Electrical substrate containing single resin thermosetting compositions

摘要

An electrical substrate material e.g. for microwave and digital circuits comprises a thermosetting matrix of polybutadiene or polyisoprene in an amount of 25 to 50 volume %; a woven glass fabric in an amount of 10 to 40 volume %; a particulate, preferably ceramic filler, in an amount of from 5 to 60 volume %; and preferably a flame retardant. Importantly, the composition comprises only a single resin, i.e., polybutadiene or polyisoprene. A peroxide cure initiator and/or crosslinking agent may optionally be added. The presence of a very high surface area particulate filler, preferably fumed silica, is also preferred, in that its presence results in a prepreg which has very little tackiness and can therefore be easily handled by operators. This low tackiness feature allows for the use of conventional automated layup processing, including foil cladding, using one or more known roll laminators.