Method for Manufacturing Colored Aluminum Product or Colored Aluminum Alloy Product, Pigment Composition for Coloration, and Colored Aluminum Product or Colored Aluminum Alloy Product

Abstract

A method for manufacturing a colored aluminum product or a colored aluminum alloy product includes the following steps of (i) subjecting a substrate made of aluminum or aluminum alloy to an anodic oxidation in a treatment solution containing phosphoric acid to form an anodic oxidation film having a plurality of pores on a surface of the substrate, (ii) treating the substrate with warm water having a temperature between 40 and 100° C., and (iii) immersing the substrate in a pigment composition for coloration includes pigment particles, a dispersing agent and water to fill the pigment particles into a plurality of the pores in the anodic oxidation film on the surface of the substrate, thereby performing coloration.

1 . A method for manufacturing a colored aluminum product or a colored aluminum alloy product, comprising the following steps of:
 (i) subjecting a substrate made of aluminum or aluminum alloy to an anodic oxidation in a treatment solution containing phosphoric acid to form an anodic oxidation film having a plurality of pores on a surface of the substrate;   (ii) washing the substrate with water, where phosphoric acid ions remain in the plurality of the pores in the anodic oxidation film on a surface of the substrate after washing the substrate;   (iii) drying the substrate with hot air having a temperature between 70° C. and 150° C., thereby removing the phosphoric acid ions remaining in the plurality of the pores in the anodic oxidation film on the surface of the substrate; and   (iv) immersing the substrate dried with the hot air in a pigment composition for coloration comprising pigment particles, a dispersing agent, and water to fill the pigment particles into a plurality of the pores in the anodic oxidation film on the surface of the substrate without using electrophoresis, thereby performing the coloration,   wherein each of the pores in the anodic oxidation film has a pore size between 20 and 200 nm and a depth between 1 and 50 μm in a thickness direction, and   wherein the pigment particles in the pigment composition have a particle size distribution in which a particle size of D 80 is less than the pore size of a minimum pore of the plurality of the pores in the anodic oxidation film in a state in which the pigment particles are dispersed in the pigment composition.   
     
     
         2 . The method of  claim 1 , wherein the dispersing agent is an acrylic resin. 
     
     
         3 . The method of  claim 1 , wherein the dispersing agent is a styrene-acrylic resin. 
     
     
         4 . The method of  claim 1 , wherein the concentration of the pigment particles is from 3% to 30% by weight based on the total amount of the pigment composition, and the concentration of the dispersing agent is from 1% to 10% by weight based on the total amount of the pigment composition. 
     
     
         5 . The method of  claim 1 , wherein the pigment composition has an oxidation-reduction potential of 200 mV or less. 
     
     
         6 . The method of  claim 5 , wherein the oxidation-reduction potential is 150 mV or less.