| 摘要 |
PROBLEM TO BE SOLVED: To decrease moisture absorption of an electrical insulating nonwoven fabric containing an aramid fiber, and to improve moisture resistance and heat resistance of an insulating layer holding a thermosetting resin on the electrical insulating nonwoven fabric. SOLUTION: The electrical insulating nonwoven fabric comprises an aramid fiber nonwoven fabric, wherein surfaces of the aramid fibers are treated with a resol-type phenol resin so as to form phenol resin cured films on the surfaces. The phenol resin cured films are completely cured. A water-soluble low molecular weight phenol resin of resol type in which residual methylol groups are contained in a large amount is preferably used as the resol-type phenol resin. The insulating layer of a laminated sheet or a printed-wiring board is obtained by impregnating the aramid fiber nonwoven fabric with an epoxy resin, and then subjecting the impregnated fabric to hot and press molding. COPYRIGHT: (C)2005,JPO&NCIPI |
