KR101265418B1 - A preparation method of catalyst for ethylene (co)polymerization - Google Patents

Abstract

The method for preparing a catalyst for ethylene polymerization and copolymerization according to the present invention comprises the steps of dissolving a magnesium halide compound in a mixed solvent of a cyclic ether and at least one alcohol to prepare a magnesium compound solution; (2) preparing a carrier by reacting the titanium compound with the magnesium compound solution; (3) reacting the carrier with an organoboron compound; (4) characterized in that it comprises the step of supporting the titanium by reacting the obtained carrier with a titanium compound.

The catalyst prepared by the catalyst production method of the present invention has a controlled particle shape, can easily control the particle size, and can be used to prepare a polymer having a high apparent density and a wide molecular weight distribution.

Ethylene Polymerization, Cyclic Ether, Alcohol, Metal Halide Compound, Trialkyl Borane, Solid Titanium Catalyst, Molecular Weight Distribution

Description

Process for producing catalyst for ethylene polymerization and copolymerization {A PREPARATION METHOD OF CATALYST FOR ETHYLENE (CO) POLYMERIZATION}

The present invention relates to a method for preparing a catalyst for ethylene polymerization and copolymerization, and more particularly, dissolving a magnesium halide compound in a mixed solvent of a cyclic ether and at least one alcohol to prepare a magnesium compound solution; (2) preparing a carrier by reacting the titanium compound with the magnesium compound solution; (3) reacting the carrier with an organoboron compound; (4) a method for producing a catalyst for ethylene polymerization and copolymerization comprising reacting the obtained carrier with a titanium compound to support titanium.

Catalysts for ethylene polymerization and copolymerization containing magnesium are known to provide polymers with very high catalytic activity and high apparent density, and are also suitable for liquid and gas phase polymerization. Ethylene liquid polymerization refers to a polymerization process performed in medium such as bulk ethylene, isopentane and hexane, and in the catalyst used therein, high activity, catalyst shape, size, size distribution, apparent density, and soluble in medium Low molecular weight content is an important characteristic of catalysts when considering process applicability.

Many olefin polymerization catalysts and catalyst preparation processes are reported in the art, including magnesium and based on titanium. In particular, many methods using magnesium solution are known to obtain the above-mentioned apparent density olefin polymerization catalyst. There is a method of obtaining a magnesium solution by reacting a magnesium compound with an electron donor such as an alcohol, an amine, a cyclic ether, an organic carboxylic acid in the presence of a hydrocarbon solvent, and US Pat. Mention is made of the use of alcohols. In addition, a method of preparing a magnesium supported catalyst by reacting the liquid magnesium solution with a halogen compound such as titanium tetrachloride is well known. Such catalysts provide a high apparent density, but there is a need to be improved in terms of the active or hydrogen reactivity of the catalyst. Tetrahydrofuran, a cyclic ether, is used in US Pat. Nos. 4,477,639 and 4,518,706 as solvents of magnesium compounds.

U.S. Patent Nos. 4,847,227, 4,816,433, 4,829,037, 4,970,186, and 5,130,284 have excellent polymerization activity by reacting electron donors such as magnesium alkoxides, dialkylphthalates, phthaloyl chlorides, and titanium chloride compounds. In addition, there has been reported an invention for producing a catalyst for olefin polymerization capable of providing a polymer having an improved apparent density.

U.S. Patent Nos. 4,347,158, 4,422,957, 4,425,257, 4,618,661 and 4,680,381 propose methods for preparing a catalyst after pulverizing Lewis acid compounds such as aluminum chloride to magnesium chloride as a support. However, although the catalytic activity is complemented in the above patents, there are disadvantages in that the shape of the catalyst is irregular in terms of the shape of the catalyst, such as the size, size distribution, and stereoregularity.

U.S. Patent No. 5,459,116 reports a method of preparing a supported titanium solid catalyst by bringing a magnesium compound solution and a titanium compound into contact with each other containing an ester having at least one hydroxyl group as an electron donor. However, this method can provide a catalyst that provides a polymer having excellent polymerization activity and apparent density, but there is room for improvement in terms of particle shape.

As described above, while the manufacturing process is simple, it is required to develop a new catalyst for ethylene polymerization and copolymerization, which can give high polymer apparent density by controlling high polymerization activity and shape and size of catalyst particles.

An object of the present invention is to solve the problems of the prior art as described above, by controlling the catalytic activity and particle size, ethylene polymerization and copolymerization capable of producing an ethylene (co) polymer having a high apparent density and a wide molecular weight distribution It is to provide a catalyst production method that can be efficiently prepared for the catalyst for a simple process.

The process for preparing the catalyst for ethylene polymerization and copolymerization of the present invention is characterized by comprising the following steps:

(1) dissolving a magnesium halide compound in a mixed solvent of a cyclic ether and at least one alcohol to prepare a magnesium compound solution;

(2) preparing a carrier by reacting the magnesium compound solution with a titanium compound represented by the following general formula (I);

Ti (OR) _a X _(4-a) ‥‥‥ (I)

[Where R is an alkyl group of 1 to 10 carbon atoms, X is a halogen atom and a is an integer of 0 to 4]

(3) reacting the carrier with an organoboron compound represented by the following general formula (II);

R _a BX _b ‥‥‥ (II)

[Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom such as chlorine, bromine, iodine, fluorine, a and b are integers of 0 to 3, a + b = 3]

(4) reacting the obtained carrier with a titanium compound to support titanium.

In the step (1) of preparing the magnesium compound solution, as the magnesium halide compound, dihalogenated magnesium such as magnesium chloride, magnesium iodide, magnesium fluoride and magnesium bromide; Alkylmagnesium halides such as methylmagnesium halide, ethylmagnesium halide, propylmagnesium halide, butylmagnesium halide, isobutylmagnesium halide, hexylmagnesium halide, amylmagnesium halide and the like; Alkoxymagnesium halides such as methoxymagnesium halide, ethoxymagnesium halide, isopropoxymagnesium halide, butoxymagnesium halide and octoxymagnesium halide; One or two or more mixtures selected from the group exemplified by aryloxymagnesium halides, such as phenoxymagnesium halides and methylphenoxymagnesium halides, or complexed forms with other metals can be used.

The compounds listed above may be represented by simple chemical formulas, but in some cases, they may not be represented by simple formulas depending on the method of preparing magnesium compounds. In this case, it can be regarded as a mixture of magnesium compounds listed generally. For example, a compound obtained by reacting a magnesium compound with a polysiloxane compound, a halogen-containing silane compound, an ester, an alcohol, or the like; Compounds obtained by reacting magnesium metal with alcohol, phenol, or ether in the presence of halo silane or thionyl chloride can also be used in the present invention. Preferred magnesium compounds are magnesium halides, in particular magnesium chloride, alkyl magnesium chlorides, preferably having C ₁ to C ₁₀ alkyl groups, alkoxy magnesium chlorides, preferably having C ₁ to C ₁₀ alkoxy, and aryloxy magnesium It is preferred to have chlorides, preferably C ₆ -C ₂₀ aryloxy.

In the step (1) of preparing the magnesium compound solution, it is preferable to use a mixed solvent of a cyclic ether and at least one alcohol when converting the magnesium halide compound into a magnesium compound solution. The cyclic ether to be used is a cyclic ether having 3 to 6 carbons in the ring and derivatives thereof, particularly preferably tetrahydrofuran, 2-methyltetrahydrofuran and the like, and most preferably tetrahydrofuran. The alcohol to be used includes monohydric or polyhydric alcohols having 1 to 20 carbon atoms, preferably alcohols containing 2 to 12 carbon atoms. There is no particular limitation on the mixing ratio of the cyclic ether and at least one alcohol.

The amount of the mixed solvent of the cyclic ether and the at least one alcohol in the preparation of the magnesium compound solution is preferably 1 to 20 mol, more preferably about 2 to 10 mol per mol of the magnesium halide compound. If the amount used is less than 1 mole, dissolution of the magnesium compound is not preferable. If the amount is more than 20 mole, the amount of the titanium compound to be added to obtain the catalyst particles during the catalyst preparation process becomes too large, making it difficult to control the particles. Not desirable

In step (1) of preparing the magnesium compound solution, the magnesium compound solution may be prepared by contacting a magnesium halide compound with a mixed solvent of a cyclic ether and at least one alcohol in the presence or absence of a hydrocarbon solvent. have. Hydrocarbon solvents used herein include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane and kerosene; Alicyclic hydrocarbons such as cyclobenzene, methylcyclobenzene, cyclohexane and methylcyclohexane; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, cumene and cymene; Or halogenated hydrocarbons such as dichloropropane, dichloroethylene, trichloroethylene, carbon tetrachloride and chlorobenzene can be used.

In the step (1) of preparing the magnesium compound solution, the dissolution temperature at the time of preparation of the magnesium compound solution varies depending on the type and amount of the cyclic ether and the alcohol, but is from room temperature to 200 ° C, preferably about 50 ° C to 150 ° C. It is preferable to dissolve at a temperature of.

In the step (2) of preparing the carrier, a solid particle used as the carrier is obtained by reacting the resultant magnesium compound solution with the titanium compound represented by the following general formula (I):

Ti (OR) _a X _(4-a) ‥‥‥ (I)

[Where R is an alkyl group having 1 to 10 carbon atoms, X is a halogen atom and a is an integer of 0 to 4].

Examples of the titanium compound that satisfies the general formula (I) include titanium tetrahalides such as TiCl ₄ , TiBr ₄ and TiI ₄ ; Trihalogenated alkoxytitanium such as Ti (OCH ₃ ) Cl ₃ , Ti (OC ₂ H ₅ ) Cl ₃ , Ti (OC ₂ H ₅ ) Br ₃ and Ti (O (iC ₄ H ₉ )) Br ₃ ; Dihalogenated alkoxytitanium such as Ti (OCH ₃ ) ₂ Cl ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ , Ti (O (iC ₄ H ₉ )) ₂ Cl ₂ and Ti (OC ₂ H ₅ ) ₂ Br ₂ ; Tetraalkoxytitanium such as Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ and Ti (OC ₄ H ₉ ) ₄ ; Or a mixture thereof. The preferred titanium compound is a halogen-containing titanium compound, and the more preferred titanium compound is titanium tetrachloride.

The amount of the titanium compound used in the step (2) of preparing the carrier is preferably 0.1 to 500 mol, more preferably 0.1 to 300 mol, and most preferably 0.2 to 200 mol per mol of the magnesium halide compound. When the magnesium compound solution and the titanium compound are reacted, the shape and size of the solid component recrystallized by the reaction conditions vary greatly. Therefore, it is preferable that reaction of a magnesium compound solution and a titanium compound is performed at a suitable temperature, and produces | generates a solid component. It is preferable to perform a contact reaction at 10 to 70 degreeC, and it is more preferable to carry out at 20 to 50 degreeC. After the contact reaction, the reaction temperature is gradually raised, and then sufficiently reacted at 50 ° C. to 150 ° C. for 0.5 hours to 5 hours for aging.

In step (3), the carrier obtained in step (2) is reacted with an organoboron compound represented by the following general formula (II):

R _a BX _b ‥‥‥ (II)

[Where R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom such as chlorine, bromine, iodine or fluorine, a and b are integers of 0 to 3, a + b = 3].

Examples of the organic boron compound that satisfies the general formula (II) include triethyl borane, tributyl borane, triethyl borate, triisopropylborate, tributyl borate, chlorodiethyl boron, bromodiethyl boron, dichloroethyl boron, Dibromoethyl boron, chlorodibutyl boron, bromobutyl boron, dichlorobutyl boron, dibromobutyl boron, trichloroboron, tribromoboron and the like.

The amount of the organoboron compound to be reacted with the carrier is preferably 0.01 to 30 mol, more preferably 0.05 to 20 mol per mol of the magnesium halide compound. If the amount of the organoboron compound is less than 0.01 mole, the activity of the catalyst is drastically decreased, and if the amount of the organoboron compound is more than 30 moles, the shape of the catalyst is destroyed, which is not preferable.

In addition, when the carrier and the organic boron compound are reacted, the form of the catalyst is greatly changed depending on the reaction temperature, so it is preferable to carry out at a sufficiently low temperature. It is preferable to perform reaction at the temperature of -50 degreeC-80 degreeC, and it is more preferable to carry out at -20 degreeC-50 degreeC. After the contact reaction, the reaction temperature was gradually raised and reacted at 40 ° C. to 150 ° C. for 0.5 hours to 5 hours.

In the step (4), the carrier obtained in the step (3) is further reacted with a titanium compound to support titanium, wherein as the titanium compound, Ti (OR) _a X _4-a (R) of the general formula (I) Silver hydrocarbon group, X is a halogen atom, a is an integer of 0-4), The titanium compound can be used, It is most preferable to use titanium tetrachloride among the examples of a titanium compound.

The amount of the titanium compound used in the step (4) of supporting titanium is preferably 0.5 to 30 moles, more preferably 1 to 20 moles per mol of the magnesium halide compound, and the reaction is performed at 40 ° C. to 150 ° C. for 0.5 to 5 hours. It is desirable to. If the amount of the titanium compound used in the step (4) is less than 0.5 mole is not activated because it is not good, if it exceeds 30 moles may affect the shape of the carrier is not preferred, the reaction temperature or If the time is outside the above range may affect the shape of the carrier is not preferred.

In the step (4), the reaction of the titanium compound may be completed in one reaction, or may be completed in two or three or more reactions, but it is determined in consideration of the performance of the catalyst, the material input, and the economics of the reaction. good.

After completion of the reaction in the step (4), the solid catalyst is separated and washed with an organic solvent such as hexane and dried to obtain the final catalyst.

The catalyst produced by the process according to the invention is advantageously used for the polymerization and copolymerization of ethylene. In particular, the catalyst can be used for homopolymerization of ethylene and copolymerization of ethylene with 3 or more carbon atoms α-olefins such as propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene.

The polymerization reaction in the presence of the catalyst produced by the process of the invention comprises (i) a solid complex titanium catalyst prepared by the process according to the invention consisting of magnesium, titanium, halogen and boron compounds, and (ii) Periodic Table II. It can be carried out using a catalyst system comprising a group or group IIIA organometallic compound.

The solid complex titanium catalyst (i) prepared by the process of the present invention may be prepolymerized with ethylene or α-olefin before being used as a component in the polymerization reaction. Prepolymerization helps to improve the shape of the polymer after polymerization by surrounding the catalyst particles with a polymer to maintain the catalyst shape. Prepolymerization can be carried out in the presence of a hydrocarbon solvent such as hexane, at sufficiently low temperatures and under ethylene or α-olefin pressure conditions, in the presence of the catalyst component and an organoaluminum compound such as triethylaluminum. The weight ratio of polymer to catalyst after prepolymerization is usually from 0.1: 1 to 60: 1.

Examples of the organometallic compound of (ii) include a compound represented by MR _n , wherein M is a periodic table group II or IIIA metal component such as magnesium, calcium, zinc, boron, aluminum and gallium, and R is C1-C20 alkyl groups, such as methyl, ethyl, butyl, hexyl, octyl and decyl, n represents the valence of a metal component. Preferred examples of the organometallic compound include trialkylaluminum having 1 to 6 carbon atoms, such as triethylaluminum and triisobutylaluminum, and mixtures thereof. In some cases, organoaluminum compounds having one or more halogen or hydride groups such as ethylaluminum dichloride, diethylaluminum chloride, ethylaluminum sesquichloride or diisobutylaluminum hydride may be used.

The polymerization reaction in the presence of the catalyst produced by the process of the present invention can be carried out by gas phase or bulk polymerization in the absence of an organic solvent, or by liquid phase slurry polymerization in the presence of an organic solvent. These polymerization methods can be carried out in the absence of oxygen, water and other compounds that can act as catalyst poisons. In the case of liquid phase slurry polymerization, the preferred concentration of the solid complex titanium catalyst (i) on the polymerization reaction system is about 0.001 to 5 millimoles, preferably about 0.001 to 0.5 millimoles of titanium atoms of the catalyst per liter of solvent. Solvents include alkanes such as pentane, hexane, heptane, n-octane and isooctane; Cycloalkanes such as cyclohexane and methylcyclohexane; Alkylaromatics such as toluene, xylene, ethylbenzene, isopropylbenzene, ethyltoluene, n-propylbenzene and diethylbenzene; Halogenated aromatics such as chlorobenzene, chloronaphthalene, ortho-dichlorobenzene; And mixtures thereof. In the case of gas phase polymerization, the preferred amount of the solid complex titanium catalyst (i) is about 0.001 to 5 mmol, preferably about 0.001 to 1.0 mmol, most preferably about 0.01 titanium atom of the catalyst per liter of the polymerization zone. ˜0.5 mmol. In the polymerization reaction, the preferred concentration of the organometallic compound (ii) is about 1 to 2000 moles per mole of titanium atoms in the solid complex titanium catalyst (i), more preferably about 5 to 500 moles, calculated in terms of metal atoms. .

In order to obtain a high polymerization rate, the polymerization reaction is preferably carried out at a sufficiently high temperature irrespective of the type of polymerization process, and is generally polymerized at about 20 to 200 ° C, more preferably at 20 to 95 ° C. At the time of the said superposition | polymerization, atmospheric pressure-100 atmospheres are preferable, and, as for the pressure of a monomer, 2-50 atmospheres are more preferable.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, these embodiments are for illustrative purposes only, and the present invention is not limited to these embodiments.

When the polymerization is carried out using the catalyst prepared by the method for preparing a catalyst of the present invention, a high activity catalyst can be prepared with a high catalyst yield, and the catalyst can be used as an ethylene homopolymer having a high apparent density and a wide molecular weight distribution. Copolymers of ethylene and α-olefins can be obtained in high yields.

Examples and Comparative Examples

The particle size distribution of the catalyst was measured using a laser particle analyzer (Mastersizer X, Malvern Instruments), and the results were expressed as average size D (v, 0.5), where D (v, 0.5) was 50% of the sample. The particle size indicated is shown and the composition of the catalyst was analyzed by ICP.

Example 1

[Preparation of solid catalyst for ethylene polymerization and copolymerization]

(1) step: preparing a magnesium compound solution

230 g of MgCl ₂ , 2800 mL of toluene, 220 mL of tetrahydrofuran, and 730 mL of butanol were added to a 10 L reactor equipped with a mechanical stirrer, which was replaced with a nitrogen atmosphere. .

(2) step: preparing a solid carrier

The temperature of the solution obtained in the above step (1) was cooled to 35 ° C., 415 mL of TiCl _{4 was} charged over 80 minutes, the temperature of the reactor was raised to 60 ° C. over 1 hour, and aged for 1 hour. The reaction was allowed to stand for 30 minutes after the reaction to settle the carrier, and the upper solution was removed. 3000 mL of hexane was added to the slurry remaining in the reactor, and the mixture was washed three times by stirring, standing, and removing the supernatant.

(3) step: reaction step with organoboron compound

Into the slurry obtained in the step (2) was injected 750 ml of a 1 molar solution of triethylboron at a temperature of 0 ° C. After completion of the injection, the reactor temperature was raised to 50 ° C. and maintained at this temperature for 2 hours. After 2 hours, the reactor was cooled to room temperature, 400 ml of heptane was injected and washed, and then dried in a nitrogen atmosphere.

(4) step: preparing the catalyst

The carrier prepared in step (3) was added to 1600 mL of toluene at 5 ° C., 1400 mL of TiCl ₄ was added at a stirring speed of 250 rpm, and the temperature of the reactor was raised to 70 ° C. for 1 hour, and aged for 2 hours. After allowing to stand for 30 minutes, the precipitate was settled and the supernatant was separated. The prepared catalyst slurry was washed 7 times with 1600 mL of purified hexane.

The catalyst thus prepared had an average particle size of 6.4 μm and a titanium (Ti) content of 6.2 wt%.

[polymerization]

The high-pressure reactor with a capacity of 2 liters was dried in an oven and then assembled in a hot state, and then nitrogen and vacuum were operated three times in alternation to make the reactor into a nitrogen atmosphere. After 1000 mL of n-hexane was injected into the reactor, 2 mmol of triethylaluminum and 1000 mL of hydrogen were injected. The temperature of the reactor was raised to 80 ° C. while stirring at 700 rpm with a stirrer, and the ethylene pressure was adjusted to 120 psig. Then, 0.03 mmol of the solid catalyst prepared above was injected into the titanium atom, and polymerization was performed for 1 hour. After completion of the polymerization, the temperature of the reactor was lowered to room temperature, and excess ethanol solution was added to the polymerization contents. The resulting polymer was collected separately and dried in a vacuum oven at 50 ° C. for at least 6 hours to obtain a white powder of polyethylene.

Polymerization activity (kg polyethylene / g catalyst) was calculated as the weight (kg) ratio of the resulting polymer per gram of catalyst used. The prepared polyethylene powder was subjected to molecular weight distribution (Mw / Mn) analysis using GPC, which is a common method in the art. The polymerization results are shown in Table 1 together with the apparent density (g / ml) of the polymer.

Example 2

In the step (3) of Example 1, except that 1200 ml of 1 mol solution of triethylboron was injected, the same process as in Example 1 was carried out, and polymerization was carried out in the same manner. The results of Example 2 are shown in Table 1. The titanium content of the prepared catalyst was 7.9 wt%.

Example 3

In the step (3) of Example 1, except that 750 ml of 1 mol solution of tributylboron was injected, the same process as in Example 1 was carried out, and polymerization was carried out in the same manner. The results of Example 3 are shown in Table 1. The titanium content of the prepared catalyst was 6.3 wt%.

Example 4

In the step (3) of Example 1, except that 750 ml of 1 mol solution of triethylborate was injected, the same process as in Example 1 was carried out, and polymerization was carried out in the same manner. The results of Example 4 are shown in Table 1. The titanium content of the prepared catalyst was 7.5% by weight.

Comparative Example 1

In Step (3) of Example 1, except that triethyl boron was not reacted, the same process as in Example 1 was carried out, and polymerization was carried out in the same manner. The results of Comparative Example 1 are shown in Table 1.

Comparative Example 2

In step (1) of Example 1, tetrahydrofuran was used, and the same procedure as in Example 1 was carried out except that butanol was not used, and polymerization was carried out in the same manner. The results of Comparative Example 2 are shown in Table 1.

Comparative Example 3

(Stage 1

95 g of MgCl ₂ and 4000 mL of toluene were added to a 1.0 L reactor equipped with a mechanical stirrer, which was replaced with a nitrogen atmosphere, stirred at 300 rpm, and then 620 mL of 2-ethylhexanol was added thereto. The homogeneous solution obtained by reacting for a time was cooled to 70 ° C.

(2) Step

The magnesium compound solution obtained in step (1) was cooled to 70 ° C., and then 100.0 mL of silicon tetraethoxide was added to react for 1 hour.

(3) Step

The solution was adjusted to room temperature (25 ° C.) and 600 mL of titanium tetrachloride was added dropwise for 1 hour. When the dropwise addition was completed, the temperature of the reactor was raised to 70 ° C. over 1 hour, and maintained for 1 hour. After stopping the stirring, the solution of the upper layer was separated, and then 300 ml of a 1 mole solution of ethyl aluminum dichloride was injected into the prepared slurry at a temperature of 0 ° C. After completion, the reactor temperature was raised to 50 ° C. and maintained at this temperature for 2 hours. After 2 hours, the reactor was cooled to room temperature, 400 ml of heptane was injected and washed, and then dried in a nitrogen atmosphere. 3000 ml of toluene and 1000 ml of titanium tetrachloride were continuously injected into the obtained solid carrier, and the temperature was raised to 100 ° C. and maintained for 2 hours. After the reaction, the reactor was cooled to room temperature, and washed with 4000 ml of hexane until unreacted free titanium tetrachloride was removed. The titanium content of the prepared solid catalyst was 4.9 wt%. The polymerization was carried out in the same manner as in Example 1 using the obtained catalyst. The results of Comparative Example 3 are shown in Table 1.

Comparative Example 4

In step (2) of Comparative Example 3, except that the reaction was carried out for 1 hour without using silicon tetraethoxide, was prepared in the same manner as in Comparative Example 3, and the polymerization was carried out in the same manner. The results of Comparative Example 4 are shown in Table 1.

Polymerization activity
(kgPE / g catalyst) Apparent density
(g / ml) Molecular Weight Distribution (Mw / Mn) Example 1 22.2 0.37 8.4 Example 2 20.9 0.36 9.2 Example 3 23.7 0.35 8.7 Example 4 19.2 0.36 9.2 Comparative Example 1 14.4 0.28 6.9 Comparative Example 2 12.9 0.25 6.4 Comparative Example 3 14.3 0.29 6.3 Comparative Example 4 15.8 0.23 6.8

Claims (5)

A process for preparing a catalyst for ethylene polymerization or copolymerization comprising the following steps: (1) dissolving a magnesium halide compound in a mixed solvent of a cyclic ether and at least one alcohol to prepare a magnesium compound solution; (2) preparing a carrier by reacting the magnesium compound with the titanium compound solution; (3) 반응 step of reacting the carrier obtained in step (2) with an organoboron compound: and (4) reacting the carrier obtained in step (3) with a titanium compound to support titanium. The catalyst for ethylene polymerization or copolymerization according to claim 1, wherein the cyclic ether of step (1) is tetrahydrofuran or 2-methyl tetrahydrofuran, and the alcohol is a monovalent or polyhydric alcohol having 1 to 20 carbon atoms. Manufacturing method. The method of claim 1, wherein the titanium compound of step (2) and step (4) is represented by the following general formula (I): Ti (OR) _a X _(4-a) ‥‥‥ (I) [Where R is an alkyl group of 1 to 10 carbon atoms, X is a halogen atom and a is an integer of 0 to 4]. The method of claim 1, wherein the organoboron compound of step (3) is represented by the following general formula (II): R _a BX _b ‥‥‥ (II) [Wherein R is hydrogen or an alkyl, alkoxy, haloalkyl or aryl group having 1 to 10 carbon atoms, X is a halogen atom, a and b are integers of 0 to 3, a + b = 3]. The method of claim 4, wherein the organic boron compound is triethyl boron, tributyl boron, triethyl borate, triisopropyl borate or tributyl borate.