KR102761660B1 - Supported hybrid metallocene catalyst, method for preparing polyethylene using the same, and polyethylene copolymer - Google Patents

Abstract

The present invention relates to a hybrid supported metallocene catalyst, a method for producing a polyethylene copolymer using the hybrid supported metallocene catalyst, and a polyethylene copolymer having high strength and ESCR properties. The present invention provides a hybrid supported metallocene catalyst for polyethylene polymerization in which a metallocene catalyst compound is supported on a support, wherein two kinds of metallocene catalyst compounds, a first metallocene catalyst compound represented by chemical formula 1 and a second metallocene catalyst compound represented by chemical formula 2, are co-supported:
[Chemical Formula 1]

[Chemical formula 2]

Description

SUPPORTED HYBRID METALLOCENE CATALYST, METHOD FOR PREPARING POLYETHYLENE USING THE SAME, AND POLYETHYLENE COPOLYMER

The present invention relates to a hybrid supported metallocene catalyst, a method for producing a polyethylene copolymer using the hybrid supported metallocene catalyst, and a polyethylene copolymer having high strength and ESCR properties.

Polyolefins, especially polyethylene, produced using a metallocene catalyst system have a narrow molecular weight distribution and therefore have very poor processability. Accordingly, various methods have been proposed to improve processability.

Among these methods, a method of using two or more reactors and making the conditions of each reactor different, producing polyolefins having different properties in each reactor and mixing them in parallel to broaden the molecular weight distribution, and a method of producing polyolefins by mixing catalyst compounds of different structures and mixing the obtained polyolefins at an appropriate ratio to control the molecular weight distribution of the final polyolefin product are suggested.

Among these, the second method utilizes the characteristic that the structure of the metallocene catalyst compound is divided into several types and that the reactivity differs depending on the structure, and mainly manufactures polyethylene by mixing metallocene catalysts of different structures. At this time, the metallocene catalyst not only shows a difference in activity depending on the structure, but also shows a difference in the molecular weight/hydrogen reactivity and comonomer incorporation rate of the produced polyethylene copolymer, so fine control is also necessary for such process conditions.

In particular, when the molecular weight and hydrogen reactivity of the polyethylene copolymer being produced are excessively different, the molecular weight distribution becomes very wide, which results in inhibiting the unique uniform physical properties of the polyethylene copolymer produced using the basic metallocene catalyst system, and also, when the operating conditions are not given appropriately, the occurrence rate of fish-eye, etc. increases, which causes problems such as lowering the product quality.

In addition, when the molecular weight distribution is broadened, a product is obtained in which the peaks of the low molecular weight portion and the high molecular weight portion are clearly distinguished in the bimodal distribution in GPC molecular weight distribution analysis. In this case, since the amount of low molecular weight produced also increases, the physical properties become weak, and there is a high possibility that the product will be defective.

Nevertheless, since it has the advantage of lower molecular content than products using a Ziegler-Natta catalyst and can control the difference in reactivity of comonomers, polyolefins are produced using a metallocene catalyst system, and in particular, polyolefins are produced using a metallocene catalyst system in the manufacture of pipe products used as construction materials requiring excellent long-term durability.

Polyolefin manufacturing technologies using such metallocene catalysts include US Patent Publication No. 2007-0043176 (Title: Metallocene polymerization catalysts and process for producing bimodal polymers in a single reactor), US Patent Publication No. 2007-0197374 (Title: Dual metallocene catalysts for polymerization of bimodal polymers), US Patent No. 7,141,632 (Title: Mixed metallocene catalyst systems containing a poor comonomer incorporator and a good comonomer incorporator), and Korean Patent No. 0646249 (Title: Polyethylene for water supply pipes with excellent processability and pressure resistance using mixed supported metallocene catalyst and its manufacturing method).

Meanwhile, Korean Patent Publication No. 2010-0086863 discloses a technology for manufacturing polyethylene with a very wide molecular weight distribution using two types of catalysts, which uses heterogeneous catalysts to increase the content of high molecular weight in order to improve the pressure-resistant characteristics of the product pipe. However, the proportion of relatively low molecular weight also increases, and the difference in molecular weight becomes too large, so that the melt flow of the molten resin itself is not uniform during molding, making molding difficult.

Furthermore, many literatures have disclosed the composition of products having two peaks in the GPC curve and a very broad molecular weight distribution in the production of polyethylene polymers with a bimodal composition using a metallocene catalyst. However, when the molecular weight distribution is broad, the low molecular weight peak is composed of lower molecular weights, and this increase in the content of low molecular weight acts as a factor that interferes with providing proper formability in high-speed molding, and can cause problems of reduced formability such as die drool.

In order to solve the problems in the above conventional technology, it is required to be able to control the molecular weight distribution to a level that can maintain the formability of the product while not making the molecular weight distribution too broad.

In particular, for pipe products that must withstand high water pressure, high crystallinity is required, and in order to increase the crystallinity of such products, it is important to increase the density. In addition, in order to secure the stability of product use for a long time, it is necessary to increase long-term durability, and for this long-term durability, it is required to increase tie-molecules.

The above tie-molecule has a high distribution of short chain branches (SCB) in the long high molecular weight chains, which serve to entangle crystalline regions across multiple crystalline regions and provide resistance to long-term stress. In order to increase the tie-molecule, it is desirable to concentrate SCB in the high molecular weight portion, which means that the high molecular weight portion has low-density characteristics.

That is, in order to be used as a pipe product subject to high water pressure, it is desirable to have high crystallinity and low density characteristics, but these high crystallinity and low density characteristics are conflicting characteristics, and in order to have both characteristics, it is required to manufacture the polymer composition in a balanced manner.

Accordingly, the present invention aims to provide a hybrid supported metallocene catalyst having an appropriate molecular weight distribution with a small difference between low molecular weight and high molecular weight and capable of significantly increasing the difference in the content of comonomer. In particular, the present invention aims to provide a hybrid supported metallocene catalyst suitable for producing PERT (Polyethylene of Raised Temperature), which is suitable for producing pipe products.

Furthermore, the present invention aims to provide a polyethylene copolymer and a method for producing the same, which has an appropriate molecular weight distribution with a small difference between low molecular weight and high molecular weight by using the hybrid supported metallocene catalyst, so that the copolymer has excellent formability during pipe forming, has excellent crystallinity, so that a product having excellent pressure resistance characteristics can be obtained when manufacturing a pipe product, and at the same time has low density characteristics, so that the long-term durability of the pipe product can be improved.

That is, the present invention aims to provide a method for producing a polyethylene copolymer having high strength and high ESCR using the hybrid supported metallocene catalyst, and a polyethylene copolymer obtained thereby.

The present invention provides, as an embodiment, a hybrid supported metallocene catalyst in which a metallocene catalyst compound is supported on a carrier, wherein the hybrid supported metallocene catalyst is a hybrid supported metallocene catalyst in which two kinds of metallocene catalyst compounds, a first metallocene catalyst compound represented by chemical formula 1 and a second metallocene catalyst compound represented by chemical formula 2, are supported on a carrier.

[Chemical Formula 1]

(In the above chemical formula 1, M ¹ is an element of groups 3 to 10 of the periodic table, and X ¹ is a halogen group, an amine group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a (C ₁ to C ₂₀ ) silylalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl(C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl(C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group, a (C ₆ to C ₂₀ ) silylaryl group, a (C ₁ to C ₂₀ ) alkoxy group, a (C ₁ to C ₂₀ ) alkylsiloxy group, and a (C ₆ to C ₂₀ ) is selected from the group consisting of aryloxy groups, k is determined by the oxidation number of the central metal and is an integer from 1 to 5, and Ind ¹ and Ind ² are ligands having an indenyl skeleton, which are the same or different and each independently);

[Chemical formula 2]

(In the above chemical formula 2, M ² is an element of groups 3 to 10 of the periodic table, and X ² is a halogen group, an amine group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a (C ₁ to C ₂₀ ) silylalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl(C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl(C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group, a (C ₆ to C ₂₀ ) silylaryl group, a (C ₁ to C ₂₀ ) alkoxy group, a (C ₁ to C ₂₀ ) alkylsiloxy group, and a (C ₆ to C ₂₀ ) is selected from the group consisting of aryloxy groups, n is determined by the oxidation number of the central metal (M ² ) and is an integer from 1 to 5, Z is a component that does not directly coordinate to the transition metal M ² but connects the ligands Ind ³ and Ind ⁴ and is selected from the group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N) or phosphorus (P), and R is hydrogen or a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C _{1 to C 20 ) alkylsilyl group, a (C 1} to C ₂₀ ) silylalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C 20 ) alkyl (C 6 to C 20 ) aryl group, a (C 6 to C _{20 ) aryl (C 1 to C 20} ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ ~C ₂₀ )arylsilyl group or (C ₁ ~C ₂₀ )silylaryl group, m is determined depending on Z and is an integer of 1 or 2, and Ind ³ and Ind ⁴ are each independently a ligand having an indenyl skeleton.

Ind ¹ and above Ind ² may be independently represented by chemical formula 1-1.

[Chemical Formula 1-1]

(In the above chemical formula 1-1, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ has a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a (C ₁ to C ₂₀ ) silylalkyl group, a (C ₁ to C ₂₀ ) haloalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl(C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl(C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group or a (C ₆ to C ₂₀ ) silylaryl group, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ may be combined with two or more to form a ring.)

The second metallocene catalyst compound represented by the above chemical formula 2 may be represented by chemical formula 2-1.

[Chemical Formula 2-1]

(In the above chemical formula 2-1, M ² , X ² , n, Z, R and m are as defined in chemical formula 2, and R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ are each independently hydrogen, a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a halo (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group or a silyl (C ₆ ~C ₂₀ )aryl group, R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ may be combined with each other in groups of two or more to form a ring, and R ¹⁰ is a (C ₆ ~C ₂₀ )aryl group.

In the above chemical formula 2-1, R ¹⁰ may be an aryl group represented by chemical formula 3.

[Chemical Formula 3]

(In the above chemical formula 3, R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently selected from the group consisting of hydrogen, a halogen group, a (C ₁ -C ₂₀ ) alkyl group, a (C ₃ -C ₂₀ ) cycloalkyl group, a (C ₁ -C ₂₀ ) alkylsilyl group, _{a silyl (C 1 -C 20 ) alkyl group, a halo (C 1 -C 20 ) alkyl group, a (C 6 -C 20 ) aryl group ,} a (C ₆ -C ₂₀ ) aryl (C ₁ -C ₂₀ ) alkyl group, a (C ₁ -C ₂₀ ) alkyl (C ₆ -C ₂₀ ) aryl group, a (C 6 -C ₂₀ ) arylsilyl group and a silyl (C ₆ -C ₂₀ ) aryl group, and R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ may be combined with two or more to form a ring.)

It is preferable that the first metallocene catalyst compound and the second metallocene catalyst compound are supported in a hybrid manner at a molar ratio of 10:1 to 1:10.

The hybrid supported metallocene catalyst for producing the above polyethylene copolymer may further include at least one cocatalyst selected from the group consisting of chemical formulae 4 to 6.

[Chemical Formula 4]

-[Al(R ¹⁷ )-O] _n -

(In chemical formula 4, Al is aluminum,

O is oxygen,

Y ¹ is halogen; or a (C ₁ -C ₂₀ )hydrocarbyl group substituted or unsubstituted with halogen,

n is an integer greater than or equal to 2);

[Chemical Formula 5]

Q(Y ² ) ₃

(In chemical formula 5, Q is aluminum or boron,

Y ² is independently a halogen or a (C ₁ -C ₂₀ ) hydrocarbyl group unsubstituted or substituted with a halogen);

[Chemical formula 6]

[W] ⁺ [Z ^a (A) ₄ ] ^-

(In chemical formula 6, W is a cationic Lewis acid or a cationic Lewis acid to which a hydrogen atom is bonded,

Z ^a is a group 13 element;

A is a (C ₆ -C ₂₀ )aryl group substituted with one or more substituents each independently selected from the group consisting of a halogen, a (C ₁ -C ₂₀ )hydrocarbyl group, an alkoxy group, and a phenoxy group; A (C ₁ -C ₂₀ )alkyl group substituted with one or more substituents selected from the group consisting of a halogen, a (C ₁ -C ₂₀ )hydrocarbyl group, an alkoxy group, and a phenoxy group.

In another aspect, the present invention provides a method for producing a polyethylene copolymer by reacting one or more olefin monomers in the presence of a hybrid supported metallocene catalyst as described above.

The above olefin monomer can be selected from the group consisting of α-olefins of (C ₂ to C ₂₀ ), diolefins of (C ₄ to C ₂₀ ), cycloolefins of (C ₃ to C ₂₀ ), cyclodiolefins of (C ₃ to C ₂₀ ), styrene and styrene derivatives.

In another aspect, the present invention provides a polyethylene copolymer polymerized in the presence of a hybrid supported metallocene catalyst as described above, having a weight average molecular weight (Mw) of 100,000 to 300,000 and a molecular weight distribution (Mw/Mn) of 3.0 to 5.0.

The above polyethylene copolymer has a bimodal distribution of a low molecular weight component peak and a high molecular weight component peak as a result of GPC molecular weight distribution analysis, and the high molecular weight component peak accounts for 10 to 40 wt%.

The above polyethylene copolymer may have a number of SCBs at the peak of a high molecular weight component that is at least twice the number of SCBs at the peak of a low molecular weight component.

Furthermore, the polyethylene copolymer may have a low molecular weight content of less than 1 wt%.

When a polyethylene copolymer is produced using the hybrid supported metallocene catalyst provided in the present invention, a polyethylene copolymer having a bimodal composition and an appropriate molecular weight distribution in which the difference between low molecular weight and high molecular weight is not large can be produced.

Furthermore, when forming a pipe using the polyethylene copolymer obtained thereby, the difference in the content of the comonomer can be significantly reduced, so that the formability is excellent, and since the crystallinity is excellent, a product having excellent pressure resistance characteristics can be obtained when manufacturing a pipe product, and at the same time, it has low density characteristics, so that the long-term durability of the pipe product can be improved.

The present invention aims to provide a hybrid supported metallocene catalyst in which two kinds of metallocene catalyst compounds are supported on a carrier as main catalysts.

As the main catalyst of the hybrid supported metallocene catalyst of the present invention, a first metallocene catalyst compound represented by chemical formula 1 and a second metallocene catalyst compound represented by chemical formula 2 are supported on a carrier.

[Chemical Formula 1]

In the above chemical formula 1,

M ¹ is an element in groups 3 to 10 of the periodic table,

X ¹ is selected from the group consisting of a halogen group, an amine group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group, a silyl (C ₆ to C ₂₀ ) aryl group, a (C ₁ to C ₂₀ ) alkoxy group, a (C ₁ to C ₂₀ ) alkylsiloxy group, and a (C ₆ to C ₂₀ ) aryloxy group,

k is determined by the oxidation number of the central metal and is an integer from 1 to 5,

Ind ¹ and Ind ² is a ligand having an indenyl skeleton, which is the same or different from each other and is independently selected from the group consisting of Ind ¹ and Ind ² can be a substituent independently represented by the following chemical formula 1-1.

[Chemical Formula 1-1]

In the chemical formula 1-1, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ has a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a halo (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group or a silyl (C ₆ to C ₂₀ ) aryl group, and R ¹ , R ² , R Two or more of ^{R 3} , R ⁴ , R ⁵ , R ⁶ and R ⁷ may combine with each other to form a ring.

[Chemical formula 2]

In the above chemical formula 2,

M ² is an element of groups 3 to 10 of the periodic table, preferably an element of group 4 of the periodic table,

X ² is selected from the group consisting of a halogen group, an amine group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group, a silyl (C ₆ to C ₂₀ ) aryl group, a (C ₁ to C ₂₀ ) alkoxy group, a (C ₁ to C ₂₀ ) alkylsiloxy group, and a (C ₆ to C ₂₀ ) aryloxy group,

n is determined by the oxidation number of the central metal and is an integer from 1 to 5.

Z is a component that does not directly coordinate to the transition metal M ² but connects the ligands Ind ³ and Ind ⁴ , and is selected from the group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N), or phosphorus (P).

R is selected from the group consisting of hydrogen or a (C ₁ ~C ₂₀ ) alkyl group, a (C ₃ ~C ₂₀ ) cycloalkyl group, a (C ₁ ~C ₂₀ ) alkylsilyl group, a silyl (C ₁ ~C ₂₀ ) alkyl group, a (C ₆ ~C ₂₀ ) aryl group, a (C ₆ ~C ₂₀ ) aryl (C ₁ ~C ₂₀ ) alkyl group, a (C ₁ ~C ₂₀ ) alkyl (C ₆ ~C ₂₀ ) aryl group, a (C ₆ ~C ₂₀ ) arylsilyl group or a silyl (C ₁ ~C ₂₀ ) aryl group,

m is determined by Z and is an integer of 1 or 2,

Ind ³ and Ind ⁴ can independently be ligands having an indenyl skeleton.

The compound represented by the above chemical formula 2 may more preferably be a compound represented by chemical formula 2-1.

[Chemical Formula 2-1]

In the above chemical formula 2-1,

M ² , X ² , n, Z, R and m are as defined in chemical formula 2,

R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ are each independently selected from the group consisting of hydrogen, a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a halo (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group or a silyl (C ₆ to C ₂₀ ) aryl group, and R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ can be combined with two or more to form a ring,

R ¹⁰ may be a (C ₆ ~C ₂₀ ) aryl group, and more preferably, the aryl group may be a substituent represented by chemical formula 3.

[Chemical Formula 3]

In the above chemical formula 3, R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently selected from the group consisting of hydrogen, a halogen group, a (C ₁ -C ₂₀ ) alkyl group, a (C ₃ -C ₂₀ ) cycloalkyl group, a (C ₁ -C ₂₀ ) alkylsilyl group, _{a silyl (C 1 -C 20 ) alkyl group, a halo (C 1 -C 20 ) alkyl group, a (C 6 -C 20 ) aryl group ,} a (C ₆ -C ₂₀ ) aryl (C ₁ -C ₂₀ ) alkyl group, a (C ₁ -C ₂₀ ) alkyl (C 6 -C ₂₀ ) aryl group, a (C ₆ -C ₂₀ ) arylsilyl group and a silyl (C ₆ -C ₂₀ ) aryl group, and R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ may be combined in groups of two or more to form a ring.

The first metallocene catalyst compound and the second metallocene catalyst compound are not limited thereto, but the first metallocene catalyst compound:the second metallocene catalyst compound may be supported at a molar ratio of the central metal of 30:1 to 1:30. When the molar ratio is less than 30:1 and more than 1:30, it is difficult to produce a product having a uniform composition, and the deviation in the physical properties of the product produced may increase. It is more preferable that the molar ratio of the first metallocene catalyst compound:the second metallocene catalyst compound be supported at a molar ratio of 10:1 to 1:10.

The metallocene catalyst of the present invention may include a mixture of a main catalyst compound of the first metallocene catalyst compound and the second metallocene catalyst compound as described above, together with a cocatalyst compound, and the cocatalyst compound may be at least one of compounds having a structure represented by the following chemical formulas 4 to 6.

The above-mentioned hybrid supported metallocene catalyst includes a cocatalyst. The cocatalyst activates the metallocene catalyst compound, and may be an aluminoxane compound, an organo-aluminum compound, or a bulky compound that activates the catalyst compound. Specifically, the cocatalyst compound may be selected from the group consisting of compounds represented by the following chemical formulas 4 to 6.

[Chemical Formula 4]

-[Al(Y ¹ )-O] _n -

Al is aluminum,

O is oxygen,

Y ¹ is a halogen; or a (C ₁ -C ₂₀ )hydrocarbyl group substituted or unsubstituted with a halogen, for example, a (C ₁ ~C ₁₀ )alkyl group,

n is an integer greater than or equal to 2.

[Chemical Formula 5]

Q(Y ² ) ₃

In the above chemical formula 5,

Q is aluminum or boron,

Y ² is independently a halogen or a (C ₁ -C ₂₀ ) hydrocarbyl group unsubstituted or substituted with a halogen, for example, a (C ₁ -C ₂₀ )alkyl group.

[Chemical formula 6]

[W] ⁺ [Z ^a (A) ₄ ] ^-

In chemical formula 6, W is a cationic Lewis acid or a cationic Lewis acid to which a hydrogen atom is bonded,

Z ^a is a group 13 element;

A is a (C ₆ -C ₂₀ )aryl group substituted with one or more substituents each independently selected from the group consisting of a halogen, a (C ₁ -C ₂₀ )hydrocarbyl group, an alkoxy group, and a phenoxy group; a (C ₁ -C ₂₀ )alkyl group substituted with one or more substituents selected from the group consisting of a halogen, a (C ₁ -C ₂₀ )hydrocarbyl group, an alkoxy group, and a phenoxy group.

The above cocatalyst compound is included in the catalyst together with the first metallocene catalyst compound represented by the chemical formula 1 and the second metallocene catalyst compound represented by the chemical formula 2, and serves to activate the metallocene catalyst compound. Specifically, in order for the metallocene catalyst compound to become an active catalyst component used in olefin polymerization, a compound including a unit represented by the chemical formula 2 that can act as a counterion with a weak binding force, i.e. anion, by extracting a ligand in the metallocene compound to cationize the central metal (M ¹ or M ² ), a compound represented by the chemical formula 3, and a compound represented by the chemical formula 4 act together as cocatalysts.

The 'unit' represented by the chemical formula 4 above is a structure in which n structures within [ ] are connected within the compound, and if it includes a unit represented by the chemical formula 2, other structures within the compound are not particularly limited, and it can be a cluster-type, for example, a spherical compound in which the repeating units of the chemical formula 2 are connected to each other.

In order for the cocatalyst compound to exhibit a better activation effect, the compound represented by the above chemical formula 4 is not particularly limited as long as it is an alkylaluminoxane, but preferred examples include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc., and a particularly preferred compound is methylaluminoxane.

In addition, the compound represented by the above chemical formula 5 is not particularly limited as an alkyl metal compound, and non-limiting examples thereof include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri-s-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylaluminum methoxide, dimethylaluminum ethoxide, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, and the like. Considering the activity of the above metallocene compound, one or more selected from the group consisting of trimethylaluminum, triethylaluminum and triisobutylaluminum can be preferably used.

When considering the activity of the metallocene compound, the compound represented by the chemical formula 6 is preferably used in which, when [W] ⁺ is a cationic Lewis acid bonded with a hydrogen atom, it is a dimethylanilinium cation, and when [W] ⁺ is a cationic Lewis acid, it is [(C ₆ H ₅ ) ₃ C] ⁺ , and [Z ^a (A) ₄ ] ^- is [B(C ₆ F ₅ ) ₄ ] ^- .

The compound represented by the chemical formula 6 is not particularly limited, but non-limiting examples in which [W] ⁺ is a cationic Lewis acid bonded with a hydrogen atom include triphenylcarbenium borate, trimethylammonium tetraphenylborate, methyldioctadecylammonium tetraphenylborate, triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, methyltetradecyclooctadecylammonium tetraphenylborate, N,N-dimethylanilium tetraphenylborate, N,N-diethylanilium tetraphenylborate, N,N-dimethyl(2,4,6-trimethylanilium)tetraphenylborate, trimethylammonium tetrakis(pentafluorophenyl)borate, methylditetradecylammonium tetrakis(pentaphenyl)borate, and methyldioctadecylammonium. Tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, tri(sec-butyl)ammonium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilium tetrakis(pentafluorophenyl)borate, N,N-diethylanilium tetrakis(pentafluorophenyl)borate, N,N-dimethyl(2,4,6-trimethylanilium)tetrakis(pentafluorophenyl)borate, trimethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, triethylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, tripropylammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, Tri(n-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, dimethyl(t-butyl)ammonium tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethylanilium tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-diethylanilium tetrakis(2,3,4,6-tetrafluorophenyl)borate, N,N-dimethyl-(2,4,6-trimethylanilium)tetrakis-(2,3,4,6-tetrafluorophenyl)borate, dioctadecylammonium tetrakis(pentafluorophenyl)borate, ditetradecylammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetrakis(pentafluorophenyl)borate, triphenylphosphonium tetrakis(pentafluorophenyl)borate, Examples thereof include methyldioctadecylphosphonium tetrakis(pentafluorophenyl)borate, tri(2,6-dimethylphenyl)phosphonium tetrakis(pentafluorophenyl)borate, methyldi(octadecyl)ammonium tetrakis(pentafluorophenyl)borate, methyldi(tetradecyl)-ammonium tetrakis(pentafluorophenyl)borate, and triethyl tetrakis(pentafluorophenyl)borate.

In addition, the metallocene catalyst of the present invention includes a carrier (C) supporting a main catalyst (A) and a cocatalyst compound (B) in which the metallocene catalyst compound is mixed.

The carrier is a porous material having a large surface area and fine pores on the surface or inside, and if it is commonly used, it can be used as the carrier of the present invention, and for example, it can be used in the form of silica (SiO ₂ ), alumina (Al ₂ O ₃ ), magnesium chloride (MgCl ₂ ), or a mixture thereof, and a synthetic polymer, etc. can be used. Furthermore, the carrier may also contain a small amount of carbonate, sulfate, or nitrate.

The method for supporting the main catalyst and co-catalyst compound on the carrier as described above is not particularly limited, and a method of directly supporting the main catalyst on a dehydrated carrier, a method of pretreating the carrier with the co-catalyst compound and then supporting the main catalyst, a method of supporting the main catalyst on the carrier and then post-treating it with the co-catalyst compound, a method of reacting the transition metal compound and the co-catalyst compound, and then adding the carrier to cause a reaction may be applied.

In addition, solvents applicable to the above-described supporting method include, for example, aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, nonane, decane, undecane, and dodecane; aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene, and toluene; and halogenated aliphatic hydrocarbon solvents such as dichloromethane, trichloromethane, dichloroethane, and trichloroethane. These solvents may be used alone or in combination of two or more.

In addition, the temperature at which the main catalyst and co-catalyst compounds are supported on the carrier is not particularly limited, but it is more preferable to perform the process under temperature conditions of -20°C to 120°C, preferably 0°C to 100°C, as this can improve the efficiency of the support process.

When the above-mentioned co-catalyst compound is a compound having a structure of Chemical Formula 4 or Chemical Formula 5, the usage ratio (equivalent ratio) of the main catalyst (A) and the co-catalyst compound (B) may be included in a molar ratio of 100:1 to 1:1,000. If the equivalent ratio of the main catalyst and the co-catalyst compound is low, such as 100:1 or less, the polymerization characteristics of the main catalyst compound cannot be expressed, and if it is excessive, such as 1:1000 or more, it is difficult to properly support the carrier, which may cause the characteristics of the supported catalyst to be lost and may cause a leaching problem.

Meanwhile, when the cocatalyst compound is a compound having a structure of chemical formula 6, the usage ratio (equivalent) of the main catalyst (A) and the cocatalyst compound (B) is preferably 10:1 to 1:10. If the content of the cocatalyst is less than the above range, the effect due to the addition of the cocatalyst is minimal, and if it is added in excessive amount, it is not economical.

The amount between the catalyst component including the main catalyst and cocatalyst compounds and the carrier can be appropriately controlled depending on the polymerization conditions and is not particularly limited.

In addition, the supported catalyst in which the main catalyst and cocatalyst compounds are supported on a carrier may further include an antistatic agent, and the method of adding the antistatic agent may be applied to both a method of treating in the catalyst preparation step and a method of treating after the catalyst preparation, and is not particularly limited. The antistatic agent may be included in an amount of 50 ppm to 5,000 ppm based on the weight of the supported catalyst, and if it is added in an amount less than 50 ppm, it is difficult to obtain the effect due to the use of the antistatic agent, and if it is used in an amount exceeding 500 ppm, it may cause agglomeration of catalyst particles.

In addition, the present invention can produce a polyethylene copolymer by copolymerizing ethylene and alpha-olefin in the presence of the metallocene supported catalyst as described above. At this time, the method for producing the polyethylene copolymer can produce the polyethylene copolymer in a liquid phase, a gas phase, a bulk phase, or a slurry phase.

At this time, olefin itself can be used as a medium for the polymerization reaction, or an organic solvent can be used. The organic solvent used in the above polymerization is not particularly limited, but preferably includes aliphatic hydrocarbon solvents such as butane, isobutane, pentane, hexane, cyclohexane, heptane, octane, nonane, decane, undecane, and dodecane; aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene, and toluene; or halogenated aliphatic hydrocarbon solvents such as dichloromethane, trichloromethane, dichloroethane, and trichloroethane.

In manufacturing the polyethylene copolymer according to the present invention, polymerization can be carried out in a batch type, a semi-continuous type, or a continuous type. At this time, the polymerization temperature can be in the range of 0 to 200°C, preferably 20 to 100°C. In addition, the polymerization pressure can be 1 to 100 bar, preferably 5 to 60 bar.

The weight average molecular weight of the polyethylene copolymer obtained according to the present invention is 10,000 to 1,000,000, preferably 100,000 to 300,000, and the molecular weight distribution (Mw/Mn) is 3.0 or more and 5.0 or less.

In addition, the polyethylene copolymer obtained according to the present invention has a bimodal distribution of a peak of a low molecular weight component and a peak of a high molecular weight component as a result of a GPC molecular weight distribution analysis, the peak of the high molecular weight component accounts for 10 to 40 wt%, the number of SCBs in the peak of the high molecular weight component is at least twice the number of SCBs in the peak of the low molecular weight component, and further, the amount of low molecular weight is less than 1 wt%.

Example

Hereinafter, the present invention will be described in more detail with reference to examples of synthesis of metallocene catalysts and examples of polymerization. However, the following examples are only examples of carrying out the present invention, and the present invention is not limited thereto.

<Example of manufacturing metallocene-supported catalyst>

All synthetic reactions were performed in an inert atmosphere such as nitrogen or argon, and standard Schlenk and glove box techniques were used.

Toluene was purchased as anhydrous grade from Sigma-Aldrich and then further dried by passing through an activated molecular sieve (4A) or activated alumina bed before use.

MAO (methylaluminoxane) was purchased as a 10% toluene solution (HS-MAO-10%) from Albemarle and silica was used as XPO2402 from Grace without additional treatment.

In addition, each catalyst compound used in the supported catalyst synthesis example was purchased and used without purification.

[Synthesis example of a supported catalyst 1]

In a glove box, 1 g of silica was placed in a flask, and 10 mL of toluene was added at room temperature to prepare a slurry of silica. The temperature of the prepared slurry of silica was lowered to 0°C, 8 mL of MAO was slowly added to the slurry of silica, stirred for 1 hour, and then increased to 70°C and reacted for 4 more hours to prepare a silica slurry. The temperature of the obtained silica slurry was lowered to 0°C again.

A mixture was prepared by mixing bis(1-butylindenyl)zirconium dichloride and racemic-dimethylsilylbis(2-methyl-4-phenylindenyl)zirconium dichloride in a molar ratio of 10:1 in a glove box, 46 μmol of the mixture was placed in a Schlenk flask, taken out of the glove box, and 10 mL of toluene was added to the Schlenk flask to completely dissolve it, thereby obtaining a catalyst compound solution.

The catalyst compound solution obtained above was slowly added to the silica slurry at room temperature, then the temperature was raised to 70°C and reacted for 1 more hour. Thereafter, the temperature was lowered to room temperature, stirring was stopped, the toluene layer was separated and removed, and then the solution was washed three times with normal hexane and vacuum was applied to remove all the solvent.

Thereby, a supported catalyst 1 in the form of a free flowing powder was obtained. It was confirmed that the Zr loading rate of the obtained supported catalyst 1 was 0.30 wt% and the Al loading rate was 13.0 wt%.

[Synthesis example of a catalyst supported 2]

A supported catalyst 2 was prepared in the same manner as in Supported Catalyst Synthesis Example 1, except that bis(1-butyl-3-methylcyclopentadienyl)zirconium dichloride and diphenylmethylene(n-butyl-cyclopentadienyl)(2,7-di-t-butyl-9-fluorenyl)zirconium dichloride were mixed and used as catalyst compounds in a molar ratio of 6:1.

It was confirmed that the Zr loading rate of the obtained supported catalyst 2 was 0.33 wt% and the Al loading rate was 14.1 wt%.

[Synthesis example of a catalyst supported on a substrate 3]

Supported catalyst 3 was prepared in the same manner as supported catalyst synthesis example 2, except that the catalyst compounds were mixed and used in a molar ratio of 25:1.

It was confirmed that the Zr loading rate of the obtained supported catalyst 3 was 0.42 wt% and the Al loading rate was 13.1 wt%.

[Synthesis example of a catalyst supported on a substrate 4]

A supported catalyst 4 was prepared in the same manner as in Supported Catalyst Synthesis Example 1, except that bisindenylzirconium dichloride and diphenylmethylene(n-butyl-cyclopentadienyl)(2,7-di-t-butyl9-fluorenyl)zirconium dichloride were used as catalyst compounds in a ratio of 1:1.

It was confirmed that the Zr loading rate of the obtained supported catalyst 4 was 0.20 wt% and the Al loading rate was 14.0 wt%.

[Synthesis example of a catalyst supported on a substrate 5]

Supported catalyst 5 was manufactured in the same manner as supported catalyst synthesis example 4, except that the catalyst compound usage ratio was 2:1.

It was confirmed that the Zr loading rate of the obtained supported catalyst 5 was 0.20 wt% and the Al loading rate was 14.0 wt%.

<Polyethylene polymerization>

All polymerizations were carried out in an autoclave, completely sealed from the outside air, after injecting the required amount of solvent, catalyst, ethylene, and alpha-olefin comonomer, and maintaining a constant ethylene pressure. Solvents such as toluene and n-hexane used for polymerization were purchased as anhydrous grade from Sigma-Aldrich, and then further dried by passing through an activated molecular sieve (4A) or an activated alumina bed before use. A 1.0 M triethylaluminum solution was purchased from Sigma-Aldrich and used.

[Example 1 and Comparative Examples 1 to 4]

Each of the above-synthesized supported catalysts 1 to 5 was applied to a pilot scale of a gas continuous process with an hourly production rate of 7 to 8 kg-PE/hr. Depending on the characteristics of the supported catalyst, the comonomer conditions for obtaining a density of 0.937 to 0.941 g/ml and the hydrogen conditions for obtaining properties of MI of 0.1 to 0.7 g/10 min were adjusted as shown in Table 1 and operated.

Reactor pressure 1-Hexene concentration (C ₆ /C ₂ mol ratio) H ₂ input (H ₂ /C ₂ ppm) Example 1 22 bar 0.008 25 Comparative Example 1 22 bar 0.002 400 Comparative Example 2 22 bar 0.006 50 Comparative Example 3 22 bar 0.004 90 Comparative Example 4 22 bar 0.005 60

The production activity and basic properties of the copolymer of ethylene and 1-hexene obtained therefrom were analyzed by the following methods, and the analysis results are shown in Tables 2 and 3 below.

<Polymer Analysis Method>

-Weight average molecular weight (Mw), molecular weight distribution (MWD)-

The weight-average molecular weight and molecular weight distribution were measured at 160°C using a PL-GPC 220 GPC analyzer from Agilent.

-Melting point and melting enthalpy (ΔH)-

Melting point and melting enthalpy were measured by heating at 10℃/min in the range of 25℃ to 200℃ in three steps using TA's Q-200 Differential Scanning Calorimetry (DSC).

-Melt Flow Index-

Melt Flow Index (MFI) was measured at 190℃ under a load of 2.16 kg according to ASTM D 1238, and high-load melt flow index was measured at 190℃ under a load of 21.6 kg according to ASTM D 1238.

The melt flow rate ratio (MFRR) was calculated by dividing the above high-load melt flow index by the melt flow index.

-density-

It was measured by the density gradient method according to ASTM D1505.

-Low molecule quantitative analysis-

According to ASTM D 5227, the weight specific gravity of the hexane soluble portion in the polyethylene copolymer was measured.

- Content ratio of low molecular weight components and high molecular weight components -

The GPC results were deconvoluted to separate the low molecular weight and high molecular weight peaks, and the molecular weight of each low molecular weight component and high molecular weight component was determined, and the low molecular weight content and high molecular weight content in the total polymer were derived from the deconvolution area ratio.

-Comonomer distribution analysis-

Analysis of the comonomer distribution was performed by obtaining the molecular weight distribution and SCB (units/1000TC) by fractions separated by crystallinity through the TREF step using a CFC (Polymer Char) device. The SCB (units/1000TC) represents the number of 1-hexene chains per 1000 carbons of ethylene chains.

-BOCD Index-

The GPC curve obtained from CFC was deconvoluted to obtain the SCB content values in the low molecular weight peak and the high molecular weight peak, and the BOCD index was calculated as follows to see how much higher the SCB content in the high molecular weight is compared to the SCB content in the low molecular weight.

BOCD index = (high molecular weight branch SCB content) / (low molecular weight branch SCB content)

catalyst Active
(kg-PE/g-cat) MI MFRR density (g/10min) (g/ml) Example 1 Supported catalyst 1 8.4 0.58 32 0.939 Comparative Example 1 Supported catalyst 2 6.5 0.70 22 0.939 Comparative Example 2 Supported catalyst 3 7.1 0.36 53 0.939 Comparative Example 3 Supported catalyst 4 8.6 0.10 105 0.937 Comparative Example 4 Supported catalyst 5 9.5 0.42 144 0.941

Mw MWD Tm
(℃) ΔH
(J/g) low molecule
dose
(wt%) Polymer composition SCB(dog/1000TC) BOCD
Index Low molecular weight Mw
(ratio) Mw (ratio) of high molecular weight low molecular weight components High molecular weight components Example 1 140,856 4.13 128.4 178.4 0.51 70 thousand
(70%) 330 thousand
(30%) 3.5 7.5 2.1 Comparative Example 1 141,800 5.56 127.0 178.2 1.74 10,000 (10%) 150 thousand
(90%) - - - Comparative Example 2 185,200 5.03 127.8 173.4 1.20 80,000 (87%) 560 thousand
(13%) 4.5 6.1 1.4 Comparative Example 3 234,100 12.72 124.5 166.1 1.68 30,000 (52%) 490 thousand
(48%) 6.6 8.3 1.3 Comparative Example 4 169,400 6.91 126.4 167.7 1.45 40,000 (73%) 530 thousand
(27%) 6.2 8.6 1.4

As can be seen from Table 2 above, in the results of Example 1, the MFRR was analyzed to be a value of 32 at the MI level of 0.6 g/10 min.

In addition, from Table 3 above, the polyethylene copolymer of Example 1 had a molecular weight of about 140,000, a molecular weight distribution of 4.13, and a low molecular weight quantitative value of 0.51 wt%, which is a low value of less than 1 wt%.

Meanwhile, it was found that the polymer composition had a bimodal distribution with low molecular weight components and high molecular weight components, and that the high molecular weight component had a content ratio of 30 wt%.

On the other hand, the polyethylene copolymers obtained in Comparative Examples 1, 3, and 4 have a very low molecular weight of less than 50,000 in the high molecular weight composition, and the difference from the high molecular weight is very large, so it can be confirmed that a copolymer with a very wide molecular weight distribution is obtained. Furthermore, the quantitative value of low molecules in the copolymer was extracted at a higher level than that in Example 1, at 1 to 2 wt%.

Meanwhile, in the case of Comparative Example 2, the molecular weight of the low-molecular weight portion is 80,000, which is not lower than that of the example, but the molecular weight of the high-molecular weight portion is 560,000, which is very high, so it can be interpreted that it is sensitive to hydrogen reactivity or that the content ratio of the low-molecular weight portion is high at 87 wt%, so the low-molecular weight portion is also high at 1.2 wt% or more.

When forming a pipe at high speed using a polyethylene copolymer such as Comparative Examples 1 to 4, workability may not be easy if the low molecular weight content is high. When forming at high speed using a polyethylene copolymer having a reduced low molecular weight content such as Example 1, improved workability can be expected.

Since long-term durability can be expected to be improved when comonomers are concentrated and distributed in high molecular weight components, some literatures use the BOCD index to identify comonomer distribution trends. However, this can lead to errors in interpreting comonomer distribution trends because the values vary depending on the selection of low molecular weight points and high molecular weight points. Therefore, the SCB content values at the low molecular weight peak position and the SCB content values at the high molecular weight peak position were read and compared.

As can be seen from the results in Table 2 above, the polyethylene copolymer of Example 1 produces a copolymer in which a higher proportion of comonomers distributed in high molecular weights is incorporated than comonomers distributed in low molecular weights, and thus, it can be seen that it has low-density characteristics.

<Pipe forming and pipe internal pressure test>

Pipe forming and pipe internal pressure characteristics according to polymer composition were tested as follows, and the results are shown in Table 4 below.

Pipe forming was performed by pelletizing using a single-axis granulator (Die = 40 mmΦ), and then forming into a pipe with an outer diameter of 30 mm and a thickness of 3 mm using a Battenfeld pipe forming extruder (Extruder Screw: L/D = 30, Die = 45 mmΦ).

The pipe extrusion amount was measured by weight of the amount of resin flowing out per 10 minutes under the same extrusion conditions and converted to weight per hour.

The fracture time was measured by applying hydrostatic pressure of the corresponding circumferential stress. To confirm the reproducibility of the fracture experiment, two samples were measured under each condition.

Pipe forming
Extrusion rate (kg/hr) Circular stress
(MPa) Destruction time ISO1167
Passing criteria time Sample-1 Sample-2 Example 1 9.6 4.5 41 39 - 4.2 >2700 - - Comparative Example 2 8.2 4.5 17 23 - 4.2 > 1000 - - Comparative Example 3 7.8 4.0 0.08 1.57 - 3.8 1.95 0.73 22 hours Comparative Example 4 8.0 4.0 3.98 3.74 - 3.8 > 113 78.80 22 hours

In the above Table 4, the pipe forming extrusion amount is compared with the extrusion amount under the same extrusion conditions (die temperature 205°C, 40 rpm) during pipe forming. When the polyethylene copolymer of Example 1 was used, a higher extrusion amount was shown compared to the comparative examples, and thus, it is expected that the line speed will be high in high-speed pipe forming.

Meanwhile, as a result of the pressure test, the polyethylene copolymer of Example 1 was confirmed to have improved high strength and long-term durability as it did not break for a long time at a higher circumferential stress than in the comparative examples.

Claims (12)

A hybrid supported metallocene catalyst in which a metallocene catalyst compound is supported on a carrier,
The above metallocene catalyst compound has a ligand composed of an indenyl skeleton,
A hybrid supported metallocene catalyst, wherein a first metallocene catalyst compound represented by chemical formula 1 and a second metallocene catalyst compound represented by chemical formula 2 are supported on a carrier:
[Chemical Formula 1]

In the above chemical formula 1,
M ¹ is an element in groups 3 to 10 of the periodic table,
X ¹ is selected from the group consisting of a halogen group, an amine group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group, a silyl (C ₆ to C ₂₀ ) aryl group, a (C ₁ to C ₂₀ ) alkoxy group, a (C ₁ to C ₂₀ ) alkylsiloxy group, and a (C ₆ to C ₂₀ ) aryloxy group,
k is determined by the oxidation number of the central metal and is an integer from 1 to 5,
Ind ¹ and Ind ² are ligands having an indenyl skeleton, which are the same or different and each independently;
[Chemical formula 2]

In the above chemical formula 2, M ² is an element of groups 3 to 10 on the periodic table,
X ² is selected from the group consisting of a halogen group, an amine group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group, a silyl (C ₆ to C ₂₀ ) aryl group, a (C ₁ to C ₂₀ ) alkoxy group, a (C ₁ to C ₂₀ ) alkylsiloxy group, and a (C ₆ to C ₂₀ ) aryloxy group,
n is determined by the oxidation number of the central metal and is an integer from 1 to 5.
Z is a component that does not directly coordinate to the transition metal M ² but connects the ligands Ind ³ and Ind ⁴ , and is selected from the group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N), and phosphorus (P).
R is selected from the group consisting of hydrogen, a (C ₁ ~C ₂₀ ) alkyl group, a (C ₃ ~C ₂₀ ) cycloalkyl group, a (C ₁ ~C ₂₀ ) alkylsilyl group, a silyl (C ₁ ~C ₂₀ ) alkyl group, a (C ₆ ~C ₂₀ ) aryl group, a (C ₆ ~C ₂₀ ) aryl (C ₁ ~C ₂₀ ) alkyl group, a (C ₁ ~C ₂₀ ) alkyl (C ₆ ~C ₂₀ ) aryl group, a (C ₆ ~C ₂₀ ) arylsilyl group, or a silyl (C ₁ ~C ₂₀ ) aryl group,
m is determined by Z and is an integer of 1 or 2,
Ind ³ and Ind ⁴ are ligands having an indenyl skeleton independently of each other. In the first paragraph, Ind ¹ and Ind ² is a hybrid supported metallocene catalyst, each independently represented by chemical formula 1-1:
[Chemical Formula 1-1]

In the above chemical formula 1-1, at least one of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ has a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) haloalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group or a silyl (C ₆ to C ₂₀ ) aryl group, and R ¹ , R ² , R Two or more of ^{R 3} , R ⁴ , R ⁵ , R ⁶ and R ⁷ may combine with each other to form a ring. In the first paragraph, the compound represented by the chemical formula 2 is a hybrid supported metallocene catalyst represented by the chemical formula 2-1:
[Chemical Formula 2-1]

(In the above chemical formula 2-1,
M ² , X ² , n, Z, R and m are as defined in chemical formula 2,
R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ are each independently selected from the group consisting of hydrogen, a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a silyl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) haloalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl (C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group or a silyl (C ₆ to C ₂₀ ) aryl group, and R ⁸ , R ⁹ , R ¹¹ , R ¹² and R ¹³ can be combined with two or more to form a ring,
R ¹⁰ is a (C ₆ ~C ₂₀ ) aryl group. In the third paragraph, the R ¹⁰ is an aryl group represented by the chemical formula 5, a hybrid supported metallocene catalyst:
[Chemical Formula 3]

(In the above chemical formula 3, R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ are each independently selected from the group consisting of hydrogen, a halogen group, a (C ₁ to C ₂₀ ) alkyl group, a (C ₃ to C ₂₀ ) cycloalkyl group, a (C ₁ to C ₂₀ ) alkylsilyl group, a (C ₁ to C ₂₀ ) silylalkyl group, a (C ₁ to C ₂₀ ) haloalkyl group, a (C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) aryl(C ₁ to C ₂₀ ) alkyl group, a (C ₁ to C ₂₀ ) alkyl(C ₆ to C ₂₀ ) aryl group, a (C ₆ to C ₂₀ ) arylsilyl group and a silyl(C ₆ to C ₂₀ ) aryl group, and R ¹⁴ , R ¹⁵ , R ¹⁶ , R ¹⁷ and R ¹⁸ may be combined with two or more of them to form a ring). A hybrid supported metallocene catalyst in claim 1, wherein the first metallocene catalyst compound and the second metallocene catalyst compound are included in a molar ratio of 10:1 to 1:10. In claim 1, a hybrid supported metallocene catalyst further comprising at least one cocatalyst compound selected from the group consisting of chemical formulae 4 to 6:
[Chemical Formula 4]
-[Al(R ¹⁷ )-O] _n -
(In chemical formula 4, Al is aluminum,
O is oxygen,
Y ¹ is halogen; or a (C ₁ -C ₂₀ )hydrocarbyl group substituted or unsubstituted with halogen,
n is an integer greater than or equal to 2);
[Chemical Formula 5]
Q(Y ² ) ₃
(In chemical formula 5, Q is aluminum or boron,
Y ² is independently a halogen or a (C ₁ -C ₂₀ ) hydrocarbyl group unsubstituted or substituted with a halogen);
[Chemical formula 6]
[W] ⁺ [Z ^a (A) ₄ ] ^-
(In chemical formula 6, W is a cationic Lewis acid or a cationic Lewis acid to which a hydrogen atom is bonded,
Z ^a is a group 13 element;
A is a (C ₆ -C ₂₀ )aryl group substituted with one or more substituents each independently selected from the group consisting of a halogen, a (C ₁ -C ₂₀ )hydrocarbyl group, an alkoxy group, and a phenoxy group; A (C ₁ -C ₂₀ )alkyl group substituted with one or more substituents selected from the group consisting of a halogen, a (C ₁ -C ₂₀ )hydrocarbyl group, an alkoxy group, and a phenoxy group. A method for producing a polyethylene copolymer, characterized in that the polyethylene copolymer is produced by reacting with one or more olefin monomers in the presence of a hybrid supported metallocene catalyst according to any one of claims 1 to 6. A method for producing a polyethylene copolymer in claim 7, wherein the olefin monomer is selected from _the group consisting of an α-olefin of (C ₂ to C ₂₀ ), a diolefin of (C ₄ to C ₂₀ ), a cycloolefin of (C 3 to C ₂₀ ), a cyclodiolefin of (C ₃ to C ₂₀ ), styrene and a styrene derivative. A polyethylene copolymer polymerized in the presence of a hybrid supported metallocene catalyst according to any one of claims 1 to 5, having a weight average molecular weight (Mw) of 100,000 to 300,000 and a molecular weight distribution (Mw/Mn) of 3.0 to 5.0. In claim 9, the polyethylene copolymer is a polyethylene copolymer having a GPC molecular weight distribution analysis result showing a bimodal distribution of a peak of a low molecular weight component and a peak of a high molecular weight component, and the peak of the high molecular weight component accounts for 10 to 40 wt%. A polyethylene copolymer, characterized in that in claim 10, the number of SCBs at the peak of a high molecular weight component is at least twice the number of SCBs at the peak of a low molecular weight component. A polyethylene copolymer having a low molecular weight content of less than 1 wt% in claim 9.