JP4736079B2 - Method for producing powdered potassium acrylate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
TECHNICAL FIELD The present invention relates to a method for producing powdered potassium acrylate, and more particularly to a method for producing powdered potassium acrylate having a low water content, high fluidity, and free of agglomerates, and belongs to a chemical production technology. Is.
[0002]
[Prior art]
Potassium acrylate, which is a vinyl monomer, is a homopolymer, as well as copolymers obtained by copolymerization with various monomers. Thickeners such as aqueous paints, aqueous adhesives, and sealing agents It is used in various fields as a base for a haptic agent or an adhesion improver, a dispersant / binder for pigments and aggregates, an anti-settling agent, and a dispersion stabilizer for metal powder in dry batteries.
[0003]
In these applications, potassium acrylate is usually used as an aqueous solution, but in some applications, a powder form is required.
However, potassium acrylate is very hygroscopic, and the moisture-absorbed potassium acrylate is likely to be a lump, and the lumped potassium acrylate is very difficult to handle. There is a strong demand for improvement in the present situation that products that are sought and often mixed with difficult-to-handle lumps are often supplied.
[0004]
A method of obtaining powder from an aqueous solution of potassium acrylate is usually performed by a method of obtaining the powder through steps such as drying and pulverization.
As the drying method, a method of drying by attaching a potassium acrylate aqueous solution in the form of a thin film to the surface of the rotating drum or the upper surface of the rotating disk which has been heated to a high temperature and further to the gap between the two rolls through a heat medium such as steam. In addition, a drying method by spraying using a spray dryer or the like is employed.
[0005]
[Problems to be solved by the invention]
Powdered potassium acrylate produced by such a method is stored in an airtight container to obtain a product.
Therefore, the powdered potassium acrylate contained in the container is less likely to be absorbed and agglomerated during storage, but may be rapidly absorbed and agglomerated after opening the container. However, it also has a problem that it forms moisture-absorbing lumps and clogs the piping or makes it difficult to fill the container.
[0006]
In view of the present situation, the inventors of the present invention have made extensive studies on a method for producing powdered potassium acrylate in order to obtain a powder of potassium acrylate that is difficult to agglomerate.
As a result, the powdered potassium acrylate obtained by separating and drying from the aqueous solution was further brought into contact with a dry gas and subjected to drying treatment so that the water content was 200 ppm or less. It became difficult to agglomerate, and it was found that the agglomerate is rarely produced during the production process and when used as a product, and the present invention was completed.
[0007]
[Means for Solving the Problems]
According to the first aspect of the present invention,
A powdery potassium acrylate obtained by drying an aqueous solution of potassium acrylate having a solid content concentration of 10 to 70% by mass with a spray dryer is sent to a cyclone linked through the spray dryer and a pipe,
In the cyclone, the powdered potassium acrylate separated from the air containing water vapor is sent to the stock tank via the pipe,
In the stock tank, dry mixing with a dry gas having a dew point temperature of −20 ° C. or less and drying to a moisture content of 200 ppm or less produces smooth potassium acrylate with little moisture on the powder surface. ,
Obtained acrylic acid potassium, using the filling machine via a rotary valve which is attached to the stock tank, is powdery acrylic acid potash manufacturing method comprising <br/> be filled into containers moisture-proof .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, there is no particular limitation on the aqueous solution of potassium acrylate used.
Industrial acrylic acid may be simply neutralized with industrial caustic potash, and the solid content concentration is 10 to 70% by mass, more preferably 20 to 50% by mass for ease of handling. belongs to.
[0009]
The equipment used for the separation drying is to use SPRAY dryer.
[0010]
As the dry gas, air or an inert gas such as nitrogen or carbon dioxide and a mixture thereof are used.
Unless there is a special reason, air may be used. As the air, air from which water vapor has been removed with an air dryer or the like is used.
[0011]
There are two types of air dryers: a refrigeration type that condenses water vapor to dehumidify, and an adsorption type that adsorbs water vapor using an adsorbent.
In the adsorption type, there are a heat regeneration type and a non-heat regeneration type from the method of regenerating the adsorbent, but preferred for the production method of the present invention is that dry air with a low dew point temperature can be obtained at low cost with a simple device. It is an unheated regenerative adsorption air dryer.
[0012]
As the dry gas, usually dry air, one having a dew point temperature of −20 ° C. or lower is used.
[0013]
Hereinafter, an example of a manufacturing apparatus for powdered potassium acrylate according to the present invention using a spray dryer as an apparatus for separation and drying will be described with reference to FIG. 1, but the manufacturing apparatus is not limited to this embodiment. Absent.
[0014]
In FIG. 1, reference numeral 1 denotes a built-in vibrator (not shown), and an air disperser 2 at the top, a dry chamber for drying a raw potassium acrylate solution, and 3 a raw material supplied by a pump 4. An atomizer for supplying an aqueous solution of potassium acrylate to the dry chamber 1 in the form of a mist, 5 is an air heater, and the air taken in by the blower 6 is heated and supplied to the air disperser 2. Hot air is blown in a cyclone shape, and the spray dryer is constituted as a whole by such members.
[0015]
Reference numeral 7 denotes a cyclone that cooperates with the dry chamber 1 via the pipe 8 to separate the powdered potassium acrylate supplied from the dry chamber 1 and air containing water vapor, and 9 denotes the cyclone 7 via the pipe 10. in stock tank cooperating to rotary valve 11, while being attached to a vibrator (not shown), which in conjunction with the air dryer 13 via a pipe 12.
[0016]
14 is a bag filter that cooperates with the cyclone 7 via a pipe 15, and includes a wind exhauster 16 that separates fine powdered potassium acrylate and air supplied from the cyclone 7 via the pipe 15. The separated air is discharged to the outside through the exhaust fan 16.
[0017]
In order to produce powdered potassium acrylate using such a powder dryer as a main component, a powdered potassium acrylate production apparatus is supplied to the atomizer 3 with the raw material potassium acrylate solution fed by the pump 4. Then, it is sprayed and fed into the dry chamber 1 through the air disperser 2 .
At the same time, when air heated to a predetermined temperature by the air heater 5 is supplied to the air disperser 2 by the blower 6, the sprayed potassium acrylate aqueous solution and the heated air are integrally mixed by the air disperser 2. Then, it is sent into the dry chamber 1 and mixed by stirring and spray-dried.
[0018]
At that time, the water in the sprayed potassium acrylate aqueous solution is heated to become water vapor, whereby the potassium acrylate is powdered and sent to the cyclone 7 through the pipe 8 together with the air containing water vapor. Since the vibrator is attached in the chamber 1, the powdered potassium acrylate does not adhere to the peripheral wall.
[0019]
The air containing powdered potassium acrylate and generated water vapor sent to the cyclone 7 is separated into powdered potassium acrylate and air containing water vapor, and the powdered potassium acrylate is passed through the pipe 10. Although being sent to the stock tank 9, the fine powdered potassium acrylate is sent to the bag filter 14 through the pipe 15 together with air.
[0020]
The powdered potassium acrylate supplied to the stock tank 9 is supplied with dry air adjusted to a predetermined dew point temperature from the air dryer 13 via the pipe 12 to the stock tank 9. and powdery acrylic acid potash are mixed and contacted, powdery acrylic acid potassium silky is generated, is housed in a container by using a filling machine (not shown) through a rotary valve 11 is a product.
[0021]
Incidentally, sent to the bag filter 14, fine powdery acrylic acid potassium and air are separated in the bag filter 14, the air in the outside air by the exhaust fan 16, fine powdery acrylic acid Cali, Rotary It is taken out via the valve 11 and shipped as a product.
[0022]
[Action]
According to the method for producing potassium acrylate according to the present invention , the powder obtained by separating and drying from the aqueous solution is further contact-mixed with a dry gas having a dew point temperature of −20 ° C. or less in a stock tank, and the water content is 200 ppm or less. By forming the powdered potassium acrylate, the powdered potassium acrylate can be agglomerated by moisture absorption, not only in a sealed container, but also after opening or in a production apparatus that is relatively easy to mix with air. It is unlikely to occur and is very easy to handle both in use and in production.
[0023]
By the way, powdery acrylic acid potassium having such properties, although why Is not clear obtained, powdery acrylic acid potassium is 200ppm or less moisture prepared by this invention, the water to the powder surface It is almost nonexistent, and it is thought that the surface was made hydrophobic to some extent by dry air.
[0024]
【Example】
Hereinafter, the method for producing powdered potassium acrylate according to the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0025]
<Example 1>
An air disperser of 15,000 rpm together with an aqueous solution of potassium acrylate (concentration: 30% by mass) 40 kg / Hr obtained by neutralizing an aqueous solution of acrylic acid with caustic potash together with air 4 m ³ / min heated to a temperature of 260 ° C. It was sent to a dry chamber (processing capacity: 150 kg / h) having an inner diameter of 3,500 mm and a height of 2,000 mm using the zipper and dried.
Potassium acrylate dried in hot air and turned into powder was sent to a cyclone with a diameter of 300 mm by an air current at a temperature of 140 ° C. and separated from air.
[0026]
The powdered potassium acrylate separated from the air was sent from the bottom of the cyclone to a 1.5 m ³ stock tank.
The stock tank was separately supplied with air having a dew point temperature of −20 ° C. or less from two air dryers capable of producing 330 l / min of dry air, and was contact-mixed with powdered potassium acrylate.
The powdered potassium acrylate sent to the stock tank has a temperature of about 60 ° C., is cooled by contact mixing with dry air, and filled into a moisture-proof container without any problems by a filling machine. It was said.
[0027]
There was no lump in the obtained product, and no lump was recognized even in the inspection one month after filling, and it remained in powder form.
Further, the moisture content of the product was measured under the following conditions using the Karl Fischer method in an environment with a relative humidity of 40%, and was found to be 120 ppm.
[0028]
<Moisture content measurement conditions (Karl Fischer method)>
Using a moisture measuring device manufactured by Mitsubishi Kasei Co., Ltd. (CA-06 type), a precisely weighed sample was placed in the vaporization chamber of the water vaporizer (VA-06 type) connected to the device, and the set temperature was 150 ° C., Measurement was performed at a nitrogen flow rate of 200 ml / min.
As the Karl Fischer moisture measurement reagent, Aquamicron AX and Aquamicron CXU manufactured by Mitsubishi Kasei Co., Ltd. were used.
[0029]
<Comparative Example 1>
Powdered potassium acrylate was prepared in the same manner as in Example 1 except that contact mixing of powdered potassium acrylate and dry air in a stock tank was not performed.
When the moisture content of this potassium acrylate was measured by the Karl Fischer method in the same manner as in the Example, it was 2850 ppm.
The resulting powdered potassium acrylate has a tendency to agglomerate in stock tanks, and products filled only with powder that is not agglomerated can also be agglomerated in a moisture-proof container in a short time and partially polymerized. However, the powder could not be dispersed and the quality deteriorated rapidly.
[0030]
【The invention's effect】
According to the method for producing powdered potassium acrylate of this invention, an aqueous solution of potassium acrylate having a specific concentration as a raw material is supplied to a stock tank with powdered potassium acrylate obtained by once drying with a spray dryer, In this stock tank, by contacting and mixing with a dry gas having a dew point temperature of −20 ° C. or less, a powdery potassium acrylate having a moisture content of 200 ppm or less and almost no moisture on the surface is obtained. As a matter of course, it is possible to easily and easily produce powdered potassium acrylate which is difficult to absorb moisture during the production process and is very easy to handle even when used in a sealed container.
[0031]
Further , it is not certain what the powdered potassium acrylate obtained by the method for producing powdered potassium acrylate of the present invention is, but it is difficult to agglomerate even after long-term storage, and the obtained powder Jo acrylic acid potash, water at 200ppm or less, and the surface of the powder can provide water most lumps Joka less prone excellent powdery acrylic acid potash the absence.
[Brief description of the drawings]
FIG. 1 is a schematic process explanatory diagram of a method for producing powdered potassium acrylate according to the present invention.
[Explanation of symbols]
1 Dry chamber 2 Air disperser 3 Atomizer 4 Pump 5 Air heater 6 Blower 7 Cyclone 8, 10, 15 Piping 9 Stock tank
11 Rotary valve
13 Air dryer
14 Bug filter

Claims (1)

A powdery potassium acrylate obtained by drying an aqueous solution of potassium acrylate having a solid content concentration of 10 to 70% by mass with a spray dryer is sent to a cyclone linked through the spray dryer and a pipe,
In the cyclone, powdered potassium acrylate separated from air containing water vapor is sent to a stock tank via a pipe,
In the stock tank, dry mixing with a dry gas having a dew point temperature of −20 ° C. or less and drying to a moisture content of 200 ppm or less produces smooth potassium acrylate with little moisture on the powder surface. ,
Obtained acrylic acid potassium, the stock tank is used filling machine via a rotary valve was attached to the powdery acrylic acid potassium method for producing according to claim <br/> be filled into containers moisture-proof.

Images