The present invention relates to the thermoplastic polyesters, which
comprise, by weight
(i) a thermoplastic polyester;
(ii) an impact modifier comprising:
(a) a core-shelf copolymer (A);
(b) an ethylene copolymer (B) chosen from ethylene-unsaturated carboxylic
acid anhydride copolymers (B1), ethylene-saturated epoxide copolymers (B2)
and blends thereof;
(iii) the (B)/(A) ratio being between 90/10 and 25/75 for proportions of
impact modifier between 2 and 40% in 98 to 60% of polyester, respectively;
(iv) the (B)/(A) ratio being between 25/75 and 10/90 for proportions of
impact modifier between 18 and 40% in 82 to 60% of polyester,
respectively. It is particularly useful for PET and PBT.
