Bimodal PE Resins with Improved Melt Strength

Patent metadata

Field	Value
Publication number	US-2018305529-A1
Application number	US-201715492354-A
Country	US
Kind code	A1
Filing date	Apr 20, 2017
Priority date	Apr 20, 2017
Publication date	Oct 25, 2018
Grant date	—

Abstract

A method comprising introducing a polymerization feed comprising an α-olefin, a diluent, and a diene to a polymerization system, under polymerization conditions, whereby a polymer product is produced, wherein the diene is present at a level in the range of from about 1 ppm to about 1000 ppm based on the diluent.

First claim

1 . A method comprising:
introducing a polymerization feed comprising an α-olefin, a diluent, and a diene to a first polymerization zone, a second polymerization zone, or both the first polymerization zone and the second polymerization zone of a polymerization system comprising the first and the second polymerization zones in series, wherein the diene is present at a level in the range of from about 1 ppm to about 1000 ppm based on an amount of the diluent, polymerizing, whereby a polymer product is produced, wherein the polymer product is a bimodal polyethylene resin, and wherein the bimodal polyethylene resin comprises a high molecular weight (HMW) component and a low molecular weight (LMW) component, wherein the HMW component, the LMW component or both comprise the diene; and adjusting the amount of the diene, the type of the diene, or both the amount and the type of the diene introduced into the first polymerization zone, the second polymerization zone, or both the first polymerization zone and the second polymerization zone to alter the melt strength, the impact strength, the crossover modulus, or a combination thereof of the polymer product.

2 . The method of claim 1 , wherein the diene is selected from dienes having a boiling point of less than or equal to about 110° C.

3 . The method of claim 1 , wherein the diene is selected from the group consisting of conjugated dienes, non-conjugated dienes, and combinations thereof.

4 . The method of claim 3 , wherein the diene is selected from the group consisting of C6-C15 straight chain hydrocarbon non-conjugated dienes, C6-C15 branched chain hydrocarbon non-conjugated dienes, C6-C15 cyclic hydrocarbon non-conjugated dienes, and combinations thereof.

5 . The method of claim 4 , wherein the non-conjugated diene is selected from the group consisting of straight chain acyclic dienes, including 1,5-heptadiene; 1,4-pentadiene; 1,6-heptadiene; 1,7-octadiene; 1,4-hexadiene; 1,9-decadiene; branched chain acyclic dienes, including 5-methyl-1,4-hexadiene, 2-methyl-1,5-hexadiene, 6-methyl-1,5-heptadiene, 7-methyl-1,6-octadiene, 3,7-dimethyl-1,6-octadiene, 3,7-dimethyl-1,7-octadiene, 5,7-dimethyl-1,7-octadiene, 1,9-decadiene, and mixed isomers of dihydromyrcene; single ring alicyclic dienes, including 1,4-cyclohexadiene, 1,5-cyclooctadiene and 1,5-cyclododecadiene; multi-ring alicyclic fused and bridged ring dienes, including dicyclopentadiene, tetrahydroindene, methyl tetrahydroindene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes, including 5-methylene-2-norbornene (MNB), 5-ethylidene-2-norbomene (ENB), 5-vinyl-2-norbomene, 5-propenyl-2-norbornene, 5-isopropylidene-2-norbomene, 5-(4-cyclopentenyl)-2-norbomene and 5-cyclohexylidene-2-norbornene; and combinations thereof.

6 . The method of claim 3 , wherein the diene is a conjugated diene selected from the group consisting of 1,3-hexadiene, 2,4-hexadiene, 1,3-pentadiene, 1,3-butadiene, 2-methyl-1,3-butadiene, 4-methyl-1,3-pentadiene, 1,3-cyclopentadiene, and combinations thereof.

7 . The method of claim 1 , wherein the polymer product exhibits a λ, which is the number of long chain branches (LCB) per million carbon atoms, that is greater than that of a polymer product produced via the same method but absent the presence of the diene.

8 . The method of claim 7 , wherein the polymer product exhibits a λ greater than or equal to about 15 LCB/10 6 carbons.

9 . The method of claim 1 , wherein the polymer product exhibits an LCB content, as determined by α, which is the fraction of the total carbons that are long chain vertexes determined according to the equation:

α
=

υ
3

M
W

/

M
0

where
υ 3 =number of long branch vertexes,
M W =weight average molecular weight (g/mol), and
M 0 =molecular weight of repeating unit (Da),
that is greater than that of a polymer product produced via the same method but absent the presence of the diene.

10 . The method of claim 1 , wherein the polymerization system comprises one or more reactors selected from the group consisting of loop slurry reactors, fluidized bed gas phase reactors, multi-zone reactors, batch reactors, and CSTR reactors.

11 . The method of claim 1 , wherein the first and second polymerization zones in series comprise dual loop slurry reactors in series.

12 . (canceled)

13 . The method of claim 1 ,
wherein the LMW component has a weight average molecular weight (M w ) ranging from about 350 g/mol to about 75,000 g/mol; and wherein the HMW component has a M w ranging from about 50,000 g/mol to about 1,000,000 g/mol.

14 . The method of claim 1 , wherein the polymerization is carried out in the presence of a polymerization catalyst selected from the group consisting of chromium catalysts, Ziegler-Natta catalysts, metallocene catalysts, and combinations thereof.

15 . A method comprising:
enhancing the long chain branching (LCB) of a bimodal polyethylene (PE) polymer comprising a high molecular weight (HMW) component and a low molecular weight (LMW) component produced in a serial dual loop slurry reactor process by introducing a diene into a polymerization zone in which the HMW component is produced, into a polymerization zone in which the LMW component is produced, or into both the polymerization zone in which the HMW component is produced and the polymerization zone in which the LMW component is produced, and adjusting the amount of the diene, the type of the diene, or both the amount and the type of the diene introduced into the polymerization zone in which the HMW component is produced, the polymerization zone in which the LMW component is produced, or both the polymerization zone in which the HMW component is produced and the polymerization zone in which the LMW component is produced to alter the melt strength, the impact strength, the crossover modulus, or a combination thereof of the bimodal PE polymer.

16 . The method of claim 15 , wherein the diene is introduced at a level in the range of from about 1 ppm to about 1000 ppm based on a diluent.

17 . The method of claim 15 , wherein the diene is selected from the group consisting of dienes having a boiling point of less than or equal to about 110° C.

18 . The method of claim 15 , wherein the diene is selected from the group consisting of conjugated dienes, non-conjugated dienes, and combinations thereof.

19 . The method of claim 15 , wherein the diene is selected from the group consisting of 1,5-hexadiene; 1,3-butadiene; isoprene; 1,4-pentadiene; 1,6-heptadiene; 1,7-octadiene; 1,4-hexadiene; 1,9-decadiene; and combinations thereof.

20 . The method of claim 15 , wherein the polymer is a bimodal polyethylene (PE) copolymer.

21 . (canceled)

22 . (canceled)

23 . The method of claim 15 , wherein at least one of the dual loop slurry reactors comprises a Ziegler-Natta catalyst.

24 . A method comprising:
enhancing the long chain branching (LCB) of a bimodal polyethylene (PE) polymer comprising a high molecular weight (HMW) compone

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Beaulieu William B
• Ding Errun

Classifications

• C08L23/083 Primary

  with aliphatic polyenes, i.e. containing two or more carbon-to-carbon double bonds · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L2314/06

  Metallocene or single site catalysts · CPC title

• C08L2207/066

  LDPE (radical process) · CPC title

• C08L2207/068

  Ultra high molecular weight polyethylene · CPC title