MANUFACTURE OF FLY-BACK TRANSFORMER

摘要

PURPOSE:To improve a withstand voltage characteristic, by using an acid anhydride to harden coast resin composition which is formed by blending two epoxy compounds of specific composition in a specific ratio. CONSTITUTION:An acid anhydride is used to harden a cast resin composition which is formed by using base resin to blend two epoxy compounds shown in formulas I and II in a ratio of 70-90 pts. wt. and 10-30 pts. wt., respectively. The epoxy compound shown in the formula I is liquid epoxy resin of a bisphenol type obtained by reaction of bivalent phenol with epichlorohydrin. The epoxy compound shown in the formula II is ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, or the like. A methyl tetrahydra acid anhydride is desirable as the acid anhydride hardening agent. When the epoxy compounds are blended in said ratio, a withstand voltage characteristic of urethane coated copper wire can be improved and long life of FBT can be realized.