GB641679A - Improvements in and relating to the copolymerisation of ethylene and vinyl chloride - Google Patents

Abstract

Copolymers of ethylene and vinyl chloride are produced by copolymerizing in the presence of an azo compound having both valencies of the azo group attached to different tertiary aliphatic carbon atoms each of which is attached to a neutral group hydrolysable to a carboxyl group. The azo compound is preferably wholly aliphatic and the neutral groups may be nitrile, carbalkoxy or carbonamide. Examples are a ,a 1 - azobis - (a ,g - dimethylvaleronitrile), dimethyl and diethyl a ,a 1-azodiisobutyrates, 1,11 - azodicyclohexane - carbonitrile, a ,a 1 - azobis - (a - methylbutyronitrile), a ,a 1 - azobis - (a - ethyl - butyronitrile), a ,a 1 - azodiisobutyrocarbonamide and a ,a 1-azobis-(a -cyclopropylpropionitrile). The amount of catalyst is preferably from 0.005-5 per cent by weight of polymerizable materials and the temperature of polymerization may be from 0-200 DEG C. The reaction may be effected in a pressure-resistant vessel employing pressures up to 3000 atmos. and in the presence or absence of water and/or other diluent or solvent, e.g. acetone, methanol, tert.-butyl alcohol, benzene, toluene, xylene, high-flash naphtha and cyclohexane. Emulsion or solution techniques can be used. When the proportion of ethylene in the copolymer is 5-20 per cent, the products are useful as films, finishes and fabric coatings. Oils of mol. weight 500-2500 are obtained when the ethylene content is 34-50 per cent and as non-volatile plasticizers are compatible with polymers of vinyl chloride, vinylidene chloride and methyl methacrylate, vinyl chloride-acetate copolymers and chlorinated rubber. With 50-80 per cent ethylene content, waxy products are obtained useful for coating paper, in candles and in polishes. A waxy product is described containing 72.9 per cent ethylene, which is soluble in aromatic hydrocarbons, mineral spirits and high-flash naphtha, and which also forms unsupported, flexible films. The copolymers are generally soluble in aromatic hydrocarbons. They may be modified by addition during polymerization of small amounts of such compounds as thiols, carbon tetrachloride, hexachlorethane, 1,3-dioxolane, maleic acid and anhydride, methacrylic and other mono-olefinic acids, vinylidene chloride and fluoride, vinyl fluoride and acetate, methyl and methoxyethyl methacrylates, tetra-fluoroethylene, isobutylene, carbon monoxide and sulphur dioxide; or by addition to the formed copolymers of such materials as pigments, dyestuffs, fillers, anti-oxidants, stabilizers, plasticizers, curing agents, resins and waxes. Specifications 622,374 and 631,225 are referred to.