Improvements in or relating to plastic materials and to methods of production thereof

摘要

Vinyl esters or the lower alkyl esters of acrylic acid or its homologues, or mixtures of such esters are polymerized in admixture with an aqueous solution of 0,1 to 10 per cent of a polyvinyl alcohol, an amide or metallic salt of polyacrylic acid or its homologues, or mixtures of these, with continuous stirring during polymerization. The product consists of homogeneous solid granules which may be powder-like in bulk. The water-soluble polymer may be formed in situ. The pressure may be above or below atmospheric. Polymerization catalysts such as benzoyl peroxide, hydrogen peroxide, or benzaldehyde may be present. Plasticizers, dyes or fillers may be added before polymerization. In examples (1) and (2), methyl methacrylate which may contain benzoyl peroxide in solution is heated with an aqueous solution of polymeric sodium methacrylate; in examples (3) and (4) methyl methacrylate containing benzoyl peroxide in solution is heated with aqueous caustic soda or an aqueous solution of polymethacrylamide. Specification 427,494 is referred to.