PURPOSE: To obtain a thermosetting resin composition excellent in dielectric properties by mixing a compound prepared by previously reacting an epoxy resin with a halogenated bisphenol compound with a polyisocyanate compound and an epoxy curing agent.
CONSTITUTION: This composition is one essentially consisting of a compound prepared by previously reacting an epoxy resin represented by formula I with a halogenated bisphenol compound represented by formula II, a polyisocyanate compound having at least two cyanate groups in the molecule and an epoxy curing agent and having a content of the polycyanate compound of 5-50wt.%. In the formula, n is the average number of repeating units and is 0-10; R1 is H or a 1-9C alkyl; P is at least a 4-9C alkyl or the like, is 1-3; R2 is H or methyl; X and X' are each a halogen; k and l are each 1-4; R3 is H or the like; Q and Q' are each a 1-9 C alkyl or the like; and j and m are each 0-4.
UEDA YOICHI
SHIBATA MITSUHIRO
