| 摘要 |
PURPOSE:The titled curing agent which can be easily mixed with an epoxy resin to form a composition having a long pot life and excellent workability and being curable into a product excellent in heat and weather resistances, comprising an exo isomer of a specified acid anhydride or a mixture of its endo and exo isomers. CONSTITUTION:A curing agent for an epoxy resin comprising an exo isomer or a mixture of endo and exo isomers of bicyclo[2,2,1]heptanedicarboxylic anhydride or methylbicyclo[2,2,1]heptanedicarboxylic anhydride. When an acid anhydride is used as a curing agent for an epoxy resin, the pot life is longer than that obtained when an amine curing agent is used, and a cured product excellent in electrical properties and heat resistance can be obtained. On the other hand, when the endo isomer of bicyclo[2,2,1]heptanedicarboxylic anhydride is used as a curing agent, it can hardly be mixed with a liquid epoxy resin. When this mixing is performed at a temperature higher than its m.p., the pot life is shortened unfavorably. By using the curing agent of this invention, it is possible to obtain a cured product freed from these drawbacks.
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