Polymer compositions and processes for their production

• US 10,253,173 B2
• Filed: 12/28/2015
• Issued: 04/09/2019
• 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
• Primary Examiner(s): Harlan, Robert D.
• Application Number:
  US15/538,137
• Publication Number:
  US 20180002516A1
• Time in Patent Office: 1,198 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 polymerization processes and polymer compositions including reactor blends formed by such polymerization processes. The polymerization processes include copolymerization using two metallocene catalyst systems: the first catalyst system capable of producing polymers having 60% or more vinyl terminations, the second catalyst system capable of producing high molecular weight polymers, preferably incorporating at least some of the polymers produced by the first catalyst system into the high molecular weight polymers. The reactor blends formed thereby therefore include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw). Furthermore, the reactor blends may exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching. Preferred reactor blends comprise ethylene-propylene-diene (EPDM) terpolymers.

Claims

1. A polymer composition comprising a reactor blend of:

(a) a first 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 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 and having weight-average molecular weight of 50,000 g/mol or greater;

wherein the second copolymer component has weight-average molecular weight (Mw) greater than that of the first 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 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; and

(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;

(i) 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;

2. The polymer composition of claim 1, wherein the one or more C₂-C₁₂ α

-olefin monomers are one or both of propylene and butene, and further wherein the optional polyenes are selected from the group consisting of 5-ethylidene-2-norbornene (ENB), 5-vinyl-2-norbornene (VNB), 1,4,-hexadiene, dicyclopentadiene, and any combination thereof, such that each of the first and second copolymer components each independently comprise content derived from (i) ethylene;

(ii) propylene and/or butene, and, optionally; and

(iii) one or more of ENB, VNB, 1,4-hexadiene, and dicyclopentadiene.

3. The polymer composition of claim 2, wherein each of the first and second copolymer components is an EPDM terpolymer.

4. The polymer composition of claim 1, wherein the copolymerizing takes place in a plurality of polymerization zones comprising at least a first polymerization zone and a second polymerization zone.

5. The polymer composition of claim 4, wherein the polymerization process comprises:

copolymerizing at least a first portion of the plurality of monomers in the first polymerization zone in the presence of the VTP catalyst system to provide a polymerization intermediate comprising the VTP of the first copolymer component; and

copolymerizing (i) the polymerization intermediate and (ii) optionally, a second portion of the plurality of monomers, in the presence of the HMP catalyst system in the second polymerization zone, thereby obtaining the reactor blend.

6. The polymer composition of claim 1, wherein, within the VTP catalyst compound,

(1) each R³ is hydrogen;

(2) each R⁴ is independently a C₁-C₁₀ alkyl;

(3) each R² and R⁷ is independently hydrogen, or C₁-C₁₀ alkyl;

(4) each R⁵ and R⁶ is independently hydrogen, C₁-C₅₀ substituted or unsubstituted hydrocarbyl, or C₁-C₅₀ substituted or unsubstituted halocarbyl;

(5) R⁴ and R⁵, R⁵ and R⁶ and/or R⁶ and R⁷ may optionally be bonded together to form a ring structure; and

(6) J is a divalent bridging group represented by the formula R^a₂J′

, where J′

is Si, and each R^a is, independently, C₁ to C₂₀ substituted or unsubstituted hydrocarbyl, provided that the two R^a are bonded together to form a saturated or partially saturated cyclic or fused ring structure that incorporates J′

.

7. The polymer composition of claim 6, wherein the VTP catalyst compound comprises cyclotetramethylenesilylene-bis(2,4,7-trimethylinden-1-yl)hafnium dimethyl.

8. The polymer composition of claim 1, wherein the HMP catalyst compound is selected from mono-cyclopentadienyl amido group 4 transition metal complexes;

mono-Cp amido variants;

bridged fluorenyl-cyclopentadienyl group 4 transition metal complexes;

Cp-fluorenyl variants;

biphenyl phenol (BPP) transition metal complexes;

pyridyl amide transition metal complexes;

pyridyl diamide transition metal complexes; and

any combination thereof.

9. The polymer composition of claim 1, wherein the reactor blend comprises 30 wt % to 60 wt % of the first copolymer component, the balance comprising the second copolymer component.

10. The polymer composition of claim 1, wherein the 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.

11. The polymer composition of claim 1, 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.

12. The polymer composition of claim 11, having 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.

13. The polymer composition of claim 1, wherein the second copolymer component comprises one or more HMP copolymers incorporating a VTP (“

HMP-VTPs”

).

14. The polymer composition of claim 13, wherein the second copolymer component comprises either:

(i) comb-type polymers with amorphous backbones and semi-crystalline branches and (ii) comb-type polymers with semi-crystalline backbones and amorphous branches.

15. The polymer composition of claim 1, further comprising one or more curing agents, such that the first EPDM copolymer and second EPDM copolymer are at least partially cross-linked.