Super absorbent polymer and preparation method thereof

Abstract

The present invention relates to a superabsorbent resin and a method for manufacturing the same, and more specifically, provides a superabsorbent resin and a method for manufacturing the same that can exhibit improved bacterial growth inhibition properties without reducing the absorption performance of the superabsorbent resin.

Description

Technology Field

[0001] The present invention relates to a superabsorbent resin that exhibits enhanced bacterial growth inhibition properties without reducing the absorption performance of the superabsorbent resin, and a method for manufacturing the same. Background Technology

[0003] 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 in various fields, including sanitary products such as children's disposable diapers, soil conditioners for horticulture, waterproofing materials for civil engineering and construction, seedling sheets, freshness preservation agents in the food distribution sector, materials for compresses, and even in the field of electrical insulation.

[0005] In particular, superabsorbent polymers are most widely applied in hygiene products or disposable absorbent products, such as children's disposable diapers and adult diapers. Consequently, the proliferation of bacteria in these hygiene products and disposable absorbent products poses a problem, as it can cause various diseases as well as secondary odors. Therefore, there have been previous attempts to introduce various bacterial growth inhibitory components or deodorizing or antibacterial functional components into superabsorbent polymers.

[0007] However, when introducing antimicrobial agents that inhibit bacterial growth into superabsorbent resins in this manner, it was not easy to select and introduce an antimicrobial agent component that exhibits excellent bacterial growth inhibition and deodorizing properties, is harmless to the human body, satisfies economic feasibility, and does not degrade the basic physical properties of the superabsorbent resin.

[0009] Accordingly, there is a continuous demand for the development of superabsorbent resin-related technologies that can inhibit the growth of bacteria effectively without compromising the fundamental properties of the superabsorbent resin. The problem to be solved

[0011] Accordingly, the present invention aims to provide a superabsorbent resin capable of exhibiting enhanced bacterial growth inhibition properties without reducing the absorption performance of the superabsorbent resin, and a method for manufacturing the same. means of solving the problem

[0013] According to one embodiment of the present invention,

[0014] A superabsorbent resin is provided, comprising: an acrylic acid-based monomer having acidic groups, wherein at least a portion of the acidic groups are neutralized; a polymerizable antimicrobial monomer represented by the following chemical formula 1; and a crosslinking agent; and a crosslinked polymer.

[0015] [Chemical Formula 1]

[0016]

[0017] In the above chemical formula 1,

[0018] R1 to R3 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, or a carboxyl group (COOH), and

[0019] L is a single bond; or an arylene having 6 to 60 carbon atoms, and

[0020] A is an aromatic ring having 6 to 60 carbon atoms, and

[0021] Here, the arylene and aromatic rings are each independently unsubstituted or substituted with one or more substituents selected from the group consisting of hydroxyl, alkyl having 1 to 10 carbon atoms, and alkoxy having 1 to 10 carbon atoms.

[0023] According to another embodiment of the present invention,

[0024] A step of preparing a monomer composition by mixing an acrylic acid-based monomer containing an acidic group, a polymerizable antimicrobial monomer represented by Chemical Formula 1, a crosslinking agent, and a polymerization initiator (Step 1);

[0025] A step of polymerizing the above monomer composition to form a hydrogel polymer (Step 2); and

[0026] A method for manufacturing a superabsorbent resin is provided, comprising the step (step 3) of drying, grinding, and classifying the above-mentioned hydrogel polymer:

[0028] Furthermore, according to another embodiment of the present invention, an article comprising the above-described superabsorbent resin is provided. Effects of the invention

[0030] The superabsorbent resin of the present invention can exhibit antibacterial properties that inhibit the growth of bacteria that are harmful to the human body and can cause secondary odors.

[0032] Specifically, the superabsorbent resin is manufactured using a polymerizable antimicrobial monomer of a specific structure when forming a cross-linked polymer, thereby exhibiting antimicrobial properties against at least one of Gram-positive bacteria and Gram-negative bacteria, while maintaining excellent water retention capacity unlike when other antimicrobial agents are used.

[0034] In addition, since the polymerizable antimicrobial monomer is copolymerized with an acrylic acid monomer, the risk of leaching of the polymerizable antimicrobial monomer is reduced compared to when the polymerizable antimicrobial monomer or a polymer in which the polymerizable antimicrobial monomer is polymerized is simply mixed with a superabsorbent resin, so there is no risk of harm to human safety due to the leaching of the antimicrobial agent.

[0036] Therefore, the above-mentioned superabsorbent resin can be very advantageously applied to various hygiene products, such as children's diapers as well as adult diapers requiring antibacterial properties against bacteria. Brief explanation of the drawing

[0038] Figure 1 shows the polymerizable antimicrobial monomer 1-1. 1 This shows the H NMR spectrum. Specific details for implementing the invention

[0039] The terms used herein are merely for describing exemplary embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to indicate the presence 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.

[0040] Furthermore, in the present invention, when each layer or element is referred to as being formed "on" or "above" each layer or element, it means that each layer or element is formed directly on each layer or element, or that another layer or element may be additionally formed between each layer, on an object, or on a substrate.

[0041] 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.

[0042] Furthermore, the technical terms used in this specification are intended merely to refer to specific embodiments and are not intended to limit the invention. Also, the singular forms used herein include plural forms unless the phrases clearly indicate otherwise.

[0043] Meanwhile, the term "(meth)acrylate" as used in this specification includes both acrylate and methacrylate.

[0044] Additionally, in this specification, the alkyl group may be a straight chain or a branched chain, and while the number of carbon atoms is not particularly limited, it is preferably 1 to 20. According to one embodiment, the number of carbon atoms of the alkyl group is 1 to 10. According to another embodiment, the number of carbon atoms of the alkyl group is 1 to 6. Specific examples of the above alkyl groups include methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethylbutyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, 1-ethyl-propyl, 1,1-dimethylpropyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, heptyl, n-heptyl, 1-methylhexyl, 2-methylhexyl, 3-methylhexyl, 4-methylhexyl, 5-methylhexyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2,4,4-trimethyl-1-pentyl, Examples include 2,4,4-trimethyl-2-pentyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, but are not limited thereto. Additionally, in this specification, the description of the alkyl group described above may apply except that the alkylene is a divalent group.

[0045] In addition, in this specification, the alkoxy group may be a straight chain or a branched chain, and the number of carbon atoms is not particularly limited, but is preferably 1 to 10. According to another embodiment, the number of carbon atoms of the alkoxy group is 1 to 6. Specific examples of the alkoxy group include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, etc., but are not limited thereto.

[0046] In addition, in this specification, the aryl group is not particularly limited, but preferably has 6 to 60 carbon atoms and may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the number of carbon atoms of the aryl group is 6 to 30. According to one embodiment, the number of carbon atoms of the aryl group is 6 to 20. As a monocyclic aryl group, the aryl group may be a phenyl group, a biphenyl group, a terphenyl group, etc., but is not limited thereto. As a polycyclic aryl group, the aryl group may be a naphthyl group, anthryl group, a phenanthryl group, a pyrenyl group, a perylenyl group, a chrysenyl group, a fluorenyl group, etc., but is not limited thereto. In addition, in this specification, the description of the aryl group described above may apply except that the arylene is a divalent group.

[0047] In addition, in this specification, an aromatic ring refers to a monocyclic or condensed polycyclic ring in which the entire molecule has aromaticity and contains only carbon as a ring-forming atom. The number of carbon atoms in the aromatic ring is 6 to 60, or 6 to 30, or 6 to 20, but is not limited thereto. In addition, the aromatic ring may be a benzene ring, a naphthalene ring, anthracene ring, a phenanthrene ring, a pyrene ring, etc., but is not limited thereto.

[0048] The terms "polymer" or "polymer" used in the specification of the present invention refer to a state in which acrylic acid 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 polymer may be referred to as a cross-linked polymer.

[0049] Additionally, the term "superabsorbent resin particles" refers to a particulate material comprising a cross-linked polymer in which an acrylic acid-based monomer containing an acidic group and at least a portion of said acidic group is neutralized is polymerized and cross-linked by an internal cross-linking agent.

[0050] Additionally, depending on the context, the term "superabsorbent resin" is used to encompass a cross-linked polymer formed by polymerizing an acrylic acid-based monomer containing acidic groups and having at least some of said acidic groups neutralized, or a base resin in powder form consisting of superabsorbent resin particles formed by grinding said cross-linked polymer, or a state suitable for commercialization obtained by subjecting said cross-linked polymer or said base resin to additional processes, such as surface cross-linking, fine powder reassembly, drying, grinding, classification, etc.

[0052] Conventionally, to secure antibacterial and deodorizing properties in superabsorbent polymers, metal compounds with antibacterial functions or organic compounds containing cationic or alcohol functional groups were introduced as additives. However, in this case, the safety of the superabsorbent polymer was compromised, basic physical properties such as absorption characteristics were degraded, and there were also issues regarding the sustainability of antibacterial properties and the leakage of antibacterial substances.

[0054] For example, attempts have been made to introduce antimicrobial agents containing antimicrobial metal ions, such as silver, copper, and zinc, into superabsorbent polymers. These antimicrobial metal ion-containing components can impart deodorizing properties to the superabsorbent polymer by destroying the cell walls of microorganisms, such as bacteria, and killing bacteria that possess enzymes capable of causing odors. However, the above-mentioned metal ion-containing components are classified as biocides, which can kill even microorganisms beneficial to the human body. Consequently, when the above-mentioned superabsorbent polymer is applied to hygiene products such as children's or adult diapers, the introduction of the above-mentioned metal ion-containing antimicrobial agents is largely excluded.

[0056] Furthermore, conventionally, when introducing antimicrobial agents that inhibit bacterial growth into superabsorbent polymers, a method of mixing a small amount of the antimicrobial agent into the polymer was primarily applied. However, it is true that when applying this mixing method, it was difficult to maintain uniform bacterial growth inhibition properties over time. Moreover, this mixing method had disadvantages, such as the potential for uneven application and detachment of the antimicrobial agent components during the mixing process, as well as the need to install new equipment for the mixing process.

[0058] Furthermore, there is a vast diversity of bacteria, with over 5,000 identified species alone. Specifically, bacteria exhibit diverse cell shapes, such as spherical, rod-shaped, or spiral, and their oxygen requirements vary, leading to their classification into aerobic, facultative, and anaerobic bacteria. Consequently, it has typically been difficult for a single type of antimicrobial agent to possess the physical or chemical mechanisms necessary to damage the cell membranes or walls of various bacteria or to denature their proteins.

[0060] However, the present invention was completed by confirming that when a superabsorbent resin is prepared by polymerizing a monomer containing a hydroxyl group (OH) having a specific structure together with an acrylic acid-based monomer, it can exhibit an absorption performance of a certain level or higher while also exhibiting antibacterial activity against at least one of Gram-positive bacteria and Gram-negative bacteria.

[0062] Specifically, when the polymerizable antimicrobial monomer represented by Chemical Formula 1 comes into contact with bacteria, the aromatic ring structure substituted with a hydroxyl group may bind to a protein substance essential for the metabolic activity of the bacteria, thereby inhibiting the growth of the bacteria. More specifically, the hydroxyl group may reduce the metabolic activity of the bacteria through a reaction with a thiol group (sulfhydryl group, -SH) that may be present in the bacterial protein or through non-binding interactions with other protein parts, and thereby inhibit the growth of the bacteria. Accordingly, a superabsorbent resin comprising a cross-linked polymer formed by the polymerizable antimicrobial monomer represented by Chemical Formula 1 may exhibit antimicrobial activity against at least one of Gram-positive bacteria and Gram-negative bacteria.

[0064] Furthermore, since the superabsorbent resin contains the antimicrobial monomer in the form of a cross-linked polymer cross-linked with an acrylic acid-based monomer, the antimicrobial monomer does not remain in the form of a compound within the superabsorbent resin, so there is no concern that the antimicrobial agent will leach out over time, and thus it has the characteristic of exhibiting excellent stability.

[0066] Hereinafter, a superabsorbent resin and a method for manufacturing the same will be described in more detail according to specific embodiments of the invention.

[0068] Superabsorbent resin

[0069] Specifically, a superabsorbent resin according to one embodiment of the invention is characterized by comprising: an acrylic acid-based monomer having acidic groups and at least a portion of said acidic groups neutralized; a polymerizable antimicrobial monomer represented by the following chemical formula 1; and a crosslinking agent; a crosslinked polymer of which:

[0070] [Chemical Formula 1]

[0071]

[0072] In the above chemical formula 1,

[0073] R1 to R3 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, or a carboxyl group (COOH), and

[0074] L is a single bond; or an arylene having 6 to 60 carbon atoms, and

[0075] A is an aromatic ring having 6 to 60 carbon atoms, and

[0076] Here, the arylene and aromatic rings are each independently unsubstituted or substituted with one or more, for example, one to five, substituents selected from the group consisting of hydroxyl, alkyl having 1 to 10 carbon atoms, and alkoxy having 1 to 10 carbon atoms.

[0078] At this time, the crosslinked polymer is formed by crosslinking the acrylic acid-based monomer and the polymerizable antimicrobial monomer in the presence of a crosslinking agent, and has a three-dimensional network structure in which the main chains formed by the polymerization of the monomers are crosslinked by the crosslinking agent. Therefore, since the polymerizable antimicrobial monomer does not exist as a separate compound within the superabsorbent resin but exists as a repeating unit constituting the main chain, it does not leak out over time, so the antimicrobial properties of the superabsorbent resin can be continuously maintained.

[0080] In addition, the centrifugal retention capacity can be improved by further including repeating units induced by polymerizable antimicrobial monomers in addition to repeating units induced by acrylic acid-based monomers in the cross-linked polymer of the superabsorbent resin.

[0082] Meanwhile, in the above chemical formula 1, R1 to R3 may each independently be hydrogen, methyl, or a carboxyl group.

[0084] For example, R1 to R3 may all be hydrogen; or one of R1 to R3 may be methyl or a carboxyl group, and the rest may be hydrogen.

[0086] In addition, in the above formula 1, L may be a single bond; or an arylene having 6 to 20 carbon atoms that is unsubstituted or substituted with 1 to 3 substituents selected from the group consisting of hydroxyl, alkyl having 1 to 10 carbon atoms, and alkoxy having 1 to 10 carbon atoms.

[0088] Specifically, L can be a single bond, phenylene, or naphthylene.

[0090] For example, L may be any one selected from the group consisting of a single bond or, but is not limited thereto:

[0091] .

[0093] In addition, in the above formula 1, A may be an aromatic ring having 6 to 20 carbon atoms that is unsubstituted or substituted with 1 to 3 substituents selected from the group consisting of hydroxyl, alkyl having 1 to 10 carbon atoms, and alkoxy having 1 to 10 carbon atoms.

[0095] More specifically, A is a benzene or naphthalene ring, and

[0096] Here, the benzene and naphthalene rings may each be independently unsubstituted or substituted with one to three substituents selected from the group consisting of hydroxyl, alkyl having 1 to 10 carbon atoms, and alkoxy having 1 to 10 carbon atoms.

[0098] For example, A is a benzene or naphthalene ring, and

[0099] Here, the benzene and naphthalene rings may each be independently unsubstituted or substituted with one to three substituents selected from the group consisting of hydroxy, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl, n-pentyl, n-hexyl, n-heptyl, n-octyl, 2,4,4-trimethyl-1-pentyl, 2,4,4-trimethyl-2-pentyl, methoxy, ethoxy, n-propoxy, and n-butoxy.

[0101] The above polymerizable antimicrobial monomer may be represented by any one of the following chemical formulas 1-1 to 1-3:

[0102] [Chemical Formula 1-1]

[0103]

[0104] [Chemical Formula 1-2]

[0105]

[0106] [Chemical Formula 1-3]

[0107]

[0108] In the above chemical formulas 1-1 to 1-3,

[0109] L' is a single bond, phenylene, or naphthylene, and

[0110] R is a hydroxyl, an alkyl having 1 to 10 carbon atoms, or an alkoxy having 1 to 10 carbon atoms, and

[0111] a is an integer from 0 to 3, and

[0112] If a is 2 or greater, two or more Rs are identical or different from each other, and

[0113] R1 to R3 are as defined in Chemical Formula 1 above.

[0115] In the above chemical formulas 1-1 to 1-3, L may be a single bond, 1,4-phenylene, 1,3-phenylene, or 1,6-naphthylene, but is not limited thereto.

[0117] In addition, in the above chemical formulas 1-1 to 1-3, a can be 0, 1, 2, or 3.

[0119] For example, the polymerizable antimicrobial monomer may be any one selected from the group consisting of the following, but is not limited thereto:

[0122]

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132] .

[0134] Furthermore, the polymerizable antimicrobial monomer is included in the cross-linked polymer in an amount of 0.1 to 1 part by weight relative to 100 parts by weight of the acrylic acid-based monomer. If the polymerizable antimicrobial monomer is included in an amount of less than 0.1 part by weight relative to 100 parts by weight of the acrylic acid-based monomer, it is difficult to exhibit a sufficient antimicrobial effect. If the polymerizable antimicrobial monomer is included in an amount of more than 1 part by weight relative to 100 parts by weight of the acrylic acid-based monomer, the radical polymerization reaction may be delayed due to the hydroxyl groups (OH) contained in the polymerizable antimicrobial monomer. Consequently, there is a concern that the polymerization may not be sufficiently carried out or the polymerization time may be prolonged, as the polymerization ability may be reduced during the polymerization of the acrylic acid-based monomer.

[0136] More specifically, the polymerizable antimicrobial monomer may be included in the cross-linked polymer in an amount of 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more, and 1 part by weight or less, relative to 100 parts by weight of the acrylic acid-based monomer. In this case, in terms of improving the antimicrobial properties and absorption performance of the superabsorbent resin, it is preferable that the polymerizable antimicrobial monomer be included in the cross-linked polymer in an amount of 0.2 to 1 part by weight relative to 100 parts by weight of the acrylic acid-based monomer.

[0138] At this time, the meaning that the polymerizable antimicrobial monomer is included in the cross-linked polymer in an amount of 0.1 to 1 weight part per 100 weight parts of the acrylic acid-based monomer means that the polymerizable antimicrobial monomer is used in an amount of 0.1 to 1 weight part per 100 weight parts of the acrylic acid-based monomer when manufacturing the cross-linked polymer. This can be confirmed by checking whether the antimicrobial monomer is detected when verifying the residual monomer of the superabsorbent resin, and since no antimicrobial monomer is detected after manufacturing the superabsorbent resin, it can be considered that the entire amount of antimicrobial monomer used was used for polymerization with the acrylic acid-based monomer.

[0140] Meanwhile, the above acrylic acid-based monomer is a compound represented by the following chemical formula 2:

[0141] [Chemical Formula 2]

[0142] R-COOM'

[0143] In the above chemical formula 2,

[0144] R is an alkenyl group having 2 to 5 carbon atoms containing an unsaturated bond, and

[0145] M' is a hydrogen atom, a monovalent or divalent metal, an ammonium group, or an organic amine salt.

[0146] Preferably, the monomer may be one or more selected from the group consisting of (meth)acrylic acid and monovalent (alkali) metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids.

[0147] As such, using (meth)acrylic acid and / or its salts as acrylic acid-based monomers is advantageous because it allows for obtaining a superabsorbent resin with improved absorption.

[0149] In addition, the term 'crosslinking agent' used in this specification is used to distinguish it from the additional crosslinking agent described below, which is intended to primarily crosslink the surface of the superabsorbent resin particles. It serves to crosslink the unsaturated bonds of the aforementioned acrylic acid-based monomers and polymerizable antimicrobial monomers to polymerize them. Although the crosslinking in the above step proceeds without distinction between the surface and the interior, when the additional crosslinking process of the superabsorbent resin particles described below is carried out, the surface of the finally manufactured superabsorbent resin particles consists of a structure primarily crosslinked by the additional crosslinking agent, and the interior consists of a structure primarily crosslinked by the said crosslinking agent. Therefore, the said additional crosslinking agent can be considered to function as a surface crosslinking agent since it primarily crosslinks the surface of the superabsorbent resin, and the said crosslinking agent can be considered to function as an internal crosslinking agent, distinct from the said second crosslinking agent.

[0151] As the above-mentioned crosslinking agent, any compound that enables the introduction of crosslinking bonds during the polymerization of the above-mentioned acrylic acid-based monomer may be used. As a non-limiting example, the crosslinking agent is N,N'-methylenebisacrylamide, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol (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, triarylamine, ethylene glycol diglycidyl ether, propylene glycol, Polyfunctional crosslinking agents such as glycerin or ethylene carbonate may be used alone or in combination of two or more, but are not limited thereto.

[0152] Preferably, among these, polyalkylene glycol di(meth)acrylate-based compounds such as polyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, or polypropylene glycol (meth)acrylate may be used as the crosslinking agent.

[0154] The crosslinking polymerization of the acrylic acid-based monomer in the presence of such a crosslinking agent can be carried out by thermal polymerization, photopolymerization, or copolymerization in the presence of a polymerization initiator, and optionally a thickener, plasticizer, preservation stabilizer, antioxidant, etc., and specific details will be described later.

[0156] In addition, the superabsorbent resin may be in the form of particles having a particle size of 850 μm or less, for example, about 150 to 850 μm. In this case, such particle size may be measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 220.3 method. Here, if the superabsorbent resin contains a large amount of fine particles having a particle size of less than 150 μm, it is undesirable as it may degrade the overall physical properties of the superabsorbent resin.

[0158] Meanwhile, the superabsorbent resin may further include a cross-linked layer formed on the cross-linked polymer by further cross-linking the cross-linked polymer through an additional cross-linking agent. Here, the cross-linked layer is mainly formed on at least a portion of the surface of each of the superabsorbent resin particles and has a structure in which the cross-linked polymer within the superabsorbent resin is cross-linked by the additional cross-linking agent. This is intended to increase the cross-linking density on the surface of the superabsorbent resin particles. When the superabsorbent resin further includes a structure in which at least a portion of the superabsorbent resin particles is cross-linked by the additional cross-linking agent as described above, it has a structure in which the cross-linking density is higher on the outside than on the inside.

[0160] As the above additional crosslinking agent, any additional crosslinking agent conventionally used in the manufacture of superabsorbent resins may be used without any particular restrictions. For example, the above additional crosslinking agent may be one or more polyols selected from the group consisting of ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, 2-methyl-1,3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, tripropylene glycol, and glycerol; one or more carbonate compounds selected from the group consisting of ethylene carbonate, propylene carbonate, and glycerol carbonate; epoxy compounds such as ethylene glycol diglycidyl ether; oxazoline compounds such as oxazolidinone; polyamine compounds; oxazoline compounds; It may include mono-, di-, or polyoxazolidinone compounds; or cyclic urea compounds; etc.

[0162] Specifically, one or more, two or more, or three or more of the additional crosslinking agents described above may be used as the additional crosslinking agents, for example, ethylene carbonate-propylene carbonate (ECPC), propylene glycol and / or glycerol carbonate may be used.

[0164] Meanwhile, as described above, the superabsorbent resin may exhibit antibacterial activity against at least one of the Gram-negative bacteria and the Gram-positive bacteria. More specifically, the superabsorbent resin may exhibit antibacterial activity against one or more types of bacteria classified as Gram-positive bacteria. Alternatively, the superabsorbent resin may exhibit antibacterial activity against one or more types of bacteria classified as Gram-negative bacteria. Alternatively, the superabsorbent resin may exhibit antibacterial activity against one or more types of bacteria classified as Gram-negative bacteria and one or more types of bacteria classified as Gram-positive bacteria.

[0166] Here, the meaning of "exhibiting antibacterial activity against specific bacteria" is that the number of bacteria after absorbing artificial urine inoculated with test bacteria into a superabsorbent polymer to be checked for antibacterial activity and then culturing it is significantly reduced compared to the number of Reference bacteria after absorbing artificial urine inoculated with test bacteria into a superabsorbent polymer that does not contain antibacterial substances and then culturing it. Specifically, it means that the bacteriostatic reduction rate (%) calculated by the following mathematical formula 1 according to the antibacterial characteristic evaluation described later is 50% or more.

[0167] [Mathematical Formula 1]

[0168]

[0169] In the above formula,

[0170] C sample is the microbial concentration (Co) in a culture medium of a superabsorbent resin containing a bacteriostatic substance, and

[0171] C Reference is the microbial concentration (Co) in the culture medium of the superabsorbent resin of Comparative Example 1 that does not contain a bacteriostatic substance.

[0173] More preferably, the phrase "exhibits antibacterial activity against specific bacteria" means that the bacteriostatic reduction rate (%) calculated by the above mathematical formula 1 is 90% to 100%. In one embodiment, the bacteriostatic reduction rate (%) of the superabsorbent resin calculated by the above mathematical formula 1 may be 90% or more, 95% or more, 99% or more, 99% or more, 99.09% or more, 99.18% or more, 99.86% or more, 99.91% or more, 99.93% or more, or 99.96% or more and 100% or less.

[0175] Meanwhile, the aforementioned Gram-positive bacteria is a general term for bacteria that stain purple when stained by Gram staining. The cell walls of Gram-positive bacteria are composed of multiple layers of peptidoglycan, so they do not decolorize and remain purple even after treatment with ethanol following staining with a basic dye such as crystal violet. Examples of bacteria classified as Gram-positive include Enterococcus faecalis, Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecium, or Lactobacillus lactis.

[0177] In addition, the aforementioned Gram-negative bacteria is a general term for bacteria that stain red when stained by the Gram staining method, and which have a relatively small amount of peptidoglycan compared to Gram-positive bacteria. cell wall Instead of having, composed of lipopolysaccharides, lipoproteins, and other complex macromolecules outer membrane It has [unclear]. Accordingly, when treated with ethanol after staining with a basic dye such as crystal violet, decolorization occurs, and when counterstained with a red dye such as safranin, it exhibits a red color. Examples of bacteria classified as such Gram-negative bacteria include Proteus mirabilis, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, or Vibrio cholerae.

[0179] Therefore, since the above-mentioned Gram-positive and Gram-negative bacteria can cause various diseases upon contact, and can also cause secondary infections in severe patients with weakened immunity, it is desirable to use a single antimicrobial agent to exhibit antimicrobial activity against both the above-mentioned Gram-positive and Gram-negative bacteria.

[0181] Preferably, the superabsorbent resin may exhibit antibacterial activity against both Gram-negative bacteria and Gram-positive bacteria. In this case, the Gram-negative bacteria against which the superabsorbent resin exhibits antibacterial activity may be Proteus mirabilis or Escherichia coli, and the Gram-positive bacteria may be Enterococcus faecalis, but are not limited thereto.

[0183] Specifically, the superabsorbent resin may have a centrifugal retention capacity (CRC) of 20 to 45 g / g for 30 minutes in physiological saline (0.9 wt% sodium chloride aqueous solution) as measured according to the EDANA method WSP 241.3. If the centrifugal retention capacity (CRC) is less than 20 g / g, the ability to retain liquid after absorption is reduced, making the superabsorbent resin unsuitable for application in sanitary products. More specifically, the superabsorbent resin may have a centrifugal retention capacity (CRC) of 20 g / g or more, 25 g / g or more, 30 g / g or more, 33 g / g or more, 33.5 g / g or more, 34 g / g or more, 34.2 g / g or more, 34.5 g / g or more, 37 g / g or more, 37.1 g / g or more, or 37.6 g / g or more, and may have a CRC of 45 g / g or less, 43 g / g or less, 41 g / g or less, 39 g / g or less, 38 g / g or less, or 37.8 g / g or less.

[0185] Accordingly, the above-described superabsorbent resin containing a polymerizable antimicrobial monomer in a predetermined amount within a cross-linked polymer can have a centrifugal retention capacity (CRC) in the range of 20 to 45 g / g while simultaneously exhibiting excellent antimicrobial properties.

[0187] Method for manufacturing superabsorbent resin

[0188] Meanwhile, the above superabsorbent resin can be manufactured by including the following manufacturing method:

[0189] A step of preparing a monomer composition by mixing an acrylic acid-based monomer containing an acidic group, a polymerizable antimicrobial monomer represented by Chemical Formula 1, a crosslinking agent, and a polymerization initiator (Step 1);

[0190] A step of polymerizing the above monomer composition to form a hydrogel polymer (Step 2); and

[0191] It includes the step (step 3) of drying, grinding, and classifying the above-mentioned function gel polymer.

[0193] First, for the manufacture of a superabsorbent resin of one embodiment, step 1 is performed to prepare a monomer composition by mixing an acrylic acid-based monomer containing an acidic group, a polymerizable antimicrobial monomer represented by the above chemical formula 1, a basic substance, a crosslinking agent, and a polymerization initiator.

[0194] Here, for a more specific description of the acrylic acid monomer, polymerizable antimicrobial monomer, and crosslinking agent, refer to the above description, and in step 1, at least some of the acidic groups of the acrylic acid monomer are neutralized by mixing with a basic substance. Accordingly, the monomer composition may include an acrylic acid monomer in which at least some of the acidic groups have been neutralized.

[0196] Here, alkaline substances such as sodium hydroxide, potassium hydroxide, and ammonium hydroxide may be used as basic substances capable of neutralizing the acrylic acid-based monomer. Additionally, the basic substance may be added to the monomer composition in the form of an aqueous solution dissolved in water.

[0198] In addition, the degree of neutralization of the above acrylic acid monomer, that is, the content (mol%) of the neutralized acrylic acid monomer based on the total molar of the acrylic acid monomer used in the preparation of the crosslinked polymer, may be 40 to 95 mol%, or 40 to 80 mol%, or 45 to 75 mol%. If the degree of neutralization is excessively high, the neutralized monomer may precipitate, making it difficult for the polymerization to proceed smoothly; conversely, if the degree of neutralization is excessively low, there is a problem in that the absorption capacity of the polymer is significantly reduced, and it exhibits properties such as elastic rubber that are difficult to handle.

[0200] In addition, in the monomer composition, the polymerizable antimicrobial monomer may be used in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid-based monomer. If the polymerizable antimicrobial monomer is used in an amount of less than 0.1 part by weight per 100 parts by weight of the acrylic acid-based monomer, it is difficult to exhibit a sufficient antimicrobial effect, and if it is included in an amount of more than 1 part by weight per 100 parts by weight of the acrylic acid-based monomer, the radical polymerization reaction may be delayed due to the hydroxyl groups (OH) contained in the polymerizable antimicrobial monomer, and consequently, the polymerization of the acrylic acid-based monomer may be reduced, leading to insufficient polymerization or a longer polymerization time.

[0202] More specifically, the polymerizable antimicrobial monomer may be used in an amount of 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more, and 1 part by weight or less, relative to 100 parts by weight of the acrylic acid-based monomer.

[0204] In addition, in the monomer composition, such a crosslinking agent may be included in an amount of 0.01 to 1 part by weight per 100 parts by weight of the acrylic acid-based monomer to crosslink the polymerized polymer. If the content of the crosslinking agent is less than 0.01 parts by weight, the improvement effect due to crosslinking is negligible, and if the content of the crosslinking agent exceeds 1 part by weight, the absorption capacity of the superabsorbent resin may decrease. More specifically, the crosslinking agent may be included in an amount of 0.2 parts by weight or more, 0.3 parts by weight or more, 0.4 parts by weight or more, or 0.5 parts by weight or more, and 1 part by weight or less, relative to 100 parts by weight of the acrylic acid-based monomer.

[0206] In addition, the above polymerization initiator may be appropriately selected according to the polymerization method. When using a thermal polymerization method, a thermal polymerization initiator may be used, and when using a photopolymerization method, a photopolymerization initiator may be used. When using a hybrid polymerization method (a method using both heat and light), both a thermal polymerization initiator and a photopolymerization initiator may be used. However, even in the case of a photopolymerization method, a certain amount of heat is generated by light irradiation such as ultraviolet irradiation, and since a certain amount of heat is also generated as the polymerization reaction, which is an exothermic reaction, proceeds, a thermal polymerization initiator may be additionally used.

[0208] The above photopolymerization initiator can be used without limitation on its composition as long as it is a compound capable of forming radicals by light such as ultraviolet light.

[0210] For example, one or more selected from the group consisting of benzoin ether, dialkyl acetophenone, hydroxyl alkyl ketone, phenyl glyoxylate, benzyl dimethyl ketal, acyl phosphine, and α-aminoketone may be used as the photopolymerization initiator. Meanwhile, specific examples of acyl phosphine include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl(2,4,6-trimethylbenzoyl)phenylphosphineate, etc. A wider variety of photoinitiators is well described in Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Applications" (Elsevier 2007), p. 115, and is not limited to the examples described above.

[0212] The above photopolymerization initiator may be included in an amount of 0.001 to 1 part by weight per 100 parts by weight of the acrylic acid-based monomer. If the content of such photopolymerization initiator is less than 0.001 parts by weight, the polymerization rate may be slowed down, and if the content of the photopolymerization initiator exceeds 1 part by weight, the molecular weight of the superabsorbent resin may be small and the physical properties may become non-uniform. More specifically, the above photopolymerization initiator may be included in an amount of 0.005 parts by weight or more, or 0.00625 parts by weight or more, and 0.5 parts by weight or less, or 0.3 parts by weight or less, per 100 parts by weight of the acrylic acid-based monomer.

[0214] In addition, when the above polymerization initiator further includes a thermal polymerization initiator, one or more selected from the group of initiators 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), while examples of azo-based initiators include 2,2-azobis-(2-amidinopropane) dihydrochloride, 2,2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride, 2-(carbamoylazo)isobutylonitril, 2, Examples include 2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride and 4,4-azobis-(4-cyanovaleric acid). A wider variety of thermal polymerization initiators is well described in Odian's book 'Principles of Polymerization' (Wiley, 1981), p. 203, and is not limited to the examples mentioned above.

[0216] The above thermal polymerization initiator may be included in an amount of 0.001 to 1 part by weight per 100 parts by weight of the acrylic acid-based monomer. If the content of such thermal polymerization initiator is less than 0.001 parts by weight, additional thermal polymerization hardly occurs, so the effect of adding the thermal polymerization initiator may be negligible, and if the content of the thermal polymerization initiator exceeds 1 part by weight, the molecular weight of the superabsorbent resin may be small and the physical properties may become non-uniform. More specifically, the above thermal polymerization initiator may be included in an amount of 0.005 parts by weight or more, or 0.01 parts by weight or more, 0.1 parts by weight or more, or 0.125 parts by weight or more, and 0.5 parts by weight or less, or 0.3 parts by weight or less, per 100 parts by weight of the acrylic acid-based monomer.

[0218] Furthermore, if necessary, the monomer composition may additionally include one or more additives such as surfactants, thickeners, plasticizers, preservative stabilizers, and antioxidants.

[0220] In addition, the above-described monomer composition can be prepared in the form of a solution dissolved in a solvent.

[0221] The solvent that can be used at this time may be used without limitation in composition as long as it can dissolve the components described above, and, for example, one or more selected from 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, butyloractone, carbitol, methyl cellosolve acetate, and N,N-dimethylacetamide may be used in combination. The solvent may be included as the remainder excluding the components described above with respect to the total content of the monomer composition.

[0223] Next, step 2 is performed to form a hydrogel polymer by thermally polymerizing or photopolymerizing the monomer composition.

[0225] Here, regarding the thermal polymerization and photopolymerization methods, there are no particular limitations on the composition as long as they are commonly used methods capable of polymerizing the monomer composition to form a hydrogel polymer.

[0227] For example, the photopolymerization can be performed by irradiating ultraviolet light having an intensity of 3 to 30 mW or 10 to 20 mW at a temperature of 60 to 90°C or 70 to 80°C. When photopolymerizing under the above conditions, it is possible to form a cross-linked polymer with superior polymerization efficiency.

[0229] Additionally, when carrying out the above photopolymerization, it may be carried out in a reactor equipped with a movable conveyor belt or in a stainless steel container of a certain size, but the polymerization method described above is merely an example, and the present invention is not limited to the polymerization method described above.

[0231] In addition, when photopolymerization is carried out in a reactor equipped with a movable conveyor belt as described above, the form of the hydrogel polymer typically obtained may be a sheet-like hydrogel polymer with the width of the belt. At this time, the thickness of the polymer sheet varies depending on the concentration and injection speed of the injected monomer composition, but it is preferable to supply the monomer composition so that a sheet-like polymer with a thickness of about 0.5 to about 5 cm can be obtained. If the monomer composition is supplied to the extent that the thickness of the sheet-like polymer is excessively thin, the production efficiency is low and is undesirable; and if the thickness of the sheet-like polymer exceeds 5 cm, the polymerization reaction may not occur evenly across the entire thickness due to the excessively thick thickness.

[0233] The moisture content of the hydrogel polymer obtained from Step 2 above may be about 40 to about 80 weight percent relative to the total weight of the hydrogel polymer. Meanwhile, throughout this specification, "moisture content" refers to the amount of water contained relative to the total weight of the hydrogel polymer, which is the value obtained by subtracting the weight of the polymer in a dry state from the weight of the hydrogel polymer. Specifically, it is 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 by infrared heating. At this time, the drying conditions are set such that the temperature is raised from room temperature to about 180°C and then maintained at 180°C, and the total drying time is set to 20 minutes, including a 5-minute temperature raising step, to measure the moisture content.

[0235] Meanwhile, after the preparation of the above-mentioned hydrogel polymer, a coarse grinding process to grind the prepared hydrogel polymer may be optionally performed prior to the subsequent drying and grinding processes.

[0236] The above-mentioned coarse grinding process is a process for increasing drying efficiency in a subsequent drying process and controlling the particle size of the superabsorbent resin powder being manufactured. At this time, the grinder used 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 meat chopper, and a disc cutter, but is not limited to the examples described above.

[0238] The above coarse grinding process can be performed, for example, such that the size of the hydrogel polymer is about 1 to about 10 mm. Grinding the hydrogel polymer to a particle size of less than 1 mm is not technically easy due to the high water content of the hydrogel polymer, and a phenomenon of aggregation between the ground particles may also occur. 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 is negligible.

[0240] Next, step 3 is performed to form a superabsorbent resin containing a cross-linked polymer by drying, grinding, and classifying the hydrogel polymer prepared in step 2 above.

[0242] The above drying method can be selected and used without limitation on its composition, as long as it is commonly used as a drying process for hydrogel polymers. Specifically, the drying step can be carried out by methods such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation.

[0244] Specifically, the drying can be performed at a temperature of about 100 to about 250°C. If the drying temperature is below 100°C, the drying time may become excessively long and there is a risk that the physical properties of the finally formed superabsorbent resin may deteriorate. If the drying temperature exceeds 250°C, only the surface of the polymer may be dried excessively, which may result in fine powder being generated during the subsequent grinding process and there is a risk that the physical properties of the finally formed superabsorbent resin may deteriorate. Therefore, preferably, the drying can be carried out at a temperature of 100°C or higher, or 110°C or higher, and 200°C or lower, or 180°C or lower.

[0246] The moisture content of the polymer after such a drying step may be about 5 to about 10 weight%.

[0248] Meanwhile, a grinding process is performed after the above drying process. The grinding process can be performed so that the particle size of the polymer powder, i.e., the superabsorbent resin particles, is about 150 to about 850 μm. Specifically, the grinder used to grind to such a particle size may be a pin mill, hammer mill, screw mill, roll mill, disc mill, or jog mill, but is not limited thereto.

[0250] In addition, after the grinding step described above, in order to control the physical properties of the superabsorbent resin powder that is finalized into a product, the ground polymer powder may be further classified according to particle size.

[0252] The superabsorbent resin obtained as a result of the above-described process may have a fine powder form comprising a cross-linked polymer in which an acrylic acid-based monomer and a polymerizable antimicrobial monomer are cross-linked via a cross-linking agent. Specifically, the superabsorbent resin may have a fine powder form having a particle size of 150 to 850 μm.

[0254] Next, the method may further include a step of surface crosslinking by heat-treating the superabsorbent resin prepared in Step 3 above in the presence of an additional crosslinking agent. Through this step, a superabsorbent resin may be prepared that further comprises a surface crosslinked layer in which the crosslinked polymer is additionally crosslinked on the crosslinked polymer via an additional crosslinking agent. In this case, the description of the additional crosslinking agent refers to the above description.

[0256] The above surface crosslinking is a step that increases the crosslinking density near the surface of the superabsorbent resin in relation to the crosslinking density inside the particle. Generally, an additional crosslinking agent is applied to the surface of the resin. Thus, this reaction occurs on the surface of the resin particles, which improves the crosslinking properties on the surface of the particles without substantially affecting the interior of the particles. Therefore, the surface-crosslinked superabsorbent resin has a higher degree of crosslinking near the surface than inside.

[0258] In addition, the above additional crosslinking agent may be used in an amount of about 0.001 to about 5 parts by weight per 100 parts by weight of the superabsorbent resin. For example, the above additional crosslinking agent may be used in an amount of 0.005 parts by weight or more, 0.01 parts by weight or more, or 0.05 parts by weight or more, and 5 parts by weight or less, 4 parts by weight or less, or 3 parts by weight or less, per 100 parts by weight of the superabsorbent resin. By adjusting the content range of the additional crosslinking agent to the range described above, a superabsorbent resin exhibiting excellent absorption properties can be manufactured.

[0260] In addition, there are no limitations on the composition of the method for mixing the additional crosslinking agent with the superabsorbent resin. For example, methods such as mixing the additional crosslinking agent and the superabsorbent resin by placing them in a reaction vessel, spraying the additional crosslinking agent onto the superabsorbent resin, or continuously supplying the superabsorbent resin and the additional crosslinking agent to a continuously operated mixer for mixing may be used.

[0262] The above surface crosslinking can be performed by heating the superabsorbent resin with the aforementioned additional crosslinking agent at a temperature of about 80 to about 220°C for about 15 to about 100 minutes. If the crosslinking reaction temperature is below 80°C, the surface crosslinking reaction may not occur sufficiently, and if it exceeds 220°C, the surface crosslinking reaction may proceed excessively. In addition, if the crosslinking reaction time is excessively short (less than 15 minutes), sufficient crosslinking reaction cannot be performed, and if the crosslinking reaction time exceeds 100 minutes, the crosslinking density on the particle surface may become excessively high due to the excessive surface crosslinking reaction, which may result in a deterioration of physical properties. More specifically, it can be performed by heating at a temperature of 120°C or higher, or 140°C or higher, or 200°C or lower, or 180°C or lower, for 20 minutes or more, or 40 minutes or more, or 70 minutes or less, or 60 minutes or less.

[0264] The means for raising the temperature for the above-mentioned surface crosslinking reaction is 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 the present invention is not limited thereto. Furthermore, the temperature of the supplied heat medium can be appropriately selected by considering the means of the heat medium, the heating rate, and the target temperature. Meanwhile, heating methods using electricity or gas may be used as the directly supplied heat source, but the present invention is not limited to the examples described above.

[0266] Meanwhile, furthermore, an article including the superabsorbent resin described above is provided.

[0267] The above-mentioned articles may be one or more selected from the group consisting of absorbent articles, sanitary products, soil repair agents, waterproofing materials for civil engineering, waterproofing materials for construction, seedling sheets, freshness preservatives, materials for compresses, electrical insulators, articles for oral care, articles for teeth, articles for cosmetics, and articles for skin.

[0268] In this case, sanitary products containing the superabsorbent resin may include children's paper diapers, adult diapers, or sanitary pads. Such sanitary products may have the composition of conventional sanitary products, except that the superabsorbent resin of the above-described embodiment is included in the absorbent body.

[0270] Preferred embodiments are presented below to aid in understanding the invention. However, the following embodiments are intended only to illustrate the invention and do not limit the invention to these embodiments.

[0272] Preparation Example A: Preparation of Polymerizable Antimicrobial Monomer 1-1

[0273]

[0274] Hydroquinone (21 g, 19.1 mmol) and triethylamine (TEA, 38.7 g, 38.2 mmol) were placed in a 250 mL round-bottom flask and dissolved in 150 mL of tetrahydrofuran (THF). Then, the temperature of the reactor was lowered to -78 °C in an ice bath using dry ice and acetone, and acryloyl chloride (17.3 g, 19.1 mmol) was slowly added dropwise to the reaction solution over 20 minutes. After the reaction was complete, the reaction mixture was sufficiently diluted in ethyl acetate and washed with EtOAc / brine to separate the organic layer. Water was removed with magnesium sulfate, and the passed-through solution was concentrated under reduced pressure. The resulting solution was then purified by hexane / ethyl acetate column chromatography to obtain polymerizable antimicrobial monomer 1-1 (25.7 g, yield 82%). Of the obtained polymerizable antimicrobial monomer 1-1 1 The H NMR spectrum is shown in Figure 1.

[0275] MS[M+H] + = 164.05

[0276] 1H NMR (500 MHz, DMSO, δ [ppm]): 6.2 (dd, 1H, CH2=CH), 6.3 (dd, 1H, CH2=CH), 6.5 (dd, 1H, CH2=CH), 6.7 (d, 1H, Ar-H), 6.9 (d, 1H, Ar-H), 9.46 (s, 1H, OH).

[0278] Preparation Example B: Preparation of Polymerizable Antimicrobial Monomers 1-2

[0279]

[0280] Resorcinol (21 g, 19.1 mmol) and triethylamine (TEA, 38.7 g, 38.2 mmol) were placed in a 250 mL round-bottom flask and dissolved in 150 mL of tetrahydrofuran (THF). Then, the temperature of the reactor was lowered to -78 °C in an ice bath using dry ice and acetone, and acryloyl chloride (17.3 g, 19.1 mmol) was slowly added dropwise to the reaction solution over 20 minutes. After the reaction was complete, the reaction mixture was sufficiently diluted in ethyl acetate and washed with EtOAc / brine to separate the organic layer. Water was removed with magnesium sulfate, and the passed-through solution was concentrated under reduced pressure. The solution was then purified by hexane / ethyl acetate column chromatography to obtain polymerizable antimicrobial monomer 1-2 (22.3 g, yield 71%).

[0281] MS[M+H] + = 164.05

[0282] 1 H NMR (500 MHz, DMSO, δ [ppm]): 6.2 (dd, 1H, CH2=CH), 6.3 (dd, 1H, CH2=CH), 6.5 (dd, 1H, CH2=CH), 6.4 (d, 1H, Ar-H), 6.6 (d, 1H, Ar-H), 9.89 (s, 1H, OH).

[0284] Example - Preparation of a superabsorbent resin composition

[0285] Example 1

[0286] (Step 1) A monomer composition was prepared by adding 100 g of acrylic acid, 0.25 g of polyethylene glycol diacrylate (Mn= 575) as a crosslinking agent, 0.00625 g of phenylbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide as a photoinitiator, 0.125 g of sodium persulfate (SPS) as a thermal initiator, 100 g of a 40% sodium hydroxide solution, and 0.2 g of the polymerizable antimicrobial monomer 1-1 prepared in Preparation Example A above to a 3L glass container equipped with a stirrer, a nitrogen injector, and a thermometer, while continuously introducing nitrogen. At this time, the degree of neutralization of the acrylic acid and the polymerizable antimicrobial monomer 1-1 was 70 mol%.

[0287] (Step 2) Subsequently, the monomer composition was placed in a stainless steel container measuring 250 mm in width, 250 mm in length, and 30 mm in height, and irradiated with ultraviolet light for 60 seconds in an 80°C UV chamber (irradiation dose: 10 mV / cm² 2 A sheet-shaped hydrogel polymer was prepared by aging for 2 minutes after polymerization.

[0288] (Step 3) The prepared hydrogel polymer was cut into pieces measuring 3 cm * 3 cm, then fed into a meat chopper to crush the polymer, thereby obtaining hydrogel particle crumbs with a size of 1 mm to 10 mm. Subsequently, the obtained crumbs were spread to a thickness of approximately 30 mm on stainless wire gauze with a pore size of 600 μm and dried in a 120°C hot air oven for 11 hours. The dried polymer obtained in this way was crushed using a grinder and classified through a standard sieve of ASTM specifications to obtain a base resin with a particle size of 150 to 850 μm, which was used as a superabsorbent resin.

[0290] Example 2

[0291] A superabsorbent resin was prepared using the same method as in Example 1, except that 0.5 g of the polymerizable antimicrobial monomer 1-1 prepared in Preparation Example A was used in Example 1 above.

[0293] Example 3

[0294] A superabsorbent resin was prepared using the same method as in Example 1, except that 1.0 g of the polymerizable antimicrobial monomer 1-1 prepared in Preparation Example A was used in Example 1.

[0296] Example 4

[0297] A superabsorbent resin was prepared using the same method as in Example 1, except that the polymerizable antimicrobial monomer 1-2 prepared in Preparation Example B was used instead of the polymerizable antimicrobial monomer 1-1 prepared in Preparation Example A in Example 1.

[0299] Example 5

[0300] A superabsorbent resin was prepared using the same method as in Example 4, except that 0.5 g of the polymerizable antimicrobial monomer 1-2 prepared in Preparation Example B was used in Example 4.

[0302] Example 6

[0303] A superabsorbent resin was prepared using the same method as in Example 4, except that 1.0 g of the polymerizable antimicrobial monomer 1-2 prepared in Preparation Example B was used in Example 4.

[0305] Comparative Example 1

[0306] A superabsorbent resin was prepared using the same method as in Example 1, except that the polymerizable antimicrobial monomer 1-1 was not used in Example 1.

[0308] Reference Example 1

[0309] A superabsorbent resin was prepared using the same method as in Example 1, except that 0.05 g of the polymerizable antimicrobial monomer 1-1 prepared in Preparation Example A was used in Example 1 above.

[0311] Experimental Example 1

[0312] The physical properties of the superabsorbent resins prepared in the above examples and comparative examples were evaluated in the following manner, and the results are shown in Table 4 below.

[0313] Unless otherwise indicated, all of the following physical property evaluations were conducted under constant temperature and humidity conditions (23±1℃, relative humidity 50±10%), and physiological saline or saline refers to a 0.9 wt% sodium chloride (NaCl) aqueous solution.

[0315] (1) Evaluation of antimicrobial properties against E. coli

[0316] 2 g of the superabsorbent resin prepared in the above examples and comparative examples was placed in a 250 cell culture flask, and 50 ml of artificial urine inoculated with the test microorganism Escherichia coli (ATCC 25922) at a concentration of 3000±300 CFU / ml was injected. Subsequently, the mixture was stirred for about 1 minute to allow the superabsorbent resin to sufficiently absorb the artificial urine solution. Once the solution was sufficiently absorbed, the resin exhibited a gel-like form and was cultured for 12 hours in an incubator (JEIO TECH) maintained at 35°C. After the culture was completed, 150 ml of 0.9 wt% NaCl solution was added to the sample and shaken for about 1 minute, and this diluted solution was plated on an Agar medium plate. Serial dilution was then performed to enable colony counting, using a 0.9 wt% NaCl solution during this process. The bacteriostatic performance was calculated by considering the dilution concentration, calculating the initial microbial concentration (Co, CFU / mL), and then calculating the bacteriostatic reduction rate (%) of Escherichia coli (E. coli, ATCC 25922) using the following mathematical formula 1, and the results are shown in Table 4 below.

[0317] [Mathematical Formula 1]

[0318]

[0319] In the above formula,

[0320] C sample is the microbial concentration (Co) in a culture medium of a superabsorbent resin containing a bacteriostatic substance, and

[0321] C Reference is the microbial concentration (Co) in the culture medium of the superabsorbent resin of Comparative Example 1 that does not contain a bacteriostatic substance.

[0323] At this time, the artificial urine used for the above antibacterial property evaluation was prepared as follows.

[0324] First, a stock solution was prepared by adding the reagents listed in Table 1 below to a 1000 mL flask in the specified weights, filling with water up to the 1000 mL mark, and mixing; a cationic solution was prepared by adding the reagents listed in Table 2 below to a 100 mL flask in the specified weights, filling with water up to the 20 mL mark, and mixing; and a urea / glucose solution was prepared by adding the reagents listed in Table 3 below to a 100 mL flask in the specified weights, filling with water up to the 100 mL mark, and mixing.

[0325] Next, the prepared stock solution and cationic solution were sterilized at 120°C for 15 minutes using an autoclave and then cooled sufficiently to room temperature, and the prepared urea / glucose solution was purified using a 0.22 µm syringe filter (Hydrophilic, manufactured by Sartorius Steim).

[0326] Subsequently, artificial urine was prepared by thoroughly mixing 940 mL of stock solution, 10 mL of cationic solution, and 50 mL of urea / glucose solution. The prepared artificial urine is typically refrigerated and usable for 2 weeks, and artificial urine that has passed 2 weeks was not used in the experiment.

[0328] Stock solution Reagent name Weight (g) Sodium chloride 8.7660 Potassium phosphate dibasic trihydrate 4.5644 Sodium dihydrogen phosphate (dihydrate) 1.5602 Ammonium chloride 2.6745 Sodium sulfate decahydrate 6.4440 Lactic acid (85% in H2O) 0.5299 Yeast extract 20.0000

[0329] Cationic solution Reagent name Weight (g) Magnesium chloride (hexahydrate) 1.2198 Calcium chloride (dihydrate) 0.8821

[0330] Urea / glucose solution Reagent name Weight (g) Urea 36.0360 D-glucose 0.1802

[0331] (2) Centrifuge Retention Capacity (CRC)

[0332] According to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 241.3, the centrifugal retention capacity of each superabsorbent resin of each example and comparative example was measured based on the absorption ratio under no load.

[0333] Specifically, superabsorbent resin W0 (g) (about 0.2g) was uniformly placed into a nonwoven bag and sealed, then immersed in physiological saline solution (0.9 wt% sodium chloride aqueous solution) at room temperature. After 30 minutes, the water was drained from the bag for 3 minutes using a centrifuge under conditions of 250g, and the weight of the bag W2 (g) was measured. In addition, the same operation was performed without using resin, and the weight W1 (g) was measured. Using each obtained mass, the CRC (g / g) was calculated according to the following formula, and the results are shown in Table 4 below.

[0334] [Mathematical Formula 2]

[0335] CRC (g / g) = {[W2(g) - W1(g)] / W0(g)} - 1

[0336] In the above mathematical formula 2,

[0337] W0(g) is the initial weight (g) of the superabsorbent resin, and

[0338] W1(g) is the weight of the bag measured after absorbing the bag by immersing it in physiological saline for 30 minutes without using superabsorbent resin, and then dehydrating it using a centrifuge at 250G for 3 minutes.

[0339] W2(g) is the weight of the bag containing the superabsorbent polymer, measured after soaking the superabsorbent polymer in physiological saline at room temperature for 30 minutes, and then dehydrating it at 250g for 3 minutes using a centrifuge.

[0341] Types of antimicrobial monomers Content of antimicrobial monomer 1) Antimicrobial properties against E. coli Superabsorbent resin properties CFU / mL SUE Log CFU / mL SUE Average reduction rate (%) CRC(g / g) Example 1 1-1 0.2 1.0E+04 4.01 99.18 34.5 Example 2 1-1 0.5 1.1E+03 3.05 99.91 37.1 Example 3 1-1 1.0 4.6E+02 2.66 99.96 37.8 Example 4 1-2 0.2 1.1E+04 4.06 99.09 34.2 Example 5 1-2 0.5 1.8E+03 3.25 99.86 37.0 Example 6 1-2 1.0 9.4E+02 2.97 99.93 37.6 Comparative Example 1 1-1 0 1.2E+06 6.10 0 32.7 Reference Example 1 1-1 0.05 8.4E+05 5.92 32.75 33.0

[0342] 1) Weight part relative to 100 weight parts of acrylic acid monomer

[0344] Referring to Table 4 above, it can be confirmed that the superabsorbent resin of the example exhibits improved centrifugal retention capacity (CRC) compared to the superabsorbent resin of Comparative Example 1, which did not use a polymerizable antimicrobial monomer during acrylic acid monomer polymerization, and the superabsorbent resin of Reference Example 1, which used 0.05 parts by weight of a polymerizable antimicrobial monomer per 100 parts by weight of acrylic acid monomer, while simultaneously exhibiting excellent antimicrobial activity against Escherichia coli, one of the Gram-negative bacteria.

Claims

Claim 1 A superabsorbent resin comprising: an acrylic acid-based monomer containing acidic groups, wherein at least a portion of said acidic groups is neutralized; a polymerizable antimicrobial monomer represented by the following chemical formula 1; and a crosslinking agent; wherein the polymerizable antimicrobial monomer is included in the crosslinking polymer in an amount of 0.1 to 1 weight part per 100 weight parts of said acrylic acid-based monomer: [Chemical Formula 1] In the above formula 1, R1 to R3 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, or a carboxyl group (COOH); L is a single bond or an arylene having 6 to 60 carbon atoms; and A is an aromatic ring having 6 to 60 carbon atoms, wherein the arylene and the aromatic ring are each independently unsubstituted or substituted with one or more substituents selected from the group consisting of hydroxyl, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms. Claim 2 A superabsorbent resin according to claim 1, wherein R1 to R3 are each independently hydrogen, methyl, or carboxyl groups. Claim 3 In claim 1, a superabsorbent resin in which L is a single bond, phenylene, or naphthylene. Claim 4 A superabsorbent resin according to claim 1, wherein A is a benzene or naphthalene ring, wherein the benzene and naphthalene rings are each independently unsubstituted or substituted with one to three substituents selected from the group consisting of hydroxyl, alkyl having 1 to 10 carbon atoms, and alkoxy having 1 to 10 carbon atoms. Claim 5 In claim 1, the polymerizable antimicrobial monomer is a superabsorbent resin represented by any one of the following chemical formulas 1-1 to 1-3: [Chemical Formula 1-1] [Chemical Formula 1-2] [Chemical Formula 1-3] In the above chemical formulas 1-1 to 1-3, L' is a single bond, phenylene, or naphthylene, R is a hydroxyl, an alkyl having 1 to 10 carbon atoms, or an alkoxy having 1 to 10 carbon atoms, a is an integer from 0 to 3, and if a is 2 or more, two or more Rs are identical or different from each other, and R1 to R3 are as defined in claim 1. Claim 6 In claim 1, the polymerizable antimicrobial monomer is a superabsorbent resin selected from the group consisting of: . Claim 7 A superabsorbent resin according to claim 1, wherein the polymerizable antimicrobial monomer is included in the cross-linked polymer in an amount of 0.2 to 1 weight part per 100 weight parts of the acrylic acid-based monomer. Claim 8 In claim 1, the superabsorbent resin is a superabsorbent resin that exhibits antibacterial activity against at least one of Gram-negative bacteria and Gram-positive bacteria. Claim 9 A superabsorbent resin according to claim 8, wherein the Gram-negative bacterium is Proteus mirabilis or Escherichia coli, and the Gram-positive bacterium is Enterococcus faecalis. Claim 10 In claim 1, the superabsorbent resin is a superabsorbent resin having a centrifugation retention capacity (CRC) of 20 to 45 g / g for 30 minutes in physiological saline (0.9 wt% sodium chloride aqueous solution) as measured according to the EDANA method WSP 241.

3. Claim 11 A method for manufacturing a superabsorbent resin of claim 1, comprising the steps of: preparing a monomer composition by mixing an acrylic acid-based monomer containing an acidic group, a polymerizable antimicrobial monomer represented by the following chemical formula 1, a crosslinking agent, and a polymerization initiator (Step 1); polymerizing the monomer composition to form a hydrogel polymer (Step 2); and drying, grinding, and classifying the hydrogel polymer (Step 3), wherein the polymerizable antimicrobial monomer is used in an amount of 0.1 to 1 weight part per 100 weight parts of the acrylic acid-based monomer: [Chemical Formula 1] In the above formula 1, R1 to R3 are each independently hydrogen, an alkyl group having 1 to 4 carbon atoms, or a carboxyl group (COOH); L is a single bond; or an arylene having 6 to 60 carbon atoms; and A is an aromatic ring having 6 to 60 carbon atoms, wherein the arylene and the aromatic ring are unsubstituted or substituted with one or more substituents selected from the group consisting of hydroxyl, an alkyl group having 1 to 10 carbon atoms, and an alkoxy group having 1 to 10 carbon atoms. Claim 12 A method for manufacturing a superabsorbent resin according to claim 11, wherein the polymerizable antimicrobial monomer is used in an amount of 0.2 to 1 weight part per 100 weight parts of the acrylic acid-based monomer. Claim 13 An article comprising a superabsorbent resin according to any one of claims 1 to 10. Claim 14 In paragraph 13, the above article is one or more selected from the group consisting of absorbent articles, sanitary products, soil repair agents, waterproofing materials for civil engineering, waterproofing materials for construction, seedling sheets, freshness preservatives, poultice materials, electrical insulators, oral products, dental products, cosmetic products, and skin products.

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