GB991134A - Process for the manufacture of vinyl chloride polymers - Google Patents

Abstract

Vinyl chloride or a mixture thereof with not more than 10 weight per cent of a copolymerizable monomer is polymerized in aqueous dispersion in the presence of a monomer-soluble polymerization catalyst and as protective colloids poly-N-vinyl pyrrolidone or a water-soluble copolymer thereof and a water-soluble cellulose ether, polyvinyl alcohol or polyvinyl phosphate, the proportions of N-vinyl pyrrolidone polymer and of the cellulose ether, polyvinyl alcohol or polyvinyl phosphate each being 0.001 to 0.5 weight per cent based on the monomer. The preferred comonomer is vinyl acetate. Copolymers of N-vinyl pyrrolidone with vinyl, acrylic, methacrylic and maleic esters and particularly unsaturated acid amides may be used. The cellulose ether may be methyl cellulose, ethyl cellulose, methyl hydroxyethyl cellulose or methyl hydroxypropyl cellulose. Conventional anionic, cationic and non-ionic emulsifiers, e.g. soaps, salts of phosphoric acid partial esters, alkyl sulphates and aralkyl sulphonates, quaternary ammonium compounds, dodecyl betaine, and condensates of ethylene oxide with alcohols, acids and polypropylene oxide; and salts, e.g. alkali and alkaline earth metal chlorides, carbonates, sulphates and phosphates, may also be present. Specified catalysts are diacyl peroxides, cumene hydroperoxide, acetyl cyclohexane sulphonyl peroxide. In examples, vinyl chloride is polymerized in the presence of polyvinyl pyrrolidone, sodium bicarbonate and (1) methyl, hydroxyethyl or methyl hydroxypropyl cellulose and dilauroyl peroxide, (2) methyl cellulose and dilauroyl peroxide, (3) methyl cellulose, dilauroyl peroxide and acetyl cyclohexane sulphonyl peroxide, (4) polyvinyl alcohol and dilauroyl peroxide and (5) polyvinyl ammonium phosphate. The polymers may be compounded with dioctyl phthalate and dibasic lead stearate and used for insulating electrical conductors. Specifications 737,127, 754,876 and 775,409 are referred to.