KR101845626B1 - Process for preparing polyolefin and polyolefin prepared thereby - Google Patents

Abstract

The present invention relates to a method for preparing a polyolefin, and to a polyolefin prepared therefrom, wherein the method for preparing a polyolefin comprises the following steps: (a) polymerizing a first olefin-based monomer to prepare a first olefin polymer; and (b) polymerizing the second olefin-based monomer to prepare a second olefin polymer, and mixing the first olefin polymer and the second olefin polymer, wherein the second olefin polymer has a weight average molecular weight, a z-average molecular weight, and a comonomer content higher than the same of the first olefin polymer, and the first olefin polymer and the second olefin polymer are prepared in the presence of a specific catalyst. An object of the present invention is to provide the method for preparing the polyolefin having a high molecular weight content and an excellent comonomer distribution, and having excellent mechanical properties and processability.

Description

PROCESS FOR PREPARING POLYOLEFIN AND POLYOLEFIN PREPARED THEREBY BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a polyolefin,

The present invention relates to a process for the production of polyolefins and to polyolefins prepared therefrom.

Polyolefins should have excellent mechanical properties such as toughness and strength in molding products for specific use. Particularly, when the polyolefin is molded into a blow-molded container, it is required to have excellent environmental stress cracking resistance due to its mechanical properties. Such mechanical properties can be improved by increasing the molecular weight or adjusting the comonomer content, but when the molecular weight is increased, the viscosity increases and the processability of the polyolefin is lowered.

In order to solve such a problem, various attempts have been made in the past to produce polyolefins having excellent mechanical properties and processability. As one of them, U.S. Patent No. 4,530,914 describes a method for producing a polyolefin having a broad molecular weight distribution by using a metallocene catalyst composition in which two or more components are mixed. However, this method has limitations in producing polyolefins having desired physical properties because two or more components mixed in the catalyst composition may differ in hydrogen and comonomer reactivity with each other and it is difficult to control their reactivity respectively. Further, even when a polyolefin having a broad molecular weight distribution is produced by using a metallocene catalyst, it is difficult to sufficiently improve machinability and mechanical properties. In another, U.S. Published Patent Application No. 2011-0306737 describes a method for producing polyolefins having multiple compositions using Ziegler-Natta catalysts. However, since this method uses a Ziegler-Natta catalyst, the polymerization activity is low and a large amount of the catalyst must be used, and there is a limitation in obtaining polyethylene having desired mechanical properties. Therefore, much research is still required in improving the mechanical properties and processability of polyolefins.

In order to solve the above problems, it is an object of the present invention to provide a method for producing a polyolefin having a high molecular weight content and an excellent comonomer distribution, and having excellent mechanical properties and processability.

It is another object of the present invention to provide a polyolefin produced by the above production process.

In order to achieve the above object, the present invention provides a process for producing a polyolefin resin, comprising the steps of: (a) polymerizing a first olefin-based monomer to prepare a first olefin polymer; And (b) polymerizing the second olefin-based monomer to prepare a second olefin polymer, and mixing the first olefin polymer and the second olefin polymer, wherein the second olefin polymer comprises the first olefin polymer Wherein the first olefin polymer and the second olefin polymer are produced in the presence of a catalyst having a weight average molecular weight, a z-average molecular weight and a comonomer content higher than those of the first olefin polymer and the second olefin polymer, A process for producing a polyolefin is provided.

[Chemical Formula 1]

(In the formula 1,

M is selected from the group consisting of Group 3 to Group 10 elements on the periodic table,

X is a halogen, an amine group, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl A silyl group, a silyl (C ₆ -C ₂₀ ) aryl group, a (C ₁ -C ₂₀ ) alkoxy group, a (C ₁ -C ₂₀ ) alkylsiloxy group and a (C ₆ -C ₂₀ ) aryloxy group ,

n is an integer of 1 to 5,

Ar ¹ and Ar ² are the same or different and are each independently a ligand having a cyclopentadienyl skeleton wherein the ligand is selected from the group consisting of halogen, (C ₁ -C ₂₀ ) alkyl, (C ₃ -C ₂₀ ) (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl ( (C ₁ -C ₂₀ ) alkyl group, (C ₁ -C ₂₀ ) alkyl (C ₆ -C ₂₀ ) aryl group, (C ₆ -C ₂₀ ) arylsilyl group and silyl (C ₆ -C ₂₀ ) And when the substituent is plural, they may be the same or different from each other, and the substituent may be combined with adjacent adjacent substituents to form a ring.

In addition, the present invention provides a polyolefin produced by the above production method.

The present invention relates to a process for producing an olefin polymer by using a specific catalyst and producing a polyolefin by mixing two kinds of olefin polymers having different weight average molecular weights, z-average molecular weights and comonomer contents, whereby a high molecular weight content and a comonomer distribution It is possible to provide a polyolefin which is excellent in mechanical properties (particularly, pressure resistance characteristics).

1 shows the results of measurement of the molecular weight distribution of polyethylene according to one embodiment of the present invention and a comparative example.
FIG. 2 shows the results of measurement of the comonomer distribution of polyethylene according to one embodiment of the present invention and a comparative example.

Conventionally, in order to produce a polyolefin having excellent mechanical properties and processability, a catalyst composition in which two or more components are mixed is used, or a multi-composition is prepared using a Ziegler-Natta catalyst. However, there is a limit in controlling the molecular weight distribution of the polyolefin, and the Ziegler-Natta catalyst has a limitation in controlling the polymerization activity, and thus it is difficult to produce a polyolefin having excellent mechanical properties and processability have.

Accordingly, in the present invention, by mixing the two olefin polymers having different weight average molecular weights, z-average molecular weights and comonomer contents using a metallocene catalyst, the molecular weight distribution and comonomer distribution can be easily controlled, Thereby producing a polyolefin having stress cracking property.

<Production method of polyolefin>

According to one embodiment of the present invention, a method for producing a polyolefin includes the steps of: (a) polymerizing a first olefin-based monomer to prepare a first olefin polymer; And (b) polymerizing the second olefin-based monomer to prepare a second olefin polymer, and mixing the first olefin polymer and the second olefin polymer. Wherein the second olefin polymer has a weight average molecular weight, a z-average molecular weight, and a comonomer content higher than that of the first olefin polymer, and the first olefin polymer and the second olefin polymer satisfy the following formula In the presence of a catalyst comprising a catalytic compound.

At this time, the first olefin polymer and the second olefin polymer may be respectively produced in a single reactor or may be produced in separate reactors. When the first olefin polymer and the second olefin polymer are produced in separate reactors, the first olefin-based monomer is polymerized in the first reactor to produce the first olefin polymer, and the second olefin-based monomer is polymerized in the second reactor Polymerizing to produce a second olefin polymer; Alternatively, the first olefin polymer may be prepared by polymerizing the first olefin monomer in the first reactor, and the first olefin polymer and the second olefin monomer may be polymerized in the second reactor to produce the second olefin polymer. However, the present invention is not limited only to the steps of the above-described production method, and the steps of each step may be modified or optionally mixed as necessary.

The first olefin-based monomer and the second olefin-based monomer are not particularly limited, and examples thereof include ethylene, propylene, 1-butene, 1-pentene, 1- (C ₂ -C ₂₀ )? -Olefins such as (1-hexene); 1,3-butadiene, 1,4-pentadiene, and 2-methyl-1,3-butadiene. C ₄ -C ₂₀ ) diolefins; Such as C _{3 to} C ₆ , such as cyclopentene, Cyclohexene, Cyclopentadiene, Cyclohexadiene, Norbonene, Methyl-2-Norbonene, ~ C ₂₀₎ cycloolefin (cycloolefin); (C ₄ -C ₂₀ ) cyclodiolefin; A substituted or unsubstituted styrene may be substituted for the benzene ring by a (C ₁ -C ₁₀ ) alkyl group, a (C ₁ -C ₁₀ ) alkoxy group, a halogen, an amine group, a silyl group or a halogenated alkyl group. At this time, the first olefin-based monomer and the second olefin-based monomer may be the same or different from each other, and when two or more olefin monomers are included, they may be the same or different.

The first olefin polymer and the second olefin polymer may be prepared by polymerization in a slurry phase, a solution phase, a gas phase, or a bulk phase.

When the polymerization reaction is carried out in a liquid phase or a slurry, the solvent or the olefin-based monomer itself can be used as a medium. The solvent which can be used in the polymerization reaction may be selected from the group consisting of butane, isobutane, pentane, hexane, heptane, octane, nonane, decane, Aliphatic hydrocarbon solvents such as undecane, dodecane, cyclopentane, methylcyclopentane, and cyclohexane; Aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene and chlorobenzene; aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene, toluene, xylene and chlorobenzene; Halogenated aliphatic hydrocarbons such as dichloromethane, trichloromethane, chloroethane, dichloroethane, trichloroethane, and 1,2-dichloroethane, menstruum; Or a mixture thereof.

The first olefin polymer and the second olefin polymer are prepared in the presence of a catalyst comprising a main catalyst compound represented by the following formula (1).

[Chemical Formula 1]

In Formula 1, M is selected from the group consisting of the elements of Groups 3 to 10 on the periodic table, and is preferably selected from the group consisting of titanium (Ti), zirconium (Zr), and hafnium (Hf).

X is a halogen, an amine group, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl A silyl group, a silyl (C ₆ -C ₂₀ ) aryl group, a (C ₁ -C ₂₀ ) alkoxy group, a (C ₁ -C ₂₀ ) alkylsiloxy group and a (C ₆ -C ₂₀ ) aryloxy group , Methyl or chlorine.

n is an integer of 1 to 5, preferably an integer of 2.

Ar ¹ and Ar ² are the same or different and are each independently a ligand having a cyclopentadienyl skeleton wherein the ligand is selected from the group consisting of halogen, (C ₁ -C ₂₀ ) alkyl, (C ₃ -C ₂₀ ) (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl ( (C ₁ -C ₂₀ ) alkyl group, (C ₁ -C ₂₀ ) alkyl (C ₆ -C ₂₀ ) aryl group, (C ₆ -C ₂₀ ) arylsilyl group and silyl (C ₆ -C ₂₀ ) And when the substituent is plural, they may be the same as or different from each other, and the substituent may be bonded to another adjacent substituent to form a ring.

Such a catalyst may further comprise a cocatalyst compound which activates the main catalyst compound. The promoter compound may be an aluminoxane compound, an organoaluminum compound, a Bulky compound for activating the main catalyst compound, and the like. Specifically, the co-catalyst compound may be at least one selected from the group consisting of compounds represented by the following formulas (2) to (4).

(2)

In Formula 2, Y ¹ is a (C ₁ -C ₁₀ ) alkyl group, and q is an integer of 1 to 70.

The promoter compound represented by the general formula (2) is not particularly limited and may be selected from the group consisting of Methylaluminoxane, Ethylaluminoxane, Butylaluminoxane, Hexylaluminoxane, Octylaluminoxane, Decylaluminoxane, and the like.

(3)

In Formula 3, Y ² to Y ⁴ are the same or different, each independently represent a (C ₁ ~ C ₁₀₎ alkyl, (C ₁ ~ C ₁₀₎ is selected from the group consisting of alkoxy and halogen, but Y ² to at least one of Y ⁴ is an alkyl group (C ₁ ~ C _10).

The promoter compound represented by Formula 3 is not particularly limited and includes trimethylaluminum, triethylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminum, tri But are not limited to, tridecylaluminum, dimethylaluminum methoxide, diethylaluminum methoxide, dibutylaluminum methoxide, dimethylaluminum chloride, diethylaluminum chloride, ), Dibutylaluminum chloride, methylaluminum dimethoxide, ethylaluminum dimethoxide, butylaluminum dimethoxide, methylaluminum dichloride, and the like. aluminum dichloride, ethylaluminum dichloride, butylaluminum dichloride, and the like.

[Chemical Formula 4]

[CD]

In Formula 4, C is a hydrogen ion-binding cationic compound of Lewis base; And an oxidizing metal compound or a non-metal compound.

And D is an organic compound containing an element selected from the group consisting of elements of Groups 5 to 15 on the periodic table.

Specifically, the promoter compound represented by Formula 4 may be selected from the group consisting of triphenylcarbenium tetrakis (pentafluorophenyl) borate, trimethylammonium tetraphenylborate, triethylammonium tetra Triethylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tributylammonium tetraphenylborate, trimethylammonium tetrakis (pentafluorophenyl) borate, tri Triethylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, tripropylammonium tetrakis (pentafluorophenyl) borate, tributylammonium tetrakis Anilinium tetrakis (pentafluorophenyl) borate, anilinium tetraphenylborate, anilinium tetrakis (pentafluorophenyl) borate, N, N-dimethylaniline Pyridinium tetrakis (pentafluorophenyl) borate, Pyridinium tetraphenylborate, Pyridinium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, ferrocenium tetrakis (pentafluorophenyl) borate, silver tetraphenylborate, silver tetrakis (pentafluorophenyl) borate, silver tetrakis (pentafluorophenyl) , Tris (pentafluorophenyl) borane, tris (2,3,5,6-tetrafluorophenyl) borane, (2,3,4,5-tetrafluorophenyl) borane, tris (2,3,4,5-tetraphenylphenyl) borane, tris (3,4,5-trifluorophenyl) borane, and the like.

The amounts of the co-catalyst compounds represented by the formulas (2) to (6) are not particularly limited, and it is preferable that the co-catalyst compounds are mixed in the following ratios in view of catalytic activity and production cost.

The amount of the main catalyst compound represented by Formula 1 and the amount of the promoter compound represented by Formula 2 or 3 is determined by the ratio of the transition metal atom (M) contained in the main catalyst compound to the transition metal atom (Al) 10 to 100,000: 1, and preferably a molar ratio of 10 to 100: 1. The amount of the main catalyst compound represented by Formula 1 and the amount of the co-catalyst compound represented by Formula 4 is determined by the ratio of the transition metal atom (M) contained in the main catalyst compound: the central element (B) To 10: 1, preferably in a molar ratio of 1 to 3: 1.

The catalyst may be used when the main catalyst compound is supported on the carrier alone, or both the main catalyst compound and the cocatalyst compound are supported on the carrier.

The carrier is used in the production of a catalyst known in the art and can be used without limitation as long as it is a porous organic / inorganic compound having fine pores on its surface or inside. Specifically, the material used as the carrier may be an organic compound such as starch, cyclodextrin, or synthetic polymer; Silica (SiO _2), alumina (Al ₂ O _3), magnesium chloride (MgCl _2), calcium chloride (CaCl _2), beam Oak site, zeolites, magnesium oxide (MgO), zirconium oxide (ZrO _2), titanium oxide (TiO ₂ ), boron trioxide (B ₂ O ₃ ), calcium oxide (CaO), zinc oxide (ZnO), barium oxide (BaO), thorium oxide (ThO ₂ ), composites thereof (SiO ₂ -MgO, SiO ₂ -Al ₂ O ₃ , SiO ₂ -TiO ₂ , SiO ₂ -V ₂ O ₅ , SiO ₂ -Cr ₂ O ₃ , SiO ₂ -TiO ₂ -MgO). At this time, the support may include at least one member selected from the group consisting of silica (SiO ₂ ), silica-alumina (SiO ₂ -Al ₂ O ₃ ) and silica-magnesia (SiO ₂ -MgO) .

The method of supporting the main catalyst compound and the co-catalyst compound on the carrier is not particularly limited, but a method of directly supporting the main catalyst compound on a carrier from which moisture is removed; A method of pretreating the carrier with a promoter compound and then carrying the main catalyst compound; Supporting the main catalyst compound on the support, and then treating the support with a co-catalyst compound; A method of reacting the main catalyst compound with a cocatalyst compound and then adding and supporting a carrier. At this time, when two or more main / promoter compounds are supported, they may be carried on the carrier sequentially or all at once.

The temperature to be carried is not particularly limited, but is preferably -20 to 120 占 폚, more preferably 0 to 100 占 폚, in consideration of the efficiency of the supporting step.

The solvent usable in the above-mentioned carrying method may be a hydrocarbon solvent. Examples of the hydrocarbon solvent include, but are not limited to, Pentane, Hexane, Heptane, Octane, Nonane, Decane, Undecane, Dodecane, Aliphatic hydrocarbons; Aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene and toluene; and aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene and toluene; Halogenated aliphatic hydrocarbon solvents such as dichloromethane, trichloromethane, dichloroethane, and trichloroethane; Or a mixture thereof.

At this time, the amount of the catalyst to be used may be determined within a range in which the polymerization reaction of the monomers can sufficiently take place in the slurry, liquid phase, gas phase or mass process, and the like, and is not particularly limited. However, according to the present invention, the addition amount of the catalyst is in the range of 10 ^-8 to 1 mol / L, preferably 10 (mol / L) based on the concentration of the central metal (M) of the main catalyst compound per unit volume ^-7 to 10 ^{- 1} mol / L, more preferably from 10 ^-7 to ¹⁰ may be a ² mol / L. The conditions of the polymerization reaction are not particularly limited and can be determined in consideration of the efficiency of the polymerization reaction depending on the kind of the reaction to be applied and the kind of the reactor. The polymerization pressure is preferably 1 to 100 kg / cm 3, more preferably 5 to 60 kg / cm 3, and the polymerization temperature is 40 to 200 ° C., preferably 60 to 100 ° C.

On the other hand, the first olefin polymer and the second olefin polymer may be respectively prepared under respective reaction conditions in a single reactor, or continuously under each reaction condition in two continuous reactors.

When the first olefin polymer and the second olefin polymer are each produced in a single reactor, the temperature of the reactor in which each olefin polymer is produced may be the same or different.

When the first olefin polymer and the second olefin polymer are continuously produced in two continuous reactors, the temperature of the first reactor for producing the first olefin polymer is equal to or higher than the temperature of the second reactor for producing the second olefin polymer It should be low. At this time, the temperature for polymerizing the first olefin polymer is 40 to 150 ° C, and preferably 60 to 90 ° C. The temperature for polymerizing the second olefin polymer is 20 to 200 캜, preferably 70 to 100 캜.

Such a method of mixing the first olefin polymer and the second olefin polymer is a method using a kneading apparatus using the mechanical force of the screw rotating together with heat, thereby uniformly mixing the olefin polymers. In addition, the above mixing method can perform repeated kneading several times at least once, if necessary.

The first olefin polymer preferably has a weight average molecular weight (Mw) of 10,000 to 1,000,000 g / mol, preferably 30,000 to 300,000 g / mol, a z-average molecular weight Mz of 100,000 to 2,000,000 g / mol, 500,000 g / mol, and the comonomer content in the polymer is 0 to 2.0 wt%, preferably 0.01 to 0.5 wt%.

The second olefin polymer preferably has a weight average molecular weight (Mw) of 10,000 to 1,000,000 g / mol, preferably 100,000 to 600,000 g / mol, a z-average molecular weight Mz of 100,000 to 3,000,000 g / mol, 2,000,000 g / mol, and the comonomer content in the polymer is 0.01 to 10.0 wt%, preferably 0.1 to 3.0 wt%.

Preferably, the weight average molecular weight and the z-average molecular weight of the first olefin polymer are lower than those of the second olefin polymer and the comonomer content of the first olefin polymer is lower than that of the second olefin polymer.

Thus, when two kinds of polymers having different molecular weights and comonomer contents are mixed, a polyolefin having excellent pressure resistance and processability (moldability) can be produced.

Specifically, the molecular weight and the comonomer content of the olefin polymer affect the pressure resistance. When the molecular weight of the polymer increases, tie molecules are easily produced and the crystal structure develops, thereby improving the mechanical properties and the withstand voltage characteristics. In addition, when the content of comonomer in the high molecular weight chain of the polymer is increased, the entanglement of the polymer increases due to the increase of the SCB (Short Chain Branch), and the bonding of the crystalline structure is strengthened. Such an excellent tie molecule and a polymer having entanglement of the polymer improves the mechanical properties and the withstand pressure characteristics, but the molecular weight of the polymer excessively increases and the viscosity becomes high, resulting in deteriorated flow characteristics, and the moldability may be deteriorated. Therefore, in order to equally provide excellent mechanical properties and moldability, the final polyolefin must be prepared by mixing a polymer having a low viscosity and a polymer having a good moldability and a polymer having a good mechanical and pressure-resistance characteristics due to a high viscosity. Therefore, in one example of the present invention, the first olefin polymer having a low viscosity and the second olefin polymer having a high viscosity may be mixed at a certain ratio.

The mixing ratio of the first olefin polymer and the second olefin polymer is 1: 0.01 to 100: 1, and the weight ratio of the first olefin polymer to the second olefin polymer is preferably 1: 0.1 to 10.

The polyolefin is prepared by preparing a first olefin polymer and a second olefin polymer having different weight average molecular weights, z-average molecular weights, and comonomer contents in the presence of the catalyst containing the main catalyst compound represented by Formula 1 Followed by mixing to prepare a polyolefin. Due to this production method, the molecular weight and the content of the comonomer are increased, and polyolefin having excellent pressure resistance characteristics can be produced.

<Polyolefin>

The polyolefin is provided by the above production method according to an example of the present invention.

The polyolefin preferably has a weight average molecular weight (Mw) of 30,000 to 600,000 g / mol and 100,000 to 300,000 g / mol.

The polyolefin preferably has a z-average molecular weight (Mz) of 100,000 to 3,000,000 g / mol and a molecular weight of 400,000 to 2,000,000 g / mol.

The content of the comonomer in the polyolefin is preferably 0.01 to 3 wt%, more preferably 0.05 to 2 wt%.

Such a polyolefin is excellent in mechanical properties and processability due to its high molecular weight and comonomer content, and its environmental stress cracking resistance (ESCR) can be 1,000 hours or more.

EXAMPLES The present invention will now be described in detail with reference to the following examples, but it should be understood that the present invention is not construed as being limited thereto.

[ Preparation Example ] Preparation of Catalyst

The synthesis reaction for preparing the catalyst was carried out in an inert atmosphere such as nitrogen or argon, and the standard Schlenk technique and the glove box technique were used.

Toluene and n-hexane used in the preparation of the catalyst were purchased from Sigma-Aldrich in anhydrous grade and used after passing through an activated molecular sieve (Molecular Sieve, 4A) or an activated alumina layer. Methylaluminoxane (MAO) was purchased from Albemarle and a 10% toluene solution (HS-MAO-10%) in which methylaluminoxane was dissolved was used. Silica and bis (1-butyl-3-methylcyclopentadienyl) zirconium dichloride were purchased from Grace Davison and s-PCI, respectively, for further processing (Tablets).

First, 1.0 g of silica was put in a round bottom flask (100 ml) in a glove box, and then the flask was taken out of the glove box. To the flask was added 10 ml of toluene to prepare silica in a slurry state. 6.67 ml of methyl aluminum was slowly added to the prepared slurry silica, and the mixture was stirred at 70 ° C for 1 hour.

100 ml of bis (1-butyl-3-methylcyclopentadienyl) zirconium dichloride was charged into a new round bottom flask (100 ml) in a glove box, and the flask was taken out of the glove box. 10 ml of toluene was added to the flask to dissolve the solution, which was slowly added to the slurry containing the silica and MAO. Thereafter, the mixture was stirred at 50 DEG C for 1 hour, cooled to room temperature, and the toluene supernatant was separated and removed. Thereafter, the reaction product was washed with toluene and n-hexane, and vacuum dried to prepare a supported catalyst in the form of Free Flowing Powder.

[ Example  1] Production of polyethylene

&Lt; Step 1 > Preparation of first olefin polymer

After the supported catalyst prepared in the preparation example was charged into the reactor, 33 kg / hr of ethylene was fed, and the reaction pressure was 42 kg / cm ² and the reaction temperature was maintained at 70 ° C to prepare a first olefin polymer.

&Lt; Step 2 > Preparation of second olefin polymer

A second olefin polymer was prepared by feeding the supported catalyst prepared in the above preparation example into the reactor and then feeding 33 kg / hr of 1-hexene and ethylene at a reaction pressure of 42 kg / cm ² and a reaction temperature of 85 ° C.

<Step 3> Production of polyethylene

The first olefin polymer prepared in <Step 1> and the second olefin polymer prepared in <Step 2> were blended at a weight ratio of 1: 1 to prepare polyethylene.

[ Comparative Example  1] Production of polyethylene

A polyethylene (trade name: Lotte Chemical Co., Ltd., 5200B) mixed with a first olefin polymer and a second olefin polymer produced using a Ziegler-Natta catalyst was used.

[ Experimental Example  1] Measurement of physical properties

The physical properties of the polyethylene of Example 1 and Comparative Example 1 were measured, and the results are shown in Table 1 below.

At this time, the weight average molecular weight and the z-average molecular weight were analyzed by gel permeation chromatography-FT-IR (GPC-FTIR).

Melt index was analyzed by Melt Indexer.

Comonomer content was analyzed by 13C-NMR.

The environmental stress cracking resistance was analyzed by ASTM D1693.

Example 1 Comparative Example 1 The first olefin polymer The second olefin polymer Polyethylene Polyethylene density
(g / cm3) 0.960 0.932 0.950 0.963 Weight average molecular weight
(× 10 ⁴ ) 9 41 25 29 z-average molecular weight
(× 10 ⁴ ) 15 66 64 132 Melt Index
(MI, g / 10 min) 22 0.01 0.22 0.30 Comonomer content
(wt%) 0 2.08 0.61 0.23 Environmental stress cracking property
(hr) - - > 1000 20

As shown in Table 1, it was confirmed that the polyolefin prepared in Example 1 had a high molecular weight and a high comonomer content and was superior in environmental stress cracking resistance to the polyolefin of Comparative Example 1.

[ Experimental Example  2] Analysis of molecular weight distribution

The molecular weight distribution and comonomer distribution of the polyethylene of Example 1 and Comparative Example 1 were measured, and the results are shown in FIGS. 1 and 2. FIG.

At this time, the molecular weight distribution was measured by gel permeation chromatography (GPC) and the comonomer distribution was measured by gel permeation chromatography-IR (GPC-IR).

Referring to FIG. 1, it was confirmed that the polyethylene produced in Example 1 had a higher molecular weight than the polyethylene of Comparative Example 1.

Referring to FIG. 2, it was confirmed that the polyethylene produced in Example 1 had an excellent comonomer distribution as compared with the polyethylene of Comparative Example 1.

Claims (12)

(a) polymerizing a first olefin-based monomer to prepare a first olefin polymer; And
(b) polymerizing the second olefin monomer to prepare a second olefin polymer, and mixing the first olefin polymer and the second olefin polymer
/ RTI &gt;
Wherein the first olefin polymer has a weight average molecular weight (Mw) of 30,000 to 300,000 g / mol, a z-average molecular weight (Mz) of 100,000 to 500,000 g / mol, a comonomer content of 0 to 2.0 wt%
Wherein the second olefin polymer has a weight average molecular weight (Mw) of 100,000 to 600,000 g / mol, a z-average molecular weight (Mz) of 400,000 to 2,000,000 g / mol, a comonomer content of 0.01 to 10 wt%
The second olefin polymer has a weight average molecular weight, a z-average molecular weight, and a comonomer content higher than that of the first olefin polymer,
Wherein the first olefin polymer and the second olefin polymer are prepared in the presence of a catalyst comprising a main catalyst compound represented by the following formula (1).
[Chemical Formula 1]

(In the formula 1,
M is selected from the group consisting of Group 3 to Group 10 elements on the periodic table,
X is a halogen, an amine group, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl A silyl group, a silyl (C ₆ -C ₂₀ ) aryl group, a (C ₁ -C ₂₀ ) alkoxy group, a (C ₁ -C ₂₀ ) alkylsiloxy group and a (C ₆ -C ₂₀ ) aryloxy group ,
n is an integer of 1 to 5,
Ar ¹ and Ar ² are the same or different and are each independently a ligand having a cyclopentadienyl skeleton wherein the ligand is selected from the group consisting of halogen, (C ₁ -C ₂₀ ) alkyl, (C ₃ -C ₂₀ ) (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl ( (C ₁ -C ₂₀ ) alkyl group, (C ₁ -C ₂₀ ) alkyl (C ₆ -C ₂₀ ) aryl group, (C ₆ -C ₂₀ ) arylsilyl group and silyl (C ₆ -C ₂₀ ) And when the substituent is plural, they may be the same or different from each other, and the substituent may be combined with adjacent adjacent substituents to form a ring. The method according to claim 1,
Wherein the first olefin polymer and the second olefin polymer are each prepared in a separate reactor. The method according to claim 1,
In the step (b), the first olefin polymer produced in the step (a) is introduced before the polymerization of the second olefin-based monomer. The method according to claim 1,
Wherein the first olefin monomer and a second olefin monomer is (C ₂ ~ C ₂₀₎ α- olefin, (C ₄ ~ C ₂₀₎ diolefin, (C ₃ ~ C ₂₀₎ cycloolefin, (C ₄ ~ C ₂₀ ) A process for producing a polyolefin which is at least one selected from the group consisting of cyclodiolefin and styrene. The method according to claim 1,
Wherein the first olefin polymer and the second olefin polymer are produced under the conditions of a pressure of 1 to 100 kg / cm 3 and a temperature of 20 to 200 캜. The method of claim 3,
The first olefin polymer is prepared at a temperature of 40 to 150 DEG C,
Wherein the second olefin polymer is produced at a temperature of 20 to 200 占 폚. delete The method according to claim 1,
Wherein the mixing ratio of the first olefin polymer to the second olefin polymer is a weight ratio of the first olefin polymer: the second olefin polymer = 1: 0.1 to 10. The method according to claim 1,
Wherein the catalyst further comprises at least one cocatalyst compound selected from the group consisting of compounds represented by the following Chemical Formulas (2) to (4).
(2)

(In the formula (2)
Y ¹ is a (C ₁ -C ₁₀ ) alkyl group,
and q is an integer of 1 to 70.)
(3)

(3)
Y ² to Y ⁴ are the same or different, and each independently represents a (C ₁ ~ C ₁₀₎ alkyl, (C ₁ ~ C ₁₀₎ alkoxy group and is selected from the group consisting of halogen, just Y ² to Y ⁴ in at least One is a (C ₁ -C ₁₀ ) alkyl group.)
[Chemical Formula 4]
[CD]
(In the formula 4,
C is a hydrogen ion-bound cationic compound of Lewis base; And an oxidizing metal compound or a non-metal compound,
And D is an organic compound containing an element selected from the group consisting of elements of Groups 5 to 15 on the periodic table.) The method according to claim 1,
The catalyst ₂ SiO, Al ₂ O _3, MgO, ₂ MgCl, CaCl _2, ZrO _{2, 2} TiO, ₃ B ₂ O, CaO, ZnO, BaO, ThO _2, SiO ₂ -Al ₂ O _3, SiO ₂ - MgO, SiO ₂ -TiO ₂ , SiO ₂ -V ₂ O ₅ , SiO ₂ -Cr ₂ O ₃ , SiO ₂ -TiO ₂ -MgO, borosite, zeolite, starch and cyclodextrin By weight of the polyolefin. A polyolefin produced by the process of any one of claims 1 to 6 and 8 to 10. 12. The method of claim 11,
A polyolefin having a weight average molecular weight (Mw) of 100,000 to 300,000 g / mol, a z-average molecular weight (Mz) of 400,000 to 2,000,000 g / mol and a comonomer content of 0.01 to 3 wt%.

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