| 摘要 |
Water dilutable polyurethane resin from reaction of polycarbonate polyol, polyesterpolyol, compound with two or more OH and or amino groups, a compound monofunctional in reaction with NCO groups or containing active H atoms of different reactivity, where these structural elements are at the polymer chain ends, a compound having at least two groups reactive to isocyanate groups and at least one group capable of forming anions, and one or more polyisocyanates is new. A water dilutable polyurethane resin obtainable by reaction of :(A1) at least one polycarbonate polyol of molecular weight 400-6000Da, (A2) optionally a polyesterpolyol different from (A1) of number average molecular weight Mn = 400-6000 Da, (A3) optionally a low molecular compound having two or more OH and or amino groups of molecular weight 62-400 Da, (A4) optionally a compound which is monofunctional in relation to reaction with NCO groups or contains active H atoms of different reactivity, where these structural elements are at the chain ends of the urethane group containing polymer, (A5) at least one compound having at lest two groups reactive to isocyanate groups and at least one group capable of forming anions, and (A6) one or more polyisocyanates. Independent claims are also included for the following: (1) a process for preparation of the resin by preparation of an OH- and/or NH-functional polyurethane from components (A1, (A5), and (A6) and optionally component s (A2) to (A4) in a solvent inert to isocyanate groups; (2) an aqueous coating system containing: (a) at least one nonaqueous component containing the water dispersible polyurethane resin, (b) one or more aqueous binder components containing at least one OH group-free polyurethane dispersion, (c) optionally adjuvants and additives, and (d) at least one crosslinker; (3) a process for preparation of the aqueous coating system by working in the water dilutable polyurethane resin in aqueous phase, containing at least one OH group-free aqueous polyurethane dispersion and optionally adjuvants and additives, followed by addition of at least one crosslinker and optionally dispersion of further adjuvants and additives; and (4) a substrate coated with a crosslinked coating system containing the water dilutable polyurethane resin.
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