GB568964A - Improvements in or relating to the manufacture of synthetic rubber-like materials - Google Patents

Abstract

Synthetic rubber-like materials are made by polymerizing a mixture of a 1,3-diene (at least 50 per cent of total), styrene (at least 50 per cent of the remainder) and a vinylethinyl carbinol (at least 1 per cent of total). Dienes specified are 1,3-butadiene, isoprene and 2,3-dimethyl - 1,3 - butadiene. Carbinols specified are vinylethinyl carbinol, monomethyl, mono-n-propyl, diethyl, methyl, octyl, tetramethylene, methyl phenyl and furyl vinylethinyl carbinols, whose preparation is described in U.S.A. Specifications 1,963,934 and 1,963,935. The polymerization may be carried out in emulsion, preferably in the presence of lauryl mercaptan, a catalyst, e.g. potassium persulphate and a complex cyanide, e.g. potassium ferricyanide. Preferred emulsifying agents are those formed by neutralizing oleic acid or a mixture of oleic acid and rosin with sodium hydroxide. Stabilizers, e.g. sodium naphthalene sulphonates or sodium dinaphthyl methane sulphonates may be present. Coagulation may be effected by sodium chloride and acetic acid, magnesium sulphate or aluminium sulphate or by adding alcohol or freezing in thin layers as described in Specification 504,466. A mixture of diphenylamine and phenyl-a -naphthylamine may be added before coagulation. The product may be compounded with carbon black, stearic acid, sulphur zinc oxide and 2-mercaptothiazoline or mercapto benzothiazole and vulcanized. Specifications 512,479, 513,116, 519,730 and 529,838 also are referred to.