New environmentally conscious flame-retarding plastics for electronics products

Flame-retardant plastics containing no toxic flame-retarding additives such as halogen (bromine) compounds and phosphorus compounds have been developed for electronic products. A polycarbonate (PC) resin containing a silicone derivative as a new safer flame-retarding aromatic has been developed for use in housings. A special silicone with a branched chain structure and with an aromatic group in the chain was found to be greatly effective in retarding the combustion of PC resin. The PC resin containing the silicone shows other good properties, such as strength, moldability and heat resistance as well as high flame retardance and also good recyclability. Moreover, the authors have developed a new flame-retardant epoxy resin compound containing no flame-retarding additives as a molding resin for electronic parts. A self-extinguishing network structure of the epoxy resin compound was obtained by using an aromatic epoxy resin and a phenol derivative hardener; both of which have multi-aromatic groups in their main chain. The high flame retardance was achieved by the formation of a foam layer during combustion. The epoxy resin compound has other good properties (resistance to humidity, solder heating and thermal cycles, etc.) as well as high flame retardance and can be used as a high quality molding resin for LSIs.