| 摘要 |
PURPOSE:To obtain a coating material for a metal plate which can provide a corrosion-proof coated metal plate in which the processed part is hardly cracked even at high humidity and high temperature by dissolving a polyester resin and a block isocyanate in an organic solvent and adjusting the softening point of the resin, the boiling point of the solvent and the temperature at which a reaction starts. CONSTITUTION:A coating material consisting of a composition obtained by dissolving a polyester resin with a glass transition temperature of 40 deg.C or above and a block isocyanate as a cross-linking agent in an organic solvent, in which the softening point (Tm) of the polyester resin, the boiling point (Tv) of the organic solvent and the temperature at which a reaction of a block isocyanate starts (Tr) satisfy the relationships of Tm<Tr and Tv<=Tr+50. The coating material is applied to the surface of a metal plate, and the resulting coating film is dried at a temperature above Tv but below Tr+50 deg.C, whereby a thermoplastic dry coating film is formed on the metal plate. |
