GB582305A - Improvements in the vulcanizing of synthetic rubber - Google Patents

Abstract

Sulphur-vulcanizable synthetic rubbers are vulcanized by treatment with xanthic polysulphides having the structural formula <FORM:0582305/V/1> where R is an organic radical having an alkyl carbon atom linked to the oxygen and n is an integer greater than 1. R is preferably alkyl, methyl, ethyl, propyl, butyl, amyl, hexyl, octyl, decyl, lauryl cyclohexyl, benzyl, methoxy ethyl or ethoxy ethyl. Optimum results are obtained with an amount of the xanthic polysulphide which contains 2 per cent. of sulphur based on the synthetic rubber. The preferred synthetic rubbers are the emulsion copolymers of butadiene 1:3 with monovinyl compounds. Fillers and pigments such as stearic acid, carbon black and zinc oxide may also be added and in addition accelerators such as N cyclohexyl 2 benzothiazole sulphenamide, mercaptobenzothiazole, benzothiazyl disulphide, di-(benzothiazyl thiol) dimethyl urea, benzoyl 2-benzothiazyl sulphide, bis(6-phenyl benzothiazyl) disulphide, bis (6-nitro benzothiazyl) disulphide, the cyclohexamine salt of 2 mercaptobenzo-thiazole, bis(4-phenyl benzothiazyl) disulphide, a mixture of bis 4, 5-dimethyl thiazyl disulphide and bis-4-ethyl thiazyl disulphide, piperidine cyclopentamethylene dithiocarbamate, tetramethyl thiuram disulphide and monosulphide, and the carbon disulphide reaction product of methylene dipiperidine. Examples are given of several mixes containing copolymers of butadiene with styrene or acrylonitrile and xanthic polysulphides vulcanized at 40 lbs. per square inch steam pressure for periods of 60-180 minutes.