Elastomeric graft polymeres

A particulate elastomeric graft polymer which increases the impact strength of and at the same time performs the function of a dulling agent for macromolecular base materials B comprising B-1) polymers containing polymerized sytrene, methyl acrylate, C.sub.1 -C.sub.4 -alkyl methacrylate, acrylonitrile or methacrylonitrile or mixtures thereof, or

• B-2) impact-resistant styrene copolymers of ASA, ABS or AES or mixtures thereof, or
• B-3) polyesters, polyamides, polyvinyl chloride, polycarbonates or polyoxymethylene or mixtures thereof,
• or mixtures thereof
• and consists of a core K and one or more shells S, in which
• the particles of the particulate elastomeric graft copolymer have a mean particle diameter of from 1 to 150 .mu.m,
• the core K consists of a crosslinked elastomeric polymer P.sub.K,
• the outer shell S.sub.a is formed by a polymer P.sub.a which is compatible or partly compatible with the base material B and
• any further shells present may be composed of P.sub.K, P.sub.a or further polymers P.sub.x,
• obtained by
• a) dispersing the liquid monomer or liquid monomer mixture M.sub.K corresponding to the polymer P.sub.K in water using a protective colloid to give a dispersion of droplets having a mean diameter of from 1 to 100 .mu.m,
• b) polymerizing the droplets by means of a polymerization initiator to a conversion of more than 50%, based on the amount of M.sub.K, and
• c) subjecting the mixture obtained in stage b) to graft polymerization with sequential addition of the monomers or monomer mixtures M.sub.S corresponding to the graft shells S until the outer shell S.sub.a has been produced using the corresponding monomers M.sub.a.