MXPA01010496A - Polymer mixture forming hidro - Google Patents

Abstract

A hydrogel-forming polymer mixture, which includes a) a hydrogel I-forming polymer containing radical acids and b) a hydrogel-forming polymer II that contains amino and / or imino radicals wherein the ratio of such radicals to the sum total of such amino / imino radicals are within the range of 1: 9 to 9: 1, useful in hygienic articles absorbent

Description

POLYMER MIXTURE FORMING HIDROGEL The present invention relates to hydrogel-forming polymer blends, which include a) a polymer I that forms hydrogel containing acid radicals and b) a polymer II that forms hydrogel containing amino and / or imino radicals, wherein the ratio of such acid radicals to the sum total of such amino / imino radicals are within the range of 1: 9 to 9: 1, and to the use of these mixtures in absorbent sanitary articles. The development of new polymers that form hydrogel, often refer to superabsorbents, which have better continuous absorbent properties to be of substantial commercial interest, since it is especially in the field of disposable sanitary articles such as diapers or incontinence pads where They associate good absorbent properties with high comfort of use. In addition, better superabsorbents allow the use of low amounts of wood pulp, which makes it possible to manufacture thinner sanitary articles and therefore is of commercial importance, since it reduces packing and transportation costs.

The superabsorbents often provide satisfactory results with respect to their absorption capacity by deionized water, but perform satisfactorily exchange for body fluids such as urine. This "decay" of the superabsorbents is generally attributed to the salt content of body fluids. To minimize this effect, WO 96/15162, WO 96/15163, WO 96/17681 and WO 98/37149 propose a superabsorbent material comprised of an anionic superabsorbent material and a cationic superabsorbent material, the cationic superabsorbent material having polymer units which are functions of quaternary amine and are attributable to the bisalylbisalkylammonium ions. WO 92/20735, WO 96/15180, DE-A-19640329 and WO 98/24832 disclose mixtures of anionic and cationic superabsorbent materials, the subsequent functions possessing quaternary amine, ie, not being deprotonable. The polydialkyldimethylammonium hydroxide used herein has been prepared by polymerization of the corresponding chloride and subsequently has been first converted to the hydroxide form (by extensive washing with sodium hydroxide solution) before it can be mixed with the anionic superabsorbent material after drying. Furthermore, it is necessary to avoid the blocking effect of the reduced fluid transmission gel in the lower superabsorbent layers, so that US 5,599,335, US 5,669,894 and US 5,562,646 describe a test method that refers to this requirement (Saline Flow Conductivity SFC) and the requirements profiles that result from these. EP-A-0210756 shows an absorbent mixture of a cation exchange material and an anion exchange material wherein the material is in both cases a modified cellulose fiber. It is an object of the present invention to provide a novel hydrogel-forming polymer blend having good absorption properties, good good distribution properties and high mechanical stability. It has been found that this object is achieved by the aforementioned polymer blends. The hydrogel forming polymers I are water insoluble polymers having free acid groups. Preference is given to crosslinked polyacids, especially polycarboxylic acids, which may be partially in the salt form. Preference is given to polymers I having an acid group density (meq / g) > 4, especially > 8, in particular > 12. Preference is given to polymers I which are prepared by crosslinked polymerization or copolymerization of monoethylenically unsaturated monomers that support the acid groups.

Alternatively, the monoethylenically unsaturated monomers bearing acid groups can be (co) polymerized without crosslinking and subsequently crosslinked. Examples of such monomers which support acid groups are C3- to C25 ~ monoethylenically unsaturated carboxylic acids or anhydrides such as acrylic acid, methacrylic acid, ethacrylic acid, a-chloroacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, acotinic acid and fumaric acid. It is also possible to use monoethylenically unsaturated sulfonic or phosphonic acids, for example vinylsulfonic acid, alisulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloyloxypropylsulfonic acid, 2-hydroxy-3 acid. -methacryloyloxypropyl sulphonic acid, vinylsulfonic acid phosphonic acid, allylphosphonic acid, styrenesulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid. The monomers can be used alone or mixed. Preferred monomers are acrylic acid, methacrylic acid, vinylsulfonic acid, acrylamidopropanesulfonic acid or mixtures thereof, for example mixtures of acrylic and methacrylic acid, mixtures of acrylic acid and acrylamidopropanesulfonic acid or mixtures of acrylic acid and vinylsulfonic acid. To optimize the properties, it may be reasonable to use additional monoethylenically unsaturated compounds, which do not support an acid group, but are copolymerizable with the monomers that support the acid groups. Such compounds include, for example, the amides and nitriles of monoethylenically unsaturated carboxylic acids, for example acrylamide, methacrylamide and N-vinylformamide, N-vinylacetamide, N-methyl-N-vinylacetamide, acrylonitrile and methacrylonitrile. Examples of additional suitable compounds are vinyl esters of C- to C-saturated carboxylic acids, such as vinyl formate, vinyl acetate or vinyl propionate, alkyl vinyl ethers having at least 2 carbon atoms in the alkyl group, for example, ethylvinyl ether or butyl vinyl ether, esters of C3- to C2 ~ monoethylenically unsaturated carboxylic acids, for example esters of monohydric alcohols of Ci- a Cis and acrylic acid, methacrylic acid or maleic acid, monoesters of maleic acid, for example, methyl acid maleate , N-vinyl lactams such as N-vinylpyrrolidone or N-vinylcaprolactam, acrylic and methacrylic esters of alkoxylated monohydric saturated alcohols, for example alcohols having from 10 to 25 carbon atoms that have been reacted with 2 to 200 moles of oxide of ethylene and / or propylene oxide per mole of alcohol, and also mono-acrylic esters and monomethacrylic esters of polyethylene glycol or pol ipropylene glycol, the molar masses (MN) of the polyalkylene glycols are up to 2000, for example. In addition suitable monomers are styrene and alkyl-substituted styrenes such as ethylstyrene or tert-butylstyrene. These monomers without acid groups can also be used in mixtures with other monomers, for example mixtures of vinyl acetate and 2-hydroxyethyl acrylate in any proportion. These monomers without acid groups are added to the reaction mixture in amounts within the range of 0 to 80% by weight, preferably less than 50% by weight. Possible crosslinkers include compounds containing at least 2 ethylenically unsaturated double bonds. Examples of compounds of this type are N, N'-methylenebisacrylamide, polyethylene glycol di-acrylate diacrylates of polyethylene glycol each derived from polyethylene glycols having a molecular weight of from 106 to 8500, preferably from 400 to 2000, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate. , ethylene glycol diacrylate, propylene glycol diacrylate, butanediol diacrylate, hexanediol diacrylate, hexanediol dimethacrylate, allyl methacrylate, diacrylates and dimethacrylates of block copolymers of ethylene oxide and propylene oxide, polyhydric alcohols, such as glycerol or pentaerythritol, double or triply esterified with acrylic acid or methacrylic acid, triallylamine, tetraalylethylenediamine, divinylbenzene, diallyl phthalate, polyethylene glycoldivinyl ethers of polyethylene glycols having a molecular weight of 126 to 4000, trimethylolpropanediallyl ether, butandiolivinyl ether, pentaerythritoltriallyl ether and / or divinyl ethyleneurea. Preference is given to using water-soluble crosslinkers, for example, N, N'-methylenebisacrylamide, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates derived from additional products of 2 to 400 moles of ethylene oxide with 1 mole of a diol or polyol, vinyl ethers of additional products from 2 to 400 moles of ethylene oxide with 1 mole of a diol or polyol, ethylene glycol diacrylate, ethylene glycol dimethacrylate or triacrylates and trimethacrylates of additional products of 6 to 20 moles of ethylene oxide with 1 mole of glycerol, pentaerythritol triallyl ether and / or divinylurea. Possible crosslinkers also include compounds containing at least one ethylenically unsaturated polymerizable group and at least one additional functional group. The functional group of these crosslinkers has been able to react with the functional groups, essentially the acid groups, of the monomers. Suitable functional groups include, for example, hydroxyl, amino, epoxy and aziridino groups. Useful are for example hydroxyalkyl esters of the aforementioned monoethylenically unsaturated carboxylic acids, for example, 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxybutyl methacrylate, dialkyldiallylammonium halides, such as chloride of dimethyldiallylammonium, diethyldiallylammonium chloride, allylpiperidinium bromide, N-vinylimidazoles, for example, N-vinylimidazole, l-vinyl-2-methylimidazole and N-vinylimidazolines such as N-vinylimidazoline, l-vinyl-2-methylimidazoline, 1-vinyl -2-ethyl-imidazoline or l-vinyl-2-propylimidazoline, which can be used in the form of free bases, in quaternized form or as salts in the polymerization. It is also possible to use dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates such as dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate. The basic esters are preferably used in quaternized form or as salts. It is also possible to use glycidyl (meth) acrylate, for example. The crosslinkers are present in the reaction mixture for example from 0.001 to 20%, preferably from 0.01 to 14% by weight. The polymerization is initiated in the usual manner by means of an initiator. Any initiator that forms free radicals under the polymerization conditions can be used which is usually used in the production of superabsorbents. Polymerization can also be initiated by bombardment of electrons acting in the polymerizable aqueous mixture. However, the polymerization can also be initiated in the absence of initiators of the aforementioned kind, by the action of high energy radiation in the presence of photoinitiators. Useful polymerization initiators include all compounds which decompose to free radicals under the polymerization conditions, 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 peroxodisulfate or potassium peroxodisulfate. Mixtures of hydrogen peroxide and sodium peroxodisulfate can be used in any proportion. Examples of suitable organic peroxides are acetylacetone peroxide, methyl ethyl ketone peroxide, tert-butyl hydroperoxide, eumeno hydroperoxide, ter-amyl perpivalate, tert-butyl perpivalate, tert-butyl perneohexanoate, tert-butyl perisobutyrate, 2-tert-butyl ethylhexanoate, tert-butyl perisononanoate, tert-butyl permaleate, tert-butyl perbenzoate, di (2-ethylhexyl) peroxydicarbonate, dicyclohexyl peroxydicarbonate, di (4-tert-butylcyclohexyl) peroxydicarbonate, di-irynyl peroxydicarbonate, diacetyl peroxydicarbonate, allyl esters, cumyl peroxydecanoate, per-3,5,5-trimethylhexanoate tert-butyl, acetyl cyclohexylsulfonylperoxide, dilauryl peroxide, dibenzoyl peroxide and ter-amyl perneodecanoate. Particularly suitable polymerization initiators are water soluble azo initiators, for example, 2,2'-diisohydrochloride 2,2-azobis (2-amidinopropane) dihydrochloride-azobis (N, N '-dimethylene) isobutyramidine, 2- ( carbamoylazole) isobutyrenitrile, 2,2'-azobis [2- (2'-imidazolin-2-yl) propane] and 4, '-azobis (4-cyanovaleric acid) dihydrochloride. The aforementioned polymerization initiators are used in customary amounts, for example in amounts of 0.01 to 5%, preferably 0.1 to 2.0% by weight, based on the monomers to be polymerized. Useful initiators also include redox catalysts. In the redox catalysts, the oxidizing component is at least one of the per-specified compounds per se and the reduction component is for example ascorbic acid, glucose, sorbose, ammonium or alkali metal bisulfite, sulfite, thiosulfate, hyposulfite, pyrosulfite or sulfur, or a metal salt, such as iron (II) ions or silver ions or sodium hydroxymethylsulfoxylate. The reduction component in the redox catalyst is preferably ascorbic acid or sodium sulfite. Based on the amount of monomers used in the polymerization, from 3.10-6 to 1% in mol can be used for the reduction component of the redox catalyst system and from 0.001 to 5.0% mol for the oxidation component of the redox catalyst, for example . When the polymerization is initiated using high energy radiation, the initiator used is usually a photoinitiator. Photoinitiators include, for example, separators, extraction H- systems or other azides. Examples of such initiators are benzophenone derivatives such as Michler ketone, phenanthrene derivatives, fluorene derivatives, anthraquinone derivatives, thioxanthone derivatives, coumarin derivatives, benzoin ethers and derivatives thereof, azo compounds such as free radical former formerly mentioned , substituted hexaarylbisimidazoles 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, -zido-l-naphthyl 2 '- (N, N-dimethylamino) ethylsulfone, N- (4-sulfonylazidophenyl) maleimide, N-acetyl-4-sulfonylazidoaniline, 4-sulfonylazidoaniline, 4-azidoaniline, 4-azidophenacylbromide, acid p-azidobenzoic acid, 2,6-bis (p-azidobenzilidene) cyclohexanone and 2,6-bis (p-azidobenzilidene) -4-methylcyclohexanone. Photoinitiators, if used, are used in the usual manner in amounts of 0.01 to 5% by weight of the monomers to be polymerized. Subsequently, the crosslinks involve a reaction between polyacids, formed by polymerization of the aforementioned monoethylenically unsaturated acids and optionally monoethylenically unsaturated comonomers and having a molecular weight of about 5000, preferably about 50,000, and compounds which contain at least two reactive groups acid groups. This reaction can be carried out at room temperature or also at elevated temperatures up to 200 ° C. Suitable functional groups are already mentioned above, ie, hydroxyl, amino, epoxy, isocyanate, ester, amido and aziridino groups. Examples of such crosslinkers are ethylene glycol, diethyl glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerol, polyglycerol, propylene glycol, polypropylene glycol, block copolymers of ethylene oxide and propylene oxide, sorbitan fatty acid esters, ethoxylated sorbitan fatty acid esters, Trimethylolpropane, pentaerythritol, 1, 3-butanediol, 1,4-butanediol, polyvinyl alcohol, sorbitol, polyglycidyl ethers such as ethylene glycol diglycidyl ether, polietilenglicoldiglicidiléter, gliceroldiglicidiléter, glicerolpoliglicidiléter, diglicerolpoliglicidiléter, poliglicerolpoliglicidiléter, sorbitolpoliglicidiléter, pentaeritritolpoligicidiléter, propilenglicoldiglicidiléter and polipropilenglicoldiglicidiléter, polyaziridine compounds such as 2 , 2-bishydroxymethylbutanol tris [3- (1-aziridinyl) propionate], 1,6-hexamethylenediethyleneurea, diphenylmethane-4,4'-N, Nf -diethyleneurea, hydroxy epoxy compounds such as glycidol, halo epoxy compounds such as epichlorohydrin and a -methylepifluorohydrin, polyisocyanates such as 2,4-tolylene diisocyanate and hexamethylene diisocyanate, alkylene carbonates such as 1,3-dioxolan-2-one and 4-methyl-1,3-dioxolan-2-one, also bisoxazolines and oxazolidones, also polyquaternary amines such as cond products the preparation of dimethylamine with epichlorohydrin, homo- and copolymers of diallyldimethylammonium chloride and also homo- and copolymers of dimethylaminoethyl (meth) acrylate which are optionally quaternized with, for example, methyl chloride. Additional crosslinkers suitable for subsequent crosslinking are polyvalent metal ions capable of forming ionic crosslinkers. Examples of such crosslinkers are magnesium, calcium, barium and aluminum ions. These crosslinkers are added, for example, as hydroxides, carbonates or bicarbonates to the aqueous polymerizable solution. Suitable additional crosslinkers are multifunctional bases likewise capable of forming ionic crosslinkers, for example polyamines or their quaternized salts. Examples of polyamines are ethylenediamine diethylenetriamine, triethylenetetramine, tetraethylenepentane, pentaethylenehexamine and polyethyleneimines and also polyvinylamines having molar masses of up to 4,000,000 in each case. The crosslinkers are added to the polyacrylic acid or polyacrylic acid salts in amounts of 0.5 to 25% by weight, preferably 1 to 15% by weight, based on the amount of polyacids used. The crosslinked polyacids are preferably used in the polymer mixture of the invention in unneutralized form. However, it may be advantageous to partially neutralize the acid functions. The degree of neutralization will be essentially less than 50%, preferably less than 30%. Useful neutralizing agents include: alkali metal bases or ammonia / amines. Preference is given to the use of sodium hydroxide solution or potassium hydroxide solution. However, the neutralization can also be carried out using sodium carbonate, sodium bicarbonate, potassium carbonate or potassium bicarbonate or other carbonates or bicarbonates or ammonia. In addition primary, secondary and tertiary amines can be used. Useful industrial processes for making these products include all the procedures that are usually used to make superabsorbents, as described for example in Chapter 3 of "Modern Superabsorbent Polymer Technology," F.L. Buchholz and A.T. Graham, Wiley-VCH, 1998. Polymerization in aqueous solution is preferably conducted as a gel polymerization. This involves aqueous solutions of 10-70% strength by weight of the monomers and optionally of a suitable graft base being polymerized in the presence of a free radical initiator using the Trommsdorff-Norrish effect. The polymerization reaction can be carried out from 0 to 150 ° C, preferably from 10 to 100 ° C, not only at atmospheric pressure but also at superatomospheric or reduced pressure. As is usually, the polymerization can also be conducted in a protective gas atmosphere, preferably under nitrogen. By subsequently heating the polymer gels from 50 to 130 ° C, preferably from 70 to 100 ° C, for several hours, the performance characteristics of the polymers can be further improved. Additional useful polymers I include graft copolymers of one or more hydrophilic monomers in a suitable graft base, cross-linked cellulose or starch ethers and esters that support acidic groups, crosslinked carboxymethylcellulose, or natural products having acidic groups and capable of dilation in aqueous fluids, for example alginates and carrageenans. Useful grafting bases may be of natural or synthetic origin. Examples are starch, cellulose or cellulose derivatives and also other polysaccharides and oligosaccharides, polyvinyl alcohol, polyalkylene oxides, especially polyethylene oxides and polypropylene oxides, polyamines, polyamides and also hydrophilic polyesters. Suitable polyalkylene oxides form, for example, formula X wherein R1 and R2 are independently hydrogen, alkyl, alkenyl or aryl, X is hydrogen or methyl, and n is an integer from 1 to 10,000. R 1 and R 2 are each preferably hydrogen, C 1 -C 4 alkyl, C 2 -C 6 alkenyl or phenyl. With respect to polymer II, the term amino is used herein according to the IUPAC rules as implied by the primary amino groups and not amido groups, which are formed when the NH2 radical combines with a carbonyl radical. Correspondingly, the imino is used in the present according to the IUPAC rules as implied by the secondary amino groups (-NH-) and not imido groups, in which the radical NHR has been combined with a carbonyl radical. Useful hydrogel-forming polymers II include the following amino and / or imino-bearing polymers that have been subjected to water-insoluble through cross-linking. Preferred polymers are polymers and copolymers, including graft copolymers, of "vinylamine" or ethyleneimine with or without modification of analogous polymers. a) So-called polyvinylamines, ie polymers containing the group -CH2-CH (NH2) - as a building block characteristic, are obtainable through analogous polymer reactions. Examples of such analogous polymer reactions known to those skilled in the art include the hydrolysis of poly-N-vinylamides such as poly-N-vinylformamide, poly-N-vinylacetamide and poly-N-vinylimides such as poly-N-vinyl succinimide. and poly-N-vinylphthalimide and Hofmann degradation of polyacrylamide under the action of basic hypochlorite. The polyvinylamines are preferably prepared by polymerization of N-vinylformamide and subsequently analogous polymer reaction as described in DE-A-3 128 478. The molar mass of the uncrosslinked polyvinylamine corresponds to a K value (determined by the method of H. Fikentscher in 5% by weight of aqueous NaCl solution at 25 ° C containing 1% by weight of the polymer) of 30-250. The N-vinylformamide units of the polymers can be hydrolyzed to the corresponding polymers comprising vinylamine units by acidic, basic or enzymatic hydrolysis. Fully hydrolyzing for example a homopolymer of N-vinylformamide results in polyvinylamine. Basic hydrolysis is particularly preferred. It provides degrees of hydrolysis of for example 5 to 95%. Particular preference is given to products that have a degree of hydrolysis of 70 to 100 and more preferably to completely hydrolyzed products, ie, maximally 100%, usually 95%. The degree of hydrolysis is determined for example by enzymatic determination of the formate or by polyelectrolyte titration of the available amine functions with potassium polyvinyl sulfate solution. The crosslinked polyvinylamines used as polymers II are desalinated in advance. The media desalted in this context to the salt content in terms of low molecular weight salts (molecular weight <500) is < 8% by weight based on the polymer. The desalting is effected for example by means of dialysis or ultrafiltration processes using a membrane having an exclusion limit of 3000 D. The degree of desalting can be verified using gel permeation chromatography (GPC). The desalting is advantageously carried out after the analogous polymer reaction and before the crosslinking reaction. The solutions II of the desalted polymer are usually crosslinked in aqueous solution. The polymer content of an aqueous solution is generally within the range of 2 to 50% by weight. More concentrated polymer solutions can be cross-linked by adding polar aprotic solvents such as dimethyl sulfoxide or N-methylpyrrolidone. As mentioned above, preference is given to polymers II obtained by crosslinking polyvinylamine having a K value of 30-250, preferably 50-230, especially 70-200. Since the high molecular weight polyvinylamines are slow to crosslink and may not completely crosslink, particular preference is given to crosslinking polyvinylamines having a K value of 70-180 in the non-crosslinked state. The hydrogel-forming polymers II further useful include "vinylamine" copolymers, ie, copolymers formed, for example, of vinylformamide and comonomers and converted into formal vinylamine copolymers by the analogous polymer reactions described above. Useful copolymers include in principle all monomers copolymerizable with vinylformamide. The following monounsaturated monomers can be mentioned by way of example: acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, styrene, ethylene, propylene, N-vinylpyrrolidone, N-vinylcaprolactam, N-vinylimidazole, sulfone-containing monomers or phosphonate groups, vinyl glycol, acrylamido (methacrylamido) alkylenetrialkylammonium salts, diallyldialkylammonium salts, C? -C alkyl vinyl ethers, such as methyl vinyl ether, ethyl vinyl ether, isopropyl vinyl ether, n-propyl vinyl ether, t-butyl vinyl ether, alkyl (meth) acrylamides N- substituted, substituted by the C?-C alkyl group such as N-methylacrylamide, N-isopropylacrylamide and N, N-dimethylacrylamide and also C 1 -C 20 alkyl (meth) acrylates such as methyl acrylate, ethyl methacrylate, acrylate propyl, butyl acrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxy utilo, hydroxybutyl methacrylate, 2-methylbutyl acrylate, 3-methylbutyl acrylate, 3-pentyl acrylate, neopentyl acrylate, 2-methylpentyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, phenyl, heptyl acrylate, benzyl acrylate, tolyl acrylate, octyl acrylate, 2-octyl acrylate, nonyl acrylate and octyl methacrylate. The specific copolymers will be mentioned in detail. For example, DE-A-3 534 273 describes copolymers of N-vinylformamide with vinyl acetate, vinyl propionate, C 1 -C 4 alkyl vinyl ethers, methacrylic and acrylic esters, acrylonitrile and acrylamide and also homologs thereof and vinylpyrrolidone. The concentration of N-vinylformamide can be 10-95% mol, which of the comonomers 5-90% mol. The polymers II further useful include graft polymers formed from alkylene oxide units and N-vinylformamide as described in DE-A-1 951 5943 and cross-linked after hydrolysis. Such graft polymers are prepared by free radical polymerization of N-vinylformamide in the presence of, for example, polyethylene glycols and subsequent basic saponification. Additional advantageous grafting bases are polyvinyl acetate and / or polyvinyl alcohol. According to DE-A-19 526 626, N-vinylformamide can be grafted onto these polymers by free radical polymerization and the resulting polymer subject to hydrolysis with or without desalting and subsequent cross-linking to form polymers II. Useful graft bases for N-vinylformamide also include copolymers of vinyl acetate, acrylic acid, methacrylic acid, acrylamide and acrylonitrile. In addition, according to DE-A-4 127 733, mono-, oligo- and polysaccharides with or without oxidative, enzymatic or hydrolytic degradation are advantageous grafting bases for N-vinylformamide whose weight fraction is from 20 to 95% based on the total amount of the graft base + monomer. These graft polymers are subsequently converted to the free amines by hydrolysis, optionally desalting and finally crosslinking to form polymers II. The graft polymers are preferably formed using N-vinylformamide as the sole monomer. However, it is possible to replace up to 50% by weight of the N-vinylformamide with the aforementioned comonomers of N-vinylformamide. In addition, the polyvinylamines and their copolymers, including graft copolymers, can be modified by additional analogous polymer reactions. These reactions are several and can be found in any organic chemistry textbook, for example "Advanced Organic Chemistry" by Jerry March, 3a. edition, John Wiley &; Sons 1985. Of the many possible reactions involving primary amines, some will now be mentioned by way of illustration. The vicinal amino groups of polyvinylamine are reacted in the presence of formic acid or ortho-iodides to form six-membered cyclic amidines, as described for example in US-A-5 401 808. This may be the case in which some of the Amino groups will react with the vicinal formamide groups to form cyclic amidine structures. Similarly, according to DE-A 4 328 975, the copolymers of acrylonitrile, methacrylonitrile or their homologs and acrylic and methacrylic esters with N-vinylformamide can (during or after the hydrolysis of the formamide groups to the corresponding amino groups) react with adjacent carboxylic ester or nitrile groups in intramolecular condensation reactions to form the corresponding 2-amino-1-imidazoline or the corresponding α-lactam structures. The fraction of the analogously converted polymer amino groups can be up to 50 mol%. As well as these intramolecular polymer reactions of polyvinylamines, there are a large number of possible additional reactions of this type. This includes amidation, alkylation, sulfonamide formation, urea formation, thiourea formation, carbamate formation, acylation with acids, lactones, acid anhydrides and acyl chlorides, thiocarbamation, carboxymethylation, phosphonomethylation and Michael addition, to be named, but a little . The polyvinylamine derivatives prepared in this form are also useful for preparing cross-linked polymers II. The analogous polymer reactions are preferably carried out before for the crosslinking of the polyvinylamines and the copolymers (including graft copolymers) of "vinylamine". The fraction of converted amino groups of polymer analogously is up to 50%, preferably from 10 to 30% mol, of the amino groups in the polymer used. Polymers obtained by subsequent crosslinking are preferred, especially those that are desalinated prior to the crosslinking step. b) It is also possible to use polyethylenimines, grafted ethylenimine polyamidoamines or grafted ethylene imine polyamines and also reaction products of these classes of polymer with α, β-unsaturated carboxylic acids or esters or reaction products with the reaction products of formaldehyde with HCN or formaldehyde with alkali metal cyanides (Strecker reaction) and, if appropriate, subsequent hydrolysis to the corresponding carboxylic acids. An additional class of polymers containing amino groups, preferably ethylene imine units, are known from WO-A-94/12560. Water-soluble partially crosslinked amidated polyethyleneimines which are obtainable by the reaction of polyethylenimines with monobasic carboxylic acids or their esters, anhydrides, acyl chlorides or amides with amide formation and reaction of the amidated polyethylenimines with crosslinkers containing at least two functional groups . The molar masses of useful polyethyleneimines can vary up to 5 million and are preferably in the range of 1000 to 1 million. The polyethyleneimines are partially amidated with monobasic carboxylic acids in this manner, for example, from 0.1 to 90%, preferably from 1 to 50%, of the amidatable nitrogen atoms in the polyethylenimines are presented as the amide group. Useful crosslinkers containing at least two functional groups are mentioned above. Preference is given for using halogen-free crosslinkers. The amino-containing compounds can be reactive with crosslinkers using from 0.1 to 50, preferably from 1 to 5, parts by weight of at least one crosslinker per 1 part by weight of the amino-containing compound. Other useful amino-containing addition products after crosslinking as components in superabsorbents are polyethyleneimines and also quaternized polyethyleneimines. The polyethyleneimines and quaternized polyethyleneimines can, if appropriate, react with a crosslinker containing at least two functional groups. The polyethylene imines can be quaternized, for example, with alkyl halides such as methyl chloride, ethyl chloride, hexyl chloride, benzyl chloride or lauryl chloride and also with, for example, dimethyl sulfate. These reaction products have been desalted, if necessary. In addition, useful amino-containing polymers are polyethyleneimines modified by Strecker synthesis, for example, the reaction products of polyethyleneimines with formaldehyde and sodium cyanide with hydrolysis of the resulting nitriles to the corresponding carboxylic acids. These products can, if appropriate, react with a crosslinker containing at least two functional groups or can crosslink with themselves by amide formation and water removal. Also useful are the alkoxylated polyethylene imines obtainable for example by reacting polyethylenimine with ethylene oxide and / or propylene oxide. The alkoxylated polyethylene imines are reacted with a crosslinker containing at least two functional groups supplied in insoluble water. The alkoxylated polyethylene imines containing 0.1 to 100, preferably 1-3, alkylene oxide units per NH group. The polyethyleneimines can have a molar mass of up to two million. The polyethyleneimines used for alkoxylation preferably have molar masses of 1000 to 50,000. In addition, useful water-soluble amino-containing polymers are reaction products of polyethylene imines with diketenes, for example polyethylene imines having a molar mass of 1000 to 50,000 with distearyldiketene, which are subsequently crosslinked. The crosslinked polyethyleneimines are described, for example, in EP 0895 521. The polyethylene imine was prepared in a conventional manner by cationic polymerization of ethylene imine in the presence of polymerization catalysts such as acids, Lewis acids, acidic metal salts or alkylation reagents. Polyethylene imines having a molecular weight of 1000 to 5,000,000 (determined by static light dispersion, for example), are preferably crosslinked to form polymers II. The crosslinkers for preparing such hydrogel forming polymers II are bi- or polyfunctional, ie they have two or more active groups capable of reacting with the amino or imino radicals of the polymers. As well as also low molecular weight crosslinkers useful crosslinkers further include polymers and copolymers, which are preferably soluble in water.

Useful bi-or polyfunctional crosslinkers include for example (1) di- and polyglycidyl compounds (2) di- and polyhalogen compounds (3) compounds having two or more isocyanate groups, which can be blocked (4) polyaziridines (5) derivatives carbonic acid (6) compounds having two or more activated double bonds capable of undergoing Michael addition (7) di- and polycarboxylic acids and acid derivatives thereof (8) monoethylenically unsaturated carboxylic acids, esters, amides and anhydrides (9) ) di- and polyaldehydes and di- and polyketones. Preferred crosslinkers (1) are, for example, the bischlorohydrin ethers of polyalkylene glycols described in US-A-4 144 123. The diglycidyl ether of phosphoric acid and ethylene glycol diglycidyl ether are also suitable. Additional crosslinkers are the reaction products of at least trihydric alcohols with epichlorohydrin to form reaction products having at least two units of chlorohydrin, polyhydric alcohols used being for example glycerol, ethoxylated or propoxylated glycerols, polyglycerols having 2 to 15. glycerol units in the molecule and also optionally polyglycerols optionally ethoxylated and / or propoxylated. Crosslinkers of this type are known from DE-A-2 916 356 for example. Useful crosslinkers (2) are vicinal a,? - or dichloroalkanes, for example, 1,2-dichloroethane, 1,2-dichloropropane, 1,3-dichlorobutane and 1,6-dichlorohexane. In addition, EP-A-0 025 515 describes α, β-dichloropolyalkylene glycols preferably having 1-100, especially 1-100 ethylene oxide, units for use as crosslinkers. Useful crosslinkers further include crosslinkers (3) containing blocked isocyanate groups, for example trimethylhexamethylene diisocyanate blocked with 2, 2, 6,6-tetramethylpiperidin-4-one. Such crosslinkers are known; see for example DE-A-4 028 285. Preference is furthermore given to crosslinkers (4) which contain aziridine units and are based on polyethers or substituted hydrocarbons, for example 1,6-bis-N-aziridinomethane, see US Pat. A-3 977 923. This class of crosslinkers further include products formed by reacting dicarboxylic esters with ethylene imine and containing at least two aziridino groups, and mixtures thereof. Useful halogen-free crosslinkers of group (4) include reaction products prepared by reacting ethyleneimine with fully esterified dicarboxylic esters with monohydric alcohols of 1 to 5 carbon atoms. Examples of suitable dicarboxylic esters are dimethyl oxalate, diethyl oxalate, dimethyl succinate, diethyl succinate, dimethyl adipate, diethyl adipate and dimethyl glutarate. For example, by reacting diethyl oxalate with ethylene imine gives bis [ß- (l-aziridino) ethyl] oxalamide. The dicarboxylic esters are reacted with ethyleneimine in a molar ratio of 1: at least 4. The reactive groups of these crosslinkers are the terminal aziridine groups. These crosslinkers can be characterized, for example, with the aid of the formula: wherein n is from 0 to 22. Illustrative of crosslinkers (5) are ethylene carbonate, propylene carbonate, urea, thiourea, guanidine, diazomide or 2-oxazolidinone and its derivatives. From this group of monomers, preference is given to using propylene carbonate, urea and guanidine. The crosslinkers (6) are reaction products of polyetherdiamines, alkylene diamines, polyalkylene polyamines, alkylene glycols, polyalkylene glycols or mixtures thereof with monoethylenically unsaturated carboxylic acids, esters, amides or anhydrides of monoethylenically unsaturated carboxylic acids, the reaction products of which contain at least two ethylenically unsaturated double bonds, carboxamide, carboxyl or ester groups as functional groups, and also methylenebisacrylamide and divinyl sulfone. The crosslinkers (6) are for example polyether diamine reaction products preferably having from 2 to 50 alkylene oxide units, alkylenediamines such as ethylenediamine, propylene diamine, 1,4-diaminobutane and 1,6-diaminohexane, polyalkylene polyamines having molecular weight. <; 5000 for example diethylenetriamine, triethylenetetramine, dipropylenetriamine, tripropylenetetramine, dihexamethylenetriamine and aminopropylethylenediamine, alkylene glycols, polyalkylene glycols or mixtures thereof with monoethylenically unsaturated carboxylic acids, esters of monoethylenically unsaturated carboxylic acids, monoethylenically unsaturated carboxylic acid amides, monoethylenically unsaturated carboxylic acid anhydrides. These reaction products and their preparation are described in EP-A-873 371 and are expressly mentioned for use as crosslinkers.

Particularly preferred crosslinkers are the reaction products mentioned herein with maleic anhydride with α, β-polyetherdiamines having a molar mass of 400 to 5000, the reaction products of polyethylene imines having a molar mass of 129 to 50,000 with maleic anhydride and also the reaction products of ethylenediamine or triethylenetetramine with maleic anhydride in a molar ratio of 1: at least 2. The crosslinkers (6) are preferably compounds of the formula wherein X, Y, Z = 0, NH and Y is additionally = CH2 m, n = 0-4 p, q = 0-45,000, which are obtained by reacting polyetherdiamines, ethylenediamine or polyalkylene polyamines with maleic anhydride. The additional halogen-free crosslinkers of group (7) are at least dibasic saturated carboxylic acids such as dicarboxylic acids and also the salts, diesters and diamides derived therefrom. These compounds can be characterized, for example, by the formula X-CO- (CH 2) n -CO-X wherein X = OH, OR 1, N (R 2) 2 R 1 = C 1 -C 22 alkyl, R 2 = H, alkyl of C? -C22, and n = 0-22. As well as also dicarboxylic acids of the aforementioned formula, it is possible to use, for example, monoethylenically unsaturated dicarboxylic acids such as maleic acid or itaconic acid. The esters of the dicarboxylic acids contemplated are preferably derived from alcohols having from 1 to 4 carbon atoms. Examples of suitable dicarboxylic esters are dimethyl oxalate, diethyl oxalate, diisopropyl oxalate, dimethyl succinate, diethyl succinate, diisopropyl succinate, di-n-propyl succinate, diisobutyl succinate, dimethyl adipate, diethyl adipate and diisopropyl adipate or Michael addition products containing at least two ester groups and formed from polyetherdiamines, polyalkylene polyamines or ethylenediamine and esters of acrylic acid or methacrylic acid with, in each case, monohydric alcohols having 1 to 4 carbon atoms. Examples of suitable esters of ethylenically unsaturated dicarboxylic acids are dimethyl maleate, diethyl maleate, diisopropyl maleate, dimethyl itaconate and diisopropyl itaconate. It is also possible to use substituted dicarboxylic acids and their esters such as tartaric acid (form D, L and as racemate) and also tartaric esters such as dimethyl tartrate and diethyl tartrate. Examples of suitable dicarboxylic anhydrides are maleic anhydride, itaconic anhydride and succinic anhydride. Useful crosslinkers (7) also include, for example, dimethyl maleate, diethyl maleate and maleic acid. The crosslinking of the amino-containing compounds with the aforementioned crosslinkers takes place with the formation of the amide groups or, in the case of amides such as adipamide, by transamidation. The maleic esters, monoethylenically unsaturated dicarboxylic acids and their anhydrides can effect crosslinking by formation of carboxamide groups and by addition of NH groups of the component to be crosslinked (polyamidoamines, for example) in the form of a Michael addition. At least dibasic saturated carboxylic acids of class (7) crosslinkers include, for example, tri- and tetracarboxylic acids such as citric acid, propane tricarboxylic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, butacarboxylic acid and diethylenetriaminpentaacetic acid. The useful crosslinkers of the group (7) further include the salts, esters, amides and anhydrides derived from the carboxylic acids mentioned above, for example, dimethyl tartrate, diethyl tartrate, dimethyl adipate and diethyl adipate.

Useful crosslinkers of group (7) further include polycarboxylic acids obtainable by polymerizing monoethylenically unsaturated carboxylic acids, anhydrides, esters or amides. Examples of suitable monoethylenically unsaturated carboxylic acids are acrylic acid, methacrylic acid, fumaric acid, maleic acid and / or itaconic acid. Examples of useful crosslinkers are therefore polyacrylic acids, copolymers of acrylic acid and methacrylic acid or copolymers of acrylic acid and maleic acid. Illustrative comonomers are vinyl ether, vinyl formate, vinyl acetate and vinyl lactam. Additional useful crosslinkers (7) are prepared for example by free radical polymerization of anhydrides such as maleic anhydride in an inert solvent such as toluene, xylene, ethylbenzene, isopropylbenzene or solvent mixtures. Furthermore, homopolymers or copolymers of maleic anhydride are suitable, for example copolymers of acrylic acid and maleic anhydride or copolymers of maleic anhydride and an olefin of C2- to C3o ~. Examples of preferred crosslinkers (7) are copolymers of maleic anhydride and isobutene or copolymers of maleic anhydride and diisobutene. Copolymers containing anhydride groups can optionally be modified by reaction with Ci to C20 alcohols of ammonia or amines and can be used as crosslinkers in that form.

Examples of preferred polymeric crosslinkers (7) are copolymers of acrylamide and acrylic esters, for example hydroxyethyl acrylate or methyl acrylate, the molar ratio of acrylamide and acrylic ester varies in the range of 90:10 to 10:90. In addition, these copolymers, terpolymers can be used, an example of useful combinations are acrylamide, methacrylamide and acrylate / methacrylate. The molar mass M "of the homo- and copolymers can be up to 10,000, preferably from 500 to 5000. Polymers of the type mentioned above are described, for example, in EP-A-0 276 464, US-A-3 810 834, GB -A-1 411 063 and US-A-4 818 795. At least the dibasic saturated carboxylic acids and the polycarboxylic acids can also be used as crosslinkers in the form of the alkali metal or ammonium salts. Preferably it is given to use the sodium salts. The polycarboxylic acids can be partially neutralized, for example to an extent of 10 to 50 mol%, or otherwise completely neutralized. Useful halogen-free crosslinkers of group (8) may include for example monoethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and crotonic acid and the amides, esters and anhydrides derived therefrom. The esters can be derived from alcohols from 1 to 22, preferably from 1 to 18, carbon atoms. The amides are preferably unsubstituted, but can support an alkyl substituent of C? -C22. Preferred crosslinkers (8) are acrylic acid, methyl acrylate, ethyl acrylate, acrylamide and methacrylamide. The group's useful halogen-free crosslinkers (9) include for example dialdehydes or their hemiacetals or acetals as precursors, for example glyoxal, methylglyoxal, malonaldehyde, succinaldehyde, maleyaldehyde, fumaraldehyde, tartaraldehyde, adipaldehyde, 2-hydroxyadipaldehyde, furan-2,5-dipropionaldehyde, 2-formyl-2 , 3-dihydropyran, glutaraldehyde, pimelaldehyde and also aromatic dialdehydes such as, for example, terephthalaldehyde, o-phthalaldehyde, pyridine-2,6-dialdehyde or phenylglyoxal. But it is also possible to use homo- or copolymers of acrolein or methacrolein having molecular masses from 114 to about 10,000. Useful comonomers include, in principle, all water-soluble comonomers, for example acrylamide, vinyl acetate and acrylic acid. The aldehyde starches are similarly useful as crosslinkers. The group's useful halogen-free crosslinkers (9) include for example diketones or hemiketals or corresponding ketals as precursors, for example ß-diketones such as acetyl ketone or cycloalkan-1, n-diones such as, for example, cyclopentan-1,3-dione and cyclohexane-1,4-dione. But it is also possible to use homopolymers or copolymers of methyl vinyl ketone having molar masses of from 140 to about 15,000. Useful comonomers include in principle all water-soluble monomers, for example, acrylamide, vinyl acetate and acrylic acid. It will be appreciated that mixtures of two or more crosslinkers can also be used. The superabsorbents according to the invention are preferably prepared using in particular crosslinkers that are free of organic halogen. It is therefore preferable to use halogen-free crosslinkers to prepare cross-linked polymers II which are each insoluble in water. The crosslinkers described above can be used either alone or as a mixture in the reaction with water-soluble amino-containing polymers or polyalkylene polyamines. The crosslinking reaction is in all cases carried out until the resulting products are still dilated, but not dissolved in water. The crosslinking reaction is carried out by heating the reaction components at room temperature to 220 ° C, preferably 50 to 180 ° C. If the crosslinking reaction is carried out in an aqueous medium at about 100 ° C, it is advantageous to remove the resulting condensate (water, lower alcohols, ammonia, amines) by distillation together with the dilution water present until the reaction mixture It has become solid. The polymeric film is then pulverized and, if appropriate, ground while cooling with dry ice. Additional preference is given to polymers II which have not had an additional crosslinker thereto, but which are capable of self-crosslinking on account of their comonomers. Such vinylformamide copolymers are thermally crosslinked after their hydrolysis. The self-crosslinking comonomers are acrylic acid, methacrylic acid, acrylic esters, methacrylic esters and their homologs and also acrylamide and acrylonitrile. The self-crosslinking copolymers are based in particular on acrylic esters, methacrylic esters or homologs thereof, but also on acrylic acid, methacrylic acid or homologs thereof. The N-vinylformamide fraction is usually within the range of 50 to 99 mol%, and the comonomer fraction is usually within the range of 1 to 50 mol%. It is particularly advantageous to have a comonomer fraction of 5 to 15 mol% and a fraction of N-vinylformamide of 85 to 95 mol%, the monomer fractions are always added up to 100 mol%. Such copolymers are first virtually completely saponified under basic, optionally desalted and subsequently crosslinked conditions of 80 to 220 ° C, preferably 120 to 180 ° C. If desired, the crosslinking of such copolymers can be run until the further addition of polyvinylamines or polyethylene imines. Polyvinylamine was also observed to undergo thermal auto-crosslinking. This is believed to be due to the remaining formamide groups even after the hydrolysis, and also due to the condensation by elimination of ammonia to form secondary amines. The ratio of formamide groups to amino groups may be within the range of 30/70 to 0/100, and is preferably within the range of 15/85 to 5/95. The auto-crosslinking of polyvinylamine is carried out in an aqueous solution of 100 to 200 ° C, preferably 150 to 180 ° C. In a preferred embodiment, the polyvinylamine to be cross-linked is applied to thin films. Preference is given to the self-crosslinking of polyvinylamine having a K value of 70-200, particularly preferably 100-150, since this leads to hydrogel-forming polymers having advantageous properties. The ratios in which the two hydrogel forming polymers I and II are mixed together depending in particular on the density of the acid or amine groups (eq / g) and the acid or base strengths as well as other factors. The mixing ratios can vary from 20: 1 to 1:20 (by weight). Preference is given to mixing ratios within the range of 10: 1 to 1:10, particularly preferably within the range of 7: 3 to 3: 7.

There are in principle the following possibilities to prepare the mixture: a) mix the powders separately prepared, b) mix the gels containing water, c) mix a gel containing water with a powder, d) add powders or gels of one component to the reaction mixture for preparing the other component, e) specifically constructing a shell type particle where one component is the core and the other the shell. a) Powders prepared separately can be mixed using any commercially available assembly by mixing powders. The particles to be mixed are from 10 to 200 μm, preferably from 100 to 850 μm, in size. The two components to be mixed can have identical or different particle sizes. The use of particle sizes different from the two components can be advantageous in those differences in the absorption rate or ion exchange rate of the two components can be accommodated in that way. It may also be advantageous to use one component in a relatively rough divided form and the other in a very finely divided form, as well as the finely divided component agglomerates on the surface of the rough component. If appropriate, this process can be expanded by the addition of agglomeration aids such as, for example polyethylene glycols, water and / or polyols. A further possibility is to use both components in the form of very finely divided powders and to agglomerate them with the help of the agglomeration aids as listed above to form agglomerates of 100 μm to 1500 μm in size. It may also be advantageous to combine this agglomeration with a post-crosslinking surface in such a way that the post-crosslinking will also bring about agglomeration. The advantage of agglomeration (by any variant) is that this generates particles containing the two components together, so that the two components can not be separated when this mixture is used in sanitary articles, for example. This effect is particularly marked in the case of mixtures comprising very different particle sizes for the two components. The separation of the two components has the consequence of long-term trajectories in the ion exchange process leading to locally strong acidic or basic pH values. This behavior is not acceptable for use in hygienic articles. Agglomeration also offers the advantage that high absorption rates can be updated without the use of very finely divided powders, which are undesirable due to dusting. b) Another way to avoid the problem described above of separating the component is to intimately mix the aqueous gels with each other and subsequently dry, grind and, if appropriate, sift them. This provides particles that contain the two components firmly attached to each other, so that separation of the two components is not possible. It is likely that strong ionic interactions develop at the boundary of the layer between the two gel components and firmly bond the basic and acidic components together (see DE-A-19640329). The formation of a classic polyelectrolyte complex is unlikely, since the two polyelectrolytes are each part of a separate network. Since both components are produced as aqueous gels, it is advantageous to use a mixture of these gels. But it is also possible to use gels obtained by dilating dry products with water. It may furthermore be advantageous to partially dry the products thus produced from the components previously mixed. The mixture itself can be made using various types of equipment, for example meat grinders, kneaders, extruders, including planetary coil extruders, or mixers. The apparatuses used have been homogeneously secured, finely divided of the two components were mixed without damaging the network structure of the gels by excessive cutting. The water content of the mixed gels is within the range of 5 to 99.8% by weight, preferably from 60 to 99% by weight. The water content of the two mixed gels can be identical or otherwise different. Another advantage with this variant is the fact that it is quick to dry, easier to grind, it also requires non-separate drying steps and the gel mixtures obtained have high gel strength and therefore easier handling. c) An additional possibility is to mix the gel of one component with the powder of the other component. The procedure and equipment used are the same as in case b). It is likely that this case generates different structures within a particle than if the gels are mixed together. In the latter case, the particles will have a structure in which the components are present side by side in comparatively large domains. The size ratio of the domains is decisively determined by the mixing ratio and the solid contents of the gels used and by the mixing intensity. In the first case, the component added as a powder will have an island structure in a matrix of the component used in the form of a gel. Depending on the desired property spectrum, it may be advantageous to update one structure or the other. d) A further way to obtain non-separated products is to add powders or gels of one component to the reaction mixture of the other component. For example, the addition of the polymer I (polyacrylic acid, for example) as a powder or gel to the polyvinylamine solution and subsequent cross-linking of the polyvinylamines leads to mixtures having advantageous properties. This crosslinking can be carried out by adding a crosslinking or thermally as self-crosslinking. Similarly, the addition of the crosslinked polyvinylamine as a powder or gel to a polymer I (e.g., polyacrylic acid) and subsequent crosslinking provides blends having advantageous properties. Care must be taken to ensure in this connection that unwanted reactions take place. For example, by adding crosslinked polyvinylamine to an acrylic acid reaction mixture, the crosslinker and initiator could immediately establish a Michael addition between the primary amino groups of the gel and the acrylic acid. Subject to the condition that no unwanted reactions can take place, it is possible to add the powder or otherwise a gel to the reaction mixture of the other component at any time of the reaction sequence. This variant is likely to generate products whose boundary layer between the components has a different structure than in the case of gel or powder mixtures. One of the two components is present here at least in a still partially uncrosslinked state or even as a monomeric mixture. As a result, more regular structures that have relatively strong interactions through the polyelectrolyte complexes can develop in the boundary layer, and it is likely that the boundary layer will be significantly thicker than in the case of the preceding variants. This effect would improve gel stability and also predispose the range of properties that is feasible towards the post-crosslinking surface. e) Another possibility is the formation of a core-shell structure. For this, the particles of a component are coated, for example, sprayed, with a reaction mixture to prepare the second component. After or during the reaction the core-shell product obtained is dried. In order to provide certain layer thickeners, it may be necessary to repeat the coating a number of times. On the other hand, it is also conceivable that such a process can be used to build multilayer particles comprising alternating layers of two components. A particularly suitable way to build complex layer structures in particular as well as simple ones is a fluidized bed process. The essential advantage of such a process is that it becomes possible to produce defined structures having uniform and specifically adjustable layer thicknesses. The polymers that form hydrogel (polymer I, polymer II or mixtures of polymers I and II) can be dried according to various processes known to those skilled in the art. Examples of useful drying processes are drying by thermal convection, for example tray, chamber, duct, flat sheet, disk, rotating drum, free fall tower, foraminous web, flow, fluidized bed, moving bed, ball bed drying and labe, thermal contact drying such as heater, drum, band, foraminous cylinder, screw, contact disc drying and dropping, radioactive drying such as infrared drying, dielectric drying such as microwave drying, and freeze drying. To avoid undesired decomposition and crosslinking reactions, it may be advantageous to dry under reduced pressure, under a protective gas atmosphere and / or under mild thermal conditions wherein the temperature of the product does not exceed 120 ° C, preferably 100 ° C. Particularly suitable drying processes are by band drying (vacuum) and drying by blade. The dried hydrogel forming polymers are, if appropriate, pre-pulverized and then ground according to the processes known to those skilled in the art, for example by means of a roller mill or a hammer mill. Subsequent screening is used to adjust the particle size distribution, which generally ranges from 100 to 1000 μm, preferably from 120 to 850 μm. The large particles can be rectified, the smaller particles can be recycled in the production processes. It may also be sensitive to mix the above-described mixtures with commercially available superabsorbents, ie add acidic or basic crosslinked polymers whose acidic or basic groups are at least 50% neutralized. The fraction of these commercially available superabsorbents would be less than 50%, preferably less than 25%.

In addition, polymers I and II can in a conventional form be post-crosslinked in aqueous gel phase or post-crosslinked surface such as dried, milled and classified polymer particles. In a preferred embodiment of the invention, the absorption properties of the resulting mixtures of the polymers I and the polymers II are further improved by subsequent surface crosslinking. This can take the form of exclusive crosslinking of polymers I, exclusive crosslinking of polymers II or crosslinking of a homogeneous mixture of the two polymer varieties. To this end, the compounds capable of reacting with the functional groups of the crosslinked polymers are applied to the surface of the hydrogel particles, preferably in the form of an aqueous solution. The aqueous solution may contain organic solvents miscible in water. Suitable solvents are alcohols such as methanol, ethane, i-propanol or acetone. Suitable surface post-crosslinkers include, for example: di- or polyglycidyl compounds such as diglycidyl phosphonates or glycidyl ether of ethylene glycol, ethers of bischlorohydrin or polyalkylene glycols, glycidol or epichlorohydrin, alkoxysilyl compounds, polyaziridine compounds, aziridine based in polyethers or substituted hydrocarbons, for example bis-N-aziridinomethane, polyamines or polyamidoamines and also their reaction products with epichlorohydrin, - polyols such as ethylene glycol, 1,2-propanediol, 1, -butanediol, glycerol, methyltriglycol, polyethylene glycols having an average molecular weight M "of 200-10,000, di- and polyglycerol, pentaerythritol, sorbitol, the ethoxylates of these polyols and their esters with carboxylic acids or carbonic acid such as carbonate of ethylene or propylene carbonate, carbonic acid derivatives such as urea, thiourea, guanidine, dicyandiamide 2-oxazolidinone and its derivatives, bisoxazoline, polyoxazolines, di- and polyisocyanates, - di- or polyaldehydes such as, for example, glyoxal, succinaldehyde or aldehyde starch, -di- or polyketones - compounds having two or more more activated double bonds capable of recording a Michael addition, for example, divinyl sulfone, methylenebisacrylamide or ethylene glycol dimethacrylate, di- and polycarboxylic acids and also their anhydrides, esters, acyl chlorides and nitriles, for example oxalic acid, glutaric acid, adipic acid, maleic anhydride, tartronic acid, malic acid, tartaric acid or citric acid, - di- and poly-N-methylol compounds such as, for example, methylenebis (N-methylolmethacrylamide) or melamine-formaldehyde resins, - di- and polyhalogen compounds such as a,? dichloropolyalkylene glycols, a ,? or vicinal dichloroalkanes for example, 1,2-dichloroethane, 1,2-dichloropropane, 1,3-dichlorobutane or 1,6-dichlorohexane, - compounds having two or more more blocked isocyanate groups, for example trimethylhexamethylene diisocyanate blocked with 2 , 2, 6, 6-tetramethylpiperidin-4-one, - monoethylenically unsaturated carboxylic acids, for example (meth) acrylic acid or crotonic acid, and their esters, amides and anhydrides. If necessary, acidic catalysts can be added, for example p-toluenesulfonic acid, phosphoric acid, boric acid or ammonium dihydrogenphosphate. Particularly useful post-crosslinkers are di- or polyglycidyl compounds such as ethylene glycol diglycidyl ether, the reaction products of the polyamidoamines with epichlorohydrin and 2-oxazolidinone, which are capable of reacting both amino and carboxyl groups to effect crosslinking. The crosslinked solution is preferably applied by spraying with a solution of the crosslinker in reaction mixers or by mixing and drying the equipment. Conventional mixing assemblies suitable for spraying the crosslinked solution on the polymer particles include for example Patterson-Kelly mixers., DRAIS turbulence mixers, Lodige mixers, NARA blade mixers, screw mixers, disc mixers, fluidized bed mixers, Schugi mixers (Flexo-Mix) or PROCESSALL. Small amounts can be post-crosslinked on a laboratory scale using kitchen mixers, for example a WARING mixer. The spray of the crosslinked solution can be followed by a heat treatment step, preferably in a downstream dryer, of 80 to 120 ° C, preferably 80 to 190 ° C, particularly preferably 100 to 160 ° C, during a period of 5 minutes to 6 hours, preferably 10 minutes to 2 hours, particularly preferred 10 minutes to 1 hour, during which not only the cracking products, but also solvent fractions can be removed. The drying can also take place in the mixer by itself, by heating the cover or by blowing in a preheated carrier gas. If particles comprising structures characterizing contiguous domains or areas of polymers I and polymers II are present, additional crosslinking of this domain or area boundaries can also be effected by means of a heat treatment without the addition of a crosslinker. The water content of particles before this heat treatment is preferably within the range of 0 to 50% by weight, particularly preferably within the range of 1 to 30% by weight, more preferably within the range of 2 to 20% by weight. weight. The temperature in this tempering step is within the range of 80 to 230 ° C, preferably 80 to 190 ° C, particularly preferably within the range of 100 to 160 ° C, for a period of 5 minutes to 6 hours, preferably from 10 minutes to 2 hours, particularly preferably 10 minutes to 1 hour. The heat treatment step can take place after drying the particles in a downstream dryer, in which case the desired water content for the particles can be effected by spraying with water or with a mixture of water and one or more solvents organic miscible in water. Preferably, however, the heat treatment step takes place in the course of drying the hydrogel particles, first drying the hydrogel to the desired water content and then subjecting it to heat treatment. The heat treatment may take place in a separate dryer or preferably in the same drying apparatus as is used by drying the hydrogel to the desired water content. Without wishing to be bound by any theory, the inventors believe that this heat treatment causes the acid groups of polymer I to form covalent amide groups with the amino groups of polymer II in the domain or area boundaries, resulting in additional crosslinking. In a particularly preferred embodiment of the invention, the hydrophilicity of the particle surface of the mixtures of the polymers I and polymers II is further modified by the formation of the complexes. The formation of the complexes in the outer shell of the hydrogel particles is effected by spraying with solutions of divalent or more highly valent metal solutions and / or divalent or more highly valent anions wherein the metal cations are capable of reacting with the Functional groups of the anionic polymer and the polyvalent anions are capable of reacting with the functional groups of the cationic polymer, to form complexes. Examples of divalent or more highly-valent metal cations are Mg2 +, Ca2 +, Al3 + Sc3 \ Ti4 +, Mn2 +, Fe2 + 3+, Co2 +, Ni2 +, Cu + 2+, Zn2 +, Y3 +, Zr4 +, Ag +, La3 +, Ce4 +, Hf4 + and Au + 3 +, the preferred metal cations are Mg2 +, Ca2 +, Al3 +, Ti4 +, Zr + and La3 +, the particularly preferred metal cations are Al3 +, Ti + and Zr4 +. Examples of divalent or more highly valent anions are sulfate, phosphate, borate and oxalate. Of the metal cations and polyvalent anions mentioned, any salt is suitable which has sufficient solubility in the solvent to be used. Useful solvents for the salts are water, alcohols, DMF, DMSO and mixtures thereof. Particular preference is given to water and water / alcohol mixtures, for example water / methanol, or water / 1,2-propanediol. The spraying of the saline solution onto the particles of the mixture of polymers I and II that form hydrogel can take place before and after the surface crosslinking of the particles. In a particularly preferred process, the spraying with the metal salt solution takes place in the same stage as the spray with the crosslinked solution, the two solutions being sprayed separately in succession or simultaneously through two nozzles, or the crosslinker and the salt solutions they can be sprayed together through a single nozzle. Optionally, the particles of the mixture of polymers I and polymers II can be further modified by mixing finely divided inorganic solids, for example, silica, bentonites, aluminum oxide, titanium dioxide and iron (III) oxide, to further expand the effects of the surface after treatment. Particular preference is given to the mixture of hydrophilic silica or aluminum oxide having an average primary particle size of 4 to 50 nm, and a specific surface area of 50 to 450 mVg. The mixture of highly divided inorganic solids preferably takes place after surface modification through crosslinking / build, but may also be carried out before or during these surface modifications. In a number of process steps, it may be sensitive to use additives. The additives for the purposes of the present invention are finely divided, powdery or fibrous, organic or inorganic substances which are inert towards the production conditions of the components and mixtures. Examples of such additives are: finely divided silicon dioxide, pyrogenic silicas, silicas precipitated in hydrophilic or hydrophobic modifications, zeolites, titanium dioxide, zirconium dioxide, talc, bentonites of any kind, cellulose, silicates of any kind, grain fluorine guar, tara grained fluorine, caroba grained fluorine, any kind of starch, clay, barium sulfate, calcium sulfate, synthetic and natural fibers. Both can be used as processing aids and as a carrier material. The gel to be handled in the course of the production of mixtures according to the invention are all more or less tacky. To overcome this disadvantage, it may be sensitive, especially in the spraying, mixing or drying step, to add from 0.1 to 10% by weight of one or more of the aforementioned additives before or during the processing step. This measure serves to coat the surface of the gel with the finely divided additive and thus decreases or at least drastically reduces the stickiness. This additization also has an effect on the properties of the final product. The fact that the dry powder particles are coated with the additive to the surface improves the fluidity of the resulting powders. In addition, dry gels tend to drink water, especially in contact with a humid atmosphere, and to bind together as a result. The addition of the aforementioned additives also reduces this clumping effect. It can therefore be sensitive to add such additives to the final product only. This is the case when they are not required in the preceding processing stages. To enlarge the surface area, to shorten the diffusion trajectories and to make the functional groups of the gels more easily accessible, it may be sensible to generate the aforementioned acidic or basic gels in a carrier. Such a carrier may also have a large specific surface area. The aforementioned additives have this property, especially pyrogenic silicas, bentonites and talc are preferred. To prepare such acidic or basic components, the carrier material can simply be added to the reaction mixture during the production of the components. Alternatively, the carrier material can be specifically coated with the reaction mixture, for example by spraying in a fluidized bed. The amounts of the carrier material used are within the range of 5% to 80%. Surfactants and blowing agents can also be used as assistants. The following test methods were used to investigate the polymer blends of the invention: CRC (Centrifugal Retention Capacity): CRC I is determined by weighing 0.2 g of the polymer powder into a 60 x 85 mm size tea bag, which is subsequently heat sealed. The tea bag is then placed in an excess of 0.9% by weight of sodium chloride solution (at least 0.83 liters of saline / 1 g of polymer powder.) After a dilation time of 30 minutes, the bag of tea is removed from the saline and centrifuged at 250 g for three minutes.The centrifuged tea bag is weighed to determine the amount of fluid retained by the polymer powder.

PUP 0.7 psi (Performance Under Pressure 0.7 psi): The test method to determine the PUP 0.7 psi (pound / square inch, 0.7 psi = 4826.5 Pa) is described in U.S. Patent 5,599,335.

PUP 1.4 psi (Performance Under Pressure 1.4 psi): PUP 1.4 psi is determined similarly to PUP 0.7 psi, except under a pressure of 1.4 psi (9653 Pa).

PUP 0.014 psi (Performance Under Pressure 0.014 psi): PUP 0.014 psi is determined similarly to PUP 0.7 psi, except that the pressure is reduced to 0.014 psi (96.5 Pa), that is, it is carried out without weight, only with the insert plastic for the weight.

SFC (Saline Flow Conductivity): The SFC test method is described in the US ,599,335.

SFC index (Saline Flow Conductivity Index): The SFC index is obtained from three SFC measurements under different pressures according to the following formula: SFC index = [SFC (0.3 psi) .107 g / cm3s]. ([SFC (0.6 psi). 107 g / cm3s] + [SFC (0.9 psi) - 107 g / cm3s]) The SFC (0.3 psi) corresponds to the SFC described above (0.3 psi = 2068.5 Pa). In the case of SFC (0.6 psi), the expansion of the hydrogel and the flow measurement take place under a pressure of 0.6 psi (4137 Pa), and in the case of SFC (0.9 psi) the expansion and measurement of flow takes place under a pressure of 0.9 psi (6205.5 pa).-PAI (NaCl) (Index of Absorbency of Pressure (NaCl)): The Index of Absorbency of Pressure (NaCl) is determined according to the description of the test method of EPI in EP-A-0 615 736, except that the measurement time is extended up to 16 hours.

PAI (Jayco) (Pressure Absorbency Index (Jayco)): The Pressure Absorbency Index (Jayco) is determined similarly to the previously described determination of the Pressure Absorbance Index (NaCl), except that the fluid to be absorbed is a solution of synthetic urine of the following composition: 1000 g of distilled water, 2.0 g of KCl, 2.0 g of Na2S04, 0.85 g of (NH4) H2P04, 0.15 g of (NH4) HP04, 0.19 g of CaCl2, 0.23 g of MgCl2.

Diffusion of Absorbency Under Pressure: The method to determine the diffusion of absorbency under pressure is similar to the description in EP-A-0712 659, except for the following modifications: The weight of the polymer used is 0.9 g instead of 1.5 g; the polymer sample is measured in the particle size range 106-850 μm; the pressure during the measurement is 0.7 psi (4826.5 Pa) instead of 0.3 psi (2068.5 Pa); the test solution is synthetic urine solution (see PAI) - instead of 0.9% by weight of saline; the measurement time is 4 hours instead of 1 hour, Purge Performance: Purge performance is measured similarly to the purge parameter, the measurement of which is described in EP-A-0 532 002. In the heading of the method for measuring the purge parameter, the purge performance is measured with 2 g of the polymer (particle size distribution 106 - 850 μm) only at a predilation of 10 g of 0.9% by weight of saline / 1 g of the polymer. The measured quantity is the purge distance which indicates the length over which the polymer particles have dilated with the blue test liquid following a test time of 1 hour and the purge capacity corresponding to the amount of liquid additionally absorbed in the sample. this period.

Acquisition Time / Low Rewet Pressure: The test is carried out using laboratory pads. To produce these lab pads11.2 g of hair cellulose and 23.7 g of hydrogel are fluidized homogeneously in an air box and by application of a slight vacuum falling below a mold size of 12 x 26 cm. This composition is then wrapped in tissue paper and compressed for 2 times 15 seconds under a pressure of 20 bar. A laboratory pad produced in this manner is attached to a horizontal surface. The center of the pad is determined and marked. The synthetic urine solution is applied through a plastic plate that has a ring in the middle (inner diameter of the ring 6.0 cm, height 4.0 cm). The plate is loaded with additional weights so that the total load on the pad is 13.6 q / ciX. The plastic plate is placed on the pad in such a way that the center of the pad is also the center of the application ring. 80 ml of the synthetic urine solution are applied three times. The synthetic urine solution is prepared by dissolving 1.14 g of magnesium sulfate-heptahydrate, 0.64 g of calcium chloride, 8.20 g sodium chloride, 20 g of urea in 1 kg of deionized water. The synthetic urine solution is measured in a measuring cylinder and applied in an injection to the pad through the ring on the plate. At the same time, the time is measured until the solution has completely penetrated the pad. The measurement time is recorded as Acquisition Time 1. Thereafter the pad is weighed with a plate for 20 minutes, the load is further maintained at 13.6 g / cm2. Thereafter the plate is removed, 10 g ± 0.5 g of the filter paper (Schleicher &; Schuell, 1450 CV) are placed in the central injection and loaded with a weight (area 10 x 10 cm, weight 3.5 kg) for 15 s. After this period, the weight is removed, and the filter paper is reweighed. The weight difference is observed as Rewet 1. From there on the plastic plate with the application ring is placed back on the pad and the liquid is applied during the second time. The time is observed as Acquisition Time 2. The procedure is repeated as described, but 45 ± 0.5 g of the filter paper is used for the rewet test. Rewetting 2 is observed. The same method is used to determine the Acquisition Time 3. 50 g ± 0.5 g of the filter paper are used to determine Rewet 3.

RAC Factor (Gel Re-Absorption Capacity Factor Cut) The RACF is determined (usually determined double) by mixing 1.2 g of the polymer in an aluminum disk (diameter 4 cm, edge height 3 mm) with 12.0 g of 0.9% by weight of NaCl solution and allowing the sample to expand for 30 minutes, in the covered condition to protect against drying. 1.10 g of the predilated gel is weighed in a Plexiglas cylinder (25 mm in internal diameter and 33 mm in height) whose bottom surface is a 140 μm sieve and covered with a Plexiglas disk. The cylinder with substance and disk is weighed and the weight is observed as Wl. The Plexiglas disk is then loaded with a metallic weight (Plexiglas disk = weight = 245 g, corresponds to a pressure of 50 g / cm2 or 4095 Pa) and the entire measuring unit is placed in a Petri dish 100 mm in diameter and 10 mm in height filled with 13 ml of 0.9% by weight of NaCl solution. After a dilated time of 60 minutes, the measuring unit is lifted off the Petri dish, the weight is removed, the excess of saline adhesion at the bottom of the sieve is cleaned and the measuring cell with dilated gel and Plexiglas disk is retroestimated the weight being observed as W2. The remainder (11 g) of the predilated gel after the deduction of the amount of gel for the double determination described above is transferred in a polyethylene bag 30 x 150 mm in size and the open side of the bag is sealed under vacuum. The bag is fixed in a film bag tester using an adhesive tape and then subjected to a test Roll-Down by turning a roller of 2 kg in weight on itself 50 times (25 times each in opposite directions). The resulting stripped gel is then subjected to the test described above for Absorbency under Pressure at 50 g / cm? to reach the resorption capacity of the stripped gel. The weight of the measuring cell with the gel and the disc before the 60 minute absorption period is observed as W3, and the subsequent absorption weight is observed as W4. The reabsorption capacity factor is then the absorption ratio after absorption before gel stripping, multiplied by 100: Factor RAC = [(W4 - W3) / weight of stripped gel / 10)]. 100 / [(W2 - Wl) / (weight of gel not stripped / 10)] DATGLAP 0.7 psi / 0.9 psi (Required Absorbency Through Gel Layer Against Pressure 0.7 psi / 0.9 psi) The method to determine DATGLAP involves 2 stages. The first stage comprises a measurement of an AUL (Absorption Under Load) at a pressure of 0.7 psi (0.7 psi = 4826.5 Pa), using the same measured cell and the same equipment and virtually the same method as for the determination of PUP 0.7 psi described in US 5,599,335. However, DATGLAP / stage 1 differs from PUP by 2 points: 1. After the test substance has been sprayed on the screen bottom of the measuring cell, the Plexiglas ring placed on is 0.32 cm in height and covered in its upper surface with the same screen structure as the bottom surface of the measuring cell. The cover ring has an external diameter of 5.98 cm, so that it can be moved in the measurement cell without gluing / compressing like the expanded gels, an internal diameter of 4.9 cm and a height of 0.32 cm. The cover ring then has the plastic cover plate placed on top of it with the weight, as described in the aforementioned US patent. . The test fluid used for DATGLAP is not synthetic urine, but 0.9% by weight of saline. After a measurement time of 1 hour, the covered Plexiglass ring remains in the measurement cell and the rest in the gel has, in the second stage, the weight and the plastic cover plate removed from it, and replaced by a new measurement unit of the same design as described above (but of smaller diameter to the appropriate one inside the Plexiglas cylinder of the first measurement stage) and left in place for 4 hours. The measurement of the liquid absorption restarts with time of the second measuring unit being placed in the sieve ring of the first measuring unit. The second measurement cell has the following dimensions: outside diameter = 5.98 cm / internal diameter = 5.03 cm. The test substance distributed on the bottom of the sieve of the second measuring cell is covered beforehand with a Plexiglas disk (5.018 cm in diameter) and loaded with a weight (Plexiglas plate + weight = 1331 g - 67.3 g / cm¿ = 6606 Pa).

DATGLAP = (DAAP-TGL / DAAP-Regulate) - (DAAP-Regular + D.AAP ~ TGL) [g / g] DAAP-TGL = Demanded Absorbance Against Pressure Through the Gel Layer after 4 hours, in [g / g] = measurement value of the second stage with the second measurement cell DAAP-Regular = .Absorbed Demanded Against the Pressure after 1 hour, in [g / g] = measurement value of the first stage with the first measurement cell Preference is given to the polymer mixtures having an SFC index of minus 10,000, preferably > 100,000, especially > 200,000, particularly preferred > 300,000 CRC, PUP 0.014 psi, PUP 0.7 psi and PUP 1.4 psi, PAI (NaCl) and PAI (Jayco) are test methods to characterize the absorption capacity of the polymer mixture for aqueous saline solutions under different confining pressure. SFC, SFC index and Purge Performance describe the permeability of the expanded gel layers. Low Absorbency Diffusion Pressure and DATGLAP are test methods for the combined capture of fluid absorption and transport capacity. The RAC factor characterizes the mechanical stability of the expanded polymer particles. The time of Acquisition / Re-wetting under pressure tests simulates the behavior of the polymer mixture in hygienic articles such as diapers for children or incontinence. Useful for application in hygienic articles are in particular polymer blends having a Pressure Absorbency (NaCl) index of > 100, preferably > 130, especially > 150, particularly preferred > 180, after a dilated time of 16 hours, preferably 4 hours.

, .. *., ... * .- .. * ..,. Preference is given in particular to polymer blends having a Pressure Absorbency Index (Jayco) of at least 150, preferably > 200, especially > 225, particularly preferred > 250, after a dilation time of 16 hours, preferably 4 hours. In addition, polymer blends having an Absorbency Diffusion Under Pressure of at least 30 g / g, preferably > 40 g / g, especially > 45 g / g, particularly preferred > 50 g / g, are advantageous. Also of advantage are polymer blends which provide in the Purge Performance Test a Purge Distance of at least 5 cm, preferably > 8 cm, especially > 10 cm, particularly preferred > 15 cm, and a Purge Capacity of at least 5 g, preferably > 8 g, especially > 10 g, particularly preferred > 13 g. Preference is also given to polymer blends that in Time / Rewet Acquisition Under Pressure Test Provided in a Acquisition Time 3 of not more than 25 s, preferably < 20 s, especially < 15 s, more preferably < 10 s, and a Rewet 3 of not more than 9 g, preferably < 5 g, especially < 3 g, particularly preferred < 2 g. Preference is further given to polymer blends that provide a RAC factor of at least 80, preferably > 90, especially > 100 and particularly preferred > 120 Additionally of the advantage are polymer blends having a DATGLAP of at least 50 g / g, preferably > 65 g / g, especially > 80 g / g, more preferably > 90 g / g. Particular preference is given to polymers that combine a plurality of these preferred properties. For example, polymer blends having an SFC index > ,000 and a Purge Distance of > 5 cm and a capacity of Purge of at least 5 g are preferred. Particular preference is given to polymer blends having an Acquisition Time 3 of not more than 25 s and a Rewet 3 of not more than 9 g and an SFC > 10,000 and / or a Low Absorbency Diffusion Pressure of > 30 g / g. Preference is given to polymer blends having a SFC index of > 1000, a PAI of > 150 after a dilation time of 16 hours, a Diffusion of .Absorbent Under Pressure of at least 30 g / g, a Purge Distance of > 5 cm, a Purge Capacity of > 5 g, a Time 3 of Acquisition of no more than 25 s and one Rewet 3 of no more than 9 g. Preference is given to polymer blends comprising polymers I based on acrylic acid and / or methacrylic acid. Preference is given to polymer mixtures whose polymer I is a crosslinked polyacrylic acid wherein from 0 to 50% of the carboxylic acid groups are present as alkali metal and / or ammonium salt.

Preference is likewise given to polymer blends comprising crosslinked copolymers of acrylic acid or methacrylic acid with vinylsulfonic acid or acrylamidopropanesulfonic acid as polymers I. Preference is furthermore given to polymer blends wherein such polymers I have been cross-linked with diacrylates or methacrylates of oligo- or polyethylene glycol whose molecular weight is within the range of 200 to 1000. Preference is given to polymer blends in which polymer II is a polyethyleneimine, an ethylene imine grafted polyamidoamine and / or a grafted ethylene imine polyamine which are each crosslinked. Preference is also given to polymer blends whose polymer II is a cross-linked polyvinylamine. Preference is furthermore given to polymer blends whose polymer II is obtained by copolymerization of vinylformamide and one or more monoethylenically unsaturated compounds, subsequent hydrolysis with or without desalting and subsequent crosslinking. Preference is given to polymer blends whose polymer II is a graft copolymer of vinylformamide in polymeric compounds which are subsequently subjected to hydrolysis with or without desalting and crosslinking. Preference is given to polymer blends whose polymer II is a copolymer of vinylformamide and mono- and / or polyethylenically unsaturated mono- and polycarboxylic acids which are subsequently subjected to hydrolysis with or without desalting and self-crosslinking by heating, ie without crosslinker. Preference is given to polymer blends whose polymer II is a copolymer of vinylformamide and mono- and / or polycarboxylic monoethylenically unsaturated acids which are subjected to hydrolysis with or without desalting, cross-linking by heating and further subsequent cross-linking with a cationic polymer or copolymer based on polyvinylamine or polyethyleneimine and / or with minus a bifunctional crosslinker. Preference is furthermore given to polymer blends whose polymer II is a polyethylenimine, a grafted polyamidoamine of ethyleneimine or a grafted polyamine of ethyleneimine which is a polymer analogously modified by reaction with α, β-unsaturated carboxylic acids or esters or by Strecker reaction and subsequently thermal reticulation with itself or at least a crosslinker. Additional preference is given to polymer blends whose polymer II is obtained by crosslinking a polyvinylamine having a K value of from 40 to 220, especially from 70 to 160. Preference is further given to polymer blends whose polymer II is prepared with one or more crosslinkers of groups (1), (5), (6), (7), (8) and (9). Preference is given to polymer blends having a ratio of the acid portions to the total sum of amino / imino portions of 2: 1 to 1: 8. Preference is given to polymer blends obtained by mixing polymer gel I and polymer gel II. Particular preference is given to polymer blends obtained by mixing polymer gel I and polymer powder II or polymer powder I and polymer gel II. Particular preference is given to polymer blends obtained by the addition of a mixture component I or II as a powder to the reaction mixture of the other component. Preference is furthermore given to polymer blends including polymer powder II, polymer powder II and agglomeration aids. Preference is given to polymer blends obtained by mixing post-crosslinked surface polymer I and post-crosslinked surface polymer II. The resulting intraparticulate mixtures having a domain structure, an island structure and / or a core-shell construction are preferred. Preference is furthermore given to polymer blends comprising a mixture of agglomerated post-crosslinked surface powder. The polymer blends according to the invention have good application properties. They have an advantageous SFC index, good PAI values not only for sodium chloride but also for Jayco. They also exhibit excellent Absorbency Diffusion Under Pressure. In addition, they give good results in the Purge Performance Test. Its good results in the Acquisition Time / Rehumidification Test under Pressure are also particularly outstanding. The polymer blends according to the invention are remarkable for the outstanding absorption capacity for water and aqueous salt solutions, for the high permeability of the expanded gel layers and for the high mechanical stability of the expanded polymer particles and are for thus very useful as absorbers for water and aqueous fluids, especially body fluids such as urine or blood, for example, in hygienic articles such as diapers for children and adults, sanitary napkins, tampons and the like. But, they can also be used as soil improvers in agriculture and horticulture, as moisture binders for cable lining and for heavy aqueous waste. The following examples illustrate the invention.

Example 1 a) Preparation of a crosslinked polyacrylic acid 350 g (4.86 mole) of acrylic acid and 3.84 g of polyethylene glycol diacrylate of a polyethylene glycol of molar mass 400 and 0.88 g of sodium peroxodisulfate are dissolved in 1046.16 g of distilled water. The solution is transferred to a 2 1 Dewar flask at room temperature. The Dewar bottle is sealed with a stopper equipped with a gas outlet and a gas inlet tube that reaches the bottom. The nitrogen is passed through the gas inlet tube for 30 minutes to remove the dissolved oxygen. 2.92 g of 0.3% by weight of the ascorbic acid solution is then added as a co-initiator and mixed homogeneously with a vigorous stream of nitrogen. After the polymerization has started, the nitrogen stream is turned off and the gas inlet tube is retracted from the Dewar bottle. After reacting overnight, a portion of the resulting gel block is pulverized in a meat grinder and dried overnight at 85 ° C under reduced pressure in a vacuum drying cabinet. The second portion is used for additional experiments without additional treatment. The drying gel is milled and classified into the particle size fraction from 100 μm to 850 μm. b) The preparation of a polyvinylamine is cross-linked with ethylene glycol diglycidyl ether. 2241 g of an aqueous polyvinylamine solution of 12.3% by weight (K 85) are mixed homogeneously at room temperature with a solution of 13.77 g of ethylene glycol diglycidyl ether in 100 g of distilled water. The mixture is subsequently heated to 75 ° C in a water bath for 2 hours. A portion of the resulting gel is directly used for further experiments, the rest was dried overnight at 85 ° C under reduced pressure. The product obtained was milled and classified into the particle size fraction from 100 μm to 850 μm. c) Preparation of the powder mixture. In each case 10 g of the classified powder product obtained according to a) and b) are mixed homogeneously.

Example 2 Preparation of a gel-gel mixture 86.40 g of a non-dried polyacrylic acid gel prepared according to Example la) and 157.30 g of a non-dried polyvinylamine gel prepared according to Example Ib) were mixed intimately with each other by passing it 3 times together through a commercially available meat grinder. The gel mixture obtained was dried at 85 ° C overnight under reduced pressure. After grinding, the particle size fraction from 100 μm to 850 μm was classified.

Example 3 64.8 g of non-dried polyacrylic acid gel was prepared according to Example la) and 183.5 g of non-dried polyvinylamine gel prepared according to Example Ib) are mixed intimately with each other by passing them 3 times together through a water mill. meat commercially available. The gel mixture obtained was dried at 85 ° C - overnight under reduced pressure. After grinding, the particle size fraction from 100 μm to 850 μm was classified.

Example 4 100 g of an aqueous polyvinylamine solution of 12.5% by weight (K 85) and a solution of 0.63 g of ethylene glycol diglycidyl ether in 4.38 g of distilled water were mixed homogeneously at room temperature. 12.5 g of the pulverulent crosslinked polyacrylic acid prepared according to Example la) are then likewise mixed homogeneously under vigorous stirring. The reaction mixture was heated to 75 ° C in a water bath for 2 hours. The gel obtained was pulverized, dried overnight at 85 ° C under reduced pressure, milled and classified into the particle size fraction from 100 μm to 850 μm.

Example 5 a) 100 g of an aqueous polyvinylamine solution of 13.6% by weight (K 85) and a solution of 0.41 g of N, N'-methylenebisacrylamide in 9.93 g of distilled water were mixed homogeneously at room temperature. The reaction mixture was heated to 75 ° C in a water bath for 2 hours. The gel obtained was pulverized, dried overnight at 85 ° C under reduced pressure, milled and classified into the particle size fraction from 100 μm to 850 μm. b) In each case 10 g of the classified powder product obtained according to) and 5a) are mixed homogeneously.

Example 6 a) 100 g of an aqueous polyethylene imine solution of 37. 4% by weight (MW approximately 500,000) were mixed homogeneously with 2.99 g of ethylene glycol diglycidyl ether at room temperature. Then it was heated to 75 ° C in a water bath for 2 hours. A portion of the obtained gel was used directly for additional experiments, the rest was dried overnight at 85 ° C under reduced pressure. The product obtained was milled with dry ice and classified into the particle size fraction from 100 μm to 850 μm. b) In each case 10 g of the classified powder product obtained according to the) and 6a) were mixed homogeneously. The advantageous application properties of the polymer mixtures of Examples 1 to 6 according to the invention are compiled in Table 0. Table 0: Table 0: Example 7 a) A polyethylene container of 10 liters capacity, well insulated by foamed polymeric material, was charged with 3450 g of deionized water and 1400 g of acrylic acid. To this solution was added 14 g of allyl methacrylate with stirring, and the solution is quenched by passing nitrogen therethrough. At a temperature of about 10 ° C, the initiators, which consist of 0.57 of 2,2'-azobisamidinopropane dihydrochloride, dissolved in 50 g of deionized water, 69 mg of hydrogen peroxide, dissolved in 50 g of deionized water, and also 27 mg of ascorbic acid, dissolved in 50 g of deionized water, are added in succession and stirred. The reaction solution is then allowed to remain without stirring, and the polymerization temperature is raised to about 92 ° C. A solid gel was obtained. b) 1000 g of an aqueous polyvinylamine solution of 6% by weight (K 137) and a solution of 4.8 g of methylenebisacrylamide in 240 ml of deionized water were mixed homogeneously at room temperature. The reaction mixture was subsequently maintained at 80 ° C for 6 hours without stirring, and a solid gel was obtained. c) The two gels are each mechanically pulverized, and the pulverized gels are mixed with each other in a ratio of 1: 1, based on the solid contents of the gels, grinding of repeated joint meat. The mixed gel was dried at 80 to 100 ° C in a vacuum drying cabinet, milled and graded at 106-850 μm.

The product has the following properties: PUP 0.014 psi = 55.2 g / g after 240 min PUP 0.7 psi = 51.4 g / g after 240 min PUP 1.4 psi = 41.7 g / g after 240 min CRC = 20.7 g / g SFC = 1055 x 107 cpr g SFC SFC index (0.3 psi) = 1055 x 10"7 cm3 s / g SFC (0.6 psi) = 315 x 10" 7 cm3 s / g SFC (0.8 psi) = 47 x 10"7 cm3 s / g SFC index = 378745 PAI (NaCl) AUL 0.01 psi 43.8 g / g after 240 min AUL 0.29 psi 41.6 g / g after 240 min AUL 0.57 psi 37.9 g / g after 240 min AUL 0.90 psi 34.9 g / g after 240 min PAI 158.2 AUL 0.01 psi 50.3 g / g after 16 hours AUL 0.2-9 psi 47.8 g / g after 16 hours AUL 0.57 psi 44.2 g / g after 16 hours AUL 0.90 psi = 40.7 g / g after 16 hours PAI = 183.0 PAI (Jayco) AUL 0.01 psi = 63.6 g / g after 240 min AUL 0.29 psi = 58.1 g / g after 240 min AUL 0.57 psi = 55.3 g / g after 240 min AUL 0.90 psi = 52.9 g / g after 240 min PAI = 229.9 AUL 0.01 psi = 70.4 g / g after 16 hours AUL 0.29 psi = 64.8 g / g after 16 hours AUL 0.57 psi = 61.9 g / g after 16 hours AU1 0.90 psi = 58.3 g / g after 16 hours PAI = 255.4 Diffusion of. Absorbency Under Pressure = 51.6 g / g Purge Performance: Purge Distance = 11 cm Purge Capacity = 13.1 g Acquisition / Rewet Time under Pressure: Acquisition Time 1 = 38 s Acquisition Time 2 = 32 s Acquisition Time 3 = 13 s Rewet 1 < 0.1 g Rewet 2 < 0.1 g Rewet 3 < 1.4 g Factor RAC = 101 DATGLAP = 86.2 g / g Preparation of polymer I of post-crosslinked surface Base A Polymer Gel 8.0 kg of acrylic glacial acid was diluted with 24 kg of water in a 40 liter plastic bucket. 37 g (0.457% by weight, based on acrylic acid) of pentaerythritol triallyl ether were added with stirring, and the sealed bucket was inactivated by adding 4 g of 2,2'-azobisamidinopropane dihydrochloride, dissolved in 100 ml of water, 460 mg of hydrogen peroxide and 170 mg of ascorbic acid, each also dissolved in 100 ml of water. Approximately 3 hours after the reaction was finished, the gel was mechanically sprayed.

Polymer A0 The polymeric base gel was dried at 50 ° C in a cabinet dried under reduced pressure, ground in a coffee mill and finally rated at 100-800 μm.

Polymer Al Polymer A0 was placed in a laboratory Waring blender and sprayed with crosslinked solution of the following composition: 2.5 wt% of 1,2-propanediol, 2.5 wt% of water, 0.2 wt% of ethylene glycol diglycidyl ether, based on polymer used. The wet product was subsequently tempered at 120 ° C in a circulating drying cabinet for 120 minutes. The dried product was sieved at 850 μm to remove agglutination.

Polymer A2 The base polymer gel A was mixed with sufficient caustic soda to obtain a neutralization of 10 mol%, based on the acrylic acid used. The partially neutralized gel is then dried, ground, sieved and similarly post-cross-linked to Al.

Polymer A3 The base polymer gel A was mixed with sufficient caustic soda to obtain a neutralization of 20 mol%, based on the acrylic acid used. The partially neutralized gel is then dried, milled, sieved and similarly post-crosslinked to the Al polymer.

Polymer A4 The base polymer gel A was mixed with sufficient caustic soda to obtain a neutralization of 30 mol%, based on the acrylic acid used. The partially neutralized gel is then dried, milled, sieved and similarly post-crosslinked to the Al polymer.

Polymer A5 The base polymer gel A was mixed with sufficient caustic soda to obtain a neutralization of 40 mol%, based on the acrylic acid used. The partially neutralized gel is then dried, milled, sieved and similarly post-lattice to the Al polymer.

Polymer A6 The base polymer gel A was mixed with sufficient caustic soda to obtain a neutralization of 40 mol%, based on the acrylic acid used. The partially neutralized gel is then dried in a drum dryer, milled in a pin mill and rated at 100-800 μm. The post-cross-linking takes place in a Lodige mixer by spraying a cross-linked solution of the following composition: 4% by weight of methanol, 6% by weight of water, 0.2% by weight of 2-oxazolidonone, based on the polymer powder used, in 1 kg of polymer powder through a nozzle of two materials. The wet product was subsequently warmed to 180 ° C in a drying cabinet through circulation for 90 minutes. The dried product was sieved at 850 μm to remove binders.

Polymer A7 The base polymer gel A was neutralized, dried and ground similarly to polymer A6. The powder is then sprayed with a crosslinked solution in a Waring laboratory mixer. The solution has such a composition that the following dosage is obtained based on the base polymer used: 0.30% by weight of 2-oxotetrahydro-l, 3-oxazine, 3% by weight of 1,2-propanediol, 7% by weight of water and 0.2% by weight of boric acid. The wet polymer is then dried at 175 ° C for 60 minutes.

Polymer A8 1040 g of acrylic glacial acid were diluted with 2827 g of completely iron-free water in a polymerization flask 5 1. 5.2 g of allyl methacrylate was added to this solution with stirring, and the sealed flask was inactivated by passing nitrogen to through him. The polymerization was then started by adding 0.52 g of 2,2'-azobisamidinopropane dihydrochloride, dissolved in 25 ml of completely iron-free water, 165 mg of 35% by weight of hydrogen peroxide, dissolved in 12 g of completely free water. of iron, and 20.8 mg of ascorbic acid, dissolved in 15 ml of water completely free of iron. Approximately 3 hours after the reaction ended, the gel is mechanically pulverized, dried at 50 ° C in a drying cabinet under reduced pressure, ground in a coffee mill and finally rated at 150-800 μm. The polymer thus obtained was placed in a Waring laboratory mixer and sprayed with crosslinked solution of the following composition: 2.5 wt% of 1,2-propanediol, 2.5 wt% of water, 0.2 wt% of ethylene glycol diglycidyl ether, based in the polymer used. The wet product was then tempered at 120 ° C through a dry circulation cabinet for 120 minutes. The dry product was sieved 850 μm to remove binders. Preparation of post-crosslinked surface polymer II Polymer Bl 4.1 g of ethylene glycol diglycidyl ether were stirred at room temperature in 2123 g of 5.5% by weight of salt-free polyvinylamine solution (K 137) until homogenous, and the solution was warmed overnight at 60 ° C. The resulting gel was mechanically pulverized, dried at 80 ° C under reduced pressure, milled and rated at 150-800 μm. This polymer was placed in a Waring laboratory mixer and sprayed with crosslinked solution having such a composition that the following dosage was obtained based on the base polymer used: 0.20% by weight of ethylene glycol diglycidyl ether, 2.5% by weight of 1, 2- Propandiol and 2.5% by weight of water. The wet polymer was then dried at 120 ° C for 60 minutes.

Base Polymer B 621 g of a commercially available polyethyleneimine (POLYMIN® P, Brookfield viscosity at 20 ° C, approximately 22,000 mPas) were stirred with 279 g of distilled water to form a homogeneous solution. 6.0 g of ethylene glycol diglycidyl ether, dissolved in 100 g of distilled water, stirred at room temperature and homogenized. The mixture was subsequently heated in a covered form at 80 ° C for 6 hours. The resulting gel was mechanically pulverized subsequently, dried at 80 ° C under reduced pressure, milled and rated at 150-850 μm.

Polymer B2 The Base B polymer was placed in a Waring laboratory mixer and sprayed with crosslinked solution of the following composition: 2.5 wt.% Of 1,2-propanediol, 2.5 wt.% Of water, 0.2 wt.% Of ethylene glycol diglycidyl ether, based on the polymer used. The wet product was subsequently warmed to 120 ° C in a vacuum drying cabinet for 120 minutes. The dried product was sieved at 850 μm to remove binders.

Polymer B3 The Base B polymer was placed in a Waring laboratory mixer and sprayed with crosslinked solution. The solution has such a composition that the following dosage was obtained based on a base polymer used: 0.20% by weight of glutaraldehyde, 3.0% by weight of 1,2-propandiol and 2.0% by weight of water. The wet polymer was then dried at 120 ° C for 60 minutes and sieved at 850 μm.

Polymer B4 The Base B polymer was placed in a Waring laboratory mixer and sprayed with crosslinked solution. The solution has such a composition that the following dosage was obtained in the base polymer used: 0.5% by weight of polyamidoamine resin (Resanan® VHW 3608 from Hoechst AG), 2% by weight of 1,2-propandiol and 3% by weight of water. The wet polymer is then dried at 120 ° C for 60 minutes and sieved at 850 μm.

Polymer B5 The Base B polymer was placed in a Waring laboratory mixer and sprayed with crosslinked solution. The solution has such a composition that the following dosage was obtained based on the base polymer used: 0.2% by weight of 2-oxazolidinone, 3.0% by weight of 1,2-propanediol and 2.0% by weight of water. The wet polymer was then dried at 180 ° C for 60 minutes and sieved at 850 μm. The polymers prepared according to the above Examples were tested individually, and the results were subsequently summarized in Table 1: Table 1: Table 1: Examples 8.1 to 8.16 Post-crosslinked surface polymers A and B were used to create homogenous mixtures. The polymers used in each case, their mixing ratios and the application measures of the mixtures are shown in Table 2.

Post-crosslinked surface of base polymer powder mixtures of polymers I and II.

Examples 9.1 - 9.3 The polymer powders prepared according to the Examples AO to A8, but without post-crosslinked surface were homogeneously mixed with polymeric powders prepared according to Examples B and Bl (without the post-crosslinked surface described herein) and sprayed with cross-linked solution (2.5 wt% of 1 , 2-propanediol, 0.2% by weight of ethylene glycol diglycidyl ether and 2.5% by weight of water) in a laboratory Waring blender and then dried at 120 ° C for 60 minutes. The polymeric types used, mixing ratios and test results are summarized below in Table 3. Table 2: Table 2: Performance data of powder mixtures of each polymer I and II previously post-crosslinked OD or Table 3: Post-crosslinking surface of polymer-based polymer powder mixes I and II Example 10 100 g of polyethylene glycol-based graft copolymer of average molar mass 9000 (70 g) and N-vinylformamide (30 g) and having a K value of 42 with 900 g of demineralized water were diluted and stirred with 20 g of 40% by weight sodium bisulfite solution and 67 g of 25% by weight aqueous sodium hydroxide solution at 80 ° C. An additional NaOH solution of 20.1 g of 25% by weight was added for 24 hours. The degree of hydrolysis was 81.4% of the theory determined at pH 3.5 by polyelectrolyte titration. This polymer solution was desalted by ultrafiltration using a membrane (exclusion limit 3000 D). 200 g of immensely desalted polymer solution (non-volatile 5%) were mixed with 0.2 g of acrylic acid and crosslinked at 175 ° C in a Teflon-coated pan in a vacuum drying cabinet for 10 minutes. The polymer thus obtained was dried and ground easily. A 1: 1 powder mixture of this polymer and a crosslinked polyacrylic acid (base polymer A0) were tested for their application properties. Absorption capacity (30 min) [g / g]: 32.7 Absorption capacity (4 hours) [g / g]: 46.3 CRC (30 minutes) [g / g]: 19.2 .AAP (0.7 psi) [g / g ]: 17.0 Example 11 50 g of a high molecular weight polyethylene imine (average 500,000 molar mass) having a solids content of 49.5% by weight were mixed with 100 parts of an acrylamide copolymer (98 g) and hydroxyethyl acrylate ( 2 g) K 72.1 and a solids content of 14.8% by weight and kneaded for 1 hour in a laboratory kneader Jahnke & Kunkel The gel was dried at 70 ° C under reduced pressure for 24 hours and subsequently ground. A 1: 1 powder mixture of this polymer and crosslinked polyacrylic acid (according to Example la) were tested for their absorption properties. Absorption capacity (30 min) [g / g]: 26.5 CRC (30 minutes) [g / g]: 10.4 AAP (0.3 psi) [g / g]: 17.6 Example 12 600 g of a completely iron-free polyvinylamine homopolymer having a K-value of 91, a degree of hydrolysis of 90.1% and a solids content of 4% by weight were mixed with 1 g of acrylic acid in a kneader laboratory and reticulated at 100 ° C. An additional 600 g of polyvinylamine was added during this period and a total of 490 g of water were distilled. After 5 hours the polymer was insoluble to water. The gel was then dried at 75 ° C under reduced pressure for 24 hours and subsequently ground. A 1: 1 powder mixture of this polymer and a crosslinked polyacrylic acid (base polymer AO) was tested. Absorptive capacity (30 min) [g / g]: 30.3 CRC (30 minutes) [g / g]: 15.1 CRC (4 hours) [g / g]: 23.3 Absorption capacity (4h) [g / g]: 42.0 AAP (0.7 psi) [g / g]: 16.2 PUP (0.7 psi Jayco) [g / g]: 15.3 PUP (0.7 psi Jayco, 4 h) [g / g]: 22.3 Example 13 500 g of a completely iron-free polyvinylamine homopolymer having a K value of 85, a degree of hydrolysis of 92.1% and a solids content of 6.7% by weight were mixed with 1 g of methyl acrylate in a kneader and reticulated at 100 ° C. An additional 500 g of polyvinylamine was added during this period and a total of 360 g of water were distilled. After 5 hours the polymer was insoluble to water. The gel was then dried at 75 ° C under reduced pressure for 24 hours and subsequently ground. A 1: 1 powder mixture of this polymer and a crosslinked polyacrylic acid (base polymer A0) were tested for use as superabsorbents. Absorptive capacity (30 min) [g / g]: 28.7 CRC (30 min) [g / g]: 17.9 AAP (0.3 psi) [g / g]: 15.3 Example 14 200 g of a completely iron-free polyvinylamine homopolymer solution (5% nonvolatile) was mixed with 0.4 g of urea and crosslinked at 175 ° C in a Teflon-coated pan in a vacuum drying cabinet for 10 hours. minutes The polymer obtained was broken and dried after an additional drying step at 185 ° C and easily ground. A 1: 1 powder mixture of this polymer and a crosslinked polyacrylic acid of Example la) were tested. Absorptive capacity (30 min) [g / g]: 24.9 CRC (30 min) = [g / g]: 10.1 Absorption capacity (4h) [g / g]: 41.9 CRC (4 h) [g / g] : 16.5 AAP (0.7 psi lh) [g / g]: 15.6 Example 15 200 g of a completely ion free (nonvolatile 5%) polyvinylamine homopolymer solution was mixed with 0.4 g of propylene carbonate and crosslinked at 175 ° C in a Teflon-coated pan in a vacuum drying cabinet for 10 minutes. The polymer obtained was broken and dried after an additional drying step at 185 ° C and easily ground. A 1: 1 powder mixture of this polymer and a crosslinked polyacrylic acid of Example la) were tested for use as superabsorbents. Absorptive capacity (30 min) [g / g]: 25.0 CRC (30 min) [g / g]: 10.6 Absorption capacity (4h) [g / g]: 40.6 CRC (4 h) [g / g] 16.8 .AAP (0.7 psi lh) [g / g]: 16.4 Example 16 668.9 g of a K 137 desalted polyvinylamine (non-volatile 2.8%) were self-crosslinked at 185 ° C in a Teflon-coated pan in a vacuum drying cabinet for 2 hours. The resulting product can be peeled off as a film. This gives approximately 20 g of the solid polymer which was milled in an analytical mill. A 1: 1 powder mixture of this polymer and a crosslinked polyacrylic acid (according to Example la) was tested for its absorption properties. Absorption capacity (30 min) [g / g]. 8.5 Absorption capacity (4 h) [g / g]: 64.3 CRC (30 min) [g / g]: 25.4 .AAP (0. 7 psi lh) [g / g]: 16. Example 17 337.3 g of a K 137 desalted polyvinylamine (non-volatile 2.5%) were mixed for 45 minutes in a laboratory kneader Jahnke & Kunkel with 33.37 g of a polyacrylic acid gel of 25% by weight according to Example la (ratio of solids content 1: 1) at room temperature. This is followed by crosslinking at 180 ° C under nitrogen in a pan coated with Teflon in a vacuum drying cabinet at 400 mbar for 1.5 hours. The product was milled in an analytical mill and subsequently screened through a 500 μ sieve. The absorbent properties of this solid polymer were: Absorption capacity (30 min) [g / g]: 35.1 Absorption capacity (4 h) [g / g]: 43.9 CRC (30 min) [g / g]: 11.8 AAP (0.7 psi lh) [g / g]: 23.8 Example 18 200 g of a desalted polyvinylamine (non-volatile 2.5%) were mixed at room temperature in a Duplex kneader with 30 g of a 25% polyacrylic acid gel according to Example la at room temperature (solids content ratio of polyvinylamine to superabsorbent 4: 6) for 1 hour and subsequently crosslinked in a pan coated with Teflon at 400 mbar under nitrogen at 180 ° C for 1.5 hours.

The product was milled in an analytical mill and subsequently screened through a 500 μ sieve. The absorbent properties of this solid polymer were: absorption capacity (30 min) [g / g]: 30.6 absorption capacity (4 h) [g / g]: 38.4 CRC (30 min) [g / g]: 11.2 AAP (0.7 psi) [g / g]: 21.6

Claims (22)

1. CLAIMS 1. A hydrogel-forming polymer mixture includes a) a hydrogel I that forms hydrogel containing acid radicals and b) a hydrogel forming polymer II that contains amino and / or imino radicals that have been made insoluble in water by crosslinking, in wherein the ratio of such acid radicals to the sum total of such amino / imino radicals is within the range of 1: 9 to 9: 1 and such polymer mixture has a SFC index of > 10,000 obtained from three SFC measurements under different pressures according to the formula SFC = [SFC (0.3 psi) • 107 g / cm3s] • ([SFC (0.6 psi) - 107 g / cm3s] + [SFC (0.9 psi) • 107 g / cm3s]).
2. 2. The hydrogel-forming polymer mixture as recited in claim 1, wherein such a hydrogel-forming polymer I is cross-linked polyacrylic acid wherein from 0 to 50% of the carboxyl groups are present as the alkali metal and / or salt of the hydrogel. ammonium.
3. 3. The hydrogel-forming polymer mixture as recited in claim 1 or 2, wherein such hydrogel-forming polymer II is cross-linked and is a polyethyleneimine, a grafted ethyleneimine polyamidoamine, and / or ethylene imine grafted polyamine.
4. 4. The hydrogel-forming polymer mixture as claimed in claim 1 or 2, wherein such hydrogel-forming polymer II is a crosslinked polyvinylamine.
5. 5. The hydrogel-forming polymer mixture as recited in claim 4, wherein the hydrogel-forming polymer II is obtained by hydrolysis of polyvinylformamide having a degree of hydrolysis of 70-100% and subsequent thermal crosslinking.
6. 6. The hydrogel-forming polymer mixture as recited in claim 1 or 2, wherein such a hydrogel-forming polymer II is obtained by copolymerization of vinylformamide and one or more monoethylenically unsaturated compounds, subsequent hydrolysis with or without desalting and subsequent cross-linking. .
7. The hydrogel-forming polymer mixture as recited in claim 1 or 2, wherein such a hydrogel-forming polymer II is a vinylformamide graft copolymer in polymeric compounds which is subsequently subjected to hydrolysis with or without desalination and cross-linking .
8. 8. The hydrogel-forming polymer mixture, as claimed in any of claims 1, 2 and 6, wherein such hydrogel-forming polymer II is a copolymer of vinylformamide and mono- and / or polycarboxylic monoethylenically unsaturated acid, the which is subsequently subjected to hydrolysis with or without desalting and crosslinking by heating.
9. 9. The hydrogel-forming polymer mixture as recited in any of claims 1, 2 and 6, wherein such a hydrogel-forming polymer II is a copolymer of vinylformamide and mono- and / or polycarboxylic monoethylenically unsaturated acid, which is subject to hydrolysis with or without desalting and crosslinking by heating and subsequently to further crosslinking with a cationic polymer or copolymer based on polyvinylamine or polyethyleneimine and / or with at least one bifunctional crosslinker.
10. The hydrogel-forming polymer blend as claimed in any of claims 1 to 3, wherein such a polymer II is a polyethyleneimine, an ethyleneimine grafted polyamidoamine or a similarly modified polymer polyamine by reacting with α, β-unsaturated carboxylic acids or esters or by Strecker reaction and subsequently thermally crosslinked.
11. 11. The hydrogel-forming polymer mixture as claimed in claim 1, having a PAI (NaCl) index of > 100 after a dilated time of 16 hours.
12. 12. The hydrogel-forming polymer blend as claimed in claim 1, which has a PAI (Jayco) index of > 150 after a dilated time of 16 hours.
13. 13. The hydrogel-forming polymer mixture as claimed in claim 1, which has a Diffusion of Absorbency Under Pressure of > 30 g / g.
14. 14. The hydrogel-forming polymer mixture as claimed in claim 1, which has a distance of Purge > 5 in the Purge Performance Test and a Purge Capacity of at least 5 g.
15. 15. The hydrogel-forming polymer mixture as claimed in claim 1, having an Acquisition Time 3 of < 25 s and a Rewet 3 of no more than 9 g in the Acquisition Time / Rewet Test under pressure.
16. 16. The hydrogel-forming polymer mixture as recited in claim 1, having a RAC Factor of at least 80.
17. 17. The hydrogel-forming polymer mixture as claimed in claim 1, having a DATGLAP of at least 50 g / g.
18. 18. The hydrogel-forming polymer mixture as claimed in claim 1, obtained by mixing polymer gel I and polymer powder II or by mixing polymer powder I and polymer gel II.
19. 19. The hydrogel-forming polymer mixture as claimed in claim 1, obtained by the addition of a component I or II mixed as a powder to the reaction mixture of the other component.
20. 20. The mixture of hydrogel-forming polymer as claimed in claim 1, obtained by self-crosslinking of polyvinylamine obtainable by hydrolysis of amide in the form of polyvinyl having a degree of hydrolysis of 70-100% in the drying of a mixture of such polymers I and II at 80-200 ° C.
21. 21. The method for using the hydrogel-forming polymer blend of claim 1, as an absorbent for water and aqueous fluids.
22. 22. The method for using the hydrogel-forming polymer blend of claim 1, in sanitary articles used to absorb body fluids.