KR101226427B1 - Catalyst compositions for preparing polyolefin, and method for preparing polyolefin having improved escr using the same - Google Patents

Abstract

The present invention relates to a catalyst composition for producing polyolefin and a method for producing polyolefin having improved environmental stress cracking resistance using the same, and more particularly, to a carrier on which a Ziegler-Natta catalyst or a metallocene catalyst is supported. And it relates to a catalyst composition for producing a polyolefin additionally carrying a bifunctional compound having a comonomer function and a method for producing a polyolefin, characterized in that the olefin monomer is polymerized in the presence thereof.

According to the present invention, a catalyst composition for preparing a polyolefin having a bifunctional compound capable of producing a polyolefin having excellent environmental stress crack resistance (ESCR) even when a small amount is used or without using a promoter and a comonomer, and using the same There is an effect of providing a method for producing a polyolefin.

Bifunctional compounds, environmental stress crack resistance (ESCR), polyolefins, carriers, promoters, comonomers

Description

Catalyst composition for polyolefin production and method for producing polyolefin with improved stress cracking resistance using the same {CATALYST COMPOSITIONS FOR PREPARING POLYOLEFIN, AND METHOD FOR PREPARING POLYOLEFIN HAVING IMPROVED ESCR USING THE SAME}

The present invention relates to a catalyst composition for producing a polyolefin and a method for producing a polyolefin having improved environmental stress cracking resistance using the same, and more particularly, to the environmental stress cracking even when a small amount of a promoter and a comonomer are not used. The present invention relates to a catalyst composition capable of producing polyolefins having excellent ESCR and a method for producing polyolefins using the same.

In general, polyolefin resins such as polyethylene or polypropylene are used in various applications due to their excellent moldability, mechanical properties and chemical resistance, and low cost.

The use of the polyolefin resin is subdivided according to its density. At this time, the key factor used for density control may be the amount and type of comonomer used with the monomer. In general, how much comonomer is connected to the side chain in the main chain and the length is determined by the length. The greater the amount of side chains, and the longer the side chains, the lower the density in general.

A common method for linking the comonomer to the polymer backbone is to introduce a comonomer into the polymerization reactor separately from the main and cocatalysts, which allows the comonomer to form side chains by competitively binding to the backbone at the olefin monomer and catalytically active sites. do. The fundamental limitation of this method is that a non-negligible amount of unreacted comonomer and cocatalyst which is not branched must be separated or removed in the post process.

Meanwhile, as the co-monomer, a bifunctional compound capable of embodying a bi-function capable of controlling the density of the polymer attached to the side chain of the polyolefin and introducing a hydrophilic group through an appropriate post-reaction is disclosed. have.

The bifunctional compound includes both an alkylaluminum-based structure serving as a promoter and a carbon double bond (C = C) structure serving as a comonomer, and in theory, the density of a polyolefin resin prepared without adding a separate comonomer Seems to be able to adjust.

However, when a bifunctional compound having both the co-catalyst function and the co-monomer function is used for ethylene polymerization, the co-catalyst function is overwhelmingly expressed rather than the co-monomer function, so that the co-monomer hardly adheres to the side chain. There is a problem that affects only the polymerization capacity of the monomer, ie activity.

Therefore, there is a need for a suitable catalyst system and polymerization system capable of obtaining a polyolefin resin having a desired density and the like while minimizing the amount of comonomers and cocatalysts.

In order to solve the problems of the prior art as described above, the present invention does not use a cocatalyst and a comonomer, or even a small amount of the use of a bifunctional compound capable of producing a polyolefin excellent in environmental stress cracking resistance (ESCR) It is an object of the present invention to provide a catalyst for producing polyolefin, and a method for producing polyolefin using the same.

These and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a catalyst for preparing polyolefin in which a bifunctional compound having a cocatalyst function and a comonomer function is additionally supported on a carrier on which a Ziegler-Natta catalyst or a metallocene catalyst is supported. .

The present invention also provides a method for producing a polyolefin by polymerizing an olefin monomer in the presence of the catalyst for producing the polyolefin.

The catalyst for polyolefin production in which a bifunctional compound is additionally supported on a carrier carrying a Ziegler-Natta catalyst or a metallocene catalyst according to the present invention, and a polyolefin production method using the same, do not use a cocatalyst and a comonomer, or use a small amount thereof. In addition, there is an effect of providing a polyolefin having a low density and excellent environmental stress crack resistance (ESCR).

Hereinafter, the present invention will be described in detail.

The present inventors synthesized the ω-alkenyl aluminum compound, a bifunctional compound having a structure capable of performing the functions of the promoter and the comonomer at one time, and then additionally supported it on the carrier of the supported catalyst to separately input the comonomer or promoter. While minimizing the amount of polyolefin, it was possible to polymerize a polyolefin having excellent environmental stress crack resistance (ESCR).

The catalyst for producing polyolefin of the present invention is characterized in that a bifunctional compound having a cocatalyst function and a comonomer function is additionally supported on a carrier on which a Ziegler-Natta catalyst or a metallocene catalyst is supported.

The bifunctional compound may be an ω-alkenylaluminum compound represented by the following Chemical Formula 1, and preferably, ω-octenyldiisobutylaluminum, ω-hexenylisobutylaluminum or ω-butenyldiisobutylaluminum.

[Formula 1]

AlR ¹ R ² ₂

In Formula 1, R ¹ is alkenyl having 4 to 20 carbon atoms, R ² is the same or different, and is an alkyl group having 2 to 10 carbon atoms which does not have a substituent or is substituted with a halogen element.

The ω-alkenylaluminum compound of Chemical Formula 1 not only serves as a promoter for activating a magnesium-supported Ziegler-Natta catalyst, but also serves as a comonomer for the olefin monomer, thereby controlling physical properties of the polyolefin prepared. The ω-alkenylaluminum compound of Chemical Formula 1 may be prepared by reacting a substituted or unsubstituted aliphatic α, ω-diene or cycloaromatic diene having 4 to 20 carbon atoms with an organoaluminum compound represented by the following Chemical Formula 2 have.

[Formula 2]

AlR ² ₂ X

In the above formula, R ² is the same or different and is an alkyl group having 2 to 10 carbon atoms, and X is hydrogen or a halogen atom.

The diene and the organoaluminum compound of Chemical Formula 2 may be reacted at a molar ratio of 3: 1 to 5: 1. Unlike the conventional synthesis of ω-alkenylaluminum compounds, the amount of reactants is minimized. Too little of the diene compound outside the above range may cause a cyclization reaction.

The reaction of the organoaluminum compound and the diene in the preparation of the ω-alkenylaluminum compound may be carried out in a vacuum state of 40 to 100 ° C., preferably at 50 to 90 ° C., more preferably at about 60 to 80 ° C. 3 to 4 hours, preferably 2 to 3 hours.

In order to prevent the by-products caused by side reactions during the reaction, the reactor is blocked from the outside, and in some cases, when using a glass-based reactor, the reaction is preferably performed under an inert atmosphere. After the reaction, the unreacted diene is separated by vacuum extraction. It is desirable.

When the diene compound has a substituent, the substituent may be a halogen group, an epoxy group, an alkyl group having 2 to 10 carbon atoms, an alkoxy group, an alkyl siloxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 8 carbon atoms.

Specific examples of the diene compound include 1,3-butadiene, 1,4-pentadiene, 1-acetoxy-1,3-butadiene, 1,3-butadiene diepoxide, cis, cis-1,5-cycloocta Dienes, trans, trans-1,4-diphenyl-1,3-butadiene, 1,3-hexadiene, 3-methyl-1,2-butadiene, trans-2-methyl-1,3-pentadiene, hexa Chloro 1,3-butadiene, dicyclopentadiene, 1,9-decadiene, 2-methyl-1,4-pentadiene, bicyclo (2,2,1) hepta-2,5-diene, 1,4 -Cyclohexadiene, 2,4-dimethyl-1,3-pentadiene, butadiene monooxide, 1,5-hexadiene, 1,4-hexadiene, 1,7-octadiene bicyclo (2,2,1 ) Hepta-2,5-diene, cis-1,3-pentadiene, trans-1,3-pentadiene, 1,4-pentadiene, 1,2,3,4,5-pentamethylcyclopentadiene , 2,3-dimethyl-1,3-butadiene, 1,5-cyclo octadiene, bicyclo (4,3,0) nona-3,6-diene, 1,3-cycloheptadiene, 1,1, 4,4-tetraphenyl-1,3-butadiene, 1,2-butadiene, 5 , 5-dimethoxy-1,2,3,4-tetrachloro cyclopentadiene, trans-1-methoxy-3- (trimethylsiloxy), 1,2,3,4,5-pentamethyl cyclopentadiene , 1-methoxy-1,4-cyclohexadiene, 1-methoxy-1,3-cyclohexadiene, 1- (trimethylsiloxy) -1,3-butadiene, 1,5-cyclooctadiene, 3 , 3,6,6-tetramethoxy-1,4-cyclohexadiene, 1,6-heptadiene, 1,8-nonadiene, 1-methyl-1,4-cyclohexadiene, 3-methyl-1 From 4-pentadiene, cis, cis-1,3-cyclooctadiene, 2,3-dimethoxy-1,3-butadiene, and trans-2-methyl-1,3-pentadiene It may be any one selected.

The carrier is not particularly limited, but is preferably a magnesium carrier in the case of a Ziegler-Natta catalyst and a silica carrier in the case of a metallocene catalyst.

The magnesium-supported Ziegler-Natta catalyst may be prepared by contacting a solid anhydrous magnesium carrier with a titanium compound represented by the following Formula 3 in a polar solvent that does not chemically react with a nonpolar solvent or a compound used in the catalyst synthesis process. have.

(3)

Ti (OR ³ ) _ℓ Y _4-ℓ

In Formula 3, R ³ is an alkyl group having 1 to 10 carbon atoms, each of two or more is the same or different, Y is a halogen element, L is an integer of 0 to 4.

R ³ is an alkyl group having 2 to 8 carbon atoms, preferably an alkyl group having 3 to 5 carbon atoms, Y is Br, Cl, preferably Cl, and L is an integer of 0 to 4.

The titanium compound represented by the formula (3) is preferably titanium tetrachloride or chlorinated titanium oxide.

The titanium compound may be added to the slurry by itself, but is preferably added in a dissolved state in a suitable solvent such as a nonpolar solvent.

As a preferable example of the nonpolar solvent, isobutane, pentane, hexane, n-heptane, octane, nonane, decane and isomers thereof, aliphatic compounds such as cyclohexane, aromatic compounds such as benzene, toluene, ethylbenzene, and the like can be used. . The most commonly used nonpolar solvent is hexane.

The non-polar solvent may be purified by a suitable method to remove substances that affect the catalytic activity, such as water, oxygen, polar compounds.

Magnesium halide may be used as the solid anhydrous magnesium carrier, and may include dihalogenated magnesium such as magnesium chloride, magnesium iodide, magnesium fluoride or magnesium bromide; Alkylmagnesium halides such as methyl magnesium halide, ethyl magnesium halide, propyl magnesium halide, butyl magnesium halide, isobutyl magnesium halide, hexyl magnesium halide or amyl magnesium halide and the like; Alkoxymagnesium halides such as methoxy magnesium halide, ethoxy magnesium halide, isopropoxy magnesium halide, butoxy magnesium halide or octoxy magnesium halide; Aryloxymagnesium halides such as phenoxy magnesium halide or methylphenoxy magnesium halide;

Two or more of the magnesium halides may be mixed and used, and it is also effective to be used in the form of a complex with another metal.

When preparing the magnesium-supported Ziegler-Natta catalyst, a donor may be additionally added to control the isotacticity which affects physical properties such as the rigidity of the polymer. By appropriately selecting the donor, an olefin polymer of desired stereoregularity and physical properties can be obtained.

The donor is not particularly limited as long as it is commonly used to control the stereoregularity of the olefin polymer, and may be appropriately selected as necessary.

The compounds used in the preparation of the magnesium-supported Ziegler-Natta catalyst should be at least partially soluble in the solvent and liquid at the reaction temperature in the preparation of the catalyst.

As the solid anhydrous magnesium carrier, a particle size of 0.1 to 200 μm in the form of spherical fine particles may be used, and preferably 10 to 150 μm may be used, and anhydrous magnesium chloride having a moisture content of less than 1% may be used. It is desirable to.

The solid anhydrous magnesium carrier and the titanium compound represented by Formula 3 may be used in a molar ratio of 1: 1 to 1:50, preferably 1: 1 to 1:10.

As a method of additionally supporting the ω-alkenylaluminum compound on the magnesium-supported Ziegler-Natta catalyst, the ω-alkenyl aluminum compound is directly supported by a magnesium-supported Ziegler-Natta catalyst and supported by ω-al There is a method in which the organoaluminum compound and the diene, which are raw materials used in the production of the kenyl aluminum compound, are sequentially contacted with a magnesium-supported Ziegler-Natta-based catalyst, and as a result, the ω-alkenyl aluminum compound is synthesized and supported on a magnesium carrier. In this case, the contact order may be determined in consideration of the characteristics of the carrier surface.

It is preferable that both the above methods proceed under the following conditions.

The ω-alkenyl aluminum compound may be used in an amount of 10: 1 to 1,000: 1 based on the molar ratio of aluminum to titanium, and preferably 100: 1 to 300: 1. The molar ratio of final supported aluminum to titanium may be from 1: 1 to 300: 1, more preferably from 30: 1 to 150: 1.

The contact temperature may be -20 ° C to 200 ° C, preferably 0 ° C to 50 ° C.

The contact time is determined according to the content of the reactants and the contact temperature, and may usually take several tens of minutes to several tens of hours.

After completing the contact reaction, the bifunctional compound additionally supported catalyst can be used as it is without washing, it is preferred to use after removing the unreacted matter through a separate washing process. When used after removing the unreacted material, it is advantageous in controlling the properties of the reaction process and the final product.

As the washing liquid used in the washing process, a hydrocarbon compound which is a commonly used inert solvent may be used.

After the washing process, the catalyst additionally loaded with the bifunctional compound may be dried under a vacuum of 10 to 200 ℃, preferably to be dried at 50 to 100 ℃.

When the drying process is carried out, all of the bi-functionality of the supported ω-alkenyl aluminum compound is properly exhibited, thereby making a polyolefin resin having a relatively low density and excellent environmental stress crack resistance. It is shown that when the drying process, the carrier and the ω-alkenyl aluminum compound are more firmly bonded.

Polyolefin production method of the present invention is characterized in that the polymerization of the olefin monomer in the presence of the catalyst for producing polyolefin.

When the olefin is polymerized using the catalyst for producing polyolefin, the prepolymerization step may be performed. Through this, it is possible to prevent the destruction of the catalyst structure due to the rapid reaction at the beginning of the polymerization, and also to prevent the supported bifunctional compound from leaving the medium. When the bifunctional compound is released from the carrier, only the cocatalyst function is mainly exerted, making it difficult to obtain the physical properties of the desired polyolefin.

As a specific example of the prepolymerization step, when the organoaluminum compound is used as the prepolymerization promoter, the molar ratio (Al / Ti) of aluminum in the prepolymerization promoter to titanium in the catalyst for producing the polyolefin may be 1 to 100. It is used so that it may become 1-50, More preferably, it uses so that it may become 5-20. In this case, the prepolymerization temperature may be -50 to 100 ° C, preferably -10 to 20 ° C, and the prepolymerization pressure may be 30 atm or less, and preferably 3 atm or less.

The olefin polymerization may be carried out through slurry phase or gas phase polymerization.

The slurry phase polymerization may be carried out under a solvent which is a olefin itself or a medium which is a monomer.

The olefins may be used alone or in combination of two or more, and include ethylene, alpha olefins having 2 to 20 carbon atoms such as propylene, 1-butene, 1-pentene, 1-hexene, 1,3-butadiene, 1,4- Diolefins of 4 to 20 carbohydrates such as pentadiene, 2-methyl-1,3-butadiene, 1,5-hexadiene, 1,7-octadiene, cyclopentene, cyclohexene, cyclopentadiene, An alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen, or a cycloolefin having 5 to 20 carbon atoms such as cyclohexadiene, norbornene, and methyl-2-norbornene or a cyclodiolefin, styrene, or a benzene ring Substituted styrene combined with a group, an amine group, a silyl group, a halogenated alkyl group and the like can be included.

In the olefin polymerization, a separate cocatalyst may be additionally added, and available cocatalysts include triethylaluminum (TEA), triisobutylaluminum (TIBA), tributylaluminum, trihexylaluminum, trioctyl aluminum, and the like. Alkyl aluminum compounds; ω-alkenyl aluminum compound; And a diene compound and a dialkylaluminum halide (or a dialkylaluminum hydride); may be at least one selected from the group consisting of: a ω-alkenyl aluminum compound and a group consisting of a diene compound and a dialkylaluminum halide. It is 1 or more types chosen from.

The ω-alkenyl aluminum compound used as the cocatalyst is preferably ω-octenyldiisobutylaluminum, ω-hexenylisobutylaluminum or ω-butenyldiisobutylaluminum. The molar ratio of the added cocatalyst) and titanium may be used in the range of 10 to 1,000, preferably used in the range of 50 to 500, more preferably in the range of 100 to 400.

The polymerization temperature is not particularly limited, but may be -50 to 200 ℃, preferably 0 to 150 ℃.

The polymerization pressure may be usually 1.0 to 3,000 atm, preferably 1 to 1,000 atm, and the polymerization may be batch, semi-continuous or continuous.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

Example

< Bifunctional  Compound (hereinafter, BFCC Manufacturing of>

The 20-liter reactor was replaced with a nitrogen atmosphere, 3.7 L of 1,7-octadiene and 1.5 L of diisobutylaluminum hydride (hereinafter referred to as DiBAH) were sequentially added, and the temperature was raised to 80 ° C. for 2 hours. . After the reaction, the solution was cooled to room temperature, and unreacted 1,7-octadiene was removed using a vacuum to obtain? -Octenyldiisobutylaluminum.

Example  One

<Support magnesium Ziegler - Appear  Preparation of Catalyst

28.5 g of MgCl ₂ and 148.5 mL of 2-ethyl-hexanol were added to a 1 L glass reactor equipped with a magnetic stirrer (manufactured by Buchi), and then the total volume of the reaction solution was adjusted to 650 mL by adding hexane, and the reactor temperature was 130 It heated up at ° C and stirred for 3 hours at 200 rpm. After lowering the reactor temperature to 35 ° C, 178 mL of TiCl ₄ was injected for 4 hours, and then 4.5 mmol of diisobutylphthalate was added to the donor at the same temperature, and the temperature of the reactor was raised to 110 ° C to 300 rpm. The reaction was carried out for 2 hours with stirring.

After the reaction, the temperature of the reactor was cooled to 35 ° C. to precipitate a solid component, and the supernatant was filtered and washed twice with hexane.

150 mL of TiCl ₄ was further added to the washed solid, the total volume of the reaction solution was adjusted to 500 mL with hexane, and the reactor temperature was raised to 130 ° C. and stirred at 300 rpm for 2 hours. Thereafter, the reactor temperature was cooled to 80 ° C. to precipitate a solid component, and the supernatant was filtered out. It was then washed four times with hexane and dried under vacuum at 50 ° C. to obtain a magnesium-supported Ziegler-Natta catalyst with 1.7 wt% Ti, 20.2 wt% Mg and 11.3 wt% internal electron donor.

< Bifunctional  The compound Supported Polyolefin  Manufacturing Catalyst>

1 g of the magnesium-supported Ziegler-Natta catalyst was placed in a 200 ml flask, and 15 ml of ω-octenyldiisobutylaluminum and 100 ml of hexane were added and stirred for 12 hours.

The filtrate was then removed, 100 ml of hexane was added, then stirred at 80 ° C. for 2 hours, the temperature was lowered below 50 ° C. and the filtrate was removed.

100 ml of hexane was added to the flask from which the filtrate was removed, stirred at 80 ° C. for 2 hours, the temperature was lowered to 50 ° C. or lower, the filtrate was removed and dried in vacuo at 80 ° C., and 4.63 g of a bifunctional compound was carried in a glove box. A catalyst for preparing polyolefin was prepared.

The catalyst for preparing polyolefin on which the bifunctional compound is supported includes 3.08 mmol of ω-octenyldiisobutylaluminum per gram.

<Production of Polyethylene Resin>

The inside of the 5 L stainless steel autoclave was heated to 80 ° C., and then packed and purged with argon several times to remove water and air that could act as catalyst poisons, and vacuum dried. In a vacuum dried state, 3 liters of purified normal hexane was charged, and 3.34 mmol of ω-octenyldiisobutylaluminum was added as a cocatalyst, followed by stirring for several minutes.

After the temperature of the autoclave was raised to 3 ° C. lower than the reaction temperature, 0.11 g (1.54 mmol of a supported bifunctional compound) of a polyolefin-producing catalyst was injected while stirring was stopped.

Hydrogen and ethylene passed through the trap for water and oxygen removal connected to the injection line were filled so that the pressure ratio (P_H ₂ / P_C ₂ H ₄ ) was 0.76, the total pressure of the autoclave was 8.5 bar, and polymerization was carried out while stirring at 80 ° C. It was.

After 2 hours, stirring was stopped and the unreacted material was removed under reduced pressure, and the temperature was lowered to room temperature while restirring.

The produced polymer slurry was filtered through an aspirator, and then dried under vacuum at 80 ° C. for at least 12 hours to obtain a polyethylene resin.

Example  2

Example 1 except that 10.8 mmol of ω-octenyldiisobutylaluminum was used as a co-catalyst in the preparation of the polyethylene resin of Example 1 and the pressure ratio of hydrogen and ethylene (P_H ₂ / P_C ₂ H ₄ ) was 0.60. It was carried out in the same manner as.

Example  3

The preparation was carried out in the same manner as in Example 1, except that no cocatalyst was used to prepare the polyethylene resin of Example 1.

Example  4

Example 1 except that 3.08 mmol of the polyolefin-supported catalyst for preparing the polyfunctional resin and 0.22 g (3.34 mmol) of ω-octenyldiisobutylaluminum as a co-catalyst in the preparation of the polyethylene resin of Example 1 It carried out in the same way.

Example  5

In preparing the polyethylene resin of Example 1, 0.055 g (0.77 mmol) of a catalyst for preparing a polyolefin carrying the bifunctional compound, 21.6 mmol of DiBAH as a cocatalyst and 1,7-octadiene as a comonomer (the cocatalyst DiBAH Was added to an autoclave and stirred at 80 ° C. for 1 hour).

Example  6

When preparing the polyethylene resin of Example 1, except that 0.077 g (1.08 mmol) of the catalyst for preparing polyolefins carrying the bifunctional compound and 21.6 mmol of ω-octenyldiisobutylaluminum as a promoter were used. It carried out in the same way.

Comparative example  One

In preparing the polyethylene resin of Example 1, 0.134 g of the magnesium-supported Ziegler-Natta catalyst and the co-catalyst, ω-octenyldiisobutylaluminum, which was not supported with the bifunctional compound, instead of the catalyst for preparing the polyolefin having the bifunctional compound, 3.34 mmol Except that was used in the same manner as in Example 1 above.

Comparative example  2

In preparing the polyethylene resin of Example 1, 0.11 g of the magnesium-supported Ziegler-Natta catalyst, which is not supported by the bifunctional compound, instead of the catalyst for preparing the polyolefin having the bifunctional compound, 3.34 mmol of triethylene aluminum and 3.34 mmol of octene as a promoter. Except that was used in the same manner as in Example 1 above.

The physical properties of the polyethylene resins prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were measured by the following method, and the results are shown in Table 2 below.

Apparent Density—Measured using an Apparent Density Tester 1132 by the method specified in DIN 53466 and ISO R 60.

* Melt Index of Polymer (Melt Index, MI)-measured at 190 ° C and 2.16 kg load according to ASTM D-1238.

* Environmental Stress Cracking Resistance (ESCR)-Time to F50 (50% fracture) was measured under 50 ℃ using 10% Igepal CO-630 solution according to ASTM D1693.

* IZOD impact strength-measured at room temperature according to ASTM D256.

TABLE 1

division Support condition Polymerization conditions BFCC Supported BFCC Al promoter Comonomer usage
mmol Loading
mmol Total amount
mmol Actual support
mmol Kinds mmol Kinds mmol Example 1 50 18 1.54 1.54 BFCC 3.34 - - Example 2 50 18 1.54 1.54 BFCC 10.8 - - Example 3 50 18 1.54 1.54 - - - - Example 4 50 18 3.08 3.08 BFCC 3.34 - - Example 5 50 18 0.77 0.77 DiBAH 21.6 1,7-octadiene 64.8 Example 6 50 18 1.08 1.08 BFCC 21.6 - - Comparative Example 1 - - - - BFCC 3.34 - - Comparative Example 2 - - - - TEA 3.34 Octene 3.34

[ Table 2 ]

division Properties Density (g / ml) MI (g / 10min) ESCR (hrs) IZOD (kgcm / cm) Example 1 0.954 2.15 15 13 Example 2 0.954 2.18 13 7 Example 3 0.953 2.23 14 7 Example 4 0.955 3.28 18 7 Example 5 0.952 2.97 25 10 Example 6 0.957 2.06 12 14 Comparative Example 1 0.961 2.62 4 6 Comparative Example 2 0.961 2.82 6 6

As shown in Table 2 above, when polyethylene is prepared using a catalyst for preparing polyolefin in which ω-octenyldiisobutylaluminum, which is a bifunctional compound, is additionally supported on a magnesium-supported Ziegler-Natta catalyst (Examples 1 to 6), As compared with the case of using only free ω-octenyldiisobutylaluminum (Comparative Example 1) or triethylaluminum (TEA) (Comparative Example 2), it was confirmed that a polyethylene resin having a low density and remarkably excellent environmental stress crack resistance was produced.

Claims (14)

A) a magnesium supported catalyst comprising a Ziegler-Natta catalyst supported on a bifunctional compound, and b) a bifunctional compound promoter, The cocatalyst of b) is included in an amount of 3.34 to 10.8 mmol per 0.11g of a), or 21.6 mmol per 0.077g of a), The Ziegler-Natta catalyst is a compound represented by the following formula (3), (3) Ti (OR ³ ) _ℓ Y _4-ℓ (In the above formula (3), R ³ is an alkyl group having 1 to 10 carbon atoms, each of the two or more are the same or different, Y is a halogen element, l is an integer of 0 to 4), Bifunctional compounds in a) and b) are characterized in that the ω-alkenylaluminum compound Catalyst composition for producing polyolefin. delete delete delete delete The method of claim 1, The ω-alkenyl aluminum compound is ω-octenyl diisobutyl aluminum, ω-hexenyl isobutyl aluminum, or ω-butenyl diisobutyl aluminum Catalyst composition for producing polyolefin. The method of claim 1, The a) and b) in the bifunctional compound is characterized in that the molar ratio of the metal in the bifunctional compound and the titanium in the Ziegler-Natta-based catalyst is used in the content range of 10: 1 to 1,000: 1 Catalyst composition for producing polyolefin. delete The method of claim 1, The magnesium-supported Ziegler-Natta catalyst of a) further comprises a donor for controlling stereoregularity. Catalyst composition for producing polyolefin. A polymerizable olefin monomer is prepared by using the catalyst composition for preparing polyolefin according to any one of claims 1, 6, 7, or 9, wherein the olefin monomer is polymerized while adjusting the pressure ratio of hydrogen and ethylene to 0.60 to 0.76. step; Characterized in that consists of Method for producing polyolefin with improved environmental stress crack resistance. delete delete delete The method of claim 10, Polymerization of the olefin monomer is characterized in that the pre-polymerization first Method for producing polyolefin with improved environmental stress crack resistance.