Flame retardant compositions

1. A flame retardant composition comprising:

(a) 81 to 99.99 weight percent of a thermoplastic resin, thermoset resin, thermoplastic resin blend, or thermoset resin blend which upon burning forms a char; and

(b) 0.01-19 weight percent of a silsesquioxane resin having a weight average molecular weight of greater than 300 and having the average molecular formula:

(R 3 SiO 1/2 ) a (R 2 SiO 2/2 ) b (RSiO 3/2 ) c (SiO 4/2 ) d (RO 1/2 ) e (OH 1/2 ) f

wherein each R is hydrogen, methyl, or phenyl, a and b are zero or positive numbers and the value of a+b is greater than zero, c is a positive number, d, e and f are zero or positive numbers with the provisos that the copolymer comprises at least 40 mole percent of RSiO 3/2 units, the copolymer comprises less than 10 mole percent SiO 4/2 units, greater than 30 mole percent of the silicon-bonded R groups are silicon-bonded phenyl groups, at least 13 mole percent of the silicon-bonded R groups are silicon-bonded hydrogen atoms, the content of silicon-bonded hydroxyl groups is equal to or less than 2 weight percent, and the content of silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy is equal to or less than 5 weight percent.

2. A composition according to claim 1 , wherein (a) is selected from polycarbonates, polyamides, polyesters, blends of polycarbonates with other polymers, polyphenylene ether, polyphenyleneoxide, blends of polyphenylene ether with styrenics, blends of polyphenyleneoxide with styrenic materials, polyaramids, polyimides, phenyl-containing resins having a rigid rod structure, styrenic materials, polyacrylates, styrene-acrylonitrile resins, halogenated plastics, polyketones, polymethylmethacrylate (PMMA), thermoplastic elastomers, cellulosics, rayon, or polylactic acid.

3. A composition according to claim 2 , wherein the styrenic materials are selected from acrylonitrile-butadiene-styrene, polystyrene, or high-impact polystyrene.

4. A composition according to claim 1 , wherein (a) is selected from epoxy resins, phenolic resins, urethane elastomers, or blends thereof.

5. A composition according to claim 1 , wherein (b) comprises 60 to 90 mole percent of RSiO 3/2 units, less than 5 mole percent of SiO 4/2 units, 50 to 80 mole percent silicon-bonded phenyl groups, 0.5 to 1.2 weight percent silicon-bonded hydroxyl groups, and less than 5 percent silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy.

6. A composition according to claim 1 , wherein (b) is

(Me 2 HSiO 1/2 ) a (PhMeSiO 2/2 ) b (Me 2 SiO 2/2 ) b (PhSiO 3/2 ) c ,

(MeHSiO 2/2 ) b (PhSiO 3/2 ) c , or

(Me 3 SiO 1/2 ) a (MeHSiO 2/2 ) b (PhSiO 3/2 ) c .

7. A composition according to claim 1 , wherein the composition further comprises a sodium-containing catalyst.

8. A composition according to claim 1 , wherein the compositions further comprise polytetrafluoroethylene powder.

9. A composition according to claim 1 , wherein (a) is selected from polycarbonates, polycaprolactam, polylauryllactam, polyhexamethyleneadipamide, polyhexamethylenedodecanamide, blends of Nylons with other polymers, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, polycarbonate-acrylonitrile-butadiene-styrene blends, polycarbonate-polybutylene terephthalate blends, polyphenylene ether, polyphenyleneoxide, polyphenylene sulfide, polyether sulphone, polyethylene sulfide, acrylonitrile-butadiene-styrene, polystyrene, high-impact polystyrene, styrene-acrylonitrile resins, polyvinyl chloride, fluoroplastics, polymethylmethacrylate, thermoplastic urethanes, thermoplastic vulcanizates, or styrene ethylene butylene styrene copolymer.

10. A composition according to claim 9 , wherein (b) comprises 60 to 90 mole percent of RSiO 3/2 units, less than 5 mole percent of SiO 4/2 units, 50 to 80 mole percent silicon-bonded phenyl groups, 0.5 to 1.2 weight percent silicon-bonded hydroxyl groups, and less than 5 percent silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy.

11. A composition according to claim 9 , wherein (b) is

(Me 2 HSiO 1/2 ) a (PhMeSiO 2/2 ) b (Me 2 SiO 2/2 ) b (PhSiO 3/2 ) c ,

(MeHSiO 2/2 ) b (PhSiO 3/2 ) c , or

(Me 3 SiO 1/2 ) a (MeHSiO 2/2 ) b (PhSiO 3/2 ) c .

12. A composition according to claim 10 , wherein the composition further comprises a sodium-containing catalyst.

13. A composition according to claim 11 , wherein the composition further comprises a sodium-containing catalyst.

14. A composition according to claim 12 , wherein the compositions further comprise polytetrafluoroethylene powder.

15. A composition according to claim 13 , wherein the compositions further comprise polytetrafluoroethylene powder.

16. A composition according to claim 1 wherein (b) comprises 60 to 90 mole percent of RSiO 3/2 units, less than 5 mole percent of SiO 4/2 units, 50 to 80 mole percent silicon-bonded phenyl groups, 13 to 20 mole percent silicon-bonded hydrogen atoms, 0.5 to 1.2 weight percent silicon-bonded hydroxyl groups, and less than 5 percent silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy.

17. A composition according to claim 1 wherein (b) comprises 60 to 90 mole percent of RSiO 3/2 units, less than 5 mole percent of SiO 4/2 units, 50 to 80 mole percent silicon-bonded phenyl groups, 13.7 to 20 mole percent silicon-bonded hydrogen atoms, 0.5 to 1.2 weight percent silicon-bonded hydroxyl groups, and less than 5 percent silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy.

18. A composition according to claim 14 wherein (b) comprises 60 to 90 mole percent of RSiO 3/2 units, less than 5 mole percent of SiO 4/2 units, 50 to 80 mole percent silicon-bonded phenyl groups, 13.7 to 20 mole percent silicon-bonded hydrogen atoms, 0.5 to 1.2 weight percent silicon-bonded hydroxyl groups, and less than 5 percent silicon-bonded alkoxy groups where the alkoxy group is methoxy or ethoxy.

19. A composition according to claim 1 wherein (b) comprises 13 to 20 mole percent silicon-bonded hydrogen atoms.

20. A composition according to claim 1 wherein (b) comprises 13.7 to 20 mole percent silicon-bonded hydrogen atoms.