KR20240143451A - Catalyst system for producing ethylene-based polymers in a high temperature solution polymerization process and manufacturing method of ethylene-based polymer using the same - Google Patents

Abstract

The present invention relates to a catalyst composition applicable to a high-temperature solution process for producing an ethylene polymer and a method for producing an ethylene polymer using the same. According to the present invention, a low-density ethylene homopolymer or a copolymer of ethylene and alpha-olefin having a broad molecular weight distribution and bimodality can be produced with high activity in a solution polymerization process carried out at high temperatures.

Description

Catalyst composition for producing ethylene-based polymers applicable to high temperature solution polymerization process and manufacturing method of ethylene-based polymer using the same {Catalyst system for producing ethylene-based polymers in a high temperature solution polymerization process and manufacturing method of ethylene-based polymer using the same}

The present invention relates to a catalyst composition for producing an ethylene polymer applicable to a high-temperature solution process and a method for producing an ethylene polymer using the same.

Metallocene catalysts have been used for the production of ethylene homopolymers and copolymers with α-olefins. Metallocenes are currently used industrially and are used not only for polyethylene but also for polypropylene. These metallocenes are often produced using cyclopentadienyl-based catalyst systems with different substitution patterns.

Several of these metallocene catalysts have been described for use in solution polymerization to produce polyethylene homo- or copolymers.

For example, US6313240 describes a catalyst system comprising a hafnocene catalyst complex derived from (A) a biscyclopentadienyl hafnium organometallic compound having (A) 1) one or more substituted cyclopentadienyl ligands or an aromatically fused substituted pentadienyl ligand having no additional substituents on the ligands, 2) one substituted or unsubstituted aromatically fused substituted pentadienyl ligand, and 3) a covalent bridge connecting the two cyclopentadienyl ligands.

This bridge may be a single carbon substituted with two aryl groups, each of which is substituted with a C1-C20 hydrocarbyl or hydrocarbylsilyl group.

Additionally, the catalyst system comprises an activating cocatalyst, which is preferably a precursor ion compound comprising a Group 13 anion substituted with a halogenated tetraaryl.

Recently, research is being conducted to develop a polymer with bimodality by using two types of catalysts: a low-molecular-weight catalyst with an advantage in processability and a high-molecular-weight catalyst that is easy to control properties. Since a high-molecular-weight polymer can characterize the property part and a low-molecular-weight polymer can characterize the processability part, two types of catalysts are mainly used to produce bimodality. In addition, there is a method of using hydrogen to produce a low-molecular-weight polymer, but this has the problem of low activity. In addition, attempts to control bimodality by installing an additional reactor result in increased costs. To solve this problem, a catalyst that has high activity at high temperatures and produces low molecular weights is required, and two types of catalysts can be used together to control bimodality.

Additionally, low molecular weight polymers have the potential to produce ideal polyethylene waxes, increasing the importance of catalysts that can be developed independently.

Meanwhile, a metallocene catalyst linked to a transition metal and a cross-linked Cp-Flu ligand has been disclosed as a catalyst capable of producing a polymer with high catalytic activity and high molecular weight in ethylene homopolymerization or ethylene and alpha-olefin copolymerization under solution polymerization conditions. In US6559253, a structure in which a diphenyl-substituted bridge and an unsubstituted fluorene are linked to one cyclopentadiene ligand is presented as an example. In addition, US6121396 discloses a structure of a Cp-Flu ligand having a diphenyl methylene bridge and substituted with one or more electron donating groups.

In the case of these catalysts, the reactivity with alpha-olefins is significantly improved due to the lowered steric hindrance effect of the catalyst itself, but there are many difficulties in commercially utilizing low-molecular-weight polymers. Therefore, securing a more competitive catalyst system that has the required characteristics of a commercial catalyst based on economic feasibility, such as the ability to produce polymers with excellent high-temperature activity and excellent processability, is becoming important.

US6313240 US6559253 US6121396

In order to overcome the problems of the above-mentioned prior art, the inventors of the present invention conducted research and found that when two transition metal compounds having a specific structure are mixed, a low-density ethylene homopolymer or a copolymer of ethylene and alpha-olefin having a broad molecular weight distribution and bimodality can be produced with high activity in a solution polymerization process performed at high temperature.

Accordingly, the purpose of the present invention is to provide a catalyst composition for producing an ethylene polymer, which can produce a low-density ethylene homopolymer or a copolymer of ethylene and alpha-olefin with a broad molecular weight distribution and bimodality with high activity in a solution polymerization process carried out at high temperature, and a method for producing an ethylene polymer using the same.

One aspect of the present invention provides a catalyst composition for producing an ethylene polymer, comprising: a first transition metal compound represented by the following chemical formula 1; a second transition metal compound represented by the following chemical formula 2; and a cocatalyst selected from an aluminum compound, a boron compound, or a mixture thereof.

[Chemical Formula 1]

[Chemical formula 2]

In the above chemical formulas 1 and 2,

M ¹ is a transition metal in group 4 of the periodic table;

R ¹ to R ⁴ are each independently C1-C20 alkyl or C6-C20 aryl;

R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ are each independently C6-C20 aryl, and the aryl of R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ may be further substituted with C1-C20 alkyl;

R ¹¹ and R ¹² are each independently hydrogen or C1-C20 alkyl;

X ¹ , X ² , X ¹¹ and X ¹² are each independently halogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, (C1-C20 alkylC6-C20 aryl)C1-C20 alkyl, C1-C20 alkoxy, C6-C20 aryloxy, C1-C20 alkylC6-C20 aryloxy, C1-C20 alkoxyC6-C20 aryloxy, -OSiR ^a R ^b R ^c , -SR ^d , -NR ^e R ^f , -PR ^g R ^h or C1-C20 alkylidene;

R ^a to R ^d are each independently C1-C20 alkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, C1-C20 alkylC6-C20 aryl or C3-C20 cycloalkyl;

R ^e to R ^h are each independently C1-C20 alkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, C1-C20 alkylC6-C20 aryl or C3-C20 cycloalkyl;

If one of X ¹ and X ² is C1-C20 alkylidene, the other is absent;

If one of X ¹¹ and X ¹² is a C1-C20 alkylidene, the other is absent.

In addition, another aspect of the present invention provides a method for producing an ethylene polymer by polymerizing an ethylene monomer in the presence of the catalyst composition for producing the ethylene polymer.

The catalyst composition according to the present invention maintains high catalytic activity by mixing and using two types of transition metal compounds having specific structures in high-temperature solution polymerization, and can produce a low-density polymer having good copolymerization reactivity with other olefins and a broad molecular weight distribution in a high yield. In addition, the catalyst composition according to the present invention can produce a low-density ethylene polymer having a broad molecular weight distribution and bimodality, and the produced ethylene polymer can secure excellent processability. Therefore, the catalyst composition according to the present invention can be usefully used in the production of ethylene homopolymers having various physical properties or copolymers with alpha-olefins.

Figure 1 - GPC graph of the copolymer prepared in Example 2

The present invention will be described in more detail. In this description, if there is no other definition for the technical and scientific terms used, they have the meaning commonly understood by a person of ordinary skill in the technical field to which this invention belongs, and in the following description, descriptions of well-known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted.

As used herein, the singular form may be intended to include the plural form as well, unless the context clearly indicates otherwise.

The term "comprises" as used herein is an open-ended statement equivalent to the words "comprises," "contains," "has," or "characterized by," and does not exclude additional elements, materials, or processes not listed herein.

The term "alkyl" as used herein means a monovalent straight-chain or branched saturated hydrocarbon radical composed solely of carbon and hydrogen atoms, examples of which include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, nonyl, and the like.

The "aryl" described herein is an organic radical derived from an aromatic hydrocarbon by the removal of one hydrogen, including a single or fused ring system having suitably 4 to 7, preferably 5 or 6 ring atoms in each ring, and even including a form in which multiple aryls are connected by single bonds. The fused ring system may include an aliphatic ring such as a saturated or partially saturated ring, and necessarily includes at least one aromatic ring. In addition, the aliphatic ring may contain nitrogen, oxygen, sulfur, carbonyl, etc. in the ring. Specific examples of the aryl radical include, but are not limited to, phenyl, naphthyl, biphenyl, indenyl, fluorenyl, phenanthrenyl, anthracenyl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl, 9,10-dihydroanthracenyl, and the like.

As used herein, "cycloalkyl" means a monovalent saturated carbocyclic radical consisting of one or more rings. Examples of cycloalkyl radicals include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and the like.

As used herein, “halo” or “halogen” means a fluorine, chlorine, bromine or iodine atom.

As used herein, “alkoxy” means -O-(alkyl) including -OCH ₃ , -OCH ₂ CH ₃ , -O(CH ₂ ) ₂ CH ₃ , -O(CH ₂ ) ₃ CH ₃ , -O(CH ₂ ) ₄ CH ₃ , -O(CH ₂ ) ₅ CH ₃ and the like, wherein alkyl is as defined above.

As used herein, “aryloxy” refers to an -O-aryl radical, where “aryl” is as defined above.

The term "alkylidene" as used herein means a straight or branched chain saturated divalent hydrocarbon group having a valence of 2 on one common carbon atom.

In this specification, (co)polymer means both a homopolymer and a copolymer.

Unless otherwise defined herein, “copolymerization” may mean a block copolymer, a random copolymer, a graft copolymer or an alternating copolymer, and “copolymer” may mean a block copolymer, a random copolymer, a graft copolymer or an alternating copolymer.

Hereinafter, the present invention will be described in detail.

One aspect of the present invention provides a catalyst composition for producing an ethylene polymer in a high-temperature solution process, wherein the catalyst composition for producing an ethylene polymer according to one aspect comprises: a first transition metal compound represented by the following chemical formula 1; a second transition metal compound represented by the following chemical formula 2; and a cocatalyst selected from an aluminum compound, a boron compound, or a mixture thereof.

[Chemical Formula 1]

[Chemical formula 2]

In the above chemical formulas 1 and 2

M ¹ is a transition metal in group 4 of the periodic table;

R ¹ to R ⁴ are each independently C1-C20 alkyl or C6-C20 aryl;

R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ are each independently C6-C20 aryl, and the aryl of R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ may be further substituted with C1-C20 alkyl;

R ¹¹ and R ¹² are each independently hydrogen or C1-C20 alkyl;

X ¹ , X ² , X ¹¹ and X ¹² are each independently halogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, (C1-C20 alkylC6-C20 aryl)C1-C20 alkyl, C1-C20 alkoxy, C6-C20 aryloxy, C1-C20 alkylC6-C20 aryloxy, C1-C20 alkoxyC6-C20 aryloxy, -OSiR ^a R ^b R ^c , -SR ^d , -NR ^e R ^f , -PR ^g R ^h or C1-C20 alkylidene;

R ^a to R ^d are each independently C1-C20 alkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, C1-C20 alkylC6-C20 aryl or C3-C20 cycloalkyl;

R ^e to R ^h are each independently C1-C20 alkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, C1-C20 alkylC6-C20 aryl or C3-C20 cycloalkyl;

If one of X ¹ and X ² is C1-C20 alkylidene, the other is absent;

If one of X ¹¹ and X ¹² is a C1-C20 alkylidene, the other is absent.

According to one embodiment, a catalyst composition for producing an ethylene polymer can produce an ethylene polymer having a bimodal property with high activity in a solution polymerization process performed at high temperature by satisfying a combination of a first transition metal compound, a second transition metal compound, and a cocatalyst having a specific structure. In addition, according to one embodiment, a catalyst composition for producing an ethylene polymer can produce a low-density ethylene polymer having high activity and a broad molecular weight distribution by satisfying the above-described combination of components. In addition, according to one embodiment, a catalyst composition for producing an ethylene polymer can produce a low-density ethylene polymer having bimodality and a broad molecular weight distribution under polymerization conditions of high temperature and high pressure by satisfying the above-described combination of components.

The transition metals of the above group 4 include titanium (Ti), zirconium (Zr), hafnium (Hf), etc., and specifically, it may be zirconium (Zr) or hafnium (Hf).

In the above chemical formula 1, M ¹ is Zr or Hf; R ¹ to R ⁴ are each independently C1-C20 alkyl or C6-C20 aryl; R ⁵ and R ⁶ are each independently C6-C20 aryl, and the aryl of R ⁵ and R ⁶ may be further substituted with C1-C20 alkyl; X ¹ and X ² may each independently be halogen, C1-C20 alkyl, C6-C20 aryl or C6-C20 arylC1-C20 alkyl.

Specifically, in the chemical formula 1, M ¹ is Hf; R ¹ to R ⁴ are each independently C1-C10 alkyl or C6-C12 aryl; R ⁵ and R ⁶ are each independently C6-C12 aryl, and the aryl of R ⁵ and R ⁶ may be further substituted with C1-C10 alkyl; X ¹ and X ² may each independently be halogen, C1-C10 alkyl, C6-C12 aryl or C6-C12 arylC1-C10 alkyl.

In the above chemical formula 2, R ¹¹ and R ¹² are each independently hydrogen or C1-C20 alkyl; R ¹⁵ and R ¹⁶ are each independently C6-C20 aryl, and the aryl of R ¹⁵ and R ¹⁶ may be further substituted with C1-C20 alkyl; X ¹¹ and X ¹² may each independently be halogen, C1-C20 alkyl, C6-C20 aryl or C6-C20 arylC1-C20 alkyl.

Specifically, in the above chemical formula 2, R ¹¹ and R ¹² are each independently hydrogen or C1-C10 alkyl; R ¹⁵ and R ¹⁶ are each independently C6-C12 aryl, and the aryl of R ¹⁵ and R ¹⁶ may be further substituted with C1-C10 alkyl; X ¹¹ and X ¹² may each independently be halogen, C1-C10 alkyl, C6-C12 aryl or C6-C12 arylC1-C10 alkyl.

이고, R²¹은 C1-C10알킬이고; a는 0 내지 5의 정수이며; X¹ 및 X²는 각각 독립적으로 할로겐, C1-C6알킬, C6-C12아릴 또는 C6-C12아릴C1-C6알킬일 수 있다.More specifically, in the chemical formula 1, M ¹ is Hf; R ¹ to R ⁴ are the same as each other and are C1-C10 alkyl or C6-C12 aryl; R ⁵ and R ⁶ are each independently

, R ²¹ is C1-C10 alkyl; a is an integer from 0 to 5; X ¹ and X ² can each independently be halogen, C1-C6 alkyl, C6-C12 aryl or C6-C12 arylC1-C6 alkyl.

이고, R²¹은 C1-C10알킬이고; a는 0 내지 5의 정수이며; X¹¹ 및 X¹²는 각각 독립적으로 할로겐, C1-C6알킬, C6-C12아릴 또는 C6-C12아릴C1-C6알킬일 수 있다.More specifically, in the above chemical formula 2, R ¹¹ and R ¹² are the same as each other and are hydrogen or C1-C10 alkyl; R ¹⁵ and R ¹⁶ are each independently

, R ²¹ is C1-C10 alkyl; a is an integer from 0 to 5; X ¹¹ and X ¹² can each independently be halogen, C1-C6 alkyl, C6-C12 aryl or C6-C12 arylC1-C6 alkyl.

The above first transition metal compound is [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenyl methane]hafnium dichloro, [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenyl methane]hafnium dibenzyl, or [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenyl methane]hafnium dimethyl;

The above second transition metal compounds are [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dichloro, [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dibenzyl, [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dimethyl, [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dichloro, [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dibenzyl, or [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dimethyl.

The first transition metal compound of the above chemical formula 1 has a group 4 transition metal as a central metal and a fluorene ligand with an amine substituent having a large electron donating effect introduced at positions 2 and 7, which are far from the active site, so it has high activity in high-temperature solution polymerization and can be useful as a catalyst capable of producing a low-molecular-weight ethylene polymer.

The first transition metal compound of the above chemical formula 1, when combined with the second transition metal compound of the above chemical formula 2 which produces a high molecular weight polymer, has high activity in high temperature solution polymerization, has a wide molecular weight distribution and bimodality, and thus not only has excellent physical properties but also excellent processability, and can produce a low-density ethylene polymer.

In order to produce a low-density ethylene polymer having a broad molecular weight distribution and bimodality, the first transition metal compound of the chemical formula 1 and the second transition metal compound of the chemical formula 2 can be used in a molar ratio of 1:0.2 to 1:1.5. More specifically, the first transition metal compound of the chemical formula 1 and the second transition metal compound of the chemical formula 2 can be mixed in a molar ratio of 1:0.5 to 1:1.5, or 1:0.5 to 1:1.

The above-mentioned cocatalyst can act as a scavenger that activates the transition metal compound while removing impurities that act as catalyst poisons.

The aluminum compound used as the above-mentioned cocatalyst may be one or more selected from an aluminoxane compound and an organoaluminum compound, and the aluminoxane compound may be represented by the following chemical formula A or B, and the organoaluminum compound may be represented by the following chemical formula C.

[Chemical Formula A]

(R ^a ) ₂ Al-(-O(R ^a )-) _p -(R ^a ) ₂

[Chemical Formula B]

(-Al(R ^a )-O-) _q

[Chemical Formula C]

(R ^b ) _r Al(E) _3-r

In the above chemical formulas A to C,

R ^a is C1-C20 alkyl; p and q are each independently an integer from 5 to 20; R ^b is C1-C20 alkyl; E is hydrogen or halogen; r is an integer from 1 to 3.

In the above chemical formulas A and B, R ^a can be methyl or isobutyl.

Examples of the above aluminoxane compounds include methylaluminoxane, modified methylaluminoxane, tetraisobutylaluminoxane, etc.; Examples of the above organoaluminum compounds include trialkylaluminum including trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, and trioctylaluminum, dialkylaluminum chloride including dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diisobutylaluminum chloride, and dihexylaluminum chloride, alkylaluminum dichlorides including methylaluminum dichloride, ethylaluminum dichloride, propylaluminum dichloride, isobutylaluminum dichloride, and hexylaluminum dichloride, dimethylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, diisobutylaluminum hydride, and dihexylaluminum hydride. Examples thereof include dialkyl aluminum hydrides, etc.

Preferably, the aluminum compound may be one or more selected from methylaluminoxane, modified methylaluminoxane, tetraisobutylaluminoxane, trimethylaluminium, triethylaluminium, trioctylaluminium and triisobutylaluminium.

The boron compound used as the above-mentioned cocatalyst can be selected from boron compounds represented by the following chemical formulas D to F.

[Chemical Formula D]

B(R ^c ) ₃

[Chemical formula E]

[R ^d ] ⁺ [B(R ^c ) ₄ ] ^-

[Chemical formula F]

[(R ^e ) _s ZH] ⁺ [B(R ^c ) ₄ ] ^-

In the above chemical formulas D to F,

B is a boron atom; R ^c is phenyl, wherein said phenyl may be further substituted with 3 to 5 substituents selected from fluorine, C1-C20 alkyl substituted or unsubstituted by fluorine, and C1-C20 alkoxy substituted or unsubstituted by fluorine; R ^d is a C5-C7 aromatic radical or a C1-C20 alkylC6-C20 aryl radical, a C6-C20 arylC1-C20 alkyl radical, for example, a triphenylmethylium radical; Z is a nitrogen or phosphorus atom; R ^e is a C1-C20 alkyl radical or anilinium radical substituted with two C1-C10 alkyls together with the nitrogen atom; s is an integer of 2 or 3.

Examples of the above boron compounds include dimethylphenylammonium tetra(phenyl)borate, trityl tetra(phenyl)borate, dimethylphenylammonium tetra(pentafluorophenyl)borate, trityl tetrakis(pentafluorophenyl)borate, trimethylammonium tetra(phenyl)borate, triethylammonium tetra(phenyl)borate, tripropylammonium tetra(phenyl)borate, tributylammonium tetra(phenyl)borate, trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, anilinium tetra(phenyl)borate, anilinium tetrakis(pentafluorophenyl)borate, pyridinium tetrakis(pentafluorophenyl)borate, etc.

The above-mentioned cocatalyst may specifically be a combination of an organoaluminum compound and a boron compound.

More specifically, the above cocatalyst may be a combination of an organoaluminum compound of the above chemical formula C and a boron compound of the above chemical formula E or F.

The above cocatalyst is one or more trialkylaluminum selected from trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, and trioctylaluminum, and dimethylphenylammonium tetra(phenyl)borate, trityl tetra(phenyl)borate, dimethylphenylammonium tetra(pentafluorophenyl)borate, trityl tetrakis(pentafluorophenyl)borate, trimethylammonium tetra(phenyl)borate, triethylammonium tetra(phenyl)borate, tripropylammonium tetra(phenyl)borate, tributylammonium tetra(phenyl)borate, trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tributylammonium It may be a combination of one or more boron compounds selected from tetrakis(pentafluorophenyl)borate, anilinium tetra(phenyl)borate, anilinium tetrakis(pentafluorophenyl)borate and pyridinium tetrakis(pentafluorophenyl)borate.

The above cocatalyst can be used in an appropriate amount so that the activation of the first transition metal compound of the above chemical formula 1 and the second transition metal compound of the above chemical formula 2 can proceed sufficiently.

For example, when the aluminum compound and the boron compound are used simultaneously as cocatalysts, a preferable range of the ratio between the total transition metal compound (first transition metal compound + second transition metal compound) and the cocatalyst included in the catalyst composition may be a molar ratio of transition metal (M): aluminum atoms (Al): boron atoms (B) of 1:(10 to 3,000):(1 to 100), more preferably 1:(100 to 1,000):(3 to 10).

If the ratio between the entire transition metal compound and the cocatalyst is out of the above range, the amount of the cocatalyst may be relatively small, so that the activation of the transition metal compound may not be completely achieved, and thus the catalytic activity of the transition metal compound may not be sufficient, or an excessive amount of cocatalyst may be used, which may cause a problem in that the production cost significantly increases. Excellent catalytic activity for producing an ethylene polymer is exhibited within the above range, and the range of the ratio varies depending on the purity of the reaction.

The above catalyst composition may further include one or more C5-C12 aliphatic hydrocarbon solvents selected from pentane, hexane, heptane, octane, isooctane, nonane, decane, dodecane, cyclohexane and methylcyclohexane as a reaction solvent.

Since the above catalyst composition exists in a uniform form within a polymerization reactor, it is preferable to apply it to a high-temperature solution polymerization process of 110°C or higher.

Another aspect of the present invention provides a method for producing an ethylene polymer by polymerizing an ethylene monomer in the presence of the catalyst composition for producing an ethylene polymer.

The above ethylene monomer is ethylene or α-olefin; specifically, when producing an ethylene homopolymer, ethylene is used solely as a monomer, and when producing a copolymer of ethylene and α-olefin, one or more selected from among (C3~C18) α-olefin, (C5~C20) cycloolefin, styrene, and derivatives of styrene may be used as a comonomer copolymerized with ethylene. Preferred examples of the (C3~C18)α-olefin may be selected from the group consisting of propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene and 1-octadecene; preferred examples of the (C5~C20)cycloolefin may be selected from the group consisting of cyclopentene, cyclohexene, norbonene and phenylnorbornene; and styrene and its derivatives may be selected from styrene, α-methylstyrene, p-methylstyrene and 3-chloromethylstyrene. More preferably, the α-olefin may be one or more selected from 1-butene, 1-hexene, 1-octene and 1-decene.

The above manufacturing method can be carried out by contacting the catalyst composition for manufacturing an ethylene polymer according to one embodiment, and ethylene or, if necessary, a comonomer, in the presence of a suitable organic solvent. At this time, the first transition metal compound, the second transition metal compound, and the cocatalyst component can be separately introduced into the reactor, or each component can be mixed in advance and introduced into the reactor, and there are no separate restrictions on the mixing conditions such as the order of introduction, temperature, or concentration.

The above polymerization reaction can be performed at a temperature of 110°C to 170°C, specifically 120°C to 160°C, and under a pressure of 10 to 100 bar, and more specifically at a temperature of 130°C to 150°C and under a pressure of 15 to 50 bar.

In addition, the above manufacturing method can be performed in a C5-C12 aliphatic hydrocarbon solvent, and specifically, the C5-C12 aliphatic hydrocarbon solvent can be one or two or more selected from pentane, hexane, heptane, octane, isooctane, nonane, decane, dodecane, cyclohexane and methylcyclohexane, and preferably can be hexane, cyclohexane or a mixture thereof.

The above manufacturing method according to one embodiment is a more economical manufacturing method because it does not use toluene, a common solvent generally used in the manufacture of existing copolymers, and thus the toluene solvent removal step in the manufacturing process is reduced.

The ethylene polymer prepared according to one embodiment may be an ethylene homopolymer.

In one embodiment, the ethylene polymer manufactured may be a copolymer of ethylene and an α-olefin. The copolymer of ethylene and an α-olefin contains 50 wt% or more of ethylene, preferably 60 wt% or more of ethylene, and more preferably 60 to 99 wt% of ethylene. The density of the copolymer of ethylene and an α-olefin may be 0.900 g/cm3 or less, specifically 0.850 g/cm3 to 0.900 g/cm3, and may have a molecular weight distribution (Mw/Mn) of 4 or more, specifically 4.5 to 8.0, and may have bimodality.

In general, as the molecular weight distribution is wide, the viscosity decreases as the shear stress (Shear Rate) decreases, so the processability is improved, but the physical properties such as strength are deteriorated. However, in the case of bimodality and a wide molecular weight distribution, the processability is improved and the physical properties can be enhanced depending on the catalyst type.

The present invention is specifically described through the following examples, but the scope of the present invention is not limited by the following examples.

[Materials and analytical equipment]

All the synthetic reactions below were carried out under an inert atmosphere such as nitrogen or argon, and standard Schlenk and glove box techniques were used. Synthetic solvents such as tetrahydrofuran (THF), n-hexane, n-pentane, diethyl ether, and methylene chloride (CH ₂ Cl ₂ ) were used after removing moisture by passing through an activated alumina column and storing on activated molecular sieves. Most of the reagents were purchased from Sigma-Aldrich, TCI, Alfa, and Strem unless otherwise stated. ¹ H NMR analysis of the synthesized ligands and catalysts was performed using a Bruker 500 MHz at room temperature.

[Measurement of physical properties]

The polymerized polymer was analyzed by the method described below.

1. Polymerization activity

Polymerization activity (kg/g cat) was calculated as the weight ratio of polymer produced per amount of catalyst used.

2. Melt Flow Index (MI)

Measured at 190°C under a load of 2.16 kg according to ASTM D1238.

3. Density

Measured in Density Gradient Column by ASTM D1505 method.

4. Molecular weight distribution

Molecular weight distribution was measured using GPC (Gel Permeation Chromatography) at 150°C using 1,2,4-trichlorobenzene as a solvent, and the weight average molecular weight (Mw) and number average molecular weight (Mn) were calculated by dividing the measured Mw by Mn.

[Catalyst Preparation Example 1] Preparation of [1-(η5-Cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenylmethane]hafnium dichloro (CAT-1)

[1-(η5-Cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dichloro (CAT-1) was synthesized by the procedure reported in the literature [A. Razavi, J. L. Atwood, J. Organometallic. Chen, 459 (1993), 117-123].

^1H NMR (500 MHz, Chloroform- d ) δ 8.19 (d, J = 8.5 Hz, 2H), 7.95 (d, J = 8.3 Hz, 2H), 7.88 (d, J = 8.5 Hz, 2H), 7.55 ( t, J = 8.0 Hz, 2H), 7.44 (t, J = 8.2 Hz, 2H), 7.31 (m, 4H), 7.01 (t, J = 8.1 Hz, 2H), 6.47 (d, J = 7.1 Hz, 2H), 6.33 (s, 2H), 5.75 (s, 2H)

[Catalyst Preparation Example 2] Preparation of [1-(η5-Cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenylmethane]hafnium dichloro (CAT-2)

Step 1: Preparation of 1-(cyclopentadien-1-yl)-1-(2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane (a1)

2,7-Di-tertbutylfluorene (12 g, 43.1 mmol) was dissolved in THF (87 mL), n-BuLi (1.6 M in Hex, 27.1 mL, 43.1 mmol) was added, and the mixture was stirred at room temperature. After 3 h, 6,6-Diphenylfulvene (10 g, 43.1 mmol) was added. The reaction solution was stirred for 16 h, and then NH ₄ Cl aqueous solution (40 mL) was poured to quench the reaction. The product was extracted into the organic layer, dried over MgSO ₄ , filtered, and under reduced pressure. The yellow solid produced was washed with ethanol to obtain a white solid ligand a1 (20 g, yield 93%).

¹ H NMR (500 MHz, Chloroform- d ) δ 6.21~7.35 (m, 20H), 5.45 (s, 1H), 3.01 (m, 1H), 1.14 (s, 18H)

Step 2: Preparation of [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dichloro (CAT-2)

1-(Cyclopentadien-1-yl)-1-(2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane (a1, 5 g, 9.82 mmol) is dissolved in 60 mL of ether, n-BuLi (1.6 M in Hex, 13.5 mL, 21.6 mmol) is added, and the mixture is stirred for 16 hours. After completion of the reaction, ether is removed by vacuum drying, and n-hexane is added, decant, and the pressure is reduced. In a glove box, the lithiated intermediate a2 (5.1 g, 9.79 mmol) and HfCl ₄ (3.13 g, 9.79 mmol) are separated and dissolved in 80 mL of ether. After stirring at room temperature for 16 hours, ether was removed by vacuum drying, 80 mL of toluene was added, heated at 50°C for 2 hours, and the produced LiCl was precipitated and filtered. The filtrate was vacuum dried and crystallized to obtain 4.4 g of CAT-2 as yellow crystals (recrystallized from toluene, yield 60%).

[Catalyst Preparation Example 3] Preparation of [1-(η5-Cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenylmethane]hafnium dichloro (CAT-3)

Step 1: Preparation of 2,7-di-dimethylaminefluorene (b1)

In a Schlenk flask, add NaBH ₄ (7.7 g, 203.8 mmol) and 2,7-DiaminoFluorene (5 g, 25.4 mmol), and maintain at 0℃. Add ethanol (50 mL), acetic acid (7.27 mL, 127 mmol), and then paraformaldehyde (11.5 g, 382 mmol). After 16 hours, extract three times using saturated NHCO ₃ aqueous solution and ether. The organic layers are collected, dried over MgSO ₄ , filtered, and reduced pressure. After recrystallization using hexane, 2,7-di-dimethylaminefluorene (b1) was obtained as a yellow solid (5.1 g, 80%).

^1H NMR (500 MHz, Chloroform- d ) δ 7.50 (d, J = 8.5 Hz, 2H), 6.93 (d, J = 2.0 Hz, 2H), 6.76 (d, J = 7.7 Hz, 2H), 3.81 ( s, 2H), 2.98 (s, 12H).

Step 2: Preparation of 1-(cyclopentadien-1-yl)-1-(2,7-di-n-butylfluorenyl)-1,1-diphenyl methane (b2)

2,7-Di-dimethylaminefluorene (b1, 12 g, 43.1 mmol) was dissolved in THF (87 mL), n-BuLi (1.6 M in Hex, 27.1 mL, 43.1 mmol) was added, and the mixture was stirred at room temperature. After 3 h, 6,6-Diphenylfulvene (10 g, 43.1 mmol) was added. The reaction solution was stirred for 16 h, and then NH ₄ Cl aqueous solution (40 mL) was poured to quench the reaction. The product was extracted into the organic layer, dried over MgSO ₄ , filtered, and under reduced pressure. The yellow solid produced was washed with ethanol to obtain a brown solid ligand b2 (20 g, yield 91%).

Step 3: Preparation of [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenylmethane]hafnium dichloro (CAT-3)

1-(Cyclopentadien-1-yl)-1-(2,7-di-dimethylaminebutylfluorenyl)-1,1-diphenyl methane (b2, 5 g, 9.82 mmol) is dissolved in 60 mL of ether, n-BuLi (1.6 M in Hex, 13.5 mL, 21.6 mmol) is added, and the mixture is stirred for 16 hours. After the reaction is complete, ether is removed by vacuum drying, and n-hexane is added, decant, and the pressure is reduced. In a glove box, the lithiated intermediate b3 (5.1 g, 9.79 mmol) and HfCl ₄ (3.13 g, 9.79 mmol) are separated and dissolved in 80 mL of ether. After stirring at room temperature for 16 hours, ether was removed by vacuum drying, 80 mL of toluene was added, and the mixture was heated at 50°C for 2 hours. The produced LiCl was precipitated and filtered. The filtrate was vacuum dried and crystallized to obtain 4.5 g of CAT-3 as yellow crystals (recrystallized from toluene, yield 60%).

Example 1: Preparation of copolymer of ethylene and 1-octene

At room temperature, 1 L of hexane and 2 mL of triisobutyl aluminum (TIBA) (1 M in Hex) were injected into a 4 L reactor, followed by 100 mL of 1-octene. In a glove box, catalysts CAT-1 (3.9 μmol) and CAT-3 (3.9 μmol) were weighed and mixed with 2 mL of TIBA (0.1 M in Hex), and 5 mL of toluene was additionally added and injected into the reactor inlet. In a glove box, 19.5 μmol of trityl tetrakis(pentafluorophenyl)borate was mixed with 5 mL of toluene and injected into the reactor inlet. After raising the reactor temperature to 140 ℃, the solution in the inlet was forced into the reactor using high-pressure nitrogen. Ethylene injection was performed at 21 bar for 15 minutes, and it was shown that the initial temperature increased in proportion to the activity. After polymerization was completed, the reactor temperature was cooled to 30°C, and the ethylene pressure inside the reactor was slowly exhausted to remove it. The reaction product was washed with ethanol and acetone, filtered, and vacuum-dried. The properties of the obtained polymer are listed in Table 1 below.

Example 2

Polymerization was performed by following the same procedure as in Example 1, except that CAT-2 was used instead of CAT-1 in Example 1, and the properties of the obtained polymer are listed in Table 1 below.

Comparative Example 1

Polymerization was performed in the same manner as in Example 1, except that a Ph ₂ C(Cp)(Flu)ZrCl ₂ (diphenylmethylidene(cyclopentadienyl)(9-fluorenyl)zirconium dichloride) catalyst was used instead of CAT-1 in Example 1, and the properties of the obtained polymer are listed in Table 1 below.

Comparative Example 2

Polymerization was performed in the same manner as in Example 1, except that Et(IND) ₂ ZrCl ₂ (ethylenebis(indenyl)zirconium dichloride) catalyst was used instead of CAT-1 in Example 1, and the properties of the obtained polymer are listed in Table 1 below.

Comparative Example 3

Polymerization was performed in the same manner as in Example 1, except that Et(THI) ₂ ZrCl ₂ (ethylenebis(tetrahydroindenyl)zirconium Dichloride) catalyst was used instead of CAT-1 in Example 1, and the properties of the obtained polymer are listed in Table 1 below.

Comparative Example 4

Polymerization was performed by following the same procedure as in Example 1, except that CAT-3 was not used and only the catalyst CAT-1 (7.8 μmol) was used, and the properties of the obtained polymer are listed in Table 1 below.

Comparative Example 5

Polymerization was performed by following the same procedure as in Example 1, except that CAT-3 and CAT-1 were not used and only the catalyst CAT-2 (7.8 μmol) was used, and the properties of the obtained polymer are listed in Table 1 below.

Comparative Example 6

Polymerization was performed by following the same procedure as in Example 1, except that CAT-1 was not used and only the catalyst CAT-3 (7.8 μmol) was used, and the properties of the obtained polymer are listed in Table 1 below.

Ethylene/1-octene copolymerization conditions and results Polymerization example Transition metal catalyst Active
(kg/g cat) MI
(2.16 Kg/10min) density
(g/cm ³ ) Molecular weight distribution
(Mw/Mn) Example 1 CAT-1 CAT-3 10.5 0.77 0.883 4.8 Example 2 CAT-2 CAT-3 27.3 1.2 0.872 7.8 1 in comparison Ph ₂ C(Cp)(Flu)ZrCl ₂ CAT-3 15.6 23.2 0.910 3.2 Comparative Example 2 Et(IND) ₂ ZrCl ₂ CAT-3 17.8 17.2 0.921 2.4 3 in comparison Et(THI) ₂ ZrCl ₂ CAT-3 12.8 15.1 0.902 2.7 Comparative Example 4 CAT-1 1.8 0.9142 0.8603 2.32 Comparative Example 5 CAT-2 10.5 0.2291 0.8678 2.09 Comparative Example 6 CAT-3 7.2 10.291 0.8948 2.57 CAT-1 : CAT-2 :
CAT-3 : Ph ₂ C(Cp)(Flu)ZrCl ₂ :
Et(IND) ₂ ZrCl ₂ : Et(THI) ₂ ZrCl ₂ :

As shown in Table 1 above, as can be seen from the results of ethylene/1-octene copolymerization of Examples 1 and 2, it can be confirmed that the polymers produced by the novel catalyst system of the present invention, that is, the combination of CAT-3 and CAT-1 (Example 1) and the combination of CAT-3 and CAT-2 (Example 2), have a wide molecular weight distribution of 4 or more and a low density of 0.9 or less.

In Comparative Examples 4 to 6 where CAT-1, CAT-2, and CAT-3 are used alone, the molecular weight distribution is shown to be narrow, and the combination of Ph ₂ C(Cp)(Flu)ZrCl ₂ and CAT-3 (Comparative Example 1), the combination of Et(IND) ₂ ZrCl ₂ and CAT-3 (Comparative Example 2), and the combination of Et(THI) ₂ ZrCl ₂ and CAT-3 (Comparative Example 3) show narrow molecular weight distribution and a high density of 0.9 or higher.

FIG. 1 shows GPC data of Example 2 using CAT-3 and CAT-2 as polymerization catalysts. As in Examples 1 and 2 of the present invention, when CAT-3, which produces a low molecular weight polymer, and CAT-1 and CAT-2, which produce high molecular weight polymers, are combined and used as a polymerization catalyst, it can be seen that a bimodal polymer is produced, as shown in FIG. 1.

That is, it can be seen that the novel catalyst system according to the present invention is a catalyst system capable of obtaining a low-density polymer with a broad molecular weight distribution and bimodality under high temperature and high pressure polymerization conditions.

Although the embodiments of the present invention have been described in detail as described above, it will be apparent to those skilled in the art that various modifications may be made to the present invention without departing from the scope of the present invention as defined in the appended claims. Accordingly, modifications to future embodiments of the present invention will not be able to depart from the technology of the present invention.

Claims (13)

A first transition metal compound represented by the following chemical formula 1;
A second transition metal compound represented by the following chemical formula 2; and
A catalyst composition for producing an ethylene polymer, comprising a cocatalyst selected from an aluminum compound, a boron compound or a mixture thereof.
[Chemical Formula 1]

[Chemical formula 2]

In the above chemical formulas 1 and 2
M ¹ is a transition metal in group 4 of the periodic table;
R ¹ to R ⁴ are each independently C1-C20 alkyl or C6-C20 aryl;
R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ are each independently C6-C20 aryl, and the aryl of R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ may be further substituted with C1-C20 alkyl;
R ¹¹ and R ¹² are each independently hydrogen or C1-C20 alkyl;
X ¹ , X ² , X ¹¹ and X ¹² are each independently halogen, C1-C20 alkyl, C3-C20 cycloalkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, (C1-C20 alkylC6-C20 aryl)C1-C20 alkyl, C1-C20 alkoxy, C6-C20 aryloxy, C1-C20 alkylC6-C20 aryloxy, C1-C20 alkoxyC6-C20 aryloxy, -OSiR ^a R ^b R ^c , -SR ^d , -NR ^e R ^f , -PR ^g R ^h or C1-C20 alkylidene;
R ^a to R ^d are each independently C1-C20 alkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, C1-C20 alkylC6-C20 aryl or C3-C20 cycloalkyl;
R ^e to R ^h are each independently C1-C20 alkyl, C6-C20 aryl, C6-C20 arylC1-C20 alkyl, C1-C20 alkylC6-C20 aryl or C3-C20 cycloalkyl;
If one of X ¹ and X ² is C1-C20 alkylidene, the other is absent;
If one of X ¹¹ and X ¹² is a C1-C20 alkylidene, the other is absent. In the first paragraph,
The above M ¹ is Zr or Hf;
R ¹ to R ⁴ are each independently C1-C20 alkyl or C6-C20 aryl;
R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ are each independently C6-C20 aryl, and the aryl of R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ may be further substituted with C1-C20 alkyl;
R ¹¹ and R ¹² are each independently hydrogen or C1-C20 alkyl;
A catalyst composition for producing an ethylene polymer, wherein X ¹ , X ² , X ¹¹ and X ¹² are each independently halogen, C1-C20 alkyl, C6-C20 aryl or C6-C20 arylC1-C20 alkyl. In paragraph 1,
The above M ¹ is Hf;
R ¹ to R ⁴ are each independently C1-C10 alkyl or C6-C12 aryl;
R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ are each independently C6-C12 aryl, and the aryl of R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ may be further substituted with C1-C10 alkyl;
R ¹¹ and R ¹² are each independently hydrogen or C1-C10 alkyl;
A catalyst composition for producing an ethylene polymer, wherein X ¹ , X ² , X ¹¹ and X ¹² are each independently halogen, C1-C10 alkyl, C6-C12 aryl or C6-C12 arylC1-C10 alkyl. In paragraph 1,
The above M ¹ is Hf;
R ¹ to R ⁴ are the same as each other and are C1-C10 alkyl or C6-C12 aryl;
R ⁵ , R ⁶ , R ¹⁵ and R ¹⁶ are each independently

, R ²¹ is C1-C10 alkyl; a is an integer from 0 to 5;
R ¹¹ and R ¹² are the same as each other and are hydrogen or C1-C10 alkyl;
A catalyst composition for producing an ethylene polymer, wherein X ¹ , X ² , X ¹¹ and X ¹² are each independently halogen, C1-C6 alkyl, C6-C12 aryl or C6-C12 arylC1-C6 alkyl. In paragraph 1,
The above first transition metal compound is [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenyl methane]hafnium dichloro, [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenyl methane]hafnium dibenzyl, or [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-dimethylaminefluorenyl)-1,1-diphenyl methane]hafnium dimethyl;
The above second transition metal compounds are [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dichloro, [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dibenzyl, [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenyl methane]hafnium dimethyl, [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dichloro, A catalyst composition for producing an ethylene polymer, wherein the catalyst composition is selected from the group consisting of [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dibenzyl, or [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-tertbutylfluorenyl)-1,1-diphenyl methane]hafnium dimethyl. In paragraph 1,
A catalyst composition for producing an ethylene polymer, wherein the aluminum compound is one or more selected from an aluminoxane compound and an organoaluminum compound. In paragraph 1,
The above aluminum compound is selected from methylaluminoxane, modified methylaluminoxane, tetraisobutylaluminoxane, trimethylaluminoxane, triethylaluminium, triisobutylaluminium, trihexylaluminium and trioctylaluminium, alone or in combination, a catalyst composition for producing an ethylene polymer. In paragraph 1,
A catalyst composition for producing an ethylene polymer, wherein the boron compound is one or more selected from dimethylphenylammonium tetraphenylborate, trityl tetraphenylborate, dimethylphenylammonium tetra(pentafluorophenyl)borate, trityl tetrakis(pentafluorophenyl)borate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tributylammonium tetraphenylborate, trimethylammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tributylammonium tetrakis(pentafluorophenyl)borate, anilinium tetraphenylborate, anilinium tetrakis(pentafluorophenyl)borate, and pyridinium tetrakis(pentafluorophenyl)borate. A method for producing an ethylene polymer by polymerizing an ethylene monomer in the presence of a catalyst composition for producing an ethylene polymer according to any one of claims 1 to 8. In Article 9,
A manufacturing method wherein the above ethylene polymer is an ethylene homopolymer or a copolymer of ethylene and α-olefin. In Article 10,
The above ethylene monomer is ethylene or α-olefin;
A manufacturing method according to claim 1, wherein the α-olefin copolymerized with the ethylene is one or more selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, cyclopentene, cyclohexene, norbonene, phenylnorbornene, 1,4-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, p-methylstyrene, divinylbenzene, and 3-chloromethylstyrene. In Article 9,
A manufacturing method wherein the above polymerization reaction is performed at a temperature of 120 to 160° C. and a pressure of 10 to 100 bar. In Article 9,
A manufacturing method wherein the above polymerization reaction is carried out in a C5-C12 aliphatic hydrocarbon solvent.