GB1243786A - Improved copolymers - Google Patents

Abstract

1,243,786. Grafted acrylic elastomers. UGINE KUHLMANN. 7 Jan., 1969 [9 Jan., 1968; 21 Aug., 1968], No. 1047/69. Heading C3G. A graft polymer is obtained by polymerizing, in an emulsion, 15 to 90 parts by weight of a mixture of monomers A + B and optionally C comprising: (A) at least one vinyl or vinylidene aromatic monomer in a proportion equal to or greater than 60% by weight of A + B; (B) at least one ethylenic nitrile in the proportion of up to 40% of A + B; and C) one or more comonomers in the proportion of 0 to 30% of A + B, in the presence cf 85 to 10 parts of an elastomer, in latex form, obtained by successive polymerization, in an emulsion, in a first stage of 40 to 95 parts by weight of a mixture of (a) at least one C 1 to C 8 -alkyl acrylate in the proportion of 70 to 99À99% by weight cf a + b + c; (b) one or more comonomers in the proportion of 0 to 29À99% of a + b + c; and (c) one or more monomers having at least 2 polymerizable double bonds in the proportion of 0À01 to 2% of a + b + c and, in the second stage, of 60 to 5 parts of a mixture of (d) at least one C 1 -C 8 -alkyl acrylate in the proportion of 50 to 98% by weight of d + e + f + g; (e) at least one ester corresponding to the formula in which R 1 and R 2 represent a hydrogen atom or methyl group, in the proportion of 2 to 30% of d + e + f + g; (f) one or more comonomers in the proportion of 0 to 30% of d + e + f + g; and (g) one or more monomers having at least 2 polymerizable double bonds in the proportion of 0 to 2% of d + e + f + g. Specified monomers (c) and (g) are allyl acrylate or methacrylate, ethylene glycol diacrylate or dimethacrylate and divinyl benzene. Monomer (e) may be tetrahydrobenzyl acrylate or methacrylate. The graft polymer may be mixed with a resin based on styrene, alpha-methyl styrene, acrylonitrile or methyl methacrylate. In the examples, styrene and acrylonitrile are grafted on to an elastomer obtained by the polymerization in two stages of a mixture comprising n-butyl acrylate and ethylene glycol dimethacrylate, or n-heptyl acrylate, ethyl acrylate and divinyl benzene, tetrahydrobenzyl acrylate being present in the second stage of the polymerization. The graft polymers latices produced are co-coagulated with a styrene-acrylonitrile resin latex.