To provide a thermosetting resin composition for a printed wiring board, the composition used as the inner layer adhesive of a multilayer printed wiring board for usage in a high-frequency range, and satisfying a low coefficient of thermal expansion, a low dielectric constant, low dielectric loss, low moisture absorption and good hyper-multilayer formability, and to provide a resin varnish, a prepreg and a metal-clad laminate using the composition.
The thermosetting resin composition contains an uncured semi-IPN composite material and (D) a radical reaction initiator. The uncured semi-IPN composite material comprises (A) a polyphenylene ether compatibilized with a prepolymer formed of (B) a chemically unmodified butadiene polymer containing 1,2-butadiene units having 1,2-vinyl groups in side chains by 40% or more in the molecule and (C) a crosslinking agent. The component (D) comprises a dialkyl peroxide-based radical reaction initiator and a hydroperoxide-based radical reaction initiator. There are provided the resin varnish, the prepreg and the metal-clad laminate using the thermosetting resin composition.
MIZUNO YASUYUKI
KAMIYAMA KENICHI
