KR20090076422A - Method of polymerizing olefins - Google Patents

Abstract

A method of polymerizing olefins is provided to suppress production of corpuscles with using the inexpensive catalyst, to improve productivity and to reduce the density of a polymer with using a small amount of alpha-olefin comonomer. A method of polymerizing olefins comprises the steps of: performing gas-phase polymerization of at least one olefin in the presence of an olefin polymerization catalyst; removing polymerization heat with passing the olefin through a polymerization region; and supplying circulation gas to maintain an equilibrium state of the polymerization region. The circulation gas is supplied in a liquid form to a polymerization reactor. The olefin polymerization catalyst comprises an organometallic compound represented by chemical formula 1: M^1R^1_lR^2_mR^3_n or R^2_mR^3_nM^1R^1_l-Q-R^1_lM^1R^2_mR^3_; aluminoxane; and an organic transition metal compound represented by chemical formula 2: M^2R^4_pX_q.

Description

Polymerization method of olefins {Method of polymerizing olefins}

The present invention relates to a method for the polymerization of olefins, and more particularly, to a method for continuously polymerizing olefins in the presence of an olefin polymerization catalyst.

Recently, various catalyst systems for olefin polymerization have been developed. Despite the various advantages, the industrial use of recently developed olefin polymerization catalyst systems has several disadvantages associated therewith. One of them is that fouling is often found in polymerization reactors when the catalyst system is used in industrial plants. This adversely affects the preparation of polymers with good particle morphology and bulk density. Several methods have been reported to reduce reactor fouling or to improve polymer product morphology. For example, there is a method of supporting a catalyst component on a porous carrier or prepolymerizing the catalyst system. In general, the prepolymerization treatment can give advantages such as reduced fine powder formation, good particle properties, high bulk density and improved particle flowability. Korean Patent Application No. 2002-0088224 relates to a prepolymerization method of a metallocene catalyst system, which method prepolymerizes the supported olefin polymerization catalyst system in the presence of an olefin monomer, with or without an impurity remover and an antistatic agent. Steps.

Polymerization methods for olefins using metallocene catalysts are well known in the art. This method uses a catalyst system comprising a metallocene compound, wherein the metallocene compound is defined as an organometallic coordination compound in which a cyclopentadienyl derivative is coordinated with a transition metal. As metallocene compounds, crosslinked or uncrosslinked biscyclopentadienyl Group 4 metal compounds are particularly representative, many of which are useful for gas phase polymerization or slurry polymerization, in which the use of supported catalysts is typical. It is also known to use multiple metallocenes in a single polymerization reactor. For example, US Pat. No. 4,808,561 describes a process for the polymerization of ethylene and other olefins, in particular copolymers of higher alpha-olefins and / or diolefins and / or cyclic olefins in the presence of homopolymers and metallocene catalysts of ethylene. have. U. S. Patent 5,405, 922 describes a gas phase olefin polymerization process using a gas phase fluidized bed polymerization reactor operating in condensed form, and in Tables 1 to 4 disclose ethylene polymers having a density of 0.9168 to 0.9222 g / cc. have. Korean Patent Application No. 2005-7025441 discloses an olefin polymerization method including a method of prepolymerization in a loop reactor as an olefin polymerization method using a metallocene catalyst.

Ethylene polymerization with metallocene catalysts is well known in the art, but there are certain problems with these methods. That is, since metallocene is very expensive compared to the transition metal halogenated polymerization catalyst, if the olefin polymerization productivity is low, the method is not economical. In addition, like other low activity catalysts, metallocene catalysts exhibiting low productivity may cause operation interruption due to abnormal phenomenon during the polymerization process. In particle form polymerization methods such as gas phase and slurry polymerization methods, low productivity generally results in reduced average particle diameter (APS) and high particulate content. On the circulating gas loop of the fluidized bed gas phase reactor, microparticles are easily produced, contaminating the circulating gas cooler and reactor distributor plates, thereby preventing effective reactor cooling and fluidization. Excessive amounts of microparticles can render the reactor inoperable, resulting in lost productivity and increased costs, requiring downtime and cleaning. On the contrary, when the activity of the catalyst is too high, as the local reaction activity of the catalyst increases, particle crushing may occur and reaction heat out of control may occur, which may cause a high amount of particulates, thereby controlling the reaction heat. It is indispensable.

In addition, it is preferable to use catalysts that exhibit good α-olefin incorporation when slurries and gas phase processes are used to produce ethylene / α-olefin copolymers of desired density. When using a catalyst that exhibits good α-olefin incorporation, relatively small α-olefins need to be present for a given ethylene concentration in the reactor to achieve the desired polymer density. For example, highly incorporated catalysts can produce low density polyethylene having a low ratio of α-olefin / ethylene reactants. This is because high concentrations of α-olefins produce high concentrations of dissolved α-olefins in the polymer particles, making the particles tacky and prone to aggregation, agglomeration and contamination. This problem is particularly acute when producing polymers having a density of less than about 0.915 g / cc. The ability to use less α-olefins allows for a high amount of condensed liquid to be used during condensed form operation, which in turn allows for high production rates. Thus, there remains a need for an ethylene polymerization process that produces polymers of a given density using the lowest possible amount of α-olefin comonomers.

It is therefore an object of the present invention to provide a process for the polymerization of olefins which can reduce the occurrence of fouling in the polymerization reactor.

Another object of the present invention is to provide a polymerization method of olefins which can suppress the formation of fine particles and improve productivity while using a low cost catalyst.

It is a further object of the present invention to provide a process for the polymerization of olefins which can reduce the density of the polymer while using small amounts of α-olefin comonomers.

In order to achieve the above object, the present invention, an organometallic compound; Aluminoxanes; And gas phase polymerizing one or more olefins in the presence of a catalyst for olefin polymerization including an organic transition metal compound, removing the heat of polymerization while passing through the polymerization zone where the olefin is polymerized, and maintaining the equilibrium state of the polymerization zone. Supplying a circulating gas, wherein the circulating gas is supplied to the polymerization reactor in a liquid state provides a polymerization method of olefin.

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

Catalysts used in the polymerization method of the olefin according to the present invention, an organometallic compound represented by the formula (1); Aluminoxanes; And it includes an organic transition metal compound represented by the formula (2).

[Formula 1]

M ¹ R ¹ _l R ² _m R ³ _n or R ² _m R ³ _n M ¹ R ¹ _l -QR ¹ _l M ¹ R ² _m R ³ _n

In Formula 1, M ¹ is a 2A, 2B or 3B group element of the periodic table. R ¹ is a substituted or unsubstituted cyclic hydrocarbon group having 5 to 30 carbon atoms having two or more conjugated double bonds, R ² and R ³ are each independently a hydrocarbon group having 1 to 24 carbon atoms, and l is an integer of 1 or more , m and n are each independently an integer of 0 to 2, l + m + n is equal to the valence of M ¹ , Q is (CR ⁵ ₂ ) _b , (SiR ⁵ ₂ ) _b , connecting R ¹ (GeR ⁵ ₂ ) _b is a divalent group selected from _b , NR ⁵ or PR ⁵ , wherein the substituents R ⁵ are each independently a hydrogen atom, an alkyl radical having 1 to 20 carbon atoms, a cycloalkyl radical having 3 to 20 carbon atoms, or carbon atoms An alkenyl radical of 1 to 20, an aryl radical of 6 to 20 carbon atoms, an alkylaryl radical of 7 to 20 carbon atoms, or an arylalkyl radical of 7 to 20 carbon atoms, b is 1 to 4, and Q is (CR ⁵ ₂ ) _b , (SiR ⁵ ₂ ) _b , (GeR ⁵ ₂ ) _b , _two carbon atoms connected to carbon (C), silicon (Si), and germanium (Ge) Substituents R ⁵ may be linked to each other to form a ring having 2 to 7 carbon atoms.

[Formula 2]

In Formula 2, M ² is titanium (Ti), zirconium (Zr) or hafnium (Hf), R ⁴ is a substituted or unsubstituted cyclic hydrocarbon group having 5 to 30 carbon atoms having two or more conjugated double bonds. , X is a halogen atom, p is an integer of 0 or 1, q is an integer of 3 or 4, p + q is equal to the valence of the metal M ² . The catalyst for olefin polymerization used in the present invention is disclosed in detail in Korean Patent Application No. 10-2005-124863, and all the contents of the Korean Patent Application No. 10-2005-124863 are incorporated herein by reference. The olefins used for the said polymerization can be used individually or in mixture of 2 or more types. Ethylene is preferable as the olefin, and other α-olefin monomers (comonomers) may be mixed and used as necessary. The other alpha-olefins can prevent yield increase and reactor fouling, and preferred examples of the other α-olefins include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene The addition ratio (weight ratio) of other alpha-olefins to ethylene can be preferably 1: 0.01-10. The solvent of the polymerization reaction is propane, butane, pentane, hexane, octane, decane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, dichloromethane, chloroethane, 1,2-dichloro Ethane, chlorobenzene, etc. can be illustrated, These solvent can also be mixed and used in fixed ratio. In the polymerization or copolymerization of the olefin according to the present invention, the amount of the organic transition metal compound is not particularly limited, but in the reaction system used for polymerization, the central metal concentration of the organic transition metal compound is 10 ^-8 to 10 ¹ mol /. that the ℓ, and preferably, less than 10 ^-7 to 10 ^-2 ㏖ / ℓ is more preferred.

The polymerization of the polyolefin according to the present invention can be carried out in a series of polymerization reactors in which a prepolymerization reactor and a gas phase polymerization reactor are continuously installed. 1 is a schematic diagram of a polymerization reactor for polymerizing a polyolefin according to one embodiment of the present invention. In FIG. 1, an example in which two prepolymerization reactors 2 and two gas phase polymerization reactors 5 and 8 are connected in a line is illustrated, but the prepolymerization may be omitted as necessary, and may be omitted. Two or more gas phase polymerization reactors may be used. As shown in FIG. 1, the dilution hydrocarbon and the pretreated or untreated olefin polymerization catalyst are introduced into the prepolymerization reactor 2 through the raw material supply pipe 1. At this time, ethylene alone or ethylene and alpha olefin may be mixed and introduced through the raw material supply pipe (1), hydrogen and impurity remover, antistatic agent may be added together. The prepolymerization reactor 2 may be in the form of a continuous stirring or loop type reactor. Prepolymerization in the prepolymerization reactor (2) is carried out at 0 to 80 ℃, polyolefin polymerization of 1 to 1,000 times the catalyst mass is carried out. The formed prepolymer is introduced into the first gas phase polymerization reactor (5) through the first conveying pipe (3), and through the first branch pipe (4) formed in the first conveying pipe (3), further ethylene, alpha olefin Hydrocarbons for dilution (eg propane), molecular weight regulators (eg hydrogen), impurity removers and antistatic agents can be introduced. In the first gas phase polymerization reactor (5), a polymer is formed under constant reaction conditions, and the polymer is transferred to the second gas phase polymerization reactor (8) through the second transfer pipe (6). In this case, additional ethylene, alpha olefin, dilution hydrocarbon (for example, propane), molecular weight regulator (for example, hydrogen), impurity remover, and the like are provided through the second branch pipe (7) formed in the second conveying pipe (6). Antistatic agents may be introduced. Propane, a dilution hydrocarbon, is introduced into each polymerization reactor 5, 8 at a flow rate of, for example, 100 kg / h to 10,000 kg / h. In the second gas phase polymerization reactor (8), the polymer polymerized under constant reaction conditions is transferred to a post-treatment process (steamer, dryer) through the discharge pipe (9).

The prepolymer formed in the continuous prepolymerization reactor 2 may be an α-olefin homopolymer or copolymer. Ethylene is generally used as the α-olefin monomer for prepolymerization, and other olefin monomers may be mixed and used as necessary. In the prepolymerization step of the present invention, additional use of other alpha-olefins in combination with ethylene is preferred as it can prevent yield increase and reactor fouling. Preferred examples of the other α-olefin may be propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and the input ratio (weight ratio) of other alpha-olefins to ethylene is preferably Is 1: 0.01 to 10. In a preferred embodiment of the invention, the prepolymer has a yield of 1 to 1000 g-polymer / g-catalyst and the continuous prepolymerization reaction temperature is preferably 0 to 80 ° C. Suitable diluent hydrocarbon solvents for use during continuous prepolymerization include inert hydrocarbons such as ethane, propane, isobutane, isopentane, hexane and the like, and also include inert gases such as nitrogen, argon and the like. The solvent is generally chosen not to interact with the supported catalyst system. Preferred examples of the impurity remover include aluminum alkyls such as trimethylaluminum (TMA), triethylaluminum (TIBAL), triisobutylaluminum (TIBAL), and trinomaloctyl aluminum (TNOAL), and diethyl zinc (DEZ) and dimethyl. Metal alkyls, such as magnesium (DMM), diethyl magnesium (DEM), and ethyl methyl magnesium (MEM), can be illustrated.

In the polymerization reactor shown in FIG. 1, the polymer of the first gas phase polymerization reactor 5 is introduced into the second gas phase polymerization reactor 8 of the same or different composition, polymerized, and then sent to a post treatment process. In the polymerization process of the present invention, the polymer produced in the first gas phase polymerization reactor 5 and the second gas phase polymerization reactor 8 generally has a melt index E of 0.001 to 10,000 g / 10 min, preferably 0.001 to 1,000 g / 10 min, bulk density is 0.36 to 0.45 g / cc, density is 0.860 to 0.970 g / cm ³ . The first and second gas phase polymerization reactors 5 and 8 are in a series of continuous flows, and the resulting polymers of the two reactors 5 and 8 have a similar melt index E and melt flow rate, or a first gas phase. The melt index E of the polymer produced in the polymerization reactor 5 may have a value of 5 g / 10 minutes or more, and the melt index E of the polymer produced in the second gas phase polymerization reactor 8 may have a value of 0.5 g / 10 minutes or less. In addition, the melt index of the polymer produced in the two reactors 5 and 8 may be changed. The melt flow ratio when the melt index E value of the primary gas phase polymer is low, the secondary gas phase polymer has a high value, and when the melt index E value of the primary gas phase polymer is high and the secondary gas phase polymer has a low value, The polymers of the two reactors are larger than when they have the same or similar melt index, and range from approximately 20 to 1000. When manufacturing the final product film, the polymer with a high melt flow ratio is mixed with a high molecular weight polymer and a low molecular weight polymer, and thus has excellent tensile strength and impact strength, which are characteristic of the high molecular weight, and has excellent processability due to the low molecular weight polymer. have.

2 is a schematic view of a fluidized bed gas phase polymerization reactor suitable for the polymerization of polyolefins according to the present invention. In the fluidized-bed gas phase polymerization reactor 20 shown in FIG. 2, the circulating gas is discharged to the outside through the gas discharge pipe 10, and the circulated gas discharged to the outside is transferred to the cooling water and steam in the tube-type heat exchanger 12. By heating or cooling, the gas is introduced into the gas phase polymerization reactor 20 again through the gas inlet pipe 14. Gas introduced into the gas phase polymerization reactor 20 removes the heat of polymerization while passing through the polymerization zone 16 where the polymer is polymerized, and the polymerization zone 16, that is, the equilibrium state of the fluidized bed in which the polymerization reaction is performed. Keep it. The circulating gas is forcedly circulated by the compressor 18 mounted on the path of the gas inlet pipe 14, and an enlarged region 19 is formed at the upper portion of the gas phase polymerization reactor 20, thereby lowering the rising speed of the fine powder. By doing so, the fine powder generated during the polymerization is prevented from entering the heat exchanger 12 and the compressor 18. Examples of the circulating gas include propane, butane, pentane, hexane, octane, decane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, dichloromethane, chloroethane and 1,2-dichloroethane , Chlorobenzene and the like, and another preferred example may be propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and may be used by mixing them in a certain ratio. have. The temperature control of the gas phase polymerization reactor 20 is performed by measuring the gas temperature in the gas discharge pipe 10 and the gas inlet pipe 14, and thereby adjusting the heat exchanger 12. According to the polymerization method of the present invention, if fouling and agglomeration phenomenon inside the reactor are suppressed, the temperature control range is small, and stable operation is possible. The temperature control range means a temperature change range measured at the inlet of the gas discharge pipe 10 of FIG. 2, and the temperature control range that can be operated is within ± 1 ° C. FIG. If the temperature is out of the proper temperature control range, due to fouling and agglomeration of the polymer, the produced polymer agglomerates accumulate, making normal operation difficult. The density of the circulating gas measured in the enlarged region 19 of FIG. 2 is preferably 10 kg / m ³ to 50 kg / m ³ , and the flow rate of the circulating gas in the polymerization region 16 is 0.1 m / sec to 1.5 m / sec. It is preferable.

3 is a schematic view of a liquid direct injection fluidized-bed gas phase polymerization reactor particularly suitable for the polymerization of polyolefins according to the present invention. As mentioned above, the reaction heat control is important for the suppression of the production of microparticles, and in the present invention, by introducing a hydrocarbon in a liquid state to suppress the generation of the microparticles, this is to use the latent heat (Heat of Vaporization) of the liquid, polymerization Part of the heat of reaction can be efficiently removed through the contact of the liquid with the polymer by injecting the liquid at this intensely occurring point. As shown in FIG. 3, in the liquid direct injection fluidized-bed gas phase polymerization reactor 21, the circulating gas is discharged to the outside through the gas discharge pipe 22, compressed and cooled, and then stored in the liquid storage drum 23. do. The circulating gas stored in the liquid state is pressurized while passing through the pump 24 and is introduced through the pipe 25 directly connected to the gas phase polymerization reactor 21. The position at which the circulating gas in the liquid state is introduced is a reaction region in which the reactants are vigorously polymerized. In the polymerization method of the polyolefin according to the present invention, the circulating gas is uniformly divided into three portions on a plane perpendicular to the traveling path of the circulating gas, that is, the direction in which the gas discharge pipe 22 is formed. It is preferred to be introduced.

4 is a cross-sectional view taken along line A of the reactor shown in FIG. 3 as a view for explaining a supply path of the circulating gas in the polymerization of the polyolefin according to the present invention. As shown in FIG. 4, the circulating gas is preferably supplied to the cylindrical reactor 21 on a plane parallel to the ground, that is, perpendicular to the direction in which the reactor 21 is installed, and uniformly divided into three portions. Divided into 100 to 140 degrees, preferably 110 to 130 degrees, and most preferably at three points at an angle of 120 degrees (in the direction indicated by the arrow in FIG. 4), and merged with each other at the center of the reactor 21. It is preferably supplied in form. Here, when the angle between the divided circulating gas is out of the range, there is a fear that stable operation is difficult due to the occurrence of reactor fouling. The circulating gas is supplied to the reactor 21 in a liquid state. Examples of the circulating gas include propane, butane, pentane, hexane, octane, decane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, dichloromethane, chloroethane and 1,2-dichloroethane , Chlorobenzene and the like, and another preferred example may be propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and may be used by mixing them in a certain ratio. It may be supplied with the reactant ethylene.

As described above, the polymerization method of the olefin according to the present invention can not only effectively suppress the occurrence of fouling in the polymerization reactor, but also suppress the formation of fine particles and improve productivity while using a low-cost catalyst. There is an advantage. In addition, the polymerization method of the present invention can reduce the density of the polymer while using a small amount of α-olefin comonomer.

Hereinafter, the present invention will be described in more detail with reference to Examples. The following examples illustrate the present invention and the present invention is not limited by the following examples. In the following examples, the melt index (MI: Melt Index) and HLMI (High Load Melt Index) of the polymer were measured according to ASTM D1238, and the density (density) of the polymer was measured according to ASTM D1505.

Example 1

A. Preparation of Catalyst

In a nitrogen atmosphere, 2.52 kg of indenylaluminum diethyl (Ind-AlEt ₂ ) and 220 liters of methylaluminoxane (MAO, Albemarle, 10% toluene solution) were added to a 1,000-liter flask, followed by mixing for 60 minutes at room temperature. It was. After the stirring was terminated, the mixed solution was transferred to a reaction tank containing 970 g of zirconium chloride (ZrCl ₄ ), and the mixture was reacted for 60 minutes to prepare a catalyst solution. 40 kg of silica (ES70Y, Ineos, Inc.) calcined at 250 ° C. was added to the prepared catalyst solution, followed by ultrasonication for 1 hour, and then the supernatant was removed. Next, the remaining solid particles were washed five times with hexane and then dried in vacuo to prepare a supported catalyst of free flowing solid powder.

B. Slurry Continuous Prepolymerization

The slurry continuous prepolymerization process was carried out in a continuous stirred prepolymerization reactor. The supported catalyst was constantly added at 3 kg / h, the reactants were 450 kg / h ethylene and 1-hexene at 75 kg / h as alpha-olefins, and hydrogen, a molecular weight regulator, was mixed at 1 g / h. The polymerization reaction was carried out at 50 ° C.

C. Vapor Phase Polymerization

The gas phase polymerization process was carried out in two fluidized bed reactors. The fluidized bed consists of polymer granules and ethylene, hydrogen, butene, hexene and propane were introduced over the reactor bed into the recycle gas line. Each flow rate of ethylene, hydrogen, and copolymer was adjusted to maintain a fixed compositional target. Ethylene concentration was adjusted to maintain a constant ethylene partial pressure. Hydrogen was adjusted to maintain a constant molar ratio of hydrogen to ethylene. All gas concentrations were measured by on-line gas chromatograph to ensure a relatively constant composition in the recycle stream. The reaction bed where the polymer particles grow is maintained fluidized by a continuous flow of replenishment feed and recycle gas through the reaction zone. A surface gas velocity of 82 cm / s was used to form the fluidized bed. The reactor was operated at a total pressure of 326 psig, and the temperature of the incoming recycle gas was adjusted using a gas cooler to accommodate any change in heat generation due to polymerization to maintain a constant reactor temperature. The fluidized bed was held at a constant height by recovering a portion of the bed at the same rate as the production rate of the individual particulate product, and the product was semi-continuously or continuously recovered into a fixed volume chamber through a series of valves. At the same time, the reactor was evacuated.

Ethylene was used as the reaction and 1-hexene was used as the comonomer. Hydrogen, which is a molecular weight regulator, was adjusted according to polymer properties, and an antistatic agent (Armostat400) was added at 2 kg / h to remove static electricity generated during the process. The impurity remover differs in type and dose depending on the example, and was not added in Example 1. The composition in the first gas phase polymerization reactor was 45 mol% ethylene, 0.67 mol% 1-hexene, 250 ppm hydrogen and the remaining propane. The propane was supplied in a liquid state to the reaction zone at about 1.0 m from the bottom of the reactor by a pump, the feed amount was 5.0 tons / hour, the propane supplied was divided into three, and fed into the reactor at an angle of 120 degrees to each other. It was.

The final polymer was removed from the hydrocarbon component and the oil component with water vapor, dried over dry nitrogen and stored in silos. During the flow polymerization, no polymer lumps were formed, the reaction temperature was controlled to 75 ± 0.5 ° C., and the physical properties of the produced polymer were 1.0g / 10 min of melt index, 0.9145g / cc density, and 0.46 g / cc bulk density. . Catalyst productivity was 6,000 kg / kg-catalyst, run for 14 consecutive days, and no downtime due to polymer mass or fouling. The gas phase polymerization conditions and reaction results are shown in Table 1 overall.

Example 2

Catalytic preparation, slurry continuous prepolymerization, and gas phase polymerization were carried out in the same manner as in Example 1, except that 0.5 kg / h of triisobutylaluminum was used as the impurity removing agent, and was carried out under the conditions shown in Table 1. The polymerization reaction was run continuously for 14 days, and there was no shutdown due to polymer mass or fouling. The gas phase polymerization conditions and reaction results are shown in Table 1 overall.

Comparative Example 1

A. Preparation of Catalyst

The reactor was configured in the same manner as in Example 1. The reactor was maintained at 40 ° C., 114 liters of 10% by weight aluminoxane in toluene was added to the reactor followed by 170 liters of toluene. Also, a 1.859 kg suspension of indenylzirconium dichloride (Ind ₂ ZrCl ₂ ) in 49 liters of toluene was transferred to the reactor. 146 liters of toluene were then added to the reactor containing the suspension, and 40 kg of silica (ES70Y, Ineos) was added to the reactor. After reacting with ultrasonic waves for 1 hour, the mixture was washed 5 times with hexane and dried.

B. Weather Polymerization

Slurry continuous prepolymerization and gas phase polymerization were carried out in the same manner as in Example 1, except that gas propane was injected without injecting liquid propane, and the reaction was performed under the conditions shown in Table 1. As shown.

Comparative Example 2

Preparation of the catalyst was carried out in the same manner as in Comparative Example 1, the slurry continuous prepolymerization and gas phase polymerization in the same manner as in Example 2, except that the gas propane was injected without the injection of liquid propane, and carried out under the conditions shown in Table 1 Was carried out, and the reaction results are shown in Table 1.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 catalyst Invention catalyst Invention catalyst Ind ₂ ZrCl ₂ Ind ₂ ZrCl ₂ MIE (g / 10min) 1.0 1.0 3.0 3.0 Density (g / cc) 0.9145 0.9180 0.9180 0.9180 Catalyst amount (kg / h) 3.0 3.0 3.0 3.0 Prepolymerization Productivity (g / gcat.) 150 150 150 150 Triisobutylaluminum (kg / h) 0 0.5 0 0.5 Circulating gas composition Primary Vapor Reactor Hydrogen (ppm) 250 200 60 60 Ethylene (mol%) 45 40 50 50 Hexene (mol%) 0.67 0.65 0.75 0.75 Reactor temperature (℃) 75 80 80 80 Reactor pressure (atm) 21 21 21 21 Circulating gas flow rate (m / s) 0.82 0.86 0.80 0.80 Liquid Propane Injection (t / h) 5.0 5.0 0 0 Circulating gas composition Secondary Vapor Reactor Hydrogen (ppm) 300 230 150 190 Ethylene (mol%) 50 55 55 60 Hexene (mol%) 0.75 0.77 0.88 0.86 Reactor temperature (℃) 75 80 80 80 Reactor pressure (atm) 19 17.5 18 18 Terminal speed (m / s) 0.6 0.6 0.6 0.6 Circulating gas flow rate (m / s) 0.86 0.82 0.78 0.80 Output (ton / h) 18 17 10.2 8.2 Productivity (g / gcat) 6,000 5,670 3,330 3,100 Particle Bulk Density (g / cc) 0.46 0.44 0.33 0.32 Particle size (microns) 1,820 1,780 1,490 1,460 Driving days 14 14 5 3

In the table, MIE represents Melt Index (MI). From the above examples and comparative examples, it can be seen that the polymerization method of the olefin according to the present invention can not only reduce the occurrence of fouling in the polymerization reactor, but also suppress the generation of fine particles and improve the productivity.

1 is a schematic diagram of a polymerization reactor for polymerizing a polyolefin according to one embodiment of the present invention.

2 is a schematic representation of a fluidized bed gas phase polymerization reactor suitable for the polymerization of polyolefins according to the present invention.

3 is a schematic representation of a liquid direct injection fluidized-bed gas phase polymerization reactor particularly suitable for the polymerization of polyolefins according to the present invention.

4 is a cross-sectional view taken along the line A of the reactor shown in FIG.

Claims (4)

An organometallic compound represented by Formula 1 below; Aluminoxanes; And gas phase polymerizing one or more olefins in the presence of a catalyst for olefin polymerization comprising an organic transition metal compound represented by the following Chemical Formula 2, While passing through the polymerization zone in which the olefin is polymerized, the heat of polymerization is removed and a circulating gas is supplied to maintain an equilibrium state of the polymerization zone, wherein the circulating gas is supplied to the polymerization reactor in a liquid state. Way. [Formula 1] M ¹ R ¹ _l R ² _m R ³ _n or R ² _m R ³ _n M ¹ R ¹ _l -QR ¹ _l M ¹ R ² _m R ³ _n In Formula 1, M ¹ is a 2A, 2B or 3B group element of the periodic table. R ¹ is a substituted or unsubstituted cyclic hydrocarbon group having 5 to 30 carbon atoms having two or more conjugated double bonds, R ² and R ³ are each independently a hydrocarbon group having 1 to 24 carbon atoms, and l is an integer of 1 or more , m and n are each independently an integer of 0 to 2, l + m + n is equal to the valence of M ¹ , Q is (CR ⁵ ₂ ) _b , (SiR ⁵ ₂ ) _b , connecting R ¹ (GeR ⁵ ₂ ) _b is a divalent group selected from _b , NR ⁵ or PR ⁵ , wherein the substituents R ⁵ are each independently a hydrogen atom, an alkyl radical having 1 to 20 carbon atoms, a cycloalkyl radical having 3 to 20 carbon atoms, and a carbon number An alkenyl radical of 1 to 20, an aryl radical of 6 to 20 carbon atoms, an alkylaryl radical of 7 to 20 carbon atoms, or an arylalkyl radical of 7 to 20 carbon atoms, b is 1 to 4, and Q is (CR ⁵ ₂ ) _b , (SiR ⁵ ₂ ) _b , (GeR ⁵ ₂ ) _b , _two carbon atoms connected to carbon (C), silicon (Si), and germanium (Ge) Substituents R ⁵ may be linked to each other to form a ring having 2 to 7 carbon atoms. [Formula 2]

In Formula 2, M ² is titanium (Ti), zirconium (Zr) or hafnium (Hf), R ⁴ is a substituted or unsubstituted cyclic hydrocarbon group having 5 to 30 carbon atoms having two or more conjugated double bonds. , X is a halogen atom, p is an integer of 0 or 1, q is an integer of 3 or 4, p + q is equal to the valence of the metal M ² . The polymerization method of olefin according to claim 1, wherein the circulating gas is uniformly divided into three portions on a plane perpendicular to the traveling path of the circulating gas and introduced into the polymerization reaction region. The method of claim 1, wherein the circulating gas is uniformly divided into three portions on a plane parallel to the ground, and is introduced at three points at an angle of 100 to 140 degrees to merge with each other at the center of the polymerization reactor. The polymerization method of olefin which is supplied. The method of claim 1, wherein the circulating gas is propane, butane, pentane, hexane, octane, decane, dodecane, cyclopentane, methylcyclopentane, cyclohexane, benzene, toluene, xylene, dichloromethane, chloroethane, 1, A method for the polymerization of olefins selected from the group consisting of 2-dichloroethane, chlorobenzene, ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, and mixtures thereof.

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