ES265135A1 - Improvements in the production of vinyl chloride polymers - Google Patents

Abstract

A process for copolymerizing vinyl chloride with 0,1 to 30% (by weight of the total monomers) of a monoethylenically unsaturated acid, anhydride or acid chloride or partial ester of a monoethylenically unsaturated polycarboxylic acid comprises bulk polymerizing the monomers in the presence of a catalyst soluble in vinyl chloride, dispersing the partially polymerized mixture in water containing a dispersing agent while the mixture is still sufficiently fluid for this to be possible, and continuing the polymerization until the desired conversion is achieved. Acidic comonomers specified are acrylic, methacrylic, crotonic, maleic, fumaric, itaconic and aconitic acids, monoalkyl esters of maleic, fumaric and itaconic acids and monoand di-esters of aconitic acid. Up to 40% of a further monomer may also be present, e.g. acrylonitrile or vinyl formate, acetate, propionate or butyrate. Part of the faster polymerizing monomer may be added stepwise or continuously after commencement of polymerization, e.g. when the monomer mix contains vinyl acetate only half the vinyl chloride may be added initially and the remainder after dispersion in water. A chain transfer agent, e.g. chloroform or p tetrachloroethylene may be used to control the molecular weight. Catalysts specified are acetyl, lauroyl and succinyl peroxides, t-butyl hydroperoxide benzyl hyponitrite, alpha alpha1-bis (alpha gamma dimethyl valeronitrile) and dimethyl alpha alpha1-azodi-isobutyrate. Dispersing agents specified are gelatine, polyvinyl alcohol, starch, sodium alginate, methyl or glycol cellulose, and sodium cellulose glycollate. The bulk partial polymerisate may be cooled before it is dispersed in water or the water may be heated to polymerization temperature. It is preferred that the K-value of the copolymer be not less than 35. The copolymers have good adhesion to metals and these containing a third monomer, such as vinyl acetate, are soluble in organic solvents, e.g. methyl ethyl ketone. They may be used as heatsealable coatings on aluminium foil or as lacquers for beer tins and other metal articles.ALSO:A process for copolymerizing vinyl chloride with 0,1 to 30% (by weight of the total monomers) of a monoethylenically unsaturated acid, anhydride or acid chloride or partial ester of a monoethylenically unsaturated polycarboxylic acid comprises bulk polymerizing the monomers in the presence of a catalyst soluble in vinyl chloride, dispersing the partially polymerized mixture in water containing a dispersing agent while the mixture is still sufficiently fluid for this to be possible, and continuing the polymerization until the desired conversion is achieved. Acidic comonomers specified are acrylic, methacrylic, crotonic, maleic, fumaric, itaconic and aconitic acids, monoalkyl esters of maleic, fumaric and itaconic acids and mono- and di-esters of aconitic acid. Up to 40% of a further monomer may also be present, e.g. acrylonitrile or vinyl formate, acetate, propionate or butyrate. Part of the faster polymerizing monomer may be added stepwise or continuously after commencement of polymerization, e.g. when the monomer mix contains vinyl acetate only half the vinyl chloride may be added initially and the remainder after dispersion in water. A chain transfer agent, e.g. chloroform or tetrachloroethylene may be used to control the molecular weight. Catalysts specified are acetyl, lauroyl and succinyl peroxides, t-butyl hydroperoxide, benzyl hyponitrite, alpha alpha1-bis(alpha gamma dimethyl valeronitrile) and dimethyl alpha alpha1-azodi-isobutyrate. Dispersing agents specified are gelatine, polyvinyl alcohol, starch, sodium alginate, methyl or glycol cellulose, and sodium cellulose glycollate. The bulk partial polymerizate may be cooled before it is dispersed in water or the water may be heated to polymerization temperature. It is preferred that the K-value of the copolymer be not less than 35. The copolymers have good adhesion to metals and those containing a third monomer, such as vinyl acetate, are soluble in organic solvents, e.g. methyl ethyl ketone. They may be used as heat-sealable coatings on aluminium foil or as lacquers for beer tins.