JP3506323B2 - Method for producing copolymer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous process for producing an aromatic vinyl-vinyl cyanide-based copolymer, which reduces the formation of polymer scale and polymer blocks in a polymerization apparatus and allows gels to be incorporated into products. TECHNICAL FIELD The present invention relates to a production method capable of reducing long-term polymer mixture and enabling continuous operation for a long time while maintaining high productivity.

[0002]

2. Description of the Related Art A polymer scale or polymer block produced in a polymerization apparatus when an aromatic vinyl-vinyl cyanide copolymer is produced has a reduced heat transfer capacity, a reduced effective cross-sectional area of a pipe, and a corresponding pressure. It causes various problems such as increased loss, plugging, and marked deterioration of product appearance and mechanical properties due to inclusion of gel polymer in the product. Then, when polymer scales and polymer blocks are formed, it is necessary to temporarily stop the operation and remove them, which causes a large decrease in productivity.

Conventionally, as a method for preventing the formation of polymer scale in a polymerization apparatus, for example, JP-A-57-253 has been used.
No. 10, a method of controlling the water content contained in the raw material, a method of adding an amide compound and polymerizing as in JP-A-60-260605 have been proposed.
In these methods, the dehydration operation and the composition control of the recovery solvent containing the monomer are complicated, and the problems such as the deterioration of various physical properties such as optical properties accompanying the incorporation of the amide compound into the product remain.

Japanese Patent Publication No. 7-5644 discloses a method of connecting two or more polymerization vessels and controlling the polymerization conversion rate at the outlet of the first polymerization vessel to prevent the formation of gel polymer. Although proposed, this method complicates the device,
The problem remains that production control including temperature control is difficult.

Further, in Japanese Patent Laid-Open No. 9-77806,
A method of wetting the vessel wall by spraying the raw material onto the vapor phase vessel wall above the polymerization vessel has also been proposed, but this method has the problem that a gel polymer is likely to be generated in places where the spray liquid does not directly come into contact and in the piping. .

Further, Japanese Patent Laid-Open No. 5-255448 proposes a method of keeping the inside of each polymerization vessel within 120 to 150 ° C. and the polymerization conversion rate of monomers within 30% / hr. However, this method is not always sufficient in productivity.

[0007]

The object of the present invention is to continuously produce an aromatic vinyl-vinyl cyanide copolymer, for example, the inner wall surface of the vapor phase part of the complete mixing tank type polymerization vessel, pipes, nozzles, etc. The production of polymer scale and polymer blocks in the product is prevented to reduce the heat transfer ability, blockage of piping, and the deterioration of product appearance and mechanical properties due to the inclusion of gel polymer in the product, resulting in high production. An object of the present invention is to provide a continuous production method of an aromatic vinyl-cyanide vinyl-based copolymer, which enables stable production for a long period of time while maintaining the properties.

[0008]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a method for continuously producing an aromatic vinyl-vinyl cyanide-based copolymer, and as a result, during the polymerization, the vapor phase vapor was extracted and cooled. , Re-spraying the condensed liquid on the gas phase part to activate the gas-liquid contact in the gas phase part to lower the temperature of the gas phase part is a remarkable effect in preventing formation of polymer scale or polymer block. Therefore, the present invention has been completed. The production method of the present invention does not disturb the monomer ratio of the polymerization liquid, and also does not disturb the monomer weight / solvent weight ratio so that there is almost no change in operation, and the secondary production is achieved. The wetting effect of the vapor phase wall is an excellent manufacturing method that helps prevent the formation of polymer scale and polymer blocks.

That is, the present invention provides a raw material mixture containing an aromatic vinyl monomer, a vinyl cyanide monomer and other vinyl monomers copolymerizable with these in the presence of a solvent. In the method for producing a copolymer which is continuously copolymerized, 50 to 80% by weight of an aromatic vinyl-based monomer, 50 to 20% by weight of a vinyl cyanide-based monomer, and other copolymerizable with these. 100 parts by weight of a monomer mixture liquid of 0 to 30% by weight of a vinyl-based monomer, 10 to 50 parts by weight of a solvent, 0 to 1 part by weight of a polymerization initiator, and 0 to 1 part by weight of a molecular weight modifier are mixed in a gas phase. A continuous mixing tank type polymerization device (I) equipped with a condenser for condensing some vapors or a polymerization device in which at least one polymerization device (I) and a polymerization device (II) connected thereto are continuously supplied. , The polymerization temperature of the polymerization vessel (I) is 120 to 1
The temperature and supply amount of the vapor condensate refluxed from the condenser of the polymerizer (I) so that the total concentration of the condensate components having a boiling point of 120 ° C. or less at atmospheric pressure is 65% by weight or more. Of the polymerization vessel (I)
The present invention relates to a continuous process for producing the copolymer, which comprises spraying the gas phase part of

The present invention will be described in detail below. The aromatic vinyl-based monomer in the present invention is a radically polymerizable compound having an aromatic group and a vinyl group in the molecule,
For example, styrene, α-methylstyrene, p-methylstyrene, 3,5-dimethylstyrene, 2,4-dimethylstyrene, alkyl group-substituted styrene such as t-butylstyrene, α-bromostyrene, p-bromostyrene, o- Examples thereof include halogenated styrene such as chlorostyrene and p-chlorostyrene. These aromatic vinyl monomers may be used alone or in combination of two or more.

The amount of the aromatic vinyl monomer used is 50 to 80% by weight, preferably 55 to 80% by weight, more preferably 60 to 80% by weight, most preferably 65 to 77, based on the total amount of the monomers. % By weight. If less than 50% by weight,
If it exceeds 80% by weight, the heat resistance and mechanical properties will deteriorate.

The vinyl cyanide monomer in the present invention is a radically polymerizable compound having a nitrile group and a vinyl group in the molecule, and examples thereof include acrylonitrile and methacrylonitrile. These vinyl cyanide-based monomers may be used alone or in combination of two or more.

The vinyl cyanide monomer is used in an amount of 50 to 20% by weight, preferably 45 to 20% by weight, and most preferably 35 to 23% by weight, based on the total amount of the monomers. When it exceeds 50% by weight, the heat discoloration resistance is deteriorated, and 20% by weight
If it is less than 1, heat resistance and mechanical properties are deteriorated.

In the present invention, the vinyl-based monomer copolymerizable with the aromatic vinyl-based monomer or the vinyl cyanide-based monomer, which can be added as necessary, is a vinyl group in the molecule. A radically polymerizable compound having, for example, methyl methacrylate, ethyl methacrylate,
(Meth) acrylic acid esters such as methyl acrylate and ethyl acrylate, unsaturated acids such as acrylic acid and methacrylic acid, unsaturated acid anhydrides such as maleic anhydride, N-methylmaleimide, N-phenylmaleimide, N- Examples thereof include maleimide-based monomers such as cyclohexylmaleimide.
These vinyl-based monomers may be used alone or in combination of two or more.

The amount of these vinyl monomers used is 30% by weight or less, preferably 10% by weight or less based on the total amount of the monomers.

The solvent used in the present invention is an inert polymerization solvent which is usually used in radical polymerization, for example, ethylbenzene, toluene, xylene, o-xylene, m-xylene, p-xylene, cumene, n-propyl. Aromatic hydrocarbons such as benzene and isopropylbenzene, ketones such as 2-butanone and methyl isobutyl ketone, N, N
Examples include amide compounds such as dimethylformamide, N, N-dimethylacetamide and N-methylpyrrolidone. Among these solvents, solvents other than aromatic hydrocarbons are preferably used in combination with aromatic hydrocarbons. For example, when 2-butanone is used alone, only a component containing a large amount of a vinyl cyanide-based polymer among the aromatic vinyl-vinyl cyanide-based copolymers that jumped by stirring during polymerization and adhered to the inner wall of the gas phase part Remain undissolved, and this easily becomes a gel polymer.

The amount of the solvent used is 10 to 50 parts by weight, preferably 17 to 45 parts by weight, and most preferably 24 to 35 parts by weight, based on 100 parts by weight of the monomer mixture. If the amount is less than 10 parts by weight, the viscosity of the polymerization liquid in the complete mixing tank type polymerization vessel becomes high, the required power required for stirring becomes too large, and heat removal failure due to poor mixing occurs and temperature control becomes difficult, Moreover, the production of polymer scales and polymer blocks increases. On the other hand, if it exceeds 50 parts by weight,
The load on the devolatilization preheater increases, the production efficiency decreases, and the molecular weight also decreases, so that the mechanical properties required for an aromatic vinyl-vinyl cyanide copolymer or an ABS resin using the same cannot be obtained. In addition, the required flow characteristics cannot be obtained.

In the present invention, known polymerization initiators can be used as the polymerization initiator to be added as required. For example, ketone peroxides such as methyl ethyl ketone peroxide, 1,1-bis (t-butylperoxy). 3,3
5-trimethylcyclohexane, 2,2-bis (4,4
-Peroxyketals such as di-t-butylperoxycyclohexyl) propane, hydroperoxides such as cumene hydroperoxide, dialkyl peroxides such as dicumyl peroxide, diacyl peroxides such as benzoyl peroxide, Peroxydicarbonates such as diisopropyl peroxydicarbonate, peroxyesters such as t-butyl peroxyisopropyl carbonate, 2,2′-azobisisobutyronitrile, 1,1′-azobis (cyclohexane-1- Azonitriles such as carbonitrile), t-
Examples thereof include butyl peroxyallyl carbonate, t-butyl trimethyl silyl peroxide, and organic peroxides such as 3,3 ′, 4,4′-tetra (t-butyl peroxy carbonyl) benzophenone. Among these polymerization initiators, those having a temperature showing a 10-hour half-life of 60 to 120 ° C. are particularly preferable. These polymerization initiators may be used alone or in combination of two or more.

It is advantageous that the amount of the polymerization initiator used is large so that the reaction rate can be increased so long as the removal of the reaction heat in the polymerization apparatus can be controlled. The practical amount used is 0 to 1 part by weight, preferably more than 0 and 1 part by weight, based on 100 parts by weight of the total amount of the monomers.

In the present invention, the molecular weight regulator added as necessary is a molecular weight regulator usually used in radical polymerization, and is a linear chain such as n-dodecyl mercaptan, t-dodecyl mercaptan or cyclohexyl mercaptan.
Alkyl mercaptans having a branched or cyclic structure,
Mercaptans having an unsaturated bond such as butenyl mercaptan, polyvalent thiols such as 1,2-ethanedithiol,
Aromatic thiols such as thiophenol and 2-mercaptotoluene, mercaptans having a hydroxy group such as 1,3-dimercapto-2-propanol, and dodecyl 3-
Mercaptans having an ester group such as mercaptopropionate, terpenes such as 1-methyl-4-isopropylidenylcyclohexane, 2,4-diphenyl-4-
Methyl-1-pentene and the like can be mentioned. These molecular weight modifiers may be used alone or in combination of two or more.

The total amount of the monomers used is 1
The amount is 1 part by weight or less, preferably more than 0 and 1 part by weight or less, and more preferably 0.01 to 0.5 part by weight, relative to 00 parts by weight. When the amount exceeds 1 part by weight, the molecular weight of the product aromatic vinyl-cyanide-based copolymer becomes too small. Particularly, the aromatic vinyl-vinyl cyanide-based copolymer is used as a raw material for the ABS resin. At this time, the strength of the ABS resin decreases.

The polymerization apparatus used in the present invention is a complete mixing tank type polymerization vessel (I) equipped with a condenser for condensing vapor in the gas phase, or the polymerization vessel (I) and a polymerization vessel (II) connected thereto. Consists of one or more units. As the polymerization vessel (II), a complete mixing tank type polymerization vessel, a tube type polymerization vessel, an extruder type polymerization vessel, a kneader type polymerization vessel or the like can be used.

The embodiment for making the polymerization liquid in the polymerization vessel (I) substantially uniform is not particularly limited,
Ribbon type stirring blades such as helical ribbon blades, turbine type stirring blades, screw type stirring blades, anchor blades, paddle blades such as inclined paddle blades and flat paddle blades, full zone blades (trade name), Maxblend blades (trade name), Alternatively, in addition to stirring and mixing with a sun-merer blade (trade name) or the like, circulation mixing with a pump or the like provided outside the polymerization vessel (I) may be combined therewith.

When the polymerization vessel (I) is agitated and mixed, a lower agitation system in which a stirring blade driving section is provided at the bottom of the polymerization vessel is excellent in order to prevent the adhesion of the polymer to the agitation shaft in the gas phase section.

In the present invention, the temperature of the outer portion of the wall of the polymerization vessel which is in contact with the gas phase portion of the polymerization vessel (I) (hereinafter, "outside temperature" of the gas phase portion)
Is preferably lower than the temperature of the vapor phase part.
The outside temperature of the gas phase is 0 to 120 ° C, preferably 0 to 100 ° C,
More preferably 20 to 100 ° C., most preferably 60.
~ 80 ° C. If the temperature is lower than 0 ° C, the polymer solution that jumps up at the time of stirring and adheres to the surface of the inner wall of the gas phase portion becomes too viscous, and stays for a long time to form a gel-like polymer. It may cause contamination. On the other hand, when the temperature exceeds 120 ° C, the vapor generated from the polymerization liquid is polymerized while condensing on the inner wall surface of the gas phase portion to form a gel-like polymer, which is mixed in the polymerization liquid and mixed with the gel-like polymer in the product. Cause.

A general method for lowering the outside temperature of the gas phase portion of the polymerization vessel (I) below the temperature of the gas phase portion is to pass cold water or a refrigerant through a jacket provided outside the polymerization vessel wall. A method of sprinkling water on the polymerization vessel without providing a jacket may be used, and a known method can be appropriately adopted. When the jacket is provided in the polymerization vessel (I), it is most preferable that the jacket is divided into the gas phase portion and the liquid phase portion, and the temperature can be controlled independently for each of the gas phase portion and the liquid phase portion. In the present invention, the external temperature of the gas phase part is as described above, but it is difficult to directly measure the temperature in the case of the polymerization vessel (I) with an overcoat, and therefore, for convenience, the inlet and outlet of the overcoat are used. The arithmetic mean value of the temperature of the refrigerant (heating medium) in.

The vapor condensate in the present invention is a condensate obtained by condensing the vapor generated in the polymerization vessel (I) with a condenser connected to the polymerization vessel (I) directly or via a gas pipe. Examples of the condenser to be used include a spray condenser and a shell & tube condenser. The vapor condensate has a boiling point of 120 ° C. or less at atmospheric pressure, preferably 100 ° C. or less, more preferably 90% or less, and the total concentration of the components is 65% by weight or more, preferably 65 to 95% by weight, and further It is preferably adjusted to 70 to 90% by weight. If the total concentration of the components having a boiling point of 120 ° C. or less at atmospheric pressure is less than 65% by weight, the gas phase temperature of the polymerization vessel (I) becomes too high, and the nozzle or pipe connected to the polymerization vessel (I) may have The condensed condensate is polymerized into a gelled polymer, which is mixed in the polymerized liquid and causes gelled polymer to be mixed in the product.

As the component having a boiling point of 120 ° C. or less at atmospheric pressure, for example, vinyl cyanide-based monomers having a boiling point in this range, toluene solvent and the like are applicable. Vinyl cyanide-based monomers are preferred because of their high solubility in polymers, and acrylonitrile is a particularly preferred component.

The boiling point of the vapor condensate at atmospheric pressure is 12
As a method for adjusting the total concentration of components having a temperature of 0 ° C. or lower, for example, the temperature and supply amount of the vapor condensate sprayed on the gas phase part of the polymerization vessel (I) are adjusted.

The temperature of the vapor condensate sprayed on the gas phase of the polymerizer (I) is controlled by, for example, adjusting the refrigerant flow rate or the refrigerant temperature of the condenser connected to the polymerizer (I). Further, it is preferable that the supply amount of the vapor condensate sprayed to the gas phase part of the polymerizer (I) is adjusted by using a control valve or the like, and the surplus vapor condensate is directly returned to the liquid phase part of the polymerizer. In addition, the spray flow rate is stabilized, the total concentration of components having a boiling point of less than 120 ° C. at atmospheric pressure in the vapor condensate is maintained at 65 wt% or more, and the vapor condensate polymerizes in the nozzle when the flow rate decreases. In order to prevent the spray nozzle from being blocked, it is preferable to return the vapor condensate condensed by the condenser connected to the polymerizer (I) to the polymerizer (I) via the buffer tank. that time,
If necessary, the vapor condensate may be returned from the buffer tank to the polymerization vessel (I) using a pump or the like. When the total concentration of the components in the vapor condensate having a boiling point of 120 ° C. or less at atmospheric pressure is less than 65% by weight, the vinyl cyanide-based monomer in the raw material is mixed with the vapor condensate. When the concentration is adjusted to 65% by weight or more and the composition is sprayed on the gas phase part of the polymerization vessel (I), composition unevenness occurs in the produced aromatic vinyl-vinyl cyanide copolymer, resulting in loss of transparency. It is not preferable.

When a polymerizer equipped with a condenser is used as the polymerizer (II), the vapor condensate condensed by the condenser connected to the polymerizer (I) is condensed by the vapor condensate condensed by the condenser connected to the polymerizer (II). The liquids may be combined and then distributed and returned to the polymerization vessel (I) and the polymerization vessel (II). However, it is preferable that the monomer weight / solvent weight ratio in the polymerization vessel (I) is not largely changed.

The type of spray nozzle used in the present invention may be, for example, a full-cone nozzle, an empty-cone nozzle or a fan-shaped nozzle. The proper hole diameter of the spray nozzle varies depending on the number of nozzles, the flow rate of the spray liquid, the size of the polymerization vessel (I), etc., and is not unconditionally determined, but can be determined experimentally in consideration of these. The spray is applied to the vapor phase. Finer droplets are preferable in order to actively generate heat exchange between gas and liquid by spraying.
The spray is directed to the inner wall of the vapor phase portion of the polymerizer (I), the spray pipe, the stirring blade, and the like. It is preferable that the spray liquid is sprayed on these, in order to prevent the formation of polymer scale and polymer block, but the effect of wetting by spraying is secondary and is not necessarily limited to this. Also,
A spray directed to the surface of the polymer solution may be added.

In the present invention, the liquid to be supplied to the polymerization vessel (I) is the raw material solution itself mainly composed of the monomer, or the polymerization vessel (I).
In the polymerization apparatus in which I) is connected to the previous stage of the polymerization vessel (I), the monomer is partially prepolymerized in the polymerization vessel (II), but the polymerization conversion rate of the supply fluid is supplied. The amount is preferably 30% by weight or less, more preferably 10% by weight or less, and most preferably 0% by weight, based on the weight of the monomer.
If this content exceeds 30% by weight, the amount of heat of polymerization generated in the polymerization vessel (I) is limited, and the amount of evaporation in the polymerization vessel (I) becomes insufficient, so that the vapor condensate used for spraying may not be sufficiently secured.

In the present invention, the polymerization conversion rate in the polymerization vessel (I) is 30% by weight / h based on the weight of the monomer fed.
The polymerization conversion rate exceeds r. The polymerization conversion rate at the outlet of the polymerization vessel (I) is preferably 50 to 90% by weight, more preferably 60 to 90% by weight, and most preferably 70 to 90% by weight. Polymerization conversion rate is 3
When the content is 0% by weight / hr or less or the polymerization conversion rate is less than 50% by weight, the amount of heat of polymerization generated in the polymerization vessel (I) is limited and the amount of evaporation in the polymerization vessel (I) is insufficient, which is used for spraying. Not only will it not be possible to secure sufficient vapor condensate,
It also causes a decline in production capacity. The polymerization conversion rate is mainly controlled by the amount of the polymerization initiator at a predetermined polymerization temperature.

In the present invention, the polymerization temperature in the polymerization vessel (I) is 120 to 170 ° C, preferably 125 to 160 ° C, more preferably 130 to 155 ° C. In this temperature range, it is easy to secure a predetermined spray flow rate, and 30 wt% /
It is easy to achieve a polymerization conversion rate of at least hr.

The polymerization conversion rate (unit:% by weight / hr) in the polymerization vessel (I) in the present invention means the increment of the polymerization conversion rate (unit:% by weight) in the polymerization vessel (I).
Is a value obtained by dividing by the residence time (unit: hr) in the polymerization vessel (I). The residence time is the polymerization vessel (I).
It is a value obtained by dividing the volume (unit: m ³ ) of the liquid phase part of the above by the supply rate (unit: m ³ / hr) of the raw material liquid.

The polymerization conversion rate was specifically determined by measuring as follows. About 2 g of the polymerization liquid or the feed liquid was precisely weighed, diluted with acetone to 30 ml, poured into 450 ml of methanol with stirring, and the deposited precipitate was separated by filtration and dried at 80 ° C. for 4 hours under normal pressure. After that, the weight was precisely weighed. Then, the measured value of the weight of the precipitate was divided by the measured value of the weight of the polymerization liquid before being diluted with acetone, and multiplied by 100% by weight to calculate the resin concentration of the polymerization liquid. This value was divided by the concentration of the charged monomer in the raw material supplied to the polymerization apparatus to determine each polymerization conversion rate.

In the present invention, the finally discharged polymerization liquid has a polymerization conversion rate of 65% by weight or more, preferably 70% by weight.
As described above, more preferably, the content is raised to a level exceeding 80% by weight to complete the polymerization, and then the solvent and the unreacted monomer are separated and removed to obtain a copolymer. The embodiment of separation / removal in the present invention is not particularly limited, but for example, the liquid after polymerization is passed through a heat exchanger to be preheated and introduced into a tank kept under reduced pressure to remove solvent and unreacted unit amount. Examples include a method of vaporizing the body to separate and remove it.

When the copolymer is obtained from the finally discharged polymerization liquid, it is before the operation of separating and removing the solvent and unreacted monomer, or during the operation, or after the operation. At the stage, oxidation stabilizers such as phenol type and phosphorus type, light stabilizers such as benzotriazole type and hindered amine type, lubricants such as stearyl alcohol and ethylene bis stearoamide, bluing agents such as anthraquinone type, and other additions The agents can also be mixed.

Hereinafter, the present invention will be described in more detail based on an example of a polymerization apparatus shown in the drawings. FIG. 1 is a conceptual diagram showing an example of a polymerization apparatus used for carrying out the present invention. Reference numeral 1 is a polymerization vessel (I), and a baffle plate may be attached to the inner wall of the liquid phase portion to improve mixing, and 2 is a raw material or a polymerization fluid and an excess vapor condensate are supplied to the polymerization vessel (I). A liquid supply line for spraying, 3 is a spray in the vapor phase part of the polymerizer (I), 4 is a spray liquid supply line for supplying a vapor condensate to the spray, 5 is a flow meter of the vapor condensate to be sprayed, 6 Is a control valve for adjusting the flow rate of the vapor condensate to be sprayed, 7 is a check valve for preventing the raw material from being mixed in the spray, 8 is a vapor line for guiding the vapor in the vapor phase to the condenser, and 9 is vapor. A condenser for condensing the vapor condensate into a vapor condensate, 10 is a vapor condensate buffer tank, 11 is a vapor condensate extraction pump for extracting the vapor condensate from the buffer tank, and 12 is a buffer tank fluid. Meter, 13 a control valve for keeping the liquid level in the buffer tank constant, 14 a buffer tank of liquid temperature meter, 15 the polymerization solution surface, 16 the gas phase,
17 is a liquid phase part, 18 is a jacket division position, 19 is a gas phase part jacket, 20 is a liquid phase part jacket, 21 is a stirring blade, 22 is a stirrer motor, 23 is a gas phase thermometer, 2
4 is a pressure gauge with a nozzle size of 15A, 25 is a pressure gauge with a nozzle size of 50A, 26 is a polymerization liquid extraction pump for extracting the polymerization liquid, and 27 and 28 are stop valves.

The vapor in the vapor phase section 16 of the polymerization vessel (I) 1 in which the thermometer 23 and the pressure gauge 24 are installed enters the condenser 9 via the vapor line 8 and is condensed there to become a vapor condensate. This vapor condensate is temporarily stored in the buffer tank 10 in which the liquid thermometer 14 is installed, and returned to the polymerizer (I) 1 by the vapor condensate extraction pump 11,
The amount to be returned is adjusted by the combination of the liquid level gauge 12 and the control valve 13 so that the liquid level in the buffer tank 10 becomes constant. The vapor condensate discharged from the vapor condensate extraction pump 13 is sprayed from the spray 3 to the gas phase portion 16 of the polymerizer (I) 1 via the spray liquid supply line 4, and the sprayed amount is the flow rate. It is adjusted by the combination of the total 5 and the control valve 6. The polymerizer (I) 1 has a jacket, and the jacket is divided by a jacket dividing position 18 aligned with the position of the liquid surface 15 which is the interface between the gas phase portion 16 and the liquid phase portion 17. Phase jacket 19 and Liquid phase jacket 2
It consists of zero. Stirring of the polymerizer (I) 1 is performed by rotation of the stirring blade 21 by a stirrer motor 22 installed in the lower part thereof. The polymerization liquid polymerized in the polymerization vessel (I) is extracted by the polymerization liquid extraction pump 26.

The vapor phase temperature of the vapor phase section 16 of the polymerizer (I) 1 is measured by a thermometer 23. In order to adjust the vapor phase temperature, a combination of a flow meter 5 and a control valve 6 is used. Liquid thermometer 14 by adjusting the value to be set to adjust the amount of vapor condensate sprayed, or by adjusting the refrigerant flow rate and the refrigerant temperature of the condenser 9.
And a method of adjusting the temperature of the vapor condensate measured in 1. By these adjustments, the vapor-liquid equilibrium state between the vapor and the sprayed vapor condensate in the vapor phase section 16 of the polymerizer (I) 1 is adjusted, and the vinyl cyanide-based monomer in the vapor condensate is adjusted. Is adjusted, and the gas phase temperature measured by the thermometer 23 is also adjusted. By adjusting the temperature of the vapor phase portion, formation of deposits due to thermal polymerization of monomers such as vinyl cyanide-based monomers and aromatic-based monomers is prevented.

Further, due to this vapor-liquid equilibrium, the superheated vapor immediately after evaporating from the liquid surface 15 becomes saturated vapor due to the spray of the vapor condensate, and not only the vapor phase jacket 19 but also the thermometer 23 and the pressure gauge 24 are sprayed. Condensation will begin to occur even on the parts that are not directly applied, and the condensate will have the effect of washing off various vessel walls. As a result, not only the direct cleaning by spraying but also the cleaning of the non-sprayed part occurs.

[0044]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples. First, the analysis or evaluation method used in the present invention will be described.

Composition analyzer for vapor condensate: Gas chromatograph GC-8AIF (manufactured by Shimadzu Corporation) Column: PEG20M + TCEP (15 + 5% / UNIPOR)
TB60 / 80M), SUS3φmm × 3m, temperature 115 ° C, carrier flow rate 30ml / min Detector: FID Evaluation of foreign matter Check the presence of foreign matter such as gel polymer or opaque resin in the manufactured copolymer. , 100 g of a copolymer pellet having a length of about 3 mm and a diameter of about 3 mm was randomly sampled, and each pellet was individually observed as a specimen by visual observation. Next, length 4 cm x 4 cm x thickness 1 mm, 2 m
Five three-stage plates composed of three parts of m and 3 mm were molded to obtain a sample, and the presence or absence of foreign matter contained in the sample was visually observed. In each case, when no foreign matter was found in the sample, it was evaluated as “no foreign matter”.

Example 1 A polymerization apparatus having a structure shown in FIG. 1 with a total capacity of 438 liters and a liquid phase capacity of 190 liters was used with a stirring blade as a Maxblend blade. The polymerization apparatus consisted of the polymerization vessel (I) 1 shown in FIG. 1. The polymerization solution obtained by supplying the raw materials to the polymerization apparatus and polymerizing under the conditions shown in Table 1 was extracted by the polymerization solution extraction pump 26. After that, the temperature was raised to 230 ° C. in a multi-tube heat exchanger and then flushed in a tank whose pressure was reduced to 4 kPa in absolute pressure to separate and remove the solvent and unreacted monomers to produce a copolymer. 5 under the conditions shown in Table 1.
When the copolymer was continuously produced for a day and sampled every other day for observation and evaluation, no foreign matter such as gel polymer or opaque resin was found in the produced copolymer. It was Further, after completion of the production for 5 days, the polymerization vessel (I) 1 was opened and inspected without washing, and the gas phase portion 16
No deposits such as resin were found on the nozzle of the thermometer 23, the nozzle of the pressure gauge 24, the vapor line 8 and the like, in addition to the vessel wall. The obtained operation results are summarized in Table 1. (The same applies to the following examples and comparative examples).

Example 2 A polymerization vessel (I) shown in FIG. 1 having two polymerization vessels and a jacket at the rear stage of the polymerization vessel (I) 1 and having a volume of 140 liters was a liquid-filled complete mixing tank type polymerization vessel (II). ) Was installed. The polymerization solution obtained by supplying the raw materials to this polymerization apparatus is withdrawn by the polymerization solution withdrawing pump 26 shown in FIG. 1 and then further polymerized in the polymerization vessel (II) before the outlet of the polymerization vessel (II). It is extracted by the polymerization liquid extraction pump installed in the column, heated to 230 ° C in a multi-tube heat exchanger, and flushed in a tank whose absolute pressure is reduced to 4 kPa to separate and remove the solvent and unreacted monomers. A polymer was produced. The other conditions were as shown in Table 1, where the copolymer was continuously produced for 5 days and sampled every other day for evaluation. The produced pellets of the copolymer and the gel in the three-stage plate were evaluated. No foreign matter such as a polymer or an opaque resin was found. Further, after the completion of production for 5 days, the polymerization vessel (I) 1 was opened and inspected without washing. No deposit such as resin was found on the line 8 or the like.

Comparative Example 1 A copolymer was continuously produced under the conditions shown in Table 1 in the same manner as in Example 1 and sampled every other day for evaluation. When 2 days passed from the start of production, An opaque resinous foreign material became to be seen in the pellets of the copolymer produced in 1., and a gel polymer also came to be seen in the three-stage plate. In addition, the indication value of the pressure gauge 24 does not match the indication value of the pressure gauge 25 when 3 days have passed since the start of manufacturing, and the indication value of the pressure gauge 24 changes even if the indication value of the pressure gauge 25 changes. I have stopped doing it. After the completion of the production for 5 days from the start of the production, when the polymerization vessel (I) 1 was opened and inspected without washing the can, the nozzle of the pressure gauge 24 was clogged with the resin. Further, resin deposits were found on the nozzle of the thermometer 23, the nozzle of the pressure gauge 25, the vapor line 8 and the like. Moreover, these plugged substances and deposits were not only ethylbenzene used as a solvent but also those produced normally. It was also insoluble in organic solvents such as N, N-dimethylformamide and acetone which easily dissolve the polymer.

Comparative Example 2 The liquid to be sprayed on the gas phase portion 16 of the polymerization can (I) 1 was only a part of the raw material, and the entire vapor condensate was joined to the feed liquid supply line. The other conditions were as shown in Table 1, and the copolymer was continuously produced in the same manner as in Example 1, and the samples were evaluated every other day. The pellets and the three-stage plate of the produced copolymer were evaluated. No foreign matter such as gel polymer or opaque resin was found inside. However, after the completion of the production for 5 days from the start of the production, when the polymerization vessel (I) 1 was opened and inspected without washing it, resin deposits on the nozzle of the thermometer 23, the nozzle of the pressure gauge 24, the vapor line 8 and the like. Moreover, these deposits are insoluble not only in ethylbenzene used as a solvent but also in an organic solvent such as N, N-dimethylformamide or acetone which easily dissolves a normally produced copolymer. there were.

[0050]

[Table 1]

[0051]

As is apparent from the above results, the continuous method for producing an aromatic vinyl-cyanide vinyl copolymer of the present invention simply involves cleaning the inner wall of the gas phase of a complete mixing tank type polymerization vessel. Not only to prevent the formation of polymer scales and polymer blocks, but also to prevent the polymerization of the condensate condensed by the nozzles and pipes connected to the complete mixing tank type polymerizer, which lowers the heat transfer capacity and reduces the High productivity is maintained while maintaining high productivity without causing problems such as a decrease in effective area and increase in pressure loss due to it, blockage, and deterioration of product appearance and mechanical properties due to gel polymer inclusion in the product. This is a method that enables stable production for a certain period and is extremely beneficial.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an example of a polymerization vessel (I) in the method for producing a copolymer of the present invention.

[Explanation of symbols]

1: Polymerizer (I) 2: Supply liquid supply line 3: Spray 4: Steam condensate supply line 5: Flow meter 6: Control valve 7: Check valve 8: Vapor line 9: Condenser 10: Buffer tank 11: Steam condensate extraction pump 12: Level gauge 13: Control valve 14: Liquid thermometer 15: Liquid level 16: Gas phase section 17: Liquid phase part 18: Jacket division position 19: Gas phase jacket 20: Liquid phase jacket 21: Stirrer 22: Stirrer motor 23: Thermometer 24: Pressure gauge (nozzle size 15A) 25: Pressure gauge (nozzle size 50A) 26: Polymerization liquid extraction pump 27: Stop valve 28: Stop valve

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08F 212/10 C08F 2/00-2/60 C08F 220/44

Claims (5)

(57) [Claims] 1. A raw material mixed solution containing an aromatic vinyl-based monomer, a vinyl cyanide-based monomer, and another vinyl-based monomer copolymerizable with these is continuously co-polymerized in the presence of a solvent. In the method for producing a copolymer obtained by polymerizing, 50 to 80% by weight of an aromatic vinyl monomer, 50 to 20% by weight of a vinyl cyanide monomer, and other vinyl-based monomer copolymerizable therewith 100 parts by weight of monomer mixture liquid of 0 to 30% by weight, 10 to 50 parts by weight of solvent, and 0 polymerization initiator
-1 part by weight and 0 to 1 part by weight of a molecular weight regulator, a complete mixing tank type polymerization device (I) equipped with a condenser for condensing vapor in the gas phase part or a polymerization device (I) and a polymerization connected thereto. The polymerization temperature of the polymerization vessel (I) is set to 120 to 170 by continuously supplying it to a polymerization apparatus in which at least one vessel (II) is combined.
C., and the temperature and supply amount of the vapor condensate refluxed from the condenser of the polymerizer (I) are adjusted so that the total concentration of the condensate components having a boiling point of 120 ° C. or less at atmospheric pressure is 65% by weight or more. A continuous process for producing the copolymer, which is prepared and sprayed on the gas phase of the polymerization vessel (I). 2. In the polymerizer (I), the temperature of the outer portion of the wall of the polymerizer which is in contact with the gas phase portion is lower than the temperature of the gas phase portion and is 0.
The temperature is adjusted to ~ 120 ° C.
A method for continuously producing the copolymer described. 3. In the polymerization vessel (I), a feed liquid having a polymerization conversion rate of less than 30% by weight at its inlet is copolymerized at a polymerization conversion rate of more than 30% by weight / hr, and the polymerization vessel (I) ), The polymerization conversion rate at the outlet is 50 to 9
The continuous production method of the copolymer according to claim 1 or 2, wherein the content is 0% by weight. 4. The copolymer according to claim 1, wherein the aromatic vinyl monomer is styrene and the vinyl cyanide monomer is acrylonitrile. Continuous manufacturing method. 5. The vapor condensate condensed by a condenser connected to the polymerizer (I) is returned to the polymerizer (I) via a buffer tank, according to any one of claims 1 to 4. A method for continuously producing the copolymer described.