KR102651363B1 - Method for preparing polyolefin with advanced environmental stress crack resistance - Google Patents

Abstract

A method for manufacturing polyethylene is provided, which enables it to have excellent ESCR properties and mechanical strength as well as excellent formability when applied to polyethylene, especially heating pipes. In the present invention, polyethylene having excellent physical properties as described above can be provided by controlling the amount of compounds added in the polyethylene manufacturing process.

Description

Method for manufacturing polyethylene with excellent environmental stress crack resistance properties {METHOD FOR PREPARING POLYOLEFIN WITH ADVANCED ENVIRONMENTAL STRESS CRACK RESISTANCE}

The present invention relates to a method for producing polyethylene with excellent environmental stress crack resistance properties.

PERT (polyethylene raised temperature) refers to a material that maintains the advantages of existing polyethylene, such as weather resistance, formability, and hygiene, while greatly enhancing long-term durability at high temperatures and having a high lifespan of more than 50 years. It is mainly used as a heating pipe material, and has the characteristic of being able to withstand high temperature and high pressure conditions for a long time even if scratches occur during the pipe installation process.

In general, pipe cracking patterns are divided into ductile failure and brittle failure. In the case of ductile fracture, it occurs when a high level of stress is applied and progresses due to the destruction of the crystalline region of the sample, so the better the mechanical properties (yield strength), the higher the resistance. In the case of brittle fracture, it occurs when a low level of stress is continuously applied, and the crystal region of the sample remains the same, but cracks progress due to the destruction of the entanglement and tie-molecules that exist between crystals, resulting in environmental stress crack resistance. (ESCR, Environmental Stress Cracking Resistance) The better the characteristics, the higher the resistance.

In the case of high-density polyethylene, which has excellent mechanical properties, it is not easily deformed even under high temperature and high pressure conditions, but its environmental stress cracking resistance characteristics are weak and brittle fracture occurs when used for a long period of time. Low-density polyethylene has excellent environmental stress cracking resistance characteristics, but its mechanical properties are poor. There is a problem in that it is weak and easily deformed under high temperature and high pressure conditions.

Therefore, in the case of general PERT, two or more types of hybrid supported catalysts are used to optimize the product's molecular weight, density, molecular weight distribution, and SCB (short chain branch) content to find the optimal point of mechanical properties and environmental stress crack resistance. .

In addition, in order to mold the product into a pipe, it must have an appropriate level of flowability, so its physical properties are also considered an important factor.

Republic of Korea Publication No. 10-2017-0049272 Republic of Korea Publication No. 10-2010-0032556

Cheng, J. J., Polak, M. A., & Penlidis, A. (2011). Influence of micromolecular structure on environmental stress cracking resistance of high density polyethylene. Tunneling and Underground Space Technology, 26(4), 582-593.

The purpose of the present invention is to provide polyethylene that has excellent mechanical strength and environmental stress crack resistance characteristics so that it is not easily deformed for a long time under high temperature and high pressure conditions, has corresponding molecular weight, density and molecular weight distribution, and has excellent flow properties.

According to one embodiment of the present invention, continuously introducing an alkylaluminum compound, ethylene monomer, and hydrogen into a reactor; And a step of polymerizing ethylene monomer, wherein, with respect to 1 part by weight of ethylene monomer, the amount of alkylaluminum is 2.35×10 ^-4 to 2.60×10 ^-4 parts by weight/hr, and the amount of hydrogen is 0.55×10. A method for producing polyethylene from 10 ^-4 to 0.61×10 ^-4 parts by weight/hr is provided.

According to another embodiment of the present invention, ethylene monomer is used under a hybrid supported catalyst comprising at least one first transition metal compound represented by Formula 1 below and at least one second transition metal compound represented by Formula 2 below. Polyethylene produced by polymerization reaction is provided:

[Formula 1]

In Formula 1,

M ¹ is selected from the group consisting of elements of groups 3 to 10 on the periodic table,

X ¹ is a halogen group, amine group _, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C _{1 -C 20} ) alkylsiller C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,

n is an integer from 1 to 5,

Ar ¹ and Ar ² are the same as or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,

[Formula 2]

In Formula 2,

M ² is selected from the group consisting of elements of groups 3 to 10 on the periodic table,

X ² is a halogen group, amine group, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C ₁ -C ₂₀ ) alkylsiller, sillyl (C ₁ -C ₂₀ ) C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,

m is an integer from 1 to 5,

Ar ³ and Ar ⁴ are the same or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,

B is a component that connects the ligands Ar ³ and Ar ⁴ without directly coordinating with the transition metal M ² , and is a group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N), and phosphorus (P). Contains elements selected from,

L is hydrogen, (C ₁ -C ₂₀ )alkyl group, (C ₃ -C ₂₀ )cycloalkyl group, (C ₁ -C ₂₀ )alkylsilyl group, silyl (C ₁ -C ₂₀ )alkyl group, (C ₆ -C ₂₀ ) Aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )arylsilyl group, and Silyl (C ₆ -C ₂₀ ) selected from the group consisting of aryl groups,

p is 1 or 2.

According to the present invention, polyethylene with improved mechanical properties and environmental stress crack resistance characteristics is provided by controlling the amount of each compound added during polyethylene production.

In addition, by providing polyethylene with a high molecular weight and a wide molecular weight distribution, formability can be improved when manufacturing heating pipes.

Hereinafter, preferred embodiments of the present invention will be described. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

According to one embodiment of the present invention, continuously introducing an alkylaluminum compound, ethylene monomer, and hydrogen into a reactor; And a method for producing polyethylene is provided, including the step of polymerizing ethylene monomer.

The alkyl aluminum compound is used to remove moisture in the reactor. Specific examples of alkyl aluminum that can be used in the present invention include trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, diethylaluminum ethoxide, and tri-n-butyl. Examples include, but are not limited to, aluminum, diisobutyl aluminum hydride, triisobutyl aluminum, and diethylaluminum chloride. Preferably, triethylaluminum can be used.

The alkylaluminum is introduced into the reactor at a rate of 2.35×10 ^-4 to 2.60×10 ^-4 parts by weight/hr based on 1 part by weight of ethylene monomer per hour. If the input amount of the alkylaluminum is less than 2.35×10 ^-4 parts by weight/hr, the moisture present in the reactor is not smoothly removed, so polyethylene with a low molecular weight can be produced. On the other hand, if the input amount of the alkylaluminum exceeds 2.60×10 ^-4 parts by weight/hr, the alkylaluminum reacts with the catalyst, lowering the catalytic activity, and the polymerization reaction is terminated, thereby producing polyethylene with a low molecular weight.

Meanwhile, in the present invention, the amount of hydrogen input is preferably 0.55 × 10 ^-4 to 0.61 × 10 ^-4 parts by weight/hr based on 1 part by weight of ethylene monomer per hour. If the hydrogen input amount is less than 0.55×10 ^-4 parts by weight/hr, the molecular weight of the polymer is too high and there is a risk that flowability may be reduced, and if it exceeds 0.61×10 ^-4 parts by weight/hr, the polymerization reaction is terminated and the molecular weight is reduced. This is undesirable as low polyethylene can be produced.

In the present invention, the polymerization reaction of ethylene monomer proceeds in the presence of a catalyst, and the catalyst includes at least one first transition metal compound represented by the following formula (1) and at least one second transition metal compound represented by the following formula (2) It may be a hybrid supported catalyst containing.

[Formula 1]

In Formula 1,

M ¹ is selected from the group consisting of elements of groups 3 to 10 on the periodic table,

X ¹ is a halogen group, amine group _, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C _{1 -C 20} ) alkylsiller C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,

n is an integer from 1 to 5,

Ar ¹ and Ar ² are the same as or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,

[Formula 2]

In Formula 2,

M ² is selected from the group consisting of elements of groups 3 to 10 on the periodic table,

X ² is a halogen group, amine group, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C ₁ -C ₂₀ ) alkylsiller, sillyl (C ₁ -C ₂₀ ) C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,

m is an integer from 1 to 5,

Ar ³ and Ar ⁴ are the same or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,

B is a component that connects the ligands Ar ³ and Ar ⁴ without directly coordinating with the transition metal M ² , and is a group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N), and phosphorus (P). Contains elements selected from,

L is hydrogen, (C ₁ -C ₂₀ )alkyl group, (C ₃ -C ₂₀ )cycloalkyl group, (C ₁ -C ₂₀ )alkylsilyl group, silyl (C ₁ -C ₂₀ )alkyl group, (C ₆ -C ₂₀ ) Aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )arylsilyl group, and Silyl (C ₆ -C ₂₀ ) selected from the group consisting of aryl groups,

p is 1 or 2.

Specific examples of the first transition metal compound include bis(1-butyl-3-methylcyclopentadienyl)zirconium dichloride, bis(cyclopentadienyl)zirconium dichloride, bis(methylcyclopentadienyl)zirconium dichloride, Bis(tetramethylcyclopentadienyl)zirconium dichloride, bis(isopropylcyclopentadienyl)zirconium dichloride, bis(pentamethylcyclopentadienyl)zirconium dichloride, bis(n-butylcyclopentadienyl)zirconium dichloride, bis(t-butylcyclopentadienyl)zirconium dichloride, bis(cyclopentadienyl)titanium dichloride, bis(cyclopentadienyl)hafnium dichloride, etc., among these alone or in combination with 2 The above can be mixed and used, preferably bis(1-butyl-3-methylcyclopentadienyl)zirconium dichloride.

Specific examples of the second transition metal compound include rac-ethylenebis(tetrahydroindenyl)zirconium dichloride, diphenylmethylidene(n-butyl-cyclopentadienyl)(2,7-di-tert-butyl-9- Fluorenyl)zirconium dichloride, diphenylmethylidene (cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl)zirconium dichloride, ditolylmethylidene (cyclopentadienyl) ( 2,7-di-tert-butylfluoren-9-yl)zirconium dichloride, dimethylsilylene (2-methyl-4-(4'-tert-butylphenyl)indenyl) (tetramethylcyclopentadienyl) Zirconium dichloride, rac-ethylenebis(tetrahydroindenyl)zirconium dichloride, rac-ethylenebis(1-indenyl)zirconium dichloride, rac-ethylenebis(1-indenyl)hafnium dichloride, rac-ethylenebis (1-tetrahydroindenyl)zirconium dichloride, rac-ethylenebis(1-tetrahydroindenyl)hafnium dichloride, rac-dimethylsilanediylbis(2-methyl-tetrahydrobenzidenyl)zirconium dichloride, rac-dimethylsilanediylbis(2-methyl-tetrahydrobenzidenyl)hafnium dichloride, rac-diphenylsilanediylbis(2-methyl-tetrahydrobenzidenyl)zirconium dichloride, rac-diphenylsil Landiylbis(2-methyl-tetrahydrobenzidenyl)hafnium dichloride, rac-dimethylsilanediylbis(2-methyl-4,5-benzidenyl)zirconium dichloride, rac-dimethylsilanediylbis( 2-methyl-4,5-benzydenyl)hafnium dichloride, rac-diphenylsilanediylbis(2-methyl-4,5-benzydenyl)zirconium dichloride, rac-diphenylsilanediylbis( 2-methyl-4,5-benzydenyl)hafnium dichloride, rac-dimethylsilanediylbis(2-methyl-5,6-cyclopentadienylindenyl)zirconium dichloride, rac-dimethylsilanediylbis (2-methyl-5,6-cyclopentadienylindenyl)hafnium dichloride, rac-diphenylsilanediylbis(2-methyl-5,6-cyclopentadienylindenyl)zirconium dichloride, rac- Diphenylsilanediylbis(2-methyl-5,6-cyclopentadienylindenyl)hafnium dichloride, rac-dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, rac-dimethylsilyl Bis(2-methyl-4-phenylindenyl)hafnium dichloride, rac-diphenylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride, rac-diphenylsilylbis(2-methyl-4- Phenylindenyl)hafnium dichloride, iso-propylidene (cyclopentadienyl) (9-fluorenyl) zirconium dichloride, iso-propylidene (cyclopentadienyl) (9-fluorenyl) hafnium dichloride, Diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)hafnium dichloride, iso-propylidene(3-methyl Cyclopentadienyl)(9-fluorenyl)zirconium dichloride, iso-propylidene(3-methylcyclopentadienyl)(9-fluorenyl)hafnium dichloride, diphenylmethylidene(3-methylcyclopenta) Dienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylidene (3-methylcyclopentadienyl) (9-fluorenyl) hafnium dichloride, diphenylsilyl (cyclopentadienyl) (9- Fluorenyl)zirconium dichloride, diphenylsilyl (cyclopentadienyl) (9-fluorenyl)zirconium dichloride, diphenylmethylidene (cyclopentadienyl) (2,7-di-tert-butylfluorene -9-yl) Hafnium dichloride, diphenylmethylidene (3-tert-butylcyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) zirconium dichloride, diphenylmethylidene ( 3-tert-butylcyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (3-tert-butyl-5-methylcyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl)zirconium dichloride, diphenylmethylidene (3-tert-butyl-5-methylcyclopentadienyl) (2,7-di-tert-butyl Fluoren-9-yl)hafnium dichloride, 1,2-ethylenebis(9-fluorenyl)zirconium dichloride, 1,2-ethylenebis(9-fluorenyl)hafnium dichloride, rac-[1, 2-bis(9-fluorenyl)-1-phenyl-ethane]zirconium dichloride, rac-[1,2-bis(9-fluorenyl)-1-phenyl-ethane]hafnium dichloride, [1- (9-fluorenyl)-2-(5,6-cyclopenta-2-methyl-1-indenyl)ethane]zirconium dichloride, [1-(9-fluorenyl)-2-(5,6 -Cyclopenta-2-methyl-1-indenyl)ethane]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-phenyl-tetrahydropentarene]zirconium dichloride, [ 4-(fluorenyl)-4,6,6-trimethyl-2-phenyl-tetrahydropentarene]hafnium dichloride, iso-propylidene(2-phenyl-cyclopentadienyl)(9-fluorenyl) Zirconium dichloride, iso-propylidene (2-phenyl-cyclopentadienyl) (9-fluorenyl) Hafnium dichloride, diphenylmethylidene (2-phenyl-cyclopentadienyl) (9-fluorenyl) Zirconium dichloride, diphenylmethylidene (2-phenyl-cyclopentadienyl) (9-fluorenyl) hafnium dichloride, isopropylidene (2-phenyl-cyclopentadienyl) (2,7-di-tert -Butylfluoren-9-yl)zirconium dichloride, isopropylidene (2-phenyl-cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethyl Liden (2-phenyl-cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) zirconium dichloride, diphenylmethylidene (2-phenyl-cyclopentadienyl) (2,7 -di-tert-butylfluoren-9-yl)hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(p-tolyl)-tetrahydropentarene]zirconium dichloride , [4-(fluorenyl)-4,6,6-trimethyl-2-(p-tolyl)tetrahydropentarene]hafnium dichloride, [isopropylidene-(2-(p-tolyl)cyclopentadiene Nyl)-(9-fluorenyl)]zirconium dichloride, [isopropylidene-(2-(p-tolyl)cyclopentadienyl)-(9-fluorenyl)]hafnium dichloride, [4-( Fluorenyl)-4,6,6-trimethyl-2-(m-tolyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(m -Tolyl)tetrahydropentarene]hafnium dichloride, [isopropylidene(2-(m-tolyl)cyclopentadienyl)-(9-fluorenyl)]zirconium dichloride, [isopropylidene(2-( m-tolyl)cyclopentadienyl)-(9-fluorenyl)]hafnium dichloride, [diphenylmethylidene(2-(m-tolyl)cyclopentadienyl)-(9-fluorenyl)]zirconium Dichloride, [diphenylmethylidene(2-(m-tolyl)cyclopentadienyl)-(9-fluorenyl)]hafnium dichloride, [isopropylidene(2-(m-tolyl)cyclopentadienyl) )(2,7-di-tert-butylfluoren-9-yl)]zirconium dichloride, [isopropylidene(2-(m-tolyl)cyclopentadienyl)(2,7-di-tert-butyl fluoren-9-yl)]hafnium dichloride, [diphenylmethylidene(2-(m-tolyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)]zirconium dichloride Chloride, [diphenylmethylidene(2-(m-tolyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)]hafnium dichloride, [4-(fluorenyl) -4,6,6-trimethyl-2-(o-tolyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(o-tolyl)tetra Hydropentalene]hafnium dichloride, [isopropylidene(2-(o-tolyl)cyclopentadienyl)(9-fluorenyl)]zirconium dichloride, [isopropylidene(2-(o-tolyl)cyclo)] Pentadienyl)(9-fluorenyl)]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(2,3-dimethylphenyl)tetrahydropentarene]zirconium dichloride Chloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(2,3-dimethylphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6 ,6-trimethyl-2-(2,4-dimethylphenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(2,4-dimethylphenyl ) Tetrahydropentarene] zirconium dichloride, [isopropylidene (2- (2,3-dimethylphenyl) cyclopentadienyl) (9-fluorenyl)] zirconium dichloride, [isopropylidene (2- ( 2,3-dimethylphenyl)cyclopentadienyl)(9-fluorenyl)]hafnium dichloride, [isopropylidene(2-(2,4-dimethylphenyl)cyclopentadienyl)(9-fluorenyl) )]zirconium dichloride, [isopropylidene(2-(2,3-dimethylphenyl)cyclopentadienyl)(9-fluorenyl)]hafnium dichloride, [diphenylmethylidene(2-(2,3) -dimethylphenyl)cyclopentadienyl)(9-fluorenyl)]zirconium dichloride, [diphenylmethylidene(2-(2,3-dimethylphenyl)cyclopentadienyl)(9-fluorenyl)] Hafnium dichloride, [diphenylmethylidene(2-(2,4-dimethylphenyl)cyclopentadienyl)(9-fluorenyl)]zirconium dichloride, [diphenylmethylidene(2-(2,4- dimethylphenyl)cyclopentadienyl)(9-fluorenyl)]hafnium dichloride, [isopropylidene(2-(2,3-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butyl fluoren-9-yl)]zirconium dichloride, [isopropylidene(2-(2,3-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)] Hafnium dichloride, [isopropylidene(2-(2,4-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)]zirconium dichloride, [isopropylidene (2-(2,4-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)]hafnium dichloride, [diphenylmethylidene(2-(2,3 -dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)]zirconium dichloride, [diphenylmethylidene(2-(2,3-dimethylphenyl)cyclopentadiene Nyl)(2,7-di-tert-butylfluoren-9-yl)]hafnium dichloride, [diphenylmethylidene(2-(2,4-dimethylphenyl)cyclopentadienyl)(2,7- di-tert-butylfluoren-9-yl)]zirconium dichloride, [diphenylmethylidene(2-(2,4-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene -9-yl)]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(2,6-dimethylphenyl)tetrahydropentarene]zirconium dichloride, [4-( Fluorenyl)-4,6,6-trimethyl-2-(2,6-dimethylphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2 -(3,5-dimethylphenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(3,5-dimethylphenyl)tetrahydropentarene] Hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-tetramethylphenyl-tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6- trimethyl-2-tetramethylphenyl-tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(2,4-dimethoxyphenyl)tetrahydropentarene]zirconium Dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(2,4-dimethoxyphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4 ,6,6-trimethyl-2-(3,5-dimethoxyphenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(3,5 -dimethoxyphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(chlorophenyl)tetrahydropentarene]zirconium dichloride, [4-( Fluorenyl)-4,6,6-trimethyl-2-(chlorophenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(fluoro Phenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(fluorophenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorene) Nyl)-4,6,6-trimethyl-2-(difluorophenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(difluorine) Lophenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(pentafluorophenyl)tetrahydropentarene]zirconium dichloride, [4-( Fluorenyl)-4,6,6-trimethyl-2-(difluorophenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-( tert-butylphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(3,5-trifluoromethyl-phenyl)tetrahydropentarene] Zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(3,5-trifluoromethyl-phenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorine Nyl)-4,6,6-trimethyl-2-(3,5-di-tert-butylphenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl -2-(3,5-di-tert-butylphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(biphenyl)tetrahydropenta ren]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(biphenyl)tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6 ,6-trimethyl-2-naphthyl-tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-naphthyl-tetrahydropentarene]hafnium dichloride, [4-(fluorenyl)-4,6,6-trimethyl-2-(3,5-diphenyl-phenyl)tetrahydropentarene]zirconium dichloride, [4-(fluorenyl)-4,6 ,6-trimethyl-2-(3,5-diphenyl-phenyl)tetrahydropentarene]hafnium dichloride, isopropylidene (2-tetramethylphenyl-cyclopentadienyl)(9-fluorenyl)zirconium dichloride , Isopropylidene (2- (2,6-dimethylphenyl) cyclopentadienyl) (9-fluorenyl) zirconium dichloride, Isopropylidene (2- (3,5-dimethylphenyl) cyclopentadienyl) (9-Fluorenyl)zirconium dichloride, isopropylidene (2-(2,4-dimethoxyphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(3) , 5-dimethoxyphenyl) cyclopentadienyl) (9-fluorenyl) zirconium dichloride, isopropylidene (2- (2,3-dimethoxyphenyl) cyclopentadienyl) (9-fluorenyl) Zirconium dichloride, isopropylidene (2-(2,6-dimethoxyphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(chlorophenyl)cyclopentadienyl) (9-Fluorenyl)zirconium dichloride, isopropylidene (2-(dichlorophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(trichlorophenyl)cyclopenta Dienyl) (9-fluorenyl) zirconium dichloride, isopropylidene (2- (fluorophenyl) cyclopentadienyl) (9-fluorenyl) zirconium dichloride, isopropylidene (2- (difluoro Lophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(pentafluorophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(3,5-trifluoromethyl-phenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(tert-butylphenyl)cyclopentadienyl)(9 -Fluorenyl)zirconium dichloride, isopropylidene (2-(3,5-di-tert-butylphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-( Biphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, isopropylidene (2-(3,5-diphenyl-phenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride , Isopropylidene (2-naphthyl-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylidene (2-tetramethylphenyl-cyclopentadienyl) (9-fluorenyl) zirconium dichloride Chloride, diphenylmethylidene (2-(2,6-dimethylphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(3,5-dimethylphenyl)cyclopenta Dienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(2,4-dimethoxyphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(3,5-dimethoxyphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(2,3-dimethoxyphenyl)cyclopentadienyl)( 9-Fluorenyl)zirconium dichloride, diphenylmethylidene (2-(2,6-dimethoxyphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-( Chlorophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(dichlorophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(trichlorophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene(2-(fluorophenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride Chloride, diphenylmethylidene (2- (difluorophenyl) cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylidene (2- (pentafluorophenyl) cyclopentadienyl) ( 9-Fluorenyl)zirconium dichloride, diphenylmethylidene (2-(3,5-trifluoromethyl-phenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene ( 2-tert-butylphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(3,5-di-tert-butylphenyl)cyclopentadienyl)(9- Fluorenyl)zirconium dichloride, diphenylmethylidene (2-(biphenyl)cyclopentadienyl)(9-fluorenyl)zirconium dichloride, diphenylmethylidene (2-(3,5-diphenyl- Phenyl) cyclopentadienyl) (9-fluorenyl) zirconium dichloride, diphenylmethylidene (2-naphthyl-cyclopentadienyl) (9-fluorenyl) zirconium dichloride, isopropylidene (2- Tetramethylphenyl-cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(2,6-dimethylphenyl)cyclopentadienyl)(2 ,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(3,5-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene -9-yl)hafnium dichloride, isopropylidene (2-(2,4-dimethoxyphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, Isopropylidene (2-(3,5-dimethoxyphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(2, 3-dimethoxyphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(2,6-dimethoxyphenyl)cyclopentadiene Nyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene(2-(chlorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene -9-yl) Hafnium dichloride, isopropylidene (2-(dichlorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2 -(trichlorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(fluorophenyl)cyclopentadienyl)(2 ,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(difluorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene-9 -yl) Hafnium dichloride, isopropylidene (2-(pentafluorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2 -(3,5-trifluoromethyl-phenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(tert-butylphenyl) )Cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(3,5-di-tert-butylphenyl)cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, isopropylidene (2-(biphenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene-9 -yl) Hafnium dichloride, isopropylidene (2-(3,5-diphenyl-phenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, iso Propylidene (2-naphthyl-cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) hafnium dichloride, diphenylmethylidene (2-tetramethylphenyl-cyclopentadienyl) ( 2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(2,6-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butyl) Fluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(3,5-dimethylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium di Chloride, diphenylmethylidene (2-(2,4-dimethoxyphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2 -(3,5-dimethoxyphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(2,3-dimethoxy Phenyl) cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) hafnium dichloride, diphenylmethylidene (2- (2,6-dimethoxyphenyl) cyclopentadienyl) ( 2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(chlorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene-9 -yl) Hafnium dichloride, diphenylmethylidene (2-(dichlorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2 -(trichlorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene(2-(fluorophenyl)cyclopentadienyl)( 2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(difluorophenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene -9-yl) Hafnium dichloride, diphenylmethylidene (2-(pentafluorophenyl) cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) hafnium dichloride, diphenyl Methylidene (2-(3,5-trifluoromethyl-phenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2- (tert-butylphenyl)cyclopentadienyl)(2,7-di-tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(3,5-di-tert-butylphenyl ) Cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) hafnium dichloride, diphenylmethylidene (2- (biphenyl) cyclopentadienyl) (2,7-di- tert-butylfluoren-9-yl)hafnium dichloride, diphenylmethylidene (2-(3,5-diphenyl-phenyl)cyclopentadienyl)(2,7-di-tert-butylfluorene-9 -yl) hafnium dichloride, diphenylmethylidene (2-naphthyl-cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) hafnium dichloride, etc., among these. It can be used alone or in combination of two or more, and preferably rac-ethylenebis(tetrahydroindenyl)zirconium dichloride.

The molar ratio of the first transition metal compound and the second transition metal compound may be 1:1 to 50:1. If the molar ratio is less than 1:1, the moldability is poor due to poor flow, and if the molar ratio is less than 1:1, the moldability is poor. This is undesirable because the molecular weight is low and the ESCR properties deteriorate.

Cocatalyst compounds that can be used in the above embodiment include 1 or 2 or more selected from the group consisting of a compound containing a unit represented by Formula 3, a compound represented by Formula 4, and a compound represented by Formula 5. can be mentioned.

[Formula 3]

In Formula 3 above,

q is an integer greater than or equal to 2,

Al is aluminum,

O is oxygen,

Ra is halogen; or a (C ₁ -C ₂₀ ) hydrocarbyl group substituted or unsubstituted with halogen,

[Formula 4]

In Formula 4 above,

Q is aluminum or boron,

Rb are the same as or different from each other, and are each independently halogen; or a (C ₁ -C ₂₀ ) hydrocarbyl group substituted or unsubstituted with halogen,

[Formula 5]

In Formula 5 above,

[W] ⁺ is a cationic Lewis acid; or a cationic Lewis acid with a hydrogen atom bonded to it,

Z is a group 13 element,

Rc is the same or different from each other, and each independently (C ₆ -C ₂₀ )aryl substituted with one or two or more substituents selected from the group consisting of halogen, (C ₁ -C ₂₀ )hydrocarbyl group, alkoxy group, and phenoxy group. energy; It is a (C ₁ -C ₂₀ )alkyl group substituted with one or two or more substituents selected from the group consisting of halogen, (C ₁ -C ₂₀ )hydrocarbyl group, alkoxy group, and phenoxy group.

The cocatalyst compound is included in a catalyst composition together with the transition metal compound represented by Formula 1 or Formula 2 and serves to activate the transition metal compound. Specifically, in order for the transition metal compound to become an active catalyst component used in olefin polymerization, the ligand in the transition metal compound is extracted to cationize the central metal (M ¹ or M ² ) while generating a counter ion with a weak binding force, that is, an anion. A compound containing a unit represented by Formula 3, a compound represented by Formula 4, and a compound represented by Formula 5 that can act as a cocatalyst.

The 'unit' represented by Formula 3 is a structure in which q structures in [ ] are connected in the compound. If it includes the unit represented by Formula 3, other structures in the compound are not particularly limited, and the repeating unit of Formula 3 It may be a cluster-type, for example, spherical compound that is connected to each other.

The compound containing the unit represented by Formula 3 is not particularly limited, and alkylaluminoxane is preferable. Non-limiting examples include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc. Considering the activity of the transition metal compound, methylaluminoxane may be preferably used.

In addition, the compound represented by Formula 4 is not particularly limited as an alkyl metal compound, and non-limiting examples thereof include trimethyl aluminum, triethyl aluminum, triisobutyl aluminum, tripropyl aluminum, tributyl aluminum, dimethyl chloroaluminum, and triiso Propyl aluminum, tri-s-butyl aluminum, tricyclopentyl aluminum, tripentyl aluminum, triisopentyl aluminum, trihexyl aluminum, trioctyl aluminum, ethyldimethyl aluminum, methyldiethyl aluminum, triphenyl aluminum, tri-p-tolyl. These include aluminum, dimethyl aluminum methoxide, dimethyl aluminum ethoxide, trimethyl boron, triethyl boron, triisobutyl boron, tripropyl boron, and tributyl boron. Considering the activity of the transition metal compound, one or two or more types selected from the group consisting of trimethyl aluminum, triethyl aluminum, and triisobutyl aluminum may be preferably used.

Considering the activity of the transition metal compound, the compound represented by Formula 5 is a dimethylanilinium cation when [W] ⁺ is a cationic Lewis acid to which a hydrogen atom is bonded, and when [W] ⁺ is a cationic Lewis acid, [ (C ₆ H ₅ ) ₃ C] ⁺ , and [Z(Rc) ₄ ] ^- may be preferably used as [B(C ₆ F ₅ ) ₄ ] ^- .

The compound represented by Formula 5 is not particularly limited, but non-limiting examples where [W] ⁺ is a cationic Lewis acid to which a hydrogen atom is bonded include triethylammonium tetrakisphenyl borate, tributylammonium tetrakisphenyl borate, and trimethyl Ammonium tetrakisphenyl borate, tripropylammonium tetrakisphenyl borate, trimethylammonium tetrakis(p-tolyl)borate, tripropylammonium tetrakis(p-tolyl)borate, trimethylammonium tetrakis(o,p -Dimethylphenyl)borate, triethylammonium tetrakis(o,p-dimethylphenyl)borate, tributylammonium tetrakis(p-trifluoromethylphenyl)borate, trimethylammonium tetrakis(p-trifluoromethylphenyl) )borate, tributylammonium tetrakispentafluorophenylborate, anilinium tetrakisphenylborate, anilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate Phenyl)borate, N,N-diethylaniliniumtetrakispetylborate, N,N-diethylaniliniumtetrakisphenylborate, N,N-diethylaniliniumtetrakispentafluorophenylborate, di Ethylammonium tetrakispentafluorophenyl borate, triphenylphosphonium tetrakisphenyl borate, trimethylphosphonium tetrakisphenyl borate, triphenylcarbonium tetrakis(p-trifluoromethylphenyl)borate, triphenylcarbonium Tetrakispentafluorophenylborate, dimethylaniliniumtetrakis(pentafluorophenyl)borate, etc.

The cocatalyst compound may be included in a molar ratio of 10 to 200 based on the total content of the first transition metal compound represented by Formula 1 and the second transition metal compound represented by Formula 2. If the molar ratio of the cocatalyst is less than 10, the amount of the transition metal compound supported on the carrier is small, and if the molar ratio exceeds 200, the transition metal compound reacts with the cocatalyst present in the solvent layer, which is not desirable.

In the above embodiment, the carrier may be an organic or inorganic porous carrier such as silica, alumina, silica-alumina mixture, titanium oxide, or zeolite. The mixture of the first transition metal compound, the second transition metal compound, and the cocatalyst may exist in a solid powder state or a homogeneous solution state, and the mixture may be supported by a known method.

When preparing a hybrid supported catalyst, the reaction solvent is an aliphatic hydrocarbon solvent such as hexane or pentane, an aromatic hydrocarbon solvent such as toluene or benzene, a hydrocarbon solvent substituted with a chlorine atom such as thichloromethane, or an ether such as diethyl ether or tetrahydrofuran. Most organic solvents such as solvents, acetone, and ethyl acetate can be used, and toluene and hexane are preferably used, but are not limited thereto.

In the present invention, the polymerization reaction of polyethylene may be carried out in a gas phase, liquid phase, or slurry phase. Preferably, the polymerization reaction can be performed in a gas phase using a gas phase polymerization device. Additionally, each polymerization reaction condition may be modified in various ways depending on the polymerization method, desired polymerization result, or type of polymer.

Specifically, in the present invention, the polyethylene polymerization reaction is performed at a temperature range of 65 to 100°C, the injection amount of hexene introduced into the reactor is 0.05 to 0.15 kg/h, and the circulation rate of the mixed gas containing ethylene, hydrogen, and hexene is It may be 0.30 to 0.40 m/sec.

According to another embodiment of the present invention, ethylene monomer is used under a hybrid supported catalyst comprising at least one first transition metal compound represented by Formula 1 and at least one second transition metal compound represented by Formula 2. Polyethylene produced by polymerization reaction is provided. The polyethylene may have a number average molecular weight (Mn) of 10,000 to 50,000 g/mol, a weight average molecular weight (Mw) of 100,000 to 300,000 g/mol, and a Z average molecular weight (Mz) of 750,000 to 2,000,000 g/mol. . Additionally, the polyethylene may have a molecular weight distribution (MWD) of 4.5 to 10 and a molecular weight distribution (MZD) of 15 to 50.

Additionally, the polyethylene may have a melt flow index (MI _2.16 ) of 0.5 to 1 g/mol and a flow rate ratio (MFRR) of 50 to 80. Polyethylene has the above-mentioned number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), melt flow index (MI _2.16 ), and flow rate ratio (MFRR), resulting in environmental stress cracking resistance characteristics (hereinafter referred to as , also called ESCR) and mechanical strength are improved, and in particular, when manufacturing heating pipes, an appropriate level of flow is secured and formability is improved.

Additionally, the polyethylene of the present invention preferably has a density of 0.937 to 0.943 g/cm ³ . Density is a factor that greatly affects the physical properties and processing conditions of polyethylene, particularly affecting ESCR and mechanical strength. In general, the lower the density of polyethylene, the higher the ESCR but lower the mechanical strength, and the higher the density of polyethylene, the lower the ESCR and higher mechanical strength. In the present invention, the polyethylene resin has optimal ESCR and mechanical strength when the density is 0.937 to 0.943 g/cm ³ .

According to the polyethylene manufacturing method of the present invention, HS (Hardening stiffness) and LA (Lamellae area) are improved, and thus polyethylene with excellent ESCR is manufactured. Specifically, the polyethylene may have an HS of 104 kg/cm ³ or more and an LA of 12 m ² /mol or more. It is known that ESCR is related to the content of tie-molecules and entanglements present in the polymer resin, and can be predicted through the HS and LA of the polymer resin. In the case of polyethylene produced under the hybrid supported catalyst of the present invention, the measured ESCR acceleration value may be 1100 hours or more.

The ESCR acceleration measurement method is as follows. Prepare a sample cut to a certain size by making a polyethylene resin into a flat plate, and measure the tensile strength of the sample. The measured tensile strength is shown as a stress-strain curve, and the slope after strain hardening is measured from the stress-strain curve, which is called HS (Hardening stiffness).

Afterwards, a 0.5 mm deep notch was added to the surface of the polyethylene resin sample, the sample was bent uniformly, fastened to a channel, and immersed in a 50 vol% surfactant aqueous solution at 60°C to remove cracks in the sample. Measure time (t).

The above-described accelerated measurement method of ESCR can be applied without limitation to polyethylene with a weight average molecular weight (Mw) of 100,000 to 1,000,000, a molecular weight distribution (MWD) of 5.0 to 10.0, and a density of 0.935 to 0.950 g/ml.

The ESCR of conventionally commercialized polyethylene for high-temperature pipes is generally more than 8,760 hours, and since it takes more than a year to measure, there is a problem in that the ESCR of products developed during research and development cannot be measured immediately. However, according to the accelerated ESCR measurement method of the present invention, the ESCR evaluation time can be shortened by predicting the ESCR from the HS (Hardening stiffness) or LA (Lamellae Area) of the polymer resin.

Example

Hereinafter, embodiments of the present invention will be described in detail. The following examples are only for understanding of the present invention and do not limit the present invention.

Examples and Comparative Examples

(1) Preparation of hybrid supported catalyst

Bis(1-butyl-3-methylcyclopentadienyl)zirconium dichloride (S-PCI) was used as the first transition metal compound, and rac-ethylenebis(tetrahydroindenyl)zirconium was used as the second transition metal compound. Dichloride (STREM) was used.

All synthesis reactions were carried out in an inert atmosphere such as nitrogen or argon, and standard Schlenk and glove box techniques were used.

Toluene was used after additional drying by passing an anhydrous grade (Sigma-Aldrich) through an activated molecular sieve (4A) or an activated alumina layer. The cocatalyst, MAO (Methylaluminoxane), was purchased and used as a 10% toluene solution (HS-MAO-10%) (Albemarle), and the calcined silica was used without further treatment. Additionally, the catalyst compounds used in Examples and Comparative Examples were used without further purification.

To synthesize a hybrid supported catalyst, put silica (300g) in a 1L round bottom flask inside the glove box and take it out of the glove box, then add 1L toluene, slowly add MAO (1.7L) to the silica in slurry state, and let it sit at 70℃ for 1 hour. It was stirred for a while. The first transition metal compound (15 mmol) and the second transition metal compound (0.5 mmol) were placed in a round bottom flask, taken out of the glove box, dissolved in 100 ml of toluene, and then slowly added to the slurry in which silica and MAO reacted. After stirring at 50°C for 1 hour, the stirring was stopped, cooled to room temperature, the toluene supernatant was separated and removed, washed with toluene and n-hexane, and vacuum dried to obtain a supported catalyst in the form of a free-flowing powder.

(2) Polyethylene polymerization

In the examples and comparative examples, a vapor phase polymerization device was used, and common operating conditions for the vapor phase polymerization device are as follows. The polymerization temperature is 85 ^o C and the input rate of 1-hexene used as the copolymer is 0.11 kg/h. Triethylaluminum (TEAL) was used diluted to 10 wt% in hexane, and the circulation speed of the mixed gas was adjusted to 0.3~0.4 m/sec. The physical properties of other polymers were controlled by changing the input amounts of ethylene, hydrogen, and triethylaluminum, and the relative input amount (parts by weight) of hydrogen and triethylaluminum (TEAL) relative to the input amount of each compound (g/hr) and the amount of ethylene monomer. /hr) is shown in Table 1 below.

ethylene hydrogen Trialkyl Aluminum (TEAL) input
(g/hr) input
(g/hr) input
(10 ^-4 parts by weight/hr) input
(g/hr) input
(10 ^-4 parts by weight/hr) Example 1 20,000 1.2 0.60 4.9 2.45 Comparative Example 1 20,000 1.2 0.60 2.5 1.25 Comparative Example 2 18,500 1.2 0.65 4.9 2.65 Comparative Example 3 20,000 1.24 0.62 4.9 2.45 Comparative Example 4 21,000 1.26 0.60 4.9 2.33

The following physical properties were measured for the polyethylene manufactured in Example 1 and Comparative Examples 1 to 4 and the currently commercialized polyethylene product for high temperature pipes (PERT, polyethylene raised temperature), respectively, and are shown in Tables 2 and 3. The currently commercialized polyethylene product for high-temperature pipes was used as Comparative Example 5, and the physical properties of polyethylene were measured by the following method.

How to measure physical properties

(1) Melt flow index (MI _2.16 )

Measurement was made based on AMTM1238 at a measurement temperature of 190°C.

(2) Liquidity Ratio (MFRR)

MFR21.6 melt index (MI, 21.6kg load) was measured by dividing it by MFR2.16 (MI 2.16kg load).

(3) Density

Measurements were made based on ASTM D1505.

(4) Molecular weight (Mn, Mw, Mz), molecular weight distribution (MWD, MZD)

The results measured at 160°C were applied using a GPC system consisting of Polymer Laboratories Ltd (UK)'s PL GPC-220 and Differential Viscometer (M210R).

(5) Yield strength

It was measured at a speed of 50 mm/min based on ASTM D 638, and each specimen was measured four times and the average value was applied.

(6) HS (Hardening Stiffness)

It was measured at a speed of 50 mm/min based on ASTM D 638, and in the strain (mm)-stress (kgf/cm ² ) graph, at the strain hardening stage, which is the stage where the yield section ends and the stress increases at a constant slope, The slope was measured.

(7) LA (Lamellae Area)

LA is the melting point (T _m, ℃) measured by TA's DSC (Q-200), the melting enthalpy per unit volume of the polyethylene crystal (△h _m,crystal , 2.88*10 ⁸ J/m ³ ), and the basal surface of the polyethylene crystal. Using the surface free energy (σ _e , 60.9*10 ^-3 J/m ² ) and the equilibrium melting point (T _m ^o , 415K) of an infinite polyethylene crystal, the lamella thickness (LT) can be determined through equation (1) below. ), then the density of the specimen (d), weight average molecular weight (Mw), crystallinity of the specimen measured through DSC (DC, %), and volume per unit weight of polyethylene crystal (V _crystal , 1 m ³ /kg) The LA value was calculated using equation (2).

Equation (1)

Equation (2)

flowability Molecular Weight MI _2.16 MFRR
(MI _21.6 /MI _2.16 ) density
(g/ ^cm3 ) Mn
(g/mol) Mw
(g/mol) Mz
(g/mol) MWD MZD Example 1 0.64 62 0.9408 3.6 27 129 7.5 35 Comparative Example 1 0.72 53 0.9404 2.2 18 75 8.4 34 Comparative Example 2 0.45 59 0.9418 2.8 19 94 6.9 32 Comparative Example 3 0.61 54 0.9418 3.3 16 68 4.8 20 Comparative Example 4 0.57 55 0.9414 2.3 20 88 8.6 38 Comparative Example 5 0.6 35 0.9410 5.4 24 71 4.4 13

It can be seen that the polyethylene prepared in Example 1 has a similar density to commercialized PERT (Comparative Example 5), has a higher molecular weight, and has a higher polymer content than Comparative Examples 1 to 5. In Comparative Examples 1 and 4, a relatively small amount of triethylaluminum was input, so moisture removal from the reactor was not performed smoothly, and in Comparative Examples 2 and 3, the amount of hydrogen input was relatively increased compared to ethylene. Therefore, it can be confirmed that polyethylene with a low molecular weight was manufactured in Comparative Examples 1 to 4.

mechanical properties ESCR Forecast yield strength
(kgf/ ^cm2 ) HS
(kgf/ ^cm3 ) L.A.
(10 ⁹ m ² /mol) ESCR accelerated measurements
(hr) Example 1 175 104.4 14.3 1200 Comparative Example 1 164 99.6 8.9 720 Comparative Example 2 187 102.4 10.5 960 Comparative Example 3 188 97.8 8.6 672 Comparative Example 4 168 100.6 9.3 792 Comparative Example 5 166 103.6 11.6 1080

Table 3 shows the yield strength, HS, LA, and ESCR acceleration measurements of Example 1 and Comparative Examples 1 to 5. In the case of Example 1, it can be seen that while showing equal or superior flowability compared to Comparative Example 5, mechanical strength and environmental stress resistance characteristics are excellent.

Claims (11)

Continuously introducing an alkylaluminum compound, ethylene monomer, and hydrogen into the reactor; and
polymerizing ethylene monomer in the presence of a catalyst, or the catalyst and cocatalyst,
With respect to the ethylene monomer input amount of 1 part by weight per hour, the input amount of alkyl aluminum is 2.35 × 10 ^-4 to 2.60 × 10 ^-4 parts by weight / hr, and the input amount of hydrogen is 0.55 × 10 ^-4 to 0.61 × 10 ^-4 parts by weight. /hr polyethylene production method.
According to paragraph 1,
The alkyl aluminum compounds include triethyl aluminum, trimethyl aluminum, triethyl aluminum, tri-n-propyl aluminum, diethyl aluminum ethoxide, tri-n-butyl aluminum, diisobutyl aluminum hydride, triisobutyl aluminum and diethyl. A method for producing polyethylene, which is one or two or more compounds selected from the group consisting of aluminum chloride.
According to paragraph 1,
The catalyst is a hybrid supported catalyst comprising at least one first transition metal compound represented by the following formula (1) and at least one second transition metal compound represented by the following formula (2). Method for producing polyethylene:

[Formula 1]

In Formula 1,
M ¹ is selected from the group consisting of elements of groups 3 to 10 on the periodic table,
X ¹ is a halogen group, amine group _, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C _{1 -C 20} ) alkylsiller C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,
n is an integer from 1 to 5,
Ar ¹ and Ar ² are the same as or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,

[Formula 2]

In Formula 2,
M ² is selected from the group consisting of elements of groups 3 to 10 on the periodic table,
X ² is a halogen group, amine group, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C ₁ -C ₂₀ ) alkylsiller, sillyl (C ₁ -C ₂₀ ) C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,
m is an integer from 1 to 5,
Ar ³ and Ar ⁴ are the same or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,
B is a component that connects the ligands Ar ³ and Ar ⁴ without directly coordinating with the transition metal M ² , and is a group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N), and phosphorus (P). Contains elements selected from,
L is hydrogen, (C ₁ -C ₂₀ )alkyl group, (C ₃ -C ₂₀ )cycloalkyl group, (C ₁ -C ₂₀ )alkylsilyl group, silyl (C ₁ -C ₂₀ )alkyl group, (C ₆ -C ₂₀ ) Aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )arylsilyl group, and Silyl (C ₆ -C ₂₀ ) selected from the group consisting of aryl groups,
p is 1 or 2.
According to paragraph 3,
The first transition metal compound is bis(1-butyl-3-methylcyclopentadienyl)zirconium dichloride, and the second transition metal compound is rac-ethylenebis(tetrahydroindenyl)zirconium dichloride. .
According to paragraph 3,
A method for producing polyethylene, wherein the molar ratio of the first transition metal compound and the second transition metal compound is 1:1 to 50:1.
According to paragraph 3,
The cocatalyst compound is one or two or more compounds selected from the group consisting of a compound containing a unit represented by Formula 3, a compound represented by Formula 4, and a compound represented by Formula 5. Method for producing polyethylene:

[Formula 3]

In Formula 3 above,
q is an integer greater than or equal to 2,
Al is aluminum,
O is oxygen,
Ra is halogen; or a (C ₁ -C ₂₀ ) hydrocarbyl group substituted or unsubstituted with halogen,

[Formula 4]

In Formula 4 above,
Q is aluminum or boron,
Rb are the same as or different from each other, and are each independently halogen; or a (C ₁ -C ₂₀ ) hydrocarbyl group substituted or unsubstituted with halogen,

[Formula 5]

In Formula 5 above,
[W] ⁺ is a cationic Lewis acid; or a cationic Lewis acid with a hydrogen atom bonded to it,
Z is a group 13 element,
Rc is the same or different from each other, and each independently (C ₆ -C ₂₀ )aryl substituted with one or two or more substituents selected from the group consisting of halogen, (C ₁ -C ₂₀ )hydrocarbyl group, alkoxy group, and phenoxy group. energy; It is a (C ₁ -C ₂₀ )alkyl group substituted with one or two or more substituents selected from the group consisting of halogen, (C ₁ -C ₂₀ )hydrocarbyl group, alkoxy group, and phenoxy group.
According to clause 6,
A method for producing polyethylene, wherein the cocatalyst compound is included in a molar ratio of 10 to 200 based on the total content of the first transition metal compound represented by Formula 1 and the second transition metal compound represented by Formula 2.
A hybrid supported catalyst comprising at least one first transition metal compound represented by Formula 1 below and at least one second transition metal compound represented by Formula 2 below, or an alkyl catalyst in the presence of the hybrid supported catalyst and cocatalyst Polyethylene produced by polymerization of ethylene monomer added with an aluminum compound and hydrogen,
With respect to the ethylene monomer input amount of 1 part by weight per hour, the input amount of alkyl aluminum is 2.35 × 10 ^-4 to 2.60 × 10 ^-4 parts by weight / hr, and the input amount of hydrogen is 0.55 × 10 ^-4 to 0.61 × 10 ^-4 parts by weight. /hr, polyethylene:

[Formula 1]

In Formula 1,
M ¹ is selected from the group consisting of elements of groups 3 to 10 on the periodic table,
X ¹ is a halogen group, amine group _, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C _{1 -C 20} ) alkylsiller C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,
n is an integer from 1 to 5,
Ar ¹ and Ar ² are the same as or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,

[Formula 2]

In Formula 2,
M ² is selected from the group consisting of elements of groups 3 to 10 on the periodic table,
X ² is a halogen group, amine group, (C ₁ -C ₂₀ ) alkyl group, (C ₃ -C ₂₀ ) cycloalkyl group, (C ₁ -C ₂₀ ) alkylsiller, sillyl (C ₁ -C ₂₀ ) C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ ) Arylsilyl group, silyl (C ₆ -C ₂₀ )aryl group, (C ₁ -C ₂₀ )alkoxy group, (C ₁ -C ₂₀ )alkylsiloxy group and (C ₆ -C ₂₀ )aryloxy group. selected,
m is an integer from 1 to 5,
Ar ³ and Ar ⁴ are the same or different from each other and are each independently a ligand having a cyclopentadienyl skeleton,
B is a component that connects the ligands Ar ³ and Ar ⁴ without directly coordinating with the transition metal M ² , and is a group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N), and phosphorus (P). Contains elements selected from,
L is hydrogen, (C ₁ -C ₂₀ )alkyl group, (C ₃ -C ₂₀ )cycloalkyl group, (C ₁ -C ₂₀ )alkylsilyl group, silyl (C ₁ -C ₂₀ )alkyl group, (C ₆ -C ₂₀ ) Aryl group, (C ₆ -C ₂₀ )aryl(C ₁ -C ₂₀ )alkyl group, (C ₁ -C ₂₀ )alkyl(C ₆ -C ₂₀ )aryl group, (C ₆ -C ₂₀ )arylsilyl group, and Silyl (C ₆ -C ₂₀ ) selected from the group consisting of aryl groups,
p is 1 or 2.
According to clause 8,
The first transition metal compound is bis(1-butyl-3-methylcyclopentadienyl)zirconium dichloride, and the second transition metal compound is rac-ethylenebis(tetrahydroindenyl)zirconium dichloride.
According to clause 8,
Polyethylene wherein the molar ratio of the first transition metal compound and the second transition metal compound is 1:1 to 50:1.
According to any one of claims 8 to 10,
Polyethylene that satisfies the requirements of (a) to (c) below:
(a) Hardening stiffness (HS) 104 kg/cm ³ or more;
(b) Lamellae area (LA) greater than 12 m ² /mol;
(c) ESCR acceleration measurements greater than 1100 hours.