Patent ID: 6162867
Filing Date: 2000-12-19
Classification: C08L,Y10S

Abstract:
A thermoplastic molding composition comprisingA) from 30 to 98% by weight of a graft copolymer comprisinga.sub.K) from 30 to 90% by weight of an elastomeric graft core, obtained by copolymerization ofa.sub.K /1)from 80 to 99.99% by weight of one or more C.sub.1 -C.sub.10 -alkyl acrylates,a.sub.K /2)from 0.01 to 20% by weight of a monomer with crosslinking effect, anda.sub.K /3)from 0 to 40% by weight of one or more other monomers,a.sub.S) from 10 to 70% by weight of a graft shell comprisinga.sub.S /1)from 50 to 100% by weight of a styrene compound of the formula ##STR5## where R.sup.1 and R.sup.2 are hydrogen or C.sub.1 -C.sub.8 -alkyl, or a C.sub.1 -C.sub.8 -alkyl acrylate or methacrylate,or a mixture of the styrene compound and the C.sub.1 -C.sub.8 -alkyl acrylate or methacrylate, anda.sub.S /2) from 0 to 50% by weight of one or more other monomers,B) from 1 to 50% by weight of a thermoplastic polymer comprisingb.sub.1) from 50 to 100% by weight of styrene or .alpha.-methylstyrene or mixtures of theseb.sub.2) from 0 to 50% by weight of acrylonitrile, andb.sub.3) from 0 to 50% by weight of one or more other monomers, andC) from 1 to 70% by weight of an elastomeric block copolymer prepared byanionic polymerization of the monomers with addition of a potassium compound soluble in non-polar solvents (Step 1)followed by hydrogenation of all or virtually all the olefinic double bonds of the polymer obtained in Step 1) (Step 2),which essentially consists ofat least one block A, which forms a hard phase and contains, in its polymer chain, units of a vinylaromatic monomer,or a block B, which forms a first elastomeric (soft) phase and contains diene monomers,or block A and block B,and at least one elastomeric block B/A, which forms a (if appropriate second or further) soft phase, and contains, randomly in its polymer chain, units of both a vinylaromatic monomer and a diene,where the glass transition temperature T.sub.g of the block A is above 25.degree. C. and that of the block B/A, before hydrogenation, is below 25.degree. C. and the phase-volume ratio of block A to block B/A is chosen so that the proportion of the hard phase in the entire block copolymer is from 1 to 40% by volume and the proportion by weight of the diene is less than 50% by weight.