JP2003261615A - Method and apparatus for producing emulsion polymerization-based polymer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for producing an emulsion polymerization-based polymer which can obtain a polymer having reduced deformation of polymer particles caused by dehydration and a high bulk density after drying. <P>SOLUTION: In the method for producing the emulsion polymerization-based polymer comprising dehydrating a polymer slurry obtained by agglomerating a polymer present in the polymer latex obtained by emulsion polymerization, and then drying the polymer, the polymer slurry or a water-containing polymer obtained therefrom is dehydrated by a belt pressing dehydrator 40. The apparatus for producing the emulsion polymerization-based polymer has a belt pressing hydrator 40 for dehydrating a polymer slurry or a water-containing polymer obtained therefrom. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing an emulsion-polymerized polymer, and more specifically, dehydration,
The present invention relates to a method and an apparatus for producing an emulsion-polymerized polymer that can obtain a polymer having a high bulk density after drying.

[0002]

2. Description of the Related Art Conventionally, emulsion polymerization type polymers have a polymerization step of producing a polymer latex containing a polymer by an emulsion polymerization method, a coagulation step of aggregating a polymer in the polymer latex into a polymer slurry, and repeating washing and dehydration. However, it is manufactured through a washing / dehydration step of finally removing water, a flocculant, etc. from the polymer slurry to obtain a dehydrated product having a low water content, and a drying process of drying the dehydrated product to form a granular material.

FIG. 3 is a schematic structural view showing a washing / dehydrating means for carrying out the washing / dehydrating step in a conventional emulsion polymerization type polymer production apparatus. The washing / dehydrating means includes a vacuum filter 11 for washing and dehydrating the polymer slurry sent from the coagulation step to obtain wet powder, a reslurry tank 12 for adding water to the wet powder to obtain the polymer slurry again, and a reslurry. A centrifugal dehydrator 14 for dehydrating the polymer slurry supplied from the tank 12 by the liquid feed pump 13 to obtain a dehydrated product (dehydrated cake) is roughly configured.

Here, the vacuum filter 11 has two parallel rolls 15 and 16 and an endless filter cloth 17 which is hung on the rolls 15 and 16 and circulates between them.
Vacuum outlets 18, 19 and 20 arranged immediately below the upper filter cloth 17 along the traveling direction of the filter cloth 17, and the vacuum outlet 1
Vacuum pumps 21,22,2 connected to 8,19,20
3, a cleaning water supply port 24 for supplying cleaning water onto the filter cloth 17 immediately after the evacuation from the evacuation port 18 to the evacuation port 19, and a evacuation from the evacuation port 19 to the evacuation port 2
The cleaning water supply port 25 for supplying the cleaning water is provided on the filter cloth 17 immediately after the transfer to 0, and is roughly configured.

In this washing / dehydrating means, the polymer slurry sent from the solidification step is vacuum filtered by the vacuum filter 11
At this time, it is dehydrated by vacuum evacuation from the vacuum port 18, and then it is dehydrated by vacuum evacuation from the vacuum port 19 while being washed with cleaning water from the cleaning water supply port 24.
While being washed with the wash water from the wash water supply port 25, it is dehydrated by vacuuming from the vacuum port 20 to become wet powder, and this wet powder is added with water in the reslurry tank 12 to become a polymer slurry again, This polymer slurry is supplied to the centrifugal dehydrator 14 by the liquid feed pump 13 and then dehydrated to be a dehydrated product (dehydrated cake).
It is sent to the next drying step.

[0006]

However, when the polymer slurry is dehydrated by the centrifugal dehydrator 14, the centrifugal force applied to the polymer slurry is too large, so that the dehydration efficiency is good, but the polymer particles are deformed. . When the polymer particles are deformed, voids increase between the polymer particles obtained after the drying step, which reduces the bulk density of the emulsion polymerization type polymer (that is, the emulsion polymerization type polymer is bulky), and When it was shipped as a product, the amount of polymer packed in the bag had to be limited or the bag had to be made larger.

[0007] Therefore, an object of the present invention is to provide a method and an apparatus for producing an emulsion polymerization type polymer, in which deformation of polymer particles due to dehydration treatment is small and a polymer having a high bulk density can be obtained after drying.

[0008]

[Means for Solving the Problems] That is, the method for producing an emulsion-polymerized polymer of the present invention comprises dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by the emulsion-polymerization method, and then drying it. In the method for producing an emulsion polymerization type polymer, the polymer slurry is dehydrated by a belt press dehydrator.

Further, the method for producing an emulsion polymerization type polymer of the present invention is a method for producing an emulsion polymerization type polymer in which a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by the emulsion polymerization method is dehydrated and then dried. In the production method, the hydrous polymer obtained by preliminarily dehydrating the polymer slurry is dehydrated by a belt press dehydrator. Here, the water content of the water-containing polymer is preferably 30 to 80% by mass.

Further, in the method for producing an emulsion polymerization type polymer of the present invention, the belt press dehydrator is used as a belt press dehydrator between the endless upper filter cloth and the lower filter cloth, which are opposed to each other, and which have a polymer slurry or a water-containing polymer. It is desirable to use a horizontal belt press dewatering machine which sandwiches and depressurizes under pressure.

Further, the apparatus for producing an emulsion polymerization type polymer of the present invention is a belt press dehydration for dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by an emulsion polymerization method or a water-containing polymer obtained therefrom. It is characterized by having a machine.

The belt press dewatering machine is a horizontal belt press dewatering machine for sandwiching a polymer slurry or a water-containing polymer between endless upper filter cloths and lower filter cloths which are arranged to face each other and performing pressure dewatering. Is desirable. Further, it is desirable that a preliminary dewatering machine is provided before the belt press dewatering machine.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. The apparatus for producing an emulsion polymerization-based polymer of the present invention is a polymerization means for producing a polymer latex containing a polymer by an emulsion polymerization method, a coagulation means for aggregating a polymer in a polymer latex into a polymer slurry, and a polymer while repeating washing and dehydration. In the manufacturing apparatus provided with a washing / dehydrating means for removing water, a flocculant, etc. from the slurry to finally obtain a dehydrated product having a low water content, and a drying means for drying the dehydrated product to form a granular material, It is characterized by a dehydrating means.

FIG. 1 is a schematic block diagram showing an example of washing / dehydrating means in the apparatus for producing an emulsion-polymerized polymer of the present invention. The washing / dehydrating means includes a vacuum filter 11 for washing and dehydrating the polymer slurry sent from the coagulation step to obtain wet powder, a reslurry tank 12 for adding water to the wet powder to obtain the polymer slurry again, and a reslurry. A preliminary dehydrator 30 for preliminarily dehydrating the polymer slurry supplied from the tank 12 by the liquid feed pump 13 to obtain a water-containing polymer, and a belt press dehydrator 40 for further dehydrating the water-containing polymer to obtain a dehydrated product (dehydrated cake). It is provided with a schematic configuration.

The pre-dehydrator 30 comprises two parallel rolls 3.
1, 32 and a roll 31 and an endless filter cloth 33 that is hung on the roll 32 and circulates between them, and is roughly configured. The polymer slurry supplied on the filter cloth 33 is It is dehydrated by sucking a vacuum from the bottom against water.

The belt press dewatering machine 40 is a conventionally known belt press used for dewatering sludge generated in sewage treatment as described in JP-A-56-89810, for example. A dehydrator can be used. FIG. 2 is a front view of a main part of an example of a horizontal belt press dehydrator used as the belt press dehydrator 40. The belt press dehydrator 40 includes a drive roll (not shown) and a plurality of tension rolls (not shown). (Abbreviated) and an endless lower filter cloth 41 which circulates around these rolls
, A drive belt (not shown), a plurality of tension rolls 42, 43 ... And an endless upper filter cloth 44 circulated around these rolls.
The upper belt conveyor including the water-containing polymer 51
Is sandwiched between filter cloths and arranged at a predetermined interval for pressure dehydration.

Below the lower filter cloth 41 where the lower filter cloth 41 and the upper filter cloth 44 face each other, a plurality of lower roll support bases 46, 46, ...
, And lower rolls 47, 47, ..., Which are rotatably attached to the lower roll support base 46, the lower filter cloth 41 is horizontally supported by the lower rolls 47, 47 ,. . The upper frame 4 is provided above the upper filter cloth 44 where the lower filter cloth 41 and the upper filter cloth 44 face each other.
A plurality of upper roll supports 49, 49 ...
, And upper rolls 50, 50 ..., Which are rotatably attached to the upper roll support base 49, respectively, are directly above the lower rolls 47, 47, ... And the lower filter cloth 41 and the upper filter cloth 44. The lower roll 48 and the upper roll 51 are provided such that the distance between the lower roll 48 and the upper roll 51 becomes narrower in the traveling direction.

As the lower filter cloth 41 and the upper filter cloth 44 of the belt press dehydrator 40, for example, filter cloths used in conventional belt press dehydrators such as nylon, polyester and cotton cloth can be used. Further, in order to prevent clogging of the lower filter cloth 41 and the upper filter cloth 44, the belt press dehydrator 40 is preferably equipped with a high-pressure cleaning device for cleaning the filter cloth. Further, as the belt press dehydrator, as described in JP-A-56-89810, an upstream side of a pressure dehydration section in which a lower filter cloth 41 and an upper filter cloth 44 are arranged so as to face each other. A gravity dehydration section for dehydrating water from the water-containing polymer by gravity falling by gravity only with the lower filter cloth 41. The lower filter cloth 41 is provided downstream of the pressure dehydration section.
In the state in which the dehydrated water-containing polymer is sandwiched between the upper filter cloth 44 and the upper filter cloth 44, a shear compression unit that performs a shear compression dehydration by meandering between the plurality of tension rolls 43, ... You may use what was provided.

The polymerization means in the apparatus 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.

The coagulation means in the emulsion polymerization type polymer production apparatus of the present invention may be any means as long as it aggregates the polymer in the polymer latex into a polymer slurry,
There is no particular limitation. As such coagulation means, conventionally known means can be used, and examples thereof include a coagulation tank equipped with a stirrer. Also, the coagulation means is
It may have a plurality of coagulation tanks.

The drying means in the apparatus for producing the emulsion-polymerized polymer of the present invention is not particularly limited as long as it is capable of drying the washed and dehydrated dehydrated product to form a granular material. 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.

Next, the method for producing the emulsion-polymerizable polymer of the present invention will be described by taking a graft copolymer as an emulsion-polymerizable polymer as an example. First, the rubber-like polymer obtained in the rubber polymerization tank is transferred to a graft polymerization tank, a hard polymer-forming monomer is mixed with the rubber-like polymer, and a graft copolymer latex is obtained by a known emulsion polymerization method.

Then, the graft copolymer latex is supplied from the graft polymerization tank to the first tank of the aggregating step, and an aggregating agent is added to this to agglomerate the graft copolymer in the graft copolymer latex. By supplying this aggregated graft copolymer latex to the second tank and additionally adding the aggregating agent in an amount necessary for completely aggregating the graft copolymer that was not aggregated by the first-stage aggregation, 2 Aggregation of the second step is performed to complete the aggregation to obtain a graft copolymer slurry.

Further, the graft copolymer slurry is obtained by heating and solidifying in the third tank and the fourth tank.

The graft copolymer slurry sent from the coagulation step is dehydrated by the vacuum filter 11 by vacuuming from the vacuum port 18, and then washed with the wash water from the wash water supply port 24. Meanwhile, dehydration is performed by vacuuming from the vacuum inlet 19, and further, while washing with cleaning water from the cleaning water supply port 25, dehydration is performed by vacuuming from the vacuum inlet 20 to obtain wet powder. Water is added to the wet powder in the reslurry tank 12 to form a polymer slurry again, and the polymer slurry is supplied to the preliminary dehydrator 30 by the liquid feed pump 13 and dehydrated by vacuum dehydration to obtain a water-containing polymer. Subsequently, this water-containing polymer is supplied to a belt press dehydrator 40, and is sandwiched between endless upper filter cloths 44 and lower filter cloths 41 arranged facing each other so that the intervals become narrower, and pressure dehydration is performed. , Dehydrated product (dehydrated cake) is obtained.

The dehydrated product from the belt press dehydrator 40 is
If necessary, the mixture is pulverized by a mill, a crusher, etc., dried by a gas stream dryer, and then further dried by a fluidized dryer to obtain a powdery or granular graft copolymer.

As the rubber-like polymer obtained in the rubber polymerization tank, 1,3-butadiene, isoprene, chloroprene,
And a homopolymer or copolymer of a monomer such as polyorganosiloxane, or a copolymer of the monomer with a copolymerizable monomer. As the copolymerizable monomer, aromatic vinyl compounds such as styrene and α-methylstyrene; methacrylic acid alkyl esters such as methyl methacrylate and ethyl methacrylate; alkyl having 1 to 8 carbon atoms such as methyl acrylate and ethyl acrylate.
Acrylic acid alkyl ester; vinylcyanide compounds such as acrylonitrile and methacrylonitrile; allyl acrylate, allyl methacrylate, 1,3-butylene dimethacrylate, 1,4-butanediol diacrylate, divinylbenzene and the like.

The hard polymer-forming monomer used in the graft polymerization in the graft polymerization tank is styrene,
Examples thereof include aromatic vinyl compounds such as α-methylstyrene; methacrylic acid alkyl esters such as methyl methacrylate, ethyl methacrylate and butyl methacrylate; vinyl cyan compounds such as acrylonitrile and methacrylonitrile. These monomers may be used alone or in combination of two or more.

In the graft polymerization tank, 0.01 to 10 parts by weight of an emulsifier, based on 100 parts by weight of the rubber-like polymer,
It is preferable to add 0.5 to 5 parts by mass and 0.1 to 10 parts by mass of an initiator, and to carry out emulsion polymerization. As the emulsifier, for example, an alkenyl succinate, a phosphoric acid ester salt, a fatty acid salt, a sulfuric acid ester salt, an ether carboxylic acid or the like is used. Examples of the initiator include peroxides such as benzoyl peroxide, cumene hydroperoxide and hydrogen peroxide; azo compounds such as azobisisobutyronitrile; persulfate compounds such as ammonium persulfate and potassium persulfate; A redox initiator or the like composed of a combination of a perchloric acid compound, a perboric acid compound or a peroxide and a reducing sulfoxy compound is used. Further, as a chain transfer agent, n-dodecyl mercaptan, t
You may use mercaptans, such as ert-dodecyl mercaptan, n-octyl mercaptan, n-tetradecyl mercaptan, and n-hexyl mercaptan.

In the coagulation step, the aggregating agent used for aggregating the graft copolymer contained in the graft copolymer latex is selected depending on the kind and amount of the emulsifier, but is mainly a weak acid salt. In the case of an emulsifier, an organic acid or an inorganic acid is preferably used, and in the case of an emulsifier mainly containing other than those mentioned above, an organic salt or an inorganic salt is preferably used. Further, these are preferably used as an aqueous solution.

Examples of the organic acid include acetic acid, formic acid and acrylic acid, and examples of the inorganic acid include hydrochloric acid, sulfuric acid, phosphoric acid,
Examples include nitric acid and the like. Examples of the organic salt include sodium acetate, calcium acetate, potassium formate, calcium formate, and the like, and examples of the inorganic salt include sodium chloride, potassium chloride, calcium chloride, magnesium chloride, sodium sulfate, magnesium sulfate, and the like.

The heat treatment temperature in the third and fourth tanks is preferably 80 ° C. or higher, more preferably 90 ° C. or higher, and the heat treatment time is preferably 10 minutes or longer, more preferably about 20 to 30 minutes. . If the heat treatment temperature is less than 80 ° C. or the heat treatment time is less than 10 minutes, the moisture content of the dehydrated product (dehydrated cake) obtained will be high, and the drying process will take a long time, resulting in poor production efficiency. This may lead to a decrease in productivity such as an increase in manufacturing cost.

The amount of washing water in the vacuum filter 11 is
It is appropriately set depending on the amount and type of the graft copolymerized slurry and is not particularly limited. Also, the water temperature of the wash water is
Although not particularly limited, it is usually in the range of 10 to 80 ° C. Dehydration in the vacuum filter 11 is performed under the condition that the moisture content of the obtained wet powder is usually in the range of 50 to 150% by mass.

The dehydration in the preliminary dehydrator 30 is not particularly limited, but it is preferable that the dehydration is performed in the belt press dehydrator 40 under the condition that the water content of the hydropolymer is in the range of 30 to 80% by mass. When the water content of the water-containing polymer is less than 30% by mass, the powder compacted by receiving pressure becomes hard and the powder properties may be impaired. On the other hand, if the water content of the water-containing polymer exceeds 80% by mass, the water content may be so large that stable dehydration may not be possible. Here, the moisture content is about 5 g of wet powder or water-containing polymer, which is precisely weighed ( _WW ).
After one hour air drying to dry mass at 180 ℃ (W _D)
Is a value obtained by the following formula. Water content (mass%) = _{[(W W -W D) / W} D ] × 100

The surface pressure of the belt press dehydrator 40 is 0.5.
To 5.0 MPa, preferably 1.0 to 4.0 MPa, and more preferably 2.0 to 3.0 MPa. The surface pressure is 0.
If it is less than 5 MPa, dehydration may be insufficient.
On the other hand, when the surface pressure exceeds 5.0 MPa, the pressure applied to the polymer becomes too large and the powder is deformed, which may impair the powder properties.

According to the apparatus and method for producing the emulsion-polymerized polymer described above, since the water-containing polymer is dehydrated by the belt press dehydrator 40, it is dehydrated under milder conditions than dehydration by the conventional centrifugal dehydrator. It is possible to suppress the deformation of the polymer particles due to the dehydration treatment. Further, since the polymer slurry is preliminarily dehydrated before the dehydration treatment by the belt press dehydrator 40, the dehydration efficiency by the belt press dehydrator 40 can be maintained at the same level as that by the conventional centrifugal dehydrator. it can.

The washing / dehydrating means in the apparatus for producing an emulsion-polymerized polymer of the present invention is not limited to the one shown in the drawings as long as it is a means for dehydrating an object to be dehydrated by a belt press dehydrator. For example, the polymer slurry from the reslurry tank 12 may be directly supplied to the belt press dehydrator 40 to dehydrate the polymer slurry. However, from the viewpoint of dehydration efficiency and the like, in the present invention, it is preferable to perform preliminary dehydration before dehydration by the belt press dehydrator.

The pre-dewatering machine is not limited to the one shown in the figure as long as it can dehydrate the polymer slurry to obtain the water-containing polymer. As a preliminary dehydrator, for example,
A Panevis filter can also be used.

[0039]

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. Further, in this example, the water content of the hydrous polymer obtained by the preliminary dehydrator and the dehydration product obtained by the belt press dehydrator, and the bulk density of the dried polymer were evaluated by the following methods.

[Moisture Content] Water-containing polymer (or dehydrated product)
After precisely weighed approximately 5g _(W W), and 1 hour hot-air drying at 180 ° C. to determine the dry mass (W _D), it was determined by the following equation. With water content (mass%) = _{[(W W -W D) / W} D ] × 100 [Bulk Density] The bulk density meter, determined by weighing the mass of emulsion polymerization type polymer 100 cm ³ obtained after drying It was

[Production of Polymer Slurry] The polymer slurry used in this example was produced as follows. (Polymer slurry A) In a reactor, 85 parts of methyl methacrylate, 15 parts of butyl methacrylate, tert-
After 0.003 parts of dodecyl mercaptan, 1.5 parts of potassium alkenyl succinate and 190 parts of deionized water were charged and the inside of the reactor was replaced with nitrogen, the temperature was started while stirring the inside of the reactor. When the temperature in the reactor reached 40 ° C, 2.0 parts of potassium persulfate and 1 part of deionized water were added.
Polymerization was initiated by charging 0 parts of the mixture into the reactor. Polymerization was started with stirring, and after the completion of polymerization, the polymer latex was held for 200 minutes, and then the obtained polymer latex was taken out from the reactor. A 0.2% sulfuric acid aqueous solution was added to the obtained polymer latex to coagulate the polymer, and the polymer was coagulated by heat treatment at 90 ° C. to obtain a polymer slurry A.

(Polymer Slurry B) 2 parts of tetraethoxysilane, 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and 97.5 parts of octamethylcyclotetrasiloxane are mixed to prepare siloxane mixture 1
I got 00 parts. To 200 parts of distilled water in which 1 part each of sodium dodecylbenzene sulfonate and dodecylbenzene sulfonic acid was dissolved, 100 parts of the above siloxane mixture was added, and after preliminarily stirring at 10,000 rpm with a homomixer, 300 kg / cm ² of a homogenizer was used. It was emulsified and dispersed by pressure to obtain an organosiloxane latex. This latex was transferred to a separable flask equipped with a condenser and a stirring blade, and the mixture was stirred and mixed for 8 hours.
After heating at 0 ° C. for 5 hours, the mixture was allowed to stand 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-liter stainless steel polymerization device 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. 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. Next, the obtained graft copolymer latex was dropped into 400 parts of hot water containing 1.5% of calcium chloride and coagulated to obtain a polymer slurry B.

(Polymer Slurry C) 99 parts of 2-ethylhexyl acrylate and 1 part of allyl methacrylate were mixed to obtain 100 parts of a (meth) acrylate monomer mixture. The above (meth) acrylate monomer mixture 1 was added to 300 parts of distilled water in which 1 part of alkenyl succinic acid dipotassium salt was dissolved.
After adding 00 parts and preliminarily stirring at 10,000 rpm with a homomixer, 300 kg / c with a homogenizer
It was emulsified and dispersed at a pressure of m ² to obtain a (meth) acrylate emulsion.

This emulsion was transferred to a separable flask equipped with a condenser and a stirring blade, the inside of the flask was replaced with nitrogen, and the emulsion was heated with mixing and stirring, and when it reached 70 ° C., it was dissolved in a small amount of water. After adding 1 part of potassium sulfate, the mixture was allowed to stand at 70 ° C. for 5 hours to complete the polymerization to obtain a latex of acrylic rubber (B-1). The polymerization rate of the obtained latex of acrylic rubber (B-1) was 98.5%, and the average particle size was 0.19 μm. Also, this latex was coagulated with ethanol, and the coagulated product was dried to obtain a solid product.
It was extracted at 0 ° C for 12 hours and the gel content was measured to be 9
It was 1.4 mass%.

1 latex of acrylic rubber (B-1)
Twenty parts were collected and put into a separable flask equipped with a stirrer, 205 parts of distilled water was added thereto, the inside of the flask was replaced with nitrogen, and then the temperature was raised to 50 ° C. In addition, 53.9 parts of n-butyl acrylate, 1.1 parts of allyl methacrylate, and te which are the constituents of the acrylic rubber (B-2).
A mixed solution of 0.22 parts of rt-butyl hydroperoxide was charged and stirred for 30 minutes, and this mixed solution was permeated into the latex particles of the acrylic rubber (B-1). 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 at an internal temperature of 70 ° C. Polymerization was completed by holding for 2 hours to obtain a latex of polyalkyl (meth) acrylate rubber. A part of this latex was collected and the average particle size of the polyalkyl (meth) acrylate rubber was measured to be 0.24 μm. Also, this latex is dried to obtain a solid matter, which is dried with toluene at 90 ° C for 12 hours.
It was extracted for 9 hours and the gel content was measured to be 97.3% by mass.
Met.

A mixed solution of 0.06 parts of tert-butyl hydroperoxide and 15 parts of methyl methacrylate was added dropwise to the latex of the polyalkyl (meth) acrylate rubber at 70 ° C. for 15 minutes, and then 70 ° C.
Was maintained for 4 hours to complete the graft polymerization on the polyalkyl (meth) acrylate rubber to obtain a latex of the graft copolymer. The polymerization rate of methyl methacrylate is
It was 96.4%. The latex of the obtained graft copolymer was dropped into 200 parts of hot water containing 1.5% by weight of calcium chloride and coagulated to obtain a polymer slurry C.

Example 1 Using the vacuum filter 11 shown in FIG. 1 as a vacuum filter, the polymer slurry A was washed and dehydrated. The supply amount of Polymer Slurry A to the vacuum filter is 1000 kg / hr, and the water amount of the first-stage washing water is 3000 L / hr, and the water amount of the second-stage washing water is 2
000 L / hr. Operation of the vacuum pump is 100k
Pa was performed under reduced pressure. Wash water temperature is 20
℃ was made.

The wet powder having a water content of 140% by mass obtained by the vacuum filter 11 is supplied to the reslurry tank 12, where 1000 parts of water is added to 100 parts of the wet powder to make a polymer slurry again. Slurry feed pump 13
Was supplied to the preliminary dehydrator 30 and dehydrated by vacuum dehydration to obtain a water-containing polymer having a water content of 101% by mass.

Subsequently, the water-containing polymer is supplied to the belt press dehydrator 40, and the endless upper filter cloth 44 and the lower filter cloth 4 are arranged so as to face each other so that the intervals become narrower.
It was sandwiched between 1 and pressed for dehydration to obtain a dehydrated product (dehydrated cake) having a water content of 30% by mass. As a belt press dehydrator,
Tsukishima Kikai Co., Ltd. press roll filter S3P
Using 3.2000, the surface pressure was set to 3.0 MPa to perform dehydration treatment.

The water content of the water-containing polymer obtained by the preliminary dehydrator and the dehydration content of the dehydrated product obtained by the belt press dehydrator were measured. The results are shown in Table 1. Further, the dehydrated product was dried using a flash dryer and a fluid dryer. As a flash dryer, the pipe diameter is 810 mm, the acceleration portion pipe diameter is 500 mm, and the length is 2.
9.7m, internal volume 12.95m ³ , inlet blower capacity 450
m ³ / min, output blower capacity 580 m ³ / min, actual operating air volume 430 m ³ / min, capacity 380 kg water / h
The one of r was used. As a fluid dryer, floor area is 10m
² , ceiling height 1200mm, weir height 30cm, number of weirs 8, inlet blower capacity 170 + 120m ³ / min, outlet blower capacity 580m ³ / min, actual operating air volume 170m ³
/ Min, capacity 160 kg water / hr was used. The amount of dried dehydrated product was 50 kg, the air-flow drying time was 5 minutes, and the fluidized drying time was 60 minutes. The bulk density of the polymer after fluidized drying was measured. The results are shown in Table 1.

Example 2 Example 1 was repeated except that polymer slurry B was used as the polymer slurry to be washed and dehydrated.
An emulsion polymer was obtained in the same manner as in. Table 1 shows the water content of the water-containing polymer obtained by the preliminary dehydrator and the dehydration product obtained by the belt press dehydrator, and the bulk density of the polymer after drying.

Example 3 Example 1 was repeated except that the polymer slurry C to be washed and dehydrated was polymer slurry C.
An emulsion polymer was obtained in the same manner as in. Table 1 shows the water content of the water-containing polymer obtained by the preliminary dehydrator and the dehydration product obtained by the belt press dehydrator, and the bulk density of the polymer after drying.

[Comparative Example 1] The same procedure as in Example 1 was repeated except that the P-60 / 2 centrifugal dehydrator manufactured by Tsukishima Kikai Co., Ltd. was used in place of the preliminary dehydrator 30 and the belt press dehydrator 40. Thus, an emulsion polymer was obtained. The amount of the dehydrated polymer slurry was 50 kg, the rotation speed of the centrifugal dehydrator was 1200 rpm, and the water content of the dehydrated product obtained by the centrifugal dehydrator and the bulk density of the dried polymer are shown in Table 1.

[Comparative Example 2] The same procedure as in Example 2 was carried out except that a P-60 / 2 centrifugal dehydrator manufactured by Tsukishima Kikai Co., Ltd. was used in place of the preliminary dehydrator 30 and the belt press dehydrator 40. Thus, an emulsion polymer was obtained. The amount of the dehydrated polymer slurry was 50 kg, the rotation speed of the centrifugal dehydrator was 1200 rpm, and the water content of the dehydrated product obtained by the centrifugal dehydrator and the bulk density of the dried polymer are shown in Table 1.

[Comparative Example 3] The same operation as in Example 3 was carried out except that a P-60 / 2 centrifugal dehydrator manufactured by Tsukishima Kikai Co., Ltd. was used in place of the preliminary dehydrator 30 and the belt press dehydrator 40. Thus, an emulsion polymer was obtained. The amount of the dehydrated polymer slurry was 50 kg, the rotation speed of the centrifugal dehydrator was 1200 rpm, and the water content of the dehydrated product obtained by the centrifugal dehydrator and the bulk density of the dried polymer are shown in Table 1.

[0058]

[Table 1]

As is clear from Table 1, in the case of the same polymer slurry, the bulk density of the emulsion-polymerized polymer obtained after drying was higher than that after the dehydration treatment by the centrifugal dehydrator, that by the belt press dehydrator. It can be seen that the ones that have performed are higher.

[0060]

Industrial Applicability As described above, the method for producing an emulsion polymerization-based polymer of the present invention comprises dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by an emulsion polymerization method, and then drying it. In the method for producing an emulsion polymerization type polymer to be used, since it is a method of dehydrating the polymer slurry with a belt press dehydrator,
It is possible to obtain a polymer having a high bulk density after drying, with little deformation of polymer particles due to dehydration treatment.

Further, the method for producing an emulsion polymerization type polymer according to the present invention is a method for producing an emulsion polymerization type polymer in which a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by the emulsion polymerization method is dehydrated and then dried. In the manufacturing method, the water-containing polymer obtained by preliminary dehydration of the polymer slurry, because it is a method of dehydrating with a belt press dehydrator, while maintaining the same dehydration efficiency as dehydration with a conventional centrifugal dehydrator, by dehydration treatment It is possible to obtain a polymer having a small deformation of polymer particles and a high bulk density after drying.

Further, the apparatus for producing an emulsion polymerization type polymer of the present invention is a belt press dehydration for dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by an emulsion polymerization method or a water-containing polymer obtained therefrom. Since it is equipped with a machine, deformation of polymer particles due to dehydration treatment is small, and a polymer having a high bulk density after drying can be obtained. In addition, if a preliminary dehydrator is installed in the preceding stage of the belt press dehydrator, while maintaining the same dehydration efficiency as the dehydration by the conventional centrifugal dehydrator, there is little deformation of the polymer particles due to the dehydration treatment, and after drying, A polymer having a high bulk density can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a washing / dehydrating means in an apparatus for producing an emulsion-polymerized polymer of the present invention.

FIG. 2 is a front view of an essential part showing an example of a belt press dehydrator.

FIG. 3 is a schematic configuration diagram showing an example of cleaning / dehydrating means in a conventional apparatus for producing an emulsion-polymerized polymer.

[Explanation of symbols]

30 preliminary dehydrator 40 belt press dehydrator 41 Bottom filter cloth 44 Upper filter cloth

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4J100 AB02Q AB03Q AB16Q AL03Q                       AL62Q AL75Q AM02Q AS02P                       AS03P AS07P CA01 CA04                       EA07 FA20 GC01 GC07 GC25                       GC37

Claims (7)

[Claims] 1. A method for producing an emulsion-polymerized polymer, comprising dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by an emulsion polymerization method, and then drying the polymer slurry, using a belt press dehydrator. A method for producing an emulsion-polymerization polymer, which comprises dehydration. 2. A method for producing an emulsion polymerization-type polymer, which comprises dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by an emulsion polymerization method, and then drying the polymer slurry. A method for producing an emulsion-polymerized polymer, which comprises dehydrating the water-containing polymer obtained by a belt press dehydrator. 3. The method for producing an emulsion polymerization-based polymer according to claim 2, wherein the water content of the water-containing polymer is 30 to 80 mass%. 4. A horizontal belt press dewatering machine as the belt press dewatering machine, wherein a polymer slurry or a water-containing polymer is sandwiched between endless upper filter cloths and lower filter cloths facing each other, and pressure dehydration is performed. 4. The method for producing an emulsion-polymerized polymer according to claim 1, wherein: 5. An emulsion polymerization system comprising a belt press dehydrator for dehydrating a polymer slurry obtained by aggregating a polymer contained in a polymer latex obtained by an emulsion polymerization method or a water-containing polymer obtained therefrom. Polymer manufacturing equipment. 6. The belt press dewatering machine is a horizontal belt press dewatering machine for sandwiching a polymer slurry or a water-containing polymer between endless upper filter cloth and lower filter cloth, which are arranged facing each other, and performing pressure dewatering. The apparatus for producing an emulsion-polymerized polymer according to claim 5, wherein 7. The apparatus for producing an emulsion polymerization type polymer according to claim 5, wherein a preliminary dehydrator is provided in front of the belt press dehydrator.