JPH0714965B2 - Olefin Polymerization Method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for polymerizing olefin in the presence of a novel highly active polymerization catalyst. More specifically, it relates to a highly active polymerization method in which olefin is polymerized in the presence of a catalyst composed of a transition metal compound and aluminoxane.

[Conventional technology]

In the field of olefin polymerization, remarkable proposals have been made regarding so-called Ziegler catalysts comprising a combination of a transition metal compound and an organoaluminum compound, and they are widely used as an industrial process for producing olefin polymers. Further, recently, a method of using aluminoxane as an organoaluminum compound component has been proposed as a method for improving the polymerization activity of a Ziegler catalyst. For example, in JP-A-58-19309 and JP-A-59-95292,
It is described that a catalyst composed of a transition metal compound and aluminoxane is highly active in a polymerization reaction of olefin.

[Problems to be Solved by the Invention] As a result of further detailed study on the polymerization of olefin in the presence of a catalyst composed of a transition metal compound and an aluminoxane, the present inventors have found that the transition metal compound and a specific aluminoxane are used. The present inventors have found that the catalyst formed from is more highly active than the above-mentioned conventional catalysts, and arrived at the present invention.

[Means for Solving Problems] and [Operation] The present invention provides (A) a compound having a cyclopentadienyl group of a transition metal selected from the group consisting of titanium, zirconium, hafnium and vanadium, and (B) General formula [I] or general formula [II] obtained by reacting trialkylaluminum with water (Wherein R represents a hydrocarbon group and m represents an integer of more than 40) in the presence of a catalyst consisting of an aluminoxane. It is a summary.

The transition metal compound (A) as a catalyst constituent used in the method of the present invention is a compound of a transition metal selected from the group consisting of titanium, zirconium, hafnium and vanadium, and at least one, preferably two carbonized Having a hydrogen group, particularly preferably a cyclopentadienyl group,
And, it is preferably a transition metal compound having one halogen atom, particularly preferably two. Among these transition metal atoms, titanium or zirconium is preferable, and zirconium is particularly preferable because it has high activity. Specific examples of the hydrocarbon group include a methyl group, an ethyl group,
n-propyl group, isopropyl group, n-butyl group, sec
-Butyl group, tert-butyl group, isobutyl group, alkyl group such as neopentyl group, isopropenyl group, alkenyl group such as 1-butenyl group, cyclopentadienyl group,
It is a cycloalkadienyl group such as a methylcyclopentadienyl group or an aryl group such as a benzyl group or a neofoyl group, and specific examples of the halogen atom include fluorine, chlorine, bromine and iodine atoms. Further, specific examples of the transition metal compound include bis (cyclopentadienyl) dimethyl titanium, bis (cyclopentadienyl) diethyl titanium, bis (cyclopentadienyl) diisopropyl titanium, and bis (methylcyclopentadienyl). Dimethyl titanium, bis (cyclopentadienyl) methyl titanium monochloride, bis (cyclopentadienyl) ethyl titanium monochloride, bis (cyclopentadienyl)
Isopropyl titanium monochloride, bis (cyclopentadienyl) methyl titanium monobromide, bis (cyclopentadienyl) methyl titanium monoiodide, bis (cyclopentadienyl) titanium difluoride, bis (cyclopentadienyl) titanium dichloride, Titanium compounds such as bis (cyclopentadienyl) titanium dibromide, bis (methylcyclopentadienyl) titanium diiodide, bis (cyclopentadienyl) dimethylzirconium, bis (cyclopentadienyl) diethylzirconium, bis ( Methylcyclopentadienyl) diisopropylzirconium, bis (cyclopentadienyl) methylzirconium monochloride, bis (cyclopentadienyl) ethylzirconium monochloride, bis (cyclopentadienyl) methyl Zirconium monobromide, bis (cyclopentadienyl) methyl zirconium monoiodide, bis (cyclopentadienyl) zirconium difluoride, bis (cyclopentadienyl) zirconium dichloride, bis (cyclopentadienyl) zirconium dibromide, bis Zirconium compounds such as (cyclopentadienyl) zirconium monochloride, bis (cyclopentadienyl) zirconium diiodide, bis (cyclopentadienyl) dimethylhafnium, bis (cyclopentadienyl) methylzirconium monochloride, Bis (cyclopentadienyl)
Hafnium compounds such as zirconium dichloride and bis (cyclopentadienyl) vanadium dichloride can be exemplified.

The catalyst constituent aluminoxane (B) used in the method of the present invention is obtained by reacting trialkylaluminum with water, and is represented by the general formula [I] or the general formula [II]. (In the formula, R represents a hydrocarbon group, and m represents an integer of more than 40). In the aluminoxane, R is a methyl group, an ethyl group,
It is a hydrocarbon group such as a propyl group and a butyl group, preferably a methyl group, an ethyl group, particularly preferably a methyl group, and m is an integer exceeding 40, preferably an integer of 40 to 100. The following method can be exemplified as a method for producing the aluminoxane.

(1) A method in which a trialkylaluminum is added to a hydrocarbon medium suspension such as a compound containing adsorbed water or a salt containing water of crystallization, for example, a copper sulfate hydrate or an aluminum sulfate hydrate to react.

(2) A method in which steam is allowed to act on a benzene solution of trialkylaluminum.

(3) A method in which water is allowed to directly act on a trialkylaluminum in a medium such as benzene, toluene, ethyl ether, or tetrahydrofuran.

Of these, the method (1) is preferable. When m is 40 or less in the aluminoxane, the polymerization activity of the catalyst is lowered.

FIG. 1 shows the steps for preparing the catalyst used in the method of the present invention.

In the method of the present invention, specific examples of the olefin to be subjected to the polymerization reaction include ethylene, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene. , 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene and the like can be exemplified, and a mixed component of two or more kinds of these can also be subjected to polymerization.

In the method of the present invention, the olefin polymerization reaction is usually carried out in a hydrocarbon medium. Specific examples of the hydrocarbon medium include butane, isobutane, pentane, hexane, octane, decane, dodecane, hexadecane, octadecane, and other aliphatic hydrocarbons, cyclopentane, methylcyclopentane, cyclohexane, cyclooctane, and other alicyclic groups. In addition to hydrocarbons, aromatic hydrocarbons such as benzene, toluene, and xylene, petroleum fractions such as gasoline, kerosene, and light oil, olefin as a raw material also serves as a hydrocarbon medium. Of these hydrocarbon media, aromatic hydrocarbons are preferred.

In the method of the present invention, a liquid phase polymerization method such as a suspension polymerization method or a solution polymerization method is usually adopted, but a gas phase polymerization method can also be adopted. The temperature during the polymerization reaction is usually -50
To 230 ° C, preferably -20 to 200 ° C.

When the method of the present invention is carried out by a liquid phase polymerization method, the proportion of the transition metal compound used is usually 10 ^-9 to 10 ^-2 gram atom /, preferably the concentration of the transition metal atom in the polymerization reaction system.
It is in the range of 10 ⁻⁸ to 10 ⁻³ gram atom /. The aluminoxane content is usually in the range of 10 ^-4 to 10 ^-1 gram atom /, preferably 10 ^-3 to 5 × 10 ^-2 gram atom /, as the concentration of aluminum atoms in the polymerization reaction system. And the ratio of aluminum metal atom to transition metal atom in the polymerization reaction system is usually 4 to 10 ⁸ ,
It is preferably in the range of 10 to 10 ⁶ . The molecular weight of the copolymer can be adjusted by hydrogen and / or the polymerization temperature.

In the method of the present invention, the polyolefin mixture can be obtained by treating the polymerization reaction mixture after the polymerization reaction according to a conventional method.

〔The invention's effect〕

According to the method of the present invention, the polymerization activity of olefin is excellent as compared with the conventional catalyst composed of a transition metal compound and aluminoxane. The catalyst system is characterized in that the polymerization activity is long-lasting, and multistep polymerization can also be adopted.

〔Example〕

Next, the method of the present invention will be specifically described with reference to examples.

Example 1 [Preparation of aluminoxane] Water was evaporated from an Al ₂ (SO ₄ ) ₃ aqueous solution to obtain solid Al ₂ (S 4
O ₃ ) ₃ hydrate, which was further depressurized at 40 ° C (460 mmH
g) Dried to obtain Al ₂ (SO ₄ ) ₃ · 14H ₂ O.

A 200 ml flask that had been sufficiently purged with argon was charged with 7.4 g of Al ₂ (SO ₄ ) ₃ · 14H ₂ O obtained above and 25 ml of toluene.
After cooling to ° C, 100 mmol of trimethylaluminum diluted with 25 ml of toluene was added dropwise. Next, the temperature was raised to 40 ° C., and the reaction was continued at that temperature for 8 days. After the reaction, solid-liquid separation was performed by filtration, and toluene was further removed from the separated liquid to obtain 3.5 g of a white solid aluminoxane. The molecular weight measured by the freezing point depression method using benzene as a solvent was 3400, and the m value of the aluminoxane was 57. In the polymerization, it was redissolved in toluene and used.

[Overlap]

500 ml of purified toluene was charged into a glass autoclave having an internal volume of 1 that had been sufficiently replaced with nitrogen, and the temperature was raised to 85 ° C.
Next, aluminoxane equivalent to 2.5 mg of aluminum atom and zirconium atom of 1.25
After charging bis (cyclopentadienyl) zirconium dichloride dissolved in toluene corresponding to x10 ^-4 milligram atom, ethylene was introduced, and polymerization was carried out at 90 ° C for 1 hour under normal pressure. After the polymerization was completed, separate the polymer slurry and keep it at 80 ℃.
And dried under reduced pressure overnight. Polymer yield after drying is 13.6g
And the activity per unit zirconium was 10.9 × 10 ⁴ g-polymer / milligram atom-Zr. The MFR of this polymer was 0.35 g / 10 min.

Comparative Example 1 Synthesis of the aluminoxane of Example 1 was repeated except that the reaction time was 8 hours. The molecular weight of the aluminoxane obtained was 970, and the m value of the aluminoxane was 15. Polymerization of ethylene was carried out using this aluminoxane in the same manner as in Example 1. As a result, the polymer yield was 9.1 g, and the activity was 7.3 × 10 ⁴ g polymer / milligram atom-Zr. Polymer MFR
Was 0.42g / 10min.

Example 2 250 ml of purified toluene was charged into a glass autoclave having an internal volume of 500 ml, which had been sufficiently replaced with nitrogen, and a mixed gas of ethylene and propylene (90 / hr and 10 / hr, respectively) was circulated and kept at 40 ° C for 10 minutes. did. Then, 1.25 × 10 6 in terms of aluminoxane and zirconium atom, which were synthesized in Example 1 and corresponded to 1.25 mg of atom in terms of aluminum atom.
Polymerization was initiated by charging bis (cyclopentadienyl) zirconium dichloride corresponding to ^-3 milligram atoms.
After carrying out atmospheric pressure polymerization at 40 ° C. for 30 minutes, isopropanol was added to terminate the polymerization. The produced polymer slurry was added to a large amount of a methanol / acetone mixed solution to precipitate a polymer, which was dried under reduced pressure at 80 ° C. overnight. The yield of the polymer after drying was 6.8 g, and the activity per unit zirconium was 5440 g.
-Polymer / milligram atom-Zr. The polymer had an MFR of 0.09 g / 10 min, a density of 0.937 g / cc, an ethylene content of 97.0 wt% and a crystallinity of 71%.

Comparative Example 2 Using the aluminoxane synthesized in Comparative Example 1, Example 2
Similarly, ethylene and propylene were copolymerized. The polymer yield was 4.7 g and the activity per unit zirconium was
3760 g-polymer / milligram atom-Zr. This polymer has MFR of 0.22g / 10min, density of 0.940g / cc, ethylene content of 97.6wt% and crystallinity of 72%.
It was.

Example 3 The procedure of Example 2 was repeated, except that 20 g / hr of 4-methyl-1-pentene was used instead of propylene in the polymerization of Example 2.

The polymer yield was 5.6 g and the activity per unit zirconium was 4480 g-polymer / milligram atom-Zr.
This polymer has an MFR of 0.43 g / 10 min, a density of 0.931 g / cc, an ethylene content of 95.8 wt% and a crystallinity of 60.
It was in%.

Example 4 500 ml of purified toluene and 500 ml of propylene were charged into an autoclave made of SUS with an internal volume of 2 which had been sufficiently replaced with nitrogen at 15 ° C., and subsequently, aluminoxane synthesized in Example 1 corresponding to 10 mg of aluminum atom equivalent. Was charged with bis (cyclopentadienyl) zirconium dichloride dissolved in toluene corresponding to 0.015 mg of zirconium atom, and polymerization was carried out at 15 ° C. for 3 hours. After stopping the polymerization by adding a small amount of ethanol, unreacted propylene was purged. The polymer was dissolved in toluene. Aqueous hydrochloric acid solution was added to the polymer solution to remove the catalyst residue, which was further washed with water, and then toluene was removed, followed by drying.

104 g of [polypropylene] having an [η] of 0.12 dl / g was obtained, and the activity per unit zirconium was 6900 g-polymer / milligram atom-Zr.

Example 5 The procedure of Example 1 was repeated, except that bis (cyclopentadienyl) zirconium monochloride monohydride was used in place of bis (cyclopentadienyl) zirconium dichloride in the polymerization of Example 1. The polymer yield was 2.7 g and the activity per unit zirconium was 2.2 × 10 ⁴ g-polymer / milligram atom-Zr.

Example 6 In the polymerization of Example 1, bis (cyclopentadienyl) titanium dichloride corresponding to 1.25 × 10 ⁻² mg of titanium atom was used instead of bis (cyclopentadienyl) zirconium dichloride.
The same procedure as in Example 1 was carried out except that the polymerization was carried out at 0 ° C. The polymer yield was 6.1 g and the activity per unit titanium was 500 g-polymer / milligram atom-Ti.

As in Example 7 Example 1, AlCl ₃ · 5H ₂ O1 obtained from AlCl ₃ solution
5.0 g and 30 ml of toluene were charged in a 200 ml flask in which the atmosphere was sufficiently replaced with argon, cooled to 0 ° C., and 100 mmol of trimethylaluminum diluted with 30 ml of toluene was added dropwise. Then 5
The temperature was raised to 0 ° C., and the reaction was continued at that temperature for 8 days. Subsequent operations were performed in the same manner as in Example 1, and aluminoxane 3.
2g was obtained. This aluminoxane had a molecular weight of 2730 and an m value of 45.

[Overlap]

Using the aluminoxane thus obtained, ethylene was polymerized in exactly the same manner as in Example 1, and MFR 0.39 g / 10 m
12.1 g of in-polymer was obtained. The activity per unit zirconium was 9.7 × 10 ⁴ -polymer / milligram atom-Zr.

Example 8 Al ₂ (SO ₄₎ using 3 _· 12H ₂ O8.5g, similarly except that reacted for 4 days at 50 ° C. as in Example 1 KoTsuta. Molecular weight 3010, m value 50
3.1 g of aluminoxane of was obtained.

[Overlap]

Using the aluminoxane thus obtained, ethylene was polymerized in exactly the same manner as in Example 1, and MFR 0.29 g / 1
12.5 g of 0 min polymer was obtained. The activity per unit zirconium was 1.0 × 10 ⁵ g-polymer / milligram atom-Zr.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a preparation process of a catalyst used in the method of the present invention.

Claims (1)

[Claims] 1. A compound having a cyclopentanedienyl group of a transition metal selected from the group consisting of titanium, zirconium, hafnium and vanadium (A), and (B) obtained by reacting trialkylaluminum with water. General formula [I] or general formula [II] (Wherein R represents a hydrocarbon group and m represents an integer greater than 40), and a method of polymerizing olefins in the presence of a catalyst consisting of aluminoxane .