, 1993, all of which are incorporated. "Absorbing capacity" refers to the ability of a given polymeric material to absorb a contacting fluid and can vary significantly depending on the nature of the fluid to be absorbed and the manner in which the liquid contacts the polymeric material. For the purposes of the present invention, absorption capacity is defined in terms of the amount of synthetic urine absorbed by a given polymer substance, expressed in units of g of synthetic urine / g of polymer substance. See Test Methods section below. The AAP value reflects the required absorbency of the hydrogel-forming polymer, that is, the absorbency of the polymer when subjected to an external pressure of 0.3 psi.
See Test Methods section below. These high fluid capacity precursor particles comprise at least about 25 g of synthetic urine per gram of polymer,
More preferably, it has an absorption capacity value of at least about 35 g, more preferably at least about 45 g. Typically,
These high fluid capacity precursor particles comprise from about 25 to about 70 g of synthetic urine per gram of polymeric material, more typically from about 40 to about 6
It has an absorption capacity value of 0 g.

Preferred methods for obtaining these precursor particles having relatively high absorption capacity include aqueous or other solution polymerization methods. U.S. Pat. No. Re. 32,649.
As described therein, aqueous polymerization involves the use of an aqueous reaction mixture to effect polymerization to form precursor particles. The aqueous reaction mixture is then subjected to polymerization conditions that are sufficient to produce a substantially water-insoluble slightly network crosslinked polymeric material in the mixture. Suitable hydrogel-forming absorbent polymers having relatively high absorption capacity and AAP values include, but are not limited to, IM1000 from Hoechst Celanese, L74 from Nippon Shokubai, and F201 from Nippon Gosei.

The mixture according to the variant (2) of the present invention comprises:
(A) a first hydrogel-forming polymer in the form of spherical particles that can include a spherical aggregate of the first hydrogel-forming polymer (typically produced by a suspension polymerization method); and (b) a bulk polymerization method And a second hydrogel-forming polymer in the form of non-spherical or irregularly shaped particles produced by the method described above. The reason that macrostructures made exclusively from hydrogel-forming absorbent polymer spherical particles are prone to gel occlusion is attributed to the formation of close-packed compacted structures with poorer fluid permeability. Can be It has been found that the incorporation of non-spherical (irregular) particles disrupts the self-assembly properties of the spherical particles during the production of macrostructures, especially sheet-shaped macrostructures. As a result, the macrostructure no longer tends to occlude fluid.

In general, these mixtures according to variant (2) contain about 5 to about 50% of spherical particles and about 50 to 50% of non-spherical particles.
Consists of about 95%. Preferably, these mixtures comprise about 10 to about 50% spherical particles and about 50 to about 9 non-spherical particles.
0%, more preferably about 20 to about 40 spherical particles.
% And about 60 to about 80% non-spherical particles.

The spherical particles and spherical aggregates can be obtained by a multi-phase polymerization processing technique such as an inverse emulsion polymerization method and an inverse suspension polymerization method. In inverse emulsion polymerization or inverse suspension polymerization, the aqueous reaction mixture is suspended in small droplets in a matrix of a water-immiscible inert organic solvent such as cyclohexane. The resulting precursor particles are generally spherical in shape. The reverse suspension polymerization method is described in U.S. Pat. No. 4,093,776 (June 6, 1978) (Aoki et al.),
U.S. Pat. No. 4,340,70 issued Jul. 20, 982
6, U.S. Patent No. 4,446,
No. 261 (Yamasaki et al.); U.S. Pat. No. 4,506,052 issued Mar. 19, 1985 (Fresher et al.); U.S. Pat. No. 4,541,871 issued Sep. 17, 1985. No. (Obayashi etc.), 198
U.S. Pat. No. 4,698,414 issued on Oct. 6, 2007 (Kram et al.), U.S. Pat. No. 4,735,987 issued Apr. 5, 1988 (Morita et al.) 1989.
U.S. Pat. No. 4,833,179 (Young et al.) Issued May 23, 1993 and European Patent Application 522,570 published Jan. 13, 1993. Suitable spherical particles of the hydrogel-forming absorbent polymer include F201 from Nippon Gosei and Base 60 from Mitsubishi Chemical.

Non-spherical or irregularly shaped particles can be obtained by bulk polymerization methods, including aqueous or other solution polymerization methods. U.S. Reissue Patent No. 32,6
As described in US Pat. No. 49, aqueous solution polymerization involves conducting a polymerization using an aqueous reaction mixture to form precursor particles. The aqueous reaction mixture is then
Subject to polymerization conditions that are sufficient to produce a substantially water-insoluble slightly network crosslinked polymeric material. The resulting mass of polymer material is then comminuted or chopped to form individual precursor particles. Suitable non-spherical particles of the hydrogel-forming absorbent polymer include L76lf from Nippon Shokubai, SXP or SXM from Hemische Fabrik Stockhausen, and Narco.
Chemical 1180 or XP30.

D. Crosslinking agent When producing the macrostructure according to the present invention, the crosslinking agent,
Used to provide crosslinking at the surface of the mixture of absorbent precursor particles. This typically results from reacting the crosslinking agent with the polymeric material in these particles. Typically, the polymeric material of the absorbent precursor particles has an anionic function, preferably a carboxy function, that forms a covalent ester type bond with the crosslinker. These portions of the effectively crosslinked absorbent particles will not swell much in the presence of an aqueous fluid (body fluid) compared to other non-crosslinked portions of the particles.

Suitable crosslinkers for this purpose can be nonionic compounds and have at least two functional groups which can react with carboxy groups per molecule. For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerol (1, 2,
3-propanetriol), polyglycerol, propylene glycol, 1,2-propanediol, 1,3-
Polyhydric alcohols such as propanediol, trimethylolpropane, diethanolamine, triethanolamine, polyoxypropylene, oxyethylene-oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, pentaerythritol and sorbitol; ethylene glycol Diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitol polyglycidyl ether, pentaerythritol polyglycidyl ether, propylene glycol diglycidyl ether, propylene glycol diglycidyl ether, etc. Polyglycidyl A Le compounds; 2,2-bis-hydroxymethyl butanol - tris [3- (i - aziridine)
Propionate], 1,6-hexanemethyltoluene diethylene urea, diphenylmethane-bis-4,4'-
Polyaziridine compounds such as N, N'-diethylene urea; haloepoxy compounds such as epichlorohydrin and α-methylfluorohydrin; polyaldehyde compounds such as glutaraldehyde and glyoxazole; ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylene 1992 discloses various nonionic crosslinking agents including polyamine compounds such as pentamine, pentaethylenehexamine, and polyetheneimine; and polyisocyanate compounds such as 2,4-toluene diisocyanate and hexamethylene diisocyanate.
See U.S. Pat. No. 5,102,597 issued Apr. 7, 1998 (Loe et al.). A particularly preferred non-ionic crosslinker is glycerol.

Preferred crosslinking agents for use in the present invention are
An adduct of epichlorohydrin with certain types of monomeric or polymeric amines. 1994 6 discloses suitable cationic amino-epichlorohydrin adduct crosslinkers
See U.S. Pat. No. 5,324,561 issued May 23 (Rezai et al.). These amino-epichlorohydrin adducts, and in particular the polymeric resin versions of these adducts, are preferred crosslinkers because they only react with the polymeric material at the surface precursor particles. In addition, these adducts, especially the cationic functional groups (azetedinium groups) of the polymeric resin version, are capable of absorbing the anionic functional groups of the polymeric material of the absorbent particles, even at room temperature (eg, about 18 to about 25 ° C.). Would typically react very quickly with the carboxy function.
As a result, significantly modest amounts (eg, as little as about 1% by weight of the particles) of these amino-epichlorohydrin adducts result in efficient surface crosslinking of the polymeric material present in the absorbent precursor particles. Needed to give.

Suitable cationic amino-epichlorohydrin adducts useful as cross-linking agents include epichlorohydrin having monomeric di-, tri- And higher amines such as bis-2
-Aminoethyl ether, N, N-dimethylethylenediamine, piperazine, ethylenediamine, N-aminoethylpiperazine, and dialkylenetriamines, such as diethylenetriamine and dipropylenetriamine, polymeric amines, such as polyethyleneimine and polyalkylenepolyamine and saturated C ₃ -C ₁₀ dibasic certain polyamides derived from a carboxylic acid - include those reacted with a polyamine. These epichlorohydrin / polyamide-polyamine adducts are known in the art as wet strength resins for paper products. More preferred epichlorohydrin / polyamide-polyamine adducts are polyethylene polyamines containing 2 to 4 ethylene groups, 2 primary amine groups and 1 to 3 secondary amine groups and saturated aliphatic C ₃ -C ₁₀ dicarboxylic acid, more preferably those having 3 to 8 carbon atoms, for example, malonic acid,
It is derived from succinic acid, glutaric acid, adipic acid (along with diglycolic acid). Cationic polyamide-polyamine-epichlorohydrin resins, which are particularly preferred here as crosslinkers, are marketed by Hercules Incorporated under the tradename Kimen. Kimene 557H, 557LX and 557 which are epichlorohydrin adducts of polyamide-polyamine which is a reaction product of diethylenetriamine and adipic acid.
PLUS is particularly useful. They are typically
It is commercially available in the form of an aqueous solution of a cationic resin material containing from about 10 to about 33% by weight of the resin active ingredient.

E. Interparticle bonded aggregates and macrostructures
During the production of the interparticle-bonded aggregates constituting the porous absorbent macrostructure, the mixture of absorbent precursor particles causes effective cross-linking, that is, the cross-linked surface of the particles is in the presence of an aqueous body fluid. The particles are treated with a sufficient amount of a cross-linking agent to react with the polymeric material at the surface of the particles such that there is less swelling compared to the non-cross-linked portions below. What constitutes a "sufficient amount" of crosslinking is the particular absorbent precursor particles to be treated, the crosslinking agent used,
It depends on a number of factors, including the particular effect desired in forming the interparticle bonded aggregates and similar factors. 199
U.S. Pat. No. 5,102,597 (Loe et al.) (Non-ionic cross-linking agent such as glycerol) issued on Apr. 7, 2002; and U.S. Pat. No. 5,324,561 issued on Jun. 23, 1994. (Resai et al.) (Cationic amino-epichlorohydrin adduct crosslinking agent).

In addition to the absorbent precursor particles and the cross-linking agent, other components or agents can be used as auxiliaries in making interparticle bonded aggregates. For example, water is typically used in combination with a crosslinking agent to prepare the aqueous treatment liquid. Water promotes uniform dispersion of the cross-linking agent on the surface of the precursor particles and causes penetration of the cross-linking agent into the surface area of these particles. Water also promotes a stronger physical association between the treated precursor particles, providing greater integrity of the resulting interparticle-linked cross-linked aggregates. The actual amount of water used depends on the type of crosslinking agent used, the type of polymeric material used to form the precursor particles, the particle size of these precursor particles, the blending of other optional components (eg, glycerol) and It can be varied according to similar factors. U.S. Pat. No. 5,102,597 issued on April 7, 1992 (Loe et al.) (A nonionic cross-linking agent such as glycerol); and U.S. Pat. No. 5,324,561 issued June 23, 1994. (Resai et al.) (Cationic amino-epichlorohydrin adduct crosslinking agent).

Although it is not absolutely necessary,
Organic solvents can usually be used to promote uniform distribution of the cross-linking agent precursor particles on the surface. These organic solvents are typically hydrophilic and include lower alcohols such as methanol, ethanol, and the like;
Examples include amides such as N, N-dimethylformamide and N, N-diethylformamide; and sulfoxides such as dimethylsulfoxide. The actual amount of hydrophilic solvent used can vary depending on the adduct used, the polymeric material used to form the precursor particles, the particle size of these precursor particles, and similar factors. 1992 4
U.S. Pat. No. 5,102,597 (Loe et al.) (Non-ionic cross-linking agent such as glycerol) and U.S. Pat.
No. 4,561 (Rezai et al.) (Cationic amino-epichlorohydrin adduct crosslinking agent).

Other optional components can be used in combination with the crosslinking agent, especially the aqueous treating solution. It is particularly preferred that the treatment liquid includes a plasticizer, especially when a cationic amino-epichlorohydrin adduct is used as a crosslinking agent. June 23, 1994
See U.S. Pat. No. 5,324,561 issued to Japan (Rezai et al.). Suitable plasticizers include, alone or with other components, such as glycerol, propylene glycol (i.e., 1,2-propanediol), 1,3-propanediol, ethylene glycol, sorbitol, sucrose, polymer solutions such as, for example, Water in combination with polyvinyl alcohol, ester precursors of polyvinyl alcohol, or polyethylene glycol or mixtures thereof. These other components in the plasticizer, such as glycerol, are believed to act as humectants, supplemental plasticizers or both, and water is the primary plasticizer. Preferred plasticizers for use in the present invention, particularly when formulated as part of an aqueous treatment solution of a cationic amino-epichlorohydrin adduct, have a weight ratio of glycerol to water of about 0.1.
5: 1 to about 2: 1, preferably about 0.8: 1 to about 1.7: 1 mixture of glycerol and water.

The actual amount of plasticizer used will vary depending on the particular plasticizer used, the type of polymeric material used in forming the precursor particles, and the particular flexibility effect desired from the plasticizer. it can. Typically, the plasticizer comprises precursor particles 10
About 5 to about 100 parts by weight, preferably about 5
To about 60 parts by weight, more preferably about 10 to about 30 parts by weight, more preferably about 15 to about 20 parts by weight. US Patent No. 5,32, issued June 23, 1994
No. 4,561 (Rezai et al.).

In the method of the present invention, the absorbent precursor particles can be treated with a cationic amino-epichlorohydrin adduct, typically a solution thereof, by any of a variety of techniques. These include a method of coating the absorbent precursor particles with a cationic amino-epichlorohydrin adduct or a solution thereof, a method of dumping, a method of pouring, a method of dropping, a method of spraying, a method of atomizing, and a method of condensing. Or any method of applying the solution to the material, including immersion. "Apply" means that at least a portion of at least some surface area of the precursor particles to be bonded together has an effective amount of adduct thereon to effect surface cross-linking. In other words, the cation adduct is
It can be applied on some of the precursor particles, on all of the precursor particles, on a portion of the surface of some or all of the precursor particles, or on some or all of the entire surface of the precursor particles. Preferably,
The adduct is predominantly of the absorbent precursor particles to enhance the efficiency, strength and density of interparticle bonding between the precursor particles and the desired surface crosslinking of the polymeric material in the surface of these precursor particles,
Preferably it is coated on all surfaces.

After applying the treatment liquid onto the precursor particles, the treated precursor particles are combined together by any of a number of mixing or layering techniques to ensure that the precursor particles are sufficiently coated with the treatment liquid. Can be mixed or layered. 1992
U.S. Pat. No. 5,102,597 (Loe et al.) (A nonionic cross-linking agent such as glycerol) issued on Apr. 7, 2014;
And U.S. Patent No. 5,32, issued June 23, 1994.
No. 4,561 (Rezai et al.) (Cationic amino-epichlorohydrin adduct crosslinking agent). Before applying the processing solution,
At or after application, the precursor particles physically associate together to form aggregate macrostructures. The precursor particles are preferably physically associated with each other by applying the associative agent onto the precursor particles and physically contacting the precursor particles with at least a portion of the surface of the precursor particles to which the associative agent has been applied. As an associative agent useful in the present invention, a hydrophilic organic solvent,
Typically low molecular weight alcohols such as methanol and ethanol; water; a mixture of a hydrophilic organic solvent and water; a crosslinking agent;
Or mixtures thereof. Preferred associating agents are water, methanol, ethanol, cationic polymeric amino-epichlorohydrin resins, for example, Kimene 557H.
Or 557LX or PLUS, or a mixture thereof. Typically, the associative agent comprises a mixture that includes the crosslinker such that the step of applying the crosslinker is performed simultaneously with the step of applying the associative agent.

The associating agent may be formed by coating the associating agent on the precursor particles, damping, pouring, spraying,
The precursor particles can be applied by any of the various techniques and equipment used to apply a solution to a substance, including by atomizing, condensing, or immersing.
U.S. Patent No. 5,102,59 issued April 7, 1992
No. 7 (Loe et al.) (A nonionic crosslinking agent such as glycerol) and U.S. Pat. No. 5,324,561 issued June 23, 1994 (Rezai et al.) (Cationic amino-epichlorohydride) Phosphorus adduct crosslinking agent). When the associative agent is applied to the precursor particles, the precursor particles can physically contact together in a number of different ways. For example, the associative agent alone can hold the particles together in contact. Alternatively, gravity can be used to ensure contact between the precursor particles, for example, by layering the precursor particles. Further, the particles can be placed in a container having a fixed volume to ensure contact between the precursor particles.

The precursor particles can alternatively be physically associated together by physically constraining the precursor particles so that they come into contact with each other. For example, the precursor particles can be tightly packed in a container having a fixed volume such that the precursor particles are in physical contact with each other. Alternatively, or in combination with the above method, gravity (eg, layering) can be used to physically associate the precursor particles. Also, the precursor particles can be physically associated together by electrostatic attraction or by the introduction of an adhesive (eg, an adhesive such as a water-soluble adhesive) to adhere them together. The precursor particles are
The precursor particles can be bonded to a third member (substrate) such that they are brought into contact with each other by the substrate.

In another method of forming the macrostructure of the present invention, the agglomerates of precursor particles are shaped into a variety of geometric shapes, spatial relationships and densities to define a defined shape, size and / or density. Form aggregates with density. Agglomerates can be shaped by conventional shaping techniques known in the art. Preferred methods for shaping the agglomerates include casting, molding, or molding operations. Casting and molding techniques generally involve introducing precursor particles into a manufactured mold cavity and applying pressure (compression) to the agglomerate to bring the agglomerate into the shape of the mold cavity. I do. Examples of particular molding techniques for use herein include compression molding, injection molding, extrusion or lamination. For example, a number of precursor particles can be added to a container having a fixed volume of the mold cavity, and then compressed such that the macrostructure from which the agglomerate is obtained has the same shape, to the same shape as the mold cavity. Molding techniques involve performing various operations on the agglomerates to modify their shape, and / or size and / or density. Examples of specific forming techniques for use herein include rolling, forging, extruding, spinning, coating or drawing operations. For example, an aggregate mixture of precursor particles and at least one cationic amino-epichlorohydrin can pass between a pair of compacting rolls to form an aggregate sheet. Alternatively, the aggregate mixture can be extruded through an orifice to form an aggregate having a shape corresponding to the shape of the orifice. Further, the aggregate mixture can be cast onto a surface to form an aggregate having a desired shape or surface morphology. Any or all of these techniques can also be used in combination to form shaped aggregates. Any suitable device known in the art can be used to perform such an operation, the operation being hot and / or
Alternatively, it can be accomplished using materials or parts of the device, either cold. A preferred method and apparatus for continuously forming the aggregate macrostructures of the present invention into sheets is:
U.S. Patent No. 5,324,5, issued June 23, 1994
No. 61 (Rezai et al.) (Cationic amino-epichlorohydrin adduct crosslinking agent). See especially FIG. 9 and the accompanying description from US Pat. No. 5,324,561.

Simultaneously with or after the application of the treatment liquid, the precursor particles are physically associated with each other to form aggregates and form the aggregates, the crosslinking agent is maintained while maintaining the physical association of the precursor particles. React with the polymeric material of the precursor particles to provide effective surface crosslinking in the precursor particles in the aggregate macrostructure. U.S. Patent No. 5,102, issued April 7, 1992
597 (Loe et al.) (A nonionic cross-linking agent such as glycerol) and U.S. Patent No. 5,324,561 issued June 23, 1994 (Rezai et al.) (Cationic amino-epichlorohydride Phosphorus adduct crosslinking agent). Due to the relatively reactive cationic functionality of the amino-epichlorohydrin adduct that can be used as a crosslinking agent in the present invention, this crosslinking reaction can be performed at relatively low temperatures, including ambient room temperature. Such room temperature curing is particularly desirable when the treatment liquid additionally contains a plasticizer, for example, a mixture of water and glycerol. Curing at temperatures significantly higher than room temperature drives out the plasticizer due to volatility and may require additional steps to plasticize the interparticle bonded aggregates thus obtained. Such room temperature curing typically occurs at a temperature of about 18 to about 35 ° C. for about 12 to about 48 hours. Preferably, such room temperature curing is from about 18 to about 2
Perform at a temperature of 5 ° C. for about 24 to about 48 hours.

The crosslinking reaction can be performed at room temperature, but such curing can also be performed at elevated temperatures to accelerate the reaction. High temperature curing typically involves heating the treated and associated precursor particles to cause a crosslinking reaction to occur in a short time, typically in minutes. This heating step can be performed using a number of conventional heating devices, including various ovens or dryers known in the art.

Generally, heat curing can be performed at a temperature of about 50 ° C. or higher for a time sufficient to complete the crosslinking reaction. The particular temperature and time used in heat curing will depend on the particular crosslinker used and the polymeric material present in the precursor particles. U.S. Pat. No. 5,102,597 issued on Apr. 7, 1992 (Loe et al.) (A nonionic cross-linking agent such as glycerol), and Jun. 2, 1994
See U.S. Pat. No. 5,324,561 issued on March 3 (Rezai et al.) (Cationic amino-epichlorohydrin adduct crosslinking agent). For the preferred cationic amino-epichlorohydrin adduct, heat curing is generally about 50
Performed at a temperature of about to about 205C for about 1 to about 20 minutes. Preferably, the heat cure is performed at a temperature of about 180 to about 200 ° C. for about 5 to about 5 hours.
Perform for about 15 minutes.

The physical association of the treated precursor particles needs to be maintained during the curing step so that adjacent precursor particles are coherently bonded together when crosslinking occurs. If the force or stress is sufficient to dissociate the precursor particles present during the crosslinking reaction, insufficient bonding of the precursor particles may occur. This can result in aggregates having poor structural integrity. The physical association of the precursor particles is typically maintained by ensuring that a minimum dissociation force or stress is introduced during the curing step.

The steps for fabricating the macrostructure do not need to be performed in any particular order and can be performed simultaneously. For example, the treatment liquid may be applied simultaneously with the physical association of the precursor particles and shaped into a preferred shape and typically the desired density, and then the crosslinking agent may be left immediately after completing the process or leaving the aggregates for a predetermined time. After one of them,
The precursor particles can be reacted with the polymeric material to simultaneously surface cross-link the precursor particles and form an aggregate macrostructure. Typically, the precursor particles are mixed or sprayed with a solution of a crosslinking agent and water and a humectant and / or a supplemental plasticizer (eg, glycerol) and a hydrophilic organic solvent (eg, methanol) to adhere to each other. To form aggregates. Thereafter, the agglomerated aggregates (ie, the associated precursor particles and the aqueous mixture)
Is formed into a densified sheet by a combination of the extrusion technique and the rolling technique as described above. Thereafter, the crosslinking agent is reacted with the polymeric material by room temperature curing or heat curing to form cross-linking at the surface of the precursor particles and at the same time to form an inter-agglomerated bonded aggregate macrostructure.

The macrostructure can also be treated with a plasticizer after curing to make the surface cross-linking effective. Suitable plasticizers include water alone or in combination with the humectant / auxiliary plasticizer, preferably glycerol. Plasticizer is a method of spraying a plasticizer onto a macrostructure, a method of coating, a method of atomizing, a method of dipping,
Or it can be applied to the macrostructure in a number of different ways, including damping. Alternatively, in the case of water alone, the macrostructure can be placed in a high humidity environment (eg, a relative humidity greater than 70%). The amount of plasticizer applied to the macrostructure can be chosen depending on the particular plasticizer used and the effect desired. Typically,
The application amount of the plasticizer is about 5 to about 100 parts by weight, preferably about 5 to about 60 parts by weight, per 100 parts by weight of the macrostructure. Particularly preferred plasticizers are from about 0.5: 1 to about 2:
1, preferably a mixture of glycerol and water in a weight ratio of about 0.8: 1 to about 1.7: 1.

Various fiber materials can be used as reinforcing members in the macrostructure of the present invention. Any type of fibrous material that is suitable for use in conventional absorbent products is also suitable for use in the macrostructure of the present invention. Specific examples of such fiber materials include cellulose fibers, modified cellulose fibers, rayon, polypropylene, and polyester fibers such as polyethylene terephthalate [DACRON], hydrophilic nylon [HYDROFIL], and the like. . Examples of other fiber materials for use in the present invention, in addition to some of the foregoing, include hydrophilized hydrophobic fibers, for example, polyolefins such as polyethylene, polypropylene, polyacryl, polyamide, polystyrene, polyurethane, and the like. Derived surfactant- or silica-treated thermoplastic fibers. In fact, hydrophobized hydrophobic fibers that are not themselves and by themselves less absorbent and therefore do not provide a web of sufficient absorption capacity to be useful in conventional absorbent structures are:
It is suitable for use in the macrostructure of the present invention due to its good wicking properties. This is because, in the macrostructure of the present invention, the wicking tendency of the fibers is less important than the absorption capacity of the fibrous material itself due to the high fluid uptake rate and lack of gel occlusiveness of the macrostructures of the present invention. Is equally important. Synthetic fibers are generally preferred for use herein as the fiber component of the macrostructure.
Polyolefin fibers, preferably polyethylene fibers, are more preferred.

Another cellulosic fiber material that may be useful in certain macrostructures of the present invention is chemically stiffened cellulosic fibers. Preferred chemically stiffened cellulosic fibers are stiffened twisted curled cellulosic fibers that can be produced by internally cross-linking the cellulose fibers with a cross-linking agent. Suitable stiffened twisted curled cellulose fibers useful as the hydrophilic fiber material of the present invention are described in U.S. Patent No. 4,888,093, issued December 19, 1989 (Dean et al.), December 1989. US Patent No. 4, issued on 26th
889,595 (Heron et al.), December 1989
U.S. Pat. No. 4,889,596 (Schoggen et al.) Issued on Dec. 26, 1989, U.S. Pat. U.S. Pat. No. 4,898,
No. 647 (Moore et al.) Are described in great detail.

"Hydrophilic" describes a fiber or the surface of a fiber that is wetted by a liquid deposited on the fiber (ie, water or water, regardless of whether the fiber actually absorbs fluid or forms a gel). (If the aqueous body fluid spreads easily on or beyond the surface of the fibers). The state of the art with respect to material wetting allows the definition of hydrophobicity (and wetting) by the contact angle and surface tension of the involved liquids and solids. This is based on the publication of the American Chemical Society's “Contact Angle, Wettability, and
Adhesion "(edited by Robert F. Gould, 1964)
Copyright). The fiber or fiber surface has a contact angle between the liquid and the fiber or surface of 90 °
It is said to be wet by the liquid when it is less than or when the liquid will tend to spontaneously spread across the surface of the fiber. Both conditions usually coexist.

The fibrous material can be macrostructured by introducing the fibers into the processing liquid together with a cross-linking agent, by mixing with the precursor particles before applying the processing liquid, or by adding the fiber material to the processing liquid / precursor particle mixture. Can be added to the product. For example, the fibrous material can be kneaded with the treatment liquid / precursor particle mixture. The fibrous material is preferably mixed well with the solution such that the fibrous material is evenly dispersed throughout the macrostructure. Also, the fibers are preferably added prior to the reaction of the adduct with the polymeric material of the precursor particles.

F. Optional Substrate Layer The porous absorbent macrostructure can be bonded to any substrate, as desired. See co-pending US patent application Ser. No. 142,253, issued Oct. 22, 1993 (Shue et al.). The substrate may be provided with a macrostructure by (1) improving the distribution of fluid to be absorbed by the macrostructure, and (2) providing additional integrity, especially in situations where the absorbent particles begin to swell after fluid absorption. Various functions can be provided, including supporting Substrates can be made of various materials known in the art, for example, cellulosic fibers, nonwoven webs,
Tissue web, foam, polyacrylate fiber,
It can be made from apertured polymeric webs, synthetic fibers, metal foils, elastomers, and the like. Most such substrate materials are capable of distributing fluid to the macrostructure as well as supporting the macrostructure. Preferably, the substrate comprises a cellulosic material or a material having cellulosic functionality. Preferred substrates for fluid distribution are cellulosic materials, fibrous webs, cellulosic fibrous webs, solid foams, cellulosic foams, and polyvinyl alcohol foams. Preferred substrates for supporting the macrostructure are cellulosic materials, fibrous webs, nonwoven webs, fabrics, cellulosic fibrous webs, solid foams, cellulosic foams, and polyvinyl alcohol foams.

The substrate is preferably flexible and flexible, which facilitates such properties with the resulting absorbent composite having macrostructures. The substrate may be substantially elastic and non-extensible, or may be extensible or deformable to varying degrees in response to forces applied perpendicular to and in the plane of the surface of the substrate. Can be possible. The thickness and basis weight (weight per unit area of the substrate) of the substrate material can vary depending on the type of substrate and the properties desired. The substrate can consist of multiple individual sheets or plies of a particular substrate material, or a combination of one or more substrate layers in a laminate. One such suitable substrate has a thickness of about 0.02 mm to about 1.2 m.
m, more preferably from about 0.3mm~ about 0.8 mm, and a basis weight of about 5 g / m ² ~ about 100 g / m ^2, more preferably from about 10 g / m ² ~ about 60 g / m ^2, more preferably about 15
g / m ² to about 40 g / m ² (BOUN
TY ^R ) Sheet. Another suitable substrate has a dry compaction thickness of about 0.5 mm to about 3.0 mm, more preferably about 0.8 mm to about 3.0 mm.
About 2.0 mm, wet expansion thickness about 0.8 mm to about 6.0 mm, more preferably about 1.0 mm to about 5.0 mm, and a basis weight of about 5
0 g / m ² ~ about 2,000 g / m ^2, more preferably a cellulose foam having about 100 g / m ² ~ about 1,000 g / m ^2.

Substrates suitable for supporting macrostructures typically have a dry tensile strength of about 500 g / in to about 8,000 g / in, more preferably about 1,000 g / in.
/ Inch to about 3,000 g / inch, wet tensile strength of about 2
00 g / inch to about 5,000 g / inch, more preferably about 400 g / inch to about 1,000 g / inch, and a wet burst strength of about 100 g to about 2,000 g, more preferably about 200 g to about 1,000 g. Have. Preferred substrates of this type include cellulosic fibrous webs,
For example, paper towels and tissues, for example, 1
U.S. Patent No. 3,953,63, issued April 27, 976
8, U.S. Patent No. 4, issued September 4, 1984;
No. 469,735, U.S. Pat. Nos. 4,468,428, issued Aug. 28, 1984 and 1991.
No. 4,986,882, issued Jan. 22, 1998. Another preferred substrate layer of this type is a cellulosic foam. The reason is,
It provides a higher fluid wicking speed than the cellulosic fibrous web over long wicking distances. Preferably, the cellulosic foam is in a compressed state to further improve fluid wicking and distribution. Suitable cellulosic foams are known in the art, e.g.
It can be made from recycled rayon fibres, as disclosed in European Patent Application No. 293,208 published Jan. 30 (Uchida et al.).

The porous absorbent macrostructure can be bonded to the substrate by various chemical, physical, and adhesive agents. Adhesives for bonding the substrate to the macrostructure include glues and hot melt adhesives. Preferably, the bond between the substrate and the macrostructure comprises depositing the precursor particles on the substrate, treating the deposited particles with a solution comprising a crosslinker, and then treating the treated particles / substrate as described above. It is achieved by hardening. In a preferred embodiment of the present invention, a cellulosic substrate (eg, paper towel) is used. Next, the pre-absorbent particles adhere to the cellulosic substrate. A treatment solution comprising an amino-epichlorohydrin adduct, preferably a polymeric epichlorohydrin-polyamide / polyamine wet strength resin such as chimene, is applied (eg, sprayed) onto a cellulosic substrate and an absorbent. The treated substrate / particle is then cured at room temperature to form a porous macrostructure bonded to the cellulosic substrate.

G. Latex to improve flexibility
In some cases, the absorbent macrostructure (with or without optional substrate) can be treated with a particular latex. "Latex" means an aqueous dispersion or emulsion of polymer particles in an aqueous phase and may also be referred to as an emulsion polymer. "Sinter" means the melting mechanism that occurs upon drying of a suspension emulsion or dispersion, such as latex.
The use of "sinter" is synonymous with the phrase "film formation." Treatment of these macrostructures with these latexes has been found to dramatically increase the flexibility of the macrostructures, especially when in sheet form and even when bonded to a substrate such as a paper towel. . In addition to the improved flexibility, the latex treatment according to the invention improves the bonding between the particles of the aggregates constituting these macrostructures. This results in improved dry and wet integrity of the macrostructure. The presence of the latex also allows these macrostructures to be thermally bonded to a nonwoven, such as a backsheet of an absorbent article (eg, a diaper).

It has been found that latexes suitable for use in the present invention need to have certain properties. One key property of these latexes is that they are "rubbery" below room temperature after sintering. In other words, latexes useful in the present invention have a glass transition temperature (T
_g ) having a temperature of about 25 ° C. or less. Preferably, these latexes have a T _{g of} about 10 ° C. or less, more preferably about −10 ° C.
C. or less. Another important property of these latexes is the temperature at which they can be sintered. Latexes useful in the present invention must be capable of sintering below room temperature. In other words, these latexes are preferably sinterable at temperatures up to about 25 ° C. The ability of the latex to be sinterable at room temperature is important in avoiding complete drying of the macrostructure. Another important property of these latexes is hydrophilic. To be useful in the present invention, the latex must be at least slightly hydrophilic upon sintering. "Hydrophilic"
Is an aqueous fluid (eg, aqueous body fluid) deposited on a substance
Means the surface of a substance or substance that can be wetted by. Hydrophilicity and wettability are typically defined by the contact angle and surface tension of the contained fluid with the solid. This is because of the American Chemical Society's publication Contact Angle, Wettability and Adhesion
, Robert F. Gold Edition (copyright in 1964)
Are discussed in detail.

Latexes useful in the present invention are typically prepared by emulsion polymerization of certain olefin (ethylenically unsaturated) monomers. The emulsion polymerization includes alkyl sulfates, alkyl aryl alkoxy sulfates, alkyl aryl sulfonates and alkali metal and / or ammonium salts of alkyl polyglycol ether sulfates and alkyl aryl polyglycol ether sulfates; oxyethylated fatty alcohols or oxyethylated alkyl phenols,
And a block copolymer of ethylene oxide and propylene oxide; a cation adduct of a primary, secondary or tertiary fatty amine or fatty amine oxyethylate with an organic or inorganic acid, and a quaternary alkyl ammonium interface Activator; and stable latex obtained by using any of various anionic emulsifiers, nonionic emulsifiers, cationic emulsifiers, zwitter emulsifiers and / or amphoteric emulsifiers, including alkylamidopropyl betaine, in a conventional manner. Can be The olefin monomer can be a single type of monomer or a mixture of different olefin monomers, i.e., can form copolymer particles dispersed or emulsified in an aqueous phase. . Latexes suitable for use herein are preferably neutral or have no ionic charge, whereas latexes are not cationic or anionic in nature.

Suitable latexes are C ₂ -C ₄ alkyl acrylates and hydroxyalkyl acrylates,
For example, propyl acrylate, n-butyl acrylate,
It can be prepared by emulsion polymerization from olefin monomers including those selected from the group of isobutyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, ethyl acrylate and mixtures thereof. Propyl methacrylate, n-butyl methacrylate,
Isobutyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, ethyl methacrylate, methyl methacrylate, C ₁ -C ₄ alkyl methacrylates or hydroxyalkyl methacrylates are selected from the group consisting of vinyl acetate, and mixtures thereof are also It is suitable. Mixtures of the aforementioned C ₂ -C ₄ alkyl acrylates or hydroxyalkyl acrylates with C ₁ -C ₄ alkyl methacrylates or hydroxyalkyl methacrylates are also suitable. Emulsions of polymethyl methacrylate are particularly preferred for use in the present invention. Particularly preferred latex is MONWINYL 963 by Hoechst Celanese.
And those sold by Rohm & End Haas under the trade name RHOPLEX E1845.

In making the porous absorbent macrostructure of the present invention with improved flexibility, the macrostructure comprises:
Treatment with an effective amount of these latexes covers at least some of the absorbent particles. What constitutes an "effective amount" depends on a variety of factors, including the particular porous absorbent macrostructure involved, the particular latex used, the desired flexibility benefit, and similar factors. Will do.
More preferably, treating the macrostructure with about 2% by weight latex will be sufficient to provide an improvement in the flexibility of the macrostructure. However, the macrostructure can be effectively treated with about 1 to about 10% by weight of the latex, more preferably about 2 to about 5% by weight.

The porous absorbent macrostructure can be treated with the latex by any of a variety of methods suitable for applying an adhesive to a conventional substrate. The preferred method is
Spraying, printing (eg, flexographic printing), coating,
For example, a gravure coating method, a dipping method, a brushing method, a foaming method, or a combination of such application techniques may be used. Typically, the latex is sprayed onto the already formed porous absorbent macrostructure and then sintered at room temperature, for example, at or below about 25 ° C. Additionally, latex treatment can help form more stable macrostructures by providing improved particle immobilization.

In addition to spraying on the latex onto the already formed macrostructure, other methods can also be used to treat the porous absorbent macrostructure with the latex. One such method involves blending the latex with untreated pre-absorbent particles and then treating the latex / particle blend with a solution containing a cross-linking agent and other optional ingredients such as glyceryl. . Then
The treated latex / particle blend can be cured at room temperature, for example, at or below about 25 ° C., to provide a porous absorbent macrostructure with improved flexibility.

Another method involves casting the latex as a thin film. The pre-absorbent particles can then be deposited on the casting film. The cast film with the attached particles is then treated (eg, by spraying) with a solution containing a cross-linking agent and other optional components. The treated particle / latex film can then be cured at room temperature, for example, at or below about 25 ° C., to provide a porous absorbent macrostructure with improved flexibility. In addition, the sintered latex film can function as a support for the macrostructure to provide dry integrity and especially wet integrity.

Yet another method involves pressing the latex in a container so that the latex can be blown or sprayed onto the precursor particles in the form of a foam, and then uniformly spreading the latex using a compression roll or the like. I do. Blown or spray foam latex is, to some extent, very porous and in the form of porous fibers that further enhance the absorbency of the macrostructure. This type of latex-treated macrostructure (where the precursor particles swell into the porous latex fibers)
Has improved structural integrity.

III. Uses of Macrostructures The porous absorbent macrostructures of the present invention can be used for many purposes in many fields of use. For example, macrostructures include packaging containers; drug delivery devices; wound cleaning devices;
Burn treatment devices; Ion exchange column materials; Construction materials; Agricultural or horticultural materials, such as seed sheets or water retention materials; Can be used for control material.

Because of the unique absorbency of the porous absorbent macrostructure of the present invention, the macrostructure is particularly suitable for use as an absorbent core in absorbent articles, especially disposable absorbent articles. "Absorptive article" means an article that absorbs and contains body exudates, and more particularly, absorbs various exudates excreted from the body by placing it on or near the wearer's body. And containable items. Additionally, a "disposable absorbent article" is intended to be disposed of after a single use (i.e., some or all of the absorbent article may be recycled, reused, or composted). However, the original absorbent article is not intended to be washed as a whole, otherwise restored, or reused as an absorbent article). A preferred embodiment of the disposable absorbent article, the diaper 20, is shown in FIG. "Diaper" means a garment (generally worn by infants and incontinents) that is worn around the wearer's lower torso. However, it should be understood that the present invention can be applied to other absorbent articles, such as incontinence briefs, incontinence pads, training pants, diaper inserts, sanitary napkins, decorative paper, paper towels, and the like.

FIG. 3 is a perspective view of the diaper 20 of the present invention in an uncontracted state (ie, removing all elastically induced contractions). Then, a portion of the structure is cut away to clearly show the structure of the diaper 20, and a portion of the diaper 20 that comes into contact with the wearer faces the observer. Diaper 20
Preferably, a liquid-permeable topsheet 38; a liquid-impermeable backsheet 40 joined to the topsheet 38; an absorbent core 42 disposed between the topsheet 38 and the backsheet 40; an elastic member 44; The provision of a tab fastener 46 is shown in FIG. The topsheet 38, the backsheet 40, the absorbent core 42, and the elastic member 44 may be assembled in various known arrangements,
A preferred diaper arrangement is generally described in U.S. Pat. No. 3,860,003 (Buell) issued Jan. 14, 1975. Alternatively, a preferred arrangement for the disposable diaper of the present invention is U.S. Pat. No. 4,808,178 issued Feb. 28, 1989 (Azitsu et al.); 1987.
U.S. Patent No. 4,695,278 issued September 22, 1989 (Lawson); and U.S. Patent No. 4,816,025 issued March 28, 1989 (Foreman).
Are also disclosed.

FIG. 3 shows a preferred embodiment of the diaper 20 in which the topsheet 38 and the backsheet 40 are coextensive and have length and width dimensions that are generally greater than the length and width dimensions of the absorbent core 42. Show. The topsheet 38 is joined to and overlaid on the backsheet 40, thereby forming the periphery of the diaper 20. The periphery defines the outer circumference or edge of the diaper 20. The perimeter includes an edge 32 and a longitudinal edge 30.

The topsheet 38 is compliant (comp
liant), is soft and does not irritate the wearer's skin. Further, the topsheet 38 is liquid permeable, allowing liquid to easily penetrate through its thickness. Suitable topsheets 38 can be made of a wide variety of materials, such as porous foam, reticulated foam, open plastic film, natural fibers (eg, wood or cotton fibers), synthetic fibers (eg, polyester or polypropylene fibers) or natural fibers. It can be manufactured from a combination with synthetic fibers. Preferably, the topsheet 38 is made of a hydrophobic material to separate the wearer's skin from the liquid in the absorbent core 42.

A particularly preferred topsheet 38 comprises staple length polypropylene fibers having a denier of about 1.5, for example, Herculestype 151 polypropylene marketed by Hercules, Inc. of Wilmington, Delaware. "Staple length fibers" means fibers having a length of at least about 15.9 mm (0.62 inches).

There are a number of manufacturing techniques that can be used to make topsheet 38. For example, top sheet 38
Can be woven, non-woven, spunbond, carded, or subjected to a similar treatment. Preferred topsheets are carded and thermally bonded by means well known to those skilled in the art. Preferably, the topsheet 38 has a weight from about 18 to about 25 g / m ^2, wet tensile strength of at least about 55 g / cm at the minimum dry tensile strength of at least about 400 g / cm and cross-machine direction in the machine direction.

The back sheet 40 is liquid-impermeable,
Other flexible liquid impermeable materials may be used, but are preferably made from a plastic film. The back sheet 40 is
Prevents exudates absorbed and contained in the absorbent core 42 from wetting articles in contact with the diaper 20, such as bed sheets and underwear. Preferably, the backsheet 40 comprises a flexible liquid impervious material, although
About 0.012mm (0.5mil) to about 0.051cm
(2.0 mils).
"Flexible" means a material that is compliant and will readily conform to the general shape and contours of the wearer's body.

A suitable polyethylene film is manufactured by Monsanto Chemical Corporation and is commercially available as Film No. 8020. The backsheet 40 preferably has an embossed and / or matte finish to provide a more cloth-like appearance. Further, the backsheet 40 may allow vapor to escape from the absorbent core 42 while still preventing exudates from passing through the backsheet 40.

The size of the backsheet 40 is determined by the size of the absorbent core 42 and the exact diaper design selected. In a preferred embodiment, the backsheet 40 extends beyond the absorbent core 42 a minimum distance of at least about 1.3 cm to about 2.5 cm (about 0.5 to about 1.0 inch) around the entire diaper periphery. To have a modified hourglass shape.

Top sheet 38 and back sheet 40
Are joined together in any suitable manner. "Joint"
The arrangement in which the topsheet 38 is directly bonded to the backsheet 40 by directly bonding the topsheet 38 to the backsheet 40, and the middle where the topsheet 38 is bonded to the backsheet 40 with the topsheet 38 It includes an arrangement in which it is indirectly joined to the back sheet 40 by being attached to a member. In a preferred embodiment, the topsheet 38 and the backsheet 40 are
Attached directly to each other around the diaper by a coupling means (not shown), such as an adhesive or other coupling means known in the art. For example, a uniform continuous layer of adhesive, a patterned layer of adhesive, or a series of discrete lines or dots of adhesive can be used to apply topsheet 38 to backsheet 40.

[0092] Tape tab fasteners 46 are typically applied to the rear waistband region of the diaper 20 to provide a fastening means for holding the diaper on the wearer.
Tape tab fastener 46 can be any of those known in the art, for example, a fastening tape disclosed in U.S. Pat. No. 3,848,594 (Buell) issued Nov. 19, 1974. These tape tab fasteners 46 or other diaper fastening means are typically applied near the corners of the diaper 20 as well.

The elastic member 44 is such that the elastic member 44 is
0, and preferably each longitudinal edge 30 adjacent the periphery of the diaper 20 to pull and hold the diaper 0 against the wearer's leg.
Are arranged along. Alternatively, the elastic member 44 can be positioned adjacent to one or both of the edges 32 of the diaper 20 to provide a waistband and / or rather a leg cuff. For example, a suitable waistband is disclosed in U.S. Pat. No. 4,515,595 issued May 7, 1985 (Kibit et al.). In addition, a method and apparatus suitable for making disposable diapers having an elastically contractible elastic member is described in U.S. Pat. No. 4,081,301 issued March 28, 1978 (Buell). Are listed.

The elastic member 44 is elastically contractible so that the elastic member 44 effectively contracts or gathers the diaper 20 in a normal unconstrained arrangement.
0. The elastic member 44 can be secured in an elastically contractible state in at least two ways.
For example, the elastic member 44 can be extended and fixed when the diaper 20 is in a non-contracted state. Alternatively, the diaper 20 contracts, for example, by pleating, and the elastic member 44
Can be fixedly connected to the diaper 20 when the elastic member 44 is in a non-relaxed or unstretched state.

In the embodiment shown in FIG. 3, the elastic member 4
4 extends a part of the length of the diaper 20. Or,
The elastic member 44 can extend the entire length of the diaper 20, or any other length suitable to provide an elastically contractible line.
The length of the elastic member 44 is determined by the design of the diaper.

The elastic member 44 can take many arrangements. For example, the width of the elastic member 44 is about 0.25 mm
(0.01 inches) to about 25 mm (1.0 inches) or more. Elastic member 44 can consist of a single strand of elastic material, or can consist of several parallel or non-parallel strands of elastic material; or elastic member 44 can be rectangular or curved. Still further, the elastic member 44 can be affixed to the diaper in any of several ways known in the art. For example, the elastic member 44 may use various bonding patterns to form the diaper 20.
Can be ultrasonically bonded, heat sealed, pressure sealed, or the elastic member 44 can be simply adhered to the diaper 20.

The absorbent core 42 of the diaper 20 is disposed between the top sheet 38 and the back sheet 40.
The absorbent core 42 has various sizes and shapes (for example,
(Rectangular, hourglass, asymmetric, etc.) and can be made from a variety of materials. However, the total absorbent capacity of the absorbent core 42 should be compatible with the design liquid load for the intended use of the absorbent article or diaper. Further, the absorbent core 4
The size and absorption capacity of the two can be varied to accommodate wearers from infants to adults. The absorbent core 42
It consists of the porous absorbent macrostructure of the present invention.

The preferred embodiment of the diaper 20 has a rectangular absorbent core 42. As shown in FIG. 4, the absorbent core 42 preferably comprises an absorbent member 48 that includes an envelope web 50 and a porous absorbent macrostructure 52 disposed on the envelope web 50. The macrostructure 52 enhances liquid capture to minimize the likelihood of precursor particles migrating through the topsheet and to provide an additional liquid transport layer between the topsheet 38 and the macrostructure 52 and Place in envelope web 50 to minimize rewet. As shown in FIG. 4, the single envelope web 50 wraps around the macrostructure 52 by folding to form a first layer 54 and a second layer 56. The edge 58 of the envelope web 50 is sealed around the perimeter by conventional means, for example, an adhesive 59 (as shown), an ultrasonic bond, or a heat and pressure bond to form a pouch. The envelope web 50 can be composed of a number of materials, including a nonwoven web, a paper web, or a web of absorbent material, such as tissue paper. The envelope web 50 preferably comprises a nonwoven web similar to the web used to form the topsheet 38. The nonwoven web is preferably hydrophilic and allows liquid to pass through the envelope web 50 quickly. A similar layered absorbent member (laminate) is 1986
This is more fully described in U.S. Pat. No. 4,578,068 issued March 25, 2018 (Cramer et al.).

Alternatively, the absorbent core 42 of the present invention can consist solely of one or more porous absorbent macrostructures of the present invention; including the macrostructures of the present invention. Combinations of layers; or other absorbent core arrangements, including one or more of the macrostructures of the present invention.

FIG. 5 shows a modified hourglass-shaped absorbent member 60 and a sheet of porous absorbent macrostructure disposed below the absorbent member 60 (ie, between the absorbent member 60 and the backsheet 40). 6 shows another embodiment of a diaper 120 comprising a two-layer absorbent core 142 comprising 62.

The absorbent member 60 quickly collects and temporarily retains excreted liquid, and wicks such liquid from the initial contact to the rest of the absorbent member 60 and the macrostructure sheet 62. Help to transport to. The absorbent member 60 preferably comprises a web or bat of fibrous material. Various fiber materials, such as those described herein, can be used in the absorbent member 60. Cellulosic fibers are generally preferred for use herein, and wood pulp fibers are particularly preferred. The absorbent member 60 can also contain a specific amount of the particulate absorbent polymer composition. Absorbable member 60
Can contain, for example, up to about 50% by weight of the polymer composition. In a more preferred embodiment, the absorbent member 60 contains from 0% to about 8% by weight of the particulate absorbent polymer composition. In another preferred embodiment, the absorbent member 60 comprises chemically stiffened cellulosic fibers as described herein. An exemplary embodiment of an absorbent member 60 useful in the present invention is described in U.S. Pat.
Nos. 673,402 (Wiseman et al.) And 198
It is described in U.S. Pat. No. 4,834,735 issued May 30, 9 (Alemeni et al.). Storage zone,
An absorbent member having a capture zone having a lower average density and a lower average basis weight / unit area than the storage zone so that the capture zone can effectively and efficiently capture waste fluids is used herein. Is particularly preferred.

The absorbent member 60 has a desired shape, for example,
It can have a rectangular, oval, oval, asymmetric or hourglass shape. The shape of the absorbent member 60 may define the general shape of the resulting diaper 120. In a preferred embodiment as shown in FIG. 5, the absorbent member 60 has an hourglass shape.

[0103] The macrostructure sheet 62 of the present invention need not be as large as the absorbent member 60 and, in fact, can have an upper surface that is substantially smaller or larger than the upper surface area of the absorbent member 60. . As shown in FIG. 5, the macro structure sheet 62 is smaller than the absorbent member 60,
It has an upper surface area of about 0.10 to about 1.0 times the upper surface area of the absorbent member 60. More preferably, the upper surface area of the macrostructure sheet 62 is only about 0.10 to about 0.75 times that of the absorbent member 60, more preferably about 0.1 times.
It will be 0 to about 0.5 times. In another aspect, the absorbent member 60 is smaller than the macrostructure sheet 62 and from about 0.25 to about 1.0 times the top surface area of the macrostructure sheet 62, more preferably from about 0.3 to about 1.0. It has an upper surface area of 0.95 times. In this alternative embodiment, the absorbent member 60 preferably comprises chemically stiffened cellulosic fibers as described above.

The macro structure sheet 62 is preferably
The diaper is placed in a specific positional relationship with respect to the backsheet 40 and / or the absorbent member 60. More specifically, the macrostructure sheet 62 is generally oriented in front of the diaper such that the macrostructure sheet 62 is more effectively positioned to capture and retain bodily fluids.

In another preferred embodiment, a plurality of macrostructures, preferably two to six macrostructure strips or sheets, can be used in place of the single macrostructure sheet 62 shown in FIG. In addition, additional absorbent layers,
The member or structure can be disposed on the absorbent core 142. For example, an additional absorbent member may be disposed between the macrostructure sheet 62 and the backsheet 40 to provide the absorbent core 142 and / or layer with storage capacity and to allow liquid to pass through the macrostructure sheet 62. Can be distributed to other parts of the absorbent core 142 or to the macrostructure sheet 62. Alternatively, the macrostructure sheet 62 can be disposed on the absorbent member 60 and disposed between the topsheet 38 and the absorbent member 60.

FIG. 6 shows a rectangular absorbent member 260 and three elongated parallel spaced apart macrostructure strips 26 disposed between the absorbent member 260 and the backsheet 40.
Diaper 220 including another two-layer absorbent core 242 including
Is shown.

The absorbent member 260 quickly collects and temporarily retains excreted liquid and wicks such liquid from the initial contacts to the rest of the absorbent member 260 and to the macrostructure strip. Useful for shipping up to 262. The absorbent member 260 preferably comprises a fibrous material, more preferably a web or batt of chemically stiffened cellulosic fibers as described herein. The macrostructure strips 262 act together to acquire and retain the excreted liquid. Macro structure strip 262
By separating the two from each other, the more effective surface area
Presented to obtain and retain the excretion liquid. This is particularly true because the spaced apart macrostructure strip 262 can swell and expand in the width direction without interfering with the ability of the adjacent strip to acquire waste liquid.

In use, the diaper 20 wears the rest of the diaper 20 such that the rear waistband region is positioned below the back of the wearer and the front waistband region is positioned across the front of the wearer. Apply to the wearer by pulling between the legs of the wearer.
The tape tab fastener 46 is then preferably secured to the outwardly facing area of the diaper 20. In use, disposable diapers or other absorbent articles incorporating the porous absorbent macrostructures of the present invention tend to distribute and store liquids more quickly and efficiently due to the high absorption capacity of the macrostructures. And tend to remain dry. Disposable diapers incorporating the macrostructure of the present invention can also be thinner and more flexible.

The absorbent macrostructures of the present invention may also be used in absorbent articles, such as those described in US patent application Ser. No. 08 / 621,030 filed Mar. 22, 1996. In particular, an absorbent article comprising a fluid-permeable topsheet, a backsheet and an absorbent core disposed between the topsheet and the backsheet. The absorbent core is
At least one upper fluid storage component capable of expanding in the z-direction to form a fluid acquisition zone upon contact with an aqueous bodily fluid;
The upper fluid storage component is in direct fluid communication with the topsheet, and the upper fluid storage component further includes the absorbent macrostructure of the present invention. The absorbent core further includes a fluid acquisition zone capable of receiving aqueous bodily fluid, the fluid acquisition zone being at least partially surrounded by the upper fluid storage component and at least partially disposed below the fluid drainage region of the absorbent core. . The absorbent core further includes a fluid acquisition / distribution component capable of acquiring and transporting an aqueous bodily fluid, at least a portion of the fluid acquisition / distribution component is disposed directly below the upper fluid storage component and is in fluid communication; And at least a portion of the fluid acquisition / distribution component is located directly below the fluid acquisition zone.

IV. Absorbent Article Performance With respect to absorbent articles comprising the absorbent macrostructures of the present invention, Applicants generally agree that fluid loading (fluid g or ml) and quota for the absorbent article. The ability to overcome the inverse relationship between the rate of fluid absorption (ml / sec) has been discovered. Thus, in one aspect, the invention provides:
An absorbent article that, in addition to being relatively thin, exhibits the ability to maintain a fluid absorption rate for each of two sequential fluid loads. In another aspect, the invention relates to an absorbent article that exhibits the ability to increase the rate of fluid absorption for each of two sequential fluid loads. Preferably, the article is each of three sequential fluid loads, more preferably four
It will show a maintained or increased fluid absorption rate for each of the two sequential fluid loads.

The ability of an absorbent article to meet this criterion is measured using an absorption test, as described in detail in the Test Methods section below. Briefly, the fluid absorption rate of a given absorbent article is measured for each of four sequential loads of 50 ml / load (each load is delivered at a constant rate of about 10 ml / synthetic urine and each load is 5 minutes equilibration time between). Articles of the present invention exhibit a maintained or increased fluid absorption rate as the number of loads increases.

For articles exhibiting a sustained fluid absorption rate for at least two sequential loads, these articles (including topsheets, backsheets and absorbent cores, but not tapes, leg cuffs, or any other (Excluding parts) is about 0.5 inches thick (about 12.7m)
m) or less, preferably about 0.25 inches (about 6.35 m
m) or less, more preferably about 0.2 inches (about 5.08 m
m) having: The thickness of the article is measured without applying pressure. Although not required, for articles of the present invention that exhibit increased fluid absorption rates for at least 2, 3 or 4 sequential loads, it is preferred that these absorbent articles also meet the thickness requirements.

In addition to exhibiting a sustained / increased absorption rate for sequential fluid loads, preferred absorbent articles include:
At least about 2 ml of fluid for the first 50 ml load
/ S, more preferably at a rate of at least about 5 ml / s. Although this is not a criterion that must be met by these articles, meeting this criterion appears to result in articles that are useful for the intended purpose.

V.Test method  A.Absorption capacity Absorbing capacity of absorbent articles is as of June 23, 1992
U.S. Pat. No. 5,124,188 (Roe et al.)
Measure according to the absorption capacity test described in columns 27 to 28.
You. In this test, the absorbent particles were
And immerse it in excess synthetic urine for a predetermined time.
And centrifuge for a specific time. Absorbable particles after centrifugation
Final weight minus initial weight (net fluid increase) vs. initial weight
The ratio of the quantities determines the absorption capacity.

B. The sarin flow conductivity (SFC) of the sarin flow conductivity (SFC) precursor absorbent particles is 199.
Co-pending U.S. Patent Application No. 219, filed March 29, 4 years,
The test is performed according to the test method described in Japanese Patent No. 574 (Goldman et al.). In this test, a gel layer is formed from absorbent particles swollen in Jaco synthetic urine under confinement pressure. This test evaluates the ability of hydrogel layers made from these absorbent particles to be present in high concentrations and to absorb and distribute bodily fluids when subjected to the applied mechanical pressure. Darcy's law and the steady state flow method are used to measure sarin flow conductivity (see, eg, "Absorptive", edited by PK Chatelje, Els Beer, 1985,
Pages 42 to 43 and "Chemical Engineering", Vol. II, No. 3
Edition, J. M. Coleson and J.M. F. Richardson, Pergamon Press, 1978, pp. 125-127). The test fluid for the SFC test is Jaco synthetic urine.

C. Absorbency Under Pressure (PUP) The under-pressure performance (PUP) of the pre-absorbent particles is 199.
Co-pending U.S. Patent Application No. 219, filed March 29, 4 years,
The test is performed according to the test method described in Japanese Patent No. 574 (Goldman et al.). This test is performed at 0.7 psi (about 0.5 kPa).
Measure the g / g absorption of synthetic urine for 60 minutes in the case of absorbent particles which are laterally confined in the piston / cylinder assembly under the confinement pressure of ()). This test evaluates the ability of a layer of absorbent particles to be present at high basis weights and concentrations and to absorb bodily fluids during actual time when subjected to use pressure. These operating pressures may include mechanical pressure resulting from the weight and / or motion of the wearer, mechanical pressure resulting from the elastics and fastening systems, and adjacent capillary (eg, fibrous) layers and / or structures when draining fluid. And static pressure suction resulting from The test fluid for the PUP performance test is Jaco synthetic urine. This fluid is absorbed by the absorbent particles under demand absorption conditions at a static pressure close to zero.

D. Demand Absorbing Capacity The demand absorbing capacity of the absorbent macrostructure was a pressure of 1.4 psi (about 10 kPa) at the beginning of the test (dry) and 0.7 psi (about 5 kPa) at the end of the test (wet swelling). It is designed to measure the g / g absorption of synthetic urine for 60 minutes for absorbent structures under pressure. This test evaluates the absorbent structure's ability to absorb bodily fluids over an actual period of time when the absorbent particles are present at high basis weight and high concentration and are subjected to use pressure. These operating pressures may include mechanical pressure resulting from the weight and / or motion of the wearer, mechanical pressure resulting from the elastics and fastening systems, and adjacent capillary (eg, fibrous) layers and / or structures when draining fluid. And static pressure suction resulting from The test fluid for the demand absorption capacity test is Jaco synthetic urine. This fluid is absorbed by the absorbent structure under demand absorption conditions.

The following describes a demand absorption capacity measurement. The sample cell is a square piston / cylinder assembly and has a mesh bottom of dimensions 10 cm x 10 cm. The absorbent structure (with or without fibers) measures 3.7 cm x 3.
A 7 cm sample is placed in a 1.4 psi piston. When the sample is brought into contact with the Jaco synthetic urine, it begins to absorb the Jaco synthetic urine. The change in weight is continuously monitored and recorded for the next 60 minutes. As a result, the dimensions of the sample were constant at 1.4.
When placed under an external pressure of psi, it is increased by about 100%.

E. Absorption test This test simulates the introduction of urine into a diaper under the following conditions. 1) Apply a pressure of 0.4 psi (about 28 g / cm ² ) to the diaper sample. 2) Apply a total of two or more charges of synthetic urine at a rate of 10 ml / sec to the diaper sample (there is a 5 minute time between each charge (equilibration time)).

The following equipment is used. Conditioning Chamber: Control temperature and humidity within the following limits: Temperature: 73 ± 2 ° F. Relative humidity: 50 ± 2% Absorption tester: Concord-Len Company, 6315 Warwick Street, Cincinnati, Ohio (45227) Part Test Floor (Plexiglass) Foam Base-6 "x 20" x 1 "(about 15.2cm x about 50.8cm x 2.5cm) Foam-Foam Mold Covered with Polyethylene Backsheet Material: Density 1. 0 lb / cu.ft. IDL 24 psi Nozzle Cover Plate Measuring Cylinder: VWR Scientific, (100 ml) Catalog Number: (100 ml) (1,000 ml) 24711-310 (1,000 ml) Catalog Number: 247711-364 or equivalent Erlenmeyer flask: VWR Scientific Catalog Number: 2913 -30 (6,000 ml) 7 or equivalent Digital Pump: Cole-Palmer Instrument Company; Tel. No. (800) 323-4340, USA, Catalog Number: G-075323-20 Pump Head: Cole-Palmer・ Instrument Company Catalog No .: G-07518-02 Distilled water: Convenient water source Dry synthetic urine: Jaco synthetic urine

V. Of the production of the macrostructure according to the invention
Specific Illustrative The following examples further describe and demonstrate preferred embodiments within the scope of the present invention. These examples are given for illustrative purposes only and should not be construed as limitations on the invention, as many changes may be made without departing from the spirit and scope of the invention.

Example 1 This example illustrates how to make the absorbent macrostructure of the present invention. Absorbent macrostructures are made on a shuttle table by first papering the superabsorbent polymer granules on a cellulose web and then spraying an aqueous solution containing Kaimin. The shuttle table is designed to move back and forth for continuous production of superabsorbent polymer granules and
It has a speed range from m / min to 30 m / min. The shuttle table is equipped with a fixed automatic powder feeder system for superabsorbent polymer granules having a flow rate in the range of 100-1000 g / min, and a fixed automatic solution spray system with a spray rate of 40-200 g / min. Typical operating conditions are 1
Includes 0 m / min shuttle speed, 212 g / min superabsorbent polymer particulate feed rate, and 76 g / min solution spray rate.

Two different superabsorbent polymer granules are used in this example. Both are crosslinked sodium polyacrylates. The first superabsorbent polymer is supplied by Nippon Shokubai under the trade name AQUALIC CA-L76 and has a high PUP and a medium gel volume. The second crosslinked sodium polyacrylate is IM-1000 supplied by Sanyo Chemical Industries and has a low P
Has UP and high gel volume. Cellulose web is a tissue towel available under the trade name Bounty having a basis weight of 20 g / m 2. Kaimin has been licensed by the Hercules Company to Kaimin PLU.
It is supplied under the trade name S and contains 30% of a polymer resin. The blending of at least two superabsorbent polymer granules is performed in a food mixer. The spray solution contains 10% by weight kaimin polymer resin, 45% glycerol, and 45% water. An additional 10% of a latex polymer based on polyethyl acrylate, supplied under the trade name Mowinil 963 by Hoechst Synthetic, is incorporated into the solution. The presence of a latex polymer based on polyethyl acrylate is added to increase the flexibility and flexibility of the macrostructure.

The macrostructure obtained contains 77% of superabsorbent polymer, 19% of solution and 4% of cellulosic tissue towel. The total basis weight of the macrostructure is 480 g / m 2 including 370 g superabsorbent polymer, 90 g spray solution and 20 g bounty towel.
The weight ratio of the two superabsorbent polymers is 0% to 100%.

Example 2 This example illustrates how to make the absorbent macrostructure of the present invention. Except that the structure is made by bonding the aquaric CA-L76 superabsorbent polymer to one side of the tissue web and bonding the IM-1000 superabsorbent polymer to the other side of the web, the absorbent macrostructure is Prepared by following the method described in Example 1.

The macrostructure obtained contains 77% of superabsorbent polymer, 19% of solution and 4% of cellulosic tissue towel. The total basis weight of the macrostructure is 480 g / m 2 including 370 g superabsorbent polymer, 90 g spray solution and 20 g bounty towel.
The weight ratio of the two superabsorbent polymers is 0% to 100%.

Example 3 This example illustrates the preparation of an infant diaper containing the absorbent macrostructure of the present invention. Applying the absorbent macrostructure of Example 1 to a diaper core size, applying a fluid impermeable backsheet film, a wood fiber acquisition layer and a non-containment topsheet;
Thereby forming an infant diaper.

The obtained diaper was made of about 40 superabsorbent polymers.
% Due to the high concentration of superabsorbent polymer compared to a typical infant diaper core containing 70% by weight.

Example 4 This example illustrates how to make a diaper containing the superabsorbent macrostructure of the present invention. A superabsorbent macrostructure is prepared according to the method of Example 1, except that the concentration of the superabsorbent polymer is increased to 90% by increasing the basis weight of the superabsorbent polymer to 1550 g / m2 or more. The macrostructure is then slit and stretched to form a mesh core. The core is then coated with a fluid impermeable backsheet film, a wood fiber acquisition layer and a nonwoven topsheet to make an infant diaper. Diapers exhibit a very low thickness due to the high concentration of superabsorbent polymer in the core as compared to normal baby diapers.

Example 5 This example demonstrates the surprising use of cationic amino-epichlorohydrin adducts such as Kaimin in the absorbent macrostructures of the present invention, which enhances the demand absorbing capacity of the macrostructures. Indicates that

FIG. 7 illustrates a comparison of the demand absorbing capacity of the absorbent macrostructure of the present invention compared to three different samples. In particular, the curve "-o-" illustrates the surprising effect of Kaimin on boosting demand under pressure over the entire range of mixing ratios of two different superabsorbent polymers. This is a similar structure (curve "-◇-") produced without the use of Kaimin.
[0.7 psi demand absorption capacity increases only stepwise at increasing weight percent of high PUP superabsorbent particulate (L-76)]. Curve "-◇-" is also identical to curve "-△-" which is the result of testing a layer of mixed superabsorbent granules without Kaimin or glue adhesive. Another example of forming an absorbent structure that does not use kaimin is to first sandwich a layer of superabsorbent polymer particulate between two plies of tissue and adhere the tissue to form a laminate composite. is there. This laminated structure (curve “-□
-") Does not show an extraordinary relationship (as seen by the curve" -o- ") between the demand absorption capacity under pressure and the mixing ratio of the superabsorbent polymer.

All publications, patent applications, and issued patents mentioned above are hereby incorporated by reference in their entirety.

The examples and embodiments described herein are for illustrative purposes only, and various modifications or alterations thereto will be suggested to those skilled in the art and the spirit and scope of this application and the claims It is understood that they should be included in the scope.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph of a typical macrostructure of the present invention. The macrostructure shown is made using irregularly shaped superabsorbent polymers and spherical superabsorbent polymers.

FIG. 2 is a scanning electron micrograph of the macrostructure of the present invention. The structure is made by bonding one irregularly shaped superabsorbent polymer on one side of a fibrous web and bonding a spherical polymer on the other side.

FIG. 3 is a topsheet portion showing a lower absorbent core of a diaper (an embodiment of the absorbent member according to the present invention) (in which the absorbent member includes the porous absorbent macrostructure according to the present invention). 1 is a cutaway perspective view of a disposable diaper embodiment according to the present invention.

4 is a cross-sectional view of the absorbent core of the diaper shown in FIG. 3 taken along section line 6-6 of FIG.

FIG. 5 is a perspective view of a disposable diaper embodiment according to the present invention wherein a portion of the topsheet has been cut away to reveal another bilayer absorbent core embodiment.

FIG. 6 is an open view of parts of the diaper structure (one of the parts is another two-layer absorbent core and the absorbent macrostructure is in the form of a plurality of strips).

FIG. 7 is a profile of the demand absorption capacity of various macrostructures vs. weight% of high PUPL-76 superabsorbent polymer in different macrostructures.

[Explanation of symbols]

 Reference Signs List 20 diaper 38 top sheet 40 back sheet 42 absorbent core 52 porous absorbent macro structure 60 absorbent member 62 macro structure sheet 120 diaper 142 two-layer absorbent core 242 two-layer absorbent core 260 absorbent member 262 macro structure Object strip

──────────────────────────────────────────────────続 き Continuation of the front page (73) Patent owner 592043805 ONE PROCTER & GANB LE PLAZA, CINCIN NAT I, OHIO, UNITED STATS OF AMERICA (58) Fields investigated (Int. Cl. ⁶ , DB name) C08J 9 / 00-9/42

Claims (10)

(57) [Claims] A porous absorbent macrostructure having improved fluid handling capabilities comprising an interparticle aggregate comprising a number of interconnected crosslinked particles comprising a substantially water-insoluble absorbent hydrogel-forming polymeric material. Wherein said hydrogel-forming polymeric material comprises: (a) a sarin flow conductivity (SFC) value of at least 5 × 10
^-7 cm ³ sec / g and confinement pressure 0.7 psi (5 kP
a) Under-pressure performance (PUP) capability value of at least 23
50-95% of the first hydrogel-forming polymer having g / g
And 5 to 50% of a second hydrogel-forming polymer having an absorption capacity value of at least 25 g / g, (b) a first hydrogel-forming polymer 20 in the form of spherical particles
And (c) a mixture selected from the group consisting of (a) and (b) in the form of a mixture of (a) and (b). The interbonded agglomerates have pores between adjacent particles that are interconnected by interconnecting channels to form a liquid-permeable macrostructure having a circumscribed dry volume of 0.008 mm ³ A porous absorbent macro structure characterized by the above. 2. The hydrogel-forming polymer material comprising 20-40% of a first hydrogel-forming polymer in the form of spherical particles and 60-80% of a second hydrogel-forming polymer in the form of non-spherical particles.
The porous absorbent macrostructure according to claim 1, consisting of a mixture with: 3. The method of claim 2, wherein said hydrogel-forming polymeric material has a sarin flow conductivity (SFC) value of at least 5 × 10 ⁻⁷ cm ³ s /
g and the first hydrogel-forming polymer having a performance under pressure (PUP) capacity of at least 23 g / g under 0.7 psi (5 kPa) confinement pressure; The porous absorbent macrostructure according to claim 1, comprising a mixture with 5 to 50% of a dihydrogel-forming polymer. 4. The absorbent macrostructure according to claim 1, wherein said particles are cross-linked at their surface with a cationic amino-epichlorohydrin adduct. 5. The absorbent macrostructure according to claim 1, further comprising a plasticizer. 6. The absorbent macrostructure according to claim 1, further comprising a latex material. 7. An absorbent article comprising a liquid-permeable topsheet, a liquid-impermeable backsheet joined to the topsheet, and an absorbent core disposed between the topsheet and the backsheet. An absorbent article wherein the absorbent core comprises one or more macrostructures according to claim 1. 8. The absorbent core further comprises an absorbent member disposed between the topsheet and the macrostructure, wherein the absorbent core comprises chemically stiffened cellulosic fibers.
The absorbent article according to claim 7. 9. The absorbent article according to claim 7, wherein said article is a diaper. 10. A flexible porous absorbent sheet comprising an interparticle aggregate comprising a number of interconnected crosslinked particles comprising a substantially water-insoluble absorbent hydrogel-forming polymeric material, said flexible porous absorbent sheet comprising: The polymer material has: (a) a sarin flow conductivity (SFC) value of at least 5 × 10
^-7 cm ³ sec / g and confinement pressure 0.7 psi (5 kP
a) Under-pressure performance (PUP) capability value of at least 23
50-95% of the first hydrogel-forming polymer having g / g
And 5 to 50% of a second hydrogel-forming polymer having an absorption capacity value of at least 25 g / g, (b) a first hydrogel-forming polymer 20 in the form of spherical particles
And (c) a mixture of (a) and (b), wherein the mixture is selected from the group consisting of: The interparticle bonded aggregate has pores between adjacent particles, which are interconnected by interconnecting channels to form a liquid permeable macrostructure, the circumscribed dry volume of which macrostructure is 0.008 mm ^{3. A} flexible porous absorbent sheet, wherein the number is ³ or more.