Flame retardant thermoplastic polycarbonate compositions, use and method thereof

1. A thermoplastic composition, consisting essentially of:

about 40 to about 80 wt. % of a polycarbonate resin;

about 2 to about 15 wt. % of an impact modifier;

about 10 to about 25 wt. % of a polysiloxane-polycarbonate copolymer comprising polydiorganosiloxane blocks of formula (6):

wherein each R is independently a C 1-13 monovalent organic radical and D has an average value of about 40 to about 60;

an anti-drip agent; and

about 0.5 to about 20 wt. % of a phosphorus-containing flame retardant, each based on the total combined weight of the thermoplastic composition, exclusive of any filler;

wherein a one-eighth inch (3.18 mm) (±3%) bar comprising the thermoplastic composition has a notched Izod impact strength of at least about 3.6 ft-lb/inch determined in accordance with ASTM D256 at room temperature; and

wherein a sample of the thermoplastic composition having a thickness of about 2.0 mm achieves a UL94 5VB rating in the absence of a brominated and/or chlorinated flame retardant.

2. The composition of claim 1 wherein a sample of the thermoplastic composition having a thickness of about 2.0 mm to about 0.1 mm, when exposed to an open flame, has a flame out time of less than 10 seconds and with no dripping with a probability of first time pass of at least 0.85, in the absence of a brominated and/or chlorinated flame retardant.

3. The composition of claim 1 , wherein a sample of the thermoplastic composition having a thickness of about 1.5 mm achieves a UL94 5VB rating in the absence of a brominated and/or chlorinated flame retardant.

4. The composition of claim 1 , wherein a sample of the thermoplastic composition having a thickness of about 1.2 mm achieves a UL94 5VB rating in the absence of a brominated and/or chlorinated flame retardant.

5. The composition of claim 1 , wherein a sample of the thermoplastic composition having a thickness of about 2.0 mm to about 0.1 mm, when exposed to an open flame, has a flame out time of less than 30 seconds in the absence of a brominated and/or chlorinated flame retardant.

6. The composition of claim 5 , wherein the sample has a flame out time of less than 30 seconds without dripping.

7. The composition of claim 6 wherein the sample has a flame out time of less than 10 seconds.

8. The composition of claim 1 wherein a sample of the thermoplastic composition having a thickness of about 2.0 mm to about 0.1 mm, when exposed to an open flame, has a flame out time of less than 10 seconds and with no dripping with a probability of first time pass of at least 0.85, in the absence of a brominated and/or chlorinated flame retardant.

9. The composition of claim 8 wherein the sample has a thickness of about 0.1 mm to about 1.5 mm.

10. The composition of claim 9 wherein the sample has a thickness of about 0.8 mm to about 1.5 mm.

11. The composition of claim 1 comprising more than 5 wt % polysiloxane-polycarbonate copolymer.

12. The composition of claim 1 comprising about 17.5 to about 25 wt. % polysiloxane-polycarbonate copolymer.

13. The composition of claim 1 , having a melt viscosity at 260° C./1500 sec −1 of about 50 to about 500 Pascal-second, measured in accordance with ISO 11443.

14. The composition of claim 13 wherein a sample of the thermoplastic composition having a thickness of about 0.1 to about 2.0 mm achieves a UL94 V2 rating in the absence of a brominated and/or chlorinated flame retardant.

15. The composition of claim 13 , wherein a sample of the thermoplastic composition having a thickness of about 0.1 mm to about 2.0 mm achieves a UL94 V1 rating in the absence of a brominated and/or chlorinated flame retardant.

16. The composition of claim 13 , wherein a sample of the thermoplastic composition having a thickness of about 0.1 mm to about 2.0 mm achieves a UL94 V0 rating in the absence of a brominated and/or chlorinated flame retardant.

17. The composition of claim 1 , wherein a sample of the thermoplastic composition having a thickness of about 0.1 mm to about 2.0 mm achieves a UL94 V1 rating in the absence of a brominated and/or chlorinated flame retardant.

18. The composition of claim 1 , wherein a sample of the thermoplastic composition having a thickness of about 0.1 mm to about 2.0 mm achieves a UL94 V0 rating in the absence of a brominated and/or chlorinated flame retardant.

19. The composition of claim 1 , wherein a sample of the thermoplastic composition having a thickness of about 1.2 mm to about 2.0 mm achieves a UL94 5 VB rating in the absence of a brominated and/or chlorinated flame retardant.

20. The composition of claim 1 wherein a one-eighth inch (3.18 mm) (±3%) bar comprising the composition has a notched Izod impact strength of at least about 6 ft-lb/inch determined in accordance with ASTM D256 at room temperature.

21. The composition of claim 1 , wherein the polysiloxane-polycarbonate copolymer comprises

aromatic carbonate units of formula (1):

wherein at least about 60 percent of the total number of R 1 groups are aromatic organic radicals and the balance thereof are aliphatic, alicyclic, or aromatic radicals; and

polydiorganosiloxane units of formula (7)

wherein each R is independently a C 1-13 monovalent organic radical;

D has an average value of about 40 to about 60;

each R 2 is independently a divalent C 2 -C 8 aliphatic group;

each M is independently a halogen, cyano, nitro, C 1 -C 8 alkylthio, C 1 -C 8 alkyl, C 1 -C 8 alkoxy, C 2 -C 8 alkenyl, C 2 -C 8 alkenyloxy group, C 3 -C 8 cycloalkyl, C 3 -C 8 cycloalkoxy, C 6 -C 10 aryl, C 6 -C 10 aryloxy, C 7 -C 12 aralkyl, C 7 -C 12 aralkoxy, C 7 -C 12 alkaryl, or C 7 -C 12 alkaryloxy; and

each n is independently 0, 1, 2, 3, or 4.

22. The composition of claim 21 , wherein R 1 is a divalent radical of formula (2):

wherein each of A 1 and A 2 is a monocyclic divalent aryl radical and Y 1 is a bridging radical having one or two atoms that separates A 1 from A 2 ; each R is independently a C 1 -C 13 alkyl, C 1 -C 13 alkoxy, C 2 -C 13 alkenyl, C 2 -C 13 alkenyloxy, C 3 -C 6 cycloalkyl, C 3 -C 6 cycloalkoxy, C 6 -C 10 aryl, C 6 -C 10 aryloxy, C 7 -C 13 aralkyl, C 7 -C 13 aralkoxy, C 7 -C 13 alkaryl, or a C 7 -C 13 alkaryloxy, each R 2 is independently a C 1-C 3 alkylene, each M is independently, and each n is 1.

23. The composition of claim 22 , wherein each Y 1 is independently —O—, —S—, —S(O)—, —S(O 2 )—, —C(O)—, methylene, cyclohexyl-methylene, 2-[2.2.1]-bicycloheptylidene, ethylidene, isopropylidene, neopentylidene, cyclohexylidene, cyclopentadecylidene, cyclododecylidene, or adamantylidene; each R is independently a C 1-8 alkyl, trifluoropropyl, C 1 -8 cyanoalkyl, phenyl, chlorophenyl, or tolyl group; each M is a methyl, ethyl, propyl, methoxy, ethoxy, propoxy, phenyl, chlorophenyl, or tolyl group; R 2 is a trimethylene group; and R is a C 1-8 alkyl, trifluoropropyl, C 1-8 cyanoalkyl, phenyl, chlorophenyl, or tolyl.

24. The composition of claim 23 wherein A 1 and A 2 are each a divalent phenyl group; Y 1 is methylene, cyclohexylidene, or isopropylidene; M is methoxy; and R is methyl, or a mixture of methyl and trifluoropropyl, or a mixture of methyl and phenyl.

25. The composition of claim 1 , further comprising a thermoplastic polymer having a Tg of greater than about 20° C., and comprising units derived from a monovinyl aromatic compound, itaconic acid, acrylamide, N-substituted acrylamide methacrylamide, maleic anhydride, maleimide, N-alkyl, aryl or haloaryl substituted maleimide, a glycidyl (meth)acrylate, a monomer of the general formula (12):

wherein R is hydrogen, C 1 -C 5 alkyl, bromo, or chloro and X c is cyano, C 1 -C 12 alkoxycarbonyl, or C 1 -C 12 aryloxycarbonyl, or a combination comprising at least one of the foregoing monomers.

26. The composition of claim 1 , further comprising a thermoplastic polymer having a Tg of greater than about 20° C., and comprising units derived from styrene, 3-methylstyrene, 3,5-diethylstyrene, 4-n-propylstyrene, alpha-methylstyrene, alpha-methyl vinyltoluene, alpha-chloro styrene, alpha-bromostyrene, dichlorostyrene, dibromostyrene, tetra -chloro styrene, acrylonitrile, ethacrylonitrile, methacrylonitrile, alpha-chloroacrylonitrile, beta -chloroacrylonitrile, alpha-bromoacrylonitrile, methyl acrylate, methylmethacrylate, ethyl acrylate, n-butyl acrylate, n-butyl methacrylate, propyl acrylate, isopropyl acrylate, 2-ethylhexyl acrylate, or a combination comprising at least one of the foregoing monomers.

27. The composition of claim 1 , wherein the impact modifier comprises an acrylic impact modifier, an ASA impact modifier, a diene impact modifier, an organosiloxane impact modifier, an organosiloxane-branched acrylate impact modifier, an EPDM impact modifier, a styrene-butadiene-styrene impact modifier, a styrene-ethylene-butadiene-styrene impact modifier, an ABS impact modifier, an MBS impact modifier, a glycidyl ester impact modifier, or a combination comprising at least one of the foregoing impact modifiers.

28. An article comprising the composition of claim 1 and having a wall having a thickness of 3 mm or less.

29. A method for forming an article, comprising molding, extruding or shaping the composition of claim 1 to form the article having a wall having a thickness of 3 mm or less.

30. The method of claim 29 further comprising ultrasonically welding the article to a polymeric part.

31. A method for making an article comprising ultrasonically welding a first part comprising a composition according to claim 1 to a second part.

32. The method of claim 31 wherein the second part comprises a composition according to claim 1 .

33. An article comprising a first part comprising a composition according to claim 1 ultrasonically welded to a second part.

34. The article of claim 33 wherein the second part comprises a composition according to claim 1 .