UNSATURATED POLYESTER-URETHANE PREPOLYMER AND ITS APPLICATIONS

An ethylenically unsaturated prepolymer comprising an ending X which reacts by condensation being a hydroxyl and/or amine or free isocyanate group and optionally an ending X' having ethylenic unsaturation, the prepolymer being the reaction product of a first component A comprising a mixture of i) a first ethylenically unsaturated resin carrying specific hydroxyl and/or amine reactive endings, and/or ii) optionally a second resin different from resin i), being an ethylenically unsaturated hydroxylated resin and/or a hydroxylated and/or aminated saturated resin, and/or iii) optionally a third reactive saturated resin, iv) optionally an unsaturated monoalcohol up to 30% in equivalents of the OH+NH2 total, and a second component B comprising a polyisocyanate with a functionality equal to 2 or greater than 2, A and B being in proportions to effectively avoid any gelling by crosslinking.