| 摘要 |
An epoxy resin composition for encapsulating electronic parts is provided which contains an inorganic filler in a large amount and which has a low viscosity and is flowable at ordinary temperature. The composition reconciles reactivity and storage stability, is excellent in suitability for demolding, molded-object appearance, etc., and is reduced in warpage. The epoxy resin composition comprises: (A) 100 parts by weight of an epoxy resin, (B) 50 to 150 parts by weight of an acid anhydride, and (C) 8 to 40 parts by weight of a curing accelerator of the microcapsule-type which satisfies the following: when 10 parts by weight of the curing accelerator is mixed with 100 parts by weight of the epoxy resin (A) and 100 parts by weight of a methyltetrahydroxy acid anhydride as the acid anhydride (B), the mixture has a viscosity increase ratio through 24 hours standing at 25° C. of 1.0 to 2.0 times. The composition further contains (D) fused spherical silica having an average particle diameter of 20 to 40μm in an amount of 88 to 92% by weight of the composition. The composition has a viscosity, as measured at 25° C. under a shear rate of 2.5 (1/s), of 1000 Pa·s or lower.
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