Ethylene-based polymer composition
An ethylene-based polymer composition has been discovered and is characterized by a Comonomer Distribution Constant greater than about 45. The new ethylene-based polymer compositions are useful for making many articles, especially including films. The polymers are made using a metal complex of a polyvalent aryloxyether.
1. An ethylene-based polymer composition characterized by a bimodal or multimodal molecular weight distribution, a Comonomer Distribution Constant greater than about 45 and as high as 400, wherein the composition has less than 120 total unsaturation unit/1,000,000 C.
2. The polymer composition of claim 1 wherein the composition comprises up to about 3 long chain branches/1000 carbons.
3. The polymer composition of claim 1 having a zero shear viscosity ratio (ZSVR) of at least 2.
4. The polymer composition of claim 3 further characterized by comprising less than 20 vinylidene unsaturation unit/1,000,000 C.
5. A fabricated article comprising the composition of claim 1 .
6. The fabricated article of claim 5 in the form of at least one film layer.
7. The polymer composition of claim 1 further comprising a single DSC melting peak.
8. A thermoplastic formulation comprising the composition of claim 1 and at least one natural or synthetic polymer.
9. The formulation of claim 8 wherein a film comprising the formulation is characterized as having a yellowness b* change over 10 days of 3 or less.
10. The formulation of claim 9 wherein the ethylene-based composition comprises from about 60 to about 95 percent by weight of the formulation.
11. The composition of claim 1 , wherein said composition has been at least partially cross-linked (at least 5 wt % gel).
12. The composition of claim 1 wherein the composition has a comonomer distribution profile comprising a mono or bimodal distribution from 35° C. to 120° C., excluding purge.
13. The polymer composition of claim 1 further comprising Mw from about 17,000 to about 220,000 g/mol.
14. The ethylene-based polymer composition of claim 1 wherein a film comprising the composition is characterized as having a yellowness b* change over 10 days of 3 or less.
15. The ethylene-based polymer composition of claim 1 wherein a film comprising the composition is characterized as having a yellowness b* change over 10 days of 2 or less.
16. The ethylene-based polymer composition of claim 1 wherein a film comprising the composition is characterized as having a yellowness b* change over 10 days of 1 or less.
17. A polymerization process comprising:
(A) polymerizing ethylene and optionally one or more α-olefins in the presence of a first catalyst to form a semi-crystalline ethylene-based polymer in a first reactor or a first part of a multi-part reactor; and
(B) reacting freshly supplied ethylene and optionally one or more α-olefins in the presence of a second catalyst comprising an organometallic catalyst thereby forming an ethylene-based polymer composition in at least one other reactor or a later part of said multi-part reactor, wherein the catalyst of (A) and (B) can be the same or different and each is a metal complex of a polyvalent aryloxyether corresponding to the formula:
where M 3 is Ti, or Hf;
Ar 4 is independently in each occurrence a substituted C 9-20 aryl group, wherein the substituents, independently in each occurrence, are selected from the group consisting of alkyl; cycloalkyl; and aryl groups; and halo-, trihydrocarbylsilyl- and halohydrocarbyl-substituted derivatives thereof, with the proviso that at least one substituent lacks co-planarity with the aryl group to which it is attached;
T 4 is independently in each occurrence a C 2-20 alkylene, cycloalkylene or cycloalkenylene group, or an inertly substituted derivative thereof;
R 21 is independently in each occurrence hydrogen, halo, hydrocarbyl, trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl, alkoxy or di(hydrocarbyl)amino group of up to 50 atoms not counting hydrogen;
R 3 is independently in each occurrence hydrogen, halo, hydrocarbyl, trihydrocarbylsilyl, trihydrocarbylsilylhydrocarbyl, alkoxy or amino of up to 50 atoms not counting hydrogen, or two R 3 groups on the same arylene ring together or an R 3 and an R 21 group on the same or different arylene ring together form a divalent ligand group attached to the arylene group in two positions or join two different arylene rings together; and
R D is independently in each occurrence halo or a hydrocarbyl or trihydrocarbylsilyl group of up to 20 atoms not counting hydrogen, or 2 R D groups together are a hydrocarbylene, hydrocarbadiyl, diene, or poly(hydrocarbyl)silylene group.