Copolymers of para-alpha dimethylstyrene and thermoplastic compositions
A thermoplastic copolymer prepared from acrylonitrile and para-alpha-dimethylstyrene via bulk or solution polymerization has an improved heat distortion temperature and can be used together with graft copolymers and further components for the preparation of thermoplastic moldings.
1. A thermoplastic copolymer (A) which comprises:
A1: from 38 to 58 mol-percent, based on the copolymer, of at least one of the monomers from the group consisting of acrylonitrile, acrylate, methacrylate and N-phenyl-maleic imide; and
A2: from 42 to 62 mol-percent, based on the copolymer, of a mixture of para-alpha-dimethylstyrene with alpha-methylstyrene, whereby the weight ratio of the components para-alpha-dimethylstyrene and alpha-methyl-styrene is between 1 to 4 and 4 to 1.
2. The thermoplastic copolymer (A) according to claim 1 , wherein the component A1 is acrylonitrile, C 1 -C 12 -alkyl-acrylate, C 1 -C 12 -methalkyl-acrylate or N-phenyl-maleic imide.
3. The thermoplastic copolymer (A) according to claim 1 , which comprises from 42 to 54 mol-percent of the component A1 which is acrylonitrile or N-phenyl-maleic imide, and which comprises from 46 to 58 mol-percent of the component A2, which contains para-alpha-dimethylstyrene and alpha-methylstyrene.
4. The thermoplastic copolymer (A) according to claim 1 , which is composed of 48 to 58 mol-percent of the monomer para-alpha-dimethylstyrene and of 42 to 52 mol-percent of acrylonitrile.
5. A thermoplastic molding composition comprising a thermoplastic copolymer (A) which comprises:
A1: from 38 to 58 mol-percent, based on the copolymer, of at least one of the monomers from the group consisting of acrylonitrile, acrylate, methacrylate and N-phenyl-maleic imide; and
A2: from 42 to 62 mol-percent, based on the copolymer, of para-alpha-dimethylstyrene or of a mixture of para-alpha-dimethylstyrene with other styrene-derivatives having 9 or 10 carbon atoms,
a graft copolymer (B) and as further component (K), one or more components selected from the group of a dispersing agent (DA), a buffer substance (BS), a molecular weight regulator (MR), a filler (F), and an additive (D).
6. The thermoplastic molding composition according to claim 5 , wherein the graft copolymer (B) is an ABS copolymer.
7. The thermoplastic molding composition according to claim 5 , wherein the further component is at least one further thermoplastic polymer (TP) selected from the group consisting of an ABS-copolymer, a SAN-copolymer, a polycarbonate, a polyester carbonate, a polyester and a polyamide.
8. A molding, produced from at least one thermoplastic molding composition containing the thermoplastic copolymer (A) according to claim 1 .
9. A process for preparation of the thermoplastic copolymer (A) as claimed in claim 1 , which comprises the step of bulk polymerization, emulsion polymerization or solution polymerization of para-alpha-dimethylstyrene and other styrene-derivatives with monomers from the group comprising acrylonitrile, acrylate, methacrylate and N-phenyl-maleic imide.
10. The process according to claim 9 , comprising the step of bulk polymerization or solution polymerization of a mixture comprising para-alpha-dimethylstyrene and acrylonitrile.
11. The process according to claim 9 , which comprises preparing the thermoplastic copolymer (A) via bulk polymerization, emulsion polymerization or solution polymerization, preparing a graft copolymer (B), and then mixing the thermoplastic copolymer (A) and the graft copolymer (B), and optionally a further component (K) and/or a further thermoplastic polymers (TP).