JP3111435B2 - Method for deashing elastomeric olefin copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention demineralizes an elastomeric olefin copolymer such as ethylene-propylene rubber or ethylene-propylene-diene terpolymer obtained by suspension polymerization in liquid propylene. About the method.

[0002]

2. Description of the Related Art Ethylene propylene rubber and ethylene propylene
Elastomer-like olefin copolymers such as propylene / diene terpolymers are generally prepared by using a transition metal compound such as a trivalent or pentavalent vanadium compound and an organoaluminum compound as catalysts to prepare ethylene and propylene or ethylene. And propylene and a non-conjugated diene-based hydrocarbon. As industrial processes, a suspension polymerization method in which polymerization is performed in liquid propylene and a solution polymerization method in which polymerization is performed in an organic solvent such as n-hexane have been mainly performed.

[0003] The solution polymerization method has an advantage that almost no blockage occurs in the reactor because the olefin copolymer produced during the polymerization hardly precipitates. In addition, since the polymerization pressure is low, the design, manufacture and operation of the reactor are easy, and the transfer of the solution after the polymerization is easy. Furthermore, since the deashing operation is extremely easy, an olefin copolymer having an extremely low content of the catalyst residue (about 5 ppm) can be easily obtained. For this reason, conventionally,
The solution polymerization method was mainly performed.

However, in the solution polymerization method, since the viscosity of the polymerization solution sharply increases as the polymerization proceeds, the concentration of the olefin polymer is limited to about 7 to 10%.
The molecular weight could not be increased. Also, it was difficult to remove the heat of polymerization. Further, there is a problem that a deashing step, a coagulation step, a solvent recovery step and the like are required, and the process becomes complicated. For this reason, in recent years, it has been studied to adopt a suspension polymerization method that does not have such a disadvantage.

[0005]

[Problem to be Solved] In the suspension polymerization method, the polymerization proceeds in a state of a slurry liquid in which an olefin-based copolymer is suspended in a liquid state in liquid propylene, so that the polymerization system does not have high viscosity. . Therefore, there is a possibility that the concentration and molecular weight of the olefin-based copolymer can be increased as compared with the solution method. Also, the removal of heat of polymerization is extremely easy due to the latent heat of vaporization of propylene. Further, it is easy to control the monomer composition ratio in the olefin copolymer.

However, in this polymerization method, since the copolymer is formed so as to enclose the catalyst, it is difficult to remove the catalyst by demineralization after polymerization. However, when the vanadium content in the olefin-based copolymer is high, the olefin-based copolymer may be colored yellow or brown or its physical properties may be reduced. For this reason, it is strongly required that the vanadium content be low, and in particular, in recent years, an extremely low content of 5 ppm or less has been demanded.

[0008] In order to solve the above-mentioned problems in the suspension polymerization method, an activator such as ethyl monochloromalonate or ethyl dichloromalonate is added to the polymerization system to improve the activity of the catalyst. It has been studied to reduce the vanadium content of the olefin-based copolymer itself. At the same time, improvement of the demineralization process was also considered. First, a deashing method of washing the slurry obtained in the polymerization step with water, an alkaline aqueous solution, a tartaric acid aqueous solution, or alcohol was examined (JP-B-48-16063). In addition, a method of adding an extract such as hydrochloric acid, acetic acid, an aqueous solution of caustic soda, a complexing solution such as tartaric acid or gluconic acid, and an oxidizing agent to a slurry, and then mixing an organic solvent such as toluene with the slurry was studied. (Japanese Patent Publication No. 46-5156). Furthermore, a method of adding polyether diamine or polyether monoamine to the slurry after polymerization and washing with water (Japanese Patent Publication No. 46-6985), adding alcohol to the slurry, and then washing the slurry with water or an aqueous alkali solution. A method and a method of adding water after adding a good solvent and a surfactant (JP-A-60-69112) were also studied.

However, even with these methods, it has been difficult to obtain an olefin copolymer having an extremely low vanadium content of 5 ppm.

It is an object of the present invention to provide a method for demineralizing an olefin copolymer having a very low vanadium content of 5 ppm or less.

[0011]

Technical Solution to Solve the Problems
A method for deashing an elastomeric olefin copolymer obtained by suspension polymerization of ethylene and propylene, or ethylene and propylene and a conjugated diene hydrocarbon, using a vanadium compound and an organoaluminum compound as catalysts, First, an alcohol, an aliphatic hydrocarbon, an alicyclic hydrocarbon and an aromatic hydrocarbon are added to the slurry liquid obtained in the polymerization step.
Mix with a good solvent selected from the group consisting of hydrogen ( however,
The amount of good solvent is calculated by weight ratio to unreacted liquid propylene.
Is in the range of 0.01 to 0.40) , and then water or an alkaline aqueous solution is added, and the catalyst residue in the elastomeric olefin-based copolymer is extracted into the aqueous phase. Hereinafter, the present invention will be described in more detail.

First, the slurry obtained in the polymerization step is
As a first step, an alcohol and a good solvent are added, followed by stirring and mixing. At this stage, the olefin-based copolymer particles in the slurry liquid are swelled by the added good solvent, and the catalyst residue in the particles is decomposed by the alcohol to become a highly water-soluble compound such as an alcoholate. The amount of the alcohol to be added is preferably such that the weight ratio to the produced olefin-based copolymer is in the range of 0.02 to 20, and particularly preferably in the range of 0.5 to 10. . The amount of the good solvent, the weight ratio of liquid propylene unreacted slurry liquid is set to be in the range of 0.01 to 0.40, the range of 0.02 to 0.30 is good or <br/> New When the ratio of the alcohol to the olefin-based copolymer is less than 0.02, the efficiency of extracting the catalyst residue is too low to achieve the object of the present invention. On the other hand, if the alcohol ratio is more than 20, the efficiency of extracting the catalyst residue will no longer be improved, and the added alcohol will simply be wasted. If the amount of the good solvent with respect to the unreacted liquid propylene is less than 0.01, the olefin-based copolymer does not swell sufficiently, and there is a problem that the extraction of the catalyst residue is not sufficiently performed. On the other hand, when it is more than 0.40, there is a problem that the produced olefin-based copolymer dissolves and the viscosity of the slurry increases. The ratio between the alcohol and the good solvent is preferably in the range of 1/10 to 100/1 (volume ratio). If the ratio of alcohol to good solvent is outside this range,
It is not preferable because the extraction efficiency of the catalyst residue is deteriorated. The temperature is preferably in the range of -10 to 60C. The alcohol and the good solvent can be added simultaneously. In this case, the alcohol and the good solvent may be added as a mixed solution, or may be added separately without mixing. Also, the alcohol may be added first, followed by the good solvent, or vice versa.

In the present invention, preferred alcohols are those represented by ROH. Here, R is an alkyl group having 1 to 12 carbon atoms or an arylalkyl group. Specifically, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-
Aliphatic saturated alcohols such as butyl alcohol, isobutyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol, nonyl alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol, alicyclics such as cyclopentanol and cyclohexanol Alcohol, allyl alcohol, aliphatic unsaturated alcohols such as crotyl alcohol,
Aromatic alcohols such as benzyl alcohol and cinnamyl alcohol are used. Most preferred among these are aliphatic saturated alcohols.

A good solvent has a solubility parameter of 7.
What is 3-9.5 is used. If the solubility parameter is within this range , solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons and aromatic hydrocarbons can be used. Such solvents include, for example, n-hexane, n-heptane, n-nonane, n-decane, n-undecane, n-dodecane, cycloheptane, cyclohexane, methylcyclohexane, benzene, xylene, ethylbenzene, > Chile down, and the like. However, a solvent having a solvation parameter smaller than 7.3 is not preferable because a swelling effect of the polymer is small and a solvent larger than 9.5 has a small catalyst removing effect.

As a second step, water or an alkaline aqueous solution is added to a slurry liquid containing an alcohol and a good solvent, and the mixture is stirred to extract a catalytic decomposition product in the olefin copolymer particles into an aqueous phase. The addition amount of water or an aqueous alkali solution is preferably in the range of 0.01 to 10% by weight based on the weight of the olefin copolymer, and the temperature at the time of addition and stirring is -10 to 60 ° C. Is preferable. In order to separate the aqueous phase, for example, a method such as standing is possible.
At this time, the aqueous phase separates downward, and the slurry of the olefin copolymer particles separates upward.

As the alkaline solution usable in the present invention, those having a pH of 4.0 to 12 are used. Examples of such an aqueous solution include an aqueous caustic soda solution, an aqueous caustic potassium solution, and an aqueous ammonia solution. An acidic aqueous solution having a pH of less than 4.0 is not preferable because it easily causes corrosion of the apparatus, and an alkaline aqueous solution having a pH of more than 12 is not preferable because the catalytic decomposition product is hardly dissolved.

[0017]

The present invention will be specifically described below with reference to examples.

[0018]

Example 1 A 2-liter stainless steel autoclave was charged with 500 g of liquid propylene and 5-ethylidene-
11 ml of 2-norbornene, 2.9 mmol of diethylaluminum chloride, and 0.1 mmol of diethylzinc
l was charged. Next, the polymerization temperature was set at 20 ° C.
While stirring the contents, while supplying ethylene at a pressure 2 kg / cm ² and G higher than the internal pressure of the autoclave,
A solution obtained by dissolving 0.047 mmol of vanadium triacetylacetonate in 4 cc of toluene was injected under pressure to start polymerization. The polymerization was performed for 25 minutes. A mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 4: 6 was used as an activator, and a solution obtained by dissolving 0.09 mmol of this mixture in toluene to make 3 ml was completed from the start of polymerization. Added continuously over time. After 25 minutes, 596 g of a slurry liquid was obtained.
The slurry concentration of this slurry liquid was 27.9% by weight. The slurry concentration is It was calculated by the following formula. First, a mixed solution of methyl alcohol and toluene (volume ratio 7: 3) 7
0 ml was added and stirred vigorously at 20 ° C. for 10 minutes. Then, 430 ml of a sodium hydroxide aqueous solution having a pH of 10 was added,
The mixture was stirred for 20 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 69.5% by weight, a propylene content of 25.8% by weight, and a 5-ethylidene-2-norbornene content of 4.7% by weight. The number average molecular weight Mn is 309,000 and the weight average molecular weight Mw is 77
2,000 and Mw / Mn = 2.5. Vanadium content is 2.8 ppm, aluminum content is 2
It was 26 ppm. The copolymer in the slurry before the decalcification had a vanadium content of 18.5 ppm and an aluminum content of 602 ppm.

[0019]

Example 2 A 2-liter stainless steel autoclave was charged with 500 g of liquid propylene and 5-ethylidene-
10 ml of 2-norbornene, 2.9 mmol of diethylaluminum chloride, and 0.1 mmol of diethylzinc
l was charged. Then, the polymerization temperature was set at 23 ° C.
While stirring the contents, while supplying ethylene at a pressure 2 kg / cm ² and G higher than the internal pressure of the autoclave,
A solution prepared by dissolving 0.04 mmol of vanadium triacetylacetonate in 5 cc of toluene was injected under pressure to initiate polymerization. The polymerization was performed for 30 minutes. As the activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 2: 8 was used, and a solution obtained by dissolving 0.15 mmol of this mixture in toluene to make 5 ml was completed from the start of polymerization. Added continuously over time. After 30 minutes, 607 g of a slurry liquid was obtained. The slurry concentration in the slurry liquid was 31.4% by weight.
The slurry concentration was calculated in the same manner as in Example 1.
First, 70 ml of a mixed solution of isopropyl alcohol and toluene (volume ratio of 7: 3) was added to the slurry,
Stirred vigorously at 10 ° C. for 10 minutes. Next, 430 ml of an aqueous solution of caustic soda having a pH of 11 was added, and the mixture was stirred for 20 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 69.4% by weight and a propylene content of 26.
The content of 4% by weight and 5-ethylidene-2-norbornene was 4.2% by weight. The number average molecular weight Mn is 295,
000, the weight average molecular weight Mw is 821,000,
Mw / Mn = 2.8. The vanadium content is 2.
The content of aluminum was 5 ppm, and the content of aluminum was 221 ppm. The copolymer in the slurry before the deashing had a vanadium content of 14.6 ppm and an aluminum content of 54.
It was 0 ppm.

[0020]

Example 3 In a stainless steel autoclave having a content of 2 liters, 500 g of liquid propylene and 5-ethylidene-
9 ml of 2-norbornene, 2.9 mmol of diethylaluminum chloride, and 0.1 mmol of diethylzinc
Was charged. Next, the polymerization temperature was set to 25 ° C., and while stirring the contents, ethylene was supplied at a pressure ² kg / cm ² and G higher than the internal pressure of the autoclave,
A solution of 0.043 mmol of vanadium triacetylacetonate dissolved in 4 cc of toluene was injected under pressure to initiate polymerization. The polymerization was performed for 25 minutes. As the activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 1: 9 was used, and a solution obtained by dissolving 0.15 mmol of this mixture in toluene to make 5 ml was completed from the start of polymerization. Added continuously over time. After 25 minutes, 593 g of a slurry liquid was obtained. The slurry concentration in the slurry liquid was 26.7% by weight.
The slurry concentration was calculated in the same manner as in Example 1.
First, 100 ml of a mixture of methyl alcohol and cyclohexane (volume ratio of 7: 3) was added to the slurry,
Vigorously stirred at 5 ° C. for 10 minutes. Then, pH 11.5
Was stirred for 20 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 69.7% by weight and a propylene content of 2
The content of 5.5% by weight and 5-ethylidene-2-norbornene was 4.8% by weight. Number average molecular weight Mn is 36
5,000, the weight average molecular weight Mw was 818,000, and Mw / Mn was 2.2. The vanadium content was 3.3 ppm and the aluminum content was 254 ppm. The copolymer in the slurry before the deashing had a vanadium content of 17.5 ppm and an aluminum content of 6.
It was 26 ppm.

[0021]

Example 4 A 2-liter stainless steel autoclave was charged with 500 g of liquid propylene and 5-ethylidene-
11 ml of 2-norbornene, 2.9 mmol of diethylaluminum chloride, and 0.1 mmol of diethylzinc
l was charged. Then, the polymerization temperature was set at 25 ° C.
While stirring the contents, while supplying ethylene at a pressure 2 kg / cm ² and G higher than the internal pressure of the autoclave,
A solution in which 0.042 mmol of vanadium triacetylacetonate was dissolved in 3 cc of toluene was injected under pressure to initiate polymerization. The polymerization was performed for 25 minutes. As the activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 2: 8 was used. A solution prepared by dissolving 0.14 mmol of this mixture in toluene to make 3 ml was continuously added from the start to the end of the polymerization. After 25 minutes, 599 g of a slurry liquid was obtained. The slurry concentration of this slurry liquid was 28.5% by weight. The slurry concentration was calculated in the same manner as in Example 1. First, a mixture of methyl alcohol and toluene (methanol 100 ml and toluene 4
(5 ml of a mixture) and stirred vigorously at 20 ° C. for 10 minutes. Next, 400 ml of water was added, the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry liquid. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 68.8% by weight and a propylene content of 2%.
The content of 5.7% by weight and the content of 5-ethylidene-2-norbornene was 5.5% by weight. Number average molecular weight Mn is 28
8,800, the weight average molecular weight Mw was 699,000, and Mw / Mn was 2.4. The vanadium content was 3.3 ppm and the aluminum content was 232 ppm. The copolymer in the slurry before the decalcification had a vanadium content of 16.1 ppm and an aluminum content of 5%.
It was 89 ppm.

[0022]

Example 5 A 2-liter stainless steel autoclave was charged with 500 g of liquid propylene and 5-ethylidene-
11 ml of 2-norbornene, 2.9 mmol of diethylaluminum chloride, and 0.3 kg / cm ^{2 of} hydrogen
G was charged. Then, the polymerization temperature was set to 21 ° C.
While stirring the contents, while supplying ethylene at a pressure 2 kg / cm ² and G higher than the internal pressure of the autoclave,
A solution of 0.04 mmol of vanadium triacetylacetonate dissolved in 3 cc of toluene was injected under pressure to initiate polymerization. The polymerization was performed for 30 minutes. As the activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 3: 7 was used. A solution prepared by dissolving 0.14 mmol of this mixture in toluene to make 4 ml was continuously added from the start to the end of the polymerization. After 30 minutes, 600 g of a slurry liquid was obtained. The slurry concentration in the slurry liquid was 29.3% by weight.
The slurry concentration was calculated in the same manner as in Example 1.
First, isopropyl alcohol 10
Mixed solution of 0 ml and toluene 50 ml (volume ratio 7: 3) 7
0 ml was added and stirred vigorously at 21 ° C. for 20 minutes. Next, 350 ml of water was added, the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry liquid. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 67.9% by weight, a propylene content of 26.3% by weight, and a 5-ethylidene-2-norbornene content of 5.
It was 8% by weight. Number average molecular weight Mn is 289,00
0, the weight average molecular weight Mw is 715,000,
/Mn=2.5. The vanadium content is 3.4p
pm, and the aluminum content was 238 ppm.
The copolymer in the slurry before the deashing had a vanadium content of 15.0 ppm and an aluminum content of 576 p.
pm.

[0023]

EXAMPLE 6 In a stainless steel autoclave having a content of 2 liters, 500 g of liquid propylene, 15 ml of dicyclopentadiene and 2.9 of diethylaluminum chloride were placed.
mmol and 0.2 mmol of diethyl zinc. Then, the polymerization temperature was set to 25 ° C., and while stirring the contents, ethylene was added to the autoclave at an internal pressure of 2 ° C.
kg / cm ² , G
A solution of 3 mmol of vanadium triacetylacetonate dissolved in 3 cc of toluene was injected under pressure to initiate polymerization.
The polymerization was carried out for 40 minutes. As the activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 3: 7 was used. 0.15 of this mixture
A solution obtained by dissolving mmol in toluene to make 5 ml was continuously added from the start to the end of the polymerization. The amount of the obtained slurry liquid was 584 g. The slurry concentration in the slurry liquid was 27.2% by weight. The slurry concentration was calculated in the same manner as in Example 1. First, a mixed solution of 255 ml of methyl alcohol and 45 ml of cyclohexane was added to the slurry, and the mixture was vigorously stirred at 25 ° C. for 15 minutes. Next, 200 ml of water was added, the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry liquid. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 59.3% by weight, a propylene content of 32.5% by weight, and a dicyclopentadiene content of 8.2% by weight. Number average molecular weight Mn is 344,0
00, the weight average molecular weight Mw is 965,000,
w / Mn = 2.8. Vanadium content is 4.5
ppm and aluminum content were 249 ppm.
The copolymer in the slurry before the deashing had a vanadium content of 19.6 ppm and an aluminum content of 626 p.
pm.

[0024]

Comparative Example 1 In the same manner as in Example 1, a slurry liquid having a slurry concentration of 27.4% by weight, in which an olefin copolymer was suspended in liquid propylene, was obtained. This slurry liquid 5
To 95 g, 430 ml of an aqueous solution of sodium hydroxide at pH 10 was added in the first stage, and the mixture was vigorously stirred and mixed at 20 ° C. for 10 minutes. Next, in a second step, 70 ml of a mixture of methyl alcohol and toluene (volume ratio 7: 3) was added, and the mixture was stirred for 20 minutes. Thereafter, the mixture was allowed to stand for 30 minutes, and the aqueous phase was separated. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 69.8% by weight and a propylene content of 25.5.
% By weight, and the content of 5-ethylidene-2-norbornene was 4.7% by weight. Number average molecular weight Mn is 312,0
00, the weight average molecular weight Mw is 783,000,
w / Mn = 2.5. Vanadium content is 8.6
ppm was high. Aluminum content is 260ppm
Met. The copolymer in the slurry before the deashing had a vanadium content of 18.7 ppm and an aluminum content of 612 ppm.

[0025]

Comparative Example 2 In the same manner as in Example 2, a slurry having a slurry concentration of 31.4% by weight, in which the olefin copolymer was suspended in liquid propylene, was obtained. This slurry liquid 6
07g, 50% aqueous sodium hydroxide solution of pH 12.2
0 ml was added and mixed vigorously for 30 minutes at 25 ° C.
Thereafter, the mixture was allowed to stand for 30 minutes, and the aqueous phase was separated. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 69.2% by weight, a propylene content of 26.7% by weight, and a 5-ethylidene-2-norbornene content of 4.1% by weight. The number average molecular weight Mn was 291,000, the weight average molecular weight Mw was 824,000, and Mw / Mn was 2.8. The vanadium content was as high as 7.2 ppm.
The aluminum content was 283 ppm. The copolymer in the slurry before the deashing had a vanadium content of 1
4.1 ppm, aluminum content was 540 ppm.

[0026]

Comparative Example 3 In the same manner as in Example 3, a slurry having a slurry concentration of 26.8% by weight in which the olefin copolymer was suspended in liquid propylene was obtained. This slurry liquid 5
100 ml of a mixture of methyl alcohol and cyclohexane (volume ratio 70:30) was added to 92 g,
And vigorously stirred and mixed for 30 minutes, and then allowed to stand for 30 minutes to separate the upper and lower layers containing the olefin copolymer. The upper layer was degassed to remove unreacted monomers, and dried under vacuum to recover an olefin copolymer. The vanadium content of this olefin copolymer was as high as 6.1 ppm. The aluminum content was 277 ppm. The copolymer in the slurry before the deashing had a vanadium content of 1
7.5 ppm, aluminum content was 626 ppm.

[0027]

Comparative Example 4 In the same manner as in Example 1, the slurry liquid 59 in which the olefin copolymer was suspended in liquid propylene was used.
8 g were obtained. The slurry concentration in this slurry liquid was 28.
It was 3% by weight. 400 ml of water was added to this slurry liquid, and the mixture was vigorously stirred and mixed at 20 ° C. for 20 minutes. Next, in the second stage, a mixed solution of 100 ml of methanol and 45 ml of toluene was added and stirred for 30 minutes. Thereafter, the mixture was allowed to stand for 30 minutes, and the aqueous phase was separated. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 68.4% by weight, a propylene content of 26.1% by weight, and 5-ethylidene-2.
The norbornene content was 5.5% by weight; The number average molecular weight Mn was 284,000, the weight average molecular weight Mw was 762,000, and Mw / Mn was 2.7.
The vanadium content was as high as 7.2 ppm. The aluminum content was 250 ppm. The copolymer in the slurry before the deashing had a vanadium content of 18.2 p.
pm, and the aluminum content was 593 ppm.

[0028]

According to the demineralization method of the present invention, the catalyst residue can be effectively removed from the particulate olefin-based copolymer produced in the suspension polymerization method. An olefin copolymer having an extremely low vanadium content of 5 ppm or less can be easily obtained.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-214705 (JP, A) JP-A-4-216803 (JP, A) JP-A-52-112685 (JP, A) JP-A-49-1979 50067 (JP, A) JP 48-16063 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 6/08

Claims (1)

(57) [Claims] An olefin copolymer obtained by suspension polymerization of ethylene and propylene or ethylene and propylene and a conjugated diene hydrocarbon using a vanadium compound and an organoaluminum compound as catalysts. (A) an alcohol, an aliphatic hydrocarbon, an alicyclic carbon
Mixed with a good solvent selected from the group consisting of hydrogenated hydrocarbons and aromatic hydrocarbons ( however, the amount of good solvent depends on the amount of unreacted liquid
The weight ratio to pyrene is in the range of 0.01 to 0.40.
To so that), then, (b) adding water or an aqueous alkaline solution, the catalyst residues elastomeric olefinic copolymer is extracted into the aqueous phase, demineralization method of elastomeric olefin copolymer.