KR20000026438A - Metallocene catalyst for preparing polyethylene and process for preparing polyethylene using catalyst - Google Patents

Abstract

PURPOSE: A catalyst is provided which has a good thermal stability. A polyethylene is also provided which has a uniform composition and molecular distribution degree by using the catalyst. CONSTITUTION: A metallocene catalyst of formula 1 and 2 is provided, wherein M is transition metal selected from 3- 10 group and lanthanide metal; Cp is cyclopentanyl; D is N or P; LB is Lewis base electron donor selected from OR, SR, PR2 or NR2; LA is organic compound Lewis acid selected from trialkyl aluminum, dialkyl haloaluminum, alkyl dihaloaluminum, dialkyl magnesium and alkyl halomagnesium; B is cross linking group selected from SiR2, CR2, SiR2SiR2, CR2CR2, CR=CR, CR2SiR2, GeR2, BR2; L is one or two substituted group selected from halogen, alkyl, allyl, sillyl, amine, amide, allyloxy, alkoxy, haloalkyl and haloallyl; R is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, cyclohexyl, dicyclohexyl methyl, phenyl, methyl phenyl and adamantyl. Polyethylene is prepared at 0-300°C, 1-1,000 atm in the presence of the metallocene catalyst, and methyl aluminoxane, alkyl haloaluminum or boron organic amine as a co catalyst, 1-100 mole ratio of alkyl aluminum to remove impurity of monomer and solvent.

Description

Metallocene catalyst for producing polyethylene and method for producing polyethylene using the same

The present invention relates to a metallocene catalyst for producing polyethylene and a method for producing polyethylene using the same, and more particularly, to a metallocene catalyst used as a catalyst in homopolymerization of ethylene or copolymerization of ethylene and α-olefin. And it relates to a method for producing a polyethylene with a uniform composition distribution using the same.

So far, in the preparation of homopolymers of ethylene or copolymers of ethylene and α-olefins, so-called Ziegler-Natta catalysts generally composed of a main catalyst component of a titanium or vanadium compound and a promoter component of an alkylaluminum compound catalyst system is used. Although the Ziegler-Natta catalyst system exhibits high activity against ethylene polymerization, the molecular weight distribution of the resulting polymer is generally wide due to the heterogeneous catalytic activity point, and the composition distribution is not uniform especially in the copolymer of ethylene and α-olefin. There are disadvantages.

Recently, a so-called metallocene catalyst system has been developed, which is composed of a metallocene compound of a periodic table group 4A transition metal such as Ti, Zr, Hf, and methylaluminoxane (hereinafter referred to as "MAO") as a promoter. Since the metallocene catalyst system is a homogeneous catalyst having a single catalytic activity point, the metallocene catalyst system has a characteristic of producing polyethylene having a narrower molecular weight distribution and a very uniform composition distribution than the conventional Ziegler-Natta catalyst system. For example, European Patent Nos. 320762 and 3726325, Japanese Patent Nos. 63092621, 02084405, and 032347 describe Cp ₂ TiCl ₂ , Cp ₂ ZrCl ₂ , Cp ₂ ZrMeCl, Cp ₂ ZrMe ₂ , Ethylene It is disclosed that by activating a metallocene compound such as (IndH ₄ ) ₂ ZrCl ₂ with a promoter MAO, ethylene can be polymerized with high activity to produce polyethylene having a molecular weight distribution (Mw / Mn) in the range of 1.5 to 2.0. have.

However, in the catalyst system, it is difficult to obtain a polymer having a sufficiently high molecular weight, and in particular, when applied to a solution polymerization method carried out at a high temperature of 140 ° C. or higher, the polymerization activity and molecular weight are drastically reduced, which is inappropriate to prepare a high molecular weight polymer. There is this.

In order to overcome this problem, the present inventors have conducted extensive research, and thus, when homopolymerization of ethylene or copolymerization of ethylene and α-olefin, the thermal stability of the catalyst is excellent, so that it can be effectively used in a solution polymerization process performed at high temperature. The catalyst was developed, and it was found that the catalyst can be produced in a high yield using polyethylene having a uniform composition distribution and controlling molecular weight and molecular weight distribution, and the present invention has been completed based on this.

Accordingly, it is an object of the present invention to provide a catalyst which is excellent in thermal stability and is effective in a high temperature solution polymerization process.

Still another object of the present invention is to provide a method for producing a high molecular weight polyethylene having a uniform composition distribution and controlling physical properties such as molecular weight and molecular weight distribution using the catalyst.

The catalyst according to the present invention for achieving the above object is a geometrically constrained metallocene catalyst represented by the following formula (1) or (2).

Here, M is one transition metal selected from the group consisting of Group 3, Group 4-10, and lanthanide-based metal of the periodic table, Cp is a cyclopentadienyl derivative capable of π-bond with M, D is is nitrogen or phosphorus element, LB is ^{oR *, SR *, PR *} 2, and NR ^* ₂ is a Lewis base electron donor substituents selected from the group consisting of, LA is a trialkyl aluminum, an aluminum alkyl di di alkylhalo One organometallic compound Lewis acid selected from the group consisting of haloaluminum, dialkylmagnesium, and alkylhalo magnesium, B is SiR ^* ₂ , CR ^* ₂ , SiR ^* ₂ SiR ^* ₂ , CR ^* ₂ CR ^* ₂ , CR ^* = CR ^* , CR ^* ₂ SiR ^* ₂ , GeR ^* ₂ , BR ^* ₂ , and BR ^* ₂ , one crosslinking group selected from the group consisting of halogen having a total number of atoms of 20 or less in addition to hydrogen Group, alkyl group, allyl group, silyl group, amine group, amide group, allyl group, al Group, wherein one or more than one substituent selected from a haloalkyl group, a haloalkoxy group consisting allyl, R ^* is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert- butyl, cyclohexyl, dicyclohexyl methyl, phenyl , Methylphenyl, and adamantyl.

A method for producing polyethylene for achieving another object of the present invention is a main catalyst at the time of homopolymerization of ethylene or copolymerization of ethylene and α-olefin, under a polymerization temperature of 0 to 300 ° C. and ethylene pressure of 1 to 1000 atm. The metallocene catalyst consisting of the compound of Formula 1 or 2, as a promoter is one catalyst selected from the group consisting of methyl aluminoxane, alkyl halo aluminum, and boron organic compound-based anion, monomer or at the time of polymerization Alkyl aluminum is added in the range of 1-100 molar ratio with respect to a catalyst in order to remove the impurity contained in a solvent.

1 is a molecular structure diagram of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) Ti (NMe ₂ ) ₂ , which is a metallocene catalyst according to one embodiment of the present invention,

FIG. 2 is a molecular structure diagram of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiCl ₂ as a metallocene catalyst according to another embodiment of the present invention.

3 is a molecular structure diagram of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) (AlMe ₃ ) TiMe ₂ as a metallocene catalyst according to another embodiment of the present invention,

4 is a molecular structure diagram of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiMe ₂ which is a metallocene catalyst according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

As shown in Formula 1, the catalyst of the present invention is an organic metal coordinated with the central metal element (M), which is a Group 4A transition metal, by adding an electron donating substituent, that is, Lewis base (LB), to the components of the geometric ligand It consists of compound (L). In addition, as shown in the following Chemical Formula 2, another catalyst of the present invention provides an appropriate amount of Lewis acid group (LA) to the Lewis base substituent in order to control the degree of electron donation from the compound of Chemical Formula 1 to the central metal (M). It consists of organometallic compounds.

Chemical Formula 1 Chemical Formula 2

Here, M is one transition metal selected from the group consisting of Groups 3, 4 to 10, and lanthanide-based metals of the periodic table, preferably titanium, zirconium and hafnium.

Cp is a cyclopentadienyl derivative capable of π-bonding with a central metal (M), more preferably cyclopentadienyl, methylcyclopentadienyl, dimethylcyclopentadienyl, tetramethylcyclopentadienyl , Butylcyclopentadienyl, t-butylmethylcyclopentadienyl, trimethylsilylcyclopentadienyl, indenyl, methylindenyl, and florenyl.

D is one element selected from nitrogen or phosphorous, LB is a Lewis base electron donor substituent OR ^* , SR ^* , PR ^* ₂ , or NR ^* ₂ , which possess one or more unbonded electron pairs and interact with the central metal R ^* is an alkyl group having 1 to 20 carbon atoms, an allyl group, a silyl group, a halogenated alkyl group, or an allyl group. LA is also a Lewis acid, preferably an organometallic compound selected from the group consisting of trialkylaluminum, dialkylhaloaluminum, alkyldihaloaluminum, and dialkylmagnesium, alkylhalomagnesium.

B is selected from the group consisting of SiR ^* ₂ , CR ^* ₂ , SiR ^* ₂ SiR ^* ₂ , CR ^* ₂ CR ^* ₂ , CR ^* = CR ^* , CR ^* ₂ SiR ^* ₂ , GeR ^* ₂ , and BR ^* ₂ One bridging group. R ^* is an alkyl group having 1 to 20 carbon atoms, allyl group, silyl group, halogenated alkyl group, allyl group. Specific examples thereof include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, cyclohexyl, dicyclohexylmethyl, phenyl, methylphenyl and adamantyl.

L is a core metal from an anion or Lewis salt group consisting of halogen, alkyl, allyl, silyl, amine, amide, allyl, alkoxy, haloalkyl and haloallyl groups other than hydrogen The oxidation of is one or two substituents selected according to. More preferably, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, tert-butyl group, cyclohexyl group, dicyclohexyl methyl group, phenyl group, methylphenyl group, benzyl group, chloride group, dimethyl Amine group, diethylamide group, diphenylamide group, dibenzylamide group, dihexylamide group, methylethylamide group, methylphenylamide group, methylbenzylamide group, methylhexylami group, phenylbenzylamide group, phenylhexyl Ami groups, benzyl hexylamide groups, trimethylsilyl groups, triethylsilyl groups, methoxy groups, ethoxy groups, propoxy groups, isopropoxy groups, butoxy groups, isobutoxy groups, and the like.

Since each component and intermediate products used to synthesize the catalyst component of the present invention easily reacts with various impurities such as oxygen and moisture, it is necessary to use reagents and solvents from which these impurities have been completely removed. It should proceed under an inert gas atmosphere such as nitrogen or argon.

First, in order to synthesize a ligand necessary for synthesizing the catalyst, typically a compound of CpLi and R²R³SiX₂ Or R²R³CX₂One compound selected from the group consisting of quantitatively reacted at -78 ~ 50 ℃ to separate the product, and then to the separated product typically⁴R⁵NCH₂NR⁶R⁷, NH₂NR⁴R⁵, NH₂PR⁴R⁵, PH₂NR⁴R⁵, And PH₂PR⁴R⁵A ligand compound is synthesized by reacting and separating one compound selected from the group consisting of at a molar ratio of 1: 2 at -78 to 50 ° C. Wherein Cp is a cyclopentadienyl derivative, X is selected from Cl or Br, and R is^One, R², R³, R⁴, R⁵, R⁶, R⁷Are the same or different from each other hydrogen or a hydrocarbon radical of 1 to 20 carbon atoms. Diethyl ether, tetrahydrofuran (THF), normal pentane, normal hexane, toluene, benzene, dichloromethane, etc. can be used for each reaction.

The ligand compound synthesized above and an n-BuLi or Grignard reagent, for example, one selected from the group consisting of BuMgCl, EtMgCl, and MeMgCl, are reacted at -78 to 50 ° C. at a molar ratio of 1: 2 to anionization. And then reacted with a compound represented by MCl _x (6-x) THF at -78 to 50 ° C in a 1: 1 molar ratio. Here, M is Ti, Zr or Hf and is an integer of x = 3 or 4. Subsequently, the product is immersed in diethyl ether or normal pentane to recrystallize the solution portion dissolved therein and separated to synthesize a compound represented by the following Chemical Formula 3. Formula 1 is represented by the following formula (3).

In another method, the ligand compound synthesized above and the compound represented by ML ₄ are reacted in a molar ratio of 1: 1 at 0 to 200 ° C. without a solvent, and then extracted by sublimation crystallization under reduced pressure to be represented by Formula 1 above. The compound which becomes is synthesize | combined. Here, M is Ti, Zr or Hf, L is NR ⁸ R ⁹ , PR ⁸ R ⁹ , OR, or SR, R, R ⁸ , and R ⁹ is an alkyl or aryl group having 1 to 20 carbon atoms.

When the compound represented by Chemical Formula 1 is reacted with aluminum alkyl or magnesium alkyl at −78 to 50 ° C., the compound represented by Chemical Formula 2 may be synthesized.

The catalyst component or structural analysis synthesized by the method described above may use ¹³ C-NMR, ¹ H-NMR or single crystal structure analysis.

Method for producing polyethylene using the prepared catalyst is as follows.

Polymerization Method

When homopolymerization of ethylene or copolymerization of ethylene and α-olefin using the catalyst described above, gas phase polymerization or liquid phase polymerization can generally be used. However, the catalyst component is not supported on a solid carrier, but in solution state. In order to use, the liquid-phase polymerization method is more preferable. In the liquid phase polymerization, the catalyst is used as the main catalyst in the presence of a suitable organic solvent, and the cocatalyst is brought into contact with the reaction monomer.

Preferred organic solvents for the present invention are hydrocarbons having 3 to 20 carbon atoms, specific examples of which are butane, isobutane, pentane, hexane, heptane, octane, nonane, decane, dodecane, cyclohexane, methylcyclohexane, benzene, toluene, And xylene and the like.

In the production of high density polyethylene, ethylene is used alone as a monomer, and the pressure of ethylene suitable for the present invention is 1 to 1000 atm, and more preferably 10 to 100 atm. If the pressure of ethylene is less than 1 atmosphere, the production yield is lowered. If it exceeds 1000 atmospheres, production of high density polyethylene is impossible.

In the production of low density polyethylene, an olefin having 3 to 18 carbon atoms is used as a co-monomer together with ethylene, and preferably propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 1-octadecene and the like. Preferable pressure of ethylene is the same as in the production of the high density polyethylene, and the amount of the α-olefin is 0.01 to 100 times the weight of ethylene, more preferably 0.1 to 10 times.

According to the present invention, the compounds represented by the above formulas (1) and (2) are used as the main catalyst and the cocatalyst required therefor is one selected from the group consisting of methyl aluminoxane (MAO), alkyl haloaluminum or boron organic compound-based anions. If L, which is one of the components of the compounds represented by Formulas 1 and 2, is one of halogen or an alkyl group, MAO is used as a cocatalyst, and the appropriate molar concentration of the main catalyst to the promoter is not particularly limited, but The range of the cocatalyst ratio (Al / Ti molar ratio) is preferably in the range of 10 to 10000, more preferably in the range of 100 to 1000. If the ratio is less than 10, the catalyst is not activated and ethylene polymerization does not occur. If the ratio exceeds 10000, the excess polyethylene residue may be included in the produced polyethylene.

When L is an amide or an alkoxy group, one alkyl haloaluminum selected from the group consisting of trimethylaluminum, triethylaluminum, diethylchloroaluminum, tributylaluminum, triisobutylaluminum and the like is used as a promoter. The molar concentration ratio (Al / Ti molar ratio) of the promoter to the main catalyst is 1 to 1000, much less than when using MAO, and preferably 5 to 500 times. If the ratio is less than 1, the catalyst is not activated and there is almost no polymerization activity. If the ratio exceeds 1000, the catalytic activity is lowered, and the resulting polyethylene may contain excess aluminum.

Wherein L is an amide group, an alkyl group, a benzyl group, and the pen group is as cocatalysts _{B (C 6 F 5) 3} , (R 1 R 2 NH) + B - (C 6 F 5) 4, and (R ¹ R ^{2 R 3 C) + B -} (C 6 F 5) using a boron compound-based organic anion selected from the group consisting of _4, and this time may be added to the alkyl aluminum with an impurity remover that contains a monomer or solvent. Wherein R ¹ , R ² , R ³ are the same as or different from each other hydrogen or a hydrocarbon radical of 1 to 20 carbon atoms. The preferred amount of the boron organic compound ion system is in the range of molar concentration (B / Ti molar ratio) of the promoter to the main catalyst in the range of 0.5 to 10, and the preferred amount of the impurity remover is the ratio (Al / Ti molar ratio) to the main catalyst. It is the range of 0-500, More preferably, it is the range of 1-100. If the ratio of the cocatalyst is less than 0.5, the catalyst is not activated. If it exceeds 10, the catalytic activity is deteriorated. If the amount of the impurity remover is more than 500, the catalyst activation reaction of the boron organic compound is interrupted and the polymerization activity of the catalyst is prevented. Is lowered.

The two components of the catalysts are separately introduced into the reactor or the two components are premixed and introduced into the reactor. In the case where the catalyst and the cocatalyst are mixed in advance, mixing conditions such as temperature and concentration are not particularly limited.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited by the following examples.

Example 1

Preparation of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiNMe ₂

In a 500 ml spherical glass reactor substituted with nitrogen, Me ₄ CpLi (Cp is cyclopentadienyl, 10.0 g, 78 mmol) was diluted with 200 ml of THF, cooled to -78 ° C, and then Me ₂ SiCl ₂ 10.7 g (93.6 mmol) ) Was slowly added dropwise and reacted with stirring for 3 hours. After THF and unreacted Me ₂ SiCl ₂ in the reaction solution were removed in vacuo, LiCl precipitate was filtered off using normal hexane, and normal hexane was removed in vacuo to give Me ₂ Si (Me ₄ Cp) as a yellow liquid. Cl (15.6 g, 73.2 mmol) was obtained. In another 500 ml spherical reactor, 5.28 g (87.8 mmol) of NH ₂ NMe ₂ was diluted in 200 ml of THF, cooled to −78 ° C., and 55 ml (87.8 mmol, 1.6 M normal hexane dilution) of n-BuLi was slowly added dropwise thereto. THF was removed in vacuo and 200 ml of ethyl ether was added to form a white slurry. After cooling to −78 ° C., 15.6 g (73.2 mmol) of the synthesized Me ₂ Si (Me ₄ Cp) Cl was diluted in 120 ml of diethyl ether, cooled to −78 ° C., and slowly added dropwise to the white slurry. After slowly warming to room temperature, the mixture was stirred for 24 hours. LiCl precipitate was filtered using diethyl ether, and diethyl ether was removed in vacuo to give an orange viscous liquid. This viscous liquid was separated by vacuum fractional distillation at 110 ° C. to obtain 10.95 g (63%) of light green viscous liquid.

¹ H-NMR (CDCl ₃ , 25 ° C.) δ2.44 (s, 1H, Me ₄ Cp-H), 2.37 (s, 6H, NNMe ₂ ),

1.94 (s, 6H, Me ₄ Cp-Me), 1.78 (s, 6H, Me ₄ Cp-Me), -0.06 (s, 6H, Me ₂ Si).

2.37 g (10 mmol) of the synthesized Me ₂ Si (Me ₄ Cp) Cl and 2.24 g (10 mmol) of Ti (NMe ₂ ) ₄ were added to a 250 ml spherical reactor under a nitrogen atmosphere and heated at 130 ° C. for 1 hour. After cooling to room temperature, by-product Me ₂ NH was removed by vacuum for about 10 minutes, and again filled with argon, and then heated to 130 ° C. for 1 hour. This process was repeated four times, followed by recrystallization with normal pentane to obtain 2.0 g (53.7%) of the red solid compound of FIG. 1.

¹ H-NMR (CDCl ₃ , 25 ° C.) δ 2.99 (s, 12H, TiNMe ₂ ), 2.49 (s, 6H, NNMe ₂ ),

2.11 (s, 6H, Me ₄ Cp-Me), 2.02 (s, 6H, Me ₄ Cp-Me), 0.49 (s, 6H, Me ₂ Si).

¹³ C-NMR (CDCl ₃ , 25 ° C.) δ 127.6, 124.9, 103.1, 51.1, 48.6, 14.0, 11.7, 4.6.

Example 2

Preparation of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiCl ₂

Example 1 a Me ₂ Si (Me ₄ Cp) prepared in _{(NNMe 2) Ti (NMe 2} ) 2 and then to 1.0g (2.69mmol) dissolved in 60ml CH ₂ Cl ₂ solvent, CH ₂ Cl ₂ solvent at room temperature 20ml 0.72 g (6.8 mmol) of diluted SiMe ₃ Cl was slowly added dropwise and stirred for 5 hours. The solvent was removed in vacuo, washed with diethyl ether and filtered off under toluene to remove the solvent in vacuo. Again recrystallized with toluene to obtain 0.6g (63%) of the compound yellow needle-like crystal of FIG.

¹ H-NMR (CDCl ₃ , 25 ° C.) δ 2.95 (s, 6H, NNMe ₂ ), 2.20 (s, 6H, Me ₄ Cp-Me),

1.92 (s, 6H, Me ₄ Cp-Me), 0.66 (s, 6H, Me ₂ Si).

¹³ C-NMR (CDCl ₃ , 25 ° C.) δ 136.4, 133.1, 96.5, 50.0, 15.5, 12.2, 4.2.

Example 3

Method for preparing Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) (AlMe ₃ ) TiMe ₂

1.0 g (2.69 mmol) of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) Ti (NMe ₂ ) ₂ prepared in Example 1 was dissolved in 60 ml of toluene solvent and cooled to −50 ° C., followed by 20 ml of normal pentane solvent. 1.96 g (27.2 mmol) of diluted AlMe ₃ was slowly added dropwise at -50 占 폚. The mixture was stirred for 4 hours while gradually warming to room temperature. The solvent was removed in vacuo and filtered off with normal pentane. The normal pentane solvent was removed to some extent and recrystallized to obtain 0.9 g (43%) of the compound light green needle-like crystal of FIG. 3.

¹ H-NMR (CDCl ₃ , 25 ° C.) δ3.29 (s, 6H, NNMe ₂ ), 2.18 (s, 6H, Me ₄ Cp-Me),

1.98 (s, 6H, Me ₄ Cp-Me), 0.60 (s, 6H, Me ₂ Si), 0.40 (s, 6H, Ti-Me),

-0.84 (s, 9H, AlMe ₃ ).

¹³ C-NMR (CDCl ₃ , 25 ° C.) δ 135.7, 131.5, 101.1, 55.8, 15.2, 12.4, 6.01, -7.4.

Example 4

Method for preparing Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiMe ₂

1.0 g (2.6 mmol) of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) (AlMe ₃ ) TiMe ₂ prepared in Example 3 was dissolved in 30 ml of toluene solvent, cooled to −78 ° C., and diluted with 10 ml of toluene solvent. 0.28 g (2.7 mmol) of Et ₃ N was slowly added dropwise at -78 ° C. The mixture was stirred for 4 hours while gradually warming to room temperature. The solvent was removed in vacuo and filtered off with normal pentane. The normal pentane solvent was removed to some extent and recrystallized to obtain 0.63 g (77.4%) of the yellow crystal of the compound of FIG. 4.

¹ H-NMR (CDCl ₃ , 25 ° C.) δ3.00 (s, 6H, NNMe ₂ ), 2.17 (s, 6H, Me ₄ Cp-Me),

1.72 (s, 6H, Me ₄ Cp-Me), 0.43 (s, 6H, Me ₂ Si), -0.39 (s, 6H, Ti-Me).

¹³ C-NMR (CDCl ₃ , 25 ° C.) δ 129.4, 125.5, 91.4, 52.2, 41.2, 14.5, 11.7, 5.1.

Example 5

1.5 mL of normal hexane and 50 mL of 1-octene were added to a 2.5 L stainless steel reactor, and 10 mmol of MAO (MMAO-4, manufactured by Tosoh Akzo) as a promoter was added thereto. After the temperature of the reactor was heated to 140 ° C., 7.45 mg (20 μmol) of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiNMe ₂ , which was the catalyst prepared in Example 1, was added thereto, and the pressure in the reactor was increased to 30 with ethylene. Filled up to barometric pressure. Ethylene was continuously supplied at a pressure of 30 atm, followed by polymerization for 30 minutes, and then 10 ml of ethanol was added to terminate the polymerization. After the reactor was cooled, the product was recovered and dried in a vacuum oven at 60 ° C. for 8 hours, yielding 16.2 g of polymer. As a result of analysis by GPC of the polymer, the weight average molecular weight was 150,000 and the molecular weight distribution (Mw / Mn) was 33.0.

Example 6

The polymer obtained in the same manner as in Example 5, except that 7.1 mg (20 μmol) of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiCl ₂ prepared in Example 2 was added as a catalyst. The weight of 10.0 g was. Also, as a result of analysis by GPC, the weight average molecular weight of the polymer was 900,000 and the molecular weight distribution (Mw / Mn) was 41.6.

Example 7

The polymerization was carried out in the same manner as in Example 6 except that the polymerization temperature was 80 ° C and the pressure of ethylene was 8 atm, and the weight of the obtained polymer was 40.0 g. Moreover, as a result of analysis by GPC, the weight average molecular weight of the polymer was 2.2 million and the molecular weight distribution (Mw / Mn) was 140.

Example 8

The polymerization was carried out in the same manner as in Example 6 except that the polymerization temperature was 50 ° C and the pressure of ethylene was 8 atm, and the weight of the obtained polymer was 40.0 g. As a result of analysis by GPC, the weight average molecular weight of the polymer was 790,000 and the molecular weight distribution (Mw / Mn) was 27.

Example 9

The same procedure as in Example 5 was carried out except that 7.73 mg (20 μmol) of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) (AlMe ₃ ) TiMe ₂ prepared in Example 3 was added as a catalyst. The polymer thus obtained had a weight of 15.2 g. As a result of analysis by GPC, the weight average molecular weight of the polymer was 520,000 and the molecular weight distribution (Mw / Mn) was 23.7.

Example 10

1.5 mL of normal hexane and 50 mL of 1-octene were added to a 2.5 L stainless steel reactor, and 1.0 mL of triisobutylaluminum was added as an impurity remover. The reactor was heated to 140 ° C., and then 31.4 mg (100 μmol) of Me ₂ Si (Me ₄ Cp) (NNMe ₂ ) TiMe ₂ , a catalyst prepared in Example 4, and Ph ₃ C ⁺ B ⁻ ( 92.2 mg (100 μmol) of C ₆ F ₅ ) ₄ were added thereto, and the pressure in the reactor was filled with ethylene to 30 atm. Ethylene was continuously supplied at a pressure of 30 atm, followed by polymerization for 30 minutes, and then 10 ml of ethanol was added to terminate the polymerization. After the reactor had cooled down, the product was recovered and dried in a vacuum oven at 60 ° C. for 8 hours, yielding 50.0 g of polymer. Analysis of the polymer by GPC showed a weight average molecular weight of 1.3 million and a molecular weight distribution (Mw / Mn) of 29.2.

Example 11

Except that the polymerization temperature was 80 ℃ was carried out in the same manner as in Example 10, the weight of the polymer was 250g. As a result of analysis by GPC, the weight average molecular weight of the polymer was 260,000 and the molecular weight distribution (Mw / Mn) was 9.03.

The weight average molecular weight of the polymer obtained in the above embodiment is very high at 150,000 or more even at a polymerization temperature of 140 ° C. or more, and the molecular weight distribution is very wide at 10 or more. The high molecular weight polyethylene can be produced even at high temperature solution polymerization by the catalyst of the present invention, and despite being a homogeneous metallocene catalyst, a polyethylene polymer having a wide molecular weight distribution can be prepared. In the conventional case, the molecular weight distribution is very narrow as 2 to 4.

As described above, the catalyst according to the present invention has excellent thermal stability and is effective in a solution polymerization process carried out at a high temperature. In addition, the polyethylene prepared by using the catalyst can easily control physical properties such as molecular weight, molecular weight distribution and density. And high molecular weight.

Claims (8)

Metallocene catalyst for producing polyethylene, characterized in that the geometrically restricted metallocene catalyst represented by the formula (1) or (2). [Formula 1] [Formula 2] Here, M is one transition metal selected from the group consisting of Group 3, Group 4-10, and lanthanide-based metal of the periodic table, Cp is a cyclopentadienyl derivative capable of π-bond with M, D is is nitrogen or phosphorus element, LB is ^{oR *, SR *, PR *} 2, and NR ^* ₂ is a Lewis base electron donor substituents selected from the group consisting of, LA is a trialkyl aluminum, an aluminum alkyl di di alkylhalo halo-aluminum, di-alkyl magnesium, and one of the organic metal compound Lewis acid selected from the group consisting of magnesium to an alkyl, B is _{^{SiR * 2, CR * 2,}} SiR * 2 SiR * 2, CR * 2 CR * ₂ , CR ^* = CR ^* , CR ^* ₂ SiR ^* ₂ , GeR ^* ₂ , BR ^* ₂ , and BR ^* ₂ , one crosslinking group selected from the group consisting of L having a total number of atoms of 20 or less in addition to hydrogen Halogen group, alkyl group, allyl group, silyl group, amine group, amide group, allyl group, al One or two substituents selected from the group consisting of a cock group, a haloalkyl group, and a haloallyl group, R ^* is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, cyclohexyl, dicyclohexylmethyl, Phenyl, methylphenyl, and adamantyl. The metallocene catalyst for producing polyethylene according to claim 1, wherein M is one transition metal selected from the group consisting of titanium, zirconium, and hafnium. The method of claim 1, wherein Cp is cyclopentadienyl, methylcyclopentadienyl, dimethylcyclopentadienyl, tetramethylcyclopentadienyl, butylcyclopentadienyl, t-butylmethylcyclopentadienyl, trimethylsilyl Metallocene catalyst for producing polyethylene, characterized in that one cyclopentadienyl derivative selected from the group consisting of cyclopentadienyl, indenyl, methyl indenyl, and florenyl. The method of claim 1, wherein L is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, cyclohexyl, dicyclohexymethyl, phenyl, methylphenyl, benzyl , Chloride, dimethylamine group, diethylamide group, diphenylamide group, dibenzylamide group, dihexylamide group, methylethylamide group, methylphenylamide group, methylbenzylamide group, methylhexylami group, phenylbenzyl One selected from the group consisting of an amide group, a phenylhexylami group, a benzylhexylamide group, trimethylsilyl group, triethylsilyl group, methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, and isobutoxy group Or a metallocene catalyst for producing polyethylene, characterized in that two substituents. In polyethylene polymerization prepared by homopolymerization of ethylene or copolymerization of ethylene and α-olefin, as a main catalyst under a polymerization temperature of 0 to 300 ° C. and ethylene pressure of 1 to 1000 atm, the geometrically restricted metal represented by the following general formula (1) or (2) As the co-catalyst, one catalyst selected from the group consisting of methyl aluminoxane, alkyl haloaluminum and boron organic compound anions is used as a cocatalyst, and alkyl is removed to remove impurities contained in the monomer or solvent during polymerization. Aluminum is added in the range of 1-100 molar ratio with respect to a catalyst, The manufacturing method of the polyethylene characterized by the above-mentioned. [Formula 1] [Formula 2] Here, M is one transition metal selected from the group consisting of Group 3, Group 4-10, and lanthanide-based metal of the periodic table, Cp is a cyclopentadienyl derivative capable of π-bond with M, D is is nitrogen or phosphorus element, LB is ^{oR *, SR *, PR *} 2, and NR ^* ₂ is a Lewis base electron donor substituents selected from the group consisting of, LA is a trialkyl aluminum, an aluminum alkyl di di alkylhalo halo-aluminum, di-alkyl magnesium, and one of the organic metal compound Lewis acid selected from the group consisting of magnesium to an alkyl, B is _{^{SiR * 2, CR * 2,}} SiR * 2 SiR * 2, CR * 2 CR * ₂ , CR ^* = CR ^* , CR ^* ₂ SiR ^* ₂ , GeR ^* ₂ , BR ^* ₂ , and BR ^* ₂ , one crosslinking group selected from the group consisting of L having a total number of atoms of 20 or less in addition to hydrogen Halogen group, alkyl group, allyl group, silyl group, amine group, amide group, allyl group, al One or two substituents selected from the group consisting of a cock group, a haloalkyl group, and a haloallyl group, R ^* is methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, cyclohexyl, dicyclohexylmethyl, Phenyl, methylphenyl, and adamantyl. 6. The method of claim 5, wherein when L is one selected from the group consisting of halogen, amide, and alkyl groups, methylaluminoxane is used as a promoter, and the molar concentration ratio of the main catalyst to the promoter is in the range of 100 to 1000. Method for producing a polyethylene, characterized in that. 6. The alkyl halo of claim 5, wherein when L is an amide group or an alkoxy group, one alkyl halo selected from the group consisting of trimethylaluminum, triethylaluminum, diethylchloroaluminum, tributylaluminum, and triisobutylaluminum as a promoter Using aluminum, wherein the molar concentration ratio of the main catalyst to the promoter is in the range of 5 to 500. The method of claim 5, wherein when L is an amide group, an alkyl group, selected from a benzyl group and a phenyl group, B as the co-catalyst _{(C 6 F 5) 3,} (R 1 R 2 NH) + B - (C 6 F 5) _4, and ^{(R 1 R 2 R 3 C} ) + B - (C 6 F 5) , and use a single organic boron compound-based anion selected from the group consisting of _4, the molar concentration ratio of the main catalyst to cocatalyst is 0.5 to Method of producing a polyethylene, characterized in that the range of 10.