JP3022904B2 - Purification method of 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 catalyst residues can be easily obtained. For this reason, conventionally, the solution polymerization method has been 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.

[0007] In order to solve the above-mentioned problem 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, thereby producing the catalyst in the polymerization step. It has been studied to reduce the vanadium content of the olefin-based copolymer itself. At the same time, it was studied to improve the demineralization step so that vanadium in the olefin-based copolymer could be more effectively removed. Conventionally studied methods of demineralization include, for example, adding a hydrochloric acid, acetic acid, an extract such as an aqueous solution of caustic soda, a complexing solution such as tartaric acid or gluconic acid, and an oxidizing agent to the slurry obtained in the polymerization step, and then adding There is a method of mixing an organic solvent such as toluene (Japanese Patent Publication No. 46-5156). In addition, a method of adding an alcohol, an aqueous solution of caustic soda, or an aqueous solution of tartaric acid to the slurry at a pressure higher than the polymerization pressure and decalcifying the slurry (Japanese Patent Publication No. 48-16063) was also studied. Further, a method of adding polyether diamine or polyether monoamine to the slurry after polymerization and washing with water (Japanese Patent Publication No. 46-6985), or a method of adding a good solvent and a surfactant and then adding water. (JP-A-60-69112) was 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.

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

[0010]

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 non-conjugated diene hydrocarbon, using a vanadium compound and an organoaluminum compound as catalysts, First, a good solvent and an alcohol are mixed with the slurry obtained in the polymerization step, and then, aqueous hydrogen peroxide and water or an alkaline aqueous solution are added, and the catalyst residue in the elastomeric olefin-based copolymer is separated into an aqueous phase. Is extracted.

First, the slurry obtained in the polymerization step is
As a first step, add a good solvent and alcohol, stir,
Mix. At this stage, it is considered that the olefin-based copolymer particles in the slurry liquid swell due to the added good solvent, and the vanadium compound in the catalyst residue contained in the particles reacts with the alcohol.

The amount of the good solvent to be added is preferably in the range of 0.01 to 0.40 by weight relative to the unreacted liquid propylene, and more preferably in the range of 0.02 to 0.30. Particularly preferred. 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, so that the catalyst residue is not sufficiently extracted. On the other hand, if it is more than 0.40, the produced olefin polymer dissolves in the added good solvent, so that there is a problem that the viscosity of the slurry liquid increases.

The amount of the alcohol to be added is preferably adjusted so as to be in the range of 0.02 to 20 and more preferably in the range of 0.5 to 10 in terms of a weight ratio to the produced olefin polymer. When the amount of alcohol added to the produced olefin polymer is less than 0.02, the vanadium compound in the catalyst residue does not completely react with alcohol, and is not sufficiently extracted in the subsequent step. On the other hand, even if the addition amount of the alcohol exceeds 20, the catalyst residue is not effectively extracted any more, so that the alcohol is wasted.

The ratio of alcohol to good solvent is 1/10 to 10
A range of 100/1 (volume ratio) is preferable. Temperature is -10
The range of -60 ° C is preferred.

The alcohol and the good solvent may be added simultaneously. In this case, the alcohol and the good solvent may be added as a mixture, or they may be added separately. Alternatively, the alcohol may be added first, followed by the good solvent, or vice versa.

As the alcohol, those which can be represented by ROH are preferable. Here, R is an alkyl group having 1 to 12 carbon atoms,
Alternatively, it is an arylalkyl group. Specifically, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-amyl alcohol, isoamyl alcohol, hexyl alcohol, octyl alcohol, nonyl Aliphatic saturated alcohols such as alcohol, decyl alcohol, undecyl alcohol, dodecyl alcohol,
Alicyclic alcohols such as cyclopentanol and cyclohexanol, and aromatic alcohols such as benzyl alcohol and cinnamyl alcohol are used. Most preferred among these are aliphatic saturated alcohols.

As the good solvent, one having a solubility parameter of 7.3 to 9.5 is used. If the solubility parameter is within this range, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons,
Any type of solvent such as ethers, ketones, esters and the like can be used. Examples of such a solvent include n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, cycloheptane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, Ethylbenzene, styrene,
Examples include methyl ethyl ketone, diethyl ether, dipropyl ether, ethyl acetate, acetic acid, chloroform, tetrachloroethane and the like. However, a solvent having a solubility parameter smaller than 7.3 is not preferable because a swelling effect of the polymer is small, and a solvent larger than 9.5 is not preferable because the catalyst removing effect is small.

As a second step, hydrogen peroxide and water or an aqueous alkali solution are added to the slurry liquid containing the good solvent and the alcohol, and the mixture is stirred to oxidize the catalyst residue in the olefin copolymer particles to form an aqueous solution. Extract into the aqueous phase while enhancing the properties. Hydrogen peroxide is preferably added as an aqueous solution having a concentration of about 3 to 60%. In the method of the present invention, hydrogen peroxide and either water or an aqueous alkali solution may be added first. These may be added simultaneously.

The amount of hydrogen peroxide added is from 0.01 to 5000 per mole of the vanadium compound used as the catalyst.
It is preferably in the range of mol, particularly preferably in the range of 0.1 to 1000 mol. If the amount of hydrogen peroxide is less than 0.01 mol per mol of the vanadium compound, the vanadium compound is not sufficiently oxidized, which is not preferable. On the other hand, if the added amount of hydrogen peroxide is more than 5000 mol, the produced olefin-based copolymer itself may be oxidized, which is not preferable.

The amount of the water or the aqueous alkali solution is preferably in the range of 0.01 to 10% by weight based on the weight of the olefin copolymer. The range of -60 ° C is preferred. 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 water or the aqueous alkaline solution, those having a pH of 5.5 to 12 are used. In the present invention, the aqueous alkaline solution refers to an aqueous solution of an alkaline compound,
Specifically, an aqueous caustic soda solution, an aqueous caustic potash solution, an aqueous ammonia solution and the like are included. However, an alkaline aqueous solution having a pH of more than 12 is not preferable. This is because the catalyst residue hardly dissolves. Water having a pH of 5.5 or more is preferable. This is because if water having a pH of less than 5.5 is used, there is a high risk of corrosion of the device.

[0022]

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

[Example 1] 500 g of liquid propylene and 5-
14 ml of ethylidene-2-norbornene, 2.9 mmol of diethylaluminum chloride and 0.2 mmol of diethylzinc were charged. Then, the polymerization temperature was set at 25 ° C.
While stirring the contents, while supplying ethylene at a pressure higher by 2 kg / cm ² and G than the internal pressure of the autoclave, a solution prepared by dissolving 0.05 mmol of vanadium triacetylacetonate in 4 ml of toluene was added. The polymerization was started by press-fitting. The polymerization was carried out for 20 minutes. As an activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate mixed at a molar ratio of 1: 9 was used,
0.15 mmol of this mixture was dissolved in toluene and 3 m
The solution of 1 was continuously added from the start to the end of the polymerization. After a lapse of 20 minutes, 590 g of a slurry liquid was obtained. The slurry concentration of this slurry liquid was 27.7% by weight. The slurry concentration is It was calculated by the following formula. First, 40 ml of toluene was added as a good solvent to this slurry liquid, and then 50 ml of methanol was added, followed by vigorous stirring at 20 ° C. for 10 minutes. Then, 10 ml of a 3% aqueous solution of hydrogen peroxide was added,
Under stirring, 400 ml of an aqueous solution of caustic soda having a pH of 10 was added, the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes.
The aqueous phase was separated 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 and the like was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 61.9% by weight,
Propylene content of 29.4% by weight, 5-ethylidene-
The content of 2-norbornene was 8.7% by weight. Number average molecular weight Mn is 296,000, weight average molecular weight Mw
Was 781,000, and Mw / Mn = 2.6. The vanadium content was 3.1 ppm and the aluminum content was 235 ppm. In addition, the copolymer in the slurry liquid before deashing had a vanadium content of 19.9 ppm,
The aluminum content was 612 ppm.

[Example 2] 500 g of liquid propylene, 5-g
12 ml of ethylidene-2-norbornene, 2.5 mmol of diethylaluminum chloride and 0.1 mmol of diethylzinc were charged. Then, the polymerization temperature was set at 25 ° C.
While stirring the contents and supplying ethylene at a pressure higher than the internal pressure of the autoclave by 2 kg / cm ² and G, while dissolving 0.04 mmol of vanadium triacetylacetonate in 3 ml of toluene. The polymerization was started by press-fitting. The polymerization was performed for 30 minutes. As an activator, a mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 2: 8 was used,
0.12 mmol of this mixture was dissolved in toluene and 5 m
The solution of 1 was continuously added from the start to the end of the polymerization. After 30 minutes, 592 g of a slurry liquid was obtained. The slurry concentration in the slurry liquid is 28.1% by weight
Met. The slurry concentration was calculated in the same manner as in Example 1. First, cyclohexane 40
Then, 60 ml of isopropyl alcohol was added, and the mixture was vigorously stirred at 20 ° C. for 10 minutes. Then, 10 ml of a 3% aqueous solution of hydrogen peroxide was added, and 400 ml of a caustic potassium hydroxide solution having a pH of 9 was further added under stirring, and the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry. From the slurry liquid from which the aqueous phase was separated, unreacted monomers were removed by degassing, and a small amount of remaining cyclohexane and the like were removed by a vacuum dryer. The obtained copolymer had an ethylene content of 63.7% by weight, a propylene content of 29.2% by weight, and a 5-ethylidene-2-norbornene content of 7.1% by weight. The number average molecular weight Mn is 243,000, and the weight average molecular weight Mw is 61
5,000, and Mw / Mn = 2.5. Vanadium content is 2.8 ppm, aluminum content is 2
It was 25 ppm. The copolymer in the slurry before the deashing had a vanadium content of 15.7 ppm and an aluminum content of 519 ppm.

Example 3 In a stainless steel autoclave having a content of 2 liters, 500 g of liquid propylene, 14 ml of dicyclopentadiene, 2.8 mmol of diethylaluminum chloride and 0.1 mmol of diethylzinc were placed.
l was charged. Then, the polymerization temperature was set at 23 ° C.
While stirring the contents, while supplying ethylene at a pressure 3 kg / cm ² , G higher than the internal pressure of the autoclave,
A solution obtained by dissolving 0.03 mmol of vanadium triacetylacetonate in 3 ml of toluene was injected under pressure to initiate polymerization. The polymerization was performed for 30 minutes. A mixture of ethyl monochloromalonate and ethyl dichloromalonate in a molar ratio of 3: 7 was used as an activator, 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 50 minutes, 585 g of a slurry liquid was obtained. The slurry concentration in the slurry liquid was 28% by weight. still,
The slurry concentration was calculated in the same manner as in Example 1. First, 30 ml of toluene and then 70 ml of ethanol were added to this slurry solution, and the mixture was vigorously stirred at 30 ° C. for 10 minutes. Next, 15 m of a 3% aqueous solution of hydrogen peroxide
of sodium hydroxide aqueous solution having a pH of 9 while stirring.
0 ml 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. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene and the like was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 58.
The content of propylene was 33.4% by weight, and the content of dicyclopentadiene was 7.8% by weight. The number average molecular weight Mn was 316,000, the weight average molecular weight Mw was 841,000, and Mw / Mn was 2.7.
The vanadium content was 4.8 ppm and the aluminum content was 327 ppm. In addition, the copolymer in the slurry liquid before deashing had a vanadium content of 12 ppm and an aluminum content of 591 ppm.

Example 4 500 g of liquid propylene and 2.5 mmol of diethylaluminum chloride were charged into a 2 liter stainless steel autoclave.
Hydrogen was charged to a gauge pressure of 0.4 kg / cm ² . Then, the polymerization temperature was set to 20 ° C., and while stirring the contents, ethylene was supplied at a pressure 2 atmospheres higher than the internal pressure of the autoclave, and 0.03 mmol of vanadium triacetylacetonate was dissolved in 3 ml of toluene. The resulting solution was press-fitted to initiate polymerization. The polymerization was carried out for 35 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 0.15 mmol of this mixture in toluene to make 10 ml was completed from the start of polymerization. Added continuously over time. After 35 minutes, 577 g of a slurry liquid was obtained. The slurry concentration in the slurry liquid was 31.4% by weight. The slurry concentration is
Calculation was performed in the same manner as in Example 1. First, 40 ml of cyclohexane was added to the slurry, and then 50 ml of ethanol was added, followed by vigorous stirring at 20 ° C. for 10 minutes.
Next, 10 ml of a 3% aqueous solution of hydrogen peroxide was added,
Under stirring, 400 ml of an aqueous solution of caustic soda having a pH of 11 was further added, the mixture was stirred for 30 minutes, and then allowed to stand for 30 minutes to separate an aqueous phase from the slurry. From the slurry liquid from which the aqueous phase was separated, unreacted monomers were removed by degassing, and a small amount of remaining cyclohexane and the like were removed by a vacuum dryer. The resulting copolymer has an ethylene content of 5
7.6% by weight and propylene content was 42.4% by weight. The number average molecular weight Mn is 217,000, the weight average molecular weight Mw is 527,000, and Mw / Mn = 2.4.
Met. The vanadium content was 2.5 ppm and the aluminum content was 220 ppm. The copolymer in the slurry before the deashing had a vanadium content of 11 pp.
m and the aluminum content were 489 ppm.

Comparative Example 1 In the same manner as in Example 1, a slurry liquid of an olefin polymer having a slurry concentration of 28.1% by weight was obtained. To 592 g of this slurry liquid, 40 ml of toluene was added as a good solvent, and 50 ml of methanol was added.
10 ml of a 3% concentration hydrogen peroxide solution and 400 ml of a pH 10 aqueous solution of caustic soda were added and stirred for 30 minutes. Thereafter, the mixture was allowed to stand for 30 minutes, and the aqueous phase was separated. From the slurry liquid from which the aqueous phase was separated, unreacted monomers were removed by degassing,
A small amount of the remaining toluene and the like was removed by a vacuum dryer.
The obtained copolymer had an ethylene content of 62.2% by weight, a propylene content of 29.4% by weight, and a 5-ethylidene-2-norbornene content of 8.4% by weight. The number average molecular weight Mn was 301,000, the weight average molecular weight Mw was 782,000, and Mw / Mn = 2.6. The vanadium content was as high as 7.8 ppm.
The aluminum content was 385 ppm. The copolymer in the slurry before the deashing had a vanadium content of 1
9.6 ppm, aluminum content was 602 ppm.

Comparative Example 2 A slurry having a slurry concentration of 28.0% by weight was obtained in the same manner as in Example 1. To 590 g of this slurry liquid, 10% hydrogen peroxide solution having a concentration of 3% was added.
ml and 400 ml of an aqueous solution of caustic soda having a pH of 10 were added, and the mixture was vigorously stirred for 30 minutes and then allowed to stand for 30 minutes to separate an aqueous phase. Unreacted monomers were removed from the slurry liquid from which the aqueous phase was separated by degassing, and a small amount of remaining toluene and the like was removed by a vacuum dryer. The obtained copolymer had an ethylene content of 60.9% by weight and a propylene content of 3%.
The content of 0.6% by weight and the content of 5-ethylidene-2-norbornene was 8.5% by weight. Number average molecular weight Mn is 29
8,000, the weight average molecular weight Mw was 779,000, and Mw / Mn was 2.6. The vanadium content was as high as 8.0 ppm. Aluminum content is 402
ppm. In addition, the copolymer in the slurry liquid before deashing had a vanadium content of 19.8 ppm and an aluminum content of 607 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-4-216803 (JP, A) JP-A-4-214705 (JP, A) JP-A-1-149804 (JP, A) JP-A 48-48 37482 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08F 6/08

Claims (1)

(57) [Claims] 1. An elastomeric olefin copolymer obtained by suspension polymerization of ethylene and propylene or ethylene and propylene and a non-conjugated diene hydrocarbon using a vanadium compound and an organoaluminum compound as catalysts. (A) mixing a good solvent and an alcohol into the polymerization system, and then (b) adding hydrogen peroxide and water or an alkaline aqueous solution to remove the catalyst residue in the elastomeric olefin-based copolymer. A method for purifying an elastomeric olefin copolymer to be extracted into an aqueous phase.