CN113614124A

CN113614124A - Composite supported metallocene catalyst and method for preparing polyethylene copolymer by using same

Info

Publication number: CN113614124A
Application number: CN202080023435.1A
Authority: CN
Inventors: 金葡殷; 李承美; 权眩志; 李琪树; 权龙雨
Original assignee: LG Chem Ltd
Current assignee: LG Chem Ltd
Priority date: 2019-11-20
Filing date: 2020-11-20
Publication date: 2021-11-05
Anticipated expiration: 2040-11-20
Also published as: KR102564398B1; KR20210061954A; CN113614124B

Abstract

The present invention provides a composite supported metallocene catalyst that can be used to prepare a polyethylene copolymer exhibiting excellent process stability and high polymerization activity in ethylene polymerization, as well as excellent mechanical properties through high comonomer incorporation (comonomer incorporation).

Description

Composite supported metallocene catalyst and method for preparing polyethylene copolymer by using same

Technical Field

Cross Reference to Related Applications

The present application claims the benefit of korean patent application No. 10-2019-0149717, filed on 20.11.2019, and korean patent application No. 10-2020-0155726, filed on 19.11.2020, the disclosures of which are incorporated herein by reference in their entirety.

The invention relates to a composite supported metallocene catalyst and a method for preparing a polyethylene copolymer by using the same.

Background

Olefin polymerization catalyst systems can be classified into ziegler-natta catalysts and metallocene catalysts, and these high activity catalyst systems are developed according to their characteristics.

Ziegler-Natta catalysts have been widely used in commercial processes since the 1950 s development. However, since the Ziegler-Natta catalyst is a multi-active site catalyst in which a plurality of active sites are mixed, it is characterized in that the resulting polymer has a broad molecular weight distribution. Further, since the composition distribution of the comonomer is not uniform, there is a problem that it is difficult to obtain desired physical properties.

Meanwhile, the metallocene catalyst includes a main catalyst containing a transition metal compound as a main component and an organometallic compound co-catalyst containing aluminum as a main component. This catalyst is a single active site catalyst (which is a homogeneous complex catalyst) and provides a polymer with a narrow molecular weight distribution and a uniform comonomer composition distribution due to the single active site character. The stereoregularity, copolymerization characteristics, molecular weight, crystallinity, etc. of the resulting polymer can be controlled by varying the ligand structure of the catalyst and the polymerization conditions.

Recently, due to changes in environmental awareness, attempts have been made to reduce the production of Volatile Organic Compounds (VOCs) in many products. However, the Ziegler-Natta catalyst (Z/N) mainly used for preparing polyethylene has a problem of generating a large amount of VOC. In particular, various commercially available polyethylene products are mainly produced using ziegler-natta catalysts, but recently, the conversion to products produced using metallocene catalysts having low odor and low dissolution characteristics has been accelerated.

Meanwhile, Linear Low Density Polyethylene (LLDPE) is produced by copolymerizing ethylene and α -olefin using a polymerization catalyst at low pressure. However, there is a problem in that the comonomer concentration in the high molecular weight part of polyethylene is low due to the low comonomer incorporation property of the conventional catalyst itself, and thus it is difficult to improve the impact strength of the film. In particular, when the concentration of a comonomer such as an α -olefin is increased during copolymerization, there is a problem that the morphology of the produced polymer is deteriorated. In addition, the lower the density of LLDPE, the higher the impact strength of the film, but fouling often occurs during the production of low density polyethylene, deteriorating the process stability.

Therefore, there is a need for a catalyst for preparing low density polyethylene, which is capable of producing a low density polyethylene resin product having excellent morphology and excellent dart impact strength, while having excellent comonomer incorporation properties and a stable process during polyethylene production.

Disclosure of Invention

Technical problem

In the present invention, a composite supported metallocene catalyst is provided, which can be used to prepare a polyethylene copolymer having excellent mechanical properties due to excellent comonomer incorporation properties while maintaining high catalytic activity and stable process in ethylene polymerization.

In addition, a method for preparing a polyethylene copolymer using the composite supported metallocene catalyst is provided.

Technical scheme

In the present invention, there is provided a composite supported metallocene catalyst comprising at least one first metallocene compound selected from the group consisting of compounds represented by the following chemical formula 1; at least one second metallocene compound selected from compounds represented by the following chemical formula 2; and a support supporting the first and second metallocene compounds:

[ chemical formula 1]

(Cp¹R^a)_n(Cp²R^b)M¹Q¹ _3-n

In the chemical formula 1, the first and second,

M¹is a group 4 transition metal;

Cp¹and Cp²Are the same or different from each other, and are each independently any one selected from the group consisting of cyclopentadienyl, indenyl, 4,5,6, 7-tetrahydro-1-indenyl and fluorenyl, each of which has no substituent or is substituted with C_1-20A hydrocarbyl group;

R^aand R^bAre identical or different from each other and are each independently hydrogen, C_1-20Alkyl radical, C_1-20Alkoxy radical, C_2-20Alkoxyalkyl group, C_6-20Aryl radical, C_6-20Aryloxy radical, C_2-20Alkenyl radical, C_7-40Alkylaryl group, C_7-40Arylalkyl radical, C₈-₄₀Arylalkenyl or C_2-10Alkynyl with the proviso that R^aAnd R^bIs not hydrogen;

Q¹each independently of the other being halogen, C_1-20Alkyl radical, C_2-20Alkenyl radical, C_7-40Alkylaryl group, C_7-40Arylalkyl radical, C_6-20Aryl, substituted or unsubstituted C_1-20Alkylene (alkylene), substituted or unsubstituted amino, C_2-20Alkoxyalkyl group, C_2-20Alkyl alkoxy or C_7-40An arylalkoxy group; and is

n is 1 or 0;

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

M²is a group 4 transition metal;

a is carbon (C), silicon (Si) or germanium (Ge);

X¹and X²Are identical or different from each other and are each independently halogen or C_1-20An alkyl group;

L¹and L²Are identical to or different from each other and are each independently C_1-20An alkylene group;

D¹and D²Is oxygen;

R¹and R²Are identical to or different from each other and are each independently C_1-20Alkyl radical, C_2-20Alkenyl radical, C_6-20Aryl radical, C₇-₄₀Alkylaryl or C_7-40An arylalkyl group;

R³and R⁴Are identical to or different from each other and are each independently C_1-20An alkyl group.

In the present invention, there is also provided a method for preparing a polyethylene copolymer, which comprises the step of copolymerizing ethylene and an α -olefin in the presence of the above-mentioned composite supported metallocene catalyst.

In the present invention, there is also provided a polyethylene copolymer obtained by the above method.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

The singular forms also are intended to include the plural forms as well, unless the context clearly indicates otherwise.

In the present invention, the terms "comprises", "comprising" or "having" indicate the presence of stated features, integers, steps, components or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

The terms "about" or "substantially" as used throughout this specification are intended to have meanings close to the numerical values or ranges specified with an allowable error, and are intended to prevent any unreasonable third party from illegally or unfairly using the exact or absolute numerical values disclosed for the understanding of the present invention.

Unless otherwise indicated herein, "copolymerization" refers to block, random, graft, or alternating copolymerization, and "copolymer" refers to a block, random, graft, or alternating copolymer.

Also, as used herein, when it is stated that a layer or an element is formed "on" another layer or element, the layer or element may be directly formed on the other layer or element, or the other layer or element may be additionally formed between the layers, on the object or on the substrate.

Since the present invention is susceptible to various modifications and forms, specific embodiments thereof are shown by way of example and will herein be described in detail. However, it is not intended to limit the invention to the particular forms disclosed, and it should be understood that the invention includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

Hereinafter, the present invention will be described in detail.

According to an embodiment of the present invention, there is provided a composite supported metallocene catalyst comprising at least one first metallocene compound selected from the group consisting of compounds represented by the following chemical formula 1; at least one second metallocene compound selected from compounds represented by the following chemical formula 2; and a support supporting the first and second metallocene compounds:

[ chemical formula 1]

(Cp¹R^a)_n(Cp²R^b)M¹Q¹ _3-n

In the chemical formula 1, the first and second,

M¹is a group 4 transition metal;

Q¹each independently of the other being halogen, C_1-20Alkyl radical, C_2-20Alkenyl radical, C_7-40Alkylaryl group, C_7-40Arylalkyl radical, C_6-20Aryl, substituted or unsubstituted C_1-20Alkylene, substituted or unsubstituted amino, C_2-20Alkoxyalkyl group, C_2-20Alkyl alkoxy or C_7-40An arylalkoxy group; and is

n is 1 or 0;

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

M²is a group 4 transition metal;

a is carbon (C), silicon (Si) or germanium (Ge);

D¹and D²Is oxygen;

Unless otherwise indicated herein, the following terms may be defined as follows.

The hydrocarbon group is a monovalent functional group in the form of hydrogen removed from a hydrocarbon, and may include alkyl, alkenyl, alkynyl, aryl, aralkyl, aralkenyl, aralkynyl, alkylaryl, alkenylaryl, alkynylaryl, and the like. C_1-30The hydrocarbon group may be C_1-20Or C_1-10A hydrocarbyl group. For example, the hydrocarbyl group may be a linear, branched or cyclic alkyl group. More specifically, C_1-30The hydrocarbon group may be a linear, branched or cyclic alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, n-hexyl, n-heptyl, and cyclohexyl; or an aryl group such as phenyl, biphenyl, naphthyl, anthryl, phenanthryl or fluorenyl. Further, it may be an alkylaryl group such as methylphenyl, ethylphenyl, methylbiphenyl, and methylnaphthyl group, or an arylalkyl group such as phenylmethyl, phenylethyl, biphenylmethyl, and naphthylmethyl group. It may also be alkenyl, such as allyl, vinyl, propenyl, butenyl and pentenyl.

Hydrocarbyloxy (hydrocarbyloxy group) is a functional group formed by bonding a hydrocarbyl group and an oxygen group. Specifically, C_1-30The hydrocarbyloxy group may be C_1-20Or C_1-10A hydrocarbyloxy group. For example, the hydrocarbyloxy group may be a linear, branched or cyclic alkoxy group. More specifically, C_1-30The hydrocarbyloxy group may be a straight, branched or cyclic alkoxy group such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, tert-butoxy, n-pentoxy, n-hexoxy, n-heptoxy and cyclohexyloxy; or aryloxy groups such as phenoxy and naphthoxy.

Hydrocarbyloxy hydrocarbyl (hydrocarbyloxy hydrocarbyl group) is a functional group in which at least one hydrogen of a hydrocarbyl group is substituted with at least one hydrocarbyloxy group. Specifically, C_2-30The hydrocarbyloxy hydrocarbyl group may be C_2-20Or C_2-15A hydrocarbyloxy hydrocarbyl group. For example, the hydrocarbyloxy hydrocarbon group may be a linear, branched or cyclic hydrocarbyloxy hydrocarbon group. More specifically, C_2-30The hydrocarbyloxy hydrocarbyl group may be an alkoxyalkyl group, such as methoxymethyl, methoxyethyl, ethoxymethyl, isopropylOxymethyl, isopropoxyethyl, isopropoxyhexyl, tert-butoxymethyl, tert-butoxyethyl and tert-butoxyhexyl; or aryloxyalkyl, such as phenoxyhexyl.

The hydrocarbyl (oxy) silyl group being-SiH₃And 1 to 3 hydrogens of the functional group substituted with 1 to 3 hydrocarbon or hydrocarbonoxy groups. Specifically, C_1-30The hydrocarbyl (oxy) silyl group may be C_1-20、C_1-15、C_1-10Or C_1-5Hydrocarbyl (oxy) silyl groups. More specifically, C_1-30The hydrocarbyl (oxy) silyl group may be an alkylsilyl group such as methylsilyl, dimethylsilyl, trimethylsilyl, dimethylethylsilyl, diethylmethylsilyl or dimethylpropylsilyl; alkoxysilyl groups such as methoxysilyl, dimethoxysilyl, trimethoxysilyl or dimethoxyethoxysilyl; or an alkoxyalkyl silyl group such as a methoxydimethylsilyl group, a diethoxymethylsilyl group or a dimethoxypropylsilyl group.

C_1-20A silylhydrocarbyl group is a functional group in which at least one hydrogen of the hydrocarbyl group is replaced by a silyl group. The silyl group may be-SiH₃Or a hydrocarbyl (oxy) silyl group. Specifically, C_1-20The silylhydrocarbyl group may be C_1-15Or C_1-10A silyl hydrocarbyl group. More specifically, C_1-20The silylhydrocarbyl group may be a silylalkyl group, e.g. -CH₂-SiH₃(ii) a Alkylsilylalkyl groups such as methylsilylmethyl, methylsilylethyl, dimethylsilylmethyl, trimethylsilylmethyl, dimethylethylsilylmethyl, diethylmethylsilylmethyl or dimethylpropylsilylmethyl; or an alkoxysilylalkyl group, such as dimethylethoxysilylpropyl.

Halogen may be fluorine (F), chlorine (Cl), bromine (Br) or iodine (I).

C_1-20The alkyl group may be a linear, branched or cyclic alkyl group. Specifically, C_1-20The alkyl group may be C_1-20Straight chain alkyl；C_1-15A linear alkyl group; c_1-5A linear alkyl group; c_3-20A branched or cyclic alkyl group; c_3-15A branched or cyclic alkyl group; or C_3-10A branched or cyclic alkyl group. More specifically, C_1-20The alkyl group may be, but is not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, pentyl, hexyl, heptyl, octyl, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, or the like.

C_2-20The alkenyl group may be a linear, branched or cyclic alkenyl group. Specifically, it may be allyl, vinyl, propenyl, butenyl, pentenyl, or the like, but is not limited thereto.

C_1-20The alkoxy group may be methoxy, ethoxy, isopropoxy, n-butoxy, tert-butoxy, pentyloxy, cyclohexyloxy, or the like, but is not limited thereto.

C_2-20The alkoxyalkyl group is a functional group in which at least one hydrogen of the above-mentioned alkyl group is substituted with an alkoxy group, and it may be an alkoxyalkyl group such as, but not limited to, methoxymethyl, methoxyethyl, ethoxymethyl, isopropoxymethyl, isopropoxyethyl, isopropoxypropyl, isopropoxyhexyl, tert-butoxymethyl, tert-butoxyethyl, tert-butoxypropyl, and tert-butoxyhexyl, and the like.

C_6-20The aryloxy group may be phenoxy, biphenyloxy, naphthyloxy, or the like, but is not limited thereto.

C_7-40The aryloxyalkyl group is a functional group in which at least one hydrogen of the above-mentioned alkyl group is substituted with an aryloxy group, and it may be an aryloxyalkyl group such as phenoxymethyl, phenoxyethyl, phenoxyhexyl, or the like, but is not limited thereto.

C_1-20Alkylsilyl or C_1-20The alkoxysilyl group being-SiH₃A functional group in which 1 to 3 hydrogens of (a) are substituted with 1 to 3 of the above alkyl or alkoxy groups, and which may be an alkylsilyl group such as methylsilyl, dimethylsilyl, trimethylsilyl, dimethylethylsilyl, diethylmethylsilyl or dimethylpropylsilyl; alkoxysilyl groupFor example methoxysilyl, dimethoxysilyl, trimethoxysilyl or dimethoxyethoxysilyl; or an alkoxyalkyl silyl group such as a methoxydimethylsilyl group, a diethoxymethylsilyl group or a dimethoxypropylsilyl group; and the like, but are not limited thereto.

C_1-20The silylalkyl group is a functional group in which at least one hydrogen of the above-mentioned alkyl group is substituted with a silyl group, and it may be-CH₂-SiH₃Methylsilylmethyl or dimethylethoxysilylpropyl, and the like, but are not limited thereto.

In addition, C_1-20The alkylene or alkylidene group (alkylene) is the same as the above-mentioned alkyl group except that it is a divalent substituent, and it may be methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, octylene, cyclopropyl, cyclobutyl, cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, or the like, but is not limited thereto.

C_6-20The aryl group may be a monocyclic, bicyclic or tricyclic aromatic hydrocarbon. E.g. C_6-20The aryl group may be phenyl, biphenyl, naphthyl, anthryl, phenanthryl, fluorenyl, or the like, but is not limited thereto.

C_7-20The alkylaryl group may refer to a substituent in which at least one hydrogen of the aromatic ring is substituted with the above alkyl group. E.g. C_7-20The alkylaryl group may be a methylphenyl group, an ethylphenyl group, a methylbiphenyl group, a methylnaphthyl group or the like, but is not limited thereto.

C_7-20Arylalkyl may refer to a substituent in which at least one hydrogen of the alkyl group is replaced with an aryl group as described above. E.g. C_7-20The arylalkyl group may be a phenylmethyl, phenylethyl, biphenylmethyl, naphthylmethyl, or the like, but is not limited thereto.

In addition, C_6-20The arylene group and the arylidene group (aryliden) are the same as the above-mentioned aryl group except that they are divalent substituents, and they may be phenylene, biphenylene, naphthylene, anthracenylene, phenanthrenylene, fluorenylene or the like, but are not limited thereto.

The group 4 transition metal may be titanium (Ti), zirconium (Ti)Zr), hafnium (Hf) or

(Rf), and may specifically be titanium (Ti), zirconium (Zr) or hafnium (Hf). More specifically, it may be zirconium (Zr) or hafnium (Hf), but the present invention is not limited thereto.

Further, the group 13 element may be boron (B), aluminum (Al), gallium (Ga), indium (In), or thallium (Tl), and specifically may be boron (B) or aluminum (Al), but the present invention is not limited thereto.

The above substituents may be optionally substituted with one or more substituents selected from the group consisting of: a hydroxyl group; halogen; alkyl or alkenyl, aryl, alkoxy; alkyl or alkenyl, aryl, alkoxy containing at least one heteroatom from group 14 to 16 heteroatoms; a silyl group; an alkylsilyl or alkoxysilyl group; phosphine group (phosphine group); phosphide group (phosphide group); a sulfonic acid group; and a sulfone group.

Meanwhile, the composite supported metallocene catalyst of the invention is prepared by the following processes: the first metallocene compound capable of enhancing low molecular weight copolymerization and the second metallocene compound capable of increasing high molecular weight characteristics during ethylene polymerization are compositely supported, thereby exhibiting excellent process stability and high activity for ethylene polymerization. In addition, it can be used to prepare polyethylene copolymers having excellent mechanical properties by improving copolymerization of ethylene (comonomer incorporation).

In particular, in the composite supported metallocene catalyst of the embodiment, the first metallocene compound represented by chemical formula 1 contributes to the production of a low molecular weight linear copolymer, and the second metallocene compound represented by chemical formula 2 contributes to the production of a high molecular weight linear copolymer. The composite supported metallocene catalyst can exhibit excellent supporting performance, catalytic activity and high comonomer incorporation amount by using the first metallocene compound having a low comonomer incorporation amount and the second metallocene compound having a high comonomer incorporation amount as a composite catalyst. In particular, when a low density polyethylene is produced in a slurry process in the presence of a composite supported metallocene catalyst, the stability in the process is improved, so that the fouling problems occurring in the prior art can be prevented. In addition, by using the composite supported metallocene catalyst, polyethylene having excellent physical properties, such as low density polyethylene, can be provided.

Specifically, the first metallocene compound is characterized by having a form in which cyclopentadienyl, indenyl or fluorenyl ligands are bridged with a group 4 transition metal, and these ligands are at least one of the substituents other than hydrogen in formula 1. For example, the cyclopentadienyl, indenyl or fluorenyl ligands may be unsubstituted or substituted by C_1-20Hydrocarbyl or C_1-12A hydrocarbyl group. In particular, the cyclopentadienyl, indenyl or fluorenyl ligands are substituted with at least one alkyl or alkenyl, alkoxyalkyl or arylalkyl group or the like. Then, by applying the cyclopentadienyl, indenyl or fluorenyl ligand having the above-mentioned specific structure, the catalytic activity and copolymerizability can be improved, the molecular structure of the resulting polymer can be improved, and the reactivity can be well controlled.

In chemical formula 1, M¹It may be zirconium (Zr) or hafnium (Hf), preferably zirconium (Zr).

And, in chemical formula 1, Cp¹And Cp²Each may be cyclopentadienyl, indenyl or fluorenyl. Preferably, Cp¹And Cp²At least one of which is cyclopentadienyl or indenyl. More preferably, Cp¹And Cp²May be cyclopentadienyl.

Cp¹And Cp²May be unsubstituted or substituted by at least one C_1-20A hydrocarbyl group. For example, Cp¹And Cp²May be substituted by C_1-10Hydrocarbyl radical, C_1-10Hydrocarbyloxy or C_1-10One or more hydrocarbyloxy hydrocarbyl groups. In particular Cp¹And Cp²May be substituted with one or more of methyl, ethyl, n-propyl, n-butyl, t-butyl, n-pentyl, n-hexyl, t-butoxyhexyl, butenyl, phenylpropyl, phenylhexyl or phenyl.

More specifically, in the first metallocene compound, Cp¹And Cp²May be the same as or different from each other. Preferably, Cp¹And Cp²May be identical to each other and include the same substituents to form a symmetrical structure.

In addition, R^aAnd R^bEach is hydrogen, C_1-6Straight or branched alkyl, C_2-6Alkynyl, C_1-6Alkoxy-substituted C_1-6Alkyl radical, C_6-12Aryl substituted C_1-6Alkyl or C_6-12Aryl with the proviso that R^aAnd R^bIs not hydrogen. In particular, R^aAnd R^bMay be the same or different from each other, e.g. R^aAnd R^bMay be identical to each other and may have a symmetrical structure in formula 1. For example, R^aAnd R^bEach may be hydrogen, methyl (Me), ethyl (Et), n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), tert-butyl (t-Bu), n-pentyl (n-Pt), n-hexyl (n-Hex), tert-butoxy (t-Bu-O) hexyl, butenyl, phenylpropyl, phenylhexyl or phenyl (Ph).

In chemical formula 1, each Q1 may be a halogen, such as chlorine.

In chemical formula 1, n is 1 or 0, preferably n is 1.

Meanwhile, the first metallocene compound may be represented by any one of the following chemical formulas 1-1 to 1-5.

[ chemical formula 1-1]

[ chemical formulas 1-2]

[ chemical formulas 1-3]

[ chemical formulas 1 to 4]

[ chemical formulas 1 to 5]

In chemical formulas 1-1 to 1-5,

M¹and Q¹As defined in chemical formula 1, as well,

r 'and R' are the same or different from each other and each independently represents hydrogen, C_1-20Alkyl radical, C_1-20Alkoxy radical, C_2-20Alkoxyalkyl group, C_6-20Aryl radical, C_6-20Aryloxy radical, C_2-20Alkenyl radical, C_7-40Alkylaryl group, C_7-40Arylalkyl radical, C_8-40Arylalkenyl or C_2-10Alkynyl, provided that at least one of R' and R "is not hydrogen;

m1 is each independently an integer from 1 to 8;

m2 is each independently an integer from 1 to 6.

More preferably, the first metallocene compound may be represented by chemical formula 1-1.

In the chemical formulas 1-1 to 1-5, R 'and R' are each hydrogen, C_1-6Straight or branched alkyl, C_2-6Alkynyl, C_1-6Alkoxy-substituted C_1-6Alkyl radical, C_6-12Aryl substituted C_1-6Alkyl, or C_6-12Aryl, provided that at least one of R 'and R' is not hydrogen. Preferably, at least one of R 'and R' is methyl (Me), ethyl (Et), n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), t-butyl (t-Bu), n-pentyl (n-Pt), n-hexyl (n-Hex), t-butoxy (t-Bu-O) hexyl, butenyl, phenylpropyl, phenylhexyl, or phenyl (Ph), and the remainder is hydrogen.

Further, in chemical formulas 1-1 to 1-5, m1 and m2 are each an integer of 1 to 4, preferably 1 or 2, respectively.

In addition, the first metallocene compound may be represented by one of the following structural formulae.

The first metallocene compound represented by the above structural formula can be synthesized by a known reaction, and a more detailed synthesis method can be understood with reference to examples.

Meanwhile, the composite supported metallocene catalyst of the present invention is characterized by comprising a second metallocene compound represented by chemical formula 2 and the first metallocene compound.

Specifically, the second metallocene compound is characterized by having a form in which two indenyl ligands are bonded to each other through a group 4 transition metal bridge and a carbon or silicon bridge, and the hydrogens at the 2-and 4-positions of the indenyl ligands are each substituted with a methyl group and an aryl group substituted with a hydrocarbyloxy hydrocarbon group, respectively. In particular, it is characterized in that the two indenyl ligands having such a specific substituent are contained in the same symmetrical structure with each other. Then, a bis-indenyl ligand having a specific structure and substituents is used, thereby improving the process stability by reducing the ratio of ethylene and comonomer in the reaction system with high copolymerizability, and copolymerizing (comonomer incorporation amount) due to high comonomer in the polymer region of the resulting polyethylene molecular weight distribution profile. Thus, a linear low density polyethylene product having excellent morphology and high impact strength can be produced.

In chemical formula 2, M²It may be zirconium (Zr) or hafnium (Hf), preferably zirconium (Zr).

And, in chemical formula 2, a may be silicon (Si).

In chemical formula 2, X¹And X²Each may be halogen, in particular chlorine.

Further, in chemical formula 2, L¹And L²May each be C_1-3Alkylene, and specifically may be methylene, ethylene or propylene.

In chemical formula 2, D¹And D²Is oxygen (O).

In chemical formula 2, R¹And R²Each may be C_1-6Straight or branched alkyl, or C_6-12And (4) an aryl group. For example, R¹And R²May be identical to each other and may each be methyl (Me), ethyl (Et), n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), tert-butyl (t-Bu) or phenyl (Ph).

Also, in chemical formula 2, R³And R⁴May each independently be straight or branched C_1-6An alkyl group. In particular, R³And R⁴May be identical to each other and may each be a straight chain C_1-6An alkyl group. For example, R³And R⁴Each may be methyl (Me), ethyl (Et), n-propyl (n-Pr), n-butyl (n-Bu), n-pentyl (n-Pt) or n-hexyl (n-Hex).

Meanwhile, the second metallocene compound may be represented by the following chemical formula 2-1.

[ chemical formula 2-1]

In chemical formula 2-1, M²、A、X¹、X²、R¹、R²、R³And R⁴The same as defined in chemical formula 2.

Specifically, the second metallocene compound may be represented by one of the following structural formulae.

The second metallocene compound represented by the above structural formula can be synthesized by a known reaction, and a more detailed synthesis method can be understood with reference to examples.

Meanwhile, in the method for preparing the metallocene compound, the composite supported catalyst or the catalyst composition of the present invention, the equivalent (eq) means a molar equivalent (eq/mol).

In particular, in the composite supported metallocene catalyst of the present invention, the first metallocene compound may be represented by any one of the following chemical formulas 1-1 to 1-5, and the second metallocene compound may be represented by the following chemical formula 2-1:

[ chemical formula 1-1]

[ chemical formulas 1-2]

[ chemical formulas 1-3]

[ chemical formulas 1 to 4]

[ chemical formulas 1 to 5]

In chemical formulas 1-1 to 1-5,

M¹and Q¹As defined in chemical formula 1, as well,

r 'and R' are the same or different from each other and each independently represents hydrogen, C_1-20Alkyl radical, C_1-20Alkoxy radical, C_2-20Alkoxyalkyl group, C_6-20Aryl radical, C_6-20Aryloxy radical, C_2-20Alkenyl radical, C_7-40Alkylaryl group, C_7-40Arylalkyl radical, C_8-40Arylalkenyl or C_2-10Alkynyl, provided that at least one of R 'and R' isIs not hydrogen;

m1 is each independently an integer from 1 to 8;

m2 is each independently an integer from 1 to 6,

[ chemical formula 2-1]

In addition, the composite supported metallocene catalyst of the present invention may have a specific structure and substituents. Specifically, in chemical formulas 1-1 to 1-5, M¹Is Zr; q¹All are Cl; and at least one of R 'and R' is methyl (Me), ethyl (Et), n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), t-butyl (t-Bu), n-pentyl (n-Pt), n-hexyl (n-Hex), t-butoxy (t-Bu-O) hexyl, butenyl, phenylpropyl, phenylhexyl, or phenyl (Ph), and the remainder of R 'and R' is hydrogen. Also, in chemical formula 2-1, M²Is Zr; x¹And X²Is Cl; r¹And R²Identical to each other and selected from methyl (Me), ethyl (Et), n-propyl (n-Pr), isopropyl (i-Pr), n-butyl (n-Bu), tert-butyl (t-Bu) or phenyl (Ph); r³And R⁴Identical to each other and chosen from methyl (Me), ethyl (Et), n-propyl (n-Pr), n-butyl (n-Bu), n-pentyl (n-Pt) or n-hexyl (n-Hex).

In the present invention, the first metallocene compound and the second metallocene compound may be meso-isomer, racemic-isomer or a mixture thereof.

In the present invention, "racemic form", "racemate" or "racemic isomer" means that the same substituents on both cyclopentadienyl moieties are represented relative to the group consisting of M contained in chemical formula 1 or 2¹Or M²The plane of the represented transition metal (e.g., zirconium (Zr) or hafnium (Hf)) and the center of the cyclopentadienyl moiety are located on opposite sides.

In addition, "meso form" or "meso isomer" refers to a stereoisomer of the above racemic isomer, wherein the same substituent on both cyclopentadienyl moieties is represented by the formula M contained in chemical formula 1 or 2¹Or M²The planes of the represented transition metals (e.g., zirconium (Zr) or hafnium (Hf)) and the center of the cyclopentadienyl moiety are located on the same side.

Meanwhile, in the composite supported metallocene catalyst of the present invention, the first metallocene compound and the second metallocene compound may be supported at a molar ratio of about 0.3:1 to about 4: 1. When the first and second metallocene compounds are contained in the above molar ratio, excellent supporting properties, catalytic activity and high comonomer incorporation amount can be exhibited. In particular, when a low density polyethylene is produced in a slurry process in the presence of a composite supported metallocene catalyst, the stability in the process is improved, so that the fouling problems occurring in the prior art can be prevented. For example, when the loading ratio of the first metallocene compound and the second metallocene compound exceeds about 4:1, only the first metallocene compound plays a dominant role and the copolymerizability is reduced, and thus it may be difficult to produce low density polyethylene. In addition, when the loading ratio is less than about 0.3:1, only the second metallocene compound plays a dominant role, and it may be difficult to obtain the resulting polymer of a desired molecular structure.

Specifically, the composite supported metallocene catalyst in which the first metallocene compound and the second metallocene compound are supported at a molar ratio of about 0.5:1 to about 4:1, or about 1:1 to about 2:1 exhibits high activity and high comonomer incorporation amount in ethylene polymerization, and is preferably used for preparing polyethylene having excellent mechanical properties.

That is, the composite supported metallocene catalyst of the present invention in which the first metallocene compound and the second metallocene compound are supported at the above molar ratio can further improve the physical properties of polyethylene and films thereof due to the interaction between two or more catalysts.

In the composite supported metallocene catalyst of the present invention, a support having a hydroxyl group on the surface thereof may be used as a support for supporting the first metallocene compound and the second metallocene compound. Preferably, a carrier containing highly reactive hydroxyl and siloxane groups, which has been dried to remove moisture on the surface, may be used.

For example, the carrier may be at least one selected from the group consisting of silica dried at high temperature, silica-alumina or silica-magnesia, and generally contains oxides, carbonates, sulfates and nitrates, such as Na₂O、K₂CO₃、BaSO₄And Mg (NO)₃)₂And the like.

The drying temperature of the support may preferably be about 200 to 800 deg.c, more preferably about 300 to 600 deg.c, most preferably about 300 to 400 deg.c. When the drying temperature of the support is less than 200 ℃, surface moisture may react with a cocatalyst described later due to excessive moisture. When it is more than 800 deg.c, pores on the surface of the support may be combined, reducing the surface area, and the surface may lose a large amount of hydroxyl groups while leaving only siloxane groups, thereby reducing the reaction sites with the cocatalyst, which is not preferable.

The amount of hydroxyl groups on the surface of the support may preferably be about 0.1 to 10mmol/g, more preferably about 0.5 to 5 mmol/g. The amount of hydroxyl groups on the surface of the support can be controlled by the preparation method and conditions of the support or drying conditions (e.g., temperature, time, vacuum or spray drying, etc.).

When the amount of the hydroxyl group is less than about 0.1mmol/g, the reaction site with the cocatalyst may be rare, and when it is more than about 10mmol/g, it may be caused by moisture in addition to the hydroxyl group on the surface of the support particle, which is not preferable.

For example, the total amount of the first and second metallocene compounds supported on the support (e.g., silica), i.e., the supported amount of the metallocene compound, may be 0.01mmol/g to 1mmol/g based on 1g of the support. That is, in view of the effect of the metallocene compound on the catalyst, it is preferable to control the amount to be within the above range.

Meanwhile, the composite supported metallocene catalyst may be a catalyst in which at least one first metallocene compound and at least one second metallocene compound are supported together with a cocatalyst compound on a carrier. The cocatalyst may be any cocatalyst used for olefin polymerization in the presence of a general metallocene catalyst. This co-catalyst causes a bond to be formed between the hydroxyl group in the support and the group 13 transition metal. In addition, since the cocatalyst is present only on the surface of the support, it can contribute to achieving the inherent characteristics of the specific composite catalyst composition of the present invention without fouling phenomena of polymer particles agglomerating to the reactor walls or each other.

In addition, the composite supported metallocene catalyst of the present invention may further comprise at least one cocatalyst selected from the group consisting of compounds represented by the following chemical formulas 3 to 5.

[ chemical formula 3]

-[Al(R³¹)-O]_c-

In the chemical formula 3, the first and second,

R³¹each independently is halogen, C_1-20Alkyl or C_1-20A halogenated alkyl group, and

c is an integer of 2 or more;

[ chemical formula 4]

D(R⁴¹)₃

In the chemical formula 4, the first and second organic solvents,

d is aluminum or boron, and

R⁴¹each independently of the others is hydrogen, halogen, C_1-20Hydrocarbyl or halogen-substituted C_1-20A hydrocarbon group,

[ chemical formula 5]

[L-H]⁺[Q(E)₄]^-Or [ L]⁺[Q(E)₄]^-

In the chemical formula 5, the first and second organic solvents,

l is a neutral or cationic lewis base;

[L-H]⁺is a Bronsted acid and is a Bronsted acid,

q is B³⁺Or Al³⁺And is and

e is each independently C_6-40Aryl or C_1-20Alkyl radical, provided that C is_6-40Aryl or C_1-20The alkyl group may be unsubstituted or substituted by a substituent selected from the group consisting of halogenElement, C_1-20Alkyl radical, C_1-20Alkoxy or C_6-40At least one substituent of the group consisting of aryloxy.

The compound represented by chemical formula 3 may be alkylaluminoxane such as Modified Methylaluminoxane (MMAO), Methylaluminoxane (MAO), ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc.

The metal alkyl compound represented by chemical formula 4 may be trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, dimethylasobutylaluminum, dimethylethylaluminum, diethylaluminum chloride, triisopropylaluminum, tri-sec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylaluminum methoxide (dimethylaluminum methoxide), dimethylaluminum ethoxide (dimethylaluminum ethoxide), trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, or the like.

The compound represented by chemical formula 5 may be triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra (p-tolyl) boron, tripropylammonium tetra (p-tolyl) boron, triethylammonium tetra (o, p-dimethylphenyl) boron, trimethylammonium tetra (o, p-dimethylphenyl) boron, tributylammonium tetra (p-trifluoromethylphenyl) boron, trimethylammonium tetra (p-trifluoromethylphenyl) boron, tributylammonium tetrapentafluorophenylboron, N-dimethylanilinium tetraphenylboron, N-diethylanilinium tetraphenylboron, N-diethylanilinium tetrapentafluorophenylboron, triphenylphosphonium tetraphenylboron, trimethylphosphonium tetraphenylboron, triethylammonium tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, Tripropylammonium tetraphenylaluminum, trimethylammonium tetrakis (p-tolyl) aluminum, tripropylammonium tetrakis (p-tolyl) aluminum, triethylammonium tetrakis (o, p-dimethylphenyl) aluminum, tributylammonium tetrakis (p-trifluoromethylphenyl) aluminum, trimethylammonium tetrakis (p-trifluoromethylphenyl) aluminum, tributylammonium tetrapentafluorophenylaluminum, N-dimethylanilinium tetraphenylaluminum, N-diethylanilinium tetrapentafluorophenylaluminum, diethylammonium tetrapentafluorophenylaluminum, triphenylphosphonium tetraphenylaluminum, trimethylphosphonium tetraphenylaluminum, triphenylcarbonium tetraphenylboron, triphenylcarbonium tetraphenylaluminum, triphenylcarbonium tetrakis (p-trifluoromethylphenyl) boron or triphenylcarbonium tetrapentafluorophenylboron, and the like.

In addition, the composite supported metallocene catalyst may comprise the cocatalyst and the first metallocene compound in a molar ratio of about 1:1 to about 1:10000, preferably about 1:1 to about 1:1000, more preferably about 1:10 to about 1: 100.

In addition, the composite supported metallocene catalyst may comprise the cocatalyst and the second metallocene compound in a molar ratio of about 1:1 to about 1:10000, preferably about 1:1 to about 1:1000, more preferably about 1:10 to about 1: 100.

At this time, if the molar ratio is less than about 1, the metal content of the cocatalyst is too small, and thus the catalytically active species are not well formed, resulting in low activity. If the molar ratio exceeds about 10000, the metal of the cocatalyst acts as a catalyst poison.

The supported amount of the cocatalyst may be about 5mmol to about 20mmol based on 1g of the support.

Meanwhile, the composite supported metallocene catalyst may be prepared by a method comprising the steps of: supporting a cocatalyst on a support; supporting a first metallocene compound on a cocatalyst-supporting support; and supporting a second metallocene compound on a support supporting a cocatalyst and the first metallocene compound.

Alternatively, the composite supported metallocene catalyst may be prepared by a method comprising the steps of: supporting a cocatalyst on a support; supporting a second metallocene compound on a cocatalyst-supporting support; and supporting the first metallocene compound on a support supporting a cocatalyst and a second metallocene compound.

Alternatively, the composite supported metallocene catalyst may be prepared by a method comprising the steps of: supporting a first metallocene compound on a support; supporting a cocatalyst on a support on which a first metallocene compound is supported; and supporting a second metallocene compound on a support supporting a cocatalyst and the first metallocene compound.

In the above method, the loading conditions are not particularly limited, and the loading step may be performed within a range well known to those skilled in the art. For example, the supporting step may be suitably performed at high and low temperatures. For example, the loading temperature may be in the range of about-30 ℃ to about 150 ℃, preferably in the range of about 50 ℃ to about 98 ℃, or about 55 ℃ to about 95 ℃. The supporting time may be appropriately controlled according to the amount of the first metallocene compound to be supported. The supported catalyst after the reaction may be used without further treatment after removing the reaction solvent by filtration or distillation under reduced pressure, or may be subjected to Soxhlet filtration using an aromatic hydrocarbon (e.g., toluene) as necessary.

The preparation of the supported catalyst can be carried out with or without a solvent. When a solvent is used, an aliphatic hydrocarbon solvent (e.g., hexane or pentane), an aromatic hydrocarbon solvent (e.g., toluene or benzene), a chlorinated hydrocarbon solvent (e.g., dichloromethane), an ether solvent (e.g., diethyl ether or Tetrahydrofuran (THF)), and a common organic solvent (e.g., acetone or ethyl acetate) may be included. Preferably, hexane, heptane, toluene or dichloromethane is used.

Also, provided is a method for preparing a polyethylene copolymer, comprising the step of copolymerizing ethylene with an α -olefin in the presence of the above-mentioned composite supported metallocene catalyst.

The composite supported metallocene catalyst can show excellent supporting performance, catalytic activity and high comonomer incorporation amount. Therefore, even when a low density polyethylene is produced in a slurry process in the presence of the hybrid supported metallocene catalyst, the conventional problems of low productivity and fouling can be prevented and the process stability can be improved.

The process for the preparation of the polyethylene copolymer can be carried out by slurry polymerization using ethylene and α -olefin as raw materials in the presence of the above-mentioned composite supported metallocene catalyst using conventional equipment and contact techniques.

The preparation method of the polyethylene copolymer may be performed by copolymerizing ethylene and α -olefin using a continuous slurry polymerization reactor or a loop slurry reactor, etc., but is not limited thereto.

Specifically, the copolymerization reaction may be performed by reacting the α -olefin in an amount of about 0.45 mol or less or about 0.1 to about 0.45 mol based on 1mol of ethylene. More specifically, the α -olefin is about 0.4 moles or less, or about 0.38 moles or less, or about 0.35 moles or less, or about 0.31 moles or less, and about 0.15 moles or more, or about 0.2 moles or more, or about 0.25 moles or more, or about 0.28 moles or more, based on 1 mole of ethylene.

In the production process of the polyethylene copolymer of the present invention, it is not necessary to increase the comonomer content to lower the product density, and therefore the process can be stabilized and high dart drop impact strength of the product can be obtained.

In addition, the α -olefin may be at least one selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, and mixtures thereof. Preferably, the alpha-olefin may be 1-hexene.

Specifically, in the production of the polyethylene copolymer, for example, 1-hexene may be used as the α -olefin. Thus, in slurry polymerization, a low density polyethylene copolymer can be prepared by polymerizing ethylene and 1-hexene.

In addition, the polymerization can be carried out at a temperature of from about 25 ℃ to about 500 ℃, from about 25 ℃ to about 300 ℃, from about 30 ℃ to about 200 ℃, from about 50 ℃ to about 150 ℃, or from about 60 ℃ to about 120 ℃. Additionally, the polymerization may be conducted at a pressure of from about 1 bar to about 100 bar, or from about 5 bar to about 90 bar, or from about 10 bar to about 80 bar, or from about 15 bar to about 70 bar, or from about 20 bar to about 60 bar.

In addition, the supported metallocene catalyst may be dissolved or diluted in C_5-12Aliphatic hydrocarbon solvents (e.g., pentane, hexane, heptane, nonane, decane) and isomers thereof, aromatic hydrocarbon solvents (e.g., toluene and benzene), or hydrocarbon solvents substituted with chlorine (e.g., dichloromethane and chlorobenzene), and injected. The solvent used herein is preferably used after removing a small amount of water or air serving as a catalyst poison by treatment with a small amount of aluminum alkyl. A cocatalyst may be further used.

For example, the polymerization reaction can be conducted in the presence of hydrogen in an amount of about 800ppm or less, or about 0 to about 800ppm, or about 300ppm or less, or about 10ppm to about 300ppm, or about 100ppm or less, or about 15ppm to about 100ppm based on the ethylene content.

In such an ethylene polymerization process, the transition metal compound of the present invention can exhibit high catalytic activity. For example, the catalyst activity during ethylene polymerization is about 4.8kg PE/g cat hr or more, or about 4.8kg PE/g cat hr to about 50kg PE/g cat hr or more, specifically about 5.0kg PE/g cat hr or more, or about 5.0kg PE/g cat hr to about 40kg PE/g cat hr, or more specifically about 5.1kg PE/g cat hr or more, or about 5.1kg PE/g cat hr to about 35kg PE/g cat hr. Here, the catalyst activity is calculated as the ratio of the weight of the produced polyethylene (kg PE) to the weight of the supported catalyst used (g) on the unit time (h) basis.

As described above, the polyethylene copolymer of the present invention can be prepared by copolymerizing ethylene and α -olefin using the above-described supported metallocene catalyst.

Here, the polyethylene to be prepared may be an ethylene-1-hexene copolymer.

According to another embodiment of the present invention, there is provided a polyethylene copolymer obtained by the above method.

The preparation method of the polyethylene copolymer can provide the polyethylene copolymer having excellent mechanical properties by performing slurry polymerization in the presence of the above-mentioned composite supported metallocene catalyst.

Meanwhile, Linear Low Density Polyethylene (LLDPE) is produced by copolymerizing ethylene and α -olefin using a polymerization catalyst at low pressure. Linear low density polyethylene is a resin with a narrow molecular weight distribution and short chain branches of a predetermined length. In particular, a linear low density polyethylene film has high breaking strength and elongation and characteristics of general polyethylene, and has excellent tear strength and dart impact strength. Therefore, linear low density polyethylene films are increasingly used for stretched films and overlapped films, etc. to which conventional low density polyethylene or high density polyethylene is difficult to apply.

Further, it is generally known that as the density decreases, the transparency and dart impact strength of conventional linear low density polyethylene increase. However, when a large amount of comonomer is used to produce low density polyethylene, the occurrence of fouling in the slurry polymerization process increases, and in manufacturing a film comprising the same, the amount of antiblocking agent must be increased due to stickiness. In addition, there is a problem that the process is unstable during the production process or the morphological characteristics of the produced polyethylene are deteriorated, thereby decreasing the bulk density.

In the present invention, the above-described composite supported metallocene catalyst can provide a high dart drop impact strength of a polyethylene copolymer and a film using the same having excellent mechanical properties while preventing problems associated with productivity reduction and fouling, which typically occur when a low density polyethylene copolymer is prepared by slurry polymerization.

Thus, the polyethylene copolymer may have a density of about 0.930g/cm according to American Society for Testing and Materials (ASTM) ASTM D792³The following low density polyethylene. Specifically, the density is about 0.910g/cm³Above, or about 0.911g/cm³Above, or about 0.912g/cm³Above, or about 0.913g/cm³Above, or about 0.915g/cm³Above, and about 0.925g/cm³About 0.923g/cm³Less than, or about 0.920g/cm³Less than, or about 0.918g/cm³Less than, or about 0.917g/cm³Less than, or about 0.9168g/cm³The following. The density of the polyethylene copolymer should satisfy the above range in terms of ensuring excellent transparency and high impact strength during film processing.

Melt Index (MI) of polyethylene copolymer measured according to American society for testing and materials Standard ASTM D1238_2.16190 ℃, measured under a 2.16kg load) is from about 0.5g/10min to about 2.0g/10 min. Specifically, Melt Index (MI)_2.16190 ℃, measured under a 2.16kg load) is about 0.7g/10min or more, about 0.8g/10min or more, about 0.9g/10min or more, or about 0.98g/10min or more, and about 1.8g/10min or less, or about 1.5g/10min or less.

Further, the Bulk Density (BD) of the polyethylene copolymer, as measured according to ASTM D1895, the American society for materials and testing, may be about 0.2g/mL or greater, or about 0.2g/mL to about 0.7 g/mL. Specifically, the bulk density is about 0.25g/mL or more, or about 0.3g/mL or more, or about 0.35g/mL or more, or about 0.4g/mL or more, or about 0.41g/mL or more, and about 0.6g/mL or less, or about 0.5g/mL or less, or about 0.48g/mL or less, or about 0.47g/mL or less, or about 0.46g/mL or less, or about 0.45g/mL or less. The bulk density should satisfy the above range in terms of ensuring excellent morphology of the polyethylene copolymer.

In particular, a polyethylene copolymer film prepared using a film applicator (BUR 2.3, film thickness 48 μm to 52 μm, e.g., film thickness 50 μm) of a polyethylene copolymer as measured according to American society for materials and testing Standard ASTM D1709 may have a dart drop impact strength of 1200g or more, or about 1200g to about 3500 g. Specifically, the dart drop impact strength can be about 1350g or greater, or about 1500g or greater, or about 1550g or greater, or about 1600g or greater, or about 1650g or greater, or about 1700g or greater. The upper limit is not particularly limited as the dart impact strength value is higher, and therefore, the upper limit is not particularly limited, but is about 3200g or less, or about 3000g or less, or about 2800g or less, or about 2500g or less, or about 2200g or less, or about 2000g or less. The dart impact strength of the polyethylene copolymer should satisfy the above range in terms of ensuring high mechanical properties and excellent processability in forming a film (e.g., blown film).

Further, a polyethylene copolymer film (BUR 2.3, film thickness of 48 μm to 52 μm, for example, film thickness of 50 μm) of the polyethylene copolymer prepared using a film coater, measured in accordance with International organization for standardization ISO 13468, has a haze of 12% or less. Specifically, the haze may be about 11% or less, or about 10% or less, or about 9% or less. The lower the haze value, the better, and therefore the lower limit is not particularly limited, but may be, for example, about 4% or more, or about 5% or more, or about 6% or more.

Meanwhile, the polyethylene copolymer may have a molecular weight distribution (Mw/Mn) of about 2.0 to about 6.0, or about 2.0 to about 5.0, or about 2.0 to about 4.0.

For example, the molecular weight distribution (Mw/Mn) can be calculated by the following procedure: the weight average molecular weight (Mw) and the number average molecular weight (Mn) were measured using gel permeation chromatography (GPC, manufactured by Water), and then the weight average molecular weight (Mw) was divided by the number average molecular weight (Mn).

Specifically, the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the polyethylene copolymer can be measured in terms of polystyrene standards by Gel Permeation Chromatography (GPC). For example, PL-GPC220 manufactured by Waters can be used as a Gel Permeation Chromatography (GPC) instrument, and Polymer Laboratories PLgel MIX-B300 mm long column can be used. The evaluation temperature may be 160 ℃ and 1,2, 4-trichlorobenzene may be used as a solvent at a flow rate of 1 mL/min. Each polyethylene sample can be pretreated by dissolving in 1,2, 4-trichlorobenzene containing 0.0125% BHT at 160 ℃ for 10 hours using a GPC analyzer (PL-GP220), and a sample having a concentration of 10mg/10mL can be supplied in an amount of 200. mu.L. Mw and Mn can be obtained using calibration curves formed using polystyrene standards. 9 polystyrene standards can be used, with a weight average molecular weight of 2000g/mol, 10000g/mol, 30000g/mol, 70000g/mol, 200000g/mol, 700000g/mol, 2000000g/mol, 4000000g/mol, and 10000000 g/mol.

The weight average molecular weight of the polyethylene copolymer may be from about 50000g/mol to about 200000 g/mol. Specifically, the weight average molecular weight of the polyethylene copolymer may be about 60000g/mol or more, or about 65000g/mol or more, or about 70000g/mol or more, and about 190000g/mol or less, or about 180000g/mol or less, or about 150000g/mol or less.

Thus, the polyethylene copolymers of the present invention can be used in a variety of applications where such physical properties are desired. In particular, it is useful in agricultural/industrial and packaging applications where high dart impact resistance is required. It can also be used for shrink films where conventional low density polyethylene or high density polyethylene is difficult to apply.

Advantageous effects

The composite supported metallocene catalyst of the present invention exhibits excellent process stability and high activity for ethylene polymerization, and can prepare a polyethylene copolymer having excellent mechanical properties by increasing the comonomer incorporation amount during ethylene polymerization.

Detailed Description

Hereinafter, the action and effect of the present invention will be described in more detail by specific examples. However, these examples are for illustrative purposes only, and the present invention is not intended to be limited to these examples.

[ examples ]

< preparation of first metallocene Compound >

Synthesis example 1

N-butyl chloride was reacted with cyclopentadienyl sodium (NaCp) to obtain n-butylcyclopentadiene (n-BuCp). Thereafter, n-BuCp was dissolved in Tetrahydrofuran (THF) at-78 deg.C, n-butyllithium (n-BuLi, 2.5M in hexane) was slowly added thereto, and then the temperature was raised to room temperature, followed by carrying out the reaction for 8 hours. The prepared lithium salt solution was cooled to-78 ℃ and slowly added to ZrCl at this temperature₄(THF)₂(1.70g,4.50mmol) in THF (30 mL). Then, the reaction mixture was allowed to warm to room temperature, followed by reaction for 6 hours. Thereafter, all volatile substances of the reaction mixture were removed by vacuum drying, and a hexane solvent was added to the obtained oily liquid substance, followed by filtration to obtain a solution containing the reaction product. After drying the filtered solution under vacuum, hexane was added to initiate precipitation at low temperature (-20 ℃). The obtained precipitate was filtered at low temperature to obtain [ (CH) as a white solid₃)(CH₂)₃-C₅H₄]₂ZrCl₂(yield 50%).

Synthesis example 2

tert-butyl-O- (CH)₂)₆-Cl is prepared by a method described in the literature (Tetrahedron Lett.2951,1988) using 6-chlorohexanol and reacting it with sodium cyclopentadienyl (NaCp) to obtain tert-butyl-O- (CH-O-H-C-H-O-H-C-H-C-H-S-C-L-C-H-L-C-H-L-C-L-S₂)₆-C₅H₅(yield 60%, b.p.80 ℃/0.1 mmHg).

Furthermore, tert-butyl-O- (CH) is reacted at-78 deg.C₂)₆-C₅H₅Dissolved in Tetrahydrofuran (THF), n-butyllithium (n-BuLi, 2.5M in hexane) was slowly added thereto, and then the temperature was raised to room temperature, followed by carrying out a reaction for 8 hours. The prepared lithium salt solution was cooled to-78 ℃ and slowly added to ZrCl at this temperature₄(THF)₂(1.70g,4.50mmol) in THF (30 mL). Then, the reaction mixture was allowed to warm to room temperature, followed by reaction for 6 hours. Thereafter, all volatile substances of the reaction mixture were removed by vacuum drying, and a hexane solvent was added to the obtained oily liquid substance, followed by filtration to obtain a solution containing the reaction product. After vacuum drying of the filtered solution, hexane was added to induce precipitation at low temperature (-20 ℃). The obtained precipitate was filtered at low temperature to obtain [ tert-butyl-O- (CH) as a white solid₂)₆-C₅H₄]₂ZrCl₂](yield 92%).

¹H-NMR(300MHz,CDCl₃,ppm):δ6.28(t,J＝2.6Hz,2H),6.19(t,J＝2.6Hz,2H),3.31(t,6.6Hz,2H),2.62(t,J＝8Hz),1.7–1.3(m,8H),1.17(s,9H)。

¹³C-NMR(300MHz,CDCl₃,ppm):δ135.09,116.66,112.28,72.42,61.52,30.66,30.31,30.14,29.18,27.58,26.00。

Comparative Synthesis example 1

Synthesis of (6-t-butoxyhexyl) (fluorenyl) methylsilane

Reacting the compound tert-butyl-O- (CH)₂)₆Cl and Mg (0) in diethyl ether (Et)₂O) to obtain 0.14mol of Grignard reagent tBu-O- (CH)₂)₆MgCl solution. At-100 deg.C, adding methyl trichlorosilane (MeSiCl)₃) Compound (24.7mL,0.21mol), was then stirred at room temperature for 3 hoursThe above. After completion of the reaction, filtration was carried out, and the filtered solution was dried in vacuo to obtain (6-t-butoxyhexyl) dichloromethylsilane [ tBu-O- (CH)₂)₆SiMeCl₂](yield 84%). A solution of fluorenyllithium (4.82g,0.028 mol)/hexane (150mL) was slowly added to tBu-O- (CH) over a 2 hour period at-78 deg.C₂)₆SiMeCl₂(7.7g,0.028mol) in hexane (50 mL). Then, the white precipitate (LiCl) was filtered off, and the desired product was extracted with hexane. After removing all volatile substances from the hexane solution by vacuum drying, (6- (tert-butoxy) hexyl) fluorenylmethylsilane [ tBu-O- (CH) was obtained as a pale yellow oil₂)₆)SiMe(9-C₁₃H₁₀)]Compound (yield 99%).

Synthesis of (tert-butoxyhexyl) (cyclopentadienyl) (fluorenyl) methylsilane

THF solvent (50mL) was added to the above compound and reacted with C at room temperature₅H₅Li (2.0g,0.028mol)/THF (50mL) solution was reacted for 3 hours or more. After removing all volatiles from the reaction product by vacuum drying, the dried product was extracted with hexane to obtain the final ligand compound: (tert-butoxyhexyl) (cyclopentadienyl) (fluorenyl) methylsilane [ (tBu-O- (CH) as orange oil₂)₆)(CH₃)Si(C₅H₅)(9-C₁₃H₁₀)](yield 95%). The structure of the ligand is as follows¹H-NMR confirmed.

Synthesis of (tert-butoxyhexyl) (methyl) silyl (cyclopentadienyl) (fluorenyl) zirconium dichloride

Furthermore, 2 equivalents of n-BuLi were added to (tert-butoxyhexyl) (cyclopentadienyl) (fluorenyl) methylsilane [ (tBu-O- (CH) at a temperature of-78 deg.C₂)₆)(CH₃)Si(C₅H₅)(9-C1₃H₁₀)](12g,0.028mol)/THF (100 mL). After the addition was completed, the reaction temperature was raised to room temperature and carried out for 4 hours or more to obtain (tBu-O- (CH) as an orange solid₂)₆)(CH₃)Si(C₅H₅Li)(9-C₁₃H₁₀Li) dilithium salt (yield 81%). Thereafter, atZrCl was slowly added to a solution of dilithium salt (2.0g,4.5 mmol)/diethyl ether (30mL) at-78 deg.C₄(1.05g,4.50mmol) in diethyl ether (30 mL). The reaction was further carried out at room temperature for 3 hours. After removing all volatile materials in the obtained solution by vacuum drying, a dichloromethane solvent was added to the obtained oily liquid material, and filtration was performed to remove some solid materials. After drying the filtered solution under vacuum, hexane was added to induce precipitation. The resulting precipitate was washed several times with hexane. Then, rac- (tert-butoxyhexyl) (methyl) silyl (cyclopentadienyl) (fluorenyl) zirconium dichloride [ rac- (t-Bu-O- (CH) as a red solid ] was obtained₂)₆)(CH₃)Si(C₅H₄)(9-C₁₃H₉)ZrCl₂](yield 54%).

Comparative Synthesis example 2

Indene (5g,0.043mol) was dissolved in hexane (150mL) and mixed well. Thereafter, the temperature of the reaction mass was cooled to-30 ℃ and a 2.5M n-butyllithium (n-BuLi) hexane solution (17ml,0.043mol) was added dropwise to the reaction mass. Then, the reaction temperature was gradually raised to room temperature, followed by stirring at room temperature for 12 hours. The resulting white suspension was filtered through a glass filter to obtain a white solid compound. The white solid compound was sufficiently dried, and then, an indene lithium salt (yield: 99% yield) was obtained.

Cyclopentadienyl zirconium trichloride (Cp-ZrCl)₃2.24g,8.53mmol) was slowly dissolved in diethyl ether (30mL) and the reaction temperature was then cooled to-30 ℃. To a catalyst comprising CpZrCl₃To a diethyl ether solution of the above indene lithium salt (1.05g,8.53mmol) in diethyl ether (15mL) was added dropwise, followed by stirring overnight. Then, indenyl (cyclopentadienyl) zirconium dichloride [ indenyl (cyclopentadienyl) ZrCl ] was obtained₂](yield: 97%).

Comparative Synthesis example 3

Synthesis of (6-t-butoxyhexyl) dichloromethylsilane

100mL of t-butoxyhexylmagnesium chloride solution (0.14mol, ether) was added dropwise to 100mL of trichloromethylsilane solution (0.21mol, hexane) at-100 ℃ over 3 hours. Then, the reaction temperature was raised to room temperature, followed by stirring at room temperature for 3 hours.

After separating the transparent organic layer from the mixed solution, the separated transparent organic layer was vacuum-dried to remove excess trichloromethylsilane. Thus, transparent liquid (6-t-butoxyhexyl) dichloromethylsilane was obtained (yield 84%).

¹H NMR(500MHz,CDCl₃,7.24ppm):δ0.76(3H,s),1.11(2H,t),1.18(9H,s),1.32-1.55(8H,m),3.33(2H,t)。

Synthesis of (6- (tert-butoxy) hexyl) (4- (4- (tert-butyl) phenyl) -2-methyl-1H-inden-1-yl) (methyl) (2-isopropyl-4- (4- (tert-butyl) phenyl) -1H-inden-1-yl) silane

20g (76.222mmol) of 2-methyl-4- (4- (tert-butyl) phenyl) indene were dissolved in 640mL of a mixed solvent of hexane and methyl tert-butyl ether (MTBE) (Hex/MTBE 15/1 vol.). Thereafter, 33.5mL of n-BuLi (2.5M in hexane) was added dropwise to the solution at-20 ℃. After the resulting reaction mixture was stirred at room temperature for one day, 19.7g (72.411mmol) (6-t-butoxyhexyl) dichloromethylsilane (80.5 mL) solution in hexane was slowly added to the resulting reaction mixture at-20 ℃. Then, the resulting reaction mixture was stirred at room temperature for one day. After removing the volatile solvent from the resulting reaction mixture by vacuum drying, hexane was added to the dried reaction mixture and vacuum filtration was performed again. After drying the filtered solution, a silyl compound was obtained.

Meanwhile, in another flask, 22.1g (76.222mmol) of 2-isopropyl-4- (4- (tert-butyl) phenyl) indene and 136.5mg (1.525mmol) of CuCN were dissolved in 200mL of diethyl ether. Thereafter, 33.5mL of an n-butyllithium solution (2.5M in hexane) was added dropwise to the diethyl ether solution at-20 ℃. Then, after the resultant reaction mixture was stirred at room temperature for one day, the silane prepared above was dissolved in 180mL of diethyl ether and added to the resultant reaction mixture. Thereafter, the resulting reaction mixture was stirred at room temperature for one day, the organic material was extracted with water and MTBE, and dried in vacuo. Then, the reduced pressure dried product was purified by column chromatography to obtain the final ligand in 67% yield.

Synthesis of 6- (tert-butoxy) hexyl) (4- (4- (tert-butyl) phenyl) -2-methyl-1H-inden-1-yl) (methyl) (2-isopropyl-4- (4- (tert-butyl) phenyl) -1H-inden-1-yl) silane zirconium dichloride

1.00g (1.331mmol) of (6- (tert-butoxy) hexyl) (4- (4- (tert-butyl) phenyl) -2-methyl-1H-inden-1-yl) (methyl) (2-isopropyl-4- (4- (tert-butyl) phenyl) -1H-inden-1-yl) silane prepared above was dissolved in 33mL of diethyl ether, and then 1.1mL of an n-butyllithium solution (2.5M in hexane) was added dropwise to the above diethyl ether solution. After the resultant reaction mixture was stirred at room temperature for about 4 hours, 706mg (1.331mmol) of bis (N, N' -diphenyl-1, 3-malonylamino) zirconium dichloride bis (tetrahydrofuran) [ Zr (C)₅H₆NCH₂CH₂CH₂NC₅H₆)Cl₂(C₄H₅O)₂]A solution prepared by dissolving in 33mL of diethyl ether, followed by stirring for 1 day. Thereafter, the red reaction solution was cooled to-20 ℃, and 4 equivalents of 1M HCl diethyl ether solution were dropwise added to the cooled solution, and then the resulting solution was stirred at room temperature for 1 hour again. After filtration and vacuum drying, the solid obtained was dissolved in pentane and solid crystals were precipitated for 48 hours. After filtration under reduced pressure, the solid crystals were dried to obtain an orange transition metal compound, (6- (tert-butoxy) hexyl) (4- (4- (tert-butyl) phenyl) -2-methyl-1H-inden-1-yl) (methyl) (2-isopropyl-4- (4- (tert-butyl) phenyl) -1H-inden-1-yl) silane zirconium dichloride in a yield of 8% (racemic only).

¹H NMR(500MHz,CDCl₃,7.26ppm):δ1.05(3H,d),1.09(3H,d),1.20(3H,s),1.34(9H,s),1.50-1.93(10H,m),2.27-2.31(1H,m),3.37(2H,t),6.48(1H,s)6.98(1H,s),7.01(1H,s),7.09-7.12(2H,m),7.34-7.70(12H,m)。

< preparation of second metallocene Compound >

Synthesis example 3

Synthesis of 1-bromo-4- (tert-butoxymethyl) benzene

H is to be₂SO₄(1.47mL) and anhydrous MgSO₄(12.9g,107mmol) CH was added₂Cl₂(80mL), and then stirred at room temperature for 15 minutes. In another flask, 4-bromobenzyl alcohol (5.0g,26.7mmol) and tert-butanol (12.8mL,134mmol) were dissolved in CH₂Cl₂(30mL), and then the above mixture was added thereto. The mixture was then stirred at room temperature overnight and then saturated NaHCO was added₃. With anhydrous MgSO₄Water was removed, and the resulting solution was concentrated under reduced pressure and then purified by column chromatography (E/H ═ 1/20) to obtain 1-bromo-4- (tert-butoxymethyl) benzene (5.9g, 90%) as a white solid.

¹H NMR(500MHz,CDCl₃,7.24ppm):δ1.28(9H,s),4.39(2H,s),7.22(2H,d),7.44(2H,d)。

Synthesis of 7- ((4-tert-butoxymethyl) phenyl) -2-methyl-1H-indene

1-bromo-4- (tert-butoxymethyl) benzene (4.52g,18.6mmol) was dissolved in anhydrous THF (20mL) under argon (Ar). The temperature was lowered to-78 ℃ and an n-butyllithium solution (n-BuLi, 2.5M in hexane, 8.2mL) was added, followed by stirring at room temperature for 30 minutes. The temperature was again lowered to-78 ℃ and trimethyl borate (6.2mL,55.6mmol) was added, followed by stirring at room temperature overnight. Adding saturated NH to the reaction solution₄Cl solution (sat. nh)₄Cl), then extracted with MTBE. Adding anhydrous MgSO₄And water was removed by filtration. The solution was concentrated under reduced pressure and the subsequent reaction was carried out without further purification.

The compound obtained above was combined with 7-bromo-2-methyl-1H-indene (3.87g,18.6mmol) and Na₂CO₃(5.91g,55.8mmol) was addedToluene (40mL), H₂O (20mL) and EtOH (20mL) in a mixed solvent with stirring. To the above solution was added Pd (PPh)₃)₄(1.07g,0.93mmol), followed by stirring at 90 ℃ overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. With anhydrous MgSO₄And (4) removing water. The obtained solution was concentrated under reduced pressure, and then purified by column chromatography (E/H ═ 1/30) to obtain 7- ((4-tert-butoxymethyl) phenyl) -2-methyl-1H-indene (2.9g, 53%).

¹H NMR(500MHz,CDCl₃,7.24ppm):δ1.33(9H,s),2.14(3H,s),3.36(2H,s),4.50(2H,s),6.53(1H,s),7.11-7.45(7H,m)。

Synthesis of bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) dimethylsilane

7- ((4-tert-butoxymethyl) phenyl) -2-methyl-1H-indene (2.88g,9.85mmol) and CuCN (44mg,0.49mmol) were dissolved in toluene (18mL) and THF (2mL) under argon (Ar). The solution was cooled to-30 ℃ and n-BuLi (2.5M in hexanes, 4.1mL) was added slowly. After stirring at this temperature for about 20 minutes, the temperature was raised to room temperature and stirred for 2.5 hours. Dichlorodimethylsilane (0.59mL,4.89mmol) was added to the solution, followed by stirring at room temperature overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. The organic layer obtained was passed over anhydrous MgSO₄Dried to remove water and concentrated under reduced pressure, then purified by column chromatography (hexane) to obtain bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) dimethylsilane (2.95g, 93%) as a white solid.

¹H NMR(500MHz,CDCl₃,7.24ppm):δ-0.20(6H,s),1.35(18H,s),2.19(3H,s),2.25(3H,s),3.81(2H,s),4.53(4H,s),6.81(2H,s),7.18-7.52(14H,m)。

Synthesis of dimethylsilyl-bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) zirconium dichloride

Bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) -dimethyl-silane (2.0g,3.12mmol) was added under argon (Ar) to a 50mL Schlenk flask and dissolved by injection of diethyl ether (20 mL). The temperature is reduced to-78 ℃, and n-BuLi is added(2.5M in hexanes, 2.7mL) and then stirred at room temperature for 2 hours. Distilling the solvent under vacuum/reduced pressure, adding ZrCl into a glove box₄(THF)₂(1.18g,3.12mmol) and the temperature was lowered to-78 ℃. Diethyl ether (20mL) was added to the mixture, and then the temperature was raised to room temperature, followed by stirring overnight. The solvent was distilled under reduced pressure and dissolved in CH₂Cl₂To remove solids. The solution was concentrated under reduced pressure and the solid obtained was taken up in toluene and CH₂Cl₂Washed to obtain dimethylsilyl-bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) zirconium dichloride (260mg, 10%, r/m about 16/1) as a racemic yellow enriched solid.

¹H NMR(500MHz,CDCl₃,7.24ppm):δ1.28(18H,s),1.33(6H,s),2.24(6H,s),4.46(4H,s),6.93(2H,s),7.08–7.65(14H,m)。

Synthesis example 4

Synthesis of 1-bromo-4- (methoxymethyl) benzene

DMSO (117mL)/KOH (214mmol,12g) was added to the flask, 4-bromobenzyl alcohol (53.5mmol,10.0g) was added, and then stirring was carried out at room temperature for 1 hour. MeI (107mmol,6.6mL) was added to the reaction product, followed by stirring for 10 min. After the reaction was complete, the reaction mixture was poured into H₂In O, then with CH₂Cl₂And (4) extracting. The organic layer was dried over anhydrous MgSO₄Dried and then dried in vacuo to obtain 1-bromo-4-methoxymethyl benzene (10.6g, 99%).

¹H NMR(500MHz,CDCl₃,7.24ppm):δ3.41(3H,s),4.39(2H,s),7.11-7.53(4H,m)。

Synthesis of 7- (4-methoxymethyl) phenyl) -2-methyl-1H-indene

1-bromo-4- (methoxymethyl) benzene (9.3g,46.3mmol) was dissolved in anhydrous THF (40mL) under argon (Ar). The temperature was lowered to-78 ℃ and an n-butyllithium solution (n-BuLi, 2.5M in hexane, 20.4mL) was added, followed by stirring at room temperature for 30 minutes. The temperature was again lowered to-78 ℃ and trimethyl borate (15.5mL,139mmol) was added and then stirred at room temperature overnight. Adding saturated NH to the reaction solution₄Cl, then extracted with MTBE. Adding anhydrous MgSO₄And water was removed by filtration. The solution was concentrated under reduced pressure and the subsequent reaction was carried out without further purification.

The compound obtained above, 7-bromo-2-methyl-1H-indene (9.63g,46.3mmol) and Na₂CO₃(14.7g,139mmol) toluene (80mL), H₂O (40mL) and EtOH (40mL) in a mixed solvent with stirring. To the above solution was added Pd (PPh)₃)₄(1.07g,2.32mmol) and then stirred at 90 ℃ overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. With anhydrous MgSO₄And (4) removing water. The obtained solution was concentrated under reduced pressure, and then purified by column chromatography (E/H ═ 1/30) to obtain 7- (4- (methoxymethyl) phenyl) -2-methyl-1H-indene (6.9g, 60%).

¹H NMR(500MHz,CDCl₃,7.24ppm):δ2.15(3H,s),3.35(2H,s),3.38(3H,s),4.48(2H,s),6.55(1H,s),7.05-7.44(7H,m)。

Synthesis of bis (4- (4-methoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) dimethylsilane

7- (4-methoxymethyl) phenyl) -2-methyl-1H-indene (4.21g,16.8mmol) and CuCN (75mg,0.84mmol) were dissolved in toluene (36mL) and THF (4mL) under argon (Ar). The solution was cooled to-30 ℃ and n-BuLi (2.5M in hexanes, 7.4mL) was added slowly. After stirring at this temperature for about 20 minutes, the temperature was raised to room temperature, followed by stirring for 2.5 hours. Dichlorodimethylsilane (1.01mL,8.4mmol) was added to the solution, which was then stirred at room temperature overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. The organic layer obtained was passed over anhydrous MgSO₄Dried to remove water, concentrated under reduced pressure, and then purified by column chromatography (hexane) to obtain bis (4- (4-methoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) dimethylsilane (4.21g, 90%) as a white solid.

¹H NMR(500MHz,CDCl₃,7.24ppm):δ-0.21(6H,s),2.20(3H,s),2.23(3H,s),3.40(6H,s),3.82(2H,s),4.50(4H,s),6.79(2H,s),7.15-7.53(14H,m)。

Synthesis of dimethylsilyl-bis (4- (4-methoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) zirconium dichloride

Bis (4- (4-methoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) -dimethyl-silane (3.0g,5.39mmol) was added under argon (Ar) to a 50mL Schlenk flask and dissolved by injection of diethyl ether (30 mL). The temperature was lowered to-78 deg.C, n-BuLi (2.5M in hexanes, 4.7mL) was added, then stirred at room temperature for 2 hours. Distilling the solvent under reduced pressure, adding ZrCl into a glove box₄(THF)₂(2.04g,5.39mmol) and the temperature was lowered to-78 ℃. Diethyl ether (30mL) was added to the mixture, the temperature was raised to room temperature, and stirred overnight. The solvent was distilled under reduced pressure and dissolved in CH₂Cl₂To remove solids. The solution was concentrated under reduced pressure and the solid obtained was taken up in toluene and CH₂Cl₂Washed to obtain dimethylsilyl-bis (4- (4-methoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) zirconium dichloride (425mg, 11%, r/m about 10/1) as a racemic yellow enriched solid.

¹H NMR(500MHz,CDCl₃,7.24ppm):δ1.31(6H,s),2.22(6H,s),3.39(6H,s),4.43(4H,s),6.91(2H,s),7.09-7.64(14H,m)。

Synthesis example 5

Synthesis of 1-bromo-4- (tert-butoxymethyl) benzene

H is to be₂SO₄(1.47mL) and anhydrous MgSO₄(12.9g,107mmol) CH was added₂Cl₂(80mL), and then stirred at room temperature for 15 minutes. In another flask, 4-bromobenzyl alcohol (5.0g,26.7mmol) and tert-butanol (12.8mL,134mmol) were dissolved in CH₂Cl₂(30mL), and then the above mixture was added thereto. The mixture was then stirred at room temperature overnight and then saturated NaHCO was added₃. With anhydrous MgSO₄Remove water, andthe resulting solution was concentrated under reduced pressure, and then purified by column chromatography (E/H ═ 1/20) to obtain 1-bromo-4- (tert-butoxymethyl) benzene (5.9g, 90%) as a white solid.

Synthesis of 7- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-indene

The compound obtained above was combined with 7-bromo-2-methyl-1H-indene (3.87g,18.6mmol) and Na₂CO₃(5.91g,55.8mmol) toluene (40mL), H₂O (20mL) and EtOH (20mL) in a mixed solvent with stirring. To the above solution was added Pd (PPh)₃)₄(1.07g,0.93mmol), followed by stirring at 90 ℃ overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. With anhydrous MgSO₄And (4) removing water. The obtained solution was concentrated under reduced pressure, and then purified by column chromatography (E/H ═ 1/30) to obtain 7- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-indene (2.9g, 53%).

Synthesis of bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) diethylsilane

7- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-indene (2.88g,9.85mmol) and CuCN (44mg,0.49mmol) were dissolved in toluene (18mL) and THF (2) under argon (Ar)ml). The solution was cooled to-30 ℃ and n-BuLi (2.5M in hexanes, 4.1mL) was added slowly. After stirring at this temperature for about 20 minutes, the temperature was raised to room temperature and stirred for 2.5 hours. Dichlorodiethylsilane (0.73mL,4.89mmol) was added to the solution, which was then stirred at room temperature overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. The organic layer obtained was passed over anhydrous MgSO₄Dried to remove water, concentrated under reduced pressure, and then purified by column chromatography (hexane) to obtain bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) diethylsilane (2.95g, 93%) as a white solid.

Synthesis of diethylsilyl-bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) zirconium dichloride

Bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) -diethyl-silane (2.0g,3.12mmol) was charged to a 50mL Schlenk flask under argon (Ar) and dissolved by injection of diethyl ether (20 mL). The temperature was lowered to-78 deg.C, n-BuLi (2.5M in hexanes, 2.7mL) was added, then stirred at room temperature for 2 hours. Distilling the solvent under vacuum/reduced pressure, adding ZrCl into a glove box₄(THF)₂(1.18g,3.12mmol) and the temperature was lowered to-78 ℃. Diethyl ether (20mL) was added to the mixture, and then the temperature was raised to room temperature, followed by stirring overnight. The solvent was distilled under reduced pressure and dissolved in CH₂Cl₂To remove solids. The solution was concentrated under reduced pressure and the solid obtained was taken up in toluene and CH₂Cl₂Washed to obtain diethylsilyl-bis (4- (4-tert-butoxymethyl) phenyl) -2-methyl-1H-inden-1-yl) zirconium dichloride (260mg, 10%, r/m about 16/1) as a racemic-rich yellow solid.

Comparative Synthesis example 4

Synthesis of methyl (6-t-butoxyhexyl) dichlorosilane

To a 10L reactor was added 50g of Mg(s) at room temperature followed by 300mL of THF. 0.5g I was added₂And the reactor temperature was maintained at 50 ℃. After the reactor temperature had stabilized, 250g of 6-t-butoxyhexyl chloride (6-t-butoxyhexyl chloride) was added to the reactor at a rate of 5mL/min using a feed pump. With the addition of 6-tert-butoxyhexyl chloride, an increase in the temperature of the reactor of about 4 ℃ to 5 ℃ was observed. 6-t-butoxyhexyl chloride was continuously added while the mixture was stirred for 12 hours to obtain a black reaction solution. 2mL of the black solution was taken, and water was added thereto to obtain an organic layer. By passing¹H-NMR confirmed that the organic layer was 6-t-butoxyhexane. This confirmed that the Grignard reaction proceeded well. Thus, 6-t-butoxyhexylmagnesium chloride was synthesized.

500g of MeSiCl₃And 1L of THF were added to the reactor, and the reactor temperature was then cooled to-20 ℃. 560g of the previously synthesized 6-t-butoxyhexylmagnesium chloride was added to the reactor at a rate of 5mL/min using a feed pump. After completion of the grignard feed, the mixture was stirred for 12 hours while the reactor temperature was slowly raised to room temperature and it was confirmed that white MgCl was formed₂And (3) salt. 4L of hexane was added thereto and the salt was removed by labdori to obtain a filtered solution. After the filtered solution was added to the reactor, hexane was removed at 70 ℃ to obtain a pale yellow liquid. The obtained liquid was confirmed by 1H-NMR to be the desired methyl (6-t-butoxyhexyl) dichlorosilane.

¹H-NMR(500MHz,CDCl₃):δ3.3(t,2H),1.5(m,3H),1.3(m,5H),1.2(s,9H),1.1(m,2H),0.7(s,3H)。

Synthesis of methyl (6-t-butoxyhexyl) (tetramethylcyclopentadienyl) -t-butylaminosilane

1.2mol (150g) of tetramethylcyclopentadiene and 2.4L of THF were charged into a reactor, and then the reactor temperature was cooled to-20 ℃. Make it480mL of n-BuLi (2.5M in hexane) were added to the reactor at a rate of 5mL/min using a feed pump. After the addition of n-BuLi, the mixture was stirred for 12 hours while the reactor temperature was slowly raised to room temperature. Thereafter, an equivalent amount of methyl (6-t-butoxyhexyl) dichlorosilane (326g,350mL) was rapidly added to the reactor. The mixture was stirred for 12 hours while the reactor temperature was slowly raised to room temperature. Then, the reactor temperature was cooled again to 0 ℃ and 2 equivalents of t-BuNH were added₂. The mixture was stirred for 12 hours while the reactor temperature was slowly raised to room temperature. Then, THF was removed and 4L of hexane was added to obtain a filtered solution with salts removed by labdori. The filtered solution was again added to the reactor, and hexane was removed at 70 ℃ to obtain a yellow solution. By passing¹H-NMR confirmed methyl (6-t-butoxyhexyl) (tetramethyl CpH) t-butylaminosilane.

Synthesis of (tert-butoxyhexyl) methylsilyl (tetramethylcyclopentadienyl) (tert-butylamino) titanium dichloride

At-78 deg.C, 10mmol TiCl₃(THF)₃The ligand dilithium salt, synthesized from a ligand of n-BuLi and dimethyl (tetramethyl CpH) tert-butylaminosilane in THF solution, was added rapidly. The reaction solution was stirred for 12 hours while the temperature was slowly raised from-78 ℃ to room temperature. Then equivalent amounts of PbCl were added at room temperature₂(10mmol) and the mixture was stirred for 12 hours to obtain a bluish dark black solution. After THF was removed from the resultant reaction solution, hexane was added to filter the product. Removing hexane from the filtered solution, and then passing¹H-NMR confirmed the product as the desired tBu-O- (CH)₂)₆](CH₃)Si(C₅(CH₃)₄)(tBu-N)TiCl₂。

¹H-NMR(500MHz,CDCl₃):δ3.3(s,4H),2.2(s,6H),2.1(s,6H),1.8-0.8(m),1.4(s,9H),1.2(s,9H),0.7(s,3H)。

Comparative Synthesis example 5

Synthesis of 7-phenyl-2-methyl-1H-indene

Bromobenzene (2.92g,18.6mmol) was dissolved in anhydrous THF (20mL) under argon (Ar). The temperature was lowered to-78 ℃ and an n-butyllithium solution (n-BuLi, 2.5M in hexane, 8.2mL) was added, followed by stirring at room temperature for 30 minutes. The temperature was again lowered to-78 ℃ and trimethyl borate (6.2mL,55.6mmol) was added, followed by stirring at room temperature overnight. Adding saturated NH to the reaction solution₄Cl solution (sat. nh)₄Cl), then extracted with MTBE. Adding anhydrous MgSO₄And water was removed by filtration. The solution was concentrated under reduced pressure and the subsequent reaction was carried out without further purification.

The compound obtained above was combined with 7-bromo-2-methyl-1H-indene (3.87g,18.6mmol) and Na₂CO₃(5.91g,55.8mmol) toluene (40mL), H₂O (20mL) and EtOH (20mL) in a mixed solvent with stirring. To the above solution was added Pd (PPh)₃)₄(1.07g,0.93mmol), followed by stirring at 90 ℃ overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. With anhydrous MgSO₄And (4) removing water. The obtained solution was concentrated under reduced pressure, and then purified by column chromatography (E/H ═ 1/30) to obtain 7-phenyl-2-methyl-1H-indene (2.9g, 53%).

Synthesis of bis (4-phenyl-2-methyl-1H-inden-1-yl) dimethylsilane

7-phenyl-2-methyl-1H-indene (2.02g,9.85mmol) and CuCN (44mg,0.49mmol) were dissolved in toluene (18mL) and THF (2mL) under argon (Ar). The solution was cooled to-30 ℃ and n-BuLi (2.5M in hexanes, 4.1mL) was added slowly. After stirring at this temperature for about 20 minutes, the temperature was raised to room temperature and stirred for 2.5 hours. Dichlorodimethylsilane (0.59mL,4.89mmol) was added to the solution, followed by stirring at room temperature overnight. After completion of the reaction, MTBE and water were added and the organic layer was separated. The organic layer obtained was passed over anhydrous MgSO₄Dried to remove water, concentrated under reduced pressure, and then purified by column chromatography (hexane) to obtain bis (4-phenyl-2-methyl-1H-inden-1-yl) -dimethylsilane as a white solid.

Synthesis of dimethylsilyl-bis (4-phenyl-2-methyl-1H-inden-1-yl) zirconium dichloride

Bis (4-phenyl-2-methyl-1H-inden-1-yl) -dimethylsilane (2.0g,3.12mmol) was charged to a 50mL Schlenk flask under argon (Ar) and dissolved by injection of diethyl ether (20 mL). The temperature was lowered to-78 deg.C, n-BuLi (2.5M in hexanes, 2.7mL) was added, then stirred at room temperature for 2 hours. Distilling the solvent under vacuum/reduced pressure to obtain ZrCl₄(THF)₂(1.18g,3.12mmol) was placed in a glove box and the temperature was reduced to-78 ℃. Diethyl ether (20mL) was added to the mixture, and then the temperature was raised to room temperature, followed by stirring overnight. The solvent was distilled under reduced pressure and dissolved in CH₂Cl₂To remove solids. The solution was concentrated under reduced pressure and the solid obtained was taken up in toluene and CH₂Cl₂Washed to obtain dimethylsilyl-bis (4-phenyl-2-methyl-1H-inden-1-yl) zirconium dichloride (260mg, 10%, r/m about 16/1) as a racemic yellow enriched solid.

< preparation of Supported catalyst >

Example 1: preparation of composite load type metallocene catalyst

First, silica (SP 952 manufactured by Grace Davison) was dehydrated and dried under vacuum at a temperature of 250 ℃ for 12 hours to prepare a carrier.

Then, 3.0kg of the toluene solution was added to a 20L high pressure stainless steel (sus) reactor, 1000g of silica (Grace Davison, SP952) prepared in advance was added thereto, and the reactor temperature was raised to 40 ℃ while stirring. After the silica was sufficiently dispersed for 60 minutes, 8kg of 10 wt% Methylaluminoxane (MAO)/toluene solution was added, and the mixture was slowly reacted for 12 hours with stirring at 200 rpm. Thereafter, the temperature of the reactor was raised to 60 ℃, followed by addition of 0.1mmol of the first metallocene compound prepared in Synthesis example 1 dissolved in toluene in a solution state. Then, the reaction mixture was reacted at 50 ℃ for 2 hours with stirring at 200 rpm.

After the completion of the reaction, 0.05mmol of the second metallocene compound prepared in Synthesis example 3 was dissolved in toluene and reacted at 50 ℃ for 2 hours with stirring at 200 rpm.

When the reaction was completed, the stirring was stopped, and the reaction solution was separated after standing for 30 minutes. After washing with sufficient toluene, 50mL of toluene was added again. Then, stirring was stopped after 10 minutes, and washing was performed with a sufficient amount of toluene to remove compounds not participating in the reaction. Thereafter, 3.0kg of hexane was added to the reactor and stirred, and the hexane slurry was transferred to a filter for filtration.

The composite supported metallocene catalyst was obtained by drying once at room temperature under reduced pressure for 5 hours and then drying twice at 50 ℃ under reduced pressure for 4 hours.

Example 2: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.2mmol of the metallocene compound prepared in Synthesis example 1 and 0.05mmol of the metallocene compound prepared in Synthesis example 4 were added, respectively.

Example 3: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.08mmol of the metallocene compound prepared in Synthesis example 2 and 0.08mmol of the metallocene compound prepared in Synthesis example 3 were added, respectively.

Example 4: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.1mmol of the metallocene compound prepared in Synthesis example 1 and 0.05mmol of the metallocene compound prepared in Synthesis example 5 were added, respectively.

Comparative example 1: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.1mmol of the metallocene compound prepared in comparative Synthesis example 1 and 0.05mmol of the metallocene compound prepared in Synthesis example 3 were added, respectively.

Comparative example 2: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.1mmol of the metallocene compound prepared in comparative Synthesis example 2 and 0.05mmol of the metallocene compound prepared in Synthesis example 3 were added, respectively.

Comparative example 3: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.1mmol of the metallocene compound prepared in comparative Synthesis example 3 and 0.05mmol of the metallocene compound prepared in Synthesis example 3 were added, respectively.

Comparative example 4: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that 0.1mmol of the metallocene compound prepared in Synthesis example 2 and 0.05mmol of the metallocene compound prepared in comparative Synthesis example 4 were added, respectively.

Comparative example 5: preparation of composite load type metallocene catalyst

A composite supported metallocene catalyst was prepared in the same manner as in example 1, except that the metallocene compound (catalyst G) prepared in comparative synthesis example 5 was added as a second precursor, i.e., a second metallocene compound, in place of the metallocene compound prepared in synthesis example 3.

< test example >

Test example 1: preparation of polyethylene

Ethylene-1-hexene was slurry-polymerized in the presence of the supported catalyst prepared in one of the examples and comparative examples under the conditions shown in table 1 below.

At this time, a continuous polymerization reactor of a slurry loop process (slurry loop process) using isobutane (i-C4) was used, the reactor volume was 140L, and the reaction flow rate was about 7 m/s. The gases required for the polymerization (ethylene, hydrogen) and 1-hexene as comonomer were added continuously and the flow rates were adjusted according to the desired product. The concentration of all gases and comonomer (1-hexene) was confirmed by on-line gas chromatography. The supported catalyst was introduced into the isobutane slurry, the reactor pressure was maintained at about 40 bar, and the polymerization temperature was about 85 ℃.

[ Table 1]

Test example 2: evaluation of the activity, Process stability and physical Properties of the composite Supported catalyst

The activities, process stabilities, and physical properties of the polyethylene copolymers of examples and comparative examples were measured by the following methods, and the results are shown in table 2 below.

(1) Activity (kg PE/g cat hr)

It is calculated as the ratio of the weight of the polyethylene copolymer produced per unit time (h) (kg PE) to the weight of the supported catalyst used (g. Cat).

(2) Melt index (g/10min, MI)

Melt Index (MI)_2.16) Measured at 190 ℃ under a 2.16kg load according to ASTM D1238 and expressed as the weight (g) of polymer melted for 10 minutes.

(3) Density of

Density (g/cm) was measured according to ASTM D792³)。

(4) Bulk Density (BD)

Bulk density was measured according to ASTM D1895.

(5) Process stability depending on whether fouling occurs or not

In the process for producing the polyethylene copolymer, it was examined whether or not fouling occurred, that is, whether or not solid products and the like were tangled on the inner devices and the wall surfaces of the reactor. Thereafter, when no fouling occurred, the process stability was evaluated as "good". On the other hand, when fouling occurred, the process stability was evaluated as "poor". The results are shown in table 2 below.

(6) Dart impact strength

A polyethylene copolymer film (BUR 2.3, film thickness 48 to 52 μm) was prepared using a film coater, and then the dart impact strength of each film sample was measured 20 times or more in accordance with ASTM D1709[ method A ], and the average value was taken.

[ Table 2]

As shown in table 2, it can be seen that, compared to the composite supported catalysts of comparative examples 1 to 5, the examples of the present invention ensure excellent process stability and high polymerization activity in ethylene polymerization while having high comonomer incorporation performance due to the use of the specific composite supported catalysts of examples 1 to 4. In addition, it can be seen that embodiments of the present invention can provide a low density polyethylene copolymer for preparing a film having excellent processability as well as high mechanical properties and dart impact resistance.

Claims

1. A composite supported metallocene catalyst comprises

At least one first metallocene compound selected from compounds represented by the following chemical formula 1;

at least one second metallocene compound selected from compounds represented by the following chemical formula 2; and

a support supporting a first metallocene compound and a second metallocene compound:

[ chemical formula 1]

(Cp¹R^a)_n(Cp²R^b)M¹Q¹ _3-n

In the chemical formula 1, the first and second,

M¹is a group 4 transition metal;

R^aand R^bAre identical or different from each other and are each independently hydrogen, C_1-20Alkyl radical, C_1-20Alkoxy radical, C_2-20Alkoxyalkyl group, C_6-20Aryl radical, C_6-20Aryloxy groupBase, C_2-20Alkenyl radical, C_7-40Alkylaryl group, C_7-40Arylalkyl radical, C₈-₄₀Arylalkenyl or C_2-10Alkynyl with the proviso that R^aAnd R^bIs not hydrogen;

n is 1 or 0;

[ chemical formula 2]

In the chemical formula 2, the first and second organic solvents,

M²is a group 4 transition metal;

a is carbon (C), silicon (Si) or germanium (Ge);

D¹and D²Is oxygen;

R¹and R²Are identical to or different from each other and are each independently C_1-20Alkyl radical, C_2-20Alkenyl radical, C_6-20Aryl radical, C₇-₄₀Alkylaryl or C_7-40An arylalkyl group; and is

2. The hybrid supported metallocene catalyst of claim 1, wherein

M¹Is zirconium (Zr) or hafnium (Hf),

Cp¹and Cp²Each independently is a cyclopentadienyl, indenyl, or fluorenyl group;

R^aand R^bEach independently is hydrogen, C_1-6Straight or branched alkyl, C_2-6Alkynyl, substituted by C_1-6C of alkoxy_1-6Alkyl, substituted by C_6-12C of aryl radicals_1-6Alkyl, or C_6-12Aryl with the proviso that R^aAnd R^bIs not hydrogen; and is

Q¹Each independently is halogen.

3. The composite supported metallocene catalyst according to claim 1, wherein the first metallocene compound is represented by any one of the following structural formulae:

4. the hybrid supported metallocene catalyst of claim 1, wherein

M²Is zirconium (Zr) or hafnium (Hf),

a is silicon (Si), and

X¹and X²Each independently is halogen.

5. The hybrid supported metallocene catalyst of claim 1, wherein

L¹And L²Each independently is C_1-3An alkylene group;

R¹and R²Each independently is C_1-6Straight or branched alkyl or C_6-12And (4) an aryl group.

6. The composite supported metallocene catalyst of claim 1, wherein R³And R⁴Each independently is C_1-6An alkyl group.

7. The composite supported metallocene catalyst of claim 1, wherein the second metallocene compound is represented by any one of the following structural formulae:

8. the composite supported metallocene catalyst of claim 1, wherein the first metallocene compound and the second metallocene compound are supported at a molar ratio of 0.3:1 to 4: 1.

9. The composite supported metallocene catalyst according to claim 1, wherein the support contains hydroxyl groups and siloxane groups on the surface thereof.

10. The composite supported metallocene catalyst of claim 9, wherein the carrier is at least one selected from the group consisting of silica, silica-alumina and silica-magnesia.

11. A method for preparing a polyethylene copolymer comprising the step of copolymerizing ethylene and an α -olefin in the presence of the composite supported metallocene catalyst of claim 1.

12. The method for preparing a polyethylene copolymer according to claim 11, wherein the copolymerization step is performed by reacting the α -olefin in an amount of 0.45 mol or less based on 1mol of the ethylene.

13. The method of preparing a polyethylene copolymer according to claim 11, wherein the α -olefin is at least one selected from the group consisting of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-eicosene.

14. A polyethylene copolymer obtained by the process of claim 11.

15. The polyethylene copolymer according to claim 14, wherein the polyethylene copolymer is an ethylene-1-hexene copolymer.

16. The polyethylene copolymer of claim 14, wherein the Melt Index (MI) is measured according to ASTM D1238_2.16At 190 ℃ under a 2.16kg load) of 0.5g/10min to 2.0g/10 min.

17. The polyethylene copolymer according to claim 14, wherein the bulk density measured according to ASTM D1895 is 0.2g/mL or more.

18. The polyethylene copolymer according to claim 14, wherein a dart impact strength of a polyethylene copolymer film (BUR of 2.3 and film thickness of 48 μm to 52 μm) prepared using a film applicator measured according to ASTM D1709 is 1200g or more.