Polycarbonate composition and articles formed therefrom
View Patent ↗A composition includes at least one poly(aliphatic ester)-polycarbonate copolymer, a polysiloxane-polycarbonate copolymer, and an electromagnetic shielding agent (such as metal fibers). The composition exhibits excellent impact properties and electromagnetic shielding properties when formed into an article. Another composition includes at least one poly(aliphatic ester)-polycarbonate copolymer, a polysiloxane-polycarbonate copolymer, and carbon fibers. This composition has excellent impact properties when formed into an article.
1. A composition comprising:
a first poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight of from about 15,000 to about 40,000 Da;
a polysiloxane-polycarbonate copolymer; and
at least about 3 wt % of an electromagnetic shielding agent, wherein the electromagnetic shielding agent comprises at least one of metal fibers and metal-coated fibers;
wherein the composition exhibits
a notched Izod impact strength measured according to ASTM D256 of at least about 110 J/m; and
a gloss measured according to ASTM D2457 (at 20°) of at least about 90.
2. The composition of claim 1 , comprising from about 5 to about 20 wt % of the electromagnetic shielding agent.
3. The composition of claim 1 , wherein the electromagnetic shielding agent is metal fibers.
4. The composition of claim 1 , wherein the aliphatic ester is derived from an aliphatic dicarboxylic acid that has a total of from 8 to 12 carbon atoms.
5. The composition of claim 1 , comprising up to about 85 wt % of the first poly(aliphatic ester)-polycarbonate copolymer.
6. The composition of claim 5 , wherein the first poly(aliphatic ester)-polycarbonate copolymer contains from about 87 to about 98 mol % of carbonate units derived from bisphenol-A and the aliphatic ester units are derived from sebacic acid.
7. The composition of claim 1 , further comprising a second poly(aliphatic ester)-polycarbonate copolymer; wherein a weight average molecular weight of the second poly(aliphatic ester)-polycarbonate copolymer is greater than the weight average molecular weight of the first poly(aliphatic ester)-polycarbonate copolymer.
8. The composition of claim 7 , wherein the first poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 15,000 to about 25,000 Da, and the second poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 30,000 to about 40,000 Da.
9. The composition of claim 7 , comprising from about 10 to about 55 wt % of the first poly(aliphatic ester)-polycarbonate copolymer and from about 5 to about 40 wt % of the second poly(aliphatic ester)-polycarbonate copolymer.
10. The composition of claim 7 , wherein the first and the second poly(aliphatic ester)-polycarbonate copolymer contains from about 87 to about 98 mol % of carbonate units derived from bisphenol-A and the aliphatic ester units are derived from sebacic acid.
11. The composition of claim 1 , comprising up to about 70 wt % of the polysiloxane-polycarbonate copolymer.
12. The composition of claim 1 , wherein a siloxane block chain length of the polysiloxane-polycarbonate copolymer is from about 30 to about 100.
13. The composition of claim 1 , wherein the polysiloxane-polycarbonate copolymer has a siloxane block content of from about 15 wt % to about 25 wt %.
14. The composition of claim 1 , wherein the composition exhibits a flexural modulus measured according to ISO 178 of at least about 2000 MPa.
15. The composition of claim 1 , wherein the composition exhibits a notched Izod impact strength measured according to ASTM D 256 of at least about 140 J/m;
a gloss measured according to ASTM D2457 (at 20°) of at least about 92; and
a shielding effectiveness measured according to ASTM D4935 of at least about 30 decibels.
16. The composition of claim 1 , wherein the composition exhibits a gloss measured according to ASTM D2457 (at 60°) of at least about 98.
17. An article made from the composition of claim 1 .
18. The article of claim 17 , having a wall with a thickness of at least 0.3 mm and less than 0.8 mm, wherein the composition exhibits
a notched Izod impact strength measured according to ASTM D 256 of at least about 110 J/m; and
a gloss measured according to ASTM D2457 (at 20°) of at least about 90.
19. The article of claim 18 , wherein the article is a component of a cellphone, an MP3 player, a computer, a laptop, a camera, a video recorder, an electronic tablet, a pager, a hand receiver, a video game, a calculator, a wireless car entry device, an automotive part, a filter housing, a luggage cart, an office chair, a kitchen appliance, an electrical housing, an electrical connector, a lighting fixture, a light emitting diode, an electrical part, or a telecommunications part.
20. A composition comprising:
a first poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight of from about 15,000 to about 40,000 Da;
a polysiloxane-polycarbonate copolymer; and
about 5 wt % to about 20 wt % carbon fibers;
wherein the composition exhibits
a notched Izod impact strength measured according to ISO 180 (23° C., 3 mm) of at least about 9.5 kJ/m2; and
a multiaxial impact strength (MAI) measured according to ASTM D3763 (23° C.) of at least about 13 J.
21. The composition of claim 20 , comprising up to about 85 wt % of the first poly(aliphatic ester)-polycarbonate copolymer.
22. The composition of claim 21 , wherein the first poly(aliphatic ester)-polycarbonate copolymer contains from about 87 to about 98 mol % of carbonate units derived from bisphenol-A and aliphatic ester units derived from sebacic acid.
23. The composition of claim 20 , further comprising a second poly(aliphatic ester)-polycarbonate copolymer, wherein a weight average molecular weight of the second poly(aliphatic ester)-polycarbonate copolymer is greater than the weight average molecular weight of the first poly(aliphatic ester)-polycarbonate copolymer.
24. The composition of claim 23 , wherein the first poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 15,000 to about 25,000 Da, and the second poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 30,000 to about 40,000 Da.
25. The composition of claim 20 , comprising up to about 70 wt % of the polysiloxane-polycarbonate copolymer.
26. The composition of claim 20 , wherein a siloxane block chain length of the polysiloxane-polycarbonate copolymer is from about 30 to about 100.
27. The composition of claim 20 , wherein the composition has a siloxane block content of from about 0.5 to about 5 wt %.
28. The composition of claim 20 , wherein the composition exhibits
a notched Izod impact strength measured according to ISO 180 (23° C., 3 mm) of at least about 11 kJ/m2; and
a multiaxial impact strength (MAI) measured according to ASTM D3763 (23° C.) of at least about 14 J.
29. The composition of claim 20 , wherein the composition exhibits a flexural modulus of at least about 9000 MPa and a gloss measured according to ASTM D2457 (at 20°) of at least about 10.
30. An article made from the composition of claim 20 .
31. The article of claim 30 , wherein the article has a wall with a thickness of at least 0.3 mm and less than 0.8 mm.
32. The article of claim 31 , wherein the article is a part of a cellphone, an MP3 player, a computer, a laptop, a camera, a video recorder, an electronic tablet, a pager, a hand receiver, a video game, a calculator, a wireless car entry device, an automotive part, a filter housing, a luggage cart, an office chair, a kitchen appliance, an electrical housing, an electrical connector, a lighting fixture, a light emitting diode, an electrical part, or a telecommunications part.