JP2003268035A - Method for producing emulsion polymerization polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently producing an emulsion polymerization polymer by suppressing reduction of productivity due to foaming of a surfactant used in the emulsion polymerization. <P>SOLUTION: The method for producing the emulsion polymerization polymer is to add a coagulant to a polymer latex obtained by emulsion polymerization using the surfactant, coagulate the polymer included in the polymer latex to be a slurry, dewater the slurry and dry the dewatered product. A defoaming agent is added to the polymer latex in 0.01-2.0 pts. mass based on 100 pts. mass polymer latex. Or, the defoaming agent is added to waste liquid generated by dewatering the polymer slurry and sent to a waste water treatment process in 0.01-2.0 pts. mass based on 100 pts. mass waste liquid. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an emulsion-polymerization polymer, and more specifically, it suppresses a decrease in productivity due to foaming of a surfactant used for emulsion-polymerization, and efficiently obtains an emulsion-polymerization polymer. The present invention relates to a method for producing an emulsion-polymerizable polymer.

[0002]

2. Description of the Related Art Conventionally, emulsion polymerization-based polymers have been polymerized by a polymerization process in which a polymer latex containing a polymer is produced by an emulsion polymerization method using a surfactant, and the polymer in the polymer latex is solidified with a coagulant to form a polymer slurry. Coagulation process to remove water, surfactant, extra coagulant, etc. from the polymer slurry while repeating washing and dehydration, and finally obtaining a dehydrated product with a low water content. It is manufactured through a drying process to make granules.

FIG. 1 shows a coagulation means for coagulating a polymer in a polymer latex in a coagulation process, and a cleaning / dewatering process of a polymer slurry in a subsequent cleaning / dehydration process.
It is a schematic block diagram which shows the washing | cleaning / dehydration means which performs dehydration. The coagulation means is composed of four coagulation tanks, that is, a first tank 11, a second tank 12, a third tank 13 and a fourth tank 14, each of which is provided with a stirrer 15, 16, 17, 18. ing. The washing / dehydrating means includes a vacuum filter 21 for washing and dehydrating the polymer slurry to obtain wet powder, and a reslurry tank 22 for adding water to the wet powder to obtain polymer slurry again.
And a centrifugal dehydrator 24 for dehydrating the polymer slurry supplied from the reslurry tank 22 by the liquid feed pump 23 to obtain a dehydrated product (dehydrated cake).

Here, the vacuum filter 21 has two parallel rolls 25 and 26, an endless filter cloth 27 which is hung on the rolls 25 and 26 and circulates between them.
Vacuum outlets 28, 29, 30 arranged immediately below the upper filter cloth 27 along the advancing direction of the filter cloth 27, and the vacuum outlet 2
Vacuum pumps 31, 32, 3 connected to 8, 29, 30
3, a cleaning water supply port 34 for supplying cleaning water onto the filter cloth 27 immediately after the evacuation from the evacuation port 28 to the evacuation port 29, and a evacuation from the evacuation port 29 to the evacuation port 3
The cleaning water supply port 35 for supplying the cleaning water is provided on the filter cloth 27 immediately after the transfer to 0, and the cleaning cloth supply port 35 is generally configured.

In the coagulation step, the polymer latex obtained by emulsion polymerization using a surfactant and sent from the polymerization step through the supply pipe 10 is supplied to the first tank 11 and stirred with stirring. A coagulant is added to the to coagulate the polymer in the polymer latex. This polymer latex is supplied to the second tank 12 and the amount of coagulant necessary for completely coagulating the polymer that has not coagulated by the first coagulation is additionally charged,
The second stage coagulation is performed to obtain a polymer slurry.
Further, in the third tank 13, a polymer for powder modification is added so as not to be blocked when dehydrated and dried. The polymer slurry thus obtained is supplied to the fourth tank 14 and heat-treated in the fourth tank 14.

In the washing / dehydrating step, the polymer slurry sent from the coagulating means by the liquid feed pump 19 is dehydrated by the vacuum filter 21 by vacuuming from the vacuum port 28, and then, While being washed with the washing water from the washing water supply port 34, it is dehydrated by evacuation from the vacuum suction port 29. Further, while being washed with the washing water from the cleaning water supply port 35, the vacuum suction from the vacuum suction port 30 is performed. It is dehydrated into wet powder, and this wet powder is stored in the reslurry tank 22.
At this time, water is added to form a polymer slurry again, and this polymer slurry is supplied to the centrifugal dehydrator 24 by the liquid feed pump 23 and then dehydrated to form a dehydrated product (dehydrated cake). It is sent to the drying process.

[0007]

In order to improve the productivity of the emulsion polymer, the coagulation of the polymer in the polymer latex in the coagulation process and the washing / dehydration of the polymer slurry in the washing / dehydration process as short as possible. Should be done in. However, since the polymer latex produced by the emulsion polymerization method contains a large amount of a surfactant, when the polymer latex or polymer slurry is stirred in each coagulation tank in the coagulation step, the polymer latex or polymer slurry is It foams. When the foaming of polymer latex or polymer slurry is severe, it is necessary to reduce the amount of polymer latex or polymer slurry in each coagulation tank by the amount of foaming, and as a result, it takes time to coagulate the polymer in the polymer latex in the coagulation process. There was a problem.

Further, by washing / dehydrating the polymer slurry, a vacuum filter 21 or a centrifugal dehydrator 2 as washing / dehydrating means.
Since the waste liquid discharged from No. 4 also contains a surfactant, when the foaming of the filtrate is severe, the transfer amount of the waste liquid flowing through the transfer pipe to the wastewater treatment process is reduced by the foaming amount. When the transfer amount of the waste liquid is limited, it is necessary to reduce the processing amount of the polymer slurry in the washing / dehydrating step, and as a result, there is a problem that it takes time to wash / dehydrate the polymer slurry in the washing / dehydrating step.

Therefore, the object of the present invention is to suppress the decrease in productivity due to the foaming of the surfactant used for emulsion polymerization,
An object of the present invention is to provide a method for producing an emulsion polymerization type polymer, which can efficiently obtain the emulsion polymerization type polymer.

[0010]

[Means for Solving the Problems] That is, the method for producing an emulsion-polymerized polymer according to the present invention comprises adding a coagulant to a polymer latex obtained by an emulsion-polymerization method using a surfactant, and adding the coagulant to the polymer latex. In the method for producing an emulsion polymerization-based polymer, which comprises coagulating a polymer to be prepared into a polymer slurry, dehydrating the polymer slurry, and further drying the polymer latex, the polymer latex 1 is added to the polymer latex.
It is characterized in that 0.01 to 2.0 parts by mass of an antifoaming agent is added to 00 parts by mass.

Further, the method for producing an emulsion polymerization type polymer of the present invention comprises adding a coagulant to the polymer latex obtained by the emulsion polymerization method using a surfactant to coagulate the polymer contained in the polymer latex. In the method for producing an emulsion polymerization-type polymer, which comprises dehydrating the polymer slurry and then drying the polymer slurry, the waste liquid generated by dehydrating the polymer slurry and sent to the wastewater treatment step has a content of 0 to 100 parts by mass of the waste liquid. It is characterized by adding 0.01 to 2.0 parts by mass of an antifoaming agent.

Further, in the method for producing an emulsion polymerization type polymer of the present invention, the surfactant is an alkyl sulfate ester salt,
Polyoxyethylene alkyl ether sulfate ester salt,
At least one or more surfactants selected from the group consisting of polyoxyethylene alkyl ether, alkylbenzene sulfonate, alkylsulfosuccinate, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester and alkyl phosphate ester salt. It is particularly suitable in some cases.

Further, in the method for producing an emulsion polymerization type polymer of the present invention, the coagulant is at least one metal salt selected from the group consisting of magnesium sulfate, barium sulfate, aluminum sulfate, calcium acetate and calcium chloride. It is particularly suitable in some cases. Further, in the method for producing an emulsion-polymerized polymer of the present invention, it is desirable that the defoaming agent is polydimethylsiloxane.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The method for producing an emulsion polymerization-based polymer of the present invention includes a polymerization step of producing a polymer latex containing a polymer by an emulsion polymerization method using a surfactant, and a polymer in the polymer latex is coagulated with a coagulant to obtain a polymer slurry. Washing / dehydrating step of removing water, surfactant, excess coagulant, etc. from the polymer slurry by repeating the steps, washing and dehydration, and finally obtaining a dehydrated product with a low water content, and drying the dehydrated product to form powder particles A manufacturing method having a drying step for forming a body is characterized by using a specific amount of an antifoaming agent in the coagulation step and / or the washing / dehydrating step.

The polymerization means for producing a polymer latex in the polymerization step of the method for producing an emulsion polymerization type polymer of the present invention is not particularly limited as long as it produces a polymer latex containing a polymer by an emulsion polymerization method. As such a polymerization means, a conventionally known polymerization apparatus can be used, and examples thereof include a polymerization tank equipped with a stirrer. Further, in the case of producing a graft copolymer in which a hard polymer-forming monomer is graft-polymerized with a rubber-like polymer, for example, a polymerization apparatus equipped with a rubber polymerization tank and one or more graft polymerization tanks is used. Can be used.

As the surfactant used in the emulsion polymerization method, the surfactant conventionally used in the emulsion polymerization method can be used. The surfactant used in the method for producing the emulsion-polymerized polymer of the present invention,
From the viewpoint of latex stability during emulsion polymerization and liquid transfer, alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, polyoxyethylene alkyl ether, alkylbenzene sulfonate, alkyl sulfosuccinate, polyoxyethylene fatty acid ester At least one surfactant selected from the group consisting of a sorbitan fatty acid ester, a glycerin fatty acid ester and an alkyl phosphate ester salt is suitable.

The coagulation means for coagulating the polymer in the polymer latex in the coagulation step of the method for producing the emulsion-polymerized polymer of the present invention may be any means that coagulates the polymer in the polymer latex into a polymer slurry. It is not limited to the illustrated example. As such coagulation means, conventionally known means can be used.

In the coagulation step, the antifoaming agent may be added to the polymer latex so long as the antifoaming agent is added to the polymer latex stirred in the coagulation tank in the coagulation means, and there is no particular limitation. Not done. For example, in all the coagulation tanks shown in FIG. 1, in order for the polymer latex and the polymer slurry to contain an antifoaming agent, the antifoaming agent is added to the polymer latex in the first tank 11 or the first tank 11. The polymer latex before being supplied to the first tank 11 is preferable because it is preferably added to the polymer latex before being supplied, and the foaming of the polymer latex when discharged from the supply pipe 10 to the first tank 11 is suppressed. Is more preferably added to.

The amount of the defoaming agent added to the polymer latex is 0.0 based on 100 parts by mass of the polymer latex.
The range is 1 to 2.0 parts by mass. When the amount of the defoaming agent is less than 0.01 parts by mass with respect to 100 parts by mass of the polymer latex, the effect of suppressing foaming of the polymer latex, the polymer slurry, and the waste liquid generated by dehydration of the polymer slurry becomes insufficient. On the other hand, if the amount of the defoaming agent exceeds 2.0 parts by mass with respect to 100 parts by mass of the polymer latex, the amount of the defoaming agent added will be uneconomical.

The defoaming agent added to the polymer latex is not particularly limited as long as it suppresses the foaming of the polymer latex by the surfactant used in the emulsion polymerization method. Among such defoaming agents, polydimethylsiloxane is preferably used because it is excellent in foam breaking property even when added in a small amount.

In the coagulation step, as the coagulant for coagulating the polymer in the polymer latex, a coagulant conventionally used in the production of emulsion polymerization type polymers can be used. As the coagulant used in the method for producing the emulsion-polymerized polymer of the present invention, at least one metal salt selected from the group consisting of magnesium sulfate, barium sulfate, aluminum sulfate, calcium acetate and calcium chloride can be easily prepared. It is suitable because it is available and economical from an industrial point of view.

The washing / dehydrating means for washing and dehydrating the polymer slurry in the washing / dehydrating step of the method for producing an emulsion-polymerized polymer of the present invention is capable of washing and dehydrating the polymer slurry to obtain a dehydrated product. It suffices that it be provided, and the illustrated example is not limited. As such washing / dehydrating means, conventionally known vacuum filters, centrifugal dehydrators,
A pressure dehydrator or the like can be used. Also, a plurality of these may be used in combination.

The timing of adding the defoaming agent to the waste liquid that is generated by washing and dehydrating the polymer slurry and is sent to the wastewater treatment step is such that the amount of the defoaming agent is 0.01 to 2. A defoaming agent may be added to the latex so that the amount of the defoaming agent becomes 0 parts by mass, but the defoaming agent may be contained in the waste liquid flowing through the transfer pipe to the wastewater treatment process, for example, the vacuum shown in FIG. It is preferably added immediately after being discharged from the filter 21 and the centrifugal dehydrator 24 or in the middle of the transfer pipe to the wastewater treatment process.

The amount of the defoaming agent added to the waste liquid is 10
The range is 0.01 to 2.0 parts by mass with respect to 0 parts by mass. When the amount of the defoaming agent is less than 0.01 parts by mass with respect to 100 parts by mass of the waste liquid, the effect of suppressing foaming of the waste liquid becomes insufficient. On the other hand, even if the defoaming agent is added in an amount of more than 2.0 parts by mass with respect to 100 parts by mass of the waste liquid, improvement in the effect of suppressing foaming of the waste liquid cannot be expected so much, and the increase in the amount of the defoaming agent causes Become an economy. In the coagulation process, if a defoaming agent is added to the polymer latex, the waste solution contains the defoaming agent, so if there is no foaming of the waste solution, it is not necessary to add the defoaming agent, but foaming If observed, an antifoaming agent may be added. In this case, the amount of the defoaming agent added to the waste liquid is 0.01 to 1.0 with respect to 100 parts by mass of the waste liquid.
The range is parts by mass.

The defoaming agent added to the waste liquid is not particularly limited as long as it suppresses the foaming of the waste liquid by the surfactant used in the emulsion polymerization method. Among such defoaming agents, polydimethylsiloxane is preferably used because it is excellent in foam breaking property even when added in a small amount.

The drying means for drying the dehydrated product in the drying step of the method for producing the emulsion-polymerized polymer of the present invention may be any one that can dry the washed / dehydrated dehydrated product into powder and granules, and is not particularly limited. It is not done. As such a drying means, a conventionally known drier can be used, and examples thereof include an airflow drier, a fluidized drier, a hot air drier and a compression dehydrator extruder. Moreover, you may use combining these dryers in multiple numbers.

Examples of the emulsion-polymerizable polymer produced by the method for producing an emulsion-polymerizable polymer of the present invention include, for example, methyl methacrylate-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene graft copolymer. , Methyl methacrylate- (meth) acrylic acid ester-based graft copolymer, acrylonitrile-butadiene-styrene-based copolymer, acrylonitrile-butadiene-styrene-based graft copolymer, silicone / acrylic composite rubber-based graft copolymer, styrene -Butadiene-based copolymer rubber, (meth) acrylic acid ester-based copolymer, (meth) acrylic acid ester-styrene copolymer,
(Meth) acrylic acid ester-styrene-α-methylstyrene copolymer, acrylonitrile-styrene copolymer, acrylonitrile-styrene- (meth) acrylic acid ester copolymer, acrylonitrile-styrene-α
-Methylstyrene copolymer, polytetrafluoroethylene-containing (meth) acrylic acid ester-based graft copolymer, and the like.

In the method for producing the emulsion-polymerized polymer of the present invention described above, the polymer latex is added in an amount of 0.01 to 2.0 with respect to 100 parts by mass of the polymer latex.
Since the anti-foaming agent is added in a mass part, it is possible to suppress the foaming of the polymer latex and the polymer slurry that are stirred in the coagulation tank in the coagulation process, and it is necessary to reduce the amount of the polymer latex processed in the coagulation process. Absent. In addition, it is possible to suppress foaming of the waste liquid that is generated by dehydrating the polymer slurry and that is sent to the wastewater treatment process, and there is no need to reduce the amount of waste liquid that is sent to the wastewater treatment process. Does not have to be reduced. This allows
It is possible to efficiently reduce the productivity of the emulsion polymerization type polymer and obtain the emulsion polymerization type polymer.

In addition, in the method for producing the emulsion polymerization type polymer of the present invention, the waste liquid 10 is generated by dehydrating the polymer slurry and sent to the waste water treatment step.
Since 0.01 to 2.0 parts by mass of antifoaming agent is added to 0 parts by mass, it is necessary to suppress foaming of the waste liquid sent to the wastewater treatment process and reduce the amount of the waste liquid sent to the wastewater treatment process. Disappears. As a result, the amount of polymer slurry to be treated in the washing / dehydration step does not have to be reduced, the productivity of the emulsion-polymerized polymer can be prevented from decreasing, and the emulsion-polymerized polymer can be efficiently obtained.

[0030]

The present invention will be further described with reference to the following examples, but the present invention is not limited to these examples. Further, in the present examples, “parts” and “%” mean “parts by mass” and “mass%” unless otherwise specified.

[Example 1] 2 parts of tetraethoxysilane,
0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and 97.5 parts of octamethylcyclotetrasiloxane were mixed to obtain 100 parts of a siloxane mixture. After adding 100 parts of the siloxane mixture to 200 parts of distilled water in which 1 part of sodium dodecylbenzenesulfonate and 1 part of dodecylbenzenesulfonic acid were dissolved respectively, and preliminarily stirring with a homomixer at 10,000 rpm,
An homogenizer was used to emulsify and disperse under a pressure of 300 kg / cm ² to obtain an organosiloxane latex.
This latex was transferred to a separable flask equipped with a condenser and a stirring blade, and mixed with stirring at 5 ° C. for 5 hours.
After heating for 20 hours, the mixture was left standing at 20 ° C., and after 48 hours, the pH of this latex was neutralized to 7.4 with an aqueous sodium hydroxide solution to complete the polymerization to obtain a polyorganosiloxane latex. The polymerization rate of the obtained polyorganosiloxane was 89.5%, and the average particle size of the polyorganosiloxane was 0.16 μm.

33 parts of polyorganosiloxane latex was placed in a 50 L stainless steel polymerization apparatus equipped with a jacket heater and a stirrer, and polyoxyethylene alkylphenyl ether sulfate (manufactured by Kao Corporation,
1.4 parts of Emal NC-35) and 271 parts of distilled water were added, the inside of the polymerization apparatus was replaced with nitrogen, and the temperature was raised to 50 ° C.
A mixed solution of 78.4 parts of n-butyl acrylate, 1.6 parts of allyl methacrylate and 0.40 part of tert-butyl hydroperoxide was charged and stirred in the polymerization apparatus for 30 minutes to infiltrate the polyorganosiloxane particles with the mixed solution. Let Then, a mixed solution of 0.002 parts of ferrous sulfate, 0.006 parts of ethylenediaminetetraacetic acid disodium salt, 0.26 parts of Rongalit and 5 parts of distilled water was charged to initiate radical polymerization, and then the internal temperature was raised to 70 ° C. Polymerization was completed by holding for 2 hours to obtain a composite rubber latex. A part of this latex was sampled, and the average particle size of the composite rubber was measured and found to be 0.22 μm.

A mixed solution of 0.05 part of tert-butyl hydroperoxide and 10 parts of methyl methacrylate was added dropwise to this composite rubber latex at 70 ° C. for 15 minutes, and then 70 ° C. was maintained for 4 hours to give a composite rubber. The graft polymerization of was completed to obtain a graft polymer latex. The polymerization rate of methyl methacrylate was 96.4%. The average particle size of the obtained graft copolymer was measured and found to be 0.24 μm.

The total amount of the obtained graft copolymer latex was 0.10 with respect to 100 parts of the graft copolymer latex.
5 parts of polydimethylsiloxane was added, and this was added dropwise to 400 parts of hot water with a 5.0% sulfuric acid band in a coagulation tank equipped with a stirrer while maintaining the coagulation tank at 90 ° C. The rotation speed of the stirrer at this time was 100 rpm. Immediately after the completion of the dropping of the graft copolymer latex, the inside of the coagulation tank was observed to confirm the presence or absence of foaming. The results are shown in Table 1. Here, ◯ in the table represents a state in which there is no bubbling and the liquid surface is visible, and x represents a state in which there is bubbling and the liquid surface is invisible.
Further, the graft copolymer slurry obtained by coagulating the graft copolymer in the graft copolymer latex,
Filtration was performed using a sieve having a mesh size of 250 mesh, and the time from immediately after the completion of filtration until the disappearance of bubbles in the filtrate was measured. The results are shown in Table 1.

Example 2 0.1 part of 2,2-azobis (2,4-dimethylvaleronitrile) was dissolved in a mixed solution of 50 parts of dodecyl methacrylate and 50 parts of methyl methacrylate. To this, a mixed solution of 2.0 parts of sodium dodecylbenzenesulfonate and 300 parts of distilled water was added, and the mixture was stirred with a homomixer at 10,000 rpm for 2 minutes,
The homogenizer was passed twice at a pressure of 30 MPa to obtain a stable preliminary dispersion liquid. This pre-dispersion liquid was placed in a separable flask equipped with a stirring blade, a condenser, a thermocouple, and a nitrogen inlet, the internal temperature was raised to 80 ° C. under a nitrogen stream, and the mixture was radically polymerized by stirring for 3 hours to disperse polymer particles. A liquid was obtained.
The solid content concentration of this polymer particle dispersion is 25.1%,
The particle size distribution shows a single peak and the weight average particle size is 1
It was 90 nm. As a polytetrafluoroethylene-based particle dispersion liquid, Fluon AD936 manufactured by Asahi Glass was used. A
D936 has a solid content concentration of 63.0% and contains 5% of polyoxyethylene alkylphenyl ether with respect to polytetrafluoroethylene. AD936
The particle size distribution of showed a single peak, and the weight average particle size was 290 nm. 116.7 parts of distilled water was added to 83.3 parts of AD936 to obtain a polytetrafluoroethylene-based particle dispersion having a solid content of 26.2%. This polytetrafluoroethylene-based particle dispersion liquid contains 25% polytetrafluoroethylene-based particles and 1.2% polyoxyethylene alkylphenyl ether. 120
Parts of polytetrafluoroethylene-based particle dispersion (30 parts of polytetrafluoroethylene) and 199.2 parts of polymer particle dispersion (50 parts of dodecyl methacrylate / methyl methacrylate copolymer), stirring blade, condenser, thermoelectric Paired with a separable flask equipped with a nitrogen inlet,
The mixture was stirred under a nitrogen stream for 1 hour. After that, the temperature of the system was raised to 80 ° C., the mixture was stirred for 1 hour, and then iron (II) sulfate 0.001 was added.
Part, disodium ethylenediaminetetraacetate 0.003
Part, 0.24 parts of Rongalite salt, and 60.8 parts of distilled water were added, and a mixed solution of 20 parts of methyl methacrylate and 0.4 parts of tert-butyl hydroperoxide was added dropwise over 1 hour. The internal temperature was maintained at 80 ° C. for 1 hour to complete the radical polymerization. Separation of solid matter was not observed through a series of operations, and a uniform dispersion liquid was obtained.

The total amount of the obtained polymer latex was transferred to a coagulation tank equipped with a stirrer, and the polymer latex 100 was added thereto.
1.0 part of polydimethylsiloxane was added to each part while maintaining the inside of the coagulation tank at 95 ° C., and further 7.0 parts of calcium acetate as a coagulant was added. The rotation speed of the stirrer at this time was 100 rpm. Immediately after the addition of the coagulant was completed, the inside of the coagulation tank was observed to confirm the presence or absence of foaming. The results are shown in Table 1. Moreover, the polymer slurry obtained by coagulating the polymer in the polymer latex is opened with a mesh 25
Filtration was carried out using a 0 mesh sieve, and the time from immediately after the completion of filtration until the disappearance of bubbles in the filtrate was measured. The results are shown in Table 1.

Comparative Example 1 Coagulation of the graft copolymer was carried out in the same manner as in Example 1 except that the graft copolymer latex obtained in the same manner as in Example 1 was used and no defoaming agent was added to it. I went. Immediately after the completion of the dropping of the graft copolymer latex, the inside of the coagulation tank was observed to confirm the presence or absence of foaming. The results are shown in Table 1. Further, the graft copolymer slurry obtained by coagulating the graft copolymer in the graft copolymer latex is filtered using a sieve having a mesh size of 250 mesh, and immediately after the completion of the filtration until the bubbles of the filtrate disappear. The time was measured. The results are shown in Table 1.

Comparative Example 2 Polymer coagulation was carried out in the same manner as in Example 2 except that the polymer latex obtained in the same manner as in Example 2 was used and no defoaming agent was added thereto. Observe the inside of the coagulation tank immediately after the addition of the coagulant is finished,
The presence or absence of foaming was confirmed. The results are shown in Table 1. In addition, the polymer slurry obtained by coagulating the polymer in the polymer latex was filtered using a sieve having a mesh size of 250 mesh, and the time immediately after the completion of filtration until the disappearance of bubbles in the filtrate was measured. The results are shown in Table 1.

[0039]

[Table 1]

[Example 3] To the total amount of the graft copolymer latex obtained in the same manner as in Example 1, 0.5 part of polydimethylsiloxane was added to 100 parts of the graft copolymer latex. Then, it was added dropwise to 400 parts of hot water containing 1.5% of calcium chloride in a coagulation tank equipped with a stirrer while maintaining the coagulation tank at 95 ° C. The rotation speed of the stirrer at this time was 100 rpm. Immediately after the completion of the dropping of the graft copolymer latex, the latex being coagulated in the coagulation tank was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate. Put 400 ml of this filtrate into a 1000 ml graduated cylinder and pass 1 L through a glass diffuser stone.
Air was blown into the filtrate for 3 minutes by an air bubbling method in which air was blown at a flow rate of / min. The amount of foaming immediately after stopping the blowing of air (foam amount + liquid amount) and the amount of foaming after stopping the blowing of air for 3 minutes (foam amount + liquid amount) were measured. The results are shown in Table 2.

[Example 4] The whole amount of the polymer latex obtained in the same manner as in Example 2 was transferred to a coagulation tank equipped with a stirrer, and 1.0 part was added to 100 parts of the polymer latex.
Part of polydimethylsiloxane was added while keeping the inside of the coagulation tank at 95 ° C., and further 7.0 parts of calcium acetate was added as a coagulant. The rotation speed of the stirrer at this time is 100 r
pm. Immediately after the addition of the coagulant was completed, the latex being coagulated in the coagulation tank was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate. 400 ml of this filtrate is added to 100
The mixture was placed in a 0 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. The amount of foaming immediately after stopping the blowing of air (foam amount + liquid amount) and the amount of foaming after stopping the blowing of air for 3 minutes (foam amount + liquid amount) were measured. The results are shown in Table 2.

[Comparative Example 3] Coagulation of the graft copolymer was carried out in the same manner as in Example 3 except that the graft copolymer latex obtained in the same manner as in Example 1 was used and no defoaming agent was added thereto. I went. Immediately after the dropping of the graft copolymer latex was completed, the latex being coagulated in the coagulation tank was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate.
400 ml of this filtrate was placed in a 1000 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. The amount of foaming immediately after stopping the blowing of air (foam amount + liquid amount) and the amount of foaming after stopping the blowing of air for 3 minutes (foam amount + liquid amount) were measured. The results are shown in Table 2.

Comparative Example 4 Polymer coagulation was carried out in the same manner as in Example 4 except that the polymer latex obtained in the same manner as in Example 2 was used and no defoaming agent was added thereto. Immediately after the addition of the coagulant was completed, the latex being coagulated in the coagulation tank was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate. 400 ml of this filtrate was placed in a 1000 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. Immediately after stopping the blowing of air, the amount of foaming (foaming amount + liquid amount), and by stopping the blowing of air, 3
The foaming amount (foaming amount + liquid amount) after standing for 1 minute was measured. The results are shown in Table 2.

[0044]

[Table 2]

[Example 5] 100 parts by mass of the graft copolymer latex obtained in the same manner as in Example 1 was mixed with 400 parts of hot water containing calcium chloride of 1.5% in a coagulation tank equipped with a stirrer.
While maintaining the inside of the coagulation tank at 95 ° C., the solution was dropped. The rotation speed of the stirrer at this time was 100 rpm. The graft copolymer slurry obtained by solidifying the graft copolymer in the graft copolymer latex was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate. To 100 parts by mass of this filtrate, 400 parts by mass of polydimethylsiloxane was added and 400 ml of the stirred solution was put into a 1000 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. The amount of foaming immediately after stopping the blowing of air (foam amount + liquid amount) and the amount of foaming after stopping the blowing of air for 3 minutes (foam amount + liquid amount) were measured. The results are shown in Table 3.
Shown in.

[Example 6] 100 parts by mass of the polymer latex obtained in the same manner as in Example 2 was transferred to a coagulation tank equipped with a stirrer, and calcium acetate was used as a coagulant while keeping the inside of the coagulation tank at 95 ° C. 0 part was added. The rotation speed of the stirrer at this time was 100 rpm. The polymer slurry obtained by coagulating the polymer in the polymer latex was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate. 400 m of a solution obtained by adding 1.5 parts by mass of polydimethylsiloxane to 100 parts by mass of this filtrate and stirring.
1 was put in a 1000 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. Amount of foam immediately after stopping blowing air (foam amount + liquid amount), and amount of foam after stopping blowing air for 3 minutes (foam amount + liquid amount)
Was measured. The results are shown in Table 3.

[Comparative Example 5] Using the graft copolymer latex obtained in the same manner as in Example 1, the graft copolymer was coagulated in the same manner as in Example 5. The graft copolymer slurry obtained by solidifying the graft copolymer in the graft copolymer latex was filtered using a sieve having a mesh size of 250 mesh to obtain a filtrate. 400m of this filtrate
1 was put in a 1000 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. Amount of foam immediately after stopping blowing air (foam amount + liquid amount), and amount of foam after stopping blowing air for 3 minutes (foam amount + liquid amount)
Was measured. The results are shown in Table 3.

[Comparative Example 6] Using the polymer latex obtained in the same manner as in Example 2, the polymer was coagulated in the same manner as in Example 6. The polymer slurry obtained by coagulating the polymer in the polymer latex is opened 2
Filtration was performed using a 50-mesh sieve to obtain a filtrate. 400 ml of this filtrate was placed in a 1000 ml graduated cylinder, and air was blown into the filtrate for 3 minutes in the same manner as in Example 3. The amount of foaming immediately after stopping the blowing of air (foam amount + liquid amount) and the amount of foaming after stopping the blowing of air for 3 minutes (foam amount + liquid amount) were measured. The results are shown in Table 3.

[0049]

[Table 3]

[0050]

As described above, the method for producing an emulsion-polymerized polymer of the present invention comprises adding a coagulant to a polymer latex obtained by an emulsion-polymerization method using a surfactant, and adding the coagulant to the polymer latex. In the method for producing an emulsion polymerization type polymer, which comprises coagulating a polymer to be a polymer slurry, dehydrating the polymer slurry, and further drying the polymer slurry, the polymer latex is added in an amount of 0.01 to 2.0 parts by mass based on 100 parts by mass of the polymer latex. Since this is a method of adding a defoaming agent in some parts, it is possible to efficiently suppress the decrease in productivity due to foaming of the surfactant used for emulsion polymerization, and to efficiently obtain an emulsion polymerization type polymer.

Further, the method for producing the emulsion polymerization type polymer of the present invention comprises adding a coagulant to the polymer latex obtained by the emulsion polymerization method using a surfactant to coagulate the polymer contained in the polymer latex. In the method for producing an emulsion polymerization-type polymer, which comprises dehydrating the polymer slurry and then drying the polymer slurry, the waste liquid generated by dehydrating the polymer slurry and sent to the wastewater treatment step has a content of 0 to 100 parts by mass of the waste liquid. Since this is a method in which 0.01 to 2.0 parts by mass of the defoaming agent is added, it is possible to efficiently suppress the decrease in productivity due to foaming of the surfactant used for emulsion polymerization and to efficiently obtain the emulsion polymerization type polymer. .

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a coagulation unit and a cleaning / dehydration unit in an apparatus for producing an emulsion polymerization type polymer.

Claims (5)

[Claims] 1. A coagulant is added to a polymer latex obtained by an emulsion polymerization method using a surfactant to coagulate a polymer contained in the polymer latex to form a polymer slurry, which is then dehydrated. In the method for producing an emulsion-polymerized polymer to be dried, the polymer latex is added to the polymer latex 100.
A method for producing an emulsion-polymerized polymer, which comprises adding 0.01 to 2.0 parts by mass of an antifoaming agent to parts by mass. 2. A coagulant is added to a polymer latex obtained by an emulsion polymerization method using a surfactant to coagulate a polymer contained in the polymer latex to form a polymer slurry, which is then dehydrated. In a method for producing an emulsion polymerization-type polymer to be dried, 0.01 to 2.0 parts by mass of a defoaming agent is added to 100 parts by mass of the waste liquid in a waste liquid generated by dehydrating a polymer slurry and sent to a wastewater treatment process. A method for producing an emulsion-polymerized polymer, which comprises adding 3. The surfactant is an alkyl sulfate ester salt, polyoxyethylene alkyl ether sulfate ester salt, polyoxyethylene alkyl ether, alkylbenzene sulfonate, alkylsulfosuccinate, polyoxyethylene fatty acid ester, sorbitan fatty acid ester. 3. The method for producing an emulsion-polymerized polymer according to claim 1, which is at least one kind of surfactant selected from the group consisting of a glycerin fatty acid ester and an alkyl phosphate ester salt. 4. The coagulant is at least one metal salt selected from the group consisting of magnesium sulfate, barium sulfate, aluminum sulfate, calcium acetate and calcium chloride. The method for producing an emulsion-polymerized polymer according to any one of 1 to 10. 5. The method for producing an emulsion-polymerized polymer according to claim 1, wherein the defoaming agent is polydimethylsiloxane.