Olefin polymer and method for producing the same

Abstract

The present invention relates to an olefin polymer and a method for producing the same. The olefin polymer according to a specific embodiment of the present invention has excellent melt strength and outstanding bubble stability during blown film molding.

Description

Technical Field

[0001] The present invention relates to an olefin polymer and a method for producing the same. Specifically, the present invention relates to an olefin polymer having excellent melt strength and a method for producing the same. Background Art

[0002] Metallocene catalysts, one of the catalysts used for olefin polymerization, are compounds composed of ligands such as cyclopentadienyl, indenyl, or cycloheptadienyl coordinated to transition metals or transition metal halides, and have a basic sandwich structure.

[0003] Ziegler-Natta catalysts, another catalyst used for olefin polymerization, have active sites (i.e., metal components) dispersed on an inert solid surface, resulting in heterogeneous properties. In contrast, metallocene catalysts are compounds with a fixed structure, and therefore are known as single-site catalysts, where all active sites exhibit identical polymerization characteristics. Polymers polymerized using these metallocene catalysts have a narrow molecular weight distribution and a uniform distribution of comonomers, resulting in higher copolymerization activity than Ziegler-Natta catalysts.

[0004] On the other hand, linear low-density polyethylene (LLDPE) is produced by copolymerizing ethylene and alpha-olefins under low pressure using a polymerization catalyst. It has a narrow molecular weight distribution, short chain branches (SCB) of fixed length, and generally lacks long chain branches (LCB). Films made from LLDPE not only possess the properties of conventional polyethylene but also have high breaking strength and elongation, as well as excellent tear strength and impact strength. Therefore, it is widely used in stretch films and cover films, where existing low-density polyethylene (LDPE) or high-density polyethylene (HDPE) is difficult to use.

[0005] However, in order to mold an olefin polymer produced using a metallocene catalyst into a blown film, excellent melt strength is required. Summary of the Invention

[0006] An object of the present invention is to provide an olefin polymer having excellent melt strength.

[0007] Another object of the present invention is to provide a method for producing the above-mentioned olefin-based polymer.

[0008] According to a specific embodiment of the present invention, an olefin polymer is provided, wherein the density of the olefin polymer (1) is 0.9 to 0.95 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (melt flow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 55 mN or more; and (5) the maximum processing speed is 550 mm / s or more.

[0009] In a specific embodiment of the present invention, the olefin polymer may be (1) a polymer having a density of 0.915 to 0.945 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (melt flow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 60 mN or more; and (5) the maximum processing speed is 570 mm / s or more.

[0010] In a preferred embodiment of the present invention, the olefin polymer may be (1) an olefin polymer having a density of 0.915 to 0.942 g / cm 3 ; (2) a melt index of 0.5 to 3.5 g / 10 min measured at 190°C under a load of 2.16 kg; (3) an MFR of 20 to 50; (4) a melt tension of 60 to 100 mN at a processing speed of 350 mm / s; and (5) a maximum processing speed of 570 to 800 mm / s.

[0011] In a specific example of the present invention, the above-mentioned olefin-based polymer can be produced by polymerizing olefin-based monomers in the presence of a composite catalyst, wherein the above-mentioned composite catalyst comprises at least one first transition metal compound represented by the following chemical formula 1, and at least one second transition metal compound selected from the compound represented by the following chemical formula 2 and the compound represented by the following chemical formula 3.

[0012] [Chemical Formula 1]

[0013]

[0014] [Chemical Formula 2]

[0015]

[0016] [Chemical Formula 3]

[0017]

[0018] In the above Chemical Formulas 1 to 3, M1 and M2 are different from each other and are each independently titanium (Ti), zirconium (Zr), or hafnium (Hf).

[0019] X is independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 Alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, or C 1-20 Alkylamide,

[0020] R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamide, substituted or unsubstituted C 6-20 Arylamide, substituted or unsubstituted C 1-20 Alkylene, or substituted or unsubstituted C 1-20 silyl, and R1 to R 10 Each independently connects adjacent groups to form a substituted or unsubstituted saturated or unsaturated C 4-20 ring.

[0021] In a specific embodiment of the present invention, M1 and M2 are different from each other and are each zirconium or hafnium, and X is each halogen or C 1-20 Alkyl, R1 to R 10 Each may be hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C1-20 Alkenyl, or substituted or unsubstituted C 6-20 Aryl.

[0022] In a preferred embodiment of the present invention, M1 may be hafnium, M2 may be zirconium, and X may be chlorine or methyl.

[0023] In a preferred embodiment of the present invention, the first transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 1-1 and 1-2, and the second transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 2-1, 2-2 and 3-1.

[0024] [Chemical Formula 1-1] [Chemical Formula 1-2]

[0025]

[0026] [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 3-1]

[0027]

[0028] In the above chemical formula, Me is a methyl group.

[0029] In a specific example of the present invention, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 100:1 to 1:100.

[0030] In a specific example of the present invention, the catalyst may include at least one co-catalyst selected from the group consisting of the compound represented by the following Chemical Formula 4, the compound represented by the following Chemical Formula 5, and the compound represented by the following Chemical Formula 6.

[0031] [Chemical Formula 4]

[0032]

[0033] [Chemical Formula 5]

[0034]

[0035] [Chemical Formula 6]

[0036] [LH] + [Z(A)4] - or [L] + [Z(A)4] -

[0037] In the above chemical formula 4, n is an integer greater than 2, R a Halogen atoms, C 1-20 Hydrocarbon, or halogen-substituted C 1-20 Hydrocarbon group,

[0038] In the above chemical formula 5, D is aluminum (Al) or boron (B), R b 、R c and R d are each independently a halogen atom, C 1-20 Hydrocarbon, halogen-substituted C 1-20 Hydrocarbon, or C 1-20 Alkoxy,

[0039] In the above chemical formula 6, L is a neutral or cationic Lewis base, [LH] + and [L] + is a Bronsted acid, Z is a Group 13 element, and A is independently a substituted or unsubstituted C 6-20 Aryl, or substituted or unsubstituted C 1-20 alkyl.

[0040] In a specific example of the present invention, the catalyst may further include a transition metal compound, a co-catalyst compound, or a carrier supporting both of them.

[0041] In a preferred embodiment of the present invention, the support may include at least one selected from silicon oxide, aluminum oxide, and magnesium oxide.

[0042] The total amount of the composite transition metal compound supported on the carrier is 0.001 to 1 mmole based on 1 g of the carrier, and the total amount of the co-catalyst compound supported on the carrier is 2 to 15 mmole based on 1 g of the carrier.

[0043] In a specific example of the present invention, the olefin polymer is a copolymer of an olefin monomer and an olefin comonomer. Specifically, the olefin monomer is ethylene, and the olefin comonomer can be at least one selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, and 1-hexadecene. Preferably, the olefin polymer is a linear low-density polyethylene in which the olefin monomer is ethylene and the olefin comonomer is 1-hexene.

[0044] According to a specific embodiment of the present invention, a method for producing an olefin-based polymer is provided, comprising the step of polymerizing an olefin-based monomer in the presence of a composite catalyst to obtain an olefin-based polymer, wherein the composite catalyst comprises at least one first transition metal compound represented by the above-mentioned chemical formula 1 and at least one second transition metal compound selected from the group consisting of a compound represented by the above-mentioned chemical formula 2 and a compound represented by the above-mentioned chemical formula 3, and the density (1) of the olefin-based polymer is 0.9 to 0.95 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16) is 0.5 to 1.5 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (melt flow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 55 mN or more; and (5) the maximum processing speed is 550 mm / s or more.

[0045] In a specific example of the present invention, the polymerization of the olefinic monomers can be carried out by gas phase polymerization. Specifically, the polymerization of the olefinic monomers can be carried out in a gas phase fluidized bed reactor.

[0046] The olefin polymer according to the specific example of the present invention has excellent melt strength and outstanding bubble stability during blown film molding. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a graph showing the melt strength of the olefin polymers of Examples 1 and 2 and Comparative Example 1 versus the maximum processing speed. DETAILED DESCRIPTION

[0048] Hereinafter, the present invention will be described in more detail.

[0049] Olefin polymers

[0050] According to a specific embodiment of the present invention, an olefin polymer is provided, wherein the density of the olefin polymer (1) is 0.9 to 0.95 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (melt flow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 55 mN or more; and (5) the maximum processing speed is 550 mm / s or more.

[0051] In a specific embodiment of the present invention, the density of the olefin polymer (1) may be 0.915 to 0.945 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6) and the melt index (I 2.16 ) ratio (meltflow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 60 mN or more; and (5) the maximum processing speed is 570 mm / s or more.

[0052] In a preferred embodiment of the present invention, the olefin polymer may be (1) an olefin polymer having a density of 0.915 to 0.942 g / cm 3 ; (2) a melt index of 0.5 to 3.5 g / 10 min measured at 190°C under a load of 2.16 kg; (3) an MFR of 20 to 50; (4) a melt tension of 60 to 100 mN at a processing speed of 350 mm / s; and (5) a maximum processing speed of 570 to 800 mm / s.

[0053] In a specific embodiment of the present invention, the density of the olefin polymer is 0.9 to 0.95 g / cm 3 Preferably, the density of the olefin polymer can be 0.91 to 0.945 g / cm 3 , 0.915~0.945g / cm 3 , 0.91~0.93g / cm 3 , 0.915~0.942g / cm 3 or 0.915~0.925g / cm 3 .

[0054] In a specific example of the present invention, the melt index (I 2.16 ) is 0.1 to 5.0 g / 10 minutes. Preferably, the melt index of the olefin polymer measured at 190°C with a load of 2.16 kg may be 0.3 to 4.0 g / 10 minutes, 0.5 to 3.5 g / 10 minutes, or 0.5 to 3.0 g / 10 minutes.

[0055] In a specific example of the present invention, the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (melt flow ratio; MFR) is 20 or more. Preferably, the MFR of the olefin-based polymer may be 22 or more or 20-50.

[0056] In a specific example of the present invention, the melt tension of the olefin polymer at a processing speed of 350 mm / s is 55 mN. Preferably, the melt tension of the olefin polymer at a processing speed of 350 mm / s can be 60 mN or greater, or 60 to 100 mN. Melt tension is a measure of the melt strength of an olefin polymer. The higher the melt tension, the better the bubble stability, which is the property of maintaining the film's shape without oscillation during blown film production using the olefin polymer.

[0057] In specific embodiments of the present invention, the maximum processing speed (velocity at break) of the olefin polymer is 550 mm / s or greater. Preferably, the maximum processing speed of the olefin polymer can be 570 mm / s or greater, or between 570 and 800 mm / s. A higher maximum processing speed increases the line speed of the film extrusion process, thereby increasing film production.

[0058] According to a specific example of the present invention, an olefin-based polymer is produced by polymerizing an olefin-based monomer in the presence of a composite catalyst, wherein the composite catalyst comprises at least one first transition metal compound represented by the following Chemical Formula 1, and at least one second transition metal compound selected from the group consisting of a compound represented by the following Chemical Formula 2 and a compound represented by the following Chemical Formula 3.

[0059] [Chemical Formula 1]

[0060]

[0061] [Chemical Formula 2]

[0062]

[0063] [Chemical Formula 3]

[0064]

[0065] In the above Chemical Formulas 1 to 3, M1 and M2 are different from each other and are each independently titanium (Ti), zirconium (Zr), or hafnium (Hf). Specifically, M1 and M2 may be different from each other and each may be zirconium or hafnium. Preferably, M1 may be hafnium and M2 may be zirconium.

[0066] X is independently halogen, C 1-20 Alkyl, C 2-20 Alkenyl, C 2-20 Alkynyl, C 6-20 Aryl, C 1-20 Alkyl C 6-20 Aryl, C 6-20 Aryl C 1-20 Alkyl, C 1-20Alkylamide or C 6-20 Specifically, X can be halogen or C 1-20 Preferably, X can be chlorine or methyl.

[0067] R1 to R 10 are each independently hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 2-20 Alkenyl, substituted or unsubstituted C 6-20 Aryl, substituted or unsubstituted C 1-20 Alkyl C 6-20 Aryl, substituted or unsubstituted C 6-20 Aryl C 1-20 Alkyl, substituted or unsubstituted C 1-20 Heteroalkyl, substituted or unsubstituted C 3-20 Heteroaryl, substituted or unsubstituted C 1-20 Alkylamide, substituted or unsubstituted C 6-20 Arylamide, substituted or unsubstituted C 1-20 Alkylene, or substituted or unsubstituted C 1-20 Silyl, wherein R1 to R 10 Each independently connects adjacent groups to form a substituted or unsubstituted saturated or unsaturated C 4-20 Specifically, R1 to R 10 Each may be hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 1-20 Alkenyl, or substituted or unsubstituted C 6-20 Aryl.

[0068] In a specific embodiment of the present invention, M1 and M2 are different from each other and are each zirconium or hafnium, and X is each halogen or C 1-20 Alkyl, R1 to R 10 Each may be hydrogen, substituted or unsubstituted C 1-20 Alkyl, substituted or unsubstituted C 1-20 Alkenyl, or substituted or unsubstituted C 6-20 Aryl.

[0069] In a preferred embodiment of the present invention, M1 may be hafnium, M2 may be zirconium, and X may be chlorine or methyl.

[0070] In a preferred embodiment of the present invention, the first transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 1-1 and 1-2, and the second transition metal compound may be at least one of the transition metal compounds represented by the following chemical formulas 2-1, 2-2 and 3-1.

[0071] [Chemical Formula 1-1] [Chemical Formula 1-2]

[0072]

[0073] [Chemical Formula 2-1] [Chemical Formula 2-2] [Chemical Formula 3-1]

[0074]

[0075] In the above chemical formula, Me is a methyl group.

[0076] In a specific example of the present invention, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 100:1 to 1:100. Preferably, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 50:1 to 1:50. Preferably, the molar ratio of the first transition metal compound to the second transition metal compound is in the range of 10:1 to 1:10.

[0077] In a specific example of the present invention, the catalyst may include at least one co-catalyst compound selected from the group consisting of the compound represented by the following Chemical Formula 4, the compound represented by the following Chemical Formula 5, and the compound represented by the following Chemical Formula 6.

[0078] [Chemical Formula 4]

[0079]

[0080] In the above chemical formula 4, n can be an integer greater than 2, R a It can be a halogen atom, C 1-20 Hydrocarbons, or C substituted by halogen 1-20 Hydrocarbons. Specifically, R a It may be methyl, ethyl, n-butyl or isobutyl.

[0081] [Chemical Formula 5]

[0082]

[0083] In the above chemical formula 5, D is aluminum (Al) or boron (B), R b 、R c and R d are each independently a halogen atom, C 1-20 Hydrocarbon, halogen-substituted C 1-20 Hydrocarbon, or C 1-20 Specifically, when D is aluminum (Al), R b 、R c and R d Each independently can be methyl or isobutyl, when D is boron (B), R b 、R c and Rd Each may be a pentafluorophenyl group.

[0084] [Chemical Formula 6]

[0085] [LH] + [Z(A)4] - or [L] + [Z(A)4] -

[0086] In the above chemical formula 6, L is a neutral or cationic Lewis base, [LH] + and [L] + is a Bronsted acid, Z is a Group 13 element, and A is independently a substituted or unsubstituted C 6-20 Aryl, or substituted or unsubstituted C 1-20 Specifically, [LH] + It can be a dimethylanilinium cation, [Z(A)4] - It can be [B(C6F5)4] - , [L] + It can be [(C6H5)3C] + .

[0087] Specifically, examples of the compound represented by the above Chemical Formula 4 include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, and the like, preferably methylaluminoxane, but not limited thereto.

[0088] Examples of the compound represented by Chemical Formula 5 include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylaluminum chloride, triisopropylaluminum, tri-sec-butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri-p-tolylaluminum, dimethylaluminum methoxide, dimethylaluminum ethoxide, trimethylboron, triethylboron, triisobutylboron, tripropylboron, and tributylboron. Preferred examples include trimethylaluminum, triethylaluminum, and triisobutylaluminum, but not limited thereto.

[0089] Examples of the compound represented by the above chemical formula 6 include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra(p-tolyl)boron, trimethylammonium tetra(o-, p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, trimethylammonium tetra(p-trifluoromethylphenyl)boron, tributylammonium tetra(pentafluorophenyl)boron, N,N-diethylanilinium tetraphenylboron, N,N-diethylanilinium tetra(pentafluorophenyl)boron, diethylammonium tetra(pentafluorophenyl)boron, and triphenylammonium tetra(pentafluorophenyl)boron. Tetraphenylborane, trimethyl Tetraphenylboron, triethylammonium tetraphenylaluminum, tributylammonium tetraphenylaluminum, trimethylammonium tetraphenylaluminum, tripropylammonium tetraphenylaluminum, trimethylammonium tetra(p-tolyl)aluminum, tripropylammonium tetra(p-tolyl)aluminum, triethylammonium tetra(o-, p-dimethylphenyl)aluminum, tributylammonium tetra(p-trifluoromethylphenyl)aluminum, trimethylammonium tetra(p-trifluoromethylphenyl)aluminum, tributylammonium tetra(pentafluorophenyl)aluminum, N,N-diethylanilinium tetraphenylaluminum, N,N-diethylanilinium tetra(pentafluorophenyl)aluminum, diethylammonium tetra(pentafluorophenyl)aluminum, triphenyl Tetraphenylaluminum, trimethyl Tetraphenylaluminum, tripropylammonium tetra(p-tolyl)boron, triethylammonium tetra(o-, p-dimethylphenyl)boron, tributylammonium tetra(p-trifluoromethylphenyl)boron, triphenylcarbon Tetrakis(p-trifluoromethylphenyl)boron, triphenylcarbon Tetrakis(pentafluorophenyl)boron, etc.

[0090] In a specific example of the present invention, the catalyst may further comprise a transition metal compound, a co-catalyst compound, or a carrier supporting both of them. Specifically, the carrier may support both the transition metal compound and the co-catalyst compound.

[0091] At this time, the carrier may include a substance containing a hydroxyl group on the surface. Preferably, a substance having a hydroxyl group and a siloxane group that has been dried and the surface has been dehydrated and that is highly reactive can be used. For example, the carrier may include at least one selected from silicon oxide, aluminum oxide, and magnesium oxide. Specifically, silicon oxide, silicon oxide-aluminum oxide, and silicon oxide-magnesium oxide, etc., dried at high temperatures, may be used as carriers. These may typically contain oxides, carbonates, sulfates, and nitrate components such as Na2O, K2CO3, BaSO4, and Mg(NO3)2. In addition, they may also include carbon, zeolite, magnesium chloride, etc. However, the carrier is not limited thereto and is not particularly limited as long as it can support transition metal compounds and co-catalyst compounds.

[0092] The average particle size of the carrier may be 10 to 250 μm, preferably, the average particle size may be 10 to 150 μm, and more preferably, the average particle size may be 20 to 100 μm.

[0093] The micropore volume of the carrier may be 0.1 to 10 cc / g, preferably 0.5 to 5 cc / g, and more preferably 1.0 to 3.0 cc / g.

[0094] The specific surface area of ​​the carrier may be 1 to 1000 m2 / g, preferably 100 to 800 m2 / g, and more preferably 200 to 600 m2 / g.

[0095] In a preferred embodiment of the present invention, the carrier can be silicon oxide. In this case, the silicon oxide can be dried at a temperature of 200 to 900°C. The drying temperature is preferably 300 to 800°C, and more preferably 400 to 700°C. If the drying temperature is less than 200°C, excessive moisture may occur, causing the surface moisture to react with the co-catalyst compound. If the drying temperature is greater than 900°C, the carrier structure may disintegrate.

[0096] The concentration of hydroxyl groups in the dried silica can be 0.1 to 5 mmole / g, preferably 0.7 to 4 mmole / g, and more preferably 1.0 to 2 mmole / g. If the concentration of hydroxyl groups is less than 0.1 mmole / g, the loading of the first co-catalyst compound is low, while if it is greater than 5 mmole / g, deactivation of the catalyst component may occur.

[0097] The total amount of the transition metal compound supported on the carrier can be 0.001 to 1 mmole based on 1 g of the carrier. When the ratio of the transition metal compound to the carrier satisfies the above range, the supported catalyst exhibits appropriate activity, which is advantageous in maintaining catalyst activity and economic efficiency.

[0098] The total amount of the promoter compound supported on the carrier can be 2 to 15 mmole based on 1 g of the carrier. When the ratio of the promoter compound to the carrier satisfies the above range, it is advantageous in terms of maintaining catalyst activity and economic efficiency.

[0099] The carrier may be one or more than one. For example, the transition metal compound and the co-catalyst compound may both be supported on one carrier, or the transition metal compound and the co-catalyst compound may each be supported on two or more carriers. Alternatively, only one of the transition metal compound and the co-catalyst compound may be supported on the carrier.

[0100] As a method for supporting the transition metal compound and / or the co-catalyst compound that can be used in the olefin polymerization catalyst, a physical adsorption method or a chemical adsorption method can be used.

[0101] For example, the physical adsorption method may be a method in which a solution containing a transition metal compound dissolved therein is brought into contact with a carrier and then dried; a method in which a solution containing a transition metal compound and a co-catalyst compound dissolved therein is brought into contact with a carrier and then dried to produce a carrier loaded with the transition metal compound; separately, a solution containing a co-catalyst compound dissolved therein is brought into contact with a carrier and then dried to produce a carrier loaded with the co-catalyst compound; and then the materials are mixed, etc.

[0102] The chemical adsorption method can be a method in which the surface of the carrier is first loaded with a co-catalyst compound and then the co-catalyst compound is loaded with a transition metal compound; or a method in which the functional groups on the surface of the carrier (for example, when using silicon oxide, the hydroxyl groups (-OH) on the surface of silicon oxide) are covalently bonded to the catalyst compound, etc.

[0103] In a specific example of the present invention, the olefin polymer can be a homopolymer of an olefin monomer or a copolymer of an olefin monomer and a comonomer. Preferably, the olefin polymer is a copolymer of an olefin monomer and an olefin comonomer.

[0104] Among them, the olefin monomer is selected from C 2-20 Alpha-olefins (α-olefin), C 1-20 Diolefins, C 3-20 Cycloolefin and C 3-20 At least one of cyclodiolefins.

[0105] For example, the olefin monomer may be ethylene, propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene or 1-hexadecene, and the olefin polymer may be a homopolymer containing only one of the above-mentioned olefin monomers, or may be a copolymer containing two or more of the above-mentioned olefin monomers.

[0106] In an exemplary embodiment, the olefin polymer may be ethylene and C 3-20 The copolymer is formed by copolymerization of alpha-olefins. Preferably, the olefin-based polymer may be a linear low-density polyethylene in which the olefin-based monomer is ethylene and the olefin-based comonomer is 1-hexene.

[0107] In this case, the ethylene content is preferably 55 to 99.9% by weight, more preferably 90 to 99.9% by weight, and the alpha-olefin comonomer content is preferably 0.1 to 45% by weight, more preferably 0.1 to 10% by weight.

[0108] Method for producing olefin polymer

[0109] According to a specific example of the present invention, a method for producing an olefin-based polymer is provided, comprising the step of polymerizing an olefin-based monomer in the presence of a composite catalyst to obtain an olefin-based polymer, wherein the composite catalyst comprises at least one first transition metal compound represented by the following chemical formula 1, and at least one second transition metal compound selected from a compound represented by the following chemical formula 2 and a compound represented by the following chemical formula 3.

[0110] [Chemical Formula 1]

[0111]

[0112] [Chemical Formula 2]

[0113]

[0114] [Chemical Formula 3]

[0115]

[0116] In the above chemical formula, M1, M2, X and R1 to R 10 Same as the description in the above-mentioned olefin polymer section.

[0117] As described above, the olefin polymer produced by the production method according to one embodiment of the present invention has a density (1) of 0.9 to 0.95 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (melt flow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 55 mN or more; and (5) the maximum processing speed is 550 mm / s or more.

[0118] In a specific embodiment of the present invention, the density of the olefin polymer (1) may be 0.915 to 0.945 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio (meltflow ratio; MFR) is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 60 mN or more; and (5) the maximum processing speed is 570 mm / s or more.

[0119] In a preferred embodiment of the present invention, the olefin polymer may be (1) an olefin polymer having a density of 0.915 to 0.942 g / cm 3; (2) a melt index of 0.5 to 3.5 g / 10 min measured at 190°C under a load of 2.16 kg; (3) an MFR of 20 to 50; (4) a melt tension of 60 to 100 mN at a processing speed of 350 mm / s; and (5) a maximum processing speed of 570 to 800 mm / s.

[0120] In specific examples of the present invention, the olefin polymer can be polymerized by, for example, free radical, cationic, coordination, condensation, addition, or other polymerization reactions, but is not limited thereto.

[0121] As one embodiment of the present invention, the olefin polymer can be produced by gas phase polymerization, solution polymerization, or slurry polymerization. Preferably, the polymerization of the olefin monomer can be carried out by gas phase polymerization, specifically, the polymerization of the olefin monomer can be carried out in a gas phase fluidized bed reactor.

[0122] When the olefin polymer is produced by solution polymerization or slurry polymerization, examples of solvents that can be used include C 2+, C 3+, C 4+, C 5+, C 6+, C 7+, C 8+, C 9+, C 10+, C 11+, C 12+, C 13+, C 14+, C 15+, C 16+, C 17+, C 18+, C 19+, C 5-12 Aliphatic hydrocarbon solvents; aromatic hydrocarbon solvents such as toluene and benzene; hydrocarbon solvents substituted with chlorine atoms such as dichloromethane and chlorobenzene; and mixtures thereof, but not limited thereto.

[0123] Modes for Carrying Out the Invention

[0124] Example

[0125] The present invention will be described in more detail below by way of examples. However, the following examples are only for illustrating the present invention, and the scope of the present invention is not limited thereto.

[0126] Manufacturing Example

[0127] The transition metal compound of Chemical Formula 1-1 (bis(n-propylcyclopentadienyl)hafnium dichloride) and the transition metal compound of Chemical Formula 2-1 (bis(n-butylcyclopentadienyl)zirconium dichloride) were purchased from TCI and used without further purification.

[0128] 892 g of a 10% methylaluminoxane toluene solution was added to 4.47 g of the transition metal compound of Chemical Formula 1-1 and 1.67 g of the transition metal compound of Chemical Formula 2-1, and the mixture was stirred at room temperature for 1 hour. The resulting solution was added to 200 g of silica (XPO-2402), and 1.5 liters of toluene was further added, followed by stirring at 70°C for 2 hours. The supported catalyst was washed with 500 ml of toluene and dried under vacuum at 60°C overnight to obtain 280 g of a powdered supported catalyst.

[0129] Examples 1-2

[0130] An ethylene / 1-hexene copolymer was produced using a gas phase fluidized bed reactor in the presence of the supported catalyst obtained in Production Example 1. The ethylene partial pressure in the reactor was maintained at approximately 15 kg / cm 2 , and maintain the polymerization temperature at 70-90°C.

[0131] The polymerization conditions of the above examples are shown in Table 1 below.

[0132] [Table 1]

[0133] Example 1 Example 2 Polymerization temperature (℃) 75.4 80.9 Catalyst injection rate (g / h) 2.0 1.4 Hydrogen injection rate (g / h) 2.22 2.34 1-Hexene injection maximum (kg / h) 1.60 1.63 Hydrogen / ethylene concentration (%) ratio 0.047 0.048 1-Hexene / ethylene concentration (%) ratio 2.096 1.993

[0134] Comparative Example 1

[0135] For comparison, Dow's DOWLEX 2045G (density 0.9200 g / cm 3 , melt index 1.0g / 10min).

[0136] Test example

[0137] The physical properties of the olefin polymers of the above examples were measured according to the following methods and standards. The results are shown in Table 2 below.

[0138] (1) Density

[0139] The measurement was performed according to ASTM D1505.

[0140] (2) Melt index and melt flow ratio (MFR)

[0141] According to ASTM D 1238, the melt index was measured at 190°C with a load of 21.6 kg and with a load of 2.16 kg, and the ratio (MI 21.6 / MI 2.16 ).

[0142] (3) Melt strength

[0143] Through a capillary with a length of 30 mm, a diameter of 2 mm, a shear rate of 72 / s and / or an initial velocity of 18 mm / s and an acceleration of 12 mm / s 2 The melt tension and maximum processing speed were measured using a wheel.

[0144] [Table 2]

[0145]

[0146] As shown in Table 2 and Figure 1 As confirmed, the olefin polymer according to the specific example of the present invention has excellent melt strength represented by melt tension and maximum processing speed, and is excellent in bubble stability during blown film molding.

[0147] Industrial Application Possibilities

[0148] Therefore, the present invention can provide an olefin-based polymer having excellent melt strength.

Claims

1. A method for producing an olefin-based polymer, comprising the step of polymerizing an olefin-based monomer in the presence of a composite catalyst to obtain an olefin-based polymer, wherein the composite catalyst comprises at least one first transition metal compound selected from the compounds represented by the following chemical formulas 1-1 and 1-2, and at least one second transition metal compound selected from the compounds represented by the following chemical formulas 2-1, 2-2, and 3-1, and wherein the density (1) of the olefin-based polymer is 0.9 to 0.95 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio, i.e., MFR, is 20 or more; (4) a melt tension of 55 mN or more at a processing speed of 350 mm / s; and (5) a maximum processing speed of 550 mm / s or more, The polymerization of olefin monomers in the presence of the composite catalyst is carried out at a polymerization temperature of 70.0° C. to 75.4° C.: In the chemical formula, Me is a methyl group.

2. The method for producing an olefin-based polymer according to claim 1, wherein The density of the olefin polymer (1) is 0.915 to 0.945 g / cm 3 (2) Melt index (I) measured at 190°C with a load of 2.16 kg 2.16 ) is 0.1 to 5.0 g / 10 minutes; (3) the melt index (I 21.6 ) and the melt index (I 2.16 ) ratio, i.e., MFR, is 20 or more; (4) the melt tension at a processing speed of 350 mm / s is 60 mN or more; and (5) the maximum processing speed is 570 mm / s or more.

3. The method for producing an olefin-based polymer according to claim 1, wherein The molar ratio of the first transition metal compound to the second transition metal compound is in the range of 100:1 to 1:

100.

4. The method for producing an olefin-based polymer according to claim 1, wherein The catalyst comprises at least one co-catalyst compound selected from the group consisting of a compound represented by the following Chemical Formula 4, a compound represented by Chemical Formula 5, and a compound represented by Chemical Formula 6, [Chemical Formula 4] [Chemical Formula 5] [Chemical Formula 6] [L-H] + [Z(A)4] - or [L] + [Z(A)4] - In the chemical formula 4, n is an integer greater than or equal to 2, and R a Halogen atoms, C 1-20 Hydrocarbon, or halogen-substituted C 1-20 Hydrocarbon group, In the chemical formula 5, D is aluminum (Al) or boron (B), R b 、R c and R d are each independently a halogen atom, C 1-20 Hydrocarbon, halogen-substituted C 1-20 Hydrocarbon, or C 1-20 Alkoxy, In the chemical formula 6, L is a neutral or cationic Lewis base, [LH] + and [L] + is a Bronsted acid, Z is a Group 13 element, and A is independently a substituted or unsubstituted C 6-20 Aryl, or substituted or unsubstituted C 1-20 alkyl.

5. The method for producing an olefin-based polymer according to claim 4, wherein The catalyst further comprises a transition metal compound, a co-catalyst compound, or a carrier supporting both of them.

6. The method for producing an olefin-based polymer according to claim 5, wherein The support comprises at least one selected from the group consisting of silicon oxide, aluminum oxide, and magnesium oxide.

7. The method for producing an olefin-based polymer according to claim 5, wherein Based on 1 gram of the carrier, the total amount of the composite transition metal compound supported by the carrier is 0.001 to 1 mmole, and based on 1 gram of the carrier, the total amount of the co-catalyst compound supported by the carrier is 2 to 15 mmole.

8. The method for producing an olefin-based polymer according to claim 1, wherein The olefin-based polymer is a copolymer of an olefin-based monomer and an olefin-based comonomer.

9. The method for producing an olefin-based polymer according to claim 8, wherein The olefin monomer is ethylene, and the olefin comonomer is one or more selected from propylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene and 1-hexadecene.

10. The method for producing an olefin-based polymer according to claim 9, wherein The olefin-based polymer is a linear low-density polyethylene in which the olefin-based monomer is ethylene and the olefin-based comonomer is 1-hexene.

11. The method for producing an olefin-based polymer according to claim 1, wherein The polymerization of the olefin-based monomers is carried out by gas phase polymerization.

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