| 摘要 |
Radiation-curable, polyurethane acrylate-based aqueous dispersion comprises (a) one or more compounds having at least one group reactive against isocyanate and at least one radically polymerizable unsaturated group, (b) one or more compounds that are different from (a) having at least one group reactive against isocyanate, (c) one or more compounds having a group reactive against isocyanate and additionally at least one hydrophilic group, and (d) one or more organic polyisocyanate that reacts in the presence of bismuth(III) salts and an acid having a negative logarithm of acid dissociation constant (pKa) value of less than 2.5. Independent claims are included for: (1) preparing the aqueous dispersion comprising reacting the components (a) to (c) in one or more reaction steps with component (d) in the presence of bismuth(III) salts and acid to obtain polyurethane acrylate, where a neutralization agent for producing the ionic group for the dispersion is added before, during or after the preparation of addition product of (a)-(d), followed by a dispersion step by the addition of water to the addition product of (a)-(d) and/or transporting the addition product of (a)-(d) into an aqueous solution in which a chain elongation is carried out, before, during or after dispersing step, using a component (e) having at least one group reactive against isocyanate, where the component (e) is different from the components (a)-(d); (2) a coating agent comprising the above aqueous dispersion, crosslinker based on amino resin, blocked or non-blocked polyisocyanate, hydrophilized polyisocyanate, polyaziridine and/or polycarbodiimide, and/or one or more further dispersions; and (3) a substrate coated with the coating agent. |
