GB636322A - Polymerization of alpha-substituted haloacrylic compounds - Google Patents

Abstract

Colourless transparent polymers are produced by polymerization of monomeric a -halogen acrylic acid compounds in the presence of an ester of an organic hydroxy acid, soluble in both the monomer and corresponding polymer, in amount from 0.1 per cent of the monomer to the limit of mixibility in the polymer and which reacts with any oxalyl halide compounds present or which may be formed during or after polymerization to yield colourless products. In general the ester does not exceed 4 per cent of the monomer. Specified hydroxy esters, which may be polymerizable, are methyl, ethyl, b -hydroxy ethyl, propyl, phenyl, cyclohexyl, vinyl, isopropenyl, allyl, methallyl, crotyl and cinnamyl glycollates and hydracrylates. Listed a -halogen acrylic acid compounds include methyl, ethyl, propyl, isopropyl, butyl, tert.-butyl, phenyl, benzyl, cyclohexyl, allyl and methallyl a -chlor- and a -brom-acrylates, a -chlor- and a -brom-acrylamides and the N-methyl derivatives thereof, and a -chlor-acrylonitrile. The process may be carried out by mass, solvent, granular or emulsion polymerization methods and may be promoted by use of light or other catalysts, e.g. benzoyl, succinyl peroxides, peracetic acid. Generally, polymerization is effected by heating, e.g. at 20-120 DEG C., preferably between 35 DEG and 65 DEG C., and the polymer subsequently hardened by heating between 100 DEG and 120 DEG C. for from 8-24 hours. The products may be moulded, e.g. to form optical media, which are scratch-resistant, transparent and non-brittle, which may be shaped by machining and polishing. Specifications 518,970, 527,494, 636,319, and U.S.A. Specification 2,247,790 are referred to.