Elektrisches Bauelement aus Metall

摘要

Metal articles, e.g. steel panels, are coated with a composition comprising (1) 25 to 94% of an epoxy resin comprising the reaction product of a polyhydric phenol and an epihalohydrin (2) 1 to 25% of a polyvinyl acetal resin and (3) 5 to 70% of a polymer or copolymer of esters of acrylic or methacrylic acids. The epoxy resin may be derived from hydroquinone, resorcinol, bis-(4-hydroxyphenol)-2,2-propane or poly (hydroxyphenyl) pentadecanes and epichlorohydrin. The polyvinyl acetal may be the formal, acetal or butyral and component (3) may be derived from the methyl, ethyl, butyl or isobutyl esters of acrylic or methacrylic acid. The composition may also contain colloidal silica or a pigment and a catalyst for curing the epoxy resin, e.g. dicyandiamide, acid anhydrides, boron trifluoride or various amines. The metal articles may be components of electrical equipment such as transformers, cutouts, capacitors and switchgear and may be coated with the above composition by the fluidized bed method or by spraying or brushing methods, the composition then being dissolved in a suitable solvent such as acetone-ethylene dichloride, followed by curing at, e.g. 200 DEG C. Specifications 518,057 and 579,698 are referred to.ALSO:A coating composition comprises (1) 25 to 94% of an epoxy resin comprising the reaction product of a polyhydric phenol and an epihalohydrin, (2) 1 to 25% of a polyvinyl acetal resin and (3) 5 to 70% of a polymer or copolymer of esters of acrylic or methacrylic acids. The epoxy resin may be prepared by reacting hydroquinone, resorcinol, bis-(4-hydroxyphenyl)-2,2-propane or poly(hydroxyphenyl) pentadecanes with epichlorohydrin. The polyvinyl acetal may be the formal, acetal or butyral and component (3) may be derived from the methyl, ethyl, butyl or isobutyl esters of acrylic or methacrylic acid. The coating composition may also contain colloidal silica, or a pigment, and a catalyst such as dicyandiamide, maleic, chlorendic or pyromellitic anhydride, methylene dianiline, ethylene diamine, diethylene triamine, piperidine or boron trifluoride for curing the epoxy resin. The composition may be used to coat metal articles by the fluidized bed method, or by spraying or brushing methods, using a solution of the composition in a suitable solvent such as an acetone-ethylene dichloride mixture. Specifications 518,057 and 579,698 are referred to.