Polycarbonate composition
View Patent ↗A composition includes at least one poly(aliphatic ester)-polycarbonate copolymer, a polysiloxane-polycarbonate copolymer, non-bonding glass fibers, and titanium dioxide. The composition exhibits excellent impact properties and an ultra-white color.
1. A composition comprising:
20 to 75 wt % of a first poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight of from about 30,000 to about 40,000 measured by GPC based on bisphenol A polycarbonate standards;
a second poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight that is less than the weight average molecular weight of the first poly(aliphatic ester)-polycarbonate copolymer, wherein a weight ratio of the second poly(aliphatic ester)-polycarbonate copolymer to the first poly(aliphatic ester)-polycarbonate copolymer is from about 1:4 to about 5:2;
5 to 25 wt % of a polysiloxane-polycarbonate copolymer;
5 to 35 wt % of non-bonding glass fibers; and
greater than 0 to 15 wt % of titanium dioxide;
wherein the composition exhibits a notched Izod impact strength measured according to ASTM D256 of at least 90 J/m; a ductility measured according to ASTM D256 of at least 20%; and a L* measured according to CIELAB of at least 90.
2. 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.
3. The composition of claim 1 , wherein an ester repeat unit of the first poly(aliphatic ester)-polycarbonate copolymer is derived from sebacic acid.
4. The composition of claim 1 , wherein the second poly(aliphatic ester)-polycarbonate copolymer has a weight average molecular weight of from about 15,000 to about 25,000 measured by GPC based on bisphenol A polycarbonate standards.
5. The composition of claim 1 , comprising from about 20 to about 40 wt % of the first poly(aliphatic ester)-polycarbonate copolymer.
6. The composition of claim 1 , comprising from about 15 to about 55 wt % of the second poly(aliphatic ester)-polycarbonate copolymer.
7. The composition of claim 1 , wherein the titanium dioxide is coated with an inorganic or organic coating.
8. The composition of claim 1 , wherein the titanium dioxide has an average particle size of from about 30 nm to about 500 nm.
9. The composition of claim 1 , wherein the composition exhibits a L* measured according to CIELAB of at least 95.
10. The composition of claim 1 , wherein the composition exhibits a gloss measured according to ASTM D2457 (at 60°) of at least 40.
11. The composition of claim 1 , wherein the composition exhibits a gloss measured according to ASTM D2457 (at 60°) of at least 80.
12. The composition of claim 1 , wherein the composition exhibits a melt flow rate measured according to ASTM D 1238 (300° C., 1.2 kg, 6 minutes) of at least 3 g/10 min; and a flexural modulus measured according to ISO 178 of at least 3000 MPa.
13. The composition of claim 1 , wherein the composition exhibits a notched Izod impact strength measured according to ASTM D256 of at least 150 J/m.
14. The composition of claim 1 , wherein the composition exhibits a notched Izod impact strength measured according to ASTM D256 of from at least 200 J/m to about 350 J/m.
15. The composition of claim 1 , wherein the composition exhibits a flexural modulus measured according to ISO 178 of from at least 3000 MPa to about 6000 MPa.
16. The composition of claim 1 , wherein the composition contains at least 10 wt % of titanium dioxide; exhibits a notched Izod impact strength measured according to ASTM D256 of at least 200 J/m; and exhibits a L* measured according to CIELAB of at least 95.
17. The composition of claim 1 , wherein the composition exhibits a ductility measured according to ASTM D256 of at least 80%.
18. The composition of claim 1 , wherein the composition contains from about 5 to about 15 wt % of titanium dioxide and exhibits a ductility measured according to ASTM D256 of at least 80%.
19. The composition of claim 1 , wherein the composition exhibits a ductility measured according to ASTM D256 of 100%.
20. The composition of claim 1 , wherein the composition exhibits a ductility measured according to ASTM D256 of 100%.
21. The composition of claim 20 , wherein the composition exhibits a gloss measured according to ASTM D2457 (at 60°) of at least 40.
22. The composition of claim 20 , wherein the composition exhibits a gloss measured according to ASTM D2457 (at 60°) of at least 80.
23. The composition of claim 1 , wherein the first poly(aliphatic ester)-polycarbonate copolymer contains from about 2 to about 13 mol % of aliphatic ester units.
24. The composition of claim 23 , wherein the first poly(aliphatic ester)-polycarbonate copolymer contains from about 87 to about 98 mol % of carbonate units derived from bisphenol-A.
25. The composition of claim 23 , wherein the aliphatic ester units are derived from sebacic acid.
26. The composition of claim 1 , wherein a siloxane block chain length of the polysiloxane-polycarbonate copolymer is from about 30 to about 100.
27. The composition of claim 1 , wherein a siloxane block chain length of the polysiloxane-polycarbonate copolymer is from about 35 to about 55.
28. The composition of claim 1 , wherein the polysiloxane-polycarbonate copolymer has a siloxane block content of from about 15 wt % to about 25 wt %.
29. The composition of claim 1 , wherein the polysiloxane-polycarbonate copolymer has a siloxane block content of from greater than 6 wt % to about 22 wt %.
30. The composition of claim 1 , wherein the composition comprises from about 0.5 wt % to about 6 wt % of siloxane originating from the polysiloxane-polycarbonate copolymer.
31. The composition of claim 1 , wherein the composition has a total softblock content of less than 3.5 wt %.
32. The composition of claim 1 , wherein the composition does not contain zinc sulfide or calcium carbonate.
33. The composition of claim 1 , wherein the composition does not contain milled fibers, bonding glass fibers, or flat glass fibers.
34. The composition of claim 1 , wherein the composition has an a* value measured according to CIELAB of from −1 to zero.
35. The composition of claim 1 , wherein the composition has a b* value measured according to CIELAB of from 1 to 3.
36. The composition of claim 1 , wherein the composition exhibits a notched Izod impact strength measured according to ASTM D256 of from 150 J/m to about 300 J/m.
37. An article made from the composition of claim 1 that has a wall with a thickness of at least 0.3 mm and less than 1 mm.
38. The article of claim 37 , wherein the article is a part of a cellphone, a MP3 player, a computer, a laptop, a camera, a video recorder, an electronic tablet, a hand receiver, a kitchen appliance, or an electrical housing.
39. A composition comprising, based on the total weight of the composition:
20 to 40 wt. % of a first poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight of from about 30,000 to about 40,000 measured by GPC based on bisphenol A polycarbonate standards;
15 to 55 wt % of a second poly(aliphatic ester)-polycarbonate copolymer having a weight average molecular weight of from 15,000 to 25,000 measured by GPC based on bisphenol A polycarbonate standards,
5 to 25 wt. % of a polysiloxane-polycarbonate copolymer;
5 to 35 wt. % of non-bonding glass fibers; and
greater than 0 to 15 wt. % of titanium dioxide;
wherein
the composition exhibits a notched Izod impact strength measured according to ASTM D256 of at least 90 J/m; a ductility measured according to ASTM D256 of at least 20% ; and a L* measured according to CIELAB of at least 90.
40. The composition of claim 39 , wherein the non-bonding glass fiber is present in an amount of 10 to 20 wt. % based on the total weight of the composition.