Patent GB-1356030-A (GB)
Title: Aqueous copolymer dispersions and coating compositions based thereon
IPC: C08F220/12
Filed: 1971-05-21
Abstract: 1356030 Aqueous polymer dispersions; coating compositions P U KUHLMANN 21 May 1971 [22 May 1970] 16479/71 Heading C3P Storage stable aqueous dispessions of a single copolymer, of which the K value (specific viscosity) is from 40 to 120, which dispersions thicken in the presence of an alkaline agent without forming a solution, contain as said copolymer the interpolymerization product of (a) 10-87% by weight of one or more esters of (meth)acrylic acid and a C 1  to C 18  alcohol, (b) 87-10% by weight of one or more monoethylenically unsaturated monomers (other than the above ester monomers) capable of forming water-insoluble homopolymers, (c) 3-12% by weight of one or more alkene-mono- or dicarboxylic acids or one or more monoalkyl esters of such dicarboxylic acids, and (d) 0-20% by weight of one or more monomers containing either an ethylenic linkage and a polar group (other than the above-mentioned acids) or a plurality of ethylenic linkages, the pH of the dispersion being from 2 to 5 and the solids content of the dispersion being from 30-60% by weight. The dispersions are obtained by copolymerizing the appropriate monomers in aqueous phase at a pH from 2 to 7 in the presence of from 0À01 to 3% (by weight of the monomers) of a free radical polymerization catalyst and of from 0À05 to 5% (by weight of the monomers) of a chain transfer agent. Polymerization is suitably effected in aqueous emulsion. Monomer (b) may be, for example, ethylene, propylene, isobutylene, diisobutylene, a vinyl or vinylidene halide, acrylonitrile, styrene, vinyl toluene, α-methyl styrene, vinyl acetate, vinyl propionate, a vinyl ester of Versatic acid ("Versatic" is a Registered Trade Mark), cetyl vinyl ether or dodecyl vinyl ether. Preferred as monomer (c) are acrylic, methacrylic, crotonic, maleic, fumaric, itaconic, citraconic or senecioic acid (#,#-dimethyl/acrylic acid) and anhydrides and monoalkyl esters of the stated dicarboxylic acids. Examples of the first type of monomer (d) are hydroxyalkyl (meth)acrylates, allyl alcohol, allyl glycolate, isobutene-diol, (meth)acrylamide and substituted derivatives, maleic amide or imide, sodium (meth)acrylate, vinyl- or styrene-sulphonic acid and alkali metal salts thereof, methacrylonitrile, 3-amino-crotonitrile, glycidyl- (meth)acrylate, alkyl cyanoacrylates or cyanoalkyl acrylates, methylene-glutaronitrile, amino- (meth)acrylates, acrolein, vinyl heterocyclic compounds, 2-chloro-acrylonitrile, acryloyl chloride, diacetone acrylamide, and fluoroalkylsulphonylaminoalkyl (meth)acrylates; examples of the second type of monomer (d) are allyl (meth)acrylate, tetra-allyl oxyethane, glycol di- (meth)acrylates, divinylbenzene, vinyl senecioate, divinyl carbinol, triacryloyl-hexahydro-striazine, butadiene, chlorobutadienes and isoprene. Useful chain transfer agents include alkyl mercaptans, carbon tetrachloride or tetrabromide, chloroform or triphenylmethane. Conventional peroxy, azo and redox catalysts may be used for the polymerization. The dispersions can be formulated into coating compositions by the addition of a pigment and, if desired, an alkaline agent, such as ammonia, caustic soda or sodium carbonate, to adjust the pH or thicken the composition. Other additives which may be incorporated include phosphates, polyphosphates, sodium sesquisilicates, calcium or ammonium stearate, sodium salt of EDTA, polyethoxylated compounds, natural or synthetic waxes, dicyanodiamide and derivatives, ethylene polyamines, polyols, urea and derivatives, sodium benzyl sulphanilate, alkyl formamides, alkylacetamides, alumina or zirconium salts, glyoxal, aminoplast or phenoplast resins, anti-cryptogamic agents, optical brighteners, and natural or synthetic colloids. Compositions containing kaolin as pigment are useful for coating paper or cardboard.