Insulating material and a circuit substrate in use thereof

摘要

An insulating material characterized by that said insulating material is made by curing a mixture composed of a bisphenol A type epoxy resin having purity which is equal to or more than 90% and an organic filler, the thermal conductivity thereof is in a range of 5.0x10-3 to 18.0x10-3 (cal/ DEG C.xcmxsec) and the glass transition temperature thereof is in a range of 164 DEG to 240 DEG C.