Printing screen of metallic or metallised filaments - blocked off according to a pattern by electrolytic deposition of metal

摘要

The screen is blocked off according to a required pattern in certain areas by electrolytic deposition of metal. An accurate pattern can be formed and the screen is resistant to wear. In an example, the screen is made from stainless steel wires and is coated with copper in a copper pyrophosphate bath. The copper layer is then coated with a photosensitive resin which is exposed through a pattern mask and then developed to remove resin in the exposed areas. The reverse face of the screen is then coated with a protective varnish and the exposed areas of the copper layer chemically etched away using e.g. a mixt. of sodium chlorite, ammonium citrate, ammonia. Finally the varnish and remaining resin are removed by a solvent e.g. methylene chloride, dimethyl formamide.