Very low density polyethylene produced with single site catalyst
Provided herein are VLDPE polymer compositions suitable for use in the manufacture of flexible films or sheets. In one embodiment, the copolymer comprises a polyethylene VLDPE resin with M z /M w of greater than 2, CDBI 50 of greater than 55 and a single melting peak in DSC measurement. The polymer compositions disclosed herein may be suitable for use in the manufacture of films with improved balance of film toughness, processability and sealability in monolayer and multi-layer film structures.
1. An ethylene copolymer having
a) a density from about 0.890 to about 0.915 g/cm 3 ,
b) a molecular weight distribution M w /M n from about 2.2 to about 4.5,
c) a molecular weight distribution M z /M w of greater than 2, provided that when the M z /M w is greater than 3, the copolymer further has a normal to flat comonomer distribution,
d) a CDBI 50 from about 55 to about 98, and
e) a single peak in a DSC measurement.
2. An ethylene copolymer having
a) a density from about 0.890 to about 0.915 g/cm 3 ,
b) a molecular weight distribution M w /M n from about 2.2 to about 4.5,
c) a molecular weight distribution M z /M w from about 2 to about 3,
d) a CDBI 50 from about 55 to about 98, and
e) a single peak in a DSC measurement.
3. An ethylene copolymer having
a) a density from about 0.890 to about 0.915 g/cm 3 ,
b) a molecular weight distribution M w /M n of from about 2.2 to about 4.5,
c) a molecular weight distribution M z /M w of greater than 3,
d) a normal to flat comonomer distribution,
e) a CDBI 50 from about 55 to about 98, and
f) a single peak in a DSC measurement.
4. The ethylene copolymer of claim 1 that additionally exhibits a reverse comonomer distribution.
5. The ethylene copolymer of claim 1 wherein the Melt Index, I 2 is from about 0.25 to about 20 g/10 min.
6. The ethylene copolymer of claim 1 wherein Melt Index, I 2 is from about 0.25 to about 10 g/10 min.
7. The ethylene copolymer of claim 1 wherein Melt Index, I 2 is from about 10 to about 20 g/10 min.
8. The ethylene copolymer of claim 1 wherein Melt Index, I 2 is from about 0.4 to about 10 g/10 min.
9. The ethylene copolymer of claim 1 wherein Melt Index, I 2 is from about 0.4 to about 2 g/10 min.
10. The ethylene copolymer of claim 1 wherein M w /M n is from about 2.6 to about 4.5.
11. The ethylene copolymer of claim 1 wherein M w /M n is from about 3.5 to about 4.3.
12. The ethylene copolymer of claim 1 wherein M w /M n is from about 2.6 to about 4.3.
13. The ethylene copolymer of claim 1 wherein M z /M w is from about 2.0 to about 2.5.
14. The ethylene copolymer of claim 1 wherein M z /M w is from about 2.5 to about 2.8.
15. The ethylene copolymer of claim 1 wherein M z /M w is from about 2.5 to about 3.
16. The ethylene copolymer of claim 1 wherein M z /M w is from about 2.1 to about 2.8.
17. The ethylene copolymer of claim 1 wherein M z /M w is from 3 to about 6.
18. The ethylene copolymer of claim 1 wherein M z /M w is from 3 to about 5.
19. The ethylene copolymer of claim 1 wherein M z /M w is from 3 to about 4.
20. The ethylene copolymer of claim 1 wherein M z /M w is from 3 to about 3.5.
21. The ethylene copolymer of claim 1 wherein the DSC measurement of the copolymer shows a single peak with a shoulder.
22. The ethylene copolymer of claim 1 wherein the GPC trace of the copolymer is bimodal.
23. The ethylene copolymer of claim 1 wherein the GPC trace of the copolymer is bimodal and the two peaks are separated by a valley.
24. The ethylene copolymer of claim 1 wherein the GPC trace of the copolymer is bimodal but the two peaks may not be easily deconvoluted.
25. The ethylene copolymer of claim 1 wherein the CDBI 50 is from about 65 to about 95.
26. The ethylene copolymer of claim 1 wherein the CDBI 50 is 70 to about 85.
27. The ethylene copolymer of claim 1 wherein the CDBI 50 is greater than 75 to about 98.
28. The ethylene copolymer of claim 1 wherein the CDBI 50 is 55 to about 70.
29. The ethylene copolymer of claim 1 wherein the CDBI 50 is 70 to about 98.
30. The ethylene copolymer of claim 1 wherein G′ at G″ (500 Pa) at 190° C. is less than 40 Pa.
31. The ethylene copolymer of claim 1 wherein G′ at G″ (500 Pa) at 190° C. is less than 35 Pa.
32. The ethylene copolymer of claim 1 wherein G′ at G″ (500 Pa) at 190° C. is less than 30 Pa.
33. The ethylene copolymer of claim 1 wherein G′ at G″ (500 Pa) at 190° C. is from about 20 Pa to about 40 Pa.
34. The ethylene copolymer of claim 1 wherein G′ at G″ (500 Pa) at 190° C. is from about 20 Pa to about 35 Pa.
35. The ethylene copolymer of claim 1 made from ethylene and one or more C 3-12 alpha olefin comonomers in a continuous polymerization process.
36. The ethylene copolymer of claim 35 , wherein the continuous solution polymerization process comprises at least two polymerization reactors.
37. The ethylene copolymer of claim 35 , made from ethylene and one or more C 3-12 alpha olefin comonomers in a polymerization process using at least one single site catalyst.
38. The ethylene copolymer of claim 37 wherein the single-site catalyst is selected from catalysts of the formula:
wherein M is a group 4 metal;
PI is a phosphinimine ligand;
L is a monoanionic ligand selected from the group consisting of a cyclopentadienyl-type ligand;
Y is an activatable ligand;
m is 1 or 2;
n is 0 or 1; and
p is an integer and the sum of m+n+p equals the valence state of M.
39. The ethylene copolymer of claim 35 wherein the continuous solution polymerization process comprises
a first stirred tank polymerization reactor having a mean reactor temperature of from about 100° C. to less than about 140° C., and,
a second stirred tank reactor having a mean temperature of at least about 20° C. greater than the mean reactor temperature of the first reactor.
40. The ethylene copolymer claim 39 wherein the first stirred tank polymerization reactor has a mean reactor temperature of from about 120° C. to less than about 138° C.
41. The ethylene copolymer claim 39 wherein the first stirred tank polymerization reactor has a mean reactor temperature of from about 130° C. to less than about 137° C.
42. The ethylene copolymer of claim 37 wherein the single site catalyst is in the first reactor.
43. A polymer composition comprising the ethylene copolymer of claim 1 .
44. A blend polymer composition comprising the ethylene copolymer of claim 1 blended with one or more of LDPE, LLDPE, HDPE, VLDPE, or ULDPE.
45. A monolayer film comprising polymer composition of claim 43 .
46. A multilayer film, containing at least one layer comprising the polymer composition of claim 43 .
47. A packaging article comprising the polymer composition of claim 43 .