Abstract: One or more parts having terminals can be mounted on a circuit board by coating an ultraviolet-curing and thermosetting resin composition comprising an ultraviolet-curing resin, an addition polymerizable monomer, a photosensitizer and a heat polymerization initiator, on the circuit board by screen printing with a prescribed pattern, mounting the parts on the printed resin composition, curing the resin composition by simultaneous irradiation of ultraviolet light and heat rays so as to bond the parts to the circuit board, and soldering the parts onto the circuit board.

Abstract: Flame-retardant epoxy resin compositions comprising a polyepoxide, an acid anhydride curing agent, an imidazole curing accelerator, aluminum trihydrate powder and red phosphorus powder or red phosphorus powder coated by a thermo-setting resin have a lower viscosity and therefore show a longer pot life and better workability on casting as compared with prior art resin compositions. Also, a fly-back transformer coil produced by casting of said flame-retardant epoxy resin compositions is flame-retardant. Even if it burns slightly, no toxic gas is produced. Therefore, the coil has advantages in that a magnet wire is not corroded and voids are difficult to be formed and thereby partial discharge is difficult to occur, resulting in a long life and a stable output voltage.