Thermosetting epoxy resin composition having low curing temperature and good storage stability

A thermosetting epoxy resin composition comprising

• a) at least one epoxy resin A having an average of more than one epoxy group per molecule;
• b) at least one curing agent B for epoxy resins, where the curing agent B is a dihydrazide selected from the group consisting of glutaric dihydrazide, adipic dihydrazide and pimelic dihydrazide;
• and
• c) at least one accelerator C of the formula (Ia) or (Ib)
• where R1 is H or an n-valent aliphatic, cycloaliphatic or araliphatic radical;
• R2 and R3 are
• either
• each independently an alkyl group or aralkyl group;
• or
• together are a divalent aliphatic radical which has 3 to 20 carbon atoms and is part of an optionally substituted heterocyclic ring having 5 to 8 ring atoms;
• R1′ is an n′-valent aliphatic, cycloaliphatic or araliphatic radical;
• R2′ is an alkyl group or aralkyl group or alkylene group;
• R3′ is independently H or an alkyl group or aralkyl group;
• and
• n and n′ each have a value of 1 to 4,
• wherein when R1 is not H, R1 does not include an aromatic group bonded directly to a nitrogen atom of Formula (Ia),
• wherein a ratio of a proportion of epoxy groups of the epoxy resin A in a mol/a proportion of dihydrazide in mol is 3-5,
• wherein a ratio of a proportion of accelerator C in grams per mole of epoxy groups of the epoxy resin A is 0.08-0.15 g/mol of epoxy groups, and
• wherein the epoxy resin composition has a viscosity at 25° C. of 500 to 3000 Pa*s.