| abstract |
1340179 Graft polymers E I DU PONT DE NEMOURS & CO 20 May 1971 [25 Nov 1970] 27150/73 Divided out of 1339930 Heading C3G A graft polymer comprises (A) a backbone copolymer of (1) 0À1 to 20%, by weight of the graft polymer, of a C 4 to C 7 -cyclic carboxylic acid anhydride and (2) at least one comonomer selected from styrene, a substituted styrene, a C 3 to C 30 -vinyl ether, allyl alcohol and an ether of structure CH 2 =CH-CH 2 OR (where R is a C 1 to C 24 -alkyl radical) and (B) a graft component which is a polymer or copolymer of ethylenically unsaturated monomer(s) and has an average solubility parameter of 7À5 to 9. The graft monomer of (B) is preferably a C 1 to C 24 -alkyl (meth) acrylate or a vinyl ester of a C 3 to C 36 - carboxylic acid. The graft polymers are used for dispersing pigments, e.g. magnetic oxides in organic liquids, e.g. acrylic lacquers. In an example, methyl methacrylate and 2-ethylhexyl acrylate are grafted on to maleic anhydride/styrene copolymer, the resulting solution in ethyl acetate being blended with hydrous ferrous oxide and hot milled to yield a polymer/ oxide mixture which is dissolved in xylene/ naphtha and added to a lacquer. Maleic anhydride may be replaced by itaconic anhydride and other graft monomers are specified. |