JP2913837B2 - Method for purifying ethylene-α-olefin copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for purifying an ethylene-.alpha.-olefin copolymer. More specifically, the present invention uses a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent, wherein ethylene and an α-olefin having 3 or more carbon atoms, or ethylene and 3 carbon atoms are used. The above α-
The present invention relates to a method for removing a halogenated ester compound and a decomposition product thereof from an ethylene-α-olefin-based copolymer obtained by copolymerizing an olefin and a non-conjugated diene compound.

[0002]

2. Description of the Related Art When an ethylene-α-olefin copolymer is produced using a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent, the catalyst components used, etc. If remaining in the copolymer as the final product, it causes problems such as discoloration of the copolymer, deterioration of weather resistance and deterioration of heat resistance.
Therefore, it is necessary to sufficiently remove the remaining catalyst components and the like from the copolymer obtained by the polymerization reaction. Conventionally, as a method of removing a catalyst component from an ethylene-α-olefin-based copolymer produced using a vanadium-based catalyst,
Add a large amount of water to the polymer solution, mix with a mixer, etc.
After extracting the catalyst into the aqueous phase, the aqueous phase and the organic phase are separated, and a slurry obtained by a method of obtaining a polymer having a reduced catalyst component from the organic phase, or a copolymerization reaction in a solvent in which the polymer is not dissolved In addition, a method of reducing the catalyst residue in a copolymer by adding water or an alcohol thereto is known (for example, Koji Saeki, “Polymer Production Process”, Industrial Research Committee, 1971). However, these methods have several disadvantages. For example, in a method of treating with a large amount of water, it is considered that the catalyst component solubilized in water is extracted into water by contact of the catalyst with water, but when it is expected to more completely remove the catalyst component, etc. In addition, it is necessary to sufficiently mix the polymer solution and water. For this purpose, a large and powerful mixing mixer must be used and the number of rotations must be high, which requires a large amount of equipment and power costs, and is not industrially advantageous. Further, in the method using alcohol or the like, it is necessary to purify and reuse the used alcohol, which complicates the process and increases energy consumption, which is not advantageous. As another method, JP-A-63-275605 discloses a method of washing a copolymer obtained using a titanium-based catalyst with water containing an alkaline compound. JP-6471 discloses a method in which a copolymer obtained using a vanadium-based catalyst is oxidized and then treated with water containing an alkaline compound. By the way, in recent years, an ethylene-α-olefin-based rubbery copolymer has been mixed with a resin such as polypropylene,
Since it has been widely used for automotive parts, packaging materials, and the like, the demands for rubber-like copolymers, such as weather resistance and non-coloring properties, have become more stringent. In order to satisfy the demand, it has been strongly required to further reduce the catalyst component remaining in the rubbery copolymer. Under such circumstances, there is a problem that the halogenated ester compound used as an activator of the polymerization reaction remains in the copolymer in addition to the metal catalyst component. If the halogenated ester compound remains in the copolymer, problems such as deterioration of the quality of the copolymer due to halogen, ie, corrosion of the processing machine, coloring of the copolymer, odor and the like occur. In light of such demands, the prior art described in each of the above publications is still unsatisfactory.

[0003]

In view of the above situation, the present inventors have used a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent to obtain ethylene and carbon atoms. In the case of purifying an ethylene-α-olefin-based copolymer obtained by polymerizing 3 or more α-olefins or ethylene and an α-olefin having 3 or more carbon atoms and a non-conjugated diene compound, a conventional method is used. The present invention has been made as a result of intensive studies for the purpose of providing a method capable of removing a halogenated ester to a level that has not been achieved.

That is, the present invention provides a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent, wherein ethylene and an α-olefin having 3 or more carbon atoms or ethylene and an α-olefin having 3 or more carbon atoms are used. A method for purifying an ethylene-α-olefin-based copolymer obtained by polymerizing the above α-olefin and a non-conjugated diene compound, wherein a polymerization reaction mixture obtained by the polymerization reaction is mixed and stirred as described below. It relates to a method for purifying an ethylene-α-olefin-based copolymer, which comprises a step of mixing and stirring in the presence of an alkaline aqueous solution in which the pH of the aqueous phase after the treatment is 10.0 or more. is there.

The details will be described below. In the present invention, purification is carried out by using a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent, using ethylene and a carbon atom having 3 carbon atoms.
A polymerization reaction mixture containing the above-mentioned α-olefin or an ethylene-α-olefin-based copolymer obtained by polymerizing ethylene with an α-olefin having 3 or more carbon atoms and a non-conjugated diene compound.

[0006] As the hydrocarbon solvent, either a solvent soluble in the copolymer or a solvent that does not dissolve the copolymer can be used. For example, aromatic compounds such as benzene and toluene,
Pentane, hexane, aliphatic hydrocarbon compounds such as heptane, cyclopentane, methylcyclopentane, alicyclic hydrocarbon compounds such as cyclohexane, liquefied propylene, liquefied 1-butene, α-olefins such as 4-methylpentene-1, And mixtures thereof are preferably used.

As the vanadium compound, for example, VC
l ₃ , VCl ₄ , VOCl ₃ , VO (OR) _3-m Cl _m (R is carbon number 1 to 1
0 linear or branched alkyl group, cycloalkyl group or aryl group, 3 ≧ m ≧ 0) and the like, and VO (OCH ₃ )
_{Cl 2, VO (OCH 3)} 2 Cl, VO (OH 3) 3, VO (OC 2 H 5) Cl 2, VO (OC 2
_{H 5) 2 Cl, VO (} OC 2 H 5) 3, VO (OC 3 H 7) Cl 2, VO (OC 3 H 7) 2 Cl,
_{VO (OC 3 H 7) 3} , VO (OisoC 3 H 7) Cl 2, VO (OisoC 3 H 7) 2 Cl, VO
(OisoC ₃ H ₇ ) ₃ , V (OCH ₃ ) ₃ , V (OCH ₂ COOCH ₃ ) _{3 and the} like can be exemplified.

As the organoaluminum compound, for example, AlR'nCl _3-n or AlR'n (OR ') _{3- n} (R' has 1 carbon atom)
To 8 linear or branched alkyl groups, 3 ≧ n ≧ 0), (C ₂ H ₅ ) ₂ AlCl, (C ₄ H ₉ ) ₂ AlCl, (C ₆ H ₁₃ ) ₂ AlCl, (C ₂ H
₅ ) _1.5 AlCl _1.5 , (C ₄ H ₉ ) _1.5 AlCl _1.5 , (C ₆ H ₁₃ ) _1.5 AlC
l _1.5 , C ₂ H ₅ AlCl ₂ , C ₄ H ₉ AlCl ₂ , C ₆ H ₁₃ AlCl _{2 and the} like.

As the halogenated ester compound, for example, a compound represented by the following general formula: (Where R "is an organic group partially or entirely halogen-substituted with 1 to 20 carbon atoms, and R"'is a hydrocarbon group having 1 to 20 carbon atoms), and preferably R " Compounds in which all of the substituents are chloro-substituted, or compounds having a phenyl group and a chloro-substituted alkyl group, more preferably perchlorcrotonate, perchlor-3-butenylate or phenyldichloroacetate. Specifically, ethyl dichloroacetate, methyl trichloroacetate, ethyl trichloroacetate,
Methyl dichlorophenyl acetate, ethyl dichlorophenyl acetate, methyl perchlor crotonate, ethyl perchlor crotonate, propyl perchlor chlorotonate, isopropyl perchlor crotonate, butyl perchlor crotonate, butyl perchlor crotonate, cyclopropyl perchlor crotonate, phenyl Perchlorlorcrotonate, methyl perchlor-3-butenylate, ethyl perchlor-3-butenylate, propyl perchlor-3-butenylate,
Perchlor-3-butyl butenylate and the like can be exemplified.

As the α-olefin having 3 or more carbon atoms,
For example, propylene, 1-butene, 1-pentene, 1
-Hexene, 4-methylpentene-1, 1-octene,
1-decene and the like are exemplified. Examples of the non-conjugated diene compound include dicyclopentadiene, tricyclopentadiene, 5-methyl-2,5-norbornadiene,
-Methylene-2-norbornene, 5-ethylidene-2-
Norbornene, 5-isopropylidene-2-norbornene, 5-isopropenyl-2-norbornene, 5-
(1′-butenyl) -2-norbornene, 5- (2′-
Butenyl) -2-norbornene, 1,4-hexadiene, 1,6-octadiene, 6-methyl-1,5-heptadiene and the like. There are no restrictions on the conditions of the polymerization reaction other than the above. In the present invention, it is also a preferable embodiment to use hydrogen as a molecular weight regulator in addition to the above-mentioned catalyst system. Thus, a polymerization reaction mixture which is subjected to the purification of the present invention is obtained.

The purification method of the present invention comprises a step of mixing and stirring the above-mentioned polymerization reaction mixture in the presence of an alkaline aqueous solution having an aqueous phase pH of 10.0 or more after the following mixing and stirring treatment. A method for purifying an ethylene-α-olefin-based copolymer characterized by comprising: Further, as a more specific and preferable method, a method comprising the following first step and second step can be mentioned. First step: pH of the above-mentioned polymerization reaction mixture and the pH of the aqueous phase separated in the following second step
Mixing and stirring with an aqueous solution containing an alkaline compound in such an amount that the amount becomes 10.0 or more. Second step: a step of separating the mixture obtained in the first step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water. Furthermore, a method comprising the following first to third steps can be mentioned. First step:
The polymerization reaction mixture obtained by the above polymerization reaction is mixed with an alkaline aqueous solution containing an alkaline compound in an amount such that the pH of the aqueous phase generated as a result of the second step below becomes 10.0 or more.
A step of stirring. Second step: a step of treating 1 part by volume of the mixture obtained in the first step with 1/5 to 10 parts by volume of neutral water. Third step: a step of separating the mixture obtained in the second step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water.

Examples of the alkaline compound used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide, concentrated ammonia, ammonium hydroxide and the like. Among them, lithium hydroxide, potassium hydroxide, water Sodium oxide is particularly preferred. The required amount of the alkaline compound used is, after mixing and stirring,
The amount is sufficient to adjust the pH of the aqueous phase separated from the organic phase to 10.0 or more, preferably 11 or more. Insufficient alkaline compounds result in insufficient removal of catalyst components and the like. As a preferred embodiment of the method of adding the alkaline aqueous solution, the pH of the alkaline aqueous solution to be added is set to 12 or more, preferably 13 or more, and 1/1000 to 1 part by volume of the polymerization reaction mixture.
After adding and mixing with 10 to 10 parts by volume of water, 1/5 to 10 parts by volume of water is additionally mixed to separate an oil phase and an aqueous phase.

[0013] The amount of water used for water washing is an amount sufficient to effectively extract water mainly from the ash generated from the catalyst component, and an amount capable of separating the organic phase and the aqueous phase. It is necessary that the amount be 1/5 to 10 parts by volume, more preferably 1/4 to 5 parts by volume, per 1 part by volume of the polymerization mixture. It is desirable that the water used here has as little iron content as possible.
The presence of iron in water induces coloration of the target copolymer. The preferred iron concentration is 0.1 ppm or less.

The method of treating the polymerization reaction mixture with an alkaline aqueous solution and an alkaline aqueous solution containing an oxidizing agent may be any method as long as the catalyst components and the like are efficiently brought into contact with each other and the catalyst components and the like are sufficiently extracted into the aqueous phase. Good.
Specifically, a method using a line mixer and the like can be mentioned. A specific method of the step of separating into an aqueous phase and an organic phase is not particularly limited, and examples thereof include a method using a so-called stationary separation drum. The step of treating the polymerization reaction mixture with these alkaline aqueous solution and the oxidizing agent-containing alkaline aqueous solution and the step of separating the aqueous and organic phases,
Normal temperature 20 ~ 160 ℃, preferably 50 ~ 100 ℃, pressure 0 ~
It can be carried out under the conditions of ²⁰ kg / cm ² G, preferably ^{2 to} 10 kg / cm ² G. In carrying out the process, it is preferable to perform water washing a plurality of times after passing through the above-mentioned treatment step of the polymerization reaction mixture with the alkaline aqueous solution and the alkaline aqueous solution containing the oxidizing agent and the step of separating the aqueous and organic phases. The organic phase containing the target copolymer thus obtained is subjected to a usual post-treatment step. That is, for example, the target ethylene-α-olefin-based copolymer can be obtained by distilling off the hydrocarbon solvent by heating and evaporating and drying.

Next, the operation of the present invention will be described. The features of the present invention have already been described in the relevant places, but the greatest feature in the constitution of the present invention is that the polymerization reaction mixture is mixed with an aqueous alkaline solution and stirred. . The halogenated ester compound is easily decomposed and extracted into an aqueous phase by treatment with an alkaline aqueous solution having a relatively high pH. On the other hand, under a pH of 10.0 or less, or under a neutral or acidic condition, the decomposition reaction of the halogenated ester compound is very slow, and it is impossible to substantially completely decompose and remove it. Furthermore, treatment with alkaline water does not hinder the decomposition and extraction of the vanadium compound and the residue of the organoaluminum catalyst, but rather has an effect of accelerating the decomposition and extraction. Therefore, the purification method of the present invention is very effective as a method for decomposing and removing both the metal catalyst residue and the halogenated ester compound.

[0016]

EXAMPLES The present invention will be described below with reference to examples. Example 1 Vanadium oxytrichloride, ethylaluminum sesquichloride, and BPCC (n-butyl perchlorchlortonate, manufactured by Malincklot, USA)
Using a catalyst consisting of
In this manner, ethylene and propylene were copolymerized to prepare a hexane solution containing an ethylene-propylene copolymer. This ethylene / propylene copolymer (ethylene content 73 wt%) in hexane homogeneous solution (copolymer approximately 8 wt%) was 47 ppm as V ₂ O _{5 in} terms of copolymer and A
l ₂ O ₃ as 560 ppm, Cl 700 ppm, and BPCC about 110 ppm
Was contained. To 1000 ml of the hexane solution of the copolymer, add p
Add 500ml of H13 sodium hydroxide aqueous solution, 60 ℃,
The mixture was mixed and stirred at atmospheric pressure for 5 minutes (10000 revolutions / minute) with a mixer. After standing and separating for about 10 minutes, the pH of the aqueous phase was measured to be 12.6. 50 ml of the separated oil phase was sampled and poured into 50 ml of methanol with stirring to remove the copolymer. The remaining amount of BPCC in the hexane-methanol mixed solution thus obtained was quantified by gas chromatography bluff measurement. (The measurement conditions are as follows.)
After adding 500 ml of pure water to the remaining oil phase, mixing and stirring with a mixer for 5 minutes (10,000 rotations / minute), the oil phase was allowed to stand and separated. Hexane was distilled off from the oil phase under heating to isolate the copolymer. Ash content in the copolymer was measured by fluorescent X-ray analysis. Further, the coloring state of the obtained copolymer was visually evaluated. Further, no odor based on the halogenated ester or the like was felt at all. The results are shown in Table 1. Gas Chromatograph Measurement Conditions Model Hitachi Gas Chromatograph 666-50 Column diameter 3mm × 3m SE-30 Detection FID 200 ° C Temperature rise condition 100 ° C constant (10min) → Heat up to 200 ° C at 20 ° C / min (5min) → 200 ℃ constant (15min) Retention time BPCC: 24.5 minutes Ethyldichlorophenyl acetate: 22 minutes Trichloroacetic acid methyl ester: 7.7 minutes

Examples 2 to 5 and Comparative Examples 1 and 2 The same procedure as in Example 1 was carried out except that the pH of the alkaline water used for mixing and stirring with the halogenated ester compound was changed. The results are shown in Table 1.

Example 6 Alkaline water (HaOH 1.25 mol / l, pH 14 or more) prepared by dissolving 5 g of sodium hydroxide in 100 ml of water was added to 1000 ml of the hexane solution of the copolymer used in Example 1, and the mixture was heated at 60 ° C. The mixture was mixed and stirred at atmospheric pressure for 5 minutes (10000 revolutions / minute) with a mixer. Thereafter, 500 ml of pure water was additionally added, followed by mixing and stirring for another 5 minutes (10,000 rotations / minute). After standing and separating for about 10 minutes, the pH of the aqueous phase was measured to be 13.6. next,
After quantifying the remaining amount of BPCC in the oil phase as in Example 1,
500 ml of neutral pure water was added to the separated oil phase, and the mixture was washed by mixing and stirring with a mixer for 5 minutes (10,000 rotations / minute).
Hexane was distilled off by heating and then subjected to ash measurement by fluorescent X-ray analysis. Further, the coloring state of the obtained copolymer was visually evaluated.

Examples 7 and 8 and Comparative Example 3 The procedure was essentially the same as in Example 6, except that the pH of the aqueous alkali solution was changed. The results are shown in Table 2.

[0020]

[0021]

[0022]

[0023]

As described above, according to the present invention, in the presence of a hydrocarbon solvent, a catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound is used.
Or from an ethylene-α-olefin-based copolymer obtained by polymerizing ethylene with an α-olefin having 3 or more carbon atoms and a diene having a non-conjugated double bond, to a level not attainable by the conventional method. A method for purifying a copolymer capable of removing a halogenated ester and removing a metal catalyst component and the like can be provided.

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hayato Sawa 5-1, Anesaki Beach, Ichihara City, Chiba Prefecture Within Sumitomo Chemical Industries Co., Ltd. (72) Inventor Katsunari Inagaki 5-1, Anesaki Beach, Ichihara City, Chiba Prefecture Sumitomo Chemical Industries, Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) C08F ⁶ /00-6/28

Claims (3)

(57) [Claims] 1. A catalyst system comprising a vanadium compound, an organoaluminum compound and a halogenated ester compound in the presence of a hydrocarbon solvent, wherein ethylene and an α-olefin having 3 or more carbon atoms or ethylene and an α-olefin having 3 or more carbon atoms are used. −
A method for purifying an ethylene-α-olefin-based copolymer obtained by a polymerization reaction of an olefin and a non-conjugated diene compound, wherein a polymerization reaction mixture obtained by the polymerization reaction is mixed with water after the following mixing and stirring treatment. A method for purifying an ethylene-α-olefin-based copolymer, comprising a step of mixing and stirring with an aqueous alkaline solution in an amount such that the pH of the phase becomes 10.0 or more. 2. The purification method according to claim 1, comprising the following first step and second step. First step: The polymerization reaction mixture is mixed with the aqueous phase separated in the second step below.
A step of mixing and stirring with an aqueous solution containing an alkaline compound in such an amount that H becomes 10.0 or more. Second step: a step of separating the mixture obtained in the first step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water. 3. The purification method according to claim 1, comprising the following first step, second step and third step. First step: a step of mixing and stirring the polymerization reaction mixture obtained by the polymerization reaction with an aqueous alkaline solution containing an alkaline compound in an amount such that the pH of an aqueous phase formed as a result of the following second step becomes 10.0 or more. Second step: a step of treating 1 part by volume of the mixture obtained in the first step with 1/5 to 10 parts by volume of neutral water. Third step: a step of separating the mixture obtained in the second step into an aqueous phase and an organic phase, and washing the obtained organic phase with neutral water.