JP2010006988A - Process for polymerization of olefin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an olefin polymerization process wherein the clogging of a system to supply a catalyst slurry to a polymerization reactor is prevented and thus the reactor can be continuously operated. <P>SOLUTION: The olefin polymerization process comprises the use of 0.3-3.0 mg of an organoaluminum compound together for 1 g of a prepolymerization catalyst, in supplying a catalyst slurry containing the prepolymerization catalyst supported on a solid carrier to a vapor-phase reactor to perform the main polymerization of an olefin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an olefin polymerization method, and more particularly to an olefin polymerization method that prevents clogging of a catalyst slurry supply system to a polymerization reactor and enables continuous operation.

  Films formed from polyolefins such as linear low density polyethylene (LLDPE) are excellent in heat sealability, flexible and tough, excellent in water resistance, moisture resistance, chemical resistance, and inexpensive. It has excellent characteristics and has been widely used.

  Such polyolefins are conventionally produced using a Ziegler-Natta-based solid catalyst and generally by a polymerization method such as a gas phase polymerization method, a suspension polymerization or a solution polymerization method. For example, LLDPE is It is produced by copolymerizing ethylene and an α-olefin having 4 or more carbon atoms using an olefin catalyst. In recent years, in order to improve the performance of polyolefin, as a catalyst having a narrow composition distribution of the obtained polyolefin and having excellent copolymerizability, a group having a cyclopentadienyl skeleton, an indenyl skeleton, a fluorenyl skeleton, etc. is used as a ligand. Metallocene-based catalysts using a group IVB metal compound of the periodic table such as zirconium as a catalyst component have been developed. In particular, in the gas phase polymerization method and suspension polymerization method in which the obtained polymer is required to have good particle properties, a soluble metallocene catalyst is supported on a solid support, and then a prepolymerized catalyst is used. Phase polymerization is drawing attention.

  A prepolymerized catalyst supported on a solid support is made into a slurry, and the catalyst slurry is supplied to the polymerization reactor through a supply system equipped with devices such as a pump and a reverse valve. However, if the polymerization reaction as described above is continued for a long time, a prepolymerized catalyst adheres to a part of the catalyst supply system, for example, a wall of a pump, a reverse valve, or a catalyst storage container, and the supply system is blocked. was there. When the catalyst supply system is blocked, it is impossible to continue the polymerization reactor for a long time. Therefore, it is necessary to stop the operation at regular intervals and clean the catalyst supply system.

  In the case of a gas phase polymerization method, when a olefin is gas phase polymerized in the presence of the metallocene solid catalyst as described above using a fluidized bed reactor, a polymer lump, a sheet or the like is generated in the polymerization vessel. (Also called fouling), and in the suspension polymerization method, a polymer may adhere to a stirring blade or the like, and it may be impossible to perform continuous operation stably for a long time.

As a method for suppressing the above-mentioned problems, particularly fouling, Patent Document 1 (Japanese Patent Laid-Open No. 2002-284808) discloses a method of washing a prepolymerized metallocene-supported solid catalyst with an organic solvent containing organoaluminum. Yes.
JP 2002-284808 A

  However, in the method of Patent Document 1, since the cleaning process is added, the number of processes increases. Moreover, since an organic aluminum-containing organic solvent is used for washing, a large amount of solvent is required, and a large amount of waste liquid is generated. Furthermore, it can be said to be a method with many problems from the viewpoint of industrial production, for example, it takes a long time for the washing process and the drying process. In Patent Document 1, the problem of clogging of the catalyst supply system is not particularly recognized, and the solid catalyst washed with the organoaluminum compound is dried and then slurried and supplied to the polymerization reactor. In this method, it is considered that clogging of the catalyst supply system is not sufficiently suppressed.

  The present invention has been made in view of the prior art as described above, and an object of the present invention is to provide an olefin polymerization method that prevents clogging of a catalyst slurry supply system to a polymerization reactor and enables continuous operation. It is said.

  The gist of the present invention aimed at solving such problems is as follows.

(1) When supplying a catalyst slurry containing a prepolymerized catalyst supported on a solid to a gas phase reactor that performs olefin main polymerization,
An olefin polymerization method characterized by allowing 0.3 to 3.0 mg of an organoaluminum compound to accompany 1 g of the prepolymerized catalyst.

(2) The polymerization method according to (1), wherein the olefin contains ethylene and / or propylene.

(3) The polymerization method according to (1) or (2), wherein an organoaluminum compound is entrained immediately before supplying the catalyst slurry to the gas phase reactor.

(4) The polymerization method according to any one of (1) to (3), wherein the catalyst slurry is immediately supplied to the gas phase reactor after the organoaluminum compound is entrained in the catalyst slurry.

  In the present invention, when the catalyst slurry is supplied to the polymerization reactor, the catalyst slurry supply system is prevented from being blocked by entraining a specific amount of the organoaluminum compound, and the polymerization reactor can be operated continuously.

  Hereinafter, preferred embodiments of the present invention will be described more specifically, including the best mode.

  As shown in the schematic flow chart of the present invention in FIG. 1, in the olefin polymerization method of the present invention, a catalyst slurry containing a prepolymerization catalyst in which a transition metal compound, particularly a metallocene compound is supported in a solid state, is subjected to the main polymerization of olefin. It is characterized in that an organoaluminum compound is accompanied when supplying to the phase reactor. Polymerization using a catalyst slurry entrained with an organoaluminum compound includes polymerization methods such as gas phase polymerization, suspension polymerization, solution polymerization, and bulk polymerization in which the catalyst is supplied to the polymerization vessel in a slurry state. Further, in the gas phase polymerization, the dispersion medium of the catalyst slurry can be flushed, and the catalyst can be supplied to the gas phase polymerization vessel for polymerization.

(Solid supported prepolymerization catalyst)
In the present invention, known catalysts can be widely used as catalysts for olefin polymerization, such as Ziegler-type titanium catalysts and Philip-type chromium oxide catalysts, and among these catalysts, solid supported metallocene catalysts are particularly preferred. It is desirable to use it.

  Examples of the metallocene catalyst include [A] a metallocene compound of a transition metal selected from Group IVB of the periodic table, and [B] (B-1) an organoaluminum oxy compound, (B-2) an organoaluminum compound, and ( B-3) A metallocene catalyst containing at least one compound selected from compounds that react with the metallocene compound [A] to form an ion pair is preferably used.

  The metallocene compound [A] is specifically represented by the following formula (i).

ML _x (i)
Wherein M is a transition metal selected from Zr, Ti, Hf, V, Nb, Ta and Cr, L is a ligand coordinated to the transition metal, and at least one L is cyclopentadi L is a ligand having an enyl skeleton, and L other than the ligand having a cyclopentadienyl skeleton is a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group Group or SO ₃ R group (where R is a hydrocarbon group having 1 to 8 carbon atoms which may have a substituent such as halogen), and x is the valence of the transition metal.)
Examples of the ligand having a cyclopentadienyl skeleton include, for example, a cyclopentadienyl group, a methylcyclopentadienyl group, a dimethylcyclopentadienyl group, a trimethylcyclopentadienyl group, a tetramethylcyclopentadienyl group, Pentamethylcyclopentadienyl, ethylcyclopentadienyl, methylethylcyclopentadienyl, propylcyclopentadienyl, methylpropylcyclopentadienyl, butylcyclopentadienyl, methylbutylcyclopentadi Examples include an alkyl-substituted cyclopentadienyl group such as an enyl group and a hexylcyclopentadienyl group or an indenyl group, a 4,5,6,7-tetrahydroindenyl group, a fluorenyl group, and an alkyl-substituted fluorenyl group. These groups may be substituted with a halogen atom, a trialkylsilyl group or the like.

Of these, an alkyl-substituted cyclopentadienyl group is particularly preferable. Specific examples of the ligand other than the ligand having a cyclopentadienyl skeleton include halogen, fluorine, chlorine, bromine, iodine and the like, and the hydrocarbon group having 1 to 12 carbon atoms is a methyl group. Alkyl groups such as ethyl group, propyl group, isopropyl group and butyl group, cycloalkyl groups such as cyclopentyl group and cyclohexyl group, aryl groups such as phenyl group and tolyl group, aralkyl groups such as benzyl group and neophyll group, etc. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a butoxy group. Examples of the aryloxy group include a phenoxy group. Examples of the SO ₃ R group include a p-toluenesulfonate group and a methanesulfonate group. And a trifluoromethanesulfonate group.

  When the compound represented by the above general formula contains two or more groups having a cyclopentadienyl skeleton, the two groups having a cyclopentadienyl skeleton are alkylene groups such as ethylene and propylene, isopropyl It may be bonded via a substituted alkylene group such as lidene or diphenylmethylene, a silylene group or a dimethylsilylene group, a substituted silylene group such as a diphenylsilylene group or a methylphenylsilylene group. Two or more metallocene compounds [A] can be used in combination.

  The (B-1) organoaluminum oxy compound may be a conventionally known benzene-soluble aluminoxane, or a benzene-insoluble organoaluminum oxy compound as disclosed in JP-A-2-27687. Also good.

  The organoaluminum compound (B-2) is represented by, for example, the following general formula (ii) or (iii).

R ¹ _n AlX _3-n (ii)
(In the formula (ii), R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, X is a halogen atom or a hydrogen atom, and n is 1 to 3).
In the general formula (ii), R ¹ is a hydrocarbon group having 1 to 12 carbon atoms, such as an alkyl group, a cycloalkyl group or an aryl group, and specifically, a methyl group, an ethyl group, or an n-propyl group. Isopropyl group, isobutyl group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, tolyl group and the like.

R ¹ _n AlY _3-n (iii) (R ¹ is the same as (ii) above, Y is —OR ² group, —OSiR ³ ₃ group, —OAlR ⁴ ₂ group, —NR ⁵ ₂ group, — SiR ⁶ ₃ group or —N (R ⁷ ) AlR ⁸ ₂ group, n is 1 to 2, and R ² , R ³ , R ⁴ and R ⁸ are methyl group, ethyl group, isopropyl group, isobutyl group, A cyclohexyl group, a phenyl group, etc., R ⁵ is a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a trimethylsilyl group, etc., and R ⁶ and R ⁷ are a methyl group, an ethyl group, etc.)
Examples of the compound (B-3) that reacts with the metallocene compound [A] to form an ion pair include JP-A-1-501950, JP-A-1-503636, JP-A-3-179005, and JP-A-3. And Lewis acids, ionic compounds, and carborane compounds described in JP-A No. 179006, JP-A-3-207703, JP-A-3-207704, EP-A-0468651, and the like.

Lewis acids include triphenylboron, tris (4-fluorophenyl) boron, tris (p-tolyl) boron, tris (o-tolyl) boron, tris (3,5-dimethylphenyl) boron, tris (pentafluorophenyl) ) boron, and the like _{MgCl 2, Al 2 O 3,} SiO 2 -Al 2 O 3.

  Examples of ionic compounds include triphenylcarbenium tetrakis (pentafluorophenyl) borate, tri-n-butylammonium tetrakis (pentafluorophenyl) borate, N, N-dimethylanilinium tetrakis (pentafluorophenyl) borate, ferrocenium tetra And (pentafluorophenyl) borate.

  The carborane compounds include dodecaborane, 1-carbaundecaborane, bis n-butylammonium (1-carbedodeca) borate, tri-n-butylammonium (7,8-dicarboundaca) borate, tri-n-butylammonium (trideca Hydride-7-carboundeca) borate and the like.

  In the present invention, as the cocatalyst component [B], at least one compound selected from the above components (B-1), (B-2) and (B-3) is used, and these are appropriately combined. They can also be used together. Among these, it is desirable to use at least (B-2) or (B-3) as the cocatalyst component [B].

The metallocene compound [A] and / or the cocatalyst component [B] as described above is used after being brought into contact with the particulate carrier compound to form a solid catalyst. As the carrier compound, a granular or particulate solid having a particle size of 2 to 300 μm, preferably 3 to 200 μm is used. The specific surface area of this support is usually 50 to 1000 m ² / g, and the pore volume is preferably 0.3 to 2.5 cm ³ / g.

Such carriers include porous inorganic oxides are preferably used, 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, such as SiO ₂ —MgO, SiO ₂ —Al ₂ O ₃ , SiO ₂ —TiO ₂ , SiO ₂ —V ₂ O ₅ , SiO ₂ —Cr ₂ O ₃ , SiO ₂ —TiO ₂ —MgO, etc. Is used. Among these, those containing SiO ₂ and / or Al ₂ O ₃ as main components are preferable.

The inorganic oxide includes a small amount of Na ₂ CO ₃ , K ₂ CO ₃ , CaCO ₃ , MgCO ₃ , Na ₂ SO ₄ , Al ₂ (SO ₄ ) ₃ , BaSO ₄ , KNO ₃ , Mg (NO ₃ ) ₂ , Carbonate, sulfate, nitrate and oxide components such as Al (NO ₃ ) ₃ , Na ₂ O, K ₂ O, Li ₂ O may be contained.

  An organic compound can also be used as the carrier. For example, (co) heavy produced mainly from an α-olefin having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene, 4-methyl-1-pentene. A polymer, or a copolymer or copolymer produced mainly from vinylcyclohexane or styrene can be used.

  The contact between the carrier and each of the above components is usually carried out at a temperature of -50 to 150 ° C, preferably -20 to 120 ° C for 1 minute to 50 hours, preferably 10 minutes to 25 hours. This contact can also be carried out in an inert hydrocarbon solvent.

In the solid catalyst prepared as described above, the metallocene compound [A] is 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ gram atom, preferably 10 ⁻⁵ to 2 × 10 ⁻ as a transition metal atom, per 1 g of the support. ^In an amount of ⁴ gram atoms, component [B] is an amount of 10 ^{−3 to} 5 × 10 ⁻² gram atoms, preferably 2 × 10 ⁻³ to 2 × 10 ⁻² gram atoms, per gram of support as aluminum or boron atoms. It is desirable that the

  In the present invention, the olefin is prepolymerized on the solid catalyst as described above to form a prepolymerized catalyst.

  As a method for preparing a prepolymerization catalyst, there is a method in which a small amount of olefin is prepolymerized in an inert hydrocarbon solvent to the solid catalyst. Specific examples of the inert hydrocarbon medium include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane. Aromatic hydrocarbons such as benzene, toluene and xylene; halogenated hydrocarbons such as ethylene dichloride, chlorobenzene and dichloromethane, or mixtures thereof.

  The olefin used in the prepolymerization is 100 to 0 mol% of ethylene, 0 to 49 mol% of propylene, and 0 to 100 mol% of olefin having 4 or more carbon atoms, preferably 100 to 0 mol% of ethylene. , 0 to 20 mol% of propylene and 0 to 100 mol% of an olefin having 4 or more carbon atoms, more preferably 100 to 20 mol% of ethylene, 0 to 20 mol% of propylene and 4 carbon atoms. It is desirable that the above olefin is contained in the range of 0 to 80 mol%, particularly preferably 100 to 20 mol% of ethylene and the olefin having 4 or more carbon atoms in the range of 0 to 80 mol%.

  Specific examples of the olefin having 4 or more carbon atoms include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, Examples include α-olefins having 4 to 20 carbon atoms, such as 1-hexadecene, 1-octadecene, 1-eicosene. Further, cyclopentene, cycloheptene, norbornene, 5-methyl-2-norbornene, tetracyclododecene, 2-methyl 1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a- Octahydronaphthalene, styrene, vinylcyclohexane, dienes and the like can also be used.

  In preparing the prepolymerization catalyst, the metallocene compound [A] is usually used in an amount of 0.001 to 1.0 mmol, preferably 0.005 to 0.5 mmol, in terms of transition metal atoms, per 1 g of the particulate carrier. It is done. In the prepolymerization, the cocatalyst component [B] may be further added. In this case, the cocatalyst component [B] is usually 0.1 to 100 mmol, preferably 0.5 to 20 mmol. Used.

  In the prepolymerized catalyst obtained as described above, the olefin polymer is supported in an amount of about 0.1 to 500 g, preferably 0.3 to 300 g, particularly preferably 1 to 100 g, per 1 g of the particulate carrier. It is desirable that

(Organic aluminum compound)
In the present invention, an organoaluminum compound is entrained when the catalyst slurry containing the above-described prepolymerized catalyst supported on a solid is supplied to a reactor that performs olefin main polymerization.

  As the organoaluminum compound, for example, an organoaluminum compound represented by the following general formula (iv) can be exemplified.

^{_{R a n AlX 3-n ...}} (iv)
(In the formula, Ra represents ^a hydrocarbon group having 1 to 12 carbon atoms, X represents a halogen atom or a hydrogen atom, and n is 1 to 3).
In the general formula (iv), R ^a is a hydrocarbon group having 1 to 12 carbon atoms, such as an alkyl group, a cycloalkyl group, or an aryl group. Specifically, a methyl group, an ethyl group, n- Examples thereof include propyl group, isopropyl group, isobutyl group, pentyl group, hexyl group, octyl group, cyclopentyl group, cyclohexyl group, phenyl group, and tolyl group.

  Specific examples of such organoaluminum compounds include the following compounds. Trialkylaluminum such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, tri-2-ethylhexylaluminum; alkenylaluminum such as isoprenylaluminum; dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutyl Dialkylaluminum halides such as aluminum chloride and dimethylaluminum bromide; alkylaluminum sesquichlorides such as methylaluminum sesquichloride, ethylaluminum sesquichloride, isopropylaluminum sesquichloride, butylaluminum sesquichloride and ethylaluminum sesquibromide; Aluminum dichloride, ethyl aluminum dichloride, isopropyl aluminum dichloride, alkyl aluminum dihalides such as ethyl aluminum dibromide; diethylaluminum hydride, and alkyl aluminum hydride such as diisobutyl aluminum hydride.

  Moreover, the compound represented by the following general formula (v) can also be used as the organoaluminum compound.

^{_{R a n AlY 3-n ...}} (v)
(Wherein, R ^a is the same as above, Y is —OR ^b group, —OSiR ^c ₃ group, —OAlR ^d ₂ group, —NR ^e ₂ group, —SiR ^f ₃ group or —N (R ^g )) AlR ^h ₂ group, n is 0 to 2, and R ^b , R ^c , R ^d and R ^h are methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, cyclohexyl group, phenyl group ^Re is a hydrogen atom, a methyl group, an ethyl group, an isopropyl group, a phenyl group, a trimethylsilyl group, etc., and ^Rf and ^Rg are a methyl group, an ethyl group, etc.)
Specific examples of such an organoaluminum compound include the following compounds.

(1) A compound represented by Al (OR ^b ) ₃ , such as trimethoxyaluminum, triethoxyaluminum, tripropoxyaluminum, tributoxyaluminum, etc.
_{^{(2) R a n Al (}} OR b) a compound represented by _3-n, e.g., dimethylaluminum methoxide, diethylaluminum ethoxide and diisobutylaluminum methoxide,
_{^{(3) R a n Al (}} OSiR c 3) a compound represented by _3-n, e.g., _{Et 2 Al (OSiMe 3),} (iso-Bu) 2 Al (OSiMe 3), (iso-Bu) 2 Al ( OSiEt ₃ ) etc .;
_{^{(4) R a n Al (}} OAlR d 2) a compound represented by _3-n, e.g., Et ₂ AlOAlEt _2, such as _{(iso-Bu) 2 AlOAl (} iso-Bu) 2;
_{^{(5) R a n Al (}} NR e 2) a compound represented by _3-n, e.g., _{Me 2 AlNEt 2, Et 2 AlNHMe} , Me 2 AlNHEt, Et 2 AlN (SiMe 3) 2, (iso-Bu) 2 AlN (SiMe ₃ ) ₂ etc .;
_{^{(6) R a n Al (}} SiR f 3) a compound represented by _3-n, such as _{(iso-Bu) 2 AlSiMe 3} ;
_{^{(7) R a n Al (}} N (R g) AlR h 2) 3-n compound represented by, for example, _{Et 2 AlN (Me) AlEt 2} , (iso-Bu) 2 AlN (Et) Al (iso- Bu) ₂ etc.

  Among the organoaluminum compounds represented by the general formula (iv) or (v), triethylaluminum, triisopropylaluminum, triisobutylaluminum, diethylaluminum chloride, triethoxyaluminum, diethylaluminum ethoxide and the like are particularly preferably used.

(Catalyst slurry)
The catalyst slurry supplied to the polymerization reactor is 0.3 to 3.0 mg, preferably 0.3 to 2.8 mg, more preferably 0.5 to 2.6 mg of the above-mentioned prepolymerized catalyst 1 g. It is prepared by adding an organoaluminum compound. When the addition amount of the organoaluminum compound is less than the above range, the effect of addition of the organoaluminum compound is not achieved and the catalyst slurry supply system to the polymerization reactor is blocked.

  The method for preparing the catalyst slurry is not particularly limited, and for example, a method in which an organoaluminum compound is charged into an inert hydrocarbon medium and then the prepolymerized catalyst supported on the carrier is charged and stirred is preferable.

  Specific examples of the inert hydrocarbon medium include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane. Aromatic hydrocarbons such as benzene, toluene and xylene; halogen atomized hydrocarbons such as ethylene dichloride, chlorobenzene and dichloromethane; and various mineral oils, greases and mixtures thereof.

  The concentration of the resulting catalyst slurry is not particularly limited, but the concentration of the prepolymerized catalyst is preferably 1 to 70 g / liter, more preferably 5 to 50 g / liter, and particularly preferably about 10 to 50 g / liter.

  In addition, the catalyst slurry may contain an organoaluminum oxy compound or an organoaluminum compound as a cocatalyst component [B] used at the time of preparing the prepolymerized catalyst. included. In the catalyst slurry, the total aluminum compound concentration derived from these organoaluminum oxy compounds and organoaluminum compounds is preferably 1 to 160 mmol / liter, more preferably 5 to 110 mmol / liter, and particularly preferably 10 in terms of aluminum atoms. It is about ~ 110 mm / liter.

  Such a catalyst slurry is preferably prepared immediately before being introduced into the catalyst supply system from a device such as a pump or a reversely supported valve. That is, after the slurry is adjusted, it is immediately introduced into the catalyst supply system without passing through the drying step. When the catalyst slurry is supplied to the gas phase polymerization reactor, the specific amount of the organoaluminum compound is accompanied, whereby adhesion of the prepolymerized catalyst to the apparatus in the catalyst supply system is reduced. As a result, the clogging of the catalyst slurry supply system is prevented, and the polymerization reactor can be continuously operated.

  The catalyst slurry is introduced into the reactor by a feeding method conventionally employed in the polymerization reactor.

(Olefin polymerization)
Polymerization is started by introducing the above catalyst slurry and olefin into the polymerization reactor. As the reactor, a reactor conventionally used for polymerization is used without particular limitation. It is desirable to replace the inside of the reactor with an inert gas such as nitrogen before starting the polymerization.

  Specific examples of the olefin in the main polymerization include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, etc. -Olefin and C2-C18 cycloolefin can be used. These may be homopolymerized or copolymerized. In particular, since the polymerization method of the present invention is capable of continuous operation, it is versatile and preferable for the production of highly demanded ethylene homopolymers and ethylene copolymers, or propylene homopolymers and propylene copolymers. Can be adopted.

  If necessary, other polymerizable monomers may be copolymerized with the olefin, for example, vinyl monomers such as styrene, vinyl chloride, vinyl acetate, vinyl acrylate, methyl methacrylate, tetrafluoroethylene, vinyl ether, acrylonitrile and the like. Conjugated dienes such as butadiene and isoprene, non-conjugated polyenes such as 1,4-hexadiene, dicyclopentadiene and 5-vinyl-2-norbornene, acetylenes such as acetylene and methylacetylene, and aldehydes such as formaldehyde It can also be copolymerized.

  The polymerization conditions vary depending on the type of olefin and the copolymerization ratio, etc., but the polymerization pressure is usually within the range of normal pressure to 10 MPa, preferably normal pressure to 5 MPa, and the polymerization temperature is usually 50 to 120 ° C., preferably Is performed within a range of 60 to 100 ° C. In the present invention, the prepolymerization catalyst is used in an amount of usually 0.0001 to 1.0 mmol / hour, preferably 0.0001 to 0.1 mmol / hour in terms of transition metal atoms per liter of polymerization volume. It is desirable that Such olefin polymerization may be carried out in any of batch, continuous, and semi-continuous systems. In the present invention, the polyolefin can be obtained as granular particles by the polymerization as described above. The average particle size of the particles is desirably about 250 to 3000 μm, preferably about 400 to 1500 μm in the gas phase polymerization method, and about 50 to 500 μm, preferably about 70 to 400 μm in the suspension polymerization method. desirable. The polymerization can also be performed in two or more stages having different reaction conditions.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1
[Preparation of solid support]
After 8.5 kg of silica dried at 200 ° C. for 3 hours was suspended in 33 liters of toluene, 82.7 liters of methylaluminoxane solution (Al = 1.42 mol / liter) was added dropwise over 30 minutes. Next, the temperature was raised to 115 ° 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 a decantation method. The obtained solid catalyst component was washed with toluene three times and then resuspended with toluene to obtain a solid support (total volume 150 liters).

[Preparation of solid supported catalyst]
In a reactor sufficiently purged with nitrogen, 19.60 mol of the solid support synthesized above was added in terms of aluminum, and diphenylmethylene (cyclopentadienyl) was stirred at room temperature (20-25 ° C) while stirring the suspension. ) (2,7-di-t-butylfluorenyl) zirconium dichloride (37.38 mmol / liter solution) was added in 2 liters (74.76 mmol), followed by stirring for 60 minutes. After stopping the stirring, the supernatant liquid is removed by decantation, washing is performed twice with 40 liters of n-hexane, and the resulting supported catalyst is reslurried in n-hexane to form a 25 liter catalyst suspension as a solid support. A catalyst was obtained.

[Preparation of solid prepolymerization catalyst by prepolymerization of solid supported catalyst]
Into a reactor equipped with a stirrer, 15.8 liters of purified n-hexane and the above solid-supported catalyst are put in a nitrogen atmosphere, and then 5 mol of triisobutylaluminum is added to produce 3 g of polyethylene in 4 hours per 1 g of the solid component while stirring. Prepolymerization was carried out with an amount of ethylene. The polymerization temperature was kept at 20-25 ° C. After completion of the polymerization, the stirring was stopped, the supernatant was removed by decantation, washing was performed 4 times with 35 liters of n-hexane, and the obtained supported catalyst was made into a catalyst suspension with 20 liters of n-hexane. A solid prepolymerized catalyst (1) was obtained.

[Preparation of catalyst slurry]
Under a nitrogen atmosphere and normal pressure, 24 m ³ of hexane solvent was poured into a SUS container equipped with a stirrer, and the stirrer was cooled to −5 ° C. to −2 ° C. while stirring at 53 rpm. Prior to charging the solid prepolymerized catalyst (1), triisobutylaluminum as an organoaluminum compound was charged at 1600 ppm (1.6 mg with respect to 1 g of the prepolymerized catalyst) per weight of the prepolymerized catalyst. Thereafter, the solid prepolymerized catalyst (1) was added so that the catalyst concentration was 30 g-cat / liter-solvent to prepare a catalyst slurry.

[Catalyst slurry supply]
The obtained catalyst slurry was pressurized to 0.7 MPaG at an output of 600 liters / hour using a diaphragm pump and supplied into the polymerization reactor. The stability of the catalyst supply was evaluated using a Coriolis flow meter (MICROMOTION), measuring glass and pressure.

  Under the above conditions, the catalyst slurry was confirmed to be stably supplied in a continuous operation for 7 days.

(Comparative Example 1)
In Example 1, except that triisobutylaluminum was not used when preparing the catalyst slurry, a catalyst slurry was prepared in the same manner, and the supply stability was evaluated.

  Under these conditions, the supply of catalyst slurry became unstable and the polymerization reaction became unstable in about 8 hours. When the catalyst supply device was opened and inspected, the solid prepolymerized catalyst was charged and adhered to the reverse support valve of the diaphragm pump, the wall surface of the catalyst slurry storage container, the shaft of the stirring device, and the like.

(Comparative Example 2)
In Example 1, a catalyst slurry was prepared in the same manner except that the amount of triisobutylaluminum used in preparing the catalyst slurry was changed to 1000 ppm per weight of the prepolymerized catalyst (0.1 mg based on 1 g of the prepolymerized catalyst) The supply stability was evaluated.

  Under these conditions, the supply of catalyst slurry became unstable and the polymerization reaction became unstable in about 24 hours. When the catalyst supply device was opened and inspected, the solid prepolymerized catalyst was charged and adhered as in Comparative Example 1.

(Example 2)
[Preparation of solid support]
10 kg of silica dried at 250 ° C. for 10 hours was suspended in 154 liters of toluene, and then cooled to 0 ° C. Thereafter, 50.5 liters of a toluene solution of methylaminoxan (Al = 1.52 mol / liter) was added dropwise to the suspension over 1 hour. At this time, the temperature in the system was kept in the range of 0 to 5 ° C. Subsequently, the mixture was reacted at 0 ° C. for 30 minutes, then heated to 95 ° C. over 1.5 hours, and reacted at that temperature for 4 hours. Thereafter, the temperature was lowered to 60 ° C., and the supernatant was removed by a decantation method. The solid component thus obtained was washed twice with toluene and then resuspended in 100 liters of toluene to make a total volume of 160 liters to obtain a solid support.

[Preparation of solid supported catalyst]
To the suspension thus obtained, 22.0 liters of a toluene solution of bis (1,3-n-butylmethylcyclopentadienyl) zirconium dichloride (Zr = 25.7 mmol / liter) was added at 80 ° C. The solution was added dropwise over 30 minutes and further 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 the solid support.

[Preparation of solid prepolymerization catalyst by prepolymerization of solid supported catalyst]
A 350 liter reactor sufficiently purged with nitrogen was charged with 7.0 kg of the solid catalyst component prepared above and hexane to make the total volume 285 liters. After cooling the system to 10 ° C., ethylene was blown into hexane at a flow rate of 8 Nm ³ / h for 5 minutes. During this time, the temperature in the system was maintained at 10 to 15 ° C. Thereafter, the ethylene supply 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, ethylene supply was started again at a flow rate of 8 Nm ³ / h. After 15 minutes, the flow rate of ethylene was lowered to 2 Nm ³ / h, and the pressure in the system was adjusted 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 / h for 3.5 hours while adjusting 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, after the inside of the system was replaced with nitrogen, the supernatant was removed and washed twice with hexane. In this way, a solid prepolymerized catalyst (2) in which 3 g of polymer was prepolymerized per 1 g of the solid catalyst component was obtained. This prepolymerized polymer had an intrinsic viscosity [η] of 2.1 dl / g and a 1-hexene content of 4.8% by weight.

[Preparation of catalyst slurry]
Mineral oil (Idemitsu Kosan Daphne Oil KP-68) and grease (CROMPTON CORP. WHITEPROTOPET 1-S) in a SUS container with an agitator of 1.1 m ³ under conditions of nitrogen atmosphere and atmospheric pressure 3: 7 was applied at a weight ratio, and the stirring apparatus was heated to 60 ° C. while stirring at 20 rpm. Before introducing the solid prepolymerized catalyst (2), diethylaluminum ethoxide as an organoaluminum compound was added at 1500 ppm per weight of the prepolymerized catalyst to be added (1.5 mg with respect to 1 g of the prepolymerized catalyst). Thereafter, the solid prepolymerized catalyst (2) was added so that the catalyst concentration was 55 to 80 g-cat / liter-solvent, and the mixture was cooled to 5 to 10 ° C. with stirring to prepare a catalyst slurry.

[Catalyst slurry supply]
The obtained catalyst slurry is transferred at a rate of 7 liters / hour using a catalyst transfer cylinder and a supply cylinder, and the pressure is increased to about 4 MPaG. Immediately before the polymerization reactor, mineral oil (Daphney oil KP-68 manufactured by Idemitsu Kosan Co., Ltd.) is added at a weight ratio of 0.5: 1 to the catalyst slurry to dilute the catalyst slurry, and the catalyst slurry is polymerized into the polymerization reactor. Supplied in. The stability of the catalyst supply was evaluated based on the response of the polymerization reactor.

  The polymerization reaction was stable after 4 days of continuous operation, and stable supply of the catalyst slurry was confirmed.

(Comparative Example 2)
In Example 2, a catalyst slurry was prepared in the same manner except that diethylaluminum ethoxide was not used when preparing the catalyst slurry, and the supply stability was evaluated.

  Under these conditions, the polymerization reaction became unstable after about 12 hours. When the catalyst supply device was opened and inspected, the solid prepolymerized catalyst was charged and adhered to the inside of the catalyst transfer cylinder and supply cylinder, the wall surface of the catalyst slurry storage container, the shaft of the stirring device, and the like.

The schematic flowchart of the olefin polymerization method of this invention is shown.

Claims (4)

When supplying a catalyst slurry containing a prepolymerized catalyst supported on a solid to a gas phase reactor for main polymerization of olefin,
An olefin polymerization method characterized by allowing 0.3 to 3.0 mg of an organoaluminum compound to accompany 1 g of the prepolymerized catalyst.   The polymerization method according to claim 1, wherein the olefin contains ethylene and / or propylene.   The polymerization method according to claim 1 or 2, wherein the organoaluminum compound is entrained immediately before the catalyst slurry is supplied to the gas phase reactor.   The polymerization method according to claim 1, wherein the catalyst slurry is immediately supplied to the gas phase reactor after the organoaluminum compound is entrained in the catalyst slurry.

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