JP2741208B2 - Reaction / mixing degassing method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for efficiently degassing a polymer compound such as a resin mixed with air bubbles and other viscous fluids.

[Conventional technology]

Plastic materials and the like are produced by kneading and mixing various raw materials with a stirring mixer or the like, or by blending. Therefore, the produced plastic material contains a myriad of air bubbles and must be degassed before molding the resin molded product.

Conventionally, bubbles contained in a viscous fluid such as a plastic material are expanded by depressurizing the inside of a closed container, floated on the surface of the fluid by the buoyancy of the bubbles themselves, and escape to the outside.

[Problems to be solved by the invention]

Such a degassing method waits for the gas to float naturally on the surface of the viscous fluid due to the buoyancy of the bubble itself and wait for degassing, so it takes a long time to finish degassing, and the productivity is poor. Was. In addition, not only is it difficult to deaerate the portion where the fluid contacts the inner wall of the container, but if the fluid has a high viscosity, bubbles are difficult to move and grow, and cannot be deaerated unless the inside of the container is set to a high vacuum state. There was a problem.

[Means for solving the problem]

The present invention has been made to solve such problems, and the gist of the reaction / mixing degassing method according to the present invention is that the reaction / mixing deaeration method is carried out in the same closed vessel equipped with a spiral ribbon stirring blade. Stir two or more resin raw materials,
After kneading or reacting to obtain a viscous fluid, the obtained viscous fluid is stirred and depressurized at a speed that does not involve air, and bubbles mixed in the viscous fluid are allowed to grow, and from the viscous fluid, To degas.

Another point of the reaction degassing method according to the present invention is that, in the same closed vessel equipped with a spiral ribbon stirring blade, two or more resin materials are stirred at a high speed, and kneaded or reacted. After obtaining the viscous fluid, the obtained viscous fluid is agitated at a speed that does not involve air, and the pressure is reduced, and the number of revolutions of the agitation is appropriately reduced to grow bubbles mixed in the viscous fluid. To degas from the viscous fluid.

Further, the gist of the apparatus for carrying out the method of the present invention includes a closed container, a pressure reducing means for reducing the pressure in the closed container, and a spiral ribbon stirring for uniformly stirring the viscous fluid in the closed container. It is provided with a stirring means having a blade shape, and a rotation driving means provided with a rotation speed changing means for rotating the stirring means and changing the rotation speed of the stirring means.

[Action]

According to the present invention, the viscous fluid in the closed vessel is gradually stirred by the stirring means at such a speed that air is not entrained, and the pressure in the closed vessel is reduced by the pressure reducing means. The bubbles mixed in the viscous fluid expand as the pressure in the closed container is reduced, and as the viscous fluid is agitated by the agitating means, the respective bubbles are integrated and the size of the bubbles grows. Bubbled bubbles quickly exit the viscous fluid.

In addition, even with a highly viscous fluid, expansion is promoted by stirring the trapped bubbles from the outside,
Further, the bubbles are integrated, and the grown bubbles rise due to their buoyancy, exit the surface of the fluid, and are degassed.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

In FIG. 1, reference numeral 10 denotes an airtight container having an airtight structure. The airtightness of the resin material 12 which is a viscous fluid supplied into the airtight container 10 as well as air is prevented from leaking. A plurality of resin materials are placed in the closed container
Are provided at the bottom, and a discharge pipe 18 for discharging the resin material 12 which has been compacted, polymerized or blended in the closed vessel 10 to the outside.
Are arranged.

A spiral ribbon stirring blade 22 attached to a shaft 20 is housed inside the closed container 10, and the ribbon stirring blade 22 is rotationally driven via the shaft 20 by a rotation driving device 24. The rotation driving device 24 is provided with a rotation speed changing device (not shown), and when the closed container 10 functions as a reaction tank for polymerization or blending, the ribbon stirring blade 22 is rotated at a high speed. When the closed container 10 functions as a deaeration tank, the ribbon stirring blade 22
Is designed to rotate at low speed.

Further, an intake pipe 26 is provided at the upper part of the closed vessel 10, and the air in the closed vessel 10 is exhausted through the suction pipe 26 by a vacuum pump 30 driven by a motor 28. The internal pressure is reduced.

In the apparatus having such a configuration, various resin raw materials are supplied into the closed vessel 10 from the supply pipes 14, 16,..., Respectively, in a fixed amount, and then reacted while being stirred by the ribbon stirring blades 22. Since the manufactured resin material 12 contains a large amount of bubbles generated by stirring or the like, the resin material 12 is then degassed from the resin material 12.

The degassing from the resin material 12 is performed by lowering the rotation speed of the shaft 20 by the rotation speed changing device of the rotation drive device 24 and gradually stirring the resin material 12 by the ribbon stirring blades 22, and the inside of the sealed container 10 by the vacuum pump 30. This is performed by sucking the air through the intake pipe 26 and depressurizing the inside of the sealed container 10. That is, as the pressure in the closed container 10 is reduced, the air bubbles mixed in the resin material 12 are expanded, the buoyancy increases, and the resin material is
As the 12 is agitated, the bubbles overlap with the bubbles to form a single cell.
The resin material 12 rises to the surface of the substrate 12 and is quickly degassed. At this time, air bubbles that have adhered to the inner wall of the closed container 10 in contact with the resin material 12 are stirred by the ribbon stirring blade 22 to be separated from the inner wall, and are easily degassed. In addition, since the resin material is highly viscous, even if the bubbles are strongly confined, the bubbles can be easily expanded by stirring, and the size of a plurality of bubbles can be integrated to grow. And even a highly viscous resin material is quickly degassed.

Although one embodiment of the present invention has been described in detail, the present invention is not limited to the above-described embodiment.

For example, the stirring blade is not limited to a spiral ribbon stirring blade, and may be, for example, a shaft in which a plurality of radially protruding stirring blades are arranged on a shaft. Furthermore, it is also possible to provide a configuration in which the viscous fluid is agitated by applying vibration to the viscous fluid. The point is that any material that can stir the viscous fluid almost uniformly without involving new air may be used.

The rotation speed of the stirring blade is determined by the shape and diameter of the stirring blade, in other words, the peripheral speed, and further, the viscosity of the viscous fluid, and a rotation speed that does not involve any new air is selected.

In addition, the structure of the closed container is not limited at all, and the method and apparatus of the present invention can be applied to the production of processed foods having a fluidity other than the viscous fluid such as a resin, and particularly, the viscosity is high. The present invention can be implemented in various modified, improved, or modified forms based on the knowledge of those skilled in the art without departing from the spirit of the present invention, such as being suitable for a fluid.

Example 1 A deaerator according to the present invention was installed in a polymerization reactor (inner diameter: 750 mm). Approximately 2500po viscosity in polymerization reactor
ise polyamic acid was produced. The produced polyamic acid was in a cloudy state due to bubbles.

The clouded polyamic acid was stirred at a rotation speed of 15 rpm by a spiral ribbon stirring blade (outer diameter: 735 mm) in a closed vessel of the polymerization reactor, and the pressure in the closed vessel was reduced to -755 mm / Hg. As a result, it was confirmed that a transparent polyamic acid was obtained in 30 minutes and degassed.

When the ribbon stirring blade was rotated at a rotation speed of 30 rpm or more, air was entrained and bubbles were generated. In addition, when rotated at a speed of 10 rpm or less, it took about 1 to 2 hours to obtain a transparent polyamic acid.

Comparative Example 1 The polyamic acid obtained under the same conditions as in Example 1 was degassed in a stationary state and the pressure in the closed vessel was reduced to -755 mm / Hg.

As a result, it took 5 hours to obtain a transparent polyamic acid.

〔The invention's effect〕

The present invention is to decompress the viscous fluid mixed with air bubbles in a closed container and gradually agitate the deaerated fluid, thereby greatly reducing the time required for the viscous fluid to be completely deaerated. It shortens and increases productivity. In addition, by stirring, the distribution state of the density and viscosity of the viscous fluid can be made uniform at the same time as the deaeration, and further, it can be expected that there is no need to reduce the pressure to a high vacuum. Play.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example for explaining a degassing method and apparatus according to the present invention. 10; airtight container 12; resin material (viscous fluid) 22; ribbon stirring blade (stirring means) 24; rotary drive device 26; suction pipe 30; vacuum pump (pressure reducing means)

Claims (3)

(57) [Claims] 1. A viscous fluid is obtained by stirring, kneading or reacting two or more resin raw materials in the same closed vessel equipped with a spiral ribbon stirring blade to obtain a viscous fluid. A reaction / mixing degassing method comprising stirring and depressurizing at a speed that does not involve air, growing bubbles mixed in the viscous fluid, and degassing from the viscous fluid. 2. A viscous fluid is obtained by stirring, kneading or reacting two or more kinds of resin raw materials at a high speed in the same closed container equipped with a spiral ribbon stirring blade to obtain a viscous fluid. The reaction is characterized in that the body is agitated at a speed that does not involve air, and the pressure is reduced, and the number of revolutions of the agitation is appropriately reduced, so that bubbles mixed in the viscous fluid are grown and deaerated from the viscous fluid. -Mixed degassing method. 3. A closed vessel, a pressure reducing means for reducing the pressure in the closed vessel, a stirring means in the form of a spiral ribbon stirring blade for uniformly stirring the viscous fluid in the closed vessel; A reaction / mixing degassing apparatus comprising: a rotation driving means provided with a rotation number changing means for rotating the means and changing the rotation number of the stirring means.