| 摘要 |
PURPOSE:To impart a good rust preventing effect to the surface of a zinc coated steel sheet, a tin plate, an Al plated steel sheet, etc. without requiring troublesome pre- and after-treatments by coating the surface with an aq. soln. of gamma-pyrrone derivative. CONSTITUTION:The surface of a metal is coated with an aq. soln. of 3 (or 5)- hydroxy-gamma-pyrrone or its derivative of formula I or II (where X is H, OH, alkyl or carboxyl), e.g. 5-hydroxymethyl-gamma-pyrrone. To the soln. may be added a water sol. polymer such as a maleate copolymer or an acrylate copolymer. The coated metal surface is then dried to form a rust preventing film. The gamma-pyrrone concn. in the soln. is 0.1-10, pref. 0.1- 2%, and in case the polymer is added, it is desirable to be 0.1-5% in respect of economical efficiency and uniformity of the film. |
