JP2775706B2 - Method for producing syndiotactic poly-α-olefin having wide molecular weight distribution - Google Patents

Description

The present invention relates to a method for producing syndiotactic poly-α-olefin using a highly active polymerization catalyst. More specifically, the present invention relates to a syndiotactic poly-α-olefin having a broad molecular weight distribution in the presence of a catalyst comprising two or more transition metal compounds and an aluminoxane, and a method for producing the same.

[Conventional technology]

Methods for producing poly-α-olefins in the presence of a catalyst comprising a transition metal compound and an aluminoxane are known. When such a catalyst is used, a poly-α-olefin having a narrow molecular weight distribution, that is, Mw / Mn of 2 to 3 can be obtained.

JP-A-60-35008 discloses that poly-α-olefin having a wide molecular weight distribution is obtained by polymerizing ethylene or copolymerizing ethylene and α-olefin using a catalyst comprising at least two transition metal compounds and aluminoxane. Although a production method is disclosed, it does not describe a method for producing a syndiotactic poly-α-olefin.

It has long been known that syndiotactic poly-α-olefins can be obtained by a low-temperature polymerization method using a catalyst comprising a vanadium compound and an organoaluminum.However, in the conventional method, the tacticity of the obtained polymer is poor and the original It was hard to say that it was characteristic of syndiotactic poly-α-olefins.

On the other hand, JAEwen et al. Reported that a catalyst comprising a transition metal compound having an isopropylidene (cyclopentadienyl-1-fluorenyl) group as a ligand and an aluminoxane had a syndiotactic pentad fraction exceeding 0.8. It was discovered for the first time that a polypropylene with good tee could be obtained. (J.Am.chem.soc., 199
8, 110, 6255-6256).

However, GPC (gel permeation chromatography) of the resulting syndiotactic polypropylene
Since the molecular weight distribution index Mw / Mn measured in step 2 is 2 to 3, the fluidity of the molten resin is poor, and the melt tension of the molten resin is low, so that it is easy to break the thread when it is extruded to form a thread. It was difficult to make a good sheet due to sagging.

A catalyst comprising a transition metal compound having at least one fluorenyl group as a ligand and an aluminoxane similar to the method of JAEwen et al. Is disclosed in JP-A-64-66214.
There is no description of a transition metal compound in which a compound in which a cyclopentadienyl group and a fluorenyl group are bonded as a ligand as in the present invention.

As disclosed in JP-A-64-66214, even if a fluorenyl group is simply used as a transition metal and an α-olefin is polymerized using a transition metal compound and an aluminoxane as a catalyst, a syndiotactic compound produced by the catalyst system of the present invention is obtained. Poly-α-
No olefin is obtained and is a completely different catalyst system.

[Problems to be solved by the invention]

The above-mentioned method of JAEwen et al. Has a good activity per transition metal, and is a method excellent in syndiotacticity of the obtained polymer.However, the molecular weight distribution of the obtained polymer is narrow, and many methods such as an extrusion molding method are used. There was a problem that the workability was poor and unfavorable in use.

[Means for solving the problem]

Means for Solving the ProblemsThe present inventors have solved the above-mentioned problems and have intensively studied a method for producing a poly-α-olefin having a wide molecular weight distribution and a good syndiotacticity with good processability with high productivity and high activity. The invention has been completed.

That is, the present invention provides a method for polymerizing or copolymerizing an α-olefin using a catalyst comprising (A) a transition metal compound and (B) an aluminoxane, wherein (A) a cyclopentadienyl group and a fluorenyl group are used as the transition metal compound. Of the Periodic Table with Ligand of Compounds Linked through a Hydrocarbon Group
IV Periodic table in which at least one of the transition metal compounds of Group IVB is used in combination, and at least one of the compounds has a ligand in which a cyclopentadienyl group and a fluorenyl group are bonded via a cycloalkylidene group as a ligand. A process for producing a syndiotactic poly-α-olefin having a wide molecular weight distribution, characterized by being a transition metal compound of Group IVB.

Molecular weight distribution index measured by GPC (gel permeation chromatography) of syndiotactic poly-α-olefin obtained by employing the method of the present invention
Mw / Mn is 4 or more, especially about 4 to 20, and the molecular weight distribution is widened, and a syndiotactic poly-α-olefin having good fluidity and processability of the melt can be obtained.

The transition metal compound of Group IVB of the Periodic Table IV having a compound in which a cyclopentadienyl group and a fluorenyl group are bonded via a hydrocarbon group used in the present invention is represented by the general formula (I) It is a compound shown by these. A ¹ in the general formula (I) is a cyclopentadienyl group, and A ² is a fluorenyl group. A ³
Is an alkylene group, an alkylidene group, a cycloalkylidene group, preferably an alkylidene group, a cycloalkylidene group, and more preferably a cycloalkylidene group.
R ¹ and R ² are an aryl group, an alkyl group, a cycloalkyl group, a halogen atom, a hydrogen atom, or a silyl group. M is titanium, zirconium or hafnium, preferably zirconium or hafnium.

Specific examples of the transition metal compound which is the component (A) in the present invention include, for example, ethylene (cyclopentadienyl-1-fluorenyl) titanium dimethyl, ethylene (cyclopentadienyl-1-fluorenyl) zirconium dimethyl, ethylene (cyclo Pentadienyl-1-
Fluorenyl) hafnium dimethyl, ethylene (cyclopentadienyl-1-fluorenyl) titanium dichloride, ethylene (cyclopentadienyl-1-fluorenyl) zirconium dichloride, ethylene (cyclopentadienyl-1-fluorenyl) haunium dichloride, isopropylidene (Cyclopentadienyl-1-fluorenyl) titanium dimethyl, isopropylidene (cyclopentadienyl-1-fluorenyl) zirconium dimethyl, isopropylidene (cyclopentadienyl-1-fluorenyl) haunium dimethyl, isopropylidene (cyclopentadiene) Enyl-1-fluorenyl)
Titanium dichloride, isopropylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-1-fluorenyl) haunium dichloride, cyclohexylidene (cyclopentadienyl-1-fluorenyl) titanium dichloride, Isopropylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride, isopropylidene (cyclopentadienyl-1-fluorenyl) hafnium dichloride, cyclobutylidene (cyclopentadienyl-1-fluorenyl) titanium dimethyl, cyclobutylidene ( Cyclopentadienyl-1-
Fluorenyl) zirconium dimethyl, cyclobutylidene (cyclopentadienyl-1-fluorenyl) hafnium dimethyl, cyclobutylidene (cyclopentadienyl-1-fluorenyl) titanium dichloride, cyclobutylidene (cyclopentadienyl-1-fluorenyl) Zirconium dichloride, cyclobutylidene (cyclopentadienyl-1-fluorenyl) hafnium dichloride, cyclohexylidene (cyclopentadienyl-
1-fluorenyl) titanium dimethyl, cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dimethyl, cyclohexylidene (cyclopentadienyl-1-fluorenyl) hafnium dimethyl,
Cyclohexylidene (cyclopentadienyl-1-fluorenyl) titanium dichloride, cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride, cyclohexylidene (cyclopentadienyl-1-fluorenyl) hafnium dichloride and the like are mentioned. Can be.

A synthetic route of a transition metal compound having a cycloalkylidene (cyclopentadienyl-1-fluorenyl) group as a ligand is described below, for example, when a cyclohexylidene (cyclopentadienyl-1-fluorenyl) group is used as a ligand. Is shown as

_{C 13 H 10 + MeLi → LiC} 13 H 9 + CH 4 ...... (1) LiC 13 H 9 + C 6 H 10 = C 5 H 4 + HCl → C 6 H 10 (C 5 H5) C 13 H 9 + LiCl ...... (2 ) C ₆ H ₁₀ (C ₅ H ₅ ) C ₁₃ H ₉ +2 BuLi → Li ₂ [C ₆ H ₁₀ (C ₅ H ₄ ) C ₁₃ H ₈ ] …… (3) Li ₂ [C ₆ H ₁₀ (C ₅ H ₄ ) C ₁₃ H ₈ ] + MX ₄ → [C ₆ H ₁₀ (C ₅ H ₄ ) C ₁₃ H ₈ ] MX ₂ (where X is a halogen atom, M is titanium, zirconium, The production method of 6,6-pentamethylenefulvene, ie, C ₆ H ₁₀ ＝ C ₅ H ₄ , used in the above reaction formula (2) is known.
(J. Org. Chem., 1984.49.1849-1853).

Similar to cyclohexylidene (cyclopentadiene-1-fluorene), cycloalkylidene having 4 to 10 carbon atoms (cyclopentadiene-1-fluorene) such as cyclobutenylidene (cyclopentadiene-1-fluorene), cyclodecanylidene ( Cyclopentadiene-1-
Fluorene) can also be synthesized.

When cycloalkylidene (cyclopentadiene-1-fluorene) is used as the ligand, there is no change in the catalytic activity with time, and particularly preferable results are obtained.

A method for synthesizing a transition metal compound having cyclohexylidene (cyclopentadiene-1-fluorene) obtained according to the above reaction route as a ligand will be described below.

Such a dialkylmetallation of cycloalkylidene (cyclopentadiene-1-fluorene) can be carried out by reacting cycloalkylidene (cyclopentadiene-1-fluorene) with an alkali metal or organic alkali metal compound. As a solvent used at this time, diethyl ether, tetrahydrofuran, ethers such as dimethoxyethane, heptane, hexane,
Saturated hydrocarbon compounds such as pentane can be used. Cycloalkylidene (cyclopentadiene-1-
The ratio of the alkali metal or organic alkali metal compound to fluorene) is 2.0 to 10.0, preferably 2.0 to 4.0.
0 mole ratio, reaction temperature is -100 to 150 ° C, preferably -90 ° C
It is in the range of ~ 90 ° C.

For example, cycloalkylidene (cyclopentadiene-1-fluorene) is dilithiated with alkyllithium by the above method to obtain cycloalkylidene (cyclopentadienyl-1-fluorenyl) dilithium, which is used in the next reaction.

Examples of the solvent used in the reaction of Li ₂ [A ³ (C ₅ H ₄ ) C ₁₃ H ₈ ] (A ³ hydrocarbon residue) with MX ₄ include halogen hydrocarbons such as chloroform and methylene chloride, and pentane In addition to saturated hydrocarbons such as hexane, heptane and cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, ethers such as diethyl ether and tetrahydrofuran can be used.

The molar ratio of Li ₂ [A ³ (C ₅ H ₄ ) C ₁₃ H ₈ ] / MX _{4 in} the reaction is 0.9 to 3.0, preferably 1.0 to 1.5. The reaction temperature ranges from -100 ° C to 100 ° C, preferably from -90 ° C to 50 ° C. [A ³ (C ₅ H ₄ ) C ₁₃ H ₈ ] MX ₂
X in (X is a halogen atom) is more easily reacted with an organolithium compound represented by the general formula RLi (wherein R represents a hydrocarbon group having 1 to 10 carbon atoms), for example, an alkyllithium such as methyllithium. Substituted with an alkyl group.

As the solvent used at that time, for example, halogenated hydrocarbons such as chloroform and methylene chloride, pentane, hexane, heptane, saturated hydrocarbons such as cyclohexane, benzene, toluene, aromatic hydrocarbons such as xylene, diethyl Ethers such as ether and tetrahydrofuran can also be used. The ^{_{[A 3 (C 5 H 4}} ) C 13 H 8] when performing the reaction using the molar ratio of RLi against MX ₂ is 1.0 to 100, preferably 1.0 to 3.0. The reaction temperature ranges from -100 ° C to 100 ° C, preferably from -90 ° C to 80 ° C.

The produced compound (I) can be purified by recrystallization or sublimation.

According to the above method, cycloalkylidene (cyclopentadiene-1-fluorene) having 4 to 10 carbon atoms, for example, cyclobutenidene (cyclopentadiene-1-fluorene), cyclohexylidene (cyclopentadiene-1-fluorene) is used.
Various transition metal compounds having fluorene), cyclodecanelidene (cyclopentadiene-1-fluorene) or the like as a ligand can be synthesized.

A method of combining two or more of the above transition metal compounds, for example, a combination of different metals such as zirconium and hafnium, and titanium and zirconium, or a combination of transition metal compounds having the same metal but different ligands may be used. Can be. In this case, it is important to use, as at least one kind, a transition metal compound belonging to Group IVB of the periodic table IVB having a compound in which a cyclopentadienyl group and a fluorenyl group are bonded via a cycloalkylidene group as a ligand. . The number of moles of the transition metal compound used is the smallest among the transition metal compounds used.
The molar ratio of the other transition metal compound used is 1 to 200 moles, and preferably 1 to 100 moles.

The aluminoxane as the component (B) in the catalyst used in the present invention has a general formula Wherein R is a hydrocarbon group having 1 to 3 carbon atoms, and n is an integer of 2 or more. In particular, R is a methylaminoxan having a methyl group, and n is 5 or more, preferably More than 10 are used.

The method for producing the aluminoxane is known, and is, for example, a method of adding a trialkylaluminum to a salt containing water of crystallization (eg, copper sulfate hydrate, magnesium chloride hydrate) in a hydrocarbon and reacting the salt, In the method, a method of directly reacting a trialkylaluminum with water can be exemplified.

The catalyst component (A) and / or (B) may be used as it is or by being supported on a known carrier that supports a Ziegler catalyst.

The use ratio of aluminoxane to the total metal in the transition metal catalyst is 10 to 10,000 mole times, usually 50 to 5000 mole times. In the present invention, α-
Specific examples of the olefin include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-octadecene. Α-olefins having 3 to 25 carbon atoms can be exemplified.

In the present invention, copolymers of ethylene or α-olefin having about 2 to 25 carbon atoms such as propylene and ethylene, propylene and 1-butene, as long as they exhibit not only homopolymerization of α-olefin but also syndiotactic structure. It can also be used when manufacturing.

As the hydrocarbon medium used in the polymerization or copolymerization, for example, butane, pentane, hexane, heptane,
In addition to saturated hydrocarbons such as octane, nonane, decane, cyclopentane and cyclohexane, benzene, toluene,
Α-olefins, which are aromatic hydrocarbon raw materials such as xylene, can also be used.

The polymerization conditions are not particularly limited, and a solvent polymerization method using an inert hydrocarbon medium (suspension polymerization, solution polymerization), a bulk polymerization method in which polymerization is performed under conditions substantially free of an inert hydrocarbon medium, a gas phase A polymerization method can also be used.

In general, the polymerization is carried out at a temperature of -100 to 200 ° C. and at a pressure of normal pressure to 100 kg / cm ² . Preferably -5
0 to 100 ° C, normal pressure to 50 kg / cm ² .

Further, in order to adjust the molecular weight of the polymer produced by the method of the present invention, polymerization can be carried out by adding a molecular weight regulator such as hydrogen.

〔Example〕

 Hereinafter, the present invention will be described with reference to examples.

Example 1 Synthesis of Transition Metal Compound Lithium isopropylidene (cyclopentadiene-1-fluorene) synthesized above was reacted with zirconium tetrachloride to obtain isopropylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride. . Similarly, by reacting a lithium salt of isopropylidene (cyclopentadiene-1-fluorene) with hafnium tetrachloride, isopropylidene (cyclopentadienyl-1-fluorenyl) hafnium dichloride was obtained. Cyclohexylidene (cyclopentadiene-1-fluorene) was lithiated and reacted with zirconium tetrachloride to synthesize cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride by the following method.

[Cyclohexylidene (cyclopentadiene-1-fluorene)] 11.4 g of fluorene was dissolved in 150 ml of tetradrofuran in a 300 ml glass flask which was sufficiently purged with nitrogen. To this solution was added 70 mmol of a methyllithium ether solution.
It was added dropwise at 78 ° C. After completion of the dropwise addition, the reaction solution was raised to room temperature, and stirred at that temperature for 3 hours. To this reaction solution, 10 g of 6,6-pentamethylenefulvene diluted with 50 ml of tetrahydrofuran (J. Org, Chem., 1984.49.1849-185).
(Synthesized by the method described in 3) was added dropwise. After completion of the dropwise addition, the reaction temperature was raised to room temperature, and stirring was continued for another 10 hours. The reaction was stopped by charging 200 ml of 3.6% aqueous hydrochloric acid, and the ether layer was washed with water and evaporated to dryness to obtain a yellow-white solid. 100 ml of this solid ascent
Then, 12.4 g of white cyclohexylidene (cyclopentadiene-1-fluorene) was obtained.

The physical properties of this compound are shown below.

Elemental analysis value C ₂₄ H ₂₄ CH Calculated value (%): 92.31 7.69 Observed value (%): 92.22 7.72 [Cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium chloride] Cyclohexylidene (cyclo) synthesized above By dilithifying pentadiene-1-fluorene) with n-butyllithium, a dilithium salt of cyclohexylidene (cyclopentadiene-1-fluorene) was prepared. Next, 5.5 g of zirconium tetrachloride was suspended in 100 ml of methylene chloride in a 500 ml glass flask sufficiently purged with nitrogen. 300 ml of a methylene chloride solution of cyclohexyldene (cyclopentadienyl-1-fluorenyl) dilithium dissolved at -78 ° C was introduced into the suspension at -78 ° C. −7
After stirring at 8 ° C. for 4 hours, the temperature was raised to room temperature, and the reaction was continued at that temperature for another 15 hours. The reddish-brown solution containing the white precipitate of lithium chloride was filtered off, and the reddish-brown filtrate was concentrated, and the solution was dried at -30 ° C.
After cooling for 24 hours, 2.3 g of red crystals of cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium chloride was obtained.

The physical properties of this compound are shown below.

Elemental analysis value C ₂₄ H ₂₂ ZrCl ₂ CHCl Calculated value (%): 61.00 4.66 15.00 Actual value (%): 60.98 4.66 15.01 Similarly, lithium salt of cyclohexylidene (cyclopentadiene-1-fluorene) and tetrachloride By reacting haunium, cyclohexylidene (cyclopentadienyl-1-fluorenyl) hafnium dichloride was obtained.

(Adjustment of catalyst solution)

Catalyst solutions A, B, C, and D were prepared as follows.

Catalyst solution A 10 mg of isopropylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride synthesized above was dissolved in 10 mg of toluene. 1.3 g of methylaluminoxane (polymerization degree: 17.7) manufactured by Tosoh Akzo Co., Ltd. was further added to this solution to prepare a purple catalyst solution A.

Catalyst solution B 20 mg of isopropylidene (cyclopentadienyl-1-fluorenyl) hafnium dichloride synthesized above was dissolved in 20 ml of toluene. A red catalyst solution B was prepared by adding 2.2 g of methylaluminoxane to this solution.

Catalyst solution C Cyclohexylidene (cyclopentadienyl-1-fluorenyl) zirconium dichloride 10 mg synthesized above
Was dissolved in 10 mg of toluene. 1.2 g of ethylaluminoxane was added to this solution to prepare a purple catalyst solution C.

Catalyst solution D 20 mg of cyclohexylidene (cyclopentadiel-1-fluorenyl) hafnium dichloride synthesized above was dissolved in 20 ml of toluene. Red catalyst solution D was prepared by adding 2.1 g of methylaluminoxane to this solution.

(Polymerization method)

After replacing the autoclave with nitrogen, pentane
The catalyst solution C prepared above was added in an amount of 9.5 × 10 ^-4 mmol in terms of zirconium atoms, and the catalyst solution D was added in an amount of 5.7 × 10 ^-3 mmol in terms of hafnium atoms. Polymerization was carried out at 40 ° C. for 1 hour while maintaining the inside of the system at 9 kg / cm ² by adding propylene. After polymerization, take out the slurry, add heptane 1,
Filtration and drying gave 116.3 g of syndiotactic polypropylene. When the filtrate was distilled off under reduced pressure to remove the solvent, the solvent-soluble component was 0.1 g. Intrinsic viscosity (hereinafter referred to as η) measured with a tetralin solution of powder at 135 ° C.
Abbreviated as) is 2.11 dl / g, Mw / Mn measured by GPC is 6.4,
^The syndiotactic pentad fraction measured by ¹³ C-NMR was 0.90.

Comparative Example 1 Polymerization was carried out in the same manner as in [Polymerization method] of Example 1, except that only catalyst solution A obtained in [Preparation of catalyst solution] of Example 1 was used in an amount of 4.6 × 10 ⁻³ mmol in terms of zirconium atoms. Was. The obtained polymer has a solvent insoluble content of 122.4 g and a soluble content of 0.2 g.
Met. The η powder 1.36, Mw / Mn syndiotactic pentad fraction measured by 2.2 ¹³ C-NMR was 0.90.

Comparative Example 2 Polymerization was carried out in the same manner as in [Polymerization method] of Example 1 except that only Catalyst solution B obtained in [Preparation of catalyst solution] of Example 1 was used in an amount of 4.6 × 10 ^-3 mmol in terms of hafnium atoms. Was. The resulting polymer had a solvent insoluble content of 35.8 g and a soluble content of 0.1
g. The η of the powder was 4.74 dl / g and the Mw / Mn was 2.8.

Comparative Example 3 Polymerization was carried out in the same manner as in [Polymerization method] of Example 1 except that only catalyst solution C obtained in [Preparation of catalyst solution] of Example 1 was used in an amount of 4.6 × 10 ⁻³ mmol in terms of zirconium atoms. Was. The obtained polymer had a solvent soluble content of 109.8 g and a soluble content of 0.1 g. The η of the powder was 1.20 dl / g, and the Mw / Mn was 2.1.

Comparative Example 4 Polymerization was carried out in the same manner as in [Polymerization method] of Example 1 except that only Catalyst solution D obtained in [Preparation of catalyst solution] of Example 1 was used in an amount of 4.6 × 10 ^-3 mmol in terms of hafnium atom. Was. The obtained polymer has a solvent insoluble content of 41.7 g and a soluble content of 0.1 g.
Met. The η of the powder was 4.61 dl / g, and the Mw / Mn was 2.6.

Example 2 Catalyst solution A obtained in [Preparation of catalyst solution] of Example 1 was 2.3 × 10 ^-4 mmol in terms of zirconium atom, and catalyst solution C was used.
Was polymerized in the same manner as in [Polymerization method] of Example 1 except that 2.3 × 10 ^-3 mmol of zirconium atom was used. The obtained polymer has a solvent insoluble content of 120.5 g and a soluble content of 0.1 g.
Met. The η of the powder was 1.23 dl / g and the Mw / Mn was 4.1.

[Effects of the Invention] By performing the method of the present invention, an indiotactic poly-α-olefin having a wide molecular weight distribution can be produced with stable performance, which is extremely valuable industrially.

──────────────────────────────────────────────────続 き Continued on the front page Examiner Hitoshi Kobayashi (56) References JP-A-2-41303 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F 4/60-4 / 70 C08F 10/00-10/14 C08F 110/00-110/14 C08F 210/00-210/18

Claims (1)

(57) [Claims] 1. A method for polymerizing or copolymerizing an α-olefin using a catalyst comprising (A) a transition metal compound and (B) an aluminoxane, wherein (A) a cyclopentadienyl group and a fluorenyl group are used as the transition metal compound. Of the Periodic Table IV with a compound having a ligand bound via a hydrocarbon group as a ligand
Periodic Table IV B wherein at least two kinds of transition metal compounds of Group B are used in combination, wherein at least one kind is a compound in which a cyclopentadiene group and a fluorenyl group are bonded via a chloroalkylidene group as a ligand. A method for producing a syndiotactic-α-olefin having a wide molecular weight distribution, characterized in that the compound is a group IV transition metal compound.