Patent GB-928251-A (GB)
IPC: C08F220/06
Abstract: 928,251. Emulsion polymerization. A. E. STALEY MANUFACTURING CO. Aug. 15, 1961 [Aug. 29, 1960], No. 29390/61. Class 2(6) Interpolymer emulsions by polymerizing in aqueous emulsion in the presence of a freeradical catalyst (A) at least one C 1 -C 8  alkyl acrylate or C 4 -C 12  alkyl methacrylate, (B) at least one monomer selected from styrene, ring- substituted styrenes and mixtures thereof with a C 1 -C 3  alkyl methacrylate,. and (C) an unsaturated acid of the formula: wherein R 2  may be H, a C 1 -C 6  alkyl group, CH 2 -COOH or CH 2 -COOR 3 , R 3  being a C 1 -C 8  alkyl group, in proportions such that 95, to 99À5 % by weight of the interpolymer is monomers (A) and (B) in a weight ratio of 2:8 to 7:3, the interpolymerization being carried out in one stage involving at least 70 % by weight of the entire proportion of monomer (A) and up to 70 % by weight of monomer (B) and in a second stage in the same polymerization medium in which there is used the balance of monomer (B) and any balance of monomer (A), at least one of the stages including at least part of monomer (C) and in the other stage any balance of monomer (C). As additional monomeric material there may be used cross-linking monomers, e.g. divinyl benzene, diallyl itaconate and polyethylene glycol dimethacrylate, and C 9 -C 18  alkyl acrylates and C 13 -C 18  alkyl methacrylates, such monomers being used in an amount of up to 5% of the other monomers. As polymerization catalysts there are specified hydrogen peroxide, alkali metal and ammonium persulphates, perborates, benzoyl, caproyl and methyl ethyl ketone peroxides, tert.-butyl, cumene and diisopropyl benzene hydroperoxides, azo catalysts and redox systems employing ascorbic acid, sulphites, bisulphites, hydrosulphites, sulphoxylates, thiosulphates and ferrous ions. As emulsifiers there may be used alkali metal and ammonium salts of long-chain sulphates and non-ionic emulsifiers. The examples describe the polymerization of the following monomer combinations: (a) styrene, ethyl acrylate and either acrylic, methacrylic or itaconic acid or monobutyl itaconate; (b) styrene butyl acrylate and methacrylic acid; (c) styrene, 2-ethylhexyl acrylate and methacrylic acid; (d) styrene, methyl acrylate, butyl acrylate and methacrylic acid; (e) styrene, ethyl acrylate, butyl or 2-ethylhexyl acrylate and methacrylic acid; ( f ) styrene, methyl methacrylate, 2-ethylhexyl acrylate and methacrylic acid; (g) styrene, butyl acrylate and methacrylate and methacrylic acid; (h) styrene butyl acrylate, hexyl methacrylate and methacrylic acid; (i) styrene, ethyl acrylate, decyloctyl methacrylate and methacrylic acid; (j) styrene, vinylethyl benzene, vinyl diethyl benzene, divinyl benzene, ethyl acrylate and methacrylic acid; and (k) vinyl toluene, ethyl acrylate and methacrylic acid. The resulting emulsion may be neutralized and compounded with pigments to form paints. In Example 2 an interpolymer emulsion formed from styrene, ethyl acrylate and methacrylic acid is neutralized with ammonia and then mixed with a pigment composition consisting of water, titanium dioxide, lecithin, casein, tributoxyethyl phosphate, an alkali metal salt of a polyelectrolyte and a preservative.