ALUMINUM SHEET TO BE MOLDED INTO CAP HAVING SUPERIOR ADHESIVENESS TO RESIN AND CORROSION RESISTANCE AFTER HAVING BEEN MOLDED, AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide an aluminum sheet to be molded into a cap, in which a paint film containing a large amount of pigment shows superior molding workability even when the paint film is subjected to an extremely severe molding operation, and shows high adhesiveness and corrosion resistance. SOLUTION: This aluminum sheet to be molded into the cap is manufactured by the steps of: subjecting the surface of an aluminum sheet to alkaline degreasing treatment; cleaning the degreased sheet by spraying and jetting a cleaning liquid of 20 to 80°C to the degreased sheet at a rate of 3 to 50 liter/m2per second with a jetting pressure of 1.0 to 3.5 kgf/cm2; and forming a paint film containing a pigment of 5 mass% or more with respect to a dry weight of the paint film. Thus manufactured aluminum sheet has a chemical conversion coating in which the content of aluminum hydrous oxide is 100 mg/m2or less. The cleaning liquid preferably contains a complex-forming substance having such a stability constant (KA) with an aluminum ion (Al3+) as to satisfy logKA≥15 in an amount of 0.05 to 0.5 mol/liter. COPYRIGHT: (C)2008,JPO&INPIT