| 摘要 |
A moisture-proof insulating coating for resistors, condensers, inductances or other electrical components comprises a base coat of monochlorotrifluoroethylene and a cover coat of silicone varnish, both being polymerized after their application, the varnish comprising a non-ionic higher alcohol wetting agent to ensure that the cover coat adheres uniformly to the polymerized base coat. The base coat solution may consist of 25 per cent. water-ground mica filler and 75 per cent. of a 56 per cent. suspension of monochlorotrifluoroethylene in xylol. After dipping the component in this solution it is dried and baked at 400 DEG F. to 450 DEG F. The silicone varnish, which is then added to provide a moisture barrier may consist of 75 per cent. of Dow Corning 996 polymethylsiloxane varnish (65 per cent. solids in xylol) 24 per cent. of water-ground mica filler, and 1 per cent. of alkyl aryl polyether alcohol as a wetting agent. The particular silicone varnish, higher alcohol or filler specified is not critical. The exterior coating is cured in a circulating air oven at 300 DEG F. Two or more separate coatings may be applied. |
