Composition of epoxide resins, polycarboxylic acid anhydrides and polyester-dicarboxylic acids

A curable epoxide resin composition of epoxide resin, polycaboxylic acid anhydride and polyester-dicarboxylic acid, characterised in that it comprises

• a. at least 60 per cent by weight, based on the total amount of epoxide resin, of adducts, containing epoxide groups, of the formula I ##EQU1## wherein X.sub.1 and X.sub.2 each denote hydrogen or methyl and A denotes the radical, obtained by removal of the 1,2-epoxyethyl groups, of a diglycidyl compound, or wherein A together with X.sub.1 and/or X.sub.2 and with inclusion of the grouping ##EQU2## and/or ##EQU3## denotes the cycloaliphatic ring or the cycloaliphataic ring system of a partially reacted cycloaliphatic or cycloaliphatic-aliphatic diepoxide compound, B denotes a long-chain polyester radical consisting essentially of unsubstituted or substituted alkylene and/or alkenylene chains alternating with carboxylic acid ester groups, and the quotient Z/Q, wherein Z is the number of carbon atoms present in the recurring structural element of the radical B and Q is the number of oxygen bridges present in the recurring structural element of the radical B, has to be at least 4 and furthermore the total number of carbon atoms present in the radical B is at least 50,
• b. polycarboxylic acid anhydrides in an amount of 0.2-0.8 mol per 1 equivalent of epoxide group, and
• c. polyester-dicarboxylic acids of the formula II ##EQU4## wherein R.sub.1 and R.sub.2 denote divalent aliphatic, araliphatic, cycloaliphatic, cycloaliphatic-aliphatic, aromatic or heterocyclic-aliphatic radicals, wherein at least one of the two radicals R.sub.1 or R.sub.2 must contain a carbocyclic or heterocyclic ring or a carbocyclic or heterocyclic ring system and not more than 4 methylene groups are present per ring in the structural element of the formula ##EQU5## and n denotes a number from 1 to 30 in an amount of 0.8-0.2 equivalent of carboxyl groups per 1 equivalent of epoxide group.