GB804448A - Polymerisation of vinyl halides - Google Patents

Abstract

Polymers and copolymers of vinyl halides containing a halogen having an atomic number not exceeding 35, are made by polymerization in aqueous dispersion in the presence of (1) an interpolymer of ethylene and maleic anhydride of specific viscosity at least 1.1, determined in 1 per cent dimethylformamide solution at 25 DEG C.; or (2) an interpolymer of ethylene and maleic acid obtainable by hydrolysis of an interpolymer under (1); or (3) a partial ester of an interpolymer under (1) or (2) having up to 15 mol. per cent of the carboxyl and/or anhydride groups esterified with a monohydric acyclic, carbocyclic or heterocyclic alcohol or a monohydric phenol containing up to 10 carbon atoms which is free from groups, other than hydroxyl groups, which will react with a carboxyl or carboxylic anhydride group and does not constitute more than 20 per cent by weight of the molecule of the partial ester, all of said interpolymers being free from salt groups. The vinyl halide may be vinyl fluoride, chloride or bromide and copolymers may be made with vinyl acetate, propionate, butyrate or benzoate or methyl, ethyl, butyl or allyl acrylates or methacrylates or acrylamide, acrylanilide, acrylonitrile, vinylidene chloride, trichloroethylene or the methyl, ethyl, propyl, butyl, amyl, hexyl, heptyl, octyl, allyl or methallyl esters of maleic, citraconic, itaconic or fumaric acids. The ethylenemaleic interpolymers may be made by heating maleic acid or anhydride in an aromatic solvent, e.g. benzene, with ethylene under pressure and in the presence of a catalyst. The maleic interpolymer may be partially esterified after polymerization or partially esterified maleic acid or anhydride may be used in the polymerization or the esterification may take place simultaneously with the polymerization. The interpolymers usually contain substantially equimolar proportions of ethylene and the maleic constituent. The monohydric alcohol may be methanol, ethanol, isopropanol, n-propanol, methoxyethanol, n-butanol, n-hexanol, octanol, n-decanol, cyclopentanol, cyclohexanol, phenol, cresol, xylenol or tetrahydrofurfuryl alcohol. In the vinyl halide polymerization there may be present in addition to the maleic-ethylene interpolymers particle size reducing agents such as unsaturated aliphatic carboxylic acids having 10 to 20 carbon atoms or their halogen-substituted derivatives, hydroxyl-substituted aliphatic carboxylic acids having 10 to 20 carbon atoms or partial esters of polyhydric alcohols having 2 to 8 carbon atoms with aliphatic carboxylic acids having 10 to 20 carbon atoms, e.g. glyceryl mono-octadecanoate. There may also be present during the polymerization plasticizers such as dialkyl phthalates in which the alkyl groups contain 2 to 10 carbon atoms, e.g. dibutyl phthalate, esters of glycols containing not more than 10 carbon atoms with fatty acids containing 2 to 9 carbon atoms or phosphoric acid esters of phenol, the cresols and the xylenols and there may be used as catalysts benzoyl, lauroyl, ditertiary butyl, oleyl or toluyl peroxides.