WO2009056436A2 - Matériau composite comprenant un polymère superabsorbant et un support et procédé de production de ce matériau par polymérisation du support en présence du polymère superabsorbant - Google Patents

Matériau composite comprenant un polymère superabsorbant et un support et procédé de production de ce matériau par polymérisation du support en présence du polymère superabsorbant Download PDF

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Publication number
WO2009056436A2
WO2009056436A2 PCT/EP2008/063713 EP2008063713W WO2009056436A2 WO 2009056436 A2 WO2009056436 A2 WO 2009056436A2 EP 2008063713 W EP2008063713 W EP 2008063713W WO 2009056436 A2 WO2009056436 A2 WO 2009056436A2
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Prior art keywords
composite material
superabsorbent polymer
elastic
dispersion
superabsorbent
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PCT/EP2008/063713
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German (de)
English (en)
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WO2009056436A3 (fr
Inventor
Hans-Jürgen QUADBECK-SEEGER
Ulrike Licht
Ernst Jügen BAUER
Timo Baumgärtner
Antje Ziemer
Armin Alteheld
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Basf Se
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Priority to DE112008002847T priority Critical patent/DE112008002847A5/de
Publication of WO2009056436A2 publication Critical patent/WO2009056436A2/fr
Publication of WO2009056436A3 publication Critical patent/WO2009056436A3/fr

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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/42—Use of materials characterised by their function or physical properties
    • A61L15/60—Liquid-swellable gel-forming materials, e.g. super-absorbents
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61L—METHODS OR APPARATUS FOR STERILISING MATERIALS OR OBJECTS IN GENERAL; DISINFECTION, STERILISATION OR DEODORISATION OF AIR; CHEMICAL ASPECTS OF BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES; MATERIALS FOR BANDAGES, DRESSINGS, ABSORBENT PADS OR SURGICAL ARTICLES
    • A61L15/00—Chemical aspects of, or use of materials for, bandages, dressings or absorbent pads
    • A61L15/16—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons
    • A61L15/22—Bandages, dressings or absorbent pads for physiological fluids such as urine or blood, e.g. sanitary towels, tampons containing macromolecular materials
    • A61L15/225—Mixtures of macromolecular compounds
    • 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
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/0061—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof characterized by the use of several polymeric components
    • 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
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • 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
    • C08J2207/00—Foams characterised by their intended use
    • C08J2207/10—Medical applications, e.g. biocompatible scaffolds
    • 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
    • C08J2361/00—Characterised by the use of condensation polymers of aldehydes or ketones; Derivatives of such polymers
    • C08J2361/20—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen
    • C08J2361/26—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds
    • C08J2361/28—Condensation polymers of aldehydes or ketones with only compounds containing hydrogen attached to nitrogen of aldehydes with heterocyclic compounds with melamine
    • 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
    • C08J2400/00—Characterised by the use of unspecified polymers
    • C08J2400/14—Water soluble or water swellable polymers, 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
    • C08J2433/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Derivatives of such polymers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L2203/00—Applications
    • C08L2203/14—Applications used for foams
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/04—Homopolymers or copolymers of esters
    • C08L33/06—Homopolymers or copolymers of esters of esters containing only carbon, hydrogen and oxygen, which oxygen atoms are present only as part of the carboxyl radical
    • C08L33/08—Homopolymers or copolymers of acrylic acid esters

Definitions

  • the present invention relates to a composite material containing at least one superabsorbent polymer and at least one elastic aminoplast foam as a carrier material, the use of such a composite material in the hygiene sector, in agriculture, in the automotive sector, in the furniture sector, as a sealing material or in the cosmetics sector, and a method for producing such composite material.
  • Superabsorbent polymers are known in the art. These are crosslinked hydrophilic polymers, in particular polymers of polymerized hydrophilic monomers, graft (co) polymers of one or more hydrophilic monomers on a suitable graft, crosslinked cellulose or starch ethers, crosslinked carboxymethylcellulose, partially crosslinked polyalkylene oxide or in aqueous products swellable natural products, such as guar derivatives, with water-absorbing polymers based on partially neutralized acrylic acid are the most common.
  • the essential properties of superabsorbents are their ability to absorb many times their own weight of aqueous liquids and not to release the liquid under some pressure.
  • the superabsorbent which is used in the form of a dry powder, transforms into a gel when liquid is taken up, with the usual absorption of water corresponding to a hydrogel.
  • the most important application of superabsorbents is the absorption of body fluids.
  • Superabsorbents are used, for example, in infant diapers, adult incontinence products or feminine hygiene products.
  • Other applications are, for example, the use as water-retaining agents in agricultural horticulture, as water storage for protection against fire, for liquid absorption in food packaging or more generally for the absorption of moisture.
  • DE 601 04 818 T2 discloses a superabsorbent article in which a solution comprising monomers, from which the superabsorbent polymers are built up, and further additives are applied to a carrier layer consisting of a fleece of synthetic fibers. After application of the monomers mentioned, the im- impregnated nonwoven exposed to conditions under which the monomers are converted to the superabsorbent polymers, so that a nonwoven fabric is obtained, which is coated on the surface and also in the interior with superabsorbent polymers.
  • DE 10034505 describes the use of open-cell foams based on melamine-formaldehyde resins in hygiene articles. It is further disclosed in this document that a sanitary article is made up of a liquid-impermeable layer, a liquid-permeable layer and an absorbent intermediate layer, the intermediate layer serving for receiving, distributing and immobilizing liquids. Furthermore, there is a storage layer of a highly swellable hydrogel, which may also be incorporated in an open-cell foam, but this foam is not specified in more detail.
  • DE 102 31 356 A1 discloses water-absorbing, foam-like polymer structures which are applied to various carrier materials, e.g. Metal, fleece or fluff are applied. The application is carried out according to this document by contacting the water-absorbing polymers and the support materials.
  • WO 2006/066752 A2 discloses polyurethane foams which contain superabsorbent polymers. These are obtained by polymerizing the precursor compounds of the polyurethane foams in the presence of the superabsorbent polymers to the corresponding polyurethanes.
  • US 2006/0252899 A1 discloses a process in which partially polymerized SAP particles are applied to a nonwoven as carrier material and polymerized there to give the finished superabsorbent polymer.
  • open-cell, flexible foams based on melamine-formaldehyde condensates can be hydrophilically modified in order to be able to absorb water-based liquids more quickly.
  • Structure with relatively large openings and channels are excellent for the absorption of aqueous body fluids, in particular for blood absorption, are suitable.
  • Foams are obtained by polymerization of (C 4 -C 4 ) -alkyl acrylates, (C 6 - Ci 6) alkyl methacrylates, (C 4 -C 2) -Alkylstyrolen as monomers, preferably styrene and ethyl styrene as comonomers, also aromatic polyvinyl compounds as crosslinking agents; optionally polyfunctional acrylates, methacrylates, acrylamides and methacrylamides and mixtures thereof as additional crosslinker substances.
  • WO-A-97/07832 US-A-5,318,554 and US-A-5,550,167 relate to the preparation of open celled foams based on HIPE emulsions and their use in sanitary articles for absorbing aqueous body fluids.
  • the open-celled foams are always used together with other components that take over storage in the hygiene article.
  • absorbent foams consist of materials known in the art for the preparation of highly swellable hydrogels (for example, crosslinked polyacrylates) in water, and subjected to the complex and costly process of freeze-drying for the purpose of producing open-cell foams become. Due to their composition, such foams require no additional absorbent components, but are expensive to produce.
  • the object of the present invention is to provide a composite material which has superabsorbent properties and, at the same time, is in a sufficiently stable form for the corresponding applications.
  • Another object of the present invention is to provide a composite material containing a carrier material capable of distributing a liquid incident on only a small portion of the material to the entire superabsorbent material.
  • the object of the present application is also to provide a method for producing such a composite material.
  • a composite material comprising at least one superabsorbent polymer and at least one elastic aminoplast foam as support material.
  • the objects of the present invention are achieved by sanitary products, sealing materials, insulating materials, desiccants, water reservoirs, packaging and artificial plant substrates containing such a composite material by the use of this composite material, as well as by a process for producing a composite material at least one superabsorbent polymer and at least one elastic aminoplast foam as support material comprising the steps:
  • step (B) adding at least one superabsorbent polymer to the aqueous solution or dispersion of step (A), and
  • Step (B) to obtain the composite material by heating.
  • Step (A) of the process according to the invention comprises the provision of an aqueous solution or dispersion which contains precursor compounds of the at least one elastic aminoplast foam and optionally further additives.
  • Suitable carrier materials in the process according to the invention may generally be any of the elastic aminoplast foams known to those skilled in the art, i. foamed elastic aminoplast resins are used.
  • aminoplast resins is meant generally polycondensation products of carbonyl compounds, especially formaldehyde, and compounds containing NH groups, e.g. Urea, melamine, urethanes, cyanamide and dicyandiamide, aromatic amines and sulfonamides.
  • Aminoplast resins generally have relatively low degrees of polymerization. When used as thermosets, these are cured, see Römpp, Chemielexikon, 9th edition, p. 159.
  • the elastic aminoplast foam is a foamed melamine / formaldehyde resin whose molar ratio of melamine to formaldehyde is particularly preferably between 1, 0: 1, 0 and 1, 0: 1, 9.
  • melamine / formaldehyde condensation products may contain up to 50% by weight, preferably up to 20% by weight, of other thermosets and, in addition to formaldehyde, up to 50% by weight, preferably up to 20% by weight, of other aldehydes.
  • thermoset plasticizers are: alkyl- and aryl-substituted melamine, urea, urethanes, carboxylic acid amides, dicy- andiamide, guanidine, sulfuryl amide, sulfonic acid amides, aliphatic amines, glycols, phenol and its derivatives.
  • suitable aldehydes include acetaldehyde, trimethylolacetaldehyde, acrolein, benzaldehyde, furfurol, glyoxal, glutaraldehyde, phthalaldehyde and terephthalaldehyde.
  • the molar ratio of melamine to formaldehyde in the aminoplast resin is generally within wide limits between 1, 0: 1, 0 and 1, 0: 5.0. In a preferred embodiment, the molar ratio of melamine to formaldehyde is greater than 1, 0: 2.0, more preferably between 1, 0: 1, 0 and 1, 0: 1, 9, most preferably between 1, 0: 1 , 3 and 1, 0: 1, 8.
  • Said melamine / formaldehyde resin may contain condensed sulfite groups, which can be done for example by adding 1 to 20 wt .-% sodium bisulfite to the solution provided in step (A) of the method according to the invention.
  • the sulfite group content of the melamine / formaldehyde resin is below 1%, more preferably below 0.1%, and most preferably at 0%.
  • the solution used in step (A) of the process according to the invention contains a precondensate of melamine and formaldehyde in the abovementioned ratios.
  • This precondensate is prepared in a separate step under basic conditions. Corresponding methods are known to the person skilled in the art.
  • the solution or dispersion used in step (A) of the process according to the invention contains in step (A) as further additives at least one blowing agent, at least one emulsifier and at least one curing agent.
  • a composite material is produced which has an open-cell elastic foam based on melamine / formaldehyde condensation products as support material.
  • a foam in the process according to the invention from the melamine / formaldehyde resin solution provided in step (A) of the process according to the invention, it must contain a blowing agent, the amount being governed by the desired density of the foam.
  • a blowing agent the amount being governed by the desired density of the foam.
  • both physical and chemical blowing agents can be used in the production of the foam. Suitable physical blowing agents are, for example, hydrocarbons, halogenated, in particular fluorinated hydrocarbons, alcohols, ethers, ketones and esters in liquid form or air and CO 2 as gases.
  • chemical blowing agents come z.
  • the aqueous solution or dispersion to be provided in step (A) of the process according to the invention is between 1 and 40% by weight, based on the resin, of a physical blowing agent having a boiling point 0 and 80 0 C added.
  • a physical blowing agent having a boiling point 0 and 80 0 C added.
  • pentane it is preferably 5 to 15 wt .-%.
  • an emulsifier or an emulsifier mixture is preferably used according to the invention.
  • Anionic, cationic and nonionic surfactants and mixtures thereof can be used as the emulsifier.
  • Suitable anionic surfactants are diphenylene oxide sulfonates, alkane and alkylbenzenesulfonates, alkylnaphthalenesulfonates, olefinsulfonates, alkyl ether sulfonates, fatty alcohol sulfates, ether sulfates, alpha-sulfofatty acid esters, acylaminoalkanesulfonates, acyl isethionates, alkylethercarboxylates, N-acylsarcosinates, alkyl and alkyl ether phosphates.
  • alkylphenol polyglycol ethers fatty alcohol polyglycol ethers, fatty acid polyglycol ethers, fatty acid alkanolamides, EO / PO block copolymers, amine oxides, glycerol fatty acid esters, sorbitan esters and alkyl polyglucosides can be used.
  • the cationic emulsifiers used are trialkylammonium salts, alkylbenzyldimethylammonium salts and alkylpyridinium salts.
  • the emulsifiers or the emulsifier mixtures are preferably added in amounts of from 0.2 to 5% by weight, based on the resin.
  • Preferred hardeners used in the solution to be prepared in step (A) of the process according to the invention are acidic compounds which catalyze the further condensation of the benzamine resin.
  • the amounts are from 0.01 to 20 wt .-%, preferably 0.05 to 5 wt .-%, based on the resin.
  • inorganic and organic acids e.g. Hydrochloric acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, oxalic acid, toluenesulfonic acids, amidosulfonic acids and acid anhydrides.
  • the aqueous solution or dispersion to be provided in step (A) of the process according to the invention for the production of the composite material is preferably free of further additives. However, for some purposes, it may be convenient to more than 20% by weight, preferably less than 10% by weight, based on the resin, more commonly Add additives such as dyes, flame retardants, UV stabilizers, agents to reduce the burn gas toxicity or to promote the charring.
  • Liquids such as water
  • Suitable water repellents are, for example, silicones, paraffins, silicone and fluorosurfactants.
  • solvents for the aqueous solution or dispersion used according to the invention it is possible to use all mixtures of water with, preferably polar, solvents known to the person skilled in the art.
  • Suitable solvents which are present in admixture with water are, for example, aliphatic alcohols having 1 to 8 carbon atoms, for example methanol, ethanol, n-propanol, isopropanol, or mixtures thereof.
  • water is used as the solvent.
  • the concentration of the precursor compounds of the at least one aminoplast resin in the aqueous solution or dispersion provided in step (A) of the process according to the invention can be within wide limits of 55 to 85% by weight, preferably 63 to 80% by weight, in each case based on the solution or dispersion.
  • step (A) of the process according to the invention can be carried out by all methods known to the person skilled in the art, for example by submitting the solvent and adding the individual components.
  • the mixing can preferably be carried out in an extruder.
  • Providing and mixing can be carried out at any suitable pressure from 0.1 bar to 10 bar, preferably at atmospheric pressure and at any suitable temperature between 0 and 80 0 C, preferably at room temperature.
  • the individual ingredients are mixed homogeneously, and the propellant is pressed under pressure.
  • Step (A) of the process according to the invention can be carried out continuously and batchwise.
  • Step (B) of the process of the invention comprises adding at least one superabsorbent polymer to the aqueous solution or dispersion of step (A).
  • the superabsorbent contained in the composite material according to the invention is a common superabsorber, which can absorb a multiple of its own weight of water and retain it under some pressure.
  • the superabsorbent has a CRC ("Centrifuge Retention Capacity", measuring method see below) of at least 5 g / g, preferably at least 10 g / g and in a particularly preferred form at least 15 g / g
  • the superabsorbent is a cross-linked polymer
  • a "superabsorber" can also be a mixture of materially different individual superabsorbers, it depends less on the material composition than on the superabsorbent properties.
  • the at least one superabsorbent polymer is a homo- or copolymer containing unsaturated mono- or dicarboxylic acids.
  • Synthetic superabsorbents are obtained, for example, by polymerization of a monomer solution containing
  • Suitable monomers a) are, for example, ethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, or their derivatives, such as acrylamide, methacrylamide, acrylic esters and methacrylic esters, or salts thereof, for example alkali metal salts of acrylic acid, methacrylic acid, maleic acid, fumaric acid and itaconic acid, preferably the lithium, sodium or potassium salts.
  • Particularly preferred monomers are acrylic acid and methacrylic acid and their sodium salts. Very particular preference is given to acrylic acid and the sodium salt of acrylic acid.
  • Preferred hydroquinone half ethers are hydroquinone monomethyl ether (MEHQ) and / or tocopherols.
  • Tocopherol is understood as meaning compounds of the following formula (I)
  • R 1 is hydrogen or methyl
  • R 2 is hydrogen or methyl
  • R 3 is hydrogen or methyl
  • R 4 is hydrogen or an acid radical having 1 to 20 carbon atoms.
  • Preferred radicals for R 4 are acetyl, ascorbyl, succinyl, nicotinyl and other physiologically acceptable carboxylic acids.
  • the carboxylic acids can be mono-, di- or tricarboxylic acids.
  • R 4 is particularly preferably hydrogen or acetyl. Especially preferred is RRR-alpha-tocopherol.
  • the monomer solution for the preparation of the superabsorbent polymer preferably contains at most 130 ppm by weight, more preferably at most 70 ppm by weight, preferably at least 10 ppm by weight, particularly preferably at least 30 ppm by weight, in particular by 50 ppm by weight, Hydroquinone, in each case based on acrylic acid, wherein acrylic acid salts are taken into account as acrylic acid.
  • acrylic acid having a corresponding content of hydroquinone half-ether can be used.
  • the crosslinkers b) are compounds having at least two polymerizable groups which can be incorporated in the polymer network by free-radical polymerization.
  • Suitable crosslinkers b) are, for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, allyl methacrylate, trimethylolpropane triacrylate, triallylamine, tetraallyloxyethane, as described in EP 530 438 A1, di- and triacrylates, as in EP 547 847 A1, EP 559 476 A1, EP 632 068 A1, WO 93 / 21,237 A1, WO 03/104 299 A1, WO 03/104 300 A1, WO 03/104 301 A1 and DE 103 31 450 A1, mixed acrylates which, in addition to acrylate groups, contain further ethylenically unsaturated groups, as described in DE 103 31 456 A1 and WO 04/013 064 A2, or crosslinking mixtures, as described, for example,
  • Suitable crosslinkers b) are, in particular, N, N'-methylenebisacrylamide and N, N'-methylenebismethacrylamide, esters of unsaturated monocarboxylic or polycarboxylic acids of polyols, such as diacrylate or triacrylate, for example butanediol or ethylene glycol diacrylate or methacrylate, and trimethylolpropane triacrylate and allyl compounds, such as allyl (meth) acrylate, triallyl cyanurate, maleic acid diallyl esters, polyallyl esters, tetraallyl oxyethane, triallylamine, tetraallylethylenediamine, allyl esters of phosphoric acid and vinylphosphonic acid derivatives, as described, for example, in EP 343 427 A2.
  • crosslinkers b) are pentaerythritol di-, pentaerythritol tri- and pentaerythritol tetraallyl ethers, polyethylene glycol diallyl ethers, ethylene glycol diallyl ether, glycerol di- and glycerol triallyl ethers, polyallyl ethers based on sorbitol, and ethoxylated variants thereof.
  • Useful in the process according to the invention are di (meth) acrylates of polyethylene glycols, wherein the polyethylene glycol used has a molecular weight between 300 and 1000.
  • crosslinkers b) are di- and triacrylates of 3 to 15-fold ethoxylated glycerol, of 3 to 15-fold ethoxylated trimethylolpropane, of 3 to 15-fold ethoxylated trimethylolethane, in particular di- and triacrylates of 2-membered to 6-fold ethoxylated glycerol or trimethylolpropane, the 3-fold propoxylated glycerol or trimethylolpropane, and the 3-fold mixed ethoxylated or propoxylated glycerol or trimethylolpropane, 15-ethoxylated glycerol or trimethylolpropane, as well as 40-times ethoxylated glycerol, trimethylolethane or trimethylolpropane.
  • Very particularly preferred crosslinkers b) are the polyethoxylated and / or propoxylated glycerols esterified with acrylic acid or methacrylic acid to form di- or triacrylates, as described, for example, in WO 03/104 301 A1.
  • Particularly advantageous are di- and / or triacrylates of 3- to 10-fold ethoxylated glycerol.
  • diacrylates or triacrylates of 1 to 5 times ethoxylated and / or propoxylated glycerol.
  • Most preferred are the triacrylates of 3 to 5 times ethoxylated and / or propoxylated glycerol.
  • acrylamide, methacrylamide, crotonic acid amide, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, diethylaminopropene, and ethylenically unsaturated monomers c) copolymerizable with the monomers a) are pyl acrylate, dimethylaminobutyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, dimethylaminoneopentyl acrylate and dimethylaminoneopentyl methacrylate.
  • polyvinyl alcohol polyvinylpyrrolidone, starch, starch derivatives, polyglycols, formally wholly or partially from Vinylaminmonomeren built polymers such as partially or fully hydrolyzed polyvinylamide (so-called "polyvinylamine”) or polyacrylic acids, preferably polyvinyl alcohol and starch, are used.
  • polyvinylamine partially or fully hydrolyzed polyvinylamide
  • polyacrylic acids preferably polyvinyl alcohol and starch
  • Suitable polymerization regulators are, for example, thio compounds, such as thioglycolic acid, mercaptoalcohols, e.g. 2-mercaptoethanol, mercaptopropanol and mercaptobutanol, dodecylmercaptan, formic acid, ammonia and amines, e.g. As ethanolamine, diethanolamine, triethanolamine, triethylamine, morpholine and piperidine.
  • thio compounds such as thioglycolic acid, mercaptoalcohols, e.g. 2-mercaptoethanol, mercaptopropanol and mercaptobutanol, dodecylmercaptan, formic acid, ammonia and amines, e.g. As ethanolamine, diethanolamine, triethanolamine, triethylamine, morpholine and piperidine.
  • the monomers (a), (b) and optionally (c) are, optionally in the presence of water-soluble polymers d), in 20 to 80, preferably 20 to 50, in particular 30 to 45 wt .-% aqueous solution in the presence of polymerization initiators co-polymerized with one another (co).
  • polymerization initiators all the compounds decomposing into the radical under the polymerization conditions can be used, e.g. Peroxides, hydroperoxides, hydrogen peroxide, persulfates, azo compounds and the so-called redox initiators. Preference is given to the use of water-soluble initiators. In some cases, it is advantageous to use mixtures of different polymerization initiators, for. B.
  • 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 perohexanoate, tert-butyl perisobutyrate, tert-butyl per 2-ethylhexanoate, tert-butyl perisononanoate, tert.
  • Suitable polymerization initiators are azo initiators, e.g. 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N-dimethylene) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutyronitrile and 4,4'-azobis (4 -cyanovalerianklare).
  • azo initiators e.g. 2,2'-azobis (2-amidinopropane) dihydrochloride, 2,2'-azobis (N, N-dimethylene) isobutyramidine dihydrochloride, 2- (carbamoylazo) isobutyronitrile and 4,4'-azobis (4 -cyanovalerianklare).
  • the polymerization initiators mentioned are used in conventional amounts, for. B. in amounts of 0.01 to 5, preferably 0.1 to 2 mol%, based on the monomers to be polymerized.
  • the redox initiators contain as oxidizing component at least one of the abovementioned per compounds and a reducing component, for example
  • Ascorbic acid glucose, sorbose, ammonium or alkali metal hydrosulfite, sulfite, thiosulfate, hyposulfite, pyrosulfite or sulfide, metal salts such as ferrous ions or silver ions or sodium hydroxymethylsulfoxylate.
  • Ascorbic acid or sodium pyrosulfite is preferably used. Based on the amount of monomers used in the polymerization is used 1 ⁇ 10 "5 to 1 mol% of the reducing component of the redox initiator and 1 ⁇ 10 " 5 to 5 mol% of the oxidizing component.
  • the oxidizing component or in addition one can also use one or more water-soluble azo initiators.
  • a redox initiator comprising hydrogen peroxide, sodium peroxodisulfate and ascorbic acid.
  • these components are used in the concentrations 1 ⁇ 10 "2 mol% hydrogen peroxide, 0.084 mol% fat and 2.5 Natriumperoxodisul- ⁇ 10" used 3 mol% based on the monomers ascorbic acid.
  • the aqueous monomer solution may contain the initiator dissolved or dispersed. However, the initiators can also be fed to the polymerization reactor separately from the monomer solution.
  • the polymerization inhibitors require dissolved oxygen for optimum performance.
  • the polymerization inhibitors may be prepared by inerting, i. Flow through with an inert gas, preferably nitrogen, to be freed of dissolved oxygen. This is done by means of inert gas, which can be introduced in cocurrent, countercurrent or intermediate inlet angles. Good mixing can be achieved, for example, with nozzles, static or dynamic mixers or bubble columns.
  • the oxygen content of the monomer solution before polymerization is reduced to less than 1 ppm by weight, more preferably less than 0.5 ppm by weight.
  • the monomer solution is optionally passed through the reactor with an inert gas stream.
  • Superabsorbents are typically obtained by polymerization of an aqueous monomer solution and optionally subsequent comminution of the hydrogel. Suitable preparation methods are described in the literature. Superabsorbers are obtained, for example, by: Gel polymerization in the batch process or tube reactor and subsequent comminution in the meat grinder, extruder or kneader, as described for example in EP 445 619 A2 and DE 19 846 413 A1;
  • the reaction is preferably carried out in a kneader or on a belt reactor.
  • the preferred production process for superabsorbents which is currently preferred for economic reasons, is continuous gel polymerization.
  • a monomer mixture is first prepared by adding the neutralizing agent, optional comonomers and / or further auxiliaries to the acrylic acid solution in temporally and / or spatially separate addition sequence, and the mixture is then transferred to the reactor, or is already introduced into the reactor.
  • the last addition is the metering of the initiator system to start the polymerization.
  • the reaction proceeds to the polymer gel (i.e., the polymer swollen to the gel in the solvent of the polymerization - usually water -) which, in the case of stirred polymerization, is already comminuted in advance.
  • the polymer gel is then dried, if necessary, also broken, ground and sieved and transferred for further surface treatment.
  • the acid groups of the hydrogels obtained are usually partially neutralized, generally at least 25 mol%, preferably at least 27 mol% and more preferably at least 40 mol%, and generally at most 85 mol%, preferably at most 80 mol%. % and in a particularly preferred form at most 75 mol%, to which the customary neutralizing agents can be used, preferably alkali metal hydroxides, alkali metal oxides, alkali metal carbonates or alkali metal bicarbonates and mixtures thereof.
  • alkali metal salts Ammonium salts can also be used.
  • Sodium and potassium are particularly preferred as alkali metals, but most preferably sodium hydroxide, sodium carbonate or sodium bicarbonate and mixtures thereof.
  • the neutralization is achieved by mixing in the neutralizing agent as an aqueous solution or preferably also as a solid.
  • sodium hydroxide with a water content well below 50 wt .-% may be present as a waxy mass with a melting point above 23 ° C. In this case, a dosage as general cargo or melt at elevated temperature is possible.
  • the neutralization can be carried out after the polymerization at the hydrogel stage. However, it is also possible to carry out the neutralization to the desired degree of neutralization completely or partially before the polymerization. In the case of partial neutralization before the polymerization, at least 10 mol%, preferably at least 15 mol%, and generally at most 40 mol%, preferably at most 30 mol%, and more preferably at most 25 mol% of the acid groups are generally included in the neutralized prior to polymerization by adding a part of the neutralizing agent is already added to the monomer solution.
  • the desired final degree of neutralization is in this case set only towards the end or after the polymerization, preferably at the stage of the hydrogel before it is dried.
  • the monomer solution is neutralized by mixing in the neutralizing agent.
  • the hydrogel can be mechanically comminuted in the neutralization, for example by means of a meat grinder or similar apparatus for comminuting gel-like masses, wherein the neutralizing agent is sprayed, sprinkled or poured over and then mixed thoroughly.
  • the gel mass obtained can be comminuted several times for homogenization, for example with the help of a meat grinder.
  • the monomer solution is adjusted to the desired final degree of neutralization prior to polymerization by addition of the neutralizing agent.
  • the gels obtained from the polymerization are optionally for some time, for example at least 30 minutes, preferably at least 60 minutes and more preferably at least 90 minutes and generally at most 12 hours, preferably at most 8 hours and in a particularly preferred form at most 6 hours a temperature of generally at least 50 0 C and preferably at least 70 0 C and generally held at most 130 0 C and preferably at most 100 0 C, whereby their properties can often be improved.
  • the neutralized hydrogel is then dried with a belt or drum dryer until the residual moisture content is preferably below 15 wt .-%, in particular below 10% by weight, the water content being determined according to the test method No. 430.2-02 "Moisture Content" recommended by the EDANA (European Disposables and Nonwovens Association).
  • the dry superabsorbent thus contains up to 15% by weight of moisture, preferably at most 10% by weight.
  • % lies.
  • Particularly advantageous is the ventilation of the dryer with nitrogen or other non-oxidizing inert gas.
  • nitrogen or other non-oxidizing inert gas it is also possible simply to lower only the partial pressure of the oxygen during the drying in order to prevent oxidative yellowing processes.
  • sufficient ventilation and removal of the water vapor also leads to an acceptable product.
  • Advantageous in terms of color and product quality is usually the shortest possible drying time.
  • the dried hydrogel which is no longer a gel, even if it is often referred to as such, but a dry polymer with superabsorbent properties, which falls under the term "superabsorbent", is preferably ground and sieved, milling mills, pin mills,
  • the particle size of the sieved, dry hydrogel is preferably below 1000 .mu.m, more preferably below 900 .mu.m, most preferably below 850 .mu.m, and preferably above 80 .mu.m, more preferably above 90 .mu.m, most preferably over 100 ⁇ m.
  • the superabsorbent polymers prepared in this way are usually referred to as "base polymers” and are preferably subsequently surface-postcrosslinked Surface postcrosslinking can be carried out in a manner known per se with dried, ground and screened polymer particles react under crosslinking, usually in the form of a solution applied to the surface of the base polymer particles.
  • Di- or polyepoxides for example di- or polyglycidyl compounds, such as phosphonic acid diglycidyl esters, ethylene glycol diglycidyl ethers or bischlorohydrin ethers of polyalkylene glycols,
  • Polyaziridines compounds containing aziridine units and 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 having an average molecular weight Mw of 200 to 10,000, di- and polyglycerol, pentaerythritol, sorbitol, the ethoxylates of these polyols and their
  • Esters with 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- and poly-N-methylol compounds such as, for example, methylenebis (N-methylolmethacrylamide) or melamine-formaldehyde resins,
  • acid catalysts such as p-toluenesulfonic acid, phosphoric acid, boric acid or ammonium dihydrogen phosphate may be added.
  • Particularly suitable postcrosslinkers are di- or polyglycidyl compounds such as ethylene glycol diglycidyl ether, the reaction products of polyamidoamines with epichlorohydrin, 2-oxazolidinone and N-hydroxyethyl-2-oxazolidinone.
  • the surface postcrosslinking is usually carried out in such a way that a solution of the surface postcrosslinker, often only Called postcrosslinker, is sprayed onto the hydrogel or the dry base polymer powder.
  • the solvent used for the surface postcrosslinker is a customary suitable solvent, for example water, alcohols, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and mixtures thereof. Particularly preferred are water and water / alcohol mixtures such as water / methanol, water / 1, 2-propanediol and water / 1, 3-propanediol.
  • the spraying of a solution of the postcrosslinker is preferably carried out in mixers with agitated mixing tools, such as screw mixers, paddle mixers, disk mixers, ploughshare mixers and paddle mixers.
  • agitated mixing tools such as screw mixers, paddle mixers, disk mixers, ploughshare mixers and paddle mixers.
  • Vertical mixers are particularly preferred, plowshare mixers and paddle mixers are very particularly preferred.
  • Suitable and known mixers include for example Lödige ® - sawn pex ® - Nauta ® - Processall® ® - and Schugi ® mixer. Very particular preference high speed mixer lizer for example of the Schugi Flexomix ® or Turbo ®, are used.
  • the crosslinker solution may optionally follow a temperature treatment step, essentially for carrying out the surface postcrosslinking reaction, yet usually only referred to as "drying", followed, preferably in a downstream heated mixer (“dryer"), at a temperature of generally at least 50 0 C, preferably at least 80 0 C and in a particularly preferred form at least 90 0 C and generally at most 250 0 C, preferably at most 200 0 C and in a particularly preferred form at most 150 0 C.
  • dryer a downstream heated mixer
  • the average residence time, ie the averaged Dwell time of the individual superabsorbent particles of the superabsorbent to be treated in the dryer is generally at least 1 minute, preferably at least 3 minutes and more preferably at least 5 minutes and generally at most 6 hours, preferably at most 2 hours and most preferably at most 1 hour. In this case, not only the actual drying but also any existing cleavage products and solvent components are removed.
  • the thermal drying is carried out in conventional dryers, such as tray dryers, rotary kilns or heatable screws, preferably in contact dryers.
  • dryers in which the product is moved ie heated mixers, particularly preferably paddle dryers, most preferably disc dryers.
  • Suitable dryers include for example Bepex dryers and ® -T N ara ® -T Rockner. Moreover, fluidized bed dryers can also be used. The drying can also be done in the mixer itself, by heating the jacket or blowing a preheated gas such as air. However, it is also possible, for example, to carry out azeotropic distillation as a drying process. drive to be used. The crosslinking reaction can take place both before and during drying.
  • the hydrophilicity of the particle surface of the base polymers is additionally modified by the formation of complexes.
  • the formation of the complexes on the outer shell of the particles is carried out by spraying solutions of divalent or polyvalent cations, wherein the cations can react with the acid groups of the polymer to form complexes.
  • divalent or polyvalent cations are polymers which are formally wholly or partially composed of vinylamine monomers, such as partially or completely hydrolyzed polyvinylamide (so-called "polyvinylamine”), whose amine groups are always partially protonated to ammonium groups, even at very high pH values, or metal cations such as 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 4+ , 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 + , and particularly preferred metal cations are Al 3+ , Ti 4+ and Zr 4 + .
  • the metal cations can be used both alone and in
  • aluminum sulfate is used.
  • solvents for the metal salts water, alcohols, dimethylformamide (DMF), dimethyl sulfoxide (DMSO) and mixtures of these components can be used.
  • water and water / alcohol mixtures such as water / methanol, water / 1, 2-propanediol and water / 1, 3-propanediol.
  • the treatment of the base polymer with solution of a di- or polyvalent cation is carried out in the same way as with surface postcrosslinkers, including the optional drying step.
  • Surface postcrosslinker and polyvalent cation can be sprayed in a common solution or as separate solutions.
  • the spraying of the metal salt solution onto the superabsorbent particles can be carried out both before and after the surface postcrosslinking.
  • the spraying of the metal salt solution is carried out in the same step by spraying the crosslinker solution, wherein both solutions are sprayed separately successively or simultaneously via two nozzles, or crosslinker and metal salt solution can be sprayed together via a nozzle.
  • a drying step is carried out after the surface postcrosslinking and / or treatment with complexing agent, it is advantageous, but not absolutely necessary, to cool the product after drying.
  • the cooling can carried out continuously or discontinuously, for example, the product is continuously conveyed to a dryer downstream cooler.
  • Any apparatus known for removing heat from powdered solids may be used for this purpose, in particular any apparatus mentioned above as a drying apparatus, unless it is supplied with a heating medium but with a cooling medium, such as cooling water, so that over the walls and depending on the construction no heat is also introduced into the superabsorber via the stirring elements or other heat exchange surfaces, but is removed therefrom.
  • Bepex ® coolers the use of coolers in which the product is moved, that is, cooled mixers, examples of playing paddle coolers, disk coolers or paddle coolers, for example Nara ® is preferred.
  • the superabsorber can also be cooled in the fluidized bed by blowing in a cooled gas such as cold air. The conditions of the cooling are adjusted so that a superabsorbent is obtained with the temperature desired for further processing.
  • an average residence time in the condenser of generally at least 1 minute, preferably at least 3 minutes and more preferably at least 5 minutes and generally at most 6 hours, preferably at most 2 hours and most preferably at most 1 hour is set and Cooling capacity so that the product obtained has a temperature of generally at least 0 0 C, preferably at least 10 0 C and more preferably at least 20 0 C and generally at most 100 0 C, preferably at most 80 0 C and in a particularly preferred form has at most 60 0 C.
  • a further modification of the superabsorbents by admixing finely divided inorganic solids, such as silica, alumina, titanium dioxide and iron (II) oxide take place, whereby the effects of the surface treatment are further enhanced.
  • finely divided inorganic solids such as silica, alumina, titanium dioxide and iron (II) oxide
  • admixture of hydrophilic silica or alumina with an average size of the primary particles of 4 to 50 nm and a specific surface area of 50-450 m 2 / g.
  • the admixture of finely divided inorganic solids is preferably carried out after the surface modification by crosslinking / complex formation, but can also be carried out before or during these surface modifications.
  • the superabsorbent is provided with other common additives and adjuvants that affect storage or handling properties. Examples include stains, opaque additives to improve the visibility of swollen gel, which is desirable in some applications, additives to improve the flow behavior of the powder, surfactants or the like.
  • the dedusting or dust binder is added to the superabsorbent.
  • Dedusting or dust-binding agents are known, for example, polyether glycols such as polyethylene glycol having a molecular weight of 400 to 20,000 g / mol, polyols such as glycerol, sorbitol, Neopentyl glycol or trimethylolpropane, which are optionally also 7 to 20-fold ethoxylated used. Even a finite water content of the superabsorbent can be adjusted by adding water, if desired.
  • the solids, additives and auxiliaries can each be added in separate process steps, but usually the most convenient method is to add them to the superabsorber in the cooler, for example by spraying a solution or adding it in finely divided solid or in liquid form.
  • the surface postcrosslinked superabsorbent is optionally ground and / or sieved in the usual way. Milling is typically not required here, but most often, the setting of the desired particle size distribution of the product, the screening of formed agglomerates or fine grain is appropriate. Agglomerates and fines are either discarded or preferably recycled to the process in a known manner and at a suitable location; Agglomerates after comminution.
  • the particle size of the superabsorbent particles is preferably at most 1000 .mu.m, more preferably at most 900 .mu.m, most preferably at most 850 .mu.m, and preferably at least 80 .mu.m, more preferably at least 90 .mu.m, most preferably at least 100 .mu.m.
  • Typical sieve cuts are, for example, 106 to 850 ⁇ m or 150 to 850 ⁇ m.
  • the superabsorbent polymer used according to the invention can contain at least one odor inhibitor, for example a keto acid, organic acids, urease inhibitors or mixtures thereof, for avoiding or reducing unpleasant odors, for example after contact with body fluids.
  • at least one odor inhibitor for example a keto acid, organic acids, urease inhibitors or mixtures thereof, for avoiding or reducing unpleasant odors, for example after contact with body fluids.
  • Keto acids are a subgroup of the oxocarboxylic acids, namely the carboxylic acids which contain a ketone group in addition to a carboxy group.
  • the keto acid which may optionally be present in the superabsorbent polymer which can be used according to the invention has the general formula R 5 -C (O) -R 6 -COOH, where R 6 may be omitted and preferably also omitted.
  • the composition according to the invention therefore preferably contains superabsorbent and at least one keto acid of the general formula R 5 -CO-COOH, ie an alpha-keto acid or 2-oxo-carboxylic acid.
  • R 5 is a linear, branched or cyclic organic radical which is optionally substituted.
  • R 5 is for example a d- to C 30 -alkyl radical, preferably a C 2 - to C 0 -
  • Alkyl radical particularly preferably a C 3 - to C 4 -alkyl radical.
  • d- to Ci 0 - Alkyl radicals are methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, n-hexyl, isohexyl, n-heptyl, isoheptyl, n-octyl, isooctyl , n-nonyl, isononyl, n-decyl and isodecyl.
  • Very particularly preferred alkyl radicals are n-propyl and n-butyl. This alkyl radical is optionally substituted by one or more functional groups, in particular one or more hydroxy and / or carboxy groups.
  • R 6 if present, is an organic group having two attachment sites, for example a - (CH 2 ) n - group, where n is generally a number from 1 to 4.
  • the group may be linear, branched or cyclic and optionally substituted.
  • the keto acid is 2-oxo-L-gulonic acid (the L-enantiomer of 2-oxo-3,4,5,6-tetrahydroxihexanoic acid) and / or 2-oxo-glutaric acid (2-oxo-pentane). 1, 5-diacid).
  • the optionally present keto acid can be applied by:
  • the amount of the keto acid in the superabsorbent based on the amount of superabsorbent is generally at least 0.005 wt%, preferably at least 0.01 wt%, more preferably at least 0.1 wt%, and most preferably Form at least 0.5 wt .-% and generally at most 15 wt .-%, preferably at most 12 wt .-% and in a particularly preferred form at most 10 wt .-%.
  • this amount is 1 wt .-%, 2 wt .-%, 3 wt .-%, 4 wt .-%, 5 wt .-%, 6 wt .-%, 7 wt .-%, 8 wt. % or 9 wt .-%, each based on the amount of superabsorbent.
  • the superabsorbent polymer may be added to the solution or dispersion of step (A) by any means known to those skilled in the art.
  • the superabsorbent may be added as a solid, in solution or dispersion. Suitable solvents are those mentioned with respect to the solution or dispersion in step (A).
  • the superabsorbent is preferably added in substance to the solution or dispersion.
  • the addition in step (B) of the process according to the invention can be carried out at any suitable temperature, for example 0 to 100 ° C., preferably room temperature.
  • the addition can be carried out at any suitable pressure, for example 0.5 to 10 bar, preferably atmospheric pressure or slightly elevated atmospheric pressure.
  • the resulting mixture is preferably mixed before the aminoplast resin is polymerized in step (C).
  • the mixing can be carried out by any method known to the person skilled in the art, for example with an extruder.
  • the superabsorbent is in a preferred embodiment in an amount of 0.01 to 50 wt .-%, particularly preferably 0.01 to 20 wt .-%, most preferably 0.1 to 15 wt .-%, each based on the entire composite material, added.
  • Step (C) of the process of the invention comprises polymerizing the precursor compounds of the at least one aminoplast resin in the solution or dispersion of step (B) to obtain the composite material by heating.
  • a melamine / formaldehyde foam is present as the carrier material, then in a preferred embodiment in the inventive step (C) the present solution or dispersion is foamed simultaneously with the polymerization.
  • step (C) Since the polymerization in step (C) is carried out in the solution of step (B), the elastic amine resin is formed in the presence of the at least one superabsorbent polymer. This makes it possible to achieve in the composite material according to the invention a very uniform distribution of the at least one superabsorbent polymer in the foamed material acting as support material based on the aminoplast resin.
  • step (C) of the process according to the invention for polymerizing and optionally foaming the support material can in principle - as described in EP-B17671 - be made by hot gases or high frequency irradiation.
  • the required heating is preferably carried out by ultra-high frequency irradiation according to EP-B 37470.
  • this dielectric radiation with microwaves in the frequency range from 0.2 GHz to 100 GHz.
  • frequencies of 0.915, 2.45 and 5.8 GHz are available, with 2.45 GHz being particularly preferred.
  • Radiation source for dielectric radiation is the magnetron, which can be irradiated simultaneously with several magnetrons. Care must be taken to ensure that the field distribution during irradiation is as homogeneous as possible in order to obtain a uniformly polymerized and optionally foamed carrier material.
  • the irradiation is carried out so that the power consumption of the solution or dispersion between 5 and 200, preferably between 9 and 120 KW, based on 1 kg of water in the solution or dispersion. If the recorded power is lower, then no more foaming takes place and the mixture only hardens. If you work within the preferred range, the mixture foams faster, the greater the power consumption. Above about 200KW per kg of water, the foaming speed does not increase significantly.
  • the present in the solution or dispersion MeI- amine / formaldehyde precondensates are polymerized.
  • the optional blowing agent is chemically decomposed, thereby generating a gas, for example CO 2 , or the blowing agent evaporates at the temperature and thus generates a gas.
  • the gas thus produced foams the composite material containing aminoplast resin and superabsorbent polymer:
  • the composite material according to the invention is subjected to a temperature treatment in a preferred embodiment. It is heated for 1 to 180 minutes, preferably for 5 to 60 minutes at temperatures of 50 to 200 0 C, preferably 80 to 120 0 C, wherein water, blowing agent and formaldehyde are largely removed.
  • the composite material produced according to the invention has a density of 5 to 50 g * 1 " , preferably 6 to 30 g * 1 " .
  • the present invention also relates to a composite material comprising at least one superabsorbent polymer on an aminoplast resin as support material.
  • this composite material can be produced by the process according to the invention.
  • the composite materials according to the invention preferably contain 0.1-0.9 g of SAP (dry) / liter of foam.
  • the at least one superabsorbent polymer is preferably present in an amount of from 0.01 to 50% by weight, particularly preferably from 0.01 to 20% by weight, very particularly preferably from 0.1 to 15% by weight, each related to the composite material, before.
  • the at least one support material is preferably in an amount of 50 to 99.99 wt .-%, more preferably 80 to 99.99 wt .-%, most preferably 85 to 99.9 wt .-%, respectively based on the composite material.
  • the amount of superabsorber is just so great that in the swollen state, the pores of the carrier material are completely filled.
  • the composite materials according to the invention are distinguished by a very uniform distribution of the superabsorbent in the carrier material. Furthermore, no additional process step for the introduction of the superabsorbent in the carrier material after its production is necessary. If fully swollen superabsorbers are used in the process according to the invention, it is ensured that the pore volume corresponds to the volume of the swollen superabsorber, and thereby an optimum pore size is achieved.
  • the composite material according to the invention is capable of absorbing large quantities of liquid. Furthermore, the composite material according to the invention is able, even under pressure, to hold the absorbed liquid so that it can not escape from the composite material again.
  • the carrier material present in the composite material according to the invention makes it possible for liquid, which impinges on the composite material in a small area, to be distributed through the carrier material over the entire composite material. This fact ensures that, even if the liquid to be absorbed impinges only on a small area of the composite material, the absorption force of the entire superabsorbent material present in the composite material can be utilized. Furthermore, the liquid quickly led away from the surface, resulting in a fast drainage. It is ensured according to the invention that liquid absorbed by the material according to the invention can not be removed from the foam even under pressure.
  • the present invention also relates to sanitary products, for example diapers, sanitary napkins, incontinence products, sealing materials, for example for pipes or tunnels, insulating materials, drying agents, water reservoirs, packaging and artificial plant substrates containing the composite material according to the invention.
  • the present invention also relates to the use of the composite material according to the invention in the field of hygiene, for example in baby diapers, incontinence products, sanitary napkins, in agriculture, for example as a water reservoir, for irrigation, for mixing with soil, in the automotive sector, for example in the seat backrests, in the steering wheel, in the furniture sector, for example in upholstered furniture, chairs, as a sealing material, for example in the construction industry, or in the cosmetics sector, for example in cosmetic sponges.
  • the Centrifuge Retention Capacity corresponds to the amount of fluid retained after centrifugation and the CRC value is determined as follows: A circular sample of the 5 cm diameter sheet is cut into two equal halves and one half into one Teabags (size 6 cm * 8.5 cm) are recorded, the weight of the sample before being placed in the tea bag, the tea bag is sealed and soaked in a 0.9% sodium chloride solution for 20 minutes Centrifuged at 1350 rpm for three minutes in a centrifuge, the weighed tea bag is weighed and the CRC value in g / m 2 is calculated according to the following formula:
  • Free Swell Capacity is the amount of fluid retained after dripping, which is equivalent to the CRC test, except that centrifugation is not required, and the FSC value is determined as follows: A circular sample of the sheet with a Diameter of 5 cm is cut into two equal halves and one of the halves is placed in a tea bag (6 cm * 8.5 cm), the weight of the sample is noted prior to insertion into the tea bag, the tea bag is sealed and left in for 20 minutes The teabag is then taken out of the sodium chloride solution and suspended in the air for 10 minutes, the tea bag is then weighed and the FSC value in g / m 2 is calculated according to the following formula:
  • FSC (Weighing Tea Bag - Sample Weight Dry - Blank) / A, where the blank value represents the average wet weight of an empty tea bag after hanging from two measurements and A equals the sample area in m 2 .
  • a modified melamine resin foam the procedure is analogous to that given in the example of WO 01/94436. Before the foaming of the propellant-containing melamine-formaldehyde precondensate, dry, superabsorbent polymer in amounts of 1 and 10%, based on the total solids content, are additionally added. The density of the obtained foam is about 9 g / l. The material is open-celled and elastic.
  • Luquasorb and SXL are acrylate-based crosslinked polymers, with fines being ⁇ 100 ⁇ m diameter particles. According to the method of WO 01/94436 is foamed for 6 min at 500 watts in the microwave. Then it is dewatered at 100 0 C in a circulating air dryer.

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Abstract

La présente invention concerne un matériau composite comprenant au moins un polymère superabsorbant et au moins une mousse aminoplaste élastique en tant que support, des produits d'hygiène, des matériaux d'étanchéité, des isolants, des déshydratants, des systèmes de réserve d'eau, des emballages et des substrats végétaux artificiels contenant un matériau composite, ainsi qu'un procédé de production d'un matériau composite contenant au moins une mousse aminoplaste élastique en tant que support et au moins un polymère superabsorbant, ce procédé comprenant les étapes suivantes : (A) préparation d'une solution ou d'une dispersion aqueuse contenant des composés précurseurs de la ou des mousses aminoplastes élastiques et éventuellement des additifs, (B) addition d'au moins un polymère superabsorbant à la solution ou à la dispersion aqueuse issue de l'étape (A), et (C) polymérisation des composés précurseurs de la ou des mousses aminoplastes élastiques dans la solution ou la dispersion aqueuse issue de l'étape (B) pour produire le matériau composite, par chauffage.
PCT/EP2008/063713 2007-10-30 2008-10-13 Matériau composite comprenant un polymère superabsorbant et un support et procédé de production de ce matériau par polymérisation du support en présence du polymère superabsorbant WO2009056436A2 (fr)

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DE112008002847T DE112008002847A5 (de) 2007-10-30 2008-10-13 Kompositmaterial aus einem Superabsorber und einem Trägermaterial und Verfahren zu dessen Herstellung durch Polymerisation des Trägermaterials in Gegenwart des Superabsorbers

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EP07119580 2007-10-30
EP07119580.4 2007-10-30

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5147345A (en) * 1991-08-12 1992-09-15 The Procter & Gamble Company High efficiency absorbent articles for incontinence management
WO2002006385A2 (fr) * 2000-07-15 2002-01-24 Basf Aktiengesellschaft Utilisation de mousses elastiques a alveoles ouvertes a base de produits de condensation melamine/formaldehyde, dans des articles hygieniques
US20040121905A1 (en) * 2002-12-23 2004-06-24 Kimberly - Clark Worldwide, Inc Method of making an absorbent composite
WO2006122934A2 (fr) * 2005-05-18 2006-11-23 Basf Aktiengesellschaft Procédé de fabrication de papier, de carton-pâte et de carton en présence de polymères pouvant gonfler en présence d'eau
WO2008019966A1 (fr) * 2006-08-17 2008-02-21 Basf Se DISPERSIONS AQUEUSES DE POLYMèreS en ÉMULSION CONTENANT DES GROUPES ESTER TERTIAIRES, réticulÉS, ET MATières ABSORBANT L'EAU FABRIQUÉS À PARTIR DE CELLES-CI SUR UN MATéRiau SUPPORT.

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5147345A (en) * 1991-08-12 1992-09-15 The Procter & Gamble Company High efficiency absorbent articles for incontinence management
WO2002006385A2 (fr) * 2000-07-15 2002-01-24 Basf Aktiengesellschaft Utilisation de mousses elastiques a alveoles ouvertes a base de produits de condensation melamine/formaldehyde, dans des articles hygieniques
US20040121905A1 (en) * 2002-12-23 2004-06-24 Kimberly - Clark Worldwide, Inc Method of making an absorbent composite
WO2006122934A2 (fr) * 2005-05-18 2006-11-23 Basf Aktiengesellschaft Procédé de fabrication de papier, de carton-pâte et de carton en présence de polymères pouvant gonfler en présence d'eau
WO2008019966A1 (fr) * 2006-08-17 2008-02-21 Basf Se DISPERSIONS AQUEUSES DE POLYMèreS en ÉMULSION CONTENANT DES GROUPES ESTER TERTIAIRES, réticulÉS, ET MATières ABSORBANT L'EAU FABRIQUÉS À PARTIR DE CELLES-CI SUR UN MATéRiau SUPPORT.

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WO2009056436A3 (fr) 2010-03-11

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