Abstract: The invention relates to improved polyacetal compositions composed of polyoxymethylene (component A) and a stabilized MBS core shell graft copolymer (component B) formed from a rubber-elastic core based on polybutadiene, and a hard graft shell.The stabilized MBS core shell graft copolymer (component B) contains a special stabilization formulation of at least one hindered phenol, a phosphite, a sulfide, and a pH buffer system.The shaped articles produced from these mixtures are particularly distinguished by an excellent low-temperature impact strength and a good heat aging performance.

Abstract: Syndiotactic polystyrene can be impact-modified by a blend of (a) polystyrene-hydrogenated polybutadiene block copolymers and (b) one or more core/shell modifiers based on a lightly or non-crosslinked rubber core, and with at least one shell or intermediate shell stage which is predominantly polystyrene, to produce a material of higher impact strength than the better value of either additive singly at the same total impact modifier level.