Abstract: Cured polyester resin products having improved chemical resistance are prepared from a curable polyester resin comprising:A. an ethylenically unsaturated polyester having: a molecular weight of about 1,000 to about 4,000; an acid number of no greater than about 30; and a fumarate/maleate weight proportion of at least about 80%/20%, said polyester being the polyesterification reaction product of fumaric acid or maleic anhydride or mixture thereof and an acyclic glycol having a molecular weight of no greater than about 200 and an oxygen content of less than 42.6 wt. %; andB. a vinyl monomeric crosslinking agent in an amount such that the molar ratio of the ethylenic reactive unsaturation in said crosslinking agent to the ethylenic reactive unsaturation of said polyester is at least about 3 to 1, and wherein at least 50 wt.