Process for the Preparation of Copolymer Latices

1,150,513. Emulsion copolymerization of vinyl esters. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 18 Sept., 1967 [19 Sept., 1966], No. 42334/67. Heading C3P. A process for the emulsion copolymerization of a vinyl ester of an a-alkyl and/or a,a-dialkylmonocarboxylic acid having at least 5 carbon atoms in the acid radical, with another monomer containing an olefinically unsaturated double bond comprises adding the comonomers to a reactor which already contains a 25-75% charge of copolymer latex formed from said comonomers and which is provided with a stirring and a cooling/heating device, the addition of comonomers taking place under copolymerization conditions and in the presence of a lyophilic protective colloid, the comonomers being added at such a rate and cooling being applied such that the reaction temperature remains at a substantially constant level until the reactor is filled, 25-75% of the latex contained in the reactor being used to start a second stage in a second reactor. In the example are used: water, solution of the sodium salt of a secondary C 14 alkyl sulphate, potassium persulphate, K 2 CO 3 , vinyl chloride, vinyl ester of a-branched monocarboxylic acids (prepared from C 8 -C 10 cracked olefins, CO and H 2 O), acrylic acid, nonylphenoxypolyethoxyethanol, ammonium carbonate, hydroxyethyl cellulose, vinyl pivalate and a vinyl ester of an acid prepared from C 14 -C 16 cracked olefines. Compositions containing dibutyl phthalate and TiO 2 are prepared.