JPH11158225A - Purification of cyclic olefin-based polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately and efficiently remove impurities derived from an organoaluminum compound component from a cyclic olefin-based polymer in the case of using a large amount of the organoaluminum compound as a co- catalyst. SOLUTION: In a purification procedure of a cyclic olefin-based polymer obtained by the polymerization of a cyclic olefin in the presence of a catalyst system comprising a transition metal component and an organoaluminum compound component having an aluminum content in a polymerization solution of 2 g/L or more, to a polymerization solution comprising the cyclic olefin-based polymer, a poor solvent with respect to the polymer which is a compound containing a carbonyl group is added to allow the polymer and the metal component residues to precipitate, followed by extracting the polymer with a good solvent with respect to the polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying a cyclic olefin polymer. More specifically, the present invention relates to a method for purifying a cyclic olefin-based polymer when the concentration of an aluminum element derived from an organoaluminum compound in a polymerization solution is at least a specific amount.

[0002]

2. Description of the Related Art Cyclic olefin polymers have a high glass transition temperature (heat resistance) due to their rigid structure, and are also excellent in chemical resistance, heat aging resistance, etc., and are therefore suitable for optical fields. Expectations for use are growing. Cyclic olefin-based polymers include ring-opened polymers and vinylene-type copolymers with α-olefins. In recent years, the former is a tungsten or molybdenum-based metal complex, and the latter is a metallocene-based catalyst centered on zirconium. Is manufactured by
In all cases, the polymerization activity is low, so that the amount of the organoaluminum compound used as a cocatalyst is relatively large, and it is known that the physical properties of the cyclic olefin polymer are deteriorated mainly due to the catalyst residue derived from the aluminum component. Have been.

[0003] In order to solve the above problems, several purification methods have been proposed. For example, a method of washing with an organic acid or an inorganic acid for the decomposition and solubilization treatment of an aluminum component, and a method of contacting with an adsorbent containing a metal cation such as zeolite to remove a halogen component derived from a catalyst component (Japanese Patent Laid-Open No. No.-92208), a method of contacting an aqueous solution of an alkali or chlorine-free acid with a polymerization solution to remove a catalyst component, or a method of contacting a polymerization solution with a filter aid such as diatomaceous earth at a high temperature to perform filtration (particularly). Kaihei 6-
240511), a method of adding an oxidizing agent or a basic compound and extracting and removing impurities with a poor solvent (JP-A-7-109310), and the like.
In addition to the problem that high temperature or heat filtration is required, the purification process is long, and the need to add a large amount of an adsorbent, etc., purification is not sufficient when the organoaluminum component is used in large amounts. I couldn't say.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic aluminum compound component which is preferably and efficiently used without adding a third component, when an organoaluminum compound is used in a large amount as a cocatalyst. It is to remove the derived impurities from the cyclic olefin polymer.

[0005]

According to the present invention, a cyclic olefin is polymerized in the presence of a catalyst system containing a transition metal component and an organoaluminum compound component having a concentration of aluminum element in a polymerization solution of 2 g / liter or more. In the method for purifying the obtained cyclic olefin polymer, a compound having a carbonyl group, which is a poor solvent for the polymer, is added to a polymerization solution containing the cyclic olefin polymer to precipitate the polymer and metal component residue. And then extracting the polymer with a good solvent for the polymer, the method comprising purifying a cyclic olefin polymer.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The cyclic olefin polymer used in the present invention may be a homopolymer of a cyclic olefin, or a cyclic olefin and a compound having 2 carbon atoms.
To 20 α-olefins. Examples of the cyclic olefin include cyclobutene, cyclopentene, cycloheptene, cyclooctene, 2-norbornene, dimethanooctahydronaphthalene and those having 1 to 1 carbon atoms.
Up to 10 alkyl groups, alkenyl groups, aryl groups, substituents of aralkyl groups, or those in which each of the hydrocarbon groups is substituted with a nitrogen atom, an oxygen atom, a silicon atom, a sulfur atom, and as an α-olefin Is ethylene, propylene, 1-butene, 3-methyl-1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene,
-Octene and the like. The polymerization may be ring-opening polymerization or vinylene polymerization.

[0007] The transition metal component used in the present invention is a compound containing a metal element belonging to Groups 4 to 10 of the periodic table, for example, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, nickel, palladium and an organic ligand. Specifically, cyclopentadienyl titanium trichloride, biscyclopentadienyl titanium dichloride, cyclopentadienyl zirconium trichloride,
Biscyclopentadienyl zirconium dichloride, dimethylsilylbis (indenyl) zirconium dichloride, isopropylenecyclopentadienyl (9-fluorenyl) zirconium dichloride, trichlorooxyvanadium, chloro (diethoxy) oxyvanadium, molybdenum hexachloride, tungsten hexachloride, Nickel bisacetylacetonate, palladium bisacetylacetonate and the like can be mentioned. The amount of the transition metal component used is arbitrary within a suitable range. For example, in the case of a solution polymerization system, the amount of the transition metal component used is 1
0 ^-7 to 10 ² mmol / l, preferably from 10 ^-4 to
10 mmol / l. Examples of the organoaluminum compound include trimethylaluminum, alkylaluminums such as triisobutylaluminum, dimethylchloroaluminum, isobutyldichloroaluminum, halogen-containing organoaluminum compounds such as ethylaluminum sesquichloride, and organoaluminum oxy compounds such as polymethylalumoxane. Can be

The compound having a carbonyl group used as a poor solvent in the present invention includes, for example, acetone, 2
-C3-6 monoketones such as butanone and 3-pentanone, diketones such as 2,4-pentanedione, and C2 carbon atoms such as methyl acetate, ethyl acetate and ethyl propionate.
Carboxylic esters, carbonates, amides, aldehydes and the like comprising a carboxylic acid having 1 to 4 carbon atoms and an alcohol having 1 to 4 carbon atoms are exemplified, and monoketones, diketones, and carboxylic esters are particularly preferable. Examples of good solvents include aromatic hydrocarbons such as toluene, xylene and tetralin, halogen-substituted aromatic compounds such as chlorobenzene, 1,2-dichlorobenzene and 1,2,4-trichlorobenzene, and oils such as cyclohexane and decalin. And cyclic hydrocarbons.

According to the present invention, a sufficient effect can be obtained when an organoaluminum compound having an aluminum element content of 2 g / liter or more in the polymerization solution is used. In this case, a decomposition product of the organoaluminum compound generated by the reaction with the carbonyl compound is obtained as a hard solid, and does not adversely affect the subsequent extraction step. The preferred amount of the aluminum element in the polymerization solution is 3 g / liter or more. However, when the amount of the aluminum element is less than 2 g / liter, a gel-like substance is generated by the reaction between the carbonyl compound and the organic aluminum compound, and this gel-like substance floats in a good solvent in a subsequent extraction step, and is filtered. And makes filtration difficult.

In the method for purifying a cyclic olefin polymer according to the present invention, the polymerization solution containing the polymerized cyclic olefin polymer is charged into a poor solvent of 1 to 10 times (volume ratio) and the polymer and metal are added. A component residue precipitates. The poor solvent for the polymer is a compound having a carbonyl group and must be compatible with the polymerization solvent. Since carbonyl compounds such as ketones and esters have relatively weak interaction with the organoaluminum compound, even when used as a poor solvent, the reaction with the organoaluminum compound is mild and can suppress rapid aggregation of the organoaluminum compound. This facilitates separation of the polymer and the organoaluminum compound and separation of the filtrate and the solid component. On the other hand, when an alcohol such as methanol is used, it reacts violently with the organoaluminum compound and abrupt aggregation occurs, so that the polymer is taken into the polymer and purification of the polymer becomes difficult. Separation of the filtrate from the solid also becomes difficult. Further, when a poor solvent that is incompatible with the polymerization solvent is used, the polymer does not precipitate and is merely separated into two layers.

The polymerization solution may be kept heated or cooled, but depending on the polymer, the viscosity of the solution may increase due to cooling, and a uniform powder may not be obtained.
The polymerization solution is preferably introduced into the poor solvent at 20 to 80 ° C. The cyclic olefin-based polymer containing the precipitated metal component residue is filtered and separated from the liquid layer. The obtained polymer powder may be used as it is in the next extraction step, or may be dried. As a drying method, any method can be used as long as it removes volatile components, such as drying under reduced pressure, drying under heating, blowing inert gas, or a combination thereof, but drying under reduced pressure and blowing inert gas under heating are preferable. Drying temperature is 0 to 120 ° C, preferably 20 to 100 ° C.
° C, particularly preferably 40 to 90 ° C. The drying time is not particularly limited, but is preferably 10 hours or less.

The cyclic olefin polymer containing the dried metal component residue is dissolved in a good solvent for the polymer,
Is extracted. The amount of the good solvent used is 1 to 100 ml, preferably 5 to 50 ml, more preferably 10 to 30 ml per 1 g of the dry polymer. At the time of dissolution, heating and stirring may be performed, or pulverization and dissolution may be performed by irradiation with an ultrasonic machine or the like, but heating is preferably performed at a temperature not higher than the boiling point of a good solvent. Upon dissolution of the polymer, the solution becomes a suspended suspension of metal residue.

The above suspension is preferably kept at a temperature not higher than the boiling point of the good solvent for a further 5 minutes to 3 hours, preferably 10 minutes to 2 hours.
The mixture is heated for a period of time to completely dissolve the cyclic olefin polymer, and then filtered. The filtrate is added to a poor solvent of 1 to 10 times (volume ratio) to obtain a purified cyclic olefin polymer. The poor solvent for the polymer used at this time may be generally used methanol, ethanol, acetone or the like.

[0014]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples unless it exceeds the gist. In Examples and Comparative Examples, the amount of residual aluminum in the purified cyclic olefin-based polymer was determined by carbonizing the polymer, melting it with alkali, and then subjecting the polymer to acid dissolution treatment. SPS120 manufactured by Corporation
0).

<Synthesis Example 1> One liter of a dried autoclave was sufficiently purged with nitrogen. This is degassed and dried 2
-50 g of norbornene and 310 ml of toluene are added, and 9
The temperature was raised to 0 ° C. 52 ml of a toluene solution of methylalumoxane (4.4 g as methylalumoxane, 2.0 g as aluminum element) was added and stirred for 15 minutes, and then 40 ml of a toluene solution of cyclopentadienylzirconium trichloride (cyclopentadiene). 65.7 mg of enyl zirconium trichloride) was added,
Polymerization was performed at a nitrogen pressure of 0.2 kg / cm ² G for 3 hours (polymerization solution amount: 450 ml). After the reaction, the temperature was lowered to room temperature, and the polymerization solution was extracted.

Example 1 Approximately 450 polymerization solution of Synthesis Example 1
and pour it into 1 liter of acetone with stirring.
Stir for 5 minutes. After stirring, the mixture was allowed to stand to precipitate a precipitate, which was filtered by suction. The obtained precipitate was dried under reduced pressure at 80 ° C. and 1 mmHg for 3 hours. The yield was 56.4 g, and the precipitate after drying was slightly yellow. Next, 1 liter of toluene was placed in a 2-liter separable flask, and the entire amount of the precipitate was added to form a suspension. The suspension was heated to 80 ° C. and extracted with stirring for 1 hour. After cooling, solid components were removed by suction filtration. The solids turned yellow, but the filtered solution was clear and colorless. The solution was poured into 2 liters of methanol with stirring, the polymer was separated by suction filtration, and dried at 100 ° C. for 12 hours under a nitrogen stream.
The yield was 40.4 g. The yellowed solid was re-added with 1 liter of toluene, and the same operation was carried out. As a result, 1.1 g of a polymer was obtained. However, the same operation was repeated, but no polymer was obtained. Table 1 shows the analysis results of the obtained polymer. <Example 2> The procedure of Example 1 was repeated except that ethyl acetate was used instead of acetone.
Table 1 shows the results.

<Comparative Example 1> The polymerization solution obtained in Synthesis Example 1 was poured into 1 liter of hydrochloric acid-acidic methanol with stirring, stirred for 15 minutes, and allowed to stand still, followed by suction filtration. The separated solid was repeatedly washed with methanol until the washing liquid became neutral, and dried at 100 ° C. for 12 hours under a nitrogen stream. The yield was 44.2 g. Table 1 shows the results. <Comparative Example 2> One liter of toluene was placed in a 1-liter separable flask, and the entire amount of the precipitate obtained in Comparative Example 1 was added and dissolved. 25 g of Celite (Cerite 500, manufactured by Wako Pure Chemical Industries, Ltd.) was suspended therein and stirred at 80 ° C. for 1 hour. After cooling, the celite component was removed by suction filtration, and the filtrate was poured into 2 liters of methanol with stirring, filtered by suction, and dried at 100 ° C. for 12 hours under a nitrogen stream. The yield was 32.7 g. One liter of toluene was added to the filtered celite, and the same operation was performed to collect an unextracted polymer component. The yield was 3.7 g. When the same operation was repeated, 1.3 g of a polymer component was recovered. The total yield of the four extractions was 37.9 g, which still contained unextracted polymer. Table 1 shows the results.

Comparative Example 3 The polymerization solution obtained in Synthesis Example 1 was added to a 2-liter separable flask containing 400 ml of a 5% by weight aqueous sodium hydroxide solution under vigorous stirring, and the mixture was vigorously stirred for 30 minutes. The mixture was allowed to stand and separated to collect the organic phase, which was washed three times with the same volume of water.
The precipitate was filtered by pouring into liters. The precipitate was washed with water and methanol until neutral, and dried at 100 ° C. for 12 hours under a nitrogen stream. The yield was 38.9 g. Table 1 shows the results. <Comparative Example 4> The procedure of Example 1 was repeated, except that methanol was used instead of acetone to precipitate the polymer from the polymerization solution. Although a part of the precipitate was precipitated, most of the precipitate was suspended in the polymerization solution, and it was difficult to perform suction filtration. Table 1 shows the results.

<Synthesis Example 2> One liter of a dried autoclave was flushed with ethylene gas and degassed.
210 ml of dried toluene was charged. After 84 g of 2-norbornene was added thereto and the temperature was raised to 50 ° C., 19.5 ml of a toluene solution of methylalumoxane (1.65 g as methylalumoxane, 0.77 g as aluminum element) was added and stirred for 15 minutes. Thereafter, 4.0 ml of a toluene solution of cyclopentadienyl zirconium trichloride (6.57 mg as cyclopentadienyl zirconium trichloride) was added, and 4.0 ml of ethylene was added.
The polymerization was carried out for 2 hours by applying pressure to kg / cm ² G (polymerization solution amount: 350 ml). After the polymerization was stopped by adding 20 ml of methanol, the temperature was lowered to room temperature, and the polymerization solution was extracted. <Example 3> The same operation as in Example 1 was performed on the polymerization solution obtained in Synthesis Example 2 to obtain a total of 30.3 g of ethylene-
A norbornene copolymer was obtained. Table 1 shows the results. <Comparative Example 5> The same operation as in Comparative Example 1 was performed on the polymerization solution obtained in Synthesis Example 2. Table 1 shows the results.

<Synthesis Example 3> One liter of the dried autoclave was sufficiently purged with nitrogen. This is degassed and dried 2
-50 g of norbornene and 380 ml of toluene are added, and 9
The temperature was raised to 0 ° C. 17 ml of a toluene solution of methylalumoxane (1.69 g as methylalumoxane,
After adding 0.65 g of aluminum element) and stirring for 15 minutes, 4.0 ml of a toluene solution of cyclopentadienyl zirconium trichloride (6.57 mg as cyclopentadienyl zirconium trichloride) was added, and 0.5 ml of nitrogen was added. Polymerization was carried out for 3 hours by applying a pressure of ² kg / cm ² G (polymerization solution amount: 450 ml). After the reaction, the temperature was lowered to room temperature, and the polymerization solution was extracted. <Comparative Example 6> The same operation as in Example 1 was performed on the polymerization solution obtained in Synthesis Example 3. However, when toluene was added to the dried precipitate and the mixture was extracted by heating and then filtered, the eyes of the filter were clogged, that is, filtration took 5.5 hours. After that, reprecipitation was performed and dried to obtain 27.9 g of a solid content. Table 1 shows the results.

[0021]

[Table 1]

[0022]

According to the purification method of the present invention, a cyclic olefin-based polymer component can be preferably and efficiently extracted from a polymerization solution containing a large amount of organoaluminum.

Claims (2)

[Claims] 1. A cyclic olefin polymer obtained by polymerizing a cyclic olefin in the presence of a catalyst system containing a transition metal component and an organic aluminum compound component having a concentration of an aluminum element in a polymerization solution of 2 g / liter or more. In the purification method, after adding a compound having a carbonyl group, which is a poor solvent for the polymer to the polymerization solution containing the cyclic olefin polymer, to precipitate the polymer and metal component residue, A method for purifying a cyclic olefin polymer, comprising extracting the polymer with a good solvent. 2. The method for purifying a cyclic olefin polymer according to claim 1, wherein the organoaluminum compound is an organic alumoxane, and the carbonyl group-containing poor solvent is used in an amount of 1 to 10 times the volume of the polymerization solution.