JP3003718B2 - Method for producing propylene block copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a method for producing a propylene block copolymer using a highly stereoregular polymerization catalyst.

[0002]

2. Description of the Related Art A composition in which a crystalline polymer or copolymer of propylene is produced in a first step and a random copolymer of propylene and another α-olefin is produced in a second step is generally a propylene block copolymer. It is called a polymer. Such a block copolymer has a significantly improved low-temperature impact strength without significantly impairing the excellent rigidity and heat resistance of the polypropylene. Conventionally, the production of propylene block copolymer, generally, using a high stereoregular catalyst, after producing a crystalline polymer or copolymer of propylene in the previous polymerization stage in a homopolymerization tank, in a random copolymerization tank In the latter polymerization step, the polymerization is carried out by random copolymerization of propylene and another α-olefin in the presence of the above-mentioned polymer or copolymer.

[0003]

However, the above-mentioned method for producing a propylene block copolymer has a problem that a gel or a fish eye is generated in the obtained copolymer and the appearance of the product is deteriorated. On the other hand, in continuous polymerization equipment used industrially, the distribution of the catalyst particles in the homopolymerization tank has a distribution, which makes the reaction in the random copolymerization tank non-uniform, which causes gels and fish eyes. Some improvements have been made in the light of that. For example, JP-A-58-49716 and JP-A-55-116716 propose a method in which powder after leaving a homopolymerization tank is classified by a cyclone and fine powder is returned to the homopolymerization tank. However, the classification by particle size does not always correspond to the residence time distribution, so that this method is insufficiently improved. In JP-A-57-195718 and JP-A-58-29811, the supply of the catalyst and the extraction of the powder from the polymerization vessel are performed intermittently, and the catalyst that enters the random polymerization vessel while the residence time is short is reduced. A way to do that has been proposed. However, this method has a problem that the polymerization reaction becomes unstable.

Further, JP-A-57-145115 and JP-A-62-11
No. 6618 proposes a method of selectively inactivating catalyst particles (short-pass catalyst) that have come out with a short residence time by treating the powder that has exited the homopolymerization tank with an electron donor or the like. I have. However, this method is still insufficient in the effect of improving the appearance of the product, and this method causes a new problem of lowering the catalytic activity in the random copolymerization tank. The present invention has been made in view of the above circumstances, and produces a propylene block copolymer having excellent mechanical properties such as rigidity and impact strength, and having reduced gel and fish eyes and improved product appearance with high productivity. The purpose is to provide a way to:

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventors have studied the causes of the occurrence of gels and fish eyes in a propylene block copolymer, and have found that the heterogeneity of the catalyst entering the random polymerization reactor is high. Found that it was not the only cause. In other words, unreacted monomers are circulated and reused in continuous polymerization equipment that is industrially employed, but entrainment of catalyst particles into this circulating system causes gel,
It has been found that this is the main cause of fish eyes, and therefore, it has been found that the generation of gels and fish eyes can be effectively suppressed by adding an electron donor for inactivating catalyst particles to this circulation system. The present inventors have found that this method can achieve the purpose with only a small amount of electron donor that inactivates the entrained catalyst particles. Has the advantage that the catalytic activity does not cause a decrease in activity that is a substantial problem in production, and eliminates the problem of clogging of the circulation system due to the polymer generated by the catalyst particles entrained in the circulation system The present inventors have also found that the present invention has the effect of performing the present invention, and have accomplished the present invention.

Accordingly, the present invention uses a highly stereoregular catalyst obtained by using at least (A) a solid catalyst component containing magnesium, titanium and halogen and (B) an organoaluminum compound, After the production of a crystalline homopolymer or copolymer, the production of a propylene copolymer in which propylene and other α-olefins are randomly copolymerized in the presence of the above-mentioned polymer or copolymer in a subsequent polymerization step In the method, an unreacted monomer is circulated and reused through a circulation channel in the subsequent polymerization step, and an electron-donating compound (however, an aromatic carboxylic acid ester and a general formula ROH (wherein , R
Represents a hydrocarbon group having 5 to 20 carbon atoms. Excluding the alcohol represented by). ) Is provided, a method for producing a propylene block copolymer is provided.

Hereinafter, the present invention will be described in more detail.
In the present invention, 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 is used. Examples of such a catalyst include a highly stereoregular catalyst obtained by using the following components (A) and (B). . (A) A solid catalyst component obtained using (a) a magnesium compound and (b) a titanium compound. (B) an organoaluminum compound. More preferably, the following components (A), (B) and (C) And high stereoregularity catalysts obtained using (A) A solid catalyst component obtained using (a) a magnesium compound, (b) a titanium compound, and (c) an electron donating compound. (B) an organoaluminum compound. (C) an electron donating compound.

Here, the following compounds can be used as the above compounds. (A) Magnesium compound The magnesium compound is not particularly limited, but is preferably magnesium oxide, magnesium hydroxide, dialkylmagnesium, alkylmagnesium halide, magnesium dihalide, magnesium dialkoxide, etc. Specifically, magnesium trichloride, magnesium Diethoxide, magnesium dimethoxide and the like can be suitably used. Further, as the magnesium compound, a solid product obtained by reacting metallic magnesium, a halogen and an alcohol can be suitably used. In this case, the shape of the metallic magnesium is not particularly limited. Therefore, metallic magnesium having an arbitrary particle size, for example, granular, ribbon-shaped, powdered, etc. metallic magnesium can be used. In addition, the surface state of the metallic magnesium is not particularly limited, but those in which a coating such as magnesium oxide is not formed on the surface are preferable. Further, any alcohol can be used, but a lower alcohol having 1 to 6 carbon atoms is preferably used. In particular, it is preferable to use ethanol because a solid product (magnesium compound (a)) that significantly improves the expression of catalytic performance can be obtained. The purity and water content of the alcohol are not limited, but if an alcohol having a high water content is used, magnesium hydroxide [Mg (O
H) ₂ ], the water content is 1% or less, especially 2%
It is preferable to use 000 ppm or less of alcohol. Further, in order to obtain a solid product (a) having a better morphology, it is preferable that the water content is as small as possible.

The type of halogen is not particularly limited, but chlorine, bromine or iodine, particularly iodine, is preferably used. The state, shape, particle size, and the like are not particularly limited, and may be arbitrary. For example, they can be used in the form of a solution in an alcohol-based solvent (for example, ethanol).
The amount of alcohol is not limited, but is preferably 2 to 100 mol, and particularly preferably 5 to 50 mol, per 1 mol of metallic magnesium. If the amount of alcohol is too large, the yield of the solid product (a) having a good morphology may be reduced. If the amount is too small, stirring in the reaction tank may not be performed smoothly. However, it is not limited to the molar ratio. The amount of halogen used is 0.00
It is at least 01 gram atom, preferably at least 0.0005 gram atom, more preferably at least 0.001 gram atom. When the amount is less than 0.0001 g atom, there is not much difference from the amount of the halogen used as the reaction initiator, and when the obtained solid product (a) is used without pulverization, the supported amount, the activity, the stereoregularity, and the formed polymer In all of the morphology and the like. Therefore, the pulverization of the solid product (a) is indispensable. The upper limit of the amount of halogen used is not particularly limited, but is generally 0.06.
It is chosen in the range of less than gram atoms. The particle size of the solid product (a) can be freely controlled by appropriately selecting the amount of halogen used.

The reaction between the magnesium metal, the alcohol and the halogen can itself be carried out in the same manner as in a known method. That is, a method of obtaining a solid product (a) by reacting metallic magnesium, an alcohol, and a halogen under reflux (about 79 ° C.) until generation of hydrogen gas is no longer observed (generally, about 20 to 30 hours). It is. In particular,
For example, when using iodine as a halogen, metal magnesium, a method of charging solid iodine in alcohol, and then heating and refluxing, a method of heating and refluxing after dropping an alcohol solution of iodine in metal magnesium and alcohol, and a method of refluxing A method of dropping an alcohol solution of iodine while heating a metal magnesium or alcohol solution. Both methods are preferably performed in an inert gas (for example, nitrogen gas, argon gas) atmosphere and optionally using an inert organic solvent (for example, saturated hydrocarbon such as n-hexane). Regarding the charging of the metal magnesium, the alcohol, and the halogen, it is not necessary to charge all of them to the reaction tank from the beginning, and they may be divided and charged. A particularly preferred form is a method in which the alcohol is charged in its entirety from the beginning, and the magnesium metal is divided and charged several times. In this case, a temporary large amount of hydrogen gas can be prevented, which is very desirable from the viewpoint of safety. Also, the size of the reaction tank can be reduced.
Further, it is possible to prevent entrainment of alcohol or halogen caused by temporary mass generation of hydrogen gas. The number of divisions may be determined in consideration of the scale of the reaction tank, and is not particularly limited, but usually 5 to 10 times is preferable in view of the complexity of the operation.

Further, it goes without saying that the reaction itself may be either a batch type or a continuous type. Further, as a variant, a small amount of metallic magnesium is first introduced into the alcohol which has been initially introduced in its entirety, and the product formed by the reaction is produced. It is also possible to repeat the operation of separating and removing the material in another tank and then adding a small amount of metallic magnesium again. When the solid product thus obtained is used in the next synthesis of a solid catalyst composition, a dried product may be used, or a product washed with an inert solvent such as heptane after filtration may be used. In any case, the obtained solid product (a) can be used in the following steps without pulverization or classification operation for adjusting the particle size distribution.

(B) Titanium Compound In the present invention, any titanium compound can be used as the titanium compound (b). These titanium compounds, for example, the general formula _{^{(I) TiX 1 n (OR}} 1) in _4-n ... (I) (wherein, X ¹ is a halogen atom, especially a chlorine atom, R ¹
Is a hydrocarbon group having 1 to 10 carbon atoms, particularly a linear or branched alkyl group, and when a plurality of groups R ¹ are present, they may be the same or different from each other. n is 0
4 is an integer. ).
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 (OC ₄ H ₉ ) ₂ , TiCl ₂ (OiC ₃ H ₇ ) ₂ , T
iCl _{4 and the} like can be mentioned.

(C) Electron-donating Compound In the solid catalyst component (A) of the present invention, any electron-donating compound (c) can be used, if necessary. These electron donating compounds (c) are usually organic compounds containing oxygen, nitrogen, phosphorus or sulfur. Specifically, amines, amides, ketones, nitriles, phosphines, phosphylamides, esters, ethers, thioethers, alcohols, thioesters,
Acid anhydrides, acid halides, aldehydes, organic acids,
An organosilicon compound having a Si-OC bond may be mentioned, and more specifically, the following compounds may be mentioned.

Aromatic carboxylic acids such as benzoic acid, p
-Oxybenzoic acid; acid anhydrides such as succinic anhydride,
Benzoic anhydride, p-toluic anhydride; Carbon index 3-1
5 ketones, for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, benzophenone, benzoquinone; aldehydes having 2 to 15 carbon atoms, for example, acetaldehyde, propionaldehyde, octylaldehyde, benzaldehyde, naphthaldehyde; 2 carbon atoms ~ 18 esters, for example,
Methyl formate, ethyl formate, methyl acetate, ethyl acetate, vinyl acetate, propyl acetate, octyl acetate, cyclohexyl acetate, ethyl propionate, methyl butyrate, ethyl butyrate, ethyl valerate, methyl chloroacetate, ethyl dichloroacetate, methyl methacrylate, Ethyl crotonate, ethyl pivalate, dimethyl maleate, ethyl cyclohexanecarboxylate, methyl benzoate, ethyl benzoate, propyl benzoate, butyl benzoate, octyl benzoate, cyclohexyl benzoate, phenyl benzoate, benzyl benzoate, toluyl Methyl acrylate, ethyl toluate, amyl toluate, ethyl ethyl benzoate, methyl anisate,
Ethyl anisate, ethyl ethoxybenzoate, ethyl p-butoxybenzoate, ethyl o-chlorobenzoate, ethyl naphthoate, γ-butyrolactone, δ-valerolactone, coumarin, phthalide, ethylene carbonate; mono and aromatic dicarboxylic acids Diesters such as monoesters and diesters of phthalic acid are preferred, for example, monomethyl phthalate, dimethyl phthalate, monomethyl terephthalate, dimethyl terephthalate, monoethyl phthalate, diethyl phthalate, monoethyl terephthalate,
Diethyl terephthalate, monopropyl phthalate, dipropyl phthalate, monopropyl terephthalate, dipropyl terephthalate, monobutyl phthalate, dibutyl phthalate, monobutyl terephthalate, dibutyl terephthalate, monoisobutyl phthalate, diisobutyl phthalate, monoamyl phthalate, diamyl phthalate, Monoisoamyl phthalate, diisoamyl phthalate, ethyl butyl phthalate, ethyl isobutyl phthalate, ethyl propyl phthalate,

Acid halides having 2 to 20 carbon atoms,
The acid moiety (acyl group moiety) of the acid halide may be an aliphatic (including an alicyclic or other ring-containing) monobasic, dibasic, or tribasic group having about 2 to 20 carbon atoms. A monovalent to trivalent acyl acid obtained by extracting each hydroxyl group from an acid, or an aromatic (including alkaryl or aralkyl type) monobasic group having about 7 to 20 carbon atoms;
A monovalent to trivalent acyl group obtained by extracting each hydroxyl group from a dibasic or tribasic acid is preferred. Further, as the halogen atom in the acid halide, a chlorine atom, a bromine atom and the like are preferable, and a chlorine atom is particularly preferable. In the present invention, acid halides that can be suitably used include, for example, acetyl chloride, acetyl bromide, propionyl chloride, butyryl chloride, isobutyryl chloride, 2-methylpropionyl chloride, valeryl chloride, isovaleryl Chloride, hexanoyl chloride, methylhexanoyl chloride, 2
-Ethylhexanoyl chloride, octanoyl chloride, decanoyl chloride, undecanoyl chloride, hexadecanoyl chloride, octadecanoyl chloride,
Hensyl carbonyl chloride, dichlorohexane carbonyl chloride, malonyl dichloride, succinyl dichloride, pentanedioyl dichloride, hexane dioil dichloride, dichlorohexane dicarbonyl dichloride, benzoyl chloride, benzoyl bromide, methyl benzoyl chloride, phthaloyl chloride, isophthaloyl chloride , Terephthaloyl chloride, benzene-1,2,2
4-tricarbonyl trichloride and the like can be mentioned. Among these, phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride and the like are particularly preferable, and phthaloyl chloride is particularly preferable. These acid halides may be used alone or in a combination of two or more.

Ethers having 2 to 20 carbon atoms, for example, methyl ether, ethyl ether, isopropyl ether, n-butyl ether, amyl ether, tetrahydrofuran, anisole, diphenyl ether, ethylene glycol butyl ether; acid amides such as acetate amide, benzoate Acid amide, toluic acid amide; amines such as tributylamine, N, N′-dimethylpiperazine, tribenzylamine, aniline, pyridine,
Pyrroline, tetramethylethylenediamine; nitriles, for example, acetonitrile, benzonitrile, tolunitrile; tetramethylurea, nitrobenzene, lithium butyrate; organosilicon compounds having a Si—O—C bond, for example, trimethylmethoxysilane, trimethylethoxysilane, Dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, methylphenyldimethoxysilane, diphenyldiethoxysilane, phenyltrimethoxysilane, γ-chloropropyltotrimethoxysilane, methyltriethoxysilane, ethyltriethoxysilane, vinyltriethoxysilane ,
Butyltriethoxysilane, phenyltriethoxysilane, γ-aminopropyltriethoxysilane, chlorotriethoxysilane, ethyltriisopropoxysilane,
Vinyl tributoxy silane, ethyl silicate, butyl silicate, trimethylphenoxy silane, methyl triaryloxy silane, vinyl tris (β-methoxyethoxy) silane, vinyl triacetoxy silane, dimethyl tetraethoxy disiloxane and the like can be mentioned. Of these, preferred are esters, ethers, ketones, acid anhydrides and the like.

Method for Preparing Solid Catalyst Component (A) The solid catalyst component (A) comprises a magnesium compound (a) and
It can be prepared by a known method using the titanium compound (b) and, if necessary, the electron donating compound (c).
For example, it is preferable that the magnesium compound (a) is brought into contact with the electron donating compound (c) and then brought into contact with the titanium compound (b). The conditions for bringing the electron donating compound (c) into contact with the magnesium compound (a) are not particularly limited, and may be appropriately determined according to various circumstances. Usually, magnesium compound (a)
Electron-donating compound (c) 0.01 to 10 with respect to 1 mol
Mol, preferably 0.05 to 5 mol, and
At 5 ° C. for 5 minutes to 10 hours, preferably 30 to 150 hours.
The contact reaction may be performed at 30 ° C. for 30 minutes to 3 hours. In addition, an inert hydrocarbon such as pentane, hexane, heptane or octane can be added as a solvent to this reaction system. The conditions for contacting the titanium compound (b) with the magnesium compound (a) or the contact product thereof with the electron-donating compound (c) are not particularly limited. 1 to 50 moles, preferably 2 moles, of the titanium compound (b) is used per mole.
加 え 20 mol, added at 0２００200 ° C. for 5 minutes〜１０10
The reaction is carried out at a temperature of preferably 30 to 150 ° C. for 30 minutes to 5 hours. The contact with the titanium compound (b) is carried out by using a liquid titanium compound (for example, titanium tetrachloride) by itself and other titanium compounds by using any inert hydrocarbon solvent (for example, hexane, heptane, kerosene). It can be performed in a dissolved state. Also, a magnesium compound (a)
Before the above-mentioned contact with the titanium compound (b) and, if necessary, the electron-donating compound (c), for example, a halogenated hydrocarbon, a halogen-containing silicon compound, a halogen gas, hydrogen chloride, hydrogen iodide, etc. Can be brought into contact with the magnesium compound (a). After the completion of the reaction, the product is preferably washed with an inert hydrocarbon (for example, n-hexane or n-heptane).

[0018] (B) The organoaluminum compound organic Arumiumu compound (B), is not particularly limited, in the following general formula _{^{(II) AlR 2 m X 2}} 3-m ... (II) ( wherein, R ² is carbon A compound represented by the formula: an alkyl group, a cycloalkyl group, or an aryl group having 1 to 10 atoms, m is an integer of 1 to 3, and X ² is a halogen atom such as a chlorine atom or a bromine atom. Can be Specifically, a trialkylaluminum compound such as trimethylaluminum, triethylaluminum, triisopropylaluminum, triisobutylaluminum or trioctylaluminum; or a dialkylaluminum monohalide compound such as diethylaluminum monochloride or dipropylaluminum monochloride Or dioctyl aluminum monochloride and the like can be mentioned.

(C) Electron-donating Compound In the production method of the present invention, an electron-donating compound (C) can be used in combination, if necessary. In this case, the solid catalyst component (A) may be used as the electron donating compound (C).
The same compounds as those of the electron donating compound (c) used in the preparation of can be used. At this time, the electron donating compound (C) may be the same as or different from the electron donating compound (c) used in the preparation of the solid catalyst component (A). The preferred electron donating compound (C) is a silane compound having a Si-OC bond, particularly a compound represented by the following formula (III). R ³ _p Si (OR ⁴ ) _4-p (III) (wherein, R ³ is a linear or branched hydrocarbon residue;
A compound selected from an aromatic hydrocarbon residue or a cyclic saturated hydrocarbon residue, and when p ≧ 2, a combination of any of the above compounds may be used. R ⁴ is a linear or branched hydrocarbon residue. (p is 0 ≦ p ≦ 3) As the compound of the formula (III), specifically, tert-butylcyclohexyldimethoxysilane, methylcyclohexyldimethoxysilane, di-tert-butyldimethoxysilane, dicyclohexyldimethoxysilane, diphenyldimethoxysilane Dimethyldiethoxysilane, trimethylethoxysilane, methylphenyldimethoxysilane, and the like.

In the present invention, the above-mentioned highly stereoregular catalyst is used, and as shown in FIG. 1, after a propylene crystalline homopolymer or copolymer is produced in the previous polymerization step in a homopolymerization tank. Upon random copolymerization of propylene and other α-olefins in the presence of the polymer or copolymer in a subsequent polymerization step in a random copolymerization tank, cooling circulation of monomers in the latter random copolymerization system An electron donating compound is supplied to the channel.

As the electron donating compound to be supplied to the circulation channel, the electron donating compound (c) used in the preparation of the solid catalyst component (A) (however, aromatic carboxylic acid ester, ROH (excluding an alcohol represented by ROH (wherein R represents a hydrocarbon group having 5 to 20 carbon atoms)) and an electron-donating compound used for preparing the catalyst (provided that aromatic carboxylic acid ester, General formula ROH
(Wherein, R represents a hydrocarbon group having 5 to 20 carbon atoms). ) Can be used. At this time, the electron donating compound supplied to the circulation channel may be the same as or different from the electron donating compound (c) or (C).

The method of supplying the electron donating compound to the circulation channel is not particularly limited. For example, a method of directly supplying the electron donating compound to the circulation channel may be employed. A method of diluting and supplying an inert solvent is particularly preferable. The addition amount of the electron donating compound is 0.0 to 1 mol of the organoaluminum compound.
It is 1 to 1.7 mol, preferably 0.1 to 1.5 mol. If the amount is less than 0.01 mol, the effect of suppressing gel and fish eyes may not be sufficient, and 1.7 mo may be obtained.
If it exceeds 1, the activity of the random polymerization tank may be reduced.

In the present invention, a crystalline polymer or copolymer of propylene is produced in the preceding step, but in this step, the polymerization may be carried out in two or more steps. In addition, prior to full-scale polymerization, for the purpose of improving catalytic activity, improving bulk density, improving fluidity, etc.
A prepolymerization treatment in which the catalyst is brought into contact with a small amount of propylene in advance may be performed. As an example of the prepolymerization treatment, for example, the treatment shown in JP-B-57-45244 can be exemplified. The pre-stage polymerization can be carried out in the liquid or gas phase in the presence or absence of an inert solvent. A suitable amount of each catalyst component can be appropriately selected depending on its type and the like. In the former stage polymerization, a crystalline polymer or copolymer of propylene is produced in order to obtain a highly rigid block copolymer.
As the copolymerization component for producing the copolymer, α-olefins other than propylene, for example, ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-octene Those having 2 to 10 carbon atoms such as decene can be exemplified. It is preferable to produce the polymer or copolymer having an intrinsic viscosity [η] measured in decalin at 135 ° C. of, for example, about 1 to about 10 dl / g, particularly about 1 to about 5 dl / g,
For this purpose, a molecular weight modifier, preferably hydrogen, may be allowed to coexist in the polymerization system. The polymerization temperature can be appropriately selected and is, for example, about 50 to about 100 ° C, preferably about 60 ° C.
To about 90 ° C. The polymerization pressure can also be appropriately selected, for example, a polymerization pressure of about 1 to about 200 kg / cm ² G, preferably about 1 to about 100 kg / cm ² G. When performing liquid phase polymerization, propylene may be used for the liquid medium, or an inert solvent may be used for the liquid medium. Examples of such inert solvents include, for example, propane, butane, pentane, hexane, heptane, octane, decane, kerosene and the like.

In the present invention, in the subsequent polymerization step, random copolymerization of propylene with another α-olefin is carried out in the presence of the catalyst-containing propylene crystalline polymer or copolymer obtained in the previous step. This random copolymerization is usually carried out subsequent to the previous polymerization step for producing a crystalline polymer or copolymer of propylene. Random copolymerization can also be performed in the liquid or gas phase. In particular, if gas phase polymerization is employed, the copolymer is entirely incorporated into the block copolymer, so that the yield with respect to the consumed olefin is high, which is industrially advantageous. Examples of other α-olefins used for random copolymerization include ethylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, and 1-decene.
Preferably ethylene, or ethylene and C4 -C5 α-
Combination with olefin. The copolymerization ratio of propylene to other α-olefin is from 10/90 to 90 /
10, preferably 20/80 to 80/20.

[0025]

The present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention. In the following examples, the following reagents were used. Ethanol: Special grade reagent manufactured by Wako Pure Chemical Industries, Ltd. Iodine: Wako Pure Chemical Industries, Ltd., reagent grade. Metallic magnesium: Granular (average particle size 350 μm). Example 1 (1) Preparation of magnesium compound (a) Glass reactor with stirrer (internal volume: about 12 liters)
Is sufficiently replaced with nitrogen gas, about 4860 g of ethanol,
32 g of iodine and 320 g of metallic magnesium are charged,
The reaction was carried out under heating under reflux conditions with stirring until no hydrogen gas was generated from the system, to obtain a solid reaction product. The reaction solution containing the solid product was dried under reduced pressure to obtain a magnesium compound (solid product) (a). (2) Preparation of solid catalyst component (A) The magnesium compound (a) was placed in a three-neck glass flask (internal volume: 5 liters) sufficiently purged with nitrogen gas.
160 g (unground), purified heptane 800
ml, silicon tetrachloride 24 ml, and diethyl phthalate 2
3 ml was added. While maintaining the inside of the system at 90 ° C., 770 ml of titanium tetrachloride was added with stirring and reacted at 110 ° C. for 2 hours, the solid component was separated and washed with purified heptane at 80 ° C. Further, 1220 ml of titanium tetrachloride was added, and 1
After reacting at 10 ° C. for 2 hours, it was sufficiently washed with purified heptane to obtain a solid catalyst component (A).

(3) Polymerization / Pretreatment 230 liters of n-heptane was charged into a reaction vessel having a stirring blade having an inner volume of 500 liters, and the solid catalyst component was added at 25K.
g, triethylaluminum, 0.6 mol / g based on Ti atoms in the solid catalyst component, and diphenyldimethoxysilane, 0.4 mol / g based on Ti atoms in the solid catalyst component.
After supplying at a rate of 1 g atom, propylene was introduced until the propylene partial pressure reached 0.3 kg / cm ² G, and 55 ° C.
For 4 hours. After the completion of the reaction, the solid catalyst component was replaced with n-
After washing several times with heptane, carbon dioxide was supplied and the mixture was stirred for 24 hours. As the first stage of the main polymerization, in the polymerization tank (homopolymerization tank) having an inner volume of 200 liters with stirring blades, the treated solid catalyst component was converted to 3 atoms / Hr in terms of Ti atoms in the component, and triethyl aluminum was converted to 600 mmol / hr. With Hr, diphenyldimethoxysilane was supplied at 15 mmol / Hr, respectively, at a polymerization temperature of 70 ° C. and a propylene pressure of 28 kg / cm ^2.
G was reacted. At this time, it was adjusted with hydrogen so as to have a predetermined molecular weight. Next, the powder is continuously extracted from the homopolymerization tank and transferred to a random copolymerization tank. In the random copolymerization tank, propylene and ethylene were supplied at a polymerization temperature of 55 ° C. as a subsequent stage to perform random copolymerization. At this time, so that the predetermined ethylene content,
The supply ratio of propylene to ethylene was adjusted. Further, at the time of random copolymerization, ethanol was supplied to the monomer cooling circulation system at 700 mmol / Hr. This supply amount was 1.17 mol / mol as a molar ratio of ethanol / organoaluminum compound. The powder continuously extracted from the random copolymerization tank was granulated and evaluated. Table 1 shows the results.

Example 2 Ethanol as an electron donating compound to the circulation channel was 12
The same operation as in Example 1 was performed except that the supply was performed at 0 mmol / Hr. The supply amount is 0.2 mol / mol as a molar ratio of ethanol / organoaluminum compound.
Table 1 shows the results. Example 3 Example 3 was carried out in the same manner as in Example 1 except that dimethoxybenzene was supplied at 360 mmol / Hr as an electron donating compound to the circulation channel. This supply amount was 0.6 mol as a dimethoxybenzene / aerated aluminum compound molar ratio.
1 / mol. Table 1 shows the results. Example 4 Example 4 was repeated, except that diphenyldimethoxysilane was supplied at 700 mmol / Hr as an electron-donating compound to the circulation channel. This supply amount is 1.17 mol / mol as a diphenyldimethoxysilane / organoaluminum compound molar ratio. Table 1 shows the results. Comparative Example 1 The same operation as in Example 1 was performed, except that the electron donating compound was not supplied to the circulation channel. Table 1 shows the results.

MI (1) in Table 1 is the melt index of the product in the preceding polymerization step, MI
(2) is the melt index of the propylene block copolymer produced in the latter stage. Another physical property is the physical property of the propylene block copolymer produced in the latter stage. Each physical property in Table 1 was measured by the following method. Fisheye: A film having a thickness of 30 μm was formed using a cast molding machine having a screw diameter of 20 mm.
Fish eyes per cm ² were visually observed. Tensile modulus: Measured according to JIK K6738. Izod impact strength: Measured according to JIS K6738. However, the measurement temperature was −20 ° C.

[0029]

[Table 1]

[0030]

As described below, according to the production method of the present invention, a propylene block copolymer having excellent mechanical properties such as rigidity and impact strength and improved appearance of a product can be produced with high productivity. be able to. In this case, the trouble of clogging of the circulation system due to the polymer generated by the catalyst particles splashed into the circulation system can be satisfactorily prevented.

[0031]

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of the production method of the present invention.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08F 297/08 C08F 4/654

Claims (1)

(57) [Claims] 1. Use of a high stereoregularity catalyst obtained by using a solid catalyst component containing at least (A) magnesium, titanium and halogen and (B) an organoaluminum compound, and the propylene crystallinity of propylene alone in the preceding polymerization step A method for producing a propylene block copolymer, comprising producing a polymer or copolymer, and then randomly copolymerizing propylene and another α-olefin in the presence of the polymer or copolymer in a subsequent polymerization step. In the latter polymerization step, the unreacted monomer is recycled and reused through the circulation channel,
An electron-donating compound (however, an aromatic carboxylic acid ester and a general formula ROH
(Wherein, R represents a hydrocarbon group having 5 to 20 carbon atoms). ). A method for producing a propylene block copolymer, characterized in that: