| 摘要 |
PROBLEM TO BE SOLVED: To provide aqueous radiation-curable polyurethane compositions that provide pigmented coatings showing high end hardness and scratch resistance.SOLUTION: The aqueous radiation-curable composition comprises at least one high molecular weight ethylenically unsaturated polyurethane (A) and a low molecular weight ethylenically unsaturated polyurethane (B) different from polyurethane (A). The ethylenically unsaturated polyurethane (A) is obtained from the reaction of: at least one polyisocyanate compound; at least one ethylenically unsaturated compound containing at least two reactive groups capable to react with isocyanate groups; at least one hydrophilic compound containing at least one reactive group capable to react with isocyanate groups and capable to render the polyurethane prepolymer dispersible in aqueous medium either directly or after the reaction with a neutralizing agent to provide a salt; at least one active hydrogen-containing chain extender capable to react with isocyanate groups and provide chain extension; and, optionally one or more polyol. |
