| 摘要 |
1399418 Pre-paint coating constituent DIAMOND SHAMROCK CORP 17 Oct 1973 [18 Oct 1972] 48402/73 Heading C4A A pre-cursor constituent for preparing a prepaint coating composition comprises an aqueous medium, chromic acid, a reducing agent for the hexavalent chromium provided by the chromic acid and a compatible pH adjustment agent, the chromic acid plus reducing agent being present in an amount so as to provide a pH in water of below 0À8, and the pH adjuster being present in such an amount to give a pH of 0À8 to 6À0 for the precursor constituent. The pH adjuster may be an oxide or hydroxide of metal other than Na, K, Rb or Cs which is soluble in the aqueous chromic acid. The reducing agent is preferably a dicarboxylic acid containing succinimide, acrylamide or aspartic acid. Tertiary alcohols and/or chlorinated hydrocarbons may be added to the aqueous medium. The precurosr constituent is added to a constituent including pulverulent Zn to prepare an anticorrosive pre-paint coating composition. |
