Polymer compositions and processes for their production

• US 10,538,656 B2
• Filed: 02/04/2019
• Issued: 01/21/2020
• 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:
  US16/266,186
• Publication Number:
  US 20190169413A1
• Time in Patent Office: 351 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 EPDM copolymer having ethylene-derived content in a range of 20 to 80 wt %, diene-derived content in a range of 0.3 to 15 wt %, Mw of 5,000 to 80,000 g/mol, and at least 60% vinyl terminations relative to the total number of end-group unsaturations in the first EPDM copolymer; and

(b) a second EPDM copolymer having at least 5 wt % less ethylene content than the first EPDM copolymer, diene-derived content in a range of 0.3 to 15 wt %, and Mw at least 1.5 times greater than the Mw of the first EPDM copolymer;

wherein the reactor blend has both (i) a phase angle δ

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

(ii) LCB index measured at 125°

C. of less than 5.

2. The polymer composition of claim 1, wherein the reactor blend is formed by a polymerization process comprising:

(I) copolymerizing ethylene, propylene, and diene monomers in the presence of a VTP catalyst system, thereby forming a first polymerization intermediate comprising the first EPDM copolymer; and

(II) copolymerizing the first polymerization intermediate, and optionally additional ethylene, propylene, and diene monomers in the presence of a 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;

3. 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.

4. The polymer composition of claim 2, wherein at least a portion of the second EPDM copolymer incorporates at least a portion of the first EPDM copolymer in the first polymerization intermediate.

5. The polymer composition of claim 1, wherein the second EPDM copolymer 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.

6. The polymer composition of claim 1, wherein the first EPDM copolymer has a Mooney viscosity (1+4 at 125°

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

C.) of 20 mu or more.

7. The polymer composition of claim 1, having MWD (Mw/Mn) of 3.5 or greater.

8. The polymer composition of claim 1, having:

(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=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) LCB index measured at 125°

C. of less than 5; and

(v) relaxation time τ

(determined at 125°

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

9. 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.

10. The polymer composition of claim 9, further comprising one or more of:

extender oil, processing oil;

carbon black, plasticizer, and antioxidant.