Abstract: A prepreg having low water absorption, and having remarkably suppressed deterioration in insulation resistance over time, and further having excellent heat resistance, a metal foil-clad laminate using the prepreg, and a printed wiring board using the metal foil-clad laminate are provided. A prepreg of the present invention is obtained by impregnating or coating a base material (D) with a resin composition comprising: a naphthol-modified dimethylnaphthalene formaldehyde resin (A); an epoxy resin (B) having an epoxy equivalent of 200 to 400 g/eq.; and an inorganic filler (C).

Abstract: A method for efficiently producing a cyanogen halide with suppressed side effects, and a method for producing a high-purity cyanate ester compound at a high yield includes contacting a halogen molecule with an aqueous solution containing hydrogen cyanide and/or a metal cyanide, so that the hydrogen cyanide and/or the metal cyanide is allowed to react with the halogen molecule in the reaction solution to obtain the cyanogen halide, wherein more than 1 mole of the hydrogen cyanide or the metal cyanide is used based on 1 mole of the halogen molecule, and when an amount of substance of an unreacted hydrogen cyanide or an unreacted metal cyanide is defined as mole (A) and an amount of substance of the generated cyanogen halide is defined as mole (B), the reaction is terminated in a state in which (A):(A)+(B) is between 0.00009:1 and 0.2:1.

Abstract: A method for efficiently producing a cyanogen halide with suppressed side effects, and a method for producing a high-purity cyanate ester compound at a high yield includes contacting a halogen molecule with an aqueous solution containing hydrogen cyanide and/or a metal cyanide, so that the hydrogen cyanide and/or the metal cyanide is allowed to react with the halogen molecule in the reaction solution to obtain the cyanogen halide, wherein more than 1 mole of the hydrogen cyanide or the metal cyanide is used based on 1 mole of the halogen molecule, and when an amount of substance of an unreacted hydrogen cyanide or an unreacted metal cyanide is defined as mole (A) and an amount of substance of the generated cyanogen halide is defined as mole (B), the reaction is terminated in a state in which (A):(A)+(B) is between 0.00009:1 and 0.2:1.

Abstract: There are provided a prepreg having low water absorption, and of which deterioration in insulation resistance over time is remarkably suppressed, and further having excellent heat resistance, a metal foil-clad laminate using the prepreg, and a printed wiring board using the metal foil-clad laminate. A prepreg of the present invention is obtained by impregnating or coating a base material (D) with a resin composition comprising: a naphthol-modified dimethylnaphthalene formaldehyde resin (A); an epoxy resin (B) having an epoxy equivalent of 200 to 400 g/eq.; and an inorganic filler (C).