JP2004043823A - Vapor-phase polymerization method for olefin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vapor-phase polymerization method for an olefin wherein a dry prepolymerization catalyst for olefin polymerization excellent in olefin polymerization activity is used. <P>SOLUTION: In this method, an olefin in a vapor phase is polymerized while a prepolymerization catalyst having a volatile content of 2.0 wt% or lower in the state of a solid powder is being supplied to a polymerization reactor. The prepolymerization catalyst is prepared by the prepolymerization of an olefin on a solid catalyst component which is prepared by causing (A) a particulate carrier comprising an oxide of at least one element selected from elements of the groups 2, 4, 12, 13, and 14 of the periodic table to carry (B) a transition metal compound of the group 4 of the periodic table and (C) an organoaluminumoxy compound. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a method for gas phase polymerization of olefins using a dry prepolymerization catalyst for olefin polymerization having excellent polymerization activity and fluidity.

(4) Olefin polymers represented by polyethylene or linear low-density polyethylene (LLDPE), which is a copolymer of ethylene and α-olefin, are widely used as film forming materials. An olefin polymer has been conventionally produced by (co) polymerizing an olefin in the presence of a titanium-based solid catalyst component containing magnesium, titanium and halogen as essential components. In recent years, as a catalyst capable of (co) polymerizing an olefin with higher polymerization activity, a metallocene catalyst comprising a solid catalyst component containing a metallocene compound of a Group 4 metal of the periodic table such as zirconium and an organoaluminum component has been used. Is being developed.

オ レ フ ィ ン (Co) polymerization of olefins using the above-mentioned catalyst is carried out by a solution polymerization method, a suspension polymerization method or a gas phase polymerization method. In the gas phase polymerization method, a polymer can be obtained in the form of particles, and the liquid phase polymerization method does not require a polymer precipitation step after polymerization, a polymer separation step, and the like. As a result, the manufacturing process can be simplified, and the manufacturing cost can be reduced.

In the gas phase polymerization method, a solid catalyst and an olefin are continuously supplied to a polymerization reactor (fluidized bed reactor), and the olefin is polymerized or copolymerized in a fluidized bed. In this method, the (co) polymerization of the olefin is continuously performed by extracting the olefin. However, when an olefin is polymerized by a gas phase polymerization method, polymer particles adhere to each other in a fluidized bed to form a polymer lump, and the fluidity of the fluidized bed is reduced. In some cases, the polymer adheres to the sheet to form a sheet-like polymer and the fluidity of the fluidized bed is reduced, so that the operation has to be stopped.

Under such circumstances, it has been desired to develop a polymerization method capable of performing gas phase polymerization of olefins stably for a long period of time, and in particular, to stabilize olefins for a long period of time using a metallocene catalyst having excellent polymerization activity. There is a demand for a polymerization method capable of performing gas phase polymerization.

The present inventors have conducted intensive studies on such problems in the gas-phase polymerization method of olefins, and found that hydrocarbons introduced into the polymerization system were supplied to the polymerization reactor in order to supply a solid catalyst as a slurry of a hydrocarbon medium. Was liquefied depending on the temperature, and it was found that one of the causes was that the fluidity of the fluidized bed was reduced. However, if the solid catalyst is supplied to the polymerization reactor without being slurried, it is difficult to supply the solid catalyst to the polymerization reactor stably due to the low fluidity of the solid catalyst, or the flow of the solid catalyst may be difficult. When a fluidity improver was added to improve the polymer properties, the polymerization activity sometimes decreased. Further, when the solid catalyst is dried in order to improve the fluidity of the solid catalyst, the polymerization activity of the solid catalyst may decrease depending on the drying conditions.
The present inventors have further studied based on such knowledge, and as a result, a prepolymerized catalyst dried under specific conditions and having a volatile component amount of not more than a specific amount has excellent polymerization activity and fluidity. The inventors have found that the present invention is excellent, and have completed the present invention.

An object of the present invention is to provide a method for gas phase polymerization of olefins using a dry prepolymerization catalyst for olefin polymerization which has excellent olefin polymerization activity and excellent fluidity.

The olefin gas phase polymerization method according to the present invention,
(A) a particulate carrier comprising an oxide of at least one element selected from Group 2, 4, 12, 13 and 14 of the periodic table;
(B) a transition metal compound of Group 4 of the periodic table;
(C) When the olefin is polymerized in the gas phase while supplying a prepolymerized catalyst in which an olefin is prepolymerized to a solid catalyst component carrying an organoaluminum oxy compound, to the polymerization reactor, the amount of volatile component is 2. It is characterized in that a pre-polymerization catalyst of 0% by weight or less is supplied to a polymerization reactor in a solid powder state.

In the olefin polymerization method according to the present invention, the olefin is polymerized in the gas phase while the dry prepolymerization catalyst for olefin polymerization is supplied to the polymerization reactor in the form of a solid powder. And the olefin can be stably polymerized. Further, since the catalyst is not supplied to the polymerization reactor in the form of slurry, polymerization can be performed even at a temperature equal to or lower than the boiling point of the hydrocarbon used for slurrying the catalyst, and the polymerization temperature range becomes wider than before.

Hereinafter, the gas phase polymerization method of olefin according to the present invention will be specifically described.

In the present specification, the term "polymerization" may be used to mean not only homopolymerization but also copolymerization, and the term "polymer" means not only homopolymer but also copolymer. It is sometimes used in a sense that also includes coalescence.

The dry prepolymerization catalyst for olefin polymerization according to the present invention,
(A) In the fine particle carrier,
(B) a transition metal compound of Group 4 of the periodic table;
(C) A pre-polymerized catalyst in which an olefin is pre-polymerized on a solid catalyst component in which an organoaluminum oxy compound is supported, wherein the solid catalyst has a volatile component amount of 2.0% by weight or less.

First, each component forming the dry prepolymerization catalyst for olefin polymerization according to the present invention will be described. The particulate carrier (A) used in the present invention is a particulate inorganic compound composed of an oxide of at least one element selected from Groups 2, 4, 12, 13, and 14 of the periodic table.

As the particulate inorganic compound, a porous oxide is preferable, and specifically, SiO ₂ , Al ₂ O ₃
, MgO, ZrO ₂ , TiO ₂ , B ₂ O ₃ , CaO, ZnO, BaO, ThO ₂ , or a mixture thereof or a mixture containing these and other oxides, for example, SiO ₂ —MgO, SiO ₂ —Al ₂ Examples include O ₃ , SiO ₂ —TiO ₂ , SiO ₂ —V ₂ O ₅ , SiO ₂ —Cr ₂ O ₃ , and SiO ₂ —TiO ₂ —MgO. Among them, those containing at least one component selected from the group consisting of SiO ₂ , Al ₂ O ₃ and MgO as a main component are preferable, and SiO ₂ is particularly preferable. These can be used in combination of two or more.

The fine particle carrier (A) used in the present invention has a specific surface area in the range of 50 to 1000 m ² / g, a pore volume in the range of 0.3 to 2.5 cm ³ / g, and an average particle size of 0.3 to 2.5 cm ³ / g. It is desirable that the diameter be in the range of 1 to 300 μm.

遷移 As the transition metal compound (B) belonging to Group 4 of the periodic table used in the present invention, a compound containing a ligand having a cyclopentadienyl skeleton represented by the following general formula (I) can be exemplified.

ML _X ... (I)
In the formula, M represents one transition metal atom selected from transition metal atoms of Group 4 of the periodic table, and is preferably zirconium, titanium or hafnium.

X is the valence of the transition metal atom M, and indicates the number of ligands L coordinated to the transition metal atom M.

L represents a ligand or a group which coordinates to the transition metal atom M, and at least one L is a ligand having a cyclopentadienyl skeleton, and a ligand having the cyclopentadienyl skeleton And L represents a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group, or SO ₃ R (where R is the number of carbon atoms which may have a substituent such as halogen). Is a hydrocarbon group of 1 to 8), a halogen atom or a hydrogen atom. Two or more Ls may be the same or different from each other.

Examples of the ligand having a cyclopentadienyl skeleton include a cyclopentadienyl group; a methylcyclopentadienyl group, a dimethylcyclopentadienyl group, a trimethylcyclopentadienyl group, a tetramethylcyclopentadienyl group, Methylcyclopentadienyl group, ethylcyclopentadienyl group, methylethylcyclopentadienyl group, propylcyclopentadienyl group, methylpropylcyclopentadienyl group, butylcyclopentadienyl group, methylbutylcyclopentadienyl Groups, alkyl-substituted cyclopentadienyl groups such as hexylcyclopentadienyl group; indenyl group; alkyl-substituted indenyl group; 4,5,6,7-tetrahydroindenyl group; and fluorenyl group. These groups may be substituted by a halogen atom, a trialkylsilyl group or the like.

ア ル キ ル Among these ligands having a cyclopentadienyl skeleton, an alkyl-substituted cyclopentadienyl group is particularly preferred.

When the compound represented by the general formula (I) contains two or more ligands having a cyclopentadienyl skeleton, two of the ligands having a cyclopentadienyl skeleton are ethylene, propylene A substituted alkylene group such as isopropylidene and diphenylmethylene; a silylene group; a dimethylsilylene group; and a bonding group such as a substituted silylene group such as a diphenylsilylene group and a methylphenylsilylene group.

Specific examples of the ligand other than the ligand having a cyclopentadienyl skeleton include the following.

Examples of the hydrocarbon group having 1 to 12 carbon atoms include an alkyl group, a cycloalkyl group, an aryl group, and an aralkyl group.
Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, and a butyl group.
Examples of the cycloalkyl group include a cyclopentyl group and a cyclohexyl group,
Examples of the aryl group include a phenyl group and a tolyl group.
Examples of the aralkyl group include a benzyl group and a neophyl group.

Examples of the alkoxy group include those having 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group and a butoxy group.

The aryloxy group includes one having 6 to 20 carbon atoms, such as a phenoxy group.

Examples of the trialkylsilyl group include those having a total of 3 to 21 carbon atoms, such as a trimethylsilyl group and a triethylsilyl group.

The ligand represented by SO ₃ R includes a p-toluenesulfonato group, a methanesulfonato group,
Examples thereof include a trifluoromethanesulfonato group.

Examples of the halogen include fluorine, chlorine, bromine and iodine. When the valence of the transition metal atom is 4, for example, the transition metal compound (B) used in the present invention is more specifically represented by the following general formula (I ′).

R ¹ R ² R ³ R ⁴ M ... (I ')
In the formula, M is the same transition metal atom as described above, and R ^{1 to} R ⁴ represent a ligand or a group which coordinates to the transition metal atom M.

R ¹ is a ligand having the same cyclopentadienyl skeleton as L described above.

R ² , R ³ and R ⁴ may be the same or different from each other, and have the same cyclopentadienyl skeleton as L described above, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, One group or atom selected from the group consisting of an aryloxy group, a trialkylsilyl group, SO ₃ R, a halogen atom and a hydrogen atom.

In the present invention, in the general formula (I ′), one of R ² , R ³ and R ⁴ is a transition metal compound having a ligand having a cyclopentadienyl skeleton, for example, R ¹ and R ² are each a cyclopentadiene. Transition metal compounds that are ligands having an enyl skeleton are preferably used. These ligands having a cyclopentadienyl skeleton may be bonded via the above-described bonding group. In this case, R ³ and R ⁴ are an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, a trialkylsilyl group, SO ₃ R, a halogen atom or a hydrogen atom.

Specific examples of the transition metal compound in which M is zirconium among the compounds represented by the general liquid (I) are shown below.

Bis (indenyl) zirconium dichloride,
Bis (indenyl) zirconium dibromide,
Bis (indenyl) zirconium bis (p-toluenesulfonate),
Bis (4,5,6,7-tetrahydroindenyl) zirconium dichloride,
Bis (fluorenyl) zirconium dichloride,
Ethylene bis (indenyl) zirconium dichloride,
Ethylene bis (indenyl) zirconium dibromide,
Ethylene bis (indenyl) dimethyl zirconium,
Ethylene bis (indenyl) diphenyl zirconium,
Ethylenebis (indenyl) methylzirconium monochloride,
Ethylenebis (indenyl) zirconiumbis (methanesulfonate),
Ethylenebis (indenyl) zirconiumbis (p-toluenesulfonate),
Ethylene bis (indenyl) zirconium bis (trifluoromethanesulfonate),
Ethylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride,
Isopropylidene (cyclopentadienyl-fluorenyl) zirconium dichloride,
Isopropylidene (cyclopentadienyl-methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (cyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (methylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (dimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (trimethylcyclopentadienyl) zirconium dichloride,
Dimethylsilylenebis (indenyl) zirconium dichloride,
Dimethylsilylenebis (indenyl) zirconiumbis (trifluoromethanesulfonate),
Dimethylsilylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride,
Dimethylsilylene (cyclopentadienyl-fluorenyl) zirconium dichloride,
Diphenylsilylenebis (indenyl) zirconium dichloride,
Methylphenylsilylenebis (indenyl) zirconium dichloride,
Bis (cyclopentadienyl) zirconium dichloride,
Bis (cyclopentadienyl) zirconium dibromide,
Bis (cyclopentadienyl) methyl zirconium monochloride,
Bis (cyclopentadienyl) ethyl zirconium monochloride,
Bis (cyclopentadienyl) cyclohexylzirconium monochloride,
Bis (cyclopentadienyl) phenyl zirconium monochloride,
Bis (cyclopentadienyl) benzylzirconium monochloride,
Bis (cyclopentadienyl) zirconium monochloride monohydride,
Bis (cyclopentadienyl) methylzirconium monohydride,
Bis (cyclopentadienyl) dimethyl zirconium,
Bis (cyclopentadienyl) diphenyl zirconium,
Bis (cyclopentadienyl) dibenzyl zirconium,
Bis (cyclopentadienyl) zirconium methoxychloride,
Bis (cyclopentadienyl) zirconium ethoxycyclolide,
Bis (cyclopentadienyl) zirconium bis (methanesulfonate),
Bis (cyclopentadienyl) zirconium bis (p-toluenesulfonate),
Bis (cyclopentadienyl) zirconium bis (trifluoromethanesulfonate),
Bis (methylcyclopentadienyl) zirconium dichloride,
Bis (dimethylcyclopentadienyl) zirconium dichloride,
Bis (dimethylcyclopentadienyl) zirconium ethoxycyclolide,
Bis (dimethylcyclopentadienyl) zirconium bis (trifluoromethanesulfonate),
Bis (ethylcyclopentadienyl) zirconium dichloride,
Bis (methylethylcyclopentadienyl) zirconium dichloride,
Bis (propylcyclopentadienyl) zirconium dichloride,
Bis (methylpropylcyclopentadienyl) zirconium dichloride,
Bis (butylcyclopentadienyl) zirconium dichloride,
Bis (methylbutylcyclopentadienyl) zirconium dichloride,
Bis (methylbutylcyclopentadienyl) zirconium bis (methanesulfonate),
Bis (trimethylcyclopentadienyl) zirconium dichloride,
Bis (tetramethylcyclopentadienyl) zirconium dichloride,
Bis (pentamethylcyclopentadienyl) zirconium dichloride,
Bis (hexylcyclopentadienyl) zirconium dichloride,
Bis (trimethylsilylcyclopentadienyl) zirconium dichloride.

In the above examples, compounds having a di-substituted cyclopentadienyl ring are 1,2- and
Including compounds having 1,3-substituted cyclopentadienyl rings, compounds having trisubstituted cyclopentadienyl rings are compounds having 1,2,3- and 1,2,4-substituted cyclopentadienyl rings including. Alkyl groups such as propyl and butyl include isomers such as n-, i-, sec- and tert-.

で は In the present invention, as the transition metal compound (B), a transition metal compound obtained by replacing the zirconium metal with a titanium metal or a hafnium metal in the zirconium compound as described above can also be used.

These transition metal compounds (B) may be used alone or in combination of two or more. It may be used after being diluted with a hydrocarbon or a halogenated hydrocarbon.

In the present invention, as the transition metal compound (B), a zirconocene compound in which the central transition metal atom is zirconium and has a ligand having at least two cyclopentadienyl skeletons is preferably used.

Specific examples of the organoaluminum oxy compound (C) used in the present invention include conventionally known aluminoxanes and benzene-insoluble organoaluminum oxy compounds exemplified in JP-A-2-78687.

A conventionally known aluminoxane can be produced from the organoaluminum compound (D) described below, for example, by the following method.
(1) Compounds containing water of adsorption or salts containing water of crystallization such as hydrated magnesium chloride, hydrated copper sulfate, hydrated aluminum sulfate, hydrated nickel sulfate, hydrated cerous chloride A method of adding an organoaluminum compound such as trialkylaluminum to a hydrocarbon medium suspension of the above, and reacting the organoaluminum compound with adsorbed water or crystal water.
(2) A method in which water, ice or water vapor is allowed to act directly on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether or tetrahydrofuran.
(3) A method of reacting an organoaluminum compound such as trialkylaluminum with an organotin oxide such as dimethyltin oxide or dibutyltin oxide in a medium such as decane, benzene or toluene.

The aluminoxane may contain a small amount of an organometallic component. Alternatively, the solvent or unreacted organoaluminum compound may be removed from the recovered aluminoxane solution by distillation, and then redissolved in a solvent or suspended in a poor solvent for aluminoxane.

The dry prepolymerization catalyst for olefin polymerization according to the present invention can be obtained by using the above-mentioned (A) fine-particle carrier in the presence of a solid catalyst component in which (B) a transition metal compound and (C) an organoaluminum oxy compound are supported. This is a solid catalyst obtained by drying a prepolymerized catalyst obtained by prepolymerizing an olefin.

FIG. 1 shows a process for preparing a dry prepolymerization catalyst for olefin polymerization according to the present invention.

(4) The solid catalyst component can be prepared by bringing the (A) transition metal compound and the (C) organoaluminum oxy compound into contact with the (A) particulate carrier as described above.

The contact of each of the above components can be performed in an inert hydrocarbon medium, and specific examples of such an inert hydrocarbon medium include propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene. Aliphatic hydrocarbons such as cyclopentane, cyclohexane and methylcyclopentane; aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as ethylene chloride, chlorobenzene, dichloromethane and the like. And the like.

In preparing the solid catalyst component, (B) the transition metal compound (in terms of transition metal atom) is usually 0.001 to 1.0 mmol, preferably 0.01 to 0.5 mmol per 1 g of the fine particle carrier (A). The organic aluminum oxy compound (C) is used in an amount of usually 0.1 to 100 mmol, preferably 0.5 to 20 mmol.

固体 The solid catalyst component obtained in this manner may contain other components useful for olefin polymerization such as an electron donor and a reaction aid, if necessary, in addition to the above-mentioned catalyst component.

As a method for prepolymerizing an olefin in the presence of the solid catalyst component, a conventionally known method is used.For example, the method can be performed by introducing an olefin into an inert hydrocarbon medium in the presence of the solid catalyst component. it can. As the inert hydrocarbon medium used for preparing the prepolymerized catalyst, the same as described above can be mentioned.

At the time of prepolymerization, the following organoaluminum compound (D) can be used together with the solid catalyst component.

As the organoaluminum compound used in the present invention as the (D) organoaluminum compound and also used in preparing the aluminoxane as described above, specifically,
Trimethyl aluminum, Triethyl aluminum, Tripropyl aluminum, Triisopropyl aluminum, Tri n-butyl aluminum, Triisobutyl aluminum, Tri sec-butyl aluminum, Tri tert-butyl aluminum, Tripentyl aluminum, Trihexyl aluminum, Trioctyl aluminum, Tridecyl Trialkyl aluminums such as aluminum;
Tricycloalkyl aluminums such as tricyclohexyl aluminum, tricyclooctyl aluminum;
Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, diethylaluminum bromide and diisobutylaluminum chloride;
Dialkyl aluminum hydrides such as diethyl aluminum hydride and diisobutyl aluminum hydride;
Dialkyl aluminum alkoxides such as dimethyl aluminum methoxide and diethyl aluminum ethoxide;
Examples include dialkylaluminum aryloxides such as diethylaluminum phenoxide.

の う ち Among these, trialkylaluminum and tricycloalkylaluminum are preferable, trialkylaluminum is more preferable, and triethylaluminum and triisobutylaluminum are particularly preferable.

Further, isoprenyl aluminum represented by the following general formula can also be used as the organic aluminum compound.
_{(I-C 4 H 9)} x Al y (C 5 H 10) z
(Where x, y, and z are positive numbers and z ≧ 2x).
These may be a combination of two or more.

The organic aluminum compound (D) used as necessary in the present invention may contain a small amount of a metal component other than aluminum.

In the thus prepared prepolymerized catalyst, it is desirable that 0.5 to 300 g, preferably 1 to 200 g, more preferably 2 to 100 g of the prepolymerized olefin polymer is present per 1 g of the solid catalyst component. .

乾燥 The dry prepolymerization catalyst for olefin polymerization according to the present invention can be obtained by drying the above prepolymerization catalyst. The drying of the prepolymerized catalyst is usually performed after removing the hydrocarbon as a dispersion medium from the obtained suspension of the prepolymerized catalyst by filtration or the like.

(4) The drying of the prepolymerized catalyst is performed by maintaining the prepolymerized catalyst at a temperature of 50 ° C. or lower, preferably 20 to 40 ° C. under a flow of an inert gas. It is desirable that the amount of volatile components in the obtained dried prepolymerized catalyst is 2.0% by weight or less, preferably 1.0% by weight or less. The amount of the volatile component of the dry prepolymerization catalyst is preferably as small as possible, and there is no particular lower limit, but practically it is 0.001% by weight. The drying time is usually 3 to 8 hours, depending on the drying temperature.

(4) If the amount of the volatile component of the dried pre-polymerization catalyst exceeds 2.0% by weight, the fluidity of the dried pre-polymerization catalyst may be reduced, and the catalyst may not be stably supplied to the polymerization reactor.

The repose angle of the dried prepolymerized catalyst is 50 ° or less, preferably 5 to 47 °, more preferably 10 to 45 °. When the angle of repose of the dried pre-polymerization catalyst exceeds 50 °, the fluidity of the dried pre-polymerization catalyst is reduced, and it may not be possible to stably supply the catalyst to the polymerization reactor.

Here, the volatile component amount of the dry prepolymerization catalyst is measured by, for example, a weight loss method, a method using gas chromatography, or the like.

In the weight loss method, the weight loss when the dried prepolymerized catalyst is heated at 110 ° C. for 1 hour in an inert gas atmosphere is determined, and is expressed as a percentage of the dry prepolymerized catalyst before heating.

(4) In the method using gas chromatography, volatile components such as hydrocarbons are extracted from the dried prepolymerized catalyst, and a calibration curve is prepared according to an internal standard method, and then calculated as a percentage by weight from the GC area.

When the amount of volatile components of the dry prepolymerized catalyst is about 1% by weight or more, a weight loss method is adopted, and the amount of volatile components of the dry prepolymerized catalyst is about 1% by weight. When the content is not more than% by weight, a method using gas chromatography is employed.

(4) Examples of the inert gas used for drying the prepolymerized catalyst include a nitrogen gas, an argon gas, and a neon gas. Such an inert gas has an oxygen concentration of 20 ppm or less, preferably 10 ppm or less, more preferably 5 ppm or less, and a water content of 20 ppm or less, preferably 10 ppm or less, and more preferably 5 ppm or less. When the oxygen concentration and the water content in the inert gas exceed the above ranges, the olefin polymerization activity of the dry prepolymerization catalyst may be significantly reduced.

An inert gas having an oxygen concentration of 20 ppm or less and a water content of 20 ppm or less is obtained, for example, by contacting a commercially available inert gas with a catalyst containing 20 to 40% by weight of copper, and then contacting with a molecular sieve. It can be obtained by processing.

Examples of the copper-containing catalyst used for treating the inert gas include a hydrogenation catalyst containing 20 to 40% by weight of copper, a deoxygenation catalyst, and the like. More specifically, a copper-chromium-based catalyst ( For example, Cu: 35% by weight, Cr: 31% by weight, Ba: 2% by weight, Mn: 2.5% by weight), a copper-based catalyst in which copper is supported on silica (for example, SiO ₂ : 50 to 65% by weight) , Cu; 16 to 30% by weight).

Such a catalyst is commercially available as R3-11 (manufactured by BASF), G-99B, G-108A, G-108B (manufactured by Nissan-Girdler).

When contacting an inert gas with a catalyst containing 20 to 40% by weight of copper, the temperature is in the range of 0 to 100 ° C, preferably 0 to 50 ° C, and the pressure is 1 to 30 kg / cm ² -G. And preferably in the range of ^{1 to} 10 kg / cm ² -G, and the GHSV is in the range of 100 to 2000 hr ⁻¹ , preferably 200 to 2000 hr ⁻¹ , and more preferably 200 to 400 hr ⁻¹ .

As used herein, "GHSV" means gas space velocity per unit time, and the feed gas volume velocity (m ³ / hr) at the temperature and pressure during the reaction was divided by the reactor volume (m ³ ). And the unit is hr ⁻¹ . The reactor volume at this time is an empty volume not filled with the catalyst.

The molecular sieve used in preparing the inert gas preferably has a bulk density of 0.6 to 0.9 g / cm ³ , and such a molecular sieve includes Zeolum A-3 and Zeolum A-4. (Trade name, manufactured by Tosoh), molecular sieve 3A, and molecular sieve 4A (trade name, manufactured by Nippon Unicar).

When bringing the inert gas into contact with the molecular sieve, the temperature is in the range of 0 to 100 ° C., preferably 0 to 50 ° C., and the pressure is 1 to 30 kg / cm ² -G, preferably 1 to 10 kg / g. in the range of cm ² -G, GHSV is 100~2000hr ^-1, preferably it is desirable 200~2000hr ^-1, more preferably from 200~400hr ^-1.

As described above, the inert gas used for drying the prepolymerized catalyst is a catalyst containing 20 to 40% by weight of copper, a temperature of 0 to 100 ° C., a pressure of 1 to 30 kg / cm ² -G, and a GHSV of 100 to 2000 hr. ^-1 and then using a molecular sieve at a temperature of 0 to 100 ° C., a pressure of 1 to 30 kg / cm ² -G, a GHSV of 100 to 2000 hr ⁻¹ , an oxygen concentration of 20 ppm or less, It is preferable that the content be 20 ppm or less.

乾燥 The dry prepolymerization catalyst for olefin polymerization according to the present invention has excellent fluidity, so that it can be stably supplied to the polymerization reactor. Further, the olefin can be (co) polymerized with excellent polymerization activity.

In the gas-phase polymerization method of olefin according to the present invention, when the olefin is polymerized in the gas phase while continuously supplying the solid catalyst and the olefin to the polymerization reactor (fluidized bed reactor), The dry prepolymerization catalyst is supplied in a solid powder state to the polymerization reactor to perform olefin polymerization. In the polymerization, the above-mentioned (A) organoaluminum compound can be used together with the dry prepolymerization catalyst for olefin polymerization. (D) The organoaluminum compound is generally used in an amount of 1 to 1000 mol, preferably 2 to 300 mol, per 1 mol of the transition metal atom in the transition metal compound (B) contained in the dry prepolymerization catalyst for olefin polymerization. Preferably, it is used.

The polymerization reaction can be performed in any of a batch system, a semi-continuous system, and a continuous system. Further, the polymerization can be performed in two or more stages having different reaction conditions. In the present invention, it is preferable to employ a continuous fluidized bed gas phase polymerization method.

The polymerization temperature in the gas phase polymerization method is usually in the range of 50 to 120 ° C, preferably 60 to 100 ° C. The polymerization pressure is usually normal pressure to 100 kg / cm ^2, a range preferably from normal pressure to 50 kg / cm ^2. The gas linear velocity is in the range of 0.4 to 1.5 m / sec, preferably 0.6 to 1.2 m / sec.

Here, the gas-phase polymerization method of olefin according to the present invention will be described in detail with reference to FIG.

The dry prepolymerization catalyst (solid catalyst) 1 for olefin polymerization as described above is continuously supplied to a fluidized bed reactor 3 in a solid powder state via a line 2, for example.

The solid catalyst 1 is used in an amount of 0.00001 to 1.0 mmol / hr, preferably 0.0001 to 0.1 mmol / hr, as calculated as the transition metal atom in the transition metal compound (A) per liter of polymerization volume. Desirably, it is used in an amount of time.

The gaseous olefin is continuously blown into the fluidized bed reactor 3, for example, in the lower part thereof by a gas blower 7 via a line 6. The olefin is supplied from the olefin supply line 9 to the gas blower 7. The olefin blown into the lower part of the fluidized bed reactor 3 disperses the solid catalyst 1 through a gas dispersion plate 4 such as a perforated plate to form a fluidized bed (reaction system) 5. In the fluidized bed 5, the olefin is (co) polymerized to form a particulate olefin (co) polymer. As described above, the olefin supplied to the reactor 3 also serves as a fluidizing gas that keeps the catalyst particles in the reaction system in a fluidized state. It is also possible to use a gas mixture of an olefin and an inert gas such as nitrogen as fluidizing gas. The produced polymer particles are continuously withdrawn from the fluidized bed reactor 3 via the polymer recovery line 11.

On the other hand, the gaseous unreacted olefin that has passed through the fluidized bed 5 is decelerated in the deceleration zone 3 a provided in the upper part of the fluidized bed reactor 3 and then comes out of the fluidized bed reactor 3. Unreacted olefin emerging from the fluidized bed reactor 3 can be circulated via the circulation line 10 together with fresh olefin from the olefin feed line 9. The unreacted olefin is preferably removed of heat of polymerization by the heat exchanger 8 before being circulated. However, the heat of polymerization can also be used to heat fresh olefin before feeding it to reactor 3. Although the heat exchanger 8 is shown downstream of the blower 7 in FIG. 2, it may be arranged upstream of the blower 7.

重合 As described above, the polymerization method of the present invention can be operated continuously.

分子 The molecular weight of the obtained olefin polymer can be adjusted by adding a molecular weight modifier such as hydrogen to the polymerization system or by changing the polymerization temperature. Hydrogen can be supplied from any location in the gas-phase fluidized bed reactor, for example, from line 10.

Here, as the olefin used in the present invention, an α-olefin having 2 to 18 carbon atoms is preferably exemplified. For example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene , 3-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and the like.

Furthermore, cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a- Monocyclic and polycyclic olefins such as octahydronaphthalene, and aromatic and alicyclic vinyl compounds such as styrene, vinyltoluene and vinylcyclohexane are also included.

In addition, polyenes such as butadiene, isoprene, 1,4-hexadiene, dicyclopentadiene, and 5-ethylidene-2-norbornene can be copolymerized with the olefin.

In the present invention, among these, it is preferable to produce linear low density polyethylene (LLDPE) by copolymerizing ethylene and an α-olefin having 3 to 18 carbon atoms. In the present invention, among the olefin polymers, particularly, a constituent unit derived from ethylene is contained at a ratio of 75 to 98% by weight, preferably 80 to 97% by weight, and is derived from an α-olefin having 3 or more carbon atoms. Particularly preferred is a low-crystalline ethylene / α-olefin copolymer so-called linear low-density polyethylene (LLDPE) containing 3 to 25% by weight, preferably 3 to 20% by weight of a structural unit to be produced. Is done.

[Example]
Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

In this specification, the volatile component amount and the angle of repose were measured as follows.

[Amount of volatile components]
Sample preparation
(1) 0.5 g of a sample is weighed, extracted with 30 ml of acetone while cooling with dry ice acetone, and 0.05 g / 5 ml of an acetone solution of methyl benzoate is added as an internal standard.
(2) 1 ml of 13% ammonia water is added, and then acetone is added to make up to 50 ml.
(3) Filter the sample with a 0.2 μm filter.
Analytical method 1 microliter of a sample after pretreatment is taken, and a hydrocarbon having 6 to 10 carbon atoms is detected as a volatile component by gas chromatography. The content of the volatile component is calculated from the GC area after preparing a calibration curve according to the internal standard method, and is expressed as% by weight.
Measurement condition column; fused silica capillary column DB-WAX (manufactured by J & W, 122-7062)
Column length; 0.25 mmφ × 60 m df = 0.25 μm
Column temperature; 50 ° C → 230 ° C (retention time 2 minutes, temperature rise 15 ° C / min)
Detector; FID
Carrier gas; helium split ratio; 1:65
Split flow rate: 73 ml / min.
[Angle of repose]
The angle of repose was measured by a discharge method using Seishin Enterprise Co., Ltd. Multitester MT-1000 ^™ . That is, the dried prepolymerized catalyst was dropped on the measurement table from the upper funnel, and the angle (angle of repose) of the conical mountain slope of the dried prepolymerized catalyst deposited on the table was measured. At this time, the angle was measured at three or more locations, and the value obtained by arithmetically averaging those values was defined as the angle of repose. The smaller the angle of repose, the better the fluidity of the dried prepolymerized catalyst.

[Preparation of solid catalyst component]
10 kg of silica (SiO ₂ ) dried at 250 ° C. for 10 hours was suspended in 154 liters of toluene, and then cooled to 0 ° C. To this suspension, 50.5 l of a toluene solution of methylaminooxane (Al = 1.52 mol / l) was added dropwise over 1 hour. At this time, the temperature in the system was kept at 0 to 5 ° C. Subsequently, the reaction was carried out at 0 ° C. for 30 minutes, then the temperature was raised to 95 ° C. over 1.5 hours, and the reaction was carried out at that temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by decantation. The solid component thus obtained was washed twice with toluene and then resuspended in 100 liters of toluene to a total volume of 160 liters.

To the obtained suspension, 22.0 liters of a toluene solution of bis (1,3-n-butylmethylcyclopentadienyl) zirconium dichloride (Zr = 25.7 mmol / L) was added at 80 ° C. for 30 minutes. The mixture was added dropwise and reacted at 80 ° C. for 2 hours. Thereafter, the supernatant was removed and washed twice with hexane to obtain a solid catalyst component containing 3.2 mg of zirconium per 1 g of silica.

[Preparation of prepolymerized catalyst]
A 350-liter reactor sufficiently purged with nitrogen was charged with 7.0 kg of the solid catalyst component and hexane to make the total volume 285 liters. After cooling the system to 10 ° C., ethylene was blown into the hexane suspension of the solid catalyst component at a flow rate of 8 Nm ³ / hr for 5 minutes. During this time, the temperature in the system was maintained at 10 to 15 ° C. Thereafter, the supply of ethylene was stopped, and 2.4 mol of triisobutylaluminum and 1.2 kg of 1-hexene were charged. After the inside of the system was closed, the supply of ethylene was restarted at a flow rate of 8 Nm ³ / hr. After 15 minutes, the flow rate of ethylene was reduced to 2 Nm ³ / hr, and the pressure in the system was set to 0.8 kg / cm ² -G. During this time, the temperature in the system rose to 35 ° C. Thereafter, ethylene was supplied at a flow rate of 4 Nm ³ / hr for 3.5 hours while controlling the temperature in the system to 32 to 35 ° C. During this time, the pressure in the system was maintained at 0.7 to 0.8 kg / cm ² -G. Next, the inside of the system was replaced with nitrogen, the supernatant was removed, and the system was washed twice with hexane. In this way, a prepolymerized catalyst in which 3 g of the polymer was prepolymerized per 1 g of the solid catalyst component was obtained. [Η] of this prepolymerized polymer was 2.1 dl / g, and the content of 1-hexene was 4.8% by weight.

Further, the supernatant liquid after the prepolymerization was colorless and transparent, the shape of the prepolymerization catalyst was good, and the bulk density was 0.4 g / cm ³ .

[Drying of pre-polymerization catalyst]
20 kg of the hexane suspension of the prepolymerized catalyst obtained above was charged into a jacketed filter dryer having an internal volume of 130 liters as the amount of the prepolymerized catalyst, and hexane was filtered. Thereafter, the temperature of the jacket was raised to 40 ° C., and the system was dried for 3 hours while passing nitrogen gas (oxygen concentration: 10 ppm, water content: 5 ppm) through the system at 6 Nm ³ / hr. During that time, the temperature in the system rose from 20 ° C to 35 ° C. By this operation, a dry prepolymerized catalyst having a volatile component of 0.1% by weight, a bulk density of 0.40 g / cm ³ and an angle of repose of 38.1 ° was obtained.

[Gas phase polymerization]
Using a continuous fluidized-bed gas-phase polymerization apparatus, ethylene and 1-hexene were copolymerized at a total pressure of 20 kg / cm ² -G, a polymerization temperature of 85 ° C., and a gas linear velocity of 0.7 m / sec. The dry prepolymerized catalyst prepared above was continuously supplied at a rate of 60 g / hr, and ethylene, 1-hexene, hydrogen and nitrogen were continuously supplied to maintain a constant gas composition during the polymerization (gas Composition: 1-hexene / ethylene = 0.025, hydrogen / ethylene = 1.5 × 10 ⁻⁴ , ethylene concentration = 71%).

The yield of the obtained ethylene / 1-hexene copolymer was 80 kg / hr, the density was 0.91 g / cm ³ , the melt flow rate (MFR) was 0.61 g / 10 min, and the bulk density was Was 0.44 g / cm ³ , the average particle size of the polymer particles was 1050 μm, and the proportion of the finely divided polymer having a particle size of 100 μm or less was 0.1% by weight or less.

After continuous polymerization for 10 days, the inner wall of the polymerization apparatus and the dispersion plate were inspected, and no adhered polymer was observed.

A dry prepolymerized catalyst having a volatile component of 0.1% by weight was prepared in the same manner as in Example 1 except that nitrogen gas having an oxygen concentration of 25 ppm was used for drying the prepolymerized catalyst. Copolymerization of ethylene and 1-hexene was carried out in the same manner as in Example 1 except for the above, and as a result, the yield was 56 kg / hr.

As a nitrogen gas for drying the prepolymerized catalyst, a nitrogen gas having an oxygen concentration of 25 ppm was first passed through a reaction tube filled with 25 liters of R3-11 manufactured by BASF at 40 ° C., 1 atm, and a GHSV of 300 hr ^-1. Except that nitrogen gas having an oxygen concentration of 5 ppm and a water content of 3 ppm was passed through an adsorption tube filled with 25 liters of molecular sieve (Zeoram A-3, manufactured by Tosoh Corporation) at 40 ° C., 1 atm, and GHSV of 300 hr ^-1 under conditions of 40 ° C. Was prepared in the same manner as in Example 1 to prepare a dry prepolymerized catalyst, and the copolymerization of ethylene and 1-hexene was performed in the same manner as in Example 1 except that the dried prepolymerized catalyst was used. As a result, the yield was 82 kg. / Hr.

[Drying of pre-polymerization catalyst]
20 kg of a hexane suspension of the prepolymerized catalyst obtained in Example 1 was charged as a prepolymerized catalyst in an amount of 20 kg into a jacketed filter dryer having an internal volume of 130 liters, and hexane was filtered. Thereafter, the temperature of the jacket was raised to 40 ° C., and the system was dried for 3 hours while passing nitrogen gas (oxygen concentration: 10 ppm, water content: 7 ppm) through the system at 6 Nm ³ / hr. During that time, the temperature in the system rose from 20 ° C to 35 ° C. By this operation, a dry prepolymerized catalyst having a volatile component of 0.1% by weight, a bulk density of 0.40 g / cm ³ and an angle of repose of 39.3 ° was obtained.

[Gas phase polymerization]
Ethylene and 1-hexene were polymerized in the same manner as in Example 1 except that the dry prepolymerized catalyst prepared above was used.

The yield of the obtained ethylene / 1-hexene copolymer was 78 kg / hr, the density was 0.91 g / cm ³ , the MFR was 0.65 g / 10 min, and the bulk density was 0.43 g / cm ^3. cm ³ , the average particle size of the polymer particles was 1000 μm, and the proportion of the finely divided polymer having a particle size of 100 μm or less was 0.1% by weight or less.

After continuous polymerization for 10 days, the inner wall of the polymerization apparatus and the dispersion plate were inspected, and no adhered polymer was observed.

[Comparative Example 1]
[Drying of pre-polymerization catalyst]
20 kg of a hexane suspension of the prepolymerized catalyst obtained in Example 1 was charged as a prepolymerized catalyst in an amount of 20 kg into a jacketed filter dryer having an internal volume of 130 liters, and hexane was filtered. Thereafter, the temperature of the jacket was raised to 40 ° C., and the system was dried for 1 hour while passing nitrogen gas (oxygen concentration: 10 ppm, water content: 5 ppm) through the system at 6 Nm ³ / hr. During that time, the temperature in the system rose from 20 ° C to 22 ° C. By this operation, a dry prepolymerized catalyst having a volatile component of 3% by weight, a bulk density of 0.33 g / cm ³ and an angle of repose of 60.5 ° was obtained.

[Gas phase polymerization]
An attempt was made to polymerize ethylene and 1-hexene in the same manner as in Example 1 except that the dry prepolymerized catalyst prepared above was used. However, the flowability of the dry prepolymerized catalyst was poor, and the polymer was continuously fed to the polymerization reactor. Could not supply.

[Preparation of prepolymerized catalyst]
10 kg of silica (SiO ₂ ) dried at 250 ° C. for 10 hours was suspended in 154 liters of toluene, and then cooled to 0 ° C. 44.1 L of a toluene solution of methylaminooxane (Al = 1.52 mol / L) was added dropwise to this suspension over 1 hour. At this time, the temperature in the system was kept at 0 to 5 ° C. Subsequently, the reaction was carried out at 0 ° C. for 30 minutes, then the temperature was raised to 95 ° C. over 1.5 hours, and the reaction was carried out at that temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by decantation. The solid component thus obtained was washed twice with toluene and then resuspended in 100 liters of toluene to a total volume of 160 liters.

62 liters of the resulting suspension was transferred to another reactor and a further 75 liters of toluene were added. Next, 50 g of rac-dimethylsilylenebis {1- (2-methyl-4,5-benzoindenyl)} zirconium dichloride was added, and the mixture was stirred for 20 minutes. Then, 270 liters of hexane and 4.35 mol of triisobutylaluminum were added. . Subsequently, propylene was added at 8 kg / hr. Preliminary polymerization was performed at 20 ° C. for 2 hours while supplying at a speed of 2 ° C. Two hours later, the supply of propylene was stopped, and the reaction was continued for another 30 minutes. Thereafter, the inside of the system was replaced with nitrogen, the supernatant was removed, and the system was washed three times with hexane. In this way, a prepolymerized catalyst in which about 3 g of the polymer was prepolymerized per 1 g of the solid catalyst component was obtained.

[Drying of pre-polymerization catalyst]
The prepolymerized catalyst was dried in the same manner as in Example 1 except that the above prepolymerized catalyst was used. As a result, a dry prepolymerized catalyst having a volatile component of 0.2% by weight, a bulk density of 0.40 g / cm ³ and an angle of repose of 36.0 ° was obtained.

[Comparative Example 2]
[Drying of pre-polymerization catalyst]
The prepolymerized catalyst obtained in Example 5 was dried in the same manner as in Comparative Example 1. As a result, a dry prepolymerized catalyst having a volatile component of 2.8% by weight, a bulk density of 0.34 g / cm ³ and an angle of repose of 58.9 ° was obtained.

FIG. 2 is an explanatory view showing a preparation process of a dry prepolymerization catalyst for olefin polymerization according to the present invention. 1 is a schematic diagram showing an example of a gas-phase fluidized-bed reactor capable of polymerizing an olefin according to the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Solid catalyst 3 ... Fluid bed reactor 3a ... Deceleration zone 4 ... Gas dispersion plate 5 ... Fluid bed 7 ... Blower 8 ... Heat exchanger 9 ... Olefin supply line 10 ... Circulation line 11 ... Polymer recovery line

Claims (1)

(A) a particulate carrier comprising an oxide of at least one element selected from Group 2, 4, 12, 13 and 14 of the periodic table;
(B) a transition metal compound of Group 4 of the periodic table;
(C) When the olefin is polymerized in the gas phase while supplying a prepolymerized catalyst in which an olefin is prepolymerized to a solid catalyst component carrying an organoaluminum oxy compound, to the polymerization reactor, the amount of volatile component is 2. A gas phase polymerization method for olefins, comprising supplying a prepolymerization catalyst of 0% by weight or less to a polymerization reactor in a solid powder state.

Images