KR102060669B1 - Catalyst composition for preparing the multimodal polyolefin resin with the high melt strength - Google Patents

Abstract

[화학식 5]

[화학식 6]

상기 화학식 4, 5 및 6에서, R'은 탄화수소기이고, x는 1 내지 70의 정수이고, y는 3 내지 50의 정수이다.Disclosed are a metallocene catalyst composition for producing a multimodal polyolefin resin having high melt strength, excellent moldability, mechanical strength, processability, and appearance, and a multimodal polyolefin copolymer using the same. The catalyst composition may include (i) at least one first organic transition metal compound represented by Formula 1; (Ii) at least one second organic transition metal compound represented by formula (2); (Iii) at least one third organic transition metal compound represented by formula (3); And (iii) at least one promoter selected from the group consisting of aluminoxanes represented by the following formulas (4) to (6).
[Formula 1]
(L ¹ ) (L ² ) (X ¹ ) (X ² ) M ¹
In Formula 1, M ¹ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ¹ ) and (L ² ) are each independently a cyclopentadienyl group including at least one hydrocarbon substituent having 3 to 10 carbon atoms containing at least one secondary or tertiary carbon or at least one substituent containing silicon (Si) Is; (X ¹ ) and (X ² ) are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms.
[Formula 2]
(L ^3- (Q ¹ ) nL ⁴ ) (X ³ ) (X ⁴ ) M ²
In Formula 2, M ² is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ³ ) and (L ⁴ ) are each independently a cyclopentadienyl group, indenyl group or tetrahydroindenyl group having one or more substituted or unsubstituted hydrocarbon substituents or a substituent including silicon (Si); (Q ¹ ) n is a crosslinking functional group represented by the formula (Q ¹ R ¹ R ² ) n, wherein Q ¹ is a carbon atom, a silicon atom or a germanium atom; R ¹ and R ² are each independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; X ³ and X ⁴ are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1-5.
[Formula 3]
(L ^5- (Q ² ) nL ⁶ ) (X ⁵ ) (X ⁶ ) M ³
In Formula 3, M ³ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ⁵ ) is a fluorenyl group having two or more hydrocarbon substituents having 4 to 10 carbon atoms containing tertiary carbon; L ⁶ is a cyclopentadienyl group having one or more hydrocarbon substituents of 4 to 10 carbon atoms; (Q ² n) is a crosslinking functional group represented by the formula (Q ² R ³ R ⁴ ) n, wherein Q ² is a carbon atom, a silicon atom or a germanium atom, and R ³ and R ⁴ are independently hydrogen or 1 to 10 carbon atoms A hydrocarbon group of; X ⁵ and X ⁶ are independently F, Cl, Br, I or a hydrocarbon group of 1 to 10 carbon atoms; n is an integer of 1-5.
[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 4, 5 and 6, R 'is a hydrocarbon group, x is an integer of 1 to 70, y is an integer of 3 to 50.

Description

Catalyst composition for preparing multimodal polyolefin resin with high melt strength and multimodal polyolefin copolymer using the same

The present invention relates to a catalyst composition for producing a polyolefin resin and a multimodal polyolefin copolymer using the same, and more particularly, to produce a multimodal polyolefin resin having high melt strength and excellent moldability, mechanical strength, processability, and appearance. It relates to a metallocene catalyst composition and a multimodal polyolefin copolymer using the same.

In order to use a polyolefin resin for a specific use, the toughness, strength, environmental stress, crack resistance, etc. of a polyolefin resin should be excellent. Such properties can be relatively easily improved when the molecular weight of the polyolefin resin (polymer) is increased, but the moldability of the resin is deteriorated when the molecular weight of the polymer is increased. Because of these disadvantages, it is preferable to appropriately adjust the structure of the polymer or to use an appropriate processing aid while using a polyolefin resin having a single physical property alone rather than using a combination of polyolefin resins having different physical properties. However, in general, polyethylene resins prepared using Ziegler-Natta and metallocene catalysts have a narrow molecular weight distribution, and therefore, when used alone, various problems may occur. Therefore, when a polymer having a wide molecular weight distribution or a multimodal molecular weight distribution is used, not only the properties such as toughness, strength, environmental stress, crack resistance, etc. are maintained, but also the moldability is improved, thereby reducing the disadvantage of the polyolefin resin having a narrow molecular weight distribution. I can eliminate it.

A polyolefin having a multimodal molecular weight distribution means a polyolefin including two or more components having different molecular weights, for example, a polyolefin having a relatively balanced high molecular weight polyolefin and a low molecular weight polyolefin. In the past, many studies have been conducted to prepare polyolefins having a wide molecular weight distribution or a multimodal molecular weight distribution. One such method is a post-reactor or melt blending process in which polyolefins having two or more different molecular weights are blended together before or during processing. For example, US Pat. No. 4,461,873 discloses a method of physically blending polymers of two different physical properties to produce a bimodal polymeric blend. However, by using such a physical blend, a molded article having a high gel content is easy to be produced, and due to a poor appearance of the product due to the gel component, it cannot be used for a film or the like, and the physical blending method requires complete homogenization. Therefore, there are disadvantages such as an increase in manufacturing cost.

Another method for producing polyolefins having a multimodal molecular weight distribution, for example, polyolefins having a bimodal molecular weight distribution, is a method using a multistage reactor. The process using the multi-stage reactor uses two or more reactors, wherein a first polymer component having one of two different molecular weight distributions of the bimodal polymer in the first reactor is prepared under certain conditions, and The first polymer component is transferred to a second reactor, and a second polymer component having a molecular weight distribution different from the first polymer component in the second reactor is prepared under conditions different from the reaction conditions of the first reactor. The method using the multi-stage reactor can solve the problems associated with the gel, but because of the use of multiple reactors, there is a concern that the efficiency is lowered or the manufacturing cost is high, and when the high molecular weight component is produced in the first reactor, Since the low molecular weight component is not made in the two reactors, there is a problem that the final produced polyolefin particles may be composed of only the high molecular weight component.

Another method of preparing polyolefins having a broad molecular weight distribution or multimodal molecular weight distribution is to polymerize polyolefins using a catalyst mixture in a single reactor. Recently, various attempts have been made in the art to produce polyolefins having a broad molecular weight distribution or a multimodal molecular weight distribution using two or more different catalysts in a single reactor. Using this method, the resin particles are uniformly mixed at the subparticle level, so that resin components having different molecular weight distributions exist on the same phase. For example, US Pat. Nos. 4,530,914 and 4,935,474 describe ethylene or higher alpha- in the presence of a catalyst system comprising two or more metallocenes and aluminoxanes having different reaction evolution and termination rate constants. A method for producing a polyolefin having a wide molecular weight distribution by polymerizing olefins is disclosed. US Pat. Nos. 6,841,631 and 6,894,128 disclose bimodal using a metallocene catalyst containing at least two metal compounds. ) Or polyethylene having a multimodal molecular weight distribution, and the use thereof for the production of films, pipes, blow molded articles and the like is disclosed. The polyethylene thus produced has good workability, but the dispersion state of the polyethylene component for each molecular weight in the unit particles is not uniform, and even in relatively good processing conditions, the appearance is rough and physical properties are not stable.

U.S. Patent No. 4,937,299 discloses the preparation of polyolefins using a catalyst system comprising two or more metallocenes having different reaction ratios for the monomers to be polymerized, and U.S. Patent No. 4,808,561 describes In the presence, it is disclosed to prepare a supported catalyst by reacting metallocene with aluminoxane. The metallocene is supported on the support to form a solid powder catalyst. As the carrier, inorganic materials such as silica, alumina, silica-alumina, magnesia, titania, zirconia, and mixtures thereof, and resinous materials such as polyolefins (for example, finely divided polyethylene) were used. Aluminoxanes were deposited on the dehydrated support material.

Typically, polymers made with Ziegler-Natta catalysts alone or with metallocene catalyst systems have a narrow molecular weight distribution, and therefore cannot produce satisfactory polyolefins having a multimodal molecular weight distribution or a wide molecular weight distribution. Therefore, in the art, a method for producing a bimodal resin using a mixed catalyst system containing a Ziegler-Natta catalyst and a metallocene catalyst component is known. The mixed catalyst system or hybrid catalyst system typically comprises a combination of a heterogeneous Ziegler-Natta catalyst and a homogeneous metallocene catalyst. The mixed catalyst system is used for producing a polyolefin having a wide molecular weight distribution or a bimodal molecular weight distribution, and serves as a means for controlling the molecular weight distribution and the polydispersity of the polyolefin.

U.S. Patent 5,539,076 discloses a metallocene / nonmetallocene mixed catalyst system for preparing certain peak high density copolymers. The catalyst system is supported on an inorganic support, and the supported Ziegler-Natta and metallocene catalyst systems have a lower activity than the homogeneous homogeneous catalysts, which makes it difficult to produce polyolefins having characteristics suitable for use. There is a problem. In addition, since the polyolefin is produced in a single reactor, there is a fear that a gel generated in the blending method is produced, it is difficult to insert a comonomer in a high molecular weight portion, and there is a fear that the shape of the resulting polymer is poor. Since the branch polymer components are not uniformly mixed, there is a fear that quality control becomes difficult.

Korean Patent 1132180 discloses two or more metallocene mixed catalyst systems for producing multimodal polyolefin copolymers. The problem with the catalyst system is that the comonomer content of the low molecular weight portion of the bimodal polymer is not low. In order to satisfy the mechanical strength of the polymer and the long-term hydrostatic properties as a pipe, the content of comonomers in the low molecular weight portion and the content of the comonomer in the high molecular weight portion should be high. However, in the catalyst system, although the content of the comonomer is high in the high molecular weight portion, there is a fear that the long-term hydraulic pressure characteristics are deteriorated due to the comonomer contained in the low molecular weight portion. In addition, in the catalyst system, since the first metallocene to prepare a low molecular weight polymer has low hydrogen reactivity, there is a fear that it is difficult to control the molecular weight while maintaining an appropriate bimodal, Since the molecular weight is too high, the application flow index (MIE, 2.16 kg / 10 minutes) is too low, the application flow index ratio is too wide, there is a disadvantage that the mechanical properties of the molded body is lowered.

Korean Patent No. 1437509 discloses a catalyst composition and a polymerization method for producing a multimodal polyolefin resin having a low extrusion load during molding and a large amount of extrusion, and thus having high productivity. The multimodal polyolefin resin has been disclosed to exhibit excellent processability even though two or more different polymers are mixed and have a high molecular weight and a low melt flow index. However, these resins have the disadvantage that the surface is rough when processing large diameter pipes, and the journal POLYMER ENGINEERING AND SCIENCE, JULY 2004, Vol. 44, No. 7 1283-1294 shows that the molten resin under high stress during extrusion is extruded inside the extruder. It is described that the polymer chains move to make the energy balance due to the difference in elastic energy depending on the position. Compared with the general monomodal polyolefin, bimodal or multimodal polyolefin has a large difference in molecular weight of each polymer chain, and thus has a large elastic energy difference and easier movement of polymer chains. Therefore, even distribution of molecules is difficult and may cause problems such as surface roughness.

In addition, the conventional bimodal products have a very large difference in elastic energy between the polymer chains, so that when the polymer is subjected to a high stress during processing, the polymer chains having a relatively low molecular weight and a low elastic energy move toward a high stress extruder wall, and Polymer chains with high molecular weight and high elastic energy move toward the center of low stress. For this reason, polymer chains having low molecular weight are distributed in the outer surface direction of the manufactured molded article (for example, pipe, etc.), and thus there is a problem that surface roughness and melt fracture occur. Here, the melt fracture refers to a phenomenon in which the surface is unevenly and unevenly broken during polymer processing.

Accordingly, an object of the present invention is to provide a catalyst capable of producing a multimodal polyolefin resin having a molecular weight, molecular weight distribution and melt flow index ratio (SR) having a range suitable for molding under high stress extrusion conditions such as pipes and films. It is to provide a composition. Another object of the present invention is to produce a multi-modal polyolefin resin having a low extrusion load during molding and a low stress applied to the molten resin, thereby minimizing the elastic energy difference between the polymer chains, and having excellent appearance characteristics and excellent productivity. It is to provide a catalyst composition that can be. Another object of the present invention is a catalyst capable of producing a multimodal polyolefin resin having a high comonomer content in a high molecular weight portion, a very low comonomer content in a low molecular weight portion, low crosslinking of polyolefins, and high rigidity of a molded article. It is to provide a composition. Another object of the present invention is to provide a catalyst composition capable of producing a multimodal polyolefin resin which is particularly useful for molding pipes having excellent mechanical strength and pressure resistance characteristics.

In addition, another object of the present invention by using a new catalyst composition, by increasing the melt strength to inhibit the polymer chains having a relatively low molecular weight during the extrusion molding to move to the outside due to the energy difference, the distribution of the polymer chain throughout the molded body It is to provide an even multi-modal polyolefin resin.

In order to achieve the above object, the present invention (1) at least one first organic transition metal compound represented by the formula (1); (Ii) at least one second organic transition metal compound represented by formula (2); (Iii) at least one third organic transition metal compound represented by formula (3); And (iii) at least one cocatalyst selected from the group consisting of aluminoxanes represented by the following formulas (4) to (6).

[Formula 1]

(L ¹ ) (L ² ) (X ¹ ) (X ² ) M ¹

In Formula 1, M ¹ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ¹ ) and (L ² ) are each independently a cyclopentadienyl group including at least one hydrocarbon substituent having 3 to 10 carbon atoms containing at least one secondary or tertiary carbon or at least one substituent containing silicon (Si) Is; (X ¹ ) and (X ² ) are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms.

[Formula 2]

(L ^3- (Q ¹ ) nL ⁴ ) (X ³ ) (X ⁴ ) M ²

In Formula 2, M ² is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ³ ) and (L ⁴ ) are each independently a cyclopentadienyl group, indenyl group or tetrahydroindenyl group having one or more substituted or unsubstituted hydrocarbon substituents or a substituent including silicon (Si); (Q ¹ ) n is a crosslinking functional group represented by the formula (Q ¹ R ¹ R ² ) n, wherein Q ¹ is a carbon atom, a silicon atom or a germanium atom; R ¹ and R ² are each independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; X ³ and X ⁴ are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1-5.

[Formula 3]

(L ^5- (Q ² ) nL ⁶ ) (X ⁵ ) (X ⁶ ) M ³

In Formula 3, M ³ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ⁵ ) is a fluorenyl group having two or more hydrocarbon substituents having 4 to 10 carbon atoms containing tertiary carbon; L ⁶ is a cyclopentadienyl group having one or more hydrocarbon substituents of 4 to 10 carbon atoms; (Q ² n) is a crosslinking functional group represented by the formula (Q ² R ³ R ⁴ ) n, wherein Q ² is a carbon atom, a silicon atom or a germanium atom, and R ³ and R ⁴ are independently hydrogen or 1 to 10 carbon atoms A hydrocarbon group of; X ⁵ and X ⁶ are independently F, Cl, Br, I or a hydrocarbon group of 1 to 10 carbon atoms; n is an integer of 1-5.

[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 4, 5 and 6, R 'is a hydrocarbon group, x is an integer of 1 to 70, y is an integer of 3 to 50.

The present invention also provides a multimodal polyolefin copolymer obtained by polymerizing an olefin monomer in the presence of the catalyst composition.

The catalyst composition according to the present invention has high melt strength, uniform distribution of polymer chains throughout the molded body, low extrusion load during molding, and low stress on the molten resin, thereby minimizing the difference in elastic energy between the polymer chains. It is possible to produce a multimodal polyolefin resin having excellent appearance characteristics and excellent productivity.

1 is GPC data of polyethylene obtained in Comparative Examples 1 to 3 of the present invention.
2 is GPC data of polyethylene obtained in Examples 2 to 4 and Comparative Examples 2 to 5 of the present invention.
3 is a graph showing the relationship between the molecular weight and the melt strength of the polyethylene obtained in Examples 2 to 4 and Comparative Examples 2 to 5 of the present invention.
4 is a graph showing the relationship between the pulling rate and the melt strength of polyethylene obtained in Examples 2 to 4, Preparation Examples 1 to 3 and Comparative Example 2.
5 is a view showing a sampling position of a pipe formed of polyethylene obtained in Example 3, Comparative Example 2 and Comparative Example 5 of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in more detail the present invention. In the description below, polyolefin resins are simply referred to as polymers or polyolefins, or ethylene-based polymers, polymers, polymers, olefin polymers, and the like, as necessary.

The catalyst composition according to the present invention is for polymerizing a multimodal polyolefin used for molding a film, a pipe, or the like, specifically, a polyolefin having a wide molecular weight distribution or a bimodal molecular weight distribution. A first organic transition metal compound which is a catalyst system expressing a polymer; (ii) a second organic transition metal compound which is a catalyst system expressing a relatively medium molecular weight polymer; (iii) a third organic transition metal compound which is a catalyst system expressing a relatively high molecular weight polymer; And (iv) a promoter.

The first organic transition metal compound has a substituent containing secondary and tertiary carbons exhibiting a hindered effect, and serves as a catalyst for forming a low molecular weight polyolefin that is not bridged, and represented by Formula 1 below A first organic transition metal compound is included.

[Formula 1]

(L ¹ ) (L ² ) (X ¹ ) (X ² ) M ¹

In Formula 1, M ¹ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ¹ ) and (L ² ) are each independently a hydrocarbon group having 3 to 10 carbon atoms containing at least one secondary or tertiary carbon, preferably an alkyl group having 3 to 7 carbon atoms or silicon (Si) ) substituent groups containing preferably 1 to 10 carbon atoms, more preferably a cyclopentadienyl group containing at least one substituted or unsubstituted trimethylsilyl group (trimethylsily) with an alkyl group having 1 to 7; (X ¹ ) And (X ² ) are each independently F, Cl, Br, I or a hydrocarbon group of 1 to 10 carbon atoms. Here, (L ¹ ) and (L ² ) may be the same as or different from each other, each containing at least one secondary or tertiary carbon, but does not contain an aryl group, a hydrocarbon substituent having 3 to 10 carbon atoms, preferably It may be a cyclopentadienyl group containing at least one trimethylsilyl group unsubstituted or substituted with an alkyl group having 3 to 7 carbon atoms or silicon (Si), preferably an alkyl group having 1 to 10 carbon atoms. Here, the secondary or tertiary carbon included in the hydrocarbon substituent is a part for showing the steric hindrance effect. If necessary, the cyclopentadienyl group may be further substituted with a hydrocarbon group (substituent) having 1 to 4 carbon atoms (substituents) of 1 to 4 carbon atoms, preferably an alkyl group having 2 to 7 carbon atoms, in addition to the substituent indicating the steric hindrance, Adjacent substituents may be linked to each other to form a ring structure. For example, two hydrocarbon groups substituted with a cyclopentadienyl group may be linked to each other to form an indenyl group as a whole (see Formula 1h below) or to form a cyclohexane ring (see Formula 1i below).

The second organic transition metal compound has excellent polymerization activity, is bridged with an indenyl group and tetrahydroindenyl group, and serves as a catalyst for forming a medium molecular weight polyolefin, at least one second organic transition metal represented by the following formula (2) Compound.

[Formula 2]

(L ^3- (Q ¹ ) nL ⁴ ) (X ³ ) (X ⁴ ) M ²

In Formula 2, M ² is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ³ ) and (L ⁴ ) are each independently a cyclopentadienyl group, indenyl group or tetrahydroindenyl group having one or more substituted or unsubstituted hydrocarbon substituents or a substituent including silicon (Si); Preferably a hydrocarbon substituent not containing an aryl group or a substituent comprising silicon (Si) is at least one substituted or unsubstituted cyclopentadienyl group, indenyl group or tetrahydroindenyl group; (Q ¹ ) n is a bridged functional group represented by the formula (Q ¹ R ¹ R ² ) n, wherein Q ¹ is a carbon (C) atom, a silicon (Si) atom, or a germanium (Ge) atom; R ¹ and R ² are each independently hydrogen or a hydrocarbon group of 1 to 10 carbon atoms, preferably an alkyl group, alkenyl group, alkynyl group or cycloalkyl group of 2 to 8 carbon atoms; X ³ and X ⁴ are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms, preferably an alkyl group having 2 to 8 carbon atoms, an alkenyl group, an alkynyl group or a cycloalkyl group. n is an integer of 1-5.

The third organic transition metal compound includes a fluorenyl group crosslinked (bridged) with a cyclopentadienyl group having a hydrocarbon substituent having 4 to 10 carbon atoms, which has excellent polymerization activity and is effective in reducing long chain branch (LCB). , Which serves as a catalyst for forming a high molecular weight polyolefin, includes one or more third organic transition metal compounds represented by the following Chemical Formula 3.

[Formula 3]

(L ^5- (Q ² ) nL ⁶ ) (X ⁵ ) (X ⁶ ) M ³

In Formula 3, M ³ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ⁵ ) is a fluorenyl group having 2 or more, preferably 2 or more, hydrocarbon groups having 4 to 10 carbon atoms, preferably 4 to 8 carbon atoms or cycloalkyl groups containing tertiary carbon; L ⁶ is one or more hydrocarbon substituents of 4 to 10 carbon atoms, preferably one or more hydrocarbon substituents of 4 to 10 carbon atoms that do not contain aryl groups, more preferably one or more hydrocarbon substituents of 4 to 7 carbon atoms that does not contain aryl groups ( For example, it is a cyclopentadienyl group which has a C4-10 alkyl group, an alkenyl group, an alkynyl group, or a cycloalkyl group; (Q ² n) is a bridged functional group represented by the formula (Q ² R ³ R ⁴ ) n, wherein Q ² is a carbon (C) atom, a silicon (Si) atom, or a germanium (Ge) atom, and R ³ And R ⁴ is independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, for example, an alkyl group or an aryl group, preferably R ³ and R ⁴ are the same aryl group having 6 to 10 carbon atoms; X ⁵ and X ⁶ are independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms. Here, the tertiary carbon included in the hydrocarbon substituent of L ⁵ is a part for showing the steric hindrance effect. n is an integer of 1-5.

The promoter serves to remove activator function and impurities, and includes aluminoxane represented by the following formula (4). Wherein the aluminoxane may have a linear or net (Netweork) structure, for example, when the aluminoxane has a linear structure, it may be an aluminoxane represented by the following formula (5), when having a structure of cyclic aluminoxane It may be an aluminoxane represented by the formula (6) .

[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 4, 5 and 6, R 'is a hydrocarbon group, preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably, most of R' is a methyl group (for example, At least 50% of R ', preferably at least 80% is a methyl group), x is an integer from 1 to 70, preferably from 1 to 50, more preferably from 10 to 40, and y is from 3 to 50, preferably It is an integer of 10-40.

In the present invention, a commercially available alkyl aluminoxane may be used, and non-limiting examples of the alkyl aluminoxane include methyl aluminoxane, ethyl aluminoxane, butyl aluminoxane, isobutyl aluminoxane, hexyl aluminoxane and octyl aluminoxane. , Decyl aluminoxane, etc. can be illustrated. In addition, the aluminoxane is commercially available in various forms of a hydrocarbon solution, and among them, it is preferable to use an aromatic hydrocarbon solution aluminoxane, and more preferably to use an aluminoxane solution dissolved in toluene. The aluminoxanes used in the present invention may be used alone or in combination of two or more thereof. The alkylaluminoxane may be prepared by various conventional methods such as adding an appropriate amount of water to trialkylaluminum, or reacting a trialkylaluminum with a hydrocarbon compound or an inorganic hydrate salt containing water, and is generally linear and cyclic. Aluminoxanes are obtained in mixed form.

Hereinafter, the first organic transition metal compound represented by Chemical Formula 1 will be described in detail. In order to polymerize multimodal or bimodal polyolefins, a catalyst is required which forms a relatively low molecular weight polymer, for which the first organic transition metal compound is used. The higher the density of the low molecular weight polymer polymerized by the first organic transition metal compound, that is, the lower the comonomer content, the better the impact strength and long-term physical properties during molding of the polymer. The first first organic transition metal compound includes a ligand having a hydrocarbon substituent containing one or more secondary or tertiary carbons (ligands exhibiting a steric hindrance effect), so that when the comonomer is contacted, It inhibits the co-monomer coordination to the central metal, thereby increasing the density of the low molecular weight polymer. Preferred examples of the first metallocene compound represented by Chemical Formula 1 may include a compound represented by the following Chemical Formulas 1a to 1l.

[Formula 1a]

[Formula 1b]

[Formula 1c]

[Formula 1d]

 [Formula 1e]

[Formula 1f]

[Formula 1g]

[Formula 1h]

Formula 1i]

[Formula 1j]

[Formula 1k]

[Formula 1l]

[Formula 1m]

[Formula 1n]

[Formula 1o]

In Formulas 1a to 1o, M _a ¹ to M _o ¹ are each independently titanium (Ti), zirconium (Zr), or hafnium (Hf); R _a ¹ To R _o ¹ and R _a ² to R _o ² are each independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms; X _a ¹ to X _o ¹ and X _a ² to X _o ² are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 10 carbon atoms; n _a ¹ to n _o ¹ and n _a ² to n _o ² are each independently an integer of 0 to 10, preferably n _a ^{1 and 2} , n _e ^{1 and 2} and n _i ^{1 and 2} are each independently Integers from 0 to 7, n _b ^{1 and 2} , n _f ^{1 and 2} and n _j ^{1 and 2} are each independently an integer from 0 to 6, n _c ^{1 and 2} , n _d ^{1 and 2} , n _g ^{1 and 2} , n _h ^{1 and 2} , n _k ^{1 and 2} and n ₁ ^{1 and 2} are each independently an integer of 0 to 4.

Next, a second organic transition metal compound represented by Chemical Formula 2 will be described. The second organic transition metal compound represented by Formula 2 is a catalyst component capable of forming a polyolefin having a relatively medium molecular weight (for example, a weight average molecular weight of 50,000 to 200,000), and has excellent polymerization activity and a comonomer (comonomer). ) Insertion ability is superior to the catalyst component (first organic transition metal compound) forming a low molecular weight polyolefin, and lower than the catalyst component (third organic transition metal compound) forming a high molecular weight polyolefin. The polyolefin polymerized by the second organic transition metal compound, unlike the first organic transition metal compound and the third organic transition metal compound, including a ligand having a steric hindrance effect to inhibit the introduction of LCB in the molecular chain of the polyolefin, LCB may be included. According to the content of the molecular chain having an intermediate molecular weight of the entire molecular chain of the multi-modal polyolefin, the appearance of the appearance may be changed during the molding of the product (Melt Fracture). This means that when stressed at the time of forming the product at high temperatures, molecular chains having a relatively low molecular weight and molecular chains having a relatively high molecular weight are likely to be separated by chain transfer due to a difference in elastic energy. However, including the molecular chains of medium molecular weight can inhibit the movement and separation between the molecular chains can reduce the roughness of the appearance of the molded article.

The second organic transition metal compound may include, but is not limited to, a rigidly-bridged indenyl group and a tetrahydroindenyl group.

Preferred examples of the second organic transition metal compound represented by Chemical Formula 2 may include a compound represented by the following Chemical Formulas 2a to 2l.

[Formula 2a]

[Formula 2b]

[Formula 2c]

[Formula 2d]

[Formula 2e]

In Formulas 2a to 2e, M _a ² to M _e ² are each independently titanium (Ti), zirconium (Zr), or hafnium (Hf); R _a ³ to R _a ¹⁰ , R _b ³ to R _b ⁶ , R _c ³ to R _c ⁶ , R _d ³ to R _d ⁸ and R _e ³ to R _e ⁸ are each independently hydrogen or C 1-10 A cyclopentadienyl group including at least one trimethylsilyl group unsubstituted or substituted with a hydrocarbon substituent or a substituent including silicon (Si), preferably an alkyl group having 1 to 10 carbon atoms; Q _a ¹ to Q _e ¹ are hydrogen or a carbon (C) atom, a silicon (Si) atom or a germanium (Ge) atom having a hydrocarbon substituent of 1 to 10 carbon atoms; X _a ³ to X _e ³ and X _a ⁴ to X _e ⁴ are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is each independently an integer of 1-6.

Next, a third organic transition metal compound represented by Chemical Formula 3 will be described in detail. In order to polymerize multimodal or bimodal polyolefins, a catalyst is required which forms relatively high molecular weight polyolefins, for which a third organic transition metal compound is used. The lower the density of the high molecular weight polyolefin polymerized by the third organic transition metal compound, that is, the higher the comonomer content, the tie bodies between SCBs in the molecular chain (Tie Molecules), It is possible to provide a polyolefin resin having excellent impact strength and long-term hydraulic pressure resistance. On the other hand, when the long chain branch (LCB) in the molecular chain of the high molecular weight polymer (region) increases, flexible portions are irregularly generated inside the chain, and thus mechanical properties decrease. The third organic transition metal compound may be a cyclopenta having (i) a fluorenyl group having two or more hydrocarbon substituents of 4 to 10 carbon atoms containing tertiary carbon and (ii) one or more hydrocarbon substituents of 4 to 10 carbon atoms. The high molecular weight of the polymer by containing a dienyl group, and by allowing the two ligands to be bridged (Bridge), when contacting the comonomer during the olefin polymerization process, the LCB having a large molecular chain is coordinated to the central metal through steric hindrance In the region, the introduction of LCB can be suppressed and the content of SCB can be increased. More specifically, according to the substituent bonded to the cyclopentadienyl group of the third organic transition metal compound, it is possible to control the activity and molecular weight of the polymer, a compound having a hydrocarbon group of at least 4 carbon atoms is the first organic transition metal compound and It was effectively combined with the second organic transition metal compound (see Examples below). More specifically, despite the presence of substituents that exhibit steric hindrance effects on the fluorenyl group, the ligands are bridged, thus widening the reaction space of the monomers and not completely blocking the introduction of LCB. Therefore, in order to further suppress the introduction of LCB, the third organic transition metal compound has a hydrocarbon group having at least 4 carbon atoms or more in a cyclopentadienyl group. Since the third organic transition metal compounds represented by Chemical Formula 3 include ligands having a steric hindrance effect, they inhibit the introduction of LCB in the polyolefin molecular chain and do not prevent the introduction of relatively small SCB.

Preferred examples of the third organic transition metal compound represented by Chemical Formula 3 may include compounds represented by the following Chemical Formulas 3a to 3c.

[Formula 3a]

[Formula 3b]

[Formula 3c]

In Chemical Formulas 3a to 3c, M is titanium (Ti), zirconium (Zr) or hafnium (Hf); R ¹ and R ² are independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; R ³ , R ⁴ and R ⁵ are independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; Q is a carbon atom, silicon atom or germanium atom; X ¹ and X ² are independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1 to 7.

In the catalyst for olefin polymerization used in the present invention, the amount of the second organic transition metal compound represented by Chemical Formula 2 is 0.01 to 100 moles, preferably 1 mole of the first organic transition metal compound represented by Chemical Formula 1 above. Preferably from 0.1 to 20 moles, more preferably from 0.5 to 10 moles. In addition, the amount of the third organic transition metal compound represented by Chemical Formula 3 is 0.01 to 100 moles, preferably 0.1 to 20 moles, more preferably 0.5 to 10 moles with respect to 1 mole of the first organic transition metal compound. . Here, if the amount of the first organic transition metal compound represented by the formula (1) is too small, there is a fear that a mainly high molecular weight polymer is made, if too much, there is a fear that a mainly low molecular weight polymer is made.

The amount of the aluminoxane used is based on 1 mole of the total of the first organic transition metal compound represented by Formula 1, the second organic transition metal compound represented by Formula 2, and the third organic transition metal compound represented by Formula 3, Aluminum of aluminoxane may be used to mix 1 to 100,000 moles, preferably 1 to 5,000 moles, more preferably 1 to 2,500 moles. For example, the first second and third organic compounds may be used in an amount of 1 to 100,000 moles, preferably 1 to 5,000 moles, and more preferably 1 to 2,500 moles, based on 1 mole of the total organic transition metal compound. The catalyst for olefin polymerization according to the present invention may be prepared by mixing a transition metal compound and aluminoxane.

Mixing of the catalyst components may be optionally performed without particular limitation. For example, the organometallic compound (first, second and third organic transition metal compound) and aluminoxane may be mixed simultaneously for 5 minutes to 24 hours, preferably 15 minutes to 16 hours. The mixing may also first mix the first organic transition metal compound and the aluminoxane for 5 minutes to 10 hours, preferably 15 minutes to 4 hours, and then to the mixture of the second organic transition metal compound and the aluminoxane. The third organic transition metal compound and the aluminoxane were mixed for 5 minutes to 10 hours, preferably 15 minutes to 4 hours, in a solution mixed for 5 minutes to 24 hours, preferably 15 minutes to 16 hours. The solution may be added and mixed for 5 minutes to 24 hours, preferably 15 minutes to 16 hours. The mixing may be performed under an inert atmosphere of nitrogen or argon, without using a solvent, or in the presence of an inert hydrocarbon solvent such as heptane, hexane, benzene, toluene, xylene, or a mixture thereof, The temperature is 0 to 150 ° C, preferably 10 to 100 ° C. The catalyst in a solution state uniformly dissolved in the hydrocarbon solvent or the like may be used as it is, or may be used in a solid powder state in which the solvent is removed. The catalyst in the solid powder state solidifies the precipitate after precipitating the catalyst in the solution state. It can also manufacture by the method of making.

The catalyst composition used in the present invention may be in the form of a carrier in which a mixture of the organic metal compound (first to third organic transition metal compound) and aluminoxane is supported on an organic or inorganic carrier. Thus, the catalysts used in the present invention may be present in the form of a solid powder or a solution in a homogeneous solution, as well as a form supported on an organic or inorganic porous carrier (silica, alumina, silica-alumina mixture, etc.) or insoluble particles of the carrier. It includes a catalyst. The method of contacting (supporting) the catalyst in solution with the porous carrier is as follows, but is not limited to the following method. The supporting method is a solution in the form of a catalyst prepared by mixing the organometallic compound, the first to third organic transition metal compound and the aluminoxane, the porous carrier (for example pore size of 50 to 500 mm 3 and 0.1 to 5.0 Contacting a silica carrier having a pore volume of cm 3 / g) to a slurry state; In the slurry mixture, acoustic or vibrational waves in the frequency range of 1 to 10,000 kHz, preferably 20 to 500 kHz, are 0.1 to 6 hours at 0 to 120 ° C, preferably 0 to 80 ° C, preferably 0.5 to Acting for 3 hours to uniformly infiltrate the catalyst components deep into the micropores of the porous carrier; And drying the catalyst components penetrated into the micropores of the porous carrier by vacuum treatment or nitrogen flow, and through this step, a catalyst in the form of a solid powder may be prepared. The acoustic wave or vibration wave is preferably ultrasonic waves. The supported method (supporting method) of the catalyst and the support is to add the acoustic or vibration wave, and then use the hydrocarbon selected from the group consisting of pentane, hexane, heptane, isoparaffin, toluene, xylene, and mixtures thereof to carry out the supported catalyst. The process may further include washing.

As the porous carrier, a porous inorganic material, an inorganic salt or an organic compound having fine pores and a large surface area can be used without limitation. The inorganic (inorganic salt or inorganic) carrier in the porous carrier may be used without limitation as long as it can obtain a predetermined form in the process for preparing the supported catalyst, and may be in the form of powder, particles, flakes, foils, fibers, or the like. Can be illustrated. Regardless of the form of the inorganic carrier, the maximum length of the inorganic carrier is 5 to 200 μm, preferably 10 to 100 μm, the surface area of the inorganic carrier is 50 to 1,000 m 2 / g, and the void volume is 0.05 to 5 cm 3. / g is preferred. In general, the inorganic carrier must undergo a water or hydroxy group removal process before use, which can be carried out by calcining the carrier to a temperature of 200 to 900 ℃ in an inert gas atmosphere such as air, nitrogen, argon or the like. Non-limiting examples of the inorganic salts or inorganic materials include silica, alumina, bauxite, zeolite, magnesium chloride (MgCl ₂ ), calcium chloride (CaCl ₂ ), magnesium oxide (MgO), zirconium oxide (ZrO ₂ ), Silica-magnesium oxide (TiO ₂ ), boron oxide (B ₂ O ₃ ), calcium oxide (CaO), zinc oxide (ZnO), barium oxide (BaO), thorium oxide (ThO ₂ ) or mixtures thereof SiO ₂ -MgO), silica-alumina (SiO ₂ -Al ₂ O ₃ ), silica-titanium oxide (SiO ₂ -TiO ₂ ), silica-vanadium pentoxide (SiO ₂ -V ₂ O ₅ ), silica-chromium oxide ( SiO ₂ -CrO ₃ ), silica-titanium oxide-magnesium oxide (SiO ₂ -TiO ₂ -MgO) or compounds containing small amounts of carbonate, sulfate or nitrate in these compounds, etc. Non-limiting examples of the organic compound may include starch, cyclodextrin, synthetic polymers, and the like. The solvent used to contact the catalyst in the solution state with the porous carrier is an aliphatic hydrocarbon solvent such as pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, benzene, monochlorobenzene, dichlorobenzene, Aromatic hydrocarbon solvents, such as trichlorobenzene and toluene, and halogenated aliphatic hydrocarbon solvents, such as dichloromethane, trichloromethane, dichloroethane, and trichloroethane, can be used. When the catalyst for olefin polymerization used in the present invention is supported on a carrier, the composition of each component of the catalyst is the same as that of a catalyst in a solution or solid state, and the supported amount of the aluminum component of the catalyst for olefin polymerization is 100% by weight of the carrier. The amount is 5 to 30 parts by weight, preferably 7 to 20 parts by weight, and the supported amount of the transition metal component of the catalyst is 0.01 to 2 parts by weight, preferably 0.05 to 1.5 parts by weight.

Next, the polymerization method of the polyolefin which concerns on this invention is demonstrated. Since the catalyst composition is present in the form of an insoluble particle of a carrier or a form supported on an organic or inorganic porous carrier as well as a homogeneous solution, the polyolefin according to the present invention may be a liquid phase, a slurry phase, a bulk phase or a gas phase reaction. Can be polymerized. In addition, each polymerization condition may be appropriately modified depending on the state of the catalyst used (uniform or heterogeneous phase (supported type)), the polymerization method (solution polymerization, slurry polymerization, gas phase polymerization), the desired polymerization result or the form of the polymer. Can be. When the polymerization is carried out in a liquid phase or a slurry phase, a solvent or olefin itself may be used as a medium. The solvent includes propane, butane, pentane, hexane, octane, decane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, dichloromethane, chloroethane, 1,2-dichloroethane, chloro Benzene etc. can be illustrated and these solvent can also be mixed and used in fixed ratio. In the polymerization or copolymerization of the olefin of the present invention, the amount of the first to third organic transition metal compounds is not particularly limited, but the central metal concentration of the first to third organic transition metal compounds in the reaction system used for polymerization is It is preferable that it is 10-8-10 mol / L, and it is more preferable if it is 10-7-10-10 mol / L.

In the polymerization or copolymerization of the olefin according to the present invention, the polymerization temperature is not particularly limited because it may vary depending on the reaction material, reaction conditions and the like, but is usually 70 to 110 ° C. Specifically, the polymerization temperature is 0 to 250 ° C., preferably 10 to 200 ° C. when performing solution polymerization, and 0 to 120 ° C., preferably 20 to 110 ° C. when performing slurry or gas phase polymerization. . In addition, the polymerization pressure is from atmospheric pressure to 500 kgf / ㎠, preferably atmospheric pressure to 60 kgf / ㎠, more preferably 10 to 60 kgf / ㎠, the polymerization may be carried out batch, semi-continuous or continuous. . The polymerization can also be carried out in two or more stages with different reaction conditions, the molecular weight and molecular weight distribution of the final polymer prepared using the catalyst according to the invention is a method of changing the polymerization temperature or injecting hydrogen into the reactor Can be adjusted. Polymerization of the polyolefin resin according to the present invention, a conventional single loop reactor, gas phase reactor, internally circulating fluidized bed (ICFB) reactor (see Korean Patent Nos. 961612, 999543, 999551, etc.). Can be performed using

The polyolefin according to the present invention may be polymerized through a prepolymerization and a main polymerization process. In the prepolymerization process, the olefin polymer or copolymer is preferably produced in 0.05 to 500 g, preferably 0.1 to 300 g, more preferably 0.2 to 100 g per g of the olefin catalyst. Olefins usable in the prepolymerization process are ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1- C2-C20 alpha olefins, such as tetradecene, 3-methyl-1- butene, 3-methyl-1- pentene, etc. can be illustrated, It is preferable to use the same olefin as used at the time of superposition | polymerization. .

The multimodal polyolefin resin obtained by using the catalyst composition according to the present invention is a polyolefin resin having a wide molecular weight distribution, for example, a bimodal or multimodal molecular weight distribution, and is excellent in moldability, such as a blow molding method, an extrusion molding method, and a film. Particularly suitable for the molding method, the mechanical strength and appearance of the molded body are excellent.

In addition, the multimodal polyolefin copolymer prepared using the catalyst composition according to the present invention has a melt index ratio (SR = MIF / MIP) of 20 to 200, preferably 20 to 100, and more preferably 20 to 50. Here, MIF is the high load melt flow index measured according to ASTM D1238 at 21.6 kg / 10 min and 190 ° C., and MIP is the melt flow index measured according to ASTM D1238 at 5.0 kg / 10 min and 190 ° C.

The molecular weights of the polymers obtained at the position A and the position B of the following definition 1 were measured and compared by gel permeation chromatography (GPC) in a pipe formed by using the multimodal polyolefin resin obtained using the catalyst composition according to the present invention. At that time, the following requirements (1) to (6) are satisfied.

(1) When molecular weight is measured by gel permeation chromatography (GPC), two or more peaks appear. Here, the polyolefin forming the peak molecular weight peak (MHp) improves the mechanical properties and melt strength of the polymer resin, the polyolefin forming the peak molecular weight peak (MLp) has a function to improve the moldability of the polymer resin do.

(2) The weight average molecular weight (Mw) of the polymer taken at the position B of the following definition 1 in the pipe formed by molding is 0.1, preferably 1, more preferably than the weight average molecular weight (Mw) of the polymer taken at the position A Exceeds 2%.

(3) In a molded pipe, a polymer having a weight average molecular weight (Mw) of a polymer taken at position A of definition 1 below 10,000 or less and a polymer having a weight average molecular weight (Mw) of a polymer taken at position B below 10,000 More than 0.1, preferably 1, more preferably 2%.

(4) In a molded pipe, a polymer having a weight average molecular weight (Mw) of a polymer taken at position B of the following definition 1 of 1,000,000 or more and a polymer having a weight average molecular weight (Mw) of at least 1,000,000 of a polymer taken at position A It is more than 0.1, preferably 1, more preferably 2% more than the content.

(5) The Z average molecular weight (Mz) measured by gel permeation chromatography (GPC) of the polymer taken at the position B of the following definition 1 in the pipe in which the molding was formed is greater than the Z average molecular weight (Mz) of the polymer taken at the position A 0.1%, preferably greater than 1%. The Z average molecular weight is preferably 100,000 to 10,000,000, more preferably 200,000 to 5,000,000, most preferably 500,000 to 3,000,000.

(6) Z + 1 average molecular weight (Mz + 1) measured by gel permeation chromatography (GPC) of a polymer taken at position B of the following definition 1 in a pipe formed with Z + 1 of a polymer taken at position A The average molecular weight (Mz + 1) is more than 1%, preferably 5%. The Z + 1 average molecular weight is preferably 1,000,000 to 10,000,000, more preferably 500,000 to 5,000,000, and most preferably 1,000,000 to 3,000,000.

[Definition 1]

In pipes with a standard dimension ratio, SDR = od / en (Standard Dimension Ratio) of 2 to 20,

Where id is the inner diameter, od is the outside diameter, and en is the wall thickness.

As the olefin monomer forming the polyolefin resin using the catalyst composition according to the present invention, a linear aliphatic olefin having 2 to 12 carbon atoms, preferably 2 to 10 carbon atoms, a cyclic olefin having 3 to 24 carbon atoms, preferably 3 to 18 carbon atoms, Dienes, trienes, styrenes and the like can be used. Examples of the linear aliphatic olefins include ethylene, propylene, butene-1, pentene-1, 3-methylbutene-1, hexene-1, 4-methylpentene-1, 3-methylpentene-1, heptene-1, and octene-1. , Decene-1 (decene-1), 4,4-dimethyl-1-pentene, 4,4-diethyl-1-hexene, 3,4-dimethyl-1-hexene and mixtures thereof and the like can be exemplified. . As the cyclic olefin, cyclopentene, cyclobutene, cyclohexene, 3-methylcyclohexene, cyclooctene, tetracyclodecene, octacyclodecene, dicyclopentadiene, norbornene, 5-methyl-2- Norbornene, 5-ethyl-2-norbornene, 5-isobutyl-2-norbornene, 5,6-dimethyl-2-norbornene, 5,5,6-trimethyl-2-norbornene , Ethylene norbornene and mixtures thereof and the like can be exemplified. As the dienes and trienes, polyenes having 4 to 26 carbon atoms having two or three double bonds are preferable. Specifically, 1,3-butadiene, 1,4-pentadiene, 1,4-hexa Dienes, 1,5-hexadiene, 1,9-decadiene, 2-methyl-1,3-butadiene, mixtures thereof, and the like. As the styrene, styrene substituted with styrene or an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 1 to 10 carbon atoms, a halogen group, an amine group, a silyl group, an alkyl halide group, a mixture thereof, and the like are preferable. The olefin monomers may be homopolymerized or alternating, random, or block copolymerized.

Preferably, the polyolefin resin obtained using the catalyst composition according to the present invention is ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-aitocene, norbornene, norbonadiene, ethylidenenorbornene, phenylnorbornene, vinylnorbornene, di Cyclopentadiene, 1,4-butadiene, 1,5-butadiene, 1,5-pentadiene, 1,6-hexadiene, styrene, alpha-methylstyrene, divinylbenzene, 3-chloromethylstyrene and mixtures thereof Homopolymers or copolymers of olefin monomers selected from the group consisting of:

In addition, the polyolefin resin obtained by using the catalyst composition according to the present invention, the main component is selected from the group consisting of ethylene, propylene and mixtures thereof, and as the remaining auxiliary components, 4 to 10 carbon atoms, for example, It is preferable to contain 0.01 to 3.0% by weight of structural units derived from α-olefins. Here, the content of the comonomer (α-olefin) can be measured by 13 C-NMR.

When the polyolefin resin obtained using the catalyst composition which concerns on this invention shape | molds a pipe, it is preferable that the shape | molding pipe further satisfy | fills the conditions of following (7) and (8).

(7) In a pipe hydrostatic test in which the pipe breakage time is measured by applying a stress corresponding to a pressure of 5.4 Mpa with water at 80 ° C. according to KS M 3408, the pipe break time exceeds 165, preferably 200 hours. do.

(8) In a pipe hydrostatic test in which the pipe breakage time is measured by applying a stress corresponding to a pressure of 12.4 Mpa with water at 20 ° C. according to KS M 3408, the pipe break time exceeds 100, preferably 200 hours. do.

The polyolefin resin obtained using the catalyst composition according to the present invention has a higher molecular weight of the polymer located on the outer surface of the finished molded article (for example, a pipe) than the molecular weight of the polymer located at the center, so that the outer surface of the molded article is excellent (smooth). . The polyolefin resin according to the present invention includes a polymer having a relatively high molecular weight compared to a polymer having a low molecular weight (relatively higher than a polymer having a low molecular weight) and having a low molecular weight compared to a polymer having a high molecular weight (relative to a polymer having a high molecular weight). Low molecular weight polymer), in the polyolefin resin (when molding the polyolefin resin), the chain transfer phenomenon caused by the friction energy difference depending on the position can be alleviated, so that the outer surface of the molded body can be excellently produced. That is, in the chain transfer phenomenon, the chain of medium length serves to prevent (suppress) the movement of polymer having a long chain inwards (center).

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples are intended to illustrate the invention, and the invention is not limited by the following examples. In the examples below, the catalysts were prepared by Schlenk technique in which air and moisture were completely blocked, and purified dry nitrogen was used as the inert gas. In addition, the solvent was dried over sodium metal in an inert nitrogen atmosphere. In this specification and an Example, the measuring method of each physical property is as follows.

(1) Density: Measured according to ASTM 1505 and ASTM D 1928.

(2) Melt Flow Index (MIP, 5.0 kg / 10 min): Measured according to ASTM D1238 at 190 ° C.

(3) High Load Melt Flow Index (MIF, 21.6 kg / 10min): Measured according to ASTM D1238 at 190 ° C.

(4) Melt Flow Index (SR): High Load Melt Flow Index (MIF) / Melt Flow Index (MIP)

(5) GPC Molecular Weight and Molecular Weight Distribution (Mw, Mz, Mz + 1, MWD): The gel permeation chromatography (GPC, manufactured by Polymer Laboratory Inc., product 220) was measured as follows. Two Olexis and one Guard were used for the separation column, and the column temperature was maintained at 160 ° C. Calibration was performed using a standard set of polystyrene from Polymer Laboratory, and the eluent used trichlorobenzene containing 0.0125% by weight of dibutyl hydroxyl toluene (BHT) as an antioxidant. Samples were prepared at a rate of 0.1 to 1 mg / ml, the injection amount was 0.2 ml, the injection time was 30 minutes, the pump flow rate was measured for 30 to 60 minutes to maintain 1.0 ml / min. Universal calibration was performed using Easical A and Easical B (Agilent), which were polystyrene standards, and then converted into polyethylene to measure number average molecular weight (Mn), weight average molecular weight (Mw), and z average molecular weight (Mz). A refractive index (RI) detector was used as the detector. Molecular weight distribution (Mw / Mn) shows the ratio of a weight average molecular weight and a number average molecular weight.

(6) Low molecular weight content (LMW%): Using the program (Origin Pro 8.6), using the data of GPC analyzed in (5) and Gaussian law, only the low molecular weight content is extracted to determine the total amount. It was.

(7) Cross fractionation chromatography (CFC): Cross fractionation chromatography (CFC, PolymerChar Inc.) was measured as follows. Two Olexis and one Guard were used for the separation column, and the column temperature was maintained at 150 ° C. Calibration was carried out using a standard polystyrene set by Polymer Laboratory, trichlorobenzene as the eluent, and the sample was prepared at a concentration of 70 to 80 mg / ml, a dose of 0.5 ml, and a pump flow rate of 1.0 ml / min. After the sample was injected, the oven temperature was raised to 40 ° C./min to 150 ° C. After holding at 150 ° C. for 60 minutes, the temperature was lowered to 40 ° C./min to lower the temperature of the sample to 95 ° C. After 45 minutes of holding at 95 ° C, the temperature was lowered to 30 ° C at 0.5 ° C / min and held for 30 minutes. The sample was then heated to 35 ° C. to 120 ° C., divided into 22 fractions by temperature at 4 ° C., 0.5 mL of sample was injected for each fraction, and the elution fractions were TREF column and Olexis column. The TREF value and molecular weight were measured while going through. Next, the PE conversion molecular weight was calculated using the calibration curve using a standard polystyrene set. Data processing was carried out using "CFC calibration" which is a device analysis program. It took about 600 minutes to complete the analysis, and the infrared spectrometer was used as a detector.

(8) Melt Tension: It was measured as follows using a capirograph (Capirograph 1B, manufactured by Toyoseiki). Using a capillary tube of 10 mm in length and 1.0 mm in diameter, 5-10 g of pellet sample was measured at 230 ° C., speed 10 mm / min, and draw 30 m / min. The average value was obtained by measuring three times per sample.

(9) Tensile Strength at Yield: Measured according to ASTM D638. The test speed was 50 mm / min, and the average value was obtained by measuring five times per specimen.

(10) Elongation: measured according to ASTM D638. The test speed was 50 mm / min, and the average value was obtained by measuring five times per specimen.

(11) Flexural Modulus: Measured according to ASTM D790. Measurement was made up to 5% strain, and the average value was obtained by measuring five times per specimen.

(12) Izod Impact: Measured according to ASTM D256. The width and thickness of the test piece were measured, a V-notch was formed, an impact was applied to the test piece, and the impact strength value was measured. At least five measurements were taken to obtain an average value.

(13) Pipe water pressure test: Measured according to KS M ISO 1167. A pipe having an outer diameter of 34 mm and a thickness of 3.5 mm was placed in water at 20 ° C., and a circumferential stress corresponding to a pressure of 12.4 MPa was applied to the inside of the pipe to measure the time at which the pipe was broken. Into a pipe having an outer diameter of 34 mm and a thickness of 3.5 mm, a circumferential stress corresponding to a pressure of 5.4 MPa was applied to the inside of the pipe, and the time for the pipe to break was measured.

(14) Appearance of pipe: It was judged as good, normal, or poor by visual observation.

(15) Evaluation of product formability: Using a pipe extruder (manufactured by Wonil Engineering Co., Ltd., 16Φ Die Dia., 41Φ Screw Dia.), The outer diameter was 34 mm and the thickness was 3.5 mm at the extrusion temperature (Die temperature) of 200 ° C. The pipe was extruded.

(15a) Resin Melt Pressure (bar): Under the above processing conditions, the resin melt pressure generated at the extrusion site was measured when the pipe was extruded.

(15b) Extrusion amount (g / min): Under the above processing conditions, when extruding the film and the pipe, the weight of the resin extruded per minute was measured.

(16) Viscosity ratio (Shear Thining Index, STI): Measured using the following formula (1). Rhometrics Mechanical Spectrometer (RMS-800) was used and the method was a plate (Parallel Plate), the diameter was 25 mm, the temperature was measured at 190 ℃.

[Equation 1]

STI = η0.1 / η100

Here, η 0.1 is the viscosity at a strain of 0.1 rad / s and η 100 is the viscosity at a strain of 100 rad / s.

(17) Modulus Ratio Index (MRI): Measured using the following Equation 2. Rhometrics Mechanical Spectrometer (RMS-800) equipment was used, and the method was a parallel plate, and was measured at a diameter of 25 mm and a temperature of 190 ° C.

[Equation 2]

MRI = G'100 / G'0.1

Where G'0.1 is Storage Modulus at 0.1 rad / s strain and G'100 is Storage Modulus at 100 rad / s strain.

(18) Long Chain Branch (1,000C): Measured using the following Equation 3 (Reference: Macromolecules 1999, 32, 8454-8464).

[Equation 3]

LCBI = η00.196 / [η] x 1 / 4.7-1

Here, η 0 is Zero shear viscosity at 190 ° C. and [η] is Intrinsic viscosity at 150 ° C.

(19) Relaxation time, s (Relaxation Time, tau 0): Measured using the following equation 4.

[Equation 4]

η = η0 / (1 + (γτ0) n)

Here, n is the power law index of the material, η is the measured viscosity (complex viscosity), γ is the strain rate, shear rate (x-axis value in the RMS frequency sweep according to the Cox-Mertz rule).

Preparation Example 1 Preparation of Catalyst Containing First Organic Transition Metal Compound

In a nitrogen atmosphere, bis (isobutylcyclopentadienyl) zirconium dichloride ((iBuCp) ₂ ZrCl ₂ ) and methylaluminoxane (MAO, manufactured by Albemarle, 10% toluene) as a first organic transition metal compound in a shrink flask Solution) was mixed and stirred at room temperature for 30 minutes to prepare a solution. In the solution, calcined silica (SiO ₂ ) at a temperature of 250 ° C. was added thereto for 1 hour, and then the supernatant was removed. Next, the remaining solid particles were washed twice with hexane, and then dried under vacuum to prepare a supported catalyst of free flowing solid powder.

Preparation Example 2 Preparation of Catalyst Containing Second Organic Transition Metal Compound

A supported catalyst of a solid powder was prepared in the same manner as in Preparation Example 1, except that ethylene (bisindenyl) zirconium dichloride (rac-Et (Ind) ₂ ZrCl ₂ ) was used as the second organic transition metal compound. .

Preparation Example 3 Preparation of Catalyst Containing Third Organic Transition Metal Compound

Diphenylmethylidene (normal butylcyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) zirconium dichloride (Ph ₂ C (2,7-t-) as a third organic transition metal compound A supported catalyst of a solid powder was prepared in the same manner as in Preparation Example 1, except that BuFlu)) (nBu-Cp) ZrCl ₂ ) was used.

Experimental Example 1 Evaluation of Properties of Catalysts Prepared in Preparation Examples 1 to 3

The copolymerization method was carried out in a 2 L stainless reactor for slurry high temperature and high pressure reaction, and the supported first to third organic transition metal compound (metallocene) catalysts obtained from Preparation Examples 1 to 3 were charged and triethylaluminum was used as a promoter. Was used. First, an isobutane and a supported metallocene catalyst were charged in a 2 L reactor, and ethylene, hexene-1, and hydrogen were continuously injected to obtain a polyethylene copolymer (ethylene / 1-hexene copolymer). The polymerization experiments of Examples 1 to 3 were intended to compare the density and the melt flow index of the supported metallocene catalysts obtained from Preparation Examples 1 to 3 under the same copolymerization conditions. The polymerization conditions and the results are shown in Table 1 below.

Cat 'code Preparation Example 1 Preparation Example 2 Preparation Example 3 Cocat ' TEA (0.2M) TEA (0.2M) TEA (0.2M) Temp. 90 90 90 Pess. (Psig) 390 390 390 C2- (psig) 160 160 160 H2, g / ton C2 100 100 100 HX-1 (mL) 8 8 8 Run time (min.) 60 60 60 Yield (g) 416 210 368 MIE (dg / min) 19.136 0.380 0.025 Density (g / cc) 0.9545 0.9440 0.9281

The conditions of the second organometallic compound desired in the present invention should have a property of producing a polymer having a median weight average molecular weight and a medium density compared to the polymer polymerized with the first organometallic compound and the third organometallic compound. In order to confirm this, as shown in Table 1, each was compared under the same polymerization conditions, and the desired organometallic compound was found.

Comparative Example 1 Preparation of Catalyst Containing Two Organic Transition Metal Compounds

In a nitrogen atmosphere, bis (isobutylcyclopentadienyl) zirconium dichloride ((iBuCp) ₂ ZrCl ₂ ) as the first organic transition metal compound and diphenylmethylidene (normal butyl) as the second organic transition metal compound were added to the high pressure reactor. Cyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) zirconium dichloride (Ph ₂ C (2,7-t-BuFlu)) (nBu-Cp) ZrCl ₂ ) and methylalumina Noxic acid (MAO, manufactured by Albemarle, 10% toluene solution) was mixed and stirred at 60 ° C. for 60 minutes to prepare a solution. In the solution, calcined silica (SiO ₂ ) at a temperature of 250 ° C. was added to the solution for 1 hour, and then the supernatant was removed. Next, the remaining solid particles were washed twice with hexane, and then dried under vacuum to prepare a supported catalyst of free flowing solid powder.

Example 1 Preparation of Catalysts Containing Three Organic Transition Metal Compounds

In a nitrogen atmosphere, bis (isobutylcyclopentadienyl) zirconium dichloride ((iBuCp) ₂ ZrCl ₂ ) as the first organic transition metal compound and ethylene (bisindenyl) zirconium as the second organic transition metal compound were added to the high pressure reactor. Dichloride (rac-Et (Ind) ₂ ZrCl ₂ ), diphenylmethylidene (normal butylcyclopentadienyl) (2,7-di-tert-butylfluoren-9-yl) as a third organic transition metal compound Zirconium dichloride (Ph ₂ C (2,7-t-BuFlu) (nBu-Cp) ZrCl ₂ ) and methylaluminoxane (MAO, 10% toluene solution from Albemarle) were mixed and 60 min at 60 ° C. Was stirred to prepare a solution. Silica (SiO ₂ ) calcined at 250 ° C. was added to the solution, ultrasonic wave was applied for 1 hour, and the supernatant was removed. Next, the remaining solid particles were washed twice with hexane, and then dried under vacuum to prepare a supported catalyst of free flowing solid powder.

[Examples 2 to 4 and Comparative Example 2] Evaluation of Physical Properties of Ethylene / 1 -hexene Copolymer and Copolymer

Polyethylene was prepared by copolymerizing the catalyst compositions prepared in Example 1 and Comparative Example 1 (Examples 2 to 4 and Comparative Example 2). The copolymerization method was carried out according to the polymerization method of the continuous single loop method well known to partners, and the mixed supported metallocene catalyst obtained from Preparation Example 1 was continuously introduced at a rate of 1.5 g / h into the single loop slurry polymerization process and Polyethylene was prepared using 1-hexene as the monomer. Specifically, the polymerization conditions of polyethylene were firstly filled with isobutane in a 53 L single loop reactor and continuously injected with ethylene, hexene-1 and the catalyst to obtain polyethylene continuously, and the polymerization conditions are shown in Table 2 below. It was.

Polyethylene Example 2 Example 3 Example 4 Comparative Example 2 Utilization catalyst Example 1 Example 1 Example 1 Comparative Example 1 Polymerization temperature (℃) 89 89 89 89 1-hexene (wt%) 1.2 1.2 1.2 1.2 Hydrogen (mg / kgC2) 200 150 100 200 Catalytic activity (gPE / gCat-hr) 3,500 3,400 3,200 3,500

Experimental Example 2 Evaluation of Physical Properties of Commercial Copolymer

The physical properties and moldability of three commercially available polyethylene products (Comparative Examples 3 to 5) were compared under the same conditions as the polyethylenes of Examples 2 to 4 and Comparative Example 2. Comparative Example 3 is a 8,000 M high-density polyethylene product produced by Lotte Chemical, Comparative Example 4 is a HIDEN® P600 high-density polyethylene product produced by Daehan Emulsifier, Comparative Example 5 is Yuzex® 6100 high-density polyethylene produced by SK Chemicals Product. Comparative results of commercially distributed raw materials of Comparative Examples 3 to 5 and the raw material properties of Examples 2 to 4 and Comparative Example 2 are shown in Table 3, the sheet properties in Table 4, pipe properties in Table 5 The extrusion moldability is shown in Table 6 below.

division Item Example 2 Example 3 Example 4 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Resin properties MIP (5Kg), g / 10 min 0.38 0.23 0.19 0.38 0.27 0.21 0.25 SR (F / P) 24.7 25.6 25.1 25.3 22.8 33.2 42.9 Density, g / cm 3 0.9493 0.9486 0.9491 0.9499 0.9467 0.949 0.9483 Molecular weight distribution Bimodal Bimodal Bimodal Bimodal Bimodal Bimodal Bimodal LMW (%) 55.5 56.4 56.9 58.0 - 54.5 59.7 Mw (g / mol) 157,968 187,076 199,521 179,659 261,642 234,315 263,537 Mz (g / mol) 763,876 864,153 941,756 759,359 1,801,018 1,702,804 2,161,748 Mw> 1,000,000 (%) 4.0 5.5 6.6 6.4 9.6 9.0 10.6 Mw> 5,000,000 (%) 0.01 0.02 0.03 0.06 0.62 0.48 0.86 MWD (Mw / Mn) 13.92 11.90 13.52 15.16 16.98 22.63 25.03 Melt Strength (cN) 3.79 3.73 3.22 2.80 0.20 0.76 0.50 Melt tension
(gf, @ 230˚C) 6.01 ND ND 4.43 5.01 4.22 4.5 Shear Thining Index (STI) 21.3 30.5 32 18.7 37.9 44.2 50.7 Modulus Ratio Index (MRI) 167.0 100.4 97.9 164.2 44.2 40.8 30.3 Relaxation Time, τ ₀ (s) 1.85 1.97 1.90 1.66 243.14 65.88 447.05 LCBI 0.07 0.07 0.06 0.11 0.46 0.28 0.65

division Item Example 2 Example 3 Example 4 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Sheet property Yield Point Tensile Strength, kg / ㎠ 265 255 270 277 248 265 253 Elongation,% 776 753 766 770 804 784 754 Flexural modulus, kg / ㎠ 11651 11439 11537 12169 10213 11281 11296 Izod impact strength,
(Notch, room temperature), kgcm / cm 18.8 33.3 32.7 22.0 28.7 23.3 16.9 Izod impact strength, (Notch, -20 ℃), kgcm / cm 10.3 16.8 19.6 13.6 17.8 12.4 8.8

division Item Example 2 Example 3 Example 4 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Pipe property HS (20℃@12.4MPa)
→ ISO standard 100hr or more 209.9 > 332 401 > 255 > 215 > 110 217 HS (80℃@5.4MPa)
→ ISO standard 165hr or more 213 > 1370 > 313 > 215 > 200 > 200 > 200

division Item Example 2 Example 3 Example 4 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Pipe Forming
(200 ℃) Resin Melt Pressure (Bar) 96.7 107.5 106.5 114.6 116.8 114.2 99.7 Ampere (A) 61.7
~ 64.4 64.4
~ 68.0 64.6
~ 68.8 66.5
~ 69.4 67.7
~ 71.5 66.8
~ 70.1 62.1
~ 65.4 Screw speed
(rpm) 64 64 64 64 64 64 64 Motor speed (rpm) 970 970 970 970 970 970 970 Extrusion amount
(g / min) 740.0 766.7 776.7 678.3 748 773 767.7 Extrusion amount / resin melt pressure 7.7 7.1 7.3 5.9 6.4 6.8 7.7 Pipe surface Good Good Good Bad Good Good Good

Experimental Example 3 Forming of Pipe

Pipes of 50 mm, outer diameter 60 mm, thickness 5.5 mm, and approximate inner diameter 49 mm were molded through a pipe extruder using the polymers of Examples 2 to 4 and Comparative Examples 2 to 5 above.

Examples of the polymers of Example 3 and Preparation Example 1 and Comparative Example 5, such as weight average molecular weight, Z average molecular weight, Z + 1 average molecular weight, low molecular weight and melting temperature, etc. The analysis results are shown in Tables 7 and 8 below.

division Pipe extraction location Example 3 Preparation Example 1 Comparative Example 5 Mw Center (A) 204,966 175,441 244,754 Outside (B) 209,657 174,158 225,700 Mz A 1,061,098 913,630 2,358,007 B 1,123,767 908,164 2,036,455 Mz + 1 A 2,065,774 1,733,105 5,729,000 B 2,503,773 1,724,060 4,639,116 LMW% A 58.3 58.7 63.8 B 57.5 60.2 67.0 Mw <10,000,% A 15.5 18.7 23.9 B 14.7 19.5 24.5 Mw> 1,000,000,% A 7.5 5.8 9.7 B 7.7 5.6 8.9 Tm A 130.0 128.0 129.4 B 129.3 128.4 129.7

Classification (Center A → Outside B) Example 3 Preparation Example 1 Comparative Example 5 △ Mw (%) 2.24 -0.74 -8.44 △ Mz (%) 5.58 -0.60 -15.79 △ Mz + 1 (%) 17.49 -0.52 -23.49 △ LMW (%) -1.39 2.49 4.78 △ Mw <10,000 (%) -5.44 4.10 2.45 △ Mw> 1,000,000 (%) 2.60 -3.57 -8.99 △ Tm (%) -0.54 0.31 0.23

2 is GPC data of polyethylene obtained in Examples 2 to 4 and Comparative Examples 2 to 5 of the present invention. As shown in Figure 2, GPC analysis of the polyethylene obtained in Examples 2 to 4 and Comparative Example 2 all showed the form of bimodal, GPC analysis of the commercially available polyethylene of Comparative Example 3 is a monomodal The morphology of the polyethylene of Comparative Examples 4 and 5 shows the bimodal morphology.

As shown in Table 3 and Figure 2, when comparing the weight average molecular weight (Mw) of Examples 2 to 4 and Comparative Example 2 is very low compared to the weight average molecular weight of commercially available Comparative Examples 3 to 5. In general, polyethylene having a high weight average molecular weight is known to have excellent impact strength and long term physical properties in terms of physical properties compared to polyethylene having a relatively low weight average molecular weight. For this reason, in order to increase the physical properties of the product, the weight average molecular weight is usually increased within a range in which the product processability does not decrease. However, as shown in Tables 4 and 5, the polyethylene of Examples 2 to 4 of the present invention has a relatively low weight average molecular weight, but exhibits better impact strength and long-term physical properties.

In addition, in view of molding processability, as shown in Table 3, Example 4 exhibits a very low melt flow index and a melt flow index ratio compared to Comparative Examples 2 to 5. This means that the viscosity in the molten state during the molding process is high, and the viscosity is high even in the processing conditions of high strain rate. However, as shown in Table 6 above, during the pipe forming process in the extruder, it shows lower melt pressure and motor amperage. This is because the weight average molecular weight is relatively low compared to Comparative Examples 3 to 5 shows a lower viscosity in the processing region of high strain rate.

In addition, it is important to prevent sagging during pipe forming. In order to increase such dimensional stability, it is important to increase the melt tension (Melt Tension) and the melt strength (Melt Strength), for this purpose it is generally intended to increase the polymer content of the weight average molecular weight of 1,000,000 g / mol or more. More preferably, the more the ultra-high molecular weight of 10,000,000 g / mol or more weight average molecular weight is less sag. However, when comparing the content of the weight average molecular weight 1,000,000g / mol or more as shown in Table 3 and Figure 2, the contents of Examples 2 to 4 and Comparative Example 2 is very low compared to the contents of Comparative Examples 3 to 5. On the other hand, Figure 3 is a graph showing the molecular weight and the melt strength relationship of the polyethylene obtained in Examples 2 to 4 and Comparative Examples 2 to 5 of the present invention, Figure 4 is Examples 2 to 4 and Comparative Examples 2 to 4 of the present invention 5 is a graph showing the relationship between the pulling speed and the melt strength of the polyethylene obtained in step 5. As shown in Figures 3 and 4, the polymers of Examples 2 to 4 show very high melt tension and melt strength compared to Comparative Examples 3 to 5.

In order to prepare a polymer showing high melt tension and melt strength, there is a method of increasing the polymer content of a weight average molecular weight of 1,000,000 g / mol or more, as mentioned in the above description, and another method is a long chain branch There is a way to increase the number of. However, in order to manufacture products with long-term physical properties such as pipes, it is necessary to minimize long-chain branching that reduces long-term physical properties. Thus, the LCBI (Long Chain Branch Index) values defined in the literature Macromolecules 1999, 32, 8454-8464 are analyzed and shown in Table 3. Comparing the LCBI values of Examples 2-4 with the LCBI values of Comparative Examples 2-5 shows very low values. This has the advantage that the long-term physical properties of the pipe molded body can be more excellently manufactured. And through this, it can be seen that there is little long chain branching, and despite the low weight average molecular weight, it exhibits a high melt tension and melt strength. The reason is judged that the third polymer having an intermediate molecular weight plays a role in suppressing the movement of the polymer chain.

In addition, it is an important factor to prevent the surface melt (Melt Fracture) during the pipe forming. Polymers used in pipes generally exhibit high weight average molecular weights to increase long-term physical properties, and surface roughness may occur during molding because of their high molecular weight and high melt viscosity. POL YMER ENGINEERING AND SCIENCE, JUL Y 2004, Vol. 44, No. As explained in the document of 7, it occurs because relatively low molecular weight polymers move to the outer surface of the pipe by chain migration during molding. Here, in the case of a pipe, it means the central part of the thickness of the pipe, as shown in the definition 1 and FIG. 5. The relatively low molecular weight polymers located on the outer surface have a low modulus of elasticity, which makes it difficult to retain the friction energy generated at the extruder wall, and gives rise to roughness at the surface because it releases energy when discharged from the outside of the extruder. Here, the outer surface means a surface that is in contact with the empty space inside the surface and the surface exposed to the outside. In order to prevent this, it is necessary to suppress a phenomenon in which polymer chains having a relatively low molecular weight move in the outward direction inside the extruder. To this end, in the present invention, a third polymer having a relatively high molecular weight than the low molecular weight polymer and a relatively low molecular weight relative to the high molecular weight polymer was introduced in the bimodal polymer prepared in Comparative Example 2. This was implemented through the second organic transition metal compound described in Example 1. In order to prove the role of the chain transfer inhibition of the third polymer claimed in the present invention, the pipe was molded as in Experimental Example 3, and the sample was taken at the position described in Definition 1 and FIG. Gel permeation chromatography (GPC) and DSC were analyzed to determine the weight average molecular weight and melting temperature (Tm).

As shown in Table 6, the samples taken at the external location (B) of Comparative Example 2 and commercially available Comparative Example 5 having a bimodal form without the third polymer compared to the sample taken at the central location (A) The weight average molecular weight, Z average molecular weight and Z + 1 average molecular weight are low.

In addition, bimodal products have a higher density of polymers having lower molecular weight than those of high molecular weight polymers in terms of processing and polymer properties. Comparing the melting temperature through the DSC analysis of Table 6, the sample taken at the external (B) position of Comparative Examples 2 and 5 has a higher melting temperature than the sample taken at the center (A) position.

The difference in molecular weight and melting temperature at each sampling location means that the relatively short polymer chains move in the extruder in the direction of the wall where the stress (friction energy) is relatively high. This means that the polymer chains with relatively long lengths and high modulus of elasticity (G ') move the chain in the direction of the center of relatively low energy in the extruder for energy balance.

In Example 3 obtained in the present invention, as shown in Tables 7 and 8, the sample taken at the external position (B) has a weight average molecular weight of 2% or more and a Z average molecular weight of 5% compared to the sample taken at the central position (A). Above, it can be seen that the Z + 1 average molecular weight increased by more than 15%. This allows chains with relatively high molecular weights and high modulus of elasticity to be present on the outer surface, while retaining the high friction energy generated at the extruder wall without dissipating when discharged outside the extruder. Through this evaluation, the content claimed in the present invention is that the third polymer inhibits the chain transfer of the first polymer and the second polymer so that no surface framing occurs.

In addition, Example 4 of the present invention in the comparison of the sheet physical properties of Table 4 showed the most excellent results of low temperature and room temperature Izod impact strength.

Although the polymer of Example 4 of the present invention had the lowest melt flow index in Table 6 comparing the pipe formability, the resin melt pressure and motor ampere were 10% lower than those of the polymers of Comparative Examples 2 to 5. By showing the highest extrusion amount, the moldability was excellent. This resulted in high molding results using low energy. In spite of the high formability, the results of the water resistance test physical properties of the pipes, Examples 2 to 4 compared to Comparative Examples 2 to 5 obtained the equivalent or more results. Therefore, the polyethylene of the present invention is superior in formability and appearance while embodying product properties equivalent to those of conventional polyethylene, and has the advantage of increasing productivity of molded products with the same energy consumption.

In addition, the molecular weight distribution obtained from gel permeation chromatography (GPC) for each polyethylene in Examples 2 to 4 and Comparative Examples 2 to 5 is compared and shown in FIG. 2. 3 is a graph showing the molecular weight and melt strength relationship of the polyethylene obtained in Examples 2 to 4 and Comparative Examples 2 to 5 of the present invention, Figure 4 is obtained in Examples 2 to 4 and Comparative Examples 2 to 5 of the present invention This graph shows the relationship between pulling speed and melt strength of polyethylene. As shown in Figures 4 and 5, the polyethylene obtained in Examples 2 to 5 shows a relatively good melting strength, compared to the polyethylene obtained in Comparative Examples 2 to 5, and shows a similar melt strength when the pulling rate is low, As the pulling speed increases, the required force increases, indicating good melt strength. This phenomenon can also be judged as a phenomenon that occurs because the third polymer obtained from the second organometallic compound represented by the formula (2), which is claimed in the present invention, suppresses the chain transfer of the polymers under high stress.

[Definition 1]

In pipes with a standard dimension ratio, SDR = od / en (Standard Dimension Ratio) of 2 to 20,

Where id is the inner diameter, od is the outside diameter, and en is the wall thickness.

Claims (11)

(Iii) at least one first organic transition metal compound represented by the following general formula (1) as a catalyst for forming a low molecular weight polyolefin;
(Ii) at least one second organic transition metal compound represented by the following formula (2) as a catalyst for forming a medium molecular weight polyolefin;
(Iii) at least one third organic transition metal compound represented by the following general formula (3) as a catalyst for forming a high molecular weight polyolefin; And
(Iii) at least one cocatalyst selected from the group consisting of aluminoxanes represented by the following formulas 4 to 6,
The amount of the second organic transition metal compound is 0.5 to 10 moles, and the amount of the third organic transition metal compound is 0.5 to 10 moles, based on 1 mole of the first organic transition metal compound. Catalyst composition.
[Formula 1]
(L ¹ ) (L ² ) (X ¹ ) (X ² ) M ¹
In Formula 1, M ¹ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ¹ ) and (L ² ) are each independently a cyclopentadienyl group including at least one hydrocarbon substituent having 3 to 10 carbon atoms containing at least one secondary or tertiary carbon or at least one substituent containing silicon (Si) Is; (X ¹ ) and (X ² ) are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms.
[Formula 2b]

In Formula 2b, Mb ² is titanium (Ti), zirconium (Zr) or hafnium (Hf); Rb ³ to Rb ⁶ are each independently hydrogen or a hydrocarbon substituent having 1 to 10 carbon atoms; Qb ¹ is hydrogen or a carbon (C) atom, a silicon (Si) atom or a germanium (Ge) atom having a hydrocarbon substituent of 1 to 10 carbon atoms; Xb ³ and Xb ⁴ are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1-6.
[Formula 3]
(L ^5- (Q ² ) nL ⁶ ) (X ⁵ ) (X ⁶ ) M ³
In Formula 3, M ³ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ⁵ ) is a fluorenyl group having two or more hydrocarbon substituents having 4 to 10 carbon atoms containing tertiary carbon; L ⁶ is a cyclopentadienyl group having one or more hydrocarbon substituents of 4 to 10 carbon atoms; (Q ² n) is a crosslinking functional group represented by the formula (Q ² R ³ R ⁴ ) n, wherein Q ² is a carbon atom, a silicon atom or a germanium atom, and R ³ and R ⁴ are independently hydrogen or 1 to 10 carbon atoms A hydrocarbon group of; X ⁵ and X ⁶ are independently F, Cl, Br, I or a hydrocarbon group of 1 to 10 carbon atoms; n is an integer of 1-5.
[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 4, 5 and 6, R 'is a hydrocarbon group, x is an integer of 1 to 70, y is an integer of 3 to 50. The method according to claim 1, wherein (L ¹ ) and (L ² ) are each independently an alkyl group having 3 to 7 carbon atoms or 1 to 10 carbon atoms containing at least one secondary or tertiary carbon, without containing an aryl group It is a cyclopentadienyl group containing at least one trimethylsilyl group unsubstituted or substituted with an alkyl group, a catalyst composition for producing a multimodal polyolefin. delete The method of claim 1, wherein (L ⁵ ) is a fluorenyl group having two alkyl or cycloalkyl groups having 4 to 8 carbon atoms containing tertiary carbon; L ⁶ is a cyclopentadienyl group having one alkyl group having 4 to 10 carbon atoms that does not include an aryl group, the catalyst composition for producing a multimodal polyolefin. The catalyst composition of claim 1, wherein R ³ and R ⁴ are the same aryl group having 6 to 10 carbon atoms. The catalyst composition of claim 1, wherein the first organic transition metal compound is selected from the group represented by the following Chemical Formulas 1a to 1o.

(Formula 1a),

(Formula 1b),

(Formula 1c),

(Formula 1d),

(Formula 1e),

(Formula 1f),

(Formula 1g),

(Formula 1h),

(Formula 1i),

(Formula 1j),

(Formula 1k),

(1 l),

(Formula 1m),

(Formula 1n) and

Formula 1o
In Formulas 1a to 1o, M _a ¹ to M _o ¹ are each independently titanium (Ti), zirconium (Zr), or hafnium (Hf); R _a ¹ To R _o ¹ and R _a ² to R _o ² are each independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; X _a ¹ to X _o ¹ and X _a ² to X _o ² are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n _a ¹ to n _o ¹ and n _a ² to n _o ² are each independently an integer of 0 to 10. delete The catalyst composition of claim 1, wherein the third organic transition metal compound is selected from the group represented by the following Chemical Formulas 3a to 3c.

(Formula 3a),

(Formula 3b) and

Formula 3c
In Chemical Formulas 3a to 3c, M is titanium (Ti), zirconium (Zr) or hafnium (Hf); R ¹ and R ² are independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; R ³ , R ⁴ and R ⁵ are independently hydrogen or a hydrocarbon group having 1 to 10 carbon atoms; Q is a carbon atom, silicon atom or germanium atom; X ¹ and X ² are independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1 to 7. The catalyst composition of claim 1, wherein the first to third organic transition metal compounds and the cocatalyst are supported on an organic or inorganic carrier. (Iii) at least one first organic transition metal compound represented by the following general formula (1) as a catalyst for forming a low molecular weight polyolefin; (Ii) a catalyst for forming a medium molecular weight polyolefin, comprising: at least one second organic transition metal compound represented by Formula 2; (Iii) at least one third organic transition metal compound represented by the following general formula (3) as a catalyst for forming a high molecular weight polyolefin; And (iii) at least one cocatalyst selected from the group consisting of aluminoxanes represented by the following Formulas 4 to 6, wherein the amount of the second organic transition metal compound is used per mole of the first organic transition metal compound A multimodal polyolefin copolymer obtained by polymerizing an olefin monomer in the presence of a catalyst composition of 0.5 to 10 mol and the amount of the third organic transition metal compound is 0.5 to 10 mol.
[Formula 1]
(L ¹ ) (L ² ) (X ¹ ) (X ² ) M ¹
In Formula 1, M ¹ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ¹ ) and (L ² ) are each independently a cyclopentadienyl group including at least one hydrocarbon substituent having 3 to 10 carbon atoms containing at least one secondary or tertiary carbon or at least one substituent containing silicon (Si) Is; (X ¹ ) and (X ² ) are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms.
[Formula 2b]

In Formula 2b, Mb ² is titanium (Ti), zirconium (Zr) or hafnium (Hf); Rb ³ to Rb ⁶ are each independently hydrogen or a hydrocarbon substituent having 1 to 10 carbon atoms; Qb ¹ is hydrogen or a carbon (C) atom, a silicon (Si) atom or a germanium (Ge) atom having a hydrocarbon substituent of 1 to 10 carbon atoms; Xb ³ and Xb ⁴ are each independently F, Cl, Br, I or a hydrocarbon group having 1 to 10 carbon atoms; n is an integer of 1-6.
[Formula 3]
(L ^5- (Q ² ) nL ⁶ ) (X ⁵ ) (X ⁶ ) M ³
In Formula 3, M ³ is titanium (Ti), zirconium (Zr) or hafnium (Hf); (L ⁵ ) is a fluorenyl group having two or more hydrocarbon substituents having 4 to 10 carbon atoms containing tertiary carbon; L ⁶ is a cyclopentadienyl group having one or more hydrocarbon substituents of 4 to 10 carbon atoms; (Q ² n) is a crosslinking functional group represented by the formula (Q ² R ³ R ⁴ ) n, wherein Q ² is a carbon atom, a silicon atom or a germanium atom, and R ³ and R ⁴ are independently hydrogen or 1 to 10 carbon atoms A hydrocarbon group of; X ⁵ and X ⁶ are independently F, Cl, Br, I or a hydrocarbon group of 1 to 10 carbon atoms; n is an integer of 1-5.
[Formula 4]

[Formula 5]

[Formula 6]

In Formulas 4, 5 and 6, R 'is a hydrocarbon group, x is an integer of 1 to 70, y is an integer of 3 to 50. The melt load ratio (SR = MIF / MIP, MIF is a high load melt flow index measured according to ASTM D1238 at 21.6 kg / 10 min and 190 ° C., and MIP is 5.0 kg / 10 min and 190 ° C. Is a melt flow index measured according to ASTM D1238) is 20 to 200, multi-modal polyolefin copolymer.

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