Method for painting article to be treated

Abstract

An object of the present invention is to unify sealing treatment and degreasing treatment by treating an anodic oxide film of an article to be treated made from aluminum or an aluminum alloy with a strongly basic treatment liquid containing a lithium ion, and simplify a pretreatment step for painting. A method for painting the article to be treated, by forming the anodic oxide film on the article to be treated made from aluminum or the aluminum alloy, and painting the article to be treated by using the anodic oxide film as a substrate, includes a first step including anodic treatment S 1 and a second step including painting treatment S 3, wherein sealing treatment and degreasing treatment are conducted in a unified way with the use of a strongly basic bath containing the lithium ion.

1 . A method for painting an article to be treated, by forming an anodic oxide film on the article to be treated made from aluminum or an aluminum alloy, and painting the article to be treated by using the anodic oxide film as a substrate, the method comprising:
 a first step including anodizing treatment; and   a second step including painting treatment,   wherein sealing treatment and degreasing treatment are conducted in a unified way with the use of a strongly basic bath containing a lithium ion.   
     
     
         2 . The method for painting the article to be treated according to  claim 1 , wherein a drying step between the first step including the anodizing treatment and the second step including the painting treatment is omitted, and the anodizing treatment, the sealing/degreasing treatment and the painting treatment are conducted as a continuous process. 
     
     
         3 . The method for painting the article to be treated according to  claim 1 , wherein a film thickness of the anodic oxide film formed in the anodizing treatment is 3 μm or more and 40 μm or less. 
     
     
         4 . The method for painting the article to be treated according to  claim 1 , wherein
 a concentration of the lithium ion in the strongly basic bath to be used in the sealing/degreasing treatment is set to 0.02 g/L or more and 20 g/L or less,   a pH value of the strongly basic bath is set to 10.5 or more, and   a treatment temperature is set to 10° C. or higher and 65° C. or lower.   
     
     
         5 . The method for painting the article to be treated according to  claim 1 , wherein lithium hydroxide or lithium carbonate is employed as a source of the lithium ion. 
     
     
         6 . The method for painting the article to be treated according to  claim 3 , wherein in the painting treatment, an immersion method, a spray method or a roll coating method is employed as a painting method, and urethane-based paint, epoxy-based paint or acrylic-based paint is employed.