JPH03182509A - Production of ethylene-alpha-olefin copolymer - Google Patents

Abstract

PURPOSE:To produce an ethylene-alpha-olefin copolymer improved in transparency, flexibility and mechanical strength by bringing a slurry of a specified ethylene-alpha- olefin copolymer in a hydrocarbon solvent into contact with water. CONSTITUTION:Ethylene is copolymerized with a 3-10C linear alpha-olefin at 40-65 deg.C under a pressure of 1-30kg/cm<2> in a hydrocarbon solvent in the presence of a catalyst system comprising a vanadium chloride compound or an alkoxylated vanadium compound (e.g. VoCl3) and an organic aluminum chloride compound of the formula (wherein n is 1.0-3.0; and R is a 2-6C alkyl residue), a hydrocarbon-insoluble copolymer and a hydrocarbon-soluble copolymer to obtain a copolymer solution containing a hydrocarbon-insoluble copolymer and a hydrocarbon-soluble copolymer. The copolymer solution is heated to a temperature above Ts deg.C defined in the table and mixed with 0.5-10 pts.vol., per pt.vol. of the solution, water or hot water to transfer the V compound and the Al compound from the copolymer solution into the water phase.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention relates to a method for producing an ethylene-a-olefin copolymer, and more specifically, to a method for producing an ethylene-a-olefin copolymer.
The present invention relates to a method for efficiently purifying an ethylene-α-olefin copolymer having excellent transparency, flexibility, and mechanical strength, which is composed of a chain olefin, and obtaining a copolymer with a small amount of double polymerization catalyst residue.

<Prior Art> Olefin polymers are molded into films, tapes, sheets, blow molded products, injection molded products, etc., either alone or mixed with other polymers, and are used in many fields.

Conventionally, it consists of ethylene and α-olefin.

Many proposals have been made regarding methods of producing copolymers. For example, in Japanese Patent Publication No. 45-21212, 4
A method for producing a copolymer of ethylene and α-olefin using a catalyst consisting of a vanadium compound and an organoaluminum halide at a temperature of 0 to 110°C is disclosed.

Furthermore, Japanese Patent Publication No. 47-26185 discloses that a halogenated lower aliphatic hydrocarbon or a hydrocarbon having 3 to 5 carbon atoms is used as a reaction medium, and a catalyst system consisting of a combination of a VOX3 compound and an organoaluminum compound is used to produce a soft A method of making an olefin copolymer is disclosed.

Furthermore, JP-A-63-17912 discloses slurry polymerization of ethylene and α-olefin at a temperature of -20°C to +30°C using a catalyst system consisting of a soluble vanadium compound and an organic chlorinated aluminum compound. A method is disclosed.

Apart from these ethylene-〇-olefin copolymers catalyzed by vanadium compounds, methods for producing ethylene-α-olefin copolymers using titanium compound catalysts have also been disclosed, but in general, copolymers catalyzed by titanium compounds are 1
It has a wide molecular weight distribution and composition distribution, and therefore, when used as a material for food packaging films, for example, it has disadvantages such as insufficient heat sealing performance.

On the other hand, the vanadium compound-catalyzed copolymer has a narrow molecular weight distribution and the composition can be controlled uniformly, as described above.

Many polymerization methods have been proposed.

However, copolymers with high ethylene content have low solubility in hydrocarbon solvents, and even in a polymerization reaction system, the copolymers precipitate in the form of particles.

It exhibits a so-called slurry state. In this case.

Catalyst components are trapped inside the copolymer particles 2
Even if it is brought into contact with a polar medium such as water, which is an extractant for the catalyst compound after polymerization, the extraction efficiency is low.

As a result, the catalyst component remains in the copolymer that is finally recovered.

In general, if a large amount of transition metal compound remains in a copolymer, it may become discolored over time or contaminate articles that come into contact with the copolymer.

This may cause practical problems, and vanadium compounds are particularly prone to this, and in extreme cases, the copolymer itself may even undergo decomposition or crosslinking deterioration.

By the way, when producing an ethylene-a-olefin copolymer with a high ethylene content by a so-called slurry polymerization method, it is necessary to select a solvent and perform low-temperature polymerization.
It is disadvantageous in terms of equipment and energy. On the other hand, when producing by a solution polymerization method, polymerization is required at a relatively high temperature, which reduces catalyst efficiency and is disadvantageous in terms of cost. For this reason, it has been strongly desired to realize a method for producing ethylene-α-olefin copolymers in a state in which a solvent-insoluble polymer and a solvent-soluble polymer coexist, that is, in a slurry state, which is advantageous in terms of equipment, energy, and cost. There is.

The present inventors previously used a three-component system of vanadium compound/organoaluminium compound/halogenated ester compound M as a catalyst system.

In addition to limiting the proportion, the polymerization temperature.

It was discovered that by appropriately selecting a polymerization solvent, an ethylene-α-olefin copolymer with a uniform composition and a narrow molecular weight distribution could be obtained even in the coexistence of a solvent-insoluble polymer and a solvent-soluble polymer, and was granted a patent. An application was filed (Japanese Patent Application No. 142522-1983). Although a useful ethylene-α-olefin copolymer can be obtained by this copolymerization method, since the copolymerization system contains a solvent-insoluble polymer, vanadium compounds and organoaluminum compounds used as catalysts were recovered in 9 cases. Sometimes a large amount remained in the polymer.

<Problems to be Solved by the Invention> The purpose of the present invention is to solve these problems and to provide a method for copolymerizing a solvent-insoluble polymer and a solvent-soluble polymer in a state in which a solvent-insoluble polymer and a solvent-soluble polymer coexist, which are advantageous in terms of equipment, energy, and cost. To efficiently purify a homogeneous ethylene-α-olefin copolymer with a narrow molecular weight distribution and a composition of 9 to obtain a copolymer with reduced amounts of vanadium compounds and aluminum compounds remaining in the copolymer. This method realizes a uniform composition of 9 with a narrow molecular weight distribution.

Moreover, it is an object of the present invention to provide an ethylene-α-olefin copolymer which has a relatively high amount of ethylene bonds and has a small amount of residual vanadium compounds and residual aluminum compounds.

Means to solve problems〉 The inventors of the present application aimed to achieve the above object.

We have been carefully considering this. As a result, the hydrocarbon solvent slurry of the ethylene-α-olefin copolymer synthesized under specific copolymerization reaction conditions becomes a homogeneous solution in a specific temperature range, and this solution and water as an extraction medium are mixed together. It was discovered that by contacting and mixing, an ethylene-α-olefin copolymer with a reduced amount of residual vanadium compounds and a reduced amount of residual aluminum compounds could be obtained, and the present invention was achieved.

That is, 9 the present invention relates to a chlorinated vanadium compound or an alkoxy group-containing vanadium compound and a compound having the general formula RnAlCl3-n.
(In the formula, n is a number of 1.0 to 3.0, R is a number of carbon atoms of 2 to 6
represents an alkyl residue. ) Using a catalyst system consisting of an organochlorinated aluminum compound represented by By copolymerizing in the presence of a dissolved copolymer.

A copolymer solution containing a hydrocarbon solvent-insoluble copolymer and a hydrocarbon solvent-soluble copolymer was obtained.9 Next, the copolymer solution was heated at the following temperature Ts.
The heated copolymerization liquid and the copolymerization liquid are heated to 0.
．． Production of an ethylene-α-olefin copolymer characterized in that vanadium compounds and aluminum compounds contained in a copolymerization liquid are transferred to an aqueous phase by mixing 5 to 10 times the volume of water or hot water. It is related to the method.

Ts (℃): The higher of the following T and (copolymerization temperature + 5℃) T / (℃) = 107.5-50AO However, CA
o is α-olefin content (% by weight) in the ethylene-α-olefin copolymer In the present invention, ethylene and a chain α-olefin having 3 to 10 carbon atoms are used as copolymerization components.

As a chain α-olefin having 3 to 10 carbon atoms.

Specifically, propylene, 1-butene, 1-pentene, 1-
Hexene, 4-methyl-1-pentene.

Examples include 1-octene and 1-decene.

Propylene and 1-butene are preferred, and 1-butene is particularly preferred.

The copolymerization catalyst used in the present invention includes a chlorinated vanadium compound or an alkoxy group-containing vanadium compound described below,
General formula -RnAIC13-nC In the formula, n is 1.0 to 3.0
, R represents an alkyl residue having 2 to 6 carbon atoms. ) is a catalyst system consisting of an organic chlorinated aluminum compound represented by

Examples of chlorinated vanadium compounds or alkoxy group-containing vanadium compounds include VOCIs.

VO(OCH3)C12,VO(OCH3)2C1,V
O(OCH3)3゜VO(OC2H5)C12,VO(
OC2H5)2C1,VO(OC2H5)3゜VO(O
C3H7)C12,VO(OC3H7)2C1,VO(
OC3H7)3゜VO(OisoC3H7)C12,V
O(OisoC3H7)2C1,.

VO(OisoC3H7)3. VCl3. VC
l4. V(OCH3)3゜v(OCH2COOCH
3) 3) A mixture of these can be exemplified.

In the present invention, it is necessary to use the above vanadium compound. On the other hand, if a titanium compound is used, a non-uniform copolymer with one composition is produced, resulting in poor purification efficiency, which is not preferable.

Note that in the present invention, purification refers to extracting and transferring the copolymerization catalyst residue to the aqueous phase, which will be described later.

Moreover, as the above-mentioned organic chlorinated aluminum compound.

(C2H5)2AIC1, (C4H9)2AIC1,,
(CsH+3)2A1cl.

(C2H5)1.5AI C11,5・ (C4H9)
1. sAI C1t, s. (C6H13) 1.5A
I C11, so C2H5Al CI 2. C4
Examples include H9Al C12°C6H13Al CI 2.

In the present invention, in addition to these copolymerization catalyst components, an activator for copolymerization reaction or a regulator for compositional distribution or molecular weight distribution can also be used. For example, a halogenated ester compound as a narrowing agent for the composition distribution of the copolymerization reaction activator.

The use of hydrogen or the like as a molecular weight regulator is preferred for controlling the structure of the copolymer during industrial implementation. In this case, the halogenated ester compound is 9, for example,
A compound represented by the following general formula: (hydrocarbon group) is effective, preferably a compound in which all the substituents of R'' are chloro-substituted, or a compound having a phenyl group and a chloro-substituted alkyl group, more preferably perchlorocrotonic acid ester or , phenyl dichloroacetate are very effective. Specifically, ethyl dichloro acetate, methyl trichloro acetate, ethyl trichloro acetate, methyl dichlorophenylacetate, ethyl dichlorophenylacetate, methyl perchlor crotonate, ethyl perchlor Examples include crotonate, propylperchlorocrotonate, isopropylperchlorocrotonate, butylperchlorocrotonate, cyclopropylperchlorocrotonate, phenylperchlorocrotonate, and the like.

Soluble vanadium compounds in copolymerization reactions.

That is, the concentration of the ruhanadium compound dissolved in the hydrocarbon solvent during the copolymerization reaction is from 0.00005 mmol/l to 5 mmol/l, preferably from 0.0001 mmol/l to 1 mmol/'! The molar ratio of the organic chlorinated aluminum compound to the soluble vanadium compound is preferably 2.5 or more.

The copolymerization in the present invention is preferably carried out in a hydrocarbon solvent having 5 to 1 carbon atoms.

The hydrocarbon solvent includes aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, etc., cycloaliphatic hydrocarbons such as cyclohexane, methylcyclopentane, methylcyclohexane, etc., benzene, toluene, xylene, etc. Examples include aromatic hydrocarbons such as.

Particularly, it is preferable to use pentane, hexane, or heptane because the stability of the copolymerization reaction and the copolymerization operation are easy to purify the copolymer after copolymerization.

α-olefins such as polyester, propylene, 1-7” tenene, l-hair tenene, 1-hexene, etc.

A monomer solution such as that dissolved in the above-mentioned hydrocarbon solvent having 5 to 10 carbon atoms can also be used as a medium for copolymerization.

In the present invention, the copolymerization temperature is preferably carried out in the range of 40"C to 65C. If the polymerization temperature is less than 40C, the copolymerization reaction rate decreases and the copolymerization rate per unit time decreases. Not only does the yield decrease, but also special cooling equipment is required to remove the heat of the copolymerization reaction, which is disadvantageous in industrial implementation.
When the temperature exceeds 5°C, the 9 reaction system gradually becomes a homogeneous solution.

In addition to the increased viscosity and the need for a large amount of power for stirring and mixing,
This results in disadvantages such as the amount of copolymer produced per unit amount of copolymerization catalyst decreases, or the copolymerization reaction becomes unstable and the desired copolymer cannot be obtained.

Copolymerization is carried out under atmospheric pressure or under pressure, and 1 to 3
Preferably it is carried out at 0 kg/cm2, especially at 1
Preferably, the weight is between 20 kg/cm2 and 20 kg/cm2. The average residence time of the copolymerization reaction solution is 10 to 180 minutes, preferably 20 to 120 minutes, and the copolymer concentration is 12 weight percent or less when it is 15 weight percent or less.
This is preferable from the viewpoint of stabilizing the state of the copolymerization reaction slurry liquid. In the present invention, the slurry liquid refers to a copolymerization liquid in which a hydrocarbon solvent-insoluble copolymer and a hydrocarbon solvent-soluble copolymer coexist.

Specific examples of the ethylene-α-olefin copolymer of the present invention are as described above.

The ethylene content in the ethylene-α-olefin copolymer is preferably 88 to 96% by weight, and if it is less than 88% by weight, the particle size of the slurry particles during copolymerization becomes large and a stable slurry liquid cannot be obtained. Alternatively, the produced copolymer becomes too soft, resulting in a rubbery copolymer that is difficult to form into a film.

On the other hand, if the ethylene content exceeds 96% by weight.

The temperature required to heat the copolymer slurry liquid and dissolve the copolymer in the copolymerization solvent is high, which is disadvantageous because special equipment and an excessively large heat source are required for heating. Or, an extremely highly crystalline copolymer chain with continuous ethylene chains is generated in the copolymer chain, resulting in poor heat sealing performance, and a copolymer with good heat sealing performance cannot be purified. This is not preferable in light of the purpose of the present invention, which is to collect the waste in a state in which it has been removed.

In the method of the present invention, after the copolymerization reaction is completed.

By heating a slurry liquid containing a copolymer to the above-mentioned temperature Ts or higher, and mixing 0.5 to 10 times the volume of water or warm water to the heated liquid.

It is necessary to transfer the vanadium compound and aluminum compound contained in the liquid to the aqueous phase.

The ethylene-α-olefin copolymer obtained by the copolymerization reaction exists together with the hydrocarbon solvent in the form of a slurry liquid in which a soluble portion and an insoluble portion are mixed in the hydrocarbon solvent at the copolymerization temperature.

By setting the temperature higher than Ts, most of the copolymer becomes soluble, and the purification efficiency, that is, the efficiency of extraction and transfer of vanadium compounds and aluminum compounds to the aqueous phase is improved.

The heating temperature in this case can be arbitrarily selected as long as it is higher than Ts, but in order to avoid wasting the heat source unnecessarily during industrial implementation, the heating temperature must be below the above Tu. is preferred.

As described above, the preferable heating temperature for industrial implementation varies depending on the α-olefin content in the ethylene α-olefin copolymer, but specifically, it is 5°C or more higher than the copolymerization temperature. , and about 60°C to 100°C.

After the copolymerization reaction is completed, unreacted monomers are removed from the polymerization reactor either before the slurry is heated or when the temperature of the slurry is increased.

Although it is preferable to discharge the liquid to the outside of the system in order to facilitate subsequent operations, the present invention is not particularly limited thereto.

In the method of the present invention, the amount of water or warm water mixed and brought into contact with the heated copolymerization solution is preferably 0.5 to 10 times the volume of the copolymerization solution. If the amount is less than 0.5 times, the extraction efficiency of vanadium compounds and aluminum compounds will decrease, while if it exceeds 10 times the amount, the copolymer will precipitate, or the stirring and mixing equipment with the copolymerization liquid or the process wastewater will be extremely large. It is undesirable because it increases in quantity and quantity. A particularly preferred capacity ratio is 1 to 5 times the amount.

The temperature of the water or hot water brought into contact with the copolymerization liquid is not particularly limited, but it is preferably such a temperature that the temperature of the copolymerization liquid after mixing and contact is not less than Ts and not more than Tu.

The method of contacting the copolymerization liquid with water or hot water is not particularly limited, but it is preferable to use mixing equipment with a large stirring effect in order to improve the extraction efficiency of vanadium compounds and aluminum compounds. A stirring tank with an agitator.

A so-called line mixer or static mixer, which performs mixing in a conduit, is preferably used for this purpose.

The copolymerization solution thus brought into contact with water or warm water is allowed to stand again and is separated from the washing water.

It is preferable that the copolymer be sent to an operation step of evaporative removal of the hydrocarbon solvent and recovery of the copolymer, but if the copolymer recovery operation uses steam or water, such as a steam stripping method, Separation of the copolymerization liquid and washing water can also be omitted.

When recovering the copolymer from the copolymerization solution.

In addition to the above steam stripping method, jacket heating is used without injecting water or steam.

After heating and pressurizing the copolymerization liquid, the hydrocarbon solvent is evaporated to obtain a copolymer. A so-called direct drying method may also be employed.

The copolymer is usually molded into a granular form called a pellet, but it is not necessarily limited to this and can be recovered in various forms such as a powder, a sheet, and a foamed granule. It is possible.

The copolymer obtained in this way is a good copolymer with a small residual amount of vanadium compounds and aluminum compounds and low discoloration.

<Example> The present invention will be specifically explained below with reference to Examples, but the present invention is not limited thereto.

Example 1 51 SUS polymerization vessel equipped with a stirring blade, 10/SUS equipped with a stirring blade and jacket, and an upper vaporized component extraction port
S-made pressure-resistant stirring tank (hereinafter referred to as "degasser") internal capacity 12
Copolymerization of ethylene and 1-butene was carried out continuously using equipment in which a mixer with a stirring blade of 11 rotations and 150 rpm (D) was connected to a static separation tank made of SUS with an internal volume of 50 rpm.

That is, 5 hexane was added as a polymerization solvent from the bottom of the 9 polymerization vessel.
// feed continuously at the rate of time.

On the other hand, the copolymerization liquid in the polymerization vessel from the top of the 9 polymerization vessel is always 51!
The copolymerization liquid was continuously extracted and introduced into a degasser. Furthermore, the copolymerization liquid was continuously drawn out from the side of the degasser, and the copolymerization liquid in the degasser was controlled to always be 51%.

Vanadium oxytrichloride as a copolymerization catalyst.

Ethylaluminum sesquichloride and ethyl dichlorophenylacetate at 0.025 mmol/hour, 0.60 mmol/hour, and 0.060 mmol/hour, respectively.
It was continuously fed into the polymerization vessel from the bottom of the polymerization vessel at a rate of 1 hour. As monomers, ethylene and l-butene were continuously fed into the polymerization vessel from the bottom of the polymerization vessel at a rate of 160 g/hour and 180 g/hour, respectively. Molecular weight was also adjusted using hydrogen.

The copolymerization reaction was carried out at 55° C. by circulating cooling water through a jacket attached to the outside of the polymerization vessel.

When the copolymerization reaction is carried out under the conditions described above.

An ethylene-1-butene copolymer was obtained in which a portion insoluble in the polymerization solvent and a portion soluble in the polymerization solvent coexisted.

A small amount of this copolymer solution was sampled and filtered through a 300-mesh wire mesh to separate the solvent-insoluble and soluble parts of the copolymer, and the weight ratio of each part was determined.
Insoluble portion/soluble portion = 52/48.

Meanwhile, while copolymerization continued, warm water was circulated through the jacket of the degasser to control the internal temperature of the degasser to 75°C. For the copolymerization liquid extracted from the degasser.

No copolymer particles were observed, indicating that the copolymer was completely dissolved in the hexane solvent.

75°C hot water is supplied at a rate of 3017 hours to the copolymerization liquid transfer piping after this degasser and the piping connected from the perpendicular direction, and the copolymerization liquid and hot water are mixed and then sent to the mixer. After further stirring and mixing, the mixture was sent to a static separation tank with a capacity of 50/ml. The copolymer liquid phase was extracted, poured into hot water, hexane was distilled off, the polymer was collected and dried, and the resulting copolymer was analyzed for catalyst residue components.

3) ppm in A12 o3, 4ppm in V205
There was a time. Also.

The 1-butene content in the copolymer was 7.7% by weight.

Comparative Example 1 In Example 1, the internal temperature of the degasser was the same as that of the polymerization tank <55
The temperature of the hot water supplied to the mixer is controlled at 55°C.
The same operation as in Example 1 was repeated, except that the test tube was placed in the same position as in Example 1.

What are the catalyst residue components in the recovered copolymer?

It was high at 76 ppm for A1□o3 and 25 ppm for V2O5.

Examples 2 and 3 and Comparative Examples 2 and 3 The same operation as in Example 1 was repeated by changing the degasser internal temperature and hot water temperature. The results are shown in Table 1.

Examples 4 to 12 and Comparative Examples 4 to 9 In Example 1, the type and addition rate of the vanadium compound supplied during copolymerization, the addition rate of the organoaluminum compound, the type and amount of the halogenated ester compound, ethylene,
The experiment was repeated with various changes such as the feed rate of 1-butene. The results are shown in Tables 2 and 3.

<Effects of the Invention> As explained above, the present invention provides ethylene-α with significantly reduced amounts of vanadium compounds and aluminum compounds, especially vanadium compounds, which are catalyst residue components.
- An olefin copolymer could be obtained.

that's all

Claims (4)

[Claims] (1) Chlorinated vanadium compound or alkoxy group-containing vanadium compound and the general formula RnAlCl_3_-_n (wherein, n is a number from 1.0 to 3.0, and R represents an alkyl residue having 2 to 6 carbon atoms.) Using a catalyst system consisting of an organochlorinated aluminum compound represented by
By copolymerizing a hydrocarbon solvent-insoluble copolymer and a hydrocarbon solvent-soluble copolymer in the coexistence, a copolymer solution containing a hydrocarbon solvent-insoluble copolymer and a hydrocarbon solvent-soluble copolymer is obtained, Next, the temperature of the copolymerization liquid is raised to the following temperature Ts or higher, and the temperature of the heated copolymerization liquid and the copolymerization liquid is 0.5 to 10%
A method for producing an ethylene-α-olefin copolymer, which comprises transferring a vanadium compound and an aluminum compound contained in a copolymerization solution to an aqueous phase by mixing water or warm water in an amount twice the volume. Ts (℃): The higher of the following Tl and (copolymerization temperature + 5℃) Tl (℃) = 107.5-5C_A_O However, C_A_O is the α-olefin content in the ethylene-α-olefin copolymer Amount (wt%) (2) The hydrocarbon solvent is a hydrocarbon solvent having 5 to 10 carbon atoms, the temperature during copolymerization is 40 to 65°C, and the ethylene content in the resulting ethylene-α-olefin copolymer is 88 to 96% by weight. %. The method according to claim (1). (3) The method according to claim 1, wherein the ethylene-α-olefin copolymer is an ethylene-propylene copolymer, an ethylene-butene-1 copolymer, or an ethylene-propylene-butene-1 copolymer. (4) The method according to claim (1), wherein the temperature at which the copolymerization solution is raised is Ts to Tu below. Tu (℃) = 127.5 ~ 5C_A_O However, C_A_O is the α-olefin content (wt%) in the ethylene-α-olefin copolymer