Patent ID: 11133445

Abstract:
Provided are a metal-base circuit board having excellent solder crack resistance, thermal conductivity, adhesive property, and insulation property and a resin composition for a circuit board used for the metal-base circuit board. A resin composition for a circuit board comprises a vinylsilyl group-containing polysiloxane (having a vinylsilyl group equivalent of 0.005 to 0.045 mol/kg) comprising (A) a dual-end type vinylsilyl group-containing polysiloxane having a weight average molecular weight of 30,000 to 80,000 and (B) a side-chain dual-end type vinylsilyl group-containing polysiloxane having a weight average molecular weight of 100,000 or more, a hydrosilyl group-containing polysiloxane (having a hydrosilyl group equivalent of 6 mol/kg or more), and an inorganic filler at 60 to 80% by volume. The mass ratio of (A) to (B), (A)/(B), is 80/20 to 30/70, and the molar ratio of (C) a hydrosilyl group to (D) a vinylsilyl group, (C)/(D), is 2.5 to 5.0.