Thermosetting resin, and thermosetting composition comprising the same, and then the resulting molded article

PROBLEM TO BE SOLVED: To provide a thermosetting resin having excellent dielectric characteristics and flexibility more improved than the conventional one, and to provide a thermosetting resin composition containing the resin, a molded product obtained therefrom, a substrate material or the like for electronic equipment. SOLUTION: The thermosetting resin comprises a polymer having a dihydrobenzoxazine ring structure represented by general formula (I) (wherein, Ar 1 is a tetravalent aromatic group; R 1 is an organic group comprising an aliphatic group having an ether bond; and n is an integer of 2-500) in the main chain. The thermosetting composition containing the resin, the molded product obtained therefrom and the like are also provided. COPYRIGHT: (C)2008,JPO&INPIT