電子部品用エポキシ樹脂組成物からの熱分解による有価物の回収技術

Abstract

A pyrolysis-based technology was applied to recover high purity silica filler from epoxy resin compounds (molding resins) for electronic components, and to reuse it as a filler in the present paper. Molding resins mainly contain epoxy resin, harder, silica filler (70-85 wt %) and flame retardant consisting of brominated epoxy resin and antimony trioxide. Most effective conditions to reduce impurities in the recovered silica were found as heat around 1,000-1,100 °C and to keep oxygen concentration 5-10 vol. %. On the basis of these results, we have developed a practical process for recovering silica filler from molding resins using a roller kiln-type furnace. The recovered silica achieved a purity of C < 0.01 wt %, Sb < 0.4 wt %, and PO43- < 0.002 wt %. A jet-mil treatment was effective to grind the aggregates of recovered silica powder and to increase the reactivity of its surfaces. The recovered silica treated with the jet-mill showed good properties as a filler for a cast insulating epoxy resin compound. A secondary combustion method was successfully applied to the decomposition of the combustion gas. The treatment of the gas by heating at 1,100 °C decreased the toxic organic bromine compounds to a safe level and converted the antimony tribromide to diantimony trioxide, which could be collected by a dry recovery process at high recovery rate.