JPH0238401A - Continuous polymerization apparatus - Google Patents

Abstract

PURPOSE:To improve mixing efficiency with less stirring power by installing a rotatable shaft, equipped with specific flat blades, horizontally at the center of a horizontal cylindrical vessel which has a liq.-supplying port and a liq.- discharging port. CONSTITUTION:A rotatable shaft 7 penetrating through sealing parts 5, 6 at the both ends of the wall is installed in a horizontal cylindrical vessel 1 which has a liq.-supplying port 3 at the center part of the top, a liq.-discharging port 4 at the center of the bottom and an outer wall covered by a jacket 2. The shaft is equipped with uniformly perforated flat blades 8, 9 which, extending outwards radially from the shaft 7, are arranged at regular intervals and have many small holes 13 of which the sum of the areas is 1/3-1/2 of the area of the blades.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a polymerization reaction apparatus for continuously producing a high molecular weight polymer.

<Prior art> Solution polymerization and bulk polymerization are often used as methods for producing high molecular weight polymers. When dissolved in , it becomes a homogeneous liquid phase system, and as the polymerization reaction progresses, it becomes a highly viscous fluid.

A continuous polymerization reaction apparatus is used for such solution polymerization and bulk polymerization of a homogeneous liquid phase system that increases viscosity.

Conventionally known polymerization reactors include vertical cylindrical ones (see, for example, Japanese Patent Publication No. 55-29725, etc.)
and horizontal cylindrical ones (e.g., 1974-1274
(See Publication No. 89, etc.). Among these, horizontal cylindrical ones are known that have one, two, or multiple stirring shafts equipped with paddle-shaped stirring blades.

<Problems to be Solved by the Invention> In the production process of high molecular weight polymers, the viscosity of the reaction mixture is generally low at the beginning of the polymerization reaction, and the viscosity increases from the middle to the end of the polymerization reaction. Highly viscous reaction mixtures are difficult to mix uniformly, and product quality is affected by the selection of the polymerization reactor, so careful consideration is required when determining the structure. In addition, to uniformly mix high viscosity liquids, depending on the structure of the stirring blade, an extremely large stirring force may be required, and from the viewpoint of the material of the stirring blade, stirring power, etc., it is necessary to achieve efficient mixing performance. It is necessary to select a reactor with

However, in the conventional uniaxial polymerization reactor,
The mixing effect for highly viscous reactants was poor, and a phenomenon in which the reactants rotated together with the stirring shaft and stirring blades was observed, creating a dead space.

Therefore, in order to improve the drawbacks of the uniaxial polymerization reactor,
Various studies have been conducted. For example, one in which a fixed baffle plate is installed on the wall of a reaction vessel (Japanese Patent Laid-Open No. 41-64571
(see Japanese Patent Publication No. 45-20282), or a so-called stationary polymerization reactor without a central shaft in order to eliminate the dead space near the stirring shaft (see Japanese Patent Publication No. 45-20282).

However, these have problems in that their structures are extremely complex and their effects are insufficient.

In view of the above-mentioned problems, the present invention has a relatively simple structure, eliminates the drawbacks of conventional continuous polymerization reactors, and has the following advantages and a superior appearance. An object of the present invention is to provide a continuous polymerization reaction apparatus having a single rotating shaft.

(1) The structure is simple.

(2) Good stirring and mixing efficiency.

(3) The stirring power may be small.

(4) No dead space occurs.

<Means for Solving the Problems> In order to achieve the above object, the present invention provides a horizontal cylindrical container having a liquid supply port and a liquid discharge port, a rotating shaft provided horizontally at the center of the container, , a plurality of flat plate blades arranged at approximately equal intervals around the rotation axis, each extending radially outward from the rotation axis, and having a large number of small holes distributed approximately uniformly on the surface; The structure shall be equipped with the following.

Further, the total area of the small holes formed in the flat blade is set to be in the range of 1/3 to 1/2 of the area of the flat blade.

In the above configuration, the contents are moved upward or downward as each flat blade rotates, and at the same time, some of the contents slip through the many small holes provided on the flat blade surface and reach the back side of the flat blade. The mixture is remixed in a somewhat turbulent manner.

According to this, the structure is simple because it is uniaxial, there is no co-rotation, and the phenomenon of retention can be prevented, so that it is possible to efficiently stir and polymerize.

Polymerization reactions applicable to the continuous polymerization reaction apparatus according to the present invention include, for example, solution polymerization and bulk polymerization of polystyrene;
Bulk polymerization of polymethyl methacrylate, solution polymerization and bulk polymerization of acrylonitrile styrene resin, solution polymerization of acrylonitrile butadiene styrene (ABS) resin, solution polymerization of polybutadiene, solution polymerization of styrene butadiene rubber (SBR), ε- Polycondensation of 6-nylon using caprolactam as a raw material, polycondensation of 6,6-nylon using adipic acid and hexamethylene diamine as raw materials,
Solution polymerization of polyvinyl acetate, etc. In such a polymerization reaction, the reaction mixture becomes highly viscous at the end of the polymerization reaction, but when the continuous polymerization reaction apparatus according to the present invention is used, mixing efficiency is good and a uniform polymerization system can be obtained.

<Example> An example of the present invention will be described below based on the drawings, but the present invention is not limited to the following example unless it exceeds the gist thereof.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the present invention.

A horizontal cylindrical container 1 has its outer peripheral wall surrounded by a jacket 2 for temperature control, and has a liquid supply port 3 in the center area of the top.
A liquid discharge port 4 is formed in the center area of the bottom.

Inside the container 1, there is provided a rotating shaft 7 that rotatably penetrates both end walls of the container 1 via shaft seals 5 and 6, and a pair of flat blades 8 and 9 are attached radially around this rotating shaft 7. They constitute the paddle group N10. In this example, there is one pair of flat plate blades, but a plurality of flat plate blades may be arranged at approximately equal intervals around the rotation axis, and each may extend radially straight outward from the rotation axis.

The flat blades 8.9 have their edges close to the inner circumferential wall of the container 1, and have defective parts 11.1 at diagonally opposing parts.
2 is formed. The size and location of the defect area can vary widely. In addition, a large number of small holes 13 are formed on the plane of the flat blades 8.9, and the total area and position of the small holes 13 can be changed over a wide range, but the total area is 1 of the area of the flat blades 8.9. It is preferably in the range of /3 to 1/2.

Here, when the rotating shaft 7 is rotated by a drive device (not shown), the contents are moved upward or downward with the movement of each flat plate blade 8.9, and at the same time, some of the contents are
It passes through a large number of small holes 13 provided in the flat blade 8.9.
The mixture is remixed in a slightly turbulent manner on the back side of 9. Therefore, the flat plate H
8, 9 not only near the surface but also throughout the inside of the container 1,
A powerful and complex flow of contents will be formed.

This makes it possible to avoid co-circulation and stagnation of the contents, and to significantly improve the stirring effect and the reaction effect. In other words, this device has a better ability to stir and mix the reactants than conventional single-screw reactors, so the polymerization reaction can proceed efficiently and the quality of the resulting polymer is stable. and become excellent.

The effects of the device of the present invention over the conventional device will be shown below through experiments.

Comparative Example In a transparent acrylic horizontal cylindrical container with an inner diameter of 300 mm and a tank length of 400 mm, a blade with a blade width of 100 mm and a blade diameter of 294 mm was placed.
A stirring device equipped with a stationary blade (see Figure 2) was used as a comparative example.

Iodine (I2) and sodium thiosulfate (NazSzO:+) are added to a starch syrup aqueous solution with a viscosity of 200 poise in a container.
After separately supplying the two solutions in which each of
By measuring the time t (min) until decolorization with SzO3, the number of revolutions N required to complete mixing can be determined.
= n - t was calculated. The stirring torque was also measured.

The results showed that when N=100, about 80% of the entire contents of the container were decolored, but the contents in the center of the container remained colored, and N=
At 200, the color was finally completely bleached. Stirring torque is 0.75
Kgf-m (see Table 1).

The paddle device shown in FIG. 1 was installed in the same container as used in the comparative example, and an experiment was conducted in the same manner as in the comparative example to determine the number of rotations N required to complete mixing. As a result, the entire contents of the container were decolored at N=35. The stirring torque was 0.75 Kgf-m (see Table 1).

Therefore, it was confirmed that the apparatus according to the present invention requires fewer rotations to complete mixing than the apparatus used in the comparative example.

Table 1 <Effects of the Invention> As explained above, according to the apparatus of the present invention, the structure of the apparatus is simple, and the co-circulation of reactants near the stirring shaft and stirring blades, which is seen in conventional single-shaft reactors, is avoided. It also prevents stagnation and stagnation phenomena, and has an excellent ability to stir and mix reactants, allowing the polymerization reaction to proceed efficiently and resulting in stable and excellent quality of the resulting polymer. The industrial utility value of the present invention is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing one embodiment of the present invention, and FIG. 2 is a diagram of main parts of an apparatus used in a comparative example. ■ Container 3 Liquid supply port 4 Liquid discharge port 5° 6 Shaft seal 7 Rotating shaft 8° 9 Flat blade 10 Paddle device 12 ... Defect part 13 ... Small hole

Claims (2)

[Claims] (1) A horizontal cylindrical container having a liquid supply port and a liquid discharge port, a rotating shaft provided horizontally at the center of the container, and a rotating shaft arranged at approximately equal intervals around the rotating shaft, each radially extending from the rotating shaft. 1. A continuous polymerization reaction apparatus, comprising: a plurality of flat plate blades extending outward from each other and having a large number of small holes substantially uniformly distributed on a surface thereof. (2) The continuous polymerization reaction apparatus according to claim 1, wherein the total area of the small holes formed in the flat blade is in the range of 1/3 to 1/2 of the area of the flat blade.