Patent ID: 8063144

Claim:
A process for preparing a liquid polyacrylate-modified polyisocyanate of the formula (I): wherein R is hydrogen or a methyl group, R 1 is an optionally heteroatom-containing hydrocarbon radical, R 2 is a hydrocarbon radical having at least one isocyanate group and optionally a urethane, allophanate, biuret, uretdione, isocyanurate or iminooxadiazinedione group, and n is a number ≧1; the process comprising: (a) providing a starting polyisocyanate selected from the group consisting of aromatic, araliphatic, cycloaliphatic, and aliphatic polyisocyanates and mixtures thereof having an NCO content of 5% to 25% by weight, an NCO functionality ≧2 and a viscosity measured as solvent free resin of 150 to 200,000 mPa·s at 23° C.; (b) reacting a portion of the isocyanate groups of the starting polyisocyanate with a monoalcohol containing acrylate and/or methacrylate groups to form urethane groups, such that not more than 40 mole % of the isocyanate groups in the starting polyisocyanate are converted to urethane groups; and (c) subsequently to or simultaneously with the urethanization, reacting the unsaturated groups of the resulting reaction product by free-radically initiated polymerization optionally with other additional unsaturated monomers, to form the liquid polyacrylate-modified polyisocyanate of the formula (I).