| 摘要 |
Formed articles of high-molecular weight thermoplastic polycarbonates are treated, optionally at an elevated temperature, with aqueous or alcoholic solutions of alkali or alkaline-earth metal hydroxides. The articles, which may be foils, fibres, bristles or domestic articles, are thereby given a uniform roughened, matt surface which is suitable for marking with dyes, inks, pencils and the like. The surfaces so treated also have improved adhesive properties for coatings of various materials. The process can be applied to articles which have been dyed, and, by the use of suitable masking techniques, pre-selected portions of the surface may be treated. The process does not impair the chemical, mechanical or electrical properties of the formed articles. In the examples, articles made from a melt of bis-(p-hydroxyphenyl)-dimethyl-methane polycarbonate are dipped in a 50% aqueous solution of sodium hydroxide at 80 DEG -130 DEG for 1-8 minutes. The articles so treated are washed free from alkali with water and acetic acid. |
