| 摘要 |
<p>Preparing (P1) a low-viscosity, water-dilutable polyurethane (meth)acrylate involves reacting (a) organic polyisocyanate with two isocyanate functions, (b) polyoxyalkylene polyol based on a starter molecule which contains hydroxy functions and is partially reacted by esterification with (meth)acrylic acid, and (d) compound which has at least one group which is reactive towards isocyanate and ionic or potentially ionic function, to form the (meth)acrylate, where the (meth)acrylate is not prepared from organic polyisocyanates with isocyanate functions, and polyoxyalkylene polyols. Preparing (P1) a low-viscosity, water-dilutable polyurethane (meth)acrylate involves reacting (a) at least one organic polyisocyanate with two isocyanate functions, (b) at least one polyoxyalkylene polyol based on a starter molecule which contains at least three hydroxy functions and is partially reacted by esterification with (meth)acrylic acid such that on average 0.2 to 1.5 hydroxy functions still remain, and (d) at least one compound which has at least one group which is reactive towards isocyanate and at least one ionic or potentially ionic function, to form the low-viscosity, water-dilutable polyurethane (meth)acrylate, where the reaction product of components (a), (b), and (d) has an isocyanato content of less than 0.5 wt.%, and the polyurethane (meth)acrylate is not prepared from components selected from (i) organic polyisocyanates with at least three isocyanate functions, and polyoxyalkylene polyols which have a maximum of two hydroxy functions but no further groups which can be crosslinked by actinic radiation. Independent claims are included for the following: (1) a water-dilutable polyurethane (meth)acrylate obtained by the process (P1); (2) a coating comprising the water-dilutable polyurethane (meth)acrylate; (3) a coating composition (C1) comprising either the urethane (meth)acrylate, compounds which differ from urethane (meth)acrylate and contain groups which react, by polymerization, with ethylenically unsaturated compounds under the action of actinic radiation, aqueous binders which are not radiation-curable, initiators, optionally water and/or solvents, and optionally auxiliary substances and additives; or at least one urethane (meth)acrylate, compounds, dissolved or dispersed in water, which contain unsaturated radiation-curable groups, compounds, dissolved or dispersed in water, which contain no unsaturated radiation-curable groups, initiators, optionally water and/or solvents, and F) optionally auxiliary substances and additives; and (4) a substrate coated with the composition (C1).</p> |
