| 摘要 |
PROBLEM TO BE SOLVED: To provide a printed wiring board, which can be made lightweight and small in dielectric constant and has not only superior heat resistance and electric insulation by moisture absorption, but also superior process passableness end resin impregnability of a resin impregnating process. SOLUTION: The sheet for a printed wiring board is wet type nonwoven fabric obtained by mixing polyphenylene sulfide fiber and undrawn polyphenylene sulfide fiber in 90:10 to 10:90 weight proportion and the air permeability measured on the basis of JIS L-1096 (6.27.1-A law) is >=3 cc/cm2/sec. This sheet is manufactured by mixing the polyphenylene sulfide fiber and undrawn polyphenylene sulfide fiber within the range of the mentioned weight ratio, and then carrying out wet sheet-making and heat pressing. |
