Masatoshi Iji* and Sadahiko Yokoyama*

* Ecology-Based Systems Research Laboratory, Resource and Environmental Protection Laboratories, NEC Corporation

+ Correspondence should be addressed to Masatoshi Iji:
(4-1-1Miyazaki, Miyamae, Kawasaki 216 Japan)

Abstract

A recycling technology has been developed for the molding resin residues, which are generated from printed wiring boards (PWBs) production process and consist of cured epoxy resin, glassfiber, and copper circuits. The residues of PWBs were pulverized by crushing and grinding, and the resulting powders were separated into a copper-rich powder and a powder consisting of glassfiber and resin (glassfiber-resin powder) by gravimetric and electrostatic method. More than 90% (maximum 96%) of copper was recoverable as the copper-rich powder from the residue powder of PWBs. This had an average particle size of 100-300[micro]m. The recovered glassfiber-resin powder was found to be useful as a filler to improve the strength properties and the thermal expansion property of epoxy resin products, such as paints and additives.

Key words: printed wiring boards, molding resin residue, recycling, pulverizing, separation