WO2003012399A1

WO2003012399A1 - Method for determining polymerization conversion, method and apparatus for producing polymer and polymerization reactor

Info

Publication number: WO2003012399A1
Application number: PCT/JP2002/007721
Authority: WO
Inventors: Minoru Matsuura
Original assignee: Zeon Corporation
Priority date: 2001-07-31
Filing date: 2002-07-30
Publication date: 2003-02-13
Also published as: JPWO2003012399A1

Abstract

A method for determining a polymerization conversion which comprises measuring a density of a polymerization reaction mixture by mans of a vibrating densimeter, and calculating the value of polymerization conversion of the polymerization reaction mixture from the resultant value of density. The method, which determines a polymerization conversion by using a density of a polymerization reaction mixture measured by a vibrating densimeter, allows the determination of a polymerization conversion with simple and easy operations, with high accuracy of measurement, and in a short time, and further, allows the determination of a conversion to be carried out through the measurement by a densimeter attached to the inside of a polymerization reactor, without taking a polymerization mixture out of the reactor.

Description

Akira Itoda method for measuring polymerization conversion, method and apparatus for producing polymer, and polymerization reactor

The present invention relates to a method for measuring a polymerization conversion rate of a polymerization reaction solution, a method and an apparatus for producing a polymer using the method, and a polymerization reaction tank used for these. Background art

The polymerization conversion is widely used as one of the indicators of the progress of polymerization. However, in order to directly measure the polymerization conversion, a polymerization reaction solution is sampled and the amount of unreacted monomer contained therein is measured or the amount of polymer is measured. I have to call. It takes a long time to directly measure the polymerization conversion rate using either method, and if it is intended to determine the end time of polymerization based on the polymerization conversion rate obtained by such a method, the measurement results When this is obtained, a situation may occur in which the polymerization conversion rate has already exceeded the target. If the termination time is determined based on the polymerization conversion at an early stage to avoid this problem, there is a problem because the difference from the target polymerization conversion becomes large. For this reason, a method for obtaining the polymerization conversion rate from properties that are considered to be correlated with the polymerization conversion rate is being studied.

In emulsion polymerization, attention has been paid to the difference in density between the monomer and the polymer, and a method for calculating the polymerization conversion rate from the change in the density of the polymerization reaction solution has been proposed (S. PONNUSW AMY et al., “ON- LI NE MON I TOR I NG OF P OLYMER IZ AT I ON REACTOR ", Journalof Applied P o 1 ymer Science, vol. 3 2, 3 23 9—3 253 (1 986), S. CANEGALLO et al. , "Densi me tryfor On—Line C onversion Monitoringin Emu 1sion Homo—ad Cop ol y mer rization", Journa 1 of Applied P ol ymer S cience, vol. 47, 9 6 1-9 7 9 (1 9 9 3)). In these methods, as a method of measuring the density The methods used are (1) a method of measuring from the magnitude of the reverberation to the applied vibration,

(2) A method of analyzing and measuring data from a mass flow meter, and (3) A method of measuring from the results of concentration measurement using a color difference meter.

However, when using the magnitude of the reverberation in (1), it is necessary that the measurement target be in a pipe with a fixed inner diameter, and in the method using a mass flow meter in (2), a certain flow in the pipe is required. It is. In the method of measuring density using a color difference meter in (3), the polymerization reaction solution is placed in a transparent measurement cell, and the sample is irradiated with light to measure the absorbance. For this reason, in any of the methods (1) to (3), measurement inside the polymerization reaction tank is difficult. Therefore, in these methods, it is necessary to take out the polymerization reaction liquid from inside the polymerization reaction tank to the outside of the polymerization reaction tank, measure the density, return the polymerization reaction liquid to the polymerization reaction liquid, and install a circulation pipeline. There is.

However, when a circulation pipeline was installed, the inside of the pipe was easily clogged, and the inside of the pipe was required to be cleaned even when the polymerization reactor did not need to be cleaned. Cleaning the inside of a pipe is very complicated, and it takes time, especially when removing and cleaning the pipe, and frequent removal is not preferable from the viewpoint of the safety of the equipment. Disclosure of the invention

An object of the present invention is to provide a method for measuring the polymerization conversion rate which can accurately and quickly measure the polymerization conversion rate of a polymerization reaction liquid without taking the polymerization reaction liquid out of the polymerization reaction tank. To provide. Further, the present invention provides a method and an apparatus for producing a polymer capable of industrially producing a polymer having a desired quality without delaying the completion of the reaction, and a polymerization reaction used in these. The purpose is to provide a tank.

The present inventors do not directly measure the polymerization conversion rate of the polymerization reaction solution during and after the polymerization or after the completion of the polymerization, but can perform the measurement in a relatively short time, and have a correlation with the polymerization conversion rate. We explored physical properties that could be used instead. As a result, it was found that there was a predetermined correlation between the density of the polymerization reaction solution and the polymerization conversion rate of the polymerization reaction solution. We also found that the use of a vibratory densitometer enables the density of a polymerization reaction solution to be measured in a short time with high measurement accuracy. Furthermore, this vibratory density meter is superposed It was also learned that the density of the polymerization reaction solution can be measured without taking the polymerization reaction solution out of the polymerization reaction tank by installing it inside the reaction tank. Based on these findings, the present invention has been completed.

That is, according to the present invention,

Measuring the density of the polymerization reaction solution using a vibration type densitometer attached inside the polymerization reaction tank;

Calculating the value of the polymerization conversion rate of the polymerization reaction solution from the measured value of the density.

According to the present invention, the polymerization conversion rate of the polymerization reaction solution is not directly measured, and the density of the polymerization reaction solution, which is a substitute property thereof, is measured using a vibrating densitometer, and the density is measured. The value of the polymerization conversion rate of the polymerization reaction solution is calculated. Since the density of the polymerization reaction solution is measured using a vibrating densitometer, the density of the polymerization reaction solution can be obtained with a simple operation with high measurement accuracy and in a short time. In addition, since the vibrating densitometer is installed inside the polymerization reaction tank, the density can be measured inside the polymerization reaction tank without taking out the polymerization reaction solution outside the polymerization reaction tank.

According to the present invention,

A step of obtaining a polymerization reaction solution by a polymerization reaction,

Measuring the density of the polymerization reaction solution using a vibration type densitometer attached inside the polymerization reaction tank,

Calculating a value of a polymerization conversion rate of the polymerization reaction solution from the value of the measured density;

Changing the polymerization reaction factor in accordance with the calculated value of the polymerization conversion rate of the polymer reaction solution.

According to the present invention,

A raw material supply step of supplying a raw material comprising a monomer, a polymerization initiator and other polymerization auxiliary materials to a polymerization reaction tank;

A method for producing a polymer, comprising: a polymerization step of polymerizing a monomer in the polymerization reaction tank to obtain a polymerization reaction solution; and a polymerization termination step of terminating polymerization at a predetermined polymerization conversion rate. Measuring the density of the polymerization reaction solution in the polymerization reaction tank using a vibration type densitometer attached inside the polymerization reaction tank;

The calculated value of the polymerization conversion rate of the polymerization reaction liquid is transmitted to at least one step selected from the raw material supply step, the polymerization step, and the polymerization termination step, and the polymerization reaction factor in each step is changed. A method for producing a polymer having a factor changing step is provided.

The method for producing each polymer according to the present invention can be realized by, for example, the following apparatus.

The apparatus for producing a polymer according to the present invention includes:

A polymerization reaction tank for obtaining a polymerization reaction solution by a polymerization reaction,

A vibratory densitometer mounted inside the polymerization reaction tank and measuring the density of the polymerization reaction solution in the polymerization reaction tank;

A polymerization conversion rate calculating means for calculating a value of a polymerization conversion rate of the polymerization reaction solution from a value of the density measured by the densitometer;

A factor changing means for changing a polymerization reaction factor in accordance with the value of the polymerization conversion rate of the polymerization reaction solution calculated by the polymerization conversion rate calculating means.

According to these inventions, a polymer having a desired quality can be produced industrially advantageously without losing the end time of the reaction.

According to the present invention,

Changing the polymerization reaction factor in accordance with the measured value of the density.

According to the present invention,

A raw material supply step of supplying a raw material comprising a monomer, a polymerization initiator and other polymerization auxiliary materials to a polymerization reaction tank; A method for producing a polymer, comprising: a polymerization step of polymerizing a monomer in the polymerization reaction tank to obtain a polymerization reaction solution; and a polymerization termination step of terminating polymerization at a predetermined polymerization conversion rate. ,

Measuring the density of the polymerization reaction solution in the polymerization reaction tank using a vibration type densitometer attached inside the polymerization reaction tank;

Transmitting the value of the measured density to at least one step selected from the raw material supply step, the polymerization step and the polymerization stop step, and a factor changing step of changing a polymerization reaction factor in each step; A method for producing a polymer having the same is provided.

And a factor changing means for changing a polymerization reaction factor in accordance with the value of the density measured by the densitometer.

As described above, the present inventors have found that there is a predetermined correlation between the density of the polymerization reaction solution and the polymerization conversion rate of the polymerization reaction solution. Even if the polymerization conversion rate is not calculated from the density of the reaction solution, the same effect can be obtained by controlling the density of the polymerization reaction solution. That is, even with these methods, a polymer having the desired quality can be industrially advantageously produced without losing the end time of the reaction.

In the method and apparatus for producing each polymer according to the present invention, for example, the following polymerization reaction tank can be used.

The polymerization reaction tank according to the present invention has a vibration type densitometer installed so that the measurement terminal is immersed in the polymerization reaction solution to be obtained inside.

In the present invention, it is preferable to use a tuning fork type vibratory densitometer to measure the density of the polymerization reaction solution with higher measurement accuracy and in a shorter time.

In the present invention, it is preferable to use an emulsion polymerization reaction liquid as the polymerization reaction liquid. In the present invention, it is preferable to use an emulsion polymerization reaction solution of a copolymer composed of an unsaturated ether or aromatic vinyl and a conjugated diene.

In the present invention, the polymerization reaction factor is at least one selected from a raw material supply element, a polymerization element, and a polymerization termination element, and the raw material supply element is a monomer, a polymerization initiator, and other polymerization auxiliary materials. At least one selected from the presence or absence of additional charge, the timing of additional charge, and the amount of additional charge, wherein the polymerization element controls the flow rate of a cooling medium or a heat medium that controls the reaction temperature, the reaction pressure, the stirring speed of the polymerization reaction tank, and the like. It is at least one selected from a method of stirring the polymerization reaction tank, and the polymerization terminating element is at least one selected from charging of a polymerization terminator, cooling in the polymerization reaction tank, and depressurization in the polymerization reaction tank. It is preferred that

In the present invention, the calculated value of the polymerization conversion rate of the polymerization reaction solution is transmitted to the raw material supply step, and at least one selected from the presence or absence of additional input of each raw material, the timing of additional input, and the additional input amount. One can change. In the present invention, the measured density value is transmitted to the raw material supply step, and at least one selected from the presence / absence of additional input of each raw material, the time of additional input, and the additional input amount is changed. it can. In the present invention, the monomer and / or the polymerization initiator can be additionally charged into the polymerization reaction tank at least once between the start of the polymerization and the termination of the polymerization.

In the present invention, the calculated value of the polymerization conversion rate of the polymerization reaction solution is transmitted to the polymerization termination step, and the value is selected from the addition of a polymerization terminator, the cooling in the polymerization reaction vessel, and the reduced pressure in the polymerization reaction vessel. Preferably, the polymerization reaction is stopped by at least one of the methods described above. In the present invention, the value of the measured density is transmitted to the polymerization stopping step, and at least one selected from charging of a polymerization stopping agent, cooling in the polymerization reaction tank and depressurization in the polymerization reaction tank is selected. It is preferable to stop the polymerization reaction by a method.

In the present invention, it is preferable to use unsaturated nitrile or aromatic vinyl and a conjugated diene as monomers. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram showing an example of an apparatus for realizing a method for producing a polymer by patch-type emulsion polymerization according to an embodiment of the present invention. FIG. 2 is a diagram showing the relationship between the density of the polymerization reaction solution and the polymerization conversion rate of the polymerization reaction solution in Example 1 (however, the straight line in the diagram shows the relationship obtained by regression analysis). FIG. 3 is a cross-sectional view showing an example of a polymerization reaction tank used in the apparatus of FIG.

FIG. 4 is a conceptual diagram showing a vibratory densitometer attached to the polymerization reactor of FIG. BEST MODE FOR CARRYING OUT THE INVENTION

In the following description, a method for measuring the polymerization conversion rate according to the present invention, a method for producing a polymer using the method, a production apparatus as an example for realizing the production method, and a polymerization reaction tank used for the production apparatus , And will be described in this order.

The polymerization reaction liquid applicable to the present invention is not particularly limited as long as the density of the polymerization reaction liquid changes depending on the polymerization conversion rate and the change in density can be measured with a vibrating densitometer. It may be obtained by solution polymerization or may be obtained by other than solution polymerization. As an example of the latter, the method of the present invention can be applied to a polymerization reaction solution in which the polymer particles are an emulsion in which the polymer particles are uniformly dispersed in the emulsion.

Examples of the polymer emulsion applicable to the present invention include, but are not limited to, homopolymers or copolymers composed of only conjugated gens such as butadiene polymer, isoprene polymer, and butadiene-isoprene copolymer; acryloetrile-butadiene copolymer Unsaturated nitriles such as acrylonitrile-butadiene-isoprene copolymer, acrylonitrile-co-isoprene copolymer, acrylonitrile-styrene-butadiene copolymer, and acrylonitrile-styrene-styrene-isoprene copolymer Copolymers composed of styrene and conjugated diene; aromatic vinyls such as styrene-butadiene copolymer and styrene-isoprene copolymer other than copolymers composed of unsaturated nitrile and conjugated diene And conjugated gen; Ethyl acrylate polymer, Ethyl acryle Homo- or copolymers composed solely of acrylates such as toe η-butyl acrylate copolymer, ethynoleacrylate-monobutyl acrylate and 2-methoxyl acrylate copolymer; Examples of the polymerization reaction liquid are emulsions of various polymers. Among them, a copolymer composed of unsaturated nitrile and a conjugated diene, and a polymerization reaction solution of a homopolymer composed solely of acrylate or a copolymer are preferable. A polymerization reaction solution of a copolymer composed of an unsaturated-tolyl and a conjugated diene is more preferable, and a polymerization reaction solution of an atarilonitrile-butadiene copolymer is particularly preferable. Polymer emulsion, for example, emulsion polymerization, seeding? Although it can be obtained by Lich polymerization, fine suspension polymerization, or seeded fine suspension polymerization, in the present invention, it is preferable to use an emulsion polymerization reaction solution obtained by emulsion polymerization.

The emulsion polymerization reaction liquid often contains an emulsifier, an unreacted monomer, and a polymerization initiator or a residue of a polymerization initiator, in addition to the above polymer and water. In addition, it may contain a molecular weight regulator, a cocatalyst, a pH regulator, and the like. Further, the emulsion polymerization reaction liquid may be in the course of polymerization or after the polymerization.

The content of each component of the polymerization reaction solution is not particularly limited as long as the density can be made uniform by stirring.

In the present invention, a vibration type densitometer is used for measuring the density of the polymerization reaction solution. The vibratory densitometer vibrates a vibrator (also called a sensitive plate) at a constant frequency and amplitude in a reaction solution sample, and determines the driving force or vibration attenuation required to drive the vibrator, and the density of the reaction solution sample. This is a device that measures the density of the reaction solution sample by the correlation between By using this vibratory densitometer, measurement accuracy can be improved.

There are various types of vibratory densitometers. For example, it is one of the “single vibration type” that vibrates one vibrator like a pendulum, and the “ultrasonic vibration type” that vibrates one vibrator like a pendulum by ultrasonic waves. There are “torsional vibration type”, in which one vibrator is torsionally vibrated, and “tuning fork vibration type”, in which two vibrators resonate.

There are two types of simple vibration type: one to measure the attenuation of the amplitude due to the density, and the other to measure the current value required for maintaining a constant amplitude. There is a disadvantage that since it is a simple vibration, external influences such as reflected vibration from the container are relatively large. In the torsional vibration method, the detection terminal vibrates in the rotational direction so as to resonate at a certain frequency, the tip (detection end) of the detection terminal is immersed in a liquid, and the amplitude of the vibration changes depending on the density of the liquid. This is interpreted as a change in angular acceleration and converted to an electronic signal for measurement. The tuning fork type vibrator is based on the fact that the amount of current required to maintain the vibrator at a constant frequency and a constant amplitude increases and decreases with the density of the sample. It measures the amount of current and converts it to a density value.

In the present invention, each of the above types can be appropriately selected and used. However, if a higher measurement accuracy and a shorter measurement time are desired, it is preferable to use a tuning fork type vibratory density meter. The tuning fork type vibratory density meter vibrates in opposite directions when the two vibrators as the measurement terminals resonate, so that external effects such as reflected vibration from the container are more likely to be canceled out, and compared to other types. Measurement error is small and the response is excellent.

The mounting position of the tuning fork type vibratory density meter is not particularly limited as long as the two vibrators are mounted so as to be immersed in the polymerization reaction solution in the polymerization reaction tank. Since these two vibrators are projections on the inner surface of the polymerization reaction tank, the polymer easily adheres to them.However, compared with projections such as measurement terminals of a density meter installed in the circulation pipeline, the polymer is attached. It is difficult to attach and can be easily removed even if attached. Also, if the two vibrators are always vibrating during polymerization, the polymer will not easily adhere and accurate measurement will be difficult. Measurement range of the density of the vibration type density meter, in order to reduce the measurement error is preferably 6 0 0~ 1 2 0 0 kg / m 3, more preferably 7 0 0~: L l OO kg / m 3 , particularly preferably 8 0 0~ 1 0 5 0 kg / m 3.

In the present invention, the value of the polymerization conversion rate of the polymerization reaction solution is calculated from the measured value (measured value) of the density of the polymerization reaction solution based on a predetermined conversion formula. The value of the polymerization conversion may be calculated manually, but the calculation time can be easily reduced by using an information processing device such as a computer.

The method of calculating the value of the polymerization conversion rate from the measured value of the density of the polymerization reaction solution is as follows.The relationship between the density of the polymerization reaction solution and the polymerization conversion rate is obtained in advance in the form of a conversion formula under the same polymerization conditions. What is necessary is just to calculate and obtain based on the conversion formula.

The polymerization conversion rate used for obtaining the relational expression is determined by collecting the polymerization reaction solution, measuring the amount of unreacted monomer contained therein, and quenching by the polymerization reaction among the monomers subjected to polymerization. Determined as the ratio of the amount consumed, or based on the amount of polymer contained in the polymerization reaction liquid relative to the amount of monomer subjected to polymerization. The amount of unreacted monomer in the polymerization reaction solution can be determined by, for example, chromatographic analysis. Further, the amount of the polymer in the polymerization reaction solution may be determined by separating the polymer from the polymerization reaction solution, washing and drying. The conversion formula to the polymerization conversion value can usually be determined by regression analysis. Alternatively, an initial conversion formula may be obtained, and this may be optimized over time. The initial conversion formula f (1) (p) is obtained by, for example, preparing several types of polymerization reaction solutions having different polymerization conversion rates, measuring the density of each polymerization reaction solution, and obtaining the least squares method of the density and the polymerization conversion rate. be able to. Next, the density P ( ₂₎ of the polymerization reaction solution during or after polymerization is measured, and M _(1> ) is calculated using M ₍₁ ) = f (i) (p (2)). M ₍₂₎ is measured, and an optimized equation f ₍₂₎ (p) is obtained based on the new data of p (2, and M ₍₂ ). This この₍₂ > (β For example, there are autoregression, moving average, and autoregression moving average.

When the density of the polymerization reaction solution and the polymerization conversion rate of the polymerization reaction solution in the present invention are analyzed, the correlation coefficient of the calibration curve is 0.9 or more, preferably 0.95 or more, more preferably 0.9% or less. That is all.

The range of the polymerization conversion that can be measured by the method for measuring the polymerization conversion according to the present invention is not particularly limited as long as the change in the density of the polymerization reaction solution can be measured.

In the method for measuring the polymerization conversion rate according to the present invention, the calculated value of the polymerization conversion rate calculated by the method for measuring the polymerization conversion rate according to the present invention, and the amount or weight of the unreacted monomer actually calculated according to an ordinary method. It is possible to reduce the error (absolute value of the difference between the measured value and the measured value by the method of the present invention) from the measured value of the polymerization conversion obtained by measuring the amount of coalescence. Specifically, the difference between the calculated value and the actually measured value can be suppressed to an absolute value, preferably 2% or less, more preferably 1.5% or less, and particularly preferably 1% or less.

In addition, according to the method for measuring the polymerization conversion rate of the present invention, it is not necessary to collect the polymerization reaction solution and the like, and the density of the polymerization reaction solution is constantly measured. Since it is output as, it is input to a computer or the like, processed and output, so that the polymerization conversion can be obtained at the same time as the measurement.

In the method for producing a polymer according to the present invention, the polymerization reaction factor is changed according to the value of the polymerization conversion rate in the emulsion polymerization reaction solution calculated as described above.

The polymerization reaction factors include the presence or absence of additional introduction of monomer, polymerization initiator and other polymerization auxiliary materials as raw material supply elements, the timing and amount of additional addition; the reaction temperature as an emulsion polymerization element Controlling the flow rate of the refrigerant or heat medium, reaction pressure, polymerization reaction The stirring speed of the tank and the method of stirring the polymerization reaction tank; and the addition of a polymerization terminator as a polymerization termination element, cooling in the polymerization reaction tank, and depressurization in the polymerization reaction tank are exemplified. In the present invention, it is preferable that at least one selected from these polymerization reaction factors is appropriately selected and changed. By changing the various polymerization reaction factors as described above, the deviation from the target quality can be adjusted by changing the reaction conditions. In particular, during the period from the start of polymerization to the end of polymerization, at least one additional addition of monomer and / or polymerization initiator to the polymerization system (polymerization reaction tank) can adjust the polymerization conversion rate. It is effective for

The method of determining the amount that changes the polymerization reaction factor is not particularly controlled. For example, proportional control, proportional integral control, proportional integral derivative control, fuzzy control, adaptive control, etc. can be applied as the control algorithm.

In a batch (batch) type polymerization, the polymerization conversion of the polymerization reaction solution after the polymerization is measured in a short time, and the polymerization is performed as it is depending on whether it is within the target polymerization conversion. Ability to continue the reaction, or to continue the polymerization reaction after adding monomer and Z or polymerization initiator. \ After sending the polymerization reaction solution to the polymer separation / recovery process or to the waste process. It is also preferable to select and execute processing. By carrying out in this manner, when the polymerization is repeated until the required amount of the target polymer is obtained, the time during which the polymerization reaction is not performed inside the polymerization reactor can be shortened, and the production efficiency can be increased.

In the present invention, the present invention is not limited to batch polymerization, but may be applied to continuous polymerization. In the present embodiment, the polymerization conversion rate of the polymerization reaction solution is not directly measured, and the density of the polymerization reaction solution, which is a substitute property thereof, is measured using a vibrating densitometer. The value of the polymerization conversion rate of the polymerization reaction liquid is calculated from the above. Since the density of the polymerization reaction solution is measured by using a vibration densitometer, the density of the polymerization reaction solution can be obtained with a simple operation with high measurement accuracy and in a short time. In addition, since the vibratory densitometer is installed inside the polymerization reaction tank, the density of the polymerization reaction liquid can be measured inside the polymerization reaction tank without taking it out of the polymerization reaction tank. As a result, a polymer of the desired quality can be produced industrially advantageously without losing the end of the reaction. In the present invention, the "target quality" is not limited to the molecular viscosity, molecular weight, molecular weight distribution and the like of the polymer, but also refers to the production efficiency such as the yield of the polymer relative to the amount of the monomer used. Used in the sense of including. For example, the efficiency of utilization of production equipment when producing a polymer by multiple patch-type polymerizations, such as the time during which a polymerization reaction does not proceed in a polymerization reactor in a patch-type polymerization, is also included.

In order to realize the above-described method for producing a polymer according to the present invention, for example, a polymer production apparatus 300 having a configuration shown in FIG. 1 can be used. The following description exemplifies the case of emulsion polymerization.

As shown in FIG. 1, the production apparatus 300 has a polymerization reaction tank 1 for obtaining an emulsion polymerization reaction solution by an emulsion polymerization reaction. The polymerization reaction tank 1 has a line 200 to which deionized water 20 is supplied, a line 210 to which monomer 21 is supplied, and? A line 220 to which the W danger 22 is supplied, a line 230 to which the polymerization initiator 23 is supplied, a line 240 to which the cocatalyst 24 is supplied, and a molecular weight regulator 25 The supplied line 250 is connected. Lines 200, 210, 220, 230, 240, 250 are equipped with automatic control valves 2009, 219, 229, 239, 249, 2 5 9 are arranged. The automatic control valves 209 to 255 are provided to the polymerization reaction tank 1 based on the data sent from the flowmeters 208, 218, 228, 238, 248, 258. The degree of opening is adjusted to change the input amounts of deionized water 20, monomer 21, emulsifier 22, polymerization initiator 23, cocatalyst 24 and molecular weight regulator 25. The polymerization reaction tank 1 may be connected to another line (not shown) for supplying other polymerization auxiliary materials.

A temperature control member 29 is mounted around the polymerization reaction tank 1. The temperature control member 29 is connected to a line 260 to which a refrigerant or a heat medium 26 is supplied. In line 260, an automatic regulating valve 269 is arranged. The automatic regulating valve 269 is used to control the temperature of the polymerization reaction tank 1 based on the data sent from the thermometer 2667 based on the data from the thermometer 10 based on the data from the thermometer 10. In order to change the flow rate of the heating medium 26 and, as a result, to change the temperature in the polymerization reaction tank 1, the opening thereof is adjusted.

A pressure reduction degree adjustment line 280 is connected to the upper part of the polymerization reaction tank 1. Line 2 At 80, an automatic regulating valve 289 and a compressor 286 as pressure reducing means are arranged. The opening of the automatic regulating valve 289 is adjusted based on the data sent from the regulator 287 in order to change the degree of pressure reduction in the polymerization reactor 1.

A transfer tank 2 is connected to the polymerization reaction tank 1 through a line 70. The transfer tank 2 is connected to a line 270 to which a polymerization terminator 27 is supplied. On line 270, an automatic regulating valve 279 is arranged. The opening of the automatic adjusting valve 279 is adjusted based on data sent from the flow meter 278 in order to change the amount of the polymerization terminator 27 to be transferred to the transfer tank 2.

In the present embodiment, the configuration is such that the polymerization terminator 27 is charged into the transfer tank 2, but the present invention is not limited to this. The line 270 may be connected to the polymerization reaction tank 1, and the polymerization terminator 27 may be added to the emulsion polymerization reaction liquid in the polymerization reaction tank 1. Also, a polymerization terminator 27 is injected into the line 70 connecting the polymerization reaction tank 1 and the transfer tank 2, that is, while the emulsion polymerization reaction solution is being transferred from the polymerization reaction tank 1 to the transfer tank 2. It can be configured as

As shown in FIG. 3, the polymerization reaction tank 1 has a stirring means 11 for stirring the inside, and the emulsion polymerization reaction solution 21 in the reaction tank is used by the stirring means 11 from the start to the end of the polymerization. Stirring is possible so that the density of 1 is substantially uniform.

Further, a vibrating density meter 42 is mounted inside the polymerization reaction tank 1. The vibrating densitometer 42 is installed so that the vibrator 426 as a measuring terminal is immersed in the emulsion polymerization reaction liquid 211 to be obtained inside the polymerization reaction tank 1.

In the present embodiment, a tuning fork type vibratory density meter is used as the vibratory density meter 42. As shown in FIG. 4, the vibratory densitometer 42 used in the present embodiment is suspended and supported by a device main body (not shown) via a holding section 42. A pair of support members 424 are attached to the holding portion 422. A vibrator 426 as a measuring terminal is attached to the tip of each support member 424. Each support member 4 24 is provided with an electromagnetic drive unit (not shown) for vibrating the vibrator 4 26. The electromagnetic force generated in this electromagnetic drive unit (not shown) and the support member Due to the elasticity of 4 24, the vibrator 4 26 vibrates in the emulsion polymerization reaction liquid 2 11 (see FIG. 3). The vibrator 4 2 when immersed in the emulsion polymerization reaction solution 2 1 1 6, emulsion polymerization viscous resistance between the reaction liquid 21 1, oscillator ⁴ capable of detecting the displacement sensor 427 as a change in amplitude value of 26 is attached. A liquid level sensor (water level sensor) 425 for controlling the positional relationship between the density meter 42 and the liquid level of the emulsion polymerization reaction liquid 211 is attached to the holding portion 422 between the pair of support members 4 24, 424. There is. The liquid level sensor 425 is not particularly limited, and any type such as a light refractive index sensor type can be used.

As shown in FIG. 1 Oyopi Figure 3, the vibratory density meter 42, estimating arithmetic unit 5 as a polymerization conversion rate calculation unit Yes connected, here measured by the density meter ⁴ 2 The value of the polymerization conversion of the emulsion polymerization reaction liquid 211 is calculated from the value of the density of the emulsion polymerization reaction liquid 211. As the estimation calculation device 5, a computer device is usually used.

As shown in FIG. 1, a control operation device 6 as a factor changing means is connected to the estimation operation device 5, and the calculated value of the polymerization conversion calculated by the estimation operation device 5 is a predetermined output signal. Is input to the control arithmetic unit 6 as a factor changing means.

The control arithmetic unit 6 controls the flow meters 208, 218, 228, 238, 248, 258, 278 based on the output signal from the estimating arithmetic unit 5 and, by extension, automatically adjusts the valves 209, 219, 229, 239, 249, 259, 269, 279, 289.

Next, an operation of the manufacturing apparatus 300 according to the present embodiment will be described with reference to FIGS.

First, deionized water 20, monomer 21,? Automatic regulator valves 209, 21 9 controlled by the data from flow meters 208, 218, 228, 238, 248 and 258, respectively, of the L-agent 22, the polymerization initiator 23, the co-catalyst 24 and the molecular weight regulator 25. , 229, 239, 249, and 259, a certain amount is charged into the polymerization reaction tank 1 (raw material supply step), and emulsion polymerization is started.

In the present embodiment, as the monomer 21, unsaturated nitrile or aromatic biel and a conjugated diene are used.

As unsaturated nitriles, atarilonitrile; α-chloroatarylonitrile, _alpha - Puromoakuriro - A halogenoalkyl acrylonitrile such as tolyl; methacrylonitrile nitrile, ethacrylonitrile one _alpha such Arukiruakuriro - tolyl and the like. Among them, acryloetrile is preferred. These unsaturated nitriles may be used alone or in combination of two or more.

Examples of the aromatic butyl include styrene, -methylstyrene, o-methylstyrene, P-methylstyrene, pt-butylstyrene, 1,3-dimethylstyrene, biernaphthalene, and buranthracene. Of these, styrene is preferred. These aromatic butyls may be used alone or in combination of two or more.

Examples of the conjugated diene include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and 2,4-hexadiene. Of these, 1,3-butadiene and isoprene are preferred, and 1,3-butadiene is particularly preferred. These conjugated gens may be used alone or in combination of two or more.

From the start of polymerization to the end of polymerization, the flow rate of the refrigerant or heat medium 26 is adjusted by the automatic adjustment valve 26 9 controlled by the controller 26 7 based on the data from the thermometer 10. The temperature inside is adjusted (emulsion polymerization step). From the start to the end of the polymerization, stirring is performed by the stirring means 11 of the polymerization reaction tank 1 so that the density of the emulsion polymerization reaction liquid 211 in the reaction tank becomes substantially uniform.

According to the progress of the polymerization, after a lapse of a predetermined time from the start of the polymerization, the vibrating densitometer 4 2 provided so that the vibrator 4 26 as a measuring terminal is immersed in the emulsion polymerization reaction liquid 2 1 1. Measure the density. Specifically, by operating an electromagnetic drive unit (not shown), the vibrators 426 are oscillated in opposite phases and at the same cycle. At this time, the viscous resistance generated between the vibrator 4 26 arranged in the emulsion polymerization reaction liquid 2 11 and the emulsion polymerization reaction liquid 2 11 The density of the emulsion polymerization reaction liquid 211 is measured by detecting the change in the amplitude value of the liquid. Since a predetermined relationship is established between the amplitude value of the vibrator 4 26 and the viscous resistance, the change in the amplitude value is measured to measure the density of the emulsion polymerization reaction solution 2 11. Can be. Next, the value of the density of the emulsion polymerization reaction liquid 211 measured by the vibration type densitometer 42 is introduced as a predetermined output signal into the estimating arithmetic unit 5, and the value of the polymerization conversion is calculated. The calculated value of the polymerization conversion is sent to the control arithmetic unit 6 as a predetermined output signal. The control arithmetic unit 6 first compares the input value of the polymerization conversion with a preset target value of the polymerization conversion.

Next, based on the comparison results, the addition of the monomer 21, the polymerization initiator 23, and other polymer auxiliary materials (deionized water 20, lactic acid 22, co-catalyst 24, and molecular weight regulator 25) was added. Whether or not to add, timing and amount of additional charge (raw material supply element); flow rate of refrigerant or heating medium 26 that controls reaction temperature, reaction pressure, stirring speed of polymerization reactor 1 and stirring method of polymerization reactor 1 (emulsion polymerization elements); and polymerization terminator ² 7-on of the cooling and polymerization under reduced pressure in the reaction vessel 1 in the polymerization reaction vessel 1 (polymerization termination element); even without least selected from a control signal for changing one Generate Finally, the generated control signal is sent to the adjusters 207, 217, 227, 237, 247, 257, 267, 27

Transmit to at least one selected from 7 and 287.

The flowmeters 208, 218, 228, 2

Instruct 38, 248 and 258 to adjust the flow rate and automatically adjust the valve.

For 209, 219, 229, 239, 249, and 259, the opening degree is adjusted to be appropriate so that the determined additional components and the determined amount are additionally charged into the polymerization reaction tank 1. At this time, it is preferable to additionally add the monomer 21 and the polymerization initiator 23 at least once to the polymerization reaction tank 1 because it is effective in controlling the polymerization conversion ratio.

Upon receiving the signal, the regulator 267 adjusts the automatic opening of the automatic adjustment valve 269 to an appropriate degree so that the cooling medium or the heating medium 26 flows at an appropriate flow rate. Thereby, the temperature in the polymerization reaction tank 1 is adjusted.

When the predetermined polymerization conversion rate is reached, the emulsion polymerization reaction liquid is transferred to the transfer tank 2 based on the data from the control arithmetic unit 6.

Further, when the control signal generated by the control arithmetic unit 6 is sent to the regulator 277, the regulator 277 that has received the signal issues an instruction to adjust the flow rate by the flow meter 278, and sends an instruction to the automatic regulating valve 279. Transfer a certain amount of polymerization terminator 27 Adjust the opening to a proper value so that it can be inserted in 2. When a polymerization terminator 27 is charged into the transfer tank 2, the polymerization reaction is stopped (polymerization termination step).

If the processing device 6 determines that shortstop, in addition to the polymerization terminator 2 7 of the closing, the control signal generated by the control calculation unit 6, the degree of reduced pressure adjustment line ^{2 8} 0 to disposed the automatic regulating valve 2 The automatic control valve 289 receives this signal, opens the valve fully, activates the compressor 286, and draws the pressure inside the polymerization reaction tank 1 through the line 280 under reduced pressure. (Polymerization stopping step). The degree of pressure reduction at this time may be set so that the pressure (gauge pressure) in the polymerization reaction tank 1 is, for example, about 180 kPa or less. When the pressure in the polymerization reactor 1 is reduced to remove the monomers, the polymerization reaction stops. If the opening degree of the automatic control valve 26 is adjusted and the amount of the refrigerant 26 flowing in the temperature control member 29 is increased, the inside of the polymerization reaction tank 1 will be cooled (polymerization stop step). Can also stop the polymerization reaction.

Thereafter, the polymerization reaction tank 1 in which the polymerization has been stopped is washed and prepared so that the next polymerization can be performed.

In the present embodiment, an example has been described in which the polymerization terminator 27 is charged in the transfer tank 2.However, for example, when the transfer from the polymerization reaction tank 1 to the transfer tank 2 takes time, , A polymerization terminator 27 may be added.

The embodiments of the present invention have been described above. However, the present invention is not limited to these embodiments at all, and it is needless to say that the present invention can be implemented in various modes without departing from the gist of the present invention. .

For example, in the above-described embodiment, the value of the polymerization conversion rate of the polymerization reaction solution is calculated from the value of the density of the polymerization reaction solution measured using the vibration type densitometer, and the calculated value of the polymerization conversion rate is calculated. The polymerization reaction factor is changed accordingly. However, the present invention is not limited to this method, and the polymerization reaction factor may be changed according to the measured value of the density of the polymerization reaction solution. Because there is a predetermined correlation between the density of the polymerization reaction solution and the polymerization conversion rate of the polymerization reaction solution, the polymerization reaction factor is changed according to the value of the density of the polymerization reaction solution. This is because the same effect can be obtained, that is, a polymer having a desired quality can be industrially advantageously produced without losing the end of the reaction. In this case, the estimator 5 (see FIG. 1 or 3) and The step of calculating the polymerization conversion rate by the apparatus 5 can be omitted. In this case, the density data output from the vibrating density meter 42 is introduced into the control operation device 6 (see FIG. 1) of the device 300, and is used for subsequent control. Example

Hereinafter, the present invention will be described specifically with reference to Examples and Comparative Examples. Parts and percentages are by weight unless otherwise specified.

The actually measured polymerization conversion rate is a value obtained by drying the polymerization reaction solution and calculating the remaining solid content.

Example 1

A polymerization reactor with a tuning fork-type vibratory density meter installed so that a vibrator as a measuring terminal is immersed in the polymerization reaction solution

Deionized water 285 parts, acrylonitrile 50 parts, butadiene 50 parts, sodium dodecyl sulfate 3 parts, dodecyl mercaptan 0.35 parts, iron sulfate 0.1 parts Department and Cumenhai Dropbox 0.01 parts. The reaction was maintained at 10 ° C. with sufficient stirring so that the whole became uniform. Thereafter, the density of the polymerization reaction solution was measured at 10 points in accordance with the progress of the polymerization. Simultaneously with the measurement of the density, 0.01 parts of the polymerization reaction solution was sampled, and the measured polymerization conversion was measured.

Assuming that the measured polymerization conversion rate is y (%) and the density of the polymerization reaction solution is X (kg / m ³ ), the following correlation was found between X and y. The calibration curve (regression line) is shown in FIG. The black circles in FIG. 2 represent the data used to create the calibration curve.

y = 0.894 x-775. 1

(Correlation coefficient 0.998)

Example 2

After the calibration curve was prepared in Example 1, all the polymerization reaction liquid was taken out of the polymerization reaction tank, and after sufficiently washing the polymerization reaction tank, the polymerization reaction was performed in the same manner as in Example 1. Measures the density and automatically calculates the density based on the calibration curve of Example 1 The polymerization conversion was calculated. The polymerization conversion was checked every 20 minutes, and at the same time, 0.01 part of the polymerization reaction solution was sampled and analyzed to measure the actual polymerization conversion. Table 1 shows the density, the calculated polymerization conversion, the measured polymerization conversion, and the measurement error every 60 minutes and 560 minutes after the start of the polymerization. Six hundred and fifty minutes after the start of the polymerization, the density of the polymerization reaction liquid reached a value (951 kg Zm ³ ) corresponding to the desired polymerization conversion rate of 75%, so that 0.1 part of hydroxylamine sulfate was used. And 0.1 part of sodium hydroxide were added to stop the reaction. The measured polymerization conversion rate after the termination of the polymerization was 74%.

After all of the polymerization reaction liquid was taken out from the same polymerization reaction tank, polymerization was repeated without washing, the density was measured, and only the calculated polymerization conversion was obtained. In the fifth polymerization, the density of the polymerization reaction solution reached a value corresponding to the desired polymerization conversion rate of 75% in 60 minutes after the start of the polymerization. Therefore, the polymerization reaction was stopped in the same manner as in the first polymerization. The polymerization conversion was 75% and the error was 0. Observation of the support member 4 2 4 (see Fig. 4) of the densitometer showed that after the fifth polymerization, the polymer was located at the base of the protruding part of the densitometer compared to before the first polymerization. Was observed, but could be easily removed by simple washing. In addition, no adhesion of polymer was observed on the vibrator 42 6 (see FIG. 4), which is the measurement terminal.

Comparative Example 1

The polymerization reaction was carried out in the same manner as in Example 1. Every 20 minutes, 0.01 part of the polymerization reaction solution was sampled and analyzed, and the measured polymerization conversion was measured. The measurement took 20 minutes. Table 1 shows the measured polymerization conversion rate every 60 minutes and at 560 minutes after the start of polymerization. From the measured polymerization conversion rates (66%, 69%, 71%, respectively) of 540 minutes, 560 minutes and 580 minutes after the start of polymerization, the polymerization conversion rate was approximately 1%. It was assumed that it would take 8 minutes to ascend, and it was estimated that the target polymerization conversion rate of 75% was reached after 580 minutes and 32 minutes, that is, 612 minutes after the start of the polymerization. Immediately after collecting the sample for measuring the actual polymerization conversion for 600 minutes after the start of the polymerization, the above estimation is obtained, and the actual polymerization conversion is determined from the sample at the 600th minute. Canceled. The polymerization was stopped 61 minutes after the start of the polymerization. The measured polymerization conversion rate after the termination of the polymerization was 77%.

Comparative Example 2

Tuning fork-type vibrations in a 2-inch inner diameter circulation pipeline attached to the polymerization reactor A density meter is attached, the polymerization reaction liquid flows out of the polymerization reaction tank into the pipe, and after measuring the density, it flows back into the polymerization reaction tank. The same treatment as in Example 1 was conducted except that the density was measured with a meter. Assuming that the measured polymerization conversion rate is y (%) and the density of the polymerization reaction solution is X (kg / m ³ ), the following correlations were found between X and y, respectively.

y = 0.89 2 x- 7 7 6.4

(Correlation coefficient 0.998)

After taking out all the polymerization reaction liquid from the polymerization reaction tank and sufficiently washing the polymerization reaction tank, a polymerization reaction was performed in the same manner as in Example 1 using the above correlation as a calibration curve. The polymerization conversion was automatically calculated based on the calibration curve from the output of the densitometer. The polymerization conversion was checked every 20 minutes, and at the same time, 0.01 part was sampled and analyzed to measure the polymerization conversion. The polymerization conversion rate calculated from the densities measured at 60 and 580 minutes after the start of polymerization and at 60 and 580 minutes after the start of polymerization, the polymerization conversion rate obtained by analyzing the collected polymerization reaction solution, and the error between them are shown in the table. Shown in 1.

In addition, since the density of the polymerization reaction solution reached a value (954 kg / m ³ ) corresponding to the desired polymerization conversion rate of 75% in 605 minutes after the start of polymerization, 0.1 parts of hydroxylamine sulfate and hydroxyl were added. The reaction was stopped by adding 0.1 part of dig sodium. The measured polymerization conversion after the termination of the polymerization was 75%.

After all of the polymerization reaction solution was taken out from the same polymerization reaction tank, polymerization was repeated without washing, and only the density and the calculated polymerization conversion rate were determined. Each time the polymerization was repeated, the time required for the measured density to reach a value corresponding to the target polymerization conversion rate was prolonged, and the measured polymerization conversion rate after termination of the polymerization gradually increased from the target value. In the fifth polymerization, 650 minutes after the start of the polymerization, the density of the polymerization reaction solution reached a value corresponding to the desired polymerization conversion rate of 75%, and the polymerization was stopped. The measured polymerization conversion rate after the termination of the polymerization was 81%. After the fifth polymerization, the circulation pipeline was removed, and the degree of adhesion of the polymer was observed.As a result, almost no adhesion of the polymer was observed on the linear portion, but the curved portion and the root of the protruding portion of the density meter were observed. Considerable adhesion was observed. When the densitometer was removed and observed, no polymer adhered to the vibrator 426 (see Fig. 4) as the measuring terminal. 1

As shown in Comparative Example 1, it takes time to determine the polymerization conversion rate by analyzing the polymerization reaction solution, and it is difficult to stop the polymerization at the desired polymerization conversion rate.

Also, as shown in Comparative Example 2, when a density meter was installed in the circulating pipeline, if the washing was not repeated sufficiently, the density in the polymerization reaction tank would be instantaneously increased in the pipeline due to clogging of the pipe. And it is difficult to measure the density accurately. For this reason, the measurement accuracy of the polymerization conversion rate decreases, and it is difficult to stop the polymerization at the target polymerization conversion rate. If the pipeline is removed and washed every time, even if the washing is performed fairly quickly, it takes time to remove, assemble, check the safety, and so on. If continuous polymerization is performed, productivity will decrease.

In contrast, as shown in Example 2, according to the measurement method of the present invention, the density of the polymerization reaction solution in the polymerization reaction tank was measured using a tuning fork vibrating densitometer attached inside the polymerization reaction. After that, as in Example 1, the polymerization conversion rate is calculated by using a calibration curve created based on the density of the polymerization reaction solution previously measured by the method and the polymerization conversion rate actually measured. For this reason, the polymerization conversion can be measured immediately with high accuracy, and the error with the target polymerization conversion can be reduced, and the polymerization can be stopped. This effect is maintained even after repeated polymerization.

Claims

Claims 1. A step of measuring the density of the polymerization reaction liquid using a vibration type densitometer mounted inside the polymerization reaction tank;

Calculating the value of the polymerization conversion rate of the polymerization reaction solution from the measured density value.

2. The method for measuring polymerization conversion rate according to claim 1, wherein a tuning fork type vibratory density meter is used.

3. The method according to claim 1, wherein an emulsion polymerization reaction liquid is used as the polymerization reaction liquid.

4. The method for measuring the polymerization conversion rate according to claim 3, wherein an emulsion polymerization reaction solution of a copolymer composed of unsaturated nitrile or aromatic butyl and a conjugated diene is used.

5. a step of obtaining a polymerization reaction solution by a polymerization reaction;

6. a step of obtaining a polymerization reaction solution by a polymerization reaction;

7. The method for producing a polymer according to claim 5, wherein a tuning fork type vibratory density meter is used.

8. The polymerization reaction factor is at least one selected from a raw material supply element, a polymerization element and a polymerization termination element,

The raw material supply element is at least one selected from a monomer, a polymerization initiator, and other polymerization auxiliary materials, whether or not additional addition is performed, a timing of additional addition, and an additional input amount. A flow rate of a cooling medium or a heat medium for controlling a reaction temperature, a reaction pressure, a stirring speed of a polymerization reaction tank and a stirring method of a polymerization reaction tank, wherein the polymerization termination element is a polymerization termination agent, 7. The method for producing a polymer according to claim 5, wherein the method is at least one selected from cooling in a polymerization reaction tank and reduced pressure in the polymerization reaction tank.

9. A raw material supply step of supplying a raw material comprising a monomer, a polymerization initiator, and other polymerization auxiliary materials to a polymerization reactor;

A method for producing a polymer, comprising: a polymerization step of polymerizing a monomer in the polymerization reaction tank to obtain a polymerization reaction solution; and a polymerization termination step of terminating polymerization at a predetermined polymerization conversion rate.

The calculated value of the polymerization conversion rate of the polymerization reaction solution is transmitted to at least one step selected from the raw material supply step, the polymerization step, and the polymerization termination step, and the polymerization reaction factor in each step is changed. And a factor changing step.

10. A raw material supply step of supplying a raw material comprising a monomer, a polymerization initiator and other polymerization auxiliary materials to a polymerization reaction tank; A method for producing a polymer, comprising: a polymerization step of polymerizing a monomer in the polymerization reaction tank to obtain a polymerization reaction solution; and a polymerization termination step of terminating polymerization at a predetermined polymerization conversion rate.

Transmitting the measured density value to at least one step selected from the raw material supply step, the polymerization step, and the polymerization stop step, and changing a polymerization reaction factor in each step; A method for producing a polymer having

11. The calculated value of the polymerization conversion rate of the polymerization reaction solution is transmitted to the raw material supply step, and at least one selected from the presence / absence of additional input of each raw material, the timing of additional input, and the additional input amount. 10. The method for producing a polymer according to claim 9, which is varied.

12. The measured density value is transmitted to the raw material supply step, and at least one selected from the presence / absence of additional input of each raw material, the timing of additional input, and the additional input amount is changed. The method for producing a polymer according to the above.

13. The method for producing a polymer according to claim 11 or 12, wherein the monomer and / or the polymerization initiator are additionally added at least once to the polymerization reaction tank between the start of the polymerization and the termination of the polymerization.

14. The calculated value of the polymerization conversion rate of the polymerization reaction solution is transmitted to the polymerization termination step, and at least one selected from the addition of a polymerization terminator, the cooling in the polymerization reaction vessel, and the reduced pressure in the polymerization reaction vessel. 10. The method for producing a polymer according to claim 9, wherein the polymerization reaction is stopped by one of two methods.

15. The measured density value is transmitted to the polymerization stopping step, and the polymerization is stopped by at least one method selected from charging of a polymerization terminator, cooling in the polymerization reaction tank, and depressurization in the polymerization reaction tank. Production of the polymer according to claim 10, wherein the polymerization reaction is stopped. Method.

16. The method for producing a polymer according to claim 9 or 10, wherein unsaturated nitrile or aromatic vinyl and a conjugated diene are used as monomers.

17. A polymerization reaction tank for obtaining a polymerization reaction solution by a polymerization reaction,

A factor changing means for changing a polymerization reaction factor according to the value of the polymerization conversion rate of the polymerization reaction solution calculated by the polymerization conversion rate calculating means.

18. A polymerization reactor having a vibratory densitometer installed so that the measurement terminal is immersed in the polymerization reaction solution to be obtained inside.