Thermoplastic block copolyesters, a process for the preparation thereof and their use for the production of mouldings

Claim 1

Block copolyesters having a relative viscosity (measured in phenol/o-dichlorobenzene, weight ratio of 1:1, at 25° C.) of from 1.15 to 3.0, which consist of the following, the terminal groups not being considered: (A) from 1 to 60% by weight, based on the block copolyester, of long-chain units of the following formula: ##STR5## (B) from 40 to 99% by weight, based on the block copolyester, of short-chain units of the following formula: ##STR6## characterised in that D represents a divalent polydiene radical containing at least 50 mol % of 1,4-bonds, terminal-positioned bonding points and having an average molecular weight M n of from 400 to 5000 and side chains which may optionally be present must be methyl and/or vinyl groups; G represents a divalent aliphatic radical having from 1 to 12 carbon atoms, and/or a divalent cycloaliphatic radical having from 6 to 12 carbon atoms with a molecular weight of less than 300, at least 70 mol % of G representing a uniform radical; S represents a direct bond or a divalent aliphatic, cycloaliphatic and/or aromatic radical having from 1 to 14 carbon atoms and having a molecular weight of less than 300, at least 70 mol % of S being 1,4-phenylene radicals.