Polymer compositions with improved rheological properties
First Claim
1. An olefinic polymer composition having both of the following properties:
- (i) long chain branching (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.
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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).
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Citations
25 Claims
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1. An olefinic polymer composition having both of the following properties:
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(i) long chain branching (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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A polymer composition comprising a reactor blend of:
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(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 ethylene 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) long chain branching (LCB) index measured at 125°
C. of less than 5; and(vii) relaxation time τ
(determined at 125°
C. using Cross equation) of greater than 1.4 sec. - View Dependent Claims (23, 24, 25)
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Specification