Bismaleimide prepreg systems
View Patent ↗Prepreg composite materials that include a fiber layer and a prepreg resin composed of a bismaleimide resin component, a thermoplastic toughening agent and a resin distribution stabilizer. The bismaleimide component is an amorphous mixture of at least three different bismaleimide monomers and a co-curing agent. The prepreg is useful in panel construction where a honeycomb core is sandwiched between two sheets of composite material.
1. A prepreg composite material comprising:
1) a fiber layer; and
2) a prepreg resin comprising:
A) a eutectic bismaleimide resin component comprising:
a) a first bismaleimide monomer selected from the group consisting of N,N′-4,4′-diphenylmethane-bis-maleimide and N,N′-4,4′-diphenyl-ether-bis-maleimide;
b) a second bismaleimide monomer selected from the group consisting of N,N′-2,4-toluene-bis-maleimide, N,N′-2,6-toluene-bis-maleimide and N,N′-meta-phenylene-bis-maleimide; and
c) a third bismaleimide monomer selected from the group consisting of N,N′-2,2,4-trimethylhexane-bis-maleimide and N,N′-4,4′-diphenyl-ether-bis-maleimide; and
d) a comonomer selected from the group consisting of diamines, polyamines and alkenyl aromatic compounds;
B) a thermoplastic toughening agent consisting essentially of polyimide; and
C) a resin distribution stabilizer consisting essentially of polyethylene oxide having a molecular weight of between about 150,000 and about 5,000,000 Daltons, said resin distribution stabilizer being present in a sufficient amount to prevent said prepreg resin from flowing away from said fiber layer during storage of said prepreg composite material.
2. A prepreg composite material according to claim 1 wherein said first bismaleimide monomer is 4,4′-diphenylmethane-bis-maleimide, said second bismaleimide monomer is N,N′-2,4-toluene-bis-maleimide or N,N′-2,6-toluene-bis-maleimide and said third bismaleimide monomer is N,N′-2,2,4-trimethylhexane-bis-maleimide.
3. A prepreg composite material according to claim 1 wherein said first bismaleimide monomer is 4,4′-diphenylmethane-bis-maleimide, said second bismaleimide monomer is N,N′-2,4-toluene-bis-maleimide, said third bismaleimide monomer is N,N′-2,2,4-trimethylhexane-bis-maleimide and said comonomer is o,o′-diallybisphenol A.
4. A prepreg composite material according to claim 3 wherein said polyethylene oxide has a molecular weight of about 2,000,000 Daltons.
5. A prepreg composite material according to claim 4 wherein said prepreg resin comprises:
about 90 weight percent of said bismaleimide resin component;
about 9 weight percent of said thermoplastic toughening agent; and
about 1 weight percent of said resin distribution stabilizer.
6. A composite material comprising a prepreg according to claim 5 that has been cured.
7. A prepreg composite material according to claim 5 wherein said fiber layer comprises carbon fibers.
8. A prepreg composite material according to claim 3 wherein said prepreg resin comprises:
about 90 weight percent of said bismaleimide resin component;
about 9 weight percent of said thermoplastic toughening agent; and
about 1 weight percent of said resin distribution stabilizer.
9. A composite material comprising a prepreg according to claim 8 that has been cured.
10. A prepreg composite material according to claim 8 wherein said fiber layer comprises carbon fibers.
11. A prepreg composite material according to claim 1 wherein said comonomer is a bis(alkenylphenol).
12. A prepreg composite material according to claim 11 wherein said bis(alkenylphenol) is selected from the group consisting of o,o′-diallylbisphenol A and o,o′-dipropenylbisphenol A.
13. A prepreg composite material according to claim 1 wherein said polyethylene oxide has a molecular weight of about 2,000,000 Daltons.
14. A prepreg composite material according to claim 1 wherein said prepreg resin comprises:
about 90 weight percent of said bismaleimide resin component;
about 9 weight percent of said thermoplastic toughening agent; and
about 1 weight percent of said resin distribution stabilizer.
15. A composite material comprising a prepreg according to claim 14 that has been cured.
16. A prepreg composite material according to claim 14 wherein said fiber layer comprises carbon fibers.
17. A prepreg composite material according to claim 1 wherein said fiber layer comprises carbon fibers.
18. A composite material comprising a prepreg according to claim 1 that has been cured.