Patent ID: 6767963
Filing Date: 2004-07-27
Classification: C08F

Abstract:
A thermoplastic molding composition containing a two-phase plastic that includes B) a thermoplastic copolymer forming a matrix as an external phase, produced from the resin forming vinyl monomers styrene and acrylonitrile, in which the styrene may wholly or partially be replaced by &agr;-methylstyrene or by methylmethacrylate, and A) at least one graft polymer produced by a grafting reaction of one or more of the monomers referred to in B) on a homopolymeric or copolymeric butadiene as a graft base, the graft polymer forming a dispersed phase in the matrix said A) being a product of a radical emulsion polymerization process wherein said resin forming vinyl monomers are polymerized in the presence of rubber in latex form having a glass transition temperature &lE;0Â° C., said polymerization initiated by a combination of a persulfate compound and at least one azo compound conforming to formula (III) where R denotes a member selected from the group consisting of CH3, C2H5, C3H7, C4H9, n-C3H7, i-C3H7, n-C4H9, i-C4H9, and t-C4H9, and wherein process comprise in sequencefeeding a first mixture that contains said azo compound and a first amount of monomers to said latex to form a reaction mixture, said first amount being 10 to 95 percent relative to the weight of the total amount of said monomers entailed in said polymerization, said azo compound being in an amount of 0.2 to 3 percent relative to the weight of said first amount, and introducing to the reaction mixture a second mixture that contains said persulfate compound and a second amount of monomers, said second amount being 5 to 90 percent relative to the weight of the total amount of said monomers entailed in said polymerization, the amount of said persulfate compound being 0.05 to 1.5 percent relative to the weight of said second amount.