Impact modifier combination for aromatic polyesters

A toughened blend consisting essentially of an aromatic polyester with from 5 to 20 parts, per 100 parts of polyester, of an impact modifier, which impact modifier is a blend of

• (a) 80 to 85 weight percent of a core/shell impact modifier having
• (1) from 70 to 90 parts of a core of a rubber which is a homopolymer of butadiene or a copolymer of butadiene with up to about 30% of at least one copolymerized vinyl monomer;
• (2) at least one shell, which shell is a homopolymer of methyl methacrylate or a copolymer which contains a majority of units derived from either methyl methacrylate or styrene;
• and
• (b) 15 to 20 weight percent of a linear copolymer which contains from 50 to 85 parts of units derived from ethylene, from 5 to 40 parts of units derived from a C.sub.1 -C.sub.8 ester of (meth)acrylic acid, and from 2 to 10 parts of a copolymerizable monomer containing an epoxy group;
• wherein the blend contains essentially no polycarbonate,
• and wherein the toughened blend exhibits higher impact strength, as measured by a notched Izod test, than would be calculated for the blend using a linear relationship based on values of notched Izod for two blends, each containing only one of the impact modifiers at an equal use level.