Thermoplastic polyester moulding compositions having improved toughness

Thermoplastic polyester moulding composition of (A) from 65 to 99% by weight, based on component (A) plus (B), of a saturated polyester of an aromatic dicarboxylic acid and an aliphatic or cycloaliphatic diol and

• (B) from 1 to 35% by weight, based on components (A) plus (B), of a graft product consisting of
• (I) from 5 to 55% by weight, based on components (I) and (II), of at least one monomer selected from the group consisting of styrene, acrylonitrile and methyl methacrylate grafted on
• (II) from 45 to 95% by weight, based on components (I) and (II) of an elastomer as a graft base characterized in that the elastomer (II) is obtained by the cross-linking copolymerization of a mixture consisting of from 99.01 to 99.95% by weight, based on elastomer (II) of an acrylic ester of a C.sub.1 -C.sub.8 -alcohol and from 0.05 to 0.99% by weight, based on elastomer (II) of a cyclic monomeric compound selected from the group consisting of triallyl cyanurate and triallyl isocyanurate.