JPH0580939B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to a method for producing a water-absorbing resin. More specifically, the present invention relates to a method for producing a water-insoluble polyacrylic acid-based water-absorbing resin with improved water-absorbing performance. <Prior art and problems to be solved by the invention> In recent years, sanitary products, pharmaceuticals, cosmetics, agriculture, food,
BACKGROUND ART Water-absorbing resins that can highly absorb moisture are used as water-absorbing and water-retaining materials in the fields of civil engineering and construction, household goods, and the like. Examples of such water-absorbing resins include cross-linked polyethylene oxide, cross-linked polyvinyl alcohol, cross-linked polyacrylic acid and its salts, cellulose-acrylic acid graft copolymers and their salts, starch-acrylonitrile graft copolymers hydrolysates, etc. Among them, polyacrylic acid-based water-absorbing resins are widely used because they have excellent water-absorbing properties such as water absorption amount and water absorption rate. In order to increase the water absorption rate, this polyacrylic acid-based water-absorbing resin is used in the form of a powder obtained by mechanically crushing a block-like polymer obtained by polymerization. In particular, recently there has been a demand for water absorbent resins with a high water absorption rate, and since the water absorption rate of water absorbent resins is proportional to the surface area, those made into fine particles and having a large surface area are used. However, when it is atomized by mechanical crushing means or the like, the crosslinks of the water-absorbing resin are broken or solubilized portions are generated, which significantly reduces water absorption performance such as water absorption amount and water absorption rate. In addition, due to atomization, a film tends to form on the surface of the particles where they come into contact with water, making it difficult for water to penetrate uniformly, and causing agglomeration of powder (macomo phenomenon) during water absorption, resulting in insufficient water absorption performance. There is a problem with not being able to fully demonstrate one's potential. For example, if currently commercially available powdered water-absorbing resins are further mechanically pulverized, the amount of water absorbed will drop by about half, and the water absorption rate will take more than 30 minutes to 24 hours, making it easy to cause the mako phenomenon. Become.
The pulverization performed to improve the water absorption rate as described above has the drawback that it causes solubilization due to crosslinking and the mako phenomenon, which significantly reduces the water absorption performance. In order to solve these drawbacks, JP-A-57-
Publication No. 168921 discloses a water-absorbent resin in which a highly water-absorbent polymer material such as a cross-linked polyacrylate is coated with a water-soluble polymer such as polyethylene glycol, which does not cause the mako phenomenon and has a high water absorption rate. It is stated that. However, the production of this resin requires an uneconomic process in which a water-soluble polymer is dissolved in a large amount of an organic solvent such as methanol, coated on a superabsorbent polymer material powder, and then a large amount of the solvent is distilled off under reduced pressure. Moreover, it is difficult to produce industrially safely because it uses an organic solvent. When water is used instead of an organic solvent such as methanol and a superabsorbent polymer material powder is coated with a mixture of water and polyethylene glycol, the resulting water absorbent resin suffers from a mako phenomenon and is insufficiently coated. However, it was not possible to obtain a suitable water absorption rate. Furthermore, in JP-A-58-42602, a hydrophilic crosslinked polymer having a hydroxyl group or a carboxy group is
It is disclosed that by dispersing in a dispersion medium such as methanol or ethanol and further crosslinking the surface with a crosslinking agent such as a polyvalent metal salt, the water absorption rate can be increased and the mako phenomenon can also be prevented. however,
This method also requires uneconomic steps such as using a large amount of solvent such as methanol or ethanol, performing surface treatment, filtering, and removing the solvent by drying under reduced pressure for a long time. , crosslinking with polyvalent metal salts, etc. alone was insufficient to improve the water absorption rate and prevent the mako phenomenon. In addition, water-absorbing resins have excellent water absorption amount and water absorption speed, and the gel strength after water absorption is high. Performance such as excellent fluidity is required. However, conventional polyacrylic acid-based water-absorbing resins have not been fully satisfactory in these respects. <Purpose> The present invention was made in view of the above-mentioned problems, and has excellent water absorption amount, water absorption rate, gel strength after water absorption, resin fluidity, etc., without using organic solvents such as lower alcohols. An object of the present invention is to provide a method for producing a water-absorbing resin that does not cause the mako phenomenon during use. <Means for solving the problem> The method for producing a water-absorbing resin of the present invention, which was made to solve the above-mentioned problems, is to prepare a powdered polyacrylic acid-based water-absorbing resin in the presence of a polyhydric alcohol and water. This method is characterized in that the resin is treated with an aluminum compound that can react with the resin. After the above treatment, the remaining moisture is dried by means such as heating, and the powder is suitably used in the form of powder. The polyacrylic acid-based water absorbent resin used in the present invention is a polymer or copolymer having at least an acrylic acid or acrylate monomer unit in the main chain; a polysaccharide-acrylic acid graft copolymer such as starch or cellulose; Examples include polymers and salts thereof. Examples of the polymer or copolymer having at least a monomer unit of acrylic acid or an acrylic acid salt in the main chain include polyacrylic acid, polyacrylate, acrylic acid-acrylate copolymer, etc. . Examples of the salt portion of the acrylate and polyacrylate include alkali metal salts such as sodium salt, potassium salt, and lithium salt, and organic base salts such as ammonium salt, triethylamine salt, and pyridine salt. These polymers can be modified to modify their properties such as hydrophilicity, if necessary.
It may also be a copolymer with acrylamide, N-vinylpyrrolidone, 2-hydroxyethylmethanol, or the like. Further, the above-mentioned polymer is preferably crosslinked, and known crosslinking means are used to produce the crosslinked product. For example, self-crosslinking by heating, using an oxidizing catalyst such as potassium persulfate, or using a crosslinking agent having two or more polymerizable unsaturated bonds such as N,N'-methylenebisacrylamide during polymerization. This is done by adding This resin is usually prepared by adding other copolymerized monomers and the above-mentioned crosslinking agent as necessary to an aqueous solution of acrylic acid and/or acrylate.
It is produced by polymerization, and when dried after polymerization, it becomes a block, which is then ground to an appropriate particle size using a grinder. For particle size, Tyler
In a standard sieve, preferably 5 to 400 meshes,
More preferably, one having 10 to 200 meshes is used. Emulsion polymerization or suspension polymerization yields small spheres, which may be further ground. In addition, polysaccharide-acrylic acid graft copolymers such as starch and cellulose and their salts can be produced by a conventional graft polymerization method using a catalyst such as cerium ammonium nitrate. It can be obtained by the method described. The polyhydric alcohol used in the present invention includes:
Ethylene glycol, 1,2-propanediol, 1,3-propanediol, butanediol (e.g. 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3
-butanediol, etc.), pentanediol (e.g., 1,5-pentanediol, 1,3-pentanediol, 2,3-pentanediol, etc.), hexanediol (e.g., 1,6-hexanediol, 2,5-hexane diol, etc.), diol, etc.), 2-methyl-2,4-pentanediol, 2-methyl-2,
Diols such as 3-butanediol; glycerin, trimethylolpropane, hexanetriol (e.g. 1,2,6-hexanetriol,
1,3,5-hexanetriol, etc.), triols such as triethanolamine; Tetraols such as pentaerythritol and diglycerin; Pentaols such as glycose and furanose; Hexaols such as sorbitol and mannite; Sucrose Examples include octaols such as; lower alkylene oxide adducts of the above compounds; copolymers of lower alkylene oxides, and the like. Two or more types of these polyhydric alcohols may be used in combination. Examples of the lower alkylene oxides include ethylene oxide (hereinafter referred to as EO) and propylene oxide (hereinafter referred to as EO).
PO), butylene oxide, etc. with 2 to 4 carbon atoms
Examples of polyhydric alcohols to which lower alkylene oxides are added include diethylene glycol, triethylene glycol, polyethylene glycol [average molecular weight (hereinafter referred to as MW): 200, 300, 400,
600, 1000, 2000, 6000, etc.], dipropylene glycol, tripropylene glycol, polypropylene glycol [MW: 200, 400, 1000, 2000,
4000 etc.], glycerin-EO adduct [MW: 400,
600, 1000, 3000, 4000, etc.], glycerin-PO adduct [MW: 400, 600, 1000, 3000, 4000, etc.],
Glycerin-EO(50)/PO(50) random adduct [MW: 2600 etc.], Glycerin-PO(80)-EO(20)
Examples include block adducts [MW: 3000 etc.], trimethylolpropane-EO adducts, trimethylolpropane-PO adducts, pentaerythritol-EO adducts, pentaerythritol-PO adducts, sorbitol-EO adducts, etc. . Copolymers of lower alkylene oxides include random copolymers and block copolymers, such as EO adducts of polypropylene glycol [MW:
2400, 3100, 4000, etc.] are examples. In addition, among the above compounds, for example, glycerin-
EO(50)/PO(50) random adduct is EO50
It refers to a compound randomly added by reacting a mixture of % by weight and 50% by weight of PO (all weight % is based on total alkylene oxide) with glycerin, and is a glycerin-PO(80)-EO(20) block adduct. means a compound obtained by adding 80% by weight of PO to glycerin and then adding 20% by weight of EO (both weight% have the same meaning as above). Among the above polyhydric alcohols, preferred are ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, 2-methyl-2,4-pentanediol, hexanetriol, glycerin, pentaerythritol, sorbitol, polyethylene glycol , polypropylene glycol, glycerin-EO adduct, glycerin-PO adduct, pentaerythritol-EO adduct, pentaerythritol-PO adduct, sorbitol-EO adduct, etc. More preferably, ethylene glycol,
Propanediol, butanediol, pentanediol, hexanediol, 2-methyl-2,4
- Pentanediol, hexanetriol, polyethylene glycol. The amount of the polyhydric alcohol added is 0.01 to 50% by weight based on the water absorbent resin, preferably
It is in the range of 0.1 to 20% by weight, more preferably in the range of 1 to 15% by weight. If the amount is less than 0.01% by weight, no effect will be observed, and if it exceeds 50% by weight, the water absorption capacity or fluidity of the powder will decrease, which is not preferable. In addition, it has been experimentally found that water-absorbent resins obtained using compounds to which lower alkylene oxide is not added among the above polyhydric alcohols have extremely good fluidity before water absorption. . Further, the aluminum compound used in the present invention may be any aluminum compound that can react with the carboxy group or carboxylate group of the polyacrylic acid-based water-absorbing resin, and these aluminum compounds can be used to cross-link the surface of the water-absorbing resin. Acts as an agent. Examples of the aluminum compounds include aluminum salts such as aluminum chloride, aluminum nitrate, aluminum sulfate, aluminum phosphate, and aluminum acetate; aluminum hydroxide; aluminum isopropoxide, aluminum ethoxide, aluminum tertiary-pitoxide, etc. Examples include aluminum alkoxide, etc.
Two or more types may be mixed and used. In particular, when used in the crosslinking reaction in the form of aluminum hydroxide sol or aluminum hydroxide gel immediately after precipitation, the reactivity is high, and therefore gel strength can be increased without significantly impairing water absorption, and unnecessary residues can be removed. It is preferable that it does not occur. This state is suitably obtained by reacting an aluminum salt with an aluminate or an aluminum salt with an alkali metal hydroxide in the presence of water. The above aluminum compound is 0.1 to 40% by weight, preferably 0.5 to 25% by weight, based on the water absorbent resin.
More preferably, it is added in an amount of 1 to 15% by weight. If the amount added is less than 0.1% by weight, crosslinking will be insufficient and it will not be possible to prevent the mako phenomenon, etc. If the amount added exceeds 40% by weight, the surface will be crosslinked excessively, resulting in a decrease in water absorption. The water used in the present invention is not particularly limited, and for example, ion exchange water, distilled water, tap water, etc. can be used, and the amount of water used is an amount sufficient to dissolve or disperse the aluminum compound or more. Generally, it is 1 to 10 times the amount (weight) of the aluminum compound, preferably 1 to 10 times the amount (weight) of the aluminum compound.
The amount used is about 8 times (by weight), more preferably about 2 to 6 times (by weight). The method for producing a water absorbent resin of the present invention is carried out by treating a powdered polyacrylic acid water absorbent resin with an aluminum compound that can react with the polyacrylic acid water absorbent resin in the presence of a polyhydric alcohol and water. After the above treatment, the remaining moisture is removed by heating and drying, but the polyhydric alcohol, which is a high boiling point component, remains in the water absorbent resin. More specifically, for example, the powdered polyacrylic acid-based water-absorbing resin and the aluminum compound are mixed in the presence of a polyhydric alcohol and water, and the mixture is dried. The mixing means is not particularly limited, and may include a Nauta mixer, a ribbon blender,
A conventional mixer such as a conical blender, Henschel mixer, or Laikai device can be used. For example, add the above resin to the mixer, and while stirring, dissolve (or decompose) the desired amount of polyhydric alcohol and aluminum compound in water. ) is added or sprayed, thoroughly mixed, and then dried in a drier to produce a water absorbent resin. Alternatively, an aqueous solution (or decomposition solution) of each of the polyhydric alcohol and the aluminum compound is prepared, and these are added to the resin at the same time, or after either the polyhydric alcohol solution or the aluminum compound solution is added, the other is added. It may be a method. In the above step, the reaction temperature is not particularly limited, but it is usually carried out at room temperature to 100°C, preferably room temperature to 60°C, and the reaction time is 1 to 120 minutes, preferably 2 to 30 minutes. Drying is carried out using a conventional dryer, such as a hot air circulation dryer or a vacuum dryer, and the drying temperature ranges from room temperature to 150°C.
Preferably it is carried out at 70 to 120°C. moreover,
In order to improve fluidity during mixing, crosslinking properties, etc.
Calcium chloride, zinc sulfate, etc. may be added. In addition, in the manufacturing method of the present invention, the most preferred embodiment of the method for preparing the crosslinking agent liquid used is as follows. (A) When using aluminum chloride and an alkali metal aluminate, such as sodium aluminate, as the aluminum compound (1) Add 8 parts by weight of aluminum chloride hexahydrate to 85 parts by weight of water.
Add and dissolve parts by weight with stirring. (2) Next, 8 parts by weight of sodium aluminate is gradually added while stirring. (3) It immediately becomes cloudy and aluminum hydroxide is formed, and the viscosity increases significantly and loses fluidity, but if stirring is continued, it becomes fluid and viscous again. Usually, it is preferable to stir for 20 minutes or more. (4) A crosslinking agent solution is prepared by adding 15 parts by weight of polyhydric alcohol to this solution and stirring to make a uniform solution. Note that the polyhydric alcohol may be added to the initial water. (B) When aluminum chloride and an alkali metal hydroxide, such as sodium hydroxide, are used as the aluminum compound (1) Dissolve 15.9 parts by weight of sodium hydroxide in 85 parts by weight of water. (2) Next, add aluminum chloride while stirring.
Gradually add 32 parts by weight of hexahydrate. (3) Hereafter, process in the same manner as (3) and (4) of (A) above. The crosslinking agent liquid prepared in this way is
It is preferable to use 100 to 300 parts by weight of the powdered polyacrylic acid-based water-absorbing resin per 100 parts by weight. In addition, when the above-mentioned cross-linking agent solution is allowed to stand still, aluminum hydroxide settles and separates, so
It is preferable to stir and disperse the mixture before use. The water absorbent resin obtained by the production method of the present invention is used in powder form, and its particle size is about 5 to 500 mesh, preferably 10 to
It is 200 metsushiyu. Additionally, if necessary, additives such as fluidity aids such as finely divided silica and talc, fillers, antioxidants, antifungal agents, bactericides, fragrances, colorants, and deodorants may be added to the product. You may. The water absorbent resin obtained by the production method of the present invention can be used in the same manner as conventional water absorbent resins. <Actions and Effects of the Invention> As described above, according to the method for producing a water-absorbing resin of the present invention, a water-absorbing resin with excellent water-absorbing performance can be produced easily and inexpensively. In other words, conventional manufacturing methods use large amounts of organic solvents such as alcohol that are flammable, explosive, and toxic in the coating and crosslinking processes, and require filtration, drying, and solvent recovery processes. On the other hand, according to the production method of the present invention, a water-absorbing resin can be obtained without using an organic solvent and with a simple operation.
The manufacturing process can be simplified, costs can be reduced, and the water-absorbing resin can be manufactured safely and industrially. Furthermore, the water-absorbing resin obtained by the production method of the present invention has various excellent water-absorbing properties as shown in Examples. For example, it exhibits a high water absorption amount and water absorption rate not only for water but also for solutions containing salts, such as human body excreta such as urine and blood. Conventional water-absorbing resins have a problem of low water-absorbing ability for salt solutions, but the water-absorbing resin obtained by the present invention can quickly absorb urine, blood, etc. In addition, the gel strength after water absorption is high, so it can retain water in a stable shape and has excellent water retention. Furthermore, since the water absorption phenomenon does not occur during water absorption, the water absorption speed can be significantly increased. In addition, conventional water-absorbing resins lack fluidity before absorbing water, so when producing final products using water-absorbing resins, such as disposable diapers and sanitary products, the resin supply port may become clogged. However, the water-absorbing resin obtained by the present invention has the advantage of being excellent in workability because it exhibits high fluidity before water absorption. Since it has the above-mentioned advantages, the water-absorbing resin obtained by the production method of the present invention can be used for various purposes, and has a high water absorption amount and water absorption rate, and is excellent in water retention and gel strength after water absorption, so it can be used for various purposes, such as sanitary materials such as disposable diapers, sanitary napkins, sanitary tampons, and paper towels; medical materials such as water retention materials for poultices; agricultural materials such as seed germination aids and soil water retention materials; condensation prevention materials for interior materials, etc. It can be used in construction materials, cosmetics, and materials for perfumery products such as water-retaining materials for perfumes. <Examples> Next, examples and comparative examples of the present invention will be shown,
The present invention is not limited to these examples. In addition, in the examples, % indicates weight % unless otherwise specified. Furthermore, the performance test of the water-absorbing resin was conducted by the following method. (a) Measurement of water absorption Fold a commercially available coffee filter, place the sample (Xg) inside it, soak it in 0.9% saline for a certain period of time, and then measure its weight (Yg) including the coffee filter. On the other hand, the weight of the coffee filter itself that has absorbed water (Zg)
was measured, and the water absorption amount (times) was determined from the following formula. Water absorption (times) = (Y-Z)/X (b) Measurement of gel strength Add 98g of 0.9% saline to a 200ml beaker,
While stirring with a magnetic stirrer, 2 g of water absorbent resin is added and gelatinized. After leaving the resulting gel for 24 hours, the diameter will vary from 3/16 inch to 1/2 inch.
Steel balls for JIS standard ball bearings whose diameter increases by 16 inches are successively placed on the gel surface until they settle into the gel. However, the steel balls that do not settle are removed before the next steel ball is placed. In this way, the maximum diameter of the steel balls that did not settle was defined as the gel strength. (c) Measurement of fluidity Using a hollow cylindrical container (inner diameter 43 mmφ) with a bottom plate with a circular hole (diameter 15 mmφ) formed in the center, 150 ml of dry water absorbent resin was poured into the container with the circular hole closed. Add. Thereafter, the circular hole in the bottom plate is opened and the water-absorbing resin is allowed to fall. After falling,
The angle formed by the resin surface remaining in the container and the bottom plate was determined, and that angle was taken as fluidity. Comparative Example 1 Commercially available sodium polyacrylate-based self-crosslinking water-absorbing resin powder produced by reverse-phase suspension polymerization [trade name: Aqua Keep 10SH, manufactured by Seitetsu Kagaku Kogyo Co., Ltd. (Japan)]
A 20% aqueous solution (25 parts by weight) of each aluminum compound shown in the table was added to 100 parts by weight of the mechanically pulverized product while stirring at high speed. 2～
After stirring for 3 minutes, the resin is placed in a dryer until the moisture content is approximately 7%.
dried until. A water absorption test was conducted on each of the resins thus obtained. The results are shown in the table. As shown in the table, when using an aqueous solution consisting only of aluminum compounds without containing polyhydric alcohol, the water-absorbing resin aggregates or adheres during mixing, making kneading difficult. This phenomenon is likely to occur. Furthermore, the water absorption rate was also insufficient.

[Table] Example 1 In place of the 20% aqueous solution of the aluminum compound in Comparative Example 1, an aqueous solution with the following composition using each aluminum compound and polyethylene glycol of each molecular weight shown in the table was used, and the same procedure as in Comparative Example 1 was carried out. A water-absorbing resin was produced using appropriate dosages and operations. The water absorption performance of the obtained water absorbent resin was measured, and the results are shown in the table. The mixture of the raw water absorbent resin fine particles and the aqueous solution remained in a powder state even without high-speed stirring, and no cohesive adhesion of the fine particles occurred, and the mixing properties were extremely good. In particular, when aluminum isopropoxide or a mixture of the same weight of sodium aluminate and aluminum chloride was used as the aluminum compound, the product remained in a nearly dry state even if left before drying. In addition, the water-retaining properties of the water-absorbing resins were all extremely good. Aqueous solution composition Total amount of aluminum compounds 20 parts by weight Polyethylene glycol 8 Ion exchange water 72

【table】

[Table] Example 2 30g of acrylic acid was neutralized with 75g of a 20% sodium hydroxide aqueous solution and 0.9% of acrylamide was added.
Add g and mix. As a catalyst, first add 3 g of a 1% concentration sodium dithionite aqueous solution,
After 30 seconds, 2 g of a 1% potassium persulfate aqueous solution and 2 g of a 1% aluminum nitrate aqueous solution were added, stirred for about 30 seconds, and allowed to stand for 5 minutes to polymerize. During this polymerization, the temperature within the system did not particularly rise.
Then, the obtained polymer is placed in a hot air circulation dryer.
By dehydrating and drying at 100°C for 24 hours, the polymer was dried and hardened into a plate shape. The cured polymer is then ground and passed through an 80 mesh Tyler standard sieve. After adding and mixing 100 parts by weight of the crosslinking material composition shown in the table to 100 parts by weight of the 80 mesh pass powder thus obtained, the powder was heated to 100°C in a hot air circulation dryer. , dehydrated and dried for 30 minutes. The water absorption performance of the obtained resin is shown in the table. In addition, as Comparative Examples 2 to 5, data using compositions that do not contain polyethylene glycol, aluminum compounds, etc. are also shown.

[Table] Example 3 30g of acrylic acid was neutralized with 75g of a 20% sodium hydroxide aqueous solution and 0.9% of acrylamide was added.
Add g and mix. After adding 3 g of a 1% potassium persulfate aqueous solution as a catalyst and stirring for about 30 seconds, polymerization was allowed to stand on a vat at 60° C. for 1 hour. Then, the obtained polymer was heated to 100% in a hot air circulation dryer.
By dehydrating and drying at ℃ for 24 hours, the polymer was dried and hardened into a plate shape. The cured polymer is then ground and passed through an 80 mesh Tyler standard sieve. 150 parts by weight of the powder of 80 mesh passes obtained in this manner was charged into a Raikai apparatus, and while stirring, 75 parts by weight of a crosslinking material composition having the composition shown below was added, and after mixing for 20 minutes, the obtained The wet powder was dried in a hot air circulating dryer at 100°C for 1.5 hours to obtain a water absorbent resin. Crosslinking agent composition (1) Ion-exchanged water 85 parts by weight (2) Polyhydric alcohol 15 (3) Aluminum chloride hexahydrate 8 (4) Sodium aluminate 8 The water absorption amount ( Water absorption rate), gel strength after water absorption, and fluidity of the resin before water absorption were tested. The results are shown in the table. As Comparative Example 6, a water-absorbing resin was prepared in the same manner as in Example 3 using a composition in which the polyhydric alcohol in the crosslinking agent composition was removed and 100 parts by weight of ion-exchanged water was used. I checked the performance. The results are also shown in the table. Example 4 A water absorbent resin was produced in the same manner as in Example 3 except that the crosslinking agent composition shown in the table was used as the crosslinking agent composition. Regarding the obtained water absorbent resin,
Water absorption amount (water absorption rate), gel strength after water absorption, and fluidity of the resin before water absorption were tested. The results are shown in the table. As is clear from the table and the table, the water-absorbing resin obtained according to the present invention exhibits excellent water absorption amount and water absorption rate, as well as excellent performance in terms of gel strength after water absorption and fluidity of the water-absorbing resin. In addition, the water absorbent resins obtained in Comparative Examples 1 to 6 are as follows:
When measuring the amount of water absorbed in the water absorption test, water drainage is poor in all cases, making it difficult to accurately measure the amount of water absorbed, and the one digit of the measured value of the amount of water absorption is an approximate value.

【table】

【table】

【table】

Claims (1)

[Claims] 1. A polyacrylic acid-based water-absorbent resin characterized in that a powdered polyacrylic acid-based water-absorbent resin is treated with an aluminum compound that can react with the powdered polyacrylic acid-based water-absorbent resin in the presence of a polyhydric alcohol and water. manufacturing method. 2. The polyacrylic acid-based water-absorbent resin according to claim 1, wherein the polyacrylic acid-based water-absorbent resin is a crosslinked product of a polymer having at least a monomer unit of acrylic acid or an alkali metal salt of acrylic acid in the main chain. Method of manufacturing resin. 3 The aluminum compound is aluminum chloride,
One type or a mixture of two or more types selected from the group consisting of aluminum nitrate, aluminum sulfate, aluminum phosphate, aluminum acetate, aluminum hydroxide, aluminum isopropoxide, aluminum ethoxide, and aluminum tertiary-butoxide. A method for producing a polyacrylic acid-based water absorbent resin according to claim 1 above. 4. The method for producing a polyacrylic acid-based water absorbent resin according to claim 3, wherein the aluminum compound is aluminum hydroxide. 5. The polyacrylic acid-based water absorbent according to claim 4, wherein the aluminum hydroxide is an aluminum hydroxide gel formed by a reaction between an aluminum salt and an aluminate, or an aluminum salt and an alkali metal hydroxide. method for producing synthetic resin. 6 The polyhydric alcohol is ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, 2-methyl-2,4-
Pentanediol, hexanetriol, glycerin, pentaerythritol, sorbitol, polyethylene glycol, polypropylene glycol, glycerin-ethylene oxide adduct, glycerin-propylene oxide adduct, pentaerythritol-ethylene oxide adduct, pentaerythritol-propylene oxide adduct, and sorbitol-ethylene oxide The method for producing a polyacrylic acid-based water-absorbing resin according to claim 1, wherein the polyacrylic acid water-absorbing resin is one or a mixture of two or more selected from the group consisting of adducts.