. . "As the above inorganic powder filler, in the case where an electric insulating property is required, a powder of a non-electrically conductive substance such as a semiconductor or ceramic, including zinc oxide, aluminum oxide, boron nitride, silicon carbide, silica, diamond, or the like can be suitably used, a powder of zinc oxide, aluminum oxide, boron nitride, or silica being more preferred and" . . . . .