EP2385816A1 - Procédé de préparation de particules polymères hydrophiles inhibant les odeurs - Google Patents

Procédé de préparation de particules polymères hydrophiles inhibant les odeurs

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Publication number
EP2385816A1
EP2385816A1 EP09799618A EP09799618A EP2385816A1 EP 2385816 A1 EP2385816 A1 EP 2385816A1 EP 09799618 A EP09799618 A EP 09799618A EP 09799618 A EP09799618 A EP 09799618A EP 2385816 A1 EP2385816 A1 EP 2385816A1
Authority
EP
European Patent Office
Prior art keywords
polymer particles
water
coated
acid
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09799618A
Other languages
German (de)
English (en)
Inventor
Volker Braig
Thomas Daniel
Axel Jentzsch
Andreas Brockmeyer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
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Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP2385816A1 publication Critical patent/EP2385816A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F8/00—Chemical modification by after-treatment
    • C08F8/44—Preparation of metal salts or ammonium salts
    • 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
    • C08J3/12—Powdering or granulating
    • 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
    • C08J3/12—Powdering or granulating
    • C08J3/128—Polymer particles coated by inorganic and non-macromolecular organic compounds
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F13/00—Bandages or dressings; Absorbent pads
    • A61F13/15—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators
    • A61F13/53—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium
    • A61F2013/530481—Absorbent pads, e.g. sanitary towels, swabs or tampons for external or internal application to the body; Supporting or fastening means therefor; Tampon applicators characterised by the absorbing medium having superabsorbent materials, i.e. highly absorbent polymer gel materials
    • 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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T428/00—Stock material or miscellaneous articles
    • Y10T428/29—Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
    • Y10T428/2982—Particulate matter [e.g., sphere, flake, etc.]
    • Y10T428/2991—Coated
    • Y10T428/2998—Coated including synthetic resin or polymer

Definitions

  • the present invention relates to a process for the preparation of odor-inhibiting water-absorbing polymer particles based on ethylenically unsaturated, acid group-carrying monomers, wherein the acid groups are neutralized to 35 to 75 mol% and the polymer particles are coated with a chelating agent.
  • Water-absorbing polymers are used for the production of diapers, tampons, sanitary napkins and other hygiene articles, but also as water-retaining agents in agricultural horticulture.
  • WO 2006/109842 A1 describes a process for preparing water-absorbing polymer particles, wherein a monomer solution having a defined content of hydroquinone monomethyl ether and iron and little protoanemonin and furfural is polymerized.
  • the object of the present invention was to provide an improved process for producing odor-inhibiting water-absorbing polymer particles.
  • the object has been achieved by a process for producing water-absorbing polymer particles, comprising
  • the degree of neutralization is preferably from 40 to 70 mol%, preferably from 45 to 65 mol%, particularly preferably from 48 to 62 mol%, very particularly preferably from 50 to 60 mol%.
  • the base preferably contains less than 0.0001% by weight, more preferably less than 0.00002% by weight, most preferably less than 0.00001% by weight, of iron ions.
  • Suitable stainless steels are austenitic steels with, for example, at least 0.08 wt% carbon.
  • the austenitic steels advantageously contain further alloy constituents, preferably niobium or titanium.
  • the preferred stainless steels are stainless steels with the material number 1.45xx according to DIN EN 10020, where xx can be a natural number between 0 and 99.
  • Particularly preferred materials are the steels with the material numbers 1.4541 and 1.4571, in particular steel with the material number 1.4541.
  • Suitable polymeric materials are polyethylene, polypropylene, polyester, polyamide, polytetrafluoroethylene, polyvinyl chloride, epoxy resins and silicone resins. Most preferred is polypropylene.
  • the initiator systems used are essentially free of iron ions, with the initiator systems used preferably containing less than 0.1% by weight, more preferably less than 0.01% by weight, most preferably less than 0.001% by weight, iron ions , in each case based on the total amount of the initiator system.
  • Chelating agents are compounds having at least two functional groups capable of chelating with polyvalent metal ions.
  • Suitable chelating agents are, for example, ethylenediamine, diethylenetriamine, triethylenetetramine, iminodiacetic acid, 2,2 ', 2 "-triaminotriethylamine, nitrilotriacetic acid, ethylenediaminetetraacetic acid, oxalic acid, tartaric acid, citric acid, dimethylglyoxime, 8-hydroxyquinoline, 2,2'-bipyridine, 1 , 10-phenanthroline, dimercaptosuccinic acid.
  • acid groups in particular carboxylic acid groups, are preferred.
  • the at least one chelating agent preferably contains at least one, more preferably at least two, aminocarboxylic acid groups.
  • the aminocarboxylic acid group is preferably an aminodiacetic acid group.
  • the acid groups of the chelating agent are neutralized, i. the chelating agent is preferably used in neutralized form.
  • Suitable chelating agents having aminodiacetic acid groups are the tetrasodium salt of ethylenediaminetetraacetic acid, the trisodium salt of methylglycine diacetic acid, the trisodium salt of hydroxyethylethylenediaminetriacetic acid and the pentasodium salt of diethylenetriaminepentaacetic acid.
  • the polymer particles are preferably coated with 0.02 to 0.5 wt .-%, particularly preferably 0.05 to 0.3 wt .-%, most preferably 0.1 to 0.2 wt .-%, chelating agent.
  • the coating of the polymer particles is preferably carried out by means of mixers with moving mixing tools.
  • the mixers which can be used for surface postcrosslinking can also be used for the coating according to the invention.
  • the chelating agents are sprayed onto the polymer particles as a solution in a suitable solvent, preferably water, for coating.
  • the water-absorbing polymer particles are coated with a reducing agent and / or a zinc salt.
  • Suitable reducing agents are, for example, sodium sulfite, sodium hydrogen sulfite (sodium bisulfite), sodium dithionite, sulfinic acids and their salts, ascorbic acid, sodium hypophosphite, sodium phosphite, and also phosphinic acids and salts thereof.
  • salts of hypophosphorous acid for example sodium hypophosphite
  • salts of sulfinic acids are used, for example the disodium salt of 2-hydroxy-2-sulfinatoacetic acid.
  • the reducing agent but preferably a mixture of the sodium salt of 2-hydroxy-2-sulfinatoacetic acid, the disodium salt of 2-hydroxy-2-sulfonatoacetic acid and sodium bisulfite is used.
  • Such mixtures are available as Brüggolite® FF6 and Brüggolite® FF7 (Brüggemann Chemicals; Heilbronn; DE).
  • the amount of reducing agent used is preferably 0.01 to 5 wt .-%, particularly preferably 0.05 to 2 wt .-%, most preferably 0.1 to 1 wt .-%, each based on the water-absorbing polymer.
  • Suitable zinc salts are, for example, zinc hydroxide, zinc sulfate, zinc chloride, zinc acetate and zinc lactate.
  • Zinc salts of fatty acids for example, ricinoleic acid are preferably used.
  • the amount of zinc salt used is preferably 0.01 to 5 wt .-%, more preferably 0.05 to 2 wt .-%, most preferably 0.1 to 1 wt .-%, each based on the water-absorbing polymer ,
  • the reducing agents or zinc salts are usually used as a solution in a suitable solvent, preferably water.
  • the present invention is based on the finding that the combination of slightly acidic water-absorbing polymer particles with chelating agents leads to a significantly improved odor inhibition.
  • the chelating agents probably deactivate urease by complexing the essential nickel ions.
  • iron ions present in the water-absorbing polymer particles compete for the chelating agents.
  • present iron ions in conjunction with chelating agents may also be the cause of undesired discoloration.
  • iron ions for example, the frequently used as a base sodium hydroxide is considered. To carry out the process according to the invention, care must be taken that the caustic soda solution used has a very low proportion of iron ions.
  • the pipelines in which the base is supplied for neutralization critical.
  • caustic soda is not considered corrosive to unalloyed steels and is even used for passivation.
  • caustic soda from unalloyed steels dissolves small traces of iron ions. Therefore, the base must be made by means of a pipeline
  • Stainless steel can be pumped into the neutralization. Due to the associated lower input of iron ions, it is also advantageous to use stainless steel or a polymeric material as material for the other product-contacting parts of the production process.
  • an initiator system is used in which as possible no iron ions are used as a catalyst.
  • the tendency to discoloration can be favorably influenced.
  • the water-absorbing polymer particles are obtained, for example, by polymerization of a monomer solution or suspension containing
  • the monomers a) are preferably water-soluble, i. the solubility in water at 23 ° C. is typically at least 1 g / 100 g of water, preferably at least 5 g / 100 g of water, more preferably at least 25 g / 100 g of water, most preferably at least 35 g / 100 g of water.
  • Suitable monomers a) are, for example, ethylenically unsaturated carboxylic acids, such as acrylic acid, methacrylic acid, and itaconic acid. Particularly preferred monomers are acrylic acid and methacrylic acid. Very particular preference is given to acrylic acid.
  • Suitable monomers a) are, for example, ethylenically unsaturated sulfonic acids, such as styrenesulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid (AMPS).
  • sulfonic acids such as styrenesulfonic acid and 2-acrylamido-2-methylpropanesulfonic acid (AMPS).
  • AMPS 2-acrylamido-2-methylpropanesulfonic acid
  • a suitable monomer a) is, for example, an acrylic acid purified according to WO 2004/035514 A1 with 99.8460% by weight of acrylic acid, 0.0950% by weight of acetic acid, 0.0332% by weight of water, 0.0203% by weight.
  • Propionic acid 0.0001% by weight of furfurals, 0.0001% by weight of maleic anhydride, 0.0003% by weight of diacrylic acid and 0.0050% by weight of hydroquinone monomethyl ether.
  • the proportion of acrylic acid and / or salts thereof in the total amount of monomers a) is preferably at least 50 mol%, particularly preferably at least 90 mol%, very particularly preferably at least 95 mol%.
  • the monomers a) usually contain polymerization inhibitors, preferably hydroquinone half ethers, as a storage stabilizer.
  • the monomer solution preferably contains up to 250 ppm by weight, preferably at most 130 ppm by weight, more preferably at most 70 ppm by weight, preferably at least 10 ppm by weight, more preferably at least 30 ppm by weight, in particular by 50% by weight .-ppm, hydroquinone, in each case based on the unneutralized monomer a).
  • an ethylenically unsaturated, acid group-carrying monomer having a corresponding content of hydroquinone half-ether can be used to prepare the monomer solution.
  • hydroquinone half ethers are hydroquinone monomethyl ether (MEHQ) and / or alpha-tocopherol (vitamin E).
  • Suitable crosslinkers b) are compounds having at least two groups suitable for crosslinking. Such groups are, for example, ethylenically unsaturated groups which can be radically copolymerized into the polymer chain, and functional groups which can form covalent bonds with the acid groups of the monomer a). Furthermore, polyvalent metal salts which can form coordinative bonds with at least two acid groups of the monomer a) are also suitable as crosslinking agents b).
  • Crosslinkers b) are preferably compounds having at least two polymerizable groups which can be incorporated in the polymer network in free-radically polymerized form.
  • Suitable crosslinkers b) are, for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, allyl methacrylate, trimethylolpropane triacrylate, triallylamine, tetraallylammonium chloride, tetraallyloxyethane, as described in EP 0 530 438 A1, di- and triacrylates, as in EP 0 547 847 A1, EP 0 559 476 A1, EP 0 632 068 A1, WO 93/21237 A1, WO 2003/104299 A1, WO 2003/104300 A1, WO 2003/104301 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
  • Preferred crosslinkers b) are pentaerythritol triallyl ether, tetraalloxyethane, methylenebis methacrylamide, 15-times ethoxylated trimethylolpropane triacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate and triallylamine.
  • 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 2003/104301 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 are particularly preferred.
  • triacrylates of 3 to 5 times ethoxylated and / or propoxylated glycerol are particularly preferred.
  • the amount of crosslinker b) is preferably from 0.05 to 1, 5 wt .-%, particularly preferably 0.1 to 1 wt .-%, most preferably 0.3 to 0.6 wt .-%, each based on Monomer a).
  • the centrifuge retention capacity decreases and the absorption under a pressure of 21.0 g / cm 2 passes through a maximum.
  • initiators c) it is possible to use all compounds which generate free radicals under the polymerization conditions, for example thermal initiators, redox initiators, photoinitiators.
  • Suitable redox initiators are sodium peroxodisulfate / ascorbic acid, hydrogen peroxide / ascorbic acid, sodium peroxodisulfate / sodium bisulfite and hydrogen peroxide / sodium bisulfite.
  • Preference is given to using mixtures of thermal initiators and redox initiators, such as sodium peroxodisulfate / hydrogen peroxide / ascorbic acid.
  • a reducing component but is preferably a mixture of the sodium salt of 2-hydroxy-2-sulfinatoacetic acid, the disodium salt of 2-hydroxy-2-sulfonatoacetic acid and
  • Examples of ethylenically unsaturated monomers d) which can be copolymerized with the ethylenically unsaturated monomers having acid groups are acrylamide, methacrylamide, hydroxyethyl acrylate, hydroxyethyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, diethylaminopropyl acrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate.
  • water-soluble polymers e it is possible to use polyvinyl alcohol, polyvinylpyrrolidone, starch, starch derivatives, modified cellulose, such as methylcellulose or hydroxyethylcellulose, gelatin, polyglycols or polyacrylic acids, preferably starch, starch derivatives and modified cellulose.
  • an aqueous monomer solution is used.
  • the water content of the monomer solution is preferably from 40 to 75 wt .-%, particularly preferably from 45 to 70 wt .-%, most preferably from 50 to 65 wt .-%.
  • monomer suspensions ie monomer solutions with excess monomer a), for example, sodium acrylate, use.
  • monomer suspensions ie monomer solutions with excess monomer a), for example, sodium acrylate
  • the monomer solution may be polymerized prior to polymerization by inerting, i. Flow through with an inert gas, preferably nitrogen or carbon dioxide, are freed of dissolved oxygen.
  • the oxygen content of the monomer solution before the polymerization is preferably reduced to less than 1 ppm by weight, more preferably to less than 0.5 ppm by weight, most preferably to less than 0.1 ppm by weight.
  • Suitable reactors are, for example, kneading reactors or belt reactors.
  • the polymer gel resulting from the polymerization of an aqueous monomer solution or suspension is continuously comminuted by, for example, counter-rotating stirring shafts, as described in WO 2001/038402 A1.
  • the polymerization on the belt is described, for example, in DE 38 25 366 A1 and US Pat. No. 6,241,928.
  • Polymerization in a belt reactor produces a polymer gel which must be comminuted in a further process step, for example in an extruder or kneader.
  • the acid groups of the polymer gels obtained are usually partially neutralized.
  • the neutralization is preferably carried out at the stage of the monomers. This is usually done by mixing the neutralizing agent as an aqueous solution or preferably as a solid.
  • the degree of neutralization is preferably from 40 to 70 mol%, preferably from 45 to 65 mol%, particularly preferably from 48 to 62 mol%, very particularly preferably from 50 to 60 mol%, it being possible to use the customary neutralizing agents, preferably alkali metal hydroxides, alkali metal oxides, alkali metal carbonates or alkali metal bicarbonates and mixtures thereof. Instead of alkali metal salts and ammonium salts can be used.
  • Sodium and potassium are particularly preferred as alkali metals, but most preferred are potassium hydroxide, sodium hydroxide, sodium carbonate or sodium bicarbonate and mixtures thereof.
  • the polymer gel is also possible to carry out the neutralization after the polymerization at the stage of the polymer gel formed during the polymerization. Furthermore, it is possible up to 40 mol%, preferably 10 to 30 mol%, particularly preferably 15 to 25 mol% of the acid groups to neutralize prior to the polymerization by a part of the neutralizing agent already added to the monomer solution and the desired final degree of neutralization is set only after the polymerization at the level of the polymer gel. If the polymer gel is at least partially neutralized after the polymerization, the polymer gel is preferably comminuted mechanically, for example by means of an extruder, wherein the neutralizing agent can be sprayed, sprinkled or poured on and then thoroughly mixed in. For this purpose, the gel mass obtained can be extruded several times for homogenization.
  • the polymer gel is then preferably dried with a belt dryer until the residual moisture content is preferably 0.5 to 15 wt .-%, particularly preferably 1 to 10 wt .-%, most preferably 2 to 8 wt .-%, wherein the residual moisture content according to determined by EDANA (European Disposables and Nonwovens Association) Test Method No. WSP 230.2-05 "Moisture Content". If the residual moisture content is too high, the dried polymer gel has too low a glass transition temperature T 9 and is difficult to process further. If the residual moisture content is too low, the dried polymer gel is too brittle and in the subsequent comminution steps undesirably large amounts of polymer particles with too small particle size (“fines") are produced. %, particularly preferably from 35 to 70% by weight, very particularly preferably from 40 to 60% by weight. Optionally, however, a fluidized bed dryer or a paddle dryer can also be used for the drying.
  • the dried polymer gel is then ground and classified, wherein for grinding usually one- or multi-stage roller mills, preferably two- or three-stage roller mills, pin mills, hammer mills or vibratory mills, can be used.
  • the mean particle size of the polymer fraction separated as a product fraction is preferably at least 200 ⁇ m, more preferably from 250 to 600 ⁇ m, very particularly from 300 to 500 ⁇ m.
  • the mean particle size of the product fraction can be determined by means of the test method No. WSP 220.2-05 "Particle Size Distribution" recommended by the EDANA (European Disposables and Nonwovens Association), in which the mass fractions of the sieve fractions are cumulatively applied and the average particle size is determined graphically.
  • the mean particle size here is the value of the mesh size, which results for accumulated 50 wt .-%.
  • the proportion of particles having a particle size of at least 150 .mu.m is preferably at least 90 wt .-%, more preferably at least 95 wt .-%, most preferably at least 98 wt .-%.
  • Polymer particles with too small particle size lower the permeability (SFC). Therefore, the proportion of too small polymer particles ("fines") should be low.
  • Too small polymer particles are therefore usually separated and recycled to the process. This is preferably done before, during or immediately after the polymerization, i. before drying the polymer gel.
  • the too small polymer particles can be moistened with water and / or aqueous surfactant before or during the recycling.
  • the too small polymer particles are preferably added during the last third of the polymerization.
  • the too small polymer particles can be difficult to incorporate into the resulting polymer gel. Insufficiently incorporated too small polymer particles, however, dissolve again during the grinding of the dried polymer gel, are therefore separated again during classification and increase the amount of recycled too small polymer particles.
  • the proportion of particles having a particle size of at most 850 microns is preferably at least 90 wt .-%, more preferably at least 95 wt .-%, most preferably at least 98 wt .-%.
  • the proportion of particles having a particle size of at most 600 ⁇ m is preferably at least 90% by weight, particularly preferably at least 95% by weight, very particularly preferably at least 98% by weight.
  • Polymer particles with too large particle size reduce the swelling rate. Therefore, the proportion of polymer particles too large should also be low. Too large polymer particles are therefore usually separated and recycled to the grinding of the dried polymer gel.
  • the polymer particles can be surface postcrosslinked to further improve the properties.
  • Suitable surface postcrosslinkers are compounds containing groups that can form covalent bonds with at least two carboxylate groups of the polymer particles.
  • Suitable compounds are, for example, polyfunctional amines, polyfunctional amidoamines, polyfunctional epoxides, as described in EP 0 083 022 A2, EP 0 543 303 A1 and EP 0 937 736 A2, di- or polyfunctional alcohols, as described in DE 33 14 019 A1, DE 35 23 617 A1 and EP 0 450 922 A2, or ⁇ -hydroxyalkylamides, as described in DE 102 04 938 A1 and US Pat. No. 6,239,230.
  • Preferred surface postcrosslinkers are ethylene carbonate, ethylene glycol diglycidyl ether, reaction products of polyamides with epichlorohydrin and mixtures of propylene glycol and 1,4-butanediol.
  • Very particularly preferred surface postcrosslinkers are 2-hydroxyethyloxazolidin-2-one, oxazolidin-2-one and 1,3-propanediol.
  • the amount of surface postcrosslinker is preferably 0.001 to 2 wt .-%, more preferably 0.02 to 1 wt .-%, most preferably 0.05 to 0.2 wt .-%, each based on the polymer particles.
  • polyvalent cations are applied to the particle surface before, during or after the surface postcrosslinking in addition to the surface postcrosslinkers.
  • the polyvalent cations which can be used in the process according to the invention are, for example, divalent cations, such as the cations of zinc, magnesium, calcium, Iron and strontium, trivalent cations, such as the cations of aluminum, iron, chromium, rare earths and manganese, tetravalent cations, such as the cations of titanium and zirconium.
  • divalent cations such as the cations of zinc, magnesium, calcium, Iron and strontium
  • trivalent cations such as the cations of aluminum, iron, chromium, rare earths and manganese
  • tetravalent cations such as the cations of titanium and zirconium.
  • chloride, bromide, sulfate, hydrogensulfate, carbonate, hydrogencarbonate, nitrate, phosphate, hydrogenphosphate, dihydrogenphosphate and carboxylate, such as acetate and lactate are possible.
  • Aluminum sulfate and aluminum lactate are
  • the amount of polyvalent cation used is, for example, 0.001 to 1.5% by weight, preferably 0.005 to 1% by weight, particularly preferably 0.02 to 0.8% by weight. in each case based on the polymer particles.
  • the surface postcrosslinking is usually carried out so that a solution of the surface postcrosslinker is sprayed onto the dried polymer particles. Subsequent to the spraying, the surface postcrosslinker coated polymer particles are thermally dried, whereby the surface postcrosslinking reaction can take place both before and during drying.
  • the spraying of a solution of the surface postcrosslinker is preferably carried out in mixers with agitated mixing tools, such as screw mixers, disc mixers and paddle mixers.
  • agitated mixing tools such as screw mixers, disc mixers and paddle mixers.
  • horizontal mixers such as paddle mixers
  • vertical mixers very particularly preferred are vertical mixers.
  • the distinction between horizontal mixer and vertical mixer is made by the storage of the mixing shaft, i.
  • Horizontal mixers have a horizontally mounted mixing shaft and vertical mixers have a vertically mounted mixing shaft.
  • Suitable mixers are, for example, Horizontal Pflugschar® mixers (Gebr.
  • the surface postcrosslinkers are typically used as an aqueous solution.
  • the penetration depth of the surface postcrosslinker into the polymer particles can be adjusted by the content of nonaqueous solvent or total solvent amount.
  • solvent for example isopropanol / water, 1,3-propanediol / water and propylene glycol. col / water, wherein the mixture mass ratio is preferably from 20:80 to 40:60.
  • the thermal drying is preferably carried out in contact dryers, particularly preferably paddle dryers, very particularly preferably disc dryers.
  • Suitable dryers include Hosokawa Bepex® Horizontal Paddle Dryer (Hosokawa Micron GmbH, Leingart, DE), Hosokawa Bepex® Disc Dryer (Hosokawa Micron GmbH, Leingart, DE), and Nara Paddle Dryer (NARA Machinery Europe, Frechen, DE).
  • fluidized bed dryers can also be used.
  • the drying can take place in the mixer itself, by heating the jacket or blowing hot air.
  • a downstream dryer such as a hopper dryer, a rotary kiln or a heatable screw. Particularly advantageous is mixed and dried in a fluidized bed dryer.
  • Preferred drying temperatures are in the range 100 to 250 0 C, preferably 120 to 220 0 C, particularly preferably 130 to 210 ° C most preferably 150 to 200 0 C. by weight, the preferred residence time at this temperature in the reaction mixer or dryer is preferably at least 10 minutes , more preferably at least 20 minutes, most preferably at least 30 minutes, and usually at most 60 minutes.
  • the surface-postcrosslinked polymer particles can be classified again, wherein too small and / or too large polymer particles are separated and recycled into the process.
  • the surface-postcrosslinked polymer particles can be coated or post-moistened for further improvement of the properties.
  • the post-wetting is preferably carried out at 30 to 80 ° C, more preferably at 35 to 70 ° C, most preferably at 40 to 60 0 C performed. If the temperatures are too low, the water-absorbing polymer particles tend to clump together and at higher temperatures water is already noticeably evaporating.
  • the amount of water used for the rewetting is preferably from 1 to 10 wt .-%, particularly preferably from 2 to 8 wt .-%, most preferably from 3 to 5 wt .-%.
  • Suitable coatings for improving the swelling rate and the permeability are, for example, inorganic inert substances, such as water-insoluble metal salts, organic polymers, cationic polymers and di- or polyvalent metal cations.
  • Suitable coatings for dust binding are For example, polyols.
  • Suitable coatings against the undesirable tendency for the polymer particles to cake are, for example, fumed silica, such as Aerosil® 200, and surfactants, such as Span® 20.
  • Another object of the present invention are the water-absorbing polymer particles prepared according to the inventive method.
  • the water-absorbing polymer particles produced according to the method of the invention have a low content of iron ions.
  • the content of iron ions is less than 0.001% by weight, preferably less than 0.0005% by weight, more preferably less than 0.0001% by weight, very particularly preferably less than 0.00002% by weight.
  • the weight ratio of iron ions to the chelating agent is less than 0.02, preferably less than 0.01, more preferably less than 0.005, most preferably less than 0.001.
  • the water-absorbing polymer particles produced by the process according to the invention have a moisture content of preferably 1 to 10 wt .-%, particularly preferably 2 to 8 wt .-%, most preferably 3 to 5 wt .-%, wherein the water content according to the EDANA (European Disposables and Nonwovens Association) recommended test method no. WSP 230.2-05 "Moisture Content”.
  • EDANA European Disposables and Nonwovens Association
  • the water-absorbing polymer particles prepared according to the method of the invention have a centrifuge retention capacity (CRC) of typically at least 15 g / g, preferably at least 20 g / g, preferably at least 22 g / g, more preferably at least 24 g / g, most preferably at least 26 g / g, up.
  • the centrifuge retention capacity (CRC) of the water-absorbing polymer particles is usually less than 60 g / g.
  • the centrifuge retention capacity (CRC) is determined according to the test method No. WSP 241.2-05 "Centrifuge Retention Capacity" recommended by the EDANA (European Disposables and Nonwovens Association).
  • the water-absorbing polymer particles produced by the process according to the invention have an absorption under a pressure of 49.2 g / cm 2 of typically at least 15 g / g, preferably at least 20 g / g, preferably at least 22 g / g, particularly preferably at least 24 g / g, most preferably at least 26 g / g, on.
  • the absorption under a pressure of 49.2 g / cm 2 of the water-absorbent polymer particles is usually less than 35 g / g.
  • the absorption under a pressure of 49.2 g / cm 2 is analogous to that of the EDANA (European Dispo- sables and Nonwovens Association) recommended test method no. WSP 242.2-05 "absorption under pressure", wherein instead of a pressure of 21, 0 g / cm 2, a pressure of 49.2 g / cm 2 is set.
  • the color of the samples was measured with a spectrophotometer (LabScan XE, Hunter Associates Laboratory, Inc., US).
  • the water-absorbing polymer particles (SAP) were filled in the lid of a polystyrene Petri dish (inner diameter 3.9 cm) and measured with the following settings:
  • UV filter Nominal Stdz Mode 0/45

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Medicinal Chemistry (AREA)
  • Materials Engineering (AREA)
  • Epidemiology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Hematology (AREA)
  • Dispersion Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Processes Of Treating Macromolecular Substances (AREA)
  • Absorbent Articles And Supports Therefor (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

L'invention se rapporte à un procédé de préparation de particules polymères hydrophiles inhibant les odeurs à base de monomères porteurs de groupes acides à insaturation éthylénique, lesdits groupes acides étant neutralisés jusqu'à 35 à 70 % en moles et les particules polymères étant recouvertes d'un chélateur.
EP09799618A 2009-01-09 2009-12-17 Procédé de préparation de particules polymères hydrophiles inhibant les odeurs Withdrawn EP2385816A1 (fr)

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US14343609P 2009-01-09 2009-01-09
PCT/EP2009/067421 WO2010079075A1 (fr) 2009-01-09 2009-12-17 Procédé de préparation de particules polymères hydrophiles inhibant les odeurs

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EP2673011B2 (fr) * 2011-02-07 2019-01-16 Basf Se Procede pour la préparation des particules polymères absorbant de l'eau ayant une haute vitesse de gonflement
CN103930201B (zh) 2011-11-15 2016-04-27 株式会社日本触媒 吸水剂组合物及其制造方法、以及其保管及库存方法
US9126186B2 (en) * 2011-11-18 2015-09-08 Basf Se Process for producing thermally surface postcrosslinked water-absorbing polymer particles
US20150306272A1 (en) * 2012-12-20 2015-10-29 Basf Se Odour-inhibiting superabsorber
WO2015053372A1 (fr) * 2013-10-09 2015-04-16 株式会社日本触媒 Absorbeur d'eau particulaire comprenant une résine d'absorption d'eau en tant que constituant principal et son processus de fabrication

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SG86324A1 (en) * 1997-07-03 2002-02-19 Kao Corp Superabsorbent resin composition
EP2112172B2 (fr) * 2007-01-24 2018-10-17 Nippon Shokubai Co., Ltd. Polymère particulaire absorbant l'eau et son procédé de fabrication
WO2008096713A1 (fr) * 2007-02-05 2008-08-14 Nippon Shokubai Co., Ltd. Absorbant d'eau granulaire et son procédé de fabrication
SA08290402B1 (ar) * 2007-07-04 2014-05-22 نيبون شوكوباي كو. ، ليمتد عامل دقائقي ماص للماء وطريقة لتصنيعه

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JP2012514670A (ja) 2012-06-28
US20100178513A1 (en) 2010-07-15
CN102348435A (zh) 2012-02-08

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