GB642050A - Improvements in or relating to isobutylene copolymers - Google Patents

Abstract

Copolymers are made by copolymerizing a mixture of a major proportion of isobutylene, a minor proportion of a multi-olefin having from 4 to 14 carbon atoms per molecule and from 0.1 to 5 per cent by weight of the total mixture, of a divinyl aromatic compound at a temperature between - 40 DEG and - 160 DEG C. in the presence of a Friedel-Craft catalyst. Specified multi-olefins are butadiene, piperylene, dimethyl butadiene, myrcene, allo-ocymene, 2-methyl-3-butyl butadiene-1,3 and 2-methyl-4-nonyl butadiene-1,3. Specified divinyl aromatic compounds are ortho-, para- and metadivinyl benzene, divinyl-naphthyl compounds, divinyl-toluenes, divinyl-xylenes, and di-isopropenyl benzene. The Friedel-Crafts catalyst is employed as a solution in a low-freezing non-complex-forming solvent. The reduced temperature may be obtained by adding to the polymerization mixture liquid propane, ethane, ethylene, fluorochlor organic compounds or solid carbon dioxide. The polymerization may be effected in bulk or in the presence of a diluent, e.g. methyl or ethyl chloride, methylene or ethylene dichloride, chloroform, ethyl trichloride or carbon bisulphide. The diluents may be solvents for the catalyst; other specified solvents are sulphuryl chloride, heptane and hexanes. Specified catalysts are aluminium chloride or bromide, titanium tetrachloride and boron trifluoride. The copolymers may be compounded with plasticizers, e.g. hydrocarbons, dioctylphthalate; curing agents, e.g. sulphur, paraquinone dioxime, or dinitroso benzene; zinc oxide or stearic acid, carbon black, tetramethyl thiuram disulphide, 2-mercapto-benzothiazole, and copolymers of isobutylene and a multi-olefin. The copolymers may be extruded and made into inner tubes.