Polycarbonate compositions having antistatic enhancers, method of preparing, and articles comprising the same
View Patent ↗A thermoplastic composition comprising a polycarbonate, a perfluoroalkyl sulfonate phosphonium salt, and a non-phosphonium perfluoroalkyl sulfonate salt is disclosed, wherein a molded flat disk prepared from the thermoplastic composition has a surface resistivity of 1.0×10 10 to 1.0×10 14 ohms measured at a temperature of 23±2° C. and at 50±1% relative humidity. A method of making the thermoplastic composition, and articles prepared therefrom, are also disclosed.
1. A thermoplastic composition comprising
a polycarbonate,
0.3 to 1.0 parts by weight, per 100 parts of the polycarbonate, of a perfluoroalkyl sulfonate phosphonium salt according to the formula:
wherein n is an integer of 0 to 3 and each R is independently a C 1-22 alkyl group, or three of the R groups are the same R group selected from the C 1-8 alkyl group and the fourth R group is different from the first three R groups and is a C 7-22 aralkyl group or a C 1-22 alkyl group, and
0.03 to 0.16 parts by weight, per 100 parts by weight of the polycarbonate, of a non-phosphonium perfluoroalkyl sulfonate salt according to the formula:
wherein n is an integer of 0 to 3 and Z + is a non-phosphonium cation,
wherein a molded flat disk prepared from the thermoplastic composition has a surface resistivity that is at least 20% lower than the surface resistivity of a molded flat disk prepared from a thermoplastic composition consisting essentially of the polycarbonate and perfluoroalkyl sulfonate phosphonium salt but without the non-phosphonium perfluoroalkyl sulfonate salt.
2. The thermoplastic composition of claim 1 , wherein the non-phosphonium perfluoroalkyl sulfonate anion is trifluoromethyl sulfonate, perfluoroethyl sulfonate, perfluoro-n-propyl sulfonate, perfluoro-2-propyl sulfonate, perfluoro-n-butyl sulfonate, perfluoro-2-butyl sulfonate, perfluoroisobutyl sulfonate, perfluoro-t-butyl sulfonate, or a combination comprising at least one of the foregoing perfluoroalkyl sulfonate anions.
3. The thermoplastic composition of claim 1 , wherein the perfluoroalkyl sulfonate phosphonium salt is present in the thermoplastic composition in an amount from 0.6 to 1.0 parts by weight, based on 100 parts by weight of the polycarbonate.
4. The thermoplastic composition of claim 1 , wherein the polycarbonate comprises bisphenol A carbonate units.
5. The thermoplastic composition of claim 1 , further comprising an additive including impact modifier, filler, colorant, antioxidant, heat stabilizer, light stabilizer, ultraviolet light absorber, plasticizer, lubricant, mold release agent, flame retardant, anti-drip agent, radiation stabilizer, or a combination comprising at least one of the foregoing additives, where the additive is present in amount that does not significantly adversely affect the desired properties of the thermoplastic composition.
6. The thermoplastic composition of claim 1 , wherein an article molded from the thermoplastic composition and having a thickness of 3.18 millimeters has a haze of 0.01 to 1.0%, according to ASTM D1003-00.
7. The thermoplastic composition of claim 1 , wherein an article molded from the thermoplastic composition and having a thickness of 3.18 millimeters has a percent transmission of greater than or equal to 85%, according to ASTM D1003-00.
8. The thermoplastic composition of claim 1 , wherein an article molded from the thermoplastic composition and having a thickness of 3.18 millimeters has a yellowness index (YI) of 0.1 to 3, according to ASTM D1925-70.
9. The thermoplastic composition of claim 1 , wherein a molded flat disk prepared from the thermoplastic composition has a static decay time for positive charge of 0.1 to 6 seconds, and a static decay time for negative charge of 0.1 to 7 seconds.
10. The thermoplastic composition of claim 1 , wherein the non-phosphonium perfluoroalkyl sulfonate salt is present in an amount of 0.08 to 0.16 parts by weight per 100 parts by weight of polycarbonate.
11. A thermoplastic composition according to claim 1 wherein the perfluoroalkyl sulfonate phosphonium salt is according to the formula:
wherein n=3 and each R is independently a C 1-22 alkyl group, or three of the R groups are the same R group selected from the C 1-8 alkyl group and the fourth R group is different from the first three R groups and is a C 7-22 aralkyl group or a C 1-22 alkyl group.
12. The thermoplastic composition of claim 11 , wherein each R is independently a C 1-22 alkyl group.
13. The thermoplastic composition of claim 1 , wherein the perfluoroalkyl sulfonate phosphonium salt is present in an amount of 0.5 to 1.0 parts by weight per 100 parts by weight of the polycarbonate.
14. The thermoplastic composition of claim 13 , wherein the perfluoroalkyl sulfonate phosphonium salt is according to the formula:
wherein n=3 and each R is independently a C 1-22 alkyl group, or three of the R groups are the same R group selected from the C 1-8 alkyl group and the fourth R group is different from the first three R groups and is a C 7-22 aralkyl group or a C 1-22 alkyl group.
15. The thermoplastic composition of claim 14 , wherein each R is independently a C 1-22 alkyl group.
16. The thermoplastic composition of claim 1 , wherein the non-phosphonium perfluoroalkyl sulfonate salt comprises a cation comprising an alkali metal cation, an alkaline earth metal cation, a transition metal cation, an ammonium cation, a mono-, di-, tri- or tetra-C 1-22 alkylammonium cation, a pyridinium cation, or a combination comprising at least one of the foregoing cations.
17. The thermoplastic composition of claim 16 , wherein the cation is lithium, sodium, potassium, cesium, rubidium, ammonium, tetramethyl ammonium, trimethylbenzyl ammonium, tetraethylammonium, tetrabutylammonium, cetylammonium, pyridinium, or a combination comprising at least one of the foregoing cations.
18. The thermoplastic composition of claim 16 , wherein the non-phosphonium perfluoroalkyl sulfonate salt is potassium trifluoromethyl sulfonate, potassium perfluorobutyl sulfonate, or a combination comprising at least one of these.
19. The thermoplastic composition of claim 1 , wherein the perfluoroalkyl sulfonate phosphonium salt comprises a tetra(C 1-22 alkyl) phosphonium cation and perfluoroalkyl sulfonate anion.
20. The thermoplastic composition of claim 19 , wherein the tetra(C 1-22 alkyl) phosphonium cation is tetramethyl phosphonium, tetraethyl phosphonium, tetra-n-propyl phosphonium, tetraisopropyl phosphonium, tetrabutyl phosphonium, triethylmethyl phosphonium, tributylmethyl phosphonium, tributylethyl phosphonium, trioctylmethyl phosphonium, trimethylbutyl phosphonium, trimethyloctyl phosphonium, trimethyllauryl phosphonium, trimethylstearyl phosphonium, triethyloctyl phosphonium, trimethylbenzyl phosphonium, triethylbenzyl phosphonium, tributylbenzyl phosphonium, tetraphenyl phosphonium, triphenylmethyl phosphonium, and triphenylbenzyl phosphonium, or a combination comprising at least one of the foregoing cations.
21. The thermoplastic composition of claim 19 , wherein the perfluoroalkyl sulfonate phosphonium salt is tetrabutyl phosphonium perfluorobutyl sulfonate.
22. The thermoplastic composition of claim 1 , wherein the non-phosphonium perfluoroalkyl sulfonate salt is present in an amount of 0.03 to 0.08 parts by weight per 100 parts by weight of polycarbonate.
23. The thermoplastic composition of claim 22 , wherein the perfluoroalkyl sulfonate phosphonium salt is present in an amount of 0.5 to 1.0 parts by weight per 100 parts by weight of the polycarbonate.
24. The thermoplastic composition of claim 22 , wherein the non-phosphonium perfluoroalkyl sulfonate salt is present in the thermoplastic composition in an amount of from 0.6 to 1.0 parts by weight per 100 parts by weight of the polycarbonate.
25. The thermoplastic composition of claim 22 , wherein the perfluoroalkyl sulfonate phosphonium salt is according to the formula:
wherein n=3 and each R is independently a C 1-22 alkyl group, or three of the R groups are the same R group selected from the C 1-8 alkyl group and the fourth R group is different from the first three R groups and is a C 7-22 aralkyl group or a C 1-22 alkyl group.
26. The thermoplastic composition of claim 25 , wherein each R is independently a C 1-22 alkyl group.