| 摘要 |
PROBLEM TO BE SOLVED: To inexpensively produce a precoated steel panel good in processability and pressure mark resistance without requiring an excessive process. SOLUTION: Topcoat paint containing copolyester with a number average mol.wt. of 8000-25,000 and an alkyl etherified aminoformaldehyde resin (AEAFA resin) in a wt. ratio of 90/10-70/30 is applied to a steel panel and the formed coating film is baked by hot air drying controlled so that the wind velocity on the surface of the steel panel becomes 0.5-3.0m/sec to form the uppermost resin layer of a precoated steel panel. This resin layer has the AEATA resin conc. on the surface thereof so that the concn. of the surface AEAFA resin calculated by formula [wherein N1 is the N-concn. (at%) of the uppermost layer measured by an X-ray photoelectronic spectral method of the resin layer and N0 is the N-concn. (at%) of the uppermost layer of a resin layer composed only of the AEAFA resin] becomes 30-80%. |
