JP2000189794A - Production of water absorbing material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a water absorbing material having high quality and performance with high productivity by depositing fine powder of a water absorbing resin on a thin layer, supplying water to the fine powder layer and drying after pressing the water absorbed fine powder layer, to which water is supplied. SOLUTION: The fine powder 20 of the water absorbing resin housed in a hopper 24 is scattered by falling down on the flat supporting plate 10. The fine powder 20 is deposited on the whole surface of the supporting plate 10 with a fixed thickness to form the fine powder layer 22. Next, the water 30 is sprayed from a spray nozzle 32 disposed above the fine powder layer 22. The water absorbed fine powder layer 22 is expanded and integrated by joining the adjacent particles to each other. Further, the fine powder layer 22 is pressed by making a pressing plate 40 descend from the upper side of the fine powder layer 22. The gap present among the particles of the fine powder layer 22 is decreased and the particles are stuck to each other by the pressure and strongly joined. The action to remove excess water contained in the fine powder layer 22 is also exhibited. The fine powder layer 22 finished in the pressurizing treatment, that is, a water absorbing sheet 25 is dried at need.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a water-absorbing material, and more particularly to a method for producing a practical water-absorbing material using fine powder of a polymer water-absorbing material.

[0002]

2. Description of the Related Art Highly water-absorbing materials using polyacrylic acid resins are widely used for sanitary articles such as disposable diapers and water-absorbing materials for agriculture and horticulture. Such water-absorbing materials are usually
Often manufactured and supplied in powder form. The powdery water-absorbing material has good absorbability for liquids such as water, and is easy to handle such as being loaded on various products and compounded.

[0003] The performance of a water-absorbing material is greatly affected by differences in particle size in addition to the properties of the material. If the particle size is too large, it will be difficult to handle such as carrying on a product, and the liquid absorption performance will also be poor. If the particle size is too small, it is difficult to handle due to the generation of dust, and when it comes into contact with a liquid, so-called mamako is formed, resulting in poor water absorption. There is an appropriate particle size range as a practical water absorbing material. In particular, the finely powdered water-absorbing material is considered to have a large problem of the above-described dust generation and generation of mamako during use, and is poor in practicality.

Therefore, conventionally, the produced powdery water-absorbing material is classified and fine powder having a particle size smaller than a predetermined value is removed, and only particles within a certain particle size range are used as a water-absorbing material product. The removed fines are discarded. In recent years, from the viewpoint of resource protection, it has been considered to collect and recycle used water absorbing materials. Fine powder similar to that described above is also generated in the step of regenerating the used water absorbing material.

As a technique for reusing these fine powders, there has been proposed a method of granulating a fine powdery water-absorbing material and regenerating it into a water-absorbing material having a certain or more particle size.
No. 08, JP-A-10-113551, JP-A-10-204184 and the like. The granulated water-absorbing material has complex irregularities on the surface or has fine gaps inside, so that water absorption may be performed faster and more efficiently than normal particles In addition, there is a possibility that a water-absorbing material excellent in water-absorbing performance can be obtained.

In the step of granulating the fine powdery water-absorbing material, by supplying an appropriate amount of water to the water-absorbing material, the fine powders are easily aggregated, and the physical and chemical bonds between the fine powders are generated. And it is advantageous in that a granulated product having excellent integrity can be obtained. When the granulated water-absorbing material is used, there is also an advantage that individual particles hardly fall apart in a water-absorbing process. It has also been proposed to mix a crosslinking agent or a bonding agent for the water-absorbing material when supplying water, and it is said that the above-mentioned advantages can be further enhanced.

[0007]

In the aforementioned water-absorbing material granulating technique, when a liquid such as water is supplied to a finely powdered water-absorbing material, the above-mentioned mamako phenomenon occurs, and the supplied liquid is entirely absorbed by the water-absorbing material. However, there has been a problem that it is difficult to uniformly supply the water-absorbent material, and that the granulation is not performed well and the performance of the obtained water-absorbing material does not improve as expected.

Therefore, while stirring the fine powdery water absorbing material,
It has been proposed that the liquid be supplied there to supply the liquid uniformly to the entire water-absorbing material, but the effect was still insufficient. This is because, even when the fine powdery water-absorbing material is being stirred, if a mamako is generated in the portion to which the liquid is supplied, the lump of the mamako remains without being easily broken even by the agitation. In addition, the water-absorbing material supplied with the liquid and having increased viscosity is difficult to stir, and a sufficient stirring effect cannot be achieved.

If a large excess of liquid is supplied with respect to the amount of the water absorbing material, the absorption of the liquid into the water absorbing material is improved to some extent.
Because the granulated water absorbing material contains a large amount of water,
The drying process for removing unnecessary moisture requires a long time and large energy. Also, no matter how much liquid is present, it is difficult to prevent the occurrence of the aforementioned momoko, and it is difficult to eliminate the momako once generated.

An object of the present invention is to make it possible to produce a water-absorbing material with high productivity and high quality performance even when a finely powdered water-absorbing material is used.

[0011]

A method of manufacturing a water-absorbing material according to the present invention is a method of manufacturing a water-absorbing material using fine powder of a water-absorbing resin. (a), a step (b) of supplying water to the fine powder layer, a step (c) of pressing the water-absorbing fine powder layer supplied with water, and a step (d) of drying the pressurized water-absorbing fine powder layer including. [Fine powder of water-absorbing resin] As the water-absorbing resin as a raw material, the same water-absorbing resin as that of a normal water-absorbing material is used. In particular,
Examples include a polyacrylic acid-based resin, a starch-acrylic acid graft copolymer, an isobutylene-maleic anhydride copolymer, and a crosslinked polyalkylene oxide.

These water-absorbing resins may be newly produced by polymerizing from a monomer, or may be fine powder as unnecessary substances generated in the process of producing a water-absorbing material having a relatively large particle size. Or a fine powder generated when the used water-absorbing material is regenerated. After pulverizing the water-absorbent resin into powder, the powder is classified with a normal sieve device, whereby a fine powder having a predetermined particle size can be obtained. As the water-absorbing resin classified by a sieve (sieve), a resin subjected to surface cross-linking described later or a water-absorbent resin before surface cross-linking can be used.

The particle size of the fine powder can be changed depending on the purpose of use and required performance of the water absorbing material. Usually, a material that passes through a 212 μm sieve is used. Average particle size 50-150 μm
Is preferred. The shape of the fine powder varies depending on the manufacturing method and the history after manufacturing, for example, in addition to a general spherical shape, a shape having irregularities or distortion in a part of the spherical shape, an irregular crushed shape or a scale-like shape, a fibrous shape And others. [Deposition Step (a)] By supplying the fine powder using a spray nozzle or the like on a support surface such as a flat table capable of supporting the fine powder, the fine powder can be deposited in a layered manner. The fine powder is preferably kept in a dry state.

As the support surface, a smooth base, plate, sheet, film or the like made of metal, synthetic resin, ceramic or the like is used. If the fine powder does not fall off, it may be made of a mesh-like material or a porous material. The thickness of the fine powder layer is such that when water is supplied to the fine powder layer, the moisture quickly and uniformly reaches and is absorbed by the fine powder particles constituting the fine powder layer, and the absorbed fine powder particles are joined together to be integrated. Set to be easy. Specifically, the thickness is set to a basis weight of 10 to 2000 g / m ^{2 although} it varies depending on conditions such as the particle size of the fine powder and the purpose of use of the water absorbing material. Preferably a basis weight of 100 to 1000 g / m ^2. [Water supply step (b)] An amount of water necessary for bonding and integrating the fine particles constituting the fine powder layer is supplied. Specifically, 1 to 500 parts by weight, preferably 2 to 100 parts by weight, more preferably 5 to 70 parts by weight is supplied to 100 parts by weight of the fine powder.

Water can be supplied by spraying water from above the fine powder layer using a shower nozzle, a curtain nozzle or the like. Water can also be supplied in mist. Moisture can also be supplied to the fine powder layer by setting the entire atmosphere in which the fine powder layer is disposed to a high humidity state in which moisture is filled.
Drugs and components other than water may be mixed in the supplied water. For example, a cross-linking agent that causes a cross-linking reaction to the resin constituting the fine powder can be blended. A tacky or adhesive material for joining the fine powders can be blended. Specifically, a material used as a binder in a known granulation method is used.

The fine powder layer to which water has been supplied, that is, the water-absorbing fine powder layer, is in a sheet state in which the fine powders are combined and integrated. In the water-absorbing fine-powder layer to which the water is supplied, the water is evenly distributed throughout, or the bonding of the fine powders by the water is sufficiently performed, and the function of the crosslinking agent contained in the water is sufficiently expressed. The water-absorbing fine powder layer before sending to the next pressurizing step can be held for a certain period of time. [Pressing step (c)] The fine powder layer to which water has been supplied, that is, the water-absorbing fine powder layer, is pressed in the plane direction. Specifically, pressure can be applied by passing the water-absorbing fine powder layer between the opposing rolls. The roll can be rolled and pressed on the water-absorbing fine powder layer placed on a flat table. Various presses can be used.

The pressure applied to the water-absorbing fine powder layer varies depending on the material of the fine powder and the purpose of use of the water-absorbing material.
/ cm ² pressure can be applied. If the pressure is too low, the object of the present invention cannot be achieved.If the pressure is too high, the fine powder may be damaged or broken, or the capillary gap between the particles may be closed, resulting in a poor water absorption rate. And adversely affect the performance of the water-absorbing material.

In the pressurized water-absorbing fine powder layer, the gap between the fine powders is reduced, the bonding between the fine powders is strengthened, and the integrity is improved. Pressurization can also remove excess water contained in the water-absorbing fine powder layer. [Drying step (d)] The pressurized water-absorbing fine powder layer can be used as it is as a water-absorbing material, or can be commercialized through a shredding step (e). A drying process is performed for adjustment. In particular, when the pulverizing step (f) is performed, a drying step is required.

For the specific drying treatment, the same apparatus and processing conditions as those used in the ordinary technique for producing a water-absorbing material can be employed. For example, there are means such as heating with a heater or hot air, and vacuum drying. Depending on the drying process, the water content of the fine powder layer is reduced to 0.1 to 2
It can be reduced to 0% by weight. The dried water-absorbing fine powder layer, that is, the dried fine powder layer, can be used as it is as a water-absorbing material. Grinding process (f) and shredding process (e)
And can be commercialized. [Shredding step (e)] The water-absorbing fine powder layer is shredded into a shape required for a water-absorbing material product or a size that facilitates the pulverizing step (f).

For shredding, ordinary cutting means and cutting means such as scissors and cutters are used. Although it differs depending on the shredding means, the shredding step is easier to perform in the state of the water-absorbing fine powder layer, and it may be difficult to shred the dried fine powder layer after the drying step (d). The size of the finely chopped fine powder layer, that is, the size and shape of the finely chopped fine powder layer depends on conditions such as the purpose of use, required performance, and the type of shredding means. For example, fine strips, polygons, irregular shapes, and the like can be obtained.

For the finely divided pulverized layers having various shapes,
When the maximum dimension of the passing diameter of each finely divided fine powder layer is defined as the maximum length of the finely divided fine powder layer, the maximum length is 0.5 to 100 mm, preferably 1 to 50 mm in the chopping step. Can be shredded. [Pulverizing Step (f)] Various pulverizing apparatuses and pulverizing methods employed in the ordinary water absorbing material manufacturing technology can be applied.

The pulverizing step is difficult to perform with the water-absorbing fine powder layer containing a large amount of water, and it is preferable to use the dry fine powder layer after the drying step (d). Depending on the characteristics of the pulverizing device, the fine powder layer supplied to the pulverizing step may be in the form of a large sheet or may be cut into a certain size. The finely chopped fine layer obtained in the shredding step (e) is also used.

In the pulverization step, the particles may be pulverized to a particle size suitable for the purpose of use as the water-absorbing material and the required performance.
The dried fine powder layer can be pulverized to an average particle size of 200 to 800 μm. When fine powder is generated during the grinding process,
It can be classified and fed again to step (c). [Water-absorbing material] As described above, the water-absorbing material can be used in any form of shredded or pulverized material. Both non-dried and dry states are possible.

The water-absorbing material is used for the same purpose as a normal water-absorbing resin. For example, there are sanitary articles such as disposable diapers, agricultural and horticultural applications such as water retention materials for plant cultivation, civil engineering applications, and medical applications. The water-absorbing material obtained in the present invention can be used by being mixed with another water-absorbing material. Further processing steps can be added to the water absorbing material to obtain a water absorbing material product.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Overall Process] The embodiment shown in FIG. 1 schematically shows the method of the present invention. As shown in FIG. 1A, a flat support 10 made of acrylic resin or the like is used.
The fine powder 20 stored in the hopper 24 is dropped and sprayed on the hopper. By moving the hopper 24 and the support base 10 relatively horizontally, the fine powder 2 having a constant thickness is formed on the entire support base 10.
0 is deposited, and the fine powder layer 22 is formed.

As shown in FIG. 1 (B), water 30 is sprayed from a spray nozzle 32 disposed above the fine powder layer 22. By moving the spray nozzle 32 and the support 10 relatively horizontally, moisture is supplied to the entire fine powder layer 22. Fig. 1 (C)
As shown in (2), the water-absorbed fine powder layer 22 expands and adjacent particles are joined together to be integrated.

As shown in FIG. 1 (D), the pressure plate 40 is lowered from above the fine powder layer 22 placed on the support base 10 to apply pressure. Due to the pressurization, the gap existing between the particles of the fine powder layer 22 is reduced, and the particles are pressed against each other and strongly bonded. There is also an action of dropping excess water contained in the fine powder layer 22. As shown in FIG. 1 (E), the fine powder layer 22, that is, the water-absorbing material sheet 25, which has been subjected to the pressure treatment, is subjected to a drying treatment as necessary, and then used as it is for various purposes. be able to. [Pulverizing Step] In the embodiment shown in FIG. 2, the water-absorbing material sheet 25 after the drying process is supplied to the crusher 50. Crusher 50
From this, water-absorbing material particles 26 pulverized to a desired particle size are obtained. The water absorbing material particles 26 obtained by the pulverization can be used as a water absorbing material product as it is. In addition, classification can be performed after pulverization to obtain water-absorbing material particles having a desired particle size distribution. [Shredding Step] In the embodiment shown in FIG. 3, the water-absorbing material sheet 25 that is not subjected to the drying process is supplied to the cutting machine 54 to obtain the shredded water-absorbing material 28 having fine dimensions. Obtained shredded water-absorbing material 28
Can be used as it is as a water-absorbing material product, or the shredded water-absorbing material 28 can be further subjected to a drying treatment before being made into a water-absorbing material product. Further, the shredded water-absorbing material 28 is dried and sent to the pulverizer 50 in FIG.
It is also possible to improve the workability of the pulverization. [Continuous Processing Line] In the embodiment shown in FIG. 4, the method of the present invention is configured as a continuous processing line. The individual processing steps are basically the same as in the above-described embodiments.

The fine powder 20 is supplied from the hopper 24 onto the continuously running conveyor 12. On the conveyor 12, a fine powder layer 22 having a certain thickness is formed. Hopper 2
By controlling the supply speed of the fine powder 20 from 4 and the traveling speed of the conveyor 12, the thickness of the fine powder layer 22 can be controlled. Water 30 is sprayed on the fine powder layer 22 from the spray nozzle 32 arranged above in the middle of the traveling route of the conveyor 12. The fine powder 20 constituting the fine powder layer 22 absorbs moisture, expands, and joins and integrates with each other. Such an action proceeds while traveling on the conveyor 12 for a certain distance and time.

A pressure roller device 42 is disposed in front of the conveyor 12 in the downstream direction, and the fine powder layer 22 discharged from the conveyor 12 is pressed from above and below by the pressure roller device 42. The fine powder layer 22 discharged from the pressure roller device 42, that is, the water-absorbing material sheet 25 can be collected as it is to obtain a water-absorbing material product.

In the figure, the sheet 25 of water absorbent material is cut by a cutting device 54.
And is chopped into fixed dimensions. The chopped water absorbing material 28 can be directly used as a water absorbing material product. In the figure, for the sake of simplicity, the shredded water-absorbing material 28 is directly supplied to the pulverizer 50. However, practically, after the shredded water-absorbing material 28 is sent to a drying device and dried. In the crusher 50
Preferably.

The collection container 5 arranged below the crusher 50
In No. 2, water-absorbing material particles 26 having a desired particle size are obtained. In the continuous processing line as described above, the processes from the fine powder 20 to the production of the desired water-absorbing material particles 26 can be continuously and automatically performed, and the productivity can be improved. [Surface Crosslinking] The water-absorbent resin particles 26 obtained by the above method can be subjected to surface crosslinking for crosslinking the vicinity of the surface of the resin particles 26.

As the surface cross-linking agent, a functional group capable of reacting with a functional group such as a carboxyl group of the resin particles 26 is used.
More than one surface cross-linking agent can be used. When the water-absorbent resin particles 26 are obtained from a 212-μm sieve that is generated when pulverized after drying in the production method, the resin particles 26 are subjected to a surface cross-linking treatment, and further subjected to a surface cross-linking treatment separately. Can be used by mixing with a 212 μm sieve. In addition, the water absorbent resin particles 2
After mixing 6 with the 212 μm sieve obtained by classification, surface cross-linking treatment can also be performed. When the surface cross-linking treatment is performed with fine powder removed from the water-absorbent resin particles, it is easy to uniformly mix the surface cross-linking agent with the water-absorbent resin particles, and the water-absorbent resin particles having excellent absorption capacity under pressure are obtained. Can be

As the surface cross-linking agent that can be used in the above treatment, the same material as the surface cross-linking agent for ordinary water-absorbent resin particles is used. Specifically, ethylene glycol,
Propylene glycol, 1,3-butanediol, 1,
4-butanediol, glycerin, pentaerythritol, ethylene carbonate, propylene carbonate,
(Poly) ethylene glycol diglycidyl ether, polyaluminum chloride, aluminum sulfate, polyamidepolyamine epichlorohydrin condensate and the like.

The amount of the surface cross-linking agent is not particularly limited, but is generally in the range of 0.01 to 10 parts by weight per 100 parts by weight of the water-absorbing resin particles. If the amount used is excessive or too small, it becomes difficult to obtain water-absorbent resin particles having a high absorption capacity under pressure. The surface crosslinking treatment is preferably performed in the presence of water. By performing the surface crosslinking treatment in the presence of water, the degree of the surface crosslinking can be appropriately controlled. The amount of water used per 100 parts by weight of the water absorbent resin is preferably in the range of 0.01 to 20 parts by weight.

The treatment temperature of the surface crosslinking treatment can be appropriately set depending on conditions such as the kind and amount of the surface crosslinking agent, but generally, a temperature in a range from room temperature to 220 ° C. can be adopted.

[0036]

EXAMPLE A description will be given of the result of specifically manufacturing a package of the present invention and evaluating its performance. In addition, the part which shows the amount and compounding ratio of each material means a weight part. [Production Example 1 of Water Absorbent Resin Particles] A 75% aqueous solution of neutralized sodium acrylate (monomer concentration: 38% by weight) containing 0.04 mol% of trimethylolpropane triacrylate (based on sodium acrylate monomer) was prepared. The dissolved oxygen was removed by blowing. In this monomer aqueous solution,
Sodium persulfate and ascorbic acid were added and polymerized. The hydrogel obtained by the polymerization was dried and pulverized. The pulverized material was classified into a sieve (water-absorbent resin particles A) remaining on a 150-μm sieve after passing through a 850 μm sieve and a sieve-passed material (water-absorbent resin particles B) passing through a 150 μm sieve. The absorption capacity of the water-absorbent resin particles A was 43 g / g as measured by a conventional method. The Example 1-6] Production Example 1 resulting water-absorbing resin particles B, was sprayed at a basis weight 600 g / m ² on the acrylic plate.
A deposited layer of the water-absorbent resin particles B was formed. The deposited layer of water-absorbent resin particles B placed on the acrylic plate was
Moisture was imparted by leaving the sample in a constant temperature and humidity apparatus of H for a predetermined time.

A predetermined pressure was applied to the particle deposition layer on the acrylic plate taken out of the thermo-hygrostat to apply pressure. The pressurized particle deposition layer is dried at 150 ° C.
Classification was performed using a sieve of 0 μm and a sieve of 150 μm, and a sieve that passed through a sieve of 850 μm and remained on a sieve of 150 μm was obtained. The physical properties of the obtained water-absorbing material particles were measured, and the results are shown in Table 1.

Water supply amount: The weight increase after the water supply treatment with respect to the weight of the water-absorbent resin particles is represented by% by weight. Recovery rate: expressed as 850-150 μm particle amount / (850-150 μm particle amount + 150 μm passing particle amount) × 100%.

Absorption capacity: After immersion in physiological saline for 60 minutes, excess saline was removed with a centrifuge. The weight before and after the treatment was measured. Calculated as absorption capacity = (weight after measurement−weight before measurement) / weight before measurement.

[0040]

[Table 1] ─────────────────────────── Pressure Water supply rate Recovery rate Absorption capacity kg / cm ² %% ％ ─────────────────────── Example 1 23 35 70 42 Example 2 23 50 80 42 Example 3 23 100 80 41 Example 4 12 35 55 42 Example 5 12 50 70 42 Example 6 12 100 80 42 実 施 [Example 7] The above example In 1, the pressurized particle deposition layer, that is, the water-absorbing material sheet was cut into a maximum length of 1 mm or less using a cutter, and then dried at 150 ° C. The fine powder having a particle size of 150 μm or less contained in the dried product was 1%. Comparative Example 1 Water was added to 100 parts of water-absorbent resin particles B while stirring the water-absorbent resin particles B at a high speed with a stirring blade type stirring device. Hydrate adhered and it became difficult to continue stirring. [Comparative Example 2] 100 parts of the water-absorbent resin particles B were put in a ball-shaped container, and 100 parts of water was added and mixed. As a result, a water-containing gel partially having mamaco was obtained. An attempt was made to stretch the hydrated gel into a sheet and to form it, but the viscosity of the gel was so high that molding was difficult. Example 8 20 parts of the water-absorbing material particles obtained in Example 2,
80 parts of the water-absorbent resin particles A obtained in Production Example 1 were mixed. To 100 parts of the mixture, 0.03 part of ethylene glycol diglycidyl ether, 0.5 part of propylene glycol
Parts, 3 parts of isopropyl alcohol and 1 part of water were mixed and heated to obtain water-absorbent resin particles C.

The resulting water-absorbent resin particles C had an absorption capacity of 3
It was 2 g / g. The absorption capacity of physiological saline under a pressure of 0.7 psi was 22 times. Comparative Example 3 The water-absorbent resin obtained in Production Example 1 was 850 μm
m to obtain water-absorbent resin particles D. Water absorbent resin D
Among them, 18% of fine particles passing through a 150 μm sieve were present.

Water-absorbing resin particles E were obtained in the same manner as in Example 8 except that the water-absorbing resin D was used. The absorption capacity of the obtained water-absorbent resin particles E was 33 g / g, and the absorption capacity of physiological saline under a pressure of 0.7 psi was 19 times.

[0043]

According to the method for producing a water-absorbing material of the present invention, an appropriate amount of water can be uniformly and rapidly supplied to the entire fine powder by supplying water to the fine powder layer of the water-absorbing resin. By pressurizing the water-absorbing fine powder layer, the whole fine powder is satisfactorily bonded and integrated, and a water-absorbing material having high water-absorbing performance and easy to handle is obtained.

As a result, a water-absorbing material having excellent water-absorbing performance can be manufactured with high productivity.

[Brief description of the drawings]

FIG. 1 is a step-by-step manufacturing process diagram illustrating an embodiment of the present invention.

FIG. 2 is a manufacturing process diagram showing a manufacturing process of water-absorbing material particles.

FIG. 3 is a manufacturing process diagram showing a manufacturing process of the shredded water-absorbing material.

FIG. 4 is a schematic layout diagram of a manufacturing apparatus showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Support stand 20 Fine powder 22 Fine powder layer 25 Water absorbing material sheet 26 Water absorbing material particles 28 Shredded water absorbing material 30 Water 40 Press plate 50 Crusher 54 Cutting machine

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08L 3:04 33:02 71:02 (72) Inventor Eri Goto 992 Nishioki, Akihama-ku, Aboshi-ku, Himeji-shi, Hyogo 1 F-term in Nippon Shokubai Co., Ltd. (reference) 4F070 AA03 AA12 AA29 AA52 AB13 DA45 DA48 DA52 4F201 AD08 AE05 AG01 AH81 BA02 BC01 BC12 BD02 BL03 BL05 BN21 BN29 4G066 AA14D AB05D AB06D AC17B AC35B AE06B BA05 BA09 FA20 FA33 FA37 FA40

Claims (8)

[Claims] 1. A method for producing a water-absorbing material using fine powder of a water-absorbent resin, comprising: (a) depositing the fine powder of the water-absorbent resin on a thin layer
Supplying water to the fine powder layer (b); and pressurizing the water-absorbing fine powder layer supplied with the water (c).
And (d) drying the pressed water-absorbing fine powder layer. 2. The method according to claim 1, wherein after the pressing step (c), the drying step is performed.
The method for producing a water-absorbing material according to claim 1, further comprising a step (e) of chopping the pressurized water-absorbing fine powder layer before or after (d). 3. The method for producing a water absorbing material according to claim 1, further comprising a step (f) of pulverizing the dried fine powder layer after the drying step (d). 4. The method according to claim 1, wherein said depositing step (a) forms a fine powder layer having a basis weight of 10 to 2000 g / m ² .
3. The method for producing a water-absorbing material according to any one of 3. 5. The method for producing a water absorbing material according to claim 1, wherein said depositing step (a) deposits said fine powder having a size passing through a 212 μm sieve. 6. The method for producing a water-absorbing material according to claim 1, wherein said water supply step (b) supplies 1 to 500 parts by weight of water with respect to 100 parts by weight of said fine powder. 7. The method for producing a water-absorbing material according to claim 2, wherein the shredding step (e) cuts the water-absorbing fine powder layer into a maximum length of 0.5 to 100 mm. 8. The method for producing a water-absorbing material according to claim 3, wherein said crushing step (f) crushes said dried fine powder layer to an average particle size of 200 to 800 μm.