Highly water-absorbent resin composition and method for producing the same

Abstract

The superabsorbent polymer composition and its manufacturing method according to the present invention are characterized by having excellent deodorizing power while minimizing deterioration in the physical properties of the superabsorbent polymer, by controlling the combination and mixing ratio of persimmon extract, glycine, and a chelating agent and mixing them with the superabsorbent polymer.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0182257 dated December 22, 2022 and Korean Patent Application No. 10-2023-0164000 dated November 23, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a superabsorbent polymer composition and a method for producing the same. Specifically, the present invention relates to a superabsorbent polymer composition having deodorizing and anti-odor properties and a method for producing the same. [Background technology]

[0003] Super absorbent polymers (SAPs) are synthetic polymers capable of absorbing 500 to 1,000 times their own weight in water, and different developers have given them different names, such as SAM (Super Absorbency Material) or AGM (Absorbent Gel Material). These super absorbent polymers first began to be used in sanitary products, and are now widely used in a variety of applications, including soil water retention agents in gardening, water-stopping materials in civil engineering and construction, seedling sheets, freshness-preserving agents in the food distribution industry, and compresses, in addition to sanitary products such as disposable baby diapers.

[0004] Such superabsorbent polymers are widely used in the field of sanitary materials, most often in diapers and sanitary napkins. In such sanitary materials, the superabsorbent polymer is generally contained in a dispersed state within the pulp. However, in recent years, efforts have been made to provide thinner sanitary materials, such as diapers. As part of these efforts, the development of so-called pulpless diapers, which contain less pulp or even no pulp at all, has been actively pursued.

[0005] In sanitary materials with a reduced pulp content or no pulp, the superabsorbent polymer is contained at a relatively high ratio, and these superabsorbent polymer particles are inevitably contained in multiple layers within the sanitary material. In order for the superabsorbent polymer particles contained in multiple layers to more efficiently absorb liquids such as urine, the superabsorbent polymer must fundamentally exhibit high absorption performance and absorption speed. In addition, the absorbed liquid must not leak even under external pressure, and the superabsorbent polymer must also have permeability to maintain its original shape even when swollen after absorbing liquid.

[0006] Therefore, much research has been conducted into improving the basic absorption and water retention of superabsorbent resins, such as by surface cross-linking.

[0007] However, superabsorbent polymers can be used in sanitary materials, and in this case, there is a problem that the unpleasant odor of absorbed liquids such as human and pet excrement can cause a poor usability. In particular, it is necessary to suppress both the odor originally contained in the absorbed liquid and the odor caused by bacteria that grow during use of the sanitary material containing the superabsorbent polymer.

[0008] Therefore, in the past, deodorizing substances were mixed into superabsorbent resins, but in order to effectively suppress odors, excessive amounts of deodorizing substances were mixed, which reduced absorption capacity, or the desired level of deodorizing capacity could not be achieved by emphasizing only antibacterial properties.

[0009] Therefore, there is a gradually increasing demand for superabsorbent polymers that not only have the basic properties of absorbency and water retention, but also have the ability to suppress odors. Therefore, there is a need to produce superabsorbent polymers that have excellent deodorizing properties. Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention provides a highly water-absorbent polymer composition having deodorizing or anti-odor properties and a method for producing the same.

[0011] More specifically, the present invention provides a superabsorbent polymer composition having excellent deodorizing power while minimizing deterioration of the physical properties of the superabsorbent polymer by controlling the combination and mixing ratio of deodorizing substances, and a method for producing the same. [Means for solving the problem]

[0012] In order to solve the above problems, the present invention provides the following superabsorbent polymer composition.

[0013] a superabsorbent resin comprising a base resin containing a crosslinked polymer obtained by crosslinking an acrylic acid-based monomer having at least a partially neutralized acidic group with an internal crosslinking agent, and a surface crosslinked layer formed on the surface of the base resin and obtained by additionally crosslinking the crosslinked polymer via a surface crosslinking agent; Contains persimmon extract, glycine, and a chelating agent.

[0014] The present invention also provides the following method for producing a superabsorbent polymer composition.

[0015] Step 1: forming a hydrogel polymer by cross-linking and polymerizing an acrylic acid monomer having at least a partially neutralized acid group in the presence of an internal cross-linking agent and a polymerization initiator; a step (step 2) of producing a base resin containing a crosslinked polymer by drying and pulverizing the hydrogel polymer; Step 3: Mixing the base resin with a surface cross-linking liquid to prepare a mixture; and (4) heat-treating the mixture to produce a superabsorbent resin having a surface cross-linked layer formed on the surface of the base resin, The mixture containing the persimmon extract and glycine is mixed with the surface cross-linking liquid in step 3, or mixed with the superabsorbent resin on which the surface cross-linked layer in step 4 has been formed, The chelating agent is mixed with the hydrogel polymer in step 1, mixed with the surface cross-linking liquid in step 3, or mixed with the highly water-absorbent resin on which the surface cross-linked layer has been formed in step 4. [Effects of the Invention]

[0016] As described above, the present invention is characterized by providing a superabsorbent polymer composition and a manufacturing method thereof that have excellent deodorizing power by applying a mixture containing persimmon extract and glycine in an optimal ratio and a chelating agent to the superabsorbent polymer. DETAILED DESCRIPTION OF THE INVENTION

[0017] The terms used in this specification are merely used to describe exemplary embodiments and are not intended to limit the present invention. The singular expressions include the plural expressions unless the context clearly dictates otherwise. It should be understood that the terms "comprise," "comprise," "have," and the like, as used herein, are intended to specify the presence of implemented features, steps, components, or combinations thereof, and do not preclude the presence or additional possibility of one or more other features, steps, components, or combinations thereof.

[0018] Since the present invention can be modified in various ways and can have various forms, specific examples are exemplified and described in detail below, but it is not intended to limit the present invention to the specific disclosed forms, and it should be understood that the present invention includes any modifications, equivalents, or alternatives falling within the spirit and technical scope of the present invention.

[0019] Since the present invention can be modified in various ways and can have various forms, specific examples are exemplified and described in detail below, but it is not intended to limit the present invention to the specific disclosed forms, and it should be understood that the present invention includes any modifications, equivalents, or alternatives falling within the spirit and technical scope of the present invention.

[0020] Hereinafter, the superabsorbent polymer composition and its manufacturing method will be described in more detail with reference to specific embodiments of the present invention.

[0021] Prior to this, the terminology used herein is merely for the purpose of referring to particular embodiments and is not intended to limit the present invention, and the singular forms used herein also include the plural forms unless the context clearly dictates otherwise.

[0022] For reference, in this specification, the term "superabsorbent polymer" may refer to the superabsorbent polymer itself depending on the context, or may be used to encompass all polymers that have been subjected to additional processes, such as surface crosslinking, pulverization, drying, pulverization, classification, etc., to be in a state suitable for commercialization.

[0023] In addition, in the present specification, the term "base resin" or "base resin powder" refers to a polymer obtained by polymerizing an acrylic acid-based monomer, which is dried and pulverized into a particle or powder form, and which has not yet been subjected to the surface modification or surface crosslinking steps described below.

[0024] (Super absorbent resin composition) According to one embodiment of the present invention, there is provided a superabsorbent polymer composition.

[0025] The superabsorbent polymer composition includes a base resin including a crosslinked polymer formed by crosslinking an acrylic acid-based monomer having at least a partially neutralized acidic group with an internal crosslinking agent, and a surface crosslinked layer formed on the surface of the base resin and formed by additional crosslinking of the crosslinked polymer via a surface crosslinking agent; persimmon extract; glycine; and a chelating agent.

[0026] The acrylic acid-based monomer may be any monomer commonly used in the production of superabsorbent resins. Specifically, the acrylic acid-based monomer may be a compound represented by the following Chemical Formula 1:

[0027] [Chemical formula 1] R1-COOM 1

[0028] In the above Chemical Formula 1, R1 is an alkyl group having 2 to 5 carbon atoms and containing an unsaturated bond, M 1 is a hydrogen atom, a monovalent or divalent metal, an ammonium group, or an organic amine salt.

[0029] Preferably, the acrylic acid monomer includes at least one selected from the group consisting of acrylic acid, methacrylic acid, and their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts.

[0030] The acrylic acid monomer may have an acidic group, and at least a portion of the acidic group may be neutralized. Preferably, the monomer may be partially neutralized with an alkaline substance such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide.

[0031] The degree of neutralization of the monomer may be 40 to 95 mol%, 40 to 80 mol%, or 45 to 75 mol%. The range of the degree of neutralization may vary depending on the final properties, but if the degree of neutralization is too high, the neutralized monomer may precipitate and polymerization may not proceed smoothly. Conversely, if the degree of neutralization is too low, the absorbency of the polymer may be significantly reduced and the polymer may exhibit properties similar to elastic rubber, which is difficult to handle.

[0032] Meanwhile, in order to improve the physical properties of the resin obtained by polymerization of the acrylic acid-based monomer, the polymerization is carried out in the presence of a crosslinking agent ("internal crosslinking agent"). The crosslinking agent is used to internally crosslink the hydrogel polymer and can be used separately from the "surface crosslinking agent" described below.

[0033] As the internal cross-linking agent, any compound can be used as long as it enables the introduction of cross-linking bonds during polymerization of the acrylic acid monomer. Non-limiting examples of the internal crosslinking agent include N,N'-methylenebisacrylamide, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, butylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipentaerythritol pentaacrylate, glycerin tri(meth)acrylate, pentaerythritol tetraacrylate, triallylamine, allyl (meth)acrylate, ethylene glycol diglycidyl ether, propylene glycol, glycerin, and ethylene carbonate. These crosslinking agents may be used alone or in combination.

[0034] The internal crosslinking agent may be added at a concentration of 0.001 to 1 wt %, or 0.01 to 0.8 wt %, or 0.1 to 0.7 wt % relative to the monomer composition. That is, if the concentration of the internal crosslinking agent is too low, the absorption rate of the resin may be reduced, resulting in weak gel strength, which is undesirable. Conversely, if the concentration of the internal crosslinking agent is too high, the absorption capacity of the resin may be reduced, resulting in an undesirable absorbent.

[0035] In addition, the base resin may further contain additives such as a thickener, a plasticizer, a storage stabilizer, and an antioxidant, if necessary.

[0036] The surface cross-linked layer is formed by additionally cross-linking a cross-linked polymer via a surface cross-linking agent. In this case, the surface cross-linking agent is not particularly limited as long as it is a compound that can react with a functional group of the polymer as a surface cross-linking agent generally used for surface cross-linking of a superabsorbent resin.

[0037] Preferably, in order to improve the properties of the resulting superabsorbent resin, the surface cross-linking agent can be one or more selected from the group consisting of polyhydric alcohol compounds; epoxy compounds; polyamine compounds; haloepoxy compounds; condensation products of haloepoxy compounds; oxazoline compounds; mono-, di-, or polyoxazolidinone compounds; cyclic urea compounds; polyvalent metal salts; and alkylene carbonate compounds.

[0038] Specifically, examples of polyhydric alcohol compounds that can be used include one or more selected from the group consisting of mono-, di-, tri-, tetra- or polyethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, 2,3,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerol, polyglycerol, 2-butene-1,4-diol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,2-cyclohexanedimethanol.

[0039] In addition, as the epoxy compound, ethylene glycol diglycidyl ether, glycidol, etc. can be used, and as the polyamine compound, one or more compounds selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, and polyamidepolyamine can be used.

[0040] The haloepoxy compound may be epichlorohydrin, epibromohydrin, or α-methylepichlorohydrin, while the mono-, di-, or polyoxazolidinone compound may be, for example, 2-oxazolidinone.

[0041] As the alkylene carbonate compound, ethylene carbonate or the like can be used. These may be used alone or in combination with each other. On the other hand, in order to increase the efficiency of the surface cross-linking step, one or more polyhydric alcohol compounds having 2 to 10 carbon atoms can be used among these surface cross-linking agents.

[0042] The content of the surface crosslinking agent to be added may be appropriately selected depending on the type of the surface crosslinking agent to be added and the reaction conditions, and it can usually be used in an amount of about 0.001 to about 5 parts by weight, preferably about 0.01 to about 3 parts by weight, more preferably about 0.05 to about 2 parts by weight, relative to 100 parts by weight of the polymer.

[0043] If the content of the surface cross-linking agent is too low, the surface cross-linking reaction hardly occurs, and if it exceeds 5 parts by weight per 100 parts by weight of the polymer, the surface cross-linking reaction may proceed excessively, resulting in a decrease in absorption capacity and physical properties.

[0044] Meanwhile, the surface cross-linking agent may further contain an inorganic substance. The inorganic substance may be one or more inorganic substances selected from the group consisting of silica, clay, alumina, silica-alumina composites, titanium, zinc oxide, and aluminum sulfate. The inorganic substance may be used in powder or liquid form, particularly alumina powder, silica-alumina powder, titanium powder, or nanosilica solution. The inorganic substance may be used in an amount of about 0.001 to about 1 part by weight per 100 parts by weight of the base resin.

[0045] The superabsorbent polymer composition of one embodiment of the present invention may contain persimmon extract and glycine as deodorizing substances. When the superabsorbent polymer composition is applied to a sanitary product, the persimmon extract and glycine have the effect of eliminating the odor that is inherent in liquids absorbed by the sanitary product and the effect of eliminating odors that may further occur due to bacterial growth during use.

[0046] The persimmon extract may be a substance extracted from persimmon leaves, persimmon trunks, persimmon fruits, or persimmon roots. In this disclosure, "extract" refers to the product obtained by extraction using an appropriate extraction solvent, and refers to any form that can be formed using the extract, such as the extract obtained by extraction, a diluted or concentrated solution of the extract, a dried product obtained by drying the extract, a purified product or fraction thereof, or a mixture thereof. However, when describing the amount contained, the amount to be mixed, the mixing ratio, etc. in this disclosure, the solid content of the persimmon extract is used as the basis.

[0047] Glycine can capture malodorous substances by chemically reacting with them. Malodorous substances generally have small molecular weights, so when they react with glycine, the malodor is reduced or becomes odorless, effectively eliminating the malodor. Glycine is particularly effective in reducing the malodor of aldehyde and ketone compounds.

[0048] Glycine may be contained in an amount of 100 to 200 parts by weight based on 100 parts by weight of the solid content of the persimmon extract. Preferably, glycine may be contained in an amount of 100 parts by weight or more, 120 parts by weight or more, 140 parts by weight or more, or 150 parts by weight or more to 200 parts by weight or less, 180 parts by weight or less, or 160 parts by weight based on 100 parts by weight of the solid content of the persimmon extract.

[0049] The persimmon extract may be included in an amount of 0.005 to 0.050 parts by weight based on the solid content per 100 parts by weight of the base resin. Specifically, the persimmon extract may be included in an amount of 0.005 parts by weight or more, 0.010 parts by weight or more, 0.015 parts by weight or more, 0.020 parts by weight or more, or 0.025 parts by weight or more to 0.050 parts by weight or less, 0.045 parts by weight or less, 0.040 parts by weight or less, 0.035 parts by weight or less, or 0.030 parts by weight or less based on the solid content per 100 parts by weight of the base resin.

[0050] Furthermore, glycine may be included in an amount of 0.005 to 0.050 parts by weight per 100 parts by weight of the base resin. Specifically, glycine may be included in an amount of 0.005 parts by weight or more, 0.010 parts by weight or more, 0.015 parts by weight or more, 0.020 parts by weight or more, 0.025 parts by weight or more, 0.030 parts by weight or more, or 0.035 parts by weight or more to 0.050 parts by weight or less, 0.045 parts by weight or less, or 0.040 parts by weight or less per 100 parts by weight of the base resin.

[0051] In order to maintain the inherent absorption properties of the superabsorbent polymer, maintain the color of the absorbent material white from an aesthetic point of view, and exhibit the level of deodorizing performance that the present invention aims to achieve, it is preferable that the deodorizing substance, persimmon extract or glycine, be contained within the above content range.

[0052] If the solid content of persimmon extract is 0.050 parts by weight or more, physical properties such as absorption capacity will decrease and the color of the absorbent will change from white to yellow, and if it is 0.005 parts by weight or less, there may be a problem that the desired deodorizing power is not achieved.

[0053] The superabsorbent polymer composition according to an embodiment of the present invention may contain a chelating agent. In the case of a hygiene product containing the superabsorbent polymer composition, if bacteria originating from the skin or the like come into contact with the absorbed liquid, the bacteria may grow, causing further odor. The chelating agent can inhibit the growth of such bacteria.

[0054] The chelating agent may include an aminoacetate-based chelating agent. Specifically, the aminoacetate-based chelating agent may include one or more selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), L-glutamic acid diacetate (GLDA), methylglycine diacetate (MGDA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethanoldiglycine acid (EDG), diethylenetriaminepentaacetic acid (DTPA), and salts thereof. More specifically, the chelating agent may be ethylenediaminetetraacetic acid (EDTA) or L-glutamic acid diacetate (GLDA).

[0055] The chelating agent may be included in an amount of 0.1 to 2.0 parts by weight per 100 parts by weight of the base resin. Specifically, the amount of the chelating agent may be 0.1 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, 0.7 parts by weight or more, or 1.0 parts by weight or more to 2.0 parts by weight or less, 1.5 parts by weight or less, or 1.3 parts by weight or less per 100 parts by weight of the base resin.

[0056] It is preferable that the chelating agent is contained within the above content range in order to achieve the level of antibacterial activity aimed at in the present invention while maintaining the inherent absorption properties such as the absorption capacity of the superabsorbent polymer, and to exhibit deodorizing ability by inhibiting the growth of bacteria due to the antibacterial activity.

[0057] If the amount of chelating agent mixed is 0.1 parts by weight or less, it is difficult to generate antibacterial activity sufficient to suppress bacteria, and if the amount of chelating agent mixed is 2.0 parts by weight or more, the physical properties of the superabsorbent resin itself may be reduced, such as a decrease in absorption capacity.

[0058] The superabsorbent polymer composition may further contain one or more additives selected from the group consisting of organic acids, iodine compounds, glycerin, and zinc chloride.

[0059] The organic acid may be one or more selected from the group consisting of citric acid, acetic acid, formic acid, fumaric acid, lactic acid, and propionic acid. Specifically, the organic acid may be citric acid. The organic acid may exhibit deodorizing effects in a superabsorbent resin, similar to persimmon extract or glycine. The organic acid also has the effect of neutralizing ammonia dissolved in urine.

[0060] The iodine compound may be a metal iodide salt. The metal iodide salt may be added during the manufacturing process in the form of a solution of I2 and at least one selected from the group consisting of CuI, NaI, and KI in water, or in the form of a powder obtained by drying the aqueous solution. Metal iodide salts, like persimmon extract or glycine, can also be added to superabsorbent polymers to impart deodorizing properties. Metal iodide salts eliminate malodorous substances by oxidizing them, and are generally effective against most malodorous substances.

[0061] The persimmon extract, glycine, and chelating agent may each be independently contained within the base resin or the surface cross-linked layer. Specifically, the persimmon extract or glycine may be contained within the surface cross-linked layer, and the chelating agent may be contained within the base resin or the surface cross-linked layer.

[0062] The persimmon extract, glycine, chelating agent, organic acid, or iodine compound may be mixed with the superabsorbent polymer in the form of an aqueous solution using water as a solvent, and be physically incorporated into the superabsorbent polymer, or may be mixed in the form of a powder, and be incorporated into the superabsorbent polymer in powder form.

[0063] (Method of producing superabsorbent resin composition) According to one embodiment of the present invention, there is provided a method for preparing a superabsorbent polymer composition.

[0064] The method for producing the superabsorbent polymer composition includes: The method includes the steps of: forming a hydrogel polymer by crosslinking and polymerizing an acrylic acid monomer having at least a partially neutralized acid group in the presence of an internal crosslinking agent and a polymerization initiator (Step 1); pulverizing and drying the hydrogel polymer to prepare a base resin containing the crosslinked polymer (Step 2); mixing the base resin with a surface crosslinking liquid to prepare a mixture (Step 3); and heat-treating the mixture to prepare a superabsorbent resin having a surface crosslinked layer formed on the surface of the base resin (Step 4). The mixture containing the persimmon extract and glycine is mixed with the surface cross-linking liquid in step 3, or mixed with the superabsorbent resin on which the surface cross-linked layer in step 4 has been formed, The chelating agent can be mixed into the hydrogel polymer in step 1, mixed into the surface cross-linking liquid in step 3, or mixed into the superabsorbent resin on which the surface cross-linked layer has been formed in step 4.

[0065] The method for producing superabsorbent polymers generally involves polymerizing acrylic acid monomers to produce a hydrogel polymer and then pulverizing the polymer. In addition, to improve various properties of the superabsorbent polymers, a method of crosslinking the surface of the produced superabsorbent polymers is used.

[0066] The present invention aims to provide a superabsorbent polymer composition having deodorizing properties by mixing the surface-crosslinked superabsorbent polymer with persimmon extract, glycine and a chelating agent.

[0067] The present invention will be described in detail below for each step.

[0068] (Step 1) Step 1 is a step of producing a hydrogel polymer, specifically, a step of cross-linking a monomer composition containing an acrylic acid-based monomer having at least a partially neutralized acid group to form a hydrogel polymer.

[0069] The acrylic acid-based monomer may be any monomer commonly used in the production of superabsorbent resins. Specifically, the acrylic acid-based monomer may be a compound represented by the following Chemical Formula 1:

[0070] [Chemical formula 1] R1-COOM 1

[0071] In the above Chemical Formula 1, R1 is an alkyl group having 2 to 5 carbon atoms and containing an unsaturated bond, M 1 is a hydrogen atom, a monovalent or divalent metal, an ammonium group, or an organic amine salt.

[0072] Preferably, the acrylic acid monomer includes at least one selected from the group consisting of acrylic acid, methacrylic acid, and their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts.

[0073] The acrylic acid monomer may have an acidic group, and at least a portion of the acidic group may be neutralized. Preferably, the monomer may be partially neutralized with an alkaline substance such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide.

[0074] The degree of neutralization of the monomer may be 40 to 95 mol%, 40 to 80 mol%, or 45 to 75 mol%. The range of the degree of neutralization may vary depending on the final properties, but if the degree of neutralization is too high, the neutralized monomer may precipitate and polymerization may not proceed smoothly. Conversely, if the degree of neutralization is too low, the absorbency of the polymer may be significantly reduced and the polymer may exhibit properties similar to elastic rubber, which is difficult to handle.

[0075] The monomer composition may contain a polymerization initiator that is generally used in the production of highly water-absorbent resins.

[0076] The polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator depending on the polymerization method, but a thermal polymerization initiator may also be included since a certain amount of heat is generated by UV irradiation and the polymerization reaction, which is an exothermic reaction, also generates a certain amount of heat in the photopolymerization method.

[0077] The photopolymerization initiator may be, for example, one or more compounds selected from the group consisting of benzoin ether, dialkyl acetophenone, hydroxyl alkyl ketone, phenyl glyoxylate, benzyl dimethyl ketal, acyl phosphine, and α-aminoketone. A specific example of an acyl phosphine is commercially available lucirin TPO, i.e., 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide. For more information on various photopolymerization initiators, see page 115 of Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Applications" (Elsevier, 2007).

[0078] The thermal polymerization initiator may be one or more compounds selected from the group consisting of persulfate initiators, azo initiators, hydrogen peroxide, and ascorbic acid. Specific examples of persulfate initiators include sodium persulfate (NaSO), potassium persulfate (KSO), and ammonium persulfate ((NH)SO). Furthermore, examples of azo initiators include 2,2-azobis(2-amidinopropane) dihydrochloride, 2,2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride, 2-(carbamoylazo)isobutylonitrile, 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, and 4,4-azobis-(4-cyanovaleric acid). Examples of thermal polymerization initiators include methyl methyl acrylate, methyl meth ...

[0079] The polymerization initiator may be added at a concentration of 0.001 to 1 wt %, or 0.005 to 0.1 wt %, based on the monomer composition. That is, if the concentration of the polymerization initiator is too low, the polymerization rate may be slowed and a large amount of residual monomer may be extracted into the final product, which is undesirable. Conversely, if the concentration of the polymerization initiator is too high, the polymer chains forming the network may be shortened, the content of water-soluble components may increase, and the physical properties of the resin may be degraded, such as reduced pressure absorption capacity, which is undesirable.

[0080] Meanwhile, the polymerization of the monomer composition is carried out in the presence of a crosslinking agent ("internal crosslinking agent") to improve the physical properties of the resin obtained by the polymerization of the acrylic acid-based monomer. The crosslinking agent is used to internally crosslink the hydrogel polymer and can be used separately from the "surface crosslinking agent" described below.

[0081] As the internal cross-linking agent, any compound can be used as long as it enables the introduction of cross-linking bonds during polymerization of the acrylic acid monomer. Non-limiting examples of the internal crosslinking agent include N,N'-methylenebisacrylamide, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, butylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipentaerythritol pentaacrylate, glycerin tri(meth)acrylate, pentaerythritol tetraacrylate, triallylamine, allyl (meth)acrylate, ethylene glycol diglycidyl ether, propylene glycol, glycerin, and ethylene carbonate. These crosslinking agents may be used alone or in combination.

[0082] The internal crosslinking agent may be added at a concentration of 0.001 to 1 wt %, or 0.01 to 0.8 wt %, or 0.1 to 0.7 wt % relative to the monomer composition. That is, if the concentration of the internal crosslinking agent is too low, the absorption rate of the resin may be reduced, resulting in weak gel strength, which is undesirable. Conversely, if the concentration of the internal crosslinking agent is too high, the absorption capacity of the resin may be reduced, resulting in an undesirable absorbent.

[0083] Furthermore, the cross-linking polymerization of the monomer composition may be carried out in the presence of a foaming agent depending on the need and extent of improvement in the absorption rate. Such foaming agents are decomposed during the cross-linking polymerization reaction to generate gas, which can form pores in the hydrogel polymer. As a result, the additional use of such foaming agents can form a more developed porous structure in the superabsorbent polymer, further improving the absorption rate of the superabsorbent polymer.

[0084] Non-limiting examples of the foaming agent include sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, calcium bicarbonate, calcium carbonate, magnesium bicarbonate, magnesium carbonate, azodicarbonamide (ADCA), dinitroso pentamethylene tetramine (DPT), p,p'-oxybis(benzenesulfonyl hydrazide) (OBSH), p-toluenesulfonyl hydrazide (TSH), sucrose stearate, The composition may contain one or more compounds selected from the group consisting of sucrose stearate, sucrose palmitate, and sucrose laurate.

[0085] The blowing agent may be present in the monomer composition in a content of 1000 to 4000 ppmw, more specifically, in a content of 1000 ppm or more, alternatively, 1100 ppm or more, alternatively, 1200 ppm or more, and 4000 ppmw or less, alternatively, 3500 ppmw or less, alternatively, 3000 ppmw or less.

[0086] In addition, the monomer composition may further contain additives such as a thickener, a plasticizer, a storage stabilizer, and an antioxidant, if necessary.

[0087] The monomer composition may be prepared in the form of a solution in which raw materials such as the acrylic acid-based monomer, polymerization initiator, internal crosslinking agent, and foaming agent are dissolved in a solvent.

[0088] In this case, any solvent can be used without limitation as long as it can dissolve the raw materials described above. For example, the solvent may be water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, propylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl amyl ketone, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol ethyl ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate, N,N-dimethylacetamide, or a mixture thereof.

[0089] The formation of the hydrogel polymer by polymerization of the monomer composition may be carried out by a conventional polymerization method, and the process is not particularly limited.

[0090] As a non-limiting example, the polymerization method can be broadly divided into thermal polymerization and photopolymerization depending on the type of polymerization energy source. Thermal polymerization can be carried out in a reactor having a stirring shaft such as a kneader, and photopolymerization can be carried out in a reactor equipped with a movable conveyor belt.

[0091] For example, the monomer composition is introduced into a reactor such as a kneader equipped with a stirring shaft, and then thermally polymerized by supplying hot air or heating the reactor to obtain a hydrogel polymer. Depending on the type of stirring shaft installed in the reactor, the hydrogel polymer discharged from the reactor outlet is obtained as particles ranging in size from several millimeters to several centimeters. Specifically, the obtained hydrogel polymer can be obtained in various forms depending on the concentration and injection rate of the monomer composition injected, but typically has a (weight-average) particle size of 2 to 50 mm.

[0092] As another example, when the monomer composition is photopolymerized in a reactor equipped with a movable conveyor belt, a sheet-like hydrogel polymer is obtained. The thickness of the sheet may vary depending on the concentration and injection rate of the monomer composition, but is preferably adjusted to a thickness of 0.5 to 10 cm to ensure uniform polymerization throughout the sheet while maintaining a stable production rate.

[0093] The hydrogel polymer formed in this manner may exhibit a water content of 40 to 80 wt%. Here, the water content is the weight of water in the total weight of the hydrogel polymer, and may be calculated by subtracting the weight of the polymer in a dry state from the weight of the hydrogel polymer. Specifically, it may be defined as a value calculated by measuring the weight loss due to evaporation of water in the polymer during the drying process by increasing the temperature of the polymer using infrared heating. Here, the drying conditions may be such that the temperature is increased from room temperature to about 180°C and then maintained at 180°C, with the total drying time being set to 20 minutes, including a 5-minute temperature increase step.

[0094] In the following step 2, a chelating agent can be mixed with the hydrogel polymer produced in step 1 before undergoing drying, pulverization, and classification steps. In step 1, the hydrogel polymer can be produced in a sheet shape, and the sheet can be cut into strips and mixed with the chelating agent by chopping while spraying the cut pieces.

[0095] The chelating agent may include an aminoacetate-based chelating agent. Specifically, the aminoacetate-based chelating agent may include one or more selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), L-glutamic acid diacetate (GLDA), methylglycine diacetate (MGDA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethanoldiglycine acid (EDG), diethylenetriaminepentaacetic acid (DTPA), and salts thereof. More specifically, the chelating agent may be ethylenediaminetetraacetic acid (EDTA) or L-glutamic acid diacetate (GLDA).

[0096] The chelating agent may be mixed in an amount of 0.1 to 2.0 parts by weight per 100 parts by weight of the base resin. Specifically, the amount of the chelating agent may be 0.1 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, 0.7 parts by weight or more, or 1.0 parts by weight or more to 2.0 parts by weight or less, 1.5 parts by weight or less, or 1.3 parts by weight or less per 100 parts by weight of the base resin.

[0097] In order to exhibit the deodorizing ability by inhibiting bacterial growth at the level sought in the present invention while maintaining the inherent absorption properties of the superabsorbent polymer, it is preferable that the chelating agent be included within the above content range.

[0098] The chelating agent can be mixed into the base resin in the form of an aqueous solution or a powder.

[0099] (Step 2) Step 2 of the present invention is a step of drying, pulverizing and classifying the hydrogel polymer produced in step 1 to form a base resin powder.

[0100] Specifically, the present invention may further include a step of coarsely pulverizing the hydrogel polymer before drying, which not only increases the drying efficiency of the hydrogel polymer but also affects the morphology of the superabsorbent polymer and various physical properties of the superabsorbent polymer, including the absorption rate. In particular, to improve the absorption rate of the superabsorbent polymer, the present invention may further include a step of coarsely pulverizing the hydrogel polymer before drying. Hereinafter, for convenience, the term "coarse pulverization" will be used in this specification to refer to pulverization before drying, to distinguish it from pulverization after drying.

[0101] The pulverizer used for the pulverization is not limited in configuration, and specifically may include any one selected from the group of pulverizing equipment consisting of a vertical pulverizer, a turbo cutter, a turbo grinder, a rotary cutter mill, a cutter mill, a disc mill, a shred crusher, a crusher, a chopper, and a disc cutter, but is not limited to the above examples.

[0102] In this case, the coarse grinding step can grind the hydrogel polymer to a particle size of about 2 mm to about 10 mm. Grinding to a particle size of less than 2 mm is technically difficult due to the high water content of the hydrogel polymer, and the ground particles may aggregate together. On the other hand, grinding to a particle size of more than 10 mm may result in little effect in increasing the efficiency of the subsequent drying step.

[0103] The drying may be carried out at a temperature of 120 to 250°C, 140 to 200°C, or 150 to 190°C. Here, the drying temperature can be defined as the temperature of the heat medium supplied for drying or the temperature inside a drying reactor containing the heat medium and polymer during the drying process. If the drying temperature is low and the drying time is long, process efficiency will decrease. To prevent this, the drying temperature is preferably 120°C or higher. If the drying temperature is higher than necessary, the surface of the hydrogel polymer may be overdried, resulting in increased fine powder generation in the subsequent pulverization step and reduced physical properties of the final resin. To prevent this, the drying temperature is preferably 250°C or lower.

[0104] At this time, the drying time in the drying step is not particularly limited, but may be adjusted to 20 to 90 minutes at the drying temperature in consideration of process efficiency and the physical properties of the resin.

[0105] The drying is carried out using a common medium, but may also be carried out by, for example, supplying hot air to the pulverized hydrogel polymer, irradiating it with infrared rays, microwave irradiation, or ultraviolet rays.

[0106] Preferably, this drying is carried out so that the dried polymer has a moisture content of 0.1 to 10 wt%. That is, if the moisture content of the dried polymer is less than 0.1 wt%, excessive drying can increase production costs and cause degradation of the crosslinked polymer, which is undesirable. If the moisture content of the dried polymer exceeds 10 wt%, defects can occur in subsequent processes, which is undesirable.

[0107] The dried hydrogel polymer can then be pulverized to optimize the surface area of the base resin powder and the superabsorbent polymer. The pulverization may be performed to obtain a particle size of 150 to 850 μm.

[0108] In this case, the crushing machine to be used may be a conventional one such as a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill, or a jog mill.

[0109] In addition, in order to control the physical properties of the superabsorbent resin to be manufactured as a final product, a step of selectively classifying particles having a particle size of 150 to 850 μm is carried out from the polymer particles obtained through the pulverization step.

[0110] The base resin powder can be obtained through the above classification steps. Such base resin powder may have a particle size of 150 to 850 μm and may contain 2 wt % or less, or 1 wt % or less, of fine powder having a particle size of less than 150 μm.

[0111] Furthermore, the method may further include a step of mixing zirconium phosphate after obtaining the base resin powder by drying and pulverizing. In this case, zirconium phosphate can be pre-mixed by dry mixing. That is, zirconium phosphate can be mixed as a solid into the base resin before surface crosslinking by a dry physical method. Zirconium phosphate is a substance that can physically adsorb malodorous substances. Therefore, by further mixing zirconium phosphate into the base resin powder, an additional deodorizing effect can be obtained.

[0112] In this case, zirconium phosphate may be included in an amount of 5.0 parts by weight or less per 100 parts by weight of the base resin. Zirconium phosphate may not be included to further increase deodorizing power, or if included, it may be included in an amount of at least 0.5 parts by weight, at least 0.8 parts by weight, at least 1.0 parts by weight, at least 1.3 parts by weight, at least 1.5 parts by weight, or at least 1.8 parts by weight, and at most 5.0 parts by weight, at most 4.0 parts by weight, at most 3.0 parts by weight, or at most 2.0 parts by weight. If too little zirconium phosphate is mixed, the deodorizing effect may be insignificant, while if too much is mixed, surface cross-linking may be insufficient, resulting in reduced absorbency under pressure.

[0113] (Step 3) Step 3 of the present invention is a step of mixing the base resin powder produced in step 2 with a surface cross-linking liquid.

[0114] The surface cross-linking liquid used in step 3 contains a surface cross-linking agent, and the surface cross-linking agent is not particularly limited as long as it is a surface cross-linking agent generally used for surface cross-linking of a superabsorbent resin and is a compound capable of reacting with a functional group possessed by the polymer.

[0115] Preferably, in order to improve the properties of the resulting superabsorbent resin, the surface cross-linking agent can be one or more selected from the group consisting of polyhydric alcohol compounds; epoxy compounds; polyamine compounds; haloepoxy compounds; condensation products of haloepoxy compounds; oxazoline compounds; mono-, di-, or polyoxazolidinone compounds; cyclic urea compounds; polyvalent metal salts; and alkylene carbonate compounds.

[0116] Specifically, examples of polyhydric alcohol compounds that can be used include one or more selected from the group consisting of mono-, di-, tri-, tetra- or polyethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol, 2,3,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerol, polyglycerol, 2-butene-1,4-diol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, and 1,2-cyclohexanedimethanol.

[0117] In addition, as the epoxy compound, ethylene glycol diglycidyl ether, glycidol, etc. can be used, and as the polyamine compound, one or more compounds selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine, and polyamidepolyamine can be used.

[0118] The haloepoxy compound may be epichlorohydrin, epibromohydrin, or α-methylepichlorohydrin, while the mono-, di-, or polyoxazolidinone compound may be, for example, 2-oxazolidinone.

[0119] As the alkylene carbonate compound, ethylene carbonate or the like can be used. These may be used alone or in combination with each other. On the other hand, in order to increase the efficiency of the surface cross-linking step, one or more polyhydric alcohol compounds having 2 to 10 carbon atoms may be included in these surface cross-linking agents and used.

[0120] The content of the surface crosslinking agent to be added may be appropriately selected depending on the type of the surface crosslinking agent to be added and the reaction conditions, and usually, about 0.001 to about 5 parts by weight, preferably about 0.01 to about 3 parts by weight, more preferably about 0.05 to about 2 parts by weight, can be used relative to 100 parts by weight of the polymer.

[0121] If the content of the surface cross-linking agent is too low, the surface cross-linking reaction hardly occurs, and if it exceeds 5 parts by weight per 100 parts by weight of the polymer, the surface cross-linking reaction may proceed excessively, resulting in a decrease in absorption capacity and physical properties.

[0122] Meanwhile, the surface cross-linking liquid may further contain an inorganic substance to form a surface cross-linked layer. Such inorganic substances may be one or more inorganic substances selected from the group consisting of silica, clay, alumina, silica-alumina composites, titanium, zinc oxide, and aluminum sulfate. The inorganic substance may be used in powder or liquid form, particularly alumina powder, silica-alumina powder, titanium powder, or nanosilica solution. The inorganic substance may be used in an amount of about 0.001 to about 1 part by weight per 100 parts by weight of the base resin.

[0123] Furthermore, a mixture containing persimmon extract and glycine can be mixed with the base resin together with the surface cross-linking liquid. The persimmon extract and glycine chemically bond with volatile malodorous substances such as aldehydes, thereby imparting deodorizing power to the superabsorbent resin.

[0124] Glycine may be contained in an amount of 100 to 200 parts by weight based on 100 parts by weight of the solid content of the persimmon extract. Preferably, glycine may be contained in an amount of 100 parts by weight or more, 120 parts by weight or more, 140 parts by weight or more, or 150 parts by weight or more to 200 parts by weight or less, 180 parts by weight or less, or 160 parts by weight based on 100 parts by weight of the solid content of the persimmon extract.

[0125] The persimmon extract may be mixed in an amount of 0.005 to 0.050 parts by weight based on the solid content relative to 100 parts by weight of the base resin. Specifically, the persimmon extract may be mixed in an amount of 0.005 parts by weight or more, 0.010 parts by weight or more, 0.015 parts by weight or more, 0.020 parts by weight or more, or 0.025 parts by weight or more to 0.050 parts by weight or less, 0.045 parts by weight or less, 0.040 parts by weight or less, 0.035 parts by weight or less, or 0.030 parts by weight or less based on the solid content relative to 100 parts by weight of the base resin.

[0126] Furthermore, glycine can be mixed in an amount of 0.005 to 0.050 parts by weight per 100 parts by weight of base resin. Specifically, glycine can be mixed in an amount of 0.005 parts by weight or more, 0.010 parts by weight or more, 0.015 parts by weight or more, 0.020 parts by weight or more, 0.025 parts by weight or more, 0.030 parts by weight or more, or 0.035 parts by weight or more to 0.050 parts by weight or less, 0.045 parts by weight or less, or 0.040 parts by weight or less per 100 parts by weight of base resin.

[0127] In order to maintain the inherent absorption properties of the superabsorbent polymer while exhibiting the level of deodorizing ability sought in the present invention, it is preferable that the deodorizing substance, persimmon extract or glycine, be contained within the above content range.

[0128] The deodorizing substance containing the persimmon extract and glycine can be mixed in the form of an aqueous solution or powder into the base resin together with the surface cross-linking liquid.

[0129] In addition, a chelating agent can be mixed into the base resin together with the surface cross-linking liquid. The type, amount and form of the chelating agent are explained in Step 1.

[0130] Meanwhile, the method of mixing the surface cross-linking liquid with the base resin is not particularly limited as long as the method can uniformly mix the surface cross-linking liquid with the base resin, and any method can be appropriately selected and used.

[0131] For example, a method in which the surface cross-linking liquid and the base resin are placed in a reaction tank and mixed, a method in which the surface cross-linking liquid is sprayed onto the base resin, a method in which the base resin and the surface cross-linking liquid are continuously supplied to a continuously operated mixer and mixed therewith, or the like may be used.

[0132] In this case, the surface cross-linking liquid may be an aqueous solution, and when the content of solids in the solution is 1 wt % or more, 3 wt % or more, 5 wt % or more, 10 wt % or more, or 50 wt % or less, 30 wt % or less, or 20 wt % or less, the surface cross-linking liquid is suitable for being uniformly dispersed in the base resin, and at the same time, aggregation of the base resin can be prevented.

[0133] (Step 4) Step 4 is a step for further improving the physical properties of the superabsorbent resin by reacting the base resin with the surface cross-linking liquid to form an interpenetrating polymer network on the surface of the cross-linked polymer contained in the base resin. Through this surface modification, a surface cross-linked layer is formed on the surface of the pulverized base resin particles.

[0134] The formation of the surface cross-linked layer may be carried out by a conventional method for increasing the cross-linking density on the surface of the polymer particles, for example, by mixing the pulverized polymer with a surface cross-linking liquid containing a surface cross-linking agent, and then heat-treating the mixture to cause a cross-linking reaction.

[0135] Step 4 may be carried out at a temperature of about 80°C to about 250°C. More specifically, the surface cross-linking process may be carried out at a temperature of about 100°C to about 220°C, or about 110°C to about 200°C, or about 120°C to about 190°C, for about 10 minutes to about 2 hours, or about 20 minutes to about 60 minutes. If the cross-linking reaction temperature is less than 160°C or the reaction time is too short, the surface cross-linking reaction may not occur sufficiently, resulting in low permeability. If the temperature exceeds 200°C or the reaction time is too long, the water retention capacity may decrease.

[0136] The temperature raising means for the surface crosslinking reaction is not particularly limited. Heating can be achieved by supplying a heat medium or directly supplying a heat source. In this case, the type of heat medium that can be used may be a heated fluid such as steam, hot air, or hot oil, but the present invention is not limited to these. The temperature of the heat medium to be supplied may be appropriately selected taking into consideration the means of the heat medium, the rate of temperature rise, and the target temperature of temperature rise. Meanwhile, the heat source to be directly supplied may be a method of heating through electricity or a method of heating through gas, but the present invention is not limited to the above-mentioned examples.

[0137] Furthermore, a mixture containing persimmon extract and glycine can be mixed with the superabsorbent resin having the surface cross-linked layer formed thereon. The amounts of persimmon extract and glycine to be mixed and the form in which they are mixed are as described in Step 3.

[0138] Furthermore, a chelating agent can be mixed with the superabsorbent resin on which the surface cross-linked layer has been formed. The type, amount and form of the chelating agent are as described in Step 1.

[0139] In addition, the superabsorbent resin having the surface cross-linked layer formed thereon may further be mixed with one or more additives selected from the group consisting of organic acids, iodine compounds, glycerin, and zinc chloride.

[0140] The organic acid may be one or more selected from the group consisting of citric acid, acetic acid, formic acid, fumaric acid, lactic acid, and propionic acid. Specifically, the organic acid may be citric acid. The organic acid may exhibit deodorizing effects in the superabsorbent resin, similar to a deodorizing substance.

[0141] The iodine compound may be a metal iodide salt. The metal iodide salt may be added in the form of a solution of I2 and at least one selected from the group consisting of CuI, NaI, and KI in water, or in the form of a powder obtained by drying an aqueous solution. Like deodorizing substances, the metal iodide salt can also be added to a superabsorbent polymer to impart deodorizing properties. The metal iodide salt oxidizes malodorous substances to remove malodors, and is generally effective against most malodorous substances.

[0142] The organic acid or iodine compound can be mixed in the form of an aqueous solution using water as a solvent or in the form of a powder.

[0143] When the deodorant substance and the chelating agent are added as an aqueous solution to the highly water-absorbent resin on which the surface cross-linked layer has been formed, a drying step may be further carried out thereafter.

[0144] Preferred examples are presented below to aid in understanding the invention, but the following examples are merely for illustrative purposes and are not intended to limit the scope of the invention.

[0145] Production example 1-Mixture A Persimmon extract and glycine were prepared as an aqueous solution by mixing 5 parts by weight of persimmon extract and 5 parts by weight of glycine based on the solid content with 100 parts by weight of the aqueous solution.

[0146] Production example 2-Mixture B Persimmon extract and glycine were prepared as an aqueous solution by mixing 5 parts by weight of persimmon extract and 7 parts by weight of glycine based on the solid content with 100 parts by weight of the aqueous solution.

[0147] Comparative Production Example 1-Mixture C Persimmon extract and methionine were prepared as an aqueous solution by mixing 5 parts by weight of persimmon extract and 5 parts by weight of methionine based on the solid content with 100 parts by weight of the aqueous solution.

[0148] Comparative Example 1 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0149] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0150] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was classified using a sieve to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0151] Comparative Example 2 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0152] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0153] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0154] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0155] Comparative Example 3 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0156] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0157] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0158] The surface-treated superabsorbent resin was mixed with 0.3 parts by weight of Mixture A in an aqueous solution state based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0159] Comparative Example 4 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0160] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0161] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0162] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0163] The surface-treated superabsorbent resin was mixed with 0.3 parts by weight of Mixture C in an aqueous solution state based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0164] Comparative Example 5 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0165] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0166] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0167] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0168] The surface-treated superabsorbent resin was mixed with an aqueous glycine solution so that the amount of glycine was 0.015 parts by weight based on 100 parts by weight of the base resin, and then subjected to a drying step at 80°C for 25 minutes.

[0169] Comparative Example 6 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0170] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips.

[0171] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0172] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0173] The surface-treated superabsorbent resin was mixed with an aqueous solution of persimmon extract so that the solid content of the persimmon extract was 0.015 parts by weight based on 100 parts by weight of the base resin, and then dried at 80°C for 25 minutes.

[0174] Comparative Example 7 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0175] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips.

[0176] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0177] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0178] The surface-treated superabsorbent resin was mixed with an aqueous glycine solution so that the amount of glycine was 0.015 parts by weight based on 100 parts by weight of the base resin, and then subjected to a drying step at 80°C for 25 minutes.

[0179] Example 1 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0180] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0181] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0182] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0183] The surface-treated superabsorbent resin was mixed with 0.1 parts by weight of Mixture A in the form of an aqueous solution based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0184] Example 2 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0185] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0186] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0187] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0188] The surface-treated superabsorbent resin was mixed with 0.3 parts by weight of Mixture A in an aqueous solution state based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0189] Example 3 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0190] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0191] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0192] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0193] The surface-treated superabsorbent resin was mixed with 0.5 parts by weight of Mixture A in an aqueous solution state based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0194] Example 4 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0195] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0196] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0197] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0198] The surface-treated superabsorbent resin was mixed with 0.1 parts by weight of Mixture B in the form of an aqueous solution based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0199] Example 5 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0200] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0201] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0202] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0203] The surface-treated superabsorbent resin was mixed with 0.3 parts by weight of Mixture B in the form of an aqueous solution based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0204] Example 6 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0205] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0206] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0207] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0208] The surface-treated superabsorbent resin was mixed with 0.5 parts by weight of Mixture B in the form of an aqueous solution based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0209] Example 7 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0210] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0211] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0212] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking liquid (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)). Furthermore, 0.3 parts by weight of Mixture A in the form of an aqueous solution was mixed with 100 parts by weight of the prepared base resin. Then, a surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain a superabsorbent resin with a particle size of 150 to 850 μm.

[0213] Example 8 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0214] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 1.0 part by weight based on 100 parts by weight of the base resin.

[0215] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0216] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0217] The surface-treated superabsorbent resin was mixed with 0.3 parts by weight of Mixture A in an aqueous solution state based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0218] Example 9 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0219] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0220] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0221] The surface-treated superabsorbent resin was mixed with an EDTA aqueous solution (EDTA concentration 40%) and Mixture A. The EDTA was mixed in an amount of 0.5 parts by weight per 100 parts by weight of the base resin. Mixture A was also mixed in an aqueous solution form at an amount of 0.3 parts by weight per 100 parts by weight of the base resin. This was followed by a drying step at 80°C for 25 minutes.

[0222] Example 10 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0223] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0224] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0225] The surface-treated superabsorbent resin was mixed with an EDTA aqueous solution (EDTA concentration 40%) and Mixture A. The EDTA was mixed in an amount of 1.0 part by weight per 100 parts by weight of the base resin. Mixture A was also mixed in an aqueous solution form at 0.3 parts by weight per 100 parts by weight of the base resin. This was followed by a drying step at 80°C for 25 minutes.

[0226] Example 11 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0227] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed with a GLDA aqueous solution (GLDA concentration 40%) by spraying and chopping (hole size 16 mm). The GLDA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0228] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0229] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0230] The surface-treated superabsorbent resin was mixed with 0.3 parts by weight of Mixture A in an aqueous solution state based on 100 parts by weight of the base resin, followed by a drying step at 80° C. for 25 minutes.

[0231] Example 13 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0232] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0233] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0234] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0235] The surface-treated superabsorbent resin was mixed with Mixture A and iodine-based aqueous solutions I2 and CuI (each with a concentration of 1%). Mixture A was mixed in an amount of 0.3 parts by weight per 100 parts by weight of the base resin in aqueous solution form, and 1.0 part by weight of the iodine-based aqueous solution was mixed per 100 parts by weight of the base resin. This was then dried at 80°C for 25 minutes.

[0236] Example 14 An aqueous monomer solution composition with a monomer concentration of 45.8 wt% was prepared by mixing 100 g of acrylic acid, 0.37 g of N,N'-methylenebisacrylamide as a crosslinker, 0.15 g of sodium persulfate (SPS) as a thermal initiator, 0.008 g of benzoin ether as a UV initiator, 40 g of caustic soda (NaOH), and 127 g of water. The aqueous monomer solution composition was then introduced into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and irradiated with ultraviolet light (irradiation dose: 10 mW / cm) using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C. 2 ) and UV polymerization was carried out for 2 minutes to produce a hydrogel polymer.

[0237] The produced hydrogel polymer was in the form of a sheet, which was then cut into strips. The cut hydrogel polymer was mixed by spraying an EDTA aqueous solution (EDTA concentration 40%) onto the sheet and chopping (hole size 16 mm) to mix. The EDTA was mixed to a ratio of 0.5 parts by weight based on 100 parts by weight of the base resin.

[0238] The hydrogel polymer was transferred to a meat chopper and cut into pieces of 2 mm to 10 mm. The water content of the cut hydrogel polymer was 47% by weight. The hydrogel polymer was then dried in a hot air dryer at 170°C for 30 minutes, and the dried hydrogel polymer was pulverized in a pin mill pulverizer. The polymer was then sieved to produce a base resin with a particle size of 150 μm to 850 μm.

[0239] Next, 100 parts by weight of the prepared base resin was uniformly mixed with a surface cross-linking solution (2.5 parts by weight of water, 0.1 part by weight of ethylene glycol diglycidyl ether (EX-810), 0.1 part by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 part by weight of silica (Aerosil A200)), and the surface cross-linking reaction was carried out at 140°C for 30 minutes. After the surface treatment was completed, the mixture was sieved to obtain superabsorbent resins with particle sizes of 150 to 850 μm.

[0240] The surface-treated superabsorbent resin was mixed with Mixture A and citric acid. Mixture A was mixed in an aqueous solution of 0.3 parts by weight per 100 parts by weight of the base resin, and citric acid was mixed in an aqueous solution (concentration 1%) of 1.0 part by weight per 100 parts by weight of the base resin. This was then dried at 80°C for 25 minutes.

[0241] [Table 1]

[0242] Experimental example The superabsorbent resin compositions prepared in the above Examples and Comparative Examples were measured for various physical properties by the following methods.

[0243] (1) Bacterial suppression rate 50 ml of artificial urine inoculated with E. coli at 3000 CFU / ml was added to 2 g of the superabsorbent resin of Comparative Example 1, and the mixture was cultured in an incubator at 35°C for 12 hours. After the culture was completed, the sample was thoroughly washed with 150 ml of saline (0.9 wt% sodium chloride solution) and cultured on a Nutrient Broth Agar (BD DIFCO) plate to measure the CFU (Colony Forming Unit; CFU / ml), which was then calculated as the physical property of the control group.

[0244] Two grams of the superabsorbent resin prepared in the above Examples or Comparative Examples was added to 50 ml of artificial urine inoculated with E. coli at 3,000 CFU / ml and cultured in an incubator at 35°C for 12 hours. After the culture was completed, 150 ml of saline (0.9 wt% sodium chloride solution) was added to the sample and shaken for one minute to ensure uniform mixing. The resulting diluted solution was smeared on a Nutrient Broth Agar (BD DIFCO.) plate and cultured in an incubator at 30°C for 24 hours, after which the CFU (Colony Forming Unit; CFU / ml) was measured.

[0245] Using the results of each measurement, the bacterial growth inhibition rate defined by the following formula 1 was calculated, and the antibacterial power of the superabsorbent resins according to each example and comparative example was evaluated based on this.

[0246] [Formula 1] Inhibition rate of bacterial growth = [1-{CFU(12 hours) / CFU control(12 hours)}] x 100(%)

[0247] In the above formula 1, CFU (12 hours) indicates the number of bacteria grown per unit volume of artificial urine (CFU / ml) when the superabsorbent resin is added to artificial urine inoculated with E. coli bacteria and then cultured at 35°C for 12 hours. CFU control (12 hours) indicates the number of bacteria grown per unit volume of artificial urine (CFU / ml) when artificial urine inoculated with the bacteria was cultured on the superabsorbent resin of Comparative Example 1 under the same conditions, i.e., the number of bacteria grown per unit volume of artificial urine (CFU / ml) measured for the control group.

[0248] (2) Deodorizing rate The deodorizing rate was measured using an adsorption tube method. 3-methylbutanal was selected as an aldehyde-based malodorous substance, and dimethyltrisulfide (DMTS) was selected as a sulfur compound-based malodorous substance to test the deodorizing power.

[0249] - Adsorption tube measurement method: 1g of superabsorbent resin was placed in a 500mL glass bottle, and 25mL of malodorous substances were poured into it. After aging for 3 hours in a thermostatic chamber, the sample was collected for 20 minutes. The temperature of the thermostatic chamber was 35℃ and the N2 flow rate was 250mL / min. The extruded malodorous substances were then adsorbed into the connected adsorption tube, and this was repeated twice for each sample. The collection results were analyzed by GC and confirmed.

[0250] Deodorizing power (%) = (amount of malodor of the reference sample (superabsorbent polymer of Comparative Example 1) measured by GC - amount of malodor of the sample measured by GC) / amount of malodor of the reference sample (superabsorbent polymer of Comparative Example 1) measured by GC × 100 (%)

[0251] (3)Centrifuge Retention Capacity (CRC) The water retention capacity of each resin in terms of its absorbency under no load was measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 241.3.

[0252] Specifically, resins were obtained from the resins obtained in the Examples and Comparative Examples, each of which was classified into a particle size range of 300 to 600 μm. W0 (g) (approximately 0.2 g) of this resin was evenly placed in a nonwoven fabric envelope, sealed, and then immersed in physiological saline (0.9 wt%) at room temperature. After 30 minutes, the envelope was centrifuged at 250 G for 3 minutes to remove water, and the mass of the envelope, W2 (g), was measured. The same procedure was repeated without the resin, and the mass, W1 (g), was then measured.

[0253] Using the obtained masses, the CRC (g / g) was calculated according to the following formula 1.

[0254] [Formula 1] CRC(g / g)={[W2(g)-W1(g)] / W0(g)}-1

[0255] (4) Absorbency under Pressure (AUP) The absorbency of the superabsorbent resins of the above Examples and Comparative Examples at a pressure of 0.7 psi was measured by EDANA method WSP242.3.

[0256] First, when measuring the absorbency under pressure, the resin fraction classified during the CRC measurement was used.

[0257] Specifically, a 400-mesh stainless steel iron net was attached to the bottom of a plastic cylinder with an inner diameter of 25 mm. Under conditions of room temperature and 50% humidity, W0 (g) of superabsorbent resin was evenly spread on the iron net, and a piston capable of applying a uniform load of 0.7 psi was placed on top of it. The piston had an outer diameter slightly smaller than 25 mm, and there was no gap between it and the inner wall of the cylinder, so that its vertical movement was not hindered. At this point, the weight of the device, W3 (g), was measured.

[0258] A glass filter with a diameter of 90 mm and a thickness of 5 mm was placed inside a 150 mm diameter petroleum dish, and physiological saline solution composed of 0.9 wt% sodium chloride was poured so that it was flush with the top surface of the glass filter. A sheet of filter paper with a diameter of 90 mm was placed on top of it. The measuring device was placed on top of the filter paper and allowed to absorb the liquid under load for one hour. After one hour, the measuring device was lifted and its weight W4 (g) was measured. Using the obtained masses, the pressurized absorption capacity (g / g) was calculated using the following equation 2.

[0259] [Formula 2] AUP(g / g) = [W4(g)W3(g)] / W0(g)

[0260] The results of the above experiment are shown in Table 2.

[0261] [Table 2]

[0262] According to the results in Table 2, the Examples have excellent bacteria inhibition rate and deodorizing rate while maintaining a similar level of absorption capacity compared to Comparative Example 1 without any additives.

[0263] In addition, in the case of Comparative Example 2, in which only a chelating agent was used without a deodorizing substance, the bacterial inhibition rate was at a similar level, but the deodorizing rate was very poor, and in Comparative Examples 3, 6, and 7, in which only a deodorizing substance was used without a chelating agent, bacteria could not be inhibited at all, and the deodorizing rate also tended to be lower than in the Examples.

[0264] In the case of Comparative Example 4, in which methionine was used instead of glycine, excellent deodorizing effects were not exhibited simultaneously against both aldehyde-based and sulfur-based compounds, as compared with the Examples.

[0265] Furthermore, it was confirmed that in the case of Comparative Example 5, which contained a chelating agent and glycine but no persimmon extract, the deodorizing rates for both aldehyde-based and sulfur compound-based odors were inferior to those of the Examples.

Claims

1. a superabsorbent resin comprising a base resin containing a crosslinked polymer obtained by crosslinking an acrylic acid-based monomer having at least a partially neutralized acidic group with an internal crosslinking agent, and a surface crosslinked layer formed on the surface of the base resin, the surface crosslinked layer being obtained by additional crosslinking of the crosslinked polymer via a surface crosslinking agent; Persimmon extract, Glycine and a chelating agent, Super absorbent resin composition.

2. For 100 parts by weight of the base resin, The persimmon extract is contained in an amount of 0.005 to 0.050 parts by weight based on the solid content. The highly water-absorbent resin composition according to claim 1.

3. For 100 parts by weight of the base resin, The glycine is contained in an amount of 0.005 to 0.050 parts by weight. The highly water-absorbent resin composition according to claim 1.

4. Based on the solid content of the persimmon extract, per 100 parts by weight The glycine is contained in an amount of 100 to 200 parts by weight. The highly water-absorbent resin composition according to claim 1.

5. For 100 parts by weight of the base resin, The chelating agent is included in an amount of 0.1 to 2.0 parts by weight. The highly water-absorbent resin composition according to claim 1.

6. The superabsorbent polymer composition further contains one or more additives selected from the group consisting of organic acids, iodine compounds, glycerin, and zinc chloride. The highly water-absorbent resin composition according to claim 1.

7. The chelating agent includes an aminoacetate-based chelating agent. The highly water-absorbent resin composition according to claim 1.

8. The aminoacetate chelating agent includes at least one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), L-glutamic acid diacetic acid (GLDA), methylglycine diacetic acid (MGDA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethanoldiglycine acid (EDG), diethylenetriaminepentaacetic acid (DTPA), and salts thereof; The highly water-absorbent polymer composition according to claim 7.

9. The persimmon extract, glycine, and chelating agent are each independently contained within the base resin or the surface cross-linked layer. The highly water-absorbent resin composition according to claim 1.

10. Step 1: forming a hydrogel polymer by cross-linking and polymerizing an acrylic acid monomer having at least a partially neutralized acid group in the presence of an internal cross-linking agent and a polymerization initiator; a step (step 2) of producing a base resin containing a crosslinked polymer by drying and pulverizing the hydrogel polymer; Step 3: mixing the base resin with a surface cross-linking liquid to prepare a mixture; and (4) heat-treating the mixture to produce a superabsorbent resin having a surface cross-linked layer formed on the surface of the base resin, The mixture containing the persimmon extract and glycine is mixed with the surface cross-linking liquid of step 3, or mixed with the superabsorbent resin on which the surface cross-linked layer of step 4 has been formed, A chelating agent is mixed with the hydrogel polymer in step 1, mixed with the surface cross-linking liquid in step 3, or mixed with the superabsorbent resin on which the surface cross-linked layer has been formed in step 4. A method for producing a superabsorbent polymer composition.

11. For 100 parts by weight of the base resin, The persimmon extract is mixed in an amount of 0.005 to 0.050 parts by weight based on the solid content. A method for producing the highly water-absorbent resin composition according to claim 10.

12. For 100 parts by weight of the base resin, The glycine is mixed in an amount of 0.005 to 0.050 parts by weight. A method for producing the highly water-absorbent resin composition according to claim 10.

13. Based on the solid content of the persimmon extract, per 100 parts by weight The glycine is contained in an amount of 100 to 200 parts by weight. A method for producing the highly water-absorbent resin composition according to claim 10.

14. For 100 parts by weight of the base resin, The chelating agent is mixed in an amount of 0.1 to 2.0 parts by weight. A method for producing the highly water-absorbent resin composition according to claim 10.

15. After step 4, the superabsorbent resin having the surface cross-linked layer formed thereon is further mixing one or more additives selected from the group consisting of organic acids, iodine compounds, glycerin, and zinc chloride; A method for producing the highly water-absorbent resin composition according to claim 10.

16. The chelating agent includes an aminoacetate-based chelating agent. A method for producing the highly water-absorbent resin composition according to claim 10.

17. The aminoacetate chelating agent includes at least one selected from the group consisting of ethylenediaminetetraacetic acid (EDTA), L-glutamic acid diacetic acid (GLDA), methylglycine diacetic acid (MGDA), hydroxyethylethylenediaminetriacetic acid (HEDTA), ethanoldiglycine acid (EDG), diethylenetriaminepentaacetic acid (DTPA), and salts thereof; A method for producing the highly water-absorbent polymer composition according to claim 16.

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