JPH0429687B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing polypropylene, and more specifically, the present invention relates to a method for producing polypropylene, which mainly comprises an activated titanium catalyst component prepared using a magnesium compound having a specific average particle size and particle size distribution, and an organometallic compound. The present invention relates to a method for producing polypropylene with uniform particle size, high bulk density, and high stereoregularity with high activity by polymerizing propylene using a catalyst. Various methods have been proposed to obtain polypropylene with high stereoregularity using catalysts consisting of solid catalyst components containing magnesium and titanium and organometallic compounds (Japanese Patent Application Laid-open No. 74103/1983, Publication No. 56-99207, Publication No. 56-115301,
No. 56-120711, No. 57-166295, No. 57
−63308, etc.). However, in these conventional methods, the particle size of the obtained polymer is irregular, and in particular, there is a relatively large amount of fine powder with a particle size of less than 150 μm, which often causes various troubles. Therefore, if polymerization is carried out using a catalyst prepared to narrow the particle size distribution of the produced polymer particles, the above troubles will be resolved, but other problems will occur, such as a decrease in the bulk density of the produced polymer particles. There are drawbacks. An object of the present invention is to efficiently produce a polymer (polypropylene) having a narrow particle size distribution with high bulk density and uniform particle size, and the present inventors have conducted extensive research from this viewpoint. As a result, it was discovered that the object could be achieved by using a magnesium compound having a specific average particle size and particle size distribution for use in preparing an activated titanium catalyst component, and the present invention was realized. It was completed. That is, the present invention uses a catalyst mainly composed of (A) a reaction product of a magnesium compound and titanium tetrahalide and (B) an organoaluminum compound,
In the method of producing polypropylene by homopolymerizing or copolymerizing propylene, the general formula Mg
(OR ¹ ) _o X ¹ _2-o (wherein, R ¹ represents an alkyl group having 1 to 10 carbon atoms, X ¹ represents a halogen atom, and n is
Indicates a real number between 1.0 and 2.0. ), and has an average particle size of 20 to 60μ, and a particle size distribution in which particles of 10μ or less account for 10% by weight or less, may be used as the magnesium compound in component (A). The present invention provides a method for producing characteristic polypropylene. As mentioned above, the magnesium compound used in the present invention is represented by the general formula Mg(OR ¹ ) _o X ¹ _2-o , and specifically includes magnesium dimethoxide, magnesium diethoxide, magnesium dipropoxide, magnesium Examples include magnesium dialkoxides such as dibutoxide, and magnesium monohalogenated monoalkoxides such as magnesium monochloromethoxide, magnesium monochloroethoxide, and magnesium monochloropropoxide. In the present invention, among these magnesium compounds, an average particle size of 20 to 60 μ
A magnesium compound having a particle size distribution such that particles of 10 μm or less account for 10% by weight or less is used as the magnesium compound in preparing component (A). Among the above-mentioned magnesium compounds, those with an average particle size of less than 20μ tend to produce fine powder of less than 150μ as polypropylene particles.
Unfavorable in terms of handling. On the other hand, when the average particle size of the magnesium compound exceeds 100μ, coarse particles of polypropylene (1000μ or more) are generated.
is generated, which can easily lead to problems with manufacturing equipment. In addition, the particle size distribution of magnesium compounds is originally
It is preferable that there are no particles smaller than 10μ, but 10% by weight
If the amount is below, the amount of fine powder in the obtained polypropylene particles can be suppressed to a level that does not cause any practical problems. In the present invention, the above-mentioned magnesium compound is used,
This is reacted with titanium tetrahalide to form a catalyst.
Component (A) is prepared. The titanium tetrahalide used here is represented by the general formula TiX ² ₄ . Here, X ² represents a halogen atom such as a chlorine atom, a bromine atom, or an iodine atom. Specific examples of these include TiCl ₄ , TiBr ₄ , and TiI ₄ . These may be used alone or as a mixture.
Among these, it is particularly preferable to use titanium tetrachloride (TiCl ₄ ). Preparation of component (A) of the catalyst used in the method of the present invention is as follows:
Tetrahalogenation is carried out by reacting the above-mentioned magnesium compound with tetrahalogenation. The reaction conditions at this time are not particularly limited, but usually 0.5 to 100% titanium tetrahalide is added to 1 mole of magnesium compound.
mol, preferably in the range of 1 to 50 mol, and 0 to 50 mol.
The reaction is carried out at 200°C for 5 minutes to 10 hours, preferably at 30 to 150°C for 30 minutes to 5 hours. This reaction can also be carried out using an inert solvent such as pentane, hexane, heptane, etc., if necessary. It is also effective to carry out the above reaction in the presence of an electron donating compound, or by reacting the above magnesium compound with an electron donating compound in advance and reacting the resulting product with tetrahalogenation. You can also do that. The electron donating compound used here is usually an organic compound containing oxygen, nitrogen, phosphorus or sulfur. Specific examples include amines, amides, ketones, nitriles, phosphines, phosphoramides, esters, thioethers, thioesters, acid anhydrides, acid halides, aldehydes, and organic acids. More specifically, organic acids such as aromatic carboxylic acids such as benzoic acid and p-oxybenzoic acid; acid anhydrides such as succinic anhydride, benzoic anhydride, and p-toluic anhydride; acetone, methyl ethyl ketone, Methyl isobutyl ketone, acetophenone,
3 or more carbon atoms such as benzophenone and benzoquinone
15 ketones; aldehydes with 2 to 15 carbon atoms such as acetaldehyde, propionaldehyde, octylaldehyde, benzaldehyde, tolualdehyde, naphthaldehyde; methyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate,
Octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl valerate, methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, ethyl crotonate, ethyl bivalate, dimethyl maleate, ethyl cyclohexanecarboxylate, methyl benzoate, Ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, methyl toluate, ethyl toluate, amyl toluate, ethyl ethylbenzoate, methyl anisate, anis C2-18 esters such as ethyl acid, ethyl ethoxybenzoate, ethyl p-butoxybenzoate, ethyl o-chlorobenzoate, ethyl naphthoate, γ-butyrolactone, δ-valerolactone, coumarin, phthalide, ethylene carbonate, etc. number; acid halides having 2 to 15 carbon atoms such as acetyl chloride, benzyl chloride, toluic acid chloride, anisyl chloride; methyl ether, ethyl ether, isopropyl ether, n-butyl ether, amyl ether,
Ethers with 2 to 20 carbon atoms such as tetrahydrofuran, anisole, diphenyl ether, and ethylene glycol butyl ether; Acid amides such as acetic acid amide, benzoic acid amide, and toluic acid amide; Tributylamine, N,N'-dimethylpiperazine, and Examples include amines such as livenzylamine, aniline, pyridine, picoline, and tetramethylethylenediamine; nitrites such as acetonitrile, benzonitrile, and tolnitrile; tetramethylurea, nitrobenzene, and lithium butyrate. Among these, esters, ethers, ketones, acid anhydrides and the like are preferred. Particularly preferred are alkyl esters of aromatic carboxylic acids, such as alkyl esters of aromatic carboxylic acids having 1 to 4 carbon atoms, such as benzoic acid, p-methoxybenzoic acid, p-ethoxybenzoic acid, and toluic acid; Also preferred are aromatic ketones, aromatic carboxylic acid anhydrides such as benzoic anhydride, and ethers such as ethylene glycol butyl ether. The amount of these electron-donating compounds to be used is not particularly limited and may be determined as appropriate depending on various circumstances, but is generally 0 to 10 mol, preferably 0.05 mol, per 1 mol of the magnesium compound. Select within the range of ~5 moles. Component (A) of the catalyst used in the method of the present invention is prepared as described above, but it is also effective to repeat the reaction using titanium tetrahalide as described above, if desired. In the method of the present invention, the reaction product thus obtained is thoroughly washed with an inert solvent such as pentane, hexane, heptane, etc., and used as component (A) (solid catalyst component) of the propylene polymerization catalyst. According to the method of the present invention, the above product (solid catalyst component) is used as the (A) component, and the organoaluminum compound is used as the (B) component, and both (A) and (B) are the main components. Polymerization of propylene is carried out using a catalyst.
Furthermore, it is also effective to use a catalyst in which an electron-donating compound is added as component (C) to both components (A) and (B). When producing polypropylene by polymerizing propylene, the reaction system contains a dispersion of the solid product as component (A), an organoaluminum compound as component (B), and optionally component (C). An electron-donating compound is added as an electron-donating compound, and then propylene is introduced into the system. The polymerization method and conditions are not particularly limited, and any of solution polymerization, suspension polymerization, gas phase polymerization, etc. is possible, and both continuous polymerization and discontinuous polymerization are possible. Taking the case of solution polymerization or suspension polymerization as an example, the amount of the catalyst component added is 0.001 to 1.0 mmol/l, preferably 0.005 to 0.5 mmol/l in terms of titanium atoms of component (A), and ( The ratio of component B) to the titanium atoms in component (A) is 1 to 1000 (molar ratio), preferably 10 to 500 (molar ratio). Further, the amount of component (C) added as desired is 0 to 200 (molar ratio), preferably 0.1 to 100, relative to the titanium atoms in component (A).
(molar ratio). The propylene pressure in the reaction system is preferably normal pressure to 50Kg/ ^cm2 , and the reaction temperature is 30 to 50Kg/cm2.
The temperature is 200°C, preferably 50-150°C. Molecular weight adjustment during polymerization can be carried out by known means, such as hydrogen. In addition, the reaction time is 10 minutes ~
The time period may be appropriately selected from 10 hours, preferably from 30 minutes to 5 hours. In the method of the present invention, an organoaluminum compound is used as the component (B) of the catalyst, and the general formula
The formula AlR ³ _k X ³ _3-k is widely used.
R ³ is an alkyl group, cycloalkyl group, or aryl group having 1 to 10 carbon atoms, k is a real number between 1 to 3, and X ³ represents a halogen atom such as chlorine or bromine. Specifically, trimethylaluminum,
Trialkylaluminum compounds such as triethylaluminum, triisopropylaluminum, triisobutylaluminum, trioctylaluminum, diethylaluminum monochloride, diisopropylaluminum monochloride,
Dialkyl aluminum monohalides such as diisobutyl aluminum monochloride and dioctyl aluminum monochloride are preferred, and mixtures thereof are also preferred. In addition, the electron-donating compound that is component (C) of the catalyst used as necessary in the method of the present invention may be the same as that used in the preparation of component (A) of the catalyst described above. I can do it. Furthermore, in this case, the electron donating compound as component (C) is
The compound may be exactly the same as that used in the preparation of component (A), or it may be a different compound. The polypropylene that can be produced by the method of the present invention is not only a propylene homopolymer obtained by homopolymerizing propylene, but also α-polymers of propylene and ethylene, butene-1, hexene-1, octene-1, 4-methyl-pentene-1, etc. Examples include propylene copolymers copolymerized with olefins. According to the method of the present invention, the activity of the catalyst used is extremely high, and the resulting polypropylene has high stereoregularity, resulting in a high product value. Moreover, since the magnesium compound in the solid catalyst component, which is component (A) of the catalyst, has a specific average particle size and particle size distribution, the resulting polypropylene has a relatively uniform particle size distribution. It has the advantage of being narrow, easy to handle, and having a large bulk density. Therefore, the method of the present invention can be effectively used in producing polypropylene with excellent properties as described above. Next, examples of the present invention will be shown. Note that all operations in the following examples were performed under an argon stream. Further, the catalytic activity and stereoregular polymer yield (IY) determined in the examples were defined as follows. Catalytic activity: Weight of total polymer produced per gram of titanium atom in 2 hours (Kg). IY = boiling of polymer insoluble in solvent during polymerization Weight of n-heptane insoluble polymer / weight of total polymer produced x 100
(%) Example 1 (1) Preparation of solid catalyst component In a separable flask with an internal volume of 5 liters, 1500 ml of n-heptane, 100 g (0.88 mol) of Mg(OC ₂ H ₂ ) ₂ and 31.4 g of n-butyl benzoate ( 0.18 mol) was added, the temperature was raised to 40°C, 1670g (8.8 mol) of TiCl ₄ was added dropwise, and the reaction was allowed to proceed at 110°C for 2 hours. The resulting reaction product was washed with n-heptane at 70°C to form a solid. A catalyst component was obtained. The Mg(OC ₂ H ₅ ) ₂ used here has an average particle size of 57μ, and particles of 10μ or less are
% by weight. The amount of titanium supported on the solid catalyst component obtained by the above procedure was measured using a colorimetric method.
It was 35 mg-Ti/g-carrier. (2) Production of polypropylene In a stainless steel autoclave with an internal volume of 1 liter, 400 ml of purified n-heptane, 2.0 mmol of Al(C ₂ H ₅ ) ₃ , 2.0 mmol of Al(C ₂ H ₅ ) ₂ Cl, and p-toluic acid. 0.8 mmol of methyl and 0.02 mmol of the solid catalyst component obtained in (1) above as Ti were added, and the temperature was raised to 70°C. Next, hydrogen was added to the autoclave at a rate of 0.3Kg/cm ² G.
Then, propylene was introduced continuously to make the total pressure 8.0Kg/cm ² G.
The polymerization reaction was carried out for 2 hours. After the polymerization reaction is completed, the insoluble polymer is separated,
The soluble polymer was recovered from the solution by evaporating the solvent. The insoluble polymer was Soxhlet extracted with boiling n-heptane for 6 hours to remove the atactic polymer. The results are shown in Table 1. Example 2 (1) Preparation of solid catalyst component In Example 1 (1), the average particle size of Mg(OC ₂ H ₅ ) ₂ is 50μ, and the content of particles of 10μ or less is 6% by weight. A solid catalyst component was prepared in the same manner as in Example 1 (1), except that a solid catalyst component was used. The amount of titanium supported on this product was 29 mg-Ti/g-support. (2) Production of polypropylene Polypropylene was produced in the same manner as in Example 1 (2) except that the solid catalyst component obtained in (1) above was used. The results are shown in Table 1. Example 3 (1) Preparation of solid catalyst component In Example 1 (1), the average particle size of Mg(OC ₂ H ₅ ) ₂ is 50μ, and the content of particles of 10μ or less is 7% by weight. and 27.0 g of ethyl benzoate instead of n-butyl benzoate.
A solid catalyst component was prepared in the same manner as in Example 1(1) except that (0.18 mol) was used. The amount of titanium supported on this product was 31 mg-Ti/g-support. (2) Production of polypropylene Polypropylene was produced in the same manner as in Example 1 (2) except that the solid catalyst component obtained in (1) above was used. The results are shown in Table 1. Comparative Example 1 (1) Preparation of solid catalyst component Mg(OC ₂ H ₅ ) ₂ in Example 1 (1) has an average particle size of 50μ and the content of particles of 10μ or less is 20% by weight. Example 1 except that
A solid catalyst component was prepared in the same manner as in (1). The amount of titanium supported on this product was 39 mg-Ti/g-support. (2) Production of polypropylene Polypropylene was produced in the same manner as in Example 1 (2) except that the solid catalyst component obtained in (1) above was used. The results are shown in Table 1. Comparative Example 2 (1) Preparation of solid catalyst component In Example 1 (1), Mg(OC ₂ H ₅ ) ₂ having an average particle size of 10 μ and a content of particles of 10 μ or less was 63% by weight was used. Example 1 except for using
A solid catalyst component was prepared in the same manner as in (1). The amount of titanium supported on this product was 39 mg-Ti/g-support. (2) Production of polypropylene Polypropylene was produced in the same manner as in Example 1 (2) except that the solid catalyst component obtained in (1) above was used. The results are shown in Table 1. 【table】

Claims (1)

[Claims] 1. Polypropylene is produced by homopolymerizing or copolymerizing propylene using (A) a reaction product of a magnesium compound and titanium tetrahalide and (B) a catalyst containing an organoaluminum compound as a main component. In the manufacturing method, the general formula Mg(OR ¹ ) _o X ¹ _2-o (wherein,
R ¹ represents an alkyl group having 1 to 10 carbon atoms, and X ¹ represents a halogen atom. Further, n represents a real number from 1.0 to 2.0. ), and the average particle size is 20~
60μ and a compound having a particle size distribution in which particles of 10μ or less account for 10% by weight or less is used as the magnesium compound in the component (A). 2 As a magnesium compound, general formula Mg
The method according to claim 1, in which n in (OR ¹ ) _o X ¹ _2-o is 2.