GB1005377A - Aqueous emulsions of acrylic ester copolymers - Google Patents

Abstract

Aqueous copolymer emulsions are obtained by polymerizing, in aqueous emulsion or dispersion, a monomer mixture comprising at least 15% by weight of one or more acrylate esters of the formula CH2=CH-COOR where R is an alkyl group containing from 1 to 10 carbon atoms or a substituted alkyl group containing from 1 to 12 carbon atoms; 0.02 to 5.0% by weight of a substance capable of yielding in aqueous solution an anion of the formula <FORM:1005377/C3/1> where R1 is hydrogen or a methyl group; the remainder, if any, of the monomer mixture being one or more ethylenically unsaturated monomers copolymerizable with the other components. Where the aforementioned acrylate ester comprises a substituted alkyl group, the substituent may be an aryl, carboalkoxy, hydroxy, cyano, halo, nitro, amido, amino, aryloxy, alkoxy or polyalkoxy group. The substance yielding the specified anion is generally an alkali metal or ammonium salt of mono-allyl or mono-methallyl sulphosuccinate. Optional comonomers include vinyl esters; alkyl a -substituted acrylates; acrylonitrile and methacrylonitrile; styrene and substituted styrene; vinyl chloride and vinylidene chloride; acrylamide and methacrylamide; ethylenically unsaturated carboxylic acids, such as acrylic, methacrylic and itaconic acids; and mono- and di-alkyl itaconates, maleates and fumarates. The polymerization is effected with the aid of initiators such as salts of perdisulphuric acid, e.g. ammonium persulphate, organic peroxides or hydroperoxides, hydrogen peroxide, and azo compounds such as azo diisobutyronitrile; these can be used in conjunction with reducing agents such as sulphites and bisulphites, sulphoxylates, polyamines and ferrous iron complexes. Conventional anionic or non-ionic surfactants or emulsifiers may be used for the emulsion polymerization process. Other ingredients which may be present are electrolytes, pH adjusters, sequestering agents for polyvalent metal-ions, plasticizers, solvents and molecular weight modifiers. The monomers used may be added in portions or continuously during polymerization in order to obtain better control of the reaction and of the copolymer particle size. Films and laminar articles can be cast from the copolymer emulsions. Examples describe the preparation of emulsions of copolymers of disodium allyl sulphosuccinate with (i) n-butyl acrylate, acrylonitrile and acrylic acid, (ii) n-butyl acrylate and acrylic acid, (iii) n-butyl acrylate, (iv) 2-ethylhexyl acrylate and acrylic acid, (v) n-butyl acrylate, styrene and acrylic acid, (vi) n-butyl acrylate, methyl methacrylate and acrylic acid, (vii) n-butyl acrylate, vinyl acetate and acrylic acid.ALSO:Salts of monoallyl or monomethallyl sulphosuccinates are prepared by esterifying maleic anhydride with one, or a little more than one, molecular proportion of allyl or methallyl alcohol and then adding to the monoester an aqueous solution of a bisulphite or sulphite, e.g. an alkali metal or ammonium bisulphite or sulphite. An example describes the preparation of disodium allyl sulphosuccinate. The salts are used in the preparation of emulsion copolymers (see Division C3).