Abstract: Provided is a heat-curable resin composition capable of being turned into a cured product having a low relative permittivity, a low dielectric tangent, an excellent adhesiveness and a high resistance. The heat-curable resin composition contains: (A) a citraconimide compound; (B) an epoxy resin; (C) an epoxy resin curing agent; and (D) a curing accelerator.

Abstract: Provided is a resin composition that has a low viscosity before curing, and is capable of being turned into a cured product having superior dielectric properties (low relative permittivity and low dielectric tangent), a low elastic modulus and also an excellent heat resistance. The resin composition is a heat-curable citraconimide resin composition containing: (A) a citraconimide compound having a saturated or unsaturated divalent hydrocarbon group(s) having 6 to 100 carbon atoms; (B) an epoxy resin having at least two epoxy groups in one molecule; and (C) a reaction promoter, wherein a mass ratio between the components (A) and (B) is (A):(B)=99:1 to 1:99.

Abstract: Provided is an adhesive composition for a flexible printed-wiring board (FPC) that has low dielectric properties, a high adhesion strength to low-dielectric resin films (LCP or MPI) and a copper foil, and an excellent moisture resistance and reflow resistance. This adhesive composition contains: (A) 100 parts by mass of a maleimide compound having at least two maleimide groups in one molecule, having a number average molecular weight of greater than 4,000, and having at least one divalent organic group selected from a dimer acid skeleton, a linear alkylene group having not less than 6 carbon atoms, and a linear alkenylene group having not less than 6 carbon atoms; (B) 0.1 to 15 parts by mass of an epoxy resin having at least two epoxy groups in one molecule; and (C) 0.1 to 5 parts by mass of a diaminotriazine ring-containing imidazole.