Method for producing olefin polymer

Abstract

To provide a method for producing an olefin polymer that enables long-term continuous operation by suppressing the clogging of catalyst supply lines and the formation of coarse particles due to adhesion of polymer particles to each other.SOLUTION: A method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst comprising a solid catalyst component (X) comprises bringing a poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) represented by the general formula (I), HO-(C3H6O)a-(C2H4O)b-(C3H6O)c-H, into contact with the solid catalyst component (X), and then supplying the mixture to a polymerization vessel. In the general formula (I), a and c are each independently an integer from 1 to 60, and b is an integer from 1 to 29, where a+c=2 to 120 and a+b+c≥3 are satisfied.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing an olefin polymer, particularly a propylene homopolymer or a copolymer of propylene and another α-olefin.

Background Art

[0002] In the production of olefin polymers such as polypropylene or copolymers of propylene and other α-olefins, Ziegler-Natta catalysts with high activity and high stereoregularity have been developed. As a result, the production amount of olefin polymers per catalyst has increased dramatically, and the regularity of olefin polymers has been improved. As a result, it has become possible to reduce the metal components such as catalyst components present in the olefin polymer and to reduce the amorphous polypropylene component. For this reason, a method for producing an olefin polymer by a gas-phase polymerization method that does not require a step of removing metal components and amorphous polypropylene components has attracted attention. The method for producing an olefin polymer by the gas-phase polymerization method has features such as not requiring a solvent recovery or purification step, being easy to recover monomers or dry polymers, and being able to respond to product diversification, as compared with conventional solution polymerization, slurry polymerization, or bulk polymerization.

[0003] In particular, the gas-phase polymerization method using a polymerization tank equipped with stirring blades has the advantage of being able to compact the equipment because the latent heat of vaporization of liquefied propylene can be utilized. The method for producing an olefin polymer by the gas-phase polymerization method using a polymerization tank equipped with stirring blades is a very excellent process. However, in the gas-phase polymerization method, since the inside of the polymerization tank is divided into a polymer powder part and a gas phase part, the fluidity, stirring, and uniformity of the entire tank are not sufficient. Therefore, compared with the solution method or the slurry method, the stirring effect and the homogenizing effect may not be sufficient. In particular, in the case of gas-phase polymerization using a polymerization tank equipped with stirring blades, the operating state of the polymerization apparatus often becomes unstable due to the generation of coarse particles due to the fusion of polymer particles with each other, poor stirring, etc., and the stirring power also tends to increase. Among them, in the case of a random copolymer of propylene and other α-olefins such as ethylene, since the polymer melting point decreases, coarse particles and lumps in which polymer particles are fused are likely to occur. As a result, there is a problem that stable long-term continuous operation is difficult because of clogging at the extraction part of the olefin polymer powder, or troubles such as trips due to the biting of coarse particles or lumps into the rotary valve.

[0004] The generation of such coarse particles and lumps not only makes it difficult to achieve stable long-term continuous production, but also causes problems such as non-uniformity of the polymer composition and deterioration of the quality of the final molded product.

[0005] For this reason, in the method for producing an olefin polymer using an olefin polymerization catalyst, even when using a polymerization tank equipped with stirring blades, a method has been proposed that enables stable long-term continuous production of the olefin polymer and suppresses deterioration of the quality of the final molded product. For example, in Patent Document 1, in the method for producing an olefin polymer by continuous gas-phase polymerization using an olefin polymerization catalyst, a continuous gas-phase polymerization apparatus having a polymerization tank equipped with stirring blades and a catalyst pretreatment section is used, and in the catalyst pretreatment section, an olefin polymerization catalyst (X) and a general formula (I): HO-(CH2CH2O) a -{CH2CH(CH3)O} b -(CH2CH2O) cAfter contacting and mixing with a polyoxyethylene polyoxypropylene glycol compound (G) represented by H, the mixture is supplied to the polymerization tank to polymerize an olefin monomer, and a method for producing an olefin polymer is disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] In gas-phase polymerization using a polymerization tank equipped with a stirring blade, compared with gas-phase polymerization using a fluidized-bed type polymerization tank not equipped with a stirring blade, catalysts that are prone to aggregation or catalysts with a large particle size are often used, and blockage of the catalyst supply line is likely to occur, or generation of coarse particles due to adhesion of polymer particles may occur. If a catalyst cannot be stably supplied, long-term continuous operation becomes difficult. In addition, when there are many coarse particles, the temperature in the polymerization tank becomes non-uniform, the control of the polymerization temperature becomes unstable, and the stirring resistance increases, etc., and the operating state of the polymerization apparatus often becomes unstable. Thus, even in gas-phase polymerization using a polymerization tank equipped with a stirring blade, development of a method for suppressing blockage of the catalyst supply line, suppressing generation of coarse particles and lumps due to adhesion of polymer particles, and improving the operating stability of the polymerization apparatus has been demanded. However, Patent Document 1 has no problem of blockage of the catalyst supply line, and according to the polyoxyethylene polyoxypropylene glycol compound represented by HO-(CH2CH2O) a -{CH2CH(CH3)O} b -(CH2CH2O) c H disclosed in Patent Document 1, since it is hardly soluble in a hydrocarbon solvent, the effect of suppressing blockage of the catalyst supply line is insufficient. In addition, when suppressing the blockage of the catalyst supply line and suppressing the generation of coarse particles and lumps due to the adhesion of polymer particles, it is also required not to affect polymerization performance such as hydrogen responsiveness and polymerization activity, and the physical properties of the polymer.

[0008] In view of such a prior art situation, the present invention provides a method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component, without affecting polymerization performance such as hydrogen responsiveness and polymerization activity and the physical properties of the polymer, suppressing the blockage of the catalyst supply line, and suppressing the generation of coarse particles due to the adhesion of polymer particles, thereby enabling long-term continuous operation. [Means for Solving the Problems]

[0009] The present inventors have found that, in the production of an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component, by contacting a specific poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) (hereinafter sometimes referred to as "PPG-PEG-PPG block copolymer (G)") with the solid catalyst component (X) and then supplying it to the polymerization tank, it is possible to suppress the blockage of the catalyst supply line and suppress the generation of coarse particles due to the adhesion of polymer particles without affecting polymerization performance such as hydrogen responsiveness and polymerization activity and the physical properties of the polymer, thereby enabling long-term continuous operation. That is, the present invention relates to the following [1] to [5].

[0010] [1] In a method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component (X), A method for producing an olefin polymer, characterized in that a poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) represented by the following general formula (I) is contacted with the solid catalyst component (X) and then supplied to the polymerization tank. HO-(C3H6O) a-(C2H4O) b -(C3H6O) c -H···(I) [In general formula (I), a and c are each independently an integer of 1 to 60, b is an integer of 1 to 29, and a + c = 2 to 120, and a + b + c ≥ 3 is satisfied.] [2] A method for producing an olefin polymer according to [1] above, characterized in that after contacting the poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) represented by the general formula (I) with the solid catalyst component (X) in a hydrocarbon solvent, the obtained catalyst slurry is supplied to a polymerization tank. [3] A method for producing an olefin polymer according to [1] or [2] above, characterized in that the contact is carried out in a catalyst storage tank or a catalyst supply line. [4] A method for producing an olefin polymer according to any one of [1] to [3] above, characterized in that the contact amount of the block copolymer (G) is 0.5% by mass to 20% by mass with respect to the solid catalyst component (X). [5] A method for producing an olefin polymer according to any one of [1] to [4] above, characterized in that the olefin polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and α-olefins having 4 or more carbon atoms. [Advantages of the Invention]

[0011] In the production of an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component, the method for producing an olefin polymer of the present invention can suppress clogging of the catalyst supply line and generation of coarse particles due to adhesion of polymer particles without affecting polymerization performance such as hydrogen responsiveness and polymerization activity and physical properties of the polymer. As a result, the method for producing an olefin polymer of the present invention can suppress long-term stable supply of the catalyst and destabilization of the operating state due to coarse particles, enable long-term continuous operation, and suppress deterioration of the quality of the final molded product. [Embodiments for Carrying Out the Invention]

[0012] The method for producing an olefin polymer of the present invention is a method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component (X), characterized in that a poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) represented by the following general formula (I) is brought into contact with the solid catalyst component (X) and then supplied to a polymerization tank. HO-(C3H6O) a -(C2H4O) b -(C3H6O) c -H···(I) [In the general formula (I), a and c are each independently an integer of 1 to 60, b is an integer of 1 to 29, and a + c = 2 to 120, satisfying a + b + c ≥ 3.]

[0013] In the method for producing an olefin polymer of the present invention, in a method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component (X), the specific poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) is brought into contact with the solid catalyst component (X) and then supplied to a polymerization tank. Thereby, the dispersibility of the catalyst itself is improved, aggregation is suppressed, blockage of the catalyst supply line is suppressed, and the dispersion of the catalyst in the polymerization tank is made uniform, so that the generation of coarse particles due to adhesion of polymer particles can be suppressed, enabling long-term continuous operation. Further, according to the method of bringing the specific poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) into contact with the solid catalyst component (X) and then supplying it to the polymerization tank, it does not affect polymerization performance such as hydrogen responsiveness and polymerization activity and the physical properties of the polymer. The present invention can be suitably employed in the production of a propylene homopolymer or a random copolymer of propylene and another α-olefin. Particularly preferably, it can be employed in the production of a random copolymer or a block copolymer of propylene and another α-olefin.

[0014] Hereinafter, the method for producing the olefin polymer of the present invention will be described in detail item by item. In this specification, "~" indicating a numerical range is used to mean that the numerical values described before and after it are included as the lower limit value and the upper limit value.

[0015] 1. Olefin polymerization catalyst The olefin polymerization catalyst used in the present invention is not particularly limited as long as it contains a solid catalyst component (X), and a known olefin polymerization catalyst is used. The olefin polymerization catalyst may contain a co-catalyst or the like in the solid catalyst component (X). The olefin polymerization catalyst used in the present invention can be appropriately selected and used, for example, from Ziegler catalysts and metallocene catalysts.

[0016] Examples of the Ziegler catalyst include those obtained by combining an organoaluminum compound and an electron donor as an external donor with a solid catalyst component (X) that contains, for example, a titanium atom, a magnesium atom, and a halogen atom, and further contains an electron donor if necessary. Examples of the Ziegler-Natta catalyst include those obtained by reducing titanium trichloride or a titanium trichloride composition obtained by reduction with an organoaluminum or the like as a titanium compound with an electron-donating compound and further activating it, and so-called supported catalysts obtained by supporting titanium tetrachloride on a carrier such as magnesium chloride.

[0017] Examples of the metallocene catalyst include those obtained by combining (a) a metallocene complex, (b) a compound that reacts with the metallocene complex to form an ion pair, or a solid catalyst component (X) supported on an ion-exchangeable layered silicate with an alumoxane or an organoaluminum compound.

[0018] Examples of the (a) metallocene complex in the metallocene catalyst include compounds represented by the following general formulas (1) to (4).

[0019] [Chemical formula] In the above general formulas (1) to (4), A and A' each represent a conjugated five-membered ring ligand which may have a substituent (A and A' may be the same or different within the same compound), Q represents a bonding group that crosslinks two conjugated five-membered ring ligands at an arbitrary position, Z represents a ligand containing a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom or a sulfur atom, a hydrogen atom, a halogen atom, or a hydrocarbon group, and Z' represents a ligand containing a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom or a sulfur atom, or a hydrocarbon group. Q' represents a bonding group that crosslinks an arbitrary position of the conjugated five-membered ring ligand and Z, M represents a metal atom selected from Group 4 of the periodic table, and X and Y each represent a hydrogen atom, a halogen atom, a hydrocarbon group, an alkoxy group, an amino group, a phosphorus atom-containing hydrocarbon group or a silicon atom-containing hydrocarbon group (X and Y may be the same or different within the same compound).

[0020] Examples of the conjugated five-membered ring ligands of A and A' include conjugated five-membered ring ligands derived from cyclopentadiene, indene, tetrahydroindene, fluorene, azulene, and tetrahydroazulene. These may be unsubstituted or substituted. Among these, particularly preferred are substituted or unsubstituted indenyl groups or azulenyl groups.

[0021] Examples of the substituent on the conjugated five-membered ring ligand include a hydrocarbon group having 1 to 40 carbon atoms, preferably 1 to 30 carbon atoms, a hydrocarbon group having 1 to 30 carbon atoms substituted with a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom, a halogen atom such as a fluorine atom, a chlorine atom, or a bromine atom, an alkoxy group having 1 to 12 carbon atoms, for example, a silicon atom-containing hydrocarbon group represented by -Si(R 1 )(R 2 )(R 3 ), a phosphorus atom-containing hydrocarbon group represented by -P(R 1 )(R 2 ), or a boron-containing hydrocarbon group represented by -B(R 1 )(R 2 ). When there are a plurality of these substituents, each substituent may be the same or different. The above R 1 , R 2 , R 3 may be the same or different and each represents an alkyl group having 1 to 24 carbon atoms, preferably 1 to 18 carbon atoms. Further, the substituent on the conjugated five-membered ring ligand may have at least one element of Groups 15 and 16 of the periodic table (i.e., hetero element). Preferred examples of such a substituent include monocyclic or polycyclic substituents containing at least one hetero atom selected from the group consisting of an oxygen atom, a sulfur atom, a nitrogen atom, and a phosphorus atom in a 5- or 6-membered ring. More preferably, it is a substituent derived from an optionally substituted heteroaromatic compound, and particularly preferably, an optionally substituted furyl group and an optionally substituted thienyl group. In the case of a compound having a bridging group represented by the general formula (2) or (4), these substituents are not particularly limited, but are preferably located at the α-position (based on the bonding site with the bridging group) on the conjugated five-membered ring ligand.

[0022] Q represents a bonding group that bridges between two conjugated five-membered ring ligands at an arbitrary position, and Q' represents a bonding group that bridges an arbitrary position of the conjugated five-membered ring ligand and the group represented by Z. Specific examples of Q and Q' include the following groups. (a) Alkylene groups such as methylene group, ethylene group, isopropylene group, dimethylmethylene group, phenylmethylmethylene group, diphenylmethylene group, cyclobutylene group, cyclohexylene group (b) Silylene groups such as dimethylsilylene group, diethylsilylene group, dipropylsilylene group, diphenylsilylene group, methylethylsilylene group, methylphenylsilylene group, methyl-t-butylsilylene group, disilylene group, tetramethyldisilylene group, silacyclobutylene group (c) Substituted germylene group, substituted phosphorus group, substituted amino group, substituted boron group or substituted alylen group substituted with a hydrocarbon group

[0023] Furthermore, specifically, they are groups represented by (CH3)2Ge, (C6H5)2Ge, (CH3)P, (C6H5)P, (C4H9)N, (C6H5)N, (C4H9)B, (C6H5)B, (C6H5)Al, (C6H5O)Al, etc. Preferred ones are alkylene groups or silylene groups.

[0024] Also, M represents a metal atom, and particularly represents a transition metal atom selected from Group 4 of the periodic table. Examples of M include titanium, zirconium, hafnium, etc. Particularly, zirconium and hafnium are preferred. Furthermore, Z represents a ligand containing a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom or a sulfur atom, a hydrogen atom, a halogen atom or a hydrocarbon group, and Z’ represents a ligand containing a nitrogen atom, an oxygen atom, a silicon atom, a phosphorus atom or a sulfur atom, or a hydrocarbon group. Preferred specific examples of Z and Z’ include hydrocarbon groups containing an oxygen atom with 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms, hydrocarbon groups containing a sulfur atom with 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms, hydrocarbon groups containing a silicon atom with 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms, hydrocarbon groups containing a nitrogen atom with 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms, hydrocarbon groups containing a phosphorus atom with 1 to 40 carbon atoms, preferably 1 to 18 carbon atoms, and hydrocarbon groups with 1 to 20 carbon atoms. Preferred specific examples of Z further include a hydrogen atom, a chlorine atom, and a bromine atom.

[0025] X and Y are each a hydrogen atom, a halogen atom, a hydrocarbon group with 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, an alkoxy group with 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, an amino group, a hydrocarbon group containing a phosphorus atom with 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms such as a diphenylphosphino group, or a hydrocarbon group containing a silicon atom with 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms such as a trimethylsilyl group or a bis(trimethylsilyl)methyl group. X and Y may be the same or different. Among these, a halogen atom, a hydrocarbon group with 1 to 10 carbon atoms, and an amino group with 1 to 12 carbon atoms are particularly preferred.

[0026] Specific examples of the compounds represented by the general formulas (1) to (4) include, but are not limited to, the specific examples described in paragraphs 0098 to 0106 of International Publication No. 2022 / 059764.

[0027] In addition, as the metallocene complex, a metallocene complex represented by the following general formula [I] is also preferably used.

[0028] [Chemical formula] (In formula [I], M is Ti, Zr or Hf; Q is a carbon atom, a silicon atom or a germanium atom; X 1 and X 2 are each independently a halogen atom, an alkyl group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms, an amino group substituted with an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen-containing alkyl group having 1 to 6 carbon atoms or a halogen-containing aryl group having 6 to 18 carbon atoms. R 1 and R 11 may be the same as or different from each other, and are a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a furyl group, a thienyl group, a furyl group having a substituent or a thienyl group having a substituent, provided that one or both of R 1 and R 11 are necessarily one of a furyl group, a thienyl group, a furyl group having a substituent or a thienyl group having a substituent. R 7 and R 17 may be the same as or different from each other, and are a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen-containing alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms having a trialkylsilyl group, a silyl group having a hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms or a halogen-containing aryl group having 6 to 18 carbon atoms, provided that when either R 7 or R 17 is a hydrogen atom, one is a substituent other than a hydrogen atom. R 8 and R 18may be the same as or different from each other, and is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen-containing alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms with a trialkylsilyl group, a silyl group having a hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms or a halogen-containing aryl group having 6 to 18 carbon atoms. Also, R 7 、R 8 、R 17 and R 18 may form a 5- to 7-membered ring with both adjacent substituents, and the 5- to 7-membered ring may contain an unsaturated bond. R 2 、R 3 、R 4 、R 5 、R 6 、R 9 、R 12 、R 13 、R 14 、R 15 、R 16 and R 19 may be the same as or different from each other, and is a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen-containing alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms with a trialkylsilyl group, an aryl group having 6 to 18 carbon atoms, a halogen-containing aryl group having 6 to 18 carbon atoms, a furyl group, a thienyl group, a furyl group having a substituent or a thienyl group having a substituent. Also, R 2 、R 3 、R 4 、R 5 、R 6 、R 12 、R 13 、R 14 、R 15 and R 16 may form a 5- to 7-membered ring with both adjacent substituents, and the 5- to 7-membered ring may contain an unsaturated bond. A is a divalent hydrocarbon group having 3 to 12 carbon atoms that forms a ring with Q to which it is bonded, and may contain an unsaturated bond. R 10is a substituent of A, which is an alkyl group having 1 to 6 carbon atoms, a halogen-containing alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 6 carbon atoms with a trialkylsilyl group, a silyl group having a hydrocarbon group having 1 to 6 carbon atoms, an aryl group having 6 to 18 carbon atoms or a halogen-containing aryl group having 6 to 18 carbon atoms. m represents an integer from 0 to 24. When m is 2 or more, R 10 may be linked to each other to form a new ring structure.)

[0029] The description of each symbol of the metallocene complex represented by the general formula [I] is incorporated into the present specification as described in paragraphs 0031 to 0055 of JP-A-2015-193605. Specific examples of the metallocene complex represented by the general formula [I] include those described in paragraphs 0056 to 0063 of JP-A-2015-193605.

[0030] Regarding the (a) metallocene complex in the metallocene catalyst, one kind can be used, or two or more kinds can be used in combination.

[0031] Examples of the compound or ion-exchangeable layered silicate that reacts with the (b) metallocene complex in the metallocene catalyst to form an ion pair include aluminum oxy compounds, boron compounds, ion-exchangeable layered silicates, etc., and preferably an ion-exchangeable layered silicate. These components (b) may be used alone or in combination of two or more. The compound or ion-exchangeable layered silicate that reacts with the metallocene complex to form an ion pair may be the same as described in paragraphs 0071 to 0086 of JP-A-2015-193605.

[0032] The organoaluminum compound used as a cocatalyst is not particularly limited, and has the general formula (AlR n X 3-n ) mIt may be an organoaluminum compound represented by the formula: In the formula, R represents an alkyl group having 1 to 20 carbon atoms, X represents a halogen atom, a hydrogen atom, an alkoxy group or an amino group, n represents an integer of 1 to 3, and m represents an integer of 1 to 2. The organoaluminum compound can be used alone or in combination of two or more.

[0033] Specific examples of the organoaluminum compound include trimethylaluminum, triethylaluminum, trinormalpropylaluminum, trinormalbutylaluminum, triisobutylaluminum, trinormalhexylaluminum, trinormaloctylaluminum, trinormaldecylaluminum, diethylaluminum chloride, diethylaluminum sesquichloride, diethylaluminum hydride, diethylaluminum ethoxide, diethylaluminum dimethylamide, diisobutylaluminum hydride, diisobutylaluminum chloride, and the like. Among these, preferably, they are trialkylaluminum and alkylaluminum hydride where m = 1 and n = 3. More preferably, it is trialkylaluminum where R has 1 to 8 carbon atoms.

[0034] The preparation of the olefin polymerization catalyst used in the present invention may be appropriately selected from conventionally known preparation methods and is not particularly limited.

[0035] The olefin polymerization catalyst used in the present invention may be subjected to a prepolymerization treatment which consists of bringing the olefin into contact and polymerizing it in a small amount. The olefin used in the prepolymerization treatment is not particularly limited, and ethylene, propylene, 1-butene, 1-hexene, 1-octene, 4-methyl-1-pentene, 3-methyl-1-butene, vinyl cycloalkane, or styrene, etc. can be used, and it is particularly preferable to use ethylene or propylene. The method for supplying olefin can be any method. For example, there are methods such as supplying olefin to the polymerization tank at a constant speed or maintaining it in a constant pressure state and combinations thereof, and methods such as making stepwise changes.

[0036] The prepolymerization temperature and prepolymerization time are not particularly limited, but are preferably in the ranges of -20°C to 100°C and 5 minutes to 24 hours, respectively. Also, the prepolymerization amount is, for example, the mass ratio of the prepolymer to the solid catalyst component (X) is preferably 0.01 to 100, more preferably 0.1 to 50. Also, a cocatalyst can be added during prepolymerization. The catalyst may be dried after prepolymerization. The drying method is not particularly limited, but examples include drying under reduced pressure, drying by heating, and drying by passing a drying gas. These methods may be used alone or in combination of two or more. In the drying process, the catalyst may be stirred, vibrated, fluidized, or allowed to stand.

[0037] The average particle size of the olefin polymerization catalyst used in the present invention is not particularly limited. The average particle size of the olefin polymerization catalyst used in the present invention is usually 0.1 μm or more, but may be 40 μm or more, may be 70 μm or more, and is usually 300 μm or less. According to the present invention, since clogging of the catalyst supply line can be suppressed, in the present invention, an olefin polymerization catalyst having a relatively large particle size can be used. The average particle size of the olefin polymerization catalyst used in the present invention is the median diameter (D50) in the volume-based particle size distribution, and is a value obtained by the laser diffraction method using a laser diffraction particle size measuring device (for example, Mastersizer manufactured by Malvern Panalytical).

[0038] According to the present invention, since clogging of the catalyst supply line can be suppressed, in the present invention, an olefin polymerization catalyst having a high sedimentation rate can also be suitably used. Examples of the olefin polymerization catalyst having a high sedimentation rate include an olefin polymerization catalyst having a large weight of the solid catalyst component, and an olefin polymerization catalyst containing a metallocene complex containing a zirconium atom or a hafnium atom.

[0039] 2. Poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) In the method for producing an olefin polymer of the present invention, the poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer to be supplied is represented by the following general formula (I). Formula (I): HO-(C3H6O) a -(C2H4O) b -(C3H6O) c -H [In the general formula (I), a and c are each independently an integer of 1 to 60, b is an integer of 1 to 29, and a + c = 2 to 120, and a + b + c ≧ 3 is satisfied.]

[0040] In the production of an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing the solid catalyst component of the present invention, by bringing the specific PPG-PEG-PPG block copolymer (G) into contact with the olefin polymerization catalyst containing the solid catalyst component (X) and then supplying it to the polymerization tank, clogging of the catalyst supply line can be suppressed, and generation of coarse particles due to adhesion of polymer particles to each other can be suppressed. The reason for the excellent effect is not clear, but it can be considered as follows. Before supplying to the overlapping groove, by bringing the specific PPG-PEG-PPG block copolymer (G) into contact with the olefin polymerization catalyst containing the solid catalyst component (X), the PPG-PEG-PPG block copolymer (G) protects the surface of the catalyst particles, so that the dispersibility of the catalyst becomes good, aggregation of the catalysts hardly occurs, blockage of the catalyst supply line can be suppressed, and it is considered that the catalyst can be stably supplied to the polymerization tank. Further, it is considered that the catalyst particles protected by the PPG-PEG-PPG block copolymer (G) on the surface are also well dispersed in the olefin in the polymerization tank, and it becomes easier to avoid contact between the catalyst particles. When the catalysts are present close to each other, the polymer is likely to melt due to the heat of the exothermic reaction in which the polymer grows and form aggregates. However, in the present invention, it is considered that aggregation of the polymer powder during polymerization is suppressed because the dispersibility of the catalyst in the polymerization tank becomes good. The PPG-PEG-PPG block copolymer is more likely to dissolve in a hydrophobic hydrocarbon solvent used when slurrying the catalyst, compared to, for example, a PEG-PPG-PEG block copolymer, and it is considered that it is easy to improve the dispersibility of the catalyst by protecting the surface of the catalyst particles while loosening the aggregation of the catalysts in the catalyst slurry. Also, although the protection mechanism of the catalyst particle surface is not clear, it is considered that the hydrophobic PPG chains are attracted to the surrounding hydrocarbon solvent or olefin, and the hydrophilic PEG chains act on the catalyst particles, so that the catalyst surface is covered with a polymer, making it easier to avoid aggregation and contact between the catalyst particles. Since the PPG-PEG-PPG block copolymer has hydrophobic PPG arranged on the outside, it has a high affinity for propylene, and in propylene polymerization, its dispersibility in the polymerization tank is particularly good, and it is considered that aggregation of the polymer powder during polymerization is easily suppressed.

[0041] In the general formula (I), a and c are each independently an integer of 1 to 60, and satisfy a + c = 2 to 120. The PPG part, which is a hydrophobic group, is considered to provide characteristics such as dispersibility in hydrocarbon solvents and olefins. From the viewpoint of handleability during production, such as viscosity adjustment, a + c is preferably 100 or less, more preferably 80 or less. Also, from the viewpoint of the hydrophobic function, a + c is preferably 10 or more, more preferably 20 or more.

[0042] In the general formula (I), b is an integer from 1 to 29. The PEG part, which is a hydrophilic group, is considered to provide characteristics such as the effect of reducing the surface potential resistance as a surfactant. From the viewpoint of the hydrophilic function, b is preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more. Also, so that the solubility in hydrocarbon solvents and olefins does not decrease too much, b is preferably 25 or less, more preferably 20 or less, and even more preferably 15 or less.

[0043] In the general formula (I), from the viewpoint of suppressing the decrease in catalytic activity, preferably a + c > b.

[0044] a + b + c is 3 or more, but may be 4 or more, and may be 5 or more. On the other hand, from the viewpoint of handleability during production, a + b + c is 120 or less, but may be 110 or less, and may be 100 or less. a + b + c is preferably 10 to 80, more preferably 20 to 70, from the viewpoints of suppressing the decrease in catalytic activity, improving the effect of suppressing the blockage of the catalyst supply line, and improving the effect of suppressing the aggregation and adhesion of the polymer powder.

[0045] The number average molecular weight of the PPG-PEG-PPG block copolymer (G) used in the present invention is 500 or more, more preferably 700 or more, still more preferably 900 or more from the viewpoint of suppressing the decrease in catalytic activity, and may be 1200 or more, or may be 1500 or more. On the other hand, from the viewpoint of the dispersibility of the PPG-PEG-PPG block copolymer (G) in hydrocarbon solvents and olefins, the upper limit is 8000 or less, preferably 6000 or less, more preferably 5000 or less. Any combination of the above upper and lower limits can be adopted.

[0046] The PPG-PEG-PPG block copolymer (G) used in the present invention preferably dissolves in hexane at 26 ° C. at 5 mg / mL (hexane) or more, more preferably 50 mg / mL (hexane) or more, and still more preferably at a concentration of 350 mg / mL (hexane) from the viewpoint of improving the effect of suppressing the blockage of the catalyst supply line.

[0047] As the PPG-PEG-PPG block copolymer (G) used in the present invention, commercially available products can be appropriately selected and used. Commercially available products include, for example, poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol) (trade name, Sigma-Aldrich), Pluronic® (registered trademark, BASF), and Adeka Pluronic® (registered trademark, ADEKA). They are commercially available under names such as 31R1, 25R1, 10R5, 10R8, 17R2, 17R4, 25R2, 25R4, etc.

[0048] 3. Method for producing olefin polymer The method for producing an olefin polymer of the present invention is a method for producing an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing the solid catalyst component (X), characterized in that the specific PPG-PEG-PPG block copolymer (G) is contacted with the solid catalyst component (X) and then supplied to the polymerization tank. The method for producing an olefin polymer homopolymerizes or copolymerizes an olefin in the presence of the olefin polymerization catalyst. That is, in this production method, one type of olefin is polymerized, or two or more types of olefins are copolymerized. In the present specification, the polymer means at least one of a homopolymer and a copolymer.

[0049] In the case of copolymerization, the quantitative ratio of each monomer in the reaction system does not necessarily have to be constant over time, and it is also possible to supply each monomer at a constant mixing ratio. Further, it is also possible to change the mixing ratio of the monomers to be supplied over time. Further, it is also possible to add one of the monomers in portions in consideration of the copolymerization reaction ratio.

[0050] As the olefin capable of polymerization, an olefin having 2 to 20 carbon atoms is preferable, and specifically, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, styrene, divinylbenzene, 7-methyl-1,7-octadiene, cyclopentene, norbornene, ethylidene norbornene, etc. are mentioned. Preferably, they are ethylene, propylene, and α-olefins having 4 to 8 carbon atoms, and more preferably ethylene or propylene.

[0051] Among them, propylene homopolymerization or copolymerization of propylene with at least one comonomer selected from ethylene and α-olefins having 4 or more carbon atoms is preferable, and copolymerization of propylene and ethylene is particularly preferable.

[0052] The polymerization mode is not particularly limited as long as the olefin polymerization catalyst containing the solid catalyst component (X) comes into efficient contact with the olefin, and it may be a gas-phase polymerization method. The gas-phase polymerization apparatus used in the method for producing an olefin polymer of the present invention may have at least a polymerization tank equipped with stirring blades, and may further have a catalyst pretreatment section.

[0053] As the polymerization tank, a horizontal polymerization tank or a vertical polymerization tank is preferable. As the horizontal polymerization tank having a stirring blade, those described in JP-A-63-223001 etc. can be used, and as the vertical polymerization tank having a stirring blade, those described in JP-A-53-123487, JP-A-54-23258 etc. can be used. In addition to these polymerization tanks being single-stage or single polymerization tanks, they may also have a plurality of polymerization tanks in two or more stages.

[0054] Further, the gas-phase polymerization apparatus used in the method for producing an olefin polymer of the present invention may further include a monomer supply line, a monomer circulation line, a catalyst supply line, a polymer discharge line, a gas-solid separation device, a granulator, a compressor, a condenser, etc. The monomer supply line is a pipe for continuously supplying an olefin monomer to be used in polymerization to the polymerization tank. The polymer discharge line is a pipe for continuously withdrawing the polymerized polymer in a steady or intermittent manner. The gas-solid separation device is a device for separating the polymer and the monomer. The compressor and the condenser are devices for liquefying the monomer gas in the polymerization tank. The monomer circulation line is a pipe for circulating the liquefied monomer to the polymerization tank. Also, a method is adopted in which this liquefied monomer vaporizes in the polymerization tank and the heat of polymerization is removed by its latent heat of evaporation. Further, the catalyst supply line is a pipe for continuously or intermittently supplying an olefin polymerization catalyst to the polymerization tank, and when including a catalyst supply nozzle, it includes both the pipe and the nozzle. The olefin polymerization catalyst may be supplied into the polymerization tank together with a monomer or an organoaluminum compound as a cocatalyst. Therefore, the catalyst supply line may be connected to the polymerization tank integrally with the monomer supply line and / or the monomer circulation line and / or the organoaluminum compound supply line for the cocatalyst.

[0055] [Contact between the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X)] In the method for producing an olefin polymer of the present invention, after bringing the specific PPG-PEG-PPG block copolymer (G) into contact with the solid catalyst component (X), a mixture of the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) is supplied to a polymerization tank. The contact between the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) may be achieved by contacting and mixing an olefin polymerization catalyst containing the solid catalyst component (X) with the specific PPG-PEG-PPG block copolymer (G).

[0056] The method of contacting the specific PPG-PEG-PPG block copolymer (G) with the solid catalyst component (X) may be either a method of adding the solid catalyst component (X) to the specific PPG-PEG-PPG block copolymer (G) or a method of adding the specific PPG-PEG-PPG block copolymer (G) to the solid catalyst component (X).

[0057] The contact between the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) can be carried out in a device or part having a function of contacting and mixing as a catalyst pretreatment section. As the catalyst pretreatment section, for example, a storage tank having a stirring device, a pipe capable of turbulent mixing or static stirring mixing, etc. can be appropriately selected and used. Further, the specific PPG-PEG-PPG block copolymer (G) may be directly supplied to a catalyst storage tank for storing the catalyst to be supplied to the polymerization tank, and the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) may be brought into contact in the catalyst storage tank. Further, a supply section of the specific PPG-PEG-PPG block copolymer (G) may be provided in the middle of the catalyst supply line connected from the catalyst storage tank to the polymerization tank, and the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) may be brought into contact and mixed in the pipe. The olefin polymerization catalyst containing the solid catalyst component (X) contacted with the specific PPG-PEG-PPG block copolymer (G) in the catalyst pretreatment section may be continuously or intermittently supplied to the polymerization tank through the catalyst supply line. Among them, the contact between the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) is preferably carried out in a catalyst storage tank or a catalyst supply line.

[0058] Further, the specific PPG-PEG-PPG block copolymer (G) and / or the solid catalyst component (X) may be contacted in a state diluted with a solvent. When a solvent is used during the contact, it is preferably appropriately selected from inactive hydrocarbon solvents. As the hydrocarbon solvent, a saturated aliphatic or aromatic hydrocarbon such as hexane, heptane, pentane, cyclohexane, benzene, or toluene alone or as a mixture can be used. Also, the temperature may be adjusted by heating, cooling, etc. to adjust the solubility and viscosity in the solvent. Among them, after contacting the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) in a hydrocarbon solvent, supplying the obtained catalyst slurry to a polymerization tank is preferable from the viewpoint of improving the effect of suppressing clogging of the catalyst supply line.

[0059] The contact amount of the specific PPG-PEG-PPG block copolymer (G) may be appropriately adjusted, but is preferably 0.5% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass, based on the solid catalyst component (X). When the contact amount is not less than the lower limit value, the effect of suppressing clogging of the catalyst supply line is likely to be improved, and when it is not more than the upper limit value, the influence on the catalyst performance is less likely to occur.

[0060] Also, when contacting in the solvent, the concentration of the PPG-PEG-PPG block copolymer (G) in the solvent may be appropriately selected according to the viscosity of the solution depending on the temperature and the addition amount. The concentration of the PPG-PEG-PPG block copolymer (G) may be 0.01 mg to 1.5 mg, or may be 0.02 mg to 1.2 mg, per 1 mL of the solvent.

[0061] The conditions for the contact between the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) are not particularly limited. Usually, it can be carried out by contacting at a temperature of -10°C to 60°C and a pressure of normal pressure to 2 MPa for 1 second or more, preferably 1 minute or more. When the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) are contacted, in order to increase the contact efficiency and maintain uniformity, it is desirable to stir the mixture of the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X).

[0062] After the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) are contact-mixed, by supplying the mixture to the polymerization tank, blockage of the catalyst supply line can be suppressed. Further, due to the good dispersibility of the catalyst in the polymerization tank, the catalytic action in the polymerization tank can be made uniform, and the generation and agglomeration of coarse particles due to the adhesion of polymer particles can be suppressed and drastically reduced. As a result, long-term stable supply of the catalyst and destabilization of the operating state due to coarse particles can be suppressed, and long-term continuous operation can be enabled.

[0063] Hereinafter, regarding the method for producing an olefin polymer of the present invention, a method for producing a random copolymer, which is an example of the method for producing an olefin polymer of the present invention, will be described as an example. In the method for producing an olefin polymer of the present invention, when producing a random copolymer, propylene and other α-olefins such as ethylene are supplied from a monomer supply line to a polymerization tank, and while being stirred by a polymerization tank stirring blade, a random copolymer of propylene and other α-olefins such as ethylene is continuously polymerized. After the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) are contacted in the catalyst storage tank or the catalyst supply line at the aforementioned ratio and conditions, they are supplied to the polymerization tank through the catalyst supply line. The supply of the mixture of the specific PPG-PEG-PPG block copolymer (G) and the solid catalyst component (X) to the polymerization tank is carried out continuously or intermittently.

[0064] The production of the random copolymer can also be carried out by multi-stage polymerization if necessary. In the case of multi-stage polymerization, as an olefin polymerization catalyst containing the solid catalyst component (X), for the purposes of improving catalytic activity, bulk density, and the fluidity of polymer particles, etc., a prepolymerized catalyst that has been previously subjected to a treatment of contacting with a small amount of monomers such as propylene can also be used.

[0065] In each polymerization tank, for example, the molecular weight is adjusted using hydrogen or the like at a polymerization temperature of 50°C to 70°C and a polymerization pressure of about 1.6 MPa to 2.4 MPa. The composition of propylene and α-olefins such as ethylene in the polymer is adjusted by the supply amounts of the respective monomers. The polymer particles polymerized in the polymerization tank are transferred to a hopper or the like through a polymer discharge line.

[0066] [Olefin Polymer] The olefin polymer obtained by the method for producing an olefin polymer of the present invention is preferably a propylene homopolymer, or a copolymer of a propylene homopolymer, or propylene and at least one comonomer selected from ethylene and α-olefins having 4 or more carbon atoms, and particularly preferably a random copolymer of propylene and at least one comonomer selected from ethylene and α-olefins having 4 or more carbon atoms. Among others, the olefin polymers obtained by the method for producing an olefin polymer of the present invention preferably include a propylene homopolymer, a propylene-ethylene block copolymer, a propylene-ethylene random copolymer, a propylene / ethylene-olefin copolymer, etc.

Examples

[0067] Next, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples as long as the gist thereof is not deviated from. The measurement methods in the present examples are as follows.

[0068] [Evaluation Method] 1. Powder Agglomeration Ratio The polymer powder obtained by polymerization was collected and its weight was measured. The entire amount of the collected sample powder was placed on a sieve with an opening of 3350 μm, shaken well, the weight of the polymer remaining on the sieve was measured, and it was calculated by the following formula. Powder agglomerate ratio (wt%) = amount of polymer powder remaining on sieve ÷ amount of polymer powder charged into sieve × 100

[0069] 2. Average particle size of olefin polymerization catalyst The average particle size of the olefin polymerization catalyst was measured by the laser diffraction method using a laser diffraction particle size analyzer (Mastersizer manufactured by Malvern Panalytical). Kerosene (refractive index 1.44) was used as the dispersion medium. The powder sample was charged so that the scattering intensity was 5 - 20%, and the particle size was measured. The median diameter (D50) was determined from the obtained volume-based particle size distribution.

[0070] [Synthesis Example 1: Production of olefin polymerization catalyst] A catalyst was prepared in the same manner as the catalyst preparation (Catalyst G) using dichlorosilacyclobutylene bis[2-(5-methyl-2-furyl)-4-(4-t-butylphenyl)-5,6-dimethyl-1-indenyl]zirconium (Metallocene complex G) of Example 7 of JP-A-2015-193605, and an olefin polymerization catalyst with a prepolymerization magnification (value obtained by dividing the amount of prepolymer by the amount of solid catalyst) of 2.23 with respect to propylene was obtained. The average particle size of the olefin polymerization catalyst was 77 μm.

[0071] [Example 1] (1) Pretreatment of prepolymerization catalyst (contact between PPG-PEG-PPG block copolymer (G) and solid catalyst component (X)) Into a catalyst storage tank equipped with a stirrer that had been sufficiently replaced with nitrogen gas, 620 g of the olefin polymerization catalyst with a prepolymerization magnification of 2.23 was charged, and 5.3 g of a PPG-PEG-PPG block copolymer (G-1) (trade name: poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), obtained from Sigma-Aldrich, number average molecular weight of about 3300, a + c = 48, a ≥ 1, c ≥ 1, b = 12) was added. The total volume was adjusted to 32 liters with purified hexane, and after stirring, the resulting catalyst slurry was directly used for the following bulk polymerization.

[0072] (2) Bulk polymerization Bulk polymerization was carried out using a polymerization apparatus having a polymerization tank equipped with a stirring blade and a catalyst storage tank. Hereinafter, the bulk polymerization will be described in detail. Liquefied propylene, which is also used for heat removal of the polymerization reaction, was supplied to a polymerization tank with an internal volume of 157 L at a rate of 30 - 50 kg / hr, hydrogen was supplied so that the gas concentration was a molar ratio of hydrogen to propylene of 0.00032 - 0.0054, triisobutylaluminum was supplied at 88 g / hr, and the catalyst slurry of the pretreated prepolymerization catalyst was intermittently supplied at a flow rate of 0.62 - 1.1 g / hr (by the weight of the solid catalyst component (X) excluding the prepolymerized polymer). Polymerization was carried out by gradient polymerization at a temperature of 54.5 - 55.5 °C. The extraction rate of the propylene-based polymer powder was 6.7 - 9.8 kg / h.

[0073] The above polymerization operation was continued for 313 hours, and then the operation was stopped plannedly. As a result of visually observing the catalyst supply line including the catalyst supply nozzle after opening the polymerization apparatus, no blockage was observed. When evaluating the lump rate of the produced propylene polymer powder, the lump rate of the powder was 0.00 wt%. The results are shown in Table 1.

[0074] [Example 2] Propylene was polymerized in the same manner as in Example 1, except that the addition amount of the PPG-PEG-PPG block copolymer (G-1) used in the pretreatment of the prepolymerization catalyst in Example 1(1) was changed as shown in Table 1. The above polymerization operation was continued for 313 hours and then the operation was stopped plannedly. After opening the polymerization apparatus and visually observing the catalyst supply line including the catalyst supply nozzle, no clogging was found. When evaluating the lump ratio of the produced propylene polymer powder, the lump ratio of the powder was 0.00 wt%. The results are shown in Table 1.

[0075] [Example 3] Random copolymerization was carried out by supplying propylene, ethylene, and hydrogen in the same addition amount as the PPG-PEG-PPG block copolymer (G-1) used in Example 2 to obtain a polymer powder. Specifically, 30 to 60 kg / hr of liquefied propylene, which is also used for heat removal of the polymerization reaction, was supplied to a polymerization tank with an internal volume of 157 L. Hydrogen was supplied so that the gas concentration was 0.00015 to 0.0065 in terms of the molar ratio of hydrogen to propylene, ethylene was supplied so that the molar ratio of ethylene to propylene was 0.0036 to 0.0175, triisobutylaluminum was supplied intermittently at a flow rate of 88 g / hr, and the catalyst slurry of the prepolymerization catalyst was supplied at a flow rate of 0.5 to 0.6 g / hr (by weight of the solid catalyst component (X) excluding the prepolymerized polymer). Polymerization was carried out by gradient polymerization at a temperature of 54.5 to 55.5 °C. The extraction amount of the propylene-based polymer powder was 8.0 to 10.0 kg / h. The above polymerization operation was continued for 313 hours and then the operation was stopped plannedly. After opening the polymerization apparatus and visually observing the catalyst supply line including the catalyst supply nozzle, no clogging was found. When evaluating the lump ratio of the produced propylene-based polymer powder, the lump ratio of the powder was 0.00 wt%. The results are shown in Table 1.

[0076] [Comparative Example 1] A catalyst slurry was prepared in the same manner as in Example 1(1) except that the PPG-PEG-PPG block copolymer (G) was not added to the catalyst storage tank, and propylene polymerization was carried out in the same manner as in Example 1. After 42 hours, the temperature in the reactor began to drop rapidly, so the operation was stopped urgently. After opening the polymerization apparatus and visually observing the catalyst supply line, blockages were found in the catalyst supply line and the catalyst supply nozzle. When evaluating the lump ratio of the produced propylene polymer powder, the lump ratio of the powder was 0.22 wt%. The results are shown in Table 1.

[0077] [Table 1]

[0078] [Example 4] (1) Pretreatment of the prepolymerization catalyst 780 mg of the olefin polymerization catalyst with a prepolymerization ratio of 2.23 was charged into a flask that had been sufficiently purged with nitrogen gas and into which a stirrer had been inserted. 1.35 mg of PPG-PEG-PPG block copolymer (G-1) was added, and the total volume was adjusted to 52 mL with purified heptane. After stirring, the catalyst slurry was directly used for the following bulk polymerization.

[0079] (2) Bulk polymerization Bulk polymerization was carried out using a polymerization apparatus equipped with a stirring blade. Hereinafter, the bulk polymerization will be described in detail. The inside of a 3 L stirred autoclave was sufficiently purged with propylene. Then, 2.8 mL (2.02 mmol) of a heptane solution of triisobutylaluminum (TiBA) was added. Next, 350 mL of hydrogen and 750 mL of liquid propylene were introduced, and the temperature was raised to 80 °C. 3.3 mL of the catalyst slurry (50 mg of solid catalyst component (X)) was collected and injected into the autoclave under pressure. After polymerizing at 80 °C for 1 hour, 10 mL of ethanol was added to stop the polymerization reaction.

[0080] After purging the remaining propylene, about 300 g of propylene polymer powder was recovered and dried at 90 °C for 30 minutes. When evaluating the lump ratio of the produced propylene polymer powder, the lump ratio of the powder was 0.00 wt%. The results are shown in Table 2.

[0081] [Examples 5 to 8] Propylene was polymerized in the same manner as in Example 4, except that the addition amount of the PPG-PEG-PPG block copolymer (G-1) used in the pretreatment of the prepolymerization catalyst of Example 4(1) was changed as shown in Table 1, to obtain a propylene polymer powder. When the lump ratio of the produced propylene polymer powder was evaluated, the lump ratio of the powder in each example was 0.00 wt%. The results are shown in Table 2.

[0082] [Example 9] Propylene was polymerized in the same manner as in Example 4, except that the PPG-PEG-PPG block copolymer (G-1) used in the pretreatment of the prepolymerization catalyst of Example 4(1) was changed to a PPG-PEG-PPG block copolymer (G-2) (trade name: poly(propylene glycol)-block-poly(ethylene glycol)-block-poly(propylene glycol), obtained from Sigma-Aldrich, number average molecular weight about 2000, a + c = 17, b = 23), and the addition amount was changed as shown in Table 2, to obtain a propylene polymer powder. When the lump ratio of the produced propylene polymer powder was evaluated, the lump ratio of the powder was 0.00 wt%. The results are shown in Table 2.

[0083] [Comparative Example 2] A catalyst slurry was prepared in the same manner as in Example 4(1), except that the PPG-PEG-PPG block copolymer (G) was not added to the flask, and propylene polymerization was carried out in the same manner as in Example 4. When the lump ratio of the produced propylene polymer powder was evaluated, the lump ratio of the powder was 22.00 wt%. The results are shown in Table 2.

[0084]

Table 2

[0085] [Summary of Results of Examples] By comparing Examples 1 to 3 with Comparative Example 1, according to the present invention, by contacting the specific PPG-PEG-PPG block copolymer (G) with the solid catalyst component (X) and then supplying it to the polymerization tank, it was shown that clogging of the catalyst supply line can be suppressed, and generation of coarse particles due to adhesion of polymer particles can be suppressed. Further, even when the specific PPG-PEG-PPG block copolymer (G) is contacted with the solid catalyst component (X) and then supplied to the polymerization tank, it has no effect on the physical properties of the polymer and also has no effect on polymerization performance such as responsiveness to comonomers such as hydrogen and ethylene and polymerization activity. By comparing Examples 4 to 9 with Comparative Example 2, according to the present invention, by contacting the specific PPG-PEG-PPG block copolymer (G) with the solid catalyst component (X) and then supplying it to the polymerization tank, it was shown that generation of coarse particles due to adhesion of polymer particles can be suppressed.

[0086] [Reference Example] For stable supply of the olefin polymerization catalyst containing the solid catalyst component (X), it is preferable that the clogging inhibitor is easily dissolved in the organic solvent to be introduced. Further, if the sedimentation rate of the olefin polymerization catalyst containing the solid catalyst component (X) is high, the catalyst particles tend to accumulate at the lower part of the storage tank early, and when they flow out into the catalyst supply line all at once, the catalyst supply line tends to be clogged. Therefore, it is preferable to reduce the sedimentation rate of the olefin polymerization catalyst containing the solid catalyst component (X) and to equalize the catalyst concentration inside the catalyst storage tank. In the reference example, as an evaluation measurement of the effect that occurs when the prepolymerization catalyst and the clogging inhibitor are premixed in the catalyst storage tank under the following conditions, viscosity measurement of the PPG-PEG-PPG block copolymer (G) alone, confirmation of the solubility of the clogging inhibitor in the organic solvent (26 °C and 4 °C), and measurement of the sedimentation rate of the catalyst were performed. [Viscosity Measurement] The viscosity of the PPG-PEG-PPG block copolymer (G) was measured at 25 °C using a rotational rheometer (ARES-G2, manufactured by TA Instruments). [Confirmation of Solubility in Organic Solvent] 100 mL of hexane and 5 g of a block copolymer (PPG-PEG-PPG) as a clogging inhibitor were added to a flask, and the solubility of the clogging inhibitor at 26°C was confirmed. Also, 100 mL of hexane and 5 g of a block copolymer (PPG-PEG-PPG) as a clogging inhibitor were added to a flask, and the solubility of the clogging inhibitor at 4°C was confirmed.

[0087] [Reference Example 1] 10 g of the olefin polymerization catalyst with a prepolymerization magnification of 1.91 was charged into a graduated cylinder, 3.4 mg of the PPG-PEG-PPG block copolymer (G-1) as a clogging inhibitor was added, and the volume was adjusted to 100 mL with hexane. The sedimentation rate was measured when the catalyst was suspended. The sedimentation rate was 1.55 mm / s. Also, the PPG-PEG-PPG block copolymer (G-1) was easily soluble in hexane. The results are shown in Table 3.

[0088] [Reference Examples 2 to 3] Evaluation was carried out in the same manner as in Reference Example 1, except that the addition amount of the PPG-PEG-PPG block copolymer (G-1) in Reference Example 1 was changed as shown in Table 3. The results are shown in Table 3.

[0089] [Reference Example 4] Evaluation was carried out in the same manner as in Reference Example 1, except that the PPG-PEG-PPG block copolymer (G-1) in Reference Example 1 was changed to the PPG-PEG-PPG block copolymer (G-2), and the addition amount was changed as shown in Table 3. The results are shown in Table 3.

[0090] [Comparative Reference Example 1] The same procedure as in Reference Example 1 was carried out, except that the PPG-PEG-PPG block copolymer was not added in Reference Example 1. The sedimentation rate was 2.27 mm / s. The results are shown in Table 3.

[0091]

Table 3

[0092] By comparing Comparative Reference Example 1 with Reference Examples 1 to 4, it was shown that even in the case of an olefin polymerization catalyst containing a solid catalyst component (X) with a high sedimentation rate as measured in Comparative Reference Example 1, by bringing the PPG-PEG-PPG block copolymer (G-1) or (G-2) having the viscosity and solubility in hexane as described above into contact and mixing with the olefin polymerization catalyst containing the solid catalyst component (X), an effect of reducing the sedimentation rate can be obtained. The effect of reducing the sedimentation rate of the olefin polymerization catalyst can also be obtained similarly in the catalyst storage tank or the catalyst supply line, suggesting that it contributes to suppressing the aggregation of the catalyst and making the catalyst concentration uniform inside the catalyst storage tank.

Industrial Applicability

[0093] The method for producing an olefin polymer according to the present invention can suppress the blockage of the catalyst supply line and suppress the generation of coarse particles due to the adhesion of polymer particles without affecting the polymerization performance such as hydrogen responsiveness and polymerization activity and the physical properties of the polymer in the production of an olefin polymer by polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component. The method for producing an olefin polymer according to the present invention can suppress the long-term stable supply of the catalyst, suppress the destabilization of the operating state due to coarse particles, enable long-term continuous operation, and suppress the deterioration of the quality of the final molded product. The method for producing an olefin polymer according to the present invention can be particularly preferably employed in the production of a random copolymer of propylene and other α-olefins and is extremely valuable industrially.

Claims

1. A method for producing an olefin polymer, comprising polymerizing an olefin in the presence of an olefin polymerization catalyst containing a solid catalyst component (X), A method for producing an olefin polymer, comprising contacting a poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) represented by the following general formula (I) with a solid catalyst component (X) and then supplying the resulting mixture to a polymerization tank. HO-(C ３ H ６ O) ａ -(C ２ H ４ O) ｂ -(C ３ H ６ O) ｃ -H・・・(I) [In the general formula (I), a and c are each independently an integer of 1 to 60, b is an integer of 1 to 29, and a+c=2 to 120, and a+b+c≧3 are satisfied.]

2. The method for producing an olefin polymer according to claim 1, characterized in that the poly(propylene glycol)-poly(ethylene glycol)-poly(propylene glycol) block copolymer (G) represented by the general formula (I) is contacted with a solid catalyst component (X) in a hydrocarbon solvent, and then the obtained catalyst slurry is supplied to a polymerization tank.

3. 3. The process for producing an olefin polymer according to claim 1, wherein the contact is carried out in a catalyst storage tank or a catalyst supply line.

4. 3. The method for producing an olefin polymer according to claim 1, wherein the contact amount of the block copolymer (G) is 0.5% by mass to 20% by mass based on the solid catalyst component (X).

5. 3. The method for producing an olefin polymer according to claim 1 or 2, wherein the olefin polymer is a propylene homopolymer or a copolymer of propylene and at least one comonomer selected from ethylene and an α-olefin having 4 or more carbon atoms.

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