JP2019172946A - Method for producing propylene-based polymer - Google Patents

Abstract

To provide a method for producing a propylene-based polymer with a high molecular weight without depending on improvement to a transition metal compound used for a polymerization catalyst.SOLUTION: A method for producing a propylene-based polymer has a polymerization step of polymerizing a propylene in the presence of a propylene polymerization catalyst containing (A) a predetermined transition metal compound and (B) a support having a predetermined solid polyaluminoxane composition, which supports the transition metal compound (A) thereon.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a propylene-based polymer.

  Propylene polymers are used in various applications as thermoplastic resins or as modifiers for thermoplastic resins. As a polymerization catalyst used when producing a propylene polymer, a titanium catalyst, a metallocene catalyst, and the like are known.

  In recent years, in order to produce an α-olefin polymer having improved physical properties, for example, a high-molecular-weight propylene polymer, the transition metal compound (metallocene compound) constituting the metallocene catalyst has been actively improved. . For example, Patent Document 1 describes the homopolymerization of propylene in the presence of a catalyst containing a transition metal compound having a ligand formed by crosslinking a cyclopentadienyl ring and a fluorenyl ring. In Patent Documents 2 to 3, homopolymerization of propylene in the presence of a catalyst containing a transition metal compound having a ligand in which a cyclopentadienyl ring and a fluorenyl ring are bridged via a 5-membered ring is disclosed. Is described.

  On the other hand, Patent Document 4 discloses a solid polyaluminoxane composition having a predetermined characteristic, which is useful as a promoter and a catalyst carrier for a catalyst for producing an olefin polymer.

International Publication No. 2006/025540 International Publication No. 2014/050816 Japanese Patent Application Laid-Open No. 2006-164264 International Publication No. 2014/123212

  As described above, in order to produce a propylene polymer having a high molecular weight, the transition metal compound used for the polymerization catalyst has been conventionally improved. However, the improvement of the transition metal compound cannot be easily achieved. Therefore, if a technique for increasing the molecular weight of the propylene polymer is developed without improving the transition metal compound, its utility value is high.

  Therefore, an object of the present invention is to provide a method for producing a propylene-based polymer having a high molecular weight without depending on the improvement of the transition metal compound used for the polymerization catalyst.

  The present inventors have intensively studied to solve the above problems. As a result, it has been found that the above-described problems can be solved by using a specific transition metal compound as the transition metal compound and a specific solid polyaluminoxane composition as the carrier, and the present invention has been completed.

The gist of the present invention is as follows.
[1]
A method for producing a propylene polymer having a polymerization step of polymerizing propylene in the presence of a propylene polymerization catalyst containing a transition metal compound (A) and a carrier (B),
The transition metal compound (A) is represented by the following general formula [Ia],

[In the formula [Ia], R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, a hydrocarbon group, a heteroatom-containing hydrocarbon group or a silicon-containing group, and any two substituents of R ¹ to R ¹⁶ are bonded to each other. May form a ring,
M is a Group 4 transition metal,
Q is a halogen atom, a hydrocarbon group, an anionic ligand or a neutral ligand capable of coordination with a lone pair, j is an integer of 1 to 4, and j is an integer of 2 or more, Q may be selected in the same or different combinations. ],
The carrier (B) comprises a solid polyaluminoxane composition containing a structural unit represented by the following formula [II] and having an aluminum content of 36% by mass or more,

The transition metal compound (A) is a method for producing a propylene polymer in which the carrier (B) is supported.
[2]
In the general formula [Ia], R ¹ , R ³ , R ⁹ , R ¹² , R ¹³ and R ¹⁶ are hydrogen atoms, R ² is a hydrocarbon group having 1 to 20 carbon atoms, and M is zirconium. A method for producing a propylene polymer according to the above [1].

[3]
The method for producing a propylene-based polymer according to the above [1] or [2], wherein the following general formula [Ia] satisfies the following (1) and (2):
(1) R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
(2) R ¹⁰ , R ¹¹ , R ¹⁴ and R ¹⁵ are each independently a hydrocarbon group or a hydrogen atom, or R ¹⁰ and R ¹¹ are bonded to each other to form a ring, and R ¹⁴ and R ¹⁵ Are bonded to each other to form a ring.

[4]
A method for producing a propylene polymer having a polymerization step of polymerizing propylene in the presence of a propylene polymerization catalyst containing a transition metal compound (A) and a carrier (B),
The transition metal compound (A) is represented by the following general formula [Ib],

[In the formula [Ib], R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ are each independently a hydrogen atom, Two adjacent groups selected from hydrocarbon group, halogen-containing group, oxygen-containing group, nitrogen-containing group, boron-containing group, sulfur-containing group, phosphorus-containing group, silicon-containing group, germanium-containing group and tin-containing group They may combine with each other to form a ring,
M is a Group 4 transition metal atom,
X is each independently an atom or group selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing hydrocarbon group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, and a phosphorus-containing group;
Y is a divalent group, and is a group selected from a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing group, a silicon-containing group, a germanium-containing group, and a tin-containing group. ]
The carrier (B) comprises a solid polyaluminoxane composition containing a structural unit represented by the following formula [II] and having an aluminum content of 36% by mass or more,

The transition metal compound (A) is a method for producing a propylene polymer in which the carrier (B) is supported.
[5]
The method for producing a propylene-based polymer according to any one of [1] to [4], wherein the polymerization method in the polymerization step is bulk polymerization using propylene as a solvent.

[6]
The method for producing a propylene-based polymer according to any one of [1] to [5], wherein the solid polyaluminoxane composition is in the form of particles and the volume-based median diameter (D50) is in the range of 0.1 to 100 μm. .

[7]
The method for producing a propylene-based polymer according to any one of [1] to [6], wherein the solid polyaluminoxane composition satisfies the following requirements (i) and (ii).
Requirement (i): The solubility in n-hexane at 25 ° C. measured by the following method (i) is less than 2.0 mol%.
Requirement (ii): The solubility in toluene at 25 ° C. measured by the following method (ii) is less than 2.0 mol%.

[Method (i)]
2 g of the solid polyaluminoxane composition is added to 50 mL of n-hexane maintained at 25 ° C., followed by stirring for 2 hours, followed by separation into a filtrate and a residue by filtration, and the aluminum in the filtrate. The concentration is measured using ICP emission spectroscopy (ICP-AES), and the solubility is determined as the ratio of aluminum atoms present in the filtrate to the amount of aluminum atoms corresponding to 2 g of the solid polyaluminoxane composition.

[Method (ii)]
Solubility is calculated | required by the method similar to the said method (i) except using toluene instead of n-hexane.

[8]
The propylene-based polymer according to any one of [1] to [7], wherein the solid polyaluminoxane composition is particulate, and the uniformity index represented by the following formula of the composition is 0.45 or less. Production method.

Uniformity index = ΣXi | D50−Di | / D50ΣXi
[Wherein, Xi represents a histogram value of particle i in particle size distribution measurement, D50 represents a volume-based median diameter, and Di represents a volume-based diameter of particle i. ]

  According to the production method of the present invention, a propylene polymer having a high molecular weight can be produced without depending on the improvement of the transition metal compound used for the metallocene catalyst.

Hereinafter, the method for producing a propylene polymer according to the present invention will be described in more detail.
[Propylene polymerization catalyst]
The propylene polymerization catalyst used in the present invention contains a transition metal compound (A) and a carrier (B) described below.

<Transition metal compound (A)>
The transition metal compound (A) used in the present invention is represented by the following general formula [Ia] or the following general formula [Ib].

(Compound represented by the general formula [Ia])

In the formula [Ia], R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ And R ¹⁶ are each independently a hydrogen atom, a hydrocarbon group, a heteroatom-containing hydrocarbon group, or a silicon-containing group, and any two substituents of R ¹ to R ¹⁶ are bonded to each other. A ring may be formed.

  In the formula [Ia], M is a Group 4 transition metal, Q is a halogen atom, a hydrocarbon group, an anionic ligand, or a neutral ligand that can be coordinated by a lone pair, and j is 1 to 1 When Q is an integer of 4 and j is an integer of 2 or more, Q may be selected in the same or different combinations.

<R ¹⁶ from R ^1>
Examples of the hydrocarbon group in R ¹ to R ¹⁶ include one or more of a linear hydrocarbon group, a branched hydrocarbon group, a cyclic saturated hydrocarbon group, a cyclic unsaturated hydrocarbon group, and a saturated hydrocarbon group. And a group formed by substituting a hydrogen atom of a cyclic unsaturated hydrocarbon group. Carbon number of a hydrocarbon group is 1-20 normally, Preferably it is 1-15, More preferably, it is 1-10.

  Examples of the linear hydrocarbon group include methyl group, ethyl group, n-propyl group, n-butyl group, n-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, and n-nonyl. And linear alkyl groups such as n-decanyl group; linear alkenyl groups such as allyl group.

  Examples of the branched hydrocarbon group include isopropyl group, tert-butyl group, tert-amyl group, 3-methylpentyl group, 1,1-diethylpropyl group, 1,1-dimethylbutyl group, 1-methyl-1 Examples thereof include branched alkyl groups such as -propylbutyl group, 1,1-propylbutyl group, 1,1-dimethyl-2-methylpropyl group, and 1-methyl-1-isopropyl-2-methylpropyl group.

  Examples of the cyclic saturated hydrocarbon group include cycloalkyl groups such as cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, and methylcyclohexyl group; and polycyclic groups such as norbornyl group, adamantyl group, and methyladamantyl group. It is done.

  Examples of the cyclic unsaturated hydrocarbon group include an aryl group such as a phenyl group, a tolyl group, a naphthyl group, a biphenyl group, a phenanthryl group, and an anthracenyl group; a cycloalkenyl group such as a cyclohexenyl group; and 5-bicyclo [2.2. 1] Polycyclic unsaturated alicyclic groups such as a hepta-2-enyl group.

  Examples of the group formed by substituting one or more hydrogen atoms of a saturated hydrocarbon group with a cyclic unsaturated hydrocarbon group include a benzyl group, a cumyl group, a 1,1-diphenylethyl group, and a triphenylmethyl group. And a group formed by substituting one or two or more hydrogen atoms of the alkyl group with an aryl group.

Examples of the hetero atom-containing hydrocarbon group in R ¹ to R ¹⁶ include an alkoxy group such as a methoxy group and an ethoxy group, an aryloxy group such as a phenoxy group, and an oxygen atom-containing hydrocarbon group such as a furyl group; N-methylamino A nitrogen atom-containing hydrocarbon group such as a group, an amino group such as an N, N-dimethylamino group and an N-phenylamino group, and a pyryl group; and a sulfur atom-containing hydrocarbon group such as a thienyl group. Carbon number of a hetero atom containing hydrocarbon group is 1-20 normally, Preferably it is 2-18, More preferably, it is 2-15. However, the silicon-containing group is excluded from the heteroatom-containing hydrocarbon group.

Examples of the silicon-containing group in R ¹ to R ¹⁶ include a formula —SiR ₃ such as a trimethylsilyl group, a triethylsilyl group, a dimethylphenylsilyl group, a diphenylmethylsilyl group, a triphenylsilyl group, and the like. Independently an alkyl group having 1 to 15 carbon atoms or a phenyl group).

Of the substituents from R ¹ to R ¹⁶ , two adjacent substituents (eg, R ¹ and R ² , R ² and R ³ , R ⁴ and R ⁶ , R ⁴ and R ⁷ , R ⁵ and R ⁶⁾ R ⁵ and R ⁷ , R ⁶ and R ⁸ , R ⁷ and R ⁸ , R ⁹ and R ¹⁰ , R ¹⁰ and R ¹¹ , R ¹¹ and R ¹² , R ¹³ and R ¹⁴ , R ¹⁴ and R ¹⁵ , R ¹⁵ and R ¹⁶ ) may be bonded to each other to form a ring, R ⁴ and R ⁵ may be bonded to each other to form a ring, and R ⁶ and R ⁷ may be bonded to each other to form a ring. R ¹ and R ⁸ may be bonded to each other to form a ring, R ³ and R ⁴ may be bonded to each other to form a ring, and R ³ and R ⁵ May be bonded to each other to form a ring. Two or more ring formations may exist in the molecule.

  In this specification, examples of the ring (additional ring) formed by bonding two substituents to each other include an alicyclic ring, an aromatic ring, and a heterocyclic ring. Specific examples include a cyclohexane ring; a benzene ring; a hydrogenated benzene ring; a cyclopentene ring; a hetero ring such as a furan ring and a thiophene ring and a corresponding hydrogenated hetero ring, preferably a cyclohexane ring; a benzene ring and a hydrogen Benzene ring. Such a ring structure may further have a substituent such as an alkyl group on the ring.

R ¹ and R ³ are preferably hydrogen atoms.
R ² is preferably a hydrocarbon group, a heteroatom-containing hydrocarbon group or a silicon-containing group, more preferably a hydrocarbon group, more preferably a hydrocarbon group having 1 to 20 carbon atoms, It is more preferably not an aryl group, particularly preferably a linear hydrocarbon group, a branched hydrocarbon group or a cyclic saturated hydrocarbon group, and a carbon having a free valence (carbon bonded to a cyclopentadienyl ring) ) Is particularly preferably a substituent which is a tertiary carbon.

Specific examples of R ² include a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, a tert-pentyl group, a tert-amyl group, a 1-methylcyclohexyl group, and a 1-adamantyl group. Is a substituent in which the carbon having a free valence is a tertiary carbon, such as a tert-butyl group, a tert-pentyl group, a 1-methylcyclohexyl group, or a 1-adamantyl group, particularly preferably a 1-adamantyl group, tert- It is a butyl group.

At least one selected from R ⁴ , R ⁵ , R ⁶ and R ⁷ is preferably a hydrocarbon group, a heteroatom-containing hydrocarbon group or a silicon-containing group.
More preferably R ⁴ and R ⁵ is a hydrogen atom or a hydrocarbon group, more preferably R ⁵ is a linear alkyl group, alkyl groups such as branched alkyl group, a cycloalkyl group or cycloalkenyl group Particularly preferred is an alkyl group having 1 to 10 carbon atoms. From the viewpoint of synthesis, R ⁴ and R ⁵ are both alkyl groups, and this alkyl group is particularly preferably an alkyl group having 1 to 10 carbon atoms.

Similarly, from the viewpoint of synthesis, R ⁶ and R ⁷ are preferably hydrogen atoms. R ⁵ and R ⁷ are more preferably bonded to each other to form a ring, and the ring is particularly preferably a 6-membered ring such as a cyclohexane ring.

In a preferred embodiment, R ⁴ is a hydrogen atom when the transition metal compound (A) is represented by the following general formula [I ′].

  In this case, the transition metal compound (A) may be any enantiomer of the transition metal compound represented by the general formula [I ′], for example, the general formula [I ″] without departing from the scope of the present invention. The transition metal compound represented by these is included.

In the expressions [I ′] and [I ″], it is assumed that the MQ _j portion is present in front of the paper surface and the bridging portion is present on the back side of the paper surface. That is, in these transition metal compounds, a hydrogen atom (R ⁴ ) directed toward the central metal exists at the α-position of the cyclopentadiene ring (based on the carbon atom substituted with the bridging site).

On the other hand, in the general formula [Ia] described above, it is not specified whether the MQ _j portion and the bridging portion are present on the front side or the back side of the paper surface. That is, the transition metal compound (A) represented by the general formula [Ia] includes a transition metal compound having a specific structure and its enantiomer.

R ⁸ is preferably a hydrocarbon group, and particularly preferably an alkyl group such as a methyl group.
In the general formula [Ia], the fluorene ring moiety is not particularly limited as long as it is a structure obtained from a known fluorene derivative, but R ⁹ , R ¹² , R ¹³ and R ¹⁶ are the molecular weight of the produced propylene polymer. From the viewpoint, a hydrogen atom is preferable.

R ¹⁰ , R ¹¹ , R ¹⁴ and R ¹⁵ are preferably a hydrogen atom, a hydrocarbon group, an oxygen atom-containing hydrocarbon group or a nitrogen atom-containing hydrocarbon group, more preferably a hydrocarbon group, still more preferably It is a C1-C20 hydrocarbon group. Examples of the substituted fluorenyl group constituting the fluorene ring moiety include 2,7-di-tert-butylfluorenyl group, 3,6-di-tert-butylfluorenyl group, and 2,7-diphenyl-3. 1,6-di-tert-butylfluorenyl group, particularly preferably 2,7-di-tert-butylfluorenyl group.

R ¹⁰ and R ¹¹ may be bonded to each other to form a ring, and R ¹⁴ and R ¹⁵ may be bonded to each other to form a ring. Examples of such a substituted fluorenyl group include benzofluorenyl group, dibenzofluorenyl group, octahydrodibenzofluorenyl group, 1,1,4,4,7,7,10,10-octamethyl-2. , 3,4,7,8,9,10,12-octahydro-1H-dibenzo [b, h] fluorenyl group, 1,1,3,3,6,6,8,8-octamethyl-2,3, 6,7,8,10-hexahydro-1H-dicyclopenta [b, h] fluorenyl group, 1 ', 1', 3 ', 6', 8 ', 8'-hexamethyl-1'H, 8'H-dicyclopenta [B, h] fluorenyl group is exemplified, and 1,1,4,4,7,7,10,10-octamethyl-2,3,4,7,8,9,10,12-octahydro- is particularly preferred. A 1H-dibenzo [b, h] fluorenyl group can be mentioned.

<M, Q, j>
M is a Group 4 transition metal, preferably Ti, Zr or Hf, more preferably Zr or Hf, and particularly preferably Zr.

Examples of the halogen atom for Q include fluorine, chlorine, bromine, and iodine.
Examples of the hydrocarbon group for Q include the same groups as the hydrocarbon groups for R ¹ to R ^16, and an alkyl group such as a linear alkyl group or a branched alkyl group is preferable.

  Examples of the anionic ligand for Q include alkoxy groups such as methoxy and tert-butoxy; aryloxy groups such as phenoxy; carboxylate groups such as acetate and benzoate; sulfonate groups such as mesylate and tosylate; dimethylamide and diisopropylamide Amide groups such as methylanilide and diphenylamide.

  Examples of the neutral ligand capable of coordinating with a lone pair in Q include, for example, organophosphorus compounds such as trimethylphosphine, triethylphosphine, triphenylphosphine, diphenylmethylphosphine; tetrahydrofuran, diethyl ether, dioxane, 1,2- Examples include ethers such as dimethoxyethane.

It is preferable that at least one Q is a halogen atom or an alkyl group.
j is preferably 2.
The preferred embodiments of the configuration of the transition metal compound (A) (the compound represented by the general formula [Ia]), that is, R ^{1 to} R ¹⁶ , M, Q, and j have been described above. In the present invention, any combination of the preferred embodiments is also a preferred embodiment.

  Preferred examples of the transition metal compound (A) (compound represented by the general formula [Ia]) include compounds listed on pages 11 to 15 of WO 2006/68308, and WO 2014/50816. Among the compounds listed in [0075]-[0086] of No., and the compounds listed in [0067]-[0078] of WO 2014/142111, The compounds listed in [0072]-[0085] of Kaikai 2008/45008, more specifically, for example, [8- (octamethylfluoren-12′-yl) (2-tert-butyl-8-methyl- 3,3b, 4,5,6,7,7a, 8-octahydrocyclopenta [a] indene)] zirconium dichloride). 1,1,4,4,7,7,10,10-octamethyl-2,3,4,7,8,9,10,12-octahydro-1H-dibenzo [b, h] fluorene was converted to octamethyl It was described as fluorene.

  The transition metal compound (A) (compound represented by the general formula [Ia]) may be a titanium derivative or a hafnium derivative of the compounds exemplified above. However, the transition metal compound (A) is not limited to the compounds exemplified above.

(Compound represented by the general formula [Ib])

<R ²¹ to R ²⁶ and R ³¹ to R ^36>
In the formula [Ib], R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ are each independently a hydrogen atom, carbonized Selected from a hydrogen group, a halogen-containing group, an oxygen-containing group, a nitrogen-containing group, a boron-containing group, a sulfur-containing group, a phosphorus-containing group, a silicon-containing group, a germanium-containing group, and a tin-containing group. It may combine to form a ring.

Examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, and an arylalkyl group.
Examples of the alkyl group include a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, neopentyl group, and n-hexyl group. , N-octyl group, nonyl group, dodecyl group and eicosyl group.

Examples of the cycloalkyl group include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a norbornyl group, and an adamantyl group.
Examples of the alkenyl group include a vinyl group, a propenyl group, and a cyclohexenyl group.

  As the aryl group, for example, phenyl group, tolyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group, propylphenyl group, biphenyl group, α- or β-naphthyl group, methylnaphthyl group, anthracenyl group, phenanthryl group, benzyl Examples thereof include a phenyl group, a pyrenyl group, an acenaphthyl group, a phenalenyl group, an aceantrirenyl group, a tetrahydronaphthyl group, an indanyl group, and a biphenylyl group.

Examples of the arylalkyl group include a benzyl group, a phenylethyl group, and a phenylpropyl group.
Examples of the oxygen-containing group include an alkoxy group, an aryloxy group, an ester group, an ether group, an acyl group, a carboxyl group, a carbonate group, a hydroxy group, a peroxy group, and a carboxylic acid anhydride group.

Among the oxygen-containing groups, preferred examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, and tert-butoxy.
Preferred examples of aryloxy groups include phenoxy, 2,6-dimethylphenoxy, and 2,4,6-trimethylphenoxy,
Preferred examples of ester groups include acetyloxy, benzoyloxy, methoxycarbonyl, phenoxycarbonyl, and p-chlorophenoxycarbonyl,
Preferred examples of the ether group include methoxymethyl group, allyloxymethyl group, phenoxymethyl group, methoxyphenyl group, iso-propoxyphenyl group, allyloxyphenyl group, phenoxyphenyl group, furyl group, methylfuryl group, tetrahydrofuryl group. , Pyranyl group, tetrahydropyranyl group, furfuryl group, benzofuryl group, and dibenzofuryl group,
Preferable examples of the acyl group include formyl group, acetyl group, benzoyl group, p-chlorobenzoyl group, and p-methoxybenzoyl group.

  Examples of the silicon-containing group include a silyl group, a siloxy group, a hydrocarbon-substituted silyl group, and a hydrocarbon-substituted siloxy group. Specific examples of the hydrocarbon-substituted silyl group include methylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl, diethylsilyl, triethylsilyl, diphenylmethylsilyl, triphenylsilyl, dimethylphenylsilyl, dimethyl-t-butylsilyl, dimethyl (pentafluoro Phenyl) silyl and the like. Among these, methylsilyl, dimethylsilyl, trimethylsilyl, ethylsilyl, diethylsilyl, triethylsilyl, dimethylphenylsilyl, triphenylsilyl and the like are preferable. In particular, trimethylsilyl, triethylsilyl, triphenylsilyl, and dimethylphenylsilyl are preferable. Specific examples of the hydrocarbon-substituted siloxy group include trimethylsiloxy and the like.

<Y>
In the formula [Ib], Y is a divalent group that binds two ligands, specifically, a divalent group having 1 to 20 carbon atoms and a halogen-containing group. A group selected from a group, a silicon-containing group, a germanium-containing group, and a tin-containing group, and preferably a divalent hydrocarbon group having 1 to 20 carbon atoms or a divalent silicon-containing group.

Examples of the divalent hydrocarbon group include an alkylene group, a substituted alkylene group, and an alkylidene group. Specific examples thereof include
Alkylene groups such as methylene, ethylene, propylene and butylene;
Isopropylidene, diethylmethylene, dipropylmethylene, diisopropylmethylene, dibutylmethylene, methylethylmethylene, methylbutylmethylene, methyl-t-butylmethylene, dihexylmethylene, dicyclohexylmethylene, methylcyclohexylmethylene, methylphenylmethylene, diphenylmethylene, ditolyl Substituted alkylene groups such as methylene, methylnaphthylmethylene, dinaphthylmethylene, 1-methylethylene, 1,2-dimethylethylene and 1-ethyl-2-methylethylene; and cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexyl Silidene, cycloheptylidene, bicyclo [3.3.1] nonylidene, norbornylidene, adamantylidene, tetrahydronaphthylidene and dihi Examples include cycloalkylidene groups such as droindanilidene and alkylidene groups such as ethylidene, propylidene and butylidene.

As the divalent silicon-containing group,
Silylene; and methylsilylene, dimethylsilylene, diisopropylsilylene, dibutylsilylene, methylbutylsilylene, methyl-t-butylsilylene, dicyclohexylsilylene, methylcyclohexylsilylene, methylphenylsilylene, diphenylsilylene, ditolylsilylene, methylnaphthylsilylene, dinaphthyl Examples include alkylsilylene groups such as silylene, cyclodimethylenesilylene, cyclotrimethylenesilylene, cyclotetramethylenesilylene, cyclopentamethylenesilylene, cyclohexamethylenesilylene and cycloheptamethylenesilylene, and particularly preferred are dimethylsilylene group and dibutylsilylene. And dialkylsilylene groups such as groups.

<M>
In the formula [Ib], M is a Group 4 transition metal atom, preferably Ti, Zr or Hf, more preferably Zr or Hf, and particularly preferably Zr.

<X>
In the formula [Ib], each X is independently selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing hydrocarbon group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, and a phosphorus-containing group. And at least one X, preferably all X are halogen atoms or hydrocarbon groups.

Examples of the halogen atom include fluorine, chlorine, bromine and iodine, and particularly preferably chlorine.
The preferred embodiments of the configuration of the transition metal compound (A) (the compound represented by the general formula [Ib]), that is, R ^{21 to} R ³⁶ , Y, M, and X have been described above. In the present invention, any combination of the preferred embodiments is also a preferred embodiment.

  Preferred examples of the transition metal compound (A) (compound represented by the general formula [Ib]) include compounds listed in [0062], [0073] and [0095] of JP-A-8-225605, The compounds listed in [0077] of Kai 2013-224408 may be mentioned. However, the transition metal compound (A) is not limited to the compounds exemplified above.

<Carrier (B)>
The carrier (B) used in the present invention is a carrier that supports the transition metal compound (A) and includes a structural unit represented by the following formula [II] and has an Al content of 36% by mass or more. The composition (hereinafter also referred to as “solid polyaluminoxane composition (B)”).

  The solid polyaluminoxane composition (B) contains, for example, polyalkylaluminoxane and also contains trialkylaluminum or triarylaluminum (hereinafter also referred to as “trialkylaluminum”), preferably propylene-based heavy. It contains polyalkylaluminoxane and trimethylaluminum containing the structural unit represented by the above formula [II], more preferably polymethylaluminoxane and trimethylaluminum, because the promoter performance for the catalyst for producing the coal is excellent. contains.

  The polyalkylaluminoxane contained in the solid polyaluminoxane composition (B) has the following general formula [III]:

[Wherein, R usually represents a hydrocarbon group having 2 to 20 carbon atoms, preferably a hydrocarbon group having 2 to 15 carbon atoms, and more preferably a hydrocarbon group having 2 to 10 carbon atoms. Indicates. ]
The unit represented by these may be included.

  The structure of polyalkylaluminoxane is not necessarily clarified, and usually has a structure in which the unit represented by the formula [II] and optionally the unit represented by the general formula [III] are repeated about 2 to 50 times. Presumed to contain. Further, the unit connection is various, for example, linear, cyclic or cluster, and polyalkylaluminoxane is usually estimated to be one of these or a mixture thereof. ing.

  Specific examples of the hydrocarbon group as R in the formula [III] include ethyl, propyl, n-butyl, pentyl, hexyl, octyl, decyl, isopropyl, isobutyl, sec-butyl, tert-butyl, 2-methylbutyl, 3 -Methylbutyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 2-methylhexyl, 3-methylhexyl, 2-ethylhexyl, cyclohexyl, cyclooctyl, phenyl, tolyl.

  Examples of the trialkylaluminum include trimethylaluminum having a methyl group, trialkylaluminum having a hydrocarbon group having 2 to 20 carbon atoms, and triarylaluminum.

Specific examples of the trialkylaluminum having a hydrocarbon group having 2 to 20 carbon atoms include triethylaluminum, tri (n-butyl) aluminum, tripropylaluminum, tripentylaluminum, trihexylaluminum, trioctylaluminum, tridecyl Tri (n-alkyl) aluminum such as aluminum;
Triisopropylaluminum, triisobutylaluminum, tri (sec-butyl) aluminum, tri (tert-butyl) aluminum, tri (2-methylbutyl) aluminum, tri (3-methylbutyl) aluminum, tri (2-methylpentyl) aluminum, tri Tri-branched alkyl aluminums such as (3-methylpentyl) aluminum, tri (4-methylpentyl) aluminum, tri (2-methylhexyl) aluminum, tri (3-methylhexyl) aluminum, tri (2-ethylhexyl) aluminum;
And tricycloalkylaluminum such as tricyclohexylaluminum and tricyclooctylaluminum.

Examples of triaryl aluminum include triphenyl aluminum and tolyl aluminum.
As the trialkylaluminum, a trialkylaluminum having any alkyl group can be used regardless of the type of polyalkylaluminoxane. Among these, trimethylaluminum is preferable from the viewpoint of activity as a cocatalyst and raw material procurement.

  Examples of the solid polyaluminoxane composition (B) include solid polyaluminoxane compositions disclosed in International Publication No. 2010/055562 and International Publication No. 2014/123212.

In the method for producing a propylene-based polymer of the present invention, the carrier is not a carrier made of SiO ₂ (hereinafter, also referred to as “silica carrier”), which is often used as a carrier, but an aluminum content of 36% by mass or more. The solid polyaluminoxane composition (B) is used. According to the method for producing a propylene-based polymer of the present invention using a carrier comprising a transition metal compound (A) and a solid polyaluminoxane composition (B) having an aluminum content of 36% by mass or more, the same transition metal compound (A ) And a propylene polymer having a high molecular weight can be produced as compared with the case where a conventional method for producing a propylene polymer using a silica carrier is carried out. The reason for this is not necessarily clear, but if a carrier having a high aluminum content is used, the structure of the cation complex species formed from the transition metal compound and aluminum as the promoter component, such as the distance between the promoter and the cation complex, etc. It is conceivable that the insertion reaction of the monomer into the polymer chain is promoted and / or the rate of chain transfer to the monomer is reduced, contributing to the improvement of the molecular weight. This effect is obtained when each of the various transition metal compounds (A) represented by the formula [Ia] or [Ib] is used. That is, when a polymerization catalyst obtained by supporting a transition metal compound (A) on the carrier (B) is used, a polymerization catalyst obtained by supporting the same transition metal compound (A) on a silica carrier is used. A higher molecular weight propylene polymer can be obtained than in the case.

  The aluminum content of the solid polyaluminoxane composition (B) varies depending on the structure of polyaluminoxane and trialkylaluminum and the ratio of polyaluminoxane and trialkylaluminum in the solid polyaluminoxane composition (B). From the above viewpoint, the aluminum content is 36% by mass or more, preferably 40% by mass or more, more preferably 41% by mass or more, and particularly preferably 42% by mass or more. The upper limit may be 47% by mass, for example.

The solid polyaluminoxane composition (B) preferably satisfies the following requirements (i) and (ii).
Requirement (i): The solubility in n-hexane at 25 ° C. measured by the following method (i) is less than 2.0 mol%, preferably 1.0 mol% or less, more preferably 0.50 mol% or less, Especially preferably, it is 0.30 mol% or less.

  Requirement (ii): The solubility in toluene at 25 ° C. measured by the following method (ii) is less than 2.0 mol%, preferably 1.0 mol% or less, more preferably 0.50 mol% or less, particularly preferably Is 0.30 mol% or less.

[Method (i)]
2 g of a solid polyaluminoxane composition is added to 50 mL of n-hexane maintained at 25 ° C., followed by stirring for 2 hours, followed by separation into a filtrate and a residue by filtration, and the concentration of aluminum in the filtrate Is measured using ICP emission spectroscopy (ICP-AES), and the solubility is determined as the ratio of aluminum atoms present in the filtrate to the amount of aluminum atoms corresponding to 2 g of the solid polyaluminoxane composition.

[Method (ii)]
Solubility is calculated | required by the method similar to the said method (i) except having used toluene instead of n-hexane. Specifically, the solubility is such that 2 g of solid polyaluminoxane composition is added to 50 mL of toluene maintained at 25 ° C., followed by stirring for 2 hours, followed by filtration to separate the filtrate and the residue, The aluminum concentration in the filtrate was measured using ICP emission spectroscopy (ICP-AES), and the ratio of aluminum atoms present in the filtrate to the amount of aluminum atoms corresponding to 2 g of the solid polyaluminoxane composition was measured. Determine solubility.

  The solid polyaluminoxane composition (B) used in the present invention preferably has low solubility in n-hexane and toluene maintained at 25 ° C. In the propylene polymerization reaction step and / or the catalyst preparation step, the elution of the cocatalyst component, the main catalyst component, or the reaction composition of the main catalyst component and the cocatalyst component into the reaction solvent produces an amorphous propylene polymer. This contributes to fouling in a polymerization reactor or the like. Therefore, the composition has low solubility in an aliphatic hydrocarbon solvent typified by n-hexane and an aromatic hydrocarbon solvent typified by toluene used in a propylene polymerization reaction step and / or a catalyst preparation step thereof. Moderately good.

The solid polyaluminoxane composition (B) is preferably in the form of particles and has a specific surface area of 400 to 900 m ² / g. It is known that the specific surface area of the carrier greatly affects the catalyst activity in the olefin polymerization reaction. If the specific surface area is small, the activation efficiency of the transition metal complex serving as the main catalyst decreases, and the catalytic activity decreases. There is a fear. On the other hand, if the specific surface area is too high, since the pore diameter of the support is generally small, the transition metal complex as the main catalyst may not be uniformly supported on the support. From the above, the specific surface area is preferably in the range of 400~900m ² / g, and more preferably in the range of 420~800m ² / g. The specific surface area can be determined using the BET adsorption isotherm and utilizing the gas adsorption and desorption phenomena on the solid surface.

  The solid polyaluminoxane composition (B) in the form of particles preferably has a volume-based median diameter (median diameter, D50) in the range of 0.1 to 100 μm. When used as a propylene polymerization (multiplication) catalyst component, if the average particle size is larger than 100 μm, a large amount of coarse polymer particles are produced, which may cause troubles such as blockage of a polymer discharge port and a polymer transfer line. On the other hand, when the average particle size is smaller than 0.1 μm, a lot of fine polymer particles are generated, and not only the problem of charging due to static electricity is likely to occur, but also production efficiency is lowered due to deterioration of sedimentation property and filterability. Problems may occur. From the above, the volume-based median diameter (median diameter, D50) is preferably in the range of 0.1 to 100 μm, more preferably in the range of 0.5 to 80 μm, and still more preferably 1.0. It is in the range of ˜60 μm, and particularly preferably in the range of 5.0 to 55 μm. The volume-based median diameter (median diameter, D50) can be obtained by a laser diffraction / scattering method using, for example, MT3300EX II manufactured by Microtrac. The specific method is described in the test examples.

International Publication No. 2010/055562 describes an index representing the uniformity of the particle diameter of a particulate solid polyaluminoxane composition represented by the following formula.
Uniformity index = ΣXi | D50−Di | / D50ΣXi
[Xi is a histogram value of particle i in particle size distribution measurement, D50 is a volume-based median diameter, and Di is a volume-based diameter of particle i. ]
In this index, the larger the value, the wider the distribution.

  In the production method of the present invention, from the viewpoint of stable operation of the polymerization step, the solid polyaluminoxane composition (B) preferably has a narrow particle size distribution, and the uniformity index is preferably 0.45 or less, Preferably it is 0.40 or less, Most preferably, it is 0.27 or less. Considering that the solid polyaluminoxane composition (B) is formed into particles by self-association, the lower limit of the uniformity index may be, for example, 0.15.

  The carrier (B) preferably contains no solid carrier other than the solid polyaluminoxane composition (B). Examples of solid carriers other than the solid polyaluminoxane composition (B) include solid inorganic carriers such as silica, alumina, silica-alumina, and magnesium chloride, and solid organic carriers such as polystyrene beads.

[Propylene polymerization catalyst]
The catalyst for propylene polymerization used in the present invention contains the transition metal compound (A) and the carrier (B). The transition metal compound (A) is supported on the carrier (B).

The propylene polymerization catalyst further includes:
(C) At least one compound selected from (C-1) an organometallic compound and (C-2) an organoaluminum oxy compound (hereinafter also referred to as “compound (C)”).
It is preferable to contain.

Hereinafter, the compound (C) will be specifically described.
<Compound (C)>
《Organic metal compound (C-1)》
Examples of the organometallic compound (C-1) include an organoaluminum compound (C-1a) represented by the general formula (C-1a), a Group 1 metal represented by the general formula (C-1b), and aluminum. A complex alkylated product (C-1b), a dialkyl compound (C-1c) of a group 2 or group 12 metal represented by the general formula (C-1c), Examples include Group 13 organometallic compounds.

_{(C-1a): Ra m} Al (ORb) n H p X q
In formula (C-1a), Ra and Rb are each independently a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, X is a halogen atom, m is 0 <m ≦ 3, and n is 0 ≦ n <3, p is a number satisfying 0 ≦ p <3, q is a number satisfying 0 ≦ q <3, and m + n + p + q = 3. Examples of the organoaluminum compound (C-1a) include trialkylaluminum such as trimethylaluminum, triethylaluminum, and triisobutylaluminum, dialkylaluminum hydride such as diisobutylaluminum hydride, and tricycloalkylaluminum.

(C-1b): M2AlRa ₄
In formula (C-1b), M2 is Li, Na or K, and Ra is a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms. Examples of the complex alkylated product (C-1b) include LiAl (C ₂ H ₅ ) ₄ and LiAl (C ₇ H ₁₅ ) ₄ .

(C-1c): RaRbM3
In formula (C-1c), Ra and Rb are each independently a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms, and M3 is Mg, Zn or Cd. Examples of the compound (C-1c) include dimethyl magnesium, diethyl magnesium, di n-butyl magnesium, ethyl n-butyl magnesium, diphenyl magnesium, dimethyl zinc, diethyl zinc, di n-butyl zinc, and diphenyl zinc.

Of the organometallic compounds (C), organoaluminum compounds (C-1a) are preferred.
An organometallic compound (C) may be used individually by 1 type, and may use 2 or more types together.

《Organic aluminum oxy compound (C-2)》
The organoaluminum oxy compound (C-2) may be, for example, a conventionally known aluminoxane, which is insoluble or hardly soluble in benzene as exemplified in JP-A-2-78687. It may be a compound. A conventionally well-known aluminoxane can be manufactured, for example by the method of following (1)-(4), and is normally obtained as a solution of a hydrocarbon solvent.

  (1) A compound containing adsorbed water or a salt containing water of crystallization, such as magnesium chloride hydrate, copper sulfate hydrate, aluminum sulfate hydrate, nickel sulfate hydrate, first cerium chloride hydrate A method of reacting adsorbed water or crystal water with an organoaluminum compound by adding an organoaluminum compound such as trialkylaluminum to a hydrocarbon medium suspension such as

  (2) A method in which water, ice or water vapor is directly applied to an organoaluminum compound such as trialkylaluminum in a medium such as benzene, toluene, diethyl ether or tetrahydrofuran.

  (3) A method in which an organotin oxide such as dimethyltin oxide or dibutyltin oxide is reacted with an organoaluminum compound such as trialkylaluminum in a medium such as decane, benzene, or toluene.

  (4) Non-hydrolytic conversion such as thermal decomposition of compounds produced by reacting organic aluminum such as trialkylaluminum with organic compounds having carbon-oxygen bonds such as alcohols, ketones and carboxylic acids. how to.

  The aluminoxane may contain a small amount of an organometallic component. Alternatively, the solvent or the unreacted organoaluminum compound may be removed by distillation from the recovered aluminoxane solution, and then redissolved in a solvent or suspended in a poor aluminoxane solvent.

  Specific examples of the organoaluminum compound used in preparing the aluminoxane include the same organoaluminum compounds as those exemplified as the organoaluminum compound (C-1a). Among these, trialkylaluminum and tricycloalkylaluminum are preferable, and trimethylaluminum is particularly preferable.

  Other examples of the organoaluminum oxy compound (C-2) include modified methylaluminoxane. Modified methylaluminoxane is an aluminoxane prepared using trimethylaluminum and an alkylaluminum other than trimethylaluminum. Such a compound is generally called MMAO. MMAO can be prepared by the methods listed in US Pat. No. 4,960,878 and US Pat. No. 5,041,584. In addition, aluminoxanes prepared by using trimethylaluminum and triisobutylaluminum from Tosoh Finechem Co., Ltd. and having R as an isobutyl group are commercially produced under the names MMAO and TMAO.

  Such MMAO is an aluminoxane having improved solubility in various solvents and storage stability. Specifically, unlike MMAO, which is insoluble or hardly soluble in benzene, aliphatic hydrocarbons and It has the feature of being soluble in alicyclic hydrocarbons.

Furthermore, as the organoaluminum oxy compound (C-2), for example, an organoaluminum oxy compound containing a boron atom, and halogens exemplified in International Publication No. 2005/066191 and International Publication No. 2007/131010 are used. Examples of the aluminoxane include ionic aluminoxane as exemplified in International Publication No. WO2003 / 082879.
A compound (C-2) may be used individually by 1 type, and may use 2 or more types together.

<Usage and order of addition of each component>
In the case of propylene polymerization, the usage method and order of addition of each component are arbitrarily selected, and the following methods are exemplified. Hereinafter, the transition metal compound (A), the carrier (B), and the compound (C) are also referred to as “components (A) to (C)”.
(1) A method in which a catalyst component carrying component (A) on component (B) is added to a polymerization vessel.
(2) a catalyst component supported on component (A) and component (B);
A method of adding the component (C) to the polymerization vessel in an arbitrary order.
(3) A method in which a catalyst component in which component (A) and component (C) are supported on component (B) is added to the polymerization vessel.

In each of the above methods, at least two of the catalyst components may be contacted in advance.
In the method (3) in which the component (C) is supported, the unsupported component (C) may be added in any order as necessary. In this case, the component (C) may be the same or different. In the solid catalyst component in which the component (B) is supported on the component (B) and the solid catalyst component in which the component (A) and the component (C) are supported on the component (B), propylene is prepolymerized. Alternatively, a catalyst component may be further supported on the prepolymerized solid catalyst component.

  The method of supporting component (A) or component (C) on component (B) is not particularly limited as long as the effects of the present invention are exhibited, but it is preferable to support component (B) in a state dispersed in a solvent. .

  Examples of the solvent include polar solvents, aromatic solvents, and hydrocarbon solvents, and aromatic solvents or hydrocarbon solvents are particularly preferable. Examples of the polar solvent include diethyl ether, tetrahydrofuran, dioxane, cyclopentyl methyl ether and the like. Examples of the aromatic solvent include benzene, toluene, xylene, mesitylene and the like. Examples of the hydrocarbon solvent include pentane, hexane, heptane, octane, nonane, decane, dodecane, cyclopentane, cyclohexane, and methylcyclopentane. Two or more solvents may be mixed and used in an arbitrary ratio.

  Although the temperature at the time of carrying a component (A) and a component (C) to a component (B) is not specifically limited, Usually, it is -50 degreeC-120 degreeC, Preferably it is -20 degreeC-100 degreeC, Most preferably It is 0 degreeC-70 degreeC.

  The ratio of the component (A) based on the mass of the propylene polymerization catalyst [that is, the mass of the component (A) (g) / the mass of the propylene polymerization catalyst (g) × 100 (% by mass)] is 0.00. It can be used in an amount of 01 to 50% by mass, preferably 0.01 to 30% by mass, more preferably 0.1 to 20% by mass, and most preferably 0.5 to 10% by mass.

[Propylene-based polymer production method]
The method for producing a propylene polymer of the present invention includes a step of polymerizing propylene in the presence of the propylene polymerization catalyst (polymerization step). In addition, “polymerize propylene in the presence of a catalyst for propylene polymerization” means that each component of the catalyst for propylene polymerization is added to the polymerization vessel by any method as in the above methods (1) to (3). And an embodiment in which propylene is polymerized.

  In the polymerization step, preferably only propylene is polymerized, but a small amount of other monomers may be polymerized (copolymerized) together with propylene. Other monomers include ethylene and α-olefins having 4 to 30 carbon atoms such as 1-butene, 2-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene. , 3-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene and 1-icocene.

  In the present invention, the polymerization can be carried out by either a liquid phase polymerization method such as solution polymerization or suspension polymerization or a gas phase polymerization method. Examples of the inert hydrocarbon medium used in the liquid phase polymerization method include aliphatic hydrocarbons such as propane, butane, pentane, hexane, heptane, octane, decane, dodecane, and kerosene; cyclopentane, cyclohexane, methylcyclopentane, and the like. And alicyclic hydrocarbons; aromatic hydrocarbons such as benzene, toluene and xylene; and halogenated hydrocarbons such as ethylene chloride, chlorobenzene and dichloromethane. An inert hydrocarbon medium may be used individually by 1 type, and 2 or more types may be mixed and used for it. In particular, a so-called bulk polymerization method using liquefied propylene itself that can be supplied to the polymerization as a solvent is preferable.

When propylene is polymerized using the propylene polymerization catalyst, the amount of each component that can constitute the propylene polymerization catalyst is as follows.
Component (A) is generally used in an amount of 10 ⁻¹⁰ to 10 ⁻² mol, preferably 10 ⁻⁹ to 10 ⁻³ mol, per liter of reaction volume. Component (C-1) has a molar ratio [(C-1) / M] of component (C-1) to all transition metal atoms (M) in component (A) of usually 1 to 50,000, preferably Can be used in an amount of 10 to 20,000, particularly preferably 50 to 10,000. Component (C-2) has a molar ratio [Al / M] of aluminum atoms in component (C-2) to all transition metal atoms (M) in component (A) of usually 10 to 30,000, preferably Can be used in an amount of 20 to 10,000.

  In the production method of the present invention, the polymerization temperature in the polymerization step is usually −50 to + 200 ° C., preferably 0 to 180 ° C .; the polymerization pressure is usually normal pressure to 10 MPa gauge pressure, preferably normal pressure to 5 MPa gauge. Pressure. The polymerization reaction can be carried out in any of batch, semi-continuous and continuous methods. Furthermore, the polymerization can be carried out in two or more stages having different reaction conditions. The molecular weight of the resulting propylene polymer can be adjusted by allowing hydrogen or the like to be present in the polymerization system, changing the polymerization temperature, or using the component (C).

  In particular, hydrogen can be said to be a preferable additive because it can improve the polymerization activity of the catalyst and increase or decrease the molecular weight of the polymer. When hydrogen is added to the system, the amount is suitably about 0.00001 to 100 NL per mole of propylene. In addition to adjusting the amount of hydrogen supplied, the hydrogen concentration in the system is not limited to the method of generating or consuming hydrogen in the system, the method of separating hydrogen using a membrane, It can also be adjusted by releasing the gas out of the system.

  The production method of the present invention may be carried out by adding an antistatic agent to the system during the polymerization. Antistatic agents include polypropylene glycol, polypropylene glycol distearate, ethylenediamine-PEG-PPG-block copolymer, stearyl diethanolamine, lauryl diethanolamine, alkyldiethanolamide, polyoxyalkylene (eg polyethylene glycol, polypropylene glycol, polyethylene glycol block copolymer) For example, polyoxyalkylene (PEG-PPG-PEG) is preferable. In these antistatic agents, the ratio (g / mol) of the mass (g) to 1 mol of the transition metal atom (M) in the transition metal compound (A) is usually 100 to 10,000, preferably 100 to 1,000. Used in various amounts.

  For the propylene polymer obtained by the production method of the present invention, after synthesizing by the above method, a post-treatment step such as a known catalyst deactivation treatment step, a catalyst residue removal step, and a drying step is performed as necessary. You can go.

[Propylene polymer]
The propylene polymer produced by the production method of the present invention is preferably a propylene homopolymer. The propylene-based polymer may contain a small amount of a structural unit derived from the other monomer other than propylene (that is, it may be a copolymer containing propylene as a main component), but is derived from another monomer. The content of the structural unit is preferably 5 mol% or less, more preferably less than 1 mol%, still more preferably 0.1 mol% or less. However, the total of the content of the structural unit derived from propylene and the content of the structural unit derived from the other monomer is 100 mol%. These contents can be measured by nuclear magnetic resonance spectroscopy or, if there is a reference substance, infrared spectroscopy.

  In the propylene polymer, the weight average molecular weight measured by a gel permeation chromatography (GPC) method is preferably 5,000 to 5,000,000, more preferably 10,000 to 3,000,000, particularly preferably 10,000 to 200. Ten thousand. The molecular weight distribution (Mw / Mn), which is the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn), is preferably 1.0 to 10.0, more preferably 1.0 to 8.0, particularly preferably. Is 1.5 to 6.0.

  In the propylene-based polymer, the intrinsic viscosity [η] is preferably 0.1 to 12 dl / g, more preferably 0.1 to 10 dl / g, and still more preferably 0.2 to 8 dl / g.

EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to these Examples.
[Measurement methods for various physical properties]
Intrinsic viscosity ([η])
Using an automatic kinematic viscosity measuring device VMR-053PC and a modified Ubbelohde type capillary viscometer manufactured by Kouaisha Co., Ltd., decalin and specific viscosity ηsp at 135 ° C. were determined, and the intrinsic viscosity ([η]) was calculated from the following formula.
[Η] = ηsp / {C (1 + K · ηsp)} (C: solution concentration [g / dl], K: constant)

Zirconium content in supported catalyst The zirconium content in the supported catalyst was measured using an ICP emission spectroscopic analyzer (ICPS-8100 type) manufactured by Shimadzu Corporation. The sample was wet-decomposed with sulfuric acid and nitric acid, and then a fixed volume (including filtration and dilution as necessary) was used as a test solution, and quantification was performed from a calibration curve prepared using a standard sample with a known concentration.

Aluminum content in the carrier The aluminum content in the carrier was measured by subjecting the carrier particles to ICP emission spectroscopy (ICP-AES) using ICPS (registered trademark) -8100 manufactured by Shimadzu Corporation.

Solubility of carrier When a solid polyaluminoxane composition is used as a carrier, the solubility of the solid polyaluminoxane composition in n-hexane, toluene and tetrahydrofuran at 25 ° C is measured by the method described in JP-B-7-42301 It carried out according to. Specifically, the solubility of the dried solid polyaluminoxane composition in the solvent was measured.

The solubility in each solvent such as n-hexane was measured as follows. First, 2 g of the solid polyaluminoxane composition is added to 50 mL of each solvent kept at 25 ° C., followed by stirring for 2 hours, followed by separation of the solution portion using a G-4 glass filter. The aluminum concentration in the filtrate was measured. The dissolution ratio obtained by this method was determined as the ratio of aluminum atoms present in the filtrate to the amount of aluminum atoms corresponding to 2 g of the solid polyaluminoxane composition used as a sample. The solubility of toluene was measured by replacing the hexane with toluene.
In addition, when drying a solid polyaluminoxane composition, it dried under reduced pressure at 25 degreeC and made the end point of drying the time when a weight change was not recognized.

Volume-based median diameter (D50) and particle size distribution of the support The volume-based median diameter (median diameter, D50) and particle size distribution of the solid polyaluminoxane composition were measured using a Microtrac MT3300EX II manufactured by Microtrac. -Determined by scattering method. For the particle size distribution measurement, a sample in which the solid polyaluminoxane composition was previously deactivated in a wet desiccator under nitrogen flow was used. Methanol was mainly used as the dispersion medium.

Uniformity of carrier particles The uniformity of carrier particles was evaluated by the uniformity index represented by the following formula.
Uniformity index = ΣXi | D50−Di | / D50ΣXi
[Wherein, Xi represents a histogram value of particle i in particle size distribution measurement, D50 represents a volume-based median diameter, and Di represents a volume-based diameter of particle i. ]
Xi, D50 and Di of the carrier particles were measured by a laser diffraction / scattering method using MT3300EX II manufactured by Microtrac.

For the measurement, a sample in which the solid polyaluminoxane composition was previously deactivated in a wet desiccator under nitrogen flow was used. Methanol was mainly used as the dispersion medium.
Unless otherwise specified, all examples were performed using a dry solvent under a dry nitrogen atmosphere.

[Synthesis of transition metal compounds]
[Synthesis Example 1]
(8-octamethylfluoren-12'-yl- (2-tert-butyl-8-methyl-3,3b, 4,5,6,7,7a, 8-octahydrocyclopenta [a] indene)) zirconium Synthesis of dichloride (hereinafter also referred to as “catalyst A”)
According to Example 5B of WO2014 / 050816, a catalyst A composed of a transition metal compound represented by the following formula (including its enantiomer) was synthesized (in the formula below, the ZrCl ₂ portion was in front of the paper surface and the cross-linked portion was Suppose that it exists on the back side of the page.) 1,1,4,4,7,7,10,10-Octamethyl-2,3,4,7,8,9,10,12-octahydro-1H-dibenzo [b, h] fluorene "Methylfluorene".

[Synthesis Example 2]
[3- (2 ', 7'-di-tert-butylfluorenyl) (1,1,3-trimethyl-5- (1-adamantyl) -1,2,3,3a-tetrahydropentalene)] zirconium Synthesis of Dichloride (hereinafter also referred to as “Catalyst B”) According to Synthesis Example 2 of WO2014 / 142111, Catalyst B comprising a transition metal compound represented by the following formula was synthesized.

[Synthesis Example 3]
(8-octamethylfluoren-12'-yl- (2- (adamantan-1-yl) -8-methyl-3,3b, 4,5,6,7,7a, 8-octahydrocyclopenta [a] Indene)) Synthesis of zirconium dichloride (hereinafter also referred to as “catalyst C”) In accordance with Synthesis Example 4 of WO2014 / 050817, a catalyst C comprising a transition metal compound represented by the following formula (including its enantiomer) Synthesized (assuming that the ZrCl ₂ portion is present in front of the paper surface and the bridging portion is present on the back side of the paper surface).

[Synthesis Example 4]
[3-octamethylfluoren-12′-yl- (1,1,3-trimethyl-5-tert-butyl-1,2,3,3a-tetrahydropentalene)] zirconium dichloride (hereinafter also referred to as “catalyst D”) In accordance with Comparative Synthesis Example 1 of WO2014 / 050817, a catalyst D composed of a transition metal compound represented by the following formula was synthesized.

[Synthesis Example 5]
Synthesis of rac-dimethylsilylbis (2-methyl-4- phenylindenyl ) zirconium dichloride (hereinafter also referred to as “catalyst E”) according to the description in [0085] to [0091] of Synthesis Patent No. 3737134 Catalyst E comprising a transition metal compound was synthesized.

(Preparation of supported catalyst)
[Preparation Example 1]
The solid polyaluminoxane composition to be used was prepared based on a known method (International Publication No. 2014/123212). Specifically, after adding 57 mL of toluene and 20 wt% polymethylaluminoxane toluene solution (Al concentration = 3.04 mmol / mL, 35 mL, 106.3 mmol) manufactured by Albemarle to a 200 mL glass flask equipped with a stirrer, the mixture was stirred. The temperature was raised to 70 ° C. Subsequently, a toluene solution (18.6 mL) of acetophenone (1.79 g, 14.9 mmol) was added over 120 minutes. After the addition, the mixture was stirred at 70 ° C. for 60 minutes, heated to 95 ° C. at a rate of temperature increase of 1.0 ° C./min, and reacted at 95 ° C. for 8 hours. After cooling to 80 ° C., the supernatant (75 mL) was removed by decantation. The precipitated solid polyaluminoxane was washed three times at 80 ° C. with toluene (45 mL), and then toluene was added to adjust the total amount to 100 mL to obtain a toluene slurry of the solid polyaluminoxane composition. The obtained slurry was filtered and the powder on the filter was washed 3 times with 20 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 6 hours to obtain a solid polyaluminoxane composition. When the aluminum content in the obtained solid polyaluminoxane composition was measured, the aluminum content was 44.4% by mass.

  The solubility of the obtained solid polyaluminoxane composition in the solvent was measured. The solubility in n-hexane at 25 ° C. was less than 0.04 mol%, and the solubility in toluene was less than 0.05 mol%.

Further, the particle size distribution was measured. The volume-based median diameter (D50) was 29.7 μm, and the uniformity index was 0.236.
Next, a stirring bar was attached to a 100 mL three-necked flask thoroughly purged with nitrogen, and 0.505 g of the above-described solid polyaluminoxane composition and 20 mL of dehydrated toluene were added thereto. To this was added 5.4 mL of a toluene solution containing 26.9 mg of Catalyst A obtained in Synthesis Example 1, and the mixture was stirred at room temperature for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed once with 10 mL of dehydrated toluene and then 3 times with 10 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.509 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 9.95 wt%.

[Preparation Example 2]
The solid polyaluminoxane composition to be used was prepared based on a known method (International Publication No. 2014/123212). Specifically, 55 mL of toluene and a 20 wt% polymethylaluminoxane toluene solution (Al concentration = 2.97 mmol / mL, 192 mL, 570.2 mmol) manufactured by Albemarle were added to a 1 L glass autoclave equipped with a stirrer, and then stirred. The temperature was raised to 70 ° C. Subsequently, a toluene solution (24.5 mL) of benzaldehyde (9.10 g, 85.8 mmol) was added over 80 minutes. After the addition, the mixture was stirred at 70 ° C. for 10 minutes, then heated to 140 ° C. at a rate of 1.0 ° C./min, and reacted at 140 ° C. for 4 hours. After cooling to 80 ° C., the supernatant (125 mL) was removed by decantation. The precipitated solid polyaluminoxane was washed twice with toluene (400 mL) at 80 ° C., and then toluene was added to adjust the total amount to 300 mL to obtain a toluene slurry of the solid polyaluminoxane composition.

  The obtained slurry was filtered and the powder on the filter was washed 3 times with 20 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 6 hours to obtain a solid polyaluminoxane composition. When the aluminum content in the obtained solid polyaluminoxane composition was measured, the aluminum content was 43.3% by mass.

  The solubility of the obtained solid polyaluminoxane composition in the solvent was measured. The solubility in n-hexane at 25 ° C. was less than 0.05 mol%, and the solubility in toluene was less than 0.05 mol%.

Further, the particle size distribution was measured. The volume-based median diameter (D50) was 22.7 μm, and the uniformity index was 0.278.
Next, a toluene slurry (Al concentration = 1.65 mmol / mL, 2.45 mL, 4.05 mmol) of the solid polymethylaluminoxane composition and 16.5 mL of toluene were collected in a reactor. To this was added 1.00 mL of a toluene solution containing 10.0 mg of the catalyst B obtained in Synthesis Example 2, and the mixture was stirred at room temperature for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed twice with 5 mL of dehydrated toluene and then twice with 5 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.235 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 5.00 wt%.

[Preparation Example 3]
The toluene slurry (Al concentration = 1.65 mmol / mL, 2.45 mL, 4.05 mmol) of the solid polymethylaluminoxane composition obtained in Preparation Example 2 and 16.5 mL of toluene were collected in a reactor. To this was added 1.00 mL of a toluene solution containing 10.0 mg of Catalyst C obtained in Synthesis Example 3, and the mixture was stirred at room temperature for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed twice with 5 mL of dehydrated toluene and then twice with 5 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.244 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 4.94 wt%.

[Preparation Example 4]
The toluene slurry (Al concentration = 1.65 mmol / mL, 2.45 mL, 4.05 mmol) of the solid polymethylaluminoxane composition obtained in Preparation Example 2 and 16.5 mL of toluene were collected in a reactor. To this was added 1.00 mL of a toluene solution containing 10.0 mg of the catalyst D obtained in Synthesis Example 4, and the mixture was stirred at room temperature for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed twice with 5 mL of dehydrated toluene and then twice with 5 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.241 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 4.99 wt%.

[Preparation Example 5]
The solid polyaluminoxane composition to be used was prepared based on a known method (International Publication No. 2014/123212). Specifically, 83 mL of toluene and a 20 wt% polymethylaluminoxane toluene solution (Al concentration = 3.01 mmol / mL, 167 mL, 502.7 mmol) manufactured by Albemarle were added to a 1 L glass autoclave equipped with a stirrer, and then stirred. The temperature was raised to 70 ° C. Subsequently, a toluene solution (21.5 mL) of 2-phenyl-2-propanol (10.2 g, 75.3 mmol) was added over 80 minutes. After the addition, the mixture was stirred at 70 ° C. for 10 minutes, then heated to 140 ° C. at a rate of 1.0 ° C./min, and reacted at 140 ° C. for 4 hours. After cooling to 80 ° C., the supernatant (125 mL) was removed by decantation. The precipitated solid polyaluminoxane was washed twice with toluene (400 mL) at 80 ° C., and then toluene was added to adjust the total amount to 300 mL to obtain a toluene slurry of the solid polyaluminoxane composition.

  The obtained slurry was filtered and the powder on the filter was washed 3 times with 20 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 6 hours to obtain a solid polyaluminoxane composition. When the aluminum content in the obtained solid polyaluminoxane composition was measured, the aluminum content was 44.3% by mass.

  The solubility of the obtained solid polyaluminoxane composition in the solvent was measured. The solubility in n-hexane at 25 ° C. was less than 0.05 mol%, and the solubility in toluene was less than 0.05 mol%.

Further, the particle size distribution was measured. The volume-based median diameter (D50) was 26.9 μm, and the uniformity index was 0.229.
Next, a toluene slurry (Al concentration = 1.77 mmol / mL, 2.30 mL, 4.06 mmol) of the solid polymethylaluminoxane composition and 16.7 mL of toluene were collected in a reactor. To this was added 1.00 mL of a toluene solution containing 10.0 mg of the catalyst B obtained in Synthesis Example 2, and the mixture was stirred at room temperature for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed twice with 5 mL of dehydrated toluene and then twice with 5 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.227 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 5.01 wt%.

[Preparation Example 6]
The toluene slurry (Al concentration = 1.77 mmol / mL, 2.30 mL, 4.06 mmol) of the solid polymethylaluminoxane composition obtained in Preparation Example 5 and 16.7 mL of toluene were collected in a reactor. To this was added 1.00 mL of a toluene solution containing 10.0 mg of Catalyst C obtained in Synthesis Example 3, and the mixture was stirred at room temperature for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed twice with 5 mL of dehydrated toluene and then twice with 5 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.214 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 4.99 wt%.

[Preparation Example 7]
0.4995 g of the solid polymethylaluminoxane composition obtained in Preparation Example 1 and 30 mL of toluene were collected in a reactor. To this, 3.0 mL of a toluene solution containing 22.1 mg of the catalyst E obtained in Synthesis Example 5 was added, and the mixture was stirred at 35 ° C. for 1 hour. The resulting slurry was filtered, and the powder on the filter was washed twice with 10 mL of dehydrated toluene and then twice with 10 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.458 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 10.0 wt%.

[Comparative Preparation Example 1]
Silica-supported methylaluminoxane was obtained by the method described in WO 2014/050816 [0253]. The Al concentration in the silica-supported methylaluminoxane was 18.0% by mass.

  A stirring bar was attached to a 100 mL three-necked flask sufficiently purged with nitrogen, and 0.588 g of silica-supported methylaluminoxane (Al = 18.0% by mass) was added thereto. To this, 27.4 mL of dehydrated toluene was added at room temperature, and 2.64 mL of a toluene solution containing 13.2 mg of Catalyst A obtained in Synthesis Example 1 was added with stirring, followed by stirring for 1 hour. The obtained slurry was filtered, and the powder on the filter was washed once with 10 mL of dehydrated toluene and then 3 times with 10 mL of dehydrated hexane. The washed powder was dried under reduced pressure for 2 hours to obtain a supported catalyst composed of 0.4175 g of powder. This was mixed with mineral oil to obtain a slurry having a supported catalyst concentration of 9.98 wt%.

[Propylene polymerization]
[Example 1]
A mixture of 612 mg of the supported catalyst slurry prepared in Preparation Example 1 and 1.5 mL of a hexane solution of triisobutylaluminum (Al = 0.5 M) was charged into a 3.4-liter SUS autoclave sufficiently purged with nitrogen. did. Next, 750 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

[Comparative Example 1]
The same operation as in Example 1 was performed except that 1000 mg of the supported catalyst slurry prepared in Comparative Preparation Example 1 was used instead of the supported catalyst slurry prepared in Comparative Preparation Example 1. The results are shown in Table 1.

[Example 2]
A mixture of 1052 mg of the supported catalyst slurry prepared in Preparation Example 2 and 1.5 mL of triethylaluminum decane solution (Al = 0.5 M) was charged into a 3.4 L internal volume SUS autoclave sufficiently purged with nitrogen. . Next, 600 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

[Example 3]
A mixture of 1309 mg of the slurry of the supported catalyst prepared in Preparation Example 3 and 1.5 mL of a decane solution of triethylaluminum (Al = 0.5 M) was charged into a 3.4 L internal volume SUS autoclave sufficiently purged with nitrogen. . Next, 600 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

[Example 4]
A mixture of 1571 mg of the slurry of the supported catalyst prepared in Preparation Example 4 and 1.5 mL of a decane solution of triethylaluminum (Al = 0.5M) was charged into a 3.4 L internal volume SUS autoclave sufficiently purged with nitrogen. . Next, 600 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

[Example 5]
A mixture of 727.8 mg of the supported catalyst slurry prepared in Preparation Example 5 and 1.5 mL of a triethylaluminum decane solution (Al = 0.5 M) was placed in a 3.4 L internal volume SUS autoclave sufficiently purged with nitrogen. I entered. Next, 600 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

[Example 6]
A mixture of 1913 mg of the supported catalyst slurry prepared in Preparation Example 6 and 1.5 mL of triethylaluminum decane solution (Al = 0.5 M) was charged into a 3.4 L internal volume SUS autoclave sufficiently purged with nitrogen. . Next, 600 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

[Example 7]
A mixture of 165 mg of the supported catalyst slurry prepared in Preparation Example 7 and 1.5 mL of a triisobutylaluminum hexane solution (Al = 0.5 M) was charged into a 3.4 L SUS autoclave sufficiently purged with nitrogen. did. Next, 600 g of liquid propylene was charged, and polymerization was performed at 70 ° C. for 40 minutes with sufficient stirring. The obtained polymer was dried under reduced pressure at 80 ° C. for 10 hours. The results are shown in Table 1.

  Example 1 using the catalyst A as the transition metal compound (A) and the support (B) (solid polyaluminoxane composition (B) having an aluminum content of 36% or more) as the support was used as the transition metal compound (A). It can be seen that [η] of the obtained polymer is larger than that of Comparative Example 1 using the same catalyst A but using a silica carrier as a carrier. Comparison between Example 1 and Comparative Example 1 and high molecular weight based on use of carrier (B) (solid polyaluminoxane composition (B)) described in “Mode for Carrying Out the Invention” According to the presumed mechanism of manifestation of the effect of Examples 2 to 7 in which catalyst B, catalyst C, catalyst D or catalyst E was used as the transition metal compound (A), the support was changed from the support (B) to a silica support or the like. When changed, it is presumed that [η] of the obtained polymer becomes small.

Claims (8)

A method for producing a propylene polymer having a polymerization step of polymerizing propylene in the presence of a propylene polymerization catalyst containing a transition metal compound (A) and a carrier (B),
The transition metal compound (A) is represented by the following general formula [Ia],

[In the formula [Ia], R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ are each independently a hydrogen atom, a hydrocarbon group, a heteroatom-containing hydrocarbon group or a silicon-containing group, and any two substituents of R ¹ to R ¹⁶ are bonded to each other. May form a ring,
M is a Group 4 transition metal,
Q is a halogen atom, a hydrocarbon group, an anionic ligand or a neutral ligand capable of coordination with a lone pair, j is an integer of 1 to 4, and j is an integer of 2 or more, Q may be selected in the same or different combinations. ],
The carrier (B) comprises a solid polyaluminoxane composition containing a structural unit represented by the following formula [II] and having an aluminum content of 36% by mass or more,

The transition metal compound (A) is a method for producing a propylene polymer in which the carrier (B) is supported. In the general formula [Ia], R ¹ , R ³ , R ⁹ , R ¹² , R ¹³ and R ¹⁶ are hydrogen atoms, R ² is a hydrocarbon group having 1 to 20 carbon atoms, and M is zirconium. The method for producing a propylene-based polymer according to claim 1. The method for producing a propylene-based polymer according to claim 1 or 2, wherein the following general formula (Ia) satisfies the following (1) and (2).
(1) R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms.
(2) R ¹⁰ , R ¹¹ , R ¹⁴ and R ¹⁵ are each independently a hydrocarbon group or a hydrogen atom, or R ¹⁰ and R ¹¹ are bonded to each other to form a ring, and R ¹⁴ and R ¹⁵ Are bonded to each other to form a ring. A method for producing a propylene polymer having a polymerization step of polymerizing propylene in the presence of a propylene polymerization catalyst containing a transition metal compound (A) and a carrier (B),
The transition metal compound (A) is represented by the following general formula [Ib],

[In the formula [Ib], R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ , R ²⁶ , R ³¹ , R ³² , R ³³ , R ³⁴ , R ³⁵ and R ³⁶ are each independently a hydrogen atom, Two adjacent groups selected from hydrocarbon group, halogen-containing group, oxygen-containing group, nitrogen-containing group, boron-containing group, sulfur-containing group, phosphorus-containing group, silicon-containing group, germanium-containing group and tin-containing group They may combine with each other to form a ring,
M is a Group 4 transition metal atom,
X is each independently an atom or group selected from a hydrogen atom, a halogen atom, a hydrocarbon group, a halogen-containing hydrocarbon group, a silicon-containing group, an oxygen-containing group, a sulfur-containing group, a nitrogen-containing group, and a phosphorus-containing group;
Y is a divalent group, and is a group selected from a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing group, a silicon-containing group, a germanium-containing group, and a tin-containing group. ]
The carrier (B) comprises a solid polyaluminoxane composition containing a structural unit represented by the following formula [II] and having an aluminum content of 36% by mass or more,

The transition metal compound (A) is a method for producing a propylene polymer in which the carrier (B) is supported.   The method for producing a propylene-based polymer according to any one of claims 1 to 4, wherein the polymerization method in the polymerization step is bulk polymerization using propylene as a solvent.   The production of the propylene-based polymer according to any one of claims 1 to 5, wherein the solid polyaluminoxane composition is in the form of particles and the volume-based median diameter (D50) is in the range of 0.1 to 100 µm. Method. The method for producing a propylene-based polymer according to any one of claims 1 to 6, wherein the solid polyaluminoxane composition satisfies the following requirements (i) and (ii).
Requirement (i): The solubility in n-hexane at 25 ° C. measured by the following method (i) is less than 2.0 mol%.
Requirement (ii): The solubility in toluene at 25 ° C. measured by the following method (ii) is less than 2.0 mol%.
[Method (i)]
2 g of the solid polyaluminoxane composition is added to 50 mL of n-hexane maintained at 25 ° C., followed by stirring for 2 hours, followed by separation into a filtrate and a residue by filtration, and the aluminum in the filtrate. The concentration is measured using ICP emission spectroscopy (ICP-AES), and the solubility is determined as the ratio of aluminum atoms present in the filtrate to the amount of aluminum atoms corresponding to 2 g of the solid polyaluminoxane composition.
[Method (ii)]
Solubility is calculated | required by the method similar to the said method (i) except using toluene instead of n-hexane. The propylene-based polymer according to any one of claims 1 to 7, wherein the solid polyaluminoxane composition is particulate, and a uniformity index represented by the following formula of the composition is 0.45 or less. Manufacturing method.
Uniformity index = ΣXi | D50−Di | / D50ΣXi
[Wherein, Xi represents a histogram value of particle i in particle size distribution measurement, D50 represents a volume-based median diameter, and Di represents a volume-based diameter of particle i. ]