Patent ID: 6878776

Claim:
A thermosetting composition comprising crosslinked polymer microparticles with a size of between 10 and 200 nm, wherein the microparticles are at least partially soluble, miscible and/or dispersible in the starting thermosetting composition and carry at least one first reactive functional group which can react with at least one reactive functional group carried by at least one reactive component of the thermosetting composition wherein the microparticles carry at least one functional group which reacts by a polycondensation reaction and at least one second functional group which is an α,β-ethylenic unsaturation which can polymerize by the radical route or by a specific Michael reaction and wherein the thermosetting composition comprises: a) at least one unsaturated polyester and/or at least one unsaturated polyester modified by a poly-isocyanate and/or at least one vinyl ester, b) at least one copolymerizable comonomer carrying at least one α,β-ethylenic unsaturation chosen from vinylaromatic and/or (meth)acrylic and/or allyl monomers, c) optionally at least one second monomer carrying at least two reactive functional groups, one of which can polymerize by the radical route and the other by a condensation reaction, d) 0.5-50% by weight of the said reactive crosslinked microparticles.