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
• where 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 one or more of said cyanate ester monomer, said prepolymer containing a sym-triazine ring and having an average molecular weight in the range of about 400 to 6,000, and
• (3) a coprepolymer of said cyanate ester monomer and an amine;
• (b) a polyhydantoin resin having a hydantoin ring in the main chain and having the following repeated units:
• ##STR6## (c) at least one compound selected from the group consisting of:
• (1) a polyfunctional maleimide,
• (2) a homoprepolymer of one or more of said maleimide, and
• (3) a coprepolymer of said maleimide and an amine,
• said composition including a mixture of components the (a), the (b), and the (c), a preliminary reaction product of components the (a), the (b), and the (c), a combination of said mixture and said preliminary reaction product, a composition of the (a) an a preliminary reaction product of the (b) and the (c), a combination of the (b), and a preliminary reaction product of the (a) and the (c), or a combination of the (c) and a preliminary reaction product of the (a) and the (b).