Abstract: A resin composition contains a thermosetting resin (A) and an inorganic filler (B). The inorganic filler (B) includes: a first filler (B1); and a second filler (B2) of a nanometer scale having a smaller particle size than the first filler (B1). The first filler (B1) includes an anhydrous magnesium carbonate filler (b1) and an alumina filler (b2). The proportion of the first filler (B1) relative to a total solid content in the resin composition is equal to or greater than 50% by volume and equal to or less than 90% by volume. The proportion of the second filler (B2) relative to the total solid content in the resin composition is equal to or greater than 0.1% by volume and equal to or less than 2.0% by volume.

Abstract: A resin sheet according to the present disclosure includes an uncured product or semi-cured product of a thermosetting resin composition. A melt viscosity of the resin sheet is equal to or greater than 10 Pa·s and equal to or less than 2000 Pa·s when measured using a Koka flow tester under a measuring condition including 130° C. and 1 MPa and is equal to or greater than 6 Pa·s and equal to or less than 1200 Pa·s when measured using the Koka flow tester under a measuring condition including 130° C. and 4 MPa.

Abstract: The present disclosure provides a thermosetting resin sheet that makes it easier, while an insulating layer where a conductor is to be embedded is being formed, to embed the conductor in the insulating layer and reduces the chances of causing a decline in moldability. A thermosetting resin sheet (1) includes a prepreg layer (2) and a resin sheet layer (3) stacked on the prepreg layer (2). The prepreg layer (2) includes a base member (4) and an uncured product or semi-cured product of a first thermosetting resin composition impregnated into the base member (4). The resin sheet layer (3) is an uncured product or semi-cured product of a second thermosetting resin composition. A curing time of the resin sheet layer (3) is longer than a curing time of the prepreg layer (2).

Abstract: A resin composition contains a resin component (A) and a phosphorus-containing flame retardant (B). The resin component (A) contains an epoxy resin (a1), of which the viscosity at 25° C. is equal to or less than 50000 mPa·s. The proportion of the epoxy resin (a1) to the resin component (A) is equal to or greater than 20% by mass. The phosphorus-containing flame retardant (B) includes a phosphorus-containing flame retardant (B1) that neither melts nor thermally decomposes at a temperature lower than 150° C.

Abstract: A resin composition includes: a resin as Component (A); and an inorganic filler as Component (B). The Component (B) includes anhydrous magnesium carbonate as Component (b1) and aluminum oxide as Component (b2). Content of the Component (b1) falls within a range from 35% by volume to 65% by volume relative to 100% by volume of the Components (b1) and (b2) combined. Content of the Component (B) falls within a range from 60% by volume to 75% by volume relative to 100% by volume of the resin composition.

Abstract: A resin composition contains a thermosetting resin (A) and an inorganic filler (B). The inorganic filler (B) includes: a first filler (B1); and a second filler (B2) of a nanometer scale having a smaller particle size than the first filler (B1). The first filler (B1) includes an anhydrous magnesium carbonate filler (b1) and an alumina filler (b2). The proportion of the first filler (B1) relative to a total solid content in the resin composition is equal to or greater than 50% by volume and equal to or less than 90% by volume. The proportion of the second filler (B2) relative to the total solid content in the resin composition is equal to or greater than 0.1% by volume and equal to or less than 2.0% by volume.

Abstract: The thermosetting resin composition contains a radical polymerizable unsaturated compound and an organic radical compound.

Abstract: A printed wiring board includes: an inner insulating layer including a conductive wire; a first outermost insulating layer disposed on a first surface of the inner insulating layer; and a second outermost insulating layer disposed on a second surface of the inner insulating layer. A bending elastic modulus of each of the first outermost insulating layer and the second outermost insulating layer ranges from ¼ to ¾, inclusive, of a bending elastic modulus of the inner insulating layer. A glass transition temperature of each of the first outermost insulating layer and the second outermost insulating layer falls within ±20° C. of a glass transition temperature of the inner insulating layer.

Abstract: A resin composition includes: a resin as Component (A); and an inorganic filler as Component (B). The Component (B) includes anhydrous magnesium carbonate as Component (b1) and aluminum oxide as Component (b2). Content of the Component (b1) falls within a range from 35% by volume to 65% by volume relative to 100% by volume of the Components (b1) and (b2) combined. Content of the Component (B) falls within a range from 60% by volume to 75% by volume relative to 100% by volume of the resin composition.

Abstract: A thick conductor built-in type printed wiring board includes a printed wiring board, an insulating resin layer, an insulating base material layer, and a conductor layer. The printed wiring board includes an insulating layer including a cured product of a first resin composition, and a circuit provided on one main surface or both main surfaces of the insulating layer, the circuit having a plurality of conductor wirings each having a thickness ranging from 105 ?m to 630 ?m, inclusive. The insulating resin layer covers a surface of the printed wiring board on which the circuit is provided, and includes a cured product of a second resin composition and includes no fibrous base material. The insulating base material layer covers the insulating resin layer, and includes a cured product of a third resin composition and a fibrous base material. The conductor layer covers the insulating base material layer.

Abstract: A thick conductor built-in type printed wiring board includes a printed wiring board, an insulating resin layer, an insulating base material layer, and a conductor layer. The printed wiring board includes an insulating layer including a cured product of a first resin composition, and a circuit provided on one main surface or both main surfaces of the insulating layer, the circuit having a plurality of conductor wirings each having a thickness ranging from 105 ?m to 630 ?m, inclusive. The insulating resin layer covers a surface of the printed wiring board on which the circuit is provided, and includes a cured product of a second resin composition and includes no fibrous base material. The insulating base material layer covers the insulating resin layer, and includes a cured product of a third resin composition and a fibrous base material. The conductor layer covers the insulating base material layer.

Abstract: A printed wiring board includes: an inner insulating layer including a conductive wire; a first outermost insulating layer disposed on a first surface of the inner insulating layer; and a second outermost insulating layer disposed on a second surface of the inner insulating layer. A bending elastic modulus of each of the first outermost insulating layer and the second outermost insulating layer ranges from 1/4 to 3/4, inclusive, of a bending elastic modulus of the inner insulating layer. A glass transition temperature of each of the first outermost insulating layer and the second outermost insulating layer falls within ±20° C. of a glass transition temperature of the inner insulating layer.

Abstract: A (meth)acrylate resin composition of the present invention contains: a (meth)acrylic resin composition (A) containing a (meth)acrylic acid ester and a poly(meth)acrylic acid ester; and a crosslinking agent (B) containing a bifunctional (meth)acrylic monomer (C) represented by chemical formula 1 and a polyfunctional unsaturated ester compound (D) containing three or more radically polymerizable functional groups. The bifunctional (meth)acrylic monomer (C) is contained in an amount of 2 to 25 parts by mass and the polyfunctional unsaturated ester compound containing three or more radically polymerizable functional groups is contained in an amount of 0.1 to 5 parts by mass, based on 100 parts by mass of the (meth)acrylic resin composition (A).

Abstract: An object of the invention is to provide a poly(phenylene ether) resin composition that allows production of laminated sheets excellent in heat resistance and processability, even in case of using a low molecular weight PPE for convenience in prepreg manufacturing without the sacrifice of dielectric characteristics. The poly(phenylene ether) resin composition according to the present invention comprises poly(phenylene ether) and a crosslinking curing agent, wherein the poly(phenylene ether) is represented by the following formula (I) and the number averaged molecular weight thereof is in the range of 1,000 to 7,000. [wherein, X is an aryl group; (Y)m is a poly(phenylene ether) moiety; Z is a phenylene group and the like; R1 to R3 each independently is a hydrogen atom, and the like; n is an integer of 1 to 6; and q is an integer of 1 to 4.

Abstract: An object of the invention is to provide a poly(phenylene ether) resin composition that allows production of laminated sheets excellent in heat resistance and processability, even in case of using a low molecular weight PPE for convenience in prepreg manufacturing without the sacrifice of dielectric characteristics. The poly(phenylene ether) resin composition according to the present invention comprises poly(phenylene ether) and a crosslinking curing agent, wherein the poly(phenylene ether) is represented by the following formula (I) and the number averaged molecular weight thereof is in the range of 1,000 to 7,000. [wherein, X is an aryl group; (Y)m is a poly(phenylene ether) moiety; Z is a phenylene group and the like; R1 to R3 each independently is a hydrogen atom, and the like; n is an integer of 1 to 6; and q is an integer of 1 to 4.

Abstract: An object of the invention is to provide a poly(phenylene ether) resin composition that allows production of laminated sheets excellent in heat resistance and processability, even in case of using a low molecular weight PPE for convenience in prepreg manufacturing without the sacrifice of dielectric characteristics. The poly(phenylene ether) resin composition according to the present invention comprises poly(phenylene ether) and a crosslinking curing agent, wherein the poly(phenylene ether) is represented by the following formula (I) and the number averaged molecular weight thereof is in the range of 1,000 to 7,000. [wherein, X is an aryl group; (Y)m is a poly(phenylene ether) moiety; Z is a phenylene group and the like; R1 to R3 each independently is a hydrogen atom, and the like; n is an integer of 1 to 6; and q is an integer of 1 to 4.

Abstract: An object of the invention is to provide a poly(phenylene ether) resin composition that allows production of laminated sheets excellent in heat resistance and processability, even in case of using a low molecular weight PPE for convenience in prepreg manufacturing without the sacrifice of dielectric characteristics.

Abstract: An epoxy resin composition of the invention comprises: an epoxy resin; a hardening agent; and a phenol-modified polyphenylene oxide having a number average molecular weight of 1000 to 4000, which is prepared by carried out a redistribution reaction between a polyphenylene oxide and a phenol compound in the presence of a reaction initiator which can be decomposed to generate an alcohol, a prepreg and a metal-clad laminate of the invention contain the epoxy resin composition.

Abstract: An epoxy resin composition of the invention comprises: an epoxy resin; a hardening agent; and a phenol-modified polyphenylene oxide having a number average molecular weight of 1000 to 4000, which is prepared by carried out a redistribution reaction between a polyphenylene oxide and a phenol compound in the presence of a reaction initiator which can be decomposed to generate an alcohol, a prepreg and a metal-clad laminate of the invention contain the epoxy resin composition.

Abstract: A method for making a prepreg of an epoxy resin impregnated fiberglass substrate for preparing an electrical laminate provides prolonged shelf life of the prepreg, improved adhesive strength between the prepregs or between a metal foil and the prepreg, and also excellent heat resistance for soldering of the laminate, etc.