KR0143967B1 - Process for preparing catalyst composition for polymerizing polyolefins - Google Patents

Abstract

The present invention provides a method for producing a Ziegler-Natta catalyst composition for use in the polymerization of ethylene and an α-olefin having 3 to 8 carbon atoms, and a method for polymerizing an α-olefin having a specific particle size using the same.

According to the present invention, (1) mixing 1-200 moles of inert hydrocarbon solvent per mole of titanium to obtain a low concentration liquid titanium compound (A); (2) 0.01-3 per magnesium mole of magnesium compound in an inert hydrocarbon solvent Treatment with molar organic carboxylic acid ester to obtain organic carboxylic acid ester-containing magnesium compound (B): and titanium compound (A) obtained in step (1) and magnesium compound obtained in step (2) The catalyst composition is prepared by a process comprising contacting (B) in an amount of at least 0.1 mol of magnesium compound (B) per mol of titanium compound (A).

The catalyst composition prepared by the above method can be used to prepare a polymer having an average particle diameter controlled by polymerizing ethylene and an α-olefin having 3 to 8 carbon atoms.

Description

Process for preparing catalyst composition for particle size control of polyolefin polymer

The present invention relates to a method for preparing a Ziegler-Natta based catalyst composition and a method for polymerization using the same, and more particularly, to a method for preparing a titanium-magnesium based catalyst composition used to prepare a polyolefin polymer, and a polyolefin alone or using the same. It relates to a method for producing a copolymer.

Research to narrow the particle size distribution of polyolefin polymers has been quite effective. For example, Korean Patent Publication No. 86-1808 proposes a catalyst which has good fluidity, high bulk density, and precise particle size distribution of particles of suitable size, and Korean Patent Publication No. 83-1192 proposes a transition metal catalyst component on a carrier. A catalyst for producing polyolefins is proposed, which reduces cost and narrows the molecular weight distribution of the polymer by omitting the process of supporting it. In addition, Korean Patent Publication No. 84-256 proposes a method for preparing a catalyst for producing a granular spherical polymer having good fluidity while maintaining stereospecificity. In Japanese Patent Laid-Open No. 63-54004, a molecular weight regulator such as hydrogen is used during polymerization. Therefore, the olefin polymerization method which can prevent the change of the stereoregularity of a polymer even if the melt index of a polymer is changed is proposed.

These publications disclose that magnesium compounds, especially anhydrous magnesium chloride, are dissolved in a hydrocarbon solvent with a higher alcohol, especially 2-ethylhexanol, and then treated with an ester-based electron donor, and the liquid anhydrous magnesium chloride compound thus obtained is kept at a low temperature. The catalyst is prepared by recrystallization by treating with excess liquid titanium compound.

On the other hand, general titanium compounds used in the preparation of olefin polymerization catalysts are highly acidic and have strong corrosive properties, especially those which react violently with moisture and oxygen in the air. It is quite dangerous and can cause various problems or pollution problems in the process.

Under these circumstances, the present inventors have found that the catalyst can be used for the polymerization of ethylene and 3 to 8 α-olefins of carbohydrates, wherein the polymerized polymer is a spherical polymer with good fluidity and a narrow particle size distribution, As a result of intensive studies to provide a catalyst for preparing an unused polyolefin polymer, the present invention can be achieved by contacting a magnesium compound containing a low concentration liquid titanium compound with an organic carboxylic acid ester. It was completed.

That is, an object of the present invention is to provide a magnesium compound (B) in which a low concentration liquid titanium compound (A) in which a titanium compound is diluted in an amount of 5-40% by volume in an inert hydrocarbon solvent is reacted with at least one electron donor. In the composition, magnesium is 10-30% by weight, titanium is 1-10% by weight, the molar ratio of titanium atom to magnesium atom is 0.15-0.3, organic carboxylic acid ester is 5-30% by weight, specific surface area is 100- 1000 m ² / g, the average particle diameter is to provide a catalyst composition characterized in that 1 ~ 15μm.

Another object of the present invention is to obtain a low concentration liquid titanium compound (A) by mixing 1-200 mol of hydrocarbon per mol of titanium (1); (2) treating the magnesium compound with 0.01-1 mole of organic carboxylic acid ester per mole of the magnesium compound to obtain an organic carboxylic acid ester-containing magnesium compound (B); And (3) contacting the titanium compound (A) obtained in the step (1) and the magnesium compound (B) obtained in the step (2) in an amount of 0.1 mole or more of the magnesium compound (B) per mole of the titanium compound (A). It provides a method for producing a catalyst composition for producing a polyolefin polymer, characterized in that it comprises a.

Still another object of the present invention is to prepare ethylene and an α-olefin polymer having 3 to 8 carbon atoms, characterized in that the particle size of the polymer is controlled using the catalyst composition obtained by the above method. To provide a way.

Hereinafter, the present invention will be described in more detail.

The catalyst composition provided by the present invention (hereinafter referred to as a catalyst) is a titanium compound supported on a magnesium compound comprising at least one organic carboxylic acid ester. The catalyst is a liquid titanium compound having a low titanium concentration (A ) And a magnesium compound (B) containing an organic carboxylic acid ester as an electron donor.

The liquid titanium compound (A) having a low concentration can be obtained by mixing the titanium compound with a suitable hydrocarbon solvent [Step (1)]. The supported state of the catalyst can be controlled by controlling the concentration of the titanium compound in the hydrocarbon solvent. The particle size of the polyolefin polymer can be controlled by changing the concentration. The concentration range used in the present invention preferably includes 1 to 200 moles of hydrocarbon solvent per mole of titanium atoms in the titanium compound, preferably a mixing ratio of the titanium compound and the hydrocarbon solvent. Is in the range of 3 to 50 moles.

Examples of titanium compounds that can be used to form compound (A) include titanium tetrahalides such as TiCl ₄ , TiBr ₄ , and TiI ₄ , Ti (OCH ₃ ) Cl ₃ , Ti (On-C ₄ H ₉ ) Cl ₃ and Dihalogenated alkoxytitanium titanium such as TI (OC ₂ H ₅ ) Br ₃ , Ti (OCH ₃ ) ₂ CL ₂ , Ti (OC ₂ H ₅ ) ₂ Cl ₂ and Ti (OC ₂ H ₅ ) ₂ Br ₂ Halogenated trialkoxy titanium such as dialkoxy titanium, Ti (OCH ₃ ) ₃ Cl, Ti (OC ₂ H ₅ ) ₃ Cl, Ti (On-C ₄ H ₉ ) ₃ Cl and Ti (OC ₂ H ₅ ) ₃ Br And tetraalkoxy titanium, such as Ti (OCH ₃ ) ₄ , Ti (OC ₂ H ₅ ) ₄ and Ti (On-C ₄ H ₉ ) _4. Among these, titanium tetrahalide is particularly preferable.

Hydrocarbon solvents used as mixing agents to control the concentration of titanium compounds should be inert solvents that are not reactive with titanium compounds. Examples of such hydrocarbon solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane and kerosene. Alicyclic hydrocarbons such as cyclopentane, methyl cyclopentane, cyclohexane, methyl cyclohexane and cyclooctane; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene cumene and cymene.

Magnesium compound (B) comprising an organic carboxylic acid ester as an electron donor can be obtained by reacting a magnesium compound with an organic carboxylic acid ester in a suitable hydrocarbon solvent [Step (2)] to obtain a catalyst having a uniform particle size. In order to dissolve the magnesium compound using a suitable solubilizer, a method of treating the organic carboxylic acid ester may be employed.

Examples of magnesium compounds that can be used at this time include magnesium halides such as magnesium chloride, magnesium bromide, magnesium iodide and magnesium fluoride; Alkoxy magnesium, such as ethoxy magnesium, isopropyl magnesium, butoxy magnesium, and octoxy magnesium; Alkoxy magnesium chloride, such as methoxy magnesium chloride and ethoxy magnesium chloride; Aryloxy magnesium, such as phenoxy magnesium and methyl phenoxy magnesium; Aryloxy magnesium chlorides such as cy magnesium chloride, methyl phenoxy magnesium chloride and the like. These magnesium compounds may be used alone or in mixture of two or more thereof. Particularly preferred magnesium compounds include magnesium halides.

In step (2), the reaction temperature of the magnesium compound with the organic carboxylic acid ester varies depending on the type of hydrocarbon solvent used. However, the reaction temperature is preferably 50 ° C. or higher and preferably 70 to 200 ° C. The reaction time is 10 minutes. The reaction molar ratio between the magnesium compound and the organic carboxylic acid ester is preferably 0.01 to 1 mole, preferably 0.05 mole per organic mole of magnesium, per mole of magnesium in the magnesium compound. When the magnesium compound is dissolved with an appropriate solubilizer, the particle size of the final solid catalyst can be changed little by little depending on the type of organic carboxylic acid ester, which is a great feature of the present invention.

Examples of organic acid carboxylic acid esters that may be used include methyl formate, methyl acetate, ethyl acetate, propyl acetate, isobutyl acetate, t-butyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butylate, Ethyl valerate, ethyl pyruvate, ethyl fibrate, methylchloro acetate, ethyl dichloro acetate, methyl methacrylate, ethyl crotonate, methylcyclohexyl carboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl Benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, methyl toluate, ethyl benzoate, ethyl ethylene zonate, methyl anate, ethyl aniseate, ethyl ethoxy benzoate, monomethyl phthalate Monoethyl phthalate, dimethyl phthalate Latex, methylethyl phthalate, monoisobutyl phthalate, diethyl phthalate, ethyl isobutyl phthalate, di-propyl phthalate, diisopropyl phthalate, ethyl isobutyl phthalate, din-heptyl phthalate, din-ethylhexyl phthalate, di n-octyl phthalate, diopentyl phthalate, didecyl phthalate, benzyl butyl phthalate, diphenyl phthalate, diethyl naphthalene dicarboxylic acid salt, dibutyl naphthalene dicarboxylic acid salt, and the like.

The reaction between the magnesium compound and the organic carboxylic acid ester is effective in an appropriate hydrocarbon solvent. It is preferable to select a hydrocarbon solvent which does not participate in the reaction at all and can only serve as a simple dispersant. Examples of the hydrocarbon solvents include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane and kerosine and alicyclic hydrocarbons such as cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane and cyclooctane. have.

As described above, in order to obtain a catalyst having a uniform particle size, a method of dissolving a magnesium compound with an appropriate dissolving agent may be used for the following reaction. Examples of suitable dissolving agents include alcohol, organic carboxylic acid, aldehyde, and amine. . The temperature and time of the dissolution reaction vary depending on the type of solubilizer used, but the temperature is generally 80 to 200 ° C., and the time is appropriate for 30 minutes to 3 hours. 0.1 mol or more, preferably 1 mol or more, of a dissolving agent per mole of magnesium is preferable. Specific examples of the dissolving agent include 2-methylpentanol, 2-ethylbutanol, n-heptanol, n-octanol, and 2-ethylhexane. Aliphatic alcohols such as ol, decanol, dodecanol and tradecyl alcohol, alicyclic alcohols such as cyclohexanol and methylcyclohexanol, aromatic alcohols such as benzyl alcohol and methylbenzyl alcohol; caprylic acid; Organic carboxylic acids such as 2-ethylhexanoic acid and octanoic acid; aldehydes such as capryl aldehyde, 2-ethylhexyl aldehyde and octyl aldehyde; heptyl amine, octylamine, decyl amine and 2-ethylhexyl It may be mentioned amines such as Min.

According to the present invention, a magnesium compound (B) comprising a liquid titanium compound (A) having a low titanium concentration produced by step (1) as described above and the organic carboxylic acid ester obtained in step (2) is obtained. By catalytic reaction [step (3)], a catalyst composition having a specific composition of the present invention can be obtained. The catalytic reaction conditions have a great influence not only on the size and shape of the catalyst, but also on the distribution and loading of titanium components in the catalyst. In particular, the dissolution of the magnesium compound by the solubilizer is more influenced. Thus, various types of catalysts can be prepared by adjusting the contact reaction conditions.

As described above, the contact reaction between a liquid titanium compound (A) having a low titanium concentration and a magnesium compound (B) including an organic carboxylic acid ester is the most influential part in determining the catalytic properties. Factors that have a significant effect are temperature, pressure, time, and the molar ratio of titanium and magnesium.

It is effective to keep the rate of contact reaction as slow as possible to produce a catalyst with uniform properties. The reaction temperature suitable for this purpose varies slightly depending on the nature of the material used, but preferably -80 to 50 ° C. The molar ratio of titanium to magnesium in the contact reaction between titanium compound (A) and magnesium compound (B) is about 0.05 to 10 moles of magnesium per mole of titanium in each compound, preferably 0.1 to 5 moles. to be.

In the case of general slurry and gas phase polymerization reaction, the polymerization temperature is about 50 ° C. or higher, and the catalyst according to the present invention is also effective at 50 ° C. or higher, so it is necessary to undergo a aging step at high temperature to give thermal stability of the catalyst after the contact reaction is finished. The suitable temperature is from 50 to 200 ° C., preferably from 70 to 130 ° C. Depending on the material used, in particular the type of hydrocarbon solvent, this temperature can be fluid and the reaction pressure is temperature dependent. The pressure is suitably from atmospheric pressure to 1Kg / cm ² · G. The time from the contacting reaction to the ripening step should be set so that the titanium compound is sufficiently strongly supported in the magnesium compound to maintain stability for a long time at high temperature. Time, preferably 5 to 15 hours. To prepare a catalyst with more uniform properties, An electron donor can also be processed prior to fermentation step.

The catalyst of the present invention prepared by the above method needs to be washed with an inert hydrocarbon to remove unreacted substances from the used compounds including the unreacted titanium compound before use in the polymerization reaction. It is desirable to use as much as possible and to wash as many times as possible to cancel the residual amount of unreacted material.

After the washing process, the inert hydrocarbons are removed and dried in a nitrogen atmosphere to obtain a titanium catalyst supported on a solid magnesium compound. Among the obtained solid catalyst components, the magnesium component is 10 to 30% by weight, preferably 15 to 25% by weight. The titanium component is 1 to 10% by weight, preferably 2 to 7% by weight. The organic carboxylic acid ester as an electron donor is 5 to 30% by weight and preferably 10 to 25% by weight of the catalyst component.

Electron micrographs show that the catalyst according to the present invention exhibits almost spherical particles, with a specific surface area of 100 to 1000 m ² / g. The solid catalyst particles have an almost uniform size with an average particle diameter of 1 to 15 μm, more precisely 3 to 10 μm.

The catalyst according to the present invention having the above characteristics can be used for the polymerization of ethylene and an α-olefin having 3 to 8 carbon atoms. The polymerization reaction can be carried out using the above-described catalyst of the present invention and the organic compounds of the Group I-III metals on the periodic table, and the organic compounds of the Group I-III metals can be used in the polymerization reaction. It may be appropriately selected depending on the nature of the catalyst of the invention.

An organic compound of a group I-III metal generally refers to a material having at least one MC bond in the molecule (M means a group I-III metal), and specific examples thereof include triethyl aluminum, tributyl aluminum, and the like. Trialkenyl aluminum, such as alkyl aluminum, triisoprenyl aluminum, diethyl aluminum ethoxide, and dibutyl aluminum butoxide etc. Alkyl aluminum sesquichloride, such as dialkyl aluminum alkoxide, ethyl aluminum sesquichloride, and butyl aluminum sesquichloride , Dialkyl aluminum hydrides such as dimethyl aluminum hydride and dibutyl aluminum hydride, alkyl aluminum dihydrides such as ethyl aluminum dihydride and propyl aluminum dihydride, ethyl aluminum ethoxy chloride, ethyl aluminum butoxy chloride and Ethyl egg It may be an alkyl aluminum alkoxy halides such as ethoxy minyum bromide.

The use ratio of the catalyst according to the present invention and the organometallic compound during the polymerization reaction may vary depending on the type of α-olefin used, the inert solvent, the polymerization conditions such as temperature, pressure and the like. Generally, the aluminum in the organometallic compound per mole of titanium in the catalyst of the present invention is in the range of 5 to 500 moles, preferably 20 to 300 moles.

In the case of a polymerization reaction of α-olefins having 3 or more carbon atoms, a substance generally called an external electron donor may be further added to the reaction system in addition to the catalyst and the organometallic compound to improve the stereospecificity of the polymer. Examples thereof include organic acid esters, carboxylic acids, acid amides, acid anhydrides, ethers, ethylene glycol derivatives, amines and amides. Preferred of these are organic carboxylic acid esters, especially aromatic carboxylic acid esters. Examples of these include methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octel benzoate, cyclohexyl benzoate, Phenyl benzoate, benzyl benzoate, methyl toluate, ethyl toluate, amyl toluate, monoethyl phthalate, dimethyl phthalate, methyl ethyl phthalate, monoisobutyl phthalate, diethyl phthalate, ethyl isobutyl phthalate, din-propyl phthalate Diisopropyl phthalate, din-butyl phthalate, diisobutyl phthalate, din-heptyl phthalate, di2-ethylhexyl phthalate, and din-octyl phthalate. 0.01 to 5 moles, preferably 0.05 to 3 moles, per mole of titanium in the catalyst.

The temperature of the polymerization reaction for polymerizing ethylene and α-olefin having 3 to 8 carbon atoms by the slurry polymerization method using the catalyst according to the present invention is about 25 to 200 ℃, preferably 40 to 150 ℃, the reaction pressure is from atmospheric pressure to 50Kg / cm ² · good to keep in G. in the case of slurry polymerization can be used as a reaction inert hydrocarbon solvent medium, and wherein it is effective to keep the amount of titanium in the reaction medium, the catalyst per 1ℓ of 0.001 to 1 mmol. If Depending on the ethylene and the α-olefin having 3 to 8 carbon atoms, a molecular weight regulator such as hydrogen may be introduced into the reactor.

Ethylene and C3-C8 polymers polymerized using the catalyst according to the present invention and polymerized by the above-described polymerization method have a spherical form with good flowability and narrow particle size distribution. By changing the polymer, a polymer having a different average particle size can be obtained. For example, when the ethylene is polymerized by the slurry polymerization method using the catalyst according to the present invention, the average particle diameter of the polymer obtained can be changed to about 50 to 500 μm. have. In addition, since the polymer is a spherical particle having good fluidity, it does not have to go through the granulation process, and in this respect, it is very advantageous compared to the existing polymer.

Another advantage that can be obtained when the polymerization is carried out using the catalyst according to the present invention is that copolymerization is excellent for at least two ethylene and α-olefins having 3 to 8 carbon atoms, for example, ethylene and butene-1 content. Can be raised to more than 100wt%. Thus, for ethylene polymerization can produce a polymer having an extremely wide density range with only one kinds of the catalyst system, for example, the present invention in the catalyst system in a density of about ³ from ethylene density of about 0.930g / cm ³ Opole 0.970g / cm by using For example, it is possible to polymerize to high density polyethylene.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1.

[Production of Catalyst]

Replace the inside with nitrogen in a four-necked flask equipped with a stirrer, add 40 ml of kerosene, 9.52 g (0.1 mole) of anhydrous magnesium, and 40 ml of n-octyl alcohol, and mix at room temperature. After the reaction, the reaction product became a colorless and homogeneous solution. The reaction was continued for 2 hours by adding 13 mmoles of diisobutyl phthalate (DIBP) while maintaining the temperature at 130 ° C., and then cooling the reactor to room temperature. In another reactor, 30 ml of titanium tetrachloride and 270 ml of kerosene were mixed and maintained at 0 ° C., and the homogeneous solution was added dropwise over 30 minutes. Then, the temperature of the reactor was raised to 110 ° C. and the reaction was carried out at this temperature for 2 hours. At this time, the stirring speed of the reactor was then 750 rpm. This process resulted in the formation of a yellowish catalyst component. The reactor was then cooled to room temperature to complete the reaction. Washed with kerosene until it is removed to prepare a dry solid catalyst in a nitrogen atmosphere. The titanium content of the catalyst was 3.0% by weight results as measured with a UV-VIS spectrophotometer.

[polymerization]

The internal volume 2L autoclave was filled with 1L n-hexane and then 1.5mmole of triethyl aluminum and the catalyst prepared above were introduced with 0.01mmole into the autoclave based on the titanium atom. Then, hydrogen was introduced to be 2.5Kg / cm ² · G. When the temperature reached 70 ° C., ethylene was introduced to maintain the total pressure of 7 Kg / cm ² · G, and polymerization was performed for 2 hours. The polymerization results are shown in Table 1.

EXAMPLES 2-4

The catalyst was prepared by changing the amount of diisobutyl phthalate and the concentration of titanium tetrachloride during the preparation of the catalyst of Example 1 as shown in Table 1, and polymerization was carried out in the same manner as in Example 1. The polymerization results are shown in Table 1. .

[Examples 5-10]

[Production of Catalyst]

Butyl benzoate (BB) was used instead of diisobutyl phthalate during the preparation of the catalyst of Example 1, and the catalyst was prepared by changing its amount and the concentration of titanium tetrachloride as shown in Table 2 to perform polymerization by the polymerization method as described below. It was.

[polymerization]

The internal volume 2L autoclave was charged with 1L of n-hexane and then the catalyst (0.01 mmole based on titanium atoms) and triethylaluminum 1.3mmole (in aluminum) were introduced into the autoclave. The temperature was then raised to 60 ° C and ethylene was introduced. The total pressure was maintained at 6Kg / cm ² · G to perform a polymerization reaction for 2 hours.

Table 2 shows the polymerization results according to each example.

[Examples 11 to 15]

The catalyst was prepared using monomethyl phthalate (MMP) instead of diisobutyl phthalate during the catalyst preparation of Example 1. The polymerization was carried out in the same manner as in Example 1 using this catalyst. The amount of phthalate and the concentration of titanium tetrachloride were changed as in Table 3, and the polymerization results are shown in Table 3.

[Examples 16-17]

Catalysts were prepared using din-butylphthalate (DNBP) instead of diisobutyl phthalate during the catalyst preparation of Example 1, and polymerization was carried out in the same manner as in Example 1 using these catalysts. According to the embodiment, the amount of din-butylphthalate and the concentration of titanium tetrachloride were changed as in Table 4, and the polymerization results are shown in Table 4.

Comparative Example 1

[Production of Catalyst]

7.14 g of anhydrous magnesium chloride was mixed with 200 ml of n-hexane and 22.5 ml of ethane, followed by reaction at room temperature for 2 hours. 10 ml of diethylaluminum chloride was added dropwise to the mixture, followed by reaction for 1 hour. 17 ml of titanium was added to the mixture and reacted at 80 ° C. for 2 hours. Through this process, a solid catalyst was formed, and the solid catalyst was prepared by removing the unreacted substance with n-hexane and drying in a nitrogen atmosphere.

[polymerization]

The polymerization was carried out in the same manner as in Example 1 using the catalyst prepared above. The polymerization results of this Comparative Example are shown in Table 5 in comparison with Examples 10 and 17.

Example 18

[polymerization]

After filling a 4 L autoclave with 2 L of n-hexane, 0.02 mmoles of titanium and 3 mmoles of triethyl aluminum were introduced into the autoclave based on titanium atoms. It was introduced to be G, and the temperature was increased to 70 ° C. When the temperature reached 70 ° C., 30 g of butene-1 and ethylene were introduced to give a total pressure of 7.0 Kg / cm. The reaction was carried out for 2 hours while maintaining G. The polymerization results are shown in Table 6.

[Examples 19-20]

Polymerized under the same conditions as in Example 18 using the same catalyst as in Example 18, with only a total pressure of 6 and 5 Kg / cm It was changed to G. The polymerization results are shown in Table 6.

Example 22

[Production of Catalyst]

10 g of the catalyst prepared in Example 1 was suspended in a mixture of 30 ml of titanium tetrachloride and 170 ml of kerosene, and then maintained at 100 ° C. for 2 hours. The titanium content of the catalyst was measured by UV-VIS spectroscopy. The result was 2.5 wt%.

[polymerization]

After filling 1 liter of n-hexane in an autoclave having an internal capacity of 2 liters, 0.01 mmol, titanium triethylaluminum, and 0.2 mmol of cyclohexyl methyldimethoxysilane were introduced into the prepared catalyst component based on titanium atoms. Next, 0.2 kg of hydrogen was added. / cm When G-filled and the temperature reaches 70 ℃, propylene is introduced and the total pressure is 6Kg / cm The polymerization reaction was carried out for 2 hours while maintaining the G content. The polymerization results are shown in Table 7.

[Examples 23-24]

[polymerization]

The polymerization was carried out as in Example 22, but the hydrogen pressure was 0.15Kg / cm Fixed with G, total pressure of 7,8Kg / cm The polymerization was carried out by changing to G. The polymerization results are shown in Table 7.

Claims (3)

(1) mixing the titanium compound in an inert hydrocarbon solvent in an amount of 5-40% by volume to obtain a low concentration liquid titanium compound (A); (2) treating the magnesium mixture with 0.01 to 3 moles of organic carboxylic acid ester per mole of magnesium compound in an inert hydrocarbon solvent to obtain an organic carboxylic acid ester-containing magnesium compound (B); And (3) contacting the titanium compound (A) obtained in step (1) with the magnesium compound (B) obtained in step (2) in an amount of 0.1 to 10 moles of magnesium per mole of titanium. Process for producing a catalyst composition for producing ethylene and an α-olefin polymer having 3 to 8 carbon atoms. The method of claim 1, wherein in step (2), the magnesium compound is first dissolved in a solubilizer selected from 0.1 moles or more of alcohols, carboxylic acids, aldehydes and amines per mole of magnesium, and then treated with an organic carboxylic acid ester. Method for producing a catalyst composition characterized in that. The method of claim 1, wherein the catalyst composition is used to prepare polyethylene having a density of 0.930 to 0.970 g / cm ³ .