Thermoplastic-toughened cyanate ester resin composites with low heat release properties
View Patent ↗Composite materials that contain thermoplastic-toughened cyanate ester resins as the resin matrix. The composite materials exhibit low levels of heat release when burned. The matrix resins are composed of from 50 to 80 weight percent of a cyanate ester resin component. The matrix resin composition also includes from 10 to 40 weight percent of a thermoplastic blend that is composed of polyetherimide and polyamideimide. The epoxy resin composition further includes from 1 to 10 weight percent of a curative agent. The composite materials may be used for primary structures in aircraft and other load-bearing structures.
1. A method for making an uncured composite material, said method comprising the steps of:
providing a resin matrix comprising:
50 to 80 weight percent of a cyanate ester resin component based on the total weight of said resin matrix, said cyanate ester resin component comprising one or more cyanate ester resins that do not contain phosphorous;
10 to 40 weight percent of a thermoplastic blend based on the total weight of said resin matrix, said thermoplastic blend comprising polyetherimide and polyamideimide wherein the weight ratio of polyetherimide to polyamideimide is from 5:1 to 1:1;
1 to 15 weight percent of a fire retardant agent based on the total weight of said resin matrix, said fire retardant agent comprising a phosphorous-containing cyanate ester resin;
1 to 10 weight percent of a curative agent component based on the total weight of said resin matrix, said curative agent component comprising a curative agent for said cyanate ester component; and
combining said resin matrix with a fibrous reinforcement to form said uncured composite material.
2. A method for making an uncured composite material according to claim 1 wherein the resin matrix comprises:
55 to 65 weight percent of said cyanate ester resin component based on the total weight of said resin matrix;
20 to 30 weight percent of said thermoplastic blend based on the total weight of said resin matrix;
8 to 12 weight percent of said fire retardant agent based on the total weight of said resin matrix; and
1 to 5 weight percent of said curative agent component based on the total weight of said resin matrix.
3. A method for making an uncured composite material according to claim 2 wherein the weight ratio of polyetherimide to polyamideimide is from 4:1 to 2:1.
4. A method according to claim 3 which includes the additional step of curing said uncured composite material to form a cured composite part.
5. A method according to claim 2 which includes the additional step of curing said uncured composite material to form a cured composite part.
6. A method for making an uncured composite material according to claim 1 wherein said curative agent for said cyanate ester component is selected from the group consisting of bisphenol sulfone and bisphenol A.
7. A method according to claim 6 which includes the additional step of curing said uncured composite material to form a cured composite part.
8. A method for making an uncured composite material according to claim 1 wherein said fibrous reinforcement comprises unidirectional fibers.
9. A method for making an uncured composite material according to claim 8 which includes the additional steps of chopping said uncured composite material to form chopped pieces of uncured unidirectional fibers and then forming said chopped pieces into an uncured molding compound comprising said chopped pieces that are quasi-isotropically oriented.
10. A method according to claim 9 which includes the additional step of curing said uncured molding compound to form a cured composite part.
11. A method according to claim 10 wherein said cured composite part forms at least part of a primary structure of an aircraft.
12. A method according to claim 8 which includes the additional step of curing said uncured composite material to form a cured composite part.
13. A method according to claim 12 wherein said cured composite part forms at least part of a primary structure of an aircraft.
14. A method for making an uncured composite material according to claim 1 wherein said cyanate ester resin that does not contain phosphorous is selected from the group of cyanate ester resins consisting of bisphenol-E cyanate ester resin, bisphenol-A cyanate ester resin, hexafluorobisphenol-A cyanate ester resin, tetramethylbisphenol-F cyanate ester resin, bisphenol-C cyanate ester resin, bisphenol-M cyanate ester resin, phenol novolac cyanate ester resin and dicyclopentadienyl-bisphenol cyanate ester resin.
15. A method according to claim 14 which includes the additional step of curing said uncured composite material to form a cured composite part.
16. A method for making an uncured composite material according to claim 1 wherein said phosphorous-containing cyanate ester resin comprises from 5 to 15 weight percent phosphorous based on the total weight of the phosphorous-containing cyanate ester resin.
17. A method according to claim 16 which includes the additional step of curing said uncured composite material to form a cured composite part.
18. A method according to claim 1 which includes the additional step of curing said uncured composite material to form a cured composite part.
19. A method according to claim 18 wherein said cured composite part forms at least part of a primary structure of an aircraft.