Abstract: The present invention relates to a thermosetting resin composition comprising (A) An unsaturated polyester resin comprising fumaric acid building blocks and/or a methacrylate functional resin, whereby the resin has a molecular weight Mn of from 450 up to and including 10000 Dalton and the amount of such unsaturated polyester resin and methacrylate functional resin is from 30 up to and including 80 wt. %; (B) An ethylenically unsaturated compound copolymerizable with (A); present in an amount from 10 up to and including 60 wt. %; (C) A core-shell rubber in an amount from 0.1 up to 6 wt. %, whereby the core has a Tg of less than ?30° C. and the average particle diameter of the core-shell rubber is from 50 up to and including 1000 nm; and (D) An epoxy compound in an amount from 0.3 up to and including 10 wt. %; whereby the amounts are given relative to the total weight (in g) of the summed amount of (A), (B), (C) and (D).