Thermoplastic moulding materials based on acrylonitrile, styrene and butadiene

摘要

The invention relates to thermoplastic molding materials based on acrylonitrile-butadiene-styrene, comprising a SAN-polymer matrix and a graft copolymer, structured from an agglomerated rubber-graft base and a SAN-graft envelope. The basis of the graft base is a diene rubber having a vinyl-aromatic ratio of 10.5 to 24.5 wt %. The agglomerated graft base has a bimodal particle size distribution of a fraction x) of non-agglomerated particles having a d50-value in the range from 80 to 120 nm and a fraction y) of agglomerated particles having a d50-value in the range of 350 to 550 nm and a polydispersity U of less than 0.28. The invention further relates to a method for producing the graft copolymer, wherein an acrylate copolymer having a polydispersity U of less than 0.27 and a d50-value of 100 to 150 nm is used for agglomeration. The invention further relates to the use of thermoplastic molding materials for producing molded parts.

主权项

1. A graft copolymer B constructed from:
B1: 40 to 85 wt %, based on the solids content of the graft copolymer B, of a graft substrate (B1) obtained by (a) polymerizing:
(B11): 10.5 to 24.5 wt %, based on the graft substrate B1, of at least one vinylaromatic, and(B12): 75.5 to 89.5 wt %, based on the graft substrate B1, of at least one diene,where (B11) and (B12) sum to 100 wt %; and (b) agglomerating the obtained graft substrate B1 by adding (C): 0.01 to 5 parts by weight, based on 100 parts by weight of the graft substrate B1, in each case based on the solids content, of an agglomerating copolymer (C) of:
(C1): 80 to 99.9 wt % of one or more C1 to C12 alkyl acrylates or C1 to C12 alkyl methacrylates and(C2): 0.1 to 20 wt % of one or more comonomers selected from the group consisting of acrylamide and methacrylamide,where (C1) and (C2) sum to 100 wt %; and B2: 15 to 60 wt %, based on the solids content of the graft copolymer B, of a graft sheath obtained by reacting the agglomerated graft substrate B1 with a mixture of:
(B21) 70 to 90 wt %, based on the graft sheath (B2), of styrene and/or α-methylstyrene, and(B22) 10 to 30 wt %, based on the graft sheath (B2), of acrylonitrile and/or methyl methacrylate, where the graft substrate B1 and the graft sheath B2 sum to 100 wt % in total; and where (i) the agglomerating copolymer (C) has a polydispersity U in the range of from 0.26 to 0.20 and a d50 value in the range of from 110 to 140 nm; and (ii) the agglomerated graft substrate B1 has a bimodal particle size distribution of a fraction x) of nonagglomerated particles having a d50 value in the range of from 80 to 120 nm and a fraction y) of agglomerated particles having a d50 value in the range of from 350 to 450 nm and a polydispersity U in the range of from 0.27 to 0.20.