| 摘要 |
PURPOSE:To provide an insulating enamel paint containing a resol type p-alkyl phenol/formaldehyde resin and having excellent heat resistance characteristics including heat softening temperature, thermal shock resistance, winding after thermal degradation and dielectric breakdown strength, etc., and high flexibilty. CONSTITUTION:1mol of p-alkylphenol having a substituted 1-8C alkyl group at the p-position (e.g. cresol) is made to react with a formalin soln. prepared by dissolving 1.1-2.5mol of HCHO in a concn. of about 37% in the presence of an about 28% aqueous soln. of 0.02-0.1mol of NH4OH to produce a resol type p-alkyl phenol/formaldehyde resin having a softening point of 40-90 deg.C and a weight-average M.W. of 400-1,500 in terms of PS as measured by GPC. Then 100pts.wt. crosslinking (imidemodified) polyester having a weight-average M.W. of 1,000-100,000, a cross-linked M.W. of 250-700 and an OH value of 150-500 is dissolved in a solvent such as phenol and 1-10pts.wt. alkyl phenol/ formaldehyde resin and additives, etc., are mixed into the soln. |
