KR102894109B1 - Process for Preparing a Polyolefin - Google Patents

Abstract

The present invention relates to a method for producing an olefin polymer. Specifically, the present invention relates to a method for producing an olefin polymer capable of controlling the physical properties of the olefin polymer depending on the polymerization temperature. The method for producing an olefin polymer according to an embodiment of the present invention can control the physical properties of the olefin polymer, particularly the melt index ratio, depending on the polymerization temperature.

Description

Process for Preparing a Polyolefin

The present invention relates to a method for producing an olefin polymer. Specifically, the present invention relates to a method for producing an olefin polymer capable of controlling the physical properties of the olefin polymer depending on the polymerization temperature.

A metallocene catalyst, which is one of the catalysts used to polymerize olefins, is a compound in which a ligand such as cyclopentadienyl, indenyl, or cycloheptadienyl is coordinately bonded to a transition metal or transition metal halide compound, and has a basic sandwich structure.

Unlike Ziegler-Natta catalysts, which are other catalysts used to polymerize olefins, in which the metal component, which is the active site, is dispersed on an inert solid surface, resulting in non-uniform properties of the active site, metallocene catalysts are known as single-site catalysts because they are a single compound with a fixed structure, and all active sites have the same polymerization characteristics. Polymers polymerized with these metallocene catalysts have a narrow molecular weight distribution, a uniform distribution of comonomers, and higher copolymerization activity than Ziegler-Natta catalysts.

Meanwhile, linear low-density polyethylene (LLDPE) is manufactured by copolymerizing ethylene and alpha-olefin at low pressure using a polymerization catalyst, and has a narrow molecular weight distribution, short chain branches (SCB) of a constant length, and generally no long chain branches (LCB). Films manufactured with linear low-density polyethylene have the characteristics of general polyethylene, as well as high breaking strength and elongation, and excellent tear strength and impact strength, so they are widely used in stretch films and overlap films, which are difficult to apply to conventional low-density polyethylene or high-density polyethylene.

However, linear low-density polyethylene manufactured using a metallocene catalyst has poor processability due to its narrow molecular weight distribution, and films manufactured from it tend to have poor heat sealing properties.

Therefore, a method for producing an olefin polymer that can control the properties of the olefin polymer as needed is required.

For example, Korean Patent Application Publication No. 2021-0038236 discloses a method for predicting the melting index of an olefin polymer according to the concentration of a transition metal compound, the concentration of a cocatalyst, and the polymerization temperature, and Korean Patent Application Publication No. 2021-0049985 discloses a method for changing the comonomer content according to the polymerization temperature during olefin polymerization using a chromium oxide catalyst.

Republic of Korea Patent Application Publication No. 2021-0038236 Republic of Korea Patent Application Publication No. 2021-0049985

The purpose of the present invention is to provide a method for producing an olefin polymer, which can control the physical properties of the olefin polymer, particularly the melting index ratio, depending on the polymerization temperature.

According to one embodiment of the present invention for achieving the above object, there is provided a method of producing an olefin polymer, comprising: polymerizing an olefin monomer at a polymerization temperature of 75 to 95°C in the presence of a hybrid catalyst comprising 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, a compound represented by the following chemical formula 3, and a compound represented by the following chemical formula 4, wherein the olefin polymer has (1) a density of 0.915 to 0.985 g/cm3; (2) a melt index (MI _2.16 ) measured at 190°C under a 2.16 kg load of 0.01 to 10.0 g/10 min; (3) A method for producing an olefin polymer having a melt flow ratio (MFR) of 30 to 250 between a melt index (MI _21.6 ) measured at 190°C under a load of 21.6 kg and a melt index (MI _2.16 ) measured under a load of 2.16 kg is provided, and satisfying the following mathematical expression 1.

[Mathematical Formula 1]

In the above mathematical formula, T1 and T2 are polymerization temperatures (℃), respectively, and MFR ₁ and MFR ₂ represent the MFR of the olefin polymer manufactured under polymerization temperature conditions of T1 and T2 (℃), respectively.

[Chemical Formula 1]

[Chemical Formula 2] [Chemical Formula 3] [Chemical Formula 4]

In the chemical formula above, l1, l2, l3, and m1 are each independently integers from 0 to 4,

m2 and m3 are each independently integers from 0 to 2,

n1 and o1 are each independently integers from 0 to 5,

M is independently titanium (Ti), zirconium (Zr), or hafnium (Hf),

X is each 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 _1-20 alkylamido or C _6-20 arylamido,

R ₁ , R ₂ , R ₅ to R ₈ , R ₁₁ , R ₁₂ are each independently a substituted or unsubstituted C _1-20 alkyl, a substituted or unsubstituted C _2-20 alkenyl, a substituted or unsubstituted C _6-20 aryl, a substituted or unsubstituted C _1-20 alkyl C _6-20 aryl, a substituted or unsubstituted C _6-20 aryl C _1-20 alkyl, a substituted or unsubstituted C _1-20 heteroalkyl, a substituted or unsubstituted C _3-20 heteroaryl, a substituted or unsubstituted C _1-20 alkylamido, a substituted or unsubstituted C _6-20 arylamido, or a substituted or unsubstituted C _1-20 silyl, wherein each of these may independently form a substituted or unsubstituted saturated or unsaturated C _4-20 ring by connecting adjacent groups,

R ₃ , R ₄ , R ₉ , R ₁₀ , R ₁₃ and R ₁₄ are each independently a substituted or unsubstituted C _1-20 alkyl, a substituted or unsubstituted C _2-20 alkenyl, a substituted or unsubstituted C _6-20 aryl, a substituted or unsubstituted C _1-20 alkyl C _6-20 aryl, a substituted or unsubstituted C _6-20 aryl C _1-20 alkyl, a substituted or unsubstituted C _1-20 heteroalkyl, a substituted or unsubstituted C _3-20 heteroaryl, a substituted or unsubstituted C _1-20 alkylamido, a substituted or unsubstituted C _6-20 arylamido, or a substituted or unsubstituted C _1-20 silyl, wherein R ₃ and R ₄ , R ₉ and R ₁₀ , R ₁₃ and R ₁₄ are each independently connected to each other and substituted or may form an unsubstituted saturated or unsaturated C _2-20 ring.

In a specific example of the present invention, the transition metal compound of the above chemical formula 1 may be at least one of the transition metal compounds represented by the chemical formulas 1-1 to 1-10 below.

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

[Chemical Formula 1-3] [Chemical Formula 1-4]

[Chemical Formula 1-5] [Chemical Formula 1-6]

[Chemical Formula 1-7] [Chemical Formula 1-8]

[Chemical Formula 1-9] [Chemical Formula 1-10]

In the above chemical formula, Me is methyl, n -Bu is n -butyl, t -Bu is t -butyl, Ph is phenyl, and p -Tol is p -tolyl.

In a specific example of the present invention, the transition metal compound of the above chemical formula 2 may be at least one of the transition metal compounds represented by the chemical formulas 2-1 to 2-8 below, the transition metal compound of the above chemical formula 3 may be a transition metal compound represented by the chemical formula 3-1 below, and the transition metal compound of the above chemical formula 4 may be at least one of the transition metal compounds represented by the chemical formulas 4-1 to 4-2 below.

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

[Chemical Formula 2-4] [Chemical Formula 2-5] [Chemical Formula 2-6]

[Chemical Formula 2-7] [Chemical Formula 2-8] [Chemical Formula 3-1]

[Chemical Formula 4-1] [Chemical Formula 4-2]

In the chemical formula above, Me is methyl and Ph is phenyl.

In a specific embodiment of the present invention, the above catalyst may include at least one cocatalyst selected from the group consisting of a compound represented by Chemical Formula 5 below, a compound represented by Chemical Formula 6, and a compound represented by Chemical Formula 7.

[Chemical Formula 5]

[Chemical Formula 6]

[Chemical Formula 7]

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

In the above chemical formula 5, n is an integer greater than or equal to 2, R _a is a halogen atom, a C _1-20 hydrocarbon group, or a C _1-20 hydrocarbon group substituted with a halogen,

In the above chemical formula 6, D is aluminum (Al) or boron (B), R _b , R _c and R _d are each independently a halogen atom, a C _1-20 hydrocarbon group, a C _1-20 hydrocarbon group substituted with a halogen or a C _1-20 alkoxy group,

In the above chemical formula 7, L is a neutral or cationic Lewis base, [LH] ⁺ and [L] ⁺ are Bronsted acids, Z is a Group 13 element, and A is each independently a substituted or unsubstituted C _6-20 aryl group or a substituted or unsubstituted C _1-20 alkyl group.

In a specific embodiment of the present invention, the above catalyst may further comprise a carrier supporting a transition metal compound, a cocatalyst compound, or both.

In a preferred embodiment of the present invention, the carrier may comprise at least one selected from the group consisting of silica, alumina and magnesia.

Here, the total amount of the 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 cocatalyst compound supported on the carrier is 2 to 15 mmole based on 1 g of the carrier.

In a specific embodiment of the present invention, the olefin polymer is a copolymer of an olefin monomer and an olefin comonomer. Specifically, the olefin monomer may be ethylene, and the olefin comonomer may be at least one selected from the group consisting of 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 linear low-density polyethylene, in which the olefin monomer is ethylene and the olefin comonomer is 1-hexene.

The method for producing an olefin polymer according to an embodiment of the present invention can control the physical properties of the olefin polymer, particularly the melting index ratio, depending on the polymerization temperature.

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

Method for producing olefin polymers

A method for producing an olefin polymer, comprising: polymerizing an olefin monomer at a polymerization temperature of 75 to 95°C in the presence of a hybrid catalyst comprising 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, a compound represented by the following chemical formula 3, and a compound represented by the following chemical formula 4; wherein the olefin polymer has (1) a density of 0.915 to 0.985 g/cm3; (2) a melt index (MI _2.16 ) measured at 190°C under a 2.16 kg load of 0.01 to 10.0 g/10 min; (3) A method for producing an olefin polymer having a melt flow ratio (MFR) of 30 to 250 between a melt index (MI _21.6 ) measured at 190°C under a load of 21.6 kg and a melt index (MI _2.16 ) measured under a load of 2.16 kg is provided, and satisfying the following mathematical expression 1.

[Mathematical Formula 1]

In the above mathematical formula, T1 and T2 are polymerization temperatures (℃), respectively, and MFR ₁ and MFR ₂ represent the MFR of the olefin polymer manufactured under polymerization temperature conditions of T1 and T2 (℃), respectively.

[Chemical Formula 1]

[Chemical Formula 2] [Chemical Formula 3] [Chemical Formula 4]

In the chemical formula above, l1, l2, l3, and m1 are each independently integers from 0 to 4. Preferably, l1, l3, and m1 are each 1, and l2 is each 0.

m2 and m3 are each independently integers from 0 to 2. Preferably, m2 is each 0, and m3 is each 1.

n1 and o1 are each independently integers from 0 to 5. Preferably, n1 is 1, and m1 is each independently integer from 1 to 5.

M is a transition metal in Group 4 of the periodic table. Specifically, M can be titanium (Ti), zirconium (Zr), or hafnium (Hf), and more specifically, zirconium or hafnium.

Each 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 _1-20 alkylamido or C _6-20 arylamido. Specifically, each X can independently be halogen or C _1-20 alkyl, and more specifically, can be chlorine (Cl) or methyl.

R ₁ , R ₂ , R ₅ to R ₈ , R ₁₁ , R ₁₂ are each independently a substituted or unsubstituted C _1-20 alkyl, a substituted or unsubstituted C _2-20 alkenyl, a substituted or unsubstituted C _6-20 aryl, a substituted or unsubstituted C _1-20 alkyl C _6-20 aryl, a substituted or unsubstituted C _6-20 aryl C _1-20 alkyl, a substituted or unsubstituted C _1-20 heteroalkyl, a substituted or unsubstituted C _3-20 heteroaryl, a substituted or unsubstituted C _1-20 alkylamido, a substituted or unsubstituted C _6-20 arylamido, or a substituted or unsubstituted C _1-20 silyl, wherein each of these may independently form a substituted or unsubstituted saturated or unsaturated C _4-20 ring by connecting adjacent groups. Specifically, R ₁ , R ₂ , R ₅ to R ₈ , R ₁₁ , R ₁₂ can each independently be a substituted or unsubstituted C _1-20 alkyl or a substituted or unsubstituted C _6-20 aryl.

R ₃ , R ₄ , R ₉ , R ₁₀ , R ₁₃ and R ₁₄ are each independently a substituted or unsubstituted C _1-20 alkyl, a substituted or unsubstituted C _2-20 alkenyl, a substituted or unsubstituted C _6-20 aryl, a substituted or unsubstituted C _1-20 alkyl C _6-20 aryl, a substituted or unsubstituted C _6-20 aryl C _1-20 alkyl, a substituted or unsubstituted C _1-20 heteroalkyl, a substituted or unsubstituted C _3-20 heteroaryl, a substituted or unsubstituted C _1-20 alkylamido, a substituted or unsubstituted C _6-20 arylamido, or a substituted or unsubstituted C _1-20 silyl, wherein R ₃ and R ₄ , R ₉ and R ₁₀ , R ₁₃ and R ₁₄ are each independently connected to each other and substituted or may form an unsubstituted saturated or unsaturated C _2-20 ring. Specifically, R ₃ , R ₄ , R ₉ , R ₁₀ , R ₁₃ and R ₁₄ may each independently be a substituted or unsubstituted C _1-20 alkyl, a substituted or unsubstituted C _2-20 alkenyl or a substituted or unsubstituted C _6-20 aryl.

In a specific example of the present invention, the transition metal compound of the above chemical formula 1 may be at least one of the transition metal compounds represented by the chemical formulas 1-1 to 1-10 below.

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

[Chemical Formula 1-3] [Chemical Formula 1-4]

[Chemical Formula 1-5] [Chemical Formula 1-6]

[Chemical Formula 1-7] [Chemical Formula 1-8]

[Chemical Formula 1-9] [Chemical Formula 1-10]

In the above chemical formula, Me is methyl, n -Bu is n -butyl, t -Bu is t -butyl, Ph is phenyl, and p -Tol is p -tolyl.

In a specific example of the present invention, the transition metal compound of the above chemical formula 2 may be at least one of the transition metal compounds represented by the chemical formulas 2-1 to 2-8 below, the transition metal compound of the above chemical formula 3 may be a transition metal compound represented by the chemical formula 3-1 below, and the transition metal compound of the above chemical formula 4 may be at least one of the transition metal compounds represented by the chemical formulas 4-1 to 4-2 below.

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

[Chemical Formula 2-4] [Chemical Formula 2-5] [Chemical Formula 2-6]

[Chemical Formula 2-7] [Chemical Formula 2-8] [Chemical Formula 3-1]

[Chemical Formula 4-1] [Chemical Formula 4-2]

In the chemical formula above, Me is methyl and Ph is phenyl.

In a specific embodiment 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.

In a specific embodiment of the present invention, the above catalyst may include at least one cocatalyst compound selected from the group consisting of a compound represented by the following chemical formula 5, a compound represented by the following chemical formula 6, and a compound represented by the following chemical formula 7.

[Chemical Formula 5]

In the above chemical formula 5, n is an integer greater than or equal to 2, and R _a may be a halogen atom, a C _1-20 hydrocarbon, or a C _1-20 hydrocarbon substituted with a halogen. Specifically, R _a may be methyl, ethyl, n -butyl, or isobutyl.

[Chemical Formula 6]

In the above chemical formula 6, D is aluminum (Al) or boron (B), and R _b , R _c , and R _d are each independently a halogen atom, a C _1-20 hydrocarbon group, a C _1-20 hydrocarbon group substituted with a halogen, or a C _1-20 alkoxy group. Specifically, when D is aluminum (Al), R _b , R _c , and R _d can each independently be methyl or isobutyl, and when D is boron (B), R _b , R _c , and R _d can each be pentafluorophenyl.

[Chemical Formula 7]

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

In the above chemical formula 7, L is a neutral or cationic Lewis base, [LH] ⁺ and [L] ⁺ are Brønsted acids, Z is a Group 13 element, and each A is independently a substituted or unsubstituted C _6-20 aryl group or a substituted or unsubstituted C _1-20 alkyl group. Specifically, [LH] ⁺ can be a dimethylanilinium cation, [Z(A) ₄ ] ^- can be [B(C ₆ F ₅ ) ₄ ] ^- , and [L] ⁺ can be [(C ₆ H ₅ ) ₃ C] ⁺ .

Specifically, examples of compounds represented by the above chemical formula 5 include methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, butylaluminoxane, etc., and methylaluminoxane is preferred, but is not limited thereto.

Examples of compounds represented by the above chemical formula 6 include trimethylaluminum, triethylaluminum, triisobutylaluminum, tripropylaluminum, tributylaluminum, dimethylchloroaluminum, triisopropylaluminum, tri- s -butylaluminum, tricyclopentylaluminum, tripentylaluminum, triisopentylaluminum, trihexylaluminum, trioctylaluminum, ethyldimethylaluminum, methyldiethylaluminum, triphenylaluminum, tri- p -tolylaluminum, dimethylaluminum methoxide, dimethylaluminum ethoxide, trimethylboron, triethylboron, triisobutylboron, tripropylboron, tributylboron, etc., and trimethylaluminum, triethylaluminum, and triisobutylaluminum are preferred, but are not limited thereto. It is not.

Examples of compounds represented by the above chemical formula 7 include triethylammonium tetraphenylboron, tributylammonium tetraphenylboron, trimethylammonium tetraphenylboron, tripropylammonium tetraphenylboron, trimethylammonium tetra( p -tolyl)boron, trimethylammonium tetra( o , p -dimethylphenyl)boron, trimethylammonium tetra( p -trifluoromethylphenyl)boron, tributylammonium tetrapentafluorophenylboron, N,N-diethylanilinium tetraphenylboron, N,N-diethylanilinium tetrapentafluorophenylboron, diethylammonium tetrapentafluorophenylboron, triphenylphosphonium tetraphenylboron, trimethylphosphonium 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 tetrapentafluorophenyl aluminum, N,N-diethylanilinium tetraphenyl aluminum, N,N-diethylanilinium tetrapentafluorophenyl aluminum, diethylammonium tetrapentatetraphenyl aluminum, triphenylphosphonium tetraphenyl aluminum, trimethylphosphonium tetraphenyl aluminum, tripropylammonium tetra( p -tolyl) boron, triethylammonium tetra( o , p -dimethylphenyl) boron, tributylammonium tetra( p -trifluoromethylphenyl) boron, Examples include triphenylcarbonium tetra( p -trifluoromethylphenyl)boron, triphenylcarbonium tetrapentafluorophenylboron, etc.

In a specific embodiment of the present invention, the above catalyst may further include a carrier carrying a transition metal compound, a cocatalyst compound, or both. Specifically, the carrier may carry both a transition metal compound and a cocatalyst compound.

At this time, the carrier may include a material containing a hydroxyl group on the surface, and preferably, a material having a highly reactive hydroxyl group and a siloxane group, which has been dried to remove moisture from the surface, may be used. For example, the carrier may include at least one selected from the group consisting of silica, alumina, and magnesia. Specifically, silica, silica-alumina, and silica-magnesia dried at a high temperature can be used as the carrier, and these can typically contain oxides such as Na ₂ O, K ₂ CO ₃ , BaSO ₄ , and Mg(NO ₃ ) ₂ , carbonates, sulfates, and nitrates. In addition, these may include carbon, zeolites, magnesium chloride, and the like. However, the carrier is not limited to these, and is not particularly limited as long as it can support a transition metal compound and a cocatalyst compound.

The carrier may have an average particle size of 10 to 250 μm, preferably an average particle size of 10 to 150 μm, and more preferably an average particle size of 20 to 100 μm.

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.

The specific surface area of the carrier may be 1 to 1,000 m2/g, preferably 100 to 800 m2/g, and more preferably 200 to 600 m2/g.

In a preferred embodiment of the present invention, the carrier may be silica. In this case, the silica may have a drying temperature of 200 to 900°C. The drying temperature is preferably 300 to 800°C, more preferably 400 to 700°C. If the drying temperature is below 200°C, excessive moisture content may result in a reaction between the surface moisture and the co-catalyst compound. If the drying temperature exceeds 900°C, the structure of the carrier may collapse.

The concentration of hydroxyl groups in the dried silica may 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 amount of the cocatalyst compound supported may be reduced, and if it exceeds 5 mmole/g, the problem of the catalyst component becoming deactivated may occur.

The total amount of transition metal compound supported on the carrier may be 0.001 to 1 mmole per 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 terms of maintaining the activity of the catalyst and economic efficiency.

The total amount of the cocatalyst compound supported on the carrier may be 2 to 15 mmole per 1 g of the carrier. If the ratio of the cocatalyst compound to the carrier satisfies the above range, it is advantageous in terms of maintaining the activity of the catalyst and economic efficiency.

One or more types of carriers may be used. For example, both the transition metal compound and the cocatalyst compound may be supported on one type of carrier, or the transition metal compound and the cocatalyst compound may be supported on two or more types of carriers, respectively. Furthermore, only one of the transition metal compound and the cocatalyst compound may be supported on the carrier.

As a method for supporting a transition metal compound and/or a cocatalyst compound that can be used as a catalyst for olefin polymerization, a physical adsorption method or a chemical adsorption method can be used.

For example, the physical adsorption method may be a method of contacting a solution containing a dissolved transition metal compound with a carrier and then drying it, a method of contacting a solution containing a dissolved transition metal compound and a promoter compound with a carrier and then drying it, or a method of contacting a solution containing a dissolved transition metal compound with a carrier and then drying it to produce a carrier loaded with a transition metal compound, and separately a method of contacting a solution containing a dissolved promoter compound with a carrier and then drying it to produce a carrier loaded with a promoter compound, and then mixing them.

The chemical adsorption method may be a method of first supporting a co-catalyst compound on the surface of a carrier and then supporting a transition metal compound on the co-catalyst compound, or a method of covalently bonding a catalyst compound with a functional group on the surface of the carrier (for example, a hydroxyl group (-OH) on the surface of silica in the case of silica).

In a specific embodiment of the present invention, the olefin polymer may be polymerized by, but is not limited to, polymerization reactions such as free radical, cationic, coordination, condensation, and addition.

As one embodiment of the present invention, the olefin polymer can be produced by a gas phase polymerization method, a solution polymerization method, a slurry polymerization method, etc. Preferably, the polymerization of the olefin monomer can be performed by gas phase polymerization, and specifically, the polymerization of the olefin monomer can be performed in a gas phase fluidized bed reactor.

When an olefin polymer is produced by a solution polymerization method or a slurry polymerization method, examples of solvents that can be used include, but are not limited to, C _5-12 aliphatic hydrocarbon solvents such as pentane, hexane, heptane, nonane, decane, and isomers thereof; aromatic hydrocarbon solvents such as toluene and benzene; hydrocarbon solvents substituted with chlorine atoms such as dichloromethane and chlorobenzene; and mixtures thereof.

As one embodiment of the present invention, the polymerization of the olefin monomer may be performed in a batch or continuous manner. Preferably, the polymerization of the olefin monomer may be performed continuously.

In a specific embodiment of the present invention, the olefin polymer may 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.

Here, the olefin monomer is at least one selected from the group consisting of C _2-20 alpha-olefin, C _1-20 diolefin, C _3-20 cycloolefin, and C _3-20 cyclodiolefin.

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 type of the olefin monomer exemplified above, or a copolymer containing two or more types.

In an exemplary embodiment, the olefin polymer may be a copolymer of ethylene and a C _3-20 alpha-olefin. Preferably, the olefin polymer may be linear low-density polyethylene in which the olefin monomer is ethylene and the olefin comonomer is 1-hexene.

In this case, the ethylene content is preferably 55 to 99.9 wt%, more preferably 90 to 99.9 wt%. The alpha-olefin comonomer content is preferably 0.1 to 45 wt%, more preferably 0.1 to 10 wt%.

The olefin polymer obtained by the above manufacturing method according to an embodiment of the present invention has (1) a density of 0.915 to 0.985 g/cm3; (2) a melt index (MI _2.16 ) measured at 190°C under a load of 2.16 kg of 0.01 to 10.0 g/10 min; and (3) a melt flow ratio (MFR) of 30 to 250 between a melt index (MI _21.6 ) measured at 190°C under a load of 21.6 kg and a melt index (MI _2.16 ) measured at a load of 2.16 kg.

In a specific embodiment of the present invention, the olefin polymer has a density of 0.915 to 0.985 g/cm3. Preferably, the density of the olefin polymer may be 0.920 to 0.980 g/cm3.

In a specific embodiment of the present invention, the olefin polymer has a melt index (MI _2.16 ) of 0.01 to 10.0 g/10 min, measured at 190°C under a 2.16 kg load. Preferably, the melt index of the olefin polymer may be 0.01 to 5.0 g/10 min, measured at 190°C under a 2.16 kg load.

In a specific example of the present invention, the olefin polymer has a melt flow ratio (MFR) of 30 to 250 between a melt index (MI _21.6 ) measured at 190°C under a load of 21.6 kg and a melt index (MI _2.16 ) measured under a load of 2.16 kg. Preferably, the MFR may be 30 to 230.

The above manufacturing method according to an embodiment of the present invention has a polymerization temperature (℃) and an MFR of an olefin polymer manufactured therefrom that satisfies the following mathematical expression 1.

[Mathematical Formula 1]

In the above mathematical formula, T1 and T2 are polymerization temperatures (℃), respectively, and MFR ₁ and MFR ₂ represent the MFR of the olefin polymer manufactured under polymerization temperature conditions of T1 and T2 (℃), respectively.

Example

Hereinafter, the present invention will be described in more detail through examples. However, the following examples are intended only to illustrate the present invention, and the scope of the present invention is not limited to these examples.

Manufacturing example

Transition metal compounds used in the examples were purchased from sPCI or MCN, silica (XPO-2402) was purchased from Grace, and cocatalyst compounds were purchased from Lake Materials. All materials were used without further purification unless otherwise stated.

Manufacturing example 1

8.7 g of a 10% toluene solution of methylaluminoxane was added to 29 mg of the transition metal compound of Chemical Formula 1-1, 7 mg of the transition metal compound of Chemical Formula 2-1, and 15 mg of the transition metal compound of Chemical Formula 4-1, and stirred at room temperature for 1 hour. At this time, the molar ratio of the transition metal compound of Chemical Formula 1-1: the transition metal compound of Chemical Formula 2-1: the transition metal compound of Chemical Formula 4-1 was 10:50:40.

The reaction solution was poured into 2 g of silica (XPO-2402), and 15 ml of toluene was additionally added, followed by stirring at 75°C for 3 hours. The supported catalyst was washed three times with 10 ml of toluene, and dried in a vacuum at 60°C for 1 hour to obtain 2.3 g of the supported catalyst in powder form.

Manufacturing example 2

2.0 g of a supported catalyst in powder form was obtained in the same manner as in Preparation Example 1, except that 15 mg of a transition metal compound of Chemical Formula 2-7 was used instead of the transition metal compound of Chemical Formula 2-1.

Manufacturing example 3

2.2 g of a supported catalyst in powder form was obtained in the same manner as in Preparation Example 1, except that 17 mg of a transition metal compound of Chemical Formula 3-1 was used instead of the transition metal compound of Chemical Formula 2-1.

Manufacturing example 4

1,057 g of a 10% toluene solution of methylaluminoxane was added to 2.4 g of the transition metal compound of Chemical Formula 1-1, 1.7 g of the transition metal compound of Chemical Formula 2-7, and 2.1 g of the transition metal compound of Chemical Formula 4-1, and stirred at room temperature for 1 hour. At this time, the molar ratio of the transition metal compound of Chemical Formula 1-1: the transition metal compound of Chemical Formula 2-7: the transition metal compound of Chemical Formula 4-1 was 10:50:40.

The reaction solution was poured into 250 g of silica (XPO-2402), and 300 ml of toluene was additionally added, followed by stirring at 75°C for 3 hours. The supported catalyst was washed once with 500 ml of toluene, and dried in a vacuum at 60°C for 16 hours to obtain 352 g of a supported catalyst in powder form.

Manufacturing example 5

A catalyst currently used in the commercial production of polyolefins (Univation, 2010EN; Comparative Example 1) was used.

Manufacturing example 6

355 g of a supported catalyst in powder form was obtained in the same manner as in Manufacturing Example 4, except that 7.9 g of the transition metal compound of Chemical Formula 1-1 was used alone.

Example 1~3 and Comparative example 1~2

Olefin polymers were prepared using the supported catalysts obtained in Preparation Examples 1 to 3 and 5 to 6, respectively, using a slurry polymerization reactor. 30 mg of the supported catalyst and 1 L of hexane were charged into the reactor, and 0.6 mL of 1 M triisobutyl aluminum (TiBAL) was added as a scavenger. The pressure of ethylene was maintained at 14 kgf/cm2, 10 mL of 1-hexene was initially added, and 100 mL of hydrogen was initially added, followed by continuous addition of 10 mL per minute. Polymerization was performed for 1 hour at the reaction temperature shown in Table 1 below.

catalyst Polymerization temperature (℃) Catalytic activity (gPE/gCat·hr) Example 1-1 Manufacturing Example 1 90 1,650 Example 1-2 80 1,950 Example 2-1 Manufacturing Example 2 90 4,200 Example 2-2 80 2,950 Example 3-1 Manufacturing Example 3 90 1,900 Example 3-2 80 2,700 Comparative Example 1-1 Manufacturing Example 5 90 3,320 Comparative Example 1-2 80 5,200 Comparative Example 2-1 Manufacturing Example 6 90 6,500 Comparative Example 2-2 80 4,030

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

(1) Density

Measured according to ASTM D1505.

(2) Melt index and melt flow rate (MFR)

According to ASTM D 1238, the melting index was measured at 190℃ under a load of 21.6 kg and a load of 2.16 kg, respectively, and the ratio (MI _21.6 /MI _2.16 ) was obtained.

(3) Molecular weight and molecular weight distribution

It was measured using 3D gel permeation chromatography-FTIR (GPC-FTIR) at 170℃.

(4) Thermal characteristics

Measurements were made using a differential scanning calorimeter (DSC, device name: DSC 2920, manufacturer: TA Instrument). Specifically, the polymer was heated to 200°C, maintained at that temperature for 5 minutes, cooled to 20°C, and then increased again, with the temperature rising and falling rates each controlled to 20°C/min.

I _2.16 MFR Mw Mw/Mn Tm(℃) Tc(℃) Crystallinity
(%) density
(g/ml) Example 1-1 0.30 64.2 153,203 17.4 132.3 117.6 77.0 0.962 Example 1-2 0.22 34.7 137,222 7.3 122.9 109.6 56.5 0.935 Example 2-1 0.01 201.7 278,291 15.5 124.5 110.1 47.1 0.931 Example 2-2 0.06 126 124,755 25.5 127.7 115.7 60.9 0.940 Example 3-1 0.06 60.0 282,384 7.0 125.0 111.4 50.3 0.927 Example 3-2 0.09 73.7 174,517 3.0 127.0 114.1 53.0 0.939 Comparative Example 1-1 1.15 71.4 106,876 5.6 130.2 116.4 70.4 0.952 Comparative Example 1-2 0.83 72.7 84,597 4.9 130.2 118.1 68.5 0.948 Comparative Example 2-1 1.83 24.7 75,529 2.5 129.5 115.1 64.4 0.946 Comparative Example 2-2 4.21 25.3 99,724 5.2 130.4 115.6 69.6 0.951

As can be seen from Table 2 above, the method for producing an olefin polymer according to an embodiment of the present invention can relatively significantly change the properties of the olefin polymer produced using the method, particularly the MFR and PDI (Mw/Mn), depending on the polymerization temperature. On the other hand, when the catalyst of the comparative example was used, the change in the MFR and PDI (Mw/Mn) of the olefin polymer depending on the polymerization temperature was not significant.

Example 4 and Comparative example 3

Olefin polymers were produced in a pilot gas-phase fluidized bed reactor using the supported catalysts obtained in Manufacturing Examples 4 and 6. The catalyst input was adjusted to maintain a constant resin production rate of 8 kg/hr, and the ethylene partial pressure was maintained at approximately 14 kgf/cm2. After operating for more than 12 hours, the properties of the produced olefin polymers were determined. The results are shown in Table 3 below.

Example 4-1 Example 4-2 Comparative Example 3-1 Comparative Example 3-2 catalyst Manufacturing Example 4 Manufacturing Example 4 Manufacturing Example 6 Manufacturing Example 6 Ethylene partial pressure (kgf/㎠) 14.13 13.92 14.02 14.83 Reaction temperature (℃) 90.26 80.24 91.03 83.22 Catalytic activity (gPE/gCat·hr) 6,984 4,211 4,315 5,417 MI _2.16 0.57 0.61 1.01 1.02 MFR 21.25 24.46 16.4 15.9 Density (g/ml) 0.9411 0.9417 0.9198 0.9195

Even in the case of continuous polymerization using a gas-phase fluidized bed reactor, the method for producing an olefin polymer according to an embodiment of the present invention can relatively significantly change the physical properties of the olefin polymer produced using the method, particularly the MFR and PDI (Mw/Mn), depending on the polymerization temperature.

Polymerization method Example 1 Lab batch slurry 0.22 Example 2 Lab batch slurry 0.15 Example 3 Lab batch slurry 0.14 Comparative Example 1 Lab batch slurry 0.06 Comparative Example 2 Lab batch slurry 0.06 Example 4 Gas-phase fluidized bed reactor 0.11 Comparative Example 3 Gas-phase fluidized bed reactor 0.03

As confirmed in Table 4, for the embodiments of the present invention satisfying mathematical formula 1, significant changes in molecular weight distribution were observed depending on the polymerization temperature in both the lab batch slurry reaction and the gas-phase fluidized bed reactor. Specifically, for the embodiments of the present invention, it can be confirmed that the value of mathematical formula 1 is approximately 2 to 4 times larger than that of the comparative example.

Claims (10)

A method for producing an olefin polymer, comprising: polymerizing an olefin monomer at a polymerization temperature of 75 to 95°C in the presence of a hybrid catalyst comprising at least one first transition metal compound represented by any of the following chemical formulae 1-1, 1-4, 1-5, 1-7 to 1-10; at least one second transition metal compound selected from compounds represented by any of the following chemical formulae 2-1, 2-2, 2-4 to 2-8 and 3-1; and at least one second transition metal compound selected from compounds represented by any of the following chemical formulae 4-1 and 4-2; wherein the olefin polymer has (1) a density of 0.915 to 0.985 g/cm3; (2) a melt index (MI _2.16 ) measured at 190°C under a load of 2.16 kg of 0.01 to 10.0 g/10 min; (3) A method for manufacturing an olefin polymer having a melt flow ratio (MFR) of 30 to 250 between a melt index (MI _21.6 ) measured at 190°C with a load of 21.6 kg and a melt index (MI _2.16 ) measured at a load of 2.16 kg, and satisfying the following mathematical formula 1:
[Mathematical Formula 1]

In the above mathematical formula, T1 and T2 are polymerization temperatures (℃), respectively, and MFR ₁ and MFR ₂ represent the MFR of olefin polymers manufactured under polymerization temperature conditions of T1 and T2 (℃), respectively.

[Chemical Formula 1-1] [Chemical Formula 1-4]

[Chemical Formula 1-5]

[Chemical Formula 1-7] [Chemical Formula 1-8]

[Chemical Formula 1-9] [Chemical Formula 1-10]

In the chemical formula above, Me is methyl, n -Bu is n -butyl, t -Bu is t -butyl, Ph is phenyl, and p -Tol is p -tolyl.
[Chemical Formula 2-1] [Chemical Formula 2-2]

[Chemical Formula 2-4] [Chemical Formula 2-5] [Chemical Formula 2-6]

In the chemical formula above, Me is methyl,
[Chemical Formula 2-7] [Chemical Formula 2-8] [Chemical Formula 3-1]


[Chemical Formula 4-1] [Chemical Formula 4-2]

In the chemical formula above, Ph is phenyl. delete delete A method for producing an olefin polymer, wherein the catalyst comprises at least one cocatalyst selected from the group consisting of a compound represented by the following chemical formula 5, a compound represented by the following chemical formula 6, and a compound represented by the following chemical formula 7.
[Chemical Formula 5]

[Chemical Formula 6]

[Chemical Formula 6]
[LH] ⁺ [Z(A) ₄ ] ^- or [L] ⁺ [Z(A) ₄ ] ^-
In the above chemical formula 5, n is an integer greater than or equal to 2, R _a is a halogen atom, a C _1-20 hydrocarbon group, or a C _1-20 hydrocarbon group substituted with a halogen,
In the above chemical formula 6, D is aluminum (Al) or boron (B), R _b , R _c and R _d are each independently a halogen atom, a C _1-20 hydrocarbon group, a C _1-20 hydrocarbon group substituted with a halogen or a C _1-20 alkoxy group,
In the above chemical formula 7, L is a neutral or cationic Lewis base, [LH] ⁺ and [L] ⁺ are Bronsted acids, Z is a Group 13 element, and A is each independently a substituted or unsubstituted C _6-20 aryl group or a substituted or unsubstituted C _1-20 alkyl group. A method for producing an olefin polymer, wherein the catalyst further comprises a carrier supporting a transition metal compound, a cocatalyst compound, or both. A method for producing an olefin polymer, wherein the carrier comprises at least one selected from the group consisting of silica, alumina, and magnesia. A method for producing an olefin polymer, wherein in claim 5, the total amount of the 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 cocatalyst compound supported on the carrier is 2 to 15 mmole based on 1 g of the carrier. A method for producing an olefin polymer in claim 1, wherein the olefin polymer is a copolymer of an olefin monomer and an olefin comonomer. A method for producing an olefin polymer in claim 8, wherein the olefin monomer is ethylene, and the olefin comonomer is at least one selected from the group consisting of 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. A method for producing an olefin polymer in claim 9, wherein the olefin polymer is a linear low-density polyethylene in which the olefin monomer is ethylene and the olefin comonomer is 1-hexene.