GB621467A - Improvements in aqueous emulsion polymerization processes - Google Patents

Abstract

Conjugated open chain diolefins or styrene compounds or both are polymerized in aqueous emulsion in the presence of 10-50 per cent, based on the weight of water and solvent, of a water-soluble solvent which also dissolves the monomeric material, the said solvent being an alcohol containing not more than 6 carbon atoms, a ketone, aliphatic amine, alkanolamine, or amide, not being a polyvinyl alcohol derivative. The use of the emulsifying agents set out in Specification 469,319 as open to inspection under Sect. 91 is excluded. Solvents specified are ethanol, methanol, isopropanol, tert. butanol, acetone, methyl ethyl ketone, ethylamine, ethanolamine, triethanolamine, formamide and acetamide. Monomers specified are those disclosed in Specification 564,828, 570,596, 596,295 and 596,296; styrene; butadiene; 2-phenyl-, 2-methyl-, 2,3-dimethyl- and 2-chloro-butadienes-1,3; 2-methyl pentadiene-1,3; 2-methyl pentadiene-2,4; pentadiene-1,3; hexadiene-1,3; and hexadiene-2,4. Polymerization catalysts which may be used are hydrogen, urea and benzoyl peroxides, potassium persulphate and sodium perborate. Modifiers such as ethylene dichloride, chloroform, carbon tetrachloride, and surface tension regulators such as capryl or normal octyl alcohol may be added. As emulsifiers alkyl sulphates, alkyl naphthalene sulphonates, alkali metal sulpho-ethyl oleate, alkali metal alkyl benzene sulphonates, sodium or ammonium oleate or laurate, and glue, may be used. Some of the copolymers described in the examples are soluble in toluene and rubber-like products are vulcanized by heating with coal tar oil, zinc oxide, channel black, sulphur and mercaptobenzothiazole.