JP2011116970A - Propylene polymerization reaction apparatus and manufacturing method for propylene based polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a propylene polymerization reaction apparatus capable of stably manufacturing a continuous multi-stage polymer in high productivity at low cost and outstandingly reducing the generation amount of a non-standardized product accompanying with change of a polymerization condition in a multi-stage continuous vapor-phase polymerization method for the propylene based polymer using an olefin polymerization catalyst, and a manufacturing method for a propylene based polymer. <P>SOLUTION: The reaction apparatus for manufacturing the propylene based polymer by the multi-stage continuous vapor-phase polymerization method includes at least one lateral type reaction tank having an agitator rotated around a horizontal axis inside and at least one complete mixing tank connected to the lateral type reaction tank. The manufacturing method for the propylene based polymer uses the apparatus. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a propylene polymerization reactor and a method for producing a propylene polymer, and more particularly, in a multistage continuous gas phase polymerization method of a propylene polymer using an olefin polymerization catalyst, with low cost and high productivity. The present invention relates to a propylene polymerization reaction apparatus and a method for producing a propylene-based polymer, which can stably produce a continuous multistage polymer and can greatly reduce the amount of non-standard products generated by changing the polymerization conditions.

  Polypropylene resins have been used in various fields since they are relatively inexpensive and have excellent properties. However, various improvements have been added to polypropylene itself because its use is limited. For example, in order to improve impact resistance, homopolypropylene is first polymerized and then propylene-based block copolymer obtained by copolymerization of propylene and ethylene, or polypropylene with different molecular weights to improve moldability and appearance. Propylene-based polymers having a molecular weight distribution that has been manufactured by a conventional method have been proposed.

  In the production of these resins, there is a method in which each component is manufactured individually and then kneaded again at a predetermined ratio, but each component is continuously added due to economic concerns and the risk of quality deterioration due to kneading. A continuous multi-stage polymerization process is preferred. However, since the polymer particles are almost completely mixed in one container, it is easy for the particles that are not sufficiently grown to be discharged and the particles that have grown too much to accumulate in the container. As a result, the quality of the polymer is deteriorated. On the other hand, it is conceivable that a plurality of completely mixed reaction vessels are connected in series to form a plug flow as a whole, but providing a large number of reaction vessels requires equipment costs.

  A known horizontal reactor having a stirrer that rotates about a horizontal axis is known as a known reactor that achieves plug flow by reducing the residence time distribution in one reaction tank (a horizontal gas phase process, for example, Patent Document 1. Hereinafter, the reactor is also referred to as a reaction vessel). In general, the catalyst particles gradually grow into polymer particles due to the polymerization reaction, but when polymerization is performed in a horizontal reactor, these particles gradually grow due to the two forces of formation of polypropylene by polymerization and mechanical stirring. It progresses along the axial direction of the reactor while growing. For this reason, the particles having the same degree of growth, that is, the residence time are aligned with time from the upstream side to the downstream side of the reactor. That is, in the horizontal reactor, the fluid flow pattern is a plug flow type, which has the effect of narrowing the residence time distribution to the same extent as when a plurality of fully mixed reaction tanks are arranged in series. Therefore, in the production of the polymer, a propylene polymerization reactor comprising a plurality of horizontal reactors connected in series is advantageous.

  By the way, when the purpose is to modify the polypropylene shown in the above-described example, a component having a low molecular weight or a component having a large amount of components such as ethylene is produced in a certain polymerization step. In the horizontal reactor, the latent heat of liquefied propylene is used to remove the heat of polymerization. As the liquefied propylene, there is a case where unreacted propylene gas is extracted from the polymerization reaction tank and liquefied by cooling with a heat exchanger. The temperature (dew point) at which the unreacted gas liquefies depends on the pressure and the composition of the unreacted gas. The dew point decreases as the mixing amount increases. As a result, in a process including a horizontal reactor, when an attempt is made to produce a multistage polymer containing a component having a low molecular weight or a component such as ethylene, there arises a problem that the productivity is remarkably lowered due to the problem of heat removal.

  In order to solve the above problem, there is a method of increasing the cooling capacity of the heat exchanger, but in this case, the equipment cost is very high. Even if a heat exchanger having a considerable capacity is installed, a large amount of energy is required for its operation.

  As described above, the horizontal gas phase process has excellent plug flow characteristics, but productivity and operation cost are required when producing a multistage polymer having a low molecular weight component or a component containing a large amount of ethylene. Have problems to be solved.

Japanese Patent No. 2675919

  An object of the present invention is to provide a continuous multistage polymer stably at a low cost and with high productivity in a multistage continuous gas phase polymerization method of a propylene-based polymer using an olefin polymerization catalyst in view of the above-mentioned problems of the prior art. It is an object to provide a propylene polymerization reactor and a propylene-based polymer that can greatly reduce the amount of non-standard products generated by changing polymerization conditions.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors, in a reaction apparatus for producing a propylene-based polymer by a multistage continuous gas phase polymerization method, a horizontal reaction tank, a complete mixing tank connected thereto, It is found that the above-mentioned problems can be solved by producing a propylene polymerization reaction apparatus comprising at least one tank, and further by a method for producing a propylene polymer using the same. It came to complete.

  That is, according to the first invention of the present invention, a reaction apparatus for producing a propylene-based polymer by a multistage continuous gas phase polymerization method, which has a stirrer that rotates about a horizontal axis therein. And at least one complete mixing tank connected to the horizontal reaction tank, respectively, is provided.

  According to a second aspect of the present invention, in the first aspect, the complete mixing tank is a reaction tank that mainly removes the heat of polymerization using sensible heat of the circulating gas. A propylene polymerization reactor is provided.

  According to a third invention of the present invention, in the first or second invention, the complete mixing tank is a reaction tank selected from a vertical stirring tank, a stirring fluidized bed reaction tank, or a fluidized bed reaction tank. A propylene polymerization reactor characterized by the above is provided.

  According to a fourth aspect of the present invention, there is provided a propylene polymerization reaction apparatus according to the first or second aspect, wherein the complete mixing tank is a fluidized bed reaction tank.

  According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the horizontal reaction tank has an L / D of 5 or more (L: length in the horizontal longitudinal direction, D: inner diameter). A propylene polymerization reactor characterized by the above is provided.

  According to a sixth aspect of the present invention, there is provided the propylene polymerization reaction apparatus according to any one of the first to fifth aspects, wherein the complete mixing tank is provided immediately after the horizontal reaction tank. Is done.

  According to the seventh invention of the present invention, the multistage continuous gas phase polymerization of propylene is carried out in the presence of an olefin polymerization catalyst using the propylene-based polymerization reaction apparatus according to any one of the first to sixth inventions. A method for producing a propylene-based polymer is provided.

  According to an eighth aspect of the present invention, in the seventh aspect, the polymerization reaction in the complete mixing tank is performed using a reaction gas having a dew point of 50 ° C. or lower. A manufacturing method is provided.

  According to the ninth invention of the present invention, in the seventh or eighth invention, the polymerization reaction of propylene is carried out in the horizontal reaction vessel, and subsequently, the α-olefin containing propylene and ethylene in the complete mixing vessel. Provided is a method for producing a propylene polymer, characterized by carrying out a polymerization reaction.

According to the apparatus and the production method of the present invention, a continuous multistage polymer of propylene-based polymer can be produced at a minimum equipment investment cost and stably maintaining high productivity.
In addition, in multistage continuous gas phase polymerization, when the residence time is changed in a specific gas phase polymerization reactor, the adjustment becomes very easy (short time), resulting in the generation of non-standard products due to changes in polymerization conditions. The amount can be greatly reduced.

FIG. 1 is a schematic view showing a flow sheet of a propylene polymerization reactor in which a horizontal reaction tank and a stirring fluidized bed reaction tank are combined in the present invention. FIG. 2 is a schematic view showing a flow sheet of a propylene polymerization reactor in which a horizontal reaction tank and a vertical stirring tank are combined in the present invention. FIG. 3 is a schematic diagram showing a flow sheet of a propylene polymerization reactor in which a horizontal reaction vessel and a fluidized bed reaction vessel are combined in the present invention. FIG. 4 is a schematic diagram showing a process flow of a preferred embodiment when a horizontal reaction vessel and a fluidized bed reaction vessel are combined in the present invention, and a flow sheet of the production method used in the examples.

1, 2 Catalyst component supply piping 3, 5 Raw material propylene supply piping 4, 6 Raw material supply piping (hydrogen, ethylene, etc.)
7 Electron donating compound supply pipe 10 Horizontal reactor (first stage polymerization process)
DESCRIPTION OF SYMBOLS 11 Gas-liquid separation tank 12 Reaction tank upstream end 13,23 Unreacted gas extraction piping 14 Reaction tank downstream end 15 Condenser 16,26 Compressor 17 Raw material liquefied propylene supply piping 18 Raw material mixed gas supply piping 20 Complete mixing tank (2nd Stage polymerization process)
25 Circulating gas cooler 30, 31 Degassing tank 32, 33 Polymer extraction piping 34 Polymer supply piping

The propylene polymerization reaction apparatus of the present invention is a reaction apparatus for producing a propylene-based polymer by a multistage continuous gas phase polymerization method, and has a horizontal reaction tank having a stirrer rotating around a horizontal axis therein, and the horizontal type At least one or more complete mixing tanks connected to the reaction tank are provided.
The method for producing a propylene polymer of the present invention is a method for producing a propylene polymer using the above-mentioned propylene polymerization reactor, wherein propylene multistage continuous gas phase polymerization is carried out in the presence of an olefin polymerization catalyst. It is characterized by performing.
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as necessary. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

<Propylene polymerization reactor>
The propylene polymerization reaction apparatus of the present invention is a reaction apparatus for producing a propylene-based polymer by a multistage continuous gas phase polymerization method, and has a horizontal reaction tank having a stirrer rotating around a horizontal axis therein, and the horizontal type At least one or more complete mixing tanks connected to the reaction tank are provided. Examples of the apparatus with the minimum reaction vessel configuration of the present invention are shown in FIGS.

<Horizontal reaction tank>
As the horizontal reaction tank constituting the propylene polymerization reaction apparatus of the present invention, a known reaction tank can be used as long as it is a horizontal reaction tank having a stirrer rotating around a horizontal axis. As an example, a horizontal reaction tank as shown in FIGS. 1 to 3 can be used.
1 to 3, a horizontal reaction tank 10 having a stirrer that rotates around a horizontal axis and is used in at least one tank is elongated and has an upstream end 12 and a downstream end 14. As shown in FIG. Is installed in a horizontal position. The shaft 8 extends into the downstream end 14 of the reaction vessel 10, and a blade for stirring is attached in the reaction vessel 10. The stirring blade mixes the polymer particles with other substances introduced into it in the reaction vessel 10.
The catalyst components introduced from the upstream pipes 1 and 2 of the reaction tank 10 start polymerization while being mixed with the polymer particles by the stirring blade. The polymerization heat generated during the polymerization is removed by the latent heat of evaporation of the raw material liquefied propylene supplied from the top pipe 17. Unreacted propylene gas is discharged out of the reaction system through the pipe 13, part of which is condensed in the condenser 15, and separated into a liquid phase and a gas phase in the gas-liquid separation tank 11. The liquid phase part is introduced into the pipe 17 for removing the polymerization heat, and the gas phase part is mixed with hydrogen or the like for molecular weight adjustment and supplied via the pipe 18 installed at the bottom of the reaction vessel 10.

  The L / D of the horizontal reaction tank in the present invention is preferably 3 or more, more preferably 5 or more, and preferably 10 or less. L is the length of the reaction tank in the horizontal longitudinal direction, and D is the inner diameter of the reaction tank. When L / D is too small, there is a possibility that sufficient narrowing of the residence time distribution cannot be achieved. On the other hand, when L / D is excessive, it is necessary to make the stirring shaft thicker in terms of strength, and the actual reaction volume may decrease and productivity may decrease.

<Complete mixing tank>
The “complete mixing tank” in the present invention means a reaction tank characterized in that when a substance in the tank flows in and out, the concentration in the tank is equal to the concentration of the effluent flow. That is, the complete mixing tank is advantageous in terms of the uniformity of the quality of the substance produced in the reaction tank because the temperature in the tank and the composition of the reaction gas are uniform.
As the complete mixing tank constituting the apparatus for producing the propylene polymer of the present invention, a known reaction tank can be used as long as it is the complete mixing tank as described above. Examples of the complete mixing tank widely used as a propylene polymerization apparatus include a vertical stirring tank, a stirring fluidized bed reaction tank, and a fluidized bed reaction tank. As an example, a complete mixing tank as shown in FIGS. FIG. 1 shows an example in which a stirred fluidized bed reaction tank is used as a complete mixing tank, a vertical stirred tank is used in FIG. 2, and a fluidized bed reaction tank is used in FIG.
The complete mixing tank used in the present invention is preferably a reaction tank characterized in that the polymerization heat is removed mainly by sensible heat of the circulating gas. Here, the reaction gas (reaction zone gas) and the circulation gas (circulation zone gas) in the continuous multistage gas phase polymerization method using the complete mixing tank of the propylene-based polymer include propylene and ethylene which are the aforementioned raw materials. α-olefin, hydrogen and other raw materials.
In the continuous multistage gas phase polymerization method, when the production is carried out under polymerization conditions where the dew point of the reaction gas is low, it is difficult to remove heat in the horizontal reaction tank, and the productivity is remarkably lowered. Although depending on the balance of the reaction amount of each stage and the ability of the heat exchanger in the continuous multistage polymerization, when the dew point of the reaction gas is less than 50 ° C., the productivity is significantly reduced. As an optimum polymerization reaction tank in a portion where such a polymerization environment is required, a reaction tank that mainly uses sensible heat of the circulating gas is used. The reaction tanks that are widely used include a stirred fluidized bed reaction tank and a fluidized bed reaction tank. In the present invention, the use of a fluidized bed reaction tank is preferred in terms of control of residence time and uniform dispersion of the polymer. Is more desirable. The reaction tank uses the sensible heat of the circulating gas to remove the heat of polymerization, and therefore is not affected by productivity due to a decrease in the dew point of the reaction gas.

As an example of the apparatus of the present invention, FIG. 3 shows a flow diagram of an apparatus using a fluidized bed reaction tank. The fluidized bed reaction tank 20 is elongated in the vertical direction, and the polymer produced in the previous step is supplied from the pipe 34. The polymer in the fluidized bed reaction tank 20 is fluidized with raw material propylene and other raw material gases such as hydrogen and ethylene supplied to the reaction tank at a linear velocity equal to or higher than the minimum fluidization rate, and a polymerization reaction is performed. . The unreacted mixed gas is extracted out of the reaction system through an unreacted gas extraction pipe 23, cooled by a circulating gas cooler 25, and supplied to the reaction tank 20 as a fluidizing gas.
The polymer produced in the reaction tank 20 is transferred to the next process via the pipe 33 and the degassing tank 31.

<Device configuration>
With regard to providing high productivity of the continuous multistage gas phase polymerization method according to the present invention, there is no limitation on the order of installation as long as it is an apparatus in which a horizontal reaction tank and a complete mixing tank are connected. About an installation order, it can carry out with any of a horizontal reaction tank-complete mixing tank and a complete mixing tank-horizontal reaction tank. Further, in the present invention, it is sufficient that at least one apparatus in which a horizontal reaction tank and a complete mixing tank are connected in a series of manufacturing steps, and other apparatuses may be arranged before and after this apparatus. Specifically, one or a plurality of additional polymerization reaction tanks such as a horizontal reaction tank or a reaction tank that mainly uses sensible heat of the circulating gas are provided in the front stage or the rear stage to realize an apparatus comprising three or more reaction tanks. May be. The configuration of such an apparatus includes a horizontal reaction tank-horizontal reaction tank-complete mixing tank, horizontal reaction tank-complete mixing tank-complete mixing tank, horizontal reaction tank-horizontal reaction tank-complete mixing tank-complete mixing tank, and the like. Can be mentioned.

However, in order to reduce the amount of non-standard product generated when changing the residence time in the reaction tank using the sensible heat of the circulating gas, it is preferable to dispose the complete mixing tank immediately after the horizontal reaction tank. In an apparatus including a plurality of horizontal reaction tanks and / or complete mixing tanks, the apparatus preferably includes a configuration in which the complete mixing tank is disposed immediately after the horizontal reaction tank.
In the case of a continuous multistage gas phase polymerization method, the reaction amount can be controlled in each stage of the polymerization process. In general, when it is desired to suppress the reaction amount in a certain polymerization step, a small amount of a polymerization deactivator is supplied to control the reaction amount. However, the use of an excessive polymerization deactivator greatly reduces the reaction amount in the next step. End up. Therefore, in order to control the reaction amount in the continuous multistage gas phase polymerization method, it may be necessary to change the propylene partial pressure or the residence time in the reaction tank depending on the use of the polymerization deactivator.

  For example, when there is no horizontal reaction tank in the previous stage of the complete mixing tank, as a specific example, as a reaction tank mainly utilizing sensible heat of the circulating gas, a fluidized bed reaction tank that is a complete mixing tank is used. In the case where there is no horizontal reaction tank in the front stage of the fluidized bed reaction tank, polymer particles that have received a history with a wide residence time distribution are supplied to the fluidized bed reaction tank. The particle size distribution of the polymer particles is wide. Under such circumstances, when changing the propylene partial pressure in the fluidized bed reactor or changing the amount of polymer retained in the reactor, the amount of circulating gas should be such that small particles of polymer do not scatter outside the system. It is necessary to carry out gradually while adjusting, resulting in a large amount of non-standard products.

  On the other hand, when there is a horizontal reaction tank in the previous stage of the complete mixing tank, as a specific example, when a horizontal reaction tank is installed in the previous stage of the fluidized bed reaction tank, the polymer particles supplied to the fluidized bed reaction tank The diameter distribution is narrow (there are few small particles), and the conditions can be changed in a shorter time than in the case described above. This effect was recognized for the first time by placing a complete mixing tank immediately after the horizontal reaction tank.

The apparatus of the present invention is an apparatus that exhibits the highest effect when producing a polymer component having a low molecular weight polypropylene component or a high concentration ethylene component in the polymer component.
For example, when producing homopolypropylene with an expanded molecular weight distribution, a component with a high molecular weight is produced in a horizontal reaction tank, and a component with a low molecular weight is subsequently produced in a complete mixing tank, which is a reaction tank that mainly uses sensible heat of the circulating gas. When the fluidized bed reaction tank is used as a complete mixing tank, the generation of non-standard products can be minimized.

As another example, in the production of propylene / ethylene copolymer, propylene / ethylene / 1-butene copolymer, and the like, copolymers having greatly different ethylene contents can be suitably produced in each polymerization step. In particular, it is suitable for production of a propylene-based block copolymer, and examples of the copolymer include propylene-propylene / ethylene block copolymer, propylene / ethylene-propylene / ethylene block copolymer, and the like. Can do.
In the case of the production of propylene-propylene / ethylene block copolymer, the homopolypropylene component is produced in a horizontal reaction tank, and then propylene / ethylene copolymer is mainly used in a complete mixing tank that is a reaction tank that utilizes sensible heat of circulating gas. By producing the coalescence component, high productivity can be obtained, and when a fluidized bed reaction vessel is used as a complete mixing vessel, generation of non-standard products can be minimized when the conditions are changed.

  In the apparatus of the present invention, as apparatuses other than reaction tanks such as a horizontal reaction tank and a complete mixing tank, those usually used for a polymerization reaction apparatus of a propylene polymer can be used.

<Propylene Polymer Production Method>
Next, the propylene polymer, catalyst, etc. in the present invention will be described in detail.
The method for producing a propylene polymer of the present invention is characterized in that multistage continuous gas phase polymerization of propylene is performed in the presence of an olefin polymerization catalyst using the above-described propylene polymerization reactor. Specifically, the method for producing a propylene-based polymer of the present invention is a continuous multistage production method of propylene, which is obtained by polymerizing propylene (homopolymerization, copolymerization) to produce polypropylene, that is, a polypropylene polymer (propylene homopolymer, propylene). / Α-olefin copolymer). Examples of the α-olefin other than propylene used in the present invention include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, 1-hexene, 1-heptene, 1- For example, octene.
The α-olefin to be used may be changed in each polymerization step, and two or more α-olefins may be used.

In order to provide high productivity of the continuous multistage gas phase polymerization method by the production method of the present invention, it is necessary to use the propylene polymerization reaction apparatus of the present invention described above.
However, in order to obtain a reduction in the amount of non-standard products when changing the residence time in the complete mixing tank, which is a reaction tank that uses the sensible heat of the circulating gas, as described above, the polymerization in the horizontal reaction tank Immediately after that, it is preferable to perform polymerization in a complete mixing tank.

<Olefin polymerization catalyst>
The type of the olefin polymerization catalyst used in the present invention is not particularly limited, and a known catalyst can be used. For example, a so-called Ziegler-Natta catalyst in which a titanium compound and organoaluminum are combined (for example, Japanese Patent Laid-Open Nos. 47-34478, 58-23806, 63-146906, 58-157808, and 58-157808) 58-83006, JP-A-58-5310, JP-A-61-218606) or metallocene catalysts (for example, JP-A-5-295022) can be used. As these catalysts, known catalysts can be used without any particular limitation.

  Moreover, an organoaluminum compound can be used as a promoter. Examples of the organoaluminum compound include trialkylaluminum such as trimethylaluminum, triethylaluminum and triisobutylaluminum, alkylaluminum halide such as diethylaluminum chloride and diisobutylaluminum chloride, alkylaluminum hydride such as diethylaluminum hydride, diethylaluminum ethoxide and the like. Alkyl aluminum alkoxides, alumoxanes such as methylalumoxane and tetrabutylalumoxane, and complex organoaluminum compounds such as dibutyl methylboronate and lithium aluminum tetraethyl. It is also possible to use a mixture of two or more of these.

  In addition, various polymerization additives for the purpose of improving stereoregularity, controlling particle properties, controlling soluble components, controlling molecular weight distribution, and the like can be used in the above-described catalyst. For example, organic silicon compounds such as diphenyldimethoxysilane and tert-butylmethyldimethoxysilane, esters such as ethyl acetate, butyl benzoate, methyl p-toluate and dibutyl phthalate, ketones such as acetone and methyl isobutyl ketone, diethyl ether And electron donating compounds such as ethers such as benzoic acid and propionic acid, and alcohols such as ethanol and butanol.

<Preliminary polymerization treatment>
The catalyst for olefin polymerization in the present invention is preferably preliminarily polymerized before use in the main polymerization. Prior to the main polymerization, a small amount of polymer is generated around the catalyst in advance by pre-polymerization treatment, so that the catalyst becomes more uniform and the generation amount of fine powder can be suppressed.

  The prepolymerization treatment can be carried out in the presence of an organoaluminum compound similar to the organoaluminum compound used for the main polymerization. The amount of the organoaluminum compound to be used varies depending on the type of polymerization catalyst component to be used, but usually the organoaluminum compound is preferably 0.1 to 40 mol, more preferably 0.3 to 1 mol per 1 mol of the titanium atom. It can be used in the range of 20 mol. The temperature during the prepolymerization treatment is preferably −150 ° C. to 150 ° C., more preferably 0 ° C. to 80 ° C. The prepolymerization treatment time is preferably 10 minutes to 48 hours. The prepolymerization treatment amount is preferably 0.1 to 100 grams, more preferably 0.5 to 50 grams of an α-olefin monomer per gram of the olefin polymerization catalyst component. The prepolymerization treatment is usually performed in an inert solvent.

  In the prepolymerization treatment, an electron donor similar to the electron donor used in the main polymerization can be used as necessary. When the electron donor is an organosilicon compound, it may be used in an amount of 0.01 to 10 mol with respect to 1 mol of the organoaluminum compound.

As the monomer used for the prepolymerization treatment of the olefin polymerization catalyst, compounds disclosed in JP-A No. 2004-124090 can be used. Specific examples of the compound include ethylene, propylene, 1-butene, 3-methylbutene-1, 4-methylpentene-1, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, Olefins represented by 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicocene, 4-methyl-1-pentene, 3-methyl-1-pentene, styrene, α-methylstyrene, allylbenzene, chloro Styrene-like compounds typified by styrene and the like, and 1,3-butadiene, isoprene, 1,3-pentadiene, 1,5-hexadiene, 2,6-octadiene, dicyclopentadiene, 1,3-cyclohexadiene, 1 , 9-decadiene, diene compounds typified by divinylbenzene, etc. . Of these, ethylene, propylene, 3-methylbutene-1, 4-methylpentene-1, styrene, divinylbenzenes, and the like are particularly preferable.
These may be used alone or as a mixture of two or more with other α-olefins. In addition, a molecular regulator such as hydrogen can be used in combination in order to regulate the molecular weight of the polymer produced during the polymerization.

  The prepolymerization treatment is generally preferably carried out with stirring, and an inert solvent can also be present at that time. Inert solvents used for pre-polymerization of olefin polymerization catalysts are notable for polymerization reactions such as liquid saturated hydrocarbons such as hexane, heptane, octane, decane, dodecane, and liquid paraffin, and silicon oil having a dimethylpolysiloxane structure. It is an inert solvent that has no effect. These inert solvents may be either one kind of single solvent or two or more kinds of mixed solvents. When these inert solvents are used, it is preferable to use them after removing impurities such as moisture and sulfur compounds which adversely affect the polymerization.

The prepolymerization treatment may be performed a plurality of times, and the monomers used at this time may be the same or different. Further, the olefin polymerization catalyst after the prepolymerization treatment can be washed with an inert solvent such as hexane or heptane. The olefin polymerization catalyst after completion of the prepolymerization treatment can be used as it is, depending on the use form of the catalyst, but may be dried if necessary.
Further, in the prepolymerization treatment, a polymer such as polyethylene, polypropylene and polystyrene or an inorganic oxide solid such as silica and titania may coexist at the time of contacting or after contacting the olefin polymerization catalyst with each of the above components. Is possible.

<Polymerization in horizontal reactor>
In the present invention, propylene is polymerized (homopolymerization, copolymerization) in a horizontal reaction vessel to produce polypropylene, that is, a propylene-based polymer (including propylene homopolymer and propylene / α-olefin copolymer). Examples of the α-olefin other than propylene used in the present invention include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, 1-hexene, 1-heptene, 1- For example, octene.
Polymerization conditions such as temperature and pressure in the horizontal reaction tank can be arbitrarily set as long as productivity is not hindered in order to obtain a desired index (such as MFR and ethylene content). Specifically, the polymerization temperature is preferably 0 ° C. or higher, more preferably 30 ° C. or higher, particularly preferably 40 ° C. or higher, while preferably 100 ° C. or lower, more preferably 90 ° C. or lower, particularly preferably 80 ° C. It is as follows. The polymerization pressure is at least atmospheric pressure, preferably at least 600 kPa, more preferably at least 1000 kPa, particularly preferably at least 1600 kPa. On the other hand, it is preferably at most 4200 kPa, more preferably at most 3500 kPa, particularly preferably at most 3000 kPa. However, the polymerization pressure should not be set higher than the vapor pressure of propylene at the polymerization temperature.
The residence time can be arbitrarily adjusted according to the composition of the polymerization reaction tank and the product index. Generally, it is set within the range of 30 minutes to 10 hours.

<Polymerization in complete mixing tank>
In the present invention, propylene is polymerized (homopolymerization, copolymerization) in a complete mixing tank to produce polypropylene, that is, a propylene-based polymer (including propylene homopolymer and propylene / α-olefin copolymer). Examples of the α-olefin other than propylene used in the present invention include ethylene, 1-butene, 1-pentene, 4-methyl-1-pentene, 5-methyl-1-hexene, 1-hexene, 1-heptene, 1- For example, octene.
In addition, as described above, the “complete mixing tank” in the present invention is preferably a complete mixing reaction tank characterized by removing polymerization heat mainly by sensible heat of the circulating gas. In continuous multistage gas phase polymerization, when production is carried out under polymerization conditions where the dew point of the reaction gas is low, it is difficult to remove heat in the horizontal reaction tank, and the productivity is significantly reduced. Although depending on the balance of the reaction amount of each stage and the ability of the heat exchanger in the continuous multistage polymerization, when the dew point of the reaction gas is less than 50 ° C., the productivity is significantly reduced. As an optimum polymerization reaction tank in a portion where such a polymerization environment is required, a reaction tank that mainly uses sensible heat of the circulating gas is used. The reaction tanks that are widely used include a stirred fluidized bed and a fluidized bed reaction tank. In the present invention, it is more preferable to use a fluidized bed reaction tank in terms of control of residence time and uniform dispersion of the polymer. . The reaction tank uses the sensible heat of the circulating gas to remove the heat of polymerization, and therefore is not affected by productivity due to a decrease in the dew point of the reaction gas. Therefore, in the production method of the present invention, the polymerization reaction in the complete mixing tank is preferably performed using a reaction gas having a dew point of 50 ° C. or less. The “reaction gas” is, as described above, propylene, ethylene-containing α-olefin, hydrogen, and other raw materials.

Polymerization conditions such as temperature and pressure in the complete mixing tank can be arbitrarily set as long as the effects of the present invention are not impaired. For example, in the case of a fluidized bed reactor, specifically, the polymerization temperature is preferably 0 ° C or higher, more preferably 30 ° C or higher, particularly preferably 40 ° C or higher, while preferably 100 ° C or lower, more preferably. 90 ° C. or lower, particularly preferably 80 ° C. or lower. The polymerization pressure is at least atmospheric pressure, preferably at least 600 kPa, more preferably at least 1000 kPa, particularly preferably at least 1600 kPa. On the other hand, it is preferably at most 4200 kPa, more preferably at most 3500 kPa, particularly preferably at most 3000 kPa. However, the polymerization pressure should not be set higher than the vapor pressure of propylene at the polymerization temperature.
The residence time can be arbitrarily adjusted according to the composition of the polymerization reaction tank and the product index. Generally, it is set within the range of 30 minutes to 10 hours.

<Propylene polymer>
In the apparatus and production method of the present invention, as described above, propylene is polymerized (homopolymerization, copolymerization), and polypropylene, that is, a propylene-based polymer (including propylene homopolymer and propylene / α-olefin copolymer). Is manufactured.
The apparatus and the production method of the present invention exhibit the highest effect when producing a polymer having a low molecular weight polypropylene component or a high concentration ethylene component in the polymer component.
For example, when producing homopolypropylene with an expanded molecular weight distribution, a component with a high molecular weight is produced in a horizontal reaction tank, and a component with a low molecular weight is subsequently produced in a complete mixing tank, which is a reaction tank that mainly uses sensible heat of the circulating gas. High productivity can be obtained by manufacturing, and when a fluidized bed reaction vessel is used as a complete mixing vessel, the generation of non-standard products can be minimized when the conditions are changed.
As a specific production example, in the present invention, the intrinsic viscosity of the polymer component produced in the polymerization process using the horizontal reaction vessel for producing the polymer component having the highest molecular weight is 5 to 100 dl / g. The intrinsic viscosity is more than 5 times the intrinsic viscosity of the polymer component produced in the polymerization process using the complete mixing tank for producing the polymer component having the lowest molecular weight, and the polymer component having the highest molecular weight is produced. An example of the propylene-based polymer may be 0.1 to 80% by weight of the polymer component produced in the polymerization process using the horizontal reaction tank.

As another example, a propylene / ethylene copolymer, a propylene / ethylene / 1-butene copolymer, and the like can be suitably produced as copolymers having greatly different ethylene contents in each polymerization step. In particular, it is suitable for production of a propylene-based block copolymer, and examples of the copolymer include propylene-propylene / ethylene block copolymer, propylene / ethylene-propylene / ethylene block copolymer, and the like. Can do.
In the case of a propylene-propylene / ethylene block copolymer, the homopolypropylene component is produced in a horizontal reaction tank, and the propylene / ethylene copolymer component is subsequently added in a complete mixing tank that is a reaction tank that mainly uses sensible heat of the circulating gas. High productivity can be obtained by manufacturing, and when a fluidized bed reaction vessel is used as a complete mixing vessel, the generation of non-standard products can be minimized when the conditions are changed.

As described above, according to the present invention, there is provided an apparatus and a manufacturing method capable of stably producing a continuous multistage polymer at a low cost and with high productivity, and greatly reducing the amount of non-standard products generated by changing the polymerization conditions. can do. Moreover, in this apparatus and a manufacturing method, the substitution property of the polymer in a multistage polymerization reaction apparatus is high, and the product loss accompanying the change of the manufacturing conditions in continuous polymerization is reduced.
Further, the propylene polymer obtained by the apparatus and the production method of the present invention is excellent in the uniformity of the polymer structure between the propylene polymer particles, and is suitably used for automobile parts, home appliance parts, packaging materials and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated in more detail using an Example, this invention is not limited to these Examples. In addition, Example 1 was implemented with the apparatus shown in FIG. The measuring method of each physical property value in the present invention is shown below.

(Various physical property measurement methods)
a) MFR (unit: g / 10 min): Measured at 230 ° C. and 21.18 N according to the method of JIS-K6921.
b) α-olefin content (polymerization ratio in the second stage polymerization step, wt%): measured by an infrared absorption spectrum method.
c) Time required for level change in the second stage polymerization process (hr): The amount of powder held in the reaction vessel is increased from 30 kg to 60 kg while monitoring the fine particles not to be scattered in the circulation system. The time taken was the time required for level change in the second stage polymerization step.

Example 1
1) Preparation of solid catalyst component (olefin polymerization catalyst) A 10 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 2 L of purified toluene was introduced. To this, 200 g of Mg (OEt) ₂ and 1 L of TiCl ₄ were added at room temperature. The temperature was raised to 90 ° C. and 50 ml of n-butyl phthalate was introduced. Thereafter, the temperature was raised to 110 ° C. to carry out a reaction for 3 hours. The reaction product was thoroughly washed with purified toluene. Subsequently, the refined toluene was introduce | transduced and the whole liquid quantity was adjusted to 2L. 1 L of TiCl ₄ was added at room temperature, the temperature was raised to 110 ° C., and the reaction was performed for 2 hours. The reaction product was thoroughly washed with purified toluene. Further, using purified n-heptane, toluene was replaced with n-heptane to obtain a slurry of a solid catalyst component. A portion of this slurry was sampled and dried. As a result of analysis, the Ti content of the solid catalyst component was 2.7 wt%, and the Mg content was 18 wt%. The average particle size of the solid catalyst component was 33 μm.

2) Prepolymerization treatment of solid catalyst component After replacing a stainless steel reaction vessel with an inclined blade having an internal volume of 20 liters with nitrogen gas, 17.7 liters of hexane, 100.6 mmol of triethylaluminum, 15.1 mmol of diisopropyldimethoxysilane, After adding 120.4 g of the adjusted solid catalyst component at room temperature, the mixture was heated to 30 ° C. Next, 240.8 g of propylene was supplied over 3 hours with stirring, and a preactivation treatment was performed. As a result of analysis, 1.9 g of propylene was reacted per 1 g of the solid catalyst.

3) First-stage polymerization step This will be described with reference to the flow sheet shown in FIG. 0.95 g / hr of the solid catalyst subjected to the above preactivation treatment (preliminary polymerization treatment) in a horizontal polymerization vessel (L / D = 5.2, internal volume 100 liters) having a stirring blade, triethylaluminum and organic as organic aluminum compounds Diisopropyldimethoxysilane was continuously supplied as a silicon compound at 42 mmol / h and 7.0 mmol / h so that the Al / Mg molar ratio was 6 and the Al / Si molar ratio was 6, respectively. While maintaining the conditions of a reaction temperature of 65 ° C., a reaction pressure of 2.2 MPa, and a stirring speed of 35 rpm, hydrogen gas was added so as to maintain the hydrogen concentration in the gas phase in the polymerization vessel at a hydrogen / propylene molar ratio of 0.002. The MFR of the first stage polymer was adjusted by continuously supplying from the circulation pipe 2.

The reaction heat was removed by the heat of vaporization of the raw material liquefied propylene supplied from the pipe 3. The unreacted gas discharged from the polymerization vessel was cooled and condensed outside the reaction tank system through the pipe 4 and refluxed to the polymerization vessel 10 through the pipe 2.
The produced first-stage polymerization polymer is intermittently withdrawn from the polymerization vessel 10 through the pipe 11 so that the polymer retention level is 60% by volume of the reaction volume, and is supplied to the polymerization vessel 20 in the second-stage polymerization step. did. A part of the polymer was taken out, and used as a sample for measuring MFR and measuring the polymer yield per unit weight of the catalyst. The MFR was 0.8 g / 10 min. The polymer yield per catalyst unit weight was calculated from the Mg content in the polymer measured by inductively coupled plasma emission spectrometry (ICP method). The Mg content was 13.1 ppm.

4) Second-stage polymerization step Following the first-stage polymerization step, polymerization in the second-stage polymerization step was carried out in a fluidized bed reactor having an internal volume of 2000 liters. At a reaction temperature of 70 ° C., hydrogen as a molecular weight control agent was continuously supplied so that the molar ratio of hydrogen / propylene was 0.13 so that the pressure was 2.0 MPa. The dew point of the reaction gas was 46 ° C.
The powder polymerized in the second reaction tank is made to flow so that the superficial velocity becomes 0.40 m / sec, and about 2 kg at a time so that the average amount of powder in the reaction tank is 30 kg. Intermittently extracted into a vessel once every 5 to 10 minutes and transferred to another vessel, where nitrogen gas containing moisture is supplied to stop the reaction, purge the remaining propylene, Obtained. The production rate of the propylene polymer was 21 kg on average per hour. Further, in the second stage polymerization step, the amount of powder held in the reaction vessel was increased from 30 kg to 60 kg while monitoring the fine powder particles not to be scattered in the circulation system, and the time required at this time was measured. It took time.

  A part of the obtained polymer was used as a sample for measuring MFR and measuring the polymer yield per unit weight of the catalyst. The MFR was 4.9 g / 10 minutes. The polymer yield per unit catalyst weight was calculated by dividing the production rate by the solid catalyst feed rate. The results are shown in Table 1.

(Comparative Example 1)
Polymerization was carried out using a continuous reaction apparatus in which two horizontal polymerization reactors (L / D = 5.2, internal volume 100 liters) having stirring blades were connected.
First, 0.59 g / hr of the solid catalyst subjected to the preactivation treatment (preliminary polymerization treatment) described in Example 1 in the first reaction tank, triethylaluminum as the organoaluminum compound, diisopropyldimethoxysilane as the organosilicon compound, Al / They were continuously fed at 26 mmol / h and 4.4 mmol / h, respectively, so that the Mg molar ratio was 6 and the Al / Si molar ratio was 6. While maintaining the conditions of a reaction temperature of 65 ° C., a reaction pressure of 2.2 MPa, and a stirring speed of 35 rpm, hydrogen gas was added so as to maintain the hydrogen concentration in the gas phase in the polymerization vessel at a hydrogen / propylene molar ratio of 0.002. Continuously fed, the MFR of the first stage polymer was adjusted. The MFR was 0.7 g / 10 minutes. The produced first-stage polymerization polymer was intermittently withdrawn so that the retained level of the polymer was 60% by volume of the reaction volume, and was supplied to the polymerization vessel of the second-stage polymerization process (first-stage polymerization process). .
While maintaining the conditions of a polymerization temperature of 70 ° C., a pressure of 2.0 MPa, and a stirring speed of 35 rpm, hydrogen as a molecular weight control agent was continuously supplied so that the molar ratio of hydrogen / propylene was 0.13. The dew point of the reaction gas was 46 ° C.
The powder polymerized in the second reaction tank is withdrawn intermittently so that the retained level of the polymer is 60% by volume of the reaction volume, the nitrogen gas containing moisture is supplied to stop the reaction, and the propylene polymer is Obtained (second stage polymerization step).
The production rate of the propylene polymer was 14.8 kg / hr. The MFR was 3.7 g / 10 minutes. In order to increase the production rate of the propylene polymer, an attempt was made to increase the supply amount of the solid catalyst, but the load on the heat exchanger in the second stage polymerization process became large, and it was difficult to maintain the pressure. The results are shown in Table 1.

(Comparative Example 2)
1) Preparation of solid catalyst component A solid catalyst component was prepared according to Example 1.
2) Prepolymerization treatment of solid catalyst component A 20 L autoclave equipped with a stirrer was sufficiently substituted with nitrogen, and 100 g of the solid catalyst component was introduced. 50 ml of silicon tetrachloride was added and the reaction was carried out at 90 ° C. for 1 hr, and then the reaction product was thoroughly washed with purified n-heptane. After the purified n-heptane was introduced to adjust the liquid level to 4 L, 30 ml of dimethyldivinylsilane, 30 ml of diisopropyldimethoxysilane, and 80 g of triethylaluminum were added, and a reaction was performed at 40 ° C. for 2 hours. The reaction product was thoroughly washed with purified n-heptane. Again, purified n-heptane was introduced to adjust the concentration of the solid catalyst component to 20 g / L. After the slurry was cooled to 10 ° C., 10 g of triethylaluminum was added, and 280 g of propylene was supplied over 4 hours. After the supply of propylene was completed, the reaction was further continued for 30 minutes. Next, the gas phase was sufficiently replaced with nitrogen, and the reaction product was thoroughly washed with purified n-heptane. The obtained slurry was extracted from the autoclave and vacuum-dried to obtain a preactivated solid catalyst. As a result of analysis, 2.5 g of polypropylene was contained per 1 g of the solid catalyst.

3) Polymerization Polymerization was performed using a continuous reaction apparatus in which two fluidized bed reactors having an internal volume of 2000 liters were connected. In the first reaction tank, 1.01 g / hr of the solid catalyst subjected to the preactivation treatment (preliminary polymerization treatment), and triethylaluminum as the organic aluminum compound were continuously added at 45 mmol / h so that the Al / Mg molar ratio was 6. Supplied. A reaction temperature of 65 ° C., a propylene partial pressure of 2.0 MPa, and hydrogen as a molecular weight controlling agent were continuously supplied so that the molar ratio of hydrogen / propylene was 0.002. The MFR was 0.8 g / 10 min.
The powder polymerized in the first reaction tank is made to flow so that the superficial velocity becomes 0.35 m / sec, and about 2 kg at a time so that the average amount of powder in the reaction tank is 30 kg. After intermittently extracting to the vessel once every 5 to 10 minutes, it was further transferred to the second reaction tank (first stage polymerization step).
In the second reaction tank, propylene and hydrogen as a molecular weight control agent were continuously supplied at a polymerization temperature of 70 ° C. and a pressure of 2.0 MPa so that the hydrogen / propylene molar ratio was 0.13. . The dew point of the reaction gas was 46 ° C.
The powder polymerized in the second reaction tank is made to flow so that the superficial velocity becomes 0.40 m / sec, and about 2 kg at a time so that the average amount of powder in the reaction tank is 30 kg. Intermittently extracted into a vessel once every 5 to 10 minutes and then transferred to another vessel where nitrogen gas containing moisture was supplied to stop the reaction, purge the remaining propylene, A coalescence was obtained (second stage polymerization step).
The production rate of the propylene polymer was 20 kg on an average per hour. The MFR was 6.4 g / 10 minutes. Further, in the second stage polymerization step, the amount of powder held in the reaction vessel was increased from 30 kg to 60 kg while monitoring the fine powder particles not to be scattered in the circulation system, and the time required at this time was measured. It cost. The results are shown in Table 1.

As is apparent from Table 1, the propylene polymerization reaction apparatus and the propylene polymer production method of the present invention are “a horizontal reaction tank having a stirrer rotating around a horizontal axis therein, and a connection to the horizontal reaction tank. In Comparative Examples 1 and 2, which are methods that do not satisfy the requirement that at least one complete mixing tank is provided, the production rate is significantly reduced under conditions where the dew point of the reaction gas is less than 50 ° C. (Comparative Example 1) Or, it takes a lot of time to change the polymerization conditions (Comparative Example 2).
Therefore, according to Example 1, in the method for producing a propylene multi-stage continuous gas phase polymer containing a polymerization component requiring a low dew point reaction gas condition, a horizontal reaction tank and a complete mixing tank, which are specific matters of the present invention, are combined. In addition to maintaining high productivity by using the propylene polymerization reactor, it is excellent in that it is extremely easy to adjust (short time) when changing the polymerization conditions (residence time). It was confirmed that a result was obtained.

  In the apparatus and the production method of the present invention, a continuous multistage polymer of a propylene-based polymer can be produced with a minimum equipment investment cost and stably maintaining high productivity. In the legal method, when the residence time is changed in a specific gas phase polymerization reactor, the adjustment becomes extremely easy (short time), and as a result, the amount of non-standard products generated by changing the polymerization conditions is greatly reduced. Since it can be manufactured, it is very useful industrially.

Claims (9)

  A reaction apparatus for producing a propylene-based polymer by a multistage continuous gas phase polymerization method, a horizontal reaction tank having a stirrer rotating around a horizontal axis therein, and a complete mixing tank connected to the horizontal reaction tank; Are each provided with at least one tank or more.   The propylene polymerization reaction apparatus according to claim 1, wherein the complete mixing tank is a reaction tank that mainly removes the heat of polymerization using sensible heat of the circulating gas.   The propylene polymerization reactor according to claim 1 or 2, wherein the complete mixing tank is a reaction tank selected from a vertical stirring tank, a stirring fluidized bed reaction tank, or a fluidized bed reaction tank.   The propylene polymerization reactor according to claim 1 or 2, wherein the complete mixing tank is a fluidized bed reaction tank.   5. The propylene polymerization reactor according to claim 1, wherein the horizontal reaction tank has an L / D of 5 or more (L: length in the horizontal longitudinal direction, D: inner diameter). .   The propylene polymerization reactor according to any one of claims 1 to 5, wherein the complete mixing tank is provided immediately after the horizontal reaction tank.   A method for producing a propylene-based polymer, comprising performing multistage continuous gas phase polymerization of propylene in the presence of an olefin polymerization catalyst using the propylene polymerization reactor according to any one of claims 1 to 6. .   The method for producing a propylene-based polymer according to claim 7, wherein the polymerization reaction in the complete mixing tank is performed using a reaction gas having a dew point of 50 ° C or lower. The propylene-based polymer according to claim 7 or 8, wherein a polymerization reaction of propylene is performed in the horizontal reaction tank, and then a polymerization reaction of propylene and an α-olefin containing ethylene is performed in the complete mixing tank. Manufacturing method.

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