GB594871A - Improvements relating to synthetic rubbers - Google Patents

Abstract

Copolymers of dienes and unsaturated nitriles having the formula CH2=C(R).CN where R is hydrogen or an alkyl group are deodorised by washing with a monohydric saturated alcohol containing not more than 4 C atoms. As dienes butadiene, isoprene, piperylene and 2 : 3-dimethyl butadiene, and as nitriles acryl-nitrile and methacrylonitrile are specified. The vulcanized or unvulcanized product may be treated with, e.g. methanol, ethanol or isopropanol. The copolymers may be prepared in aqueous emulsion in the presence of sodium sec-octadecyl sulphate, sodium linoleate or sodium oleate as emulsifier, carbon tetrachloride, bis-isopropyl xanthogen or dodecyl mercaptan as modifier, and benzoyl peroxide or potassium persulphate as catalyst. N,N1-di-beta - naphthyl - p - phenylene diamine may be added and the latex coagulated by adding brine and sulphuric acid. The copolymer may be vulcanized by heating with diphenyl guanidine or mercaptobenzothiazole, benzthiazyl-disulphide, zinc oxide, carbon black and sulphur and the vulcanized copolymer washed.ALSO:Synthetic rubbers of diene-unsaturated nitrile copolymers are washed with a saturated monohydric alcohol having not more than 4 C atoms to remove malodours. The copolymers may be vulcanized or unvulcanized. Dienes specified are butadiene, isoprene, piperylene and 2 : 3 dimethyl butadiene and as nitriles acrylonitrile and methacrylonitrile are specified.