JP4843188B2 - Polyolefin production method and gas phase polymerization apparatus - Google Patents

Description

  The present invention relates to a method for producing a polyolefin, particularly a polyolefin such as a propylene block copolymer, and more specifically, by gas phase polymerization using an olefin polymerization catalyst, the adhesion of the polymer to the polymerization tank and the polymerization stirring blade is suppressed, The present invention relates to a production method and a gas phase polymerization apparatus capable of producing a polyolefin for a long time, continuously and stably.

  Polyolefins, such as polypropylene and propylene block copolymers, dramatically increase the polymer production per catalyst and improve the regularity by improving the Ziegler / Natta catalyst and increasing the activity and stereoregularity. Has been achieved. As a result, metal components such as transition metal catalyst components present in the polymer can be reduced, and amorphous polypropylene components can be reduced. For this reason, compared to conventional solution polymerization, slurry polymerization, bulk polymerization, etc., there is no need for solvent recovery and purification steps, easy monomer recovery and polymer drying, and diversification of products. Therefore, the polymerization method by the gas phase method has been attracting attention.

  For example, in the presence of a highly stereoregular olefin polymerization catalyst, a crystalline homopolymer or copolymer of propylene is produced in a pre-stage polymerization tank, and rubber of propylene and other α-olefin such as ethylene is produced in the post-stage polymerization tank. Propylene block copolymer is produced to produce a random copolymer. This propylene block copolymer is a composition having excellent strength, rigidity and heat resistance of crystalline polypropylene, as well as impact resistance by the rubber-like random copolymer, particularly impact resistance at low temperature. For this reason, it has been widely used as automobile parts such as exterior materials such as bumpers, interior materials such as instrument panels and doors, containers, and seats.

  Thus, the polyolefin production method by the vapor phase method is a very excellent process. However, in the gas phase method, the gas phase polymerization tank is divided into a powder part and a gas phase part of the polymer regardless of the gas phase fluidized bed type and the stirred fluidized bed type, and thus the entire tank. As compared with the solution method or the slurry method, the stirring effect and the homogenizing effect may not be sufficient. In particular, in the second random copolymer polymerization tank in the production of the propylene block copolymer, since the copolymer is rubbery and has high adhesiveness, the adhesion between the polymer and the copolymer particles, There is a problem that adhesion to the walls of the polymerization tank and the stirring blade is likely to occur.

  This adhesion not only makes it difficult to achieve a stable and long-term continuous production, but also causes such problems that the adhesion causes high molecular weight and gelation, resulting in deterioration of the quality of the final molded product. In addition, a small lump produced by the adhesion of particles may cause troubles such as clogging of the polymer powder transfer pipe. Further, there may be a case where the filter is clogged in the monomer circulation pipe for cooling. Here, the deterioration of quality means insoluble or hardly meltable components due to gelation due to long-term retention due to adhesion, resulting in deterioration of physical properties and deterioration of commercial value, such as deterioration of appearance of molded products and starting point of destruction. That is.

  For this reason, a method of adding an alkoxyaluminum compound has been disclosed for the purpose of preventing adhesion of polymer particles in the production of polyolefins, particularly propylene block copolymers (see Patent Documents 1 and 2). If the amount of the alkoxyaluminum compound added is not large, the effect is not obtained, and there is a problem that application to the gas phase method becomes difficult due to an increase in the aluminum content in the polymer.

  Moreover, the manufacturing method which supplies an active hydrogen compound to the random copolymerization reaction system in the ratio of 0.001-1 mol per 1g atom of aluminum of a highly stereoregular polymerization catalyst is disclosed (refer patent document 3). However, this publication only shows an example of batch polymerization rather than continuous polymerization. Therefore, it is shown that the specific supply method of the active hydrogen compound and the bulk density of the obtained polymer are increased, but the adhesion preventing effect is not particularly shown. This is considered a natural result from the uniformity by batch polymerization.

Further, in the gas phase polymerization reaction system, a method for supplying alcohols to a cooling monomer circulation system, a transfer flow path between a crystalline polypropylene polymerization tank and a propylene random copolymer polymerization tank is specifically shown. (See Patent Document 4, Patent Document 5, Patent Document 6, and Patent Document 7). In any case, these methods are methods in which the olefin polymerization catalyst activity inhibitor is not directly supplied to the polymerization tank. These methods are intended to improve the dispersibility by supplying the catalyst activity inhibitor into the polymer powder transfer or the monomer supply pipe, but as a result, the catalyst activity inhibitor is added to the polymerization tank. It can be said that it is an excellent method.

  Further, Patent Document 7 shows an example in which a heptane solution of 17% by mass of isopropanol is weighed and fed into a transfer conduit connecting the first and second reactors of two reactors. Yes. As a comparative example, a method of measuring and feeding the same solution directly to a subsequent reactor is shown. As a result, in the case of the example in operation for 3 weeks, the amount of agglomerates and aggregates in the powder bed of the latter reactor was 45 to 35% in comparison with the comparative example, the wall of the reactor, the obstacle It is shown that the amount of film and deposit on the plate surface was reduced to 25 to 35%, respectively. However, although the reduction effect has been quantitatively evaluated, it is clear that there is a limit to the reduction of agglomerates, aggregates, and deposits even with an improved method, which is not always satisfactory.

  Further, in the method for producing polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, the catalyst activity inhibitor is supplied from the gas phase part of the polymerization tank and from the side wall of the polymerization tank to the powder part of the polymerization tank. (Patent Document 8). Even in this method, there is a limit in preventing the deposits on the upper part of the stirring blade. Therefore, depending on the type of the polymerization tank and the polymerization conditions, there are considerable lumps and aggregates. There is still room for improvement in terms of problems.

JP-A-56-151713 JP-A-58-213012 JP-A-61-69821 JP-A-63-225613 JP-A-4-296313 JP-A-4-296314 Japanese Patent Laid-Open No. 11-71415 JP 2001-261720 A

  The present invention has been made under such circumstances. In a method for producing polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, a lump or agglomerate is formed, or a polymer on a polymerization tank wall or a stirring blade is produced. It is an object of the present invention to provide a polyolefin production method and a gas phase polymerization apparatus that suppresses the adhesion of the resin, does not clog piping, can be stably continuously produced, and does not deteriorate in quality.

As a result of intensive studies, the present inventors supply a cooling liquid circulating medium from at least one of the bottom surface and the side surface of the polymerization tank in a method for producing polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst. Thus, the inventors have found that the above object can be achieved and completed the present invention. That is, the present invention
(1) A method for producing a polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, wherein in the polymerization having a plurality of polymerization stages, propylene is used in the presence of a stereoregular catalyst in the first polymerization tank. After producing crystalline polypropylene which is a copolymer of propylene having a coalescence or other α-olefin content of 5% by mass or less, in the second polymerization tank, propylene and other α in the presence of the crystalline polypropylene. -When producing a propylene block copolymer by random copolymerization with an olefin, a monomer is supplied from a monomer supply pipe provided in a gas phase part at the upper part of the second polymerization tank, and a cooling liquid circulation medium is obtained . Supply to the second polymerization tank from the bottom and at least one side of the second polymerization tank having the stirring blades, with respect to the supply amount of the cooling liquid circulation medium from the bottom The supply amount of the cooling liquid circulation medium from the side surface of the second polymerization tank is 0.05 to 0.5 times the mass, and the cooling liquid circulation medium is supplied to the powder part of the second polymerization tank. A process for producing a polyolefin characterized by
(2) The method for producing a polyolefin according to (1), wherein the cooling liquid circulation medium is supplied from a height of 1/2 or more of the height of the powder part of the second polymerization tank having a stirring blade,
(3) An olefin polymerization catalyst is obtained using a solid catalyst component obtained by using (A) (a) a magnesium compound and (b) a titanium compound, (B) an organoaluminum compound and (C) an electron donating compound. The method for producing a polyolefin according to the above (1) or (2), which is a highly stereoregular catalyst to be produced ,
( 4 ) The polyolefin according to any one of (1) to (3) above, wherein the amount of the random copolymer produced in the second polymerization tank is 5 to 50% by mass with respect to the propylene block copolymer. Manufacturing method,
( 5 ) Said (1)-(4) whose copolymerization ratio (mass ratio) of propylene and another alpha olefin in the random copolymer manufactured by a 2nd polymerization tank is 20-85 / 80-15. A process for producing the polyolefin according to any one of
Is to provide.

  According to the present invention, in a method for producing a polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, without adding a third component, and without providing a mechanical adhesion prevention facility, a polymerization tank wall and stirring It is possible to prevent the polymer from adhering to the wing, and it is possible to produce a polyolefin without quality deterioration.

  The present invention can be generally applied to a method for producing a polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, and is particularly preferably applicable to a method for producing a propylene block copolymer. The monomer used for the production of the polyolefin of the present invention is not particularly limited, and ethylene, propylene, 1-butene, 1-pentene, 4-methyl-pentene-1, 1-hexene, 1-octene, 1-nonene, An α-olefin such as 1-decene can be exemplified. These α-olefins can be homopolymerized, or can be copolymerized with two or more α-olefins or copolymers with other copolymerizable monomers such as vinyl acetate and acrylic acid. it can.

  There is no restriction | limiting in particular as an olefin polymerization catalyst used for the manufacturing method of polyolefin of this invention, Various well-known catalysts are used. These catalysts include, for example, Ziegler / Natta based catalysts containing a solid catalyst component prepared using a halide or alcoholate of trivalent or tetravalent titanium, an alkoxytitanium halide and magnesium chloride, alkoxymagnesium, etc. Examples of the olefin polymerization catalyst used in a known gas phase method such as a supported solid catalyst using a metallocene-based compound including a titanium, zirconium, or hafnium-based compound having a pentadienyl group as a catalyst component can be given. Examples of these catalyst components include organoaluminum compounds such as alkylaluminum and aluminoxane, ionic complexes, catalysts prepared using an electron donor, etc., and known catalysts such as Lewis acids. . Furthermore, an electron donating compound can be used during the polymerization.

  There is no restriction | limiting in particular as a gas phase polymerization tank used for manufacture of the gas phase method polyolefin of this invention, Various well-known apparatuses can be used. For example, Chemical Equipment, pages 62-74, Vol. 41 (1999). Specifically, a fluidized bed type polymerization tank (for example, JP-A-4-234409) and a vertical polymerization tank having a stirring blade (JP-A-53-123487, JP-A-54-23258). Etc.), a horizontal polymerization tank having a stirring blade (Japanese Patent Laid-Open No. 63-22001, etc.), and the like.

  Moreover, as a superposition | polymerization tank, you may have a single stage or a single superposition | polymerization tank, and several superposition | polymerization tanks of two or more steps. In these gas phase process polymerization tanks, a solid catalyst and a monomer are usually continuously supplied to the polymerization tank, and polymerized polymer particles are continuously or intermittently extracted. Further, a method is adopted in which the monomer gas in the polymerization tank is cooled by an external compressor and condenser, the cooled monomer is sprayed onto the polymerization tank, and the heat of polymerization is removed by the latent heat of evaporation.

  Especially, the manufacturing method of the polyolefin of this invention is preferably applicable to manufacture of the polyolefin using two or more polymerization tanks, normally two polymerization tanks. That is, polymerization is carried out to obtain polymers (copolymers) having different properties in the preceding polymerization tank and the subsequent polymerization tank. For example, the latter polymerization tank can be suitably used when rubber-like random copolymerization is carried out in the presence of the crystalline polyolefin polymerized in the former stage, and as a result, a polyolefin as a mixed composition of both polyolefins is produced.

  Examples of such two-stage polymerization include polymerization of polyolefins having different molecular weights in each polymerization tank, (co) polymerization with different monomers, copolymerization with different copolymerization compositions, (co) polymerization with different crystallinity, and combinations thereof A production method corresponding to the target polyolefin can be selected.

The polyolefin production method of the present invention is characterized in that, in the production method of polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, a cooling circulation medium is supplied from the bottom surface and at least one side surface of the polymerization tank. Thus, it can be mainly applied to the polymerization tank in the latter stage of the two-stage polymerization. The cooling circulation medium only needs to remove the heat of polymerization, and liquid, gas, or a mixture of liquid and gas can be used. In particular, liquid is preferable because of its excellent cooling effect.
Next, the polyolefin gas phase polymerization apparatus of the present invention is a polyolefin gas phase polymerization apparatus having a monomer supply pipe, a polymer discharge pipe, and a polymerization tank optionally equipped with a stirring blade. The cooling circulation medium supply mechanism for supplying the cooling circulation medium is provided. The apparatus of the present invention will be described by taking a method for producing a propylene-ethylene block copolymer as an example. FIG. 1 is a schematic view showing an embodiment of a subsequent polymerization tank in a propylene-ethylene block copolymer production apparatus which is an example of a polyolefin gas phase polymerization apparatus of the present invention. The latter polymerization tank 1 is composed of a monomer supply pipe 2, a polymer discharge pipe 3, a cooling circulation medium supply mechanism 4, and optionally a stirring blade 5. The polymerization tank includes a gas phase part (upper part) 6 and a powder part ( (Bottom) Divided into 7. The cooling circulation medium is usually 0.01 to 1% by mass of hydrogen, 5 to 40% by mass of ethylene, 40 to 90% by mass of propylene, 4 to 20% by mass of propane, and 0 to 1% by mass of nitrogen. , Methane consists of 0.01-5 mass%. In the present invention, it is important to supply the cooling circulation medium not only from the bottom but also from the side to the powder part of the polymerization tank. It is preferable to supply. The supply from this side surface varies depending on the structure of the polymerization tank, the formation state of the powder part, etc., but may be supplied from a plurality of positions. Moreover, about the amount, the supply amount from the side surface is usually 0.05 to 0.5 times (mass) with respect to the supply amount from the bottom surface. Note that the cooling circulation medium supply mechanism generally employs a nozzle.

  The method for producing a polyolefin of the present invention is a propylene copolymer having a content of 5% by mass or less of propylene homopolymer or other α-olefin in the first polymerization tank, particularly in polymerization having a plurality of polymerization stages. In producing a propylene block copolymer by randomly copolymerizing propylene and another α-olefin in the presence of the crystalline polypropylene in the second polymerization tank after producing the crystalline polypropylene, It can be preferably applied to a method for producing block polypropylene in which the supply of the circulating medium for cooling in the second polymerization tank is supplied not only from the bottom but also from the position of the side wall of the polymerization tank.

  An example of the polyolefin production method and polymerization apparatus of the present invention is the production of a propylene block copolymer. Here, the propylene block copolymer is a homopolymer of propylene or other α of propylene and 5% by mass or less of ethylene, 1-butene and the like in the presence of a stereoregular catalyst in the gas phase polymerization tank in the previous stage. -Polymerizing a crystalline polypropylene resin that is a copolymer with olefin, continuously transferring the crystalline polypropylene resin to a subsequent polymerization tank, and propylene and other α-olefins such as ethylene in the subsequent polymerization tank And rubbery random copolymerization. Thus, a propylene block copolymer having excellent impact resistance, particularly low temperature impact resistance, can be produced by a continuous phase composed of crystalline polypropylene and a dispersed phase composed of rubber-like particles (including polyethylene). Here, the block polypropylene copolymer which has the characteristic according to the objective can be manufactured by control of the copolymerization composition of random copolymer, control of molecular weight, control of content, etc. Here, in the random copolymer in the latter stage polymerization tank, the monomer is a combination of propylene and another α-olefin such as ethylene and 1-butene, but the copolymerization ratio of propylene and another α-olefin ( Mass) is usually 10 to 90/90 to 10, preferably 20 to 85/80 to 15. Moreover, the content rate of the random copolymer copolymerized in the latter stage in a propylene block copolymer is 3-60 mass% normally, Preferably it is 5-50 mass%.

An example of the polymerization catalyst includes a highly stereoregular catalyst obtained by using (A) a solid catalyst component containing at least a magnesium atom, a titanium atom and a halogen atom, and (B) an organoaluminum compound. As such a catalyst, the highly stereoregular catalyst obtained, for example using the following (A) component and (B) component is mentioned. (A) Solid catalyst component (B) Organoaluminum compound obtained by using (a) magnesium compound and (b) titanium compound Also preferably, the following (A) component, (B) component and (C) component are used And a highly stereoregular catalyst obtained in the above manner.
(A) Solid catalyst component obtained by using (a) magnesium compound and (b) titanium compound (B) Organoaluminum compound (C) Electron donating compound

Here, the following compounds can be used as the compound.
(A) Magnesium compound The magnesium compound is not particularly limited, and includes magnesium oxide, magnesium hydroxide, dialkylmagnesium, alkylmagnesium halide, magnesium halide, magnesium dialkoxide, specifically magnesium chloride, magnesium diethoxide, A magnesium dimethoxide etc. can be mentioned. Moreover, as a magnesium compound, the well-known solid product obtained by making metal magnesium, a halogen, and alcohol react can be used conveniently. Here, examples of the alcohol include methanol and ethanol, and those having a water content of 200 ppm or less are easy to obtain a solid product having a good morphology. As halogen, chlorine, bromine, iodine, particularly iodine is preferably used.

(B) Titanium Compound As the titanium compound, any titanium compound can be used. For example, the general formula (1)
TiX ¹ _n (OR ¹ ) _4-n ... (1)
(Wherein X ¹ is a halogen atom, particularly a chlorine atom, R ¹ is a hydrocarbon group having 1 to 10 carbon atoms, particularly a linear or branched alkyl group, and a plurality of groups R ¹ are present. May be the same or different from each other, and n is an integer of 0 to 4.). Specifically, Ti (O-i-C 3 H 7) 4, Ti (O-C 4 H 9) 4, TiCl (O-C 2 H 5) 3, TiCl (O-i-C 3 H 7 ) ₃ , TiCl (O—C ₄ H ₉ ) ₃ , TiCl ₂ (O—C ₄ H ₉ ) ₂ , TiCl ₂ ( _{O-i-C 3 H 7} ) can be exemplified _2, TiCl ₄ or the like.

(C) Electron-donating compound As the solid catalyst component (A), any electron-donating compound (c) can be used as necessary. These electron donating compounds are usually organic compounds containing oxygen, nitrogen, phosphorus or sulfur. Specifically, amines, amides, ketones, nitriles, phosphines, esters, ethers, thioethers, alcohols, thioesters, acid anhydrides, acid halides, aldehydes, organic acids, An organosilicon compound having a Si—O—C bond can be given.

  Specifically, for example, aromatic phthalic acid diesters such as diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, dihexyl phthalate, dimethyldimethoxysilane, diethyldiethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, di- Preferred examples include organosilicon compounds such as t-butyldimethoxysilane, diisobutyldimethoxysilane, diisopropyldimethoxysilane, dicyclohexyldimethoxysilane, and dicyclopentyldimethoxysilane.

Preparation method of solid catalyst component (A) The solid catalyst component (A) is prepared by a known method using a magnesium compound (a), a titanium compound (b), and, if necessary, an electron donating compound (c). it can. For example, the magnesium compound (a) and the electron donating compound (c) are contacted and then contacted with the titanium compound (b). The contact conditions are not particularly limited, and usually 0.01 to 10 mol, preferably 0.05 to 5 mol of an electron donating compound (c) is added to 1 mol of the magnesium compound (a) in terms of magnesium atom, Contact is performed at 0 to 200 ° C. for 5 minutes to 10 hours, preferably at 30 to 150 ° C. for 30 minutes to 3 hours. In addition, inert hydrocarbons such as pentane, hexane, and heptane can be added to this preparation.

  The conditions for contacting the titanium compound (b) with the magnesium compound (a) or the contact product of the electron donor compound (c) with the magnesium compound (a) are not particularly limited. The titanium compound (b) is added in an amount of 1 to 50 mol, preferably 2 to 20 mol, and contacted at 0 to 200 ° C. for 5 minutes to 10 hours, preferably at 30 to 150 ° C. for 30 minutes to 5 hours. The contact with the titanium compound (b) can be performed in a state where the liquid titanium compound (for example, titanium tetrachloride) is used alone and the other titanium compounds are dissolved in an arbitrary inert hydrocarbon. Further, before the contact between the magnesium compound (a) and, if necessary, the electron donating compound (c), for example, halogenated hydrocarbon, halogen-containing silicon compound, halogen gas, hydrogen chloride, hydrogen iodide Etc. can be brought into contact with the magnesium compound (a). In addition, after completion | finish of contact, it is preferable to wash | clean a product with an inert hydrocarbon.

(B) Organoaluminum compound The organoaluminum compound (B) is not particularly limited, and the following general formula (2)
AlR ² _m X ² _3-m (2)
Wherein R ² is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group or an aryl group, m is an integer of 1 to 3, and X ² is represented by a halogen atom (chlorine or bromine atom). Specific examples include trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, triisopropylaluminum and triisobutylaluminum, and dialkylaluminum monochlorides such as diethylaluminum monochloride and dipropylaluminum monochloride. Can do.

(C) Electron-donating compound In the manufacturing method of block polypropylene, an electron-donating compound (C) can be used together as needed. As the electron donating compound (C) in this case, the same electron donating compound (c) used in the preparation of the solid catalyst component (A) can be used. In this case, it may be the same as or different from that used in the preparation of the solid catalyst component. A preferred electron donating compound (C) is a silane compound having a SiO—C bond, particularly a compound represented by the following formula (3).
R ³ _p Si (OR ⁴ ) _4-p (3)
(Wherein, R ³ is a linear or branched hydrocarbon group, aromatic hydrocarbon group or a cyclic saturated hydrocarbon group, for p ≧ 2, or a combination of any of .R ⁴ of the compound Is a linear hydrocarbon group or a branched hydrocarbon group, and p is an integer of 0 to 3.) Specific examples of the compound of the formula (3) include t-butylcyclohexyldimethoxysilane, methylcyclohexyldimethoxysilane, di-t-butyldimethoxysilane, dicyclohexyldimethoxysilane, diphenyldimethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, Examples thereof include methylphenyldimethoxysilane.

Further, a catalyst activity inhibitor may be used to stabilize the polymerization in the polymerization tank. Specifically, it can be selected from alcohols, phenols, carboxylic acids, sulfonic acids, amines, amides, esters, ethers, phosphines, water, carbon monoxide and carbon dioxide. Preferred examples of the catalyst activity inhibitor include compounds containing active hydrogen. Active hydrogen-containing compounds include alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, t-butanol and n-hexanol, phenols such as phenol, cresol and xylenol, formic acid, acetic acid, propionic acid, Examples thereof include carboxylic acids such as benzoic acid, sulfonic acids such as sulfonic acid, benzenesulfonic acid and toluenesulfonic acid, amines such as ethylamine and isopropylamine, and water. Among these active hydrogen-containing compounds, examples thereof include methanol, ethanol, n-propanol, and isopropanol, which are linear or branched alcohols having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms. A plurality of these catalyst activity inhibitors can be used.
These catalyst activity inhibitors can be used alone, or can be supplied together with a carrier fluid such as an inert hydrocarbon solvent such as monomer or heptane, hydrogen or nitrogen.

  Regarding the reaction conditions, the polymerization temperature is 40 to 100 ° C., preferably 50 to 90 ° C., the polymerization pressure is about 0.1 to 10 MPa, and the intrinsic viscosity [η] measured in 135 ° C. tetralin is 1 to 10 dl / g, preferably The molecular weight is adjusted using hydrogen or the like so as to be about 1 to 6 dl / g.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not restrict | limited at all by these examples.

Example 1 Production of Propylene-Ethylene Block Copolymer (1) Production of Magnesium Compound (a) A glass reactor equipped with a stirrer (internal volume of about 12 liters) was sufficiently replaced with nitrogen gas, and ethanol of about 4,860 g. Then, 32 g of iodine and 320 g of metallic magnesium were added, and the reaction was carried out under heating under stirring under reflux conditions until no hydrogen gas was generated from the system to obtain a solid reaction product. The solid reaction product was dried under reduced pressure to obtain a magnesium compound [solid product] (a).
(2) Preparation of solid catalyst component (A) In a glass three-necked flask (with an internal volume of 5 liters) sufficiently substituted with nitrogen gas, 160 g of the unpulverized magnesium compound (a), 800 ml of purified heptane, silicon tetrachloride 24 Milliliter and 23 ml of diethyl phthalate were added. The system was kept at 90 ° C., and 770 ml of titanium tetrachloride was added while stirring and reacted at 110 ° C. for 2 hours. Then, the solid components were separated and washed with purified heptane at 80 ° C. Further, 1220 ml of titanium tetrachloride was added and reacted at 110 ° C. for 2 hours, and then sufficiently washed with purified heptane to obtain a solid catalyst component (A).

(3) Pre-polymerization treatment Into a reaction vessel equipped with a stirring blade having an internal volume of 500 liters, 230 liters of n-heptane was charged and 25 kg of the solid catalyst component (A) and triethylaluminum were added to Ti atoms in the solid catalyst component (A). In contrast, after supplying 0.6 mol / 1 g atom and diphenyldimethoxysilane at a ratio of 0.4 mol / 1 g atom to Ti atom in the solid catalyst component, propylene is supplied at a propylene partial pressure of 0.03 MPa ( It was introduced until it reached Gauge) and reacted at 55 ° C. for 4 hours. After completion of the reaction, the solid catalyst component was washed several times with n-heptane, and carbon dioxide was supplied and stirred for 24 hours.
As a pre-stage of the main polymerization, in a polymerization tank (homopolymerization tank) with an internal volume of 200 liters, the treated solid catalyst component was converted to Ti atoms in the component at a rate of 3 mmol / hour and 600 ml of triethylaluminum. Diphenyldimethoxysilane was supplied at a rate of 15 mmol / hour at a mmol / hour, and the reaction was carried out at a polymerization temperature of 70 ° C. and a propylene pressure of 2.7 MPa (Gauge). At this time, it adjusted so that it might become a predetermined molecular weight using hydrogen. Subsequently, powder is continuously extracted from the former stage polymerization tank and transferred to the latter stage (random copolymerization tank). In the latter stage polymerization tank (random copolymer tank), propylene and ethylene were supplied at a polymerization temperature of 55 ° C. to carry out random copolymerization. At this time, the supply ratio of propylene and ethylene was adjusted so that the content of ethylene units became a predetermined value.
The total amount of the circulating medium for cooling (composition: hydrogen 0.3% by mass, ethylene 38% by mass, propylene 58% by mass, propane 3.7% by mass) is 160 kg / hr, and 110 kg / hr from the bottom of the polymerization tank, 50 kg / hr was supplied from the polymerization tank surface. The height position to be supplied from the side surface was 0.55 m with respect to the height of the powder tank of 0.8 m. After the operation for 6 days, the inside of the polymerization tank was checked, and no polymer was found on the surface of the stirring blade.

Comparative Example In the examples, the supply amount of the cooling circulation medium was changed from the supply amount 110 kg / hr from the bottom surface of the polymerization tank to 160 kg / hr and the supply amount from the side surface of the polymerization tank 50 kg / hr to 0 kg / hr (bottom surface). Was supplied in the same manner as in the example. After the operation for 6 days, the inside of the polymerization tank was confirmed, and adhesion of the polymer was observed on the surface of the stirring blade and the surface of the polymerization tank.

It is the schematic which shows the one aspect | mode of the polymerization tank of the back | latter stage in the propylene-ethylene block copolymer manufacturing apparatus which is an example of the polyolefin vapor phase polymerization apparatus of this invention.

Explanation of symbols

1 Subsequent polymerization tank 2 Monomer supply pipe 3 Polymer discharge pipe 4 Cooling medium supply mechanism 5 Stirring blade 6 Gas phase part 7 Powder part

Claims (5)

A method for producing a polyolefin by continuous gas phase polymerization using an olefin polymerization catalyst, wherein in a polymerization having a plurality of polymerization stages, a homopolymer of propylene or the like in the presence of a stereoregular catalyst in a first polymerization tank In the second polymerization tank, in the presence of the crystalline polypropylene, propylene and other α-olefins are produced in the second polymerization tank. When the propylene block copolymer is produced by random copolymerization, the monomer is supplied from the monomer supply pipe provided in the gas phase portion at the upper part of the second polymerization tank, and the cooling liquid circulation medium is added to the stirring blade. fed from a single point of the bottom surface and at least a side surface of the second polymerization vessel in the second polymerization vessel having, with respect to the supply amount of the cooling liquid circulation medium from the bottom, the The supply amount of the cooling liquid circulation medium from the side surface of the two polymerization tanks is 0.05 to 0.5 times the mass, and the cooling liquid circulation medium is supplied to the powder part of the second polymerization tank A method for producing polyolefin. The method for producing a polyolefin according to claim 1, wherein the cooling liquid circulation medium is supplied from a height of ½ or more of the height of the powder portion of the second polymerization tank having a stirring blade.   High solidity obtained by using a solid catalyst component obtained by using (A) (a) a magnesium compound and (b) a titanium compound, (B) an organoaluminum compound and (C) an electron donating compound. The method for producing a polyolefin according to claim 1, which is a regular catalyst. The method for producing a polyolefin according to any one of claims 1 to 3, wherein the amount of the random copolymer produced in the second polymerization tank is 5 to 50 mass% with respect to the propylene block copolymer. The copolymerization ratio of propylene and other α- olefin in the random copolymer produced in the second polymerization tank (mass ratio) according to claim 1 which is 20 to 85/80 to 15 Production method of polyolefin.

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