Bis-maleimide-epoxy compositions and prepregs

A cured composition comprised of an admixture of an unsaturated polyimide essentially free of terminal amine groups and epoxy resin wherein said admixture of said polyimide and said epoxy resin has been heated to temperature for a period of time sufficient to polymerize said polyimide but not sufficient to substantially homopolymerize said epoxy resin and, after such polymerization of said polyimide, said admixture has been further heated to a higher temperature for a period of time sufficient to cause said epoxy resin to polymerize.

A prepreg comprising a fibrous material coated or impregnated with a composition comprising an admixture of an unsaturated polyimide essentially free of terminal amine groups and an epoxy having a homopolymerization temperature greater than the temperature at which the polyimide polymerizes.

An article of manufacture comprising a cured composition comprising an admixture of an unsaturated polyimide essentially free of terminal amine groups and an epoxy having a homopolymerization temperature greater than the temperature at which the polyimide polymerizes, wherein said article is cured by heating said article at a first temperature to polymerize said polyimide while said epoxy functions as a diluent, and subsequently heating said at a second temperature to substantially homopolymerize said epoxy.

A process for polymerizing an unsaturated polyimide with an epoxy resin, said process comprising:

• admixing said polyimide and said epoxy to form an admixture;
• first heating said admixture to initiate the polymerization of said polyimide in said epoxy which acts substantially as a diluent;
• subsequently further heating said admixture to substantially homopolymerize said epoxy, thereby creating in situ reaction groups that crosslink the epoxy into the polyimide backbone.

A composition comprising from 30 to 70 parts by weight of a polyimide

• and from 25 to 40 parts by weight of an epoxy having the formula:
• ##STR30##

A composition comprising from 30 to 70 parts by weight of a polyimide having the formula:

• ##STR31## and from 25 to 45 parts by weight of an epoxy having the formula:
• ##STR32##

An resinous composition comprising an admixture of an unsaturated polyimide essentially free of terminal amine groups and a a glycidyl amine epoxy having a viscosity less than about 10,000 cp at 120.degree. F. and a homopolymerization temperature greater than the temperature at which the polyimide polymerizes.

A resinous composition comprising an admixture of an unsaturated polyimide essentially free of terminal amine groups and an epoxy having a viscosity less than about 10,000 cp at 120.degree. F. and a homopolymerization temperature greater than the temperature at which the polyimide polymerizes.