Curable compositions

1. A curable composition, comprising:

an epoxy resin;

a non-halogen flame retardant agent comprising at least two of an aryl-cyanato group and at least two of a phosphorus group; and

a styrene and maleic anhydride copolymer;

where the non-halogen flame retardant agent is represented by a compound of Formula (I):

wherein m is an integer from 1 to 20;

wherein n is an integer from 0 to 20 with the proviso that when n is 0 then m is an integer from 2 to 20;

wherein each X is selected from the group consisting of sulfur, oxygen, a lone electron pair, and combinations thereof;

wherein each R 1 and R 2 is independently a hydrogen, an aliphatic moiety having 1 to 20 carbon atoms, or aromatic hydrocarbon moiety having 6 to 20 carbon atoms, where the aliphatic moiety and the aromatic hydrocarbon moiety can be joined to form a cyclic structure;

wherein R 3 is selected from the group consisting of a hydrogen, an aliphatic moiety having 1 to 20 carbon atoms, an aromatic hydrocarbon moiety having 6 to 20 carbon atoms, R 4 R 5 P(═X)CH 2 —, and ROCH 2 —, where R is an aliphatic moiety having 1 to 20 carbon atoms; and

wherein each R 4 and R 5 is independently an aliphatic moiety having 1 to 20 carbon atoms, an aromatic hydrocarbon moiety having 6 to 20 carbon atoms, where the aliphatic moiety and the aromatic hydrocarbon moiety can be joined to form a cyclic structure, RX—, or wherein R 4 and R 5 together are —Ar 2 X—; and

wherein each Ar 1 and Ar 2 is independently a benzene, a naphthalene, or a biphenyl.

2. The curable composition of claim 1 , wherein for the compound of Formula (I) X is oxygen, n is 1, m is 1, each R 1 and R 2 is a methyl group, R 3 is R 4 R 5 P(═X)CH 2 —, and R 4 and R 5 together are —Ar 2 X—, wherein Ar 2 is biphenyl such that R 4 R 5 P(═X)— is represented by a compound of Formula (II):

3. The curable composition of claim 1 , wherein for the compound of Formula (I) X is oxygen, n is 0, m is 2 or 3, R 3 is R 4 R 5 P(═X)CH 2 —, and R 4 and R 5 together are —Ar 2 X—, wherein Ar 2 is biphenyl such that R 4 R 5 P(═X)— is represented by a compound of Formula (II):

4. The curable composition of claim 1 , where Ar 1 is benzene.

5. The curable composition of claim 1 , where an epoxy group of the epoxy resin to a maleic anhydride group of the styrene and maleic anhydride copolymer has a molar ratio within a range of from 1.0:1.0 to 2.6:1.0.

6. The curable composition of claim 1 , where an epoxy group of the epoxy resin to a maleic anhydride group of the styrene and maleic anhydride copolymer has a molar ratio within a range of from 1.3:1.0 to 1.8:1.0.

7. The curable composition of claim 1 , where an epoxy group of the epoxy resin to a maleic anhydride group of the styrene and maleic anhydride copolymer has a molar ratio within a range of from 1.3:1.0 to 1.4:1.0.

8. The curable composition of claim 1 , where the curable composition has a phosphorus content within a range of from 0.1 weight percent to 3.5 weight percent based on a total weight of the curable composition.

9. The curable composition of claim 1 , where the curable composition has a phosphorus content within a range of from 2.2 weight percent to 3.0 weight percent based on the total weight of the curable composition.

10. The curable composition of claim 1 , where the styrene and maleic anhydride copolymer has a molar ratio of styrene to maleic anhydride within a range of from 1:1 to 8:1.

11. The curable composition of claim 10 , where the non-halogen flame retardant agent is 10 weight percent to 60 weight percent of the total weight of the curable composition.

12. The curable composition of claim 11 , where the styrene and maleic anhydride copolymer is 20 weight percent to 60 weight percent of the total weight of the curable composition.

13. The curable composition of claim 1 , where the non-halogen flame retardant agent is 1 weight percent to 90 weight percent of a total weight of the curable composition.

14. The curable composition of claim 1 , where the styrene and maleic anhydride copolymer is 10 weight percent to 90 weight percent of a total weight of the curable composition.

15. A prepreg that includes a reinforcement component and the curable composition of claim 1 .

16. A method of preparing a curable composition, comprising:

providing an epoxy resin; and

reacting the epoxy resin with a non-halogen flame retardant agent and a copolymer of styrene with maleic anhydride, wherein the non-halogen flame retardant agent comprises at least two of an aryl-cyanato group and at least two of a phosphorus group and the non-halogen flame retardant agent is formed by condensing an etherified resole with (H—P(═X)R 4 R 5 ) to form a reaction product, wherein each R 4 and R 5 is independently an aliphatic moiety having 1 to 20 carbon atoms, an aromatic hydrocarbon moiety having 6 to 20 carbon atoms, where the aliphatic moiety and the aromatic hydrocarbon moiety can be joined to form a cyclic structure, RX—, or wherein R 4 and R 5 together are —Ar 2 X—; wherein X is sulfur, oxygen, or a lone electron pair; and wherein Ar 2 is benzene, naphthalene, or biphenyl and R is an aliphatic moiety having 1 to 20 carbon atoms; and

converting the reaction product to the non-halogen flame retardant agent with a cyanogen halide and a base.

17. The method of claim 16 , wherein R 4 and R 5 together are —Ar 2 X—, X is oxygen and Ar 2 is biphenyl to give 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.