GB589248A - Improvements in or relating to the preparation of synthetic rubber-like materials - Google Patents

Abstract

Conjugated diolefines are polymerized in soap emulsion with an oxygen-liberating catalyst with or without a copolymerizable hydrocarbon or substituted hydrocarbon containing a single CH2 = C< group, coagulated with brine, an alkali metal or ammonium hydroxide added to the slurry and the polymer particles separated, washed and dried. As soaps, mixtures of oleic acid and alkali hydroxides are used, anti-oxidants, e.g. hydroquinone and phenyl - b - naphthylamine, may be added at the completion of polymerization. If desired after washing, the polymer particles may be reslurried in water containing sufficient alkali to adjust the pH to 10-11, and then filtered, washed and dried. Preferably, 0.25-1.0 per cent of hydroxide is added to the slurry. In addition, 0.1-0.5 per cent of an aliphatic mercaptan having 7 or more carbon atoms, e.g. the mercaptan of sulphonated lauryl alcohol, may be added to the polymerization mixture. Carbon dioxide may be added after coagulation to increase the particle size of the polymer. Specified diolefines are butadiene, isoprene and piperylene and mixtures thereof, and copolymerizable materials include acrylonitrile, methacrylonitrile, acrylic acid esters, methyl vinyl ketone, styrene and substituted styrenes. The copolymer may be compounded with zinc benzothiazyl sulphide and sulphur and vulcanized.