JP6106442B2 - Propylene polymer production method - Google Patents

Description

  The present invention relates to a method for producing a propylene polymer, and more particularly to a method for producing a propylene polymer with controlled stereoregularity.

  In general, it is known that the properties of propylene polymers are greatly affected by their stereoregularity. In particular, the desired properties may not be obtained if the mesopentad fraction (mmmm) value of the propylene polymer is different by 1%. For this reason, various studies have been made on methods for controlling the stereoregularity of propylene polymers.

For example, the stereoregularity of the propylene polymer is greatly influenced by the complex structure of the polymerization catalyst. Among the polymerization catalysts, the metallocene catalyst has high catalytic activity during polymerization, and it is possible to design a resin having a desired stereoregularity by controlling the polymerization reaction derived from the geometric structure of the complex.
Non-Patent Document 1 uses a synthesis of stereoblock polypropylene using a C1-symmetric bridged metallocene or a non-bridged 2-substituted phenylindene complex as a method for controlling the stereoregularity of the propylene polymer depending on the polymerization conditions. The synthesis of polypropylene having a block portion of isotactic polypropylene (IPP) -atactic polypropylene (APP) was disclosed. However, the method described in Non-Patent Document 1 has a practical problem because the resulting polymer contains many components having different stereoregularity.

On the other hand, in polymerization using a C2-symmetric bridged metallocene, a method of polymerizing propylene with controlled stereoregularity using a polyene compound has been studied (Patent Document 1).
On the other hand, a method of polymerizing propylene with controlled stereoregularity by changing the polymerization conditions has been studied. Patent Document 2 discloses a method of adjusting a polymerization reaction rate by changing a propylene partial pressure in a reaction field.

JP-A-8-3111119 JP 2011-236352 A

“Journal of the American Chemical Society”, 1999, Vol. 121, p. 4348-4355

  However, in the method described in Patent Document 1, since a polyene compound that is a constituent component other than the polymer polymerization component is added to the reaction system, an undesirable side reaction proceeds or an additive is mixed into the resin. As a result, the quality of the polymer is lowered, and the mechanical properties of the polymer may be lowered. Further, in the method described in Patent Document 2, since the propylene concentration in the reaction solution changes by changing the propylene partial pressure in the reactor, it is necessary to separately control the molecular weight of the obtained polymer.

  An object of the present invention is to produce a propylene polymer whose stereoregularity is more precisely controlled without changing the molecular weight of the polymer.

That is, the present invention provides the following method for producing a propylene polymer.
<1> A method for producing a propylene polymer with controlled stereoregularity,
Step (1): A polymerization step in which hydrogen and propylene are supplied into the reactor and propylene is polymerized in the presence of a transition metal complex and organoaluminum to produce a propylene polymer.
Step (2): Step of measuring the stereoregularity (mmmm%) of the propylene polymer obtained in Step (1), and Step (3): Stereoregularity of the propylene polymer measured in Step (2) When the measured value is higher than the target value, at least one of the following operations (a1) to (a4) is performed, and when the measured value is lower than the target value: The manufacturing method of a propylene polymer including the control process which performs at least 1 operation of following (b1)-(b4).
(A1) Increasing the concentration of organoaluminum in the reactor (a2) Decreasing the partial pressure of hydrogen supplied to the polymerization step (a3) Increasing the amount of impurities contained in propylene supplied to the polymerization step (a4 (B1) Increase the polymerization temperature (b1) Decrease the concentration of organoaluminum in the reactor (b2) Increase the partial pressure of hydrogen supplied to the polymerization step (b3) Amount of impurities contained in propylene supplied to the polymerization step (B4) Lowering the polymerization temperature <2> The propylene polymer according to <1>, wherein the organoaluminum is at least one selected from the group consisting of trialkylaluminum, dialkylaluminum halide and organic alumoxane. Production method.
<3> The method for producing a propylene polymer according to <1> or <2>, wherein the transition metal complex is a chelate complex or a metallocene complex.
<4> The method for producing a propylene polymer according to any one of <1> to <3>, wherein the transition metal complex is a bibridged metallocene complex represented by the following general formula (I).
[In the formula, M represents a metal element of Groups 3 to 10 of the periodic table, and E ¹ and E ² represent a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a heterocyclopentadienyl group, a substituted heterocycle, respectively. A ligand selected from a cyclopentadienyl group, an amide group, a phosphide group, a hydrocarbon group and a silicon-containing group, which forms a cross-linked structure via A ¹ and A ² , and May be the same or different from each other, X represents a σ-bonding ligand, and when there are a plurality of X, the plurality of Xs may be the same or different, and other X, E ¹ , E ² or It may be cross-linked with Y. Y represents a Lewis base, and when there are a plurality of Y, the plurality of Y may be the same or different, may be cross-linked with other Y, E ¹ , E ² or X, and A ¹ and A ² are A divalent bridging group that binds two ligands, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, a tin-containing group , -O -, - CO -, - S -, - SO 2 -, - Se -, - NR 1 -, - PR 1 -, - P (O) R 1 -, - BR 1 - or -AlR ¹ - R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other. q represents an integer of 1 to 5 and represents [(M valence) -2], and r represents an integer of 0 to 3. ]

  According to the present invention, it is possible to produce a propylene polymer whose stereoregularity is more precisely controlled without changing the molecular weight of the polymer.

It is a flowchart which shows the propylene polymerization process of this invention.

[Propylene Polymer Production Method]
The method of the present invention is a method for producing a propylene polymer whose stereoregularity is precisely controlled. As described above, the properties of the propylene polymer are greatly influenced by the stereoregularity, and the desired properties may not be obtained only by slightly different values of the stereoregularity (mesopentad fraction) of the propylene polymer. is there.
In contrast, in the present invention, the stereoregularity of the propylene polymer obtained by polymerization is measured, the measured value is compared with a preset target value, and the difference is fed back to the polymerization process. Polymerization is performed by changing the stereoregularity and catalytic activity of the catalyst by a predetermined means. By performing this series of operations until the measured value matches the target value, the stereoregularity of the propylene polymer can be precisely controlled, and a propylene polymer having the target stereoregularity is produced. Can do.
Hereinafter, each step in the method of the present invention will be described in detail.

<Step (1)>
Step (1) in the method of the present invention is a polymerization step in which hydrogen and propylene are supplied into the reactor, and propylene is polymerized in the presence of a transition metal complex and organoaluminum to produce a propylene polymer.
Propylene is a raw material monomer, and hydrogen is used to adjust the molecular weight of the resulting propylene polymer.

(Transition metal complex)
Examples of transition metal complexes include chelate-type complexes and metallocene complexes.
Examples of the chelate-type complex include N, N′-bis (2,6-diisopropylphenyl) -1,2-dimethylethylenediiminonickel dibromide, N, N′-bis (2,6-diisopropylphenyl)- 1,2-dimethylethylenediiminopalladium dibromide and the like.

  Examples of the metallocene complex include a metallocene complex having a non-bridged ligand and a metallocene complex having a bridged ligand. A metallocene complex in which a ligand forms a crosslinked structure via a crosslinking group has a higher polymerization activity than a metallocene complex in which a crosslinked structure is not formed. Accordingly, among metallocene complexes, metallocene complexes in which a ligand forms a crosslinked structure via a crosslinking group are preferred, mono-bridged metallocene complexes and bi-bridged metallocene complexes are more preferred, and bi-bridged metallocene complexes are most preferred.

  Examples of the metallocene complex having a non-bridged ligand include biscyclopentadienylzirconium dichloride, bis (n-butylcyclopentadienyl) zirconium dichloride, bis (pentamethylcyclopentadienyl) zirconium dichloride, and bisindene. Nilzirconium dichloride and the like.

  Examples of mono-bridged metallocene complexes include dimethylsilylene (tetramethylcyclopentadienyl) (3-tert-butyl-5-methyl-2-phenoxy) zirconium dichloride, dimethylsilylene (tetramethylcyclopentadienyl) (tert-butylamide) Zirconium dichloride, dimethylsilylenebis (2-methyl-4,5-benzoindenyl) zirconium dichloride, dimethylsilylenebis (2-methyl-4-phenylindenyl) zirconium dichloride, dimethylsilylenebis (2-methyl-4-naphthyl) Indenyl) zirconium dichloride, dimethylsilylene bis (2-methylindenyl) zirconium dichloride, ethylenebis (2-methylindenyl) zirconium dichloride, and the like.

  Examples of the bibridged metallocene complex include bibridged metallocene complexes represented by the following general formula (I).

[In the formula, M represents a metal element of Groups 3 to 10 of the periodic table, and E ¹ and E ² represent a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a heterocyclopentadienyl group, a substituted heterocycle, respectively. A ligand selected from a cyclopentadienyl group, an amide group, a phosphide group, a hydrocarbon group and a silicon-containing group, which forms a cross-linked structure via A ¹ and A ² , and May be the same or different from each other, X represents a σ-bonding ligand, and when there are a plurality of X, the plurality of Xs may be the same or different, and other X, E ¹ , E ² or It may be cross-linked with Y. Y represents a Lewis base, and when there are a plurality of Y, the plurality of Y may be the same or different, may be cross-linked with other Y, E ¹ , E ² or X, and A ¹ and A ² are A divalent bridging group that binds two ligands, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, a tin-containing group , -O -, - CO -, - S -, - SO 2 -, - Se -, - NR 1 -, - PR 1 -, - P (O) R 1 -, - BR 1 - or -AlR ¹ - R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other. q represents an integer of 1 to 5 and represents [(M valence) -2], and r represents an integer of 0 to 3. ]

  In general formula (I), M represents a metal element belonging to Groups 3 to 10 of the periodic table, and specific examples include titanium, zirconium, hafnium, yttrium, vanadium, chromium, manganese, nickel, cobalt, palladium, and lanthanoid metals. Etc. Among these, a metal element belonging to Group 4 of the periodic table is preferable from the viewpoint of olefin polymerization activity and the like, and titanium, zirconium and hafnium are preferable.

E ¹ and E ² are respectively substituted cyclopentadienyl group, indenyl group, substituted indenyl group, heterocyclopentadienyl group, substituted heterocyclopentadienyl group, amide group (—N <), phosphine group (—P <), Hydrocarbon group [>CR-,> C <] and silicon-containing group [>SiR-,> Si <] (where R is hydrogen, a hydrocarbon group having 1 to 20 carbon atoms, or a heteroatom-containing group. A ligand selected from among (A), and a crosslinked structure is formed via A ¹ and A ² .
As E ¹ and E ² , a substituted cyclopentadienyl group, an indenyl group, and a substituted indenyl group are preferable because the polymerization activity becomes higher. E ¹ and E ² may be the same as or different from each other. From the viewpoint of proceeding polymerization on one kind of active site and obtaining a propylene polymer having a certain disorder according to the geometric structure of the complex, it is preferable to use a C2 symmetric metallocene complex, and E ¹ and E ² Are preferably identical to each other.

  X represents a σ-bonding ligand, and specific examples thereof include a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, Examples thereof include an amide group having 1 to 20 carbon atoms, a silicon-containing group having 1 to 20 carbon atoms, a phosphide group having 1 to 20 carbon atoms, a sulfide group having 1 to 20 carbon atoms, and an acyl group having 1 to 20 carbon atoms. q is an integer of 1 to 5 and represents [(valence of M) -2]. When q is 2 or more, a plurality of X may be the same or different.

Examples of the halogen atom include a chlorine atom, a fluorine atom, a bromine atom, and an iodine atom.
Examples of the hydrocarbon group having 1 to 20 carbon atoms include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, a cyclohexyl group, and an octyl group; an alkenyl group such as a vinyl group, a propenyl group, and a cyclohexenyl group An arylalkyl group such as benzyl group, phenylethyl group, phenylpropyl group; phenyl group, tolyl group, dimethylphenyl group, trimethylphenyl group, ethylphenyl group, propylphenyl group, biphenyl group, naphthyl group, methylnaphthyl group, anthracenyl group Group, aryl group such as phenanthonyl group, and the like.
Examples of the alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, propoxy group, butoxy group, phenylmethoxy group, and phenylethoxy group. Examples of the aryloxy group having 6 to 20 carbon atoms include a phenoxy group, a methylphenoxy group, and a dimethylphenoxy group.

Examples of the amide group having 1 to 20 carbon atoms include a dimethylamide group, a diethylamide group, a dipropylamide group, a dibutylamide group, a dicyclohexylamide group, and a methylethylamide group; a divinylamide group, a dipropenylamide group, Examples include alkenylamide groups such as dicyclohexenylamide groups; arylalkylamide groups such as dibenzylamide groups, phenylethylamide groups, and phenylpropylamide groups; arylamide groups such as diphenylamide groups and dinaphthylamide groups.
Examples of the silicon-containing group having 1 to 20 carbon atoms include monohydrocarbon-substituted silyl groups such as methylsilyl group and phenylsilyl group; dihydrocarbon-substituted silyl groups such as dimethylsilyl group and diphenylsilyl group; trimethylsilyl group, triethylsilyl group, Trihydrocarbon-substituted silyl such as tripropylsilyl group, dimethyl (t-butyl) silyl group, tricyclohexylsilyl group, triphenylsilyl group, dimethylphenylsilyl group, methyldiphenylsilyl group, tolylsilylsilyl group, trinaphthylsilyl group, etc. A hydrocarbon-substituted silyl ether group such as a trimethylsilyl ether group; a silicon-substituted alkyl group such as a trimethylsilylmethyl group; a silicon-substituted aryl group such as a trimethylsilylphenyl group; a dimethylhydrosilyl group and a methyldihydrosilyl group;

Specific examples of the phosphide group having 1 to 20 carbon atoms include dimethyl phosphide group, methylphenyl phosphide group, diphenyl phosphide group, dicyclohexyl phosphide group, and dibenzyl phosphide group.
Examples of the sulfide group having 1 to 20 carbon atoms include alkyl sulfide groups such as methyl sulfide group, ethyl sulfide group, propyl sulfide group, butyl sulfide group, hexyl sulfide group, cyclohexyl sulfide group, octyl sulfide group; vinyl sulfide group, propenyl sulfide Group, alkenyl sulfide group such as cyclohexenyl sulfide group; arylalkyl sulfide group such as benzyl sulfide group, phenylethyl sulfide group, phenylpropyl sulfide group; phenyl sulfide group, tolyl sulfide group, dimethylphenyl sulfide group, trimethylphenyl sulfide group, Ethyl phenyl sulfide group, propyl phenyl sulfide group, biphenyl sulfide group, naphthyl sulfide group, methyl naphthyl sulfide group, Tiger Se Nils sulfide groups, and aryl sulfide groups such as a phenanthridine Nils sulfide group.
Examples of the acyl group having 1 to 20 carbon atoms include formyl group, acetyl group, propionyl group, butyryl group, valeryl group, palmitoyl group, stearoyl group, oleoyl group and other alkyl acyl groups, benzoyl group, toluoyl group, salicyloyl group, Examples thereof include arylacyl groups such as cinnamoyl group, naphthoyl group and phthaloyl group, and oxalyl group, malonyl group and succinyl group respectively derived from dicarboxylic acid such as oxalic acid, malonic acid and succinic acid.

Y represents a Lewis base, and specific examples thereof include amines, ethers, phosphines, thioethers, and the like. r represents an integer of 0 to 3, and when r is 2 or 3, a plurality of Y may be the same or different.
Examples of amines include amines having 1 to 20 carbon atoms, specifically, methylamine, ethylamine, propylamine, butylamine, cyclohexylamine, methylethylamine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dicyclohexyl. Alkylamines such as amine, methylethylamine, trimethylamine, triethylamine, tri-n-butylamine; alkenylamines such as vinylamine, propenylamine, cyclohexenylamine, divinylamine, dipropenylamine, dicyclohexenylamine; phenylmethylamine, phenylethylamine Arylalkylamines such as phenylpropylamine; arylamines such as diphenylamine and dinaphthylamine; or ammonia, aniline, N Methylaniline, diphenylamine, N, N-dimethylaniline, methyldiphenylamine, pyridine and p- bromo -N, N-dimethylaniline.

  Specific examples of ethers include aliphatic single ether compounds such as methyl ether, ethyl ether, propyl ether, isopropyl ether, butyl ether, isobutyl ether, n-amyl ether, isoamyl ether; methyl ethyl ether, methyl propyl ether, methyl isopropyl Aliphatic hybrid ether compounds such as ether, methyl-n-amyl ether, methyl isoamyl ether, ethyl propyl ether, ethyl isopropyl ether, ethyl butyl ether, ethyl isobutyl ether, ethyl n-amyl ether, ethyl isoamyl ether; vinyl ether, allyl ether Aliphatic unsaturated ether compounds such as methyl vinyl ether, methyl allyl ether, ethyl vinyl ether, and ethyl allyl ether; Aromatic ether compounds such as ethylene oxide, propylene oxide, trimethylene oxide, tetrahydrofuran, tetrahydropyran, dioxane and the like; aromatic ether compounds such as alcohol, phenetol, phenyl ether, benzyl ether, phenyl benzyl ether, α-naphthyl ether, β-naphthyl ether; An ether compound etc. are mentioned.

Examples of phosphine include phosphine having 1 to 20 carbon atoms. Specific examples include monohydrocarbon-substituted phosphines such as methylphosphine, ethylphosphine, propylphosphine, butylphosphine, hexylphosphine, cyclohexylphosphine, and octylphosphine; dimethylphosphine, diethylphosphine, dipropylphosphine, dibutylphosphine, dihexylphosphine, dicyclohexyl Dihydrocarbon-substituted phosphines such as phosphine and dioctylphosphine; Trimethylphosphine, triethylphosphine, tripropylphosphine, tributylphosphine, trihexylphosphine, tricyclohexylphosphine, and trihydrocarbon-substituted phosphine alkylphosphine; , Monoalkenes such as propenylphosphine and cyclohexenylphosphine Phosphine and dialkenylphosphine in which two alkenyl hydrogen atoms are substituted; trialkenylphosphine in which three alkenyl hydrogen atoms are substituted; arylalkylphosphine such as benzylphosphine, phenylethylphosphine, and phenylpropylphosphine; Diarylalkylphosphine or aryldialkylphosphine substituted with 3 aryl or alkenyl hydrogen atoms; phenylphosphine, tolylphosphine, dimethylphenylphosphine, trimethylphenylphosphine, ethylphenylphosphine, propylphenylphosphine, biphenylphosphine, naphthylphosphine, methylnaphthylphosphine , Anthracenylphosphine, phenanthenylphosphine; phosphine hydrogen Child alkylaryl Two substituted di (alkylaryl) phosphine; arylphosphine such as a hydrogen atom of phosphine alkylaryl three substituted with tri (alkylaryl) phosphines, and the like.
Specific examples of the thioether include the above sulfides.
Y represents a Lewis base, and when there are a plurality of Y, the plurality of Y may be the same or different, and may be cross-linked with other Y, E ¹ , E ² or X. Specific examples of the Lewis base of Y include amines, ethers, phosphines, thioethers and the like.

A ¹ and A ² are divalent bridging groups that bind two ligands, and each has a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, Germanium-containing group, tin-containing group, —O—, —CO—, —S—, —SO ₂ —, —Se—, —NR ¹ —, —PR ¹ —, —P (O) R ¹ —, —BR ¹ -or -AlR ^1- , wherein R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which are the same or different from each other. May be.

As a C1-C20 hydrocarbon group, the thing similar to what was mentioned above as a specific example of X is mentioned. Specific examples of the halogen-containing hydrocarbon group include chloromethyl group, bromomethyl group, bromoethyl group, p-fluorophenyl group, p-fluorophenylmethyl group, 3,5-difluorophenyl group, pentachlorophenyl group, 3,4, A 5-trifluorophenyl group, a pentafluorophenyl group, a 3,5-bis (trifluoromethyl) phenyl group, and the like can be given.
Specific examples of silicon-containing groups include monohydrocarbon-substituted silyl groups such as methylsilyl and phenylsilyl groups; dihydrocarbon-substituted silyl groups such as dimethylsilyl and diphenylsilyl groups; trimethylsilyl, triethylsilyl, and tripropylsilyl Groups, trihydrocarbon-substituted silyl groups such as dimethyl (t-butyl) silyl group, tricyclohexylsilyl group, triphenylsilyl group, dimethylphenylsilyl group, methyldiphenylsilyl group, tolylsilylsilyl group, trinaphthylsilyl group; Examples include hydrocarbon-substituted silyl ether groups such as ether groups; silicon-substituted alkyl groups such as trimethylsilylmethyl groups; silicon-substituted aryl groups such as trimethylsilylphenyl groups, dimethylhydrosilyl groups, and methyldihydrosilyl groups.

As the crosslinking group represented by A ¹ and A ² , a group represented by the following general formula is preferable.
(D is carbon, silicon or tin, R ² and R ³ are each a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other, and are bonded to each other to form a ring structure. (E may represent an integer of 1 to 4)

Specific examples thereof include a methylene group, an ethylene group, an ethylidene group, a propylidene group, an isopropylidene group, a cyclohexylidene group, a 1,2-cyclohexylene group, a vinylidene group (CH ₂ = C =), a dimethylsilylene group, and diphenyl. Examples thereof include a silylene group, a methylphenylsilylene group, a dimethylgermylene group, a dimethylstannylene group, a tetramethyldisilylene group, and a diphenyldisilylene group. Among these, an ethylene group, an isopropylidene group, and a dimethylsilylene group are preferable because the polymerization activity becomes higher.

  In such a bibridged metallocene complex represented by the general formula (I), a compound represented by the following general formula (II) or (III) is preferable from the viewpoint of higher polymerization activity.

In formula (II) and (III), M, A ^1, A ^2, q and r, M in Formula (I), is the same as A ^1, A ^2, q and r.
X ¹ represents a σ-bonding ligand, and when plural X ^1, a plurality of X ¹ may be the same or different, may be crosslinked with other X ¹ or Y ^1. Specific examples of X ¹ include the same examples as those exemplified in the description of X in formula (I).
Y ¹ represents a Lewis base, if Y ¹ is plural, Y ¹ may be the same or different, may be crosslinked with other Y ¹ or X ^1. Specific examples of Y ¹ are the same as those exemplified in the description of Y in the general formula (I).

R ^{4 to} R ¹³ each represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, or a heteroatom-containing group. Examples of the halogen atom, the hydrocarbon group having 1 to 20 carbon atoms, and the silicon-containing group are the same as those described in the general formula (I). Examples of the halogen-containing hydrocarbon group having 1 to 20 carbon atoms include p-fluorophenyl group, 3,5-difluorophenyl group, 3,4,5-trifluorophenyl group, pentafluorophenyl group, 3,5-bis ( (Trifluoro) phenyl group, fluorobutyl group and the like. Examples of the heteroatom-containing group include C1-C20 heteroatom-containing groups. Specifically, nitrogen-containing groups such as a dimethylamino group, a diethylamino group, and a diphenylamino group; a phenylsulfide group, a methylsulfide group, and the like Sulfur-containing groups of: phosphorus-containing groups such as dimethylphosphino groups and diphenylphosphino groups; oxygen-containing groups such as methoxy groups, ethoxy groups, and phenoxy groups. Among these, as R ⁴ and R ⁵ , a group containing a hetero atom such as a halogen atom, oxygen, or silicon, or a hydrocarbon group having 1 to 20 carbon atoms is preferable because of high polymerization activity. Also, from the viewpoint of synthesizing a polymer having a balance between the bonding ratio and the melting endotherm by controlling the monomer coordination space, trimethylsilylmethyl groups are particularly preferred as R ⁴ and R ⁵ . R ^{6 to} R ¹³ are preferably a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms.
The metallocene complex having the bibridged biscyclopentadienyl derivative as a ligand preferably contains silicon in the bridging group between the ligands.

Specific examples of the bibridged metallocene complex represented by the general formula (I) include International Publication No. 95/009172, Japanese Unexamined Patent Publication No. 2000-256411, International Publication No. 02/024714, and Japanese Unexamined Patent Publication No. 2002-308893. Specific examples described in the gazette and the like can also be suitably used in the present invention.
Among these, (1,2′-dimethylsilylene) (2,1′-dimethylsilylene) -bisindenylzirconium dichloride, (1,2′-dimethylsilylene) (2,1′-dimethylsilylene)-(3 -Trimethylsilylmethylindenyl) (indenyl) zirconium dichloride, (1,2'-dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride are preferred, (1,2 ' -Dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride is particularly preferred.

  The synthesis method of the bibridged metallocene complex represented by the general formula (I) is, for example, “J. Organomet. Chem., Vol. 369, p. 359 (1989)”. It can be synthesized by the method described in 1. That is, it can be synthesized by a reaction between a corresponding substituted cycloalkenyl anion and a metal halide represented by M in the general formula (I).

(Organic aluminum)
Organoaluminum is a component used as a so-called scavenger for the purpose of removing water in the polymerization reaction system and a component for the purpose of generating and stabilizing the active site (cation complex) of the catalyst, and forms a dormant with the transition metal complex. A compound. The organoaluminum is preferably at least one selected from the group consisting of trialkylaluminum, dialkylaluminum halide and organic alumoxane. One kind of organic aluminum may be used, or two or more kinds may be used in combination.

Examples of the organic aluminum include compounds represented by the following general formula (IV).
R ²⁰ _v AlJ _3-v (IV)
[Wherein, R ²⁰ represents an alkyl group having 1 to 10 carbon atoms, J represents a hydrogen atom, an alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, or a halogen atom, and v represents 1 to 3 carbon atoms. (It is an integer)
Specific examples of the compound represented by the general formula (IV) include trialkylaluminum such as trimethylaluminum, triethylaluminum, triisopropylaluminum and triisobutylaluminum; dialkyl such as dimethylaluminum chloride, diethylaluminum chloride and dimethylaluminum fluoride. Examples include aluminum halides; alkylaluminum dihalides such as methylaluminum dichloride and ethylaluminum dichloride; dialkylaluminum hydrides such as diethylaluminum hydride and diisobutylaluminum hydride; and alkylaluminum sesquihalides such as ethylaluminum sesquichloride. Among these, an organoaluminum compound to which a hydrocarbon group having 4 or more carbon atoms, preferably 4 to 8 carbon atoms, more preferably 6 to 8 carbon atoms is bonded is preferable in terms of excellent high-temperature stability.

  Moreover, as organoaluminum, the chain | strand-shaped aluminoxane represented by the following general formula (V) or the cyclic | annular aluminoxane represented by general formula (VI) can also be mentioned.

(In the formula, R ²¹ represents a hydrocarbon group such as an alkyl group, alkenyl group, aryl group, arylalkyl group or the like having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, or a halogen atom, and w represents an average degree of polymerization. In general, it is an integer of 2 to 50, preferably 2 to 40. Note that each R ²¹ may be the same or different.

Examples of the aluminoxane represented by the general formula (V) or (VI) include linear or cyclic tetramethyldialumoxane, tetraisobutyldialumoxane, methylalumoxane, ethylalumoxane, butylalumoxane, isobutylalumoxane. Etc.
Examples of the method for producing aluminoxane include a method in which an alkylaluminum is brought into contact with a condensing agent such as water, but the means thereof is not particularly limited and may be reacted according to a known method.
For example, (1) a method in which an organoaluminum compound is dissolved in an organic solvent and brought into contact with water, (2) a method in which an organoaluminum compound is initially added during polymerization, and water is added later, (3) a metal There are a method of reacting crystallization water contained in a salt or the like, water adsorbed on an inorganic or organic material with an organoaluminum compound, and (4) a method of reacting a tetraalkyldialuminoxane with a trialkylaluminum and further reacting with water. . The aluminoxane may be insoluble in toluene. These aluminoxanes may be used alone or in combination of two or more.

The use ratio of the transition metal complex and the organoaluminum in the polymerization catalyst used in the production method of the present invention is a molar ratio, preferably 1: 1 to 1: 10000, more preferably 1: 5 to 1: 2000, still more preferably. Is in the range of 1:10 to 1: 1000. If it exists in this range, the balance of the addition effect of organic aluminum and economical efficiency will be favorable, and there is no possibility that aluminum may exist in a large amount in the obtained propylene polymer.
The organoaluminum may be supplied to the reaction system separately from the transition metal complex. Moreover, you may supply to the catalyst for prepolymerization.

  The polymerization catalyst used in the production method of the present invention is produced according to the description of International Publication No. 95/009172, Japanese Patent Application Laid-Open No. 2000-256411, International Publication No. 02/024714, Japanese Patent Application Laid-Open No. 2002-308893, and the like. can do.

(Polymerization method and polymerization conditions)
In the present invention, the polymerization method is not particularly limited, and any method such as a slurry polymerization method, a gas phase polymerization method, a bulk polymerization method, a solution polymerization method, and a suspension polymerization method may be used. A polymerization method is particularly preferred. About polymerization conditions, superposition | polymerization temperature is 0-200 degreeC normally, More preferably, it is 20-200 degreeC, Most preferably, it is 70-200 degreeC. The ratio of the catalyst to the reaction raw material is preferably raw material propylene / the transition metal complex (molar ratio) is preferably 1 to 100000000, more preferably 1 to 1000. The polymerization time is usually 5 minutes to 30 hours, preferably 15 minutes to 25 hours.
As a method for adding a catalyst component containing a transition metal complex, addition in a catalyst solution is preferable from the viewpoint of the degree of dispersion of the catalyst.

When using a polymerization solvent, for example, aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and decalin, alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane, aliphatics such as pentane, hexane, heptane and octane Hydrocarbons, halogenated hydrocarbons such as chloroform and dichloromethane can be used. These solvents may be used alone or in combination of two or more.
Moreover, it can carry out without a solvent depending on the polymerization method.

(Preliminary polymerization)
In the polymerization, a polymerization catalyst may be prepared by performing preliminary polymerization. The prepolymerization can be performed, for example, by bringing a small amount of olefin into contact with the catalyst component, but the method is not particularly limited, and a known method can be used. The prepolymerization temperature is usually -20 to 200 ° C, preferably -10 to 130 ° C, more preferably 0 to 80 ° C. In the prepolymerization, aliphatic hydrocarbons, aromatic hydrocarbons, monomers and the like can be used as solvents. The solvent is preferably an aromatic hydrocarbon from the viewpoint that the active species is easily dissolved. Moreover, you may perform prepolymerization without a solvent. In the prepolymerization, the intrinsic viscosity [η] (measured in decalin at 135 ° C.) of the prepolymerized product is 0.1 dL / g or more, and the amount of the prepolymerized product per 1 mmol of the transition metal component in the catalyst is 1 to It is preferable to adjust the conditions to be 10,000 g, particularly 10 to 1000 g.

<Step (2)>
Step (2) in the method of the present invention is a step of measuring the stereoregularity (mmmm%) of the propylene polymer obtained in step (1).
As described above, the properties of the propylene polymer are greatly influenced by the stereoregularity, and the desired properties may not be obtained only by slightly different values of the mesopentad fraction of the propylene polymer. Therefore, first, the stereoregularity of the propylene polymer is measured in this step, and the control is performed in the next step (3).

The mesopentad fraction (mmmm) is measured by the signal of the methyl group in the ¹³ C-NMR spectrum in accordance with the method proposed by A. Zambelli et al. In “Macromolecules, 6,925 (1973)”. It is a meso fraction in the pentad unit in the polypropylene molecular chain to be formed.
In the present invention, the ¹³ C nuclear magnetic resonance spectrum is measured according to the following apparatus and conditions in accordance with the assignment of peaks proposed by “Macromolecules, 8, 687 (1975)” by A. Zambelli et al. went.
Apparatus: JNM-EX400 type ¹³ C-NMR apparatus manufactured by JEOL Ltd. Method: Proton complete decoupling method Concentration: 220 mg / mL
Solvent: 1,2,4-trichlorobenzene / heavy benzene (volume ratio 90/10) Mixed solvent temperature: 130 ° C.
Pulse width: 45 °
Pulse repetition time: 4 seconds Integration: 10,000 times

<Step (3)>
In step (3) in the method of the present invention, the measured value of the stereoregularity of the propylene polymer measured in step (2) is compared with a preset target value, and the measured value is higher than the target value. Is a control step for performing at least one of the following operations (a1) to (a4) and performing at least one operation of the following (b1) to (b4) when the measured value is lower than the target value.
(A1) Increasing the concentration of organoaluminum in the reactor (a2) Decreasing the partial pressure of hydrogen supplied to the polymerization step (a3) Increasing the amount of impurities contained in propylene supplied to the polymerization step (a4 (B1) Increase the polymerization temperature (b1) Decrease the concentration of organoaluminum in the reactor (b2) Increase the partial pressure of hydrogen supplied to the polymerization step (b3) Amount of impurities contained in propylene supplied to the polymerization step (B4) lower the polymerization temperature

In this step, the measured value of the stereoregularity of the propylene polymer measured in the step (2) is compared with a preset target value, and the difference is fed back to the polymerization step of the step (1). The stereoregularity of the propylene polymer is precisely controlled by a predetermined means. In the present invention, as means for controlling the stereoregularity of the propylene polymer, the concentration of organoaluminum in the reactor, the partial pressure of hydrogen supplied to the polymerization step, and impurities contained in propylene supplied to the polymerization step ( Specifically, the amount of water, carbon monoxide, carbon dioxide, sulfur content, etc.) is varied. These means may be performed alone or in combination.
According to the method of the present invention, a propylene polymer whose stereoregularity is more precisely controlled can be produced without changing the molecular weight of the polymer. The molecular weight of the polymer can be indicated by the intrinsic viscosity, and if the fluctuation amount of the intrinsic viscosity is preferably 0.10 dL / g or less, more preferably 0.05 dL / g or less, the polymerization temperature can be finely adjusted. The molecular weight of the polymer can be adjusted by controlling the polymerization reaction.

(Concentration of organoaluminum in the reactor)
Organoaluminum is added in excess of the catalyst as a scavenger or for the activation of the complex, so it is present in large amounts near the active site. Therefore, it is estimated that not only the polymerization activity but also the molecular weight and stereoregularity of the resulting polymer are changed by the kind and concentration of organoaluminum affecting the coordination and growth process of the monomer.
For example, when triisobutylaluminum (TIBA) is used as organoaluminum, the metallocene complex is in an equilibrium state between an “active species” having an empty coordination position and an “inactive species (dormant)” to which TIBA is bound. It is thought that there is. In the polymer chain on the dormant, it is considered that “epimerization” occurs in which a hydrogen atom bonded to an asymmetric carbon atom at the β-position is once desorbed and re-added. Here, “epimerization” refers to the conversion of a compound into an epimer (a compound that has two or more chiral centers and is in a diastereomeric relationship, differing only in the configuration on one chiral center). It means converting. In the dormant, the growth reaction of the polymer chain does not proceed, so that the epimerization ratio increases as the organoaluminum concentration increases, and the stereoregularity is considered to decrease by returning to the active species by equilibrium.

Therefore, when the measured value of the stereoregularity of the propylene polymer is higher than the target value, the concentration of organoaluminum in the reactor is increased (a1). Thereby, the dormant concentration can be increased and the stereoregularity of the propylene polymer can be lowered. On the other hand, when the measured value is lower than the target value, the concentration of organoaluminum in the reactor is reduced (b1). Thereby, the dormant density | concentration can be reduced and the stereoregularity of a propylene polymer can be improved.
As a means for increasing or decreasing the concentration of organic aluminum, there is a method of controlling the amount of organic aluminum thrown into the supply line, or by adding and reacting a polar substance (water, alcohol, etc.) to organic aluminum. There is a method for controlling the concentration.

(Partial pressure of hydrogen supplied to the polymerization process)
The hydrogen partial pressure supplied to the polymerization step is preferably set to 1 kPa or more and 100 kPa or less. When the hydrogen partial pressure is high, the catalytic activity is improved, while when the hydrogen partial pressure is low, the catalytic activity is reduced.
Therefore, when the measured value of the stereoregularity of the propylene polymer is higher than the target value, the partial pressure of hydrogen supplied to the polymerization process is reduced (a2). Thereby, catalyst activity can be reduced and the stereoregularity of a propylene polymer can be reduced. On the other hand, when the measured value is lower than the target value, the partial pressure of hydrogen supplied to the polymerization process is increased (b2). Thereby, catalyst activity can be improved and the stereoregularity of a propylene polymer can be improved.
The reason why the regularity can be controlled by the partial pressure of hydrogen is that when the hydrogen concentration increases, the polymer chain undergoes chain transfer to hydrogen during the process of epimerization of the polymer chain, so the frequency of epimerization decreases. However, it is presumed that regularity increases.
The partial pressure of hydrogen supplied to the polymerization process can be adjusted by controlling the amount of hydrogen to be supplied to the supply line. When the hydrogen partial pressure is increased, the chain transfer to hydrogen is promoted, so that the molecular weight of the polymer decreases. Therefore, it is necessary to slightly adjust the molecular weight by changing the polymerization temperature.

  The present inventors have found that the stereoregularity of the propylene polymer can be controlled by controlling the rate of occurrence of epimerization depending on the polymerization conditions. The decrease in the stereoregularity of the polymer due to epimerization is considered to be related to the polymerization activity because it is a competitive reaction with the growth reaction of the polymer chain. For example, when the stereoregularity is reduced, the epimerization is increased or the growth reaction is decreased, which is considered to lead to a decrease in activity as a whole.

(Amount of impurities contained in propylene supplied to the polymerization process)
During the industrial production of propylene polymers, impurities such as water, carbon monoxide, carbon dioxide and sulfur, which are known as metallocene catalyst poisons, are purified before the raw material propylene is supplied to the reactor. It is common practice to remove propylene from the column. It is assumed that the component that becomes the catalyst poison is combined with the transition metal complex to form a dormant. Therefore, it is considered that epimerization occurs in the polymer chain on the dormant and the stereoregularity is lowered.
Therefore, when the measured value of the stereoregularity of the propylene polymer is higher than the target value, the amount of impurities contained in the propylene supplied to the polymerization process is increased (a3). Thereby, the dormant concentration can be increased and the stereoregularity of the propylene polymer can be lowered. On the other hand, when the measured value is lower than the target value, the amount of impurities contained in the propylene supplied to the polymerization step is reduced (b3). Thereby, the dormant density | concentration can be reduced and the stereoregularity of a propylene polymer can be improved.

The amount of impurities contained in the propylene supplied to the polymerization step may be controlled by removing what is present in the propylene supply source in the supply step, or may be newly supplied. As a means for reducing the amount of impurities in propylene, it is preferable to purify crude propylene using a column packed with a purification catalyst. Examples of the purification catalyst include activated alumina, molecular sieves, copper oxide, zinc oxide, palladium, nickel and the like, and activated alumina is preferable. In these purification catalysts, one or two or more kinds of catalysts are put into one adsorption tower, and the crude propylene containing impurities is purified by one or two or more continuous adsorption towers.
The impurities to be purified are preferably targeted for polar compounds such as carbon monoxide, carbon dioxide, and moisture in crude propylene, sulfur-containing compounds, oxygen-containing compounds, and compounds containing heteroatoms of nitrogen-containing compounds.

(Polymerization temperature)
As described above, the polymerization temperature is usually 0 to 200 ° C. When the polymerization temperature is high, the concentration of raw material propylene that can be dissolved in the reaction solution decreases, and the metallocene complex undergoes ligand vibration, which reduces the selectivity when propylene is inserted, and controls the stereoregularity of the polymer. May be reduced.
Therefore, when the measured value of the stereoregularity of the propylene polymer is higher than the target value, the polymerization temperature is raised (a4). Thereby, the raw material propylene density | concentration can reduce or the stereoregularity of a propylene polymer can be reduced by the ligand vibration of a metallocene complex. On the other hand, when the measured value is lower than the target value, the polymerization temperature is lowered (b4). Thereby, the stereoregularity of a propylene polymer can be improved.
The reason that the regularity can be controlled by the partial pressure of hydrogen is presumed that when the raw material propylene concentration is reduced, the occurrence frequency of polymer chain epimerization increases and the regularity decreases.
In addition, since the molecular weight of a polymer will change a lot when changing superposition | polymerization temperature, adjusting in the range of 0-10 degreeC is preferable. Further, from the viewpoint of changing only the stereoregularity without changing the molecular weight, the operations (a4) and (b4) are combined with any one of the operations (a1) to (a3) and (b1) to (b3). It is preferable.

  Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples.

[ ¹³ C-NMR measurement]
The ¹³ C-NMR spectrum was measured using the following apparatus and conditions to determine the mesopentad fraction [mmmm] of the propylene polymer.
Apparatus: JNM-EX400 type ¹³ C-NMR apparatus manufactured by JEOL Ltd. Method: Proton complete decoupling method Concentration: 220 mg / mL
Solvent: 1,2,4-trichlorobenzene / heavy benzene (volume ratio 90/10) mixed solvent Temperature: 130 ° C
Pulse width: 45 °
Pulse repetition time: 4 seconds Integration: 10,000 times

[Intrinsic viscosity (η)]
Viscometer (trade name: “VMR-053U-PC · F01”, manufactured by Kogyo Co., Ltd.), Ubbelohde viscometer (time volume: 2-3 mL, capillary diameter: 0.44-0.48 mm), Using tetralin as a solvent, a 0.02-0.16 g / dL solution was measured at 135 ° C. to determine the intrinsic viscosity of the propylene polymer.

[Catalytic activity]
The polymerization amount of the propylene polymer was calculated from the amount of polymerization heat determined from the heat balance of the polymerization vessel, and the production amount per unit catalyst amount determined by dividing this polymerization amount by the supply catalyst flow rate was defined as the catalyst activity.

Example 1-1
Polypropylene with a mesopentad fraction controlled to 47.5% (target value) was produced as follows.
<Step (1)>
A 200 L stainless steel reactor equipped with a stirrer was supplied with n-heptane at 25 L / h and triisobutylaluminum at 25 mmol / h, and dimethylanilinium tetrakispentafluorophenylborate and (1,2 ′ -Dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride, triisobutylaluminum and propylene in a molar ratio of 1: 7.5: 160. The catalyst component was continuously fed at 1 μmol / h in terms of zirconium.
The polymerization temperature was set to 65 ° C., triisobutylaluminum was supplied to the reactor at 25 mmol / h, the hydrogen concentration in the gas phase of the reactor was 9 mol%, and the total pressure in the reactor was 1.0 MPa (G) Thus, hydrogen and propylene passed through a purification column were continuously supplied to carry out the polymerization reaction for 120 minutes. As the purification column, “R3-12”, “R3-17” and “Selexsorb-COS” manufactured by BASF, and “MS-OG491” (trade name) manufactured by Union Showa Co., Ltd. were used.

<Step (2)>
The polypropylene obtained by removing n-heptane as a solvent was measured for mesopentad fraction [mmmm] and found to be 51.3 mol%. Moreover, it was 0.93 dL / g when intrinsic viscosity ((eta)) was measured.

<Step (3) -Operation (a3)>
Since the mesopentad fraction is higher than the target value of 47.5%, the flow ratio of propylene through the purification column and propylene through the bypass is 1: at the opening of the three-way valve installed at the inlet of the purification column. It adjusted so that it might become 1, and performed the polymerization reaction. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 50.4 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.91 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 1-2
<Step (3) -Operation (a3)>
Since the mesopentad fraction of the polypropylene obtained in Example 1-1 is still higher than the target value of 47.5%, only propylene that bypasses the purification column by switching the three-way valve is supplied to the reactor as raw material propylene. A polymerization reaction was performed. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 49.4 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.92 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 1-3
<Step (3) -Operation (a2)>
Since the mesopentad fraction of the polypropylene obtained in Example 1-2 is still higher than the target value of 47.5%, the polymerization temperature was set to 70 ° C., and the hydrogen concentration in the gas phase portion of the reactor was 1.8. Hydrogen and propylene which bypassed the purification column were continuously supplied to the reactor so as to maintain the mol% and the total pressure in the reactor at 1.0 MPa (G) to carry out the polymerization reaction. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 48.4 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.92 dL / g, and it was found that the intrinsic viscosity was not changed and the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 1-4
<Step (3) -Operation (a2)>
Since the mesopentad fraction of the polypropylene obtained in Example 1-3 is still higher than the target value of 47.5%, the polymerization temperature was set to 72 ° C., and the hydrogen concentration in the gas phase part of the reactor was 0.6. Hydrogen and propylene by-passing the purification column were continuously supplied so as to maintain the mol% and the total pressure in the reactor at 1.0 MPa · G, and the polymerization reaction was performed. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 47.8 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.92 dL / g, and it was found that the intrinsic viscosity was not changed and the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 2-1
In the following manner, polypropylene whose mesopentad fraction was controlled to 49.0% (target value) was produced.
<Step (1)>
A 200 L stainless steel reactor equipped with a stirrer was supplied with n-heptane at 25 L / h and triisobutylaluminum at 25 mmol / h, and dimethylanilinium tetrakispentafluorophenylborate and (1,2 ′ -Dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride, triisobutylaluminum and propylene in a molar ratio of 1: 7.5: 160. The catalyst component was continuously fed at 2 μmol / h in terms of zirconium.
The polymerization temperature was set to 67 ° C., triisobutylaluminum was fed to the reactor at 25 mmol / h, the hydrogen concentration in the gas phase of the reactor was 20 mol%, and the total pressure in the reactor was 1.0 MPa (G) Thus, hydrogen and propylene passed through a purification column were continuously supplied to carry out the polymerization reaction for 120 minutes. The same purification column as that used in Example 1-1 was used.

<Step (2)>
The polypropylene obtained by removing n-heptane as a solvent was measured for mesopentad fraction [mmmm] and found to be 50.6 mol%. Moreover, it was 0.63 dL / g when intrinsic viscosity ((eta)) was measured.

<Step (3) -Operation (a1)>
Since the mesopentad fraction was higher than the target value of 49.0%, the polymerization reaction was carried out by changing the amount of triisobutylaluminum supplied to the reactor to 50 mmol / h. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 49.8 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.63 dL / g, and there was no change in the intrinsic viscosity, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 2-2
<Step (3) -Operation (a1)>
Since the mesopentad fraction of the polypropylene obtained in Example 2-1 was still higher than the target value of 49.0%, the polymerization reaction was carried out by changing the triisobutylaluminum supplied to the reactor to 100 mmol / h. . When the mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured, it was 49.2 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.63 dL / g, the intrinsic viscosity was not changed, and the stereoregularity could be controlled while maintaining the molecular weight of the polypropylene. I was able to get it.

Example 2-3
<Step (3) -Operation (b1)>
Since the target polypropylene was obtained in Example 2-2, a manufacturing operation was then performed with a target of 50.0% of different mesopentad fractions. Since the regularity was higher than the target, the polymerization reaction was carried out by changing the triisobutylaluminum supplied to the reactor to 50 mmol / h. When the mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured, it was 49.2 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.64 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 2-4
<Step (3) -Operation (b1)>
Since the mesopentad fraction of the polypropylene obtained in Example 2-3 was still higher than the target value of 50.0%, the polymerization reaction was carried out by changing the triisobutylaluminum supplied to the reactor to 25 mmol / h. . The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 50.1 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.63 dL / g and the intrinsic viscosity was not substantially changed, and a target stereoregular polypropylene could be obtained.

Comparative Example 1
In the following manner, polypropylene whose mesopentad fraction was controlled to 49.0% (target value) was produced.
<Step (1)>
A 200 L stainless steel reactor equipped with a stirrer was supplied with n-heptane at 25 L / h and triisobutylaluminum at 25 mmol / h, and dimethylanilinium tetrakispentafluorophenylborate and (1,2 ′ -Dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilylmethylindenyl) zirconium dichloride, triisobutylaluminum and propylene in a molar ratio of 1: 7.5: 160. The catalyst component was continuously fed at 1.5 μmol / h in terms of zirconium.
The polymerization temperature was set to 60 ° C., triisobutylaluminum was supplied to the reactor at 25 mmol / h, the hydrogen concentration in the gas phase of the reactor was 15 mol%, and the total pressure in the reactor was 1.0 MPa (G) Thus, hydrogen and propylene passed through a purification column were continuously supplied to carry out the polymerization reaction for 120 minutes. The same purification column as that used in Example 1-1 was used.

<Step (2)>
The polypropylene obtained by removing n-heptane as a solvent was measured for mesopentad fraction [mmmm] and found to be 51.3 mol%. Moreover, it was 0.6 dL / g when intrinsic viscosity ((eta)) was measured.

<Step (3) -Comparison Operation>
Since the mesopentad fraction is higher than the target value of 49.0%, the propylene concentration in the gas phase portion of the reactor is reduced by reducing the amount of propylene supplied so that the total pressure is maintained at 0.9 MPa (G). The polymerization reaction was carried out by reducing the content from 77.8 mol% to 58.8 mol%. When the mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured, it was 49.1 mol%. Moreover, it was 0.4 dL / g when intrinsic viscosity ((eta)) was measured. As a result, by reducing the propylene concentration in the reactor, the stereoregularity of polypropylene can be controlled, but the intrinsic viscosity is reduced by 0.2 dL / g, and the stereoregularity is maintained while maintaining the molecular weight of polypropylene. I can't control it.

Example 3-1
In the following manner, polypropylene whose mesopentad fraction was controlled to 47.0% (target value) was produced.
<Step (1)>
(Preliminary polymerization)
To a 1 L autoclave equipped with a stirrer was added 196 mL of meta-xylene that had been thoroughly bubbled with nitrogen at room temperature under a nitrogen stream. Thereafter, while stirring, 4.5 mL of 2M heptane solution of triisobutylaluminum (addition amount of triisobutylaluminum: 9 mmol), (1,2'-dimethylsilylene) (2,1'-dimethylsilylene) -bis (3-trimethylsilyl) 40 mL of 30 mM toluene slurry of methylindenyl) zirconium dichloride (metallocene complex addition amount: 1.2 mmol), 60 mL of 30 mM toluene slurry of dimethylanilinium tetrakis (pentafluorophenyl) borate (addition amount of boron compound: 1.8 mmol) in order added. Thereafter, propylene was introduced to 0.05 MPa, the temperature was raised to 30 ° C., and prepolymerization was started. After 15 minutes, propylene introduction was stopped, and the mixture was further stirred for 30 minutes to obtain a catalyst solution containing the catalyst 1 (catalyst concentration: 4 mmol / L). As a result of calculating from the consumed propylene flow rate of 5.6 L, the amount of polypropylene produced in the prepolymerization was 10.5 g.

(Polymerization reaction)
To a 1 L autoclave, 400 mL of n-heptane was added at 25 ° C. under a nitrogen stream, and 1.0 mL of a 2M heptane solution of triisobutylaluminum (addition amount of triisobutylaluminum: 2.0 mmol) was added. After stirring for 1 minute, hydrogen was introduced to 0.05 MPa and propylene to a total pressure of 0.65 MPa, and the temperature was raised to 70 ° C. over about 3 minutes while stirring. After reaching the predetermined pressure and temperature, 0.05 mL of the catalyst solution containing the catalyst 1 (addition amount of catalyst 1: 0.2 μmol) was added, and polymerization was performed for 30 minutes. Thereafter, 5 mL of ethanol was added to stop the polymerization reaction. After depressurization, the resulting polymerization solution was dried at 80 ° C. under reduced pressure to obtain polypropylene.

<Step (2)>
The polypropylene obtained by removing n-heptane as a solvent was measured for mesopentad fraction [mmmm] and found to be 43.8 mol%. Moreover, it was 0.50 dL / g when intrinsic viscosity ((eta)) was measured.

<Step (3) -Operation (b1)>
Since the mesopentad fraction was lower than the target value of 47.0%, the polymerization reaction was carried out by changing the addition amount of the 2M heptane solution of triisobutylaluminum in the polymerization reaction to 0.4 mL (0.8 mol). The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 45.1 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.53 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 3-2
<Step (3) -Operation (b1)>
Since the mesopentad fraction of the polypropylene obtained in Example 3-1 is still lower than the target value of 47.0%, the addition amount of 2M heptane solution of triisobutylaluminum in the polymerization reaction was 0.2 mL (addition of triisobutylaluminum). The amount was changed to 0.4 mol) to carry out the polymerization reaction. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 46.8 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.59 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 3-3
<Step (3) -Operation (b1)>
Since the mesopentad fraction of the polypropylene obtained in Example 3-2 is still lower than the target value of 47.0%, the addition amount of 2M heptane solution of triisobutylaluminum in the polymerization reaction was changed to 0.05 mL (addition of triisobutylaluminum). The amount was changed to 0.1 mol), and a polymerization reaction was performed. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 47.1 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.60 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 4-1
Polypropylene with a mesopentad fraction controlled to 42.0% (target value) was produced as follows.
<Step (1)>
Except that the addition amount of 2M heptane solution of triisobutylaluminum was changed to 0.025 mL (triisobutylaluminum addition amount: 0.05 mmol) in the polymerization reaction of Example 3-1, and the reaction temperature was changed to 80 ° C. Polymerization was carried out in the same manner as in step (1) of Example 3-1.

<Step (2)>
The polypropylene obtained by removing n-heptane as a solvent was measured for mesopentad fraction [mmmm] and found to be 44.2 mol%. Moreover, it was 0.37 dL / g when intrinsic viscosity ((eta)) was measured.

<Step (3) -Operation (a1)>
Since the mesopentad fraction was higher than the target value of 42.0%, the polymerization reaction was carried out by changing the addition amount of the 2M heptane solution of triisobutylaluminum in the polymerization reaction to 0.1 mL (0.2 mol). When the mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured, it was 43.7 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.39 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 4-2
<Step (3) -Operation (a1)>
Since the mesopentad fraction of the polypropylene obtained in Example 4-1 is still higher than the target value of 42.0%, the addition amount of the 2M heptane solution of triisobutylaluminum in the polymerization reaction was 0.2 mL (addition of triisobutylaluminum). The amount was changed to 0.4 mol) to carry out the polymerization reaction. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 43.5 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.36 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

Example 4-3
<Step (3) -Operation (a1)>
Since the mesopentad fraction of the polypropylene obtained in Example 4-2 is still higher than the target value of 42.0%, the addition amount of the 2M heptane solution of triisobutylaluminum in the polymerization reaction was 0.4 mL (addition of triisobutylaluminum). The amount was changed to 0.8 mol), and a polymerization reaction was performed. The mesopentad fraction [mmmm] of the polypropylene obtained at this time was measured and found to be 42.1 mol%. Further, when the intrinsic viscosity (η) was measured, it was 0.32 dL / g, and the intrinsic viscosity was not substantially changed, and it was found that the stereoregularity could be controlled while maintaining the molecular weight of polypropylene.

  According to the present invention, it is possible to produce a propylene polymer whose stereoregularity is more precisely controlled without changing the molecular weight of the polymer. The propylene polymer produced by the present invention is useful for various applications including inks, paints, emulsions, and toner release agents.

Claims (4)

A method for producing a propylene polymer in which stereoregularity is controlled without changing the molecular weight of the polymer,
Step (1): A polymerization step that is a continuous polymerization method in which hydrogen and propylene are continuously supplied into the reactor, and propylene is polymerized in the presence of a continuously supplied transition metal complex and organoaluminum to produce a propylene polymer. ,
Step (2): Step of measuring the stereoregularity (mmmm%) of the propylene polymer obtained in Step (1), and Step (3): Stereoregularity of the propylene polymer measured in Step (2) When the measured value is compared with a preset target value and the measured value is higher than the target value, at least one of the following operations (a1) to (a 3 ) is performed, and the measured value is lower than the target value look including a control step of at least one operation of the following (b1) ~ (b 3), performed in the step (1) to,
Repeating step (2) and step (3) until the measured value of step (2) matches the preset target value;
A method for producing a propylene polymer.
(A1) Increasing the concentration of organoaluminum in the reactor (a2) Decreasing the partial pressure of hydrogen supplied to the polymerization step and raising the polymerization temperature (a3) Impurities contained in propylene supplied to the polymerization step Increase the amount of
(B1) Reducing the concentration of organoaluminum in the reactor (b2) Increasing the partial pressure of hydrogen supplied to the polymerization step and lowering the polymerization temperature (b3) Impurities contained in propylene supplied to the polymerization step Reduce the amount of The method for producing a propylene polymer according to claim 1, wherein the organoaluminum is at least one selected from the group consisting of a trialkylaluminum, a dialkylaluminum halide, and an organic alumoxane. The method for producing a propylene polymer according to claim 1 or 2, wherein the transition metal complex is a chelate complex or a metallocene complex. The manufacturing method of the propylene polymer in any one of Claims 1-3 whose said transition metal complex is a bibridged metallocene complex represented by the following general formula (I).


[Wherein M represents a metal element of Groups 3 to 10 of the periodic table, and E1 and E2 represent a substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, a heterocyclopentadienyl group, and a substituted heterocyclopenta, respectively. A ligand selected from a dienyl group, an amide group, a phosphide group, a hydrocarbon group and a silicon-containing group, which forms a cross-linked structure via A1 and A2, and they are the same as each other X may be different, X represents a σ-bonding ligand, and when there are a plurality of X, a plurality of Xs may be the same or different and are cross-linked with other X, E1, E2 or Y Also good. Y represents a Lewis base, and when there are a plurality of Ys, the plurality of Ys may be the same or different, may crosslink with other Y, E1, E2 or X, and A1 and A2 are in two coordination positions. A divalent bridging group for bonding a child, a hydrocarbon group having 1 to 20 carbon atoms, a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, a silicon-containing group, a germanium-containing group, a tin-containing group, -O- _{, -CO -, - S -,} - SO 2 -, - Se -, - NR 1 -, - PR 1 -, - P (O) R 1 -, - BR 1 - or -AlR ¹ - indicates, R ¹ represents a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms or a halogen-containing hydrocarbon group having 1 to 20 carbon atoms, which may be the same as or different from each other. q represents an integer of 1 to 5 and represents [(M valence) -2], and r represents an integer of 0 to 3. ]