Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J3/00—Processes of treating or compounding macromolecular substances
  • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
  • C08J3/246—Intercrosslinking of at least two polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
  • C08L101/12—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity
  • C08L101/14—Compositions of unspecified macromolecular compounds characterised by physical features, e.g. anisotropy, viscosity or electrical conductivity the macromolecular compounds being water soluble or water swellable, e.g. aqueous gels
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2300/00—Characterised by the use of unspecified polymers
  • C08J2300/14—Water soluble or water swellable polymers, e.g. aqueous gels

Definitions

• the present invention relates to hydrogel-forming polymer mixtures containing
• Superabsorbents often have satisfactory results in terms of their absorption capacity for deionized water, but they decrease when exchanged for body fluids such as urine. This effect of the quasi "poisoning" of the super absorber is generally attributed to the salinity of the body fluids.
• WO 96/15162, WO 96/15163, WO 96/17681 and WO 98/37149 propose a superabsorbent material which is composed of an anionic and a cationic superabsorbent material, the cationic superabsorbent material being polymer units which are quaternary amine functions and are due to bisallylbisalkylammonium ions.
• EP-A-0210756 teaches an absorbent mixture of a cation and an anion exchange material, which is a modified cellulose fiber in both cases.
• the object of the present invention was to provide a new hydrogel-forming polymer mixture which has good absorption properties, good distribution properties and high mechanical stability.
• Hydrogel-forming polymers I are water-insoluble polymers with free acid groups.
• Crosslinked polyacids in particular polycarboxylic acids, which can partly be present as a salt, are preferred.
• Polymers I which are prepared by crosslinking polymerization or copolymerization of monoethylenically unsaturated monomers bearing acid groups are preferred. It is also possible to (co) polymerize the monoethylenically unsaturated monomers bearing acid groups without crosslinking agents and to subsequently crosslink them.
• Such monomers bearing acid groups are, for example, monoethylenically unsaturated C 3 -C 25 -carboxylic acids or anhydrides such as acrylic acid, methacrylic acid, ethacrylic acid, ⁇ -chloroacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid and fumaric acid.
• monoethylenically unsaturated C 3 -C 25 -carboxylic acids or anhydrides such as acrylic acid, methacrylic acid, ethacrylic acid, ⁇ -chloroacrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, citraconic acid, mesaconic acid, glutaconic acid, aconitic acid and fumaric acid.
• monoethylenically unsaturated sulfonic or phosphonic acids for example vinylsulfonic acid, allylsulfonic acid, sulfoethyl acrylate, sulfoethyl methacrylate, sulfo- fopropyl acrylate, sulfopropyl methacrylate, 2-hydroxy-3-acryloxypropylsulfonic acid, 2-hydroxy-3-methacryloxypropylsulfonic acid, vinylphosphonic acid, allylphosphonic acid, styrene sulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid.
• the monomers can be used alone or as a mixture with one another.
• Preferred monomers are acrylic acid, methacrylic acid, vinylsulfonic acid, acrylamidopropanesulfonic acid or mixtures of these acids, e.g. Mixtures of acrylic acid and methacrylic acid, mixtures of acrylic acid and acrylamidopropanesulfonic acid or mixtures of acrylic acid and vinylsulfonic acid.
• additional monoethylenically unsaturated compounds which do not have an acid group but can be copolymerized with the monomers bearing acid groups.
• monoethylenically unsaturated compounds include, for example, the amides and nitriles of monoethylenically unsaturated carboxylic acids, for example acrylamide, methacrylamide and N-vinylformamide, N-vinyl acetamide, N-methyl-N-vinyl acetamide, acrylonitrile and methacrylonitrile.
• Suitable compounds are, for example, vinyl esters of saturated C ⁇ ⁇ to C -carboxylic acids such as vinyl formia, vinyl acetate or vinyl propionate, alkyl vinyl ether with at least 2 C atoms in the alkyl group, such as ethyl vinyl ether or butyl vinyl ether, esters of monoethylenically unsaturated C 3 - to C 6 -carboxylic acids , for example esters from monohydric C ⁇ ⁇ to cis alcohols and acrylic acid, methacrylic acid or maleic acid, half esters of maleic acid, for example monomethyl maleate, N-vinyl lactams such as N-vinylpyrrolidone or N-vinylcaprolactam, acrylic acid and methacrylic acid esters of alkoxylated monohydric, saturated alcohols, for example from Alcohols with 10 to 25 carbon atoms which have been reacted with 2 to 200 moles of ethylene oxide and / or propylene oxide per mole
• Compounds which have at least 2 ethylenically unsaturated double bonds can function as crosslinkers.
• Examples of compounds of this type are N, N '-methylene-bisacrylamide, poly- ethylene glycol diacrylates and polyethylene glycol dimethacrylates, which are each derived from polyethylene glycols with a molecular weight of 106 to 8500, preferably 400 to 2000, trimethylol propane triacrylate, trimethylol propane trimethacrylate, ethylene glycol diacrylate, propylene glycol diacrylate, hexane diol acrylate, allyl diol acrylate, butane diol diacrylate, allyl diacrylate, acrylate, butane diol diol acrylate, butane diol diol acrylate, block diol acrylate from ethylene oxide and propylene oxide, double or triple esterified with acrylic acid or methacrylic acid, polyhydric alcohols, such as glycerol or pen
• Water-soluble crosslinking agents are preferably used, for example N, N '-methylene-bisacrylamide, polyethylene glycol diacrylates and polyethylene glycol dimethacrylates which are derived from addition products of 2 to 400 mol of ethylene oxide to 1 mol of a diol or polyol, vinyl ethers of addition products of 2 to 400 mol Ethylene oxide on 1 mole of a diol or polyol, ethylene glycol diacrylate, ethylene glycol dimethacrylate or triacrylates and trimethacrylates of addition products of 6 to 20 moles of ethylene oxide on 1 mole of glycerol, pentaerythritol triallyl ether and / or divinyl urea.
• N, N '-methylene-bisacrylamide polyethylene glycol diacrylates and polyethylene glycol dimethacrylates which are derived from addition products of 2 to 400 mol of ethylene oxide to 1 mol of a diol or polyol, vinyl ethers of addition
• crosslinkers are compounds which contain at least one polymerizable ethylenically unsaturated group and at least one further functional group.
• the functional group of these crosslinkers must be able to react with the functional groups, essentially the acid groups of the monomers. Suitable functional groups are, for example, hydroxyl, amino, epoxy and aziridino groups.
• hydroxyalkyl esters of the abovementioned monoethylenically unsaturated carboxylic acids for example 2-hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxybutyl acrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate and hydroxylbutyl methacrylate, dialkyldiallylammonium halide, such as dimethyldimidylchloride, such as dimethyldimidium chloride, N-vinylimidazole, l-vinyl-2-methylimidazole and N-vinylimidazolines such as N-vinylimidazoline, l-vinyl-2-methylimidazoline, l-vinyl-2-ethylimidazoline or l-vinyl-2-propylimidazoline, which are in the form of free bases, in quaternized form or as a salt can be used in the polymerization
• Dialkylaminoalkyl acrylates and dialkylaminoalkyl methacrylates dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate and diethylaminoethyl methacrylate are also suitable.
• the basic esters will preferably used in quaternized form or as a salt.
• glycidyl (meth) acrylate can also be used, for example.
• the crosslinkers are present in the reaction mixture, for example from 0.001 to 20% by weight and preferably from 0.01 to 14% by weight.
• the polymerization is initiated as usual by an initiator. All initiators which form free radicals under the polymerization conditions and are usually used in the production of superabsorbers can be used as initiators for initiating the polymerization. Also one
• aqueous mixture is possible.
• the polymerization can also be initiated in the absence of initiators of the type mentioned above by exposure to high-energy radiation in the presence of photoinitiators.
• All compounds which decompose into free radicals under the polymerization conditions can be used as polymerization initiators, for example peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and the so-called redox catalysts.
• the use of water-soluble initiators is preferred.
• mixtures of different polymerization initiators for example mixtures of hydrogen peroxide and sodium or potassium peroxodisulfate.
• Suitable organic peroxides are, for example, acetylacetone peroxide, methyl ethyl ketone peroxide, tert. -Butyl hydroperoxide, cumene hydroperoxide, tert-amyl perpivalate, tert. Butyl perpivalate, tert. Butyl perneohexanoate, tert. -Butylperisobutyra, tert. -Butyl-per-2-ethylhexanoate, tert. - Butyl perisononanoate, tert.
• Particularly suitable polymerization initiators are water-soluble azo starters, for example 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N 'dimethyl) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutyronitrile, 2,2'-azobis [2- (2 '-imidazolin-2-yl) propane] dihydrochloride and 4,4'-azobis (4-cyanovaleric acid).
• the polymerization initiators mentioned are used in customary amounts, for example in amounts of 0.01 to 5, preferably 0.1 to 2.0% by weight, based on the monomers to be polymerized.
• Redox catalysts are also suitable as initiators.
• the redox catalysts contain at least one of the above-mentioned per compounds as the oxidizing component and, for example, ascorbic acid, glucose, sorbose, ammonium or alkali metal hydrogensulfite, sulfite, thiosulfate, hyposulfite, pyrosulfite or sulfide, metal salts as the reducing component , such as iron (II) ions or silver ions or sodium hydroxymethylsulfoxy- lat.
• Ascorbic acid or sodium sulfite is preferably used as the reducing component of the redox catalyst. Based on the amount of monomers used in the polymerization, for example 3-10 -6 to 1 mol% of the reducing component of the redox catalyst system and 0.001 to 5.0 mol% of the oxidizing component of the redox catalyst are used.
• Triggers radiation so-called photoinitiators are usually used as initiators. These can be, for example, so-called ⁇ -splitters, H-abstracting systems or also azides.
• initiators are benzophenone derivatives such as Michler's ketone, phenanthrene derivatives, fluorene derivatives, anthraquinone derivatives, thioxanone derivatives, coumarin derivatives, benzoin ethers and their derivatives, azo compounds such as the radical formers mentioned above, substituted hexaaryl bisimidazoles or Acylphosphine oxides.
• azides examples include: 2- (N, -dimethylamino) -ethyl-4-azidocinnamate, 2- (N, -dimethylamino) -ethyl-4-azidonaphthyl ketone, 2- (N, N-dimethylamino) -ethyl -4-azidobenzoate, 5-azido-l-naphthyl-2 '- (N, N-dimethylamino) ethylsulfone, N- (4-sulfonyl azidophenyldmaleinimide, N-acetyl-4-sulfonyl azidoaniline, 4-sulfonyl azidoaniline, 4- Azidoaniline, 4-azidophenacyl bromide, p-azide-topzoic acid, 2, 6-bis (p-azidobenzylidene) cyclohexanone and
• the photoinitiators are usually used in amounts of 0.01 to 5% by weight, based on the monomers to be polymerized.
• polyacids which have been prepared by the polymerization of the abovementioned monoethylenically unsaturated acids and, if appropriate, monoethylenically unsaturated comonomers and which have a molecular weight greater than 5000, preferably greater than 50,000, are reacted with compounds which have at least two groups which are reactive towards acid groups exhibit. This reaction can take place at room temperature or at elevated temperatures up to 200 ° C.
• the suitable functional groups have already been mentioned above, ie hydroxyl, amino, epoxy, isocyanate, ester, amido and aziridino groups.
• crosslinking agents examples include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, glycerin, polyglycerol, propylene glycol, polypropylene glycol, block copolymers from ethylene oxide and propylene oxide, sorbitan fatty acid ester, ethoxylated sorbitan fatty acid ester, 3-trimethylol propane, pentaerythritol , 1,4-butanediol, polyvinyl alcohol, sorbitol, polyglycidyl ethers such as ethylene glycol, polyethylene glycol diglycidyl ether, glycerol diglycidyl ether, glycerol polyglycidyl ether, Diglycerinpo- lyglycidylether, polyglycerol polyglycidyl ether, Sorbitpolyglyci- dylether, pentaerythritol polyg
• crosslinkers for postcrosslinking are polyvalent metal ions, which are able to form ionic crosslinks.
• 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 crosslinkers are multifunctional bases which are also able to form ionic crosslinks, for example polyamines or their quaternized salts.
• polyamines are ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, pentaethylene hexamine and polyethylene imines as well as polyvinyl amines with molecular weights of up to 4,000,000 each.
• crosslinking agents are added to the polyacrylic acid or the polyacrylic acid salts in amounts of 0.5 to 25% by weight, preferably 1 to 15% by weight, based on the amount of the polyacids used.
• the crosslinked polyacids are used in the invention
• Polymer mixture preferably used unneutralized. Nevertheless, it can be advantageous to partially re-acidify the acid functions. tralize.
• the degree of neutralization will be essentially less than 50%, preferably less than 30%. Possible neutralizing agents are:
• Alkali metal bases or ammonia or amines Sodium hydroxide solution or potassium hydroxide solution is preferably used.
• the neutralization can also be carried out using sodium carbonate, sodium hydrogen carbonate, potassium carbonate or potassium hydrogen carbonate or other carbonates or hydrogen carbonates or ammonia.
• prim. , sec. and tert. Amines can be used.
• aqueous solution Polymerization in aqueous solution is preferred as so-called gel polymerization. 10 to 70% by weight aqueous solutions of the monomers and, if appropriate, a suitable graft base are polymerized in the presence of a radical initiator using the Trommsdorff-Norrish effect.
• the polymerization reaction can be carried out in the temperature range between 0 and 150.degree. C., preferably between 10 and 100.degree. C., both under normal pressure and under elevated or reduced pressure.
• the polymerization can also be carried out in a protective gas atmosphere, preferably under nitrogen.
• the quality properties of the polymers can be improved further by reheating the polymer gels for several hours in the temperature range from 50 to 130 ° C., preferably from 70 to 100 ° C.
• Suitable polymers I are also graft (co) polymers of one or more hydrophilic monomers on a suitable graft base, crosslinked cellulose or starch ethers and esters containing acid groups, crosslinked carboxymethyl cellulose, or natural products with acid groups which are swellable in aqueous liquids, such as, for example Alginates and carrageenans.
• Suitable graft bases can be of natural or synthetic origin. Examples are starch, cellulose or cellulose derivatives and other polysaccharides and oligosaccharides, polyvinyl alcohol, polyalkylene oxides, in particular polyethylene oxides and Polypropylene oxides, polyamines, polyamides and hydrophilic polyesters. Suitable polyalkylene oxides have, for example, the formula
• R 1 and R 2 independently of one another are hydrogen, alkyl, alkenyl or acrylic,
• X is hydrogen or methyl and n is an integer from 1 to 10,000.
• R 1 and R 2 are preferably hydrogen, (-C ⁇ C 4 ) alkyl, (C -C 6 ) alkenyl or phenyl.
• Polymer II is to be understood as an amino radical according to the IUPAC rules, primary amino groups and not amido groups in which the NH radical is linked to a carbonyl radical. Accordingly, imino residue according to the IUPAC rules are to be understood as secondary amino groups (-NH-) and not imido groups in which the NHR residue is linked to a carbonyl residue.
• Suitable hydrogel-forming polymers II are the following polymers bearing amino and / or imino residues which have been rendered water-insoluble by crosslinking.
• Preferred polymers are polymers, copolymers and graft copolymers of "vinylamine” or ethyleneimine, which can be modified in a polymer-analogous manner.
• polyvinylamines i.e. polymers with the grouping -CH -CH (NH 2 ) - as a characteristic building block
• polymer-analogous reactions those skilled in the art are, for example, the hydrolysis of poly-N-vinyl amides such as poly-N-vinyl formamide, poly-N-vinyl acetamide, of poly-N-vinyl imides such as poly-N-vinyl succinimide and poly-N-vinyl phthalimide and the Hofmann degradation of polyacrylamide when exposed to basic hypochlorite is known.
• Polyvinylamines are preferably prepared by polymerization of N-vinylformamide and subsequent polymer-analogous reaction in accordance with DE-A-3 128 478.
• the molecular weight of the uncrosslinked polyvinylamine corresponds to a K value (determined according to H. Fikentscher, 5% by weight aqueous NaCl solution at 25 ° C. containing 1% by weight polymer) of 30-250. 10
• the N-vinylformamide units of the polymers can be hydrolyzed by acidic, basic or enzymatic hydrolysis to give the corresponding polymers containing vinylamine units. If you e.g. completely hydrolyzed a homopolymer of N-vinylformamide, polyvinylamine is obtained.
• Basic hydrolysis is particularly preferred. In this way degrees of hydrolysis of e.g. 5 - 95% available. Particularly preferred are products with a degree of hydrolysis of 70 to 100 and very particularly completely hydrolyzed products, i.e. maximum 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.
• Crosslinked polyvinylamines are preferably used as Polymers II which have previously been desalted.
• Desalted here means that the salt content of low molecular weight salts (molecular weight ⁇ 500) is 8% by weight, based on the polymer.
• Desalination is carried out, for example, by means of a dialysis or ultrafiltration process with a membrane with a 3000 D exclusion limit. The degree of desalination can be checked using gel permeation chromatography (GPC). Desalination is advantageously carried out after the polymer-analogous reaction and before the crosslinking reaction.
• GPC gel permeation chromatography
• the desalted polymer solutions II are usually used in aqueous solution for crosslinking.
• the polymer content of an aqueous solution is usually 2 to 50% by weight.
• polar aprotic Lö ⁇ sungsstoffn such as dimethyl sulfoxide or N-methylpyrrolidone to crosslink even more concentrated polymer solutions.
• polymers II which are obtained by crosslinking polyvinylamine with a K value of 30-250, preferably 50-230, in particular 70-200. Since the crosslinking slows down and possibly runs incompletely in the case of the high molecular weight polyvinylamines, it is particularly preferred to crosslink polyvinylamines which, in the uncrosslinked state, have a K value of 70-180.
• copolymers of “vinylamine” are suitable, that is copolymers of, for example, vinylformamide and comonomers, which are converted into formal copolymers of vinylamine by the polymer-analogous reactions described above.
• vinylformamide copolymers of, for example, vinylformamide and comonomers, which are converted into formal copolymers of vinylamine by the polymer-analogous reactions described above.
• all monomers copolymerizable with vinylformamide are suitable as comonomers.
• the following monounsaturated monomers may be mentioned by way of example:
• DE-A-3 534 273 copolymers of N-vinylformamide with vinyl acetate, vinyl propionate, (C ⁇ ⁇ C) alkyl vinyl ether, methacrylic acid and acrylic acid esters, acrylonitrile and acrylamide and their homologues and vinyl pyrrolidone.
• the concentration of the N-vinylformamide can be 10-95 mol%, that of the comonomers 5-90 mol%.
• Graft polymers of alkylene oxide units and N-vinylformamide according to DE-A-1 951 5943, which were crosslinked after the hydrolysis, are also suitable as polymers II.
• Such graft polymers can be prepared by radical polymerization of N-vinylformamide in the presence of, for example, polyethylene glycols and subsequent basic saponification.
• graft bases are polyvinyl acetate and / or polyvinyl alcohol.
• N-vinylformamide can be grafted onto these polymers by radical polymerization and the polymer thus obtained is hydrolyzed, optionally desalted and then crosslinked to give polymer II.
• Copolymers of vinyl acetate, acrylic acid, methacrylic acid, acrylamide and acrylonitrile are also suitable graft bases for N-vinylformamide.
• mono-, oligo- and polysaccharides which have optionally been oxidatively, enzymatically or hydrolytically degraded, are advantageous graft bases for N-vinylformamide, the proportion by weight of which is 20 to 95% based on the total amount of monomer + graft base .
• These graft polymers are then converted into the free amines by hydrolysis, optionally desalted and finally crosslinked to give polymers II.
• the graft polymers are preferably formed with N-vinylformamide as the only monomer. However, it is possible to replace up to 50% by weight of the N-vinylformamide with the above-mentioned comonomers of the N-vinylformamide.
• polyvinylamines, their copolymers and graft copolymers can also be modified by further polymer-analogous reactions. These reactions are diverse and can be found in any textbook on organic chemistry such as "Advanced Organic Chemistry” by Jerry March, 3rd edition, John Willey & Sons 1985.
• Formic acid or formic acid orthoesters react vicinal amino groups of polyvinylamine to six-membered cyclic amidines, as described, for example, in US Pat. No. 5,401,808. It may well be that some of the amino groups have reacted with vicinal formamide groups to form cyclic amidine structures.
• polymer-analogous reactions of polyvinylamines a large number of other such reactions are possible. These include amidation, alkylation, sulfonamide formation, urea formation, thiourea formation, carbamate formation, acylation with acids, lactones, acid anhydrides and acid chlorides, thiocarbation, carboximethylation, phosphonomethylation, Michael addition to name just a few. So forth Polyvinylamine derivatives are also suitable for the production of crosslinked polymers II. The polymer-analogous reactions are preferably carried out before the crosslinking of the polyvinylamines, the copolymers and the graft copolymers of the "vinylamine".
• the proportion of the amino groups reacted in a polymer-analogous manner is up to 50%, preferably 10 to 30 mol%, of the amino groups of the polymer used.
• the polymers obtained by subsequent crosslinking are preferred, in particular those which have been desalted before the crosslinking step.
• polyethyleneimines polyamidoamines grafted with ethyleneimine or polyamines grafted with ethyleneimine
• reaction products of these polymer classes with ⁇ , ⁇ -unsaturated carboxylic acids, their esters or reaction products with the reaction products of formaldehyde with HCN or formaldehyde
• Another class of amino groups preferably polymers containing ethyleneimine units, is known from WO-A-94/12560. These are water-soluble, crosslinked, partially amidated polyethyleneimines, which are obtainable from
• the molar masses of the polyethyleneimines in question can be up to 5 million and are preferably in the range from 1000 to 1 million.
• the polyethyleneimines are partially identified with monobasic carboxylic acids, so that, for example, 0.1 to 90, preferably 1 to 50% of the amidatable nitrogen atoms in the polyethyleneimines is present as an amide group.
• Suitable crosslinkers containing at least two functional groups are mentioned above. Halogen-free crosslinkers are preferably used.
• crosslinking agents 0.1 to 50, preferably 1 to 5 parts by weight of at least one crosslinking agent is used, for example, for 1 part by weight of a compound containing amino groups.
• polyethyleneimines and quaternized polyethyleneimines are polyethyleneimines and quaternized polyethyleneimines.
• the Polyethyleneimines and the quaternized polyethyleneimines can optionally be reacted with a crosslinker containing at least two functional groups.
• the quaternization of the polyethyleneimines can be carried out, for example, with alkyl halides such as methyl chloride, ethyl chloride, hexyl chloride, benzyl chloride or lauryl chloride and with, for example, dimethyl sulfate. These reaction products may have to be desalinated.
• polyethyleneimines modified by the Strecker reaction, for example the reaction products of polyethyleneimines with formaldehyde and sodium cyanide with hydrolysis of the nitriles formed to give the corresponding carboxylic acids.
• These products can optionally be reacted with a crosslinker containing at least two functional groups or can crosslink with themselves with the formation of amides and the escape of water.
• alkoxylated polyethyleneimines which can be obtained, for example, by reacting polyethyleneimine with ethylene oxide and / or propylene oxide.
• the alkoxylated polyethyleneimines are reacted with a crosslinker containing at least two functional groups and are thus rendered water-insoluble.
• the alkoxylated polyethyleneimines contain 0.1 to 100, preferably 1-3 alkylene oxide units per NH group.
• the molecular weight of the polyethyleneimines can be up to two million.
• the alkoxylation uses polyethyleneimines with molecular weights of 1,000 to 50,000.
• Other suitable water-soluble amino group-containing polymers are reaction products of polyethyleneimines with diketenes, e.g. of polyethyleneimines with a molecular weight of 1,000 to 50,000 with distearyl diketene, which are then crosslinked.
• Crosslinked polyethyleneimines are described, for example, in EP 0895 521.
• the polyethyleneimine is produced in a conventional manner by cationic polymerization of ethyleneimine in the presence of polymerization catalysts such as acids, Lewis acids, acidic metal salts or alkylating reagents.
• polymerization catalysts such as acids, Lewis acids, acidic metal salts or alkylating reagents.
• Polyethyleneimines with a molecular weight of 1,000 to 5,000,000 (determined, for example, by static light scattering) are preferably crosslinked to give polymers II.
• Crosslinkers for the preparation of the hydrogel-forming polymers II are bifunctional or polyfunctional, that is to say they have two or more active groups which correspond to the amino or imino residues of the
• Polymers can react.
• polymers and copolymers which are preferably water-soluble, can also be used as crosslinkers.
• Suitable bifunctional or polyfunctional crosslinkers are, for example
• Di- and polycarboxylic acids and their acid derivatives (8) monoethylenically unsaturated carboxylic acids, their 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 Pat. No. 4,144,123. Phosphoric acid diglycidyl ether and ethylene glycol diglycidyl ether may also be mentioned.
• crosslinkers are the reaction products of at least trihydric alcohols with epichlorohydrin to reaction products which have at least two chlorohydrin units, e.g. the polyhydric alcohols used are glycerol, ethoxylated or propoxylated glycerols, polyglycerols having 2 to 15 glycerol units in the molecule and, if appropriate, ethoxylated and / or propoxylated polyglycerols.
• Crosslinkers of this type are known, for example, from DE-A-2 916 356.
• Suitable crosslinkers (2) are ⁇ , ⁇ - or vicinal dichloroalkanes, for example 1,2 dichloroethane, 1,2 dichloropropane, 1,3-dichlorobutane and 1, 6-dichlorohexane.
• EP-A-0 025 515 discloses ⁇ , ⁇ -dichloropolyalkylene glycols which preferably have 1 to 100, in particular 1 to 100, ethylene oxide units as crosslinkers.
• crosslinkers (3) which contain blocked isocyanate groups, for example trimethylhexamethylene diisocyanate blocked with 2, 2, 6, 6-tetramethylpiperidin-4-one.
• Such crosslinkers are known, cf. for example from DE-A-4 028 285.
• This crosslinker class also includes at least two reaction products of dicarboxylic acid esters with ethyleneimine and mixtures of the crosslinkers mentioned, which contain aziridino groups.
• Halogen-free crosslinkers of group (4) are reaction products which are prepared by reacting dicarboxylic acid esters which are completely esterified with monohydric alcohols having 1 to 5 carbon atoms with ethyleneimine.
• Suitable dicarboxylic acid esters are, for example, dimethyl oxalate, diethyl oxalate, dimethyl succinate, diethyl succinate, dimethyl adipate, diethyl adipate and dimethyl glutarate.
• the reaction of diethyl oxalate with ethyleneimine gives bis - [ß- (1-aziridino) ethyl] oxalic acid amide.
• the dicarboxylic acid esters are reacted with ethyleneimine, for example in a molar ratio of 1 to at least 4.
• Reactive groups of these crosslinkers are the terminal aziridine groups.
• n 0 to 22.
• crosslinkers (5) examples include ethylene carbonate, propylene carbonate, urea, thiourea, guanidine, dicyandiamide or 2-oxazolidinone and their derivatives. From this group of monomers, propylene carbonate, urea and guanidine are preferably used.
• Crosslinkers (6) are reaction products of polyether diamines, alkylenediamines, polyalkylene polyamines, alkylene glycols, polyalkylene glycols or their mixtures with monoethylenically unsaturated carboxylic acids, esters, amides or anhydrides of monoethylenically unsaturated carboxylic acids, the reaction products being at least two ethylenically unsaturated carboxylic acid, carboxylamides, carboxylamides, or unsubstituted carboxamides Have emergencester groups as functional groups, as well as methylene bisacrylamide and divinyl sulfone.
• Crosslinkers (6) are, for example, reaction products of polyether diamines with preferably 2 to 50 alkylene oxide units, alkylenediamines such as ethylenediamine, propylenediamine, 1,4-diamino-butane and 1,6-diaminohexane, polyalkylene polyamines with molecular weights ⁇ 5000, for example diethylene triamine, triethylene tetramine, dipropylenetriamine Tripropylenetetramine, dihexamethylenetriamine and aminopropylethylenediamine, alkylene glycols, polyalkylene glycols or mixtures thereof
• Crosslinking agents which are particularly preferred are the reaction products mentioned here of maleic anhydride with ⁇ , ⁇ -polyether diamines having a molecular weight of 400 to 5000, the reaction products of polyethyleneimines having a molecular weight of 129 to 50,000 with maleic anhydride and the reaction products of ethylenediamine or triethylenetetramine with maleic anhydride Molar ratio of 1: at least 2.
• the compounds of the formula are preferably used as crosslinker (6)
• halogen-free crosslinkers of group (7) are at least dibasic saturated carboxylic acids such as dicarboxylic acids and the salts, diesters and dia ide derived therefrom. These compounds can, for example, using the formula
• R1 CI to C 22 alkyl
• R 2 H, C ⁇ -C 22 alkyl
• n 0 to 22
• dicarboxylic acids of the abovementioned formula monoethylenically unsaturated dicarboxylic acids such as maleic acid or itaconic acid are suitable, for example.
• the esters of the dicarboxylic acids in question are preferably derived from alcohols having 1 to 4 carbon atoms.
• Suitable dicarboxylic acid esters are, for example Oxalcicredimethyl - ester, diethyl oxalate, Oxalcic Acidiisopropylester, succinate, Bernsteinkladredieethylester, diisopropyl succinate, Bernsteinkladi-n-propyl succinate, dimethyl adipate, adipic acid diethyl ester and adipate or at least 2 Ester phenomenon containing Michael addition products of polyetherdiamines, polyalkylenepolyamines, or ethylene diamine, and esters of Acrylic acid or methacrylic acid, each with monohydric alcohols containing 1 to 4 carbon atoms.
• Suitable esters of ethylenically unsaturated dicarboxylic acids are, for example, dimethyl maleate, diethyl maleate, diisopropyl maleate, dimethyl itaconate and diisopropyl itaconate.
• Substituted dicarboxylic acids and their esters such as tartaric acid (D, L form and as a racemate) and tartaric acid esters such as tartaric acid dimethyl ester and tartaric acid diethyl ester are also suitable.
• Suitable dicarboxylic anhydrides are, for example, maleic anhydride, itaconic anhydride and succinic anhydride.
• crosslinkers (7) are dimethyl maleate, diethyl maleate and maleic acid.
• the crosslinking of compounds containing amino groups with the above-mentioned crosslinkers takes place with the formation of amide groups or in the case of amides such as adipic acid diamide by transamidation.
• Maleic acid esters, monoethylenically unsaturated dicarboxylic acids and their anhydrides can bring about crosslinking both by forming carboxamide groups and by adding NH groups to the component to be crosslinked (for example polyamidoamines) in the manner of a Michael addition.
• the at least dibasic saturated carboxylic acids of crosslinker class (7) include, for example, tri- and tetracarboxylic acids such as citric acid, propane tricarboxylic acid, nitrilotriacetic acid, ethylenediaminetetraacetic acid, butanetetracarboxylic acid and diethylenetriaminepentaacetic acid.
• the crosslinkers of group (7) also include the salts, esters, amides and anhydrides derived from the aforementioned carboxylic acids, e.g. Tartaric acid dimethyl ester, tartaric acid diethyl ester, adipic acid dimethyl ester, adipic acid diethyl ester into consideration.
• Suitable crosslinkers of group (7) are also polycarbonic acids which can be obtained by polymerizing monoethylenically unsaturated carboxylic acids, anhydrides, esters or amides.
• mono-unsaturated carboxylic acids include Acrylic acid, methacrylic acid, fumaric acid, maleic acid and / or itaconic acid.
• Suitable crosslinkers are e.g. Polyacrylic acids, copolymers of acrylic acid and methacrylic acid or copolymers of acrylic acid and maleic acid. Examples of its comonomers are its vinyl ethers, vinyl formate, vinyl acetate and vinyl lactam.
• crosslinkers (7) are produced, 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.
• anhydrides such as maleic anhydride
• an inert solvent such as toluene, xylene, ethylbenzene, isopropylbenzene or solvent mixtures.
• copolymers of maleic anhydride are suitable, for example copolymers of acrylic acid and maleic anhydride or copolymers of maleic anhydride and a C to C 30 olefin.
• Preferred crosslinkers (7) are, for example, copolymers of maleic anhydride and isobutene or copolymers of maleic anhydride and diisobutene.
• the copolymers containing anhydride groups can optionally be modified by reaction with C 1 -C 20 alcohols or ammonia or amines and can be used in this form as crosslinking agents.
• Preferred polymeric crosslinkers (7) are, for example, copolymers of acrylamide and acrylic esters, such as, for example, hydroxyethyl acrylate or methyl acrylate, the molar ratio of acrylamide and acrylic esters can vary from 90:10 to 10:90.
• terpolymers can also be used, it being possible, for example, to use combinations of acrylamide, methacrylamide, acrylic esters or methacrylic esters.
• the molecular weight M w of the homopolymers and copolymers is, for example, up to 10,000, preferably 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.
• the at least dibasic saturated carboxylic acids and the polycarboxylic acids can also be used as crosslinking agents in the form of the alkali metal or ammonium salts.
• the sodium salts are preferably used.
• the polycarboxylic acids can be partially, for example 10 to 50 mol%, or completely neutralized.
• Suitable halogen-free crosslinkers of group (8) are, 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 with 1 to 22, preferably 1 to 18, carbon atoms.
• the amides are preferably unsubstituted, but can carry a C 1 -C 2 -alkyl radical as a substituent.
• Crosslinkers (8) which are preferably used are acrylic acid, methyl acrylate, ethyl acrylate, acrylamide and methacrylamide.
• Suitable halogen-free crosslinkers of group (9) are e.g. Dialdehydes or their semi- or acetals as precursors, such as, for example, glyoxal, methylglyoxal, malondialdehyde, succindialaldehyde, maleic and fumaric acid dialdehyde, tartaric dialdehyde, adipindialdehyde, 2 -oxi -adipindialdehyde, furan-2, 5 -dipropionalde Formyl-2,3-dihydropyran, glutardialdehyde, pimelic acid aldehyde and aromatic dialdehydes such as, for example, terephthalaldehyde, o-phthalaldehyde, pyridine-2, 6 -dialdehyde or phenylglyoxal.
• Dialdehydes or their semi- or acetals as precursors, such as, for example, gly
• homo- or copolymers of acrolein of methacrolein with molar masses from 114 to approximately 10,000 can also be used.
• all water-soluble comonomers can be used, such as, for example, acrylamide, vinyl acetate and acrylic acid.
• Aldehyde starches are also suitable as crosslinkers.
• Suitable halogen-free crosslinkers of group (9) are, for example, diketones or the corresponding half or ketals as precursors such as, for example, ⁇ -diketones such as acetylacetone or cycloalkane-1, n-dione such as, for example, cyclopentane-1,3-dione and cyclohexane-1 , 4-dione.
• ⁇ -diketones such as acetylacetone or cycloalkane-1
• n-dione such as, for example, cyclopentane-1,3-dione and cyclohexane-1 , 4-dione.
• homo- or copolymers of methyl vinyl ketone with molecular weights from 140 to about 15,000 can also be used.
• all water- soluble monomers such as acrylamide, vinyl acetate and acrylic acid are used.
• halogen-free crosslinking agents are therefore preferably used for the production of crosslinked polymers II, which are each insoluble in water.
• crosslinking agents described above can be used either alone or in a mixture in the reaction with water-soluble polymers containing amino groups or polyalkylene polyamines. In all cases, the crosslinking reaction is carried out to such an extent that the resulting products are no longer water-soluble but are still water-swellable.
• the crosslinking reaction takes place by heating the reaction components at temperatures from room temperature to 220, preferably at temperatures from
• the crosslinking reaction is carried out in an aqueous medium at temperatures above 100 ° C., it is advantageous to distill off the condensate formed (water, lower alcohols, ammonia, amines) together with the dilution water present until the reaction mixture has solidified.
• the polymer film is then comminuted and, if appropriate, ground with cooling using dry ice.
• Polymers II are also preferred, to which no crosslinking agents have been added, but which are based on their comonomers
• Comonomers suitable for self-crosslinking are acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters and their homologues, as well as acrylamide and acrylonitrile.
• Copolymers based on acrylic or methacrylic acid esters or their homologs are particularly suitable for self-crosslinking, but also those based on acrylic or methacrylic acid or their homologs.
• the proportion of N-vinylformamide is usually between 50 and 99 mol%, that of the comonomers between 1 and 50 mol%.
• a fraction of 5-15 mol% as a comonomer fraction and 85-95 mol% as an N-vinylformamide fraction is particularly advantageous, the sum of the monomer fractions always being 100 mol%.
• Such copolymers are initially practical under basic conditions completely saponified, optionally desalted and then crosslinked at temperatures of 80-220, preferably 120-180 ° C. If appropriate, the crosslinking of such copolymers can be accelerated by further addition of polyvinylamines or polyethyleneimines.
• thermal self-crosslinking can also be observed with polyvinylamine. This can be explained by the remaining formamide groups, which are also present after the hydrolysis, and by condensation with the escape of ammonia, secondary amines being formed.
• the ratio of the formamide groups to the amino groups can be 30/70 to 0/100, and is preferably 15/85 to 5/95.
• the self-crosslinking of the polyvinylamine is carried out in aqueous solution at temperatures from 100 to 200 ° C., preferably 150 to 180 ° C.
• the polyvinylamine to be crosslinked is applied in thin layers.
• Polyvinylamine with a K value of 70-200, particularly preferably 100-150, is preferably itself crosslinked, since this leads to hydrogel-forming polymers with advantageous properties.
• the ratios in which the two hydrogel-forming polymers I and II are mixed with one another depend, in addition to other influencing variables, primarily on the density of the acid or amine groups (val / g) and the acid or base strengths.
• Mixing ratios can vary in a range from 20: 1 to 1:20 (weight).
• Mixing ratios between 10: 1 and 1:10 are preferred, particularly preferably between 7: 3 and 3: 7.
• All commercially available aggregates for mixing powders are suitable for mixing the separately prepared powders.
• the particle size of the particles to be mixed is between 10 and 2000 ⁇ m, preferably between 100 and 850 ⁇ m. It is possible to mix the two components of the same as well as different particle sizes.
• the use of different particle sizes in the two components can be advantageous in that differences in the uptake rate or the ion exchange rate of the two components can be coordinated with one another. It can also be advantageous to use one component in relatively coarse particles and the other in very fine particles, so that the fine-particle component is agglomerated on the surface of the coarser-particle component.
• this process can be supported by adding agglomeration aids such as polyethylene glycols, water and / or polyols.
• agglomeration aids such as polyethylene glycols, water and / or polyols.
• Another possibility is to use very finely divided powders of both components and to agglomerate them with the addition of agglomeration aids as listed above to form agglomerates with a size between 100 ⁇ m and 1500 ⁇ m. It can also be advantageous to combine this agglomeration with a surface postcrosslinking in such a way that the postcrosslinking also brings about the agglomeration.
• agglomeration (regardless of which variant) is to be seen in the fact that particles are formed in this way which contain both components together, so that when these mixtures are used in, for example, hygiene articles, no separation of the two components can occur. This effect is particularly pronounced when mixtures with very different particle sizes of the two components are used.
• the separation of both components means that long diffusion paths have to be overcome in the ion exchange process, which can lead to locally strongly acidic or basic pH values. This behavior is not acceptable for use in hygiene articles.
• Agglomeration also has the advantage that high absorption speeds can be achieved without having to use very finely divided powders which are undesirable because of their dust generation.
• Another way of avoiding the problem of component separation described above is to mix the aqueous gels intimately and then to dry, mill and, if necessary, sieve them. Particles are obtained which contain both components firmly bonded to one another, so that a separation of the two components is not possible. It is to be expected that Build strong ionic interactions in the boundary layer of the two gel components and thus firmly connect the basic and acidic components to one another (see DE-A-19640329). The formation of a classic polyelectrolyte complex is not to be expected, since the two polyelectrolytes are each integrated in a separate network. Since both components are produced as aqueous gels, it is advantageous to use a mixture of these gels.
• the mixing itself can be done with different equipment, such as meat grinders, kneaders, extruders, planetary roller extruders or mixers.
• the equipment used must ensure homogeneous, fine-particle mixing of the two components without damaging the network structure of the gels due to excessive shear.
• the water content of the mixed gels is between 5 and 99.8% by weight, preferably between 60 and 99% by weight.
• Gels can be the same or different. Another advantage of this variant is the fact that it dries faster, is easier to grind, in addition, no separate drying steps are required and the gel mixtures obtained have a higher gel strength and thus easier handling.
• the powdered component will have an island structure in a matrix of the component used in gel form. Depending on the desired range of properties, it can be advantageous to implement one or the other structure.
• Another option for obtaining immiscible products is the addition of powders or gels of one component to the reaction mixture of the other component.
• the addition of polymer I, for example polyacrylic acid, as a powder or gel to the polyvinylamine solution and subsequent crosslinking of the polyvinylamines leads to mixtures with advantageous properties.
• This crosslinking can take place by adding a crosslinker or thermally as self-crosslinking.
• crosslinked polyvinylamine as a powder or gel to polymer I, e.g. Polyacrylic acid and subsequent crosslinking mixtures with advantageous properties. It is important to ensure that there are no undesired reactions. For example, when adding crosslinked polyvinylamine to a reaction mixture of acrylic acid crosslinking agent and initiator, a Michael addition between the primary amino groups of the gel and the acrylic acid immediately begins. Provided that no undesired reactions can occur, it is possible to add the powder or a gel to the reaction mixture of the other component at any time during the course of the reaction. With this variant, it can be expected that products are obtained whose boundary layer between the components has a different structure than in the case of
• Gel or powder mixtures One of the two components here is at least partially still uncrosslinked, or even as a monomer mixture.
• more orderly structures with stronger interactions up to polyelectrolyte complexes can form in the boundary layer and it is to be expected that the boundary layer will be significantly thicker than in the previous variants. This effect should increase the stability of the gel and also influence the range of properties that can be achieved in terms of surface post-crosslinking.
• Another possibility is the production of a core-shell structure. Particles of one component are coated with a reaction mixture for producing the second component, for example by spraying. After or during the reaction, the core-shell product obtained is dried. To achieve certain layer thicknesses, it may be necessary to repeat the coating several times. On the other hand, it is also conceivable to build up multilayer particles with alternating layers of the two components using such a method. Process control in a fluidized bed is particularly suitable for the construction of simple, but in particular complex, layer structures. The main advantage of such a procedure is that defined structures can be produced with uniform and specifically adjustable layer thicknesses.
• the hydrogel-forming polymers can be dried by various methods known to the person skilled in the art.
• suitable drying processes are thermal convection drying such as tray, chamber, channel, flat track, plate, rotating drum, trickle shaft, sieve belt, current, fluidized bed, fluidized bed, paddle and ball bed drying, thermal Contact drying such as heating plate, roller, belt, screen drum, screw, wobble and contact disk drying, radiation drying such as infrared drying, dielectric drying such as microwave drying, and freeze drying.
• drying In order to avoid undesired decomposition and crosslinking reactions, it can be advantageous to carry out the drying under reduced pressure, under a protective gas atmosphere and / or under gentle thermal conditions in which the product temperature does not exceed 120 ° C., preferably 100 ° C.
• Particularly suitable drying methods are (vacuum) belt drying and paddle drying.
• the dried hydrogel-forming polymers are optionally comminuted and then ground by methods known to those skilled in the art, for example with the aid of a roller mill or a hammer mill.
• the particle size distribution is set, which is generally between 100 and 1000 ⁇ m, preferably between 120 and 850 ⁇ m. Particles that are too coarse can be subjected to grinding again, particles that are too fine can be returned to the production process.
• polymers I and II can be post-crosslinked in a known manner in an aqueous gel phase or post-crosslinked as dried, ground and sieved polymer particles.
• the absorption properties of the mixtures of polymers I and polymers II thus obtained are further improved by a subsequent surface postcrosslinking.
• An exclusive crosslinking of the polymers I, an exclusive crosslinking of the polymers II or a crosslinking of a homogeneous mixture of both types of polymer can take place.
• connections with the functional groups of the polymers can react with crosslinking, preferably applied in the form of a water-containing solution to the surface of the hydrogel particles.
• the water-containing solution can contain water-miscible organic solvents. Suitable solvents are alcohols such as methanol, ethanol, i-propanol or acetone.
• Suitable post-crosslinking agents are, for example
• Di- or polyglycidyl compounds such as phosphonic acid diglycidyl ester or ethylene glycol diglycidyl ether, bischlorohydrin ether of polyalkylene glycols,
• Polyaziridines compounds containing aziridine units based on polyethers or substituted hydrocarbons, for example bis-N-aziridinomethane,
• Polyols such as ethylene glycol, 1, 2-propanediol, 1, 4-butanediol, glycerol, methyltriglycol, polyethylene glycols with an average molecular weight M w of 200-10000, di- and polyglycerol, pentaerythritol, sorbitol, the oxyethylates of these polyols and their esters Carboxylic acids or carbonic acid such as ethylene carbonate 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 glyoxal, succinic aldehyde or aldehyde starch,
• Di- and poly-N-methylol compounds such as, for example, methylenebis (N-methylol-methacrylamide) or melamine-formaldehyde resins,
• Di- and polyhalogen compounds such as ⁇ , ra-dichloropolyalkylene glycols, ⁇ , cj- or vicinal dichloroalkanes e.g. 1,2-dichloroethane, 1, 2-dichloropropane, 1, 3-dichlorobutane or 1.6 dichlorohexane,
• monoethylenically unsaturated carboxylic acids such as (meth) acrylic acid or crotonic acid, and their esters, amides, and anhydrides.
• acidic catalysts such as p-toluenesulfonic acid, phosphoric acid, boric acid or ammonium dihydrogen phosphate can be added.
• Particularly suitable postcrosslinking agents are di- or polyglycidyl cidylENSen such as ethylene glycol diglycidyl ether, the reaction products of polyamidoamines with epichlorohydrin and which can react with both amino and carboxyl groups under Ver ⁇ networking 2-oxazoline lidinon.
• Suitable known in the art mixing apparatus for spraying of the crosslinker solution to the poly ⁇ mer particles are, for example, Patterson-Kelly mixer, DRAIS turbulence mixers, Lödige mixers, NARA-blade mixers, screw mixers, pan mixers, fluidized bed dryer, Schugi mixer (Flexo -Mix) or PROCESSALL.
• Kitchen mixers such as a WARING blender are suitable for crosslinking small quantities on a laboratory scale.
• a temperature treatment step can follow, preferably in a downstream dryer, at a temperature between 80 and 230 ° C, preferably 80-190 ° C, and particularly preferably between 100 and 160 ° C, over a period of 5 minutes up to 6 hours, preferably 10 minutes to 2 hours and particularly preferably 10 minutes grooves up to 1 hour, whereby both fission products and solvent components can be removed.
• drying can also take place in the mixer itself, by heating the jacket or by blowing in a preheated carrier gas.
• these domains or region boundaries can also be crosslinked by thermal treatment without the addition of a crosslinking agent.
• the water content of the particles before this temperature treatment is preferably 0 to 50% by weight, particularly preferably 1 to 30% by weight and most preferably 2 to 20% by weight.
• the temperature in this annealing step is between 80 and 230 ° C., preferably 80-190 ° C., and particularly preferably between 100 and 160 ° C., over a period of 5 minutes to 6 hours, preferably 10 minutes to 2 hours and particularly preferably 10 Minutes to 1 hour.
• the temperature treatment step can be carried out after the particles have been dried in a downstream dryer, and the desired water content of the particles can be obtained by spraying on water or a mixture consisting of water and one or more water-miscible organic solvents.
• the temperature treatment step is preferably carried out when the hydrogel particles are dried by first drying the hydrogel to a desired water content and then subjecting it to the temperature treatment.
• the temperature treatment can be carried out in a separate dryer or, preferably, in the same drying apparatus that was also used to dry the hydrogel to the desired water content.
• Heat treatment at the domain or region boundaries form the acid groups of the polymer I with the amino groups of the polymer II covalent amide bonds, so that there is an additional crosslinking.
• the hydrophilicity of the particle surface of the mixtures of polymers I and polymers II is additionally modified by the formation of complexes.
• the complexes are formed on the outer shell of the hydrogel particles by spraying on solutions of di- or polyvalent metal salt solutions and / or di- or polyvalent anions, the metal cations with the functional groups of the anionic polymer and the polyvalent anions with can react with the functional groups of the cationic polymer to form complexes.
• divalent or polyvalent metal cations are Mg 2+ , Ca 2+ , Al 3+ , Sc 3+ , Ti 4+ , Mn 2+ , Fe 2 + / 3 +, Co 2 + / Ni 2 + cu + / 2+ , Zn 2+ , Y 3+ , Zr + , Ag + , La 3+ , Ce 4+ , Hf 4+ , and Au + / 3+
• preferred metal cations are Mg 2+ , Ca 2+ , Al 3+ , Ti 4+ , Zr 4+ and La 3+
• particularly preferred metal cations are Al 3+ , Ti 4+ and Zr 4+ .
• divalent or polyvalent anions examples include sulfate, phosphate, borate and oxalate.
• metal cations and the polyvalent anions mentioned all salts are suitable which have sufficient solubility in the solvent to be used.
• Water, alcohols, DMF, DMSO and mixtures of these components can be used as solvents for the salts.
• Water and water / alcohol mixtures such as water / methanol or water / 1,2-propanediol are particularly preferred.
• the salt solution can be sprayed onto the particles of the mixture of hydrogel-forming polymers I and II both before and after the surface post-crosslinking of the particles.
• the salt solution is sprayed on in the same step as the spraying of the crosslinking agent solution, with both solutions being sprayed on separately in succession or simultaneously via two nozzles, or the crosslinking agent and salt solution being sprayed together via a nozzle .
• a further modification of the particles of the mixture of polymers I and polymers II can be carried out by admixing finely divided inorganic solids, such as, for example, silica, bentonite, aluminum oxide, titanium dioxide and iron (III) oxide, which further enhances the effects of surface treatment become.
• finely divided inorganic solids such as, for example, silica, bentonite, aluminum oxide, titanium dioxide and iron (III) oxide.
• hydrophilic silica or of aluminum oxide with an average size of the primary particles of 4 to 50 nm and a specific surface area of 50-450 m 2 / g is particularly preferred.
• Fine inorganic solids are preferably added after the surface modification by crosslinking / complex formation, but can also be carried out before or during these surface modifications.
• additives are finely divided, powdery or fibrous substances which are inert to the manufacturing conditions of the components and the mixtures, and which can be organic or inorganic in nature. Examples of such additives are:
• the gels to be handled in the preparation of mixtures according to the invention are all sticky in more or less pronounced form. In order to overcome this disadvantage, it can be particularly useful when grinding, mixing or drying,
• the carrier material can simply be added to the reaction mixture during the production of the components.
• the carrier material can simply be added to the reaction mixture during the production of the components.
• the support material e.g. by spraying in a fluidized bed.
• the amounts of carrier material used are between 5% and 80%.
• Surfactants and blowing agents can also be used as auxiliaries.
• saline solution at least 0.83 1 saline solution / l g polymer powder.
• the teabag is removed from the saline solution and centrifuged at 250 g for three minutes. The amount of liquid held in place by the polymer powder is determined by weighing the centrifuged tea bag.
• the PUP 1.4 psi is determined in the same way as the PUP 0.7 psi, but under a weight load of 1.4 psi (9653 Pa).
• the PUP 0.014 psi is determined analogously to the determination of the PUP 0.7 psi, but under a weight load of 0.014 psi (96.5 Pa), i.e. without weight, only with the plastic insert for the weight.
• the SFC index is obtained from three SFC measurements with different weight loads using the following formula:
• the SFC (0.6 psi) swells the hydrogel and measures the flow under a weight load of 0.6 psi (4137 Pa), with the SFC (0.9 psi) swelling and flow measurement are carried out at a weight load of 0.9 psi (6205.5 Pa).
• the pressure absorbency index (NaCl) is determined in accordance with the description of the PAI test method in EP-A-0 615 736, with the difference of a measurement time which is extended by up to 16 hours.
• the determination of the Pressure Absorbency Index is carried out analogously to the determination of the Pressure Absorbency Index (NaCl) described above, but the liquid to be absorbed is, in deviation, a synthetic urine replacement solution with the following composition: 1000 g distilled water, 2.0 g KC1, 2, 0 g Na 2 S0 4 , 0.85 g (NH 4 ) H 2 P0, 0.15 g (NH 4 ) 2 HP0 4 , 0.19 g CaCl 2 , 0.23 g MgCl 2 .
• the method for determining the diffusing absorbency under pressure is carried out analogously to the description in EP-A-0712 659, but with the following modifications: the weight of polymer is 0.9 g instead of 1.5 g; the polymer sample is measured in the grain size range 106 - 850 ⁇ m; the weight load on the measurement is 0.7 psi (4826.5 Pa) instead of 0.3 psi (2068.5 Pa); the test solution is the synthetic urine replacement solution (see PAI) instead of 0.9% by weight saline; the measuring time is 4 hours instead of 1 hour.
• the measurement of the wicking performance is carried out analogously to the measurement of the wicking parameter as described in the
• EP-A-0 532 002 In contrast to the measurement of the Wikking parameter, the measurement of the wicking performance with 2 g polymer (particle size distribution 106 - 850 ⁇ m) is only carried out with a degree of pre-swelling of 10 g 0.9% by weight NaCl solution / lg polymer. guided. The wicking distance is measured, which indicates the length to which the polymer particles have swollen with the blue colored test liquid after a test time of 1 h and the Wikking capacity, which corresponds to the amount of liquid additionally taken up during this time.
• the plastic plate is placed on the pad so that the center of the pad is also the center of the feed ring. 80 ml of synthetic urine replacement solution are applied three times.
• the synthetic urine replacement solution is prepared by dissolving 1.14 g of magnesium sulfate heptahydrate, 0.64 g of calcium chloride, 8.20 g of sodium chloride, 20 g of urea in 1 kg of deionized water.
• the synthetic urine replacement solution is measured in a measuring cylinder and applied to the pad in one shot through the ring in the plate. Simultaneously with the task, the time is measured which is necessary for the solution to penetrate completely into the pad. The measured time is noted as Acquisition Time 1.
• the pad is then loaded with a plate for 20 minutes, the load being kept at 13.6 g / cm2. After this time the plate is removed, 10 g ⁇ 0.5 g of the filter paper (Schleicher & Schuell, 1450 CV) are placed on the center and with a weight (area 10 x 10 cm, weight 3.5 kg) for 15 s charged. After this time, the weight is removed and the filter paper is weighed back. The weight difference is noted as Rewet 1. Then the plastic plate with the feed ring is placed on the pad again and the second application of the liquid takes place. The measured time is noted as Acquisition Time 2. The procedure is repeated as described, but 45 g ⁇ 0.5 g filter paper is used for the Rewet examination. Rewet 2 is noted. The same procedure is used to determine acquisition time 3. When determining Rewet 3, 50 g ⁇ 0.5 g filter paper are used.
• the rest (11 g) of the pre-swollen gel after removal of the amount of gel for the double determination described above is transferred to a 30 x 150 mm polyethylene bag and the open side of the bag is vacuum-sealed.
• the bag is fixed on a film bag tester with an adhesive strip and then subjected to a roll-down test, which means that it is rolled over 50 times with a roll of 2 kg (25 times in the opposite direction).
• the mechanically loaded gel obtained in this way is now used in the same way as described above for absorption under a pressure load of 50 g / cm 2 (re-absorbing capacity of sheared gel).
• the weight of the measuring cell with gel and disk before the 60 minute absorption is recorded as W3, the weight after absorption as W4.
• the re-absorbing capacity factor is now understood to be the ratio of absorption after to absorption before shear of the gel, multiplied by 100:
• RAC-Factor [(W4 - W3) / initial weight gel sheared / 10)] • 100 / [(W2 - Wl) / (initial weight gel unsheared / 10)]
• the method for determining DATGLAP is divided into two stages.
• an AUL Absorption Under Load
• 0.7 psi 4826.5 Pa
• the same measuring cell and the same equipment are used and the procedure is almost identical to that for determining the PUP 0 , 7 psi, which is described in US 5,599,355.
• the DATGLAP / level 1 differs from the PUP in two points:
• the Covered ring has an outer diameter of 5.98 cm so that it can be moved upwards without jamming / tilting in the measuring cell when the gel swells, an inner diameter of 4.9 cm and a height of 0.32 cm.
• the plastic cover plate with the weight is then placed on the covered ring, as described in the US patent cited above.
• a new measuring unit of the same type as described above (but smaller diameter, into the plexiglass cylinder) is placed on the covered plexiglass ring remaining in the measuring cell and resting on the gel after removing the weight and the plastic cover plate first measuring stage), set and left for 4 hours.
• the measurement of the liquid absorption begins again when the second measuring unit is placed on the sieve ring of the first measuring unit.
• DATGLAP (DAAP-TGL / DAAP-Regular) • (DAAP-Regular + DAAP-TGL) [g / g]
• DAAP-TGL Demand Absorbency against Pressure Through Gel Layer after 4 hours, in [g / g]
• Polymer mixtures with an SFC index of at least 10,000, preferably> 100,000, in particular> 200,000 and particularly preferably 300,000 are preferred.
• CRC, PUP 0.014 psi, PUP 0.7 psi and PUP 1.4 psi, PAI (NaCl) and PAI (Jayco) are test methods for characterizing the absorbency of the polymer mixture for aqueous saline solutions under different pressure loads.
• SFC, SFC index and Wicking performance describes the permeability of swollen gel layers.
• Diffusing Absorbency Under Pressure and DATGLAP provide test methods for the combined detection of ab- sorption capacity and fluid conduction.
• the RAC factor characterizes the mechanical stability of swollen polymer particles.
• the Acquisition Time / Rewet under pressure test simulates the behavior of the polymer mixture in hygiene articles such as 5 baby or incontinence diapers.
• polymer mixtures with a Pressure Absorbency Index (NaCl) of> 100, preferably> 130, in particular 150 and particularly preferably 180 after a swelling time of 16 h, preferably of 4 h, are particularly suitable for use in hygiene articles.
• NaCl Pressure Absorbency Index
• polymer mixtures are preferred which have a Pressure Absorbency Index (Jayco) of at least 150, preferably> 15 200, in particular> 225 and particularly preferably> 250 after a swelling time of 16 h, preferably 4 h.
• Bennett Pressure Absorbency Index
• polymer mixtures with a diffusing absorbance under pressure of at least 30 g / g, preferably> 40 g / g, 20 in particular> 45 g / g and particularly preferably 50 g / g are advantageous.
• polymer mixtures which, in the wicking performance test, have a wicking distance of at least 5 cm, preferably> 25 8 cm, in particular 10 cm and particularly preferably 15 cm and a wicking capacity of at least 5 g, preferably 8 g, in particular 10 g particularly preferably have> 13 g.
• polymer mixtures which, in the Acquisition 30 Time / Rewet under pressure test, have an Acquisition Time 3 of at most 25 s, preferably 20 s, in particular ⁇ 15 s, very particularly ⁇ 10 s and a Rewet 3 of at most 9 g, preferably ⁇ 5 g, in particular ⁇ 3 g and particularly preferably ⁇ 2 g.
• Polymer mixtures are also preferred which have a RAC factor of at least 80, preferably> 90, in particular> 100 and particularly preferably> 120.
• polymer mixtures with a DATGLAP of at least 40 at least 50 g / g, preferably 65 g / g, in particular> 80 g / g and very particularly preferably 90 g / g are advantageous.
• polymers are preferred which have several of these preferred properties.
• Polymer mixtures with a 45 SFC index> 10,000 and a wicking distance of> 5 cm and a wicking capacity of at least 5 g are preferred.
• Polymer mixtures with an acquisition time 3 are particularly preferred of at most 25 s and a Rewet 3 of at most 9 g and an SFC> 10,000 and / or a diffusing absorbance under pressure of> 30 g / g.
• Polymer mixtures with an SFC index of> 1000, a PAI of> 150 after a 5 swelling time of 16 h, a diffusing absorbance under pressure of at least 30 g / g, a wicking distance of 5 cm and a Wikking are very particularly preferred Capacity of 5 g, an acquisition time 3 of at most 25 s and a rewet 3 of at most 9 g.
• Polymer mixtures with polymers I based on acrylic acid and / or methacrylic acid are preferred.
• Polymer mixtures whose polymer I is a crosslinked polyacrylic acid and whose carboxylic acid groups of 0 to 15-50% are present as an alkali and / or ammonium salt are preferred.
• Polymer mixtures with crosslinked copolymers of acrylic acid or methacrylic acid with vinylsulfonic acid or acrylamidopropanesulfonic acid are also preferred as polymers I.
• polymers I have been crosslinked with oligo- or polyethylene glycol diacrylates or methacrylates, the molecular weight of which was 200 to 1000.
• Preferred polymer mixtures are those in which polymer II is a polyethyleneimine, a polyamidoamine grafted with ethyleneimine, and / or polyamine grafted with ethyleneimine, which are crosslinked.
• Polymer mixtures whose polymer II is a crosslinked polyvinylamine are also preferred.
• polymer mixtures the polymer II of which was obtained by copolymerization of vinylformamide and one or more mono-ethylenically unsaturated compounds, subsequent hydrolysis and optionally desalting and subsequent crosslinking.
• Polymer mixtures are preferred, the polymer II of which is a graft copolymer of vinylformamide onto polymeric compounds, which has subsequently been hydrolyzed, optionally desalted and crosslinked.
• Preferred polymer mixtures are those whose polymer II is a copolymer of vinylformamide and monoethylenically unsaturated mono- and / or polycarboxylic acids, which is then hydrolyzed. siert, optionally desalted and self-crosslinked by heating, that is, without the addition of crosslinker.
• Preferred polymer mixtures are those whose polymer II is a copolymer of vinylformamide and monoethylenically unsaturated mono- and / or polycarboxylic acids which has been hydrolyzed, optionally desalted, has been crosslinked by heating and then with a cationic polymer or copolymer based on polyvinylamine or polyethyleneimine and / or with at least one bifunctional crosslinker was further crosslinked.
• polymer mixtures the polymer II of which is a polyethyleneimine, a polyamidoamine grafted with ethyleneimine or a polyamine grafted with ethyleneimine, which has been polymer-analogously modified by reaction with ⁇ , ⁇ -unsaturated carboxylic acids, their esters or by Strecker reaction and then thermally was networked with itself or at least one crosslinker.
• polymer mixtures the polymer II of which has been obtained by crosslinking a polyvinylamine with a K value of 40 to 220, in particular 70 to 160.
• polymer mixtures whose polymer II has been prepared with one or more crosslinkers from groups (1), (5), (6), (7), (8) and (9).
• Polymer mixtures with a ratio of the acid residues to the sum of amino / imino residues of 2: 1 to 1: 8 are preferred.
• Polymer mixtures which are obtained by mixing polymer gel I and polymer gel II are preferred.
• Polymer mixtures obtained by mixing polymer gel I and polymer powder II or polymer powder I and polymer gel II are particularly preferred.
• Polymer mixtures which are obtained as a powder in the reaction mixture of the other component by adding a mixture component I or II are particularly preferred.
• Polymer mixtures which contain polymer powder I, polymer powder II and agglomeration aids are also preferred.
• Preferred polymer mixtures are those obtained by mixing surface post-crosslinked polymer I and surface post-crosslinked polymer II.
• the intraparticulate Lärischen mixtures with a domain structure, island structure and / or core-shell structure are preferred.
• Polymer mixtures which are an agglomerated, surface post-crosslinked powder mixture are also preferred.
• the polymer mixtures according to the invention have good application properties. They have an advantageous SFC index, good PAI values as well as table salt and Jayco. They also show excellent diffusing absorbency under pressure. They also get good results in the Wicking Performance test. Of particular note are their good values in the Acquisition Time / Rewet test under pressure.
• the polymer mixtures according to the invention are notable for excellent absorbency for water and aqueous, salt-containing solutions, for high permeability of the swollen gel layers and for great mechanical stability of the swollen polymer particles and are therefore outstanding as absorbents for water and aqueous liquids, in particular body fluids 'n, such as urine or blood suitable, for example in hygiene articles such as baby and adult diapers, sanitary napkins, tampons and the like.
• body fluids 'n such as urine or blood suitable
• hygiene articles such as baby and adult diapers, sanitary napkins, tampons and the like.
• they can also be used as soil improvers in agriculture and horticulture, as moisture binders for cable sheathing and for thickening aqueous waste.
• the nitrogen flow is switched off and the gas inlet tube is removed from the Dewar pulled out.
• part of the gel block obtained was comminuted in a meat grinder and dried in a vacuum drying cabinet at 85 ° C. overnight in a vacuum. The second part was used for further tests without additional treatment.
• the dried gel was ground and the fraction was sieved with a particle size between 100 ⁇ m and 850 ⁇ m.
• aqueous polyvinylamine solution (K value 85) are homogeneously at room temperature with a solution of 13.77 g of ethylene glycol diglycidyl ether in 100 g of dist. Mixed water. The mixture is then heated in a water bath at 75 ° C. for 2 hours. Part of the gel obtained is used directly for further experiments, the rest is dried at 85 ° C. and vacuum overnight. The product obtained is ground and the fraction with a particle size between 100 ⁇ m and 850 ⁇ m is sieved off.
• Example la produced poly acryl Acid Acid and 157.30 g undried according to Example lb Polyvinylamingels) produced are thereby intimately mixed with each other ge ⁇ that they are rotated together 3 times through a commercial meat grinder.
• the gel mixture obtained is dried in vacuo at 85 ° C. overnight. After grinding, the fraction with a particle size between 100 microns and 850 microns is sieved.
• aqueous polyvinylamine solution K value 85
• a solution of 0.63 g of ethylene glycol diglycidyl ether in 4.38 g of dist Water is mixed homogeneously at room temperature.
• 12.5 g of the powdery, crosslinked polyacrylic acid prepared according to Example la) are likewise homogeneously mixed in by vigorous stirring.
• the reaction mixture is heated to 75 ° C. in a water bath for 2 hours.
• the gel obtained is crushed, dried at 85 ° C. and vacuum overnight, ground and the fraction is sieved with a particle size between 100 ⁇ m and 850 ⁇ m.
• aqueous polyethyleneimine solution (MW approx. 500000) is mixed homogeneously with 2.99 g of ethylene glycol diglycidyl ether at room temperature. The mixture is then heated in a water bath at 75 ° C. for 2 hours. Part of the gel obtained is used directly for further experiments, the rest is dried at 85 ° C. and vacuum overnight. The product obtained is ground with the addition of dry ice and the fraction with a particle size between 100 ⁇ m and 850 ⁇ m is sieved off.
• the two gels are each mechanically comminuted and the comminuted gels are mixed together in a ratio of 1: 1, based on the solids content of the gels, by repeated coarse grinding.
• the mixed gel is dried in a vacuum drying cabinet at 80 - 100 ° C, ground and sieved at 106 - 850 ⁇ m.
• the product has the following properties:
• the base polymer gel A is dried at 50 ° C. under vacuum in a drying cabinet, ground in a coffee grinder and finally sieved at 100-800 ⁇ m.
• the polymer gel A0 is sprayed in a Waring laboratory mixer with a crosslinking agent solution of the following composition: 2.5% by weight of 1,2-propanediol, 2.5% by weight of water, 0.2% by weight of ethylene glycol diglycidyl ether, based on polymer used.
• the moist product is then tempered at 120 ° C for 120 minutes in a circulating air drying cabinet.
• the dried product is sieved at 850 ⁇ m to remove lumps.
• Polymer A2 The basic polymer gel A is mixed with sufficient sodium hydroxide solution until a degree of neutralization of 10 mol%, based on the acrylic acid used, is reached. The partially neutralized gel is then dried, ground, sieved and post-cross-linked analogously to the production of Al.
• the basic polymer gel A is mixed with as much sodium hydroxide solution until a degree of neutralization of 20 mol%, based on the acrylic acid used, is reached.
• the partially neutralized gel is then dried, ground, sieved and post-cross-linked analogously to the production of Polymer AI.
• the basic polymer gel A is mixed with sufficient sodium hydroxide solution until a degree of neutralization of 30 mol%, based on the acrylic acid used, is achieved.
• the partially neutralized gel will then dried, ground, sieved and post-crosslinked analogously to the preparation of polymer AI.
• Polymer A5 The basic polymer gel A is mixed with sufficient sodium hydroxide solution until a degree of neutralization of 40 mol%, based on the acrylic acid used, is achieved. The partially neutralized gel is then dried, ground, sieved and post-cross-linked analogously to the production of Polymer AI.
• the basic polymer gel A is mixed with sufficient sodium hydroxide solution until a degree of neutralization of 40 mol%, based on the acrylic acid used, is achieved.
• the partially neutralized gel is then dried on a drum dryer, ground in a pin mill and sieved at 100-800 ⁇ m.
• the post-crosslinking is carried out in a Lödige mixer, a crosslinker solution of the following composition being sprayed onto 1 kg of polymer powder through a two-component nozzle: 4% by weight of methanol, 6% by weight of water, 0.2% by weight of 2 -Oxazolidinone, based on the polymer powder used.
• the moist product is then tempered at 180 ° C for 90 minutes in a circulating air drying cabinet.
• the dried product is sieved at 850 ⁇ m to remove lumps.
• the base polymer gel A is neutralized, dried and ground analogously to polymer A6.
• the powder is then sprayed with crosslinking agent solution in a Waring laboratory mixer.
• the solution is composed in such a way that the following dosage, based on the base polymer used, is achieved: 0.30% by weight of 2-oxotetrahydro-1,3-oxazine, 3% by weight of 1,2-propanediol , 7 wt .-% water, and 0.2 wt .-% boric acid.
• the moist polymer is then at 175 ° C for 60 min. dried.
• the polymer thus obtained is sprayed in a Waring laboratory mixer with 5 crosslinking agent solution having the following composition: 2.5% by weight of 1,2-propanediol, 2.5% by weight of water, 0.2% by weight of ethylene glycol digly- cidyl ether, based on the polymer used.
• the moist product is then tempered at 120 ° C for 120 minutes in a circulating air drying cabinet.
• the dried product is sieved at 850 ⁇ m to remove lumps.
• the base polymer B is sprayed in a Waring laboratory mixer with a crosslinking agent solution of the following composition: 2.5% by weight
• the base polymer B is sprayed with a crosslinking agent solution in a Waring laboratory mixer.
• the solution is composed such that the following dosage is achieved, based on the base polymer used: 0.20% by weight of glutaraldehyde, 3.0% by weight of 1,2-propanediol and 2.0% by weight of water.
• the moist polymer is then at 120 ° C for 60 min. dried and sieved at 850 ⁇ m.
• Polymer B4 The base polymer B is sprayed with crosslinker solution in a Waring laboratory mixer.
• the solution is composed in such a way that the following dosage is achieved, based on the base polymer used: 0.5% by weight of polyamidoamine resin (Resamin ® VHW 3608 from Hoechst AG), 2% by weight of 1, 2-propanediol and 3% by weight % Water.
• the moist polymer is then at 120 ° C for 6.0 min. dried and sieved at 850 ⁇ m.
• the base polymer B is sprayed with a crosslinking agent solution in a Waring laboratory mixer.
• the solution is composed such that the following dosage is achieved, 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 moist polymer is then at 180 ° C for 60 min. dried and sieved at 850 ⁇ m.
• Polymer powders produced according to Examples A0 to A8 but without surface postcrosslinking were produced with polymer powders according to Examples B and BI (without described there
• a graft copolymer based on polyethylene glycol with 5 average molecular weight 9000 (70 g) and N-vinylformamide (30 g) with a K value of 42 was diluted with 900 g of deionized water, with 20 g of a 40 wt. -% sodium bisulfite solution and 67 g of a 25 wt. -% aqueous sodium hydroxide solution stirred at 80 ° C. A further 20.1 g of 25 wt. -% NaOH solution added. The degree of hydrolysis was 81.4% of theory determined at pH 3.5 with polyelectrolyte titration. This polymer solution was desalted by means of ultrafiltration on a membrane (exclusion limit 3000 D).
• Intake capacity (30 min) [g / g]: 30.6 Intake capacity (4 h) [g / g]: 38.4 CRC (30 min) [g / g]: 11.2 AAP (0.7 psi) [ g / g]: 21.6

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• 2000
  • 2000-04-11 BR BR0009873-6A patent/BR0009873A/pt not_active Application Discontinuation
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  • 2000-04-11 WO PCT/EP2000/003220 patent/WO2000063295A1/de not_active Application Discontinuation
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• 2001
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