JPH08231643A - Production of acrylonitrile (co)polymer - Google Patents

Abstract

PURPOSE: To produce an acrylonitrile (co)polymer while suppressing the forma tion of a gel component by forming a vapor phase over the polymerization solution in the reactor, polymerizing the monomer while evaporating the mono mer at a specified temperature and polymerizing the monomer while condensing the formed vapor by keeping the temperature in the vapor phase at a specified value by external cooling. CONSTITUTION: 100 pts.wt. mixture comprising about 5-80wt.% acrylonitrile monomer and about 5-95wt.% styrene monomer, about 4-50 pts.wt. rubbery polymer (e.g. polybutadiene), about 0.001-5 pts.wt. polymerization initiator (e.g. t-butyl peroxypivarate) and optionally about 5-50 pts.wt. solvent (e.g. toluene) are fed into a reactor having two separate upper and lower cooling and heating jackets on the wall. While the monomer is being evaporate by heating the polymerization solution to 80 deg.C or above, it is polymerized. The temperature in a vapor phase formed over the polymerization solution is kept at 30-65 deg.C by cooling from the external of the wall of the reactor. Therefore, the formed vapor are condensed and then polymerized. After the reaction, the product is withdrawn, separated by filtration and dried to obtain a styrene/acrylonitrile copolymer not contaminated with a gelpolymer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The (co) polymerization of a monomer containing an acrylonitrile-based monomer as an essential component in a reaction vessel having a gas phase and a liquid phase is performed on the inner wall of the reaction vessel with an acrylonitrile-based (co) polymer. The present invention relates to a method for producing a (co) polymer without causing adhesion, and a polymerization reaction tank suitable for producing the polymer.

[0002]

2. Description of the Related Art As a method for polymerizing a (co) polymer containing an acrylonitrile-based monomer as an essential component, an emulsion polymerization method or a suspension polymerization method has hitherto been used. However, this method has a large problem in terms of global environmental problems and product quality because it generates a large amount of wastewater and contains emulsifiers and suspending agents in the product. Development has become an important issue.

However, in bulk / solution polymerization, heat cannot be removed by using water as a medium, and therefore, when the size of the reaction tank becomes large, how to remove heat of polymerization reaction is a problem.

Usually, when (co) polymerization containing an acrylonitrile-based monomer as an essential component, (co) polymerization is carried out in a reaction vessel in a state where a full liquid or a gas phase portion is present.

When the copolymerization is carried out in a full liquid, the heat removal is mainly due to the heat transfer from the wall surface, so that it is difficult to remove the heat in a large-sized reaction tank. Therefore, in order to perform the above heat removal, a coil tube having a complicated shape is provided inside the reaction tank, or an external heat exchanger is provided outside to circulate and cool the polymerization liquid.

However, in (co) polymerization containing an acrylonitrile-based monomer as an essential component, a gelled polymer is apt to adhere to the inner wall of the reaction vessel, and a coil or heat exchanger having a complicated shape for taking a heat transfer area is It was a disadvantage. Especially when the volume of the reaction tank increases, the heat transfer area requirement increases,
The device becomes complicated, and the problem of generation of gelled polymer increases.

When the volume of the reaction tank is 1 m ³ or more, especially more than 3 m ³ , it is advantageous to control the heat of polymerization by so-called evaporation latent heat by providing a vapor phase portion in the upper part to evaporate the vapor from the polymerization liquid. That is, since the heat generated by the polymerization is removed by the latent heat of vaporization, the reaction tank has a relatively simple structure, and the heat can be easily removed, so that the size of the reaction tank can be increased.

However, in this control system by latent heat of vaporization, when the vinyl-based monomer contains acrylonitrile, particularly in the case of copolymerization of styrene / acrylonitrile, the gas phase portion contains a gaseous monomer having a large acrylonitrile component, Therefore, another problem is that acrylonitrile-rich (co) polymer scale is likely to be formed on the wall of the gas phase part. Contains a lot of this acrylonitrile (co)
There was a big problem that the polymer scale gradually gelled and became insoluble in the solvent, and when it fell from the gas phase portion into the reaction tank, the resin obtained as a product became foreign matter. In particular, when the obtained copolymer is used as a film or a sheet, the presence of the polymer falling from the gas phase portion causes the generation of fish eyes. Further, the reaction apparatus is often stopped in order to remove the gel attached to the reaction tank, and a great amount of labor is required for its removal, which has been a serious problem in industrial production.

As a method for preventing polymer gel formation inside the gas phase, a method has been proposed in which a scale inhibitor is applied to the wall of the gas phase in the reaction tank. However, this method is limited to the case where the styrene-acrylonitrile-based monomer is polymerized in an aqueous medium, and in other methods such as the bulk polymerization and the solution polymerization method, the scale inhibitor is washed away with the monomer, so that the long-term It has the drawback that it cannot be used in continuous operation.

Further, the pressure inside the reaction tank is maintained at a pressure at which the polymerization liquid does not boil, and the gas above the reaction liquid is condensed by a cooling device provided inside or outside the reaction tank to allow the polymer to reach the inner wall of the reaction tank / cooler. The method of preventing the adhesion of the polymer and removing the heat of polymerization is described in, for example, Japanese Patent Publication Showa 56-15641 (Mitsubishi Rayon), USP 4677171 (Cosden Tech).
It has been proposed in, for example. However, in the above method, it is necessary to pressurize the inside of the reaction vessel with an inert gas in order to maintain the pressure at which the polymerization liquid does not boil, and the heat transfer efficiency deteriorates by cooling the gasified reaction liquid together with the inert gas. However, the problem that the cooling equipment becomes very large remains.

A method has also been proposed in which a low boiling point mercaptan is allowed to exist in the gas phase to prevent the adhesion of the polymer in the reaction tank. However, in the above method, operating conditions such as reaction temperature and reaction pressure are limited, mercaptan acts as a chain transfer agent, and the molecular weight of the polymerization product is reduced.
Since it affects the reaction, there was a problem in the quality control of the product.

[0012]

DISCLOSURE OF THE INVENTION The present invention provides a completely novel method for thoroughly suppressing the formation of an acrylonitrile-based gel component in the gas phase portion that occurs during such continuous solution or bulk polymerization.

Therefore, the present invention provides a method for easily (scaled) polymerizing (co) polymerizing a resin by easily preventing the scale from adhering to the scale in the reaction vessel without applying a scale inhibitor or the like into the reaction vessel.

Another object of the present invention is to provide a completely mixed polymerization reactor used in the above polymerization reaction.

[0015]

Means for Solving the Problems In the (co) polymerization containing an acrylonitrile-based monomer as an essential component, the present inventors have found that the formation of acrylonitrile-rich polymer causes the gelled polymer to adhere to the wall surface of the polymerization tank. As a result of studying the problem of prevention, surprisingly, by controlling the temperature of the gas phase part within a specific range in a reaction tank having a gas phase part, the above-mentioned adhesion, which has been a big problem in the past, was completely eliminated. The present invention has been achieved by finding out what is done.

That is, the present invention provides a method for (co) polymerizing a monomer containing at least an acrylonitrile-based monomer as an essential component by bulk or solution (co) polymerization in the presence of a rubbery polymer, if necessary. In the reaction tank, a gas phase portion is provided above the polymerization liquid to polymerize while evaporating the monomer at a temperature of 80 ° C. or higher, and the temperature of the gas phase portion is reduced to 30 by cooling from the outside of the wall surface of the reaction tank. It is to provide a method for producing a nitrile (co) polymer, which is characterized in that the vapor generated from the polymerization liquid is condensed at the gas phase portion and (co) polymerization is carried out by maintaining the temperature at from 65 to 65 ° C.

The present invention also provides a method for (co) polymerizing a monomer containing at least an acrylonitrile-based monomer as an essential component by bulk or solution (co) polymerization in the presence of a rubbery polymer, if necessary. In the reaction tank, a gas phase portion is provided above the polymerization liquid to polymerize while evaporating the monomer at a temperature of 80 ° C. or higher, and the temperature of the gas phase portion is reduced to 30 by cooling from the outside of the wall surface of the reaction tank. Hold at ℃ ~ 65 ℃, to condense the vapor generated from the polymerization liquid in the gas phase,
It is an object of the present invention to provide a method for producing a nitrile-based (co) polymer, which is characterized in that (co) polymerization is performed without substantially outputting vapor from the polymerization liquid to the outside of the reaction tank.

Another object of the present invention is to provide a method for producing the above-mentioned acrylonitrile (co) polymer, in which the monomer contains a styrene monomer as an essential component.

Further, according to the present invention, the reaction vessel has an outer jacket which is vertically divided into at least two parts. The temperature of the upper jacket is adjusted to be lower than the temperature of the lower jacket, and the refrigerant temperature of the upper jacket is-. The temperature of the acrylonitrile-based (co) polymer is controlled to 10 ° C. to 35 ° C. and the height of the liquid surface of the polymerization liquid in the reaction tank is controlled so that the liquid surface is in contact with the portion covered by the upper jacket. It is to provide a manufacturing method.

In the present invention, the acrylonitrile-based (co) polymer of the above-mentioned acrylonitrile-based (co) polymer occupies 20% or more of the wall surface area covered by the upper jacket in the wall surface of the reaction tank. Production method.

Another object of the present invention is to provide a method for producing the acrylonitrile-based (co) polymer, in which vapor generated from the polymerization liquid is present in the gas phase portion of the reaction tank as aggregated mist.

In the present invention, a monomer and / or solvent feed pipe is installed in the gas phase portion of the reaction tank, and the reaction is carried out such that the tip of the feed pipe is close to the reaction tank end plate or the stirring shaft. To provide a method for producing the acrylonitrile-based (co) polymer, wherein a feed amount of a monomer and / or a solvent from a feed pipe is 3 to 30% by weight of a feed amount from a main raw material supply line using a tank. is there.

In the present invention, the amount of water in the polymerization liquid is 0.5.
It is an object of the present invention to provide a method for producing an acrylonitrile-based (co) polymer according to claim 1, which uses a polymerization liquid of less than wt%.

Further, the present invention has a jacket divided into at least two, and in the wall surface, the area of the wall surface covered by the upper jacket occupies 20% or more of the area of the wall surface covered by the lower jacket. The present invention is to provide a complete mixing type polymerization reaction tank. Further, the present invention is to provide the above-mentioned completely mixed polymerization reaction tank in which the lower jacket has heating means and the upper jacket has cooling means.

Further, in the present invention, a monomer and / or solvent feed pipe is installed in the gas phase portion of the reaction tank, and the tip of the feed pipe is close to the reaction tank end plate or the stirring shaft. It is to provide a mixed-type polymerization reaction tank.

Further, the present invention is to provide the above-mentioned completely mixed polymerization reaction tank having a condenser for cooling the vapor from the inside of the reaction tank outside the reaction tank.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention,
The polymerization is carried out at a temperature of 80 ° C or higher. In the (co) polymerization of a monomer containing an acrylonitrile-based monomer according to the present invention, heat is removed in the gas phase part by cooling with a refrigerant in a jacket, so that the temperature difference with the refrigerant becomes small at 80 ° C or lower. Since the heat transfer rate is small, it is disadvantageous for stable operation of removing the heat of polymerization. When the polymerization temperature is 80 ° C or lower,
In the solution or bulk polymerization, the viscosity of the liquid becomes high, it is difficult to obtain a uniform temperature in the operation in the stirring layer, and a sufficient reaction rate cannot be obtained. Is required and becomes economically disadvantageous. The polymerization temperature is not particularly limited as long as it is 80 ° C. or higher, but preferably 85 ° C., more preferably 90 ° C. or higher. The upper limit of the reaction temperature is not particularly limited, but is preferably 180 ° C.
Or less, more preferably 160 ° C. or less. When the temperature exceeds 180 ° C, it is difficult to maintain the gas phase temperature at 65 ° C or lower as used in the present invention, and in general, the reaction rate becomes abnormally high, so that the operation tends to be unstable.

In the present invention, the temperature of the reaction tank is controlled by a heat removal system using latent heat of vaporization. Therefore, the reaction tank is not full, but has a liquid phase portion in the lower part, an upper part is a gas phase part, and volatile components are evaporated from the liquid phase part. Usually, this vaporized vapor has the same temperature as the liquid phase in vapor-liquid equilibrium, and the temperature of the vapor phase portion near the liquid phase is about the reaction temperature. In the present invention, the temperature of the gas phase part is set to 3
The temperature is adjusted to 0 ° C to 65 ° C, preferably 30 ° C to 55 ° C.
If the temperature exceeds 65 ° C, the adhesion of the polymer will rapidly increase.
In addition, it is practically difficult to operate at a gas phase temperature of 30 ° C. or lower.

The temperature of the gas phase portion in the present invention means a temperature at least 15 cm, preferably 50 cm lower in the vertical direction than the inside of the highest vertical point of the inner wall of the reaction vessel. The meaning of 15 cm is not for measuring the temperature of the inner wall itself but for measuring the temperature of the gas phase portion in the reaction tank.

On another scale, the temperature measurement position is 5 to 40% from the top of the reaction tank with respect to the height of the reaction tank.

The measurement position of the temperature of the gas phase portion of the present invention is measured at a position far from the wall surface of the reaction tank and the upper end plate so that the temperature of the jacket is not affected and the above conditions are satisfied. preferable. Further, the present inventors have discovered that the temperature of the gas phase in the vicinity of the inner wall has an important influence on the formation of deposits, and the present inventors have reached the present invention.

In the present invention, the temperature of the gas phase portion is 30 ° C. to 6 ° C.
The method of controlling the temperature at 5 ° C is by adjusting the jacket temperatures of the lower and upper parts. That is, when the temperature of the lower jacket is raised, the temperature of the gas phase portion is raised, and when it is lowered, it is lowered. The temperature of the refrigerant in the upper jacket is -10 ° C.
The temperature of the gas phase part can be controlled within the above range by controlling the temperature in the range from 35 to 35 ° C. When the refrigerant temperature of the upper jacket is 20 to 35 ° C, it is easy to control the temperature of the lower liquid phase portion, and when it is -10 to 20 ° C, the temperature of the upper gas phase portion is easily controlled, which is preferable. The flow rate of the refrigerant can be easily determined by those skilled in the art as long as the temperature of the gas phase part can be controlled to 30 ° C to 65 ° C.

As described above, the method of the present invention comprises the lower jacket for controlling the temperature of the reaction vessel and the upper jacket for cooling the gas phase.
The purpose can be achieved with one jacket, but the temperature distribution can be controlled by providing three jackets or more if necessary. In the method of the present invention, it is preferable to adjust the liquid level so that it is above the lower jacket.

In the method of the present invention, in the gas phase portion of the reaction tank, the vapor evaporated from the polymerization liquid is condensed to form a mist in a cloud-like state. Observed in the reaction phase. When such a state is observed, the amount of gas that goes out of the reaction tank decreases, which is preferable.

Further, in the present invention, the reaction tank has a jacket divided into at least two parts, and the area of the wall surface covered by the upper jacket is 20% or more of the area of the wall surface covered by the lower jacket. The reaction tank it occupies. Further, the present invention provides a completely mixed polymerization reaction tank for producing a (co) polymer, in which the lower jacket has a heating means and the upper jacket has a cooling means.

In the present invention, in addition to the polymerization raw material supply line provided in the liquid phase part, a feed pipe is preferably installed in the gas phase part in the reaction tank, and the monomer and / or the solvent is fed from the feed pipe. It is also preferable to do so, especially to atomize. It is preferable that the tip of the feed pipe is installed close to the end plate of the reaction vessel or the stirring shaft. Further, a disc may be attached to the upper part of the stirring blade, and a monomer and / or a solvent may be fed thereto to provide a dispersion plate capable of washing the wall surface in the reactor by centrifugal force.

As the monomer and / or solvent fed from the feed pipe, those used as raw materials used in the polymerization reaction are used. When the styrene-based monomer is contained as the comonomer, the styrene-based monomer is mainly used as the monomer. Preferably.

The amount of the monomer and / or solvent fed is preferably 3 to 30% by weight, more preferably 3 to 20% by weight, and more preferably 4% of the total amount of raw materials supplied to the reaction tank.
10 to 10% by weight. When it exceeds 30% by weight, the mixing with the lower polymerization solution becomes poor, which causes a problem in stability of the polymerization operation.

The feed from the main raw material supply line in the present invention means a feed from a line which supplies 70% by weight or more, preferably 80% by weight or more of the total amount of raw materials supplied to the reaction tank. Although this line is not particularly limited, it is attached to the reaction vessel, and its feed port is preferably attached so as to be directly fed into the lower polymerization liquid from the lower portion or the lateral portion of the reaction vessel.

In the present invention, it is preferable that the vapor evaporated from the lower polymerization solution to the gas phase portion is (co) polymerized without substantially leaving the vaporization reaction vessel of the present invention. Adhesion tends to occur when the substantially evaporated vapor is discharged to the outside of the reaction tank. In the present invention, operating without substantially emitting vaporized vapor outside the reaction vessel means that the total amount of vaporized vapor in the reaction vessel is 1
As 00%, it means that the amount of steam that goes out of the reaction tank is preferably 2% or less, more preferably 1% or less, and particularly preferably 0.5% or less.

However, in order to cope with a change in the condition of the reaction tank or an abnormal rise in temperature, it is necessary to discharge the steam out of the reaction tank within a short time, for example, one hour within 24 hours of operation. However, it is included in the present invention.

The point of the present invention is to set the temperature of the gas phase portion to 30
Is to control the temperature to ~ 65 ° C
Substantially most of the total operating time of (co) polymerization, preferably 80% or more, more preferably 90% or more, must be (co) polymerized within the above temperature range. Therefore, in the above-mentioned unsteady operation, the time for discharging the steam out of the reaction tank is also limited.

Particularly in the case of a reaction having a large calorific value, a condenser for condensing the vapor discharged outside the reaction vessel is used as a reaction vessel under the condition that the vapor is sufficiently condensed in the gas phase portion of the reaction vessel of the present invention. The external installation does not hinder the present invention.

In the wall surface of the reaction tank, the area of the wall surface covered by the upper jacket is 20% to 300%, preferably 30% or more of the area of the wall surface covered by the lower jacket.
It is more preferably 50% or more, and particularly preferably 80% or more. This is because, in the present invention, the vapor evaporated from the lower polymerization liquid is condensed in the upper jacket and is necessary for its condensation and cooling.

In the present invention, the temperature of the cooling medium in the upper jacket can be appropriately selected because the temperature of the upper gas phase portion may be within the range specified in the present invention, but it is in the range of -10 to 35 ° C, preferably 0 to 35 ° C. 30 ° C, more preferably 10-30
° C.

In the (co) polymerization of the present invention, the polymerization liquid accounts for 30 to 80%, preferably 40 to 70% of the total volume of the reactor.

In the case of the present invention, water may be present in the polymerization liquid, but it is preferable that the amount is smaller than 0.5%, particularly preferably 0.1% or less. When 0.5% or more of water is mixed, the pressure of the vapor phase portion is affected by the vapor pressure of water, and therefore the temperature of the vapor phase portion fluctuates, which is not preferable for continuing stable operation.

As described above, by controlling the temperature of the gas phase portion in the reaction tank within a specific range, the heat of reaction is effectively removed and gel adhesion on the inner wall of the reaction tank can be prevented.

Examples of the acrylonitrile-based monomer of the present invention include acrylonitrile, methacrylonitrile, ethacrylonitrile and fumaronitrile, and acrylonitrile and a mixture thereof are preferably used.

Although it is essential that the method of the present invention contains an acrylonitrile-based monomer, the method of the present invention is also preferably used for copolymerization with other monomers. In particular, the method of the present invention is preferably used for a copolymer of an acrylonitrile monomer and a styrene monomer.

Examples of the styrene-based monomer used in the present invention include styrene, α-alkylmonovinylidene aromatic monomers (for example, α-methylstyrene; α-ethylstyrene; α-methylvinyltoluene; α-methyldialkylstyrene). ;, Etc.), ring-substituted alkylstyrene (eg o
-M- and p-vinyltoluene; o-ethylstyrene;
p-ethylstyrene; 2,4-dimethylstyrene; p-
Etc.), ring-substituted halostyrenes (eg o-chlorostyrene; p-chlorostyrene; o
-Bromostyrene; 2,4-dichlorostyrene; etc.), ring-alkyl, ring-halo substituted styrenes (eg 2
-Chloro-4-methylstyrene; 2,6-dichlorostyrene; etc.) vinyl naphthalene, vinyl anthracene, or a mixture thereof. Generally alkyl substituents have 1 to 4 carbon atoms and include isopropyl and isobutyl groups. One or a mixture of these monovinylidene aromatic monomers is used.

The monomer copolymerizable with the acrylonitrile monomer and / or the styrene monomer is not particularly limited, but acrylates such as methyl methacrylate, acid anhydrides such as maleic anhydride, N- Examples include maleimides such as phenylmaleimide and cyclohexylmaleimide.

When the copolymer is produced by the method of the present invention, the acrylonitrile-based monomer is preferably 5 to 80% by weight, more preferably 5 to 60% by weight, and the styrene-based monomer is based on all the monomers. The monomer is preferably 5-95% by weight, more preferably 20-95% by weight, most preferably 40-95% by weight.
It is 95% by weight.

Further, depending on the target copolymer, preferably 0 to 30% by weight, more preferably 0 to 15% by weight, based on the total amount of acrylonitrile-based monomers and / or styrene-based monomers. It may be replaced with another monomer.

In the present invention, when the rubber-like polymer is required, the rubber-like polymer is not particularly limited as long as it exhibits a rubbery state at room temperature, but preferably conjugated 1,3-diene is used. (For example, butadiene; isoprene; etc.) and other polymers such as polybutadiene and styrene
Examples thereof include butadiene copolymer and EPDM (ethylene-propylene-diene methylene linkage).

At this time, the rubber-like polymer may be used in an amount of preferably 4 to 50 parts by weight, more preferably 4 to 20 parts by weight, based on 100 parts by weight of all monomers for polymerization.

In the method of the present invention, a solvent may be used, and examples thereof include benzene, toluene, xylene, ethylbenzene, acetone, isopropylbenzene and methylethylketone, and the use of toluene and ethylbenzene is particularly preferable. The amount of solvent used is 100 monomers used
Preferably 5 to 50 parts by weight, more preferably 1
It is 0 to 30 parts by weight.

The method of the present invention does not necessarily require an initiator, but an initiator can also be used. The initiator is preferably t-butylperoxypivalate, t-
Butyl peroxy (2-ethyl hexaate), 1,1
-Bis (t-butylperoxy) 3,3,5-trimethylcyclohexane is exemplified, and particularly preferably t-butylperoxy (2-ethylhexaate), 1,1-bis (t-butylperoxy) 3. It is 3,3,5-trimethylcyclohexane. The initiator is preferably 0.001 to 5.0 parts by weight, more preferably 0.001 to 3.5 parts by weight, and particularly preferably 0.001 part by weight, relative to 100 parts by weight of the monomers as the polymerization raw material.
001 to 2.0 parts by weight.

The jacket attached to the reaction vessel used in the present invention is a device attached to the vessel wall for heating or cooling from the outside through the wall of the reaction vessel in order to control the temperature of the contents in the reaction vessel or the like, Usually, a space in which a heat transfer medium can flow through is provided outside the reaction tank. There are various other shapes depending on the application.

[0060]

The present invention will be described in more detail with reference to the following examples. The present invention is not limited to these examples. The performance evaluation was measured according to the following criteria.

Measurement of Fish Eye Number The obtained product was extruded to a thickness of 0.1 mm and the area was 50
The number of fish eyes having an area of 0.02 mm ² or more existing per 00 cm ² was measured.

Example 1 The first and second complete mixing type polymerization reaction tanks used in this example had a volume of 80 liters and two monomer feed pipes.
One tip is at a position 10 mm away from the reaction tank end plate, and the other is at a position 20 mm away from the stirring shaft (a position 20% of the height from the top of the reaction tank). In addition, a reaction tank was used in which the area of the upper jacket was 233% of the area of the lower jacket. The polymerization liquid is 38 in both reaction tanks.
Copolymerization was carried out in the presence of liter (47.5% of the total volume).

Styrene 74.5 parts by weight, acrylonitrile 25.5 parts by weight, ethylbenzene 25 parts by weight, rubber-like polymer (butadiene polymer solution viscosity 30 cst 5%
Styrene solution 25 ° C.) 10 parts by weight, organic peroxide [1,1-bis (t-butylperoxy) 3,3,5-
Trimethylcyclohexane] 0.035 parts by weight and mercaptan 0.15 parts by weight as raw material liquids were added to the first reaction tank.
It was continuously fed at 8 liter / hr. At that time, the temperature of the lower jacket was controlled so that the polymerization temperature was 100 ° C. The temperature of the gas phase was 52 ° C., water of 30 ° C. was passed through the upper jacket, and the liquid level was controlled so as to come into contact with the position covered by the upper jacket at a height of 50 mm.

Separately from the main raw material feed line, styrene monomer was supplied in an amount of 5 wt% of the total raw material feed by atomizing it from a monomer feed pipe installed in the gas phase part.

The pressure inside the first reaction tank was adjusted to 0.64 kg / cm ² . The obtained reaction liquid was further supplied to the second reaction tank to promote polymerization. The internal pressure of the second reaction tank is 1.
2 kg / cm ² , the polymerization temperature was 120 ° C., the monomer was not fed, and water of 20 ° C. was passed through the upper jacket to carry out the polymerization so that the temperature of the gas phase was 55 ° C.
When the inside of the reaction tank was inspected after 6 months of operation, the first reaction tank,
No gel adhered in the second reaction tank. Further, no fish eyes of the obtained product were observed.

Example 2 Operation was carried out under the same conditions as in Example 1 except that water at 10 ° C. was passed through the upper jacket of the first reaction tank. The temperature of the vapor phase portion became 35 ° C. Upon inspection after 6 months, no gel was observed and no fish eyes of the obtained product were observed.

Comparative Example 1 Copolymerization was carried out under the same conditions as in Example 1 except that hot water at 70 ° C. was passed through the upper jacket of the first reaction tank. The temperature of the gas phase in the reaction tank was 82 ° C. After running for 1 week, gel was generated in the reaction reactor. The number of fish eyes was 367.

Comparative Example 2 Copolymerization was carried out under the same conditions as in Example 1 except that hot water at 40 ° C. was passed through the upper jacket of the first reaction tank. The temperature of the gas phase in the reaction tank was 79 ° C. After running for 1 week, gel was generated in the reaction reactor. The number of fish eyes was 132.

Example 3 The reaction vessel used in this example had a volume of 80 liters, two monomer feed tubes, one tip was 10 mm away from the upper end plate of the reaction vessel, and the other was stirred. 20 mm away from the axis (20 from the top of the reaction tank
%), And the area of the upper jacket was 233% of the area of the lower jacket. A reactor was used to copolymerize styrene and acrylonitol. .
The polymerization liquid was added to the reaction tank at 38 liters (total volume of 47.5
%) And the polymerization was carried out.

60 parts by weight of styrene, acrylonitrile 2
Using 0 parts by weight, 20 parts by weight of ethylbenzene, and 0.2 parts by weight of mercaptan as raw materials, 38 liters /
It was continuously fed for hr. At that time, the lower jacket temperature was controlled so that the polymerization temperature was 140 ° C.
The temperature of the gas phase was 57 ° C., water of 15 ° C. was passed through the upper jacket, and the liquid surface was controlled so as to come into contact with the position covered by the upper jacket at a height of 50 mm.

Separately from the main raw material feed line, styrene monomer corresponding to 5% by weight of the total raw material feed was atomized and supplied from a monomer feed pipe installed in the gas phase part.

The inside of the reaction tank was adjusted to a pressure of 0.43 kg / cm ² . When the inside of the reaction tank was inspected after the operation for 3 months, no gel adhered to the inside of the reaction tank. Further, no fish eyes of the obtained product were observed.

[0073]

According to the method of the present invention, by cooling the gas phase part of the reaction tank and maintaining it at a specific temperature, the polymerization of unreacted monomers in the gas phase part is suppressed, and the gelled polymer is mixed in the product. Without doing so, the heat of reaction during polymerization can be efficiently removed.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akihiko Nakajima 1-6 Takasago, Takaishi, Osaka Prefecture Mitsui Toatsu Kagaku Co., Ltd. (72) Masato Takahisa 1-6 Takasago, Takaishi, Osaka Mitsui Toatsu Kagaku Co., Ltd. (72) Inventor Nao Morita 1-6 Takasago, Takaishi-shi, Osaka Mitsui Toatsu Chemical Co., Ltd.

Claims (9)

[Claims] 1. A (co) polymer by bulk or solution (co) polymerization of a monomer containing at least an acrylonitrile monomer as an essential component, if necessary in the presence of a rubbery polymer.
In the polymerization method, a gas phase portion is provided above the polymerization liquid in the reaction tank to polymerize while evaporating the monomer at a temperature of 80 ° C. or higher, and the gas phase portion is cooled from the outside of the wall surface of the reaction tank. The method for producing a nitrile-based (co) polymer, characterized in that the vapor generated from the polymerization liquid is condensed in the gas phase and (co) polymerization is carried out while maintaining the temperature of 30 to 65 ° C. 2. The method for producing an acrylonitrile (co) polymer according to claim 1, wherein the monomer further contains a styrene monomer as an essential component. 3. The reaction tank has a jacket which is vertically divided into at least two parts, the temperature of the upper jacket is adjusted to be lower than the temperature of the lower jacket, and the temperature of the refrigerant in the upper jacket is -10.degree. The acrylonitrile-based (co) polymer according to claim 1, wherein the height of the liquid level is controlled so that the liquid level of the polymerization liquid in the reaction vessel is controlled at 35 ° C. and is in contact with the portion covered by the upper jacket. Manufacturing method. 4. The method for producing an acrylonitrile (co) polymer according to claim 1, wherein the vapor generated from the polymerization liquid is present in the gas phase portion of the reaction tank as aggregated mist. 5. The acrylonitrile (co) polymer according to claim 3, wherein the area of the wall surface covered with the upper jacket occupies 20% or more of the surface area of the wall surface covered with the lower jacket in the wall surface of the reaction tank. Production method. 6. A reaction vessel in which a feed tube for a monomer and / or a solvent is installed in a gas phase portion in the reaction vessel, and a tip of the feed tube is close to the reaction vessel end plate portion or the stirring shaft is used. , The feed amount of the monomer and / or solvent from the feed pipe is 3 times the feed amount from the main raw material supply line.
The method for producing an acrylonitrile-based (co) polymer according to claim 1, wherein the amount is ˜30% by weight. 7. A wall surface having a jacket divided into at least two parts, wherein the wall surface area covered by the upper jacket is 20 times the wall surface area covered by the lower jacket.
A fully mixed polymerization reaction tank that accounts for more than 100%. 8. The completely mixed polymerization reaction tank according to claim 7, wherein the lower jacket has a heating means and the upper jacket has a cooling means. 9. A monomer and / or solvent feed pipe is installed in the gas phase of the reaction tank, and the tip of the feed pipe is close to the end plate of the reaction tank or the stirring shaft.
The completely mixed polymerization reactor described.