Composition for casting material

PURPOSE: To obtain a composition capable of providing a cured product excellent in crack resistance and toughness while keeping excellent characteristics of epoxy resin itself such as dimensional stability, mechanical strength, electrical insulating properties, heat resistance, water resistance or chemical resistance. CONSTITUTION: The objective composition is characterized by dispersing (a) a crosslinked rubbery copolymer in (b) a compound containing an epoxy group in granular state. As the component (a), a compound containing an epoxy group is used without specific limitation. As the concrete example of the component (b), mention may be made of a bisphenol skeleton-containing polyol type epoxy compound or a polyurethane skeleton-containing epoxy compound. The crosslinked rubbery copolymer which is the component (b) has a rubbery elasticity at ordinary temperature and its glass transition temperature (Tg) is normally ≤25°C, preferably ≤0°C, further preferably -20°C. COPYRIGHT: (C)1993,JPO&Japio