Hybrid Metallocene Catalyst and Method for Preparing Polyethylene Using the Same

Patent metadata

Field	Value
Publication number	US-2025136728-A1
Application number	US-202318836099-A
Country	US
Kind code	A1
Filing date	Nov 13, 2023
Priority date	Dec 15, 2022
Publication date	May 1, 2025
Grant date	—

Abstract

Provided are a hybrid metallocene catalyst comprising a first transition metal compound represented by Formula 1; and a second transition metal compound represented by Formula 2, which is useful in the preparation of a polyethylene having excellent impact strength and haze properties, and a method of preparing the polyethylene using the same:wherein Formulas 1 and 2 are described herein.

First claim

1 . A hybrid metallocene catalyst comprising
a first transition metal compound represented by Formula 1; and a second transition metal compound represented by Formula 2:

in Formula 1,
M 1 is a Group 4 transition metal,
A 1 is C, Si, or Ge,
R 11 to R 14 are each independently hydrogen, C 1-20 alkyl, C 2-20 alkenyl, C 1-20 alkoxy, C 6-20 aryl, C 7-20 alkylaryl, or C 7-20 arylalkyl,
one of R 15 and R 16 is C 2-20 alkoxyalkyl, and the other is C 1-20 alkyl, C 6-20 aryl, C 7-20 alkylaryl, or C 7-20 arylalkyl,
R is C 1-20 alkyl, and
X 11 and X 12 are each independently halogen or C 1-20 alkyl,

in Formula 2,
M 2 is a Group 4 transition metal,
A 2 is C 2-20 alkylene,
R 21 , R 22 , R 21 ′ and R 22 ′ are each independently hydrogen, C 1-20 alkyl, C 1-20 alkoxy, C 2-20 alkenyl, C 6-20 aryl, C 7-20 alkylaryl, C 7-20 arylalkyl, or C 2 -20 alkoxyalkyl, or R 21 and R 22 , or R 21 ′ and R 22 ′ are linked to each other to form one or more aliphatic rings, aromatic rings, or hetero rings, each optionally substituted with C 1-20 alkyl,
R 23 and R 23 ′ are each independently hydrogen, C 1-20 alkyl, or C 2-20 alkoxyalkyl, and
X 21 and X 22 are each independently halogen or C 1-20 alkyl.

2 . The hybrid metallocene catalyst of claim 1 , wherein in Formula 1,
M 1 is Ti, Zr, or Hf, A 1 is Si, R 11 to R 14 are each independently hydrogen or C 1-8 alkyl, one of R 15 and R 16 is C 2-12 alkoxyalkyl and the other is C 1-8 alkyl or C 6-12 aryl, R is C 1-8 alkyl, and X 11 and X 12 are each independently halogen or methyl.

3 . The hybrid metallocene catalyst of claim 1 , wherein in Formula 1,
M 1 is Ti or Zr, A 1 is Si, R 11 to R 14 are each independently hydrogen or methyl, one of R 15 and R 16 is t-butoxyethyl, t-butoxybutyl, or t-butoxyhexyl, and the other is methyl or phenyl, R is t-butyl, and X 11 and X 12 are each chloro.

4 . The hybrid metallocene catalyst of claim 1 , wherein the first transition metal compound is any one selected from the group consisting of the following compounds:

5 . The hybrid metallocene catalyst of claim 1 , wherein the second transition metal compound is represented by Formula 2-1 or 2-2:

in Formulae 2-1 and 2-2,
M 2 is Ti, Zr, or Hf,
A 2 is C 2-6 alkylene,
R 23 and R 23 ′ are each independently hydrogen, C 1-8 alkyl, or C 2 -12 alkoxyalkyl, and
X 21 and X 22 are each independently chloro or methyl.

6 . The hybrid metallocene catalyst of claim 5 , wherein M 2 is Zr,
A 2 is ethylene, propylene, or butylene, R 23 and R 23 ′ are each independently hydrogen, n-butyl, or t-butoxyhexyl, and X 21 and X 22 are each chloro.

7 . The hybrid metallocene catalyst of claim 1 , wherein the second transition metal compound is any one selected from the group consisting of the following compounds:

8 . The hybrid metallocene catalyst of claim 1 , wherein the first transition metal compound and the second transition metal compound are included at a molar ratio of 4:1 to 3:2.

9 . The hybrid metallocene catalyst of claim 1 , further comprising one or more of a cocatalyst or a support.

10 . The hybrid metallocene catalyst of claim 9 , wherein the cocatalyst includes a compound represented by Formula 3:
[Al(R 41 )—O] a -  [Formula 3]
in Formula 3, R 41 is halogen; or C 1-20 hydrocarbyl unsubstituted or substituted with halogen; and a is an integer of 2 or more.

11 . The hybrid metallocene catalyst of claim 9 , wherein the support includes silica, alumina, magnesia, or a mixture thereof.

12 . A method of preparing a polyethylene, the method comprising performing a slurry polymerization of an ethylene monomer and an olefin monomer while introducing hydrogen in the presence of the hybrid metallocene catalyst of claim 1 .

13 . The method of claim 12 , wherein the hydrogen is introduced in an amount of 5 ppm to 40 ppm, based on a total weight of monomers including the ethylene monomer and the olefin monomer, during the slurry polymerization.

14 . The method of claim 12 , wherein the olefin monomer is introduced in an amount of 10% by weight to 15% by weight, based on a total weight of monomers including the ethylene monomer and the olefin monomer.

15 . The method of claim 12 , wherein the olefin monomer is 1-hexene.

16 . The method of claim 12 , wherein the polyethylene satisfies the following:
(i) a density measured according to the ASTM D1505 standard: 0.915 g/cm 3 to 0.920 g/cm 3 (ii) a melt index (MI) measured under conditions of 190° C. and 2.16 kg according to the ASTM D1238 standard: 0.8 g/10 min to 1.2 g/10 min (iii) a broad orthogonal crystalline fraction (BOCF) index calculated according to Equation 1:1 or more
BOCF index={Sum of regions/188.5560176}+{1/297.9631479}  [Equation 1]

in Equation 1, the sum of regions is calculated through steps of obtaining a contour plot of contents of fractions according to an elution temperature (Te) and a weight average molecular weight (Log M) from CFC analysis of the polyethylene; deriving a coefficient map of the sum of regions by arbitrarily dividing the fractions according to the Te and Log M into a plurality of regions, and assigning an arbitrary coefficient to each of the regions according to a contribution of the fractions to a dart drop impact strength; obtaining an actual element value for each of the regions by substituting the coefficient map of the sum of regions into the contour plot and calculating an area of a signal for each of the regions; and calculating the sum of regions by multiplying the actual element value for each of the regions by a coefficient value assigned above for each of the regions to obtain the sum of regions.

17 . The method of claim 12 , wherein the polyethylene has a dart drop impact strength of 1800 gf or more, as measured according to the ASTM D 1709 [Method A], and a film haze of 13% or less, as measured according to the ISO 13468, after producing a polyethylene film (BUR of 2 to 3 and a film thickness of 45 μm to 55 μm) using a film applicator.

Assignees

• Lg Chemical Ltd

Inventors

• Kim Byung Seok
• Kang Minyoung
• Lee Sung Min
• Lee Jinyoung
• Gwon Donghyeon
• Jung Yoonchul
• Lee Chaeeun
• Kim Seyoung
• Han Chang Woan
• Kim Youngkook
• Kim Dong Hyun
• Lee Suhyeon

Classifications

• C08F2800/20

  as weight or mass percentages · CPC title

• C08F2420/10

  Heteroatom-substituted bridge, i.e. Cp or analog where the bridge linking the two Cps or analogs is substituted by at least one group that contains a heteroatom · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08F2420/07

  Heteroatom-substituted Cp, i.e. Cp or analog where at least one of the substituent of the Cp or analog ring is or contains a heteroatom · CPC title

• C08F2420/02

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