PURPOSE: To obtain a prepreg excellent in dielectric characteristics and used for the production of a laminate by selecting specified heat drying conditions in a process for producing a prepreg by impregnating a base with a polyphenylene ether resin varnish and drying the varnish.
CONSTITUTION: A process for producing a prepreg comprising impregnating a base with a varnish comprising a polyphenylene ether resin, a cross-linkable resin (e.g. 1,2-polybutadiene, 1,4-polybutadiene or styrene/butadiene copolymer), a cross-linking aid (e.g. ester acrylate, epoxyacrylate, triallyl cyanurate or divinylbenzene), an initiator, an inorganic filler and a halogen-free solvent, wherein the heat drying conditions are represented by the region surrounded by the square having the four vertices A (80, 1.5), B (80, 5.5), C (140, 4.5) and D (140, 0.5) and shown by the graph of the figure (wherein X-axis represents the temperature (°C), and Y-axis represents the heat drying time (min)).
YAMAKAWA SEISHIRO
KOSEKI TAKAYOSHI
HIRATA ISAO
