Improvements in or relating to the preparation of aqueous emulsions of polyvinyl acetate or vinyl acetate copolymers

摘要

An aqueous emulsion of a vinyl acetate polymer or copolymer is made by polymerization in aqueous dispersion in the presence of a substance or substances yielding the anion:- where R is a hydrogen atom or methyl radical. The cations associated with the above divalent anion may be the same or different and may be hydrogen, alkali metal, ammonium or substituted ammonium ions and the substance is preferably the monoallyl ester of disodium or diammonium sulphosuccinate. The polymerization may be conducted in the presence of a free radical catalyst, e.g. a persulphate at an elevated temperature with the monomer being added during the polymerization. Further surfactants and stabilizers, e.g. polyvinyl alcohol, or sodium dodecyl benzene sulphoxate, chain transfer agents, e.g. C Cl4, solvents, plasticizers, e.g. acetyl tributyl citrate, pH adjusters and salts may also be present. The vinyl acetate may be copolymerized with alkyl maleates, fumarates, itaconates or acrylates, other vinyl esters such as vinyl propionate, stearate, benzoate or crotonate, isopropenyl esters of carboxylic acids, vinyl chloride, vinylidene chloride, crotonic, itaconic or acrylic acids or acrylonitrile.ALSO:Monoallyl or monomethallyl esters of dialkali metal or diammonium sulphosuccinates may be prepared by esterifying maleic anhydride with allyl or methallyl alcohol to form the monoester, and reacting the monoester with an alkali metal or ammonium sulphite. In examples maleic anhydride is esterified with allyl alcohol and the products reacted with (1) sodium sulphite and (2) ammonium sulphite.