SURFACE TREATMENT OF POLYACETAL ARTICLES

摘要

Polyacetal articles are etched to prepare the surface for subsequent treatments, in particular plating and painting, by immersing the articles in a mixed acid bath containing the following four acids and water in the following quantities and proportions: 28 to 39 weight% of sulfuric acid and 25 to 32 weight% of phosphoric acid, wherein the ratio by weight of sulfuric acid to phosphoric acid is in the range from 0.9 to 1.5; 3 to 10 weight% hydrochloric acid and 3 to 14 weight% acetic acid, wherein the ratio by weight of hydrochloric acid to acetic acid is in the range 0.25 to 3.0; and5 to 41 weight% water;at a temperature in the range 25 - 35 DEG C for a duration of up to 60 minutes. This etching process has a wider processing window than prior art processes.