Process for producing inorganic fiber-based prepreg sheet and process for producing insulating laminate

Abstract

A process for producing an inorganic fiber-based prepreg sheet, which comprises preparing a slurry containing 35-80% by weight of a phenolic resin powder of 0.01-100 .mu.m in average particle diameter, 65-20% by weight of an inorganic fiber (the amounts are based on the total amount of the two) and a nonionic high-molecular fixing agent, making the slurry into a sheet in the same manner as in the paper making, and allowing the sheet to contain a silane coupling agent; and a process for producing an insulating laminate, which comprises laminating a prepreg sheet produced by the above process. According to the present invention, there can be produced an inorganic fiber-based prepreg sheet which has high insulating, which is superior in heat resistance, moisture resistance, dimensional stability in thickness direction and through hole ability and which gives rise to no whiting even when made into a laminate; and there can also be produced, from a laminate obtained by laminating the above inorganic fiber-based prepreg sheet, a laminate sheet for printed substrates of high-density wiring and mounting.

Dependencies are inferred from the claim text.