JPS61101536A - Granulation of highly water-absorptive resin powder - Google Patents

Abstract

PURPOSE:To granulate a highly water-absorptive resin powder extremely easily by using an aqueous liquid, which has heretofore been thought impossible due to its high water absorptivity, by uniformly mixing the resin powder with the aqueous liquid in a high-speed rotary paddle mixer and crushing and granulating the product. CONSTITUTION:A highly water-absorptive resin powder (e.g., hydrogenated starch/acrylonitrile graft copolymer) is granulated by uniformly mixing it with an aqueous liquid (e.g., water or a water/water-miscible organic solvent mixture, wherein examples of the organic solvents include lower alcohols, glycerin and acetone) in a high-speed rotary paddle mixer and crushing and granulating the mixture. Said aqueous liquid may contain a deodorant, a plant growth substance or a water-soluble polymer, each soluble in the above aqueous liquid. In order to improve the performance of the highly water-absorptive powder, fine silica particles, carbon black or active carbon may be used jointly with above components.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a method for granulating superabsorbent resin powder.

(Prior Art) In recent years, superabsorbent resins have come to be used in various fields such as sanitary products such as sanitary cotton and disposable diapers, and water retention agents for agriculture, art, and art. However, many of the highly water-absorbing fats that have been used conventionally contain a large amount of fine powder that can pass through a standard 100-mesh sieve (4), so there are the following problems when using them.

(1) Dust is likely to be generated, resulting in deterioration of the working environment and loss of volume.

(2) Poor mixability and dispersibility when mixed with other substances.

(3) It is easy to generate mamako when it comes into contact with liquid.

(4) Since the powder has poor fluidity, it is easy for the formation of bridges and flash phenomena in the perm.

Possible solutions to these problems include removal of fine powder and granulation using a binder. However, the former method is not preferred because it is economically disadvantageous. Further, in the latter method, when an organic solvent-based binder is used, there is a risk of ignition during the drying step of granulation.

Furthermore, if the drying is insufficient, residual organic solvents etc. may cause problems in biological safety. When an aqueous liquid is used as a binder, the problems that occur when using a Ja solvent-based binder do not occur, but due to the property of the granulated material being highly water-absorbent and rapidly absorbing an aqueous liquid. It was difficult to uniformly disperse and mix the aqueous liquid, and large, high-density lumps were likely to occur, making it difficult to obtain homogeneous granules.

(Problems to be Solved by the Invention) 9. In view of the current situation, the inventors of the present invention have conducted extensive studies on the granulation method of super absorbent resin powder, and have found that the granulation method is less than % deuterium.

The amount of aqueous liquid (8) used is 10% of super absorbent resin powder (A).
A ratio range of 1 to 30 parts by weight to 0 parts by weight is preferred. If the amount used is less than 1 part by weight, granulation may be insufficient, and conversely, 30ffi! If the ratio exceeds 1 part i, granules with large particle sizes tend to be produced, which is not preferable.

In the present invention, super absorbent resin powder, powder (A) and aqueous liquid (
In order to uniformly mix B), a high-speed rotating paddle type mixer is used. A high-speed rotating paddle type mixer is a cylindrical container in which a rotor equipped with many paddles rotates at high speed.
Two or more types of powder, or powder and liquid (continuously)
Examples of such materials include 1f1 Turpilizer, Sand Turbo (both manufactured by Hosokawa Micron), etc. In the present invention, super absorbent resin powder (A) and aqueous liquid (B
), the superabsorbent resin powder (A) and the aqueous liquid (B) (continuously ) supply;
The mixture may be discharged (continuously) from the container. Furthermore, the degree of mixing can be freely controlled by adjusting the supply amount, and uniform mixing can be easily achieved even in the combination of powder (A) and aqueous liquid (B), which is difficult to mix uniformly. I can do it.

In the present invention, a granulated product is obtained by uniformly mixing a superabsorbent resin powder (A) and an aqueous liquid (8), and then crushing and granulating the product. I can't do it.

The method of crushing and granulating in the present invention includes a conventional crushing and granulating machine, such as a New Speed Mill (specially manufactured by Kaida Seiko),
Examples include a flash mill [manufactured by Fuji Powderoo] and a speed mill [manufactured by Showa Engineering ■]. The crushing and granulation may be carried out immediately after the superabsorbent resin powder (A) and the aqueous liquid (B) are uniformly mixed, or may be carried out after being left for a certain period of time.

In the present invention, when the superabsorbent resin powder (A) and the aqueous liquid (8) are uniformly mixed using a high-speed rotating paddle type mixer, the fluidity of the powder (A) is improved and the high-speed rotating paddle type mixer is used. Particulate silica, which is effective in fully enhancing the mixing effect of the machine, and effective in improving the light resistance of super absorbent resins, and also has a deodorizing effect.
- Bomb black and/or activated carbon may be used in combination.

Therefore, the present invention is characterized in that the super absorbent resin powder ('A), the water stick liquid (B), and the particulate silica are uniformly mixed using a high-speed rotating paddle mixer, and then crushed and granulated. A granulation method of super absorbent resin powder, super absorbent resin powder (A), aqueous liquid (B), carbon black and/or
Alternatively, the present invention also provides a method for granulating super-absorbent resin powder, which is characterized in that activated carbon is uniformly mixed using a high-speed rotating paddle mixer and then crushed and granulated.

Particulate silica is 211 with an average particle size of 50μ or less.
The main component is silicon oxide, and examples include "Aerosil 200" manufactured by Nippon Aerosil ■ and "Carplex #80" manufactured by Shionogi & Co. TM.

The amount of fine particulate silica used is 1: super absorbent resin powder (A)
The ratio is more than 20 parts by weight to 00 parts by weight. Even if the amount exceeds 20 parts by weight, the effect commensurate with the added layer will not be significantly reduced, and the superabsorbency of the granulated product may be inhibited or, in some cases, the granulation may become difficult. As carbon black and/or activated carbon, commercially available powders can be used.

The amount of carbon black and/or activated carbon used is more than 0 and 5 parts by weight per 100 parts by weight of super absorbent resin powder (A).
The ratio is 0 parts by weight or less.

If the amount exceeds 50 parts by weight, it is not preferable because it impairs the high water absorbency of the resulting granules.

In order to achieve uniform mixing when granulating fine particulate silica, carbon black, and activated carbon in combination, for example, fine particulate silica, carbon black, and activated carbon can be combined with super absorbent resin powder (A) or aqueous liquid (B). Similarly, it is also possible to mix by immediately feeding it into the high-speed rotating paddle type mixer, or by mixing various types of fine particulate silica, powder, pump rack, or activated carbon.
The superabsorbent resin powder (A) may be premixed with the superabsorbent resin powder (A) by mixing lines, and the obtained premix and aqueous liquid (B) may be supplied to the high-speed rotation paddle type mixer for uniform mixing.

Even when granulating using fine particulate silica, carbon black, or activated carbon, the same aqueous liquid (B ) may be employed, and a water-soluble deodorant, a plant growth aid, a water-soluble polymer, etc. may be dissolved in the aqueous liquid (B).

In addition, the preferred amount of the aqueous liquid (B) used is 11,100 weight of the total of super absorbent resin powder (A) and fine particulate silica] or the total of super absorbent resin powder (A) and carbon black and/or activated carbon. The ratio is 1 to 30 parts per part.

(Effects of the Invention) According to the method of the present invention, granulation of highly water-absorbent resin powder with an aqueous liquid, which was conventionally thought to be impossible due to its high water-absorbency, can be carried out very easily and suitably. Moreover, in the general wet granulation method, a drying step is always required after granulating with a binder, before uniformly mixing the binder and sizing, or after sizing. The granulation method of the present invention uses a relatively aqueous liquid as a binder, and since the superabsorbent resin has the property of absorbing water quickly, there is no need for a drying process, which is extremely important for industrial use. It is advantageous for The superabsorbent resin powder granules obtained by the method of the present defense using the aqueous liquid (B) contain less fine powder and have a uniform particle size distribution, and are less likely to cause dirt on roads and deterioration of the working environment due to the generation of dust. It has good mixability, dispersibility, and fluidity, and there is no need to worry about bridge formation in the hopper or flash yl phenomenon, and it is difficult to generate mako, so it can be used for sanitary products such as menstrual cotton and disposable diapers, and FM. It can be used in a wide range of fields, including as a water retention agent and desiccant for horticulture.

Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited only to these Examples. In the examples, unless otherwise specified, % means % by weight, and parts mean parts by weight.

Example 1 Sodium acrylate 74.95 mol%, acrylic acid 2
43% of acrylate monomers consisting of 5 mol% and 0.05 mol% trimethylolpropane triacrylate
4,000 parts of the aqueous solution was polymerized by standing at 55-80°C in a nitrogen atmosphere using 0.6 m of ammonium persulfate and 0.2 parts of sodium bisulfite to obtain a gel-like water content polymer. This gel-like hydrous polymer was dried in a hot air dryer at 180° C., then ground in a hammer-type grinder, and sieved through a 20-mesh wire gauze to obtain a 20-mesh material (powder A).

Using a Sand Turbo (manufactured by Hosokawa Micron ■), water was added dropwise to Powder A at a ratio of 5 parts of water to 100 parts of Powder A to uniformly mix the Powder A and water. After mixing, the mixture was crushed and granulated using a flash mill (manufactured by Fuji Baudaru) to obtain a granulated product (1).

The particle size distribution of the obtained powder A and granules (1) was measured using a Shinra sieve. The results are shown in Table 1. In the granulated product (1), the amount of fine powder was significantly reduced, and no dust was observed.

Comparative Example 1 Powder A obtained in Example 1 was granulated in the same manner as in Example 1 except that a ribbon blender was used for mixing with water, and a comparative granule ( 1) was obtained. Comparative granules (
In 1), many clusters of 5'JllllI in particle size were observed.

The particle size distribution of the obtained comparative granules (1) was measured in the same manner as in Example 1. The results are shown in Table 1.

Comparative granules (1) contained a lot of fine powder, and dust was generated when the powder was transferred to moss.

Example 2 50 parts of corn starch, 200 parts of water, and 1000 parts of methanol were charged into a reactor equipped with a stirring rod, a nitrogen blowing tube, and a thermometer, stirred at 50°C for 1 hour under a nitrogen stream, and then cooled to 30°C. 25 parts of acrylic acid, 75 parts of sodium acrylate, 0.5 part of methylenebisacrylamide, 0.1 part of ammonium persulfate as a polymerization catalyst and 0.1 part of fli! as a promoter. When 1111 sodium hydride was added and the mixture was reacted at 60° C. for 4 hours, a white suspension was obtained.

The powder obtained by filtering this white suspension was washed with a water-methanol mixed solution (water:methanol weight ratio: 2:10), dried under reduced pressure at 60°C for 3 hours, and then ground. The mixture was sieved through a 48-mesh wire mesh to obtain a material passing through the 48-mesh mesh (powder B).

Turbi riser for powder B [manufactured by Hosokawa Micron TM]
m of polyacrylic acid (molecular a about 3000) using
An aqueous solution containing 2% Maro was mixed at a ratio of 10 parts to 100 parts of powder B. Thereafter, the mixture was crushed and granulated in the same manner as in Example 1 to obtain a granulated product (2).

The particle size distribution of the obtained powder B and granules (2) is as shown in Example 1.
Measured in the same manner. The results are shown in Table 1. Granules (
In case 2), the amount of fine powder was significantly reduced and no dust was observed.

Example 3 99 parts of powder A obtained in Example 1 and fine particulate silica (
Nippon Aerosil (1M'Ar Aerosil 200J) 1
Using a sand turbo [manufactured by Hosokawa Micron ■],
10 parts of water was added dropwise to uniformly mix powder A, particulate silica, and water. The resulting mixture was crushed and granulated in the same manner as in Example 1 to obtain a granulated product (3).

The particle size distribution of the obtained granules (3) was measured in the same manner as in Example 1. The results are shown in Table 1. In the granulated product (3), the amount of fine powder was significantly reduced, and no dust was observed.

Example 4 99 parts of powder A obtained in Example 1 and carbon black (Mitsubishi Carbon Black #600J manufactured by Mitsubishi Chemical Corporation)
) Using a Sand Turbo (manufactured by Hosokawa Micron ■), 10 parts of water was dropped to uniformly mix the powder A1 carbon black and water. The resulting mixture was crushed and granulated in the same manner as in Example 1 to obtain granules (4).

The particle size distribution of the obtained granules (4) was measured in the same manner as in Example 1. The results are shown in Table 1. In the granulated product (4), the amount of fine powder was significantly reduced, and no dust was observed.

Example 5 Powder A98. obtained by actual fullfill. Using a sand turbo [manufactured by Hosokawa Micron ■], 10 parts of water was added dropwise to 2 parts of powdered activated carbon (Shirasagi M manufactured by Shikinichi Yakuhin Kogyo Co., Ltd. (Kiki)) to dissolve powder A, powdered activated carbon, and water. The resulting mixture was crushed and granulated in the same manner as in Example 1 to obtain a granulated product (5).

The particle size distribution of the obtained granules (5) was measured in the same manner as in Example 1. The results are shown in Table 1. In the granulated product (5), the amount of fine powder was significantly reduced, and no dust was observed.

Example 6 15% leaf extract of camellia plant instead of water in Example 1
Powder A was granulated in the same manner as in Example 1, except that the same amount of the aqueous solution (trade name Nl-Fresca 5800MO1 manufactured by Shiraimatsu Shinyaku ■) was used to obtain a granulated product (6).

The particle size distribution of the obtained granules (6) was measured in the same manner as in Example 1. The results are shown in Table 1. Granules (6) did not generate dust and had good workability.

Example 7 Powder A was granulated in the same manner as in Example 1, except that 10 parts of 15% hydrogen peroxide solution was used instead of water in Example 1.
Granules (7) were obtained.

The particle size distribution of the obtained granules (1) was measured in the same manner as in Example 1. The results are shown in Table 1. Granules (7) did not generate dust and had good workability.

Example 8 Powder A was granulated in the same manner as in Example 1, except that 10 parts of a 20% urea aqueous solution was used instead of water in Example 1, to obtain a granulated product (8).

The particle size distribution of the obtained granules (8) was measured in the same manner as in Example 1. The results are shown in Table 1. Granules (8) did not generate dust and had good workability.

Example 9 Powder A, B and granules (1) obtained in Examples 1 to 5
- (5) and the comparative granules (1) obtained in Comparative Example 1 were used to evaluate their mamako production and absorption capacity using the following methods. The results are shown in Table 2.

Mamako production was evaluated by dropping a small amount of the sample onto paper moistened with water and observing the appearance.

In addition, sample 0.29 was placed in a non-woven tea bag bag (40
m The absorption capacity of the sample was calculated.

Weight of K class ((J) Table 1 (Note) 20 mesh weight % of the weight of items that have not passed through the 20 mesh wire mesh 20 bath ~ 48 weight = Weight that has passed through the 20 mesh wire mesh and has not passed through the 48 mesh wire mesh %48 bus~1
00 on: 48 mesh wire mesh passed through, 100 mesh wire wire not passed through mm% 100 bath ~ 200 on: 1
00 mesh wire mesh passed, 200 mesh wire mesh not passed'
Weight of iA object 1? 6200 mesh bath: 200 mesh Important percentage of objects passing through wire mesh Table 2 ×: Mamako can be formed

Claims (20)

[Claims] (1) Granulation of super absorbent resin powder, characterized in that super absorbent resin powder (A) and aqueous liquid (B) are mixed uniformly using a high-speed rotating paddle mixer, and then crushed and granulated. Law. (2) For 100 parts by weight of super absorbent resin powder (A),
A method for granulating super absorbent resin powder according to claim (1), wherein the aqueous liquid (B) is used in a proportion of 1 to 30 parts by weight. (3) Granulation of the super absorbent resin powder according to claim (1), wherein the particle size of the super absorbent resin powder (A) is 50% by weight or less that passes through a 200 mesh standard sieve. Law. (4) The method for granulating super absorbent resin powder according to claim (1), wherein the aqueous liquid (B) has a water-soluble deodorant dissolved therein. (5) The method for granulating super-absorbent resin powder according to claim (1), wherein the aqueous liquid (B) has a plant growth aid dissolved therein. (6) The method for granulating super absorbent resin powder according to claim (1), wherein the aqueous liquid (B) has a water-soluble polymer dissolved therein. (7) A super absorbent resin powder characterized by uniformly mixing super absorbent resin powder (A), aqueous liquid (B), and particulate silica using a high-speed rotating paddle mixer, and then crushing and granulating the mixture. Granulation method. (8) Claim No. 7, in which the aqueous liquid (B) is used in a ratio of 1 to 30 parts by weight to 100 parts by weight of the total amount of the super absorbent resin powder (A) and the particulate silica. Granulation method of super absorbent resin powder described in Section 1. (9) Granulation of the super absorbent resin powder according to claim (7), wherein the particle size of the super absorbent resin powder (A) is 50% by weight or less that passes through a 200 mesh standard sieve. Law. (10) The super absorbent resin powder according to claim (7), wherein the ratio of fine particulate silica to 100 parts by weight of the super absorbent resin powder (A) is more than 0 and 20 parts by weight or less. Granulation method. (11) The method for granulating a super absorbent resin powder according to claim (7), wherein the aqueous liquid (8) has a water-soluble deodorant dissolved therein. (12) The method for granulating super absorbent resin powder according to claim (7), wherein the aqueous liquid (B) has a plant growth aid dissolved therein. (13) The method for granulating a super absorbent resin powder according to claim (7), wherein the aqueous liquid (B) has a water-soluble polymer dissolved therein. (14) Super absorbent resin powder (A), aqueous liquid (B), carbon black and/or activated carbon are uniformly mixed using a high-speed rotating paddle mixer, and then crushed and granulated. Granulation method of synthetic resin powder. (15) Claim 1 in which the aqueous liquid (B) is used in a ratio of 1 to 30 parts by weight with respect to 100 parts by weight of the total amount of the super absorbent resin powder (A) and carbon black and/or activated carbon. (14) A method for granulating super absorbent resin powder as described in section (14). (16) Granulation of the super absorbent resin powder according to claim (14), wherein the particle size of the super absorbent resin powder (A) is 50% by weight or less that passes through a 200 mesh standard sieve. Law. (17) Carbon black and/or activated carbon exceeds 0 and 50 parts by weight per 100 parts by weight of super absorbent resin powder (A)
A method for granulating super absorbent resin powder according to claim (14), wherein the ratio is less than or equal to parts by weight. (18) The method for granulating super absorbent resin powder according to claim (14), wherein the aqueous liquid (B) has a water-soluble deodorant dissolved therein. (19) The method for granulating super-absorbent resin powder according to claim (14), wherein the aqueous liquid (B) dissolves a plant growth aid. (20) The method for granulating super absorbent resin powder according to claim (14), wherein the aqueous liquid (B) has a water-soluble polymer dissolved therein.