KR102571367B1 - Method for preparing acrylonitrile based polymer - Google Patents

Abstract

The present invention is a method for producing a continuous acrylonitrile-based copolymer comprising a reaction system including two or more types of reactors, wherein a raw material mixture containing acrylonitrile-based monomers is prepared in the presence of a polymerization initiator in a continuous stirring reactor. A first polymerization step of primary polymerization; And a second polymerization step of transferring the primary polymerized raw material mixture to a static mixer and performing secondary polymerization in the static mixer, wherein the primary polymerized raw material mixture has a viscosity of 40,000 cP to 70,000 cP at 45 ° C. A method for producing an acrylonitrile-based copolymer is provided.

Description

Manufacturing method of acrylonitrile-based copolymer {METHOD FOR PREPARING ACRYLONITRILE BASED POLYMER}

The present invention relates to a method for producing an acrylonitrile-based copolymer used in the production of carbon fibers, and relates to a method for producing a continuous acrylonitrile-based copolymer including a reaction system including two or more reactors.

Carbon fiber is a fibrous carbon material composed of 90% by weight or more of carbon elements with respect to the total weight, and is a fiber type made from polyacrylonitrile (PAN), petroleum-based or coal-based hydrocarbon residues such as pitch or rayon. It means a fiber obtained by thermally decomposing the precursor of .

Carbon fiber is a material that has the structural and structural characteristics of carbon, which is a component, and has a fiber form. , biocompatibility, flexibility, etc., and depending on the activation conditions, very good adsorption properties can be imparted.

Meanwhile, acrylonitrile-based polymers are widely used as raw materials for carbon fiber precursors. A solution polymerization method is mainly used as a method for producing acrylonitrile-based polymers. In the solution polymerization method, a mixture of an acrylonitrile-based monomer, a polymerization initiator, and a reaction solvent can be used as a spinning solution, and the process is simplified without going through the step of dissolving the acrylonitrile-based polymer in a spinning solvent to make a spinning solution. It has the advantage of being economical.

On the other hand, in order to improve the productivity of PAN-based carbon fibers, efforts are being made to improve efficiency in all processes such as spinning, stabilization, or carbonization of carbon fiber precursors. However, when the PAN-based carbon fiber precursor is spun, there is a limit of the draft ratio according to the characteristics of the PAN-based polymer solution and the draw ratio according to the solidification structure. As a result, when the spinning speed is increased to improve productivity, the elongation of the PAN-based carbon fiber is lowered, and when the spinning speed is lowered, productivity is lowered, so it is difficult to achieve both productivity improvement and product performance improvement.

In order to solve this problem, Patent Document 1 includes a small amount of ultra-high molecular weight components in the PAN-based polymer solution, even if it is spun at a high spinning draft rate, it is possible to obtain a precursor fiber of good quality without fiber damage, mass production of carbon fibers There is an advantage that this becomes possible, and a batch-type solution polymerization method is proposed as this method.

Specifically, the polymerization of the ultra-high molecular weight component and the polymerization of the normal molecular weight component are carried out in the same reaction solution by introducing a reagent such as a polymerization initiator in two separate steps. Through this, a PAN-based polymer solution having excellent stringiness can be easily obtained. It is suggested that there is

However, in order to obtain a predetermined polymerization rate of the ultra-high molecular weight component, strict control of the timing of reagent input is required, and in the case of repeated polymerization in the same reactor, the remaining reagent affects the polymerization specification and also has a high viscosity, so that the gel in the reactor Since a large amount of production occurs, separate measures such as frequent washing of the reactor are required, and the uniformity of physical properties of the PAN-based polymer produced in a batch method is greatly reduced, resulting in quality deviation.

On the other hand, in the case of Patent Document 2, a method for producing an acrylonitrile-styrene copolymer by repeating the continuous process twice or more is proposed. In the case of a solution having a high conversion rate and a high viscosity, such as a PAN-based polymer solution, Since the volume of the reactor for performing the cooling process is relatively large, the economics of the manufacturing process is reduced, and a large amount of gel is generated in the reactor due to low agitation and heat removal performance.

Therefore, simultaneous achievement of quality improvement and productivity improvement is still a situation in which improvement is required.

JP 2008-248219 A KR 1999-0001928 A

The present invention has been made to solve the above problems, and applies a continuous production method including a reaction system including two or more reactors, but can greatly improve the conversion rate while suppressing the degradation of physical properties, thereby increasing productivity. It is intended to provide a method for producing a greatly increased acrylonitrile-based copolymer.

According to one embodiment of the present invention in order to solve the above problems, a method for producing a continuous acrylonitrile-based copolymer comprising a reaction system including two or more reactors, in the presence of a polymerization initiator in a continuous stirring reactor A first polymerization step of primary polymerization of a raw material mixture containing acrylonitrile-based monomers; And a second polymerization step of transferring the primary polymerized raw material mixture to a static mixer and performing secondary polymerization in the static mixer, wherein the primary polymerized raw material mixture has a viscosity of 40,000 cP to 70,000 cP at 45 ° C. A method for producing an acrylonitrile-based copolymer is provided.

According to the manufacturing method of the acrylonitrile-based copolymer of the present invention, productivity can be maximized because the degradation of physical properties of the polymer can be suppressed and the conversion rate can be greatly improved through multi-stage polymerization using two reactors. And it is possible to provide an acrylonitrile-based copolymer having uniformly excellent physical properties.

1 is a schematic process diagram for a manufacturing process of an acrylonitrile-based copolymer according to the present invention.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention.

Terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that there is.

A method for producing an acrylonitrile-based copolymer according to an embodiment of the present invention is a method for producing a continuous acrylonitrile-based copolymer comprising a reaction system including two or more reactors, wherein a polymerization initiator is used in a continuous stirred reactor. A first polymerization step of primary polymerization of a raw material mixture containing an acrylonitrile-based monomer in the presence of; and a second polymerization step of transferring the primary polymerized raw material mixture to a static mixer for secondary polymerization in the static mixer, wherein the primary polymerized raw material mixture has a viscosity of 40,000 cP to 70,000 cP at 45°C. to be

According to the production method of the present invention, an acrylonitrile-based copolymer having uniform physical properties can be obtained, the reaction time can be shortened, and the conversion rate can be improved compared to the case of using only the batch polymerization method or the continuous polymerization method. It is possible to prevent the deterioration of physical properties due to the suppression of gel formation, which is a by-product, so that productivity can be greatly improved.

Conventionally, in order to polymerize PAN for carbon fiber, a batch polymerization process or a continuous agitation polymerization process has been performed alone. However, the batch polymerization process has a disadvantage in that the polymerization reaction rate is fast, but the uniformity of physical properties is lowered when a gaseous reactant is present. There is a disadvantage that the reaction rate is slow compared to the process, and if any method undergoes the polymerization process alone, there is a problem that the uniformity of physical properties and productivity of the manufacturing process are lowered.

Therefore, in the case of the present invention, the polymerization step of the raw material mixture containing the acrylonitrile-based monomers for preparing the acrylonitrile-based copolymer was subjected to different polymerization reactions using two or more reactors. Method for producing an acrylonitrile-based copolymer with a fast polymerization reaction rate and finally improved uniformity in physical properties in consideration of the viscosity and conversion rate during the polymerization of the raw material mixture when the polymerization reaction is performed using two or more reactors as in the present invention can provide.

More specifically, in a section where the polymerization conversion rate is relatively low and the viscosity is low, the uniformity of the polymerization reaction can be improved by using a continuous stirring reactor.

On the other hand, in a section where the polymerization conversion rate is relatively high and the viscosity is high, a static mixer, which is a reactor used when there is no gaseous reactant, can be used. When the polymerization reaction is performed using a static mixer, since the heat transfer area per unit volume inside the reactor is larger than that of a continuous stirred reactor, the heat removal issue can be alleviated, and the reaction rate is also faster than that of a continuous stirred reactor. Productivity of the manufacturing process can be improved.

Hereinafter, the manufacturing method according to the present invention will be described for each step.

<First Polymerization Step>

First, the first polymerization step is a step of performing primary polymerization of a raw material mixture including acrylonitrile-based monomers in the presence of a polymerization initiator in a continuous stirring reactor.

The first polymerization step is a step in which the raw material mixture including the acrylonitrile-based monomer initially starts polymerization in the presence of a polymerization initiator,

The viscosity of the primary polymerized raw material mixture may be 40,000 cP to 70,000 cP at 45°C, preferably 45,000 cP to 65,000 cP at 45°C, and more preferably 50,000 cP to 60,000 cP at 45°C.

In the case of the first polymerization step, it is a polymerization process performed in a continuous stirring reactor. When the viscosity of the primary polymerized raw material mixture is within the above range, the polymerization conversion rate or molecular weight distribution of the final polymer is excellent, and the continuous stirring reactor Formation of by-products (gels) due to deterioration in agitation and heat removal performance can be prevented.

As the continuous stirring reactor, it is preferable to use a continuous stirring reactor equipped with an agitator and a jacket so that heat removal performance can be relatively excellent.

The raw material mixture includes an acrylonitrile-based monomer.

For example, the acrylonitrile-based monomer may be at least one selected from the group consisting of acrylonitrile and methacrylonitrile, of which acrylonitrile may be preferred.

In addition, the raw material mixture may further include an organic solvent, and for example, the organic solvent may be at least one selected from the group consisting of dimethyl sulfoxide, dimethylformamide, and dimethylacetamide, among which dimethyl sulfoxide Sides may be preferred.

The raw material mixture includes 200 parts by weight to 500 parts by weight, preferably 240 parts by weight to 400 parts by weight, and more preferably 260 parts by weight to 320 parts by weight, based on 100 parts by weight of the acrylonitrile monomer. can do. When the organic solvent is included within the above range, the polymerization conversion rate and weight average molecular weight of the raw material mixture may be increased by optimally adjusting the viscosity of the raw material mixture.

Meanwhile, the raw material mixture may further include an additional monomer as a comonomer in addition to the acrylonitrile-based monomer. The comonomer may be, for example, at least one selected from the group consisting of carboxylic acid monomers and (meth)acrylate monomers.

The carboxylic acid-based monomer may be at least one selected from the group consisting of acrylic acid, methacrylic acid, ethacrylic acid, itaconic acid, crotonic acid, citraconic acid, maleic acid, and mesaconic acid, among which itaconic acid is preferred. The (meth)acrylate-based monomer may be at least one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, methyl methacrylate, ethyl methacrylate and propyl methacrylate, among which Methyl acrylate is preferred.

The comonomer may be included in an amount of 1 to 10 parts by weight, preferably 1 to 7 parts by weight, and more preferably 1 to 4 parts by weight, based on 100 parts by weight of the acrylonitrile-based monomer. If the above-described range is satisfied, not only can it play a role of lowering the starting temperature of the oxidation stabilization reaction in the manufacturing process of acrylonitrile-based fibers, but also it can impart appropriate stretchability to acrylonitrile-based fibers.

The polymerization reaction may be performed in the presence of a polymerization initiator, and the polymerization initiator is for initiating a polymerization reaction between acrylonitrile-based monomers or comonomers that may be added in addition to the raw material mixture.

For example, as a polymerization initiator, azobisisobutyronitrile, 2,2'-azobis (4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis (2,4-dimethyl valeronitrile), dimethyl 2,2'-azobis (2-methylpropionate), 1,1'-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis [N-( 2-propenyl)-2-methyl propionamide, [(cyano-1-methyl ethyl)azo]formamide, 2 2'-azobis(N-butyl-2-methyl propionamide), 2,2'- Azobis (N-cyclohexyl-2-methyl propionamide) and the like may be used, and among these, azobisisobutyronitrile is particularly preferred.

The polymerization initiator may be added in an amount of 0.2 parts by weight to 2.0 parts by weight, preferably 0.3 parts by weight to 1.0 parts by weight, and more preferably 0.4 parts by weight to 0.8 parts by weight, based on 100 parts by weight of the acrylonitrile-based monomer. When the polymerization initiator satisfies the aforementioned range, the final polymerization conversion rate of the obtained polymer may be improved.

<Second Polymerization Step>

Next, the second polymerization step is a step of transferring the primary polymerized raw material mixture to a static mixer and performing secondary polymerization in the static mixer.

In the first polymerization step, a continuous stirring reactor is used, whereas in the second polymerization step, a static mixer is used to perform secondary polymerization.

As mentioned above, when the polymerization reaction is performed only through the continuous stirring reaction, the polymerization reaction rate is slower than in the case of using a static mixer, and when the viscosity of the raw material mixture increases as the polymerization reaction proceeds, stirring And the heat removal performance is reduced, and by-products (gels) may be generated in the reactor. On the other hand, when the polymerization reaction is performed only through a static mixer, a decrease in physical properties may occur due to a temperature gradient in the front part of the reactor.

Therefore, according to one embodiment of the present invention, when the viscosity range that varies as the polymerization reaction proceeds is divided, and the viscosity and polymerization conversion rate are higher than a certain level as the raw material mixture is polymerized in the first polymerization step, it is transferred to a static mixer. After that, the second polymerization step was performed.

At this time, the viscosity of the first polymerized raw material mixture may be 40,000 cP to 70,000 cP at 45°C, preferably 45,000 cP to 65,000 cP at 45°C, and more preferably 50,000 cP to 60,000 cP at 45°C. .

In addition, the point at which the primary polymerized raw material mixture is transferred to the static mixer is when the polymerization conversion rate of the primary polymerized raw material mixture is 60% to 80%, preferably 70% to 80%, more preferably 70% to 80%. % to 75%.

If the primary polymerization of the raw material mixture is transferred when the polymerization conversion rate is less than the above range, the yield of the final product, acrylonitrile-based copolymer, is too low and the polymerization reaction must be additionally performed, resulting in a decrease in productivity. can As the second polymerization reaction is carried out for a longer time, there is also a concern that the physical properties of the copolymer may deteriorate.

On the other hand, when the polymerization conversion rate of the primary polymerized raw material mixture is transferred when the polymerization conversion rate exceeds the above range, as the viscosity of the raw material mixture increases in the continuous stirring reactor, the stirring and heat removal performance deteriorates, resulting in gel, which is a by-product in the reactor. There is a problem in that reactor contamination may become serious due to the formation of reactor volume, and the volume of the reactor must be increased to increase the reaction volume of the continuous stirred reactor. Therefore, in order to solve the above problems, it is preferable that the point at which the primary polymerized raw material mixture is transferred to the static mixer should be when the polymerization conversion rate of the primary polymerized raw material mixture is within the above range.

On the other hand, in the second polymerization step, a polymerization initiator is added secondarily. At this time, the polymerization initiator that is secondarily added may be the same as the above-mentioned polymerization initiator.

The additional polymerization initiator may be added in a mixed state with an organic solvent, and at this time, the organic solvent described above is used in the same way.

At this time, the polymerization initiator additionally added in the second polymerization step is 0.2 to 2.0 parts by weight, preferably 0.3 to 1.0 parts by weight, more preferably 0.4 to 0.8 parts by weight, based on 100 parts by weight of the raw material mixture. It may be part by weight. When the above range is satisfied, solution polymerization can be easily performed without lowering the polymerization conversion rate of the obtained polymer.

In addition, in the second polymerization step, control of the polymerization reaction temperature may be necessary, depending on the case. For example, the reaction temperature of the second polymerization step may preferably be 60 ° C to 80 ° C, and when the above range is satisfied, the molecular weight distribution may be narrowed (can be reduced), and thus the physical properties are lowered. can be suppressed and the conversion rate can be increased.

After being transferred to the static mixer, the viscosity of the secondary polymerized raw material mixture is 30,000 cP to 60,000 cP at 45°C, preferably 35,000 cP to 55,000 cP at 45°C, more preferably 40,000 cP to 50,000 cP at 45°C. can be

At this time, the polymerization conversion rate of the secondary polymerized raw material mixture may be 90% or more, preferably 90% to 95%, more preferably 90% to 93%.

When the secondary polymerized raw material mixture satisfies the above viscosity range and polymerization conversion rate range, it can be used as a spinning solution for preparing acrylonitrile-based fibers without additional treatment such as mixing a spinning solvent or the like. Even when the secondary polymerized raw material mixture is directly used as a spinning solution, deterioration in stretchability of manufactured fibers can be prevented without causing defects in the process such as clogging of the spinning outlet.

Meanwhile, the molecular weight distribution of the secondary polymerized raw material mixture according to Equation 1 below may be 2.0 Mw/Mn to 4.0 Mw/Mn, preferably 2.4 Mw/Mn to 3.0 Mw/Mn.

[Equation 1]

Molecular weight distribution = weight average molecular weight (Mw) / number average molecular weight (Mn)

When the secondary polymerized raw material mixture has a molecular weight distribution within the above range, there is an advantage in that the conversion rate is excellent and the decrease in molecular weight distribution value is suppressed, thereby suppressing the resulting decrease in physical properties.

Example

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

Example 1

A reaction solution was prepared by uniformly dissolving 100 parts by weight of a monomer mixture in which acrylonitrile and itaconic acid were mixed in a molar ratio of 99.47:0.53 in 279.0 parts by weight of dimethyl sulfoxide and 0.6 parts by weight of azobisisobutyronitrile as a radical polymerization initiator. .

The reaction solution was put into the raw material mixture tank 1 equipped with an agitator, and nitrogen was purged to remove dissolved oxygen.

Thereafter, the reaction solution was introduced into a continuous stirred reactor (CSTR) (3) purged with nitrogen in advance at a predetermined flow rate using the raw material mixture transfer pump (2), and the temperature of the reaction solution in the reactor was maintained at 68 ° C.

Thereafter, after 10 hours have elapsed since the introduction of the reaction solution into the continuous stirring reactor (CSTR), the reaction solution was taken out from the bottom of the reactor using a pump, and then the first polymer transport pump 4 was used to transfer the static reaction solution. added to the mixer.

At the same time, a radical polymerization initiator solution (including 0.6 parts by weight of azobisisobutyronitrile relative to 100 parts by weight of the radical polymerization initiator solution) corresponding to 20 parts by weight of the reaction solution flow rate 100 parts by weight of the polymerization initiator solution tank (5) From there, the polymerization initiator solution was introduced into the static mixer 7 through the transfer pump 6. At this time, the temperature of the reaction solution in the static mixer 7 was maintained at 75° C., and the reaction solution was added until the residence time in the static mixer 7 reached 3 hours.

Thereafter, when the temperature, flow rate, load of the agitator, pressure of the static mixer 7, etc. in the static mixer 7 become constant, it is determined that a steady state has been reached, and then the acrylonitrile-based copolymer at the rear of the static mixer 7 A solution was obtained.

The polymerization conversion rate in the continuous stirred reactor (CSTR) (3) was 75.1%, and the viscosity at 45°C was 55,700cp, and the conversion rate of the acrylonitrile-based copolymer obtained at the rear end of the static mixer (7) was 91.9%, 45°C The viscosity was 37,100 cp. The process at this time is also shown in FIG.

Example 2

An acrylonitrile-based copolymer was prepared in the same manner as in Example 1, except that the polymerization conversion rate in the continuous stirred reactor (CSTR) (3) was adjusted to 72.3% and the viscosity was adjusted to 51,500 cP at 45 ° C. .

Example 3

Except that the temperature in the static mixer 7 was adjusted to 80° C. so that the polymerization conversion rate in the static mixer 7 was 93.2% and the viscosity was 45,700 cP at 45° C., the acrylic was prepared in the same manner as in Example 1. A nitrile-based copolymer was prepared.

Example 4

Except that the temperature in the static mixer 7 was adjusted to 85° C. so that the polymerization conversion rate in the static mixer 7 was 94% and the viscosity was 42,300 cP at 45° C., the acrylic was prepared in the same manner as in Example 1. A nitrile-based copolymer was prepared.

[Comparative example]

Comparative Example 1

A reaction solution was prepared by uniformly dissolving 100 parts by weight of a monomer mixture in which acrylonitrile and itaconic acid were mixed in a molar ratio of 99.47:0.53 in 279.0 parts by weight of dimethyl sulfoxide and 0.6 parts by weight of azobisisobutyronitrile as a radical polymerization initiator. .

The reaction solution was put into a raw material mixing container equipped with an agitator, and nitrogen was purged to remove dissolved oxygen.

Thereafter, the reaction solution was introduced into a first continuous stirred reactor (CSTR) purged with nitrogen in advance at a predetermined flow rate using a pump, and the temperature of the reactants in the reactor was maintained at 68°C.

Then, after 10 hours have elapsed since the introduction of the reaction solution into the first continuous stirred reactor (CSTR), the reaction solution was taken out from the bottom of the reactor using a pump, and then transferred to the second continuous stirred reactor (CSTR). was put into.

At the same time, a polymerization initiator solution corresponding to 20 parts by weight based on 100 parts by weight of the reaction solution in the second continuous stirred reactor (CSTR) (0.8 parts by weight of azobisisobutyronitrile relative to 100 parts by weight of the polymerization initiator solution) was added to a static mixer using a pump. At this time, the temperature of the reaction solution in the second continuous stirring reactor (CSTR) was maintained at 75° C., and the reaction solution was allowed to stay for 3 hours.

The finally obtained acrylonitrile-based copolymer had a polymerization conversion rate of 86.0% and a viscosity of 30,500cp at 45°C.

Comparative Example 2

An acrylonitrile-based copolymer was prepared in the same manner as in Comparative Example 1, except that the residence time after being introduced into the second continuous stirring reactor (CSTR) was 4.5 hours.

Comparative Example 3

An acrylonitrile-based copolymer was prepared in the same manner as in Comparative Example 1, except that the retention time after being introduced into the second continuous stirring reactor (CSTR) was 7.5 hours.

Comparative Example 4

The polymerization conversion rate in the continuous stirred reactor (CSTR) was adjusted to 71.8%, the viscosity was adjusted to 57,910 cP at 45 ° C, and the acrylonitrile-based air was the same as in Example 1 except that a static mixer was not used. A composite was prepared.

Experimental Example 1

The polymerization conversion rate and molecular weight distribution (PDI: Mw/Mn) of the acrylonitrile-based copolymers prepared in Examples and Comparative Examples were measured and listed in Table 1 below.

1) Polymerization conversion rate

0.5 g of the obtained polymer solution was precipitated in water, washed with warm water, and dried under reduced pressure at 120°C for 2 hours. The weight of the dried resin was measured to measure the solid content, and the polymerization conversion rate was measured by the following formula.

Polymerization conversion rate (%): (Measured solid content)/ (Solid content per 0.5 g of reaction solution calculated as the ratio of solid content and solvent introduced into the reactor) Х100

2) molecular weight distribution (PDI)

The weight average molecular weight (Mw) and number average molecular weight (Mn) of 1 g of the obtained polymer solution were measured using GPC (Gel Permeation Chromatography) under the following conditions, and the molecular weight distribution was calculated.

Column: PLmixed B Х 2, solvent: DMF/0.05 M LiBr (0.45㎛ Filtered), flow rate: 1.0 ml/min, sample concentration: 4.0 mg/ml, injection amount: 100 μl, column temperature: 65, detector: Waters RI Detector , Standard: PMMA)

CSTR stay time Static Mixer Residence Time polymerization conversion rate
(%) Molecular Weight (Mw) molecular weight distribution
(Mw/Mn) Example 1 10 3 91.9 303,000 2.76 Example 2 9 3 91.5 299,000 2.81 Example 3 10 3 93.2 305,000 3.19 Example 4 10 3 94.0 295,000 3.42 Comparative Example 1 10 3 86.0 313,000 3.14 Comparative Example 2 10 4.5 86.9 260,000 3.01 Comparative Example 3 10 7.5 88.1 280,000 3.20 Comparative Example 4 9 3 71.8 375,000 2.00

Referring to Table 1, it can be confirmed that the polymerization conversion rate of the acrylonitrile-based copolymer prepared according to the examples is improved.

1. Raw material mixture tank
2. Raw material mixture transfer pump
3. Continuous Stirred Reactor (CSTR)
4. First polymer transfer pump
5. Polymerization initiator solution tank
6. Polymerization initiator solution transfer pump
7. Static Mixer

Claims (7)

A method for producing a continuous acrylonitrile-based copolymer comprising a reaction system including two or more types of reactors,
A first polymerization step of performing primary polymerization of a raw material mixture including an acrylonitrile-based monomer in the presence of a polymerization initiator in a continuous stirring reactor; and
A second polymerization step of transferring the primary polymerized raw material mixture to a static mixer and performing secondary polymerization in the static mixer;
The viscosity of the primary polymerized raw material mixture is 40,000 cP to 70,000 cP at 45 ° C,
The method for producing an acrylonitrile-based copolymer, wherein the primary polymerized raw material mixture is transferred to the static mixer when the polymerization conversion rate of the primary polymerized raw material mixture is 60% to 80%.
According to claim 1,
The viscosity of the secondary polymerized raw material mixture is a method for producing an acrylonitrile-based copolymer of 30,000 cP to 60,000 cP at 45 ° C.
delete According to claim 1,
The method of producing an acrylonitrile-based copolymer, wherein the primary polymerized raw material mixture is transferred to the static mixer when the polymerization conversion rate of the primary polymerized raw material mixture is 70% to 80%.
According to claim 1,
Method for producing an acrylonitrile-based copolymer, wherein the polymerization conversion rate of the secondary polymerized raw material mixture is 90% or more.
According to claim 1,
Method for producing an acrylonitrile-based copolymer having a molecular weight distribution of 2.0 Mw/Mn to 4.0 Mw/Mn according to Equation 1 below of the secondary polymerized raw material mixture:
[Equation 1]
Molecular weight distribution = weight average molecular weight (Mw) / number average molecular weight (Mn)
According to claim 6,
The weight average molecular weight of the secondary polymerized raw material mixture is a method for producing an acrylonitrile-based copolymer of 295,000 Mw to 305,000 Mw.