NOVEL TRANSITION METAL COMPOUND, TRANSITION METAL CATALYST COMPOSITION CONTAINING SAME, AND METHOD FOR PRODUCING ETHYLENE / α-OLEFIN COPOLYMER USING SAME

Abstract

To provide a novel transition metal compound, a transition metal catalyst composition having high catalytic activity for producing a copolymer of ethylene and α-olefin containing the same, a method for producing a copolymer of ethylene and α-olefin using the same, and a copolymer of ethylene and α-olefin produced.SOLUTION: Fer example, a transition metal compound having the structure of the formula 1 in the figure is presented.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a novel transition metal compound, a transition metal catalyst composition containing the same for producing an ethylene / α-olefin copolymer, a method for producing an ethylene / α-olefin copolymer using the same, and an ethylene / α-olefin copolymer produced using the transition metal compound as a catalyst. [Background technology]

[0002] Conventionally, the production of ethylene homopolymers and copolymers of ethylene and α-olefins has generally been achieved using the so-called Ziegler-Natta catalyst system, which consists of a titanium or vanadium compound as the main catalyst component and an alkylaluminum compound as the cocatalyst component. Although the Ziegler-Natta catalyst system exhibits high activity in ethylene polymerization, the polymers generally produced have a wide molecular weight distribution due to the heterogeneous catalytic active sites, and the composition distribution is not uniform, especially in the case of copolymers of ethylene and α-olefins.

[0003] Since then, various studies have been conducted on metallocene catalyst systems consisting of metallocene compounds of transition metals in the periodic table, such as zirconium and hafnium, and methylaluminoxane as a cocatalyst, which can produce polyethylene with narrower molecular weight distribution and more uniform composition distribution than conventional Ziegler-Natta catalyst systems as homogeneous catalysts with a single type of catalytic active site. The metallocene compounds are currently being actively used industrially as cyclopentadienyl-based catalysts with different substitution patterns, and are used not only for the production of polyethylene but also for polypropylene.

[0004] However, it is difficult to obtain a high molecular weight polymer using this catalyst system, since when it is applied to a solution polymerization method performed at high temperatures, the polymerization activity decreases rapidly and the β-dehydrogenation reaction predominates, making it unsuitable for producing a high molecular weight polymer.

[0005] A transition metal catalyst in which transition metals are linked in a ring has been announced as a catalyst that has high catalytic activity and can produce high molecular weight polymers in the homopolymerization of ethylene or the copolymerization of ethylene with α-olefins under solution polymerization conditions.

[0006] US6313240 describes a catalyst system comprising a hafnium organometallic compound having a cyclopentadienyl ligand or an aromatic fused and substituted cyclopentadienyl ligand; an aromatic fused and substituted cyclopentadienyl ligand; and a bridge connecting the two cyclopentadienyl ligands.

[0007] US6559253 discloses an example of a structure in which an unsubstituted fluorene is linked to a diphenyl-substituted bridge and one cyclopentadiene ligand, and US6300433 discloses a structure in which one or more substituted cyclopentadienyl-fluorenyl ligands have a substituted diphenylmethylene bridge.

[0008] In the case of such catalysts, the reactivity with α-olefins has been significantly improved due to the reduced steric hindrance effect of the catalyst itself, but there are many difficulties in using them commercially. Therefore, it is important to secure a more competitive catalyst system that meets the required characteristics of a commercial catalyst based on economic efficiency, i.e., excellent high-temperature activity, excellent reactivity with α-olefins, and the ability to produce polymers with high molecular weights. Summary of the Invention [Problem to be solved by the invention]

[0009] One embodiment of the present invention is to provide novel transition metal compounds. Another embodiment of the present invention is to provide a transition metal catalyst composition comprising said transition metal compound capable of producing high molecular weight copolymers of ethylene and α-olefins.

[0010] Yet another embodiment of the present invention provides an industrially economical and easy-to-use process for producing copolymers of ethylene and α-olefins using a catalyst composition containing the transition metal compound. [Means for solving the problem]

[0011] In order to achieve the above-mentioned object, the present inventors have conducted research and found that by stabilizing the active sites of a compound used as a catalyst, a high molecular weight copolymer of ethylene and an α-olefin can be produced by high-temperature solution polymerization, thereby completing the present invention.

[0012] The present invention provides a transition metal compound represented by the following chemical formula 1:

[0013] [Chemical formula 1] TIFF0007681063000001.tif29170

[0014] [In the above Chemical Formula 1, M is a group 4 transition metal; R 1 and R 2 are each independently (C6-C20)aryl(C1-C20)alkyl unsubstituted or substituted with (C1-C10)alkyl; R 3 and R 4 are each independently (C6-C20)aryl unsubstituted or substituted with (C1-C10)alkyl; X 1 and X 2 are each independently halogen, (C1-C20)alkyl, (C3-C20)cycloalkyl, (C6-C20)aryl, (C6-C20)aryl(C1-C20)alkyl, ((C1-C20)alkyl(C6-C20)aryl)(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryloxy, (C1-C20)alkyl(C6-C20)aryloxy, (C1-C20)alkoxy(C6-C20)aryloxy, -OSiR a R b Rc , -SR d , -NR e R f , -PR g R h or (C1-C20) alkylidene; R a ~R d are each independently (C1-C20)alkyl, (C6-C20)aryl, (C6-C20)aryl(C1-C20)alkyl, (C1-C20)alkyl(C6-C20)aryl, or (C3-C20)cycloalkyl; R e ~R h are each independently (C1-C20)alkyl, (C6-C20)aryl, (C6-C20)aryl(C1-C20)alkyl, (C1-C20)alkyl(C6-C20)aryl, (C3-C20)cycloalkyl, tri(C1-C20)alkylsilyl, or tri(C6-C20)arylsilyl; X 1 or X 2 When one of is (C1-C20)alkylidene, the other is absent.

[0015] In detail, M in the above formula 1 is Ti, Zr, or Hf, and R 1 and R 2 are each independently (C6-C20)aryl(C1-C20)alkyl; R 3 and R 4 are each independently unsubstituted or (C-C) alkyl-substituted (C-C) aryl; 1 and X 2 may each independently be halogen, (C1-C20)alkyl, (C6-C20)aryl, or (C6-C20)aryl(C1-C20)alkyl.

[0016] In addition, M in the above formula 1 is Hf, and R 1 and R 2 are each independently (C6-C12)aryl(C1-C10)alkyl; R 3and R 4 are each independently (C6-C12)aryl; X 1 and X 2 may each independently be halogen, (C1-C10)alkyl, (C6-C12)aryl, or (C6-C12)aryl(C1-C10)alkyl.

[0017] More specifically, in one embodiment of the present invention, M in Formula 1 is Hf, and R 3 and R 4 is phenyl, and X 1 and X 2 are each independently methyl, benzyl, or Cl; R 1 and R 2 may each independently be represented by the following chemical formula 2:

[0018] [Chemical formula 2] TIFF0007681063000002.tif13170

[0019] [In the above Chemical Formula 2, L is a linear or branched (C1-C10) alkylene.

[0020] The transition metal compound according to an embodiment of the present invention may be [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dichloro, [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dibenzyl, or [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dimethyl.

[0021] The present invention provides a transition metal catalyst composition for producing an ethylene / α-olefin copolymer, comprising a transition metal compound according to one embodiment of the present invention and a cocatalyst selected from an aluminum compound, a boron compound, or a mixture thereof.

[0022] The aluminum compound used as the co-catalyst may be one or more selected from aluminoxanes and organoaluminums. The present invention also provides a method for producing a copolymer of ethylene and an α-olefin, which may include the steps of: a) mixing the transition metal catalyst composition according to one embodiment of the present invention, ethylene, and an α-olefin comonomer; and b) conducting a copolymerization reaction at a temperature of 110 to 170°C.

[0023] The α-olefin copolymerized with ethylene may be 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, 1-eicosene, cyclopentene, cyclohexene, norbornene, phenylnorbornene, styrene, α-methylstyrene, p-methylstyrene, and 3-chloromethylstyrene.

[0024] Specifically, the b) step may be carried out at a temperature of 120° C. to 160° C. and a pressure of 10 to 100 bar. The method for producing the copolymer of ethylene and an α-olefin may also be carried out in a C5-C12 aliphatic hydrocarbon solvent.

[0025] The present invention provides an ethylene / α-olefin copolymer produced using a transition metal compound according to one embodiment of the present invention as a catalyst. Effect of the Invention

[0026] The novel transition metal compound of the present invention can be easily produced in high yields through simple processes under mild conditions, and the transition metal compound, which is a single active site catalyst, and the catalyst composition containing the same have excellent thermal stability and can maintain excellent catalytic activity even at high temperatures. Therefore, by using the transition metal compound, a high molecular weight copolymer of ethylene and an α-olefin can be produced. The method for producing such an ethylene and an α-olefin copolymer is a very economical method since it is possible to obtain copolymers having various physical properties in high yields through simple processes, and can be easily used for industrial mass production. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The novel transition metal compound of the present invention, the transition metal catalyst composition containing the same, and the process for producing an ethylene / α-olefin copolymer using the same will be described in detail below.

[0028] As used herein, the singular forms may be intended to include the plural forms as well, unless the context indicates otherwise. The term "comprising" as used herein is an open-ended term having the same meaning as terms such as "comprising," "containing," "having," or "characterized by," and does not exclude additional, unrecited elements, materials, or steps.

[0029] As used herein, "alkyl" refers to a monovalent linear or branched saturated hydrocarbon group consisting only of carbon and hydrogen atoms; examples of such alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, hexyl, octyl, nonyl, and the like.

[0030] The "aryl" described in the present invention is an organic group derived by removing one hydrogen atom from an aromatic hydrocarbon, and includes a single ring or a fused ring system, each ring suitably containing 4 to 7, preferably 5 or 6, ring atoms, and includes a form in which multiple aryls are linked by a single bond. The fused ring system may include an aliphatic ring, such as a saturated or partially saturated ring, and necessarily includes one or more aromatic rings. The aliphatic ring may also include nitrogen, oxygen, sulfur, carbonyl, etc. in the ring. Specific examples of the aryl group include, but are not limited to, phenyl, naphthyl, biphenyl, indenyl, fluorenyl, phenanthrenyl, anthracenyl, triphenylenyl, pyrenyl, chrysenyl, naphthacenyl, 9,10-dihydroanthracenyl, etc.

[0031] As used herein, "cycloalkyl" refers to a monovalent saturated carbocyclic group consisting of one or more rings. Examples of cycloalkyl groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, etc.

[0032] By "halo" or "halogen" as used herein is meant a fluorine, chlorine, bromine, or iodine atom. The "alkoxy" described in the present invention is -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, where "alkyl" is defined above.

[0033] "Aryloxy" according to the present invention denotes the respective -O-aryl group, where "aryl" is as defined above. "Alkylidene" as described herein means a linear or branched saturated divalent hydrocarbon radical having a valence of two on a common carbon atom.

[0034] The present invention provides a transition metal compound represented by the following chemical formula 1:

[0035] [Chemical formula 1] TIFF0007681063000003.tif28170

[0036] [In the above Chemical Formula 1, M is a group 4 transition metal; R 1 and R 2 are each independently (C6-C20)aryl(C1-C20)alkyl unsubstituted or substituted with (C1-C10)alkyl; R 3 and R 4 are each independently (C6-C20)aryl unsubstituted or substituted with (C1-C10)alkyl; X 1 and X 2 are each independently halogen, (C1-C20)alkyl, (C3-C20)cycloalkyl, (C6-C20)aryl, (C6-C20)aryl(C1-C20)alkyl, ((C1-C20)alkyl(C6-C20)aryl)(C1-C20)alkyl, (C1-C20)alkoxy, (C6-C20)aryloxy, (C1-C20)alkyl(C6-C20)aryloxy, (C1-C20)alkoxy(C6-C20)aryloxy, -OSiR a R b R c , -SR d , -NR e R f , -PR g R h or (C1-C20) alkylidene; Ra ~R d are each independently (C1-C20)alkyl, (C6-C20)aryl, (C6-C20)aryl(C1-C20)alkyl, (C1-C20)alkyl(C6-C20)aryl, or (C3-C20)cycloalkyl; R e ~R h are each independently (C1-C20)alkyl, (C6-C20)aryl, (C6-C20)aryl(C1-C20)alkyl, (C1-C20)alkyl(C6-C20)aryl, (C3-C20)cycloalkyl, tri(C1-C20)alkylsilyl, or tri(C6-C20)arylsilyl; X 1 or X 2 When one of is (C1-C20)alkylidene, the other is absent.

[0037] The transition metal compound represented by Chemical Formula 1 is a compound having a structure in which a transition metal of Group 4 of the periodic table as a central metal is linked by a cyclopentadienyl group that is rich in electrons and widely delocalized, and a fluorenyl group substituted with an aryl alkyl group at the 2- and 7-positions, and the cyclopentadienyl group and the fluorenyl group are linked by carbon, and the catalytic active site can be stabilized by the fluorenyl group substituted with an aryl alkyl group at the 2- and 7-positions, so that the compound can exhibit excellent catalytic activity in ethylene homopolymerization or copolymerization of ethylene and α-olefin. Furthermore, when the transition metal compound is used in a solution polymerization process performed at high temperature, an ethylene homopolymer or a copolymer of ethylene and α-olefin having a high molecular weight can be produced.

[0038] In detail, M in the above formula 1 is Ti, Zr, or Hf, and R 1 and R 2 are each independently (C6-C20)aryl(C1-C20)alkyl; R 3 and R 4 are each independently unsubstituted or (C-C) alkyl-substituted (C-C) aryl;1 and X 2 may each independently be halogen, (C1-C20)alkyl, (C6-C20)aryl, or (C6-C20)aryl(C1-C20)alkyl.

[0039] In one embodiment, M in Formula 1 is Hf; R 1 and R 2 are each independently (C6-C12)aryl(C1-C10)alkyl; R 3 and R 4 are each independently (C6-C12)aryl; X 1 and X 2 may each independently be halogen, (C1-C10)alkyl, (C6-C12)aryl, or (C6-C12)aryl(C1-C10)alkyl.

[0040] In addition, in one embodiment, M in Formula 1 is Hf, and R 1 and R 2 are each independently (C6-C12)aryl(C1-C5)alkyl; R 3 and R 4 are each independently (C6-C12)aryl; X 1 and X 2 may each independently be halogen, (C1-C5)alkyl, (C6-C12)aryl, or (C6-C12)aryl(C1-C5)alkyl.

[0041] More specifically, in one embodiment of the present invention, M in Formula 1 is Hf, and R 3 and R 4 is phenyl, and X 1 and X 2 are each independently methyl, benzyl, or Cl; R 1 and R 2 may each independently be represented by the following chemical formula 2:

[0042] [Chemical formula 2] TIFF0007681063000004.tif13170

[0043] [In the above Chemical Formula 2, L is a linear or branched (C1-C10) alkylene.

[0044] More specifically, L in the above formula 2 may be a linear or branched (C1-C5) alkylene. The transition metal compound according to an embodiment of the present invention may be [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dichloro, [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dibenzyl, or [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dimethyl.

[0045] Meanwhile, the transition metal compound according to one embodiment of the present invention is an active catalyst component used in the preparation of ethylene and α-olefin copolymers, so that X of the transition metal compound of the formula 1 is preferably 1 and X 2 Aluminum compounds, boron compounds, or mixtures thereof that can act as weakly binding counterions, i.e., anions, while abstracting ligands to cationize the metal center, can act together as promoters.

[0046] Accordingly, the present invention provides a transition metal catalyst composition for producing copolymers of ethylene and α-olefins, comprising a transition metal compound according to one embodiment of the present invention and a cocatalyst selected from an aluminum compound, a boron compound, or a mixture thereof.

[0047] In the transition metal catalyst composition for producing an ethylene-α-olefin copolymer according to one embodiment of the present invention, the aluminum compound used as the co-catalyst may be one or more selected from aluminoxane, organoaluminum, and organoaluminum oxide compounds, and the aluminum compound may be one or more selected from aluminoxane compounds represented by the following Chemical Formula 3 or 4, organoaluminum compounds represented by the following Chemical Formula 5, or organoaluminum oxide compounds represented by the following Chemical Formula 6 or 7.

[0048] [Chemical formula 3] (-Al(R 11 )-O-) m

[0049] [Chemical formula 4] (R 11 ) 2 Al-(-O(R 11 )-) q -(R 11 ) 2

[0050] [Chemical formula 5] (R 12 ) r Al(E) 3-r

[0051] [Chemical formula 6] (R 13 ) 2 AlOR 14

[0052] [Chemical formula 7] R 13 Al(OR 14 ) 2

[0053] [In the above chemical formulas 3 to 7, R 11 is (C1-C20) alkyl; R 12 and R 13 are each (C1-C20) alkyl; E is hydrogen or halogen; R 14 is (C1-C20) alkyl or (C6-C20) aryl; m and q are each an integer of 5 to 20; and r is an integer from 1 to 3.

[0054] Specifically, R in Formulas 3 and 4 11 may be methyl or isobutyl. Specific examples of the aluminum compound that can be used include aluminoxane compounds such as methylaluminoxane, modified methylaluminoxane, and tetraisobutylaluminoxane. Examples of organoaluminum compounds include trialkylaluminums such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, trihexylaluminum, and trioctylaluminum, dialkylaluminum chlorides such as dimethylaluminum chloride, diethylaluminum chloride, dipropylaluminum chloride, diisobutylaluminum chloride, and dihexylaluminum chloride, alkylaluminum dichlorides such as methylaluminum dichloride, ethylaluminum dichloride, propylaluminum dichloride, isobutylaluminum dichloride, and hexylaluminum dichloride, and dialkylaluminum hydrides such as dimethylaluminum hydride, diethylaluminum hydride, dipropylaluminum hydride, diisobutylaluminum hydride, and dihexylaluminum hydride.

[0055] More preferably, the aluminum compound may be one or more selected from methylaluminoxane, modified methylaluminoxane, tetraisobutylaluminoxane, trimethylaluminum, triethylaluminum, trioctylaluminum, and triisobutylaluminum.

[0056] The boron compound usable as the promoter in the present invention may be selected from the boron compounds represented by the following chemical formulas 8 to 10.

[0057] [Chemical formula 8] B(R 21 ) 3

[0058] [Chemical formula 9] [R 22 ] + [B(R 21 ) 4 ] -

[0059] [Chemical formula 10] [(R 23 ) p ZH] + [B(R 21 ) 4 ] -

[0060] [In the above chemical formulas 8 to 10, B is a boron atom; Z is a nitrogen or phosphorus atom; R 21 is phenyl, The phenyl may be further substituted with 3 to 5 substituents selected from fluoro, fluoro-substituted or unsubstituted (C1-C20) alkyl, and fluoro-substituted or unsubstituted (C1-C20) alkoxy; R 22 is a (C5-C7)aryl group, a (C1-C20)alkyl(C6-C20)aryl group, or a (C6-C20)aryl(C1-C20)alkyl group; R 23 is an anilinium group substituted with a (C1-C50) alkyl group or two (C1-C10) alkyl groups together with the nitrogen atom, p is an integer of 2 or 3.

[0061] More specifically, R 22may be a triphenylmethylium group. Preferably, the boron compound used as the promoter may be one or more selected from dimethylphenylammonium tetraphenylborate, trityl tetraphenylborate, dimethylphenylammonium tetrakis(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, pyridinium tetrakis(pentafluorophenyl)borate, and silver tetrakis(pentafluorophenyl)borate.

[0062] Meanwhile, the co-catalyst may act as a scavenger to remove impurities in the reactants that act as poisons to the catalyst. In one embodiment of the present invention, when the aluminum compound and the boron compound are used as co-catalysts, the ratio of the transition metal compound of the present invention to the co-catalyst may be preferably in the range of 1:(10-3,000):(1-100) as a molar ratio of transition metal (M):aluminum atom (Al):boron atom (B), more preferably in the range of 1:(100-1,000):(3-10).

[0063] When the ratio of the transition metal compound to the co-catalyst of the present invention is within the above range, the transition metal compound can be sufficiently activated, thereby making it possible to obtain excellent catalytic activity of the transition metal compound; however, the range of the ratio is not limited thereto, and can vary depending on the reaction conditions and purpose.

[0064] The present invention provides a method for producing a copolymer of ethylene and an α-olefin, which may include the steps of: a) mixing a transition metal catalyst composition according to one embodiment of the present invention, ethylene, and an α-olefin comonomer; and b) conducting a copolymerization reaction at a temperature of 110 to 170°C.

[0065] The present invention also provides a method for producing an ethylene homopolymer in addition to the above-mentioned copolymer, and the copolymer may be produced in a similar manner using only ethylene instead of the comonomer.

[0066] Specifically, the b) step may be carried out at a temperature of 120 to 165° C. and a pressure of 10 to 100 bar, preferably at a temperature of 130 to 160° C. and a pressure of 15 to 50 bar.

[0067] In the method for producing a copolymer of ethylene and an α-olefin according to one embodiment of the present invention, the α-olefin may be one or more selected from the group consisting of (C3-C18) α-olefins, (C5-C20) cycloolefins, styrene and derivatives thereof. Examples of the (C3-C18) α-olefins include propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1- Examples of the (C5-C20) cycloolefin may be one or more selected from the group consisting of cyclopentene, cyclohexene, norbornene, and phenylnorbornene, and examples of styrene and its derivatives may be one or more selected from styrene, α-methylstyrene, p-methylstyrene, and 3-chloromethylstyrene. More specifically, the α-olefin may be one or more selected from 1-butene, 1-hexene, 1-octene, and 1-decene, but is not limited thereto.

[0068] The method for producing an ethylene homopolymer or an ethylene and α-olefin copolymer using the transition metal catalyst composition according to one embodiment of the present invention may be carried out by contacting the transition metal catalyst, the cocatalyst, the α-olefin comonomer, and ethylene in the presence of a suitable organic solvent. In this case, the transition metal catalyst, the cocatalyst, and the α-olefin comonomer components may be separately charged into a reactor, or each component may be mixed in advance and then charged into the reactor.

[0069] The preparation method may also be carried out in a C5-C12 aliphatic hydrocarbon solvent, specifically, the C5-C12 aliphatic hydrocarbon solvent may be one or more selected from butane, isobutane, pentane, hexane, heptane, octane, isooctane, nonane, decane, dodecane, cyclohexane, and methylcyclohexane, and preferably hexane, cyclohexane, or a mixture thereof.

[0070] The method for producing an ethylene / α-olefin copolymer according to one embodiment of the present invention does not use toluene, which is a co-solvent commonly used in the production of copolymers, and therefore reduces the step of removing the toluene solvent in the production process, making it a more economical production method.

[0071] The present invention provides an ethylene homopolymer or a copolymer of ethylene and an α-olefin produced by using a transition metal catalyst composition according to one embodiment of the present invention, and the produced homopolymer or copolymer can be easily produced very economically from an elastomer to a high density polyethylene (HDPE) region having a density of 0.850 g / mL to 0.910 g / mL and a melt flow rate of 0.001 to 20 g / 10 min.

[0072] In addition, hydrogen may be used as a molecular weight regulator to regulate the molecular weight during the preparation of the ethylene homopolymer or ethylene and α-olefin copolymer according to the present invention, and the weight average molecular weight of the homopolymer or copolymer produced may be 5,000 to 1,000,000 g / mol, specifically 10,000 to 800,000 g / mol, more specifically 30,000 to 500,000 g / mol.

[0073] The catalyst composition according to one embodiment of the present invention is very suitable for high-temperature solution polymerization processes since it can maintain a uniform morphology in a polymerization reactor, but it can also be applied to a slurry polymerization process or a gas phase polymerization process in the form of a heterogeneous catalyst obtained by supporting the catalyst or a composition containing the catalyst on a porous metal oxide support.

[0074] The present invention provides a high molecular weight ethylene homopolymer or copolymer of ethylene and an α-olefin produced using a transition metal compound as a catalyst according to one embodiment.

[0075] The novel transition metal compound according to the present invention, the transition metal catalyst composition containing the same, and the method for producing an ethylene / α-olefin copolymer using the same will be described in more detail below with reference to specific examples.

[0076] All of the following synthetic reactions were carried out under an inert atmosphere such as nitrogen or argon, and standard Schlenk and glove box techniques were utilized.

[0077] In addition, tetrahydrofuran (THF), n-hexane, n-pentane, diethyl ether, methylene chloride (CH 2 Cl 2 Solvents for synthesis such as ethyl acetate were passed through an activated alumina column to remove moisture and then stored on activated molecular sieves. Most of the reagents were purchased from Sigma-Aldrich, TCI, Alfa, and Strem unless otherwise stated.

[0078] 1H NMR analysis of the synthesized compounds was carried out at room temperature using a Bruker 500 MHz. The molecular weight and copolymerization properties of the ethylene homopolymer or ethylene-α-olefin copolymer were analyzed by the following methods.

[0079] MFR analysis was performed by melting the plastic at 190℃ and measuring the weight of the extrudate flowing through a specified capillary tube (Orifice) for 10 minutes at loads of 2.16, 5, and 21.6 kg. It was expressed as Melt Index (MI) (g / 10 min) according to the ASTM D1238 measurement standard. If the MI is low, the molecular weight increases and the fluidity decreases, so the processability decreases and the physical properties improve.

[0080] GPC analysis, which concerns the molecular weight average (Mw, Mn) of the polymers and their width as described by molecular weight distribution (MWD), was performed by high temperature size exclusion chromatography (HTSEC) on a Polymer Laboratories PLXT-20 high speed GPC polymer analysis system (including pump, refractive index detector, and viscosity detector) with 3PLgel Olexis columns (300 x 7.5 mm, Polymer Laboratories) connected in series at 160 °C. 1,2,4-trichlorobenzene containing butylated hydroxytoluene (0.5 g / L) and Irganox 1010 (20 mg / L) was used as eluent at a flow rate of 1.0 mL / min. Molecular weights were calculated based on polyethylene standards (Mp = 5,310-1,510,000 g / mol, Polymer Laboratories). A Polymer Laboratories PL XT-220 robotic sample handling system was used as the autosampler. The concentrations of the samples were analyzed to be 2-4 mg polymer / mL TCB.

[0081] The density is in the range of 0.850 to 0.910 g / mL, and the closer the density is to 0.85, the higher the copolymerization. To measure the density, the weight of the resin per unit volume was measured. The analysis was performed according to the ASTM D1505 (KS M3016) measurement standard using the density gradient method, which creates a calibration curve for the density of a standard column and the column height.

[0082] Temperature-controlled DSC experiments were performed on a TA Instruments Q2000 DSC operated in modulated mode according to ISO 11357-1 and calibrated with indium, tin, and zinc. Five milligrams of sample were placed in an aluminum pan and heated to an initial temperature of 180°C, then cooled to -88°C at 10°C / min as in standard DSC. The temperature was then increased at a heating rate of 2°C / min with a temperature control of 0.32°C every 60 seconds. The glass transition temperature was measured from the reversible heat flow thermogram, which shows the inversion point of the transition. The higher the copolymerization, the lower the Tm measured.

[0083] [Production Example 1] [Production of 1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-(2-phenylpropanyl)-fluorenyl)-1,1-diphenylmethane]hafnium dichloro (Compound 1)

[0084] Step 1: Preparation of 2,7-dibenzoyl-fluorene (compound 1-a) TIFF0007681063000005.tif21170

[0085] In a Schlenk flask, add AlCl 3 (17.6 g, 132.3 mmol), DCM (120 mL), and fluorene (10 g, 60.2 mmol) were added, and benzoyl chloride (13.9 mL, 120.4 mmol) was added at 0 °C, followed by stirring at room temperature for 18 hours. Ice and water were gradually added to terminate the reaction, and then DCM was added for extraction. The organic layer was collected and diluted with MgSO 4 After drying at 40° C., filtration under reduced pressure, and recrystallization from ether / Hex gave yellow solid compound 1-a (20 g, 91% yield).

[0086] 1H NMR(500MHz,Chloroform-d)δ7.90(s,2H),7.88(d,J=7.7Hz,2H),7.85(d,J=7.5Hz,2H)7.83(m,4H),7.60(d,J=7.7Hz,2H),7.50(m,4H),4.05(s,2H)

[0087] Step 2: Preparation of 2,7-di-(2-phenylpropan-2-yl)-fluorene (compound 1-b) TIFF0007681063000006.tif21170

[0088] Compound 1-a (8.2 g, 22 mmol), toluene (109 mL), and acetic acid (0.3 mL, 5.47 mmol) were placed in a Schlenk flask, followed by the addition of trimethylaluminum (109 mL, 219 mmol, 2.0 M in Hex), and the mixture was refluxed at 100°C for 6 hours. The reaction was terminated by adding 1N HCl and ice, and the mixture was extracted three times with ether. The organic layer was collected and diluted with MgSO4 After drying at 40° C. and filtering under reduced pressure, the mixture was purified on a silica column (solvent: Hex) to obtain a yellow solid compound 1-b (8.5 g, yield: 96%).

[0089] 1H NMR (500MHz, Chloroform-d) δ7.61(d,J=7.7Hz,2H),7.38(s,2H),7.23(m,8H),7.21(m,2H),7.17(m,2H),3.78(s,2H),1.72(s,12H).

[0090] Step 3: Preparation of 1-(2,4-cyclopentadien-1-yl)-1-(2,7-di-(2-phenylpropan-2-yl)-fluorenyl)-1,1-diphenylmethane (compound 1-c) TIFF0007681063000007.tif33170

[0091] Compound 1-b (12 g, 43.1 mmol) was dissolved in 87 mL of THF, and nBuLi (1.6 M in Hex, 27.1 mL, 43.1 mmol) was added and stirred at room temperature for 3 hours. 6,6-Diphenylfulvene (10 g, 43.1 mmol) was added, and the reaction solution was stirred for 16 hours, and then NH 4 The reaction was quenched by adding aqueous Cl (40 mL). The product was extracted into the organic layer and diluted with MgSO 4 After drying at 40° C., filtration under reduced pressure, the resulting yellow solid was washed with ethanol to obtain white solid compound 1-c (24 g, yield 94%).

[0092] 1H NMR (500MHz, Chloroform-d) δ7.02~7.30 (m, 28H), 6.21 (s, 2H), 5.41 (s, 1H), 2.83 (br s, 1H), 1.53 (s, 12H).

[0093] Step 4: Preparation of [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)-fluorenyl)-1,1-diphenylmethane]hafnium dichloro (compound 1) TIFF0007681063000008.tif33170

[0094] Compound 1-c (2.5 g, 3.95 mmol) was dissolved in 39 mL of ether, and nBuLi (1.6 M in Hex, 5.43 mL, 8.69 mmol) was added and stirred for 16 hours. After removing the ether by vacuum drying, Hex was added and decanted, and the pressure was reduced. In a glove box, lithium (2.5 g, 3.89 mmol) and HfCl 4 (1.24g, 3.89mmol) was weighed and dissolved in 35mL of ether, stirred at room temperature for 16 hours, and then vacuum dried to remove the ether. 80mL of toluene was added and heated at 50℃ for 2 hours, after which the resulting LiCl was precipitated and filtered. The filtrate was vacuum dried and crystallized to obtain yellow crystalline compound 1 (2.4g, 71% yield).

[0095] 1H NMR(500MHz,Chloroform-d)δ7.94(d,J=9.5Hz,2H),7.80(d,J=7.4Hz,2H),7.71(d,J=7.5Hz,2H),7. 05~7.34(m,18H),6.28(t,J=7.5Hz,2H),6.19(s,2H),5.28(t,J=7.4Hz,2H),1.42(s,6H),1.38(s,6H)

[0096] [Comparative Production Example 1] [Synthesis of 1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenylmethane]hafnium dichloro (Compound 2)

[0097] [1-(η5-cyclopentadien-1-yl)-1-(η5-fluorenyl)-1,1-diphenylmethane]hafnium dichloro (compound 2) was synthesized according to the literature procedure [A. Razavi, JL Atwood, J. Organometallic. Chen, 459 (1993), 117-123].

[0098] 1H NMR(500MHz,Chloroform-d)δ8.19(d,J=8.5Hz,2H),7.95(d,J=8.3Hz,2H),7.88(d,J=8.5Hz,2H),7.55(t,J=8.0H z,2H),7.44(t,J=8.2Hz,2H),7.31(m,4H),7.01(t,J=8.1Hz,2H),6.47(d,J=7.1Hz,2H),6.33(s,2H),5.75(s,2H)

[0099] [Comparative Preparation Example 2] [Preparation of 1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-t-butylfluorenyl)-1,1-diphenylmethane]hafnium dichloro (Compound 3)

[0100] Step 1: Preparation of 1-(2,4-cyclopentadien-1-yl)-1-(2,7-di-t-butylfluorenyl)-1,1-diphenylmethane (compound 3-a) TIFF0007681063000009.tif34170

[0101] 2,7-Di-t-butylfluorene (12 g, 43.1 mmol) was dissolved in 87 mL of THF, and nBuLi (1.6 M in Hex, 27.1 mL, 43.1 mmol) was added and stirred at room temperature for 3 hours. 6,6-Diphenylfulvene (10 g, 43.1 mmol) was added and stirred for 16 hours, and then NH 4 The reaction was quenched by adding aqueous Cl (40 mL). The product was extracted into the organic layer and diluted with MgSO 4 After drying at 40° C., filtration under reduced pressure, the resulting yellow solid was washed with ethanol to give compound 3-a (20 g, yield 93%) as a white solid.

[0102] 1H NMR(500MHz,Chloroform-d)δ6.21~7.35(m,20H),5.45(s,1H),3.01(m,1H),1.14(s,18H)

[0103] Step 2: Preparation of [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-di-t-butylfluorenyl)-1,1-diphenylmethane]hafnium dichloro (compound 3) TIFF0007681063000010.tif33170

[0104] Compound 3-a (5 g, 9.82 mmol) was dissolved in 60 mL of ether, and nBuLi (1.6 M in Hex, 13.5 mL, 21.6 mmol) was added and stirred for 16 hours. After removing the ether by vacuum drying, Hex was added, decanted, and the pressure was reduced. In a glove box, lithium (5.1 g, 9.79 mmol) and HfCl 4 (3.13g, 9.79mmol) was weighed and dissolved in 80mL of ether, and then stirred at room temperature for 16 hours. After removing the ether by vacuum drying, 80mL of toluene was added and heated at 50℃ for 2 hours to precipitate the LiCl produced, which was then filtered. The filtrate was dried in vacuum and crystallized to obtain yellow crystalline compound 3 (4.4g, 60% yield).

[0105] 1H NMR(500MHz,Chloroform-d)δ8.03(d,J=9.0Hz,2H),7.97(d,J=2.5Hz,2H),7.96(d,J=3.0Hz,2H),7.57(d,J=9.0Hz, 2H),7.45(m,2H),7.36(m,2H),7.29(m,2H),6.37(s,2H),6.29(t,J=2.5Hz,2H),5.63(t,J=3.0Hz,2H),1.04(s,18H)

[0106] [Comparative Preparation Example 3] [Preparation of 1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-diphenylfluorenyl)-1,1-diphenylmethane]hafnium dichloro (Compound 4)

[0107] Step 1: Preparation of 2,7-diphenylfluorene (compound 4-a) TIFF0007681063000011.tif21170

[0108] In a Schlenk flask, add Pd(PPh 3 ) 4 (1.8 g, 1.54 mmol) and 2,7-dibromo-9H-fluorene (5 g, 15.4 mmol) were added. After adding 100 mL of toluene, phenylboronic acid (7.5 g, 61.7 mmol) was added, and 50 mL of toluene and K 2 CO 3 Aqueous solution (30 mL, 2 M) was added. After refluxing at 100 °C for 16 h, the mixture was extracted three times with water and ether. The organic layer was collected and diluted with MgSO 4 After drying at 40° C. and filtering under reduced pressure, the mixture was purified on a silica column (Hex:Ethyl Acetate=10:1) to obtain compound 4-a (3.1 g, 63%) as a white solid.

[0109] 1H NMR(500MHz,Chloroform-d)δ7.87(d,J=7.7Hz,2H),7.79(s,2H),7.67(m,6H),7.46(m,4H),7.36(d,J=7.7Hz,2H),4.03(s,2H)

[0110] Step 2: Preparation of 1-(2,4-cyclopentadien-1-yl)-1-(2,7-diphenylfluorenyl)-1,1-diphenylmethane (compound 4-b) TIFF0007681063000012.tif33170

[0111] Compound 4-a (7 g, 21 mmol) was dissolved in 40 mL of THF, and nBuLi (1.6 M in Hex, 14 mL, 21 mmol) was added and stirred at room temperature for 3 hours. 6,6-Diphenylfulvene (5 g, 21 mmol) was added and stirred for 16 hours, and then NH 4 The reaction was quenched by adding aqueous Cl (20 mL). The product was extracted into the organic layer and diluted with MgSO 4 After drying at 40° C., filtration and decompression, the resulting yellow solid was washed with ethanol to obtain compound 4-b (20 g, yield 91%) as a white solid.

[0112] 1H NMR(500MHz,Chloroform-d)δ7.30~7.73(m,30H),5.61(s,1H),4.09(s,1H)

[0113] Step 3: Preparation of [1-(η5-cyclopentadien-1-yl)-1-(η5-2,7-diphenylfluorenyl)-1,1-diphenylmethane]hafnium dichloro (compound 4) TIFF0007681063000013.tif35170

[0114] Compound 4-b (5 g, 9.11 mmol) was dissolved in 60 mL of ether, and nBuLi (1.6 M in Hex, 13.5 mL, 21.6 mmol) was added and stirred for 16 hours. After removing the ether by vacuum drying, Hex was added and decanted, and the pressure was reduced. In a glove box, lithium (5.1 g, 9.11 mmol) and HfCl 4 (2.91g, 9.11mmol) was weighed and dissolved in 80mL of ether. After stirring at room temperature for 16 hours, the ether was removed by vacuum drying, and then 80mL of toluene was added and heated at 50℃ for 2 hours, after which the generated LiCl was precipitated and filtered. The filtrate was dried in vacuum and crystallized to obtain yellow crystalline compound 4 (10g, yield 67%).

[0115] 1H NMR(500MHz,Chloroform-d)δ8.23(d,J=9.0Hz,2H),7.96(d,J=2.5Hz,2H),7.94(d,J=3.0 Hz,2H),7.78(d,J=9.0Hz,2H),7.27~7.48(m,16H),6.60(s,2H),6.28(s,2H),5.74(s,2H)

[0116] [Example 1] Production of ethylene and α-olefin copolymer At room temperature, 1L of Hex and triisobutylaluminum (1M, 2mL) were added to a 4L reactor, followed by the addition of 1-octene (100mL). In a glove box, Preparation Example 1 (compound 1) (3.9μmol) was dissolved in triisobutylaluminum (0.1M in Hex, 2mL), and then 5mL of hexane was added and injected into the inlet of the reactor. In a glove box, trityltetrakis(pentafluorophenyl)borate (19.5μmol) was dissolved in 5mL of Hex and added to the inlet. After the reactor was heated to 140°C, the solution in the inlet was added with high-pressure nitrogen. Ethylene was injected at 300psig for 15 minutes, and it can be seen that the initial temperature increases in proportion to the activity. After the polymerization reaction was completed, the temperature of the reactor was cooled to 30°C, and the ethylene pressure inside the reactor was gradually vented and removed. The polymer produced was washed with ethanol and acetone, filtered and vacuum dried. The results of the produced polymer are shown in Table 1.

[0117] [Example 2] The same procedure as in Example 1 was carried out, except that anilinium tetrakis(pentafluorophenyl)borate was used instead of trityl tetrakis(pentafluorophenyl)borate, and the results are shown in Table 1.

[0118] [Example 3] The same procedure as in Example 1 was carried out, except that the reaction temperature was 150° C. instead of 140° C., and the results are shown in Table 1.

[0119] [Example 4] The same procedure as in Example 1 was carried out, except that the reaction temperature was 150° C. instead of 140° C., and anilinium tetrakis(pentafluorophenyl)borate was used instead of trityl tetrakis(pentafluorophenyl)borate, and the results are shown in Table 1.

[0120] [Comparative Example 1] The same procedure as in Example 1 was carried out, except that Compound 2 (Comparative Preparation 1) was used instead of Compound 1 (Preparation 1) in Example 1. The results are shown in Table 1.

[0121] [Comparative Example 2] The same procedure as in Example 1 was repeated, except that Compound 2 (Comparative Preparation 1) was used instead of Compound 1 (Preparation Example 1) and anilinium tetrakis(pentafluorophenyl)borate was used instead of trityl tetrakis(pentafluorophenyl)borate, and the results are shown in Table 1.

[0122] [Comparative Example 3] The same procedure as in Example 1 was carried out, except that Compound 3 (Comparative Preparation 2) was used instead of Compound 1 (Preparation 1) in Example 1, and the results are shown in Table 1.

[0123] [Comparative Example 4] The same procedure as in Example 1 was repeated, except that Compound 3 (Comparative Preparation 2) was used instead of Compound 1 (Preparation 1) and anilinium tetrakis(pentafluorophenyl)borate was used instead of trityl tetrakis(pentafluorophenyl)borate, and the results are shown in Table 1.

[0124] [Comparative Example 5] The same procedure as in Example 1 was repeated, except that Compound 3 (Comparative Preparation 2) was used instead of Compound 1 (Preparation 1) and the reaction temperature was 150° C. instead of 140° C., and the results are shown in Table 1.

[0125] [Comparative Example 6] The same procedure as in Example 1 was repeated, except that Compound 3 (Comparative Preparation 2) was used instead of Compound 1 (Preparation Example 1), anilinium tetrakis(pentafluorophenyl)borate was used instead of trityl tetrakis(pentafluorophenyl)borate, and the reaction temperature was 150°C instead of 140°C. The results are shown in Table 1.

[0126] [Comparative Example 7] The same procedure as in Example 1 was carried out, except that Compound 4 (Comparative Preparation 3) was used instead of Compound 1 (Preparation 1) in Example 1, and the results are shown in Table 1.

[0127] [Comparative Example 8] The same procedure as in Example 1 was repeated, except that Compound 4 (Comparative Preparation 3) was used instead of Compound 1 (Preparation Example 1) and anilinium tetrakis(pentafluorophenyl)borate was used instead of trityl tetrakis(pentafluorophenyl)borate, and the results are shown in Table 1.

[0128] The results of DSC and GPC analysis of the copolymers of Example 1, Comparative Example 1, Comparative Example 3, and Comparative Example 7 using the same temperature and cocatalyst are shown in Table 2 below.

[0129] [Table 1]

[0130] [Table 2]

[0131] As shown in Table 1, in the production of ethylene and 1-octene copolymers, Examples 1 to 4 of the present invention show superior catalytic activity compared to the comparative examples under the same conditions in which the compounds were changed.

[0132] Furthermore, as shown in Table 2, when comparing the ethylene and 1-octene copolymers of Example 1, Comparative Example 1, Comparative Example 3, and Comparative Example 7 produced under the same conditions, Example 1 of the present invention exhibited a weight average molecular weight that was 1.3 to 2.0 times higher and a number average molecular weight that was 1.6 to 2.2 times higher, indicating that a polymer having a very high molecular weight can be produced when the transition metal compound of the present invention is used as a catalyst.

[0133] Similarly, Example 1 of the present invention shows a lower Tm result than Comparative Examples 1, 3, and 7. As described above, the more excellent the copolymerizability, the lower the Tm, and therefore it can be seen that the transition metal compound of the present invention has excellent copolymerizability when used as a catalyst.

[0134] The transition metal compound of the present invention has a structure in which a Group 4 transition metal of the periodic table as a central metal is linked by a cyclopentadienyl group that is electron-rich and widely delocalized, and a fluorenyl group in which arylalkyl is substituted at the 2- and 7-positions, which can stabilize the active site, and therefore can exhibit excellent catalytic activity and high molecular weight in the high-temperature solution polymerization of ethylene and olefins.

[0135] Therefore, by utilizing the catalyst composition containing the transition metal compound of the present invention in the production of copolymers of ethylene and α-olefins, it is possible to produce copolymers with significantly improved molecular weights in high yields, and it is expected that it will be possible to mass-produce copolymers with excellent physical properties in an industrially very economical manner.

[0136] The present invention has been described above with specific details and limited examples and comparative examples, but these are merely provided for a more general understanding of the present invention, and the present invention is not limited to the above examples. A person having ordinary knowledge in the field to which the present invention belongs can make various modifications and variations from such descriptions.

[0137] Therefore, the spirit of the present invention should not be limited to the described embodiments, and all aspects that are equivalent or have equivalent modifications to the scope of the appended claims, as well as the scope of the present invention, are within the spirit of the present invention.

Claims

1. A transition metal compound represented by the following chemical formula 1, a cocatalyst selected from an aluminum compound, a boron compound, or a mixture thereof; A transition metal catalyst composition for producing a copolymer of ethylene and an α-olefin, comprising: [Chemical formula 1] [In the above Chemical Formula 1, M is Hf; R 1 and R 2 are each independently (C6-C12)aryl(C1-C10)alkyl; R 3 and R 4 are each independently (C6-C12)aryl; X 1 and X 2 are each independently halogen, (C1-C10) alkyl, (C6-C12) aryl, or (C6-C12) aryl(C1-C10) alkyl.

2. In the above formula 1, R 3 and R 4 are phenyl; X 1 and X 2 are each independently methyl, benzyl, or Cl; The transition metal catalyst composition for producing a copolymer of ethylene and an α-olefin according to claim 1, wherein R 1 and R 2 are each independently represented by the following chemical formula 2: [Chemical formula 2] [In the above Chemical Formula 2, L is a linear or branched (C1-C10) alkylene.

3. The transition metal catalyst composition for producing a copolymer of ethylene and an α-olefin according to claim 1, wherein the transition metal compound is [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dichloro, [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dibenzyl, or [1-(η5-cyclopentadiene-1-yl)-1-(η5-2,7-di-(2-phenylpropan-2-yl)fluorenyl)-1,1-diphenylmethane]hafnium dimethyl.

4. 2. The transition metal catalyst composition for producing an ethylene / α-olefin copolymer according to claim 1, wherein the aluminum compound used as the co-catalyst is one or more selected from aluminoxanes and organoaluminums.

5. a) mixing the transition metal catalyst composition for producing copolymers of ethylene and α-olefins according to claim 1, ethylene, and an α-olefin comonomer; b) carrying out a copolymerization reaction at a temperature of 110-170° C.; The present invention relates to a method for producing a copolymer of ethylene and an α-olefin, comprising the steps of:

6. The α-olefin copolymerized with the ethylene is one or more 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, 1-octadecene, 1-eicosene, cyclopentene, cyclohexene, norbornene, phenylnorbornene, styrene, α-methylstyrene, p-methylstyrene, and 3-chloromethylstyrene. The method for producing a copolymer of ethylene and α-olefin according to claim 5.

7. The method for producing an ethylene and α-olefin copolymer according to claim 5, wherein the step b) is carried out at a temperature of 120 to 160° C. and a pressure of 10 to 100 bar.

8. The method for producing an ethylene and α-olefin copolymer according to claim 5, wherein the method is carried out in a C5-C12 aliphatic hydrocarbon solvent.

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