Polyesters which contain maleate groups

摘要

The production is described of unsaturated polyesters, which exclusively contain maleate groups in their main chain, by the ring-opening polymerisation of epoxides, such as glycidyl ethers, glycidyl esters and olefine epoxides, with alpha , beta -unsaturated anhydrides, preferably such as maleic anhydride, both on their own and in admixture with other cyclic anhydrides, in the presence of a Zn<2+> carboxylate. The polyesters which are thus produced are characterised by high molecular weights and a narrow molecular weight distribution. Polymerisation can be effected between 50 and 120 DEG C, but is preferably effected between 60 and 90 DEG C, either in the melt or in a solvent. Unsaturated reactive thinners, which after the addition of suitable radical initiators react thermally or photochemically with the polyesters to form lacquers, cast parts or fibre-reinforced composite materials, can also be employed as solvents. The preferred crosslinking agents for the polyesters are mono- and polyfunctional acrylates, methacrylates, vinyl ethers and vinyl esters. The polyesters can also be completely or partially isomerised, either thermally or by catalysis, to form polyesters which comprise fumarate groups in their main chain.