GB753322A - Styrene copolymer emulsions - Google Patents

Abstract

Styrene is copolymerized with at least two polymerizable esters of ethylenic carboxylic acids of 3 to 5 carbon atoms and having at least two hydrogen atoms attached to the ethylenically linked carbon atoms, the copolymerization being in emulsion in an aqueous solution of one or more hydrophilic colloids and in the presence of one or more plasticizers, one or more free radical catalysts and one or more surface-active agents. Esters specified are the alkyl and substituted alkyl esters of acrylic, methacrylic, crotonic, 2-chloroacrylic and maleic acids, as exemplified by methyl and butyl methacrylates and di-(ethyl hexyl) maleate. The colloids may be the alkali metal and ammonium salts of polyacrylic and polymethacrylic acids, of styrene copolymers with acrylic and/or methacrylic acids, of copolymers of acrylic and/or methacrylic acid esters with acrylic and/or methacrylic acids, and of styrene-maleic acid copolymers; the water soluble ethers of cellulose and starch; degraded starch; dextrin; pectin; salts of carboxy methyl cellulose; and gums such as arabic and tragacanth. Plasticizers listed are chlorinated diphenyls; tricresyl and tributyl phosphates; di-butyl, dioctyl, di-butoxy-ethyl and butyl benzyl phthalates and tri-ethyleneglycol hexoate. Catalysts disclosed are hydrogen, benzoyl and di-t.-butyl peroxides, cumene hydroperoxide and potassium persulphate. A number of conventional surface-active agents are listed. Molecular weight regulators such as carbon tetrachloride, chloroform, bromoform and hexachloroethane may be used and the rate of radical formation of the catalyst may be adjusted with compounds such as ferrous compounds, hydrazine hydrate, sulphoxylates, sulphites, cane sugar, glucose, dodecyl mercaptan, diisopropyl xanthogen disulphide, mercaptobenzthiazyl disulphide, mercaptobenzthiazol, zinc isopropyl zanthate, cyclohexyl amine, ammonium diethyl dithiocarbamate and formic acid or its salts. Other materials included in the examples are hydroquinone and ammonia. The reaction mixture may be replenished by continuous or intermittent addition of any or all of the components as is illustrated in the examples. The products are of particle size less than 2 microns and are useful in emulsion paints, coating compositions, adhesives and in impregnants for porous materials.