GB838675A - Stable dispersions of high molecular weight elastomeric substances - Google Patents

Abstract

Aqueous dispersions of high molecular weight elastomers are made by mixing the elastomer with 3-3%, based on the weight of elastomer, of a copolymer formed from 1 mol. of a halfester of an alpha-beta ethylenically unsaturated dicarboxylic acid and a monohydric alcohol having at least 8 carbon atoms, e.g. a halfester of maleic or fumaric acid with decylol, dodecylol, octadecylol or a condensation product of dodecylphenol with at least 1 mol. of alkylene oxide, with 1-2 mols. of a monomeric monovinyl aromatic compound, e.g. styrene or styrene substituted in the aromatic nucleus by methyl, ethyl, isopropyl or butyl, an organic vinyl ester, e.g. vinyl acetate, vinyl propionate or vinyl benzoate, an ester of acrylic or methacrylic acid with an aliphatic monohydric alcohol having 4-20 carbon atoms or a conjugated diolefine having 4-6 carbon atoms, and then dispersing the mixture in water. The elastomers are exemplified by polymers of butadiene, isoprene, isobutylene and chlorobutadiene, copolymers of butadiene and styrene or acrylonitrile, chlorosulphonated polyethylene, polyethylenes of density 0.915-0.935, unvulcanized silicone rubber. In preparing the dispersions, protective colloids such as casein, polyvinyl alcohol or gelatine may be employed; the pH is preferably 5-10. The dispersions may contain 30-75% of dispersed substance. Examples are concerned with: (i) roller-mixing masticated natural rubber with a copolymer of maleic acid octadecyl semiester, styrene, butadiene or isoprene, and methacrylic acid dodecyl ester, and kneading into the mixture a 10% solution of casein to form a dispersion of use as an adhesive, e.g. in ondinbg paper to polyethylene, (ii) roller-mixing a butadiene 65 parts acrylonitrile 35 parts copolymer or a butadiene, 70 parts styrene 30 parts copolymer with a copolymer of maleic acid dodecyl semi-ester and styrene, incorporating oleic acid, kaolin, sulphur, a vulcanization accelerator, carbon black and a soft resin such as polyvinyl methyl ether, and kneading 10% casein solution or 2% soap solution into the mixture to form a dispersion useful for impregnating fabrics, (iii) kneading polydimethylsiloxane with a copolymer of maleic acid octadecyl semi-ester, styrene and methacrylic dodecyl ester, incorporating oleic acid, and stirring 15% ammoniacal casein solution into the mixture to form a dispersion useful as a mould release agent, (iv) roller-mixing chlorosulphonated polyethylene, paraffin oil, a copolymer of maleic acid dodecyl semi-ester and styrene, and oleic acid, and kneading the mixture with 10% ammoniacal casein solution to form a dispersion for impregnating fabrics, (v) preparing a mixture of masticated polyisobutylene, a copolymer of maleic acid octadecyl semi-ester, styrene, butadiene or isoprene, methacrylic acid dodecyl ester and oleic acid, and kneading the mixture with 10% casein solution to form a dispersion useful as an impregnating and coating agent. Specification 783,677 and U.S.A. Specification 2,448,756 are referred to.