WO1998016308A1 - Composite materials - Google Patents

Abstract

The present invention relates to composite materials made of inorganic minerals and polymer gels and the application thereof.

Description

Composite materials

description

The present invention relates to composite materials made of inorganic minerals and polymer gels and their use.

Composite materials made from inorganic minerals and naturally occurring organic polymers are known and widely used in nature. They include e.g. Shellfish shells, coral reefs, snail shells, egg shells, bones, teeth and antlers. Shellfish and mother-of-pearl e.g. are natural composite materials that consist of 95 to 99% by weight of calcium carbonate and 1 to 5% by weight of proteins and chitin. These composites, also known as bio-minerals, are notable for their hardness and strength, but are not brittle, while synthetic inorganic solids generally also have an undesirable brittleness in addition to their hardness, which leads to breakage of the materials when impacted.

The production of various composite materials from inorganic salts and some conventional polymers is known. For example, in the Journal of Applied Polymer Science, Vol. 56, 687-695 (1995) and Mater. Res. Soc. Symp.Proc. (1994), 351, 245-50 describe the production of composites from calcium carbonate and chitosan by means of biomimetic production. A film made of chitosan is used as the organic matrix, which is treated with polyacrylic acid with a molecular weight of about 2000.

Nippon Gomu Kyokaishi (1979), 52 (11), 707-12, CA 92: 59617 describes the preparation of polyacrylamide-calcium carbonate composites, wherein Ca (OH) _{2 is} reacted with polyacrylamide in aqueous solution and the reaction product subsequently with CO _{2 is} carbonized in an autoclave. The composite material obtained has good mechanical properties.

JP-A-55124-651 describes the production of composites from CaC0 ₃ and plastic films or synthetic papers by carbonizing Ca (OH) ₂ with C0 ₂ in the presence of polymers of isobutene and maleic anhydride.

JP-A-54149-399 describes the production of cubic CaC0 ₃ by crystallization from Ca (OH) ₂ and C0 ₂ in the presence of polyacrylic acids and other additives, such as, for example, alkali metal chlorides. -carbonates, -hydrogencarbonates and glycerol and a water-soluble saccharide.

JP-A-53002-557 describes the preparation of an aqueous 5 CaC0 ₃ dispersion with a solids content of 40 to 70% by weight by reaction of Ca (OH) ₂ and C0 ₂ in a solution of polyacrylic acid with a molecular weight of about 9000 or an alkali salt thereof.

10 In J.Cryst. Growth (1990), 99 (1-4, Part 2), 1124 ff., The influence of various polymeric additives, such as, for example, polyacrylic acids, polystyrene sulfonates and methacrylic acid-styrene sulfonate copolymers, on the crystallization of CaC0 is described with the aim , the adherence of CaC0 ₃ to cotton, a disadvantage of detergent

15 gentas based on soda.

In Tenside, Sufactants, Detergents, (1994), 31 (1), 12-17, the production of calcium carbonate from calcium chloride and sodium hydrogen carbonate in the presence of control agents, such as e.g. 20 sodium hexamethaphosphate or various polymers, such as polyacrylic acid with a molecular weight of 800 to 20,000, sulfo-containing polymers, polymaleic acids and polyacrylamides.

25 In J.Cryst. Growth, (1994), 137 (3-4), 577-84, the influence of polymers with charged groups, e.g. Polyaspartates, polyglutamates, polyacrylates and carrageenans on the crystallization of calcite and specifically the substitution of calcium by magnesium are described.

30

In mater. Res. Soc. Symp.Proc. (1994), 330, the influence of polyaspartate, polyglutama, polyacrylate and polymaleate on the crystallization of CaC0 ₃ and especially the conversion of vaterite to calcite is described.

35

JP-A-93-175717 describes a process for the preparation of calcite by carbonization of Ca (OH) ₂ in the presence of polymers or copolymers from unsaturated carboxylic acids.

40 Colloid Surf., A (1995), 100, 117 ff. Describes the deposition of CaC0 on glass and cellophane with and without retention aids, such as polyacrylamide and polyethyleneimine.

H. Kawaguchi et al. describe in Colloid Poly. Be. (1992), 45 270 (12), 1176-81 the crystallization of CaC0 ₃ from Na ₂ C0 ₃ and Ca (N0 ₃ ) ₂ in the presence of polystyrene sulfonates. In none of these publications is the composite material based on a polymer gel.

The object of the present invention is to provide new composite materials with improved properties.

Surprisingly, it has now been found that the object is achieved if the composite materials comprise a polymer gel and an inorganic salt or mineral.

The invention therefore relates to composite materials comprising A) at least one water-swellable polymer gel, B) at least one electroneutral compound which comprises one or more cations (s) and one or more anion (s) (the charges of the cations and anions being different compensate each other so that the connection is electroneutral), as well as other components if necessary.

The composite materials according to the invention contain at least one water-swellable polymer gel A). Suitable polymer gels A) are gels with limited swellability. It can be natural polymer gels, especially based on carbohydrates or proteins. Suitable carbohydrates are e.g. cross-linked starch and cellulose and derivatives thereof. Suitable crosslinking agents are diols, such as ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol, polypropylene glycol, etc., dialdehydes, such as glutaraldehyde, epichlorohydrin, etc.

The carbohydrates can also be chemically modified, e.g. by alkylation, hydroxyalkylation, carboxyalkylation. Examples of chemically modified carbohydrates are methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl methyl cellulose etc., all of which are commercially available.

Suitable proteins are e.g. Casein, gelatin, collagen etc. The proteins can be cross-linked, e.g. with dialdehydes, such as glutaraldehyde, or epichlorohydrin.

The preferred polymer gels are those on a synthetic basis, which can be crosslinked or uncrosslinked and which can also contain polymer gels on a natural basis. The synthetic polymer gels are polymers made from at least one ethylenically unsaturated monomer. In order to obtain a water-swellable polymer gel, there is at least one monomer with a hydrophilic one Polymerized group or one of the above carbohydrates is grafted with an ethylenically unsaturated monomer. The hydrophilic group can be an acidic or basic group, preferably a carboxyl or amino group. The acidic group can be partially or completely neutralized with a base, such as an alkali metal (NaOH, KOH) or ammonium hydroxide or an amine, for example triethylamine, mono-, di- or triethanolamine. The basic group can be partially or completely neutralized with an acid, such as HC1, H ₂ SO ₄ , HP0 _4, etc., or quaternized with an alkylating agent which may also have substituents in the alkyl group, such as the hydroxyl group.

Suitable polymer gels are e.g. So-called superabsorbers, which have a absorption capacity of up to 200 times their weight when swollen in liquids, such as water, without losing their geometric shape. The polymer gels can have any regular or irregular shapes or can be applied to carrier materials. According to a special embodiment, these gels can be foam-shaped.

Furthermore, highly swellable gels are also suitable as polymer gels A), which lose their shape when swollen in liquids and change into a colloidal state. Such gels are e.g. in EP-B-0 412 388 and are described inter alia in used as a thickener in textile printing, for thickening paper coating slips or for thickening aqueous paint dispersions.

Polymer gels A, in particular of the superabsorber type, are preferably prepared by polymerizing a mixture (Ml) which a) contains at least one monomer with a hydrophilic group, in particular a water-soluble, monoethylenically unsaturated monomer, b) optionally contains a crosslinker with at least one two non-conjugated, ethylenically unsaturated double bonds, c) optionally at least one additional, copolymerizable, water-insoluble monoethylenically unsaturated monomer, d) at least one polymerization initiator, e) optionally at least one polymerization regulator and, if appropriate, further constituents, in water or a water-containing solvent mixture. Component a):

Suitable monomers a) are, for example, monoethylenically unsaturated C ₃ -C ₂₅ -carboxylic acids or anhydrides, preferably C ₃ - to C _β -carboxylic acids and their amides and esters with amino alcohols of the formula

wherein

A is an alkylene radical with 2 to 5 carbon atoms, R ¹ , R ² and R ³ independently of one another are hydrogen, methyl, ethyl and propyl and X® is an anion.

Further suitable monomers a) are amides of the aforementioned carboxylic acids, which are derived from amines of the formula

derive, wherein A, R ¹ , R ² , R ³ and X® have the same meaning as in formula I.

The monomers a) are then, for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, acrylamide, methacrylamide, crotonic acid amide, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylamino neopentylacrylate and dimethylaminoethyl methacrylate, dimethyl aminophenyl methacrylate, dimethyl methacrylate . The basic acrylates and methacrylates or basic amides, which are derived from the compounds of the formula II, are used in the form of their salts with strong mineral acids, sulfonic acids or carboxylic acids or in quaternized form. The Anion X® then stands for the acid residue of the mineral acids or carboxylic acids or for a methosulfate, ethosulfate or halide from a quaternizing agent.

Other suitable water-soluble monomers (a) are N-vinylpyrrolidone, N-vinylformamide, monoethylenically unsaturated sulfonic acids, such as, for example, vinylsulfonic acid, allylsulfonic acid, vinylphosphonic acid, vinyl lactic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate 3, 2-hydroxyl methacrylate, 2 acryloxy propylsulfonic acid, 2-hydroxy-3-methacryloxypropylsulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, vinylphosphonic acid, vinylphosphoric acid and allylphosphonic acid.

The acid groups of the abovementioned acids can be used in the polymerization either in non-neutralized form or in partially or up to 100% neutralized form.

Other suitable water-soluble monomers of group (a) are also diallylammonium compounds, such as dimethyldiallylammonium chloride, dimethyldiallylammonium bromide, diethyldiallylammonium chloride, and methyl-tert. -butyldiallyla monium methosulfate, methyl-n-propyldiallylammonium chloride, dimethyldiallylammonium hydrogen sulfate, dimethyldiallylammonium dihydrogenphosphate, di-n-butyldiallylammonium bromide, diallylpiperidinium bromide, diallylpyrrolididium bromide. N-vinylimidazolium compounds of the formula are also suitable

in the

R ¹ = H, CH ₃ , C ₂ H ₅ , n- and iC ₃ H ₇ , C ₆ H ₅ and

X ^{~ is} an acid residue. X- preferably represents Cl ^~ , Br ^~ , S0 ₄ ^2_ , HS0 ₄ Θ, H ₂ P0 ₄ Θ, CH ₃ 0-S0 ₃ -, C ₂ H ₅ -O-SO ₃ -, R ⁱ -COCT and R ² = H, Ci- to C ₄ alkyl and aryl.

Examples are N-vinylimidazoline, l-vinyl-2-methylimidazoline, l-vinyl-2-ethylimidazoline or l-vinyl-2-n-propylimidazoline, which are used in quaternized form or as a salt for the polymerization, if desired.

Preferred monomers of group (a) are acrylic acid, methacrylic acid, acrylic id, methacrylamide, vinylsulfonic acid, acrylamido propanesulfonic acid, dimethylaminoethyl acrylate in quaternized form or as a salt, and mixtures of the monomers. These monomers can be copolymerized with one another in any ratio, particularly preferably using partially neutralized acids. Preferably used as monomers a) acrylic acid and / or methacrylic acid; (Meth) acrylic acid / styrene; (Meth) acrylic acid / ester of (meth) acrylic acid with C 1 -C ₄ alkanols, for example n-butyl acrylate;

(Meth) acrylic acid / vinyl ester of Ci-C _ß- alkane carboxylic acids, for example vinyl acetate; (Meth) acrylic acid / N-vinyl lactams, for example N-vinyl pyrolidone; (Meth) acrylic acid / proteins, eg casein; Esters of

(Meth) acrylic acid with Cχ-C ₄ alkanols, for example n-butyl acrylate / starch; Styrene / starch; (Meth) acrylic acid / polyethylene or polypropylene glycol. Some or all of the (meth) acrylic acid can be present as a salt.

Further preferably used monomer mixture a) are e.g. Acrylic acid and / or alkali acrylate / methacrylic acid, acrylic acid / alkali acrylate, acrylic acid and / or alkali acrylate / acrylamidopropanesulfonic acid, acrylic acid and / or alkali acrylate / vinyl sulfonic acid,

Acrylic acid and / or alkali acrylate / acrylamide, acrylamide / dimethylaminoethyl acrylate methochloride, etc.

Component b):

To prepare crosslinked polymers A), the mixture (M1) contains at least one crosslinker b) with at least two non-conjugated, ethylenically unsaturated double bonds. Suitable crosslinkers are, for example, N, N '-methylene-bisacrylamide, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates, which are each derived from polyethylene glycols with a molecular weight of 126 to 8500, preferably 400 to 2000, trimethylol-propane triacrylate, trimethylolpropane trimethacrylate, ethylene glycol, diacrylyl diacrylate, Butanediol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, diacrylates and dimethacrylates of block copolymers made from ethylene oxide and propylene oxide, polyhydric alcohols esterified twice or three times with acrylic acid or methacrylic acid, such as glycerol or pentaerythritol, triallyl amine, diethylenediol ethylenediol, ethylenediethylenediol, tetraallyl ethylenediole diol ethylenediethlyol ethylenediol of polyethylene glycols with a molecular weight of 126 to 4000, trimethylol propanediallyl ether, butanediol divinyl ether, pentaerythritol triallyl ether and / or divinyl ethylene urea.

Water-soluble crosslinking agents are preferably used, for example N, N'-methylene-bisacrylamide, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates which are derived from addition products of 2 to 400 mol of ethylene oxide to 1 mol of a diol or polyol, vinyl ethers of addition products of 2 to 400 mol Ethylene oxide in 1 mole of a diol or polyol, ethylene glycol diacrylate, ethylene glycol dimethacrylate or triacrylates and trimethacrylates of addition products of 6 to 20 moles of ethylene oxide to one mole of glycerol, pentaerythritol triallyl ether and / or divinyl urea.

Compounds which contain at least one polymerizable ethylenically unsaturated group and at least one further functional group are also suitable as crosslinking agent b). The functional group of these crosslinkers must be able to react with the functional groups, essentially the carboxyl groups or sulfonic acid groups of the monomers a). Suitable functional groups are e.g. Hydroxyl, amino, epoxy, isocyanate, ester, amide and aziridino groups.

Also suitable as crosslinking agents b) are compounds which carry at least two of the aforementioned functional groups and which can react with carboxyl and sulfonic acid groups of the monomers a). Examples of such crosslinkers b) are ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerol, polyglycerol, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, block copolymers of ethylene oxide and propylene oxide, sorbitan fatty acid ester, ethoxylated ethyl ester, ethoxylated sorbitol, ethoxylated sorbitol, ethoxylated sorbitan, ethoxylated sorbitan, ethoxylated sorbitol, Pentaerythritol, polyvinyl alcohol, sorbitol, polyglycidyl ethers such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether,

substance-sorbitol, pentaerythritol polyglycidyl ether, propylene lenglykoldiglycidylether and polypropylene glycol diglycidyl ether, polyaziridine compounds such as 2, 2-Bishydroxymethylbutanol- tris [3- (l-aziridinyl) propionate], 1, 6-Hexamethylendiethylenharn-, diphenylmethane-bis-4, 4 '-N, N '-diethyleneurea, halogen epoxy compounds such as epichlorohydrin and α-methylfluorohydrin, polyisocyanates such as 2, 4-tolylene diisocyanate and hexamethylene diisocyanate, alkylene carbonates such as 1, 3-dioxolan-2-one and 4-methyl-1, 3-dioxolane 2-one, polyquaternary amines such as condensation products of dimethylamine with epichlorohydrin, homo- and

Copolymers of diallyldimethyla monium chloride and homopolymers and copolymers of dimethylaminoethyl (meth) acrylate, which are optionally quaternized with, for example, methyl chloride.

Other suitable crosslinkers b) are polyvalent metal ions which are able to form ionic crosslinks. Examples of such crosslinkers are magnesium, calcium, barium and aluminum ions. These crosslinkers are added, for example, as hydroxides, carbonates or hydrogen carbonates to the aqueous polymerizable solution. Other suitable crosslinkers are multifunctional bases which are also able to form ionic crosslinks, for example polyamines or their quaternized salts. Examples of polyamines are ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and polyethyleneimines as well as polyvinylamines with molecular weights of up to 4,000,000 each.

The aforementioned crosslinkers b) can be used individually or in mixtures.

The monomers b) are used only for the preparation of water-insoluble polymers A), in an amount of 50 ppm or more, corresponding to an amount of 0.001 to 5% by weight, preferably 0.01 to 2.0% by weight .-%, based on the total amount of monomer used in the copolymerization.

Component c):

The swellable polymer gels A) can comprise further water-insoluble, monoethylenically unsaturated monomers c). This is to be understood as meaning other monoethylenically unsaturated monomers which are copolymerizable with the monomers a) and b). These include, for example, the amides and nitriles of mono-ethylenically unsaturated carboxylic acids, e.g. Acrylamide, methacrylamide and N-vinylformamide, acrylonitrile and methacrylonitrile, dialkyldiallylammonium halides such as dirnethyldiallylammonium chloride, diethyldiallylammonium chloride, allylpiperidinium bromide, N-vinylimidazoles such as e.g. N-vinylimidazole, l-vinyl-2-methylimidazole and N-vinylimidazolines such as N-vinylimidazoline, 1-vinyl-2-methylimidazoline, l-vinyl-2-ethylimidazoline or l-vinyl-2-propylimidazoline, if appropriate can be used in the polymerization in the form of the free bases, in quaternized form or as a salt.

Dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate are also suitable. The basic esters are preferably used in quaternized form or as a salt.

Further suitable compounds c) are, for example, vinyl esters of saturated C ₄ -C ₄ -carboxylic acids such as vinyl formate, vinyl acetate or vinyl propionate, alkyl vinyl ethers with at least 2 C atoms in the alkyl group, such as ethyl vinyl ether or butyl vinyl ether, esters of monoethylenically unsaturated C ₃ - to C ₆ -carboxylic acids, for example esters from monohydric Cι ~ to Cig alcohols and acrylic acid, such as, for example, methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, the corresponding esters of methacrylic acid, fumaric acid or maleic acid, half-esters of maleic acid ethyl, eg maleic acid ethyl, for example maleic acid ethyl maleate, for example maleic acid the monoethylenically unsaturated carboxylic acids mentioned, for example 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate, N-vinyl lactams such as N-vinyl pyrrolidone or N-vinyl caprolactam, acrylic acid and methacrylic acid esters, For example, alcohols with 10 to 25 carbon atoms, which have been reacted with 2 to 200 moles of ethylene oxide and / or propylene oxide per mole of alcohol, and monoacrylic acid esters and monomethacrylic acid esters of polyethylene glycol or polypropylene glycol, the molar masses (M _N ) of the polyalkylene glycols for example, can be up to 2000. Other suitable monomers from group c) are alkyl-substituted styrenes such as ethylstyrene or tert. Butyl styrene.

The monomers c) can also be used in a mixture in the copolymerization with the other monomers, e.g. Mixtures of vinyl acetate and 2-hydroxyethyl acrylate in any ratio. If the monomers of group (c) are used to modify the water-soluble or water-insoluble polymers, they are used in particular in amounts of 0.5 to 20, preferably 2 to 10,% by weight, based on the total for the polymerization incoming monomers.

Preferred monomers c) are (meth) acrylamide, (meth) acrylic acid ester, vinyl aromatic compounds and N-vinyl lactams.

Component d):

The monomers a) and optionally b) and optionally c) are polymerized in water or in 10 to 80, preferably 20 to 60% by weight aqueous solution in the presence of polymerization initiators. All compounds which break down into free radicals under the polymerization conditions can be used as polymerization initiators, for example peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and redox catalysts. The use of water-soluble initiators is preferred. In some cases it is advantageous to use mixtures of different polymerization initiators, for example mixtures of hydrogen peroxide and sodium or potassium peroxydisulfate. Mixtures of hydrogen peroxide and sodium peroxydisulfate can be used in any ratio become. Suitable organic peroxides are, for example, acetyl acetone peroxide, methyl ethyl ketone peroxide, tert. -Butyl hydroperoxide, cumene hydroperoxide, tert. -Amyl perpivalate, tert. Butyl perpivalate, tert. Butyl perneohexanoate, tert. Butyl perisobutyrate, tert. -Butyl- per-2-ethylhexanoate, tert. Butyl perisononanoate, tert. Butyl per maleate, tert. Butyl perbenzoate, tert. -Butylper-3, 5, 5-tri-methylhexanoate and tert. -Amylperneodecanoate. Particularly suitable polymerization initiators are water-soluble azo starters, for example 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N '- dimethylene) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutyronitrile, 2,2'-azobis [2- (2'-imidazolin-2-yl) propane] dihydrochloride and 4,4'-azobis (4-cyanovaleric acid). The polymerization initiators mentioned are used in customary amounts, for example in amounts of 0.001 to 5, preferably 0.1 to 2.0,% by weight, based on the monomers to be polymerized.

Redox catalysts can also be used as initiators. Redox catalysts contain at least one of the above-mentioned per-compounds as the oxidizing component and e.g. Ascorbic acid, glucose, sorbose,

Ammonium or alkali metal hydrogen sulfite, sulfite, thiosulfate, hyposulfite, pyrosulfite or sulfide, metal salts such as iron (II) ions or silver ions or sodium hydroxymethyl sulfoxylate. Ascorbic acid or sodium sulfite is preferably used as the reducing component of the redox catalyst. Based on the amount of monomers used in the polymerization, for example 3 ^» 10 ^-6 to 1 mol% of the reducing component of the redox catalyst system and 0.001 to 5.0 mol-% of the oxidizing component of the redox catalyst are used. Instead of the oxidizing component of the redox catalyst, one or more water-soluble azo starters can also be used.

Component e):

The mixture (Ml) can optionally be polymerized in the presence of polymerization regulators e). Suitable regulators are compounds which limit the molecular weight of the polymers in polymerizations, for example alcohols, salts of hydrazine and hydroxylamine, formic acid, alkali and ammonium salts of formic acid, organic compounds which contain sulfur in bound form, such as organic sulfides, disulfides, polysulfides , Sulfoxides, sulfones and mercapto compounds, ammonia and amino or mixtures thereof. Examples of polymerization regulators are: di-n-butyl sulfide, di-n-octyl sulfide, diphenyl sulfide, thiodiglycol, ethyl thioethanol, diisopropyl disulfide, di-n-butyl disulfide, di-n-hexyl disulfide, diacetyl disulfide, diethanol sulfide, di-t-sulfide and dimethyl trisulfide , Ethanolamine, diethanolamine, tri- ethanolamine, triethylamine, morpholine and piperidine. Preferred as

Compounds used in polymerization regulators are mercapto compounds, dialkyl sulfides and / or diarylsulfides. Examples of these compounds are ethylthioglycolate, cysteine, 2-mercaptoethanol, 1, 3-mercaptopropanol, 3-mercaptopropan-l, 2-diol,

1, 4-mercaptobutanol, thioglycolic acid, 3-mercaptopropionic acid,

Mercaptosuccinic acid, thioglycerol, thioacetic acid, thiourea and alkyl mercaptans such as n-butyl mercaptan, n-hexyl mercantan or n-dodecyl mercaptan. Polymerization regulators used with particular preference are isopropanol, formic acid and its alkali metal and ammonium salts, thioglycolic acid and its alkali metal and ammonium salts, and all regulators which have a similarly high transmission constant to thioglycolic acid. The regulators are used in an amount of 0 to 20% by weight, preferably 0 to 10% by weight, based on the total amount of the mixture (Ml).

In the preparation of water-soluble polymers A), the monomers a) described above are polymerized in the absence of monomers b). The monomers of group c) can optionally also be used to modify the water-soluble polymers.

For the production of water-absorbing polymers A), i.e. Polymers which are insoluble in water but swell therein, the water-soluble monoethylenically unsaturated monomers of group a) are polymerized with 0.001 to 5.0% by weight, based on the total amount of monomers used in the polymerization, of at least one crosslinker b). The water-insoluble polymers can optionally also be modified with the monomers of group c).

According to a preferred embodiment, partial polymerization is carried out e.g. acrylic acid neutralized with sodium hydroxide solution, monomer mixtures of acrylamide and acrylic acid and / or sodium acrylate and monomer mixtures of acrylamide and dimethylaminoethylacrylate methochloride. The monomers can be copolymerized with one another in any ratio. It is also possible to polymerize them to homopolymers, e.g. Homopolymers made from acrylamide and homopolymers made from dimethylaminoethyl acrylate methochloride.

The polymerization is carried out in each case in aqueous solution or in solvent mixtures which contain at least 50% by weight of water. Suitable water-miscible solvents are, for example, glycols such as ethylene glycol, propylene glycol and butylene glycol and Polyethylene glycols with a molecular weight up to 4000 as well as methyl and ethyl ethers of glycols and polyglycols.

The person skilled in the art is familiar with carrying out the processes for producing the polymer gels A) of the superabsorber type. The monomers and the initiators are dissolved, for example, in stirred tanks in the aqueous medium used for the polymerization. The initiators can optionally be fed to the reactor in the form of a solution in an organic solvent. The solution of the monomers and the initiators is preferably on a

Temperature set in the range of -20 to 30 ° C. In order to remove residual oxygen from the solution of the monomers and the initiators, an inert gas is usually passed through these solutions. Nitrogen, carbon dioxide or noble gases such as neon or helium are suitable for this. The polymerization is carried out in the absence of oxygen. The solution of the monomers and the initiator are mixed with one another before they reach the reactor, the introduction of monomers and initiator into the tubular reactor preferably taking place in countercurrent to an inert gas. The polymerization can be carried out batchwise and continuously. In a batch operation, for example, the reactor is filled with an aqueous monomer solution and a solution of the initiator. As soon as the polymerization starts, the reaction mixture heats up depending on the starting conditions chosen, such as the concentration of the monomers in the aqueous solution and the type of monomers. Due to the heat of polymerization released, the temperature of the reaction mixture rises to, for example, 30 to 180, preferably 40 to 130 ° C. The polymerization can be carried out under normal pressure, under reduced pressure or under increased pressure. Working under increased pressure can be advantageous in such cases if the temperature maximum to be expected during the polymerization is above the boiling point of the solvent mixture used. On the other hand, it can be advantageous to lower the maximum temperature with the help of evaporative cooling by polymerizing under reduced pressure or by external cooling, especially in the production of very high molecular weight products.

According to a special embodiment, a tubular reactor is used, as described in DE-A-195 029 39.9.

The polymerization takes place adiabatically in discontinuous operation. High-molecular products are obtained by the process according to the invention. The molar masses of the water-soluble products are above 100,000 and are preferably 1 ^» 10 ⁶ to 20» 10 ⁶ . They have Fikentscher K values from 180 to 300 ( agrees in 5% aqueous saline solution at a polymer concentration of 0.1 wt .-% and a temperature of 25 ° C). No K value can be given for the crosslinked polymers because the crosslinked polymers do not dissolve in water or another solvent. A molecular weight determination is not possible for the crosslinked polymers.

According to a particular embodiment, the composite materials according to the invention comprise swellable, show-shaped polymer gels A) (superabsorbers) which are obtainable by

(I) foaming a polymerizable aqueous mixture (M2), the

a) at least one monoethylenically unsaturated monomer containing acid groups, at least 50 mol% of the acid groups being neutralized,

b) optionally a crosslinker with at least two non-conjugated, ethylenically unsaturated double bonds,

c) optionally at least one additional, copolymerizable water-insoluble monoethylenically unsaturated monomer,

d) at least one polymerisation initiator,

e) optionally at least one polymerization regulator,

f) 0.1 to 20% by weight of at least one surfactant,

(g) where appropriate, at least one solubilizer;

h) optionally thickeners, foam stabilizers, fillers and / or cell nucleating agents

and optionally contains further constituents, the foaming being carried out by dispersing fine bubbles of a gas which is inert to free radicals, and

(II) polymerizing the foamed mixture to form a foam hydrogel and adjusting the water content of the foam polymer to 1 to 45% by weight.

Suitable monomers a) for producing foam-like polymer gels A) are the abovementioned monoethylenically unsaturated monomers a) containing acid groups, such as monoethylenically unsaturated C ₃ -C ₂₅ -carboxylic acids or anhydrides, monoethylenically unsaturated Tigt sulfonic acids, vinyl phosphoric acid and allylphosphonic acid, or mixtures thereof.

Preferred monomers a) for producing foam-like superabsorbers are acrylic acid, methacrylic acid, vinylsulfonic acid, acrylamidopropanesulfonic acid, or mixtures thereof.

The monomers a) are neutralized to at least 50 mol%, preferably to 65 mol%. The bases mentioned above are used for neutralization, preferably sodium hydroxide solution or potassium hydroxide solution.

The above-mentioned components b) are suitable crosslinkers b) for the production of foam-like polymers A).

In a preferred embodiment of the invention, two different crosslinkers are used, one of which is water-soluble and the other of which is water-insoluble. The hydrophilic crosslinker, which is soluble in the aqueous phase of the reaction mixture, conventionally brings about a relatively uniform crosslinking of the resulting polymer, as is customary in the production of a superabsorbent. The hydrophobic crosslinking agent, which is insoluble or only sparingly soluble in the polymerizable aqueous mixture, accumulates in the surfactant boundary layer between the gas phase and the polymerizable aqueous phase. As a result, the surface of the foam is crosslinked more than the inner part of the superabsorbent hydrogel in the subsequent polymerization. A core-shell structure of the foam is thereby obtained directly during the production of the super absorber foam. Such a strong superficial crosslinking of a superabsorbent foam is only possible in the known production processes of the prior art by subsequently crosslinking a foam-like superabsorbent that has already been formed on the surface. For this post-crosslinking, a separate process step is necessary in the conventional mode of operation, which can be omitted in the method of the present invention.

Products according to the invention with a core-shell structure show significantly improved properties compared to homogeneously cross-linked samples with regard to the uptake rate, distribution effect and gel stability. With the exception of polyvalent metal ions, all of the water-insoluble crosslinkers described above, which can be assigned to the different groups, are suitable for producing foams with a core-shell structure, that is to say foams in which the entire surface is more strongly crosslinked than the underlying layer was referred to above as the core layer. Particularly preferred hydrophobic crosslinkers are diacrylates or dimethacrylates or divinyl ethers of alkanediols with 2 to 25 C atoms (branched, linear, with any arrangement of the OH groups), such as 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, neopentylglycol, 1, 9-nonanediol or 1,2-dodecanediol, di-, tri- or polypropylene glycol diacrlyate or dimethacrylate, allyl acrylate, allyl methacryla, divinylbenzene, glycidyl acrylate or glycidyl methacrylate, allyl glycidyl ether and bisglycidyl ether of the alkane listed above.

Suitable hydrophilic crosslinkers are, for example, N, N '-methylene bisacrylamide, polyethylene glycol diacrylates or dimethacrylates with a molecular weight M _N of 200 to 4000, dinvinylurea, triallylamine, diacrylates or dimethacrylates of addition products of 2 to 400 moles of ethylene oxide with 1 mole of a diol or polyol or the triacrylate of an addition product of 20 moles of ethylene oxide with 1 mole of glycerol and vinyl ether of addition products of 2 to 400 moles of ethylene oxide with 1 mole of a diol or polyol.

The polymerizable aqueous mixture (M2) may optionally contain the aforementioned monoethylenically unsaturated monomers c) which are copolymerizable with the monomers a) and b).

The monomers a) are present in the polymerizable aqueous mixture (M2), for example in amounts of 10 to 80 and preferably 20 to 60% by weight. The monomers c) are only used, if appropriate, for modifying the superabsorbent foams and can be present in the polymerizable aqueous mixture in amounts of up to 50, preferably in amounts of up to 20,% by weight. The crosslinkers (c) are present in the reaction mixture, for example from 0.001 to 5 and preferably from 0.01 and 2% by weight.

Suitable initiators for initiating the polymerization of the mixture (M2) for producing foam-like polymers A) are all initiators which form free radicals under the polymerization conditions, in particular the above-mentioned initiators. It is also possible to initiate the polymerization by the action of electron beams on the polymerizable, aqueous mixture. The polymerization can also be initiated in the absence of initiators of the type mentioned above by exposure to high-energy radiation in the presence of photoinitiators.

For polymerization by the action of high-energy radiation, so-called photoinitiators are usually used as initiators. These can be, for example, so-called α-splitters, H-abstracting systems or also azides. Examples of such initiators are benzophenone derivatives such as Michlers ketone, phenanthrene derivatives, fluorene derivatives, anthraquinone derivatives, thioxanone derivatives, coumarin derivatives, benzoin ethers and their derivatives, substituted azo compounds such as the radical formers mentioned above Hexaarylbisimidazole or acylphosphine oxides. Examples of azides are: 2- (N, N-dimethylamino) ethyl 4-azidocinnamate, 2- (N, N-dimethylamino) ethyl-4-azidonaphthyl ketone, 2- (N, N-dimethylamino) -ethyl-4-azidobenzoate, 5-azido-l-naphthyl-2 '- (N, N-dimethylamino) ethylsulfone, N- (4-sulfonyl azidophenyl) maleimide, N-acetyl-4-sulfonyl azidoaniline, 4-sul- fonylazidoaniline, 4-azidoaniline, 4-azidophenacyl bromide, p-azide-topzoic acid, 2,6-bis (p-azidobenzylidene) cyclohexanone and 2,6-bis (p-azidobenzylidene) -4-methylcyclohexanone. If they are used, the photoinitiators are usually used in amounts of from 0.01 to 5% by weight, based on the monomers to be polymerized.

In order to vary the properties of the foams, for example the rate of absorption and the capacity of water, it may be advantageous to add a polymerization regulator e) or a mixture of several polymerization regulators to the aqueous reaction mixture. Suitable polymerization regulators are those mentioned above. The amounts of polymerization regulator e) can be up to 10% by weight, preferably 0.1 to 5% by weight, based on the monomers used.

The polymerizable aqueous mixtures (M2) contain as component f) 0.1 to 20% by weight of at least one surfactant. The tensides are of crucial importance for the production and stabilization of the foam. Anionic, cationic or nonionic surfactants or surfactant mixtures which are compatible with one another can be used. Low-molecular or polymeric surfactants f) can be used, combinations of different or similar types of surfactants having proven to be advantageous.

Suitable nonionic surfactants f) are, for example, addition products of alkylene oxides, in particular ethylene oxide, propylene oxide and / or butylene oxide with alcohols, amines, phenols, naphthols or carboxylic acids. Addition products of ethylene oxide and / or propylene oxide with alcohols containing at least 10 carbon atoms are advantageously used as surfactants, the addition products containing 3 to 200 moles of ethylene oxide and / or propylene oxide per mole of alcohol. The addition products contain the alkylene oxide units in the form of blocks or in a statistical distribution. In particular, nonionic surfactants f) are, for example, addition products of 7 mol of ethylene oxide with 1 mol of tallow fatty alcohol, Additions of 9 moles of ethylene oxide to 1 mole of tallow fatty alcohol and addition products of 80 moles of ethylene oxide to 1 mole of tallow fatty alcohol are used. Further suitable commercially available nonionic surfactants include reaction products of oxo alcohols (isomer mixture of higher alcohols obtained by oxo synthesis) or Ziegler alcohols (primary, linear Cχo to C ₂₂ alcohols, obtained by oligomerization of ethylene and subsequent oxidation after the Ziegler-Alfol process) with 5 to 12 moles of ethylene oxide per mole of alcohol, in particular with 7 moles of ethylene oxide. Further suitable commercially available nonionic surfactants f) are produced by ethoxylating castor oil. For example, 12 to 80 moles of ethylene oxide are added per mole of castor oil. Preferred nonionic surfactants f) are, for example, the reaction products of 18 moles of ethylene oxide with 1 mole of tallow fatty alcohol, the addition products of 10 moles of ethylene oxide with 1 mole of a C ₃ / Ci ₅ oxo alcohol, or the reaction products of 7 to 8 moles of ethylene oxide with 1 mole a Cι ₃ / Ci ₅ oxo alcohol. Other suitable nonionic surfactants f) are phenol alkoxylates such as p-tert. -Butylphenol with 9 moles of ethylene oxide or methyl ether of reaction products from 1 mole of a -C ₂ - to cig alcohol and 7.5 moles of ethylene oxide.

Suitable anionic surfactants f) are, for example, alkali metal or ammonium salts of sulfuric acid semiesters of addition products of ethylene oxide and / or propylene oxide with fatty alcohols, alkali metal or ammonium salts of alkylbenzenesulfonic acid or of alkylphenol ether sulfates. The nonionic surfactants f) described above can be converted into the corresponding sulfuric acid semiesters, for example by esterification with sulfuric acid. Suitable anionic surfactants f) are commercially available. These include, for example, the sodium salt of a sulfuric acid half ester of a C ₁₃ / Ci ₅ oxo alcohol reacted with 106 mol of ethylene oxide, the triethanolamine salt of dodecylbenzenesulfonic acid, the sodium salt of alkylphenol ether sulfates and the sodium salt of the sulfuric acid half ester of a reaction product of 106 mol of ethylene oxide with 1 mol. Other suitable anionic surfactants f) are sulfuric acid semiesters of C 1 -C ₅ -oxoalcohols, paraffin sulfonic acids such as, for example, cis-alkyl sulfonate, alkyl-substituted benzenesulfonic acids and alkyl-substituted naphthalenesulfonic acids such as dodecylbenzenesulfonic acid and di-n-butyl cephalophosphate alcohol, such as fatty alcohol cephalophosphate alcohol, . The polymerizable aqueous mixture (M2) can contain combinations of a nonionic surfactant and an anionic surfactant or combinations of several nonionic surfactants or combinations of several anionic surfactants. Examples of suitable cationic surfactants f) are, for example, the reaction products of 6.5 mol of ethylene oxide quaternized with dimethyl sulfate and 1 mol of oleylamine, distearyldimethylammonium chloride, lauryltri methylammonium chloride, cetylpyridinium bromide and stearic acid triethanolamine ester quaternized with dimethyl sulfate.

The surfactant content of the polymerizable aqueous mixture (M2) is 0.1 to 20% by weight, preferably 0.5 to 10% by weight, in particular 1.5 to 6% by weight.

The polymerizable aqueous mixtures can optionally contain at least one solubilizer as component g). Suitable solubilizers g) are water-miscible organic solvents, such as e.g. Alcohols, glycols, polyethylene glycols and monoethers derived therefrom, the monoethers, e.g. Methyl glycol, butyl glycol, butyl diglycol, methyl diglycol, butyl triglycol, 3-ethoxy-l-propanol and glycerol monomethyl ether.

The polymerizable aqueous mixtures (M2) contain 0 to 50% by weight, preferably 0 to 25% by weight, of at least one solubilizer g).

The polymerizable aqueous mixture may optionally contain further components h), such as e.g. Contain thickeners, foam stabilizers, fillers and cell nucleating agents. Thickeners are used, for example, to optimize the foam structure and to improve foam stability. It is achieved that the foam shrinks only slightly during the polymerization. All known natural and synthetic polymers which greatly increase the viscosity of an aqueous system can be considered as thickeners. These can be water-swellable or water-soluble synthetic and natural polymers. Powdered superabsorbers A) are also suitable as thickeners. Suitable thickeners h) are e.g. by R.Y. Lochhead and W.R. Fron in Cosmetics & Toiletries, 108, 95-135 (May 1993) and by M.T. Clarke, "Rheological Additives" in D. Laba (ed.) "Rheological Properties of Cosmetics and Toiletries", Cosmetic Science and Technology Series, Vol. 13, Marcel Dekker Inc., New York 1993.

Suitable thickeners h) are, for example, high molecular weight polymers of the monoethylenically unsaturated monomers containing acid groups described above under a), such as homopolymers of acrylic acid and / or methacrylic acid or slightly crosslinked copolymers of acrylic acid and / or methacrylic acid and a crosslinking agent which contains at least 2 ethylenically unsaturated Contains double bonds, such as butanediol diacrylate. High molecular weight polymers of acrylamide and methacrylamide or copolymers of acrylic acid and acrylamide with molecular weights of more than 1,000,000 are also suitable. High molecular weight are also suitable Polyethylene glycols or copolymers of ethylene glycol and propylene glycol, as well as high molecular polysaccharides such as starch, guar gum, locust bean gum or derivatives such as carboxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, hydroxypropyl cellulose and mixed cellulose ether. Other suitable thickeners h) are water-insoluble products, such as, for example, finely divided silicon dioxide, pyrogenic silicas, precipitated silicas in hydrophilic or hydrophobic modifications, zeolites, titanium dioxide, cellulose powder, or other finely divided powders of crosslinked polymers other than superabsorbents. The polymerizable aqueous mixtures (M2) can contain the thickeners in amounts of 0 to 30% by weight, preferably 0.5 to 20% by weight.

The polymerizable aqueous mixture (M2) may further contain foam stabilizers h) in order to optimize the foam structure. Suitable foam stabilizers g) are e.g. Hydrocarbons with at least 5 carbon atoms in the molecule, e.g. Pentane, hexane, cyclohexane, heptane, octane, isooctane, decane and dodecane. Suitable aliphatic hydrocarbons can be straight-chain, branched or cyclic and have a boiling temperature which is above the temperature of the aqueous mixture (M2) during foaming. The aliphatic hydrocarbons increase the service life of the as yet unpolymerized, foamed aqueous reaction mixture. The hydrocarbons are used in an amount of 0 to 10% by weight, preferably 0.1 to 5% by weight, based on the weight of the polymerizable aqueous mixture (M2).

The components h) can be used individually or in a mixture in the preparation of the polymers A) according to the invention.

The foam-like polymer gels A) used in the composite materials according to the invention are produced in two process stages. The polymerizable aqueous mixture (M2) described above is foamed in a first process step. For this purpose, an inert gas in the form of fine bubbles is dispersed in the aqueous monomer phase in such a way that a foam is formed. Gas bubbles can be introduced into the monomer mixture, for example, with the aid of whipping, shaking, stirring or whipping devices or by the gases flowing out of a liquid-covered opening or by exploiting turbulence in currents and by forming lamellae on wires or sieves. The different methods can possibly be combined with each other. Suitable gases which are inert to radicals are, for example, Substance, carbon dioxide, helium, neon and argon. Nitrogen is preferably used.

Apparatus for the production of foams are known to the person skilled in the art and are e.g. by Frisch and Saunders in Polymeric Foams Part II, pp. 679ff (1973).

To produce the foam, which is carried out in a conventional manner, all components of the reaction mixture are combined. Appropriately, the procedure is to first dissolve all the water-soluble components in water and only then to add the water-insoluble substances. Depending on the method used to generate the whipped foam and the initiator contained in the polymerizable aqueous mixture, it may also be advantageous to add the initiator to the mixture only at the end of the whipping process. The consistency of the whipped foams can be varied in a wide range. This makes it possible to produce light, flowable foams or rigid, cut-resistant foams. Likewise, the average size of the gas bubbles, their size distribution and their arrangement in the liquid matrix can be varied within a wide range by the selection of the surfactants, the solubilizers, thickeners and foam stabilizers, cell nucleating agents, the temperature and the whipping technique, so that density can be achieved in a simple manner , Open cell or wall thickness of the matrix material. The temperatures of the polymerizable aqueous mixture during the foaming process are in the range from -10 to 100, preferably 0 to + 50 ° C. In any case, temperatures which are below the boiling point of constituents of the polymerizable aqueous mixture are used in the production of foam. Foam production can also take place under increased pressure, e.g. at 1.5 to 25 bar. However, work is preferably carried out under atmospheric pressure.

Advantageously, foamed, polymerizable aqueous mixtures (M2) are obtained which are stable over a longer period, for example up to 6 hours. The foam-free mixtures (M2) which have not yet been polymerized can, for example, be brought into a suitable shape for the subsequent polymerization in order to produce the shaped articles desired for a particular application. The waste foam which may arise during the shaping of the foamed polymerisable aqueous mixture (M2) can easily be returned to the process. The foamed polymerizable material can, for example, be applied in the desired thickness to a temporary carrier material which is advantageously provided with a non-stick coating. You can, for example, the foam roll up a pad. Another possibility is to fill the polymerizable, foam-like aqueous mixture into molds which are also non-stick coated and which

Polymerize foam in it.

As described further below, the material coated with the polymer gel can be provided with a coating of a composite material based on this gel. For this, e.g. the foam obtained after the generation of the whipped foam, which is yet to be polymerized, or the already polymerized foam is applied to a carrier material, such as films made of polymers (eg films made of polyethylene, polypropylene or polyamide) or metals, nonwovens, fluff, tissues, fabrics, natural or synthetic Fibers, or other foams. According to a preferred embodiment, the foam can be applied to a carrier material in the form of certain structures or in different layer thicknesses. The foamed polymerizable aqueous mixture (M2) obtainable in the first process step can also be shaped and polymerized into large blocks. After the polymerization, the blocks can be cut or sawn into smaller shaped bodies. Sandwich-like structures can also be produced by applying a foamed polymerizable aqueous mixture (M2) in layers which are interrupted by the aforementioned carrier materials.

In the second process stage for the production of the foam-like superabsorbers A), the foamed polymerizable aqueous mixture (M2) is polymerized. Depending on the initiator used, the polymerization can be carried out by increasing the temperature, by exposure to light, by irradiation with electron beams or by increasing the temperature and exposure to light. In order to increase the temperature of the foamed polymerizable aqueous mixture, all methods customary in the art can be used, for example bringing the foam into contact with heatable plates, exposure to infrared radiation on the polymerizable foam or heating with the aid of microwaves. If thicker layers of foam are to be produced, e.g. Foams with a thickness of several centimeters, the heating of the polymerizable foamed material with the aid of a microwave is particularly advantageous, because in this way a relatively uniform heating can be achieved.

The polymerization then takes place, for example, at a temperature of 20 to 180 ° C., preferably 20 to 100 ° C. When the polymerization is initiated by the action of light on the foamed polymerizable material, all conventional imagesetter systems can be used, provided their emission spectrum is adapted to the photoinitiator used. When the polymerization is started by exposure, it is advantageous to use a combination of a photoinitiator of a thermal initiator and / or a photoinitator which can also act as a thermal initiator, for example azo initiators. Since the foam heats up strongly during the polymerization due to the high heat of polymerization, a particularly rapid and effective course of the polymerization reaction is achieved in this way. When initiated by exposure to light, the polymerization temperature is in the range from 0 to 150, preferably 10 to 100 ° C.

Advantageously, the polymerization proceeds with largely maintaining the structure of the foamed polymerizable aqueous mixture, i.e. the polymerizable foam changes its volume only slightly during the polymerization. The polymerization reaction is influenced by the start temperature, the initiation technology or the heat dissipation. The polymerization temperature is chosen so that boiling of the polymerizable aqueous mixture is avoided. As the polymerization progresses, the foam solidifies due to increasing gel formation. After the end of the polymerization, there is a foam-like hydrogel which has a water content of 30 to 80% by weight. The foam has, at least in part, an open-cell structure. For the use of the foam as superabsorbent A), a residual moisture content of 1 to 45, preferably 15 to 35% by weight is desirable. The foam-like hydrogel obtained in the polymerization is therefore generally dried. In order to obtain a flexible foam, the foam must have a certain residual moisture. The water content strongly depends on the density of the foam produced. The higher the density, the more residual moisture has to be set.

Methods for drying the foam are known and include e.g. Heating with a hot gas stream, applying vacuum, infrared radiation or heating with microwave radiation. Microwave radiation is advantageous for drying large-volume molds.

The relatively hard and brittle foam initially obtained can, if desired, be made more flexible with the aid of external plasticizers or by means of internal flexibilization. External plasticizers are, for example, hydrophilic and hygroscopic substances for the targeted adjustment of a certain residual water content. Furthermore, the flexibility can be improved, for example, by using polyols, such as glycerol, polyalkylene glycols, such as polyethylene glycols or polypropylene glycols, or cationic surfactants. Suitable cationic surfactants are described above as component f).

Internal flexibility describes the use of softening components that are built into the gel structure. Suitable substances are those which themselves bear unsaturated groups, such as the aforementioned monomers c) and which are incorporated into the gel structure or react with the gel-forming material. The internal plasticizer is said to lower the glass temperature of the super absorber. Suitable internal plasticizers are, for example, olefins, esters of ethylenically unsaturated C ₃ to Cs carboxylic acids and monohydric C to C ₃ o alcohols or polyethylene glycol or polypropylene glycol monoesters of monoethylenically unsaturated C ₃ to Cs carboxylic acids. Suitable monomers c) for internal flexibilization are those which reduce the glass transition temperature of the copolymers formed with the monomers (a), for example vinyl esters of saturated carboxylic acids with 4 or more carbon atoms, alkyl vinyl ethers with at least 2 carbon atoms in the alkyl group, vinyl lactams and alkyl-substituted styrenes .

As has already been stated above, an inhomogeneous crosslinking density can be generated in the superabsorbent foams according to the invention during production. This is particularly advantageous when used as monomers of the components described above

a) acrylic acid, methacrylic acid, vinylsulfonic acid, acrylamido propanesulfonic acid or mixtures thereof and

b) uses a mixture of at least one water-soluble and at least one water-insoluble crosslinker.

To increase the degree of crosslinking of the foam following the polymerization of the mixture (M2), monomers with chemically reactive groups are used which are stable under the conditions of the radical polymerization in the 1st process stage.

Examples of such monomers are, for example, hydroxyl group-containing monomers which are capable of reacting with carboxyl groups in the foam structure at a higher temperature, for example at temperatures above 150 ° C. Suitable monomers that contain latent have crosslinking sites, for example the crosslinkers b) described above, which contain at least one polymerizable ethylenically unsaturated double bond and at least one further functional group which, for reaction with further functional groups, such as, for example, the carboxyl groups or sulfonic acid groups of the monomers a) described above or the like, or are capable of different crosslinkers b).

Further suitable postcrosslinkers form covalent or ionic bonds with the functional groups of the polymer matrix. Suitable crosslinking agents are e.g. Compounds which have at least two identical or different functional groups, e.g. selected from hydroxyl, amino, quaternary ammonium, isocyanato, epoxy, aziridino, ester or amide groups. Preferred post-crosslinking agents are polyalcohols such as glycerol or bisepoxides. The crosslinking agents can be applied to the foamed material, for example by spraying, dipping or by vapor deposition.

The foam-like superabsorbers A) have a gravimetrically determined density of 10 ^-3 to 0.9 g / cm ³ , preferably 0.05 to 0.7 g / cm ³ .

Suitable polymer gels A) contained in the composite materials according to the invention are also highly swellable gels which lose their shape when swollen in liquids, in particular in water, and change into a colloidal state. As mentioned above, such polymers are e.g. in EP-B-0 412 388. These are finely divided polymer powders which are prepared by polymerizing water-soluble polymers in the aqueous phase of a water-in-oil emulsion in the presence of free radical initiators and corresponding emulsifiers. According to a special embodiment described in EP-B-0 412 388, the polymerization is carried out in the presence of protective colloids or these protective colloids are added to the resulting water-in-oil polymer suspension after the polymerization has ended.

According to a further particular embodiment, strongly swellable polymer gels A) are used which comprise agglomerated polymer particles which disintegrate into the primary particles when introduced into an aqueous medium. Agglomerated polymer particles of water-swellable polymers with an average particle diameter of 20 to 5000 μm are preferably used, the agglomerated polymer particles consisting of primary particles with an average particle diameter of 0.1 to 15 μm and by polymerizing water-soluble monomers in the presence of Regulators and crosslinking agents like a water-in-oil

Polymerization and subsequent azeotropic dewatering of the

Water-in-oil polymer emulsions containing primary particles

Presence of agglomerating polyalkylene glycols

(a) can be obtained by addition of C ₂ - to C ₄ -alkylene oxides onto alcohols, phenols, amines or carboxylic acids, and

(b) contain at least 2 alkylene oxide units in copolymerized form,

are producible.

All (already mentioned) water-soluble ethylenically unsaturated monomers can be used for the production of the agglomerated polymer particles for the production of highly swellable polymer gels A).

The preferred water-soluble ethylenically unsaturated monomers are acrylic acid, methacrylic acid, acrylamide, methacrylamide,

2-Acrylamido-2-methylpropanesulfonic acid, N-vinylimidazole, N-vinyl ~ formamide, hydroxyethyl acrylate, hydroxypropyl acrylate, N-methylol acrylamide or mixtures thereof. The monomers can either be polymerized alone to give homopolymers or polymerized as a mixture with one another to give copolymers. Of particular interest are, for example, copolymers of acrylamide and acrylic acid, copolymers of acrylamide and methacrylic acid, copolymers of methacrylamide and acrylic acid, copolymers of methacrylamide and methacrylic acid, copolymers of acrylamide, acrylic acid and acrylamide-2-methylpropanesulfonic acid, copolymers of acrylamide and dimethylaminoethyl acrylate, copolymers of acrylamide and diethylaminoethyl methacrylate and copolymers of methacrylamide and dimethylaminoethyl acrylate. The carboxylic acids and the other ethylenically unsaturated acids, such as vinylsulfonic acid and acrylamidomethylpropanesulfonic acid, can be used in the polymerization either in the form of the free acid, in partially neutralized or else in completely neutralized form. Bases for neutralizing these monomers are, for example, sodium hydroxide solution, potassium hydroxide solution, ammonia, amines, such as triethylamine, butylamine, triethylamine, morpholine and ethanolamine.

The basic acrylates and methacrylates are preferably used as a salt or in quaternized form in the homo- or copolymerization. The basic acrylates and methacrylates are neutralized, for example, with the aid of hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid and carboxylic acid. such as formic acid, acetic acid and propionic acid. The basic acrylates and methacrylates are also used in quaternized form. The quaternization products are obtained by quaternizing these compounds with customary quaternizing agents, such as methyl chloride, ethyl chloride, benzyl chloride, lauryl chloride, dimethyl sulfate, diethyl sulfate or epichlorohydrin.

The water-soluble monomers can also be polymerized in the presence of crosslinking agents. Suitable crosslinkers are the components b) mentioned above with at least two non-conjugated, ethylenically unsaturated double bonds. Preferably water-soluble crosslinking agents are used, e.g. N, N '-methylene-bis-acrylamide, polyethylene glycol diacrylates, polyethylene glycol dimethacrylates, pentaerythritol triallyl ether and / or divinyl urea. The crosslinking agents are used in an amount of 50 to 5000 ppm, corresponding to approximately 0.003 to 0.3 mol%, based on the monomers used in the polymerization. According to a preferred embodiment, the crosslinking agents are used in an amount of at least 1000 ppm, in particular at least 2000 ppm, preferably 0.20% to 10% by weight, based on the monomers used overall in the polymerization. The amount of crosslinking agents is particularly preferably 0.2 to 0.5% by weight, based on the total monomers used.

According to a particularly preferred embodiment, the water-soluble monomers are polymerized in the presence of at least 1000 ppm of at least one crosslinking agent and at least 1% by weight of at least one regulator, the amounts based in each case on the monomers used. Suitable crosslinkers and regulators are described above. Polymerization regulators used with particular preference are isopropanol, formic acid and their alkali metal and ammonium salts, thioglycolic acid and their alkali metal and ammonium salts, and all regulators which have a similarly high transmission constant to thioglycolic acid. The polymerization regulators are preferably used in amounts of 0.25 to 10% by weight, based on the monomers used in the polymerization. Mixtures of the polymerization regulators can also be used in the polymerization.

To polymerize the monomers, they are first dissolved in water. The concentration of the monomers in the aqueous solution is 20 to 80, preferably 30 to 60% by weight. The aqueous solution is then emulsified to form a water-in-oil emulsion in an inert hydrophobic liquid (oil phase) in the presence of at least one water-in-oil emulsifier. Virtually all of them cannot be used as inert hydrophobic liquids with water miscible liquids are used that do not interfere with the polymerization. Aliphatic and aromatic hydrocarbons or mixtures of aliphatic and aromatic hydrocarbons are preferably used for this. Suitable aliphatic hydrocarbons are, for example, pentane,

Hexane, heptane, octane, nonane, decane, cyclohexane, decalin, methylcyclohexane, isooctane and ethylcyclohexane. Aromatic hydrocarbons which are used as the hydrophobic liquid in reverse suspension polymerization are, for example, benzene, toluene, xylene and isopropylbenzene. In addition, it is also possible to use halogenated hydrocarbons, such as tetrachloroethane, hexachloroethane, trichloroethane and chlorobenzene. Cyclohexane or hydrocarbons with a boiling range from 60 to 170 ° C. are preferably used. The proportion of the oil phase in the structure of the water-in-oil polymer emulsion is 15 to 70, preferably 20 to 60% by weight.

The known water-in-oil emulsifiers are used to disperse the aqueous monomer solution in the oil phase. These are, for example, sorbitan esters, such as sorbitan monostearate, sorbitan monooleate, sorbitan palmitate and sorbitan laurate, and glycerol esters, the acid component of which is derived from C ₁₄ to C ₂ o-carboxylic acids. Further suitable emulsifiers are the water-in-oil emulsifiers known from DE-A-25 57 324, which are obtainable by reacting

A) Cιo-C ₂₂ fatty alcohols with epichlorohydrin in a molar ratio of 1: 0.5 to 1: 1.5 to glycidyl ethers,

B) reaction of the glycidyl ethers with (1) saturated, 2 to 6 OH

Group-containing C ₂ -Cg alcohols or their monoethers with C 1 -C 6 fatty alcohols, in the molar ratio glycidyl ether to (1) or (2) from 1: 0.5 to 1: 6 in the presence of acids or bases and

C) Alkoxylation of the reaction products according to (B) with at least one C ₂ -C ₄ alkylene oxide in a molar ratio of 1: 1 to 1: 6.

Further suitable emulsifiers are made up of at least one hydrophilic and at least one hydrophobic block, the blocks each having molar masses of more than 500 to 100,000, preferably 550 to 50,000 and very particularly preferably 600 to 20,000. The emulsifiers can have a comb-like or linear structure. Linear block copolymers of the AB or ABA type, where A is a hydrophobic and B is a hydrophilic polymer block, are known, cf. EP-A-0 000 424 and EP-A-0 623 630. The emulsifiers to be used are preferred soluble in the used water-immiscible solvent.

The hydrophilic blocks themselves are more than 1%, preferably 5% by weight, soluble in water at 25 ° C. Examples are blocks which are built up from ethylene oxide, propylene oxide or butylene oxide units, optionally in a mixture with one another. The hydroxyl groups of the alkylene oxide blocks can be additionally modified by sulfate or phosphate ester groups. Suitable other blocks are derived from polytetrahydrofuran,

Poly (1, 3-dioxolane), poly (2-methyl-2-oxazoline), polyethyleneimine, polyvinyl alcohol, polyvinylamine, polyvinylpyrrolidone, poly (meth) acrylic acid, polyamidoamines, gelatin, cellulose derivatives or starch. Blocks based on ethylene oxide and / or propylene oxide units are particularly preferred.

The hydrophobic parts of the emulsifiers consist for example of blocks of polystyrene, polyalkyl (meth) acrylates, polysiloxanes, poly (hydroxyalkanoic acids) such as e.g. Polycondensates from 2-hydroxypropanoic acid, 2-hydroxybutanoic acid, 2-hydroxyisobutanoic acid,

2-hydroxyheptanoic acid, 10-hydroxydecanoic acid, 12-hydroxydodecanoic acid, 12-hydroxystearic acid, 16-hydroxyhexadecanoic acid, 2-hydroxystearic acid, 2-hydroxyvaleric acid or the corresponding condensates obtained from lactones, condensates from diols and dicarboxylic acids such as polyethylene adipate, polylactamates such as poly-caprolactams , Polyisobutylene or polyurethane. Blocks of polystyrene, polymethyl methacrylate, polybutyl methacrylate, polyhydroxyalkanoic acids with more than 10 carbon atoms in the alkane unit, polydimethylsiloxanes or polyisobutylenes are preferred. Blocks of polystyrene, polyhydroxy fatty acids such as poly (12-hydroxystearic acid) or polydimethylsiloxanes are very particularly preferred.

Of these compounds, such block copolymers are preferably used as emulsifiers, where

A is a hydrophobic polymer block from the group consisting of polystyrene, poly (hydroxycarboxylic acids), polydimethylsiloxanes or polyisobutylene and

B is a hydrophilic polymer block from the group of the C - to C ₄ -polyalkylene glycols

is. The water-in-oil emulsifiers in question have an HLB value of at most 8. The HLB value is the hydrophilic-lipophilic balance of the emulsifier, cf. WC Griffin, J. Soc. Cosmet. Chem. Volume 1, 311 (1949). The water-in-oil emulsifiers are, based on the monomers used, in one

Amount of 2 to 20, preferably 5 to 15 wt .-% used. Those water-in-oil emulsifiers which are described in the aforementioned DE-A-25 57 324 are preferably used.

Suitable radical initiators are all polymerization initiators commonly used, such as the above-mentioned compounds of component d). Water-soluble initiators are preferred, with either a single initiator or mixtures of several initiators being used. The choice of initiators depends primarily on the temperature at which the polymerization is carried out. Additional salts of heavy metals, e.g. Use copper, cobalt, manganese, iron, nickel and chromium salts and / or organic compounds, such as benzoin, dirnethylaniline, ascorbic acid and reducing agents, such as, for example, alkali disulfite or formaldehyde sodium sulfoxylate, together with at least one of the radical initiating polymerization initiators. Such mixtures of initiators enable polymerization at lower temperatures. The reducing component of so-called redox initiators can be formed, for example, from sodium sulfite, sodium bisulfite, sodium formaldehyde sulfoxylate or hydrazine. Based on the monomers used in the polymerization, 100 to 10,000, preferably 100 to 2000, ppm of a polymerization initiator or a mixture of several polymerization initiators are required. The stated amounts of initiator correspond to approximately 0.002 to 0.3 mol. % Initiator, based on the monomers used.

In a preferred embodiment of the invention, the polymerization of the water-soluble monomers is additionally carried out in the presence of at least one oil-in-water emulsifier. The use of this group of emulsifiers enables the production of particularly fine-particle, sedimentation-stable water-in-oil polymer emulsions. Suitable oil-in-water emulsifiers are, for example, all wetting agents which have an HLB value of at least 10. This group of emulsifiers are essentially hydrophilic water-soluble compounds, such as ethoxylated alkylphenols or ethoxylated fatty alcohols. Products of this type are obtained, for example, by reacting C ₈ to Cχ alkylphenols or C ₈ -C ₂ fatty alcohols with ethylene oxide. Preferably C ₂ -C 8 ethoxylated fatty alcohols. The molar ratio of alkylphenol or fatty alcohol to ethylene oxide is generally carries 1: 5 to 1:20. Other suitable emulsifiers are, for example, alkoxylated fatty amines. If the emulsifiers have an HLB value of 10 or higher in the polymerization, they are used in amounts of 1 to 20, preferably 2 to 15,% by weight, based on the monomers to be polymerized.

The monomers are polymerized in the aqueous phase of a water-in-oil emulsion in the presence of water-in-oil emulsifiers and, if appropriate, protective colloids, which are usually used in reverse suspension polymerization and, if appropriate, oil-in-water. Emulsifiers and in the presence of radical-forming polymerization initiators.

The water-in-oil polymer emulsions are dewatered azeotropically, preferably in the presence of agglomerating polyalkylene glycols.

According to a special process variant described in EP-B-0 412 388, the water-soluble monomers are polymerized in the presence of 0.1 to 10% by weight, based on the monomers used in the polymerization, of protective colloids or become protective colloids added to the water-in-oil polymer suspension after the end of the polymerization at any time before isolating the polymer powder. In the latter case, the amounts of protective colloid are 0.1 to 10% by weight, based on the polymer of the optionally dewatered water-in-oil polymer emulsion. Sorbitan esters can be used both as a water-in-oil emulsifier and as a protective colloid, the water-in-oil emulsifiers belonging to a different class of compound than the protective colloids. If, for example, a sorbitan ester is used as the water-in-oil emulsifier, at least one of the polymeric compounds usually used as the protective colloid in reverse suspension polymerization is used as the protective colloid. For example, the preferred procedure is to use as water-in-oil emulsifier those products which are considered in DE-PS-25 57 324 for the preparation of particularly stable water-in-oil polymer emulsions. In such a case, the protective colloid used is either sorbitan esters or, preferably, polymeric protective colloids which are usually used in reverse suspension polymerization. Protective colloids used with particular preference are sorbitan esters, which have already been mentioned above under the water-in-oil emulsifiers, and graft polymers which, according to EP-A-0 290 753, are used as protective colloids in the reverse suspension polymerization. The preparation of the graft polymers is described in EP-B-0 412 388, to which full reference is made here.

The amount of protective colloid used is 0.1 to 10, preferably 0.2 to 5% by weight, based on the monomers used in the polymerization or on the polymer formed from the monomers.

The water-in-oil polymer emulsions can be dewatered under the conditions described in WO-A-92/13912. After the azeotropic dewatering, there are agglomerations of primary particles which, according to sieve analysis, have an average particle diameter of approximately 20 to 5000, preferably 50 to 2500 μm. The agglomerated polymer particles contain primary particles with an average particle diameter of 0.1 to 15 μm. At least 80, preferably up to 95 to 99% of the water in the water-in-oil polymer emulsions is removed by azeotropic distillation. Small amounts of water that remain in the polymer do not interfere. When agglomerated particles dried in water are introduced by azeotropic distillation, they disintegrate into the primary particles.

If the water-in-oil polymer emulsions obtained are dewatered in the presence of polyalkylene glycols as agglomeration aids, polyalkylene glycols are used which are obtained by addition of alkylene oxides, e.g. Ethylene oxide, propylene oxide, 1,2-butylene oxide, isobutylene oxide and tetrahydrofuran, on alcohols, phenols, amines or carboxylic acids are available. The alkylene oxides and tetrahydrofuran mentioned can be polymerized either alone or as a mixture. If mixtures are used, polymeric compounds are obtained in which the alkylene oxide units are randomly distributed. However, the alkylene oxides can also be allowed to react in the customary manner to form block copolymers. Homopolymers of ethylene oxide are obtained, for example, by adding ethylene oxide to ethylene glycol. To prepare homopolymers of propylene oxide, propylene oxide is added to propylene glycol 1, 2, propylene glycol 1, 3 or to mixtures of the isomers mentioned. The homopolymers of the other alkylene oxides are prepared in a corresponding manner.

Block copolymers suitable as agglomeration aids are produced, for example, by first adding ethylene oxide to ethylene glycol and allowing it to react and then adding propylene oxide under the usual conditions, ie by catalysis with alkali metal hydroxides or calcium oxide. Here there are many ways to vary the order of the blocks of alkylene oxide units. For example, an ethylene oxide block can be followed by a propylene oxide block and then an ethylene oxide block. Likewise, polyalkylene glycols can be used as agglomeration aids which have an ethylene oxide block, a propylene oxide block and a butylene oxide block, or polyalkylene glycols in which a propylene oxide block is followed by an ethylene oxide block or those polyalkylene oxides in which a butylene oxide block Block is followed by a propylene oxide block and, if necessary, an ethylene oxide block.

The end groups of the resulting polyalkylene glycols can be closed on one side or on both sides. Polyalkylene glycols sealed on one side are obtained, for example, by adding alkylene oxides to alcohols, phenols, amines or carboxylic acids. Suitable alcohols are, for example, monohydric C ₁ -C ₂ -alcohols, for example methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, n-octanol, isooctanol and stearyl alcohol. Polyhydric alcohols can also be used as alcohols, for example, as already mentioned above, ethylene glycols or propylene glycols and also glycerol, pentaerythritol and hexanediol-1, 6. The alkylene oxides can also be phenol, and substituted phenols, such as C 1 -C 4 -alkylphenols be added. Amines are also suitable as end group closures, for example C 1 -C ₈ -alkyl- or dialkylamines and diamines, preferably ethylenediamine. Of particular interest here are commercially available products which can be obtained, for example, by sequential addition of ethylene oxide and propylene oxide onto ethylenediamine. Thioalcohols such as mercaptoethanol, mercaptopropanols and mercaptobutanols can also be alkoxylated. The terminal OH groups of the polyalkylene glycols can also be replaced, for example, by amino groups. Polyalkylene glycols whose terminal OH groups are etherified or esterified are also suitable as agglomeration aids.

The polyalkylene glycols in question contain at least 2 alkylene oxide units copolymerized. Suitable agglomeration aids are, for example, polyethylene glycols, polypropylene glycols, block copolymers of ethylene oxide and propylene oxide blocks of the structure EO-PO, PO-EO-PO or EO-PO-EO, polyethylene glycols etherified on one or both sides with C 1 -C ₄ -alcohols and those compounds which are obtainable by addition of first ethylene oxide and then propylene oxide or in reverse order on ethylenediamine. Suitable agglomerating polyalkylene glycols are, for example, diethylene glycol, triethylene glycol, tetraethylene glycol, pentamethylene glycol, hexaethylene glycol, heptaethylene glycol, octaethylene glycol, diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol diethyl ether, diethylene glycol monoethyl ester, triethyl glycol mono- and dimethyl ether, triethylene glycol mono- and diethyl ether, dialkylene glycol dibutyl ether, diethylene glycol monobutyl ether, diethylene glycol 5-ethylene glycol ethylenediphenyl ether-3% glycol mono- ethylene glycol 3-ethylene glycol mono-ethylene glycol-3-ethylene glycol-bis-ethylene glycol-3-ethylene glycol-3% PO-EO-PO block copolymers with average molecular weights of 178 to 2 million and EO-PO-EO block copolymers with average molecular weights of 134 to 2 million,

10 dipropylene glycol diacetate, diethylene glycol diacetate, dipropylene glycol monoacetate, diethylene glycol monoacetate, dipropylene glycol dimethyl ether and dipropylene glycol monomethyl ether. The molecular weights given relate to the number average. The agglomeration aids are preferably used in amounts of 5 to

15 20% by weight, based on the polymer present in the water-in-oil emulsion, is used.

After azeotropic dewatering in the presence of the polyalkylene glycols, agglomerated polymer particles are present which are slightly iso-

20, e.g. by filtering, decanting the

Hydrogen carbon oil or centrifugation. The hydrocarbon oil still adhering to the agglomerated particles can be easily removed from the agglomerated polymer particles, e.g. by drying in a drying cabinet, preferably drying at higher

25 temperatures under reduced pressure.

Suitable inorganic, electroneutral compounds B) (salts or minerals) are generally compounds which are composed of a cation or more cations and an anion or more anions 30, at least one cation type other than protons being involved, and the compounds are electroneutral, i.e. the positive and negative charges of the ions compensate each other.

35 Generally suitable as cations are all metals of the main groups of the periodic table, such as Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, Al, Ga, In, Tl, Ge, Sn, Pb, Sb and Bi as well all sub-group metals of the periodic table, such as Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag,

40 Au, Zn, Cd, and Hg, in all positive oxidation levels and their mixtures.

The cations can preferably be selected from the following main and subgroup metals Mg, Ca, Sr, Ba, Al, Pb, V, Cr, Mo, W, Mn, 45 Fe, Cu, and Ni in all occurring positive oxidation states and their mixtures . Suitable anions are derived from the partially or completely deprotonated acid esters of inorganic acids and the hydroxide and oxide ions and mixtures of several identical or different anions.

In particular, these are:

Carbonate C0 ₃ ^2- and bicarbonate HC0 ₃ ^~ ;

Phosphates PÜ ₄ ^3- , hydrogen phosphates HPO ₄ ² - and dihydrogen phosphates H ₂ P0 ₄ ^~ , condensed phosphates, such as dihydrogen diphosphates H ₂ P ₂ 0 ^2_ , diphosphates P ₂ 0 ₇ ^{4 ~} , polyphosphates P _n θ _{3n + l} ^{(n + 2) _} and metapolyphosphates P _n 0 _3n ^{n ~} ; Silicates, such as, for example, orthosilicates Siθ ₄ ^4- , orthodisilicates Si ₂ θ ^6_ , more condensed silicates, such as metasilicates (Si0 ^2_ ) _n , with a general distinction being made between more condensed silicates with limited anion sizes, such as the island silicates [Si0 ₄ ] ⁴ - , [Si ₂ 0 ₇ ] ⁶ -, [Si ₃ 0 ₉ ] ⁶ -, [Si ₆ 0ι ₈ ] ¹² -, etc., and higher condensed silicates with unlimited anion size, such as chain silicates co [Si0 ₃ ] ^{2 ~} , Band silicates oo [Si ₄ θn] ^6_ , network silicates oo [Si ₂ 0 ₅ ] ² , etc., differentiates; - Oxides and double oxides (mixed oxides), such as those of the oxometals (e.g. Bi ₂ Cu0 ₄ ), spinels (e.g. MgAl ₂ 0, ZnAl ₂ θ ₄ , (Fe, Mg) (Al, Fe) ₂ 0, (Fe, Mg) (AI, Cu, Fe) ₂ 0), inverse spinels and valence-mixed oxides (eg red lead Pb ₃ θ ₄ = 2Pb ^II 0-Pb ^IV 0 ₂ ); - hydroxides;

Sulfides S ^2_ and polysulfides Sn ^2_ ; Sulfites S0 ^2_ and hydrogen sulfites HSO ₃ -;

Sulphates SO ₄ ² ", hydrogen sulphates HS0 ₄ ^~ and disulphates S ₂ O- ₇ ² -; tungstates, such as monotungstates WO ₄ ^2- , di-tungstates W ₂ 0 ^2_ , isopoly-tungstates W ₆ θ ₂ ι ^5" and paratungstates Wι θ ₄ i ^10- ; Halides, especially F ^~ and Cl ^" ; or their mixtures.

In a preferred embodiment, the composite materials according to the invention contain at least one salt or mineral A) which is sparingly soluble in water. These include, for example, magnesium chloride, magnesium dihydrogen diphosphate, magnesium diphosphate, magnesium polyphosphate, calcium carbonate, calcium phosphate, apatite Ca ₅ [(F, C1.0H, 1 / 2C0 ₃ ) (P0 ₄ ) ₃ , especially fluorapatite Ca ₅ F (P0 ₄ ) ₃ and Hydroxyapatite Cas (OH) (P0 ₄ ) ₃ , calcium silicate, strontium carbonate, strontium sulfate, barium carbonate, barium sulfate, aluminum carbonate, basic aluminum carbonate, aluminum hydroxide, aluminum phosphate, basic aluminum phosphate, spinels, inverse spinels, iron oxides, cobalt oxides, vanadium sulfide, molybdenum sulfide, etc. The composite materials according to the invention contain the inorganic salts and / or minerals B) in an amount of 50 to 99.9% by weight, preferably 60 to 99% by weight, based on the total weight.

In general, the composite materials according to the invention are prepared by crystallizing the aforementioned salts or minerals B) in the presence of the water-swellable polymer gels A). Dried swellable polymers as well as already swollen polymer gels A) can be used for the production. Dried polymers can be pre-swollen with an aqueous solution of one or more of the above-described salts and / or minerals in water or a water-containing solvent, as well as directly dry with such a solution, e.g. with stirring using a suitable stirrer.

If dried polymers A) are pre-swollen to produce the composite materials according to the invention, they can be isolated before being combined with a salt or mineral solution, e.g. by filtering over a frit, or together with the solvent used for swelling with the salt or mineral solution, e.g. with stirring. In this case both the pre-swollen polymer gel can be added to the salt or mineral solution, e.g. by pouring or dropping at a certain rate, as well as vice versa.

Polymer gels A) already present in the swollen state can, if desired, be diluted with water or a water-containing solvent before the combination. Then proceed as described above for the pre-swollen, dry polymers.

The resulting mixture of polymer gel A) and salt or mineral solution B) is optionally left for a certain period of time, preferably about 1 to about 20 hours, at intervals or permanently by stirring or shaking with a suitable device for thorough mixing is ensured. The modified polymer gel is then filtered off and optionally washed with water or a water-containing solvent.

Thereafter, the above-described process for combining swollen polymer gels and salt and / or mineral solutions can be repeated a number of times, preferably 1 to 3 times.

For isolation, the polymer gel with the incorporated salt and / or mineral is filtered off, optionally washed once or several times with water or a water-containing solvent and dried. Known methods such as drying can be used for drying

Drying in a drying cabinet, under vacuum, with infrared radiation, etc., can be used.

In general, the composite materials according to the invention are obtained in the form of a granular material with particle sizes between 0.01 and 20 mm, preferably 0.1 to 10 mm.

According to a preferred embodiment of the process according to the invention, solutions of readily soluble salts of the cations to be incorporated and solutions of easily soluble salts of the anions to be incorporated in water or a water-containing solvent are used to produce the composite materials, which, after their combination, form poorly soluble salts B), which then form in the presence crystallize the polymer gels A).

In particular, aqueous solutions of the cations Mg ²⁺ , Ca ⁺ , Sr ²⁺ , Ba ²⁺ , Al ³⁺ , Pb ⁺ , Pw ⁴⁺ , V ³⁺ , Mo ²⁺ , Fe ⁺ , Fe ³⁺ , Co ²⁺ , and Co ³⁺ in the form of their readily soluble chlorides, sulfates, hydroxides, oxides, acetates, etc., with aqueous solutions of anionic carbonates, silicates, phosphates, tungstates, hydroxides, sulfides, polysulfides, sulfites and sulfates, in the form of their easily soluble alkali metal salts, combined in the presence of a polymer gel A), with sparingly soluble salts, such as, for example, magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, magnesium pyrosulfate, strontium sulfate, barium sulfate, calcium phosphate, aluminum phosphate, basic aluminum phosphate, iron oxide, cobalt oxide, hydroxyapatite, hydroxyapate , Vanadium sulfide, molybdenum sulfide, calcium silicate, magnesium polyphospha, aluminum carbonate, basic aluminum carbonate, aluminum hydroxide, etc. form. If a solid polymer is used to produce the composite materials with sparingly soluble salts, this can be pre-swollen in water or a water-containing solvent or added directly to the solution of one of the abovementioned readily soluble salts of the cation or anion component. If the dry polymer is allowed to swell in water or a water-containing solvent, the resulting polymer gel can first be isolated or combined with one of the two components together with the solvent. Likewise, an already pre-swollen gel is advantageously first combined with one of the two components. The mixture of polymer gel and one component can then be added to the other dissolved component or vice versa. As previously described for the general manufacturing process, the above process of crystallizing the sparingly soluble salt in the presence of the polymer gel can be repeated several times, preferably 1 to 4 times.

The resulting composite material is isolated and dried as described for the general process.

According to a special embodiment of the method according to the invention, carriers coated with composite materials are produced. As mentioned above, a polymer gel A) is first applied to a carrier material.

The polymer absorbers A) used are preferably the superabsorbers described above, in particular in the form of foams, which do not lose their geometric shape during swelling.

Suitable carriers are e.g. Wood, paper, metals, plastics, e.g. Films made of polyethylene, polypropylene, polyamide, etc., glass, ceramic supports, fabrics made of natural or synthetic fibers in the form of fleeces, fluffs, tissues etc. or other foams. The aforementioned foam-shaped superabsorbers can advantageously be applied to the carrier material in certain structures or in different layer thicknesses. The polymer gels can have any regular or irregular shapes. The polymer gel is polymerized on the surface of the carrier material by one of the methods described above. The material coated with polymer gel can then be provided with a coating of composite material by crystallizing minerals using one of the methods described above.

Another object of the invention is the use of free or supported composite materials as a support material for catalysts, such as catalysts for hydrogenation and as a tablet binder, fertilizer, building material, slow-release matrix material for active pharmaceutical ingredients or crop protection agents, fillers for plastics, such as polyvinyl chloride (PVC) , Polyethylene terephthalate (PET) etc., pigments for paints, fillers for paper, abrasives, abrasives, information stores, lubricants, and cosmetics. According to a preferred embodiment, magnetizable minerals are used to produce the composite materials, so that magnetic moldings are formed. The invention is illustrated by the following non-limiting examples.

Examples

A) Preparation of the polymer gels

example 1

Production of a super absorber

In a kettle denoted by 1, 1362.5 g of distilled water, 8363.5 g (32.92 mol) of a 37% aqueous sodium acrylate solution, 789.85 g (11.0 mol) of acrylic acid, 19.43 g of trimethylolpropane triacrylate and 64.75 g of a 15% aqueous sodium peroxodisulfate solution. This solution was heated to 20 ° C. Nitrogen was passed through the solution for 20 minutes and at the same time a solution of 0.097 g of ascorbic acid in 499.9 g of distilled water was prepared in a second kettle, the temperature was also raised to 20 ° C. and nitrogen was passed through the solution for 20 minutes. After completion of the solutions, the contents of the two kettles were pressed synchronously into a tubular reactor of 1 m in length under a pressure of 2 bar in a nitrogen countercurrent, both solutions using a static mixer before entering the reactor at the point denoted by 3 in the figure were mixed.

After mixing the two aqueous solutions described above, the polymerization started immediately. The nitrogen purge of the reactor was switched off and the tubular reactor was closed. The reaction mixture reached a maximum temperature of 99 ° C. It was allowed to cool to room temperature overnight. Then nitrogen pressure of 9 bar was applied at the top of the reactor. After opening, the entire gel-like reactor contents could be discharged without residue. The solid, viscous, barely sticky gel thus obtained was further comminuted with a cutting knife and then dried at 70 ° C. in a drying cabinet at 20 mbar for 15 hours. The absorption capacity of water was 45 g / g polymer.

Example 2

Production of a super absorber

Example 1 was repeated with the only exception that the polymerization was carried out under a pressure of 8 bar. The maximum temperature of the reaction mixture reached was at 95 ° C. The consistency of the gel obtained was firm, viscous and hardly sticky.

Example 3 Preparation of a Super Absorber

Based on the following approach:

Boiler 1:

distilled water: 807.7 g sodium acrylate solution 37% in water: 8843.4 g (35.8 mol) acrylic acid: 857.5 g (11.9 mol)

Trimethylolpropane triacrylate: 21.1 sodium peroxodisulfate solution 15% in water: 70.3 g

Boiler 2

distilled water: 499.9 g ascorbic acid: 0.105 g

the mixture was polymerized as described in Example 2. The maximum temperature reached was 112 ° C. The consistency of the gel obtained was firm, viscous and only a little sticky. The polymer had the following properties:

Absorption capacity: 44 g / g

Example 4 Production of a Super Absorber

Based on the following approach:

Boiler 1:

distilled water: 118.5 g sodium acrylate solution 37% in water: 9482.1 g (37.6 mol) acrylic acid: 903.2 g (12.5 mol)

Trimethylolpropane triacrylate: 22.2 sodium peroxodisulfate solution 15% in water: 74.0 g

Boiler 2

distilled water: 499.9 g ascorbic acid: 0.111 g the mixture was polymerized as described in Example 2. The maximum temperature reached was 127 ° C. The consistency of the gel obtained was firm, viscoplastic and only slightly sticky. The polymer had the following properties:

Absorption capacity: 40 g / g

Example 5

Production of a super absorber

Based on the following approach:

Boiler 1:

distilled water: 1362.5 g

Sodium acrylate solution 37% in water: 8363.5 g (32.9 mol) acrylic acid: 789.9 g (11.0 mol) trimethylolpropane triacrylate: 19.4

Boiler 2

distilled water: 497.66 g

2,2'-azobis [2- (2 '-imidazolin-2-yl) propane] dihydrochloride: 2.34 g

the mixture was polymerized as described in Example 1. The maximum temperature reached was 97 ° C. The consistency of the gel obtained was firm, viscoplastic and only slightly sticky.

Absorption capacity: 44 g / g

Example 6

Production of a foam-shaped super absorber

The following components are mixed in a beaker using a magnetic stirrer:

224.20 g of a 37.3% sodium acrylate solution in water 21.36 g of acrylic acid

1.05 g of triacrylic acid ester of a glycerol 3 etherified with 20 ethylene oxide, 15 g of addition product of 80 mol of ethylene oxide with 1 mol of tallow fatty alcohol 0.53 g of 1,4-butanediol diacrylate 4.30 g pentane 49, 68 g water

The homogeneous mixture obtained is poured into a 2 liter flask into which argon is introduced from below. Two whisks are inserted into the flask, each of which is connected to a Janke & Kunkel type RW 20 DZM stirrer. The argon flow is adjusted so that it bubbles through the reaction mixture at a rate of 2.5 l / h. The two stirrers are first set to a speed of 60 rpm. 45.00 g of finely ground superabsorbent (particle size <100 μm) are added to the reaction mixture and mixed in homogeneously. The free opening of the piston is almost completely sealed with parafilm and the stirrer speed is increased to 1000 rpm. The mixture is whipped at this speed for 20 min at room temperature. 5 minutes before the end of the whipping process, 11.9 g of a 3% solution of 2, 2 '-azobis (2-amidinopropane dihydrochloride) are added to the flask. After the whipping period, a finely divided, free-flowing whipping foam is obtained.

The foam is filled in a layer thickness of 3 mm into a box made of polypropylene (dimensions: width 20 cm, depth 20 cm, height 15 cm), which was previously flushed with argon. In this box, the foam is irradiated with an imagesetter for 60 seconds. The result is an evenly 3 mm thick, slightly flexible foam layer that can be easily removed from the box. It is dried in a vacuum drying cabinet at 70 ° C and a vacuum of 20 mbar to a residual water content of 25%. For equilibration, the dried foam layer is stored overnight in a tightly closed polyethylene bag. After that, the foam layer obtained is still soft and flexible. For test purposes, a small part of the sample is dried completely in vacuo.

Properties of the super absorber foam:

Density: 650 g / 1

Extractable proportions: 5.7%

Absorption: 23.5 g / g retention: 10.6 g / g

AS: 1.1 g / g-sec Uniformity of absorption: grade 1

Stability in the swollen state: grade 1 Example 7

Production of a foam-shaped super absorber

Input materials: 400.00 g Na-acrylate solution (37.3%) 38.10 g acrylic acid

2.00 g trimethylpropane triacrylate (TMPTA) 21.22 g 2,2'-azobis (N, N'-dimethyleneisobutyramidine) dihydrochloride (3% aqueous solution) 10.00 g Na salt of a Cι ₃ / Cι ₅ -Oxoalcohol- sulfuric acid half-ester

The crosslinker (TMPTA) is first dissolved in the acrylic acid in a screw cap vessel. The Na acrylate and the emulsifier are added with stirring. The mixture is stirred using a magnetic stirrer for at least 4 hours. In a commercially available Bosch kitchen machine with a cover, the mixture is turned into a foam at the highest stirring level. During this process, the air space above the foam is constantly filled with carbon dioxide. After 15 minutes, the starter solution is added and the mixture is beaten for a further 5 minutes. The result is a fine, free-flowing foam with a volume of approx. 3 liters.

The foam is poured into a 15.5x19.0x18.0 cm mold made of polypropylene and polymerized in the microwave for 10 minutes.

A 7 cm thick foam block is obtained.

Properties of the super absorber foam:

Density: 115.3 g / 1

Extractable proportions: 10.4% Absorption: 57.4 g / g retention: 32.9 g / g

AS:> 37 g / g-sec

Example 8

Production of a foam-shaped super absorber

Input materials: 400.00 g Na-acrylate solution (37.3%)

38.10 g acrylic acid

2.00 g of trimethylpropane triacrylate (TMPTA) 21.22 g of 2,2'-azobis (N, N '-dimethylene-isobutyr-amidine) dihydrochloride in the form of a

3% aqueous solution) 10.00 g Na salt of a Cι ₃ / Cι ₅ -Oxoalkoholschwe- rock acid semi-ester 10.00 g of a hydrophilic precipitated silica with an average particle size of 7 μm

The crosslinker (TMPTA) is first dissolved in the acrylic acid in a screw cap vessel. The Na acrylate, the emulsifier and the precipitated silica are added with stirring. The mixture is stirred using a magnetic stirrer for at least 4 hours. In a commercially available Bosch kitchen machine with a cover, the mixture is turned into a foam at the highest stirring level. During this process, the air space above the foam is constantly filled with carbon dioxide. After 15 minutes, the starter solution is added and the mixture is beaten for a further 5 minutes. A fine, rigid whipped foam with a volume of approx. 3 liters is created.

The foam is transferred to a 15.5 * 19.0 * 18.0 cm polypropylene mold and polymerized in the microwave for 10 minutes. An 8 cm thick foam block is obtained.

Properties of the super absorber foam:

Density: 87.5 g / 1

Extractable proportions: 7.4% absorption: 52.3 g / g

Retention: 23.3 g / g

AS: 0, 12 g / g-sec

Example 9 Production of a foam-shaped superabsorbent

Input materials: 400.00 g Na-acrylate solution (37.3%)

38.10 g of acrylic acid 2.00 g of trimethylpropane triacrylate 21.22 g of 2,2'-azobis (N, N '-dimethyleneisobutyr-amidine) dihydrochloride in the form of a 3% strength aqueous solution) 10.00 g of Na salt of a Cι ₃ / Ci5-Oxoalcoholsulfuric acid semi-ester 5.00 g of a hydrophilic precipitated silica with an average particle size of 7 μm

The crosslinker (TMPTA) is first dissolved in the acrylic acid in a screw cap vessel. The Na acrylate, the emulsifier and the precipitated silica are added with stirring. The approach is in a commercially available Bosch kitchen machine with cover whipped to a foam at the highest stirring level. During this process, the air space above the foam is constantly filled with carbon dioxide. After 15 minutes, the starter solution is added and the mixture is beaten for a further 5 minutes. A fine, rigid whipped foam with a volume of approx. 2 liters is created.

The foam is transferred to a 15.5x19.0x18.0 cm polypropylene mold and polymerized in the microwave for 10 minutes. A 7 cm thick foam block is obtained.

Properties of the foam:

Density: 99.1 g / 1

Extractable proportions: 9.7% Absorption: 61.3 g / g

Retention: 31.1 g / g

AS: 0.80 g / g-sec

Example 10 Production of a foam-shaped superabsorbent

Input materials: 400.00 g Na acrylate (37%)

38.10 g of acrylic acid 2.00 g of trimethylpropane triacrylate 0.64 g of 2,2'-azobis (N, N '-dimethyleneisobutyr-amidine) dihydrochloride in the form of a 3% strength aqueous solution) 10.00 g of stearic acid triethanolamine ester quaternized with dimethyl sulfate 2 , 50 g of hydroxyethyl cellulose (2%

Brookfield viscosity = 6000 mPas)

The crosslinker is first dissolved in acrylic acid in a screw cap vessel. The Na acrylate, the emulsifier and the hydroxyethyl cellulose are added with stirring. The mixture is then stirred overnight. The mixture is whipped into a foam for 20 minutes in a commercially available Bosch kitchen machine with a lid. During this process, the air space above the foam is constantly filled with carbon dioxide. The starter solution is then added and the polymerizable mixture is beaten for a further 5 minutes. The result is a fine, rigid foam with a volume of approx. 2.5 1. The foam is filled into a 15.5x19.0x18.0 cm mold made of polypropylene and polymerized in the microwave oven.

A 9 cm thick foam block is obtained. Properties of the super absorber foam

Density: 76.4 g / 1

Extractable proportions: 10.3% 5 Water absorption: 55.3 g / g retention: 42.1 g / g

AS: 1.2 g / g-sec

Example 11 10 Production of a foam-shaped superabsorbent

Input materials: 400.00 g 37% aqueous Na-acrylate solution

38.10 g acrylic acid 1.87 g triacrylic acid ester of a glycerol etherified with 20 mol 15 ethylene oxide

0.64 g of 2,2'-azobis (N, N '-dimethyleneisobutyr-amidine) dihydrochloride in the form of a 3% strength aqueous solution) 10.00 g of stearic acid triethanolamine ester quaternized with 20 dimethyl sulfate

A foam is produced according to the instructions given in Example 4. The result is a fine, fairly stiff foam with a volume of approx. 3.5 l. The foam is transferred to a 25 15.5x19.0x18.0 cm mold made of polypropylene and polymerized for 10 minutes in a microwave oven. An 8 cm thick foam block is obtained.

Properties of super absorber foam 30

Density: 84.3 g / 1

Extractable proportions: 9.8%

Water absorption: 58.4 g / g

Retention: 43.2 g / g

35 AS: 1.1 g / g-sec

Example 12

Production of a foam-shaped super absorber

40 feedstocks: 400.00 g 37% aqueous Na acrylate solution

31.8 g acrylic acid 2.0 g trimethylpropane triacrylate 0.64 g 2,2 'azobis (N, N' dimethylene isobutyramidine) dihydrochloride in the form of a 45 3% aqueous solution)

8.00 g Na salt of a Cι ₃ / Ci ₅ -oxoalcohol sweat- rock acid half ester

2.00 g of cis-alkyl sulfonic acid as Na salt

The starting materials specified above are foamed and polymerized according to the instructions given in Example 4. First of all, a fine, rigid foam with a volume of 3 l is formed. After polymerizing, a 6 cm thick foam block is obtained.

Properties of the super absorber foam

Density: 113.0 g / 1

Extractable proportions: 9.5%

Water absorption: 54.7 g / g

Retention: 43.2 g / g ai: 1.3 g / g-sec

Examples 1 to 62 of EP-B-0 412 388 are examples of the production of highly swellable polymer gels by polymerizing water-soluble monomers in the presence of water-in-oil emulsifiers and protective colloids.

Examples 13 to 16

Production of highly swellable polymers for polymer gels by water-in-oil emulsion polymerization

Preparation of the water-in-oil polymer emulsions

As described in DE-C-36 41 700, the monomer emulsions described below are initially introduced in a 2 l capacity polymerization vessel which is provided with anchor stirrer, thermometer, nitrogen inlet and nitrogen outlet. The polymerizable mixture is then emulsified by adding half the amount of starter for 30 minutes at room temperature under a nitrogen atmosphere at a stirring speed of 200 rpm. The reaction mixture is then heated to a temperature in the range from 55 to 70 ° C. and polymerized in this temperature range for 1.5 h. Then the remaining amount of the starter is added and the reaction mixture is heated for a further 2 hours at 65 ° C. with stirring.

To prepare the monomer emulsions, acrylic acid is initially introduced and neutralized to a pH of 7 by adding aqueous sodium hydroxide solution. Then you add the other components and enough aqueous sodium hydroxide solution that the pH is 8. So much water is then added that the total amount of the reaction mixture is 1000 g. Composition of the monomer emulsions in the preparation of the W /

0-polymer emulsions

Example 13

308 g cyclohexane

17.6 g of a water-in-oil emulsifier, which can be obtained by reacting

A) oleyl alcohol with epichlorohydrin in a molar ratio of 1: 1 to oleyl glycidyl ether,

B) reaction of the oleyl glycidyl ether with glycerol in a molar ratio of 1: 1 in the presence of BF -phosphoric acid at a temperature of 80 ° C. and removal of the catalyst using a basic ion exchanger and C) ethoxylation of the reaction product according to (B) with

2 moles of ethylene oxide,

2.6 g of a surfactant obtained by reacting a Cχ ₃ / Ci ₅ oxo alcohol with 6 mol of ethylene oxide and 4 mol of propylene oxide,

153.8 g of acrylic acid

13.2 g of acrylamide

13.2 g of N-vinyl pyrrolidone

3.6 g thioglycolic acid 0.08 g pentasodium salt of diethylenetriaminepentaacetic acid 0.36 g methylenebisacrylamide

Starter:

0.092 g of 2,2 'azobis (2-amidinopropane) dihydrochloride

Example 14

The composition differs from the composition of the monomer emulsion, which is given for polymer 1 only in that no N-vinylpyrrolidone is used now.

Example 15

The procedure is as in the preparation of polymer 1, but the monomers are acrylic acid and N-vinylpyrrolidone, and the neutralization is carried out using potassium hydroxide solution.

Example 16

The procedure is as indicated for polymer 1, but the is replaced amount used there of 3.6 g of thioglycolic acid (20,000 ppm) by 5.4 g of formic acid (= 25,000 ppm).

B) Production of the composite materials

Example 17

10 g of a polymer according to Example 13 are dissolved in 400 ml of water. The solution is combined with a solution of 212 g of sodium carbonate in 1 liter of water and the combined solutions are slowly poured into a solution of 222 g of calcium chloride in 1 liter of water. The white precipitate is filtered off, washed with water and dried. The yield is 217 g.

Example 18

10 g of crosslinked polyacrylic acid (superabsorber, SAP) according to Example 1 is swollen in 200 ml of 10% sodium carbonate solution for 1 hour with occasional swirling and filtered through a frit and not washed. The swollen SAP is introduced into 200 ml of 10% calcium chloride solution and left there for 1 hour with occasional stirring, and after this time has elapsed, it is filtered off and washed with water. Then the polymer gel is treated again in 10% sodium carbonate solution and the above procedure is repeated 3 more times. After the fourth test run, the gel is washed with water and dried in a drying cabinet at 80 ° C. 46 g of a white, granular material with a particle size of 1-5 mm are obtained.

Example 19

The preparation was carried out analogously to Example 2, with the difference that 20% solutions were used. After performing it three times, 79 g of a granular material with particle sizes between 1-5 mm are obtained.

Example 20

10 g of superabsorbent polymer according to Example 1 are stored in a solution consisting of 350 g of 12.5% sodium hydroxide solution for 20 hours with occasional swiveling. A slimy, swollen mass develops. This mass is introduced into a solution consisting of 148 g of potassium aluminum sulfate in 500 ml of water and left there for 3 hours with stirring. The insoluble fraction is filtered off and washed with water and dried. The result is 106 g of a granular material. Example 21

10 g of superabsorbent polymer according to Example 2 are swollen in 300 ml of a 10% sodium carbonate solution for 20 hours. The mixture is then suctioned off and the polymer gel is stored for 1 hour in 10% potassium aluminum sulfate solution. It is suctioned off and the process is repeated 3 times. After washing and drying, 32 g of a granular material are obtained.

Example 22

10 g of superabsorbent polymer according to Example 3 are swollen in 300 ml of a 10% disodium hydrogenphosphate solution for 20 hours. The polymer gel is suctioned off and, without further washing, introduced into 300 ml of a 10% potassium aluminum sulfate solution and left there for 20 hours and suctioned off. The procedure is repeated 3 times. 18 g of a granular material are obtained.

Example 23

10 g of superabsorbent polymer according to Example 4 are swollen in 300 ml of a 10% disodium hydrogenphosphate solution for 20 hours. The polymer gel is suctioned off and, without further washing, introduced into 300 ml of a 10% calcium chloride solution and left there for 1 hour and suctioned off. The procedure is repeated 3 times. 55 g of a granular material with a particle size between 1 and 5 mm are obtained.

Example 24

10 g of superabsorbent foam according to Example 9 are swollen in 10% sodium carbonate solution and then in 10% calcium chloride solution as indicated in Example 18. The procedure is repeated 3 more times. After soaking for 10 hours, the material is air dried. 33 g of a material with a high proportion of voids are obtained.

Claims

claims

1. composite materials comprising A) at least one water-swellable polymer gel,

B) at least one inorganic, electroneutral compound which comprises one or more cations (s) and one or more anion (s), and optionally further constituents.

2. Composite materials according to claim 1, which contain the polymer gel or the polymer gels A) in an amount of 0.1 to 50 wt .-%, preferably 1 to 40 wt .-%, based on the total weight.

3. Composite materials according to one of claims 1 or 2, which contain the compound or compounds B) in an amount of 50 to 99.9 wt .-%, preferably 60 to 99 wt .-%, based on the total weight.

4. Composite materials according to one of claims 1 to 3, wherein the polymer gel is selected from starch and cellulose derivatives and protein derivatives.

5. Composite materials according to one of claims 1 to 3, wherein the polymer gel contains at least one ethylenically unsaturated monomer copolymerized with a hydrophilic group.

6. Composite materials according to claim 5, wherein the hydrophilic group is a carboxyl, amino and / or hydroxyl group, the carboxyl group being at least partially neutralized and the amino group at least partially protonated or quaternized.

7. Composite materials according to claim 5 or 6, wherein the monomer units with a hydrophilic group make up more than 60% by weight, in particular more than 70% by weight, of the polymer gel.

8. Composite materials according to one of claims 5 to 7, wherein the carboxylic acid group-containing monomer is selected from

Acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid.

9. Composite materials according to one of claims 5 to 8, wherein the polymer gel additionally contains at least one polymerized polymer, which is selected from vinylaromatic compounds, esters of acrylic acid or methacrylic acid with 5 -C ₈ -C ₈ -alkanols, vinyl esters of C ₂ -Cι _8- carboxylic acids, (meth) - acrylonitrile, (meth) acrylamide, N-Cι-C ₆ alkyl and N, N-Di-Cι-C ₆ - alkyl (meth) acrylamides, hydroxy-Cι-C ₆ alkyl (meth) acrylates and N-vinyl lactams.

10. 10. Composite materials according to one of claims 4 to 9, which contain a superabsorbent as polymer gel A).

11. Composite materials according to one of claims 5 to 7, wherein the polymer gel A) foam-like, in particular with core-shell

15 Structure, is present.

12. Composite materials according to one of claims 1 to 3, which contain a polymer gel A) which, when swollen in water or a water-containing solvent, into a colloidal additive.

20 stood passes.

13. Composite materials according to one of the preceding claims, wherein the electroneutral compound comprises at least one cation which is selected from cations of groups IIA,

25 IIIA, IVA, VB, VIB, VIIB and VIIIB of the periodic table.

14. Composite materials according to one of the preceding claims, wherein the cation is selected from Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , Al ³⁺ , Pb ²⁺ , V ³⁺ , Cr ³⁺ , Cr ⁶⁺ , Mo ²⁺ , Mo ⁶⁺ , W ⁶⁺ , Mn ²⁺ , Mn ⁷⁺ , Fe ²⁺ ,

30 Fe ³⁺ , Co ²⁺ , Co ³⁺ and Ni ²⁺ .

15. Composite materials according to one of the preceding claims, wherein the electroneutral compound is selected from carbonates, bicarbonates, phosphates, hydrogen phospha-

35 th, dihydrogen phosphates, condensed phosphates, silicates, oxides and double oxides, hydroxides, sulfides, polysulfides, sulfites, sulfates, hydrogen sulfates, disulfates, tungstates and halides.

16. Composite materials according to one of the preceding claims, wherein the electroneutral compound is selected from magnesium carbonate, magnesium dihydrogen diphosphate, magnesium diphosphate, magnesium polyphosphates, calcium carbonate, calcium phosphate, apatites, calcium silicates, strontium carbonate,

45 strontium sulfate, barium carbonate, barium sulfate, aluminum carbonate, basic aluminum carbonate, aluminum hydroxide, aluminum phosphate, basic aluminum phosphate, spinels, inverse spinels, iron oxides, cobalt oxides, vanadium sulfide and

Molybdenum sulfide.

17. Use of the composite materials according to one of claims 1 to 14 as a carrier material for catalysts, as a tablet binder, fertilizer, building material, slow-release matrix materials for pharmaceutical active ingredients or crop protection agents, magnetic moldings, fillers for polyvinyl chloride, fillers for polyethylene terephthalate, pigments for paints , Fillers for paper, abrasives, abrasives, information stores, lubricants or cosmetics.

18. Moldings comprising a composite material according to one of claims 1 to 16.