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.

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.

Abstract: A method of manufacturing a metal-base substrate having an insulative adhesive layer and a conductor layer on a metal-based material is provided. The method includes the steps of dispersing a disperse phase in an insulative adhesive-dispersing medium that contains a wetting dispersant and constitutes the insulative adhesive layer; laminating step of laminating the insulative adhesive on the conductor foil as feeding the roll-shaped conductor foil; curing the insulative adhesive on the conductor foil under heat into a B stage state and thus forming a composite of the conductor foil and the insulative adhesive layer in the B stage state; laminating the metal-based material on the insulative adhesive layer in the B stage state to give a laminate; and then curing the insulative adhesive layer in the B stage state into a C stage state by heat pressurization of the laminate.

Abstract: A method of manufacturing a metal-base substrate having an insulative adhesive layer and a conductor layer on a metal-based material is provided. The method includes the steps of dispersing a disperse phase in an insulative adhesive-dispersing medium that contains a wetting dispersant and constitutes the insulative adhesive layer; laminating step of laminating the insulative adhesive on the conductor foil as feeding the roll-shaped conductor foil; curing the insulative adhesive on the conductor foil under heat into a B stage state and thus forming a composite of the conductor foil and the insulative adhesive layer in the B stage state; laminating the metal-based material on the insulative adhesive layer in the B stage state to give a laminate; and then curing the insulative adhesive layer in the B stage state into a C stage state by heat pressurization of the laminate.

Abstract: To provide a thin metal base circuit board which can be not only installed on a flat portion but also closely attached to a side or bottom surface of a case or to a stepped or curved portion and which is excellent in heat dissipation performance, electrical insulating performance and flexibility; a process for its production; and a hybrid integrated circuit, an LED module and a bright, ultra-long-life LED light source employing it. A metal base circuit board having insulating layers and conductive circuits or metal foils alternately laminated, characterized in that the thickness of each conductive circuit or metal foil is from 5 ?m to 450 ?m, each insulating layer is made of a cured product of a resin composition comprising an inorganic filler and a thermosetting resin, and the thickness of each insulating layer is from 9 ?m to 300 ?m; and a hybrid circuit board employing it.

Abstract: A metal base circuit board to be used for a hybrid integrated circuit, including circuits provided on a metal plate via an insulating layer, a power semiconductor mounted on the circuit, and a control semiconductor to control the power semiconductor, provided on the circuit. A low capacitance portion is embedded under a circuit portion on which the control semiconductor is mounted, preferably. The low capacitance portion is made of a resin containing an inorganic filler and has a dielectric constant of from 2 to 9.

Abstract: To provide an LED light source unit which is excellent in heat dissipation performance, able to prevent damage to LED and bright, and which has a long life. An LED light source unit comprising a printed board, at least one light emitting diode provided on the printed board, and an adhesive tape for fixing the printed board on the surface of a heat dissipating member, wherein the thermal conductivity of the adhesive tape is from 1 to 4 W/mK, and the withstand voltage between a rear side conductor circuit and a metal housing is at least 1.0 kV.

Abstract: To provide an LED light source unit which is excellent in heat dissipation performance, able to prevent damage to LED and bright, and which has a long life. An LED light source unit comprising a printed board, at least one light emitting diode provided on the printed board, and an adhesive tape for fixing the printed board on the surface of a heat dissipating member, wherein the thermal conductivity of the adhesive tape is from 1 to 4 W/mK, and the withstand voltage between the fixing face of the printed board and the fixing face of the heat dissipating member is at least 1.0 kV.

Abstract: To provide a thin metal base circuit board which can be not only installed on a flat portion but also closely attached to a side or bottom surface of a case or to a stepped or curved portion and which is excellent in heat dissipation performance, electrical insulating performance and flexibility; a process for its production; and a hybrid integrated circuit, an LED module and a bright, ultra-long-life LED light source employing it. A metal base circuit board having insulating layers and conductive circuits or metal foils alternately laminated, characterized in that the thickness of each conductive circuit or metal foil is from 5 ?m to 450 ?m, each insulating layer is made of a cured product of a resin composition comprising an inorganic filler and a thermosetting resin, and the thickness of each insulating layer is from 9 ?m to 300 ?m; and a hybrid circuit board employing it.