GB654026A - Polymeric compositions intended for moulding or extrusion - Google Patents

Abstract

A layer of liquid containing one or more compounds having a single CH2=C< group per molecule and a dissolved depolymerization inhibitor supported on a moving surface is polymerized to the solid state by light rays from above the layer in the absence of oxygen in the space above the layer, e.g. by passing a current of inert gas over the layer. The liquid may contain a small amount of dissolved polymer, a chain transfer reagent, plasticizers, dyes or pigments. The moving surface may be an endless flexible band with synthetic rubber side walls floating on a liquid medium, e.g. water. The compounds may be vinyl acetate, styrene, or an ester of acrylic, alpha chloracrylic or methacrylic acid, e.g. isopropyl or methyl methacrylate. Specified depolymerization inhibitors are ethyl, amyl, octyl, dodecyl, hexadecyl, and octadecyl mercaptan, pentadecane thiol-8, ethane dithiol, dimethylene dithiol, decanedithiol-1,10, didodecyl disulphide, thioglycollic acid, thioacetic acid, mercaptoethanol, diisopropyl xanthogen disulphide, penta-acetyl 1 - thiosorbitol, methyl - 2 - methyl - 3 - mercaptopropionate, monothioglycol, tetraethyl thiuram disulphide, dibutyl thioether, didodecyl thioether, benzyl or p-tolyl mercaptan and the aliphatic thiols described in Specification 579,353. The layer of liquid may also contain a photopolymerization catalyst, e.g. dimethyl alpha, alpha1 - azodiisobutyrate, or those described in Specifications 567,778 and 622,374. After the liquid has been converted to a solid it may be heat-treated, optionally in the presence of light. The solid layer may be cut into pieces and used in compression, injection or extrusion moulding. Specification 491,739 also is referred to.