POLYMERS WITH IMIDE GROUPS PREPARED FROM STERICALLY HINDERED DIAMINES

Novel thermostable imido copolymers, well adapted for the production of prepregs useful in the fabrication of multilayer circuits, are prepared by copolymerizing (a) at least one N,N'-bis-maleimide with (b) at least one sterically hindered diprimary diamine, (c) optionally, at least one ethylenically unsaturated non-halogenated comonomer other than a bis-imide (a), (d) optionally, a free radical polymerization initiator, (e) at least one comonomer including a chlorinated or brominated epoxy resin, an N,N'-alkylene-bis-tetrahalogenophthalimide, a compound containing two phenyl radicals directly joined va a single valence bond, a divalent radical or a bridging atom, wherein such compound each phenyl radical is substituted by a (meth)allyloxy radical and by at least two chlorine or bromine atoms, and/or a non-halogenated epoxy resin, and (f) at least one alkenylphenol.