Vinyl ester resins prepared from urethane modified epoxy resin compositions containing oxazolidinone or thiazolidinone groups

A polymer modified vinyl ester composition comprising the reaction product of

• (A) at least one polymer modified epoxy resin resulting from polymerizing at least one polymerizable ethylenically unsaturated compound or mixture of such compounds with at least one urethane oligomer modified epoxy resin which comprises the reaction product of
• (1) at least one epoxy resin with
• (2) at least one urethane oligomer containing at least one oxyalkylene group or thioalkylene group and both polymerizable ethylenically unsaturated and isocyanate or isothiocyanate groups in the presence of
• (3) a catalyst for oxazolidinone or thiazolidinone formation;
• and wherein components (1) and (2) are present in quantities such that from about 0.001 to about 25 percent of the epoxide groups of components (1) are converted to oxazolidinone (thiazolidinone) groups and component (3) is employed in an amount sufficient to cause reaction of component (1) with component (2) to form oxazolidinone (thiazolidinone) groups, preferably from about 0.01 to about 3 parts of component (3) by weight based on the combined weight of components (1), (2) and (3);
• (B) at least one member selected from
• (1) at least one polymerzable ethylenically unsaturated monocarboxylic acid,
• (2) at least one polymerizable ethylenically unsaturated half-ester of a dicarboxylic acid, or
• (3) a combination of (B-1) and (B-2).