| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-viscosity ethylenically unsatd. polyurethane having allophanate groups, a polyisocyanate for preparing the same, and a one- component coating compsn. contg. the same. SOLUTION: This polyurethane substantially has not an isocyanate group and has a content ofβ,γ-ethylenically unsatd. ether groups introduced through allophanate groups of 0.5-10 wt.% (in terms of C=C having a mol.wt. of 24), a content of allophanate groups of 1-20 wt.% (in terms of N2 C2 HO3 having a mol.wt. of 101), and a total content of ethylenically unsatd. groups of 1-15 wt.% (in terms of C=C having a mol.wt. of 24). The ethylenically unsatd. polyisocyanate has allophanate groups, an NCO content of 5-25 wt.%, a content ofβ,γ-unsatd. ethylenically unsatd. groups introduced through allophanate groups of 0.5-15 wt.% (in terms of C=C having a mol.wt. of 24), and an allophnate group content of 1-30 wt.% (in terms of N2 C2 HO3 having a mol.wt. of 101).
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