JP2009270018A - Method for producing polymer particle and polymerization apparatus therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for polymer particles capable of controlling a polymerization rate to regulate grain sizes of the polymer particles to desired ones before a monomer polymerization ratio reaches 40%, and while keeping the grain sizes of the polymer particles to the desired ones after the monomer polymerization ratio exceeds 40%, changing the polymerization rate freely without any increase in emulsifying agent concentration for controlling monomer polymerization completion time. <P>SOLUTION: Before the monomer polymerization ratio reaches 40%, the polymer grain sizes are controlled to a target ones by regulating the polymerization rate based on polymerization temperature, polymerization initiator concentration and the like. After the monomer polymerization ratio exceeds 40%, while maintaining the grain sizes of the polymer particles constant to keep the target ones regardless of the polymerization rate, the monomer polymerization completion time is controlled by freely changing the polymerization rate without increasing the emulsifying agent concentration. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polymer particle production method for producing polymer particles by emulsion polymerization.

Conventionally, a production method for producing various polymer particles using an emulsion polymerization method has been proposed. For example, JP 2001-294603 A discloses a certain time from the start of continuous addition of a monomer, a catalyst and an emulsifier. After the lapse of time, the reaction heat at that time is measured, and the particle size of the product polymer is predicted from the reaction heat. If the predicted particle size of the product polymer is not within the predetermined range, the input amounts of the polymer, catalyst and emulsifier are set. A method for producing polymer particles in a semi-rotational emulsion polymerization process is described that adjusts the final particle size of the product polymer to a target value.
JP 2001-294603 A

However, in the method for producing polymer particles described in Patent Document 1, when the particle size of the produced polymer particles is increased, the emulsifier concentration is decreased to slow down the polymerization rate. When reducing the particle size of the polymer particles, it is necessary to increase the emulsifier concentration in order to increase the polymerization rate.
As described above, when the emulsifier concentration is increased to reduce the particle size of the polymer particles, impurities afterwards are contained due to the emulsifier, and as a result, the properties of the product polymer may be adversely affected. is there.

As a result of intensive studies on the problems of the prior art, the present inventors have carried out the emulsion polymerization of a monomer by emulsion-dispersing a reaction solution in which water, an emulsifier, a polymerization initiator and a monomer are mixed, and the polymerization rate of the monomer. Before reaching 40%, although there is a correlation between the polymerization conditions (polymerization temperature, polymerization initiator concentration) that determine the polymerization rate and the particle size of the polymer particles produced, the polymerization rate of the monomer is After exceeding 40%, it was discovered that the particle size of the polymer particles was maintained substantially constant irrespective of the polymerization conditions, and the present invention was achieved.
That is, the present invention was made to solve the above-mentioned problems of the prior art, and adjust the particle size of the polymer particles to a desired particle size by controlling the polymerization rate before the polymerization rate of the monomer reaches 40%. Then, the polymerization completion time of the monomer is controlled by freely changing the polymerization rate without increasing the emulsifier concentration while maintaining the particle size of the polymer particle at a predetermined particle size after the polymerization rate of the monomer exceeds 40%. It is an object of the present invention to provide a method for producing polymer particles.

  In order to achieve the above object, a method for producing polymer particles according to claim 1 is a method for producing polymer particles by emulsifying and dispersing a reaction liquid in which water, an emulsifier, a polymerization initiator and a monomer are mixed and emulsion polymerization of the monomers. In the production method, before the polymerization rate of the monomer reaches 40%, the polymer particle size of the polymer particles is set to a predetermined particle size by controlling the polymerization rate of the monomer, and the polymerization rate of the monomer exceeds 40%. Thereafter, the polymerization completion time of the monomer is controlled while maintaining the polymer particle size at a predetermined particle size.

  The polymer particle production method according to claim 2 is the polymer particle production method according to claim 1, wherein the viscosity of the reaction product is continuously measured as the emulsion polymerization proceeds, and the increase in the viscosity is substantially stopped and stabilized. At that time, it is judged that the monomer polymerization rate exceeds 40%.

  A polymerization apparatus according to claim 3 is a polymerization apparatus for producing a polymer particle by emulsifying and dispersing a reaction liquid in which water, an emulsifier, a polymerization initiator and a monomer are mixed and performing emulsion polymerization of the monomer. 2 polymerization rate setting means for setting the polymerization rate, polymerization rate detection means for detecting the polymerization rate of the monomer in the reaction solution, and before the polymerization rate of the monomer detected by the polymerization rate detection means reaches 40% The monomer is polymerized at the first polymerization rate set in the polymerization rate setting means to set the polymer particle size of the polymer particles to a predetermined particle size, and the polymerization rate of the monomer detected by the polymerization rate detection means exceeds 40%. Thereafter, the monomer polymerization is performed by switching from the first polymerization rate to the second polymerization rate, and the polymerization completion time of the monomer is controlled while maintaining the polymer particle size at a predetermined particle size. Characterized by comprising a means.

  The polymerization apparatus according to a fourth aspect is the polymerization apparatus according to the third aspect, wherein the polymerization rate detection means includes a viscosity measurement means that measures the viscosity of the reaction liquid while being immersed in the reaction liquid, and the control means includes The polymerization rate of the monomer is determined to be 40% or less while the viscosity of the reaction liquid measured through the viscosity measuring means is increasing as the polymerization of the monomer proceeds, and the viscosity measuring means is used. When the increase in the viscosity of the reaction solution measured in this step is substantially stopped and stabilized, it is judged that the monomer polymerization rate exceeds 40%.

  In the polymer particle manufacturing method according to claim 1, before the polymerization rate of the monomer reaches 40%, the polymer particle size of the polymer particle is set to a predetermined particle size by controlling the polymerization rate, and the polymerization rate of the monomer is 40%. Since the polymer particle size is kept constant regardless of the polymerization rate, the polymerization rate is controlled before the polymerization rate of the monomer reaches 40%. If the polymerization rate of the monomer exceeds 40%, the polymerization rate can be freely changed without increasing the emulsifier concentration while maintaining the particle size of the polymer particles at a predetermined particle size. It is possible to control the completion time.

  In the method for producing polymer particles according to claim 2, the viscosity of the reaction product is continuously measured as the emulsion polymerization proceeds, and when the increase in viscosity is substantially stopped and stabilized, the monomer polymerization rate is 40%. Therefore, it is possible to determine when the polymerization rate of the monomer reaches 40% based on the change in viscosity of the reaction solution.

  In the polymerization apparatus according to claim 3, before the polymerization rate of the monomer detected by the polymerization rate detection unit reaches 40%, the monomer is polymerized at the first polymerization rate set by the polymerization condition setting unit. After the polymer particle size is set to a predetermined particle size and the polymerization rate of the monomer detected by the polymerization rate detection means exceeds 40%, the polymer particle size is kept constant regardless of the polymerization rate. If the particle size of the polymer particles is adjusted to the desired particle size by controlling to the first polymerization rate before the monomer polymerization rate reaches 40%, the particle size of the polymer particles is increased after the monomer polymerization rate exceeds 40%. While maintaining the diameter at a predetermined particle diameter, the polymerization completion time of the monomer can be controlled by changing the polymerization rate to the second polymerization rate without increasing the emulsifier concentration.

  In the polymerization apparatus according to claim 4, the polymerization rate of the monomer is 40% or less while the viscosity of the reaction liquid measured through the viscosity measurement unit is rising as the polymerization of the monomer proceeds through the control unit. It is determined that the polymerization rate of the monomer exceeds 40% when the increase in the viscosity of the reaction liquid measured through the viscosity measuring means is substantially stopped and stabilized. It becomes possible to judge the point of time when the polymerization rate reaches 40% based on the change in viscosity of the reaction solution.

Hereinafter, the polymer particle manufacturing method according to the present invention will be described based on embodiments embodying the present invention.
The emulsion polymerization system used in the present embodiment is composed of a reaction liquid obtained by mixing water, an emulsifier, a polymerization initiator, and a monomer.
Here, sodium lauryl sulfate or ammonium lauryl sulfate is used as the emulsifier. As the polymerization initiator, a water-soluble peroxide such as ammonium persulfate, potassium or hydrogen peroxide, or a water-soluble azo compound having an amine hydrochloride as a water-soluble segment is used.

  As the monomer, 50 to 100 parts by weight of 2-hexyl acrylate and / or butyl acrylate and 0 to 50 parts by weight of acrylic acid are used.

  Each compound constituting the above-described emulsion polymerization system is emulsified and dispersed by an emulsification dispersion mixer, and the entire amount of the obtained mixture is charged into a reaction vessel. Then, the polymerization reaction of the monomer is performed with the polymerization initiator in a nitrogen atmosphere while stirring.

  Here, in the emulsion polymerization system, when the polymerization rate of the monomer is changed in the range from 0% to 40%, the polymerization rate of the monomer and the polymer particle size of the polymer particles to be polymerized I examined the relationship. The result is shown in FIG. FIG. 1 is a graph showing the relationship between monomer polymerization rate (% / min) and polymer particle size (median diameter (μm)) when the monomer polymerization rate is in the range of 0% to 40%.

  In FIG. 1, the horizontal axis indicates the polymerization rate (% / min), the vertical axis indicates the median diameter (μm) of the polymer particles, and as can be understood from the graph G1 obtained by extrapolating each plot in FIG. When the polymerization rate of the monomer is in the range of 0% to 40%, the smaller the monomer polymerization rate, the larger the polymer particle size. On the other hand, the higher the monomer polymerization rate, the smaller the polymer particle size. Thus, when the monomer polymerization rate is in the range of 0% to 40%, there is a clear correlation between the polymerization rate of the monomer and the polymer particle size.

  Further, when the relationship between the polymerization rate (%) of the monomer and the particle size of the polymer was examined, the result shown in FIG. 2 was obtained. FIG. 2 is a graph showing the relationship between the monomer polymerization rate (%) and the polymer particle size (median diameter (μm)) when the monomer polymerization rate is in the range of 0% to 100%.

  In FIG. 2, the horizontal axis represents the polymerization rate (%), the vertical axis represents the median diameter (μm) of the polymer particles, and the polymer particle size is shown in graph G2 obtained by extrapolating each plot in FIG. When the polymerization rate of the monomer is in the range of 0% to 40%, it gradually decreases as the polymerization rate increases, and becomes a substantially constant value after the polymerization rate exceeds 40%.

  Furthermore, after the polymerization rate of the monomer exceeded 40%, the polymerization rate of the monomer was changed, and it was investigated whether the change in the polymerization rate would affect the polymer particle size. The results are shown in FIGS. FIG. 3 is a graph showing a change state of the polymerization rate when polymerization is performed at three polymerization rates after the polymerization rate of the monomer exceeds 40%, and FIG. 4 is a change in the polymer particle size corresponding to the three polymerization rates. It is a graph which shows.

In FIG. 3, the horizontal axis represents time (min), and the vertical axis represents the polymerization rate (%). Graph G3 is a polymerization rate change curve when 0.07 parts by weight of the polymerization initiator is added and the polymerization temperature is maintained at 50 ° C., and graph G4 is 0.07 parts by weight of the polymerization initiator and the polymerization temperature is It is a polymerization rate change curve when the polymerization rate is reduced by lowering from 50 ° C. to 48 ° C. at 45 min, and graph G5 shows a polymerization temperature of 50 at 45 min by adding 0.07 part by weight of a polymerization initiator. It is a polymerization rate change curve at the time of making it reduce from 40 degreeC to 40 degreeC, and making polymerization rate still smaller.
The rate of increase of the polymerization rate with respect to time is greatest in the graph G3 where the polymerization temperature is the highest and the polymerization rate is large, and then in the order of the graph G4 and the graph G5 in descending order of the polymerization rate based on the polymerization temperature.

In FIG. 4, the horizontal axis represents frequency (%), the vertical axis represents particle size (μm), graph G6 represents a change in polymer particle size corresponding to graph G3, and graph G7 represents a change in polymer particle size corresponding to graph G4. Graph G8 shows the change in the polymer particle size corresponding to Graph 5.
Each of the graphs G6, G7, and G8 shows a dispersion state in which the polymer particle size is substantially the same, and the value thereof is also a substantially constant value. This means that after the polymerization rate of the monomer exceeds 40%, the polymer particle size of the polymer particles becomes a substantially constant value even when the polymerization rate is changed. Therefore, by adjusting the polymerization rate based on the polymerization temperature, the concentration of the polymerization initiator, etc. before the polymerization rate of the monomer reaches 40%, the polymerization rate of the monomer exceeds 40%. Even if the polymerization rate is changed after that, the polymer particle size is maintained at a substantially constant value. Therefore, the total polymerization time can be controlled by adjusting the polymerization rate freely after the monomer polymerization rate exceeds 40%. can do.

Further, in order to grasp the point in time when the polymerization rate of the monomer exceeded 40%, the relationship between the polymerization rate of the monomer and the viscosity of the reaction solution was examined. The result is shown in FIG. FIG. 5 is a graph showing the relationship between the polymerization rate of the monomer and the viscosity of the reaction solution.
As shown in graph G9 obtained by extrapolating each plot in FIG. 5, the viscosity of the reaction solution gradually increases until the monomer polymerization rate is up to 20%, and when the polymerization rate exceeds 20%, the viscosity is It rises rapidly. The viscosity exhibits a substantially constant value after the polymerization rate exceeds 40% and reaches 80%, and increases rapidly after the polymerization rate exceeds 80%.
Thus, when the polymerization rate exceeds 40%, the increase in viscosity stops and shows a constant value. Therefore, the viscosity of the reaction solution is continuously monitored, and when the polymerization rate becomes substantially constant, the polymerization rate becomes 40%. % Can be grasped.

Considering the facts described above, various polymerization controls can be performed in the emulsion polymerization system. Hereinafter, as an example, two polymerization control methods will be described with reference to FIGS.
First, before the polymerization rate of the monomer reaches 40%, the polymerization rate is controlled so that the polymer particle size becomes a desired value. After the polymerization rate exceeds 40%, the polymerization rate is increased. The case where the total polymerization time is controlled by changing will be described with reference to FIGS. FIG. 6 is a graph showing the change in the polymerization rate with respect to time in the two polymerization processes, and FIG. 7 is a graph showing the change in the polymer particle diameter in the two polymerization processes.

In FIG. 6, the horizontal axis represents time (min), the vertical axis represents the polymerization rate (%), and the graph G10 shows the polymerization rate of the monomer at a constant polymerization rate before reaching the polymerization rate of 40%. The change in the polymerization rate when the polymerization is carried out while maintaining the polymerization temperature at a constant temperature (for example, 50 ° C.) after exceeding 40% is shown.
Further, the graph G11 performs the polymerization reaction of the monomer at the same polymerization rate as in the graph G10 before reaching the polymerization rate of 40%, and after the polymerization rate exceeds 40%, the polymerization temperature is kept at a constant temperature (for example, 50 ° C. ), The change in the polymerization rate when the polymerization rate is reduced is shown.

  Here, in the case of graph G10, the polymerization reaction is completed in about 120 minutes from the start of polymerization, but in the case of graph G11, the polymerization rate is decreased after the polymerization rate exceeds 40%. The polymerization reaction time requires about 190 min.

In FIG. 7, the horizontal axis represents the particle size (μm), the vertical axis represents the frequency (%), the graph G12 represents a change in the polymer particle size corresponding to the graph G10, and the graph G13 represents the polymer particle size corresponding to the graph G11. Shows changes.
Each of the graphs G12 and G13 shows a dispersion state in which the polymer particle diameter is substantially the same, and the value thereof is also a substantially constant value.

  As described above, if the polymer particle size is controlled by adjusting the polymerization rate based on the polymerization temperature, the polymerization initiator concentration, etc. before the monomer polymerization rate reaches 40%, the monomer polymerization rate is 40%. Even if the polymerization rate is changed after exceeding 50%, the polymer particle size is maintained at a substantially constant value. Therefore, by adjusting the polymerization rate freely after the monomer polymerization rate exceeds 40%, the total polymerization is achieved. You can control the time.

  Next, before the polymerization rate of the monomer reaches 40%, the polymerization rate is changed to change the polymer particle size and the polymerization is performed to a desired value, and after the polymerization rate exceeds 40%, The case where the total polymerization time is controlled to be the same while keeping the polymerization rate constant will be described with reference to FIGS. FIG. 8 is a graph showing the change in the polymerization rate with respect to time in the two polymerization processes, and FIG. 9 is a graph showing the change in the polymer particle diameter in the two polymerization processes.

In FIG. 8, the horizontal axis represents time (hour), the vertical axis represents the polymerization rate (%), and the graph G14 lowers the dissolved oxygen concentration to carry out the monomer polymerization reaction at a constant polymerization rate. It shows the change in the polymerization rate when the polymerization is carried out while maintaining the polymerization temperature at a constant temperature (for example, 50 ° C.) after exceeding%.
Graph G15 shows the polymerization reaction of the monomer at a lower polymerization rate than in the case of graph G14 by adding the polymerization initiator concentration after increasing the dissolved oxygen concentration and reaching 30% before the polymerization rate reaches 40%. The change in the polymerization rate when the polymerization is carried out while maintaining the polymerization temperature at a constant temperature (for example, 50 ° C.) after the polymerization rate exceeds 40% is shown.

  Here, in the case of the graph G14, a polymer particle size corresponding to a certain polymerization rate is obtained before the polymerization rate reaches 40%, but in the case of the graph G15, the polymerization rate before the polymerization rate reaches 40%. Since the polymerization rate is small, a polymer particle size larger than that in the case of graph G14 is obtained. When the polymerization rate reaches around 40%, the two become substantially the same. Thereafter, the polymerization is carried out at the same polymerization rate, and the total polymerization time becomes the same.

In FIG. 9, the horizontal axis represents the particle size (μm), the vertical axis represents the frequency (%), the graph G16 represents the change in the polymer particle size corresponding to the graph G14, and the graph G17 represents the polymer particle size corresponding to the graph G15. Shows changes.
In the graph G16, the polymer particle size is small because the polymerization rate is large as described above. On the other hand, in the graph G17, the polymer particle size is large because the polymerization rate is small.
Thus, the total polymerization time can be controlled to be the same while changing the polymer particle size.

Then, the superposition | polymerization apparatus which performs the above-mentioned emulsion polymerization method automatically is demonstrated.
First, a schematic configuration of the polymerization apparatus will be described with reference to FIG. FIG. 10 is an explanatory view schematically showing a schematic configuration of the polymerization apparatus.
In FIG. 10, a polymerization apparatus 1 is charged into a stirring tank 2 via a supply tank 3 and a stirring tank 2 for synthesizing a polymer from a monomer mixture (reaction liquid) formed by mixing water, an emulsifier, a polymerization initiator, and a monomer. Into the operation unit 5 for inputting and setting various production conditions such as the temperature in the stirring tank 2 at the time of polymer production, the input amount of the polymerization initiator, etc. The controller 3 is provided with a controller 6 that controls the supply device 3 based on the various manufacturing conditions input and set to control the amount of polymerization initiator charged into the agitation tank 2 and controls the entire polymerization device 1.

In the stirring tank 2, a temperature sensor 7 for detecting the temperature of the monomer mixture in the stirring tank 2 and a viscosity sensor 8 for constantly detecting the viscosity of the monomer mixture are disposed. The temperature sensor 7 and the viscosity sensor 8 are connected to the control unit 6, and temperature data and viscosity data detected by the temperature sensor 7 and the viscosity sensor 8 are input to the control unit 6. A stirring blade 11 that is rotated around the rotation shaft 10 via a motor 9 is disposed in the stirring tank 2. Furthermore, a condenser 12 is disposed in the stirring tank 2.
The initiator storage tank 4 stores a predetermined amount of a polymerization initiator obtained in advance through experiments.

As will be described later, from the operation unit 5, when the polymerization rate of the monomer is 40% or less (hereinafter referred to as the first polymerization period), the correlation between the initiator concentration and the polymer particle size, the polymerization rate of the monomer is 40%. Polymerization rate formula when exceeding (hereinafter referred to as polymerization late), basic polymerization conditions (polymerization temperature, initiator concentration, monomer charge), upper and lower limits of polymerization temperature, target polymer particle size, target polymerization in late polymerization Various polymerization condition data such as speed (% / min) are input.
Various polymerization condition data input from the operation unit 5 is stored in a memory attached to the control unit 6.

  Moreover, the jacket 13 is attached to the stirring tank 2 so that the outer wall may be coat | covered. A pipe 14 is connected to an inlet formed below the jacket 13, and an inlet side temperature sensor 15, a heat exchanger 16, and a pump 17 are interposed in the pipe 14.

A pipe 18 is connected to an outlet formed above the jacket 13, and an outlet-side temperature sensor 19 and two electromagnetic valves 20 and 21 are interposed in the pipe 18. The electromagnetic valve 21 is connected to the pump 17 via a pipe 25. A dedicated chiller 22 is connected to the electromagnetic valve 21, and factory circulating water is supplied to the dedicated chiller 22 through a supply pipe 23. The dedicated chiller 22 is connected to the pump 17 via a pipe 24.
The inlet side temperature sensor 15 and the outlet side temperature sensor 19 are both connected to the control unit 6, and temperature data detected by the inlet side temperature sensor 15 and the outlet side temperature sensor 19 are input to the control unit 6. Is done.

The factory circulating water supplied from the supply pipe 23 is cooled by the dedicated chiller 22, and the cooling water is supplied to the jacket 13 through the pipe 24, the pump 17, and the heat exchanger 16. The stirring tank 2 is cooled by the cooling water supplied to the jacket 13. The temperature of the cooling water supplied to the jacket 13 is detected via the inlet side temperature sensor 15, and the detected temperature data is input to the control unit 6.
The cooling water supplied to the jacket 13 circulates in the jacket 13 through a circulation path that passes through the pipe 18, the electromagnetic valve 20, the pipe 25, the pump 17, and the like. The temperature of the circulating cooling water is detected via the outlet side temperature sensor 19, and the detected temperature data is input to the control unit 6.
In addition, when raising the temperature of the number of coolings, the heat exchanger 16 is actuated and the cooling water is heated.

このように得られた相関式は、制御部６のメモリに記憶される。 Here, a correlation equation between the initiator concentration and the polymer particle diameter in the first polymerization period will be described with reference to FIG. FIG. 11 is a graph showing the correlation between initiator concentration and polymer particle size.
Such a correlation equation is obtained by conducting an experiment in advance, plotting the relationship between the initiator concentration (wt%) and the polymer particle size (μm) obtained by the experiment as shown in FIG. 11, and extrapolating each plot to correlate. Find the formula. The particle diameter of the polymer is expressed by the following equation 1 using the correlation equation thus obtained.

The correlation equation thus obtained is stored in the memory of the control unit 6.

Next, the polymerization rate equation in the latter stage of polymerization will be described with reference to FIG. FIG. 12 is a graph showing the relationship between the reaction rate constant and the temperature obtained by performing the Arrhenius plot.
First, the polymerization rate equation in the latter stage of the emulsion polymerization is represented by the following formula 2 based on the Smith-Ewart theory.

  When the relationship between the reaction rate constant and the temperature is obtained by performing an Arrhenius plot for Equation 2, as shown in FIG. 12, lnk = −4810.7 / T + 13.037 and k = exp (−4810. 7 / T + 13.037). From this, the reaction rate constant k is expressed as y = −4810.7x + 13.037.

また、半減期については下記数４のように表される。

従って、前記した数２は、以下数５のように表される。

Further, the initiator concentration [I] is expressed as the following equation 3 as a function of the time t, the temperature T, and the initial initiator concentration [I0].

Further, the half-life is represented by the following formula 4.

Therefore, the above-described Expression 2 is expressed as Expression 5 below.

  Next, a procedure for automatically polymerizing a polymer from a monomer in the polymerization apparatus 1 configured as described above will be described with reference to FIGS. 13 and 14. 13 and 14 are flowcharts of a polymerization control procedure when polymerizing a polymer in the polymerization apparatus.

First, in step (hereinafter abbreviated as S) 1, the upper and lower limits of the polymerization temperature, basic polymerization conditions (polymerization temperature, initiator concentration, monomer charge), and the polymerization determined as described above. The correlation equation (Equation 1) between the initiator concentration and the polymer particle diameter in the first period and the polymerization rate equation (Equation 5) in the latter polymerization period are input via the operation unit 5 and stored in the memory of the control unit 6.
Here, for the initiator concentration and the polymer particle diameter in the pre-polymerization period, the center values obtained when the above-mentioned formulas 1 and 2 were obtained (in this embodiment, the initiator concentration: 0.015 [wt%], the polymerization temperature: 45 ° C.).
In addition, regarding the range of the upper limit and the lower limit value of the polymerization temperature, the upper limit value and the lower limit value of the experimental conditions used for obtaining the above formulas 1 and 2, or when the relationship between the product characteristics and the polymerization temperature is remarkable The polymerization temperature range required to meet the product properties is used.

  In subsequent S <b> 2, the operator inputs the target polymer particle size and the target polymerization rate (% / min) in the later stage of polymerization via the operation unit 5 and stores them in the memory of the control unit 6.

  In S3, the initial initiator concentration I0 for obtaining the target polymer particle size is calculated from the correlation equation represented by Equation 1. In S4, the temperature rise is started through the jacket 13 or the like so that the reaction liquid in the stirring tank 2 becomes 45 ° C. based on the basic polymerization conditions.

  In S5, the initiator amount satisfying the initial initiator concentration I0 is calculated from the monomer charge amount, and (I0 × charge amount) is charged into the stirring tank 2. In S6, the initial viscosity value μi of the reaction liquid detected through the viscosity sensor 8 when the initiator is charged and the initiator charging time ti are recorded in the memory. During the polymerization reaction, the viscosity of the reaction solution is monitored via the viscosity sensor 8.

In S7, it is determined whether or not the detected viscosity μ is equal to or greater than 4 × the initial viscosity value μi (μ ≧ 4 μi), and the value of the detected viscosity μ is stable (time change of μ≈0). Specifically, it is determined whether μ ≧ 4 μi and whether the difference is 5% or less compared to the value of μ one minute ago. When μ ≧ 4 μi and the difference is 5% or less compared to the value of μ one minute ago, the monomer polymerization rate reaches 40% as described in FIG. It is judged that
If the determination in S7 is NO (S7: NO), the process waits until the condition is satisfied. On the other hand, when the determination in S7 is YES (S7: YES), the initiator charging time is recorded as t1, and various polymerization conditions in the late polymerization period are set by the processing and determination in S9 to S17.

  Regarding the setting of the polymerization conditions in the later stage of polymerization, as shown in FIG. 14, first, in S8, the residual initiator concentration [It] at the time when the determination in S7 is YES is obtained using Equations 3 and 4. It is done. Specifically, it is obtained by substituting I0 obtained in Equation 1 for the time t (t1-ti), the temperature T for 45 ° C., and the initial initiator concentration.

  In the subsequent S9, [It] is substituted for [I0] in the polymerization rate equation (Equation 5) in the latter stage of polymerization, and in S10, the target polymerization rate is assigned to -d [M] / dt, and the residual monomer concentration ( Since the polymerization rate is 40%, it is calculated that 60% of all charged monomers remain), and the polymerization temperature T1 [K] required in the later stage of polymerization that satisfies these is calculated. .

In S11, it is determined whether the required temperature T1 is within the range between the upper limit value and the lower limit value of the polymerization temperature. If the determination is YES (S11: YES), it is output to the control unit 6 as the required temperature T1 required in the later stage of polymerization in S12. Thereafter, the process proceeds to S17.
On the other hand, if the determination in S11 is NO (S11: NO), it is determined in S13 whether the required temperature T1 is equal to or higher than the allowable upper limit temperature. If the determination in S13 is NO (S13: NO), the allowable lower limit temperature is output to the control unit 6 as the required temperature T1 in S14. Thereafter, the process proceeds to S17.

  On the other hand, if the determination in S13 is YES (S13: YES), the allowable upper limit temperature value and the required temperature T1 are substituted in Equation 5 in S15, and the initiator concentration required in the later stage of polymerization is calculated. The Thereafter, in S16, an initiator amount obtained by subtracting the amount of initiator already consumed ([It] × monomer charge amount) from the initiator concentration required in the later stage of polymerization is set as an initiator amount to be added in the later stage of polymerization, and The allowable upper limit temperature is output to the control unit 6 as the required temperature T1 required in the later stage of polymerization. Thereby, the amount of initiator is corrected when the required temperature is equal to or higher than the allowable upper limit temperature. Thereafter, the process proceeds to S17.

  In S17, the temperature of the stirring tank 2 is adjusted via the jacket 13 or the like based on the required temperature in the late polymerization stage obtained above. Furthermore, in S18, the polymerization reaction of the monomer proceeds in accordance with the polymerization conditions in the later stage of polymerization determined as described above.

  As described above in detail, in the polymer particle production method according to the present embodiment, before the polymerization rate of the monomer reaches 40%, the polymer particle size is adjusted by adjusting the polymerization rate based on the polymerization temperature, the polymerization initiator concentration, and the like. After the target particle size is controlled and the polymerization rate of the monomer exceeds 40%, the polymer particle size is kept constant regardless of the polymerization rate, so the polymerization is performed before the polymerization rate of the monomer reaches 40%. If the particle size of the polymer particles is adjusted to the desired particle size by controlling the speed, the emulsifier concentration is increased while maintaining the particle size of the polymer particles at the target particle size after the polymerization rate of the monomer exceeds 40%. The polymerization completion time can be controlled by freely changing the polymerization rate without doing so.

  In addition, the viscosity of the reaction product is continuously measured as the emulsion polymerization progresses, and when the increase in viscosity is substantially stopped and stabilized, it is determined that the monomer polymerization rate exceeds 40%. It becomes possible to judge the point of time when the polymerization rate reaches 40% based on the change in viscosity of the reaction solution.

  Furthermore, in the polymerization apparatus 1 according to this embodiment, while the viscosity value of the reaction liquid detected through the viscosity sensor 8 is increasing, it is determined that the monomer polymerization rate is 40% or less, and various The monomer is polymerized at a polymerization rate determined by the polymerization conditions (S1 to S4), the polymer particle size of the polymer particles is set to the target particle size, and the viscosity value of the reaction liquid detected via the viscosity sensor 8 It is judged that the polymerization rate of the monomer has exceeded 40% at the time when the increase in the temperature is stable and stable (S7: YES), and thereafter, the polymer particle size is kept constant regardless of the polymerization rate. Therefore, if the polymer particle size is adjusted to the target particle size by controlling to a desired polymerization rate before the monomer polymerization rate reaches 40%, the polymer particle after the monomer polymerization rate exceeds 40%. The particle size of the eyes While maintaining the particle size, the rate of polymerization without increasing the emulsifier concentration was variously changed and it is possible to control the polymerization completion time of the monomer.

  In addition, while the viscosity of the reaction liquid measured through the viscosity sensor 8 increases as the polymerization of the monomer proceeds, it is determined that the polymerization rate of the monomer is 40% or less. Since the polymerization rate of the monomer is determined to have exceeded 40% when the increase in the measured viscosity of the reaction solution is substantially stopped and stabilized, the viscosity of the reaction solution is determined when the polymerization rate of the monomer reaches 40%. Judgment can be made based on the change.

  Note that the present invention is not limited to the above-described embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.

It is a graph which shows the relationship between the polymerization rate (% / min) of a monomer in the range whose polymerization rate of a monomer is 0%-40%, and a polymer particle size (median diameter (micrometer)). It is a graph which shows the relationship between the polymerization rate (%) of a monomer in the range of 0%-100% of a monomer, and a polymer particle size (median diameter (micrometer)). It is a graph which shows the change state of the polymerization rate when superposing | polymerizing at three polymerization rates, after the polymerization rate of a monomer exceeds 40%. It is a graph which shows the change of the polymer particle size corresponding to three polymerization rates. It is a graph which shows the relationship between the polymerization rate of a monomer, and the viscosity of a reaction liquid. It is a graph which shows the change of the polymerization rate with respect to time in two polymerization processes. It is a graph which shows the change of the polymer particle size in two polymerization processes. It is a graph which shows the change of the polymerization rate with respect to time in two polymerization processes. It is a graph which shows the change of the polymer particle size in two polymerization processes. It is explanatory drawing which shows typically schematic structure of a superposition | polymerization apparatus. It is a graph which shows the correlation of an initiator density | concentration and a polymer particle size. It is a graph which shows the relationship between the reaction rate constant calculated | required by performing Arrhenius plot, and temperature. It is a flowchart of the superposition | polymerization control procedure at the time of superposing | polymerizing a polymer with a superposition | polymerization apparatus. It is a flowchart of the superposition | polymerization control procedure at the time of superposing | polymerizing a polymer with a superposition | polymerization apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Polymerization apparatus 2 Stirrer tank 4 Initiator storage tank 5 Operation part 6 Control part 8 Viscosity sensor 13 Jacket

Claims (4)

In the polymer particle production method of producing a polymer particle by emulsifying and dispersing a reaction solution in which water, an emulsifier, a polymerization initiator and a monomer are mixed, and performing emulsion polymerization of the monomer,
Before the polymerization rate of the monomer reaches 40%, the polymer particle size of the polymer particles is set to a predetermined particle size by controlling the polymerization rate of the monomer,
After the polymerization rate of the monomer exceeds 40%, the polymerization completion time of the monomer is controlled while maintaining the polymer particle size at a predetermined particle size. As the emulsion polymerization proceeds, the viscosity of the reactant is continuously measured,
2. The method for producing polymer particles according to claim 1, wherein the monomer polymerization rate is determined to have exceeded 40% when the increase in viscosity is substantially stopped and stabilized. 3. In a polymerization apparatus for producing polymer particles by emulsifying and dispersing a reaction liquid in which water, an emulsifier, a polymerization initiator and a monomer are emulsified and dispersed,
A polymerization rate setting means for setting the first polymerization rate and the second polymerization rate;
A polymerization rate detection means for detecting the polymerization rate of the monomer in the reaction solution;
Before the polymerization rate of the monomer detected by the polymerization rate detection means reaches 40%, the monomer is polymerized at the first polymerization rate set by the polymerization rate setting means to determine the polymer particle size of the polymer particles. After the polymerization rate of the monomer detected by the polymerization rate detection means exceeds 40%, the monomer polymerization is performed by switching from the first polymerization rate to the second polymerization rate to maintain the polymer particle size at a predetermined particle size. And a control means for controlling the completion time of the polymerization of the monomer. The polymerization rate detecting means includes a viscosity measuring means for measuring the viscosity of the reaction liquid while being immersed in the reaction liquid,
The control means determines that the polymerization rate of the monomer is 40% or less while the viscosity of the reaction liquid measured through the viscosity measurement means is increasing as the polymerization of the monomer proceeds, 4. The polymerization apparatus according to claim 3, wherein the polymerization rate of the monomer is determined to have exceeded 40% when the increase in the viscosity of the reaction solution measured through the measuring means is substantially stopped and stabilized. .

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