JPS58193109A - Method for coarsely crushing water-containing high molecular weight water-soluble polymers - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for crushing a water-soluble polymer having a high molecular weight.

Water-containing high molecular weight water-soluble polymers (hereinafter referred to as polymerization reactants) such as acrylamide and acrylic acid (salts) obtained by aqueous solution polymerization are usually crushed into small particles that are advantageous for drying. , dry.

Through product manufacturing processes such as pulverization, it is made into a dry powder product that is convenient for transportation and storage, and is used as a paper strength enhancer. Polymer flocculant.

Thickener. Oil recovery agent. It is widely used in various fields such as electrolytic refining chemicals.

By the way, the physical properties of such polymerization reactants are mainly controlled by the monomer concentration of the starting polymerization raw material (aqueous solution). For example, when the monomer concentration is 10% by weight or less, it is a viscous aqueous solution, but as the monomer concentration increases, it gradually becomes more viscous, and when it is around 25% by weight, it becomes soft.
Further, if the amount is 30% by weight or more, it becomes a completely rubber-like elastic solid.

Therefore, in terms of production costs, particularly drying costs, it is advantageous to obtain a polymerization reactant in the form of a rubber-like elastic solid starting from a monomer concentration as high as possible. However, although the polymerization reactant is in the form of a rubber-like elastic solid, it cannot be treated as a normal rubber-like elastic solid because it has adhesive properties between itself and other substances that are unique to water-containing high molecular weight water-soluble polymers. The product production process, especially the crushing process, involves difficult problems.

That is, conventionally, the most common method for such a crushing process is to use a cutting mill as shown in attached Figure 1, which is the only method applicable to industrial large-scale crushing of rubber-like elastic solids. It is.

As is clear from Fig. 1, this method uses a casing (
A polymerization reactant, that is, a coarse crushing material is fed from the population (11) into a coarse crushing passage surrounded by a typical five-blade rotary blade (3) and the rotary blade (3). ), the coarse crushing material is subjected to coarse crushing processing in a crushing chamber (5) containing a typical two-blade case fixed blade (4) provided in the passage, and the lower part is processed. Screen with many holes through which particles pass (6)
This is carried out by sending the liquid through the lower outlet (2). Note that (7) in Figure 1 indicates a scattering prevention member.

However, this method has the drawback that significant adhesion and clogging occur inside the cutting mill, and unless the throughput is kept low, it cannot be processed into small particles that are advantageous for drying.

That is, the conventional coarse crushing method described above is a method of producing coarsely crushed particles in the form of small particles in terms of drying speed, and the pore size of the screen is 5 to 6.
This is a coarse crushing method in which the throughput is kept extremely low as Wφ and the process is performed in one stage. If the screen pore size is increased, the processing capacity will increase, but the shape of the treated granules will become coarse, which is disadvantageous in terms of drying speed. Furthermore, if the feed rate is increased while the screen pore diameter is 5 to 6 .phi., continuous processing will not be possible for a short period of time.

Therefore, this method of suppressing the feed rate to a low level to form small particles is extremely disadvantageous on an industrial scale because it requires a large number of crushers.

On the other hand, to counter this, there is a method to reduce the monomer concentration of the polymerization reactant and make it soft enough to be treated with an extruder etc., which is one of the other industrial solutions. However, this method is disadvantageous in terms of drying and dehydration costs due to the high water content of the polymerization reactant, and also cannot be said to be sufficient in terms of processing capacity.

Therefore, the present inventor focused on the above-mentioned problems and conducted intensive studies to improve them, and as a result, the present inventor developed a rubber-like elastic solid with a considerably low water content, starting from the adhesive Takashi Tsumar concentration. The present inventors have discovered that even polymerization reactants can be sufficiently crushed into small particles in large quantities, which are advantageous for drying, by improving the crushing treatment means, and have arrived at the method of the present invention.

That is, the present invention is characterized in that when the main polymerization reactant is roughly crushed using a cutting mill,
Two cutting mills are connected and arranged in upper and lower stages, and the lower screen hole diameter is made smaller than the upper screen hole diameter, and each stage sequentially performs a particle-reducing action as the required hole diameter, and also reduces the size of the treated granules in the lower stage. By suctioning and ventilating from the outlet, an air flow in the same direction as the flow of the treated granules is generated through the holes in each stage of the screen, the crushing chamber is ventilated and cooled, and the synergistic effect of these processes stably coarsens the particles into small particles. This is a method of crushing.

Hereinafter, specific embodiments of the crushing method of the present invention will be described in detail based on the accompanying drawings.

FIG. 2 is an explanatory diagram of the coarse crushing method of the present invention using a cutting mill. Show it.

Therefore, in this figure, regarding the upper stage, that is, the first stage cutting mill (N), (llf1 is the inlet of the polymerization reactant, that is, the coarsely crushed raw material, and the arrow indicates the direction of the inlet and the flow direction of the suction draft airflow, In addition, <2f indicates the flow direction of the airflow as well as the flow direction of the treated granules in the first stage, (3) represents the rotating blade in the case of a typical five-blade case, and (4) represents the rotary blade in the case of two blades. (5) shows the crushing chamber, and (6) shows the screen with many holes through which the processed granules, that is, the coarse granules, pass through in the first stage.On the other hand, regarding (B) in the figure, , (31', (4f
, (5r, (6)'Ic Tsurezoshiz Step (7)f
31, (4).

(corresponds to 51, (61), (2) is the outlet of the second-stage processed granules, that is, the small granules, and its arrow indicates the exit direction, as well as the exit direction of the airflow from the crushing chamber, (8) indicates the exhaust direction of the airflow to the suction ventilation device〇And the pore diameter of the first stage screen in the present invention is 1
5 to 25++III, preferably 18 to 22■.

In the figure, the thickness from the entrance (1) is 10 to 80 m, and the width is 50 to 30 m.
0m + length 50” 3001111 Processing material with similar dimensions,
That is, when the polymerization reactant is fed into the crushing passage, the raw material is thrown off in the direction of rotation of the rotary blade due to collision with the rotary blade, and the raw material is blown away by the inner wall of the crushing chamber (5) in the figure, other particles, Furthermore, it moves downstream while repeatedly colliding with the rotating blade (3), and is crushed by the cutting action of the fixed blade (4) and the rotating blade (3) in the figure. In this case, if the coarsely crushed particles have a shape larger than the pore diameter of the screen (6) in the figure, the circulation is repeated until they pass through the pores of the screen. On the other hand, coarse particles with a shape smaller than the pore diameter of the screen are screened by the inertial force received by the collision with the rotating blade (3) and the conveying force of the airflow of the suction draft that passes through the pores of the screen in the same direction as the treated particles. Can easily pass through holes.

However, even coarse particles with a shape smaller than the screen pore diameter
Some particles continue to circulate without encountering the screen hole. Therefore, a certain amount of fine particles are generated due to the repeated cutting action, but the amount of fine particles is extremely small compared to when the above-mentioned suction ventilation is not performed. As the screen hole diameter becomes smaller, the shape of the treated particles becomes smaller, but the cutting action must be repeated several times to achieve a shape that can pass through the screen, which increases the amount of circulation and generates heat due to collisions and cutting actions. The amount will increase. However, in the first stage, the pore size of the screen is relatively large and the processed particles remain in the coarse granule state, so the amount of heat generated is small, and there is also ventilation and cooling in the crushing chamber due to suction ventilation, so the rise in product temperature is slight.

If the pore diameter of the first stage screen is less than f 15 w, the processing capacity will be significantly reduced; if it is more than 25 m, the treated particles will become too coarse and an excessive load will be applied to the second stage. Therefore, in order to provide suitable processing conditions to the second stage and achieve stable processing in the first stage, the pore diameter of the first stage screen should be 18 to 22mm. preferable.

In addition, if suction ventilation is not used, especially in high temperature and high humidity in the summer, the atmospheric conditions that facilitate condensation and the increase in product temperature combine to cause undesirable phenomena such as dew condensation and adhesion of fine particles to the walls of the crushing chamber. Although this occurs, in the first stage, the pore size of the screen is large and the treated particles remain in the form of coarse particles, so problems that do not affect the processing capacity do not occur.

Next, the pore diameter of the second stage screen in the present invention is 7 to 1
It is best to have 5 fins, more preferably 8 to 12 fins. The raw material to be treated in the second stage falls from the first stage in the direction of the arrow (2f in the figure) and is fed to the coarse crushing passage in the second stage, where it is coarsely crushed by the same mechanism as the first stage described above. In order to make the granules into small granules, which are advantageous in terms of drying, it is necessary to make the pore size of the screen smaller than that of the first stage.

If the pore size of the screen is too small and the feed rate of the raw material is not controlled, fine particles may adhere to the wall of the crushing chamber or the fine particles may enter the screen holes. Undesirable phenomena such as clogging begin to appear, and as time passes, the temperature of the product increases significantly, and in many cases it eventually becomes impossible to process.

Particularly during high temperature and high humidity in the summer, dew condensation occurs on the walls of the crushing chamber, and the process becomes impossible in a short period of time. Furthermore, in this case, if suction ventilation is stopped and carried out, a similar phenomenon occurs violently within a very short time, and the process immediately becomes impossible. Moreover, at this time, kneaded dumplings with significantly deteriorated water solubility may be generated in the crushing chamber, which is fatal in terms of quality.

This phenomenon is caused by the reduction of the inertial force exerted by the rotary blade per 1 granular particle as the treated granules become smaller, and the separation force based on the inertial force between the particles, the inner wall of the crushing chamber, and the particle passage surface of the screen hole decreases. On the other hand, in addition to the basic reason that the unit surface area of the particles increases and the adhesion force increases relatively, in addition to this, air currents are generated into the holes of the screen to promote the conveying force of the treated particles, causing roughness. Ventilate the crushing room, suppress the rise in particle temperature, and use suction ventilation to prevent dew condensation.
By incorrectly adopting a screen with a small pore size, the amount of circulation increases abnormally, the frequency of cuts and collisions increases, the amount of heat generated increases, and this accumulates, causing abnormally high product temperatures and condensation. This is due to the overwhelmingly superior adhesive force mentioned above.

In addition, if the hole diameter of the screen is k15 mm or more, even if the coarse crushing effect in the second stage is eliminated, it will only be slight, which is advantageous in terms of drying speed.
It becomes impossible to obtain treated granules with small diameters.

Based on the above, the pore diameter of the second stage screen is 1 to 151.
In order to stably perform large-scale processing of 1 m, the length is preferably 8 to 12 m+, and suction ventilation is required to prevent dew condensation and ensure smooth flow of granules.

Thus, the upper and lower two stages of cutting mills (, A) (
B) performs the coarse crushing action, respectively, in the first stage.

The predetermined coarse crushing process is completed after passing through each screen in the second stage, but during this time, the inside of the coarse crushing chamber (5) is ventilated and cooled due to suction ventilation being carried out through the lower stage screen (6f). The crushing action can proceed smoothly and effectively.

Although the above description is based on the case where the cutting mills are arranged in two stages, upper and lower, it is also possible to increase the number of connected cutting mills if necessary.

In this case, it goes without saying that the hole diameter of the screen should be determined depending on the position of the screen.

In this way, according to the crushing method of the present invention, it is possible to coarsely crush a rubber-like elastic solid polymer reactant starting from a high monomer concentration into small particles in large quantities, and the production cost can be advantageously reduced. At the same time, the hole diameter of the first stage screen is set to 2.
It is larger than that of the second stage, so as not to reduce the processing capacity, and because the air is sucked and ventilated through the screen in the lower stage, and the air flow is in the direction of the flow of the processed granules, there is sufficient ventilation and cooling in the crushing chamber. Therefore, there is no rise in product temperature in the same room, and there is no occurrence of dew condensation on the indoor walls, adhesion of fine particles, adhesion to the screen holes, or clogging, and the roughness of the water-containing high molecular weight water-soluble polymer This is an industrially advantageous method for crushing.

Next, the method of the present invention? This will be explained using an example.

However, the method of the present invention is as described above, and is not limited to the following embodiments as long as it does not depart from the gist thereof.

(Example) At a temperature of 34°C, two commercially available cutting mills with a rotary blade diameter of 320 m+ and a circumferential speed of the same tip of 10 to 20 r/8 were connected in upper and lower stages as shown in Fig. 2, and the upper stage, that is, the first stage cutting A screen hole with a hole diameter of 20 mm is used in the mill, a screen with a hole diameter of 10 m is used in the lower stage, that is, the second stage cutting mill, and a screen hole at the outlet of the treated granules in the second stage is passed through the first stage and second stage f 60 m/ The thickness was 30cm, starting from a seven-layer concentration of 40% by weight while suctioning and ventilating with an air volume of H.
A polymerization reactant with a width of 3QOmm and a length of 300++a+ was treated at a feed rate of 400'9/a/hour for about 1 hour to produce 2~
Treated granules in the form of small particles of 411m+ were obtained.

During this time, stable processing was achieved with no adhesion to the screen, no clogging, and no major changes in the drive motor current. or,
When the screen and the inside of the crushing chamber were inspected after the treatment was completed, almost no clogging or adhesion was observed. The quality of the obtained treated granules, ie, water solubility, was good.

-Method- Using the same cutting mill as above, using a screen with a pore size of 10IlII, and using the same polymerization reactant,
Although processing was carried out at a feed rate of 00'/H, the screen became clogged after approximately 20 minutes, and the coarse crushing had to be discontinued.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of a conventional method using one cutting mill, and FIG. 2 is an explanatory diagram showing an example of the cutting mill arrangement for carrying out the method of the present invention. (A)...1st stage cutting mill. (B)...Second stage cutting mill. (0)...Casing. (1)...Entrance, (2)...Exit. 13+ +31'... Rotating blade, (4) (4)'...
Fixed blade. (51 (5r... coarse crushing chamber, (6) +61'...
·screen. (71 (71'... scattering prevention member, (8)ζ... airflow exhaust direction.

Claims (1)

[Claims] l In a method of coarsely crushing a water-containing high molecular weight water-soluble polymer using a cutting mill, two cutting mills are connected and arranged in two stages, upper and lower, in a continuous passage, and the screen pore diameter of the lower stage is larger than the screen pore diameter of the upper stage cutting mill. The screen hole diameter of the cutting mill is 110N23.
The latter is set to Ma ~ 15I, and at the same time suction ventilation is carried out from the outlet of the treated granules in the lower stage through the lower stage screen, and a flow in the same direction as the flow of the treated granules is generated at each stage of the screen in the passage for coarse crushing. A method for coarsely crushing water-containing high molecular weight water-soluble polymers.