Ethylene/1-Hexene Copolymer Having Improved Long-Term Physical Property Stability and Processibility

Patent metadata

Field	Value
Publication number	US-2025059307-A1
Application number	US-202318726279-A
Country	US
Kind code	A1
Filing date	Mar 7, 2023
Priority date	Mar 10, 2022
Publication date	Feb 20, 2025
Grant date	—

Abstract

Provided is an ethylene/1-hexene copolymer satisfying the following conditions, having excellent long-term stability and processability as well as pipe resistance to internal pressure, and being useful for manufacturing high-pressure heating pipes, PE-RT pipes or large-diameter pipes,a molecular weight distribution (Mw/Mn) is 8 to 12,a broad orthogonal co-monomer distribution (BOCD) is 1 to 2,an integral value in the region where Log M is 6 or more in a gel permeation chromatography GPC curve graph having an x-axis of log M and a y-axis of dw/dlogM is 3.0% or more of the total integral value, anda tie molecule fraction is 6.0% or more.

First claim

1 . An ethylene/1-hexene copolymer satisfying the following conditions:
a molecular weight distribution (Mw/Mn) is 8 to 12, (a broad orthogonal co-monomer distribution) (BOCD) is 1 to 2, an integral value in a region where Log M is 6 or more in a gel permeation chromatography (GPC) curve graph having an x-axis of log M and a y-axis of dw/dlogM is 3.0% or more of a total integral value, wherein the log M is a a log value of a weight average molecular weight, and the dwt/dlog M is a molecular weight distribution, and a tie molecule fraction is 6.0% or more.

2 . The ethylene/1-hexene copolymer of claim 1 ,
wherein the molecular weight distribution (Mw/Mn) is 10 to 11.8.

3 . The ethylene/1-hexene copolymer of claim 1 ,
wherein the BOCD is 1.04 to 1.8.

4 . The ethylene/1-hexene copolymer of claim 1 ,
wherein the integral value in the region where Log M is 6 or more in a GPC curve graph having an x-axis of log M and a y-axis of dw/dlogM is 3.03% or more of the total integral value.

5 . The ethylene/1-hexene copolymer of claim 1 ,
wherein the tie molecule fraction is 6.05% or more.

6 . The ethylene/1-hexene copolymer of claim 1 ,
which has a density measured according to ASTM D 1505 is of 0.945 g/cm 3 to 0.955 g/cm 3 .

7 . The ethylene/1-hexene copolymer of claim 1 ,
which has a melt index (MI 2.16 ) measured at 190° C. under a load of 2.16 kg according to ASTM D 1238 0.05 g/10 min to 0.25 g/10 min.

8 . The ethylene/1-hexene copolymer of claim 1 ,
which has a high-load melt index (HLMI, MI 21.6 ) measured at 190° C. under a load of 21.6 kg according to ASTM D 1238 is of 10 g/10 min to 18 g/10 min.

9 . The ethylene/1-hexene copolymer of claim 1 ,
which has a melt flow rate ratio (MI 21.6 /MI 2.16 ) measured at 190° C. according to ASTM D 1238 is of 85 to 120.

10 . The ethylene/1-hexene copolymer of claim 1 ,
which has a characteristic stress measured according to ASTM D 638 is of 13 MPa to 14.5 MPa.

11 . The ethylene/1-hexene copolymer of claim 1 ,
which has a resistance to internal pressure measured according to ISO 9080 of 10 MPa to 12 MPa.

12 . The ethylene/1-hexene copolymer of claim 1 ,
which has a strain hardening modulus, which is a slope of a linear fitting value between a true strain 8 and 12 in a Hookean constitutive model curve after measuring a strain/stress curve under 80° C. and 20 mm/min in accordance with ISO 18488 to obtain a Neo-Hookean constitutive model curve having a x-axis of λ 2 −1/λ, and a y-axis of σ true of 23 MPa to 25 MPa.

13 . The ethylene/1-hexene copolymer of claim 1 ,
which has a notch pipe test (NPT) result according to ISO 13479 of 1500 to 4000 hours.

14 . The ethylene/1-hexene copolymer of claim 1 ,
wherein a 1-hexene content in the ethylene/1-hexene copolymer is 3.0 wt % to 7.0 wt % based on a total weight of the ethylene/1-hexene copolymer.

15 . A method for preparing the ethylene/1-hexene copolymer according to claim 1 , comprising copolymerizing ethylene and 1-hexene in a mono-modal polymerization process in the presence of a catalyst composition comprising a first metallocene compound represented by Chemical Formula 1 and a second metallocene compound represented by Chemical Formula 2 while introducing hydrogen gas,
wherein the first metallocene compound and the second metallocene compound are included in a molar ratio of 1:2 to 1:8:
(Cp 1 R a ) n (Cp 2 R b )M 1 Z 3-n 1   [Chemical Formula 1]

in Chemical Formula 1, M 1 is a Group 4 transition metal; each of Cp 1 and Cp 2 is independently cyclopentadienyl unsubstituted or substituted with C 1-20 hydrocarbon; R a and R b are the same as or different from each other, and are each independently hydrogen, C 1-20 alkyl, C 1-20 alkoxy, C 2-20 alkoxyalkyl, C 6-20 aryl, C 6-20 aryloxy, C 2-20 alkenyl, C 7-40 alkylaryl, C 7-40 arylalkyl, C 8-40 arylalkenyl, C 2-20 alkynyl, or substituted or unsubstituted C 2-20 heteroaryl containing at least one N, O or S, provided that at least one of R a or R b is not hydrogen; Z 1 are each independently halogen, C 1-20 alkyl, C 2-20 alkenyl, C 7-40 alkylaryl, C 7-40 arylalkyl, C 6-20 aryl, substituted or unsubstituted C 1-20 alkylidene, substituted or unsubstituted amino, C 2-20 alkylalkoxy, or C 7-40 arylalkoxy; and n is 1 or 0,

in Chemical Formula 2,
M 2 is a Group 4 transition metal;
A is carbon, silicon, or germanium;
X 1 and X 2 are the same as or different from each other, and are each independently halogen, or C 1-20 alkyl;
R 1 to R 4 are the same as or different from each other, and are each independently hydrogen, C 1-20 alkyl, C 2-20 alkenyl, C 6-20 aryl, C 7-20 alkylaryl, or C 7-20 arylalkyl, or two or more substituents adjacent to each other of R 1 to R 4 are connected with each other to form a substituted or unsubstituted aliphatic ring, a substituted or unsubstituted aromatic ring, or a substituted or unsubstituted heteroaromatic ring containing at least one N, O or S;
R 5 and R 6 are the same as or different from each other, and are each independently C 1-20 alkyl, C 2-20 alkenyl, C 6-30 aryl, or C 2-20 alkoxyalkyl; and
R 7 is C 1-20 alkyl, C 2-20 alkenyl, or C 6-30 aryl.

16 . The method of claim 15 ,
wherein the first metallocene compound is represented by any one of the following structural formulae:

17 . The method of claim 15 ,
wherein the second metallocene compound is represented by any one of the following structural formulae:

18 . The method of claim 15 ,
wherein the mono-modal polymerization process is performed in a single loop slurry reactor.

19 . The method of claim 15 ,
wherein the 1-hexene is included in an amount of 4.0 wt % to 6.0 wt % based on a total weight of the ethylene in the copolymerization process.

20 . A pipe comprising the ethylene/1-hexene copolymer of claim 1 .

Assignees

• Lg Chemical Ltd

Inventors

• Kim Joongsoo
• Sung Yutaek
• Sun Ka Ram
• Lee Jinyoung
• Lee Hyojoon
• Kim Yeonsoo
• Jeong So Dam
• Jeon Min Hong

Classifications

• C08F2800/20

  as weight or mass percentages · CPC title

• C08F2500/12

  Melt flow index or melt flow ratio · CPC title

• C08F2500/07

  High density, i.e. > 0.95 g/cm3 · CPC title

• C08F2500/31

  Impact strength or impact resistance, e.g. Izod, Charpy or notched · CPC title

• C08F2420/02

  Cp or analog bridged to a non-Cp X anionic donor · CPC title