GB1015334A - Process for making polymeric materials derived from vinyl chloride and other monomers - Google Patents

Abstract

Polymeric compositions are obtained by a polymerization process comprising the steps of: (1) forming an aqueous slurry of a vinyl polymer made by polymerizing vinyl chloride together with 0 to 40% by weight, based on the weight of the vinyl polymer, or one or more ethylenically unsaturated monomers copolymerizable therewith, said vinyl polymer being capable of totally absorbing the monomeric component used in step (2); (2) adding to said slurry from 25 to 60% by weight of a monomeric component, based on the weight of the vinyl polymer and monomeric component, said monomeric component comprising at least one monoethylenically unsaturated polymerizable monomer, and allowing the monomer to be absorbed by the polymer; and (3) maintaining the monomer in the presence of a sufficient quantity of a free radical yielding catalyst and at a temperature at which the catalyst is catalytically active to effect polymerization of the monomer. The vinyl polymer may be a vinyl chloride homopolymer or a copolymer of vinyl chloride with vinyl acetate or vinyl idene chloride. The monomeric component added in step (2) preferably comprises an alkyl acrylate or methacrylate in which the alkyl radical contains 1 to 12 or 1 to 10 carbon atoms respectively, styrene, a halogen-substituted styrene, and a -alkyl-styrene in which the alkyl radical contains 1 to 3 carbon atoms or acrylonitrile; other suitable monomers include maleimide and N-alkyl- and N-aryl-maleimides, e.g. N-phenyl-maleimide and derivatives thereof wherein the phenyl group is substituted by halogen or a nitro or nitrile group, or an alkyl or alkoxy group containing 1 to 4 carbon atoms. The monomeric component may also include one or more cross-linking agents, e.g. glycol dimethacrylate, divinyl benzene, vinyl methacrylate, methylene dimethacrylate, allyl methacrylate, diallyl phthalate, diallyl maleaIe, allyl acrylate, methallyl acrylate, butadiene-1,3, isoprene and 2-chlorobutadiene. The monomeric material may be added to the slurry all at once or may be added in increments during the course of polymerization; in the latter case the material added in a later increment may be wholly or partly different from that added earlier. The catalyst employed may be an azo compound, e.g. a ,a 1-azodiisobutyronitrile, the methyl, ethyl or n-butyl ester of a ,a 1-azodiisobutyric acid, a ,a 1 - azodi - a ,g - dimethyl valeronitrile or a ,a 1-azodicyclohexane carbonitrile, or a peroxide, e.g. benzoyl peroxide or lauroyl peroxide. Other ingredients may also be included in the polymerization mixture such as chain transfer agents, e.g. lauryl mercaptan and tert-dodecyl mercaptan; lubricants, e.g. stearyl alcohol, stearic acid, cetyl palmitate, ethyl palmitate, cetyl alcohol, magnesium stearate and calcium stearate; and heat stabilizers such as organotin compounds or barium, lead or cadmium compounds, e.g. dioctyl tin dinonyl dithio glycollate.