| 摘要 |
1277877 Acrylic emulsions DUNLOP HOLDINGS Ltd 20 Aug 1969 [20 Aug 1968] 39671/68 Heading C3P Aqueous acrylic emulsions comprise an acrylic resin containing at least 20% by wt. of polymerized acrylic or methacrylic acid ester units, at least one emulsifying agent, a mercaptan, and a carboxyl containing colloid in an amount of at least 0À1% by weight of the emulsion. The carboxyl-containing colloid is defined as being water-miscible, self-water dispersible or water swellable, should be soluble in an alkali, and the carboxyl groups may be in their salt form. Acrylic and methacrylic esters specified are methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate and 2-ethyl hexyl acrylate. Units of other monomers such as styrene, alpha-methyl styrene, vinyl toluene, itaconic acid, methacrylic acid or acrylic acid, may also be present in the acrylic resin. The emulsifying agent may comprise a non-ionic and an ionic emulsifying agent and examples given of these are (a) polyoxyethylene ethers and (b) salts of organo phosphate or phosphonate esters and salts of organo sulphate or sulphonate esters such as Na lauryl sulphate, and Na dodecylbenzene sulphonate. The preferred mercaptan is tert.-dodecyl mercaptan. The colloid may be formed by the polymerization of an unsaturated acid in which there are two carboxyl groups attached to carbon atoms on either side of the unsaturated bond, preferably polymerized with a comonomer. The particular colloids specified are a 1: 1 by weight ethylene/maleic anhydride copolymer, and polyacrylic and polymethacrylic acids. The composition may also contain a pigment which may be corrosion-inhibiting, such as zinc tetroxy chromate, zinc molybdate, strontium chromate, lead silicachromate or coprecipitated zinc phosphate/zinc chromate. Examples relate to emulsions produced by emulsion polymerization in the presence of the above specified colloids and mercaptan and emulsifying agents, of butyl acrylate/methyl methacrylate/methacrylic acid, and methacrylic acid / styrene / methyl methacrylate / butyl acrylate. A pigmented composition is prepared in Examples II and IV. |
