Abstract: Provided is an insulating resin material capable of reducing surface roughness of the surface of a cured object, and, when a metal layer is formed on the surface of the cured object, increasing adhesive strength between the cured object and the metal layer. The insulating resin material of the present invention includes a thermosetting resin, a curing agent, a first inorganic filler surface-treated with a first silane coupling agent, and a second inorganic filler surface-treated with a second silane coupling agent. When absolute difference between SP values of a most-abundantly contained thermosetting resin and an organic group of the first silane coupling agent is defined as SP(A), and when absolute difference between SP values of the most-abundantly contained thermosetting resin and an organic group of the second silane coupling agent is defined as SP(B); (SP(A)?SP(B)) is not smaller than 0.5 but not larger than 3.5.

Abstract: A preliminary-cured material permits reduced surface roughness of a roughening-treated surface, and increase of an adhesive strength between a cured object and a metal layer. The preliminary-cured material is obtained by advancing curing of an epoxy resin material that contains an epoxy resin, a curing agent, and a silica. The preliminary-cured material includes a first principal surface to be roughening-treated, and a second principal surface. The silica includes a first small particle-diameter silica whose particle diameter is not smaller than 0.01 ?m but smaller than 0.5 ?m, and a second large particle-diameter silica whose particle diameter is not smaller than 0.5 ?m but not larger than 20 ?m. The first small particle-diameter silica is localized to exist in large quantity on a side of the first principal surface, and the second large particle-diameter silica is localized to exist in large quantity on a side of the second principal surface.

Abstract: Provided is an insulating resin material capable of reducing surface roughness of the surface of a cured object, and, when a metal layer is formed on the surface of the cured object, increasing adhesive strength between the cured object and the metal layer. The insulating resin material of the present invention includes a thermosetting resin, a curing agent, a first inorganic filler surface-treated with a first silane coupling agent, and a second inorganic filler surface-treated with a second silane coupling agent. When absolute difference between SP values of a most-abundantly contained thermosetting resin and an organic group of the first silane coupling agent is defined as SP(A), and when absolute difference between SP values of the most-abundantly contained thermosetting resin and an organic group of the second silane coupling agent is defined as SP(B); (SP(A)?SP(B)) is not smaller than 0.5 but not larger than 3.5.

Abstract: A preliminary-cured material permits reduced surface roughness of a roughening-treated surface, and increase of an adhesive strength between a cured object and a metal layer. The preliminary-cured material is obtained by advancing curing of an epoxy resin material that contains an epoxy resin, a curing agent, and a silica. The preliminary-cured material includes a first principal surface to be roughening-treated, and a second principal surface. The silica includes a first small particle-diameter silica whose particle diameter is not smaller than 0.01 ?m but smaller than 0.5 ?m, and a second large particle-diameter silica whose particle diameter is not smaller than 0.5 ?m but not larger than 20 ?m. The first small particle-diameter silica is localized to exist in large quantity on a side of the first principal surface, and the second large particle-diameter silica is localized to exist in large quantity on a side of the second principal surface.