GB552152A - Improvements relating to coating compositions suitable for providing electric wires with insulating coverings and for other purposes - Google Patents

Abstract

552,152. Resinous compositions for coating wires. BRITISH INSULATED CABLES, Ltd., and COWEN, J. F. July 23, 1941, No. 9290. [Class 2 (iii)] Compositions for coating wires and other metal articles to give insulation and corrosion and abrasion resistance consist of a mixture of 98-55 per cent. polyvinyl acetal resin, e.g. a polyvinyl formal, 2-45 per cent. melaminealdehyde resin, e.g. a melamine-formaldehyde resin (based on the weight of total resin content), pine oil and one or more solvents (not of low boiling point). A preferred mixture contains 14 parts of polyvinyl acetal resin, 6 parts of melamine resin, pine oil and one or more of the solvents. The composition may consist of 20 per cent. of resins and 75 per cent. solvents and may be prepared by mixing the resins and pine oil and refluxing with 20 per cent. of the solvent until clear, when the remainder of the solvent is added. A coating may be obtained by passing an article one or more times through a bath of the composition and baking the article after each passage through the bath. The bath may be slightly above atmospheric temperature and the baking temperature 350- 430 ‹C. In the example 14 parts polyvinyl acetal resin, 6 melamine resin, 5 pine oil, 20 ethyl lactate, 40 xylol and 15 coal tar naphtha are used.