| 摘要 |
The present invention relates to blocked fluorine-containing polyisocyanates which have a fluorine content, calculated as F=19, of 1.0 to 20.0 wt. %, preferably 4.0 to 10.0 wt. %, and are suitable for preparing stoving coatings having a water- and soil-repellent surface, wherein the fluorine-containing polyisocyanates are based on the reaction product of aliphatic polyisocyanates or polyisocyanate mixtures having an NCO content of 10 to 25 wt. % and a functionality of at least 2.5 with monofunctional isocyanate blocking agents and a fluorinated monoalcohols whereini) 75 to 95 equivalent-% of the isocyanate groups are reacted with isocyanate blocking agents,ii) 5 to 25 equivalent-% of the isocyanate groups are reacted with fluorinated monoalcohols andiii) the equivalents of i) and ii) add up to 100%.The present invention also relates to a process for the preparation of these blocked fluorine-containing polyisocyanates and to their use as crosslinking agents in the preparation of polyurethane plastics, especially polyurethane coatings.
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