| 摘要 |
PURPOSE:To provide an electrical insulating varnish which is excellent in both cold curing and electrical insulating properties and has a service life sufficient for practical use, by incorporating a specific polybutadiene derivative, an alpha,beta-unsaturated monomer, a specific peroxide and a metal salt of a carboxylic acid. CONSTITUTION:An electrical insulating varnish comprising a polybutadiene derivative (A) prepared by reacting a copolymer comprising a butadiene having a number-average molecular weight of 500-20,000 and a functional group having an active hydrogen in its molecule and which is solid at room temp. and melts at 40 deg.C higher and styrene and/or alpha-methylstyrene with an isocyanate group having a polymerizable unsaturated group in its molecule in an amount of 0.5-2 equivalents of the isocyanate group per equivalent of the active hydrogen, an alpha,beta-unsaturated monomer (B), a hydroperoxide and/or a peroxy ester (C) and a metal salt of an organic carboxylic acid (D). The varnish may optionally be incorporated with a polymerization inhibitor, a plasticizer, a thermoplastic resin, a filler, a flame retardant, etc.
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