Curable resin composition

A curable resin composition comprising:

• (a) at least one cyanate ester compound selected from the group consisting of:
• (1) a polyfunctional aromatic cyanate ester monomer having the formula:
• R--O--C.tbd.N).sub.m
• wherein m is 2 to 5 and R is an aromatic organic group, the cyanate groups being bonded to an aromatic ring of said aromatic organic group,
• (2) a prepolymer of (1), and
• (3) a coprepolymer of (1) and an amine;
• (b) at least one rubber, which is liquid at room temperature or elastic, selected from the group consisting of styrene butadiene rubber, isoprene rubber, polychloroprene rubber, butyl rubber, acrylic rubber, natural rubbers, preliminary reaction products of an epoxy compound and isoprene rubber, preliminary reaction products of a natural rubber and an epoxy compound, rubbers obtained by introducing an acryloyl or a methacryloyl group into isoprene, and acid anhydride moiety-containing rubber obtained by adding a double bond of an unsaturated acid anhydride to isoprene and mixtures thereof,
• (c) at least one compound selected from the group consisting of:
• (1) a polyfunctional maleimide,
• (2) a prepolymer of (1), and
• (3) a coprepolymer of (1) and an amine,
• said composition including a mixture of components (a), (b) and (c), a preliminary reaction product of components (a), (b) and (c), the combination of said mixture and said preliminary reaction product, the combination of (a) and the preliminary reaction product of (b) and (c), the combination of (b) and the preliminary reaction product of (a) and (c), or the combination of (c) and the preliminary reaction product of (a) and (b).