JP2001098004A - Method for gas-phase polymerization of olefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for polymerizing an olefin wherein an olefin polymer can be manufactured continuously and stably for a long period of time by performing the olefin polymerization using an olefin polymerization catalyst and a fluidized-bed type gas-phase polymerizer. SOLUTION: This gas-phase olefin polymerization method is characterized in polymerizing an olefin using an olefin polymerization catalyst and a fluidized- bed type gas-phase polymerizer, wherein the temp. difference inside the fluidized- bed is measured and the linear gas velocity is controlled when the temp. difference reaches a specified value or thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an olefin polymerization catalyst, which is used to carry out olefin polymerization using a fluidized-bed gas-phase polymerization reactor.
The present invention relates to a method for polymerizing an olefin that can be stably produced for a long period of time.

More specifically, the temperature difference inside the fluidized bed during the gas phase polymerization of olefin is measured, and when the temperature difference reaches a predetermined value or after, the generation of heat spots is controlled by controlling the gas linear velocity. It relates to a polymerization method to prevent.

[0003] The terms "polymerization" and "polymer" used in the present specification refer to "homopolymerization" or "copolymerization" and "homopolymer" or "copolymer", respectively. It is used in the sense to include.

[0004]

2. Description of the Related Art An olefin polymer such as polyethylene or a linear low-density polyethylene (LLDPE) which is a copolymer of ethylene and an α-olefin is used as a material for forming a film. Widely used.

[0005] Such olefin polymers are produced using a Ziegler type or metallocene type catalyst. With recent improvements in transition metal catalysts for olefin polymerization,
The olefin polymer production capacity per unit amount of transition metal has been dramatically improved, and as a result, a catalyst removing operation after polymerization has been omitted.

[0006] When such a highly active catalyst is used, the polymerization operation is the simplest, and therefore, many methods for performing olefin polymerization in the gas phase have been adopted. In such a gas-phase polymerization, a fluidized-bed polymerization apparatus provided with a gas dispersion plate is often used in order to facilitate the polymerization. That is, an olefin or an olefin-containing gas is introduced into the lower part of the polymerization reactor through a supply pipe by a compressor or a blower, and then uniformly dispersed by a gas dispersion plate having a large number of holes formed therein, and the inside of the polymerization reactor is raised. The polymerization is carried out by flowing the catalyst particles in contact with the catalyst particles in the fluidized bed zone above the dispersion plate.

In this case, an olefin polymer is formed on the surface of the catalyst particles. Therefore, solid particles composed of the catalyst particles and the olefin polymer are suspended in the fluidized bed area, and the polymer is obtained in the form of particles. Can be. For this reason, a particle precipitation step or a particle separation step after the polymerization becomes unnecessary, so that the production process can be simplified and the production cost can be reduced. Further, since it does not contain a solvent or the like, a solvent removing step and a solvent refining step are not required, the equipment is further simplified, and the manufacturing cost can be further reduced.

Further, the unpolymerized gas is taken out from the upper part of the polymerization vessel, cooled with cooling water or brine, and then sent again to the lower part of the polymerization vessel by a compressor or a blower to be circulated and used. I have.

In order to stably and efficiently operate a fluidized bed polymerization vessel for performing the above-described gas phase polymerization for a long period of time, (1) prevention of a heat spot in a fluidized bed which is a polymerization zone of the gas phase polymerization. 2) Prevention of fusion of polymer particles in the fluidized bed (3) Prevention of non-flowable or poorly flowing polymer particles is required.

There are various causes for these problems, and in order to solve each of the causes, water, oxygen, alcohol, etc. are supplied to a fluidized bed reactor having a stirrer or a circulating gas. For example, techniques for impregnating a catalyst with an antistatic agent have been developed. However, not all the causes have been completely eliminated, and there is a need for a fluidized bed operation method that is more stable for a long period of time.

[0011]

As a conventional solution, an activity inhibitor is added directly to the reactor during catalyst preparation or polymerization in order to remove the cause of the formation of lumps mainly generated in the fluidized bed area. It was to supply or to remove generated deposits on the reactor wall by mechanical action. Although a certain result can be obtained by such a method, it has been desired that a metallocene catalyst system having high activity still be further improved. For example, the method of adding a catalyst activity inhibitor is very effective for a hot spot in which the catalyst component is presumed to have a partially highly active active site. It is difficult to cope with heat spots and the like generated due to non-uniformity of the powder flow caused by changes in the temperature while maintaining the catalytic activity. Even in such a case, it is simple and effective. There has been a demand for a method for preventing the generation of heat spots.

[0012]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of intensive studies to solve the above problems, the temperature difference between any two points inside the fluidized bed when performing olefin gas phase polymerization with a fluidized bed type phase polymerizer using a catalyst component for olefin polymerization. Or, when the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed becomes larger than the temperature difference between the two points during steady-state operation by 1 ° C. or more, or after that, the gas linear velocity in the fluidized bed is made steady. It has been found that the above-described problems can be solved by setting the gas linear velocity at 1.01 times to 1.5 times the time, and the present invention has been completed.

In the present invention, the olefin used for the gas phase polymerization is not limited, but is preferably an ethylene homopolymer or a copolymer of ethylene and C3 to C8, and has a density of 0.89 to 0.89. It is preferable when obtaining a resin of 0.98 g / cm ³ .

Further, the polymerization temperature is preferably from 20 to 200 ° C., and the polymerization pressure is preferably from 0.1 to 10 MPa. That is,
The present invention provides the following (1) to (3). (1) A method for carrying out olefin polymerization by a fluidized bed type gas phase polymerization reactor using an olefin polymerization catalyst, wherein the temperature difference between any two points inside the fluidized bed, or between the inside of the fluidized bed and the fluidized bed When the temperature difference in the upper part becomes larger than the temperature difference between the two points during the steady operation by 1 ° C. or more, the gas linear velocity is set to 1.01 of the gas linear velocity during the steady operation.
A gas-phase polymerization method for olefins, wherein the method is 1.5 times to 1.5 times. (2) Density of 0.89 g / cm ^{3 to} 0.98 g / c
A gas phase polymerization method for olefins, wherein the operation of (1) is performed by ethylene homopolymerization of m ³ and copolymerization of ethylene with an olefin having 3 to 8 carbon atoms. (3) A gas phase polymerization method for olefins, wherein the operation (1) or (2) is performed under the conditions of a polymerization pressure of 0.1 MPa to 10 MPa and a polymerization temperature of 20 ° C. to 200 ° C. In the present invention, the following embodiments are also preferred embodiments. Temperature difference between any two points inside the fluidized bed,
Or, when the temperature difference between the inside of the fluidized bed and the upper portion of the fluidized bed becomes larger than the temperature difference during the steady operation by 1 ° C. or more, or thereafter, the gas linear velocity is set to 1.01 times the gas linear velocity during the steady operation.
By changing the temperature difference by 1.5 times,
Lower than ° C. After the temperature difference between the two points becomes smaller than 1 ° C., the gas linear velocity may be changed to the gas linear velocity during steady operation. It is preferable that the temperature difference between any two points inside the fluidized bed, or the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed does not exceed 10 ° C. as compared with the temperature difference between the two points during steady operation. Is most preferably 4 ° C. so as not to exceed 5 ° C.
It is preferable to control the gas linear velocity in a range of 1.01 to 1.5 times the steady-state operation so as not to exceed.

When the gas linear velocity is varied, 0.0 mol / mol of organic aluminum supplied to the fluidized bed is used.
A catalyst deactivator of 1 to 1 mol / mol can be supplied from above the fluidized bed powder surface to between the gas circulation line.

After the temperature difference between all two points inside the fluidized bed and the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed no longer exceeds 1 ° C. with respect to the temperature difference during steady-state operation, the gas The linear velocity may be changed to the gas linear velocity during steady operation.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a fluidized-bed gas-phase polymerization method using the polymerization method of the present invention will be described more specifically. (Polymerizer) FIG. 1 shows an example of the structure of a fluidized-bed polymerizer equipped with the gas dispersion plate of the present invention. The polymerization vessel 1 has a straight body 1a.
A gas dispersion plate 2 is provided below the straight body portion 1a, and an internal space of the polymerization vessel 1 is vertically divided by the gas dispersion plate 2, and a gas phase polymerization is performed on the upper portion thereof. A fluidized bed region 3 is formed, and a gas introduction region 4 is formed below. In the gas phase polymerization vessel, the gas introduction area does not necessarily have to be one chamber, the gas introduction chamber is divided into several chambers, and a plurality of gas introduction paths are provided in a conical or abacus ball-shaped member. Alternatively, a gas introduction port in which a plurality of gas introduction lines are bundled may be provided. The fluidized bed reactor may be a straight body part, but in some cases, as shown in FIG. 1, a deceleration zone 7 may be provided at the upper part of the fluidized bed to reduce the gas velocity and prevent the particles from jumping out. . The deceleration region (up to the outlet of the gas circulation line when there is no deceleration region) from above the fluidized bed powder surface is referred to as a free board portion. In addition, the upper part of the fluidized bed in the present specification includes the deceleration region and the free board portion. In the fluidized bed area 3 of the polymerization vessel 1,
The catalyst supply pipe 5 and the produced polymer take-out pipe 6 are connected, and a gas discharge pipe 8 is further connected to the upper part. A deactivator supply nozzle 13 may be provided above the fluidized bed.

From the catalyst supply pipe, the solid catalyst and the organometallic compound catalyst component or, if necessary, each compound such as an electron donor are supplied to the gas phase polymerization reactor 1. Such a solid catalyst component can be supplied to a gas-phase polymerization reactor in the form of a dry solid powder or suspended in a hydrocarbon.When prepolymerizing an olefin, an organometallic compound catalyst component or If necessary, an electron donor is used, and these compounds are also supplied together with the prepolymerization catalyst.

A supply pipe 9 for a gas containing an olefin to be polymerized or, if necessary, a low-boiling non-polymerizable hydrocarbon or an inert gas together with the olefin is connected to the gas introduction zone 4. The gas introduced into the gas chamber 4 flows into the fluidized bed zone 3 through the gas dispersion plate 2,
The gas-phase polymerization is performed while flowing.

The polymerization system (fluidized bed) 3 can be mechanically stirred (not shown). The stirring can be performed using various types of stirrers such as an squid-type stirrer, a screw-type stirrer, and a ribbon-type stirrer.

The exhaust gas from the gas exhaust pipe 8 is cooled by the heat exchanger 10 to remove the heat of polymerization. In the heat exchanger 10, the circulating gas may be cooled until a part of the circulating gas forms a condensate as long as the stability of the fluidized bed is not impaired. After cooling, the circulating gas is separated into a condensate and a gas portion as necessary (not shown), and the condensate is pumped (not shown) as necessary. The gas is then circulated to the gas introduction area 4. The circulating gas may be passed through the cooler 10 via the blower 12.

The cooled circulating gas is introduced into the gas introduction area together with new gas supplied by the gas supply pipe 9 through the circulation line 11 to form a fluidized bed. The condensate may be supplied from the circulation line 11 to the polymerization reactor or from another line (not shown).

At this time, the olefin and / or the non-polymerizable hydrocarbon having a low boiling point are usually supplied in a gaseous state at a flow rate capable of maintaining the polymerization system 3 in a fluid state. Specifically, usually, when the minimum fluidization speed is U _mf , about 3 U
It is supplied at a flow rate of _{mf to} 50 U _mf . U _mf is usually represented by a gas linear velocity obtained by dividing a volume velocity of a gas passing through a fluidized bed by a sectional area. If the temperature, pressure, and cross-sectional area of the fluidized bed are constant, this gas linear velocity is the gas volume of the gas blown from the gas introduction area, that is, the gas flow newly supplied from the line 9 and the circulation pipe 11 to the polymerization reactor. It is determined by the sum of the supplied gas streams. The temperature inside the gas phase polymerization vessel may be any method as long as the temperature at the position where the measurement is required can be measured, but the following methods are known.

1) A method of installing a thermocouple or the like inside a reactor by intubation. As long as the installation does not hinder the stable operation of the fluidized bed, it is possible to attach the required number of parts to the site where measurement is required. Up to 5 points are provided in the free board section and the like.

2) A method of installing a surface thermometer on the outer surface of the reactor.

3) A method of measuring the reactor wall with a thermography measuring device. This method can measure two-dimensionally, and there are movable type and fixed type, but one or two (it goes without saying that there is no problem if it is more than necessary), the temperature distribution of the whole reactor Can be grasped. (Gas Passing Holes of Gas Dispersion Plate) A large number of gas passage holes are usually formed concentrically in the gas dispersion plate 2 used in the fluidized bed polymerization vessel 1, and gas is introduced through these passage holes. Gas flows from zone 4 to fluidized bed zone 3.

As described above, the gas dispersion plate does not need to be a simple flat plate as long as the gas can be dispersed so as to form a fluidized bed, and may be any of a concave lens, a convex lens, and a trapezoidal shape. A plurality of gas introduction paths may be provided in the ball-shaped member, or a gas introduction port in which a plurality of gas introduction lines are bundled may be provided. (Overcap of gas dispersion plate) In a fluidized bed reactor having a gas chamber, when the operation is stopped, the powder falls into the gas chamber, and when this is restarted, the dispersion plate is clogged or the gas introduction path is clogged. In such a case, an overcap may be provided.

Generally, an overcap is provided on the gas passage hole of the gas distribution plate 2 (not shown). By providing the overcap, it is possible to effectively prevent the powdery polymer or the like dropped from the fluidized bed region 3 from entering the gas passage hole.

The overcap has, for example, a shape (for example, a V-shape) expanding toward the outflow side of the gas flow from the overcap, and a swirling flow is formed in the same direction along the concentric circle of the gas passage hole. Are arranged as follows. (Polymerization conditions) In the above-mentioned gas-phase polymerization of olefins using the fluidized-bed type polymerization vessel 1, the olefins used preferably include α-olefins having 2 to 18 carbon atoms.

For example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene,
-Octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, isoprene, 1,4-hexadiene, butadiene, and the like.

Further, cyclopentene, cycloheptene,
Norbornene, 5-methyl-2-norbornene, dicyclopentadiene, 5-ethylidene-2-norbornene, tetracyclododecene, 2-methyl-1,4,5,8-dimethano-
Also included are 1,2,3,4,4a, 5,8,8a-octahydronaphthalene, styrene, vinylcyclohexane and the like. These are used alone or in combination as long as the gas phase polymerization is possible. Usually, homopolymerization of ethylene or propylene,
It is a copolymer of ethylene or propylene and another olefin, for example, having 3 to 8 carbon atoms. In that case, the density of the obtained resin is preferably in the range of 0.89 to 0.98 g / cm ³ . In addition, hydrogen gas can be used together with the olefin for the purpose of adjusting the molecular weight and the like.
In the main polymerization step, the polymerization conditions vary depending on the olefin to be polymerized and the flow state of the polymerization system (fluidized bed) 3, but usually the polymerization temperature is 20 to 200 ° C. and the polymerization pressure is
0.1 to 10 MPa. (Polymerization method) The gas phase polymerization method of the present invention refers to any one of two points inside a fluidized bed when performing a gas phase polymerization of olefin by a fluidized bed type gas phase polymerization reactor using a catalyst component for olefin polymerization. When the temperature difference between the two points or the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed increases by 1 ° C. or more as compared with the temperature difference between the two points during the steady operation, or thereafter, preferably 2 ° C. When or after that, the gas linear velocity in the fluidized bed is increased to 1.01 times the gas linear velocity during steady operation.
This is a polymerization method in which the gas linear velocity is changed to a range of 1.5 times, preferably 1.02 times to 1.3 times, and more preferably 1.03 times to 1.2 times. In the above method, the gas linear velocity may be changed once, but it is preferable to change the gas linear velocity intermittently or continuously within the above range until the temperature difference becomes smaller than 1 ° C. When intermittently varying here, the time interval for keeping the gas linear velocity constant is specifically 1/20 of the average residence time in the fluidized bed.
000 to 1/20 hour, preferably 1/5
More preferably, it is from 000 to 1/50. Further, the temperature difference between any two points inside the fluidized bed or the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed does not exceed 10 ° C. in comparison with the temperature difference between the two points during the steady operation. Preferably 5 ° C
, And most preferably the gas linear velocity is 1.01 to 1.5 times, preferably 1.02 to 1.3 times, more preferably 1 to 1 times the steady state operation so as not to exceed 4 ° C. .
Control is performed in the range of 03 times to 1.2 times.

The temperature difference between any two points inside the fluidized bed or the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed is 1 ° C. lower than the temperature difference between the two points during the steady operation. When the gas linear velocity is increased to 1.01 to 1.5 times that of the steady state operation, or after that, the temperature difference between all two points inside the fluidized bed, or After the temperature difference between the fluidized bed and the upper portion of the fluidized bed becomes 1 ° C. or less with respect to the steady operation, the gas linear velocity may be returned to the gas linear velocity during the steady operation.

The temperature at the two points inside the fluidized bed may be measured at any position, and the detected position may be at any position in the fluidized bed. The temperature, deceleration range or freeboard part is often used.
For example, when using a thermography or a surface thermometer, the wall temperature can be easily measured, and in controlling the temperature difference, the temperature difference between the walls at a site as far away as possible so that a significant difference can be measured, or any of the wall surfaces For example, a difference between the temperature and the temperature of the powder layer in the fluidized bed, or the temperature of the deceleration region or the freeboard portion may be used.

When the polymer adheres to the wall surface, which is one of the causes of the instability of the fluidized bed, the wall surface temperature usually becomes higher than the polymerization temperature, and the temperature difference inside the fluidized bed may increase. Many. Also in this case, the temperature difference between any two points inside the fluidized bed or the temperature difference between the inside of the fluidized bed and the upper part of the fluidized bed is 1 compared with the temperature difference between the two points during the steady operation.
By controlling the gas linear velocity of the fluidized bed so as not to be higher than ° C., prevention of adhesion of the polymer can be achieved and the operation of the polymerization reactor can be stabilized.

In the case of such wall adhesion, the wall temperature generally becomes higher than the polymerization temperature. In this case, one of the wall temperatures is separated from another wall surface at a site as far as possible so that a measurement having a significant difference can be performed. The difference between the temperature and the temperature difference between any of the wall surfaces and the upper part of the fluidized bed is 1
The operation can be stabilized by controlling the gas linear velocity of the fluidized bed at or after the temperature rises by at least ° C.

At this time, the gas linear velocity was set to 1.01 of the steady state.
After changing the gas linear velocity to the normal gas linear velocity after a certain period of time, the time required to return to the original gas linear velocity at this time generally depends on the powder in the fluidized bed. 1 of residence time
% To 100%, preferably 2%
Not less than 50%.

If the fluidized bed contains a large amount of fine powder, when the gas linear velocity is varied, 0.001 to 1 mol / mol of organic aluminum supplied to the fluidized bed is supplied.
It is preferable to supply mol catalyst deactivator from above the fluidized bed powder surface to the space between the gas circulation line because the free board portion, the deceleration region, and the gas circulation line can be prevented from being blocked. (Catalyst for polymerization) The catalyst used in the polymerization method of the present invention is not limited, and examples thereof include compounds of transition metals such as titanium, vanadium, chromium, zirconium, and hafnium. Can also be used. Further, these need not be a single compound, and may be supported on another compound, may be a homogeneous mixture with another compound, and may be a complex compound or a complex compound with another compound. There may be.

As a catalyst containing such a transition metal compound catalyst component, a metallocene catalyst known per se can be mentioned.

Hereinafter, the metallocene catalyst will be described.

A solid metallocene catalyst containing a catalyst component of a transition metal compound of Group IV of the periodic table (hereinafter sometimes simply referred to as Group IV) is a metallocene catalyst having an [A] cyclopentadienyl skeleton. Group IVB transition metal compound containing a ligand, [B] an organoaluminum oxy compound, and [C] a particulate carrier.

The [A] group IVB transition metal compound containing a ligand having a cyclopentadienyl skeleton (hereinafter sometimes referred to as a metallocene compound [A]) used in the present invention is represented by the following formula [I]: ].

ML _x ... [I] wherein M is a group IVB transition metal atom, specifically, zirconium, titanium or hafnium;
L is a ligand coordinating to the transition metal atom, and at least one L is a ligand including a ligand having a cyclopentadienyl skeleton, and is a ligand having a cyclopentadienyl skeleton. L other than the contained ligand is a hydrocarbon group having 1 to 12 carbon atoms, an alkoxy group, an aryloxy group, a trialkylsilyl group, an SO ₃ R group (where R may have a substituent such as halogen) A hydrocarbon group having 1 to 8 carbon atoms), a halogen atom or a hydrogen atom, and x is a valence of a transition metal atom. Examples of the ligand including a ligand having a cyclopentadienyl skeleton include, for example, cyclopentadienyl group, methylcyclopentadienyl group, dimethylcyclopentadienyl group, trimethylcyclopentadienyl group, tetramethyl Cyclopentadienyl group, pentamethylcyclopentadienyl group, ethylcyclopentadienyl group, methylethylcyclopentadienyl group, propylcyclopentadienyl group, methylpropylcyclopentadienyl group, butylcyclopentadienyl group And alkyl-substituted cyclopentadienyl groups such as methylbutylcyclopentadienyl group and hexylcyclopentadienyl group or indenyl group, 4,5,6,7-tetrahydroindenyl group, fluorenyl group and the like. . These groups may be substituted with a halogen atom, a trialkylsilyl group or the like.

Among the ligands which coordinate to these transition metal atoms, an alkyl-substituted cyclopentadienyl group is particularly preferred.

When the compound represented by the above general formula [I] contains two or more groups having a cyclopentadienyl skeleton, two of the groups having a cyclopentadienyl skeleton are ethylene and propylene. Alkylene groups such as,
The bond may be formed via a substituted alkylene group such as isopropylidene or diphenylmethylene, or a substituted silylene group such as a silylene group or a dimethylsilylene group, a diphenylsilylene group, or a methylphenylsilylene group.

Specific examples of the ligand L 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. More specifically, the alkyl group includes a methyl group, an ethyl group and a propyl group. Group, isopropyl group, butyl group, etc., as the cycloalkyl group, cyclopentyl group, cyclohexyl group, etc., as the aryl group, phenyl group, tolyl group, etc., and as the aralkyl group, a benzyl group. , A neofil group and the like.

As the alkoxy group, a methoxy group,
An ethoxy group, a butoxy group and the like are exemplified, an aryloxy group is exemplified by a phenoxy group and the like, and a halogen is exemplified by fluorine, chlorine, bromine and iodine.

As the ligand represented by SO ₃ R, p-
Examples thereof include a toluenesulfonato group, a methanesulfonato group, and a trifluoromethanesulfonato group.

The metallocene compound [A] containing such a ligand having a cyclopentadienyl skeleton has, for example, the following formula [I '] when the valence of the transition metal atom is 4, Is shown.

R ¹ _a R ² _b R ³ _c R ⁴ _d M [I ′] [In the formula [I ′], M is the same transition metal atom as in the formula [I], and R ¹ is cyclopentadienyl A group (ligand) having a skeleton; R ² , R ³ and R ⁴ are a group having a cyclopentadienyl skeleton, an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, an alkoxy group, an aryloxy group, An alkylsilyl group, a SO ₃ R group, a halogen atom or a hydrogen atom, a is an integer of 1 or more;
b + c + d = 4. In the present invention, in the formula [I ′], at least two of R ¹ , R ² , R ³ and R ⁴ , for example, R ¹ and R ² are groups (ligands) having a cyclopentadienyl skeleton. Metallocene compounds are preferably used.

These groups having a cyclopentadienyl skeleton include alkylene groups such as ethylene and propylene, substituted alkylene groups such as isopropylidene and diphenylmethylene, and silylene groups or substituted silylene groups such as dimethylsilylene, diphenylsilylene and methylphenylsilylene groups. It may be bonded via a group or the like.

R ³ and R ⁴ are a group having a cyclopentadienyl skeleton, 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 It is a hydrogen atom.

The following are specific examples of metallocene compounds wherein M is zirconium.

Bis (indenyl) zirconium dichloride, bis (indenyl) zirconium dibromide, bis (indenyl) zirconium bis (p-toluenesulfonato) 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, ethylene bis (indenyl) methyl zirconium monochloride, ethylene bis (Indenyl) zirconium bis (methanesulfonato), ethylenebis (indenyl) zirconium bis (p-toluenesulfonato), ethyl Bis (indenyl) zirconium bis (trifluoromethanesulfonato), ethylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadiene) Enyl-methylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (cyclopentadienyl) zirconium dichloride, dimethylsilylenebis (methylcyclopentadienyl) zirconium dichloride, dimethylsilylenebis (dimethylcyclopentadienyl) zirconium dichloride, dimethyl Silylene bis (trimethylcyclopentadienyl) zirconium dichloride, dimethyl silylene bis (indenyl) zirconium dichloride Dimethylsilylenebis (indenyl) zirconiumbis (trifluoromethanesulfonato), dimethylsilylenebis (4,5,6,7-tetrahydroindenyl) zirconium dichloride, dimethylsilylene (cyclopentadienyl-fluorenyl) zirconium dichloride, diphenyl Silylene bis (indenyl) zirconium dichloride, methylphenylsilylene bis (indenyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis (cyclopentadienyl)
Methyl zirconium monochloride, bis (cyclopentadienyl) ethyl zirconium monochloride, bis (cyclopentadienyl) cyclohexyl zirconium monochloride, bis (cyclopentadienyl) phenyl zirconium monochloride, bis (cyclopentadienyl)
Benzyl zirconium monochloride, bis (cyclopentadienyl) zirconium monochloride monohydride, bis (cyclopentadienyl) methyl zirconium monohydride, bis (cyclopentadienyl) dimethyl zirconium, bis (cyclopentadienyl) diphenyl zirconium, Bis (cyclopentadienyl) dibenzyl zirconium, bis (cyclopentadienyl)
Zirconium methoxy chloride, bis (cyclopentadienyl) zirconium ethoxycyclolide, bis (cyclopentadienyl) zirconium bis (methanesulfonato), bis (cyclopentadienyl) zirconium bis (p-toluenesulfonato), bis (cyclo (Pentadienyl) zirconium bis (trifluoromethanesulfonato), bis (methylcyclopentadienyl) zirconium dichloride, bis (dimethylcyclopentadienyl)
Zirconium dichloride, bis (dimethylcyclopentadienyl) zirconium ethoxycyclolide, bis (dimethylcyclopentadienyl) zirconium bis (trifluoromethanesulfonato), bis (ethylcyclopentadienyl) zirconium dichloride, bis (methylethylcyclopentadiyl) Enyl) zirconium dichloride, bis (propylcyclopentadienyl) zirconium dichloride, bis (methylpropylcyclopentadienyl)
Zirconium dichloride, bis (butylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium dichloride, bis (methylbutylcyclopentadienyl) zirconium bis (methanesulfonato), bis (trimethylcyclopentadienyl) ) Zirconium dichloride, bis (tetramethylcyclopentadienyl) zirconium dichloride,
Bis (pentamethylcyclopentadienyl) zirconium dichloride, bis (hexylcyclopentadienyl)
Zirconium dichloride, bis (trimethylsilylcyclopentadienyl) zirconium dichloride.

In the above examples, disubstituted cyclopentadienyl ring includes 1,2- and 1,3-substituted, and tri-substituted is 1,2,3- and 1,2,4-substituted. Including the body. Alkyl groups such as propyl and butyl are represented by n
-, Iso-, sec- and tert-.

In the present invention, as the metallocene compound [A], a compound in which zirconium in the above-described zirconium compound is replaced with titanium or hafnium can also be used.

These compounds may be used alone,
Two or more kinds may be used in combination. It may be diluted with a hydrocarbon or a halogenated hydrocarbon before use.

In the present invention, as the metallocene compound [A], a zirconocene compound having a ligand in which the central metal atom is zirconium and having at least two cyclopentadienyl skeletons is preferably used.

Specific examples of the organoaluminum oxy compound [B] used in the present invention include conventionally known aluminoxane and benzene-insoluble aluminum oxy compound as disclosed in JP-A-2-276807. Can be

Such a conventionally known aluminoxane can be produced from the following [B-2] organoaluminum compound by, for example, 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,
A method in which an organoaluminum compound such as trialkylaluminum is added to a hydrocarbon medium in which cerous chloride hydrate or the like is suspended and reacted to recover as a hydrocarbon solution. (2) A method in which water (water, ice or water vapor) is allowed to directly act on an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, ethyl ether, or tetrahydrofuran to recover a solution of the medium. (3) A method in which an organoaluminum compound such as trialkylaluminum is reacted with an organotin oxide such as dimethyltin oxide or dibutyltin oxide in a medium such as decane, benzene or toluene.

The solvent or unreacted organoaluminum compound may be removed from the recovered aluminoxane solution by distillation and then redissolved in the solvent.

The organic aluminum oxy compound [B] used in the present invention may contain a small amount of a metal component other than aluminum.

The organoaluminum oxy compound [B] is used in an amount of usually 5 to 1000 mol, preferably 10 to 400 mol, per 1 mol of the solid metallocene catalyst (in terms of transition metal atom). It is desirable.

As the particulate carrier [C] used in the present invention,
Specifically, specifically, SiO_Two, Al_TwoO _Three, B_TwoO_Three, Mg
O, ZrO_Two, CaO, TiO_Two, ZnO, Zn_TwoO, S
nO_Two, BaO, ThO and other inorganic carriers, polyethylene
, Polypropylene, poly-1-butene, poly-4-methyl
Ru-1-pentene, styrene-divinylbenzene copolymer
A resin (organic carrier) such as a body can be used. this
Among them, SiO_TwoIs preferred. These are two or more
It can also be used in combination.

The solid group IVB metallocene catalyst used in the present invention is prepared by supporting the above-mentioned [A] metallocene compound and [B] organoaluminum oxy compound on a [C] particulate carrier by a conventionally known method. Formed.

The solid group IVB metallocene catalyst is
Along with [A] a metallocene compound and [B] an organoaluminum oxy compound, the following [B-2] organoaluminum compound may be supported on a [C] particulate carrier.

In preparing the solid group IVB metallocene catalyst, [A] the metallocene compound (in terms of transition metal atom) is usually [C] 0.001 per gram of the particulate carrier.
To 1.0 mmol, preferably 0.01 to 0.5 mmol, and [B] the organoaluminum oxy compound is generally used in an amount of 0.1 to 100 mmol, preferably 0.5 to 20 mmol. .

The solid metallocene catalyst particles used in the present invention have a particle size of 1 to 300 μm, preferably 10 to 300 μm.
Preferably, it is 100 μm.

The solid metallocene catalyst used in the present invention may contain, if necessary, other components useful for olefin polymerization, such as an electron donor and a reaction aid, in addition to the above-mentioned catalyst components. Good.

In the solid metallocene catalyst used in the present invention, the solid metallocene catalyst as described above may be preliminarily polymerized with an olefin.

The solid group IVB metallocene catalyst used in the present invention can (co) polymerize an olefin with excellent polymerization activity.

In the present invention, olefin polymerization is carried out using the solid metallocene catalyst as described above.
At the time of polymerization, the following organic aluminum compound (B-2) can be used together with the solid group IVB metallocene catalyst.

The organoaluminum compound used as the [B-2] organoaluminum compound in the present invention and also used for producing the above-mentioned [B] aluminoxane solution is, specifically, Trimethylaluminum, triethylaluminum, tripropylaluminum, triisopropylaluminum, trin-butylaluminum, triisobutylaluminum, trise
trialkylaluminum such as c-butylaluminum, tritert-butylaluminum, tripentylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, tricyclohexylaluminum, tricyclooctylaluminum, dimethylaluminum chloride, diethylaluminum chloride, diethyl Aluminum bromide, dialkyl aluminum halides such as diisobutyl aluminum chloride, diethyl aluminum hydride,
Examples thereof include dialkylaluminum hydrides such as diisobutylaluminum hydride, dialkylaluminum alkoxides such as dimethylaluminum methoxide and diethylaluminum ethoxide, and dialkylaluminum aryloxides such as diethylaluminum phenoxide.

Of these, trialkylaluminum is preferred, and triethylaluminum and triisobutylaluminum are particularly preferred.

As the organoaluminum compound, isoprenylaluminum represented by the following general formula can also be used.

(I-C ₄ H ₉ ) _x Al _y (C ₅ H ₁₀ ) _z (where x, y, and z are positive numbers and z ≧ 2x). May be combined.

The [B-2] organoaluminum compound used in the present invention may contain a small amount of a metal component other than aluminum.

When the above [B-2] organoaluminum compound is supplied to the reaction system separately from the solid metallocene catalyst, it is usually added to 1 mol of the solid metallocene catalyst (in terms of transition metal atoms). It is desirable to use it in an amount of 1 to 1000 mol, preferably 2 to 300 mol.

When the organic aluminum compound [B-2] is supported on the particulate carrier [C] together with the metallocene compound [A] and the organic aluminum oxy compound [B], a solid metallocene catalyst (transition metal) is used. It is usually used in an amount of 1 to 300 mol, preferably 2 to 200 mol, per 1 mol of atom. (Deactivator) Examples of the deactivator used in the present invention include carbon monoxide, carbon dioxide, oxygen, water, alcohols having 1 to 6 carbon atoms, ketones having 1 to 6 carbon atoms, and It is preferred to use at least one selected from aldehydes having 1 to 6 carbon atoms and which is gaseous under gas phase polymerization conditions.

The quenching agent is supplied at a constant molar ratio to the organoaluminum supplied to the fluidized bed, and it varies depending on the catalyst system used. 0 / mol.
A quantity of 001 to 1 mol / mol of catalyst deactivator is provided. Here, the organoaluminum supplied to the fluidized bed is the sum of the organoaluminum compound contained as a catalyst component and the organoaluminum compound supplied simultaneously with the catalyst component, and includes an organoaluminum oxy compound.

[0081]

The present invention will be described below in more detail with reference to examples. The description of the following examples, etc.
This is an explanation for assisting the understanding of the contents of the present invention, and is not a character that is a basis for interpreting the technical scope of the present invention narrowly. The methods for measuring the physical properties measured in the following examples are as follows. (1) Melt flow rate (MFR) ASTM D12 was prepared using granulated pellets of a copolymer.
It is measured under the conditions of 190 ° C. and 2.16 kg weight according to 38-65T. (2) Bulk density Measured according to ASTM D-1895. Example 1 Using a continuous fluidized-bed gas-phase polymerization apparatus, total pressure: 2.0 MPa-G, polymerization temperature: 80 ° C., gas linear velocity: 80 c
At m / sec, ethylene and hexene-1 were copolymerized. Prepolymerized metallocene type solid polymerization catalyst 60
g / hr (0.5 mmol / h in terms of transition metal Zr metal)
r) was continuously supplied, and ethylene, hexene-1, hydrogen and nitrogen were continuously supplied to maintain the gas composition during the polymerization (the supply amounts of the respective components were as follows: ethylene = 70N)
m ³ / hr; hexene-1 = 14 L / hr; hydrogen = 5N
L / hr; nitrogen = 10 Nm ³ / hr). Under these conditions, the density is 0.915 g / cm ³ and the MFR is 0.5 g / cm ³ .
10 kg of ethylene / hexene copolymer of 70 kg /
hr. The residence time at this time was 5 hours.

After operating for 12 hours under these conditions, the temperature difference between the fluidized bed wall surface and the inside of the fluidized bed was 3 ° C. Therefore, the gas linear velocity was maintained at 85 cm / sec for 20 minutes, and when the temperature difference became 1 ° C. or less, the gas linear velocity was returned to that at the time of steady operation.

During the continuous operation for 24 hours from the start of the polymerization,
The temperature difference occurred twice, but in each case, the temperature difference was eliminated by the method described above.

After the operation was completed for 24 hours, the polymerization reactor was opened. When the polymerization reactor was opened, no sheet or lump was observed in the reactor. Comparative Example 1 Even when a temperature difference was observed, polymerization was carried out in the same manner as in Example 1, except that the operation was performed without changing the gas linear velocity. As a result, four hours after the rise in the fluidized bed wall surface temperature, the operation could not be continued due to the formation of the sheet-like polymer.

[0085]

According to the olefin polymerization method of the present invention, the generation of polymer lumps and the generation of a sheet-like polymer above the fluidized bed powder surface of a gas phase polymerization apparatus can be suppressed or prevented, and the olefin polymerization can be performed for a long time. To carry out gas phase polymerization. In particular, it can quickly respond to non-uniformity of powder flow, etc., achieves stabilization of the fluidized bed without the need for new equipment, and without fear of deactivating the catalyst or shortening the catalyst life. Was completed.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a gas-phase polymerization apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polymerizer 2 Dispersion plate 3 Fluidized bed area 4 Gas introduction area 5 Catalyst supply pipe 6 Polymer take-out pipe 7 Deceleration area 8 Gas extraction pipe 9 Gas supply pipe 10 Heat exchanger 11 Circulation pipe 12 Blower 13 Deactivator supply nozzle

Claims (3)

[Claims] 1. A method for carrying out olefin polymerization by a fluidized-bed gas-phase polymerization reactor using an olefin polymerization catalyst, wherein a temperature difference at any two points inside the fluidized bed, When the temperature difference in the upper part of the fluidized bed increases by 1 ° C. or more compared to the temperature difference between the two points in the steady operation, or thereafter, the gas linear velocity is set to 1.01 to the gas linear velocity in the steady operation.
A method for gas phase polymerization of olefins, wherein the method is 1.5 times. 2. Density of 0.89 g / cm ^{3 to} 0.98
g / cm ³ of ethylene homopolymer and ethylene and carbon number 3
A method for gas phase polymerization of olefins, wherein the operation of claim 1 is carried out by copolymerization with olefins of (8) to (8). 3. A polymerization pressure of 0.1 MPa to 10 MPa,
3. The method according to claim 1, wherein the polymerization temperature is 20 ° C. to 200 ° C.
A gas phase polymerization method for olefins, comprising the steps of: