| 摘要 |
PURPOSE:To obtain a primer, consisting of an urethane prepolymer having terminal isocyanate groups and polyamine compound and capable of completely sealing pinholes on molded plastic articles by coating therewith. CONSTITUTION:A primer, obtained by dissolving (A) an urethane prepolymer prepared by reacting an excess amount of an isocyanate compound, e.g. trimethylene diisocyanate, with a hydroxyl group-containing compound, e.g. polybutylene adipate, and having free isocyanate groups and (B) a polyamine compound, e.g. ethylenediamine or xylylenediamine, so as to provide 0.2-3, preferably 0.5-2 ratio of isocyanate groups to amino groups, preferably in a solvent, e.g. methyl ethyl ketone, and having 10-60wt.% solid concentration. A molded plastic article is then coated with the resultant primer to produce a molded article without pinholes.
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