| 摘要 |
PURPOSE:To uniformly color the whole surface of copper and obtain various neutral tints by forming a coated film on the surface with a reswellable sizing material contg. sulfiede followed by humidity control and wash-removal of the film. CONSTITUTION:The surface of copper is degreased, pickled to remove impurities, and coated with an aq. soln. of a paste-like reswellable sizing material such as polyvinyl alcohol or carboxymethylcellulose, by screen printing, roll coating or doctor coating, mixed with sulfide such as potassium sulfide, barium sulfide or sodium poly-sulfide or further blended with a filler to form a uniform film on the surface. The coated surface is then huymidity-controlled in an atmosphere of about 80% huymidity at about 20-60 deg.C and washed with water, warm water or an aq. alkali soln. to remove the film. |
