JPS6315927B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a gas phase polymerization method for directly converting gaseous alpha-olefins into polymers.
More specifically, the present invention relates to a method for continuously producing a high quality α-olefin block copolymer using a fluidized bed reactor or a fluidized bed reactor equipped with a stirrer. Crystalline α-olefin polymers have been produced industrially since the invention of α-olefin stereoregular catalysts by Ziegler and Natsuta et al. The most important industrial production method proposed to date is the so-called solvent polymerization method, in which a catalyst is dispersed in a liquid inert solvent, and α-olefin is supplied for polymerization. However, in such solvent polymerization method, after the completion of polymerization,
After deactivating the catalyst and extracting the catalyst residue, the polymer particles are separated from the inert solvent and further dried to obtain a product polymer. On the other hand, separated inert solvents are usually industrially low-molecular-weight, low-crystalline polymers and catalyst residues dissolved in inert solvents, purified, and reused, which is very complex and requires energy. Requires an intensive process. In order to overcome this problem, many proposals have already been made regarding gas phase polymerization methods in which α-olefins are polymerized in the gas phase in the absence of a substantially liquid inert solvent. However, these polymerization methods in the gas phase have many problems that need to be overcome compared to solvent polymerization methods. In other words, in the method of polymerizing by stirring polymer particles in the gas phase, it is extremely difficult to achieve uniform mixing compared to solvent polymerization, which tends to generate locally high temperature areas, and also makes it difficult to polymerize the catalyst. Even when added to the system, it is difficult for the solid catalyst component to disperse quickly, which tends to cause localized areas of high temperature. Furthermore, heat transfer through the walls of the reactor is also significantly poorer than in the solvent polymerization method, so it is extremely difficult to remove the polymerization heat from the walls of the reactor, which is usually carried out in the solvent polymerization method. In order to overcome these problems, a bed is formed in which the solid catalyst component and/or polymer particles and/or dispersion containing the solid catalyst component are fluidized by an upward flow of a gas mainly composed of α-olefin. The polymerization reaction of α-olefin is carried out there, and the final reaction gas is introduced into a circulation system having an external heat exchanger, cooled, and then fed into the fluidized bed again to remove the polymerization reaction heat. A polymerization method using a so-called fluidized bed reactor or a fluidized bed reactor equipped with a stirrer has been proposed. Many of the gas phase polymerization methods proposed so far are
Block copolymerization is continuous polymerization, but essentially requires a multi-step polymerization process using a composite catalyst containing a solid catalyst. Problems where the composition is non-uniform among polymer particles, causing lumps to appear in the molded product, significantly deteriorating the appearance of the molded product, and significantly deteriorating mechanical properties such as tensile properties and impact strength. There is. As a method to improve this problem in the continuous production of block copolymers, Japanese Patent Publication No. 53-25585 and Japanese Patent Publication No. 49-12589 disclose a method in which multiple reactors are connected in a solvent polymerization method. A method for producing high quality block copolymers by polymerization has been proposed. However, in the gas phase polymerization method, the method of polymerizing by connecting multiple reactors is extremely difficult compared to the solvent polymerization method. In other words, depending on the structure of the block copolymer to be produced, the adhesion of the polymer particles increases significantly, making it difficult to generate localized high temperature regions in a fluidized bed reactor or a fluidized bed reactor equipped with a stirrer. If a sufficient amount of circulating gas is supplied to the reactor for the purpose of prevention and removal of the heat of polymerization, there is a problem that abnormal flow phenomena such as slugging occur. Furthermore, there is a problem in that piping between reactors frequently becomes clogged during the transfer of polymer particles. As a result of intensive studies to overcome such problems, the inventors of the present application have discovered a method for stably producing block copolymers with fewer lumps and excellent mechanical properties by continuous polymerization, and the present invention I reached it. That is, the present invention uses a fluidized bed reactor or a fluidized bed reactor with a stirrer in the presence of a Ziegler-Natsuta catalyst to react with propylene alone or with substantially no liquid inert medium. α-olefins having 2 to 8 carbon atoms, preferably α-olefins having 2 to 4 carbon atoms, copolymerized as a result with propylene
Olefin, most preferably 6 mol% ethylene
a first step of polymerizing or copolymerizing with propylene and an α-olefin having 2 to 8 carbon atoms, preferably 2 to
4 α-olefin, most preferably ethylene
In block copolymerization, which consists of a second step in which copolymerization is carried out to a concentration of 10 mol% or more, the first step involves continuous polymerization using at least two reactors, preferably three to seven reactors connected in series. In the second stage, at least one reactor, preferably 2 to 5 reactors are connected in series for continuous polymerization, and the second stage includes a step of copolymerizing 25 to 80 mol% of propylene. A method for producing a block copolymer, characterized in that the amount of polymerization in the step is 2 to 40% by weight, preferably 2 to 30% by weight, most preferably 2 to 25% by weight of the final polymer. be. The first stage of the block copolymerization according to the invention is carried out with at least 2 groups, preferably 3 to 7 groups. When this step is carried out in one unit, the resulting polymer has a non-uniform composition among the particles, and a high quality polymer cannot be obtained. A high quality polymer can be obtained by linking two or more groups, preferably three or more groups. Additionally, at this stage, generally speaking, as the number of reactors connected increases, the residence time distribution of the catalyst narrows and polymer particles with a uniform composition can be obtained, but even if eight or more reactors are connected, there is no improvement effect. few. The second stage is carried out with at least one, preferably 2 to 5. Although one group may be used in this step, it is preferable to connect two or more groups because a polymer having a more uniform composition can be obtained. Although it is possible to connect six or more groups, the improvement effect is small as in the first stage. In the present invention, the α-olefin having 2 to 8 carbon atoms to be copolymerized with propylene includes ethylene, 1-butene, 1-pentene, and hexene-1.
1, heptene-1, pentene-1, 4-methyl-
Examples include pentene-1 and octene-1. Among them, ethylene and butene-1 are preferred because of their high polymerization rate, and ethylene is particularly preferred. In addition, in each stage of polymerization, it is possible to carry out the polymerization by changing the composition or type of monomers supplied to each reactor, but in the second stage, propylene is
It is essential to include a step of copolymerizing 80 mol%. By including this step in the second step and making the amount of polymerization in this step at least 2% by weight of the final polymer, it is possible to produce a polymer with extremely excellent impact resistance and embrittlement temperature. However, if the amount of polymerization in this step is more than 40% by weight of the final polymer, it is not preferable because the adhesive force of the polymer particles increases significantly and it becomes difficult to carry out stable polymerization. By reducing the amount of polymerization in this step to 30% by weight or less, a polymer with extremely low adhesion can be obtained, and
It is preferable that the amount is less than % by weight because a polymer with extremely low adhesive force can be obtained. According to the study results of the present inventors, the angle of repose increases with the adhesive force of polymer particles, but when the angle of repose exceeds 45°, stable polymerization becomes difficult. By carrying out the block copolymerization within the above-mentioned limited range, it becomes possible to produce a polymer of extremely good quality and excellent powder properties. The catalyst used in the present invention is a so-called Ziegler-Natsuta catalyst, that is, a catalyst consisting of a transition metal compound from groups 1 to 2 of the periodic table and an organic compound of a typical metal of groups 1 to 1 of the periodic table, and contains the transition metal compound or the like. It is preferred that the catalyst component used is a solid. Preferable transition metal compounds are compounds containing at least titanium and halogen, among which compounds having the general formula Ti(OR)nXm-n (R represents 1 to 20 carbon atoms, the hydrocarbon group X represents a halogen, A titanium halogen compound represented by m is a number from 2 to 4 and n is a number from 0 to m-1 is preferred. Specific examples of such compounds include TiCl ₄ , TiCl ₃ , TiCl ₂ , Ti(OC ₂ H ₅ )Cl ₃ , Ti
_{( OC6H5} ) _Cl3 , etc. The transition metal compound can be used as the main component itself or as a catalyst component supported on a suitable carrier. Among titanium-halogen compounds, TiCl ₃ is one of the most preferred transition metal compounds in the present invention, but it is known to take α, β, γ, and δ crystal forms, and TiCl 3 has three or more carbon atoms. For stereographic polymerization of α-olefin, α, γ and δ types of TiCl ₃ having genus crystal forms are preferred. TiCl ₃ is generally obtained as a TiCl ₃ composition by reducing TiCl ₃ with hydrogen, metallic aluminum, metallic titanium, an organoaluminum compound, an organomagnesium compound, or the like. preferable
TiCl ₃ compositions are produced by reducing TiCl ₄ with metallic aluminum, further reducing it with so-called TiCl ₃ AA and TiCl ₄ organoaluminium compounds activated by mechanical grinding, and then using a complexing agent and a halogen compound. It is activated by In the present invention, the latter is particularly preferred. When the TiCl ₃ composition was polymerized for 4 hours at 65°C in combination with diethylaluminium chloride in the presence of hydrogen in liquefied propylene,
Particularly preferred are those capable of producing 6000 g or more of polypropylene per gram of TiCl ₃ composition. Such a TiCl ₃ composition is disclosed in Japanese Patent Application Laid-Open No. 47-34478.
No. 76196, Japanese Patent Application Laid-Open No. 1983-76196,
Publication No. 33289, Japanese Unexamined Patent Application Publication No. 11985-1985, Patent Application No. 1983
It can be manufactured by the method disclosed in, for example, Japanese Patent No.-21252. When a transition metal compound is used as a catalyst component supported on a suitable carrier, examples of the carrier include various solid polymers, especially α-olefin polymers, various solid organic compounds, especially solid hydrocarbons, and various solid inorganic compounds. In particular, oxides, hydroxides, carbonates, halides, etc. can be used. Preferred carriers are magnesium compounds, ie magnesium halides, oxides, hydroxides,
Hydroxyhalides, etc. Magnesium compounds can also be used as complexes with other solid substances mentioned above. A commercially available magnesium compound can be used as it is, but it can be mechanically pulverized, dissolved in a solvent and then precipitated, or treated with an electron-donating compound or active hydrogen compound, or treated with a Grignard reagent, etc. Preferably, it is a magnesium compound obtained by decomposing an organomagnesium compound. In many cases, it is preferable to use these operations in combination to obtain a preferable magnesium compound, and these operations may be carried out in advance when producing the carrier, or may be carried out when producing the catalyst component. Particularly preferred magnesium compounds are halogenated magnesium compounds, and particularly preferred transition metal compounds are the aforementioned halogenated titanium compounds. Such a supported catalyst component consisting of titanium, magnesium, and halogen is one of the most preferred catalyst components in the present invention, and is disclosed in Japanese Patent Publication No. 47-41676, USP 3642746, Japanese Patent Application Laid-open No. 49-86482, and Japanese Patent Application Laid-open No. 1986-51. -92885 publication, JP-A-52-74684 publication,
JP-A-53-39991, JP-A-54-2988,
JP-A-54-3183, JP-A-54-17988,
It can be produced by the methods disclosed in JP-A-54-112982, JP-A-54-112983, and Japanese Patent Application JP-A-54-107471. α- with 3 or more carbon atoms
In order to carry out stereophysical polymerization of olefins, it is preferable to use a supported catalyst component consisting of titanium, magnesium, and halogen containing an electron donor compound. Preferred organic compounds of typical metals of Groups ~ of the Periodic Table are organoaluminum compounds, particularly those with the general formula ReAlX _3-e (R is 1 to 1 carbon atoms).
20. Organoaluminum compounds represented by a hydrocarbon, X represents hydrogen or halogen, and e is a number from 1 to 3 are preferred. Specific examples of such compounds include triethylaluminum, triisobutylaluminum, diethylaluminum hydride, diethylaluminum chloride, diethylaluminum bromide, ethylaluminum sesquichloride, ethylaluminum dichloride, and the like. The most preferred compound is
triethylaluminum, diethylaluminium chloride and mixtures thereof. The catalyst used in the present invention consists of a solid catalyst component made of the transition metal compound and the organometallic compound, but an electron-donating compound can be further used in combination to improve activity and/or stereoregularity. . Such electron-donating compounds include ethyl acetate, ε-caprolactone, methyl methacrylate,
Ethyl benzoate, ethyl P-anisate, methyl P-toluate, esters or acid anhydrides such as phthalic anhydride, ether compounds such as di-n-butyl ether, diphenyl ether, daidalime, tri-n-butyl phosphite , triphenyl phosphite, hexamethylene phosphoric triamide, and other organic phosphorus compounds. In addition, ketones, amines, amides, thioethers, etc. can also be used. Preferred electron-donating compounds are esters and phosphites, sometimes titanium, magnesium,
Aromatic monocarboxylic acid esters are preferred for supported catalyst components comprising halogens. As mentioned above, the catalyst used in the present invention consists of at least two components: a solid catalyst component and an organometallic compound catalyst component. The solid catalyst component may be a mixture with an α-olefin polymer obtained by prepolymerizing 100 parts by weight or less of α-olefin per 1 part by weight of the solid catalyst component. Next, preferred embodiments of the reactor are shown in FIGS. 1 and 2. As shown in FIG. 1, the reactor has a cylindrical shape with a length to inner diameter ratio ranging from 1 to 6. Alternatively, as shown in FIG. 2, it is also possible to further have a deceleration zone in the upper part having a diameter less than twice the diameter of the straight body part. The reactor can furthermore have a stirrer 6 in order to obtain a homogeneous fluidized bed or an insert 7 in order to further prevent particle scattering. Although the stirrer 6 is not necessarily essential in the polymerization of the present invention, it is used for the purpose of preventing abnormal flow phenomena such as slugging and channeling, and for uniformly dispersing the catalyst when supplying the catalyst, and for dispersing the polymer at the bottom of the reactor. It can be equipped for the purpose of preventing the adhesion of The stirring blade is preferably a multi-stage paddle blade, but is not particularly limited, and a stirring speed of 5 m/sec or less at the tip of the stirring blade is sufficient. Although the insert 7 is not absolutely essential, it can be provided for the purpose of preventing the polymer particles or solid catalyst particles from scattering. When the insert is projected in the axial direction, it is preferable that the portion that is not projected be 10% or less of the cross-sectional area of the straight body to greatly prevent scattering. The polymer particles are kept in a fluid state by introducing a gas containing α-olefin into the reactor from the gas distribution device 8. The gas distribution device 8 is not particularly limited, but has no clogging of holes during the polymerization process, no occurrence of abnormal flow phenomena such as channeling, and no occurrence of localized high temperature regions. It is preferable to have a structure that maintains a stable fluidized state, and for this purpose, a perforated plate, a bubble catch, a pipe sparger, etc. may be used. especially,
Pipe spargers or bubble caps with holes below the horizontal are preferred. Further, the gas distribution device can be arranged in multiple stages of two or more stages. There are no particular limitations on the place where the catalyst is supplied, but the method of supplying the solid catalyst component into the fluidized bed is as follows:
There is less scattering into the circulation system, and the catalyst components are dispersed.
This is preferable because it can be achieved in a short time. It is preferable to feed the organoaluminum compound or the electron-donating compound when the solid catalyst component is sufficiently dispersed because local reactions are less likely to occur, and most preferably from above the fluidized bed. Further, the electron-donating compound may be supplied to the same place as the organoaluminum compound. The feeding ratio of the catalyst component is as follows: solid catalyst component is mixed with _TiCl3
In this case, organoaluminum compound/TiCl ₃
The molar ratio of is preferably 1 to 100, and particularly preferably 3 to 50. The electron donating compound is normally used in an amount of 1 mol or less per 1 mol of TiCl ₃ or the organoaluminum compound. The catalyst components are supplied either continuously or intermittently, but in an amount commensurate with the amount of catalyst to be withdrawn as the polymer is withdrawn. In this way, polymerization proceeds with the solid catalyst component dispersed in the polymer particles serving as a polymerization active center. It is essential that the polymerization reaction proceed under conditions in which substantially no liquid medium is present in the reactor and the polymer particles do not melt into agglomerates. Detailed polymerization conditions are temperature range from 40 to 100℃, 1 to 50Kg/cm ² (G)
The process is carried out under conditions in which the α-olefin is not substantially liquefied in the pressure range of . As long as the temperature and pressure are within the above range, it may be freely changed in each reactor. Although hydrogen is preferably added to the polymerization for the purpose of adjusting the melt flowability of the product, it is also possible to include a step of removing hydrogen in the second stage of the polymerization. The monomers and hydrogen consumed in the reaction are supplied continuously or intermittently. The location where it is supplied is not particularly limited and may be any of the circulation line, freeboard, and floor. Under steady state conditions, polymerization proceeds in a flow of monomer-based gas having an upward flow at least sufficient to fluidize the polymer particles. In order to achieve uniform fluidization and prevent the occurrence of localized high temperature regions, the gas upward flow should be in the range of 1.5 to 10 times, preferably 2 to 6 times, the fluidization initiation velocity (Umf) of the final polymer particles. Preferably driving. Unreacted gas that did not react in the bed is transferred from 10 to the circulation system. Solid components such as polymer particles entrained in the unreacted gas are removed by a cyclone and/or a filter, the pressure is increased by a compressor, the gas is cooled by a heat exchanger, and then the gas is supplied to the gas distribution device 8.
Although the positions of the compressor and heat exchanger can be reversed, the conditions are such that when the monomer is cooled within the polymerization pressure range of the present invention, such as propylene, part or most of the gas is liquefied. In this case, it is difficult to stably increase the pressure of a gas-liquid mixture using a compressor.
It is preferable to circulate the compressor and the heat exchanger in this order. The polymer particles separated by the cyclone can be returned to the reactor or removed from the system. Although most of the polymerization heat is removed by the heat exchanger 9, the polymerization must be further controlled to achieve a predetermined polymerization temperature. In the bed, heat exchange between the polymer particles and the circulating gas occurs relatively quickly, and the circulating gas temperature at the bed outlet and the polymerization temperature of the bed approximately coincide. Therefore, in order to achieve a predetermined polymerization temperature, the circulating gas temperature at the reactor inlet is estimated and set in advance, taking into account the heat capacity of the polymerization gas and the circulating gas flow rate, and then the circulating gas temperature at the reactor inlet is set. Preferably, the gas temperature is adjusted to achieve the desired polymerization temperature. The method of the present invention will be explained in more detail with reference to Examples below, but the present invention is not limited only by these Examples. The results of Examples and Comparative Examples are shown in Tables 1 to 4, and the physical property values in the tables were measured according to the following criteria. Melt index ASTM D1238-57T Bending rigidity ASTM D747-58T Picasso softening point ASTM D1525 Brittle temperature ASTM D746 Drop impact strength: A 1 mm (thick) injection molded sheet was placed in a Dupont impact tester, and the tip was
Touch a core with a 6.3mm ball and place a 1.5
A Kg weight was allowed to fall naturally at different heights to find the maximum energy that would not cause it to break. Measured at 20℃
and -10℃. Tensile test: The yield stress (YS), stress at break (US), and elongation at break (UE) were measured in accordance with ASTM D638-68T. The intrinsic viscosity (hereinafter abbreviated as [η]) was measured at 135°C using tetralin solvent. To measure the particles, form a film with a thickness of 30 mm using a T-die extruder, and count the particles with a diameter of 50 mm or more/cc.
It was converted into According to the results of studies conducted by the present inventors, the surface gloss of the formed product was good when it was 1000 or less. The appearance of the molded product was observed by molding a sheet with a thickness of 1 mm and a length and width of 16 cm using an injection molding machine. Example 1 (1) Synthesis of catalyst (200) 45.5% hexane and 11.8% TiCl ₄ were charged into an autoclave equipped with a stirrer, and while keeping this solution at -10 to -5°C, hexane was added.
43.2 and diethylaluminum chloride 13.5
A solution consisting of was added dropwise over 3 hours while stirring. The reaction mixture was then held at -10 to 0°C for 15 minutes, then heated to 65°C over 2 hours, and kept under stirring at 65°C for an additional 2 hours. The solid (abbreviated as reduced solid) of the reaction mixture was then separated from the liquid phase and washed six times with 50 g of hexane to remove the hexane. () The resulting reduced solid was suspended in 92 hexane and diisoamyl ether 19.6
was added. After stirring this suspension at 35° C. for 1 hour, the resulting solid (abbreviated as ether-treated solid) was separated from the liquid phase and washed 6 times with 50° C. of hexane, and then the hexane was removed. A 40% by volume solution of TiCl ₄ in hexane 60 was added to the resulting ether treated solid and the suspension was stirred at 70° C. for 2 hours. The resulting solid was then separated from the liquid phase and
After washing with hexane 10 times, the hexane was removed and drying was performed. The solid obtained in this way is referred to as a TiCl ₃ solid catalyst (). (2) Propylene-ethylene block copolymerization As shown in Figure 3, six reactors were connected in series to carry out propylene-ethylene block copolymerization continuously. Each reactor was a fluidized bed reactor with an internal volume of 1 m ³ and equipped with a stirrer, as shown in FIG. In reactor A, 4.5 g/hr of titanium trichloride solid catalyst (), 40 g/hr of diethylaluminum chloride, 8 g/hr of triethyl aluminum, and methyl methacrylate were used as catalysts.
Polymerization was carried out by feeding propylene and hydrogen continuously at a rate of 2.9 g/hr. The polymer particles were extracted from the bottom of each reactor together with a portion of the circulating gas and transferred to the next reactor for continuous polymerization. In reactors A, B, C, and D, propylene was polymerized, and in reactors E and F, ethylene and propylene were copolymerized. Also,
The polymer particles taken out from reactor C were charged into reactor D under pressure with propylene after separating most of the unreacted monomers using a cyclone. The polymer particles were transferred between the other reactors along with the unreacted monomers using a pressure difference. Polymerization conditions are shown in Table 1. During the polymerization period, reactors A to G maintained the circulating gas flow rate at a rate of 80 to 120 m ³ /hr using a compressor installed in the circulation system. This was in the range of 2 to 3 times the minimum fluidization rate of the polymer particles. Continuous polymerization continued for 12 hours, and there were no abnormal flow phenomena in the reactor or blockages in the piping during this period, and there were no problems. The angle of repose of the polymer particles at the outlet of reactor F was 38°. A small amount of polymer was sampled from the outlet ports of reactors D and F and [η] was measured and found to be 1.79 and 2.57 (dl/g), respectively.
Further, the ethylene/propylene reaction ratio (molar ratio) in reactors E and F was calculated from the material balance and was 54/46 and 59/41, respectively.
The obtained polymer particles are transferred to a stirring mixing tank, and 3 ml of propylene oxide is added per 1 kg of polymer particles.
and 0.3 ml of water were added, treated at 80°C for 30 minutes, and then dried to obtain a white powdery polymer. The obtained polymer particles are added with known additives and then extruded into strands using an extruder.
It was made into a pellet and its physical properties were measured. 4th result
Shown in the table.

[Table] Comparative Example 1 Two reactors G and H having the same structure as Example 1 were connected in series to carry out propylene-ethylene block copolymerization continuously. In reactor G, 3.1g/hr of titanium trichloride solid catalyst () was added as a catalyst.
Diethylaluminum chloride was supplied at 30g/hr, triethylaluminum at 6g/hr, methyl methacrylate at 1.9g/hr, and propylene and hydrogen were continuously supplied. The polymer particles were transferred from the lower part of the reactor together with unreacted monomers to reactor H, and propylene and ethylene were supplied to carry out polymerization. Polymerization conditions are shown in Table 2. A small amount of polymer was sampled from the outlet ports of reactors G and H and [η] was measured and found to be 1.78 and 2.55 (dl/g), respectively. Further, the ethylene/propylene reaction ratio (molar ratio) in reactor H was 55/45 as calculated from the material balance. These results show that a block copolymer having an average structure almost the same as that of Example 1 was obtained. The obtained polymer particles were treated in the same manner as in Example 1, and then made into pellets and their physical properties were measured. In Example 1, the appearance of the molded product was excellent with less occurrence of lumps compared to Comparative Example 1, and it was also found that the embrittlement temperature, falling weight impact strength, and elongation at break (UE) were extremely excellent. Recognize.

[Table] Example 2 (1) Synthesis of catalyst (200) Hexane 52 and TiCl ₄ 13.5 were charged into an autoclave equipped with a stirrer, and hexane 35 and diethyl aluminum chloride were mixed while keeping this solution at -10 to -5°C. A solution consisting of 16.5 was added dropwise over 4 hours while stirring. The temperature was then raised to 105°C, and stirring was further continued at 105°C for 2 hours. The solid obtained by standing at room temperature was separated from the liquid phase, and further washed six times with 50 ml of hexane to obtain a heat-treated solid. () The obtained heat-treated solid was suspended in 120 toluene, to which were added 26 kg of di-n-butyl ether and 28 kg of iodine, and the mixture was heated at 95°C for 1 hour.
Stir for hours. The solid obtained by standing at room temperature was separated from the liquid phase, washed six times with 50 ml of hexane, and then dried. The solid thus obtained is referred to as a TiCl ₃ solid catalyst (). (2) Propylene-ethylene block copolymerization As shown in Figure 4, seven fluidized bed reactors with an internal volume of 1 m ³ having the same structure as in Example 1 and equipped with a stirrer were connected in series to continuously produce propylene. - Ethylene block copolymerization was carried out. Reactor I, J,
K and L are reactors A, B, C, and D of Example 1, respectively, except that the catalyst component supplied to reactor I was changed from titanium trichloride solid catalyst () to titanium trichloride solid catalyst (). It was carried out under the same polymerization conditions. The polymerization conditions of reactors M, N, and O were changed to the third
Shown in the table. Also, from reactor K to L, from L to M, from M to N
The polymer particles are transferred to the reactor by separating most of the unreacted monomers in a cyclone, then pressurized with monomers, and then charged into the reactor. Transfer between other reactors uses the pressure difference to separate the unreacted monomers. It was transported along with the The polymerization continued for 12 hours, but there was no abnormal flow phenomenon in the reactor, and there was no blockage in the piping, so there were no problems. A small amount of polymer was sampled from reactors L and O and [η] was measured and found to be 1.81 and 3.01 (dl/g), respectively. In addition, the ethylene/propylene reaction ratio (molar ratio) in reactors L, N, and O was calculated from the material balance and was 44/56, 47/53, respectively.
It was 86/14. The obtained polymer was prepared in Example 1.
After being treated in the same manner as above, the pellets were made into pellets, and the physical properties were measured. Table 4 shows the results. In Example 2, there were no lumps and the appearance of the molded product was satisfactory. It is also clear that the physical properties are extremely excellent, especially in embrittlement temperature, falling weight impact strength, and elongation at break (UE). In addition, reactor O
The angle of repose of the polymer particles extracted from was 35°.

【table】

【table】

【table】 [Brief explanation of the drawing]

FIGS. 1 and 2 show an example of a fluidized bed reactor used in the present invention. 1: Fluidized bed reactor main body, 2: Reduction zone, 3:
Hydrogen supply port, 4: Propylene supply port, 5: Ethylene and α-olefin supply port, 6: Stirrer,
7: interpolant, 8: gas distribution device, 9: heat exchanger,
10: unreacted gas outlet, 11: solid catalyst supply port,
12: polymer extraction port, 13: organometallic compound and electron donating compound supply port, 14: cyclone, 15: filter, 16: compressor, 17: jacket, 18: fluidized bed level. FIGS. 3 and 4 show an example of the production form of the block copolymer of propylene and α-olefin having 2 to 8 carbon atoms according to the present invention.

Claims (1)

[Claims] 1 Propylene alone or in the substantially absence of a liquid inert medium in the presence of a Ziegler-Natsuta catalyst using a fluidized bed reactor or a fluidized bed reactor equipped with a stirrer. , or a C2-8 α-olefin copolymerized with propylene as a result of 6
A first stage of polymerization or copolymerization so that the amount is mol % or less, and a second stage that is copolymerized so that the α-olefin having 2 to 8 carbon atoms to be copolymerized with propylene is 10 mol % or more. In the block copolymerization, in the first stage, at least two reactors are connected in series for continuous polymerization, and in the second stage, at least one reactor is continuously polymerized,
A method for producing a block copolymer, which comprises a step of copolymerizing 25 to 80 mol% of propylene in the second step, and the amount of polymerization in this step is 2 to 40% by weight of the final polymer. 2 a The reactor has a cylindrical straight body with a length-to-inner diameter ratio of 1 to 6, and in some cases further has a stirrer inside it, and the reactor has an α- Most of the olefin-containing gas is supplied from the bottom at a rate in the range of 1.5 to 10 times the fluidization initiation speed of the α-olefin polymer particles, and the polymer particles present inside the reactor are fed with the gas flow or further. At this time, most of the inside of the reactor is fluidized using a rotating stirrer.
Kg/cm ² , maintained at 40 to 100° C. under conditions in which the α-olefin is not substantially liquefied, b) the α-olefin polymer particles in which a solid catalyst component containing at least titanium and halogen has been fluidized; c) Polymerize the α-olefin by supplying the organic aluminum compound to the bed of the reactor and supplying the organoaluminum compound to any position in the reactor, and c. and/or introduced into a filter and entrained. α-olefin polymer particles and/or solid catalyst components are separated; d α-olefin polymer particles and/or entrained in a cyclone and/or filter;
Alternatively, the gas consisting of α-olefin from which fixed catalyst components have been separated and removed is pressurized by a compressor, and then cooled to a temperature lower than the internal temperature of the reactor by passing through a heat exchanger. The method according to claim 1, characterized in that the α-olefin polymer particles are fed from the bottom of the reactor, and at least a portion of the α-olefin polymer particles present inside the reactor are extracted from the bottom of the reactor.