Superabsorbent polymer composition and preparation method thereof

Abstract

The present invention relates to a superabsorbent polymer composition and a preparation method thereof. Specifically, the present invention relates to a superabsorbent polymer composition and a preparation method thereof, in which the superabsorbent polymer composition uses specific additives in combination to improve deodorizing performance and odor prevention, thereby effectively suppressing primary odors generated from urine and the like when applied to products such as diapers and the like, and suppressing primary odors generated due to bacterial growth while products are worn.

Description

Superabsorbent resin composition and method for manufacturing the same

[0001] Cross-citation with related application(s)

[0002] The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0194490 filed December 24, 2024 and Korean Patent Application No. 10-2025-0206460 filed December 22, 2025, and all contents disclosed in the documents of said Korean patent applications are incorporated herein as part of the specification.

[0003] The present invention relates to a superabsorbent resin composition and a method for manufacturing the same. Specifically, by using a combination of specific additives, the deodorizing and odor-repelling power is improved, thereby effectively suppressing primary odors generated from urine, etc., and secondary odors generated due to bacterial growth during wear of the product when applied to products such as diapers, and the superabsorbent resin composition and a method for manufacturing the same.

[0004]

[0005] Super Absorbent Polymer (SAP) is a synthetic polymer material capable of absorbing 500 to 1,000 times its own weight in moisture, and developers name it by different names such as SAM (Super Absorbency Material) and AGM (Absorbent Gel Material). The above-mentioned super absorbent polymer began to be commercialized for sanitary devices, and is now widely used as a material for horticultural soil repair agents, waterproofing materials for civil engineering and construction, seedling sheets, freshness preservation agents in the food distribution sector, and for compresses, in addition to sanitary products such as children's disposable diapers.

[0006] In most cases, these superabsorbent polymers are widely used in the field of hygiene products such as diapers and sanitary pads, but there has been a problem with reduced user comfort due to the odor of absorbed liquids, such as human and pet excrement, within these hygiene products. In addition, there is also a problem where secondary odors occur as the growth of bacteria accelerates within the absorbed liquid over time of wear.

[0007] To address this, various materials were used as adsorbents along with superabsorbent resins; however, these were utilized only for the removal of odors within simple body fluids and were not effective against secondary odors that arise over time due to bacterial growth, etc. In addition, there was a problem of actually degrading the basic absorption properties of the absorbent resins.

[0008] Accordingly, there is a growing demand for odor suppression as well as absorption and water retention, which are basic physical properties of superabsorbent resins. Therefore, there is a need to manufacture superabsorbent resins that can effectively suppress both deodorizing power and bacterial growth simultaneously.

[0009]

[0010] The present invention is intended to provide a superabsorbent resin composition and a method for manufacturing the same. More specifically, the present invention is intended to provide a superabsorbent resin composition and a method for manufacturing the same that effectively suppresses odors such as urine and bacterial growth when applied to products such as diapers by using a combination of specific additives.

[0011]

[0012] In order to solve the above problem, the present invention,

[0013] Polyacrylate (based) resin;

[0014] Cucurbituril; and

[0015] ethylenediaminetetraacetic acid or a salt thereof, comprising

[0016] A superabsorbent resin composition is provided.

[0017]

[0018] The present invention also provides a method for preparing a superabsorbent resin composition comprising the following steps:

[0019] A step of forming a hydrogel polymer by crosslinking an acrylic acid-based monomer having at least some neutralized acidic groups in the presence of an internal crosslinking agent (Step 1);

[0020] A step of preparing a base resin comprising a cross-linked polymer obtained by drying and grinding the above-mentioned hydrogel polymer (Step 2);

[0021] A step of preparing a surface crosslinking mixture by mixing the above base resin and the surface crosslinking composition (Step 3); and

[0022] The method comprises the step (step 4) of heat-treating the surface crosslinking mixture to produce a polyacrylic acid salt (based) resin in which a surface crosslinking layer is formed on the surface of the base resin, and

[0023] Cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof are each added independently in at least one of steps 3, 4, or after step 4.

[0024]

[0025] As described above, the present invention is characterized by providing a superabsorbent resin composition and a method for manufacturing that have excellent deodorizing power by combining a specific additive with a superabsorbent resin and inhibit the growth of bacteria to suppress additional odor generation.

[0026] In addition, the present invention is characterized by providing a superabsorbent resin composition and a method for manufacturing that effectively reduce phenolic odor components among various odor components that may occur under actual use conditions of the superabsorbent resin.

[0027]

[0028] The terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention.

[0029] The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, steps, components, or combinations thereof.

[0030] Terms such as first, second, third, etc. are used to describe various components, and these terms are used solely for the purpose of distinguishing one component from another.

[0031] The terms "polymer" or "polymer" used in this specification refer to a state in which water-soluble ethylene-based unsaturated monomers are polymerized, and may encompass all ranges of moisture content or particle size. Among the polymers, a polymer having a moisture content (water content) of about 40 weight% or more in the state before drying after polymerization may be referred to as a hydrogel polymer, and particles obtained by grinding and drying such hydrogel polymers may be referred to as a cross-linked polymer.

[0032] Furthermore, the terms “base resin” or “base resin powder” refer to a polymer formed by drying and grinding a polymer of acrylic acid-based monomers into particle or powder form, and refer to a polymer in a state where the surface modification or surface crosslinking steps described below have not been performed.

[0033] Additionally, the terms “polyacrylate salt(based) resin,” “superabsorbent resin,” or “superabsorbent resin powder” are used to encompass, depending on the context, a cross-linked polymer formed by polymerizing a water-soluble ethylene-based unsaturated monomer (acrylic acid-based monomer) containing acidic groups and having at least some of the acidic groups neutralized, or a base resin in the form of a powder made of superabsorbent resin particles formed by grinding the cross-linked polymer, or a state suitable for commercialization made by undergoing additional processes, such as surface cross-linking, fine powder reassembly, drying, grinding, classification, etc., with respect to the cross-linked polymer or the base resin.

[0034] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0035] Hereinafter, a method for manufacturing a superabsorbent resin and a superabsorbent resin will be described in more detail according to specific embodiments of the invention.

[0036]

[0037] (Superabsorbent resin composition)

[0038] According to one embodiment of the present invention, a superabsorbent resin composition is provided.

[0039] The above superabsorbent resin composition comprises a polyacrylic acid salt (based) resin; cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof.

[0040] According to one embodiment of the invention, the polyacrylic acid salt (based) resin comprises a crosslinked polymer in which an acrylic acid monomer having at least a portion of neutralized acidic groups is crosslinked with an internal crosslinking agent. Preferably, the polyacrylic acid salt (based) resin comprises a base resin comprising a crosslinked polymer in which an acrylic acid monomer having at least a portion of neutralized acidic groups is crosslinked with an internal crosslinking agent, and a surface crosslinking layer formed on the surface of the base resin, wherein the crosslinked polymer is further crosslinked via a surface crosslinking agent.

[0041]

[0042] Superabsorbent polymers are used in various hygiene products such as diapers and sanitary pads; however, there has been a problem where user comfort is degraded due to the inherent odor (primary odor) of excrement from humans and pets during actual use. Additionally, as time passes, bacterial growth is accelerated by various components present in the bodily fluids absorbed by the product, leading to the generation of additional odors (secondary odors). Various technologies are being developed to effectively control these odor-causing substances.

[0043] Conventionally, to reduce odors, deodorizing substances such as adsorbents were mixed with absorbent resins. However, to achieve the desired level of deodorizing power, an excessive amount had to be used relative to the resin content. In this case, the absorbent properties of the resin were significantly degraded, and there was a problem of increased product costs. Furthermore, conventional adsorbents had the problem of being unable to remove all secondary odors generated over time due to bacterial growth, in addition to the primary odor of the excrement itself.

[0044] Accordingly, the inventors have discovered that by using a combination of specific additives, odors caused by various factors can be effectively controlled without reducing the basic physical properties of the superabsorbent resin, namely absorption and water retention capacity, and have completed the present invention.

[0045] According to the present invention, when a product is applied, both primary odors originating from odor-generating substances contained in body fluids, urine, etc., and secondary odors resulting from bacterial growth can be effectively controlled, and in particular, phenolic compounds among the odor components can be effectively controlled. Furthermore, excellent deodorizing and deodorizing power can be achieved with a relatively small amount by using a combination of the two types of additives, making it economical, and in particular, it is desirable as it does not reduce absorption properties.

[0046]

[0047] First, the cucurbituril is a compound based on a cyclic arrangement of glycoluril subunits connected by methylene bridges. The cucurbituril exists as a mixture of two or more compounds, for example, a compound having a structure represented by the following chemical formula A, which can be denoted as CB(n) with the number of repeating units:

[0048] [Chemical Formula A]

[0049]

[0050] In the above formula, n can be an integer from 5 to 8.

[0051] Specifically, the cucurbituril may be one or more selected from the group consisting of CB[5], CB[6], CB[7] and CB[8], and more preferably, one or more selected from the group consisting of CB[6], CB[7] and CB[8].

[0052] Cucurbituril (CB) having the above structure is a material containing cavities within the molecule and is a component that achieves an excellent odor removal effect through binding with odor substances. In particular, the above cucurbituril is characterized by the fact that while the entire molecule is neutral, the interior of the molecule is highly hydrophobic and the exterior of the molecule is relatively hydrophilic. Due to these structural characteristics, it can form a strong bond with odor substances in an aqueous environment compared to general adsorbents.

[0053] Specifically, cucurbituril can form complexes with odor-causing substances very efficiently through host-guest chemistry. Due to the strong internal hydrophobicity of cucurbituril, the binding between cucurbituril and odor-causing substances is energetically more stable than the binding between cucurbituril and water, thereby achieving excellent odor reduction effects in watery excretions such as urine.

[0054] In particular, when the size of the malodorous substance and the pore size of the cucurbituril reach appropriate levels, the binding constant of the complex becomes very large. Most volatile malodorous substances have a size of 8 Å or less, which allows for the formation of a complex that satisfies Host-Guest Chemistry well when n of the cucurbituril is 5 to 8, more preferably 6 to 8.

[0055] In addition, the above cucurbituril is used in combination with ethylenediaminetetraacetic acid (or a salt thereof) described later to achieve a superior odor reduction effect.

[0056] In this regard, cationic substances are present in urine or body fluids, and cationic substances are also generated during the manufacturing process of neutralized acrylic acid. If cationic substances are present in excess, the proportion of cucurbituril binding to cationic substances instead of electrically neutral odor substances increases, and consequently, the odor reduction effect of cucurbituril may be somewhat reduced. However, in the present invention, cucurbituril is used in combination with ethylenediaminetetraacetic acid (or a salt thereof), so that ethylenediaminetetraacetic acid forms a strong bond with cationic substances, thereby enabling cucurbituril to effectively bind to odor substances.

[0057] Meanwhile, the ethylenediaminetetraacetic acid (or its salt) used in combination can inhibit the metabolic activity of bacteria, thereby reducing secondary odor substances resulting from bacterial growth, and some odor substances generated by the bacteria can be controlled by binding with cucurbituril. The specific odor reduction effect of ethylenediaminetetraacetic acid (or its salt) will be described later.

[0058] Therefore, when ethylenediaminetetraacetic acid and cucurbituril are used in combination, the odor reduction function of cucurbituril can be effectively performed through the mechanism of forming complexes with metal cations along with the bacterial growth inhibition mechanism of ethylenediaminetetraacetic acid. Accordingly, when primary odors originating from odor-generating substances contained in body fluids, urine, etc., and secondary odors resulting from bacterial growth can be effectively controlled when primary odor substances and products are applied.

[0059] The above cucurbituril may be included in an amount of 0.1 to 10 parts by weight per 100 parts by weight of polyacrylate salt (based) resin, and within the above content range, an excellent odor reduction effect can be achieved without degrading the basic absorption properties of the absorbent resin. Preferably, the amount may be 0.2 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, or 9 parts by weight or less, 7 parts by weight or less, 5 parts by weight or less, or 3 parts by weight or less.

[0060] Preferably, the cucurbituril may be included in the outermost layer of the polyacrylic acid salt(based) resin.

[0061] According to one embodiment of the invention, the polyacrylic acid salt (based) resin comprises a base resin and a surface cross-linking layer formed on the surface of the base resin, and accordingly, the cucurbituril may be included in at least one of the interior or the surface of the surface cross-linking layer of the resin. More preferably, it may be included on the surface of the surface cross-linking layer.

[0062]

[0063] The above ethylenediaminetetraacetic acid (EDTA) (or its salt) is a component that inhibits the generation of secondary odors caused by bacterial growth.

[0064] In sanitary materials to which superabsorbent resin is applied, as time passes while wearing, the growth of harmful bacteria in the odor-causing substances remaining in the product accelerates, and consequently, additional secondary odors are generated. The above-mentioned ethylenediaminetetraacetic acid (or salt thereof) can effectively reduce the generation of additional odors by inhibiting such bacterial growth.

[0065] The above-mentioned ethylenediaminetetraacetic acid (or its salt) can inhibit bacterial growth by forming salt crosslinks between cell membrane components and can destroy bacterial cell membranes. In particular, it has a very strong binding affinity with metal cations at pH values ​​such as urine and body fluids, allowing it to effectively destroy bacterial cell membranes compared to general chelating agents, thereby effectively inhibiting bacterial growth. Furthermore, the above-mentioned ethylenediaminetetraacetic acid (or its salt) is desirable for use in hygiene products because it has no skin toxicity.

[0066] In addition, when used in combination with the aforementioned cucurbituril, a superior odor reduction effect is achieved.

[0067] In this regard, cationic substances are present in urine or body fluids, and cationic substances are also generated during the manufacturing process of neutralized acrylic acid. If cationic substances are present in excess, the proportion of cucurbituril binding to cationic substances instead of electrically neutral odor substances increases, and consequently, the odor reduction effect of cucurbituril may be somewhat reduced. However, in the present invention, by using a combination of cucurbituril and ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid forms a strong bond with cationic substances, thereby enabling cucurbituril to effectively bind to odor substances.

[0068] Furthermore, the above ethylenediaminetetraacetic acid can inhibit the metabolic activity of bacteria to reduce secondary odor substances resulting from bacterial growth, and some odor substances generated by the bacteria can be controlled by combining with cucurbituril.

[0069] Therefore, when ethylenediaminetetraacetic acid and cucurbituril are used in combination, the odor reduction function of cucurbituril can be effectively performed through the mechanism of complex formation with metal cations, along with the bacterial growth inhibition mechanism of ethylenediaminetetraacetic acid. Accordingly, when the product is applied, both primary odors originating from odor-causing substances contained in body fluids, urine, etc., and secondary odors resulting from bacterial growth can be effectively controlled.

[0070] Preferably, the ethylenediaminetetraacetic acid (or its salt) may be included in the outermost layer of the polyacrylic acid salt (system) resin.

[0071] According to one embodiment of the invention, the polyacrylic acid salt (based) resin comprises a base resin and a surface cross-linking layer formed on the surface of the base resin, and accordingly, the ethylenediaminetetraacetic acid (or salt thereof) may be included in at least one of the interior or surface of the surface cross-linking layer of the resin. More preferably, it may be included on the surface of the surface cross-linking layer.

[0072] The above ethylenediaminetetraacetic acid may also be used in the form of salts. Specifically, its salts include EDTA 2Na (ethylenediamine-N,N,N',N'-tetraacetic acid, disodium salt), dihydrate EDTA 3Na (ethylenediamine-N,N,N',N'-tetraacetic acid, trisodium salt, trihydrate), EDTA 4Na (ethylenediamine-N,N,N',N'-tetraacetic acid, tetrasodium salt), tetrahydrate EDTA 2K (ethylenediamine-N,N,N',N'-tetraacetic acid, disodium salt), dihydrate EDTA 2Li (ethylenediamine-N,N,N',N'-tetraacetic acid, disilicate salt), monohydrate EDTA (2NH4 ethylenediamine-N,N,N',N'-tetraacetic acid, disammonium salt), and EDTA Examples include 3K (ethylenediamine-N,N,N',N'-tetraacetic acid, tripotassium salt), dihydrate Ba(II)-EDTA (ethylenediamine-N,N,N',N'-tetraacetic acid, barium chelate), etc., and any one or more of these may be used.

[0073] The above ethylenediaminetetraacetic acid (or its salt) may be included in an amount of 0.01 to 2 parts by weight per 100 parts by weight of a polyacrylate salt (system) resin. When used within this content range, it can effectively inhibit bacteria without degrading the absorbent properties, thereby significantly improving the deodorizing and deodorizing power of the absorbent resin. Preferably, the amount may be 0.025 or more, 0.05 or more, 0.1 or more, 0.2 or more, 0.5 or more, and 2.0 or less, 1.8 or less, or 1.5 or less. The above ethylenediaminetetraacetic acid may be used in the form of a salt mixed with an aqueous solution, and the above content range is based on the solid content.

[0074]

[0075] Meanwhile, the above cucurbituril and ethylenediaminetetraacetic acid or salt thereof may be mixed in a weight ratio of 1:0.2 to 1 to 2, which is desirable as it can maximize the synergistic effect of the cucurbituril within the above mixing range. It is preferable that the above mixing range be appropriately controlled within the respective content ranges of the aforementioned cucurbituril and ethylenediaminetetraacetic acid or salt thereof.

[0076] If the ratio of ethylenediaminetetraacetic acid or its salt to cucurbituril is excessively low (less than a weight ratio of 1:0.2) outside the above mixing range, the effect of secondary odor control may be reduced, and if the ratio of ethylenediaminetetraacetic acid or its salt is excessively high (exceeding a weight ratio of 1:2), the effect of primary odor control may be reduced.

[0077] The above content range may more preferably be 1:0.25 to 1:2, 1:0.3 to 1:2, or 1:0.7 to 1:2. Within the said content range, the synergistic effect thereof may be further improved.

[0078]

[0079] As described above, the polyacrylic acid salt (based) resin comprises a crosslinked polymer in which an acrylic acid monomer having at least a portion of neutralized acidic groups is crosslinked with an internal crosslinking agent, and preferably, the polyacrylic acid salt (based) resin comprises a base resin comprising a crosslinked polymer in which an acrylic acid monomer having at least a portion of neutralized acidic groups is crosslinked with an internal crosslinking agent, and a surface crosslinking layer formed on the surface of the base resin in which the crosslinked polymer is further crosslinked via a surface crosslinking agent.

[0080]

[0081] The above acrylic acid-based monomer may be any monomer commonly used in the manufacture of superabsorbent resins. Specifically, the above acrylic acid-based monomer may be a compound represented by the following chemical formula 1:

[0082] [Chemical Formula 1]

[0083] R 1 -COOM 1

[0084] In the above chemical formula 1,

[0085] R 1 It is an alkyl group having 2 to 5 carbon atoms containing unsaturated bonds, and

[0086] M 1 It is a hydrogen atom, a monovalent or divalent metal, an ammonium group, or an organic amine salt.

[0087] Preferably, the acrylic acid monomer comprises one or more selected from the group consisting of acrylic acid, methacrylic acid, and their monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts.

[0088] The above acrylic acid-based monomer has an acidic group, and at least a portion of the acidic group may be neutralized. Preferably, the monomer may be used after being partially neutralized with an alkaline substance such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, etc.

[0089] At this time, the degree of neutralization of the monomer may be 40 to 95 mol%, or 40 to 80 mol%, or 45 to 75 mol%. The range of the degree of neutralization may vary depending on the final physical properties, but if the degree of neutralization is excessively high, the neutralized monomer may precipitate, making it difficult for polymerization to proceed smoothly; conversely, if the degree of neutralization is excessively low, not only is the absorption capacity of the polymer significantly reduced, but it may also exhibit properties such as elastic rubber that are difficult to handle.

[0090]

[0091] The above "internal crosslinking agent" is a term used to distinguish it from the "surface crosslinking agent" used to crosslink the surface of the base resin, and it serves to polymerize by crosslinking the unsaturated bonds of the aforementioned acrylic monomers. Although the crosslinking in the above step proceeds without distinction between the surface and the interior, due to the surface crosslinking process of the base resin described later, the particle surface of the finally manufactured superabsorbent resin is composed of a structure crosslinked by the surface crosslinking agent, and the interior is composed of a structure crosslinked by the internal crosslinking agent.

[0092] As the above internal crosslinking agent, any compound that enables the introduction of crosslinking bonds during the polymerization of the above acrylic acid-based monomer may be used. As a non-limiting example, the internal crosslinking agent is N,N'-methylenebisacrylamide, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol 400, 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, trialylamine, allyl (meth)acrylate, ethylene glycol Polyfunctional crosslinking agents such as diglycidyl ether, propylene glycol, glycerin, or ethylene carbonate may be used alone or in combination of two or more.

[0093] Such internal crosslinking agents may be added to the monomer composition at a concentration of 0.001 to 1 weight%, 0.01 to 0.8 weight%, or 0.1 to 0.7 weight%. That is, if the concentration of the internal crosslinking agent is excessively low, the absorption rate of the resin may be reduced and the gel strength may be weakened, which is undesirable. Conversely, if the concentration of the internal crosslinking agent is excessively high, the absorption capacity of the resin may be reduced, making it undesirable as an absorbent.

[0094] In addition, the above base resin may further include additives such as thickeners, plasticizers, preservation stabilizers, and antioxidants as needed.

[0095]

[0096] The superabsorbent resin comprises a surface cross-linked layer formed on the surface of the base resin, wherein the cross-linked polymer is additionally cross-linked via a surface cross-linking agent.

[0097] Preferably, the cucurbituril and ethylenediaminetetraacetic acid or its salt may each be independently included in the interior of the surface cross-linked layer or on the surface of the surface cross-linked layer. This may mean that the cucurbituril and ethylenediaminetetraacetic acid or its salt may each be independently introduced after the polymerization of the base resin (=before the surface cross-linking step), during the surface cross-linking step, or after the surface cross-linking step, and this will be explained in more detail in the method for manufacturing a superabsorbent resin composition described later.

[0098]

[0099] The above surface crosslinked layer is formed by additionally crosslinking a crosslinked polymer via a surface crosslinking agent. In this case, the surface crosslinking agent is a surface crosslinking agent generally used for surface crosslinking of superabsorbent resins, and any compound capable of reacting with the functional groups of the polymer is acceptable without any specific limitations.

[0100] Preferably, to improve the properties of the superabsorbent resin produced, one or more surface crosslinking agents selected from the group consisting of polyhydric alcohol compounds; epoxy compounds; polyamine compounds; haloepoxy compounds; condensation products of haloepoxy compounds; oxazolidinone compounds; mono-, di- or polyoxazolidinone compounds; cyclic urea compounds; polyhydric metal salts; and alkylene carbonate compounds may be used.

[0101] Specifically, examples of polyhydric alcohol compounds may 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.

[0102] In addition, ethylene glycol diglycidyl ether and glycidol may be used as epoxy compounds, and one or more selected from the group consisting of ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine, polyethyleneimine and polyamidepolyamine may be used as polyamine compounds.

[0103] And as haloepoxy compounds, epichlorohydrin, epibromohydrin, and α-methylepichlorohydrin can be used. Meanwhile, as mono-, di-, or polyoxazolidinone compounds, for example, 2-oxazolidinone can be used.

[0104] In addition, ethylene carbonate and the like can be used as alkylene carbonate compounds. These can be used individually or in combination with each other. Meanwhile, to increase the efficiency of the surface crosslinking process, at least one polyhydric alcohol compound having 2 to 10 carbon atoms can be included among these surface crosslinking agents.

[0105] The content of the surface crosslinking agent added above can be appropriately selected depending on the type of surface crosslinking agent added or the reaction conditions, but typically, about 0.001 to about 5 parts by weight, preferably about 0.01 to about 3 parts by weight, and more preferably about 0.05 to about 2 parts by weight can be used per 100 parts by weight of the polymer.

[0106] If the content of the surface crosslinking agent is excessively low, the surface crosslinking reaction hardly occurs, and if it exceeds 5 parts by weight per 100 parts by weight of the polymer, a decrease in water absorption capacity and physical properties may occur due to the progression of an excessive surface crosslinking reaction.

[0107]

[0108] Meanwhile, the surface crosslinking agent may additionally include an inorganic material. As such an inorganic material, one or more inorganic materials selected from the group consisting of silica, clay, alumina, silica-alumina composites, titania, zinc oxide, and aluminum sulfate may be used. The inorganic material may be used in powder or liquid form, and in particular, may be used as alumina powder, silica-alumina powder, titania powder, or a nano-silica solution. Additionally, the inorganic material 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.

[0109] In addition, the surface crosslinking agent may further include a thickening agent. By further crosslinking the surface of the base resin powder in the presence of the thickening agent, the degradation of physical properties can be minimized even after grinding. Specifically, one or more selected from polysaccharides and hydroxy-containing polymers may be used as the thickening agent. Gum-based thickening agents and cellulose-based thickening agents may be used as the polysaccharides. Specific examples of the above-mentioned gum-based thickeners include xanthan gum, arabic gum, karaya gum, tragacanth gum, ghatti gum, guar gum, locust bean gum, and psyllium seed gum, and specific examples of the above-mentioned cellulose-based thickeners include hydroxypropylmethylcellulose, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxymethylpropylcellulose, hydroxyethylhydroxypropylcellulose, ethylhydroxyethylcellulose, and methylhydroxypropylcellulose. Meanwhile, specific examples of the above-mentioned hydroxyl-containing polymers include polyethylene glycol and polyvinyl alcohol.

[0110]

[0111] A superabsorbent resin composition according to one embodiment of the invention provides excellent short-term deodorizing power. For example, after adding the superabsorbent resin composition to an odor solution and storing it at 35±0.5℃ for 2 hours, the concentration of phenolic odor components in the odor solution measured by solid-phase microextraction (SPME) can satisfy the values ​​of 1) and 2) below compared to the control group.

[0112] 1)C 1-6 The concentration of the alkoxyphenol compound is 50% or less, and

[0113] 2)C1-6 The concentration of the alkyl phenol compound is 50% or less, and

[0114] Here, the above odor solution is C as a phenolic odor component. 1-6 Alkoxyphenol compounds and C 1-6 It is a mixed solution containing an alkyl phenolic compound, and

[0115] The above control group is a superabsorbent resin composition that does not contain cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof.

[0116] The solid-phase microextraction (SPME) method for evaluating the short-term deodorizing power described above will be explained in more detail in the experimental examples described later.

[0117]

[0118] A superabsorbent resin composition according to one embodiment of the invention achieves excellent long-term deodorizing power in addition to the aforementioned short-term deodorizing power, for example, a superabsorbent resin composition in which, after mixing the superabsorbent resin composition with artificial urine inoculated with E. coli at 3000±300 CFU / ml and storing the mixed solution at 35±0.5℃ for 24 hours, the concentration of malodorous components in the mixed solution measured according to an adsorption tube experiment satisfies the values ​​1) and 2) below compared to the control group:

[0119] 1)C 1-6 The concentration of the alkoxyphenol compound is less than 5%, and

[0120] 2)C 1-6 The concentration of alkyl phenol compounds is 50% or less,

[0121] Here, the above mixed solution is C 1-6 Alkoxyphenol compounds and C 1-6 It contains phenolic malodorous components of alkyl phenolic compounds, and

[0122] The above control group is a superabsorbent resin composition that does not contain cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof.

[0123] In addition, the artificial urine inoculated with the above E. coli at 3000 CFU / ml is an artificial urine inoculated with the test microorganism Escherichia coli (E. coli, ATCC 25922) and contains odor components.

[0124] The adsorption tube experiment for evaluating the long-term deodorizing power described above will be explained in more detail in the experimental examples described later.

[0125]

[0126] (Method for manufacturing a superabsorbent resin composition)

[0127] According to one embodiment of the present invention, a method for manufacturing a superabsorbent resin composition is provided.

[0128] The method for manufacturing the superabsorbent resin composition comprises: a step of forming a hydrogel polymer by crosslinking an acrylic acid-based monomer having at least some neutralized acidic groups in the presence of an internal crosslinking agent (Step 1); a step of preparing a base resin comprising a crosslinked polymer obtained by drying and grinding the hydrogel polymer (Step 2); a step of preparing a surface crosslinking mixture by mixing the base resin and a surface crosslinking composition (Step 3); and a step of preparing a polyacrylic acid salt (based) resin having a surface crosslinking layer formed on the surface of the base resin by heat-treating the surface crosslinking mixture (Step 4); wherein cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof are each added independently in at least one of Step 3, Step 4, or after Step 4.

[0129]

[0130] The method for manufacturing the above superabsorbent resin composition can effectively control odors caused by various factors without lowering the basic physical properties of the superabsorbent resin, such as absorption capacity and water retention capacity, by using a combination of cucurbituril and ethylenediaminetetraacetic acid. All of the above-mentioned details can be applied equally to the above-mentioned cucurbituril and ethylenediaminetetraacetic acid.

[0131]

[0132] The present invention is described in detail below for each step.

[0133] (Step 1)

[0134] Step 1 above is a step of preparing a hydrogel polymer, specifically, a step of forming a hydrogel polymer by cross-linking a monomer composition comprising an acrylic acid-based monomer having at least some of neutralized acidic groups.

[0135]

[0136] The above acrylic acid-based monomer may be any monomer commonly used in the manufacture of superabsorbent resins. Specifically, the above acrylic acid-based monomer may be subject to all the aforementioned details.

[0137]

[0138] Meanwhile, the polymerization of the above monomer composition is carried out in the presence of an internal crosslinking agent to improve the physical properties of the resin produced by the polymerization of the acrylic acid-based monomer. The internal crosslinking agent may be applied in the same manner as described above.

[0139]

[0140] In addition, the monomer composition may include a polymerization initiator commonly used in the manufacture of superabsorbent resins.

[0141] As the polymerization initiator mentioned above, a thermal polymerization initiator or a photopolymerization initiator may be used depending on the polymerization method. However, even in the photopolymerization method, a certain amount of heat is generated by ultraviolet irradiation, and since a certain amount of heat is generated as the polymerization reaction, which is an exothermic reaction, proceeds, a thermal polymerization initiator may be additionally included.

[0142] As the above photopolymerization initiator, for example, one or more compounds selected from the group consisting of benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, benzyl dimethyl ketal, acyl phosphine, and α-aminoketone may be used. Among these, as a specific example of acyl phosphine, commercially available lucirin TPO, i.e., 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide, may be used. A wider variety of photopolymerization initiators are disclosed on page 115 of Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Application" (Elsevier, 2007), which can be referenced. Among the available photopolymerization initiators, commercially available product names include Igacure 819 (I-819).

[0143] One or more compounds selected from the group consisting of persulfate-based initiators, azo-based initiators, hydrogen peroxide, and ascorbic acid may be used as the thermal polymerization initiator. Specifically, examples of persulfate-based initiators include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8). In addition, azo-based initiators include 2,2-azobis-(2-amidinopropane) dihydrochloride, 2,2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride, 2-(carbamoylazo)isobutylonitril, 2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, and 4,4-azobis-(4-cyanovaleric Examples include acid (4,4-azobis-(4-cyanovaleric acid)). A wider variety of thermal polymerization initiators are disclosed on page 203 of Odian's book "Principles of Polymerization" (Wiley, 1981), which can be referenced.

[0144] Such polymerization initiators may be added to the monomer composition at a concentration of 0.001 to 1 weight% or 0.005 to 0.1 weight%. That is, if the concentration of the polymerization initiator is excessively low, the polymerization rate may be slowed down 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 excessively high, the polymer chains forming the network may become shorter, which may lead to a higher content of water-soluble components and a lower pressurized absorption capacity, thereby degrading the physical properties of the resin, which is undesirable.

[0145]

[0146] In addition, the cross-linking polymerization of the above monomer composition may be carried out in the presence of a blowing agent, depending on the necessity and extent of improving the absorption rate. This blowing agent decomposes during the cross-linking polymerization reaction process to generate gas, thereby forming pores within the hydrogel polymer. As a result, the additional use of this blowing agent forms a more developed porous structure within the superabsorbent resin, which can further improve the absorption rate of the superabsorbent resin.

[0147] As a non-limiting example, the blowing agent is sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, calcium bicarbonate, calcium carbonate, magnesium bicarbonate, magnesium carbonate, azodicarbonamide (ADCA), dinitrosopentamethylene tetramine (DPT), p,p'-oxybis(benzenesulfonyl hydrazide) (OBSH), p-toluenesulfonyl hydrazide (TSH), sucrose stearate, It may include one or more compounds selected from the group consisting of sucrose palmitate and sucrose laurate.

[0148] The foaming agent may be present in the monomer composition at a content of 1,000 to 4,000 ppmw, and more specifically, at a content of 1,000 ppm or more, or 1,100 ppmw or more, or 1,200 ppmw or more; and at a content of 4,000 ppmw or less, or 3,500 ppmw or less, or 3,000 ppmw or less.

[0149]

[0150] In addition, the above monomer composition may further include additives such as thickeners, plasticizers, preservation stabilizers, and antioxidants as needed.

[0151]

[0152] In addition, this monomer composition can be prepared in the form of a solution in which raw materials such as the aforementioned acrylic acid-based monomer, internal crosslinking agent, polymerization initiator, and foaming agent are dissolved in a solvent.

[0153]

[0154] The solvent that can be used at this time may be any solvent capable of dissolving the aforementioned raw materials, without any limitation in composition. 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.

[0155]

[0156] The formation of a hydrogel polymer through the polymerization of the above monomer composition can be carried out by conventional polymerization methods, and the process is not particularly limited.

[0157] As a non-limiting example, the polymerization method described above is broadly divided into thermal polymerization and photopolymerization depending on the type of polymerization energy source. Thermal polymerization can be carried out in a reactor equipped with a stirring shaft, such as a kneader, and photopolymerization can be carried out in a reactor equipped with a movable conveyor belt.

[0158] For example, a hydrogel polymer can be obtained by introducing the monomer composition into a reactor, such as a kneader equipped with a stirring shaft, and then supplying hot air or heating the reactor to perform thermal polymerization. At this time, depending on the shape of the stirring shaft equipped in the reactor, the hydrogel polymer discharged through the reactor outlet can be obtained as particles ranging from several millimeters to several centimeters. Specifically, the hydrogel polymer obtained can be obtained in various forms depending on the concentration and injection speed of the injected monomer composition, and typically, a hydrogel polymer with a (weight average) particle size of 2 to 50 mm can be obtained.

[0159] In addition, as another example, when photopolymerization of the monomer composition is carried out in a reactor equipped with a movable conveyor belt, a sheet-shaped hydrogel polymer can be obtained. In this case, the thickness of the sheet may vary depending on the concentration and injection speed of the injected monomer composition, but in order to ensure that the entire sheet is polymerized evenly while also securing the production speed, it is generally preferable to adjust the thickness to 0.5 to 10 cm.

[0160]

[0161] The hydrogel polymer formed by this method may exhibit a water content of 40 to 80 weight percent. Here, the water content is the weight of water in the total weight of the hydrogel polymer, and may be the value obtained 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 water evaporation in the polymer during the drying process in which the temperature of the polymer is raised through infrared heating. At this time, the drying conditions may be set such that the temperature is raised from room temperature to approximately 180°C and then maintained at 180°C, and the total drying time may be set to 20 minutes, including a 5-minute temperature raising step.

[0162]

[0163] (Step 2)

[0164] Step 2 above is a step of preparing a base resin by drying and grinding the hydrogel polymer prepared in Step 1 above.

[0165]

[0166] Specifically, in the above steps, not only is the drying efficiency of the hydrogel polymer increased, but the morphology of the superabsorbent resin is also affected, thereby influencing various physical properties of the superabsorbent resin, including the absorption rate. In particular, to improve the absorption rate of the superabsorbent resin, the present invention may further include a step of coarsely grinding the hydrogel polymer before drying. To distinguish it from grinding after drying, the term "coarse grinding" is used for convenience in this specification regarding grinding before drying.

[0167]

[0168] The grinder used for the above grinding is not limited in its configuration, but specifically, it may include any one selected from the group of grinding machines 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 examples described above.

[0169] At this time, the coarse grinding step can be performed so that the particle size of the hydrogel polymer is approximately 2 mm to approximately 10 mm. Grinding to a particle size of less than 2 mm is not technically easy due to the high water content of the hydrogel polymer, and aggregation may occur between the ground particles. On the other hand, if the particle size is ground to more than 10 mm, the effect of increasing the efficiency of the subsequent drying step may be negligible.

[0170]

[0171] The above drying may be performed at a temperature of 120 to 250°C, 140 to 200°C, or 150 to 190°C. In this case, the drying temperature may be defined as the temperature of the heat medium supplied for drying or the temperature inside the drying reactor containing the heat medium and the polymer during the drying process. Since process efficiency decreases if the drying temperature is low and the drying time is prolonged, it is preferable that the drying temperature be 120°C or higher to prevent this. Additionally, if the drying temperature is higher than necessary, the surface of the hydrogel polymer may dry excessively, which may lead to an increase in fine powder generation during the subsequent grinding stage and a deterioration in the physical properties of the final resin; to prevent this, it is preferable that the drying temperature be 250°C or lower.

[0172] At this time, the drying time in the above drying step is not particularly limited, but can be adjusted to 20 minutes to 90 minutes under the above drying temperature, taking into account process efficiency and the physical properties of the resin.

[0173] The above drying can be carried out using a conventional medium, for example, by methods such as supplying hot air to the pulverized hydrogel polymer, infrared irradiation, microwave irradiation, or ultraviolet irradiation.

[0174] In addition, it is preferable that this drying be performed so that the dried polymer has a moisture content of 0.1 to 10 weight%. That is, if the moisture content of the dried polymer is less than 0.1 weight%, it is undesirable as it may lead to increased manufacturing costs due to excessive drying and degradation of the cross-linked polymer. In addition, if the moisture content of the dried polymer exceeds 10 weight%, it is undesirable as defects may occur in subsequent processes.

[0175]

[0176] Next, the dried hydrogel polymer can be ground. This is a step for optimizing the surface area of ​​the base resin and the superabsorbent resin. The grinding can be performed so that the particle size of the ground polymer is 150 to 850 μm.

[0177] Conventional grinders such as pin mills, hammer mills, screw mills, roll mills, disc mills, and jog mills can be used at this time.

[0178]

[0179] In addition, to control the physical properties of the superabsorbent resin that is finalized into a product, a step of selectively classifying particles having a particle size of 150 to 850 μm from the polymer particles obtained through the grinding step can be performed.

[0180] A base resin can be obtained by going through the above classification steps. This base resin may have a particle size of 150 to 850 μm and may contain 2 weight% or less, or 1 weight% or less, of fine powder having a particle size of less than 150 μm.

[0181]

[0182] (Steps 3 and 4: Surface crosslinking step)

[0183] Next, the method comprises the step of preparing a surface crosslinking mixture by mixing the base resin and the surface crosslinking composition (Step 3); and the step of preparing a polyacrylate (based) resin in which a surface crosslinking layer is formed on a portion of the surface of the base resin by heat-treating the surface crosslinking mixture (Step 4).

[0184] The above surface crosslinking step induces a crosslinking reaction on the surface of the base resin in the presence of a surface crosslinking composition containing a surface crosslinking agent. The unsaturated bonds of water-soluble ethylene-based unsaturated monomers that remained on the surface without being crosslinked are crosslinked by the surface crosslinking agent, thereby forming a polyacrylate (based) resin with a high surface crosslinking density. Specifically, a surface crosslinking layer can be formed by a heat treatment process in the presence of a surface crosslinking agent. In this heat treatment process, the surface crosslinking density, i.e., the external crosslinking density, increases, while the internal crosslinking density remains unchanged. Consequently, the superabsorbent resin with the manufactured surface crosslinking layer has a structure in which the external crosslinking density is higher than the internal one.

[0185] Here, cucurbituril and ethylenediaminetetraacetic acid or salts thereof are each independently added in at least one of step 3 (=before the surface crosslinking step), step 4 (=during the surface crosslinking step), or after step 4 (=after the surface crosslinking step), so that the corresponding components are included in at least one of the interior or surface of the surface crosslinking layer.

[0186]

[0187] First, in the step (step 3) of preparing a surface crosslinking mixture by mixing a surface crosslinking composition with the base resin, the surface crosslinking composition includes a surface crosslinking agent for surface crosslinking, and the components and content of the surface crosslinking agent included in the surface crosslinking composition may be applied in the same manner as described above.

[0188] The above surface crosslinking composition includes water and / or a hydrophilic organic solvent as a medium, which has the advantage of allowing the surface crosslinking agent, etc., to be evenly dispersed on the base resin particles. At this time, the content of water and the hydrophilic organic solvent can be applied by adjusting the addition ratio per 100 parts by weight of base resin particles for the purpose of inducing even dissolution / dispersion of the surface crosslinking agent, preventing clumping of the base resin particles, and optimizing the surface penetration depth of the surface crosslinking agent.

[0189] Meanwhile, the surface crosslinking composition may additionally include an inorganic material to perform the step of forming a surface crosslinking layer. As such inorganic material, one or more inorganic materials selected from the group consisting of silica, clay, alumina, silica-alumina composites, titania, zinc oxide, and aluminum sulfate may be used. The inorganic material may be used in powder or liquid form, and in particular, may be used as alumina powder, silica-alumina powder, titania powder, or a nano-silica solution. Additionally, the inorganic material may be used in an amount of about 0.001 to about 1 part by weight per 100 parts by weight of base resin.

[0190] In addition, the surface crosslinking composition may further include a thickener. By further crosslinking the surface of the base resin powder in the presence of a thickener, the degradation of physical properties can be minimized even after grinding. Specifically, one or more selected from polysaccharides and hydroxy-containing polymers may be used as the thickener. Gum-based thickeners and cellulose-based thickeners may be used as the polysaccharides. Specific examples of the above-mentioned gum-based thickeners include xanthan gum, arabic gum, karaya gum, tragacanth gum, ghatti gum, guar gum, locust bean gum, and psyllium seed gum, and specific examples of the above-mentioned cellulose-based thickeners include hydroxypropylmethylcellulose, carboxymethylcellulose, methylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxymethylpropylcellulose, hydroxyethylhydroxypropylcellulose, ethylhydroxyethylcellulose, and methylhydroxypropylcellulose. Meanwhile, specific examples of the above-mentioned hydroxyl-containing polymers include polyethylene glycol and polyvinyl alcohol.

[0191]

[0192] The above surface crosslinking composition is prepared as a surface crosslinking mixture by mixing with a base resin, and there are no specific limitations on the mixing method.

[0193] For example, methods such as placing the surface crosslinking composition and the base resin into a reaction vessel and mixing them, spraying the surface crosslinking agent composition onto the base resin, or continuously supplying the base resin and the surface crosslinking agent composition to a continuously operated mixer and mixing them can be used.

[0194] At this time, the surface crosslinking composition may be a solution, and if the content of solids in the solution is 1% or more by weight, 3% or more by weight, 5% or more by weight, 10% or more by weight, or 50% or less by weight, 30% or less by weight, or 20% or less by weight, it is suitable for evenly dispersing in the base resin and at the same time can prevent clumping of the base resin.

[0195]

[0196] Next, the method includes the step (step 4) of heat-treating the surface crosslinking mixture to produce a polyacrylate (based) resin in which a surface crosslinking layer is formed on a portion of the surface of the base resin.

[0197] The above step involves heat-treating the base resin and the surface crosslinking composition to form an interpenetrating polymer network on the surface of the crosslinking polymer contained in the base resin, thereby further improving the physical properties of the superabsorbent resin. Through this surface modification, a surface crosslinking layer is formed on the surface of the pulverized base resin particles.

[0198] The step of forming the surface crosslinking layer can be carried out by heat treating at a temperature of 80°C to 250°C, 100°C to 200°C, or 110°C to 150°C for at least 30 minutes. More specifically, the surface crosslinking reaction can be carried out by heat treating at the maximum reaction temperature, with the above-mentioned temperature as the maximum reaction temperature, for 30 to 80 minutes, or 40 to 70 minutes.

[0199] By satisfying these surface crosslinking process conditions (in particular, temperature increase conditions and reaction conditions at the maximum reaction temperature), a superabsorbent resin that appropriately satisfies physical properties such as superior pressurized liquid permeability can be manufactured.

[0200] The means for raising the temperature for the surface crosslinking reaction are not particularly limited. Heating can be achieved by supplying a heat medium or by directly supplying a heat source. In this case, types of heat mediums that can be used include heated fluids such as steam, hot air, and hot oil, but are not limited thereto. Furthermore, the temperature of the supplied heat medium can be appropriately selected considering the medium type, the heating rate, and the target temperature. Meanwhile, directly supplied heat sources include heating via electricity and heating via gas, but are not limited to the examples described above.

[0201]

[0202] (Step 5)

[0203] Next, cucurbituril and ethylenediaminetetraacetic acid or a salt thereof are added, wherein each of the two components may be added independently in at least one of step 3, step 4, or step 4 or later. Here, the cucurbituril and ethylenediaminetetraacetic acid may be applied in the same manner as described above.

[0204]

[0205] According to one embodiment of the invention, the cucurbituril and ethylenediaminetetraacetic acid (or salt thereof) may each be added independently, separately, simultaneously, or sequentially. Specifically, they may each be added separately, simultaneously, or sequentially in at least one of step 3, step 4, or step after 4, and preferably, they may be added simultaneously or sequentially. Additionally, each component may be added in two or more divided steps at the same or different steps. When each component is added in divided steps, their content is calculated based on the mixed content.

[0206]

[0207] According to one embodiment of the invention, in the step of preparing the surface crosslinking mixture (step 3), cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof) may be additionally included, and accordingly, one or more of the two components are included inside and / or on the surface crosslinking layer. The above-described details may apply equally to the components and content of the cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof).

[0208]

[0209] According to one embodiment of the invention, in the step of forming a surface cross-linked layer by heat treatment (step 4), cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof) may be additionally included, and accordingly, one or more of the two components are included inside and / or on the surface cross-linked layer. The above-described details may apply equally to the components and content of the cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof).

[0210]

[0211] According to one embodiment of the invention, after the step of forming a surface cross-linked layer by heat treatment (step 4), cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof) may be additionally included, and accordingly, one or more of the two components are included on the surface of the cross-linked layer. The above-described details may apply equally to the components and content of the cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof).

[0212] The process following the step of forming a surface cross-linked layer by the above heat treatment (step 4) is not particularly limited, but may be performed together with post-treatment processes commonly applied in the field, such as a cooling process, a water process, and an additive addition process, but is not limited thereto.

[0213]

[0214] According to one embodiment of the invention, at least one step after the step of manufacturing the surface crosslinking mixture (step 3), the step of forming the surface crosslinking layer by heat treatment (step 4), or the step of forming the surface crosslinking layer by heat treatment (step 4) may additionally include cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof), and accordingly, one or more of said cucurbituril or ethylenediaminetetraacetic acid (or a salt thereof) are included in the interior and / or surface of the surface crosslinking layer.

[0215]

[0216] According to one embodiment of the invention, the cucurbituril and ethylenediaminetetraacetic acid (or salt thereof) may each be added independently in the aforementioned step in a manner of dry mixing or wet mixing, but are not limited thereto.

[0217] The above dry mixing method is not particularly limited and can be performed using a conventional mixing device. For example, it can be performed by hand mixing or using a plowshare mixer.

[0218] In addition, the conditions of the above dry mixing process can be appropriately determined for homogeneous mixing. For example, when using the above-mentioned plowshare mixer, it can be performed for 1 to 10 minutes, more specifically 3 to 5 minutes, at a stirring speed of 300 to 700 rpm, more specifically 450 to 550 rpm. When performed under the above conditions, the homogeneous mixing efficiency can be increased without breaking the superabsorbent resin particles, and the desired deodorizing and deodorizing effects can be uniformly exhibited.

[0219] The above wet mixing method is not particularly limited, but can be performed in the form of an aqueous solution, and can be performed by spraying to achieve a homogeneous thickness.

[0220] The above spraying process can be performed under temperature conditions of 50 to 90°C. When performed within the above temperature range, homogeneous mixing is possible without deterioration of the physical properties of the superabsorbent resin. If the temperature is below 50°C, there is a concern that processability may be reduced, and if it exceeds 90°C, there is a concern that mixing efficiency may be reduced because it is difficult to uniformly apply the hydrolysate solution as the rate of water evaporation increases. More specifically, it can be performed at 60 to 80°C.

[0221]

[0222] The operation and effects of the invention will be described in more detail below through specific embodiments. However, these embodiments are merely examples of the invention and do not define the scope of the invention.

[0223]

[0224] Examples and Comparative Examples: Preparation of Superabsorbent Resin

[0225] Example 1

[0226] (Step 1) 100 g of acrylic acid, 0.25 g of PEG400 as a crosslinking agent, 0.18 g of sodium persulfate (SPS) as a thermal initiator, 0.009 g of I-819 as a UV initiator, 140 g of caustic soda (NaOH), and 46 g of water were mixed to prepare an aqueous monomer solution composition having a monomer concentration of 43 wt%. The above aqueous monomer solution composition was fed into the feed section of a polymerization reactor equipped with a continuously moving conveyor belt, and ultraviolet light was irradiated using a UV irradiation device while maintaining the polymerization atmosphere temperature at 80°C (irradiation dose: 10 mW / cm²). 2 A hydrogel polymer was prepared by carrying out UV polymerization for 3 minutes.

[0227] (Step 2) The above hydrogel polymer was transferred to a meat chopper and cut into 16 mm pieces. Then, the hydrogel polymer was dried in a hot air dryer at a temperature of 170°C for 30 minutes, and the dried hydrogel polymer was ground using a pin mill grinder. Subsequently, the polymer with a particle size of 150 μm to 850 μm was classified using a sieve to produce a base resin.

[0228] (Step 3) Afterwards, a surface crosslinking solution (4.9 parts by weight of water, 0.11 parts by weight of ethylene glycol diglycidyl ether, 0.4 parts by weight of aluminum sulfate 18 hydrate (Al-S), and 0.1 parts by weight of silica (Aerosil A200)) was evenly mixed with 100 parts by weight of the base resin prepared above.

[0229] (Step 4) Next, the above mixture was subjected to a surface crosslinking reaction at 140°C for 40 minutes. After the surface treatment was completed, a polyacrylic acid salt (based) resin with an average particle size of 150 to 850 μm was obtained using a sieve. In the polyacrylic acid salt (based) resin obtained in this way, the content of particles with an average particle size of less than 150 μm was less than 2%.

[0230] (Step 5)

[0231] After the above surface crosslinking step, 1 part by weight of CB[6] (based on 100 parts by weight of polyacrylate salt(based) resin) was placed in a plastic bag and hand-mixed to ensure even mixing, and then put into a mixing mixer (KitchenAid mixer).

[0232] In another container, an aqueous solution of 0.5 parts by weight of EDTA (based on 100 parts by weight of polyacrylate salt (based) resin, based on dry weight) was prepared, and the above aqueous solution of EDTA was sprayed into a mixing mixer containing the absorbent resin and CB[6] while mixing under conditions of 60 rpm and 80°C to prepare a superabsorbent resin composition.

[0233]

[0234] Example 2

[0235] A superabsorbent resin composition was prepared under the same conditions as in Example 1, except that in step 5 of Example 1, CB[7] was used instead of CB[6], and the amount of EDTA was increased from 0.5 parts by weight to 1 part by weight.

[0236]

[0237] Example 3

[0238] A superabsorbent resin composition was prepared under the same conditions as in Example 1, except that in step 5 of Example 1, CB[8] was used instead of CB[6] and the amount of EDTA was increased from 0.5 parts by weight to 1 part by weight.

[0239]

[0240] Example 4

[0241] A superabsorbent resin composition was prepared under the same conditions as in Example 1, except that in step 5 of Example 1, 1 part by weight of CB[6] was increased to 2 parts by weight.

[0242]

[0243] Example 5

[0244] A superabsorbent resin composition was prepared under the same conditions as in Example 1, except that in Step 5 of Example 1, 0.5 parts by weight of EDTA was increased to 2 parts by weight.

[0245]

[0246] Comparative Example 1

[0247] A superabsorbent resin composition was prepared under the same conditions as in Example 1, except that in step 5 of Example 1, CB[6] was not used and EDTA was increased from 0.5 parts by weight to 1 part by weight.

[0248]

[0249] Comparative Example 2

[0250] A superabsorbent resin composition was prepared under the same conditions as in Example 1, except that in step 5 of Example 1, CB[6] was not used and EDTA was increased to 3 parts by weight and used instead of 0.5 parts by weight.

[0251]

[0252] Comparative Example 3

[0253] In step 5 of Example 1, a superabsorbent resin composition was prepared under the same conditions as Example 1, except that EDTA was not used.

[0254]

[0255] Comparative Example 4

[0256] In step 5 of Example 1, a superabsorbent resin composition was prepared under the same conditions as Example 1, except that CB[7] was used instead of CB[6] and EDTA was not used.

[0257]

[0258] Comparative Example 5

[0259] In step 5 of Example 1, a superabsorbent resin composition was prepared under the same conditions as Example 1, except that CB[8] was used instead of CB[6] and EDTA was not used.

[0260]

[0261] Experimental Example

[0262] For the superabsorbent resin compositions prepared in the above examples and comparative examples, each physical property was measured by the following method, and the results are shown in Table 1 below.

[0263]

[0264] (1) Evaluation of absorption properties

[0265] 1) Centrifuge Retention Capacity (CRC)

[0266] The water retention capacity of the superabsorbent resin compositions of the above examples and comparative examples was measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 241.3.

[0267] Specifically, from the superabsorbent resin compositions obtained through the examples and comparative examples, a resin classified by a #30-50 sieve was obtained. This resin W0 (g) (about 0.2g) was uniformly placed into a nonwoven bag and sealed, then immersed in physiological saline solution (0.9 wt%) at room temperature. After 30 minutes, the water was drained from the bag for 3 minutes under conditions of 250g using a centrifuge, and the mass W2 (g) of the bag was measured. In addition, the same operation was performed without using the resin, and the mass W1 (g) was measured.

[0268] Using each mass obtained, the CRC(g / g) was calculated according to the following formula 1.

[0269] [Formula 1]

[0270] CRC (g / g) = {[W2(g) - W1(g)] / W0(g)} - 1

[0271]

[0272] 2) Absorbency under Pressure (AUP)

[0273] The pressurized absorption capacity of the superabsorbent resin compositions of the above examples and comparative examples at 0.7 psi was measured according to the EDANA method WSP 242.3.

[0274] First, when measuring pressurized absorption capacity, the resin classifier from the above CRC measurement was used.

[0275] Specifically, a stainless steel 400 mesh wire mesh was mounted on the bottom of a plastic cylinder with an inner diameter of 25 mm. Under conditions of room temperature and 50% humidity, a superabsorbent resin W0 (g) was uniformly spread over the wire mesh, and a piston capable of uniformly applying a load of 0.7 psi was positioned so that its outer diameter was slightly smaller than 25 mm, there was no gap with the inner wall of the cylinder, and its vertical movement was not obstructed. At this time, the weight W3 (g) of the device was measured.

[0276] A glass filter with a diameter of 90 mm and a thickness of 5 mm was placed on the inside of a petroleum dish with a diameter of 150 mm, and physiological saline solution composed of 0.9 wt% sodium chloride was placed at the same level as 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 the filter paper, and the liquid was absorbed under load for 1 hour. After 1 hour, the measuring device was lifted, and its weight W4 (g) was measured. Using each obtained mass, the pressurized absorption capacity (g / g) was calculated according to the following formula 2.

[0277] [Formula 2]

[0278] AUP(g / g) = [W4(g) - W3(g)] / W0(g)

[0279]

[0280] 3) Gel Bed Permeability (GBP, darcy)

[0281] For the superabsorbent resin compositions of the above examples and comparative examples, the free swelling gel bed permeability to physiological saline was measured, and the results are shown in Table 1 below.

[0282] The above gel bed permeability is the same as the method described in Korean Patent Application No. 10-2014-7018005 (using the same device) and was measured according to the following formula 3.

[0283] [Formula 3]

[0284] K = [Q×H×Mu] / [A×Rho×P]

[0285] Among the above formulas,

[0286] K is the permeability (cm²), Q is the flow velocity (g / velocity), and,

[0287] H is the height of the sample (cm), Mu is the liquid viscosity (poise) (approximately 1 cps for the test solution used in the test), and

[0288] A is the cross-sectional area (cm²) for liquid flow, and

[0289] Rho is the liquid density (g / cm³) (for the test solution used in the test), and P is the hydrostatic pressure (dynes / cm²) (typically about 3,923 dynes / cm²).

[0290] Hydrostatic pressure is calculated using the following formula 3-1.

[0291] [Formula 3-1]

[0292] P = Rho × g × h

[0293] Among the above formulas,

[0294] Rho is the liquid density (g / cm³), and

[0295] g is the acceleration due to gravity, typically 981 cm / sec 2 is,

[0296] h is the fluid height (e.g., 7.8 cm in the case of the permeability test described herein).

[0297]

[0298] (2) Evaluation of odor reduction

[0299] 1) Evaluation of short-term odor reduction

[0300] A short-term odor reduction evaluation was performed on the superabsorbent resin compositions of the above examples and comparative examples using the following method. Here, the odor reduction evaluation is a measurement of the residual rate of odor substances relative to the control group, and the control group refers to the superabsorbent resin composition in which step 5 (addition of EDTA and cucurbituril) was not performed in Example 1.

[0301] First, an odor standard solution was prepared by sufficiently dissolving 2-methoxyphenol and p-cresol as odor substances in a 0.9 wt% NaCl solution at concentrations of 1.3 μg / mL to 2.5 μg / mL, respectively.

[0302] Next, 80 mg of the sample to be measured (Example, Comparative Example, Control Group) was placed in a 20 mL vial, and 2 mL of the odor standard solution was injected. The vial was sealed and maintained at a temperature of 35°C for approximately 2 hours. The injection of the odor standard solution and the maintenance at 35°C for 2 hours were performed using the PAL RTC automatic injection system from CTC. Using the Solid Phase Micro Extraction (SPME) Arrow (Carbon WR / PDMS Fiber) mounted on the PAL RTC automatic injection system, the odor standard substance was adsorbed for approximately 15 minutes at a temperature within the range of 30°C to 40°C, and the peak area of ​​the odor substance after adsorption was confirmed using a Gas Chromatography-Mass Spectrometer (GC-MS). The Agilent 8890 GC / 5977B MSD was used as the GC-MS system. The SPME Arrow mounted on the PAL RTC was injected into the Split / Splitless inlet, and a DB-624 Ultra Inert (UI) column was used. During measurement, He gas was used as the mobile phase, and the heater temperature at the sample inlet was set to around 250°C during injection to desorb the sample adsorbed on the SPME (Solid Phase Micro Extraction).

[0303] For each of the odor substances 2-methoxyphenol and p-cresol, the short-term residual rate of the odor substance relative to the control group was measured according to Calculator 3 below, and the results were listed in Table 1 below.

[0304] [Formula 3]

[0305] Short-term odor substance residue rate (%) = Cs / Co × 100

[0306] In the above formula,

[0307] Cs is the peak area of ​​the odor substance measured for the superabsorbent resin sample being measured, and

[0308] Co is the peak area of ​​the odor substance measured relative to the control group.

[0309]

[0310] 2) Long-term odor substance reduction evaluation

[0311] Long-term odor reduction evaluation was performed on the superabsorbent resin compositions of the above examples and comparative examples using the following method. Here, the odor reduction evaluation is a measurement of the residual rate of odor substances relative to the control group, and the control group refers to the superabsorbent resin composition in which step 5 (addition of EDTA and cucurbituril) was not performed in Example 1.

[0312] First, 1 g of the sample to be measured (Example, Comparative Example, Control Group) was placed in a 500 mL glass bottle, and then 25 mL of artificial urine inoculated with 3000 CFU / mL of E. coli was injected into the glass bottle. Subsequently, aging was performed for 24 hours in a constant temperature chamber, followed by collection for 20 minutes. At this time, the temperature of the constant temperature chamber was 35℃ and the N2 flow rate was 220 mL / min. The generated odor was then adsorbed onto a connected adsorption tube, and this process was repeated twice per sample to collect the odor. The peak area of ​​the collected odor substances was confirmed using Gas Chromatography-Mass Spectrometry (GC-MS).

[0313] A Tenax-GR adsorption tube was used, and the adsorption tube was fixed to the end of the glass bottle to allow odor molecules to be adsorbed.

[0314] For each of the odor substances 2-methoxyphenol and p-cresol, the long-term residual rate of the odor substance relative to the control group was measured according to Calculator 4 below, and the results were listed in Table 1 below.

[0315] [Formula 4]

[0316] Long-term odor substance residual rate (%) = Ts / To Х 100

[0317] In the above formula,

[0318] Ts is the peak area of ​​the odor substance measured for the superabsorbent resin sample being measured, and

[0319] To is the peak area of ​​the odor substance measured relative to the control group.

[0320]

[0321] Classification Short-term odor substance reduction (retention rate (%) compared to control group measured) Long-term odor substance reduction (retention rate (%) compared to control group measured) Absorption properties 2-Methoxyphenol p-Cresol 2-Methoxyphenol p-Cresol CRC (g / g) 0.9AUL (g / g) GBP(darcy) Control Group 100 100 100 100 36.0 18.14 Example 1 30 35 20 35.8 18.34 Example 2 25 31 20 35.6 18.35 Example 3 18 25 10 35.8 18.14 Example 4 40 45 45 0 36.1 18.25 Example 5 24 30 10 35.1 17.71 Comparative Example 19 59 810 36.2 17.65 Comparative Example 2100951034.617.52 Comparative Example 359759810036.017.63 Comparative Example 463659810036.317.94 Comparative Example 53861855035.818.04

[0322] As can be seen in the table above, it was confirmed that the examples can effectively reduce primary odors generated under actual usage conditions of the resin product and secondary odors generated due to bacterial growth during use of the product while maintaining excellent absorption properties.

Claims

1. Polyacrylate (based) resin; Cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof; comprising Superabsorbent resin composition.

2. In Paragraph 1, The above cucurbituril and ethylenediaminetetraacetic acid or a salt thereof are mixed in a weight ratio of 1:0.2 to 1 to 2, Superabsorbent resin composition.

3. In Paragraph 1, The above cucurbituril is one or more selected from the group consisting of CB[5], CB[6], CB[7] and CB[8], Superabsorbent resin composition.

4. In Paragraph 1, The above cucurbituril is included in an amount of 0.1 to 10 parts by weight per 100 parts by weight of polyacrylic acid salt (based) resin, Superabsorbent resin composition.

5. In Paragraph 1, The above ethylenediaminetetraacetic acid or its salt is included in an amount of 0.01 to 2 parts by weight per 100 parts by weight of polyacrylic acid salt(system) resin, Superabsorbent resin composition.

6. In Paragraph 1, The above polyacrylic acid salt(based) resin comprises a base resin comprising a crosslinked polymer in which an acrylic acid monomer having at least a portion of neutralized acidic groups is crosslinked with an internal crosslinking agent, and a surface crosslinking layer formed on the surface of the base resin, wherein the crosslinked polymer is further crosslinked via a surface crosslinking agent. The above cucurbituril and ethylenediaminetetraacetic acid or salt thereof are each independently included in at least one of the interior or surface of the surface cross-linked layer, Superabsorbent resin composition.

7. In Paragraph 1, A superabsorbent resin composition in which, after adding the above superabsorbent resin composition to an odor solution and storing it at 35±0.5℃ for 2 hours, the concentration of the odor component in the odor solution measured by solid-phase microextraction (SPME) satisfies the values ​​of 1) and 2) below compared to the control group: 1)C 1-6 The concentration of the alkoxyphenol compound is 50% or less, and 2)C 1-6 The concentration of the alkyl phenol compound is 50% or less, and Here, the above odor solution is C 1-6 Alkoxyphenol compounds and C 1-6 It is a mixed solution containing an alkyl phenolic compound, and The above control group is a superabsorbent resin composition that does not contain cucurbituril; and ethylenediaminetetraacetic acid or ethylenediaminetetraacetic acid or a salt thereof.

8. In Paragraph 1, A superabsorbent resin composition in which, after mixing the above superabsorbent resin composition with artificial urine inoculated with E. coli at 3000±300 CFU / ml and storing the mixed solution at 35±0.5℃ for 24 hours, the concentration of malodorous components in the mixed solution measured according to an adsorption tube experiment satisfies the values ​​of 1) and 2) below compared to the control group: 1)C 1-6 The concentration of the alkoxyphenol compound is less than 5%, and 2)C 1-6 The concentration of the alkyl phenol compound is 50% or less, and Here, the above mixed solution is C 1-6 Alkoxyphenol compounds and C 1-6 It contains malodorous components of alkyl phenolic compounds, and The above control group is a superabsorbent resin composition that does not contain cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof.

9. A step of forming a hydrogel polymer by crosslinking an acrylic acid-based monomer having at least some of neutralized acidic groups in the presence of an internal crosslinking agent (Step 1); A step of preparing a base resin comprising a cross-linked polymer obtained by drying and grinding the above-mentioned hydrogel polymer (Step 2); A step of preparing a surface crosslinking mixture by mixing the above base resin and the surface crosslinking composition (Step 3); and The method comprises the step (step 4) of heat-treating the surface crosslinking mixture to produce a polyacrylic acid salt (based) resin in which a surface crosslinking layer is formed on the surface of the base resin, and Cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof; each independently added in at least one of step 3, step 4, or after step 4, Method for manufacturing a superabsorbent resin composition.

10. In Paragraph 9, The above cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof; are each independently added as a dry mixture or a wet mixture, Method for manufacturing a superabsorbent resin composition.

11. In Paragraph 9, The above cucurbituril; and ethylenediaminetetraacetic acid or a salt thereof; are each added independently, simultaneously, or sequentially. Method for manufacturing a superabsorbent resin composition.

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