JP2927887B2 - Method for producing syndiotactic polyolefin polymerization catalyst - Google Patents

Description

The present invention relates to a method for producing a polymerization catalyst for syndiotactic polyolefin. Specifically, the present invention relates to a method for producing a polymerization catalyst for producing a polyolefin having a relatively large particle diameter and a high bulk specific gravity.

(Prior art)

Syndiotactic polypropylene has long been known for its existence, but conventional methods of low-temperature polymerization with a catalyst consisting of a vanadium compound, ether and organoaluminum have poor syndiotacticity, which is characteristic of syndiotactic polypropylene. It was hard to say. On the other hand, JAEWEN et al. Discovered for the first time that a catalyst consisting of a transition metal compound having an asymmetric ligand and an aluminoxane could obtain polypropylene with good tacticity such that the syndiotactic pentad fraction exceeded 0.7. (J.Am.Che
m. Soc., 1988, 110, 6255-6256). According to the present inventors, it has been found that when another α-olefin is polymerized in the same manner, a syndiotactic polyα-olefin can be obtained.

[Problems to be solved by the invention]

The above-mentioned method by JAEWEN et al. Has a good activity per transition metal, and is an excellent method with high tacticity of the obtained polymer.However, the particle size of the obtained polymer is small and the bulk specific gravity is small. There was a problem that the productivity was poor such that the properties were poor and could not be removed by the heat of polymerization. On the other hand, Japanese Patent Application Laid-Open No. 63-198691 discloses a method for producing a polyolefin having a relatively large bulk specific gravity by using a method in which a poor solvent for an aluminoxane or an aluminoxane and a transition metal compound is dissolved and a poor solvent for these compounds is added to the resulting solution. No. 63-248803, the bulk specific gravity is not yet large enough, the particle size of the polymer obtained is small, and the above problem has not been solved.

[Means for solving the problem]

Means for Solving the ProblemsThe present inventors have solved the above-mentioned problems and have studied diligently on a method for producing a poly-α-olefin having high syndiotacticity with high activity, relatively large particle size and high bulk specific gravity with high productivity, and have developed the present invention. completed.

That is, the present invention relates to an aluminoxane or an aluminoxane having the general formula: (Where A and B are different aromatic hydrocarbons, R is A,
X is a halogen atom or a hydrocarbon residue having 1 to 20 carbon atoms, and M is a metal atom selected from titanium, zirconium and hafnium. A method for producing a polymerization catalyst in which a poor solvent for a transition metal compound having an asymmetric ligand represented by formula (1) is dissolved in a solvent in which the compound is dissolved to form a polymerization catalyst (the transition metal compound having the asymmetric ligand is When not used, further treating with a transition metal compound having an asymmetric ligand), wherein a polymer compound dissolved in a solvent and precipitated in a poor solvent is previously dissolved. This is a method for producing a tic polyolefin polymerization catalyst.

Examples of the transition metal compound used in the present invention include the compounds described in the above-mentioned documents. (Where A and B are different aromatic hydrocarbons, R is a hydrocarbon residue having 1 to 20 carbon atoms connecting A and B, or a compound containing silicon, and X is a halogen atom or a 1 to 20 carbon atom. A hydrocarbon residue, wherein M is a metal atom selected from titanium, zirconium and hafnium.) As A and B, monocyclic or polycyclic aromatic compounds having 5 to 30 carbon atoms can be exemplified. Specifically, cyclopentadienyl or a part or all of hydrogen thereof has 1 carbon atom.
Polycyclic aromatic compounds such as indenyl, fluorenyl, etc., or a part of hydrogen, substituted with an alkyl group of 10 to 10 (here, the alkyl group may have a structure in which the terminal is again bonded to a cyclopentadiene ring). Or those in which all are substituted with an alkyl group having 1 to 10 carbon atoms. As R, a dialkyl methylene group, dialkylsilylene group is preferred, for example, R _'2 C, R' ₂ Si (wherein R 'may be the same or different alkyl radical of hydrogen or carbon number of 1 to 20.) Can be preferably used, and an ethylene group represented by -CR'-CR'- can also be exemplified (wherein R 'is the same as described above). X can be exemplified by fluorine, chlorine, bromine, iodine, or an aromatic compound such as an alkyl group such as methyl, ethyl, propyl, or butyl, or a cyclopentadienyl group. Particularly, a chlorine or methyl group is preferable. The aluminoxane has a general formula: (Wherein R is a hydrocarbon residue having 1 to 3 carbon atoms). Examples thereof include methylaluminoxane wherein R is a methyl group and n is 5 or more. The use ratio of the aluminoxane to the transition metal compound is 1 to 1,000,000 mole times, usually 10 to 5000 mole times.

What is important in the present invention is to dissolve the solvent in a solvent in which the aluminoxane or the transition metal compound having an asymmetric ligand with the aluminoxane is dissolved, and dissolve in advance the polymer compound precipitated with the poor solvent. is there.

Here, as the polymer compound, polystyrene, poly α
Aluminoxane such as methylstyrene, polymethylstyrene, polychlorostyrene, polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, polycyclohexylethylene, polycyclopentadiene, polydicyclopentadiene, and a transition metal compound having an asymmetric ligand; Various polymer compounds that do not react with each other can be preferably used.

As the poor solvent used here, an aliphatic hydrocarbon compound such as pentane or hexane is usually used. This is achieved by adding these poor solvents to precipitate aluminoxane or an aluminoxane and a transition metal compound simultaneously with the polymer compound. There is no particular limitation on the method of precipitation by adding a poor solvent, but it can be controlled so as to obtain a desired catalyst particle size by conditions such as good dripping of the poor solvent, dripping time, temperature at the time of dripping or stirring speed. . The temperature at the time of the precipitation is not particularly limited, but is usually at −20 to 100 ° C.

The amount of the polymer compound to be added may be an amount necessary for encapsulating the catalyst particles, and the amount may be very small. Usually, the weight ratio of the aluminoxane or the transition metal compound having an asymmetric ligand to the aluminoxane is in the range of equivalent to 1/1000, preferably 1/2 to 1/500. Usually, after the catalyst is deposited, the catalyst is washed with the aliphatic hydrocarbon compound used for the deposition to remove the catalyst which has not been deposited but is merely adsorbed. Here, a catalyst precipitated using only aluminoxane without using a transition metal compound having an asymmetric ligand is used for polymerization after adding and catalyzing a transition metal compound having an asymmetric ligand. . The method of adding and contacting with the transition metal compound having this asymmetric ligand is not particularly limited, and a method of adding a transition metal compound having an asymmetric ligand dissolved in a solvent to a precipitated catalyst is usually used. Can be

In the polymerization, the above catalyst is usually used alone, but it may be used in combination with an aluminoxane or an organic aluminum compound such as a trialkylaluminum in which an alkyl residue having 1 to 12 carbon atoms is bonded by 2 to 3 or a dialkylaluminum halide. It is possible.

In the present invention, the α-olefin is propylene,
Butene-1, pentene-1, hexene-1, heptene-
1, octene-1, nonene-1, decene-1, undecene-1, dodecene-1, tridecene-1, tetradecene-1, pentadecene-1, hexadecene-1, octadecene-1, and other linear α-olefins. Examples thereof include branched α-olefins such as 3-methylbutene-1, 4-methylpentene-1, and 4,4-dimethylpentene-1. These α-olefins may be used alone or in a mixture with each other or in a small amount of ethylene. Are also shown.

The polymerization conditions are not particularly limited, and a solvent polymerization method using an inert medium, a bulk polymerization method substantially free of an inert medium, and a gas phase polymerization method can be used. The polymerization temperature is -100 to 200 ° C, and the polymerization pressure is normal pressure to 100 kg / cm.
It is common to do in ² . Preferably, it is -100 to 100 ° C and normal pressure to 50 kg / cm ² .

〔Example〕

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

Example 1 80 mg of isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride obtained by lithiating isopropylcyclopentadienyl-1-fluorene synthesized according to a conventional method and reacting with zirconium tetrachloride was added to Tosoh Akzo. 17 g of methylaluminoxane (degree of polymerization 16.2) manufactured by Co., Ltd. is dissolved in 100 ml of toluene and 500 ml
, And a solution of 200 mg of polyethylene (GP-PS) manufactured by Mitsui Toatsu Chemicals, Inc. in 5 ml of toluene was added with stirring to obtain a purple homogeneous solution. Then 150 ml of pentane were added with stirring. After further stirring at room temperature for 30 minutes, the mixture was filtered under a nitrogen stream to remove excess isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride and methylaluminoxane.
Subsequently, the precipitated catalyst was washed and filtered twice with 100 ml of pentane to obtain a catalyst. Analysis showed that the catalyst contained 0.08 wt% zirconium.

0.15 g of the catalyst thus obtained was placed in an autoclave having an inner volume of 5 sufficiently purged with nitrogen, 1.5 kg of propylene was added, polymerization was carried out at 60 ° C. for 2 hours, unreacted propylene was purged, the polymer was taken out, dried and weighed. This gave 148 g of polymer (corresponding to 1230 kg of polypropylene / g of zirconium). The bulk specific gravity of this polymer is 0.40 g /
ml, and the average particle size was 420 μm. Also ¹³ C-NMR
According to the syndiotactic pentad fraction is 0.82, intrinsic viscosity measured at 135 ℃ tetralin solution (hereinafter, referred to as
η) is the ratio between the weight average molecular weight and the number average molecular weight measured with 0.79, 1,2,4-trichlorobenzene (hereinafter referred to as MW / M).
N) was 2.2.

Comparative Example 1 156 g of syndiotactic polypropylene was obtained in the same manner as in Example 1 except that polystyrene was not used in the synthesis of the catalyst (this corresponds to 1300 kg of polypropylene / 1 g of zirconium). The bulk specific gravity of this polymer was 0.20 g / ml, it contained a large amount of fine powder having a particle size of 50 μm or less, and the particle size distribution was wide. The syndiotactic pentad fraction by ¹³ C-NMR is 0.82, η is 0.81, MW
/ MN was 2.3.

Example 2 A catalyst was synthesized in the same manner as in Example 1 except that 100 ml of n-decane was added as a poor solvent in place of pentane, and the mixture was stirred at room temperature for 30 minutes and then reduced in pressure at 35 ° C. to remove toluene. Analysis showed that the catalyst contained 0.09 wt% zirconium.

Polymerization was carried out in the same manner as in Example 1 except that 0.16 g of the catalyst thus obtained was used. Unreacted propylene was purged, the polymer was taken out, dried and weighed to obtain 72 g of a polymer. Polymer bulk specific gravity 0.34g / ml, average particle size 380μ
m, ¹³ C-NMR, the syndioctatic pentad fraction was 0.81, η was 0.80, and MW / MN was 2.3.

Example 3 A solution obtained by dissolving 200 mg of polystyrene (GP-PS) manufactured by Mitsui Toatsu Chemicals, Inc. in 5 ml of toluene was added to 100 ml of a 20 wt% toluene solution of methylaluminoxane (polymerization degree: 16.2) manufactured by Tosoh Akzo Co., Ltd. While adding a homogeneous solution.
Then, 100 ml of n-decane was added, and the mixture was stirred at room temperature for 30 minutes, and the pressure was reduced at 35 ° C. to remove toluene. Then, the mixture was filtered under a nitrogen stream to remove excess methylaluminoxane. Next, the precipitated catalyst was washed and filtered with 100 ml of pentane for two times.
This was repeated twice to obtain a catalyst. 4.0 g of this catalyst was suspended in 300 ml of hexane, and 30 mg of isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride was suspended.
Was dissolved in 20 ml of toluene to obtain a catalyst slurry. Analysis showed that this catalyst contained 0.15 wt% zirconium.
Contained.

Polymerization was carried out in the same manner as in Example 1 except that 0.15 g of the catalyst slurry thus obtained was used as a catalyst. Unreacted propylene was purged, the polymer was taken out, dried and weighed.
158 g of polymer were obtained (this is 702 kg polypropylene /
This corresponds to 1 g of zirconium. ). The bulk specific gravity of this polymer was 0.39 g / ml, and the average particle size was 400 μm. Also
^The syndiotactic pentad fraction by ¹³ C-NMR is 0.
80, η was 0.79, and MW / MN was 2.3.

Comparative Example 2 The procedure of Example 3 was repeated, except that the catalyst was synthesized without using polystyrene, to obtain 115 g of a polymer. The η of the polymer was 0.81, the bulk specific gravity was 0.19 g / ml, and the syndiotactic pentad fraction by ¹³ C-NMR was 0.80.

Example 4 20 mg% of isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride 100 mg and methylaluminoxane (polymerization degree 16.2) manufactured by Tosoh Akzo Co., Ltd.
To 100 ml of toluene solution, 300 mg of poly-α-methylstyrene was added.
A solution dissolved in 10 ml of toluene was added with stirring to obtain a homogeneous solution. Then, 100 ml of n-decane was added, and the mixture was added at room temperature for 3 hours.
After stirring for 0 minutes, the pressure was reduced at 35 ° C. to remove toluene. Then, the mixture was filtered under a nitrogen stream to remove excess isopropyl (cyclopentadienyl-1-fluorenyl) zirconium dichloride and methylaluminoxane, thereby obtaining a deposition catalyst. Next, the catalyst was washed and filtered twice with 100 ml of pentane to obtain a catalyst. Analysis showed that this catalyst contained 0.12 wt% zirconium.

Polymerization was carried out in the same manner as in Example 1 except that 0.15 g of the catalyst thus obtained was used. Unreacted propylene was purged, and the polymer was taken out and weighed to obtain 108 g of a polymer (600 kg of polypropylene / zirconium). 1 g). The bulk specific gravity of this polymer was 0.35 g / ml, and the average particle size was 400 μm. The syndiotactic pentad fraction by ¹³ C-NMR is 0.81, η is 0.80,
MW / MN was 2.2.

〔The invention's effect〕

By carrying out the method of the present invention, a syndiotactic polyolefin having a large bulk specific gravity can be obtained, which is extremely valuable industrially.

[Brief description of the drawings]

 FIG. 1 is a flowchart for helping the understanding of the present invention.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-63-152608 (JP, A) WO 88/5058 (WO, A1) Journal of the American Chemical Society, Vol. 18, p. 6255-6256 (1988) (58) Fields investigated (Int. Cl. ⁶ , DB name) C08F 10/00-10/14 C08F 110/00-110/14 C08F 210/00-210/18 C08F 4/00-4/82

Claims (1)

(57) [Claims] An aluminoxane or an aluminoxane and a general formula: (Where A and B are different aromatic hydrocarbons, R is A,
X is a halogen atom or a hydrocarbon residue having 1 to 20 carbon atoms, and M is a metal atom selected from titanium, zirconium, and hafnium. A method for producing a polymerization catalyst in which a poor solvent for a transition metal compound having an asymmetric ligand represented by formula (1) is dissolved in a solvent in which the compound is dissolved to form a polymerization catalyst (the transition metal compound having the asymmetric ligand is When not used, further treating with a transition metal compound having an asymmetric ligand), wherein a polymer compound dissolved in a solvent and precipitated in a poor solvent is previously dissolved. A method for producing a tic polyolefin polymerization catalyst.