KR20190063794A - Polyolefin composition having imporoved stress resistance - Google Patents

Abstract

The present invention relates to a polyolefin composition with improved stress resistance, which is prepared by mixing two polyolefins prepared by using a metallocene supported catalyst, and has 0.6 to 1.6 of a tensile stress gradient (slope) in a tensile strength test in accordance with ASTM D638 standard.

Description

[0001] POLYOLEFIN COMPOSITION HAVING IMPOROVED STRESS RESISTANCE [0002]

The present invention relates to a polyolefin composition prepared using a metallocene supported catalyst supported with one kind of metallocene catalyst compound. More particularly, the present invention relates to a polyolefin composition obtained by mixing two kinds of polyolefins prepared using a metallocene supported catalyst supported with one kind of metallocene catalyst compound in various ratios, wherein the polyolefin composition is improved Stress resistance.

In the case of blow molded containers made of polyolefin, caps and pipe products made of plastic bottles, mechanical properties and environmental resistance are required. These physical properties are influenced by various factors such as molecular weight distribution, length and number of carbon chains, and the larger the molecular weight, the broader the molecular weight distribution, and the longer the carbon chain, the higher the physical properties of the polyolefin product. In order to improve the durability of the final product, the properties are controlled. The durability of the final product should be one year for durability and 50 years for the pipe for boiler heating pipe. In actuality, it is not possible to evaluate the equivalent time for product development, and the environmental stress cracking property is easily understood for the durability evaluation. However, this evaluation also takes several hours to one year, It is difficult to reflect the physical properties of the actual polyolefin.

Since the durability of the polyolefin structure is influenced by various factors, the tendency of the physical property evaluation results is not shown by one parameter. This difference in properties is caused by the difference in the catalysts and processes for producing polyolefins. The metallocene catalysts using a Group 4 transition metal have a single active site as compared with the conventional Ziegler-Natta catalysts, It is easy to control the molecular weight and molecular weight distribution of polyolefin and the like, and it is possible to control the distribution of comonomers such as? -Olefins and the like, and thus it has been used as a technique for simultaneously improving workability and mechanical properties.

However, the polyolefin prepared by using the metallocene catalyst has a problem in that the molecular weight distribution is narrower than that of the conventional Ziegler-Natta catalyst, and thus there is a limit to improvement in processability.

Various methods have been attempted to obtain a polyolefin having a broad molecular weight distribution using a metallocene catalyst. For example, there are (1) a method of improving the processability by blending polyolefins having different molecular weights (U.S. Patent No. 4,461,873), (2) a method in which two or more metallocene compounds having different molecular weights are used in a single reactor, (US Pat. No. 4,530,914); and (3) a method of broadening the molecular weight distribution by changing the reaction conditions of three or more reactors (US Patent Publication No. 2015-0166697).

However, the blending method such as (1) generally has a high gel content, resulting in poor product appearance, difficulty in producing a product having uniform physical properties, and high manufacturing cost. The method using two or more kinds of metallocene catalysts such as (2) may be inferior in the form of the resulting polymer, and it is difficult to ensure that two or more kinds of catalysts produce a polyolefin having homogeneous physical properties. When controlling the physical properties using two or more metallocene compounds as in (2), the metallocene compound reacts sensitively with hydrogen or a comonomer, and the reactivity of the two compounds is changed according to the reaction conditions, There is a difficulty in producing a polyolefin having a polyolefin. (3), there is a problem that the efficiency of the reactor is lowered due to the different reaction conditions or the production cost is high.

Korean Patent No. 10-1132180 relates to a method for producing polyethylene having bimodal molecular weight distribution using two kinds of organometallic compounds, wherein the ratio of the two kinds of organometallic compounds is varied to adjust molecular weight and molecular weight distribution Technology. This method is a technique for producing polyethylene having a broad molecular weight distribution, but has a problem in that the physical properties and processability of the polymer are deteriorated because the range of controlled molecular weight distribution is very wide. Korean Patent No. 10-1592436 also discloses the preparation of polyolefins which exhibit excellent physical properties as having a large molecular weight, a broad molecular weight distribution and a high LCB (long chain branch). This patent describes a method for producing polyethylene having a broad molecular weight distribution using two or more organometallic compounds, but the polyethylene produced by the described method is not very excellent in environmental stress cracking resistance.

However, polymers produced in reactors using the same or different reaction conditions using one kind of catalyst have a certain tendency of reactivity depending on the reaction conditions, so that it is easy to control the reaction conditions. The polyolefin product produced by this method can easily control the physical properties of the polyolefin product and can produce a product having excellent physical properties.

U.S. Patent Publication No. 4,461,873 (July 24, 1984) U.S. Patent Publication No. 4,530,914 (July 23, 1985) U.S. Published Patent Application No. 2015-0166697 (June 2015) Korean Patent No. 10-1132180 (March 26, 2012) Korean Patent No. 10-1592436 (2016.02.01)

The object of the present invention is to provide a polyolefin having excellent mechanical and chemical resistance in order to solve the problems of the prior art.

In order to accomplish the above object, the present invention provides a polyethylene composition prepared by mixing two kinds of polyolefins prepared using a metallocene supported catalyst supported with one kind of metallocene catalyst compound.

Specifically, the present invention relates to a polyolefin composition obtained by mixing two kinds of polyolefins prepared using a metallocene supported catalyst, wherein the elongation length in the region where the specimen length is increased by 6 to 12 times in the tensile strength test according to the ASTM D638 standard (Slope) of a tensile stress according to a tensile stress of 0.6 to 1.6.

The polyolefin composition of the present invention has a high degree of change in tensile stress (slope) and a large crystal area, and thus has high mechanical and chemical properties and moldability because of its high stress resistance.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a graph of the tensile stress (slope) of polyethylene according to examples and comparative examples of the present invention
FIG. 2 is a graph drawn by adjusting the viewpoint of the strain hardening region, which is a region where the degree of change (slope) of the tensile stress in FIG. 1 is rapidly increased, to (0.0).

In the case of conventional polyolefins made by the method of producing polyolefins by carrying two or more kinds of catalyst compounds on one carrier, the reactivity of hydrogen and comonomer of two or more kinds of catalyst compounds varies depending on the change of the reaction conditions, It is not easy to control physical properties.

Thus, the present invention is a result of the in-situ blend product prepared by preparing each polyolefin having different physical properties by using a supported metallocene catalyst having a single catalyst compound and then mixing them at various mixing ratios.

A polyolefin composition having various physical properties can be obtained by mixing (1) a low molecular weight polyolefin prepared using a single catalyst compound and (2) a high molecular weight polyolefin in various ratios, and the molecular weight distribution and the comonomer Distribution and content can be controlled. According to the present invention, polyolefins having excellent mechanical and chemical resistance can be obtained by preparing two kinds of polyolefins under appropriate reaction conditions and then mixing them.

The excellent mechanical and chemical properties of polyolefins indicate that they are highly resistant to destruction of polyolefins, and that they are less deformed depending on a given force, or that they require a great resistance to failure. Basically, when the crystallinity is high, the strain against the stress is small, and on the contrary, the polyolefin easily breaks down because the force to break is small. In order to increase both the strain amount and the fracture stress limit, the molecular weight distribution can be broadened and the properties of the polyolefin can be improved by raising the ratio of the amorphous region to the high molecular weight. As the molecular weight increases, the entanglement of the polymer chains increases, resistance to tensile force increases, and amorphous regions having a high molecular weight are increased, thereby widening the area of the crystals, increasing the intergranular bonds and increasing the resistance to fracture. However, in molded containers such as molded containers, caps and pipes of plastic bottles which need to be firmly supported, there is a negative effect of decreasing the rigidity of the product by decreasing the density as the amorphous region increases. Thus, in order to have both tensile stress and resistance to fracture at high density, the polyolefin composition having a high molecular weight portion containing a high amorphous region and a low molecular weight portion having a high density is widened by widening the molecular weight distribution.

When a small force is applied to the polyolefin, deformation occurs in the elastic region which returns to its original position when the force is removed. When the force is applied, deformation in the plastic region which does not return to the original state . Then, as more and more force is applied, the polyolefin cracks and eventually the polyolefin is destroyed. The strain hardening region is called the strain hardening region, and the larger the stress change depending on the strain in this region, the higher the resistance to the stress of the polyolefin is, so the polyolefin is not broken well. The greater the slope of the strain hardening region of the polyolefin, the higher the resistance to fracture and the higher the environmental stress cracking resistance. The slope of the polyolefin in the corresponding region is 0.2 or more, and the slope of the polyolefin having excellent physical properties is 0.6 or more. For polyolefins with better physical properties, the slope is found to be greater than or equal to 0.7, more preferably greater than or equal to 0.8, and more preferably greater than 0.9.

The larger the crystalline area of the polyolefin, the greater the degree of entanglement of the polymer chains increases the resistance to fracture. The crystalline area of the polyolefin can be calculated from Equation 1 and Equation 2 below, which is described in Joy J. Cheng 2008). Mechanical and Chemical Properties of High Density Polyethylene: Effects of Microstructure on Creep Characteristics. UWSpace. http://hdl.handle.net/10012/4121, the entire contents of which are incorporated herein by reference:

[Formula 1]

Determining an area ^{(lamellar area) (m 2 /} mol) = [ Specific volume of the crystals (specific volume of crystal) (m 3 / kg)] × [ the molecular weight of the crystals (molecular weight of crystal) (kg / mol)] / [ The thickness of the crystal (lamellar thickness) (m)]

In the above equation 1, the lamellar thickness (m) is calculated using the following Gibbs-Thomson equation:

[Formula 2]

^{_{T m = T m 0 * (}} 1- 2σ e / Δh m * L)

(T _m: melting point of the polyolefin in the DSC curve peak, T _m ^0: equilibrium melting point of 415 (K) (infinite crystal _{(infinite crystal)), σ e} : 60.9 × 10 -3 (Jm -2) ( basal (basal plane) surface free energy), Δh _m ^{of: 2.88 × 10 8 (Jm -3} ) ( melt enthalpy per unit area), L: thickness of the crystal)

The polyolefin having high mechanical and chemical resistance may have a crystal area of 0.1 × 10 ⁹ to 50 × 10 ⁹ m ² / mol, for example, 1 × 10 ⁹ to 40 × 10 ⁹ m ² / mol. Alternatively, the crystallite area may be from 3 × 10 ⁹ to 30 × 10 ⁹ m ² / mol, for example from 4 × 10 ⁹ to 20 × 10 ⁹ m ² / mol.

The polyolefin composition of the present invention exhibits excellent physical properties because many chains of polymer chains are entangled and the number of chains that prevent the crystal portion from being destroyed due to high numerical value of crystal area is generated.

In the case of the in-situ blend polyolefin of the present invention, the crystalline area value was higher than that of the single polyolefin, and the mechanical and environmental properties were higher in proportion thereto.

According to one embodiment,

A polyolefin composition obtained by mixing two kinds of polyolefins prepared using a metallocene supported catalyst,

Wherein the polyolefin composition has a tensile stress change (slope) of 0.6 to 1.6 according to an elongated length in a region where the specimen length is increased by 6 to 12 times in the tensile strength test according to the ASTM D638 standard.

In one embodiment the polyolefin compositions of the invention determine the area to be defined by the following equation 1 (lamellar area) is 4 × 10 ⁹ to ^{20 × 10 9 m 2 / mol} :

[Formula 1]

Determining an area ^{(lamellar area) (m 2 /} mol) = [ Specific volume of the crystals (specific volume of crystal) (m 3 / kg)] × [ the molecular weight of the crystals (molecular weight of crystal) (kg / mol)] / [ The thickness of the crystal (lamellar thickness) (m)]

In the above equation 1, the lamellar thickness (m) is calculated using the following Gibbs-Thomson equation:

[Formula 2]

^{_{T m = T m 0 * (}} 1- 2σ e / Δh m * L)

(T _m: melting point of the polyolefin in the DSC curve peak, T _m ^0: equilibrium melting point of 415 (K) (infinite crystal _{(infinite crystal)), σ e} : 60.9 × 10 -3 (Jm -2) ( basal (basal plane) surface free energy), Δh _m ^{of: 2.88 × 10 8 (Jm -3} ) ( melt enthalpy per unit area), L: thickness of the crystal)

In one embodiment, the polyolefin composition of the present invention has a crystallinity of 30 to 90%, a density of 0.910 to 0.980 g / ml, a high load melt index (HLMI) (measured at 190 占 폚 under a load of 21.6 kg) 10 to 200 g / 10 min.

In one embodiment, the polyolefin composition of the present invention comprises a polyolefin having a melt index (MI) (measured at 190 占 폚 under a load of 2.16 kg) of 20 to 120 g / 10 min and a melt index (MI) Is from 0.001 to 3 g / 10 min in a weight ratio of 30 to 70: 70 to 30.

In one embodiment, the polyolefin composition of the present invention has a degree of change (slope) of tensile stress of 0.9 to 1.5 and a degree of crystallinity of 60 to 80%.

In one embodiment, the polyolefin is a (C ₂ -C ₂₀ ) olefin; (C ₄ -C ₂₀ ) diolefins; (C ₃ -C ₂₀ ) cycloolefins; (C ₃ -C ₂₀ ) cyclodiolefins; And substituted or unsubstituted styrenes, and the substituent of the styrene is a (C ₁ -C ₁₀ ) alkyl group, a (C ₁ -C ₁₀ ) alkoxy group, a halogen group , An amine group, a silyl group, and a halogenated (C ₁ -C ₁₀ ) alkyl group.

In one embodiment, the (C ₂ -C ₂₀ ) olefin is selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, 1-hexene ) Or 1-octene (1-octene); The (C ₄ -C ₂₀ ) diolefin may be 1,3-butadiene, 1,4-pentadiene or 2-methyl-1,3-butadiene, methyl-1,3-butadiene); The (C ₃ -C ₂₀ ) cycloolefin may be selected from the group consisting of cyclopentene, cyclohexene, cyclopentadiene, cyclohexadiene, norbonene or methyl- methyl-2-norbonene.

In one embodiment, the metallocene compound included in the metallocene supported catalyst of the present invention may be represented by the following formula (1) or (2), but is not limited thereto:

[Chemical Formula 1]

(2)

In the above formulas (1) and (2)

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

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

n is an integer of 1 to 5,

Ar ¹ and Ar ² may be the same or different and are each independently a ligand having a cyclopentadienyl skeleton, Ar ¹ and Ar ² are each independently selected from the group consisting of a halogen group, a (C ₁ -C ₂₀ ) ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, ( C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl silyl group and a silyl group (C ₆ ~ C ₂₀₎ are each substituted independently by one or more substituents selected from the group consisting of an aryl group, the substituents may bond to one another to form a ring,

B is a component for ligating the ligands Ar ¹ and Ar ² without directly coordinating to the transition metal M and is a group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N) Including the selected element,

L is hydrogen, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀ ) aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl silyl group, and Silyl (C ₆ -C ₂₀ ) aryl group,

m varies depending on the kind of B, and is 1 or 2.

Referred to as the formula ratio of the metallocene catalyst compound to replace metal-free is L _m B ligand catalyst in 1 above, is L _m B ligand exists is referred to as metallocene catalyst compound with a catalyst for bonding the Ar ¹ and Ar ² functional groups of a cross-linked metal. Both of these metallocene compounds can produce polyolefins having excellent mechanical and environmental properties, and when crosslinked metallocene catalyst compounds are used, polyolefins having relatively good physical properties can be produced.

In one embodiment, the metallocene supported catalyst of the present invention comprises a cocatalyst compound selected from the group consisting of compounds represented by the following formulas (3) to (5):

(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the above formulas (3) to (5)

Y ¹ is a (C ₁ -C ₁₀ ) alkyl group,

q is an integer of 1 to 70,

Y ² to Y ⁴ are the same or different, (C ₁ ~ C ₁₀₎ alkyl, (C ₁ ~ C ₁₀₎ alkoxy group and is independently selected from the group consisting of halogen, just one of Y ² to Y ⁴ Is a (C ₁ -C ₁₀ ) alkyl group,

C is a hydrogen ion-binding cation of Lewis base, or a metal or non-metal compound having oxidizing power,

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

In one embodiment, the metallocene compound included in the metallocene supported catalyst of the present invention may be represented by the following formula (1) or (2):

[Chemical Formula 1]

(2)

In the above formulas (1) and (2)

M is zirconium or hafnium,

X is a halogen group,

n is 2,

Ar ¹ and Ar ² are the same or different and are each independently cyclopentadienyl, indenyl or fluorenyl, Ar ¹ and Ar ² are each independently selected from the group consisting of a halogen atom, a (C ₁ -C ₂₀ ) (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl group (C ₆ -C ₂₀ ) aryl (C ₁ -C ₂₀ ) alkyl, (C ₁ -C ₂₀ ) alkyl (C ₆ -C ₂₀ ) aryl, (C ₆ -C ₂₀ ) arylsilyl and silyl ₆ to C ₂₀ ) aryl groups, and the substituents may be bonded to each other to form a ring,

B is (C ₁ -C ₆ ) alkylene,

L is hydrogen or a (C ₁ -C ₂₀ ) alkyl group,

m is 1 or 2;

In one embodiment, the compound represented by Formula 3 is specifically a compound selected from the group consisting of methylaluminoxane, ethylaluminoxane, butylaluminoxane, hexylaluminoxane, octylaluminoxane, Decylaluminoxane, and the like.

In one embodiment, the compound represented by Formula 4 is specifically a compound selected from the group consisting of trimethylaluminum, triethylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminium, for example, trioctylaluminum, tridecylaluminum, dimethylaluminum methoxide, diethylaluminum methoxide, dibutylaluminum methoxide, dimethylaluminum, and the like. The catalyst is preferably selected from the group consisting of chloride, diethylaluminum chloride, dibutylaluminum chloride, methylaluminum dimethoxide, ethylaluminum dimethoxide, Butylaluminum dimethoxide, methylaluminum < RTI ID = 0.0 > dichloride, ethylaluminum dichloride, butylaluminum dichloride, and the like.

In one embodiment, the compound represented by Formula 5 is specifically exemplified by triphenylcarbenium tetrakis (pentafluorophenyl) borate, trimethylammonium tetraphenylborate, triethyl Triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tributylammonium tetraphenylborate, trimethylammonium tetrakis (pentafluorophenyl) borate, trimethylammonium tetrakis (pentafluorophenyl) borate, , Triethylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (pentafluorophenyl) borate, tripropylammonium tetrakis (pentafluorophenyl) borate, tributylammonium tetra Anilinium tetrakis (pentafluorophenyl) borate, anilinium tetraphenylborate, anilinium tetrakis (pentafluorophenyl) borate, N, N (pentafluorophenyl) borate, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, pyridinium tetraphenylborate, pyridinium tetrakis (pentafluorophenyl) borate, pyridinium tetrakis (pentafluorophenyl) (pentafluorophenyl) borate, ferrocenium tetrakis (pentafluorophenyl) borate, silver tetraphenylborate, silver tetrakis (pentafluorophenyl) borate, ) borate, tris (pentafluorophenyl) borane, tris (2,3,5,6-tetrafluoro Tris (2,3,5,6-tetrafluorophenyl) borane, tris (2,3,4,5-tetraphenylphenyl) borane, ), Tris (3,4,5-trifluorophenyl) borane, and the like.

In one embodiment, the carrier included in the metallocene supported catalyst of the present invention is not particularly limited as long as it is a porous organic / inorganic compound having fine pores on the surface or inside thereof. Specifically, the carrier may be an organic compound such as starch, cyclodextrin, or synthetic polymer; Or an inorganic material selected from the group consisting of silica, alumina, magnesium chloride, calcium chloride, bauxite, zeolite, magnesium oxide, zirconium oxide, titanium oxide, boron trioxide, calcium oxide, zinc oxide, barium oxide, thorium oxide, Compounds may be used. Examples of the composite include SiO ₂ -MgO, SiO ₂ -Al ₂ O ₃ , SiO ₂ -TiO ₂ , SiO ₂ -V ₂ O ₅ , SiO ₂ -Cr ₂ O ₃ , SiO ₂ -TiO ₂ -MgO, .

In one embodiment, the content of the metallocene compound, cocatalyst and carrier, based on the total weight of the metallocene supported catalyst, may be from 0.1 to 1.0 wt%, from 10 to 50 wt% and from 60 to 90 wt%, respectively have.

The method of supporting the metallocene compound and the co-catalyst compound on such a support is not particularly limited, but a method of directly supporting the metallocene compound on the carrier from which moisture has been removed; A method of pretreating the support with a promoter compound and then supporting the metallocene compound; A method in which a metallocene compound is supported on a support and then the support is treated with a promoter compound; And a method in which a metallocene compound is reacted with a cocatalyst compound and then supported on a carrier. The temperature at which the metallocene compound and the co-catalyst compound are supported on the support is not particularly limited, but may be -20 캜 to 120 캜 or 0 캜 to 100 캜, considering the efficiency of the supporting process.

Further, when the carrier is supported with the metallocene compound and the co-catalyst compound, a hydrocarbon solvent may be used. Examples of the hydrocarbon solvent include, but are not limited to, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane dodecane), and other aliphatic hydrocarbon solvents; Aromatic hydrocarbon solvents such as benzene, monochlorobenzene, dichlorobenzene, trichlorobenzene, and toluene; Halogenated aliphatic hydrocarbon solvents such as dichloromethane, trichloromethane, dichloroethane and trichloroethane; Or a mixture thereof.

In the present invention, the polyolefin may be produced by polymerization or copolymerization of an olefin-based monomer.

The monomers and comonomers used in the production of the polyolefin may be the same or different and are not particularly limited, but ethylene, propylene, 1-butene, 1-pentene, (C ₂ -C ₂₀ ) olefins such as 1-hexene, 1-octene and the like; 1,3-butadiene, 1,4-pentadiene, and 2-methyl-1,3-butadiene. C ₄ to C ₂₀ ) diolefins; (C ₃ ) such as cyclopentene, cyclohexene, cyclopentadiene, cyclohexadiene, norbonene, methyl-2-norbonene and the like. To C ₂₀ ) cycloolefins; (C ₃ -C ₂₀ ) cyclodiolefins; And substituted or unsubstituted styrene. The substituent of the styrene may be selected from the group consisting of a (C ₁ -C ₁₀ ) alkyl group, a (C ₁ -C ₁₀ ) alkoxy group, a halogen group, an amine group, a silyl group, And halogenated (C ₁ -C ₁₀ ) alkyl groups.

In one embodiment, the monomer used in the preparation of the polyolefin of the present invention is ethylene and the comonomer is at least one selected from propylene, 1-butene, 1-hexene, 1-octene and 1-decene. In one embodiment, the content of comonomer is 0.1 to 20% by weight, based on the weight of the polyolefin produced.

In the present invention, the production of the polyolefin can be carried out by a gas phase process of an olefin, a slurry process, a slurry loop process or a solution process.

Hereinafter, the functions and effects of the present invention will be described in more detail with reference to specific examples of the present invention. It should be understood, however, that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Example

Synthesis of supported catalyst

All synthetic reactions were conducted in an inert atmosphere such as nitrogen (N ₂ ) or argon (Ar), using standard Schlenk technology and glove box technology.

The anhydrous grade of toluene was purchased from Sigma-Aldrich and then passed through activated molecular sieve (4 Å) or activated alumina layer before use. MAO (methylaluminoxane) was purchased from Albemarle 10% toluene solution (HS-MAO-10%). The silica and metallocene catalyst compounds were further processed (refined) by GRACE DAVISON and STREM, .

Supported Catalyst Synthesis Example

In a glove box, silica (10 g) was put in a 0.25 L round bottom flask and taken out of the glove box, and then toluene (0.05 L) was added to prepare silica in a slurry state. The amount of MAO described in the following examples and comparative examples was slowly added to the prepared slurry silica, and then the mixture was stirred at 70 ° C for 1 hour.

In a glove box, the metallocene catalyst compounds described in the following Examples and Comparative Examples were put in a 0.25 L round bottom flask and taken out of the glove box. Then, toluene (0.05 L) was added to dissolve the slurry and the slurry was mixed with the silica and MAO I went slowly. Then, the mixture was stirred at 50 DEG C for 1 hour, cooled to room temperature, and the toluene supernatant was separated and removed. Thereafter, the catalyst was washed with toluene (0.05 L) and n-hexane (0.05 L), and vacuum dried to synthesize a supported catalyst in the form of a free flowing powder.

Example 1

rac-ethylene bistetrahydroindenyl zirconium dichloride Catalyst compound (0.4 g), MAO (77 ml) and silica (10 g) were used to prepare a metallocene supported catalyst according to the supported catalyst synthesis example.

The first polyethylene and the second polyethylene were produced in a continuous slurry loop process at a reactor pressure of 42 kg / cm 2 and a reactor temperature of 70 ° C, maintaining an ethylene injection rate of 33 kg per hour.

The melt index (MI) (measured at 190 占 폚 under a load of 2.16 kg) of the first polyethylene was 22 g / 10 min and the MI (190 占 폚, measured at a load of 2.16 kg) of the second polyethylene was 0.01 g / 10 min. The polyethylene of Example 1 was prepared by mixing the first polyethylene and the second polyethylene at a weight ratio of 50:50.

Example 2

The same metallocene supported catalyst as in Example 1 was synthesized to prepare a polyolefin. The first polyethylene was produced at a reactor pressure of 42 kg / cm 2 at a reactor temperature of 85 ° C while the second polyethylene was produced at a reactor pressure of 42 kg / cm 2 at a reactor temperature of 70 ° C.

The MI of the first polyethylene (measured at 190 占 폚 under a load of 2.16 kg) was 110 g / 10 min and the MI of the second polyethylene (measured at 190 占 폚 under a load of 2.16 kg) was 0.005 g / 10 min. The polyethylene of Example 2 was prepared by mixing the first polyethylene and the second polyethylene at a weight ratio of 55:45.

Example 3

A supported metallocene catalyst was prepared in the same manner as in Example 1, except that 0.35 g of bis (n-butylcyclopentadienyl) zirconium dichloride was used as a catalyst compound, The first polyethylene and the second polyethylene were prepared in the process.

The MI of the first polyethylene (measured at 190 占 폚 under a load of 2.16 kg) was 30 g / 10 min and the MI of the second polyethylene (measured at 190 占 폚 under a load of 2.16 kg) was 2 g / 10 min. The polyethylene of Example 3 was prepared by mixing the first polyethylene and the second polyethylene at a weight ratio of 47: 53.

Example 4

The same metallocene supported catalyst as in Example 3 was synthesized to prepare a polyolefin.

The first polyethylene and the second polyethylene were produced in a continuous slurry loop process at a reactor pressure of 42 kg / cm 2 and a reactor temperature of 85 ° C, maintaining an ethylene injection rate of 33 kg per hour.

The MI (190 占 폚, measured at a load of 2.16 kg) of the first polyethylene produced was 30 g / 10 min and the MI (190 占 폚, measured at a load of 2.16 kg) of the second polyethylene was 0.8 g / 10 min. The polyethylene of Example 4 was prepared by mixing the first polyethylene and the second polyethylene at a weight ratio of 58:42.

Comparative Example 1

Using the same metallocene supported catalyst as in Example 2, except for the continuous process of Example 1, only one kind of polyethylene was produced through the same manufacturing process as that of Example 1. The MI of the produced polyethylene (measured at 190 占 폚 under a load of 2.16 kg) was 7.1 g / 10 min.

Property evaluation

The HLMI (high load melt index) was measured at 190 ° C under a load of 21.6 kg according to ASTM D1238 in order to determine the degree of flow of the polyethylene produced in the above Examples and Comparative Examples. The IZOD impact strength was measured at 25 캜 and -10 캜 according to ASTM D256. The environmental stress cracking resistance was measured according to ASTM D1693 when 50% of the specimens were destroyed.

Example 1 Example 2 Example 3 Example 4 Comparative Example 1 HLMI (g / 10 min) 12 10.6 110 143 140 Density (g / ml) 0.955 0.937 0.957 0.953 0.958 Molecular weight distribution 4.24 12.7 2.75 2.75 2.27 Melting point (℃) 131 124 131 132 133 Crystallinity (%) 63 39 69 68 74 Comonomer content (%) 0.62 3.1 0.64 0.5 0 Crystal area
(m ² / mol) 10 × 10 ⁹ 9.10 × 10 ⁹ 7.71 × 10 ⁹ 7.35 × 10 ⁹ 4.34 × 10 ⁹ The slope in the strain hardening region 1.41 1.12 1.29 1.20 0.52 Impact strength at room temperature 10.9 - 11.8 6.6 8.1 Low temperature impact strength 7.6 - 6.9 5.5 7.8 Environmental stress cracking (hr) > 8,760 > 500 8 6 1.5

Table 1 shows that the same or similar Polyethylene produced continuously in two reactors of different reaction conditions and then mixed with each other (Examples 1 to 4) had a crystallite area (area) of 1 in comparison with one kind of polyethylene (Comparative Example 1) produced under the same conditions as in Example 1 , The slope in the strain hardening region and the environmental stress cracking property are both high, so that it can be confirmed that the stress resistance is high.

2, which is a graph drawn by adjusting the viewpoint of the strain hardening region, which is a region where the degree of change (slope) of the tensile stress of the polyethylene according to Examples and Comparative Examples of the present invention is sharply increased, to (0.0) It can be seen that the mixed polyethylene according to the embodiment of the present invention has higher stress resistance than the single polyethylene of the comparative example considering that the resistance to fracture increases as the slope in the hardened region increases and the environmental stress cracking property increases .

While the present invention has been particularly shown and described with reference to specific embodiments thereof, those skilled in the art will appreciate that such specific embodiments are merely preferred embodiments and that the scope of the present invention is not limited thereby. something to do. Accordingly, the actual scope of the present invention will be defined by the appended claims and their equivalents.

Claims (12)

A polyolefin composition obtained by mixing two kinds of polyolefins prepared using a metallocene supported catalyst,
Wherein said polyolefin composition has a tensile stress change (slope) of 0.6 to 1.6 according to an elongated length in a region where a specimen length is increased by 6 to 12 times in a tensile strength test according to ASTM D638. The polyolefin composition according to claim 1, wherein the polyolefin composition has a lamellar area defined by the following formula 1: 4 x 10 ⁹ to 20 x 10 ⁹ m ² / mol.
[Formula 1]
Determining an area ^{(lamellar area) (m 2 /} mol) = [ Specific volume of the crystals (specific volume of crystal) (m 3 / kg)] × [ the molecular weight of the crystals (molecular weight of crystal) (kg / mol)] / [ The thickness of the crystal (lamellar thickness) (m)]
In the above equation 1, the lamellar thickness (m) is calculated using the following Gibbs-Thomson equation:
[Formula 2]
^{_{T m = T m 0 * (}} 1- 2σ e / Δh m * L)
(T _m: melting point of the polyolefin in the DSC curve peak, T _m ^0: equilibrium melting point of 415 (K) (infinite crystal _{(infinite crystal)), σ e} : 60.9 × 10 -3 (Jm -2) ( basal (basal plane) surface free energy), Δh _m ^{of: 2.88 × 10 8 (Jm -3} ) ( melt enthalpy per unit area), L: thickness of the crystal) The polyolefin composition according to claim 1, wherein the polyolefin composition has a crystallinity of 30 to 90%, a density of 0.910 to 0.980 g / ml, a high load melt index (HLMI) (measured at 190 占 폚 under a load of 21.6 kg) To 200 g / 10 min. The polyolefin composition according to claim 1, wherein the polyolefin composition has a melt index (MI) (190 占 폚, load of 2.16 kg at a temperature of 190 占 폚 under a load of 2.16 kg) and a polyolefin having a melt index Measured in the range of 0.001 to 3 g / 10 min is mixed at a weight ratio of 30 to 70: 70 to 30. The composition of claim 1, wherein the polyolefin is selected from the group consisting of (C ₂ -C ₂₀ ) olefins; (C ₄ -C ₂₀ ) diolefins; (C ₃ -C ₂₀ ) cycloolefins; (C ₃ -C ₂₀ ) cyclodiolefins; And substituted or unsubstituted styrenes, and the substituent of the styrene is a (C ₁ -C ₁₀ ) alkyl group, a (C ₁ -C ₁₀ ) alkoxy group, a halogen group , An amine group, a silyl group, and a halogenated (C ₁ -C ₁₀ ) alkyl group. The method of claim 5, wherein the (C ₂ -C ₂₀ ) olefin is selected from the group consisting of ethylene, propylene, 1-butene, 1-pentene, hexene) or 1-octene; When the (C ₄ -C ₂₀ ) diolefin is 1,3-butadiene, 1,4-pentadiene or 2-methyl-1,3-butadiene, methyl-1,3-butadiene); The (C ₃ -C ₂₀ ) cycloolefin is selected from the group consisting of cyclopentene, cyclohexene, cyclopentadiene, cyclohexadiene, norbonene or methyl-2-norbornene methyl-2-norbonene. < / RTI > The polyolefin composition according to claim 1, wherein the metallocene supported catalyst comprises a metallocene compound represented by the following general formula (1) or (2)
[Chemical Formula 1]

(2)

In the above formulas (1) and (2)
M is selected from the group consisting of Group 3 to Group 10 elements on the periodic table,
X is a halogen group, an amine group, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ (C ₆ -C ₂₀ ) aryl groups, (C ₁ -C ₂₀ ) alkoxy groups, (C ₁ -C ₂₀ ) alkylsiloxy groups and (C ₆ -C ₂₀ ) aryloxy groups. And,
n is an integer of 1 to 5,
Ar ¹ and Ar ² are the same or different, and each independently a ligand having a cyclopentadienyl skeleton, Ar ¹ and Ar ² is unsubstituted, halogen, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl silyl group and a silyl group (C ₆ ~ C ₂₀ ) aryl group, and the substituents may be bonded to each other to form a ring,
B is a component for ligating the ligands Ar ¹ and Ar ² without directly coordinating to the transition metal M and is a group consisting of carbon (C), silicon (Si), germanium (Ge), nitrogen (N) Including the selected element,
L is hydrogen, (C ₁ ~ C ₂₀₎ alkyl, (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀ ) aryl, (C ₆ ~ C ₂₀₎ aryl (C ₁ ~ C ₂₀₎ alkyl, (C ₁ ~ C ₂₀₎ alkyl (C ₆ ~ C ₂₀₎ aryl, (C ₆ ~ C ₂₀₎ aryl silyl group, and Silyl (C ₆ -C ₂₀ ) aryl group,
m varies depending on the kind of B, and is 1 or 2. The polyolefin composition according to claim 1, wherein the metallocene supported catalyst comprises a promoter compound selected from the group consisting of compounds represented by the following formulas (3) to (5):
(3)

[Chemical Formula 4]

[Chemical Formula 5]

In the above formulas (3) to (5)
Y ¹ is a (C ₁ -C ₁₀ ) alkyl group,
q is an integer of 1 to 70,
Y ² to Y ⁴ are the same or different, (C ₁ ~ C ₁₀₎ alkyl, (C ₁ ~ C ₁₀₎ alkoxy group and is independently selected from the group consisting of halogen, just one of Y ² to Y ⁴ Is a (C ₁ -C ₁₀ ) alkyl group,
C is a hydrogen ion-binding cation of Lewis base, or a metal or non-metal compound having oxidizing power,
And D is a compound of an organic substance and an element selected from the group consisting of the elements of Groups 5 to 15 on the periodic table. 8. The polyolefin composition according to claim 7, wherein the metallocene supported catalyst comprises a metallocene compound represented by the following general formula (1) or (2)
[Chemical Formula 1]

(2)

In the above formulas (1) and (2)
M is zirconium or hafnium,
X is a halogen group,
n is 2,
Ar ¹ and Ar ² are the same or different and are each independently cyclopentadienyl, indenyl or fluorenyl, Ar ¹ and Ar ² are each independently selected from the group consisting of a halogen atom, a (C ₁ -C ₂₀ ) (C ₃ ~ C ₂₀₎ cycloalkyl, (C ₁ ~ C ₂₀₎ alkyl silyl group, the silyl (C ₁ ~ C ₂₀₎ alkyl, halo (C ₁ ~ C ₂₀₎ alkyl, (C ₆ ~ C ₂₀₎ aryl group (C ₆ -C ₂₀ ) aryl (C ₁ -C ₂₀ ) alkyl, (C ₁ -C ₂₀ ) alkyl (C ₆ -C ₂₀ ) aryl, (C ₆ -C ₂₀ ) arylsilyl and silyl ₆ to C ₂₀ ) aryl groups, and the substituents may be bonded to each other to form a ring,
B is (C ₁ -C ₆ ) alkylene,
L is hydrogen or a (C ₁ -C ₂₀ ) alkyl group,
m is 1 or 2; The method according to claim 8, wherein the compound represented by Formula 3 is at least one selected from the group consisting of methylaluminoxane, ethylaluminoxane, butylaluminoxane, hexylaluminoxane, octylaluminoxane, Decylaluminoxane, and the like.
The compound represented by the general formula (4) may be prepared by reacting trimethylaluminum, triethylaluminum, tributylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminium, Tridecylaluminum, dimethylaluminum methoxide, diethylaluminum methoxide, dibutylaluminum methoxide, dimethylaluminum chloride, diethylaluminium methoxide, But are not limited to, diethylaluminum chloride, dibutylaluminum chloride, methylaluminum dimethoxide, ethylaluminum dimethoxide, butylaluminum dimethoxide, methyl Methylaluminum dichloride, ethylaluminium dichloride, Fluoride (ethylaluminum dichloride), and butyl aluminum dichloride num will be selected from the group consisting of (butylaluminum dichloride),
The compound represented by the general formula (5) is preferably a compound selected from the group consisting of triphenylcarbenium tetrakis (pentafluorophenyl) borate, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate Tripropylammonium tetraphenylborate, tributylammonium tetraphenylborate, trimethylammonium tetrakis (pentafluorophenyl) borate, triethylammonium tetrakis (triphenylphosphine) borate, Triethylammonium tetrakis (pentafluorophenyl) borate, tripropylammonium tetrakis (pentafluorophenyl) borate, tributylammonium tetrakis (pentafluorophenyl) borate, anilinium tetrakis (pentafluorophenyl) borate, anilinium tetraphenylborate, anilinium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate), pyridinium tetraphenylborate, pyridinium tetrakis (pentafluorophenyl) borate, (Pentafluorophenyl) borate, silver tetrakis (pentafluorophenyl) borate, silver tetraphenylborate, silver tetrakis (pentafluorophenyl) borate, Tris (pentafluorophenyl) borane, tris (2,3,5,6-tetrafluorophenyl) borane (tris (2,3,5,6-tetrafluo tris (2,3,4,5-tetraphenylphenyl) borane, and tris (3,4,5-trifluorophenyl) borane, Tris (3,4,5-trifluorophenyl) borane). ≪ / RTI > The method of claim 1, wherein the metallocene supported catalyst is selected from the group consisting of silica, alumina, magnesium chloride, calcium chloride, borocite, zeolite, magnesium oxide, zirconium oxide, titanium oxide, boron trioxide, Thorium, and a complex thereof. The polyolefin composition according to claim 1, The polyolefin composition according to claim 1, wherein the two kinds of polyolefins are produced by polymerization via olefin gas phase process, slurry process, slurry loop process or solution process.

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