CA2242642A1

CA2242642A1 - Absorption of water

Info

Publication number: CA2242642A1
Application number: CA 2242642
Authority: CA
Inventors: Ervin Dan; Amy Zhong
Original assignee: Individual
Current assignee: Camelot Superabsorbents Ltd
Priority date: 1995-10-24
Filing date: 1996-10-21
Publication date: 1997-05-01
Also published as: WO1997015367A1; AU7296396A; EP0862488A1

Abstract

The use of a water-absorbent composition is described which absorbs water in the presence of multiple valent ions. The water-absorbent composition is a polymeric material having two or more pendant carboxylic acid groups which are located in close proximity.

Description

CA 02242642 l998-07-03 WO 97/15367 PCT/EPS''~1557 Absorption of Water The present invention relates to the absorption of water cont~ining ions having a multipie valency. More particularly, the present invention relates to the use of a water-absorbent polymeric composition of the kind known as superabsorbent material to absorb water cont~ining multiple valent ions, particularly divalent ions.

As used herein the term "water" when used alone or in phrases such as "water-absorbing", "water-absorbent" and "water-swellable" is understood to mean not only water but also aqueous media such as, in particular, electrolyte solutions such as body fluids.
A large number of compositions have been developed which exhibit the capacity to be water-absorbing. Known compositions may be in any suitable form including powders, particles and fibers Examples of two such water-absorbent compositions are described in US3,954,721 and 3,983,095, incorporated herein by reference, which disclose preparations for derivatives of copolymers of maleic anhydride with at least one vinyl monomer in fibrous form. The fibrous copolymers are rendered hydrophillic and water-swellable by reaction with ammonia or an alkali metal hydroxide. US Patent No. 3 810 468, which is incorporated herein by reference, discloses lightly cross-linked olefin-maleic anhydride copolymers plG~dl~d as substantially linear copolymers and then reacted with a diol or a diamine to introduce cross-linking. The result~nt lightly cross-linked copolymers are treated with ~mm~ni~ or an aqueous or alcohol solution of an alkali metal hydroxide. US Patent No. 3 980 663, which is incorporated herein by reference, describes water-swellable abso~
articles made from carboxylic polyelectrolytes via cross-linking with glycerine diglcidyl ether.

Eulu~eal~ Published Application No. 0 268 498 (incorporated herein by reference) describes a water-absorbent composition formed by causing a substantially linear polymer of water-soluble ethylenically ullsaluldted monomer blends comprising carboxylic and hydroxylic monomers to cross-link int~n~lly.

Further examples of water-absolb~ compositions are those produced from copolymers of an a, B unsaturated monomer having at least one pendant unit selected from a carboxylic acid Sl,~. 111 I.JTE SHEET (RULE 26) WO 97/1~;367 PCT/EP~61~1r57 group and deliv~liv~s thereof and a copolyll.elisable monomer.

A ~,lopollion of the pendant units are present in the final copolymer as the free acid and a proportion as the salt of the acid. These copolymers are capable of being cross-linked, either int~ lly or with a variety of cross-linking agents, to form the water-swellable composition.
l~xamples of water--swellable compositions of this type can be found in US 4,616,063, 4,705,773, 4,731,067, 4,743,244,4,788,237, 4,813,945, 4,880,868 and 4,892,533 and EP 0 272 074, 0 264 208 and 0 436 514. These patents and applications are incorporated herein by reference.

Derivatives of carboxylic acid groups include carboxylic acid salt groups, carboxylic acid amide groups, carboxylic acid imide groups, carboxylic acid anhydride groups, carboxylic acid ester groups and the like.

Other examples of water-absorbent compositions can be found in US 4,798,861, W0 93/17066, W0 93~255735, W0 93/24684, W0 93/12275, EP 0 401 044, 0 269 393, 0 326 382, 0 227 305, 0 101 253, 0 213 799, 0 232 121, 0 342 919, 0 233 014, 0 268 498 and 0 397 410, GB 2082614, 2022505, 2270030, 2269602 and 21 '6591, US 4~18163, 3989586, 4332917, 4338417, 4420588 and 4155957 and FR 25251 ' 1 which are all incorporated herein by reference.

Many of the known water-absorbent compositions having pendant carboxylic acid groups have reduced ability to absorb water which coll~aills multi~ alent ions, such as divalent ions.
Without wishing to be bound by any theory, it is believed that the ions present in the water react with the carboxylic acid groups. As the product of this reaction is insoluble, the absorption of the ions results in the precipitation of the ~ ater-absorbent composition which is then no longer capable of absorbing water.

This is a particular problem where the water to be absorbed contains a large proportion of multivalent ions. One example of such water is sea water. which contains a number of salts inrluAin~; divalent ionic salts such as MgC12, CaC12 and SrCl2. As a typical use of water-absolL.~n~ compositions is as a wrap to protect under sea cables from the effects of sea water, 1 UTE SHEET (RULE 26) WO 97/15367 PCT/EF~61!~ 1557 the ability to absorb sea water is particularly important. Multivalent ions can also be found in other "waters" which are generally absorbed by these water-absorbent materials. Examples of the waters include, general spillages, bodily fluids and the like.

We have now discovered that the aforementioned problems can be alleviated or overcame by the use of a water-absorbent composition having pendant carboxylic acid groups arranged in mutual proximity to absorb water co-,ti-;"i"g multivalent, particularly divalent ions. It will be understood that the term "cont~ining" in-~lud~s the water absorption occurring in the presence of the multivalent ions.

Thus, according to the present invention there is now pro- ided the use of a water--absorbent composition to absorb water cont~ining multivalent ions wherein the water-absorbent composition has pendant carboxylic acid groups and wherein two or more such groups react with the ions and the composition does not precipitate.

The two or more such pendant carboxylic acid groups are preferably located in close p~ iLy. Where the ion to be absorbed is divalent, the pendant carboxylic acid groups are preferably located on the polymeric backbone in close proximity, most preferably, the carboxylic acid groups are located on adJacent carbons on the backbone of the polymer.

Without wishing to be bound by any theory, it is belie~ ed that each of the carboxylic acid groups in the two or more ~end~llL groups react with, and complex, the multivalent ion. Th r~slllt~3nt composition does not ~ te thereby ~verco.ning the aforementioned problem.

DETAILED DESCRIPTION OF PREFERRED
EMBODIMENTS OF THE INVENTION

Particularly suitable copolymers for use in the production of the water--absorbing compositions used in the present invention will contain from about ~S to about 75 mole ~ percent recurring units of at least one ~ -ulls~lu-dl~d monomer and from about 75 to about 25 mole percent recurring units of at least one copolymerizable monomer. The copolymer preferably contains from about 35 to about 65 mole percent of recurring units of at least one SUe~S 1 1 1 UTE SHEET (RULE 26) WO 97/15367 PCT/EP~)6/04,57 K,~-unsaturated monomer and from about 65 to about 35 mole percent of at least one copolymerizable co-monomer. Most preferably, the copolymer will be an equimolar copolymer.

Suitable c~ n~t--r~tcd monomers are those bearing at least one pendant carboxylic acid unit or derivative of a carboxylic acid unit. Derivatives of carboxylic acid units include carboxylic acid salt groups, carboxylic acid amide groups, carboxylic acid imide groups, carboxylic acid anhydride groups and carboxylic acid ester groups.

Examples of suitable a~ n!c;~t~ ted monomers include m~leic acid, crotonic acid, fumaric acid, mesaconic acid, the sodium salt of maleic acid, the sodium salt of 2-methyl, 2-butene dicarboxylic acid, the sodium salt of itatonic acid, maleamic acid, maleamide, N-phenyl maleimide, maleimide, maleic anhydride, fumaric anhydride; itaconic anhydride, citraconic anhydride; mesaconic anhydride, methyl itaconic anhydride, ethyl maleic anhydride, diethylmaleate, methylmaleate; and the like, and their mixtures. Monomers having two carboxylic acid groups ~tt~rh~orl to ad~acent carbon atoms are particularly preferred.

Any suitable copolymerizable co-monomer can be employed. Examples of suitable copolymerizable co-monomers include ethylene, propylene, isobutylene, C, to C4 alkyl methacrylates, vinyl acetate, methyl vinyl ether, isobutyl vinyl ether, and styrenic compounds having the formula:

wherein R lCpl~,Se~ i hydrogen or an aL~cyl group having from 1 to 6 carbon atoms, and wherein the benzene ring may be sub:~ilul~d with low molecular weight alkyl or hydroxyl groups.

Suitable Cl to C4 alkyl acrylates include, for example, methyl acrylate, ethyl acrylate, isoplupyl acrylate, n-propyl acrylate, n-butyl acrylate, and the like, and their mixtures.

SUlv~ 1 1 1 UTE SHEET (RULE 26) Suitable C, to C4 alkyl methacrylates include, for example, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-propylmethacrylate, n--butyl methacrylate, and the like, and their mixtures.

Suitable styrenic compounds include, for example, styrene, a-methylstyrene, p-methylstyrene, t-b~lLy~y~ e, and the like, and their mixtures.

The pendant units on the a,~3-unsaturated monomer, will determine what, if any, additional reactions must be carried out to obtain a copolymer having the requisite pendant units necessary to produce the water-absorbing compositions of this invention. Preferably these water-absorbing compositions will contain from about '0 to about 80 percent pendant carboxylic acid units and from about 80 to about 20 percent pendant carboxylate salt units.
Prefe}ably, both units are present in an amount of from about 30 to about 70 percent.

In general, if the cc,B--Inc~t-lr~tçcl monomer bears only carboxylic acid amide, carboxylic acid imide, carboxylic acid anhydride, carboxylic acid ester groups or mixtures thereof, it will be n~.cçc.c~ry to convert at least a portion of such carboxylic acid derivative groups to carboxylic acid groups by, for example, a hydrolysis reaction. If the c~,B-unsaturated monomer bears only carboxylic acid salt groups, acidification to form carboxylic acid groups will be neceSs;~,~/ using methods and materials well known in the art Similarly, the final copolymer should contain from about 80 to 20 percent pendant carboxylate salt units. Accordingly, it may be necessary to carry out a neutralization reaction.
Neutralization of carboxylic acid groups with a strong organic or inorganic base such as NaOH, KOH, ammonia, ammonia-in-water solution, or organic amines will result in the formation of carboxylate salt units, preferably carboxylate metal salt units.

The sequence and the number of reactions (hydrolysis, acidification, neutralization, etc) carried out to obtain the desired functionality attached to the copolymer backbone are not critical.

One copolymer particularly suitable for use in the present invention is a copolymer of maleic SU~S ~ JTE SHEET (RULE 26) CA 02242642 l998-07-03 WO 97tl5367 PCT/EP~ 1557 anhydride and isobutylene. Another is maleic anhydride and styrene. Suitable copolymers will have peak average molecular weights of from about 6,000 to about 500,000 or more.

~iuitable copolymers of maleic anhydride and isobutylene can be ~cpdl~d using any suitable COIlv~ llLional method. Such copolymers are also commercially available from Kurary Isoprene Chemical Company, Ltd., Tokyo, Japan under the tr~ nnz~rk ISOBAM. ISOBAM copolymers are available in several grades which are lliL[tl~ ted by average viscosity molecular weight:
ISOBAM--10, 160,000 to 170,000; ISOBAM-06, 80,000 to 90,000; ISOBAM-04, 55,000 to 65,000 and ISOBAM-600, 6,000 to 10,000.

The copolymer is then preferably cross-linked either intemally via covalent or hydrogen bonding or using an external cross-linking agent. Suitable cross-linking agents include:
monomers co.-t~;"i"g at least two hydroxyl groups such as alkylene glycols cont~ining Z-10 carbon atoms and their ethers, cycloalkylene glycols, Bisphenol A, hydroxy alkylene derivatives of Bisphenol A, hydroquinone, phloroglucinol, hydroxy alkylene derivatives of diphenols, glycerols, Glylhlilol, pentaclylhlilol, and mono--, di- or oligt~s~r~h~rides;
heterQcyclic carbonates; and monomers CO~ ;llil.p at least one amine group and at least one hydroxyl group such as ethanolamine, tris (hydroxymethyl) aminomethane, 3-amino-1-propanol, DL--1-amino--2-propanol, 2-amino-1-butanol, N,N-dimethylethanolamine, diiso~lopa,lol-amine methyl diethanol amine, triethanol amine, 2-(methylamino)ethanol and the lil~e.

In general cross--linking will not occur and the product will not become absorbent until the partially neutralized polymer reaction product is heated to a telllpl laLLIlG sufficient to effect reaction between the cross-linking agent and the copolymer.

The cure conditions required to achieve optimal cross-linking depends upon several factors, including the particular polymer employed. For example, the cure tt~ .atulG will depend on the polymer. If the polymer is a partially neutralized ethylene/maleic anhydride copolymer, a cure teul~ldlule of at least 140~C will be required to achieve cross-linking.
If the polymer is partially neutralized styrene/maleic anhydride copolymcr, a telll~ dlulG of at least about 150~C is required to cross-link; and if a partially neutralized isobutylene/maleic Sll~ 111 ~ITE SHEET (RULE 26) CA 02242642 l998-07-03 anhydride copolymer is employed, a tell.pc.dLure of at least about 170~C will be required to achieve cross-linking Cure times can vary dep~ntling on cure te.~,eldtures and on the amount of reactive compound used. Cure times will typically be within the range of from about 0.5 to about 20 minlltes, preferably 0.5 to 15 minutes, and most preferably 0.5 to 12 minutes. To m~imi~e absoll,tlll pl~yellies, optimal cure of the composition (ie. minim~l amount of cross-linking needed to form a cross-linked network) is required. Optimal cure is achieved by adjusting a number of variables within wide ranges depending upon the specific syrup composition. Optimal cure conditions require, among other things, a balance between cure time and cure te~ eldlulc.

As is readily a~pdlcllt from the high te~ eldtulc required to achieve cross-linking, the aqueous reaction product of the partially neutralized polymer and the reactive compound, ie.
the grafted polymer syrup, can be stored for an unlimited time. This unlimited room lclllp~ldture stability facilitates further processing of the syrup into any number of conventional forms, in~ lu-ling fibers and films using conventional methods. For example, the syrup can be further processed by casting, spray drying, air-assisted spray drying, air ~ttrml~tion, wet spinning, dry spinning, flash spinning, and the like. To facilitate the removal of water from the aqueous composition during the spinning process, minor amounts of other polar solvents such as alcohol can be added to the aqueous syrups. The rçsnlt~nt fibers can be further processed into milled fibers, chopped fibers, fluff or bulk fibers, strands, yarns, webs, composites, woven fabrics, non-woven fabrics, non-woven mats, tapes, scrim, and the like, using a variety of methods including twisting, beaming, sl~hing, warping, quilling, severing, crimping, lrxL~ g~ weaving, knitting, braiding, etc., and the like.

The water-absorbent compositions may be formed into a composite web colllL lisi~g non-water absorbent fibers and water-absorbent fibers. The fibers of these webs may be bonded using any suitable technique. Suitable non-water-absorbent fibers include rayon fiber, cellulose ester fiber, protein fiber, polyamide fiber, polyester fiber, polyvinyl fiber, polyolefin fiber, polyurethane fiber, aramid fiber, glass fibers and mixtures thereof.

The composite webs may be used in articles of m~nllf~cture such as disposable diapers, sdllildly napkins, tampons, pant liners, adult incontinence pads, coverstock for r~ h~e SUBSTITUTE SHEET (RULE 26) CA 02242642 l998-07-03 WO 97/15367 PCT/EP~)6/01557 hygiene products, surgical and dental sponges, bandages, patient underpads (for example pairs of the type described in US5814101, US4342314 and EP0052403 when are incorporated herein by reference), wipes, domestic wipes, industrial wipes, pacl~ging, filters, medical tray pads, fenestration drapes, opelalillg gowns; mortuary pads, other medical related devices, casket liners, forensic rx,~ tion pads, cable wrap, food tray pads, food preservation articles, seed germination pads, capillary mats, baby bibs, desiccant strips for anti-rust use, bath mats, sorbents, breast pads, underarm pads, wound covers, pet litter, roofing materials, automotive trim, furniture, bedding, clothing, soil modifiers, spill control materials; waste m~n~gement materials and protective articles.

These articles of m~nllf~/ hlre are found to be particularly effective in absorbing water co"l~i"i"g multivalent ions, particularly divalent ions.

Water cont~ining divalent ions include sea water, menses and urine The composition of synthetic sea water - which is believed to correspond to a typical sea water - is set out in Table 1.
Table 1 Salt g/l NaCl 24.54 MgC12 ~ 6H2~ 11.10 Na2S04 4.09 CaCl2 1.16 KCl 0.69 NaHCO3 0.20 KBr 0.10 H3B03 0.03 SrC12 ~ 6H2~
NaF 0.003 It can therefore be seen that sea water Collt~il.s a substantial amount of divalent ions.
Therefore using the compositions of the present invention as cable wrap for undersea S~JI_~ 111 ~JTE SHEET (RULE 26) applications is particularly suitable to protect the cable from the effect of the sea water.

The composition of synthetic adult urine - which is believed to correspond to typical adult urine - is set out in Table 2.

Table 2 Ingredients g/L

Urea 20.5 NaCI 8.5 (NH3)2 2.5 K2S04 4.0 Citric acid H2 MgC12- 6H20 1.1 CaCI2 ~ 6H20 0.8 L. Histidine HCl 0.7 Albumine bovine 0.1 Preserving agent 1.0 Deionised water 960.3 pH Adjuster 6.0 It can therefore be seen that adult urine contains a substantial amount of divalent ions.
Therefore, the compositions of the present invention are particularly useful in, for example, adult incontinence pads.

The following examples are illustrative of the present invention but should not be construed as limitin~; the invention in any way.

Prepared samples of water-absorbent compositions were tested for water absorbency and fluid retention using the "tea bag" test.

SUBSTITUTE SHEET (RULE 26) WO 97/15367 PCT/EP~)6/04557 The "tea bag" test was carried out as follows. First 10 pieces of tea bag paper are cut to 5"
x 2" and folded to 2.5" x 2" and heat sealed on 2 sides. These bags are then soaked in a test solution, removed, dabbed lightly with filter paper to remove excess saline solution and weighed. These weights are then averaged and the value is recorded as "W2". In to a triplicate set of tea bags measuring 5" x 2" is placed a~pio~c;lll~tely 0.2 grams of water-absorbent solvent, the exact weight of which is recorded as "W3", the bags loaded with the sample are heat sealed. The triplicate sample CO~ .i"i"g tea bags are then placed in a test solution, with stirring~ for 10 minllt~ c. Each tea bag is then removed from the test solution, allowed to drain for 10 seconds and then dabbed lightly with filter paper to remove excess test solution. Each sample co,.l;.;~i"g tea bag is then weighed and recorded as "Wl". Each sample cont~ining tea bag is then placed in a Buchner porcelain funnel, a small amount of test solution is poured over the same to re-saturate it, and then the sample cont~ining tea bag Is exposed to a vacuum of 0.5 psi for 5 minl-tes The sample is removed and weighed and the weight is recorded as "W4".

The Free Swell Liquid Retention (FS) is det~nnin~d using the formula:

g/g=[Wl-W~/W3]--1 The 0.5 psi Liquid Retention (Rl~ is ~ tçnnin~fl using the fo~nula:

g/g=[W4--W2)/W3] -- 1 where W, = final free swell weight in grams of gel plus wet tea bag, W2 = average weight in grams of 10 empty, wet tea bags, W3 = original weight in grams dry staple fiber, and W4 = final 0.5 psi weight in grams of gel plus wet tea bag.

Examples Commercially available water-abso~ nt powders A and B were tested in accordance with the above-mentioned test protocols. A water--absorbent composition of the preferred embodiments of the invention were pl~pal~d and tested according to the above-mentioned SUBSTITUTE SHEET (RULE 26) WO 97/1~367 PCT/EP~r 't., l~57 test protocols. Th~ results Or the tests are set out ln Table 3.
Table 3 Test Solution Comoosition of Powder A Powder B
the mYention F.S. R.T. F.S. ' R.T. F.S. R.T.
n-i~ni~d wa~er 351.7 249.8 278.1 190 6 209.2 148.1 0.170 CaCI. 117 92.4 58.5 50 1 73.6 59.3 0.3% CaClz 62.1 38.6 19.3 1 10 26.1 16.1 0.5% C~Cl2 ~6.5 36.1 g.6 1 7 1 5.5 3.5 l~a CaCIz ~3.2 27.9 3.49 2 17 lQ.~ 5.8 0.5~ C2~O~)~ 70.3 52.9 18.3 1~ 5 33 4 26.7 l~ C~O~)~ 47 34.1 6.2 ' 5.5 7 6 0.5% FeS0, 81 56.9 33 25 ~ 22.4 15.8 1% FeS0~ 64.2 35 7 13.5 7 7 8 6 3.2 0.1 % F~(SO~)~ I 12.7 80.2 95 74.3 1oa.2 75.5 0.5% F~(SO4), 43.4 24.7 4~.1 ;0 8 38.9 29.6 O.l~o MgSO, 122.5 87.7 85.5 61.4 69 5 50.8 0.5~o MgSO~ 66 43.4 20 12 2 23.2 15.8 l~ MgSO~ 55 42.7 11.9 9.3 7.5 6 s~wu~r 51.4 38.4 11.3 10.2 11.~ 8.7 (synth~tEc) S~a Water 57.5 43.8 lg.5 16.2 14.9 l 2 2 ~v~
l~ Urca 372.8 239 268.1 171 3 2~2.5 151.3 s~ ur a 351.9 233.2 260.4 171.7 238.6 148.4 10% Ur:a 247 177.2 230.9 172.1 215.8 151.7 0.5% ZnSO4 78.5 54.2 42.1 30.3 45.5 3l~6 1~ ZnSO4 67.7 50.9 20.8 15.1 20 5 13.5 2% ZnSO~ 53.5 39.8 14.2 10.3 10 2 6 SUBSTITUTE SHEET (RULE 26)

Claims

1. The use of a water-absorbent composition to absorb water containing multivalent ions characterised in that the water-absorbent composition is a polymeric material having two or more pendant carboxylic acid groups located in close proximity.

2. The use according to Claim 1 of a water-absorbent composition to absorb watercontaining divalent ions characterised in that the water-absorbent composition is a polymeric material having two pendant carboxylic acid groups located in close proximity.

3. The use according to Claim 1 or Claim 2 wherein the pendant carboxylic acid groups are located on the polymeric backbone in close proximity.

4. The use according to any one of Claims 1 to 3 wherein the pendant carboxylic acid groups are located on adjacent carbons on the polymeric backbone.

5. The use according to any one of Claims 1 to 4 wherein the water-absorbent material is in fibrous form.

6. The use according to any one of Claims 1 to 5 wherein the water-absorbent composition is a copolymer of from about 25 to about 75 mole percent recurring units of at least one ~,.beta.-unsaturated monomer having at least one carboxylic acid group and from about 75 to about 25 mole percent recurring units of at least one copolymerizable monomer.

7. The use according to Claim 6 wherein the ~,.beta.-unsaturated monomer is selected from the group consisting of maleic acid, crotonic acid, fumaric acid, mesaconic acid, the sodium salt of maleic acid, the sodium salt of 2-methyl, 2-butene dicarboxylic acid, the sodium salt of itatonic acid, maleamic acid, maleamide, N-phenyl maleimide, maleimide, maleic anhydride, fumaric anhydride; itaconic anhydride, citraconic anhydride; mesaconic anhydride, methyl itaconic anhydride, ethyl maleic anhydride, diethylmaleate, methylmaleate and mixtures thereof.

8. The use according to Claim 6 or 7 wherein the co-monomer is selected from thegroup consisting of ethylene, propylene, isobutylene, C1 to C4 alkyl methacrylates, vinyl acetate, methyl vinyl ether, isobutyl vinyl ether, and styrenic compounds having the formula:

wherein R represents hydrogen or an alkyl group having from 1 to 6 carbon atoms,and wherein the benzene ring may be substituted or unsubstituted.

9. The use according to any one of Claims 6 to 8 wherein the copolymer is crosslinked with a crosslinking agent selected from monomers having at least two hydroxyl groups such as alkylene glycols containing 2-10 carbon atoms and their ethers, cycloalkylene glycols, Bisphenol A, hydroxy alkylene derivatives of Bisphenol A, hydroquinone,phloroglucinol, hydroxy alkylene derivatives of diphenols, glycerols, erythritol, pentaerythritol, and mono-, di- or oligosaccharides; heterocyclic carbonates; and monomers containing at least one amine group and at least one hydroxyl group such as ethanolamine, tris (hydroxymethyl)aminomethane, 3-amino-1-propanol, DL-1-amino-2-propanol, 2-amino-1-butanol, N,N-dimethylethanolamine, diisopropanol-amine methyl diethanol amine, triethanol amine and 2-(methylamino)ethanol.

10. The use according to any one of Claims 1 to 9 of a water-absorbent composition in an article of manufacture.

11. The use according to Claim 10 wherein the article of manufacture is selected from the group consisting of disposable diapers, sanitary napkins, tampons, pant liners, adult incontinence pads, coverstock for feminine hygiene products, surgical and dentalsponges, bandages, patient underpads, wipes, domestic wipes, industrial wipes, packaging, filters, medical tray pads, fenestration drapes, operating gowns; mortuary pads, other medical related devices, casket liners, forensic examination pads, cable wrap, food tray pads, food preservation articles, seed germination pads, capillary mats, baby bibs, desiccant strips for anti-rust use, bath mats, sorbents, breast pads, underarm pads, wound covers, pet litter, roofing materials, automotive trim, furniture, bedding, clothing, soil modifiers, spill control materials; waste management materials and protective articles.