Polymer Compositions with Improved Rheological Properties

• US 20180002517A1
• Filed: 12/28/2015
• Published: 01/04/2018
• Est. Priority Date: 01/14/2015
• Status: Active Grant

• Current Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Original Assignee: ExxonMobil Chemical Patents Inc. (Exxon Mobil Corporation)
• Inventors: Canich, Jo Ann M., Kolb, Rainer, Ravishankar, Periagaram S., Matsunaga, Phillip T., Jiang, Peijun, Shah, Rhutesh K., Dharmarajan, Narayanaswami
• Granted Patent: US 10,385,198 B2
• Time in Patent Office: Days
• CPC Class Codes: C08F 2/001 Multistage polymerisation processes characterised by a change in reactor conditions without deactivating the intermediate polymer C08F295/00, C08F297/00 take precedence
• CPC Class Codes: C08F 210/06 Propene
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 210/18 with non-conjugated dienes, e.g. EPT rubbers
• CPC Class Codes: C08F 236/20 unconjugated
• CPC Class Codes: C08F 2500/04 Broad molecular weight distribution, i.e. Mw/Mn > 6
• CPC Class Codes: C08F 2500/09 Long chain branches
• CPC Class Codes: C08F 2500/17 Viscosity
• CPC Class Codes: C08F 4/65904 in combination with another component of C08F4/64
• CPC Class Codes: C08F 4/65908 in combination with an ionising compound other than alumoxane, e.g. (C6F5)4B-X+
• CPC Class Codes: C08F 4/65927 two cyclopentadienyl rings being mutually bridged
• CPC Class Codes: C08F 4/76 selected from titanium, zirconium, hafnium, vanadium, niobium or tantalum
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 2205/025 containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• CPC Class Codes: C08L 2205/06 having improved processability or containing aids for moulding methods
• CPC Class Codes: C08L 2207/07 Long chain branching
• CPC Class Codes: C08L 23/16 Elastomeric ethene-propene or ethene-propene-diene copolymers, e.g. EPR and EPDM rubbers
• CPC Class Codes: C08L 2312/04 with phenolic resin
• CPC Class Codes: C08L 2314/06 Metallocene or single site catalysts

Abstract

Provided herein are metallocene-catalyzed polymer compositions that exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching, as well as polymerization processes suitable for forming such polymer compositions. The polymer compositions may have both LCB index measured at 125° C. of less than 5; and phase angle δ at complex shear modulus G*=100,000 Pa of less than about 54.5°, as determined at 125° C. The polymer compositions of particular embodiments are reactor blends, preferably of ethylene copolymers (e.g., ethylene-propylene (EP) copolymers and/or ethylene-propylene-diene (EPDM) terpolymers). The reactor blend may include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw).

Claims

1. An olefinic polymer composition having both of the following properties:

LCB index measured at 125°

C. of less than 5; and

(ii) phase angle δ

at complex shear modulus G*=100,000 Pa of less than about 54.5°

, as determined at 125°

C.

2. The olefinic polymer composition of claim 1, further having one or both of the following properties:

(iii) corrected Mooney Large Relaxation Area (cMLRA) at Mooney Large Viscosity (ML)=80 Mooney Units (mu), such that cMLRA is from about 240 to about 2000 mu*sec, where ML is determined at (1+4@125°

C.); and

(iv) MLRA/ML ratio greater than R, where R is given as R=9.57(ML)−

40.83, where ML is the Mooney Large Viscosity of the polymer composition determined at (1+4@125°

C.).

3. The olefinic polymer composition of claim 1, further having one or more of the following properties:

(v) shear thinning index (STI) measured at 125°

C. greater than 0.950;

(vi) relaxation time T (determined at 125°

C. using the Cross equation) of greater than 1.4 sec; and

(vii) MWD greater than 4.

4. The olefinic polymer composition of claim 1, wherein the olefinic polymer composition comprises units derived from ethylene, units derived from a C₃-C₂₀ α

-olefin, and units derived from a non-conjugated diene.

5. The olefinic polymer composition of claim 4, wherein the polymer composition has from about 30 wt % to about 80 wt % units derived from ethylene, and from about 0.1 wt % to about 15 wt % units derived from 5-ethylidene-2-norbornene (ENB).

6. The olefinic polymer composition of claim 1, wherein the olefin polymer composition is a reactor blend of two or more ethylene copolymer components selected from the following:

a. a first ethylene copolymer component comprising units derived from ethylene, a C₃-C₂₀ α

-olefin, and optionally one or more dienes, the first copolymer having ethylene content in a range of about 20 wt % to about 80 wt %, based on the weight of the first copolymer; and

b. a second ethylene copolymer component comprising units derived from ethylene, a C₃-C₂₀ α

-olefin, and optionally one or more dienes, the second copolymer having ethylene content in a range of about 30 wt % to about 80 wt %, based on the weight of the second copolymer;

wherein the difference in ethylene content between the first and the second copolymer is at least 5 wt % and the ratio of Mw of the second copolymer to Mw of the first copolymer is 2 or greater.

7. The olefinic polymer composition of claim 6, wherein the first ethylene copolymer component comprises one or more vinyl-terminated polymers (VTPs) having greater than 60% vintyl terminations, and the second ethylene copolymer component comprises one or more high molecular weight polymers (HMPs) having Mw greater than 50,000.

8. The olefinic polymer composition of claim 7, wherein the one or more HMPs includes one or more HMP-VTPs having branch-block architecture.

9. The olefinic polymer composition of claim 7, wherein the one or more VTPs have a branching index g′

_vis of 0.98 or less.

10. The olefinic polymer composition of claim 6, wherein the reactor blend comprises 30 to 60 wt % of the first ethylene copolymer component, with the balance being the second ethylene copolymer component.

11. The olefinic polymer composition of claim 1, wherein the composition is a reactor blend of two or more copolymers selected from the following:

(i) a vinyl-terminated polymer (VTP) having greater than 60% vinyl terminations, the VTP comprising ethylene-derived units in an amount ranging from about 30 to about 80 wt %, diene-derived units in an amount ranging from about 0 to about 15 wt %, and the balance units derived from a C₃-C₂₀ α

-olefin, the wt % s based on the total weight of the VTP;

(ii) a high molecular weight polymer (HMP) having Mw greater than 50,000, the HMP comprising ethylene-derived units in an amount ranging from about 20 to about 80 wt %, diene-derived units in an amount ranging from about 0 to about 15 wt %, and the balance of units derived from a C₃-C₂₀ α

-olefin, the wt % s based on the total weight of the HMP; and

(iii) a HMP incorporating one or more VTPs (HMP-VTP), the HMP-VTP having;

(a) Mw greater than 100,000 g/mol;

(b) ethylene-derived units in an amount ranging from about 20 to about 80 wt %, diene-derived units in an amount ranging from about 0 to about 15 wt %, and the balance of units derived from a C₃-C₂₀ α

-olefin, the wt % s based on the total weight of the HMP; and

(c) a plurality of long chain branches.

12. The olefinic polymer composition of claim 11, wherein the reactor blend composition comprises (i) the VTP, (ii) the HMP, and the HMP-VTP.

13. The olefinic polymer composition of claim 11, wherein the HMP has at least 5 wt % lower ethylene content than the VTP.

14. The olefinic polymer composition of claim 11, wherein the olefinic polymer composition has Mooney viscosity (1+4 at 125°

C.) of 60 mu or more, and MLRA greater than 500 mu*sec, and further wherein first copolymer component has a Mooney viscosity (1+4 at 125°

C.) of 10 mu or less and the second copolymer component has a Mooney viscosity (1+4 at 125°

C.) of 20 mu or more.

15. The olefinic polymer composition of claim 1, wherein the olefinic polymer composition is made by a polymerization process comprising:

copolymerizing a plurality of monomers comprising (i) ethylene, (ii) one or more C₂-C₁₂ α

-olefin monomers, and optionally, (iii) one or more polyenes in the presence of a vinyl-terminated polymer-forming catalyst system (“

VTP catalyst system”

) and a high molecular weight polymer-forming catalyst system (“

HMP catalyst system”

), thereby forming the reactor blend;

wherein;

the HMP catalyst system comprises a HMP catalyst compound and a first activator;

(ii) the VTP catalyst system comprises a VTP catalyst compound and a second activator; and

(iii) the VTP catalyst compound has the structural formula;

16. The polymer composition of claim 15, wherein the VTP catalyst compound comprises cyclotetramethylenesilylene-bis(2,4,7-trimethylinden-1-yl)hafnium dimethyl.

17. The polymer composition of claim 15, wherein the HMP HMP catalyst compound is selected from mono-cyclopentadienyl amido group 4 metal complexes, bridged fluorenyl-cyclopentadienyl group 4 metal complexes, biphenyl phenol (BPP) transition metal complexes, pyridyl amide transition metal complexes, pyridyl diamide transition metal complexes, and any combination thereof.

18. A compounded copolymer composition comprising:

(a) the olefinic polymer composition of claim 1; and

(b) one or more additives.

19. The compounded copolymer composition of claim 18, wherein the one or more additives comprise a crosslinking agent.

20. The compounded copolymer composition of claim 19, wherein the crosslinking agent is a comprises one or both of a peroxide and a phenolic resin.

21. The compounded copolymer composition of claim 1, wherein the one or more additives comprise carbon black, a processing oil, and a crosslinking agent.

22. A polymer composition comprising a reactor blend of:

(a) a first ethylene copolymer component comprising a vinyl-terminated polymer (VTP) having at least 60% vinyl terminations relative to the total number of end-group unsaturations in the VTP, and further having 40 to 80 wt % content derived from ethylene, 0 to 15 wt % content derived from one or more polyenes, with the balance of content derived from one or more C₃-C₁₂ α

-olefins; and

(b) a second ethylene copolymer component comprising a high molecular weight polymer (HMP) having 35-75 wt % content derived from ethylene, 0 to 15 wt % content derived from one or more polyenes, with the balance of content derived from one or more C₃-C₁₂ α

-olefins;

wherein the second ethylene copolymer component has weight-average molecular weight (Mw) greater than that of the first ethylene copolymer component, and further has at least 5 wt % less ethylene-derived content than the ethylene-derived content of the first copolymer component; and

further wherein the reactor blend has one or more of the following properties;

(i) corrected Mooney Large Relaxation Area (cMLRA) at Mooney Large Viscosity (ML)=80 Mooney Units (mu), such that cMLRA is from 240 to 2000 mu*sec, where ML is determined at (1+4@125°

C.);

(ii) MLRA/ML ratio greater than R, where R is given as R=9.57(ML)−

40.83, where ML is the Mooney Large Viscosity of the copolymer composition determined at (1+4@125°

C.);

(iii) shear thinning index (STI) measured at 125°

C. greater than 0.950;

(iv) a phase angle δ

at complex shear modulus G*=100,000 Pa of less than 54.5°

;

(v) Mw/Mn greater than or equal to 3.5;

(vi) LCB index measured at 125°

C. of less than 5; and

(vii) relaxation time τ

(determined at 125°

C. using the Cross equation) of greater than 1.4 sec.

23. The polymer composition of claim 22, wherein the reactor blend has both (iv) a phase angle δ

at complex shear modulus G*=100,000 Pa of less than 54.5° and

(vi) LCB index measured at 125°

C. of less than 5.

24. The polymer composition of claim 22, wherein the reactor blend comprises 30 wt % to 60 wt % of the first copolymer component, the balance comprising the second copolymer component.

25. The polymer composition of claim 22, further comprising one or more curing agents, such that the first ethylene copolymer component and the second ethylene copolymer component are at least partially cross-linked.