Acrylate groups Urethane groups

(CH2 = CH- COO-R'-O-CO-N-R-H-NHCOO) R''n > 2

The hydroxyl groups, derived from acrylate and methacrylate, can easily react with the -NCO groups and form a stable urethane bond at room temperature.Acrylation and methacrylation reactions are often used in UV-curable systems.The amount of 2-hydroxyethyl acrylate or 2-hydroxyethyl methacrylate for the following reaction was computed in relation to the percentage content of -NCO groups.The molar ratio of hydroxyl to isocyanate groups was 1:1. In this step, it was essential to decrease and control the temperature to avoid premature polymerization of unsaturated bonds.The obtained urethane acrylates were transparent, solid and they could be easily powdered, which made it possible to use them as curing agents in UV-curable powder clear coatings.?UV curable resins for incorporation in toner particles are powders based on unsaturated polyesters and poly(urethaneacrylate)s with bis-ethoxylated 2,2-bis-(4-hydroxyphenyl) propane or bis-propoxylated 2,2-bis(4-hydroxyphenyl)propane.The toner particles can be prepared by melt kneading the toner ingredients, i.e., toner resin composition, charge control agent, pigment, etc. After the melt kneading the mixture is cooled and the solidified mass is pulverized-micronized.