Use of alumina trihydrate in composites

1. A composition comprising:

alumina trihydrate, from greater than 0 to about 2 wt. % expandable graphite based on the weight of the alumina trihydrate; and

a plurality of reinforcing fibers comprising from about 15 wt. % to about 50 wt. % of the composition, wherein from about 60% to about 90% of the expandable graphite has a particle size from about 45 μm to about 150 μm.

2. The composition of claim 1 , wherein the expandable graphite is present at a level from greater than 0 to about 1 wt. % based on the weight of alumina trihydrate.

3. The composition of claim 1 , wherein the expandable graphite is present at a level from greater than 0 to about 0.5 wt. %, based on the weight of the alumina trihydrate.

4. A composite comprising:

a polymer;

a metal hydroxide;

from greater than 0 to about 2 wt. % expandable graphite based on the weight of the metal hydroxide; and

a plurality of reinforcing fibers, wherein the plurality of reinforcing fibers comprise from about 15 wt. % to about 50 wt. % of the composite, and wherein from about 60% to about 90% of the expandable graphite has a particle size from about 45 μm to about 150 μm.

5. The composite of claim 4 , wherein the metal hydroxide comprises alumina trihydrate.

6. The composite of claim 4 , wherein the metal hydroxide comprises magnesium hydroxide.

7. The composite of claim 4 , wherein the polymer comprises a thermoset polymer.

8. The composite of claim 4 , wherein the polymer comprises a polyester.

9. The composite of claim 4 , wherein the polymer comprises an unsaturated polyester.

10. The composite of claim 4 , wherein the plurality of reinforcing fibers comprise glass fibers.

11. The composite of claim 4 , wherein the metal hydroxide comprises alumina trihydrate and is present at a level of from about 150 phr to about 350 phr.

12. The composite of claim 4 , wherein the metal hydroxide comprises alumina trihydrate, and wherein the expandable graphite is present at a level from greater than 0 to about 1.5 wt. %, based on the weight of alumina trihydrate present in the composite.

13. The composite of claim 4 , wherein the metal hydroxide comprises alumina trihydrate, and wherein the expandable graphite is present at a level from greater than 0 to about 1 wt. %, based on the weight of alumina trihydrate present in the composite.

14. The composite of claim 4 , wherein at least about 90% of the expandable graphite has a particle size from 30 μm to 300 μm.

15. The composite of claim 4 , exhibiting improved performance under ASTM E-84 testing for surface burning characteristics as compared to a composite not comprising expandable graphite.

16. The composite of claim 4 , comprising a lower amount of alumina trihydrate than a comparable composite not comprising expandable graphite and being capable of achieving equivalent performance under ASTM E-84 testing to the comparable composite.

17. The composite of claim 4 , exhibiting equivalent performance under ASTM E-84 testing to a comparable composite comprising about 10% less alumina trihydrate.

18. The composite of claim 4 , exhibiting equivalent performance under ASTM E-84 testing to a comparable composite comprising about 20% less alumina trihydrate.

19. The composite of claim 4 , wherein the metal hydroxide comprises alumina trihydrate, and wherein the expandable graphite is present at a level from greater than 0 to about 0.5 wt. %, based on the weight of alumina trihydrate present in the composite.

20. The composite of claim 4 , exhibiting improved cone calorimeter performance as compared to an identical composite not comprising expandable graphite.

21. The composite of claim 4 , wherein the metal hydroxide comprises alumina trihydrate and is present at a level of from about 200 phr to about 320 phr.

22. The composite of claim 21 , wherein at least about 90% of the expandable graphite has a particle size from 30 μm to 300 μm.

23. A method for preparing a flame retardant composite comprising:

contacting a polymer, alumina trihydrate, from greater than 0 to about 2 wt. % expandable graphite based on the weight of alumina trihydrate, and from about 15 wt. % to about 50 wt. % of a plurality of reinforcing fibers, wherein from about 60% to about 90% of the expandable graphite has a particle size from about 45 μm to about 150 μm.

24. The method of claim 23 , wherein the polymer comprises a thermoset polymer.

25. The method of claim 23 , wherein the polymer comprises a polyester.

26. The method of claim 23 , wherein the plurality of reinforcing fibers comprise glass fibers.

27. The method of claim 23 , wherein alumina trihydrate is present at a level of from about 150 phr to about 350 phr.

28. The method of claim 23 , wherein the expandable graphite is present from greater than 0 to about 1.5 wt. %, based on the weight of alumina trihydrate in the composite.

29. The method of claim 23 , wherein the expandable graphite is present from greater than 0 to about 1 wt. %, based on the weight of alumina trihydrate in the composite.

30. The method of claim 23 , wherein at least about 90% of the expandable graphite has a particle size from 30 μm to 300 μm.

31. The method of claim 23 , wherein the polymer and at least a portion of the expandable graphite is contacted prior to contacting with the plurality of reinforcing fibers.

32. A composition produced by the method of claim 23 .

33. The method of claim 23 , wherein the expandable graphite is present from greater than 0 to about 0.5 wt. %, based on the weight of alumina trihydrate in the composite.

34. A composite comprising:

a thermoset polymer;

alumina trihydrate;

from greater than 0 to about 1 wt. % expandable graphite based on the weight of the alumina trihydrate, wherein at least about 90% of the expandable graphite has a particle size from 30 μm to 300 μm, and from about 60% to about 90% of the expandable graphite has a particle size from about 45 μm to about 150 μm; and

from about 15 wt. % to about 50 wt. % of the composite of a plurality of reinforcing fibers comprising glass fibers.