ABSTRACT
The epoxy resins used were 4,4′-diglycidyloxy-3, 3′,5,5′-tetramethyl biphenyl (JER Co., YX-4000H) and diglycidyl ether of brominated bisphenol A (Sumitomo Co., ESB 400). The hardener was phenol-aralkyl resin (Mitsui Chemical Inc., XLC-2 L). The catalyst triphenylphosphine (TPP), was obtained from Hooko co. and triphenylphosphine-1,4-benzoquinone (TPP-BQ) was synthesized in the authors’ laboratory. The filler was fused silica with a mean particle size (D50) of 20 μm (Tatsumori Co.). The coupling agent was glycidoxypropyl trimethoxysilane (Shin-Etsu Chemical Co.). The release agent was the ethylene glycol ester of montanic acid (Hoechst Co.). The colorant was carbon black (Cabot Co., CM 800). The materials were thoroughly kneaded using a two-roll mill, in which the cold roller was operated at 15°C and the hot roller was operated at 120°C. After mixing, EMC was cooled and pulverized. Each sample was stored in a refrigerator at 4°C.
