Superabsorbent polymer and method for producing the same

Abstract

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

Description

[Technical Field]

[0001] Mutual citation with related applications (etc.) This application claims priority rights based on Korean Patent Application No. 10-2021-0109663 dated August 19, 2021, and Korean Patent Application No. 10-2022-0102205 dated August 16, 2022, and all content disclosed in the documents of said Korean patent applications is incorporated herein by reference.

[0002] This invention relates to a superabsorbent polymer that exhibits improved bacterial growth inhibitory properties without a decrease in the absorption performance of the superabsorbent polymer, and a method for producing the same. [Background technology]

[0003] Superabsorbent polymers (SAPs) are synthetic polymers capable of absorbing approximately 500 to 1,000 times their own weight in water. They are named differently by each developing company, such as SAM (Super Absorbency Material) and AGM (Absorbent Gel Material). Superabsorbent polymers have begun to be used in sanitary products and are now widely used not only in hygiene products such as children's diapers, but also in horticultural soil water retention agents, waterproofing materials for civil engineering and construction, seedling sheets, freshness preservatives in the food distribution sector, and materials for poultices and electrical insulation.

[0004] In particular, superabsorbent polymers are most widely used in hygiene products and disposable absorbent products such as children's diapers and adult diapers. Therefore, when bacteria proliferate in such hygiene products and disposable absorbent products, it can not only induce various diseases but also cause secondary odors, which is a problem. In response to this, there have been attempts to introduce various bacterial growth inhibitors and deodorizing or antibacterial functional components into superabsorbent polymers and other materials.

[0005] However, when introducing antibacterial agents that suppress bacterial growth into superabsorbent polymers, selecting and introducing antibacterial agent components that exhibit excellent bacterial growth suppression and deodorizing properties while being harmless to the human body, economically viable, and without degrading the basic physical properties of the superabsorbent polymer was not so easy.

[0006] Therefore, there is a continuing need for the development of technologies for superabsorbent polymers that can effectively suppress bacterial growth without compromising the basic physical properties of the polymer. [Overview of the project] [Problems that the invention aims to solve]

[0007] Therefore, the present invention provides a superabsorbent polymer and a method for producing the same that can exhibit improved bacterial growth inhibitory properties without reducing the absorption performance of the superabsorbent polymer. [Means for solving the problem]

[0008] According to one embodiment of the present invention, The present invention provides a superabsorbent polymer comprising an acrylic acid monomer containing an acidic group, in which at least a portion of the acidic group is neutralized; a polymerizable antimicrobial monomer represented by the following chemical formula 1; and a crosslinking agent.

[0009] [ka]

[0010] In the aforementioned chemical 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 with 6 to 60 carbon atoms. A is an aromatic ring with 6 to 60 carbon atoms. Here, the arylene and aromatic ring are each independently unsubstituted or substituted with one or more substituents selected from the group consisting of hydroxyl, C1-C10 alkyl, and C1-C10 alkoxy.

[0011] According to other embodiments of the present invention, Step 1: Prepare a monomer composition by mixing an acrylic acid monomer containing an acidic group, a polymerizable antimicrobial monomer represented by the chemical formula 1, a crosslinking agent, and a polymerization initiator. Step 2: Polymerizing the monomer composition to form a water-containing gel polymer; and The present invention provides a method for producing a superabsorbent polymer, comprising the steps of drying, pulverizing, and classifying the aforementioned water-containing gel polymer (step 3).

[0012] Furthermore, according to yet another embodiment of the present invention, an article containing the superabsorbent resin is provided. [Effects of the Invention]

[0013] The superabsorbent polymer of the present invention can exhibit antibacterial properties that suppress the growth of bacteria that are harmful to the human body and may induce secondary odors.

[0014] Specifically, the superabsorbent polymer can be manufactured using a polymerizable antimicrobial monomer with a specific structure during the formation of a crosslinked polymer. This allows it to exhibit antimicrobial properties against at least one of Gram-positive bacteria and Gram-negative bacteria while maintaining excellent water retention capacity, unlike when using other antimicrobial agents.

[0015] Furthermore, the polymerizable antimicrobial monomer is copolymerized with an acrylic acid monomer. When the polymerizable antimicrobial monomer or a polymer obtained by polymerizing the polymerizable antimicrobial monomer is simply mixed with a superabsorbent resin, the risk of the polymerizable antimicrobial monomer leaching out is reduced, thus potentially preventing any risk of impairing human body stability due to the leaching of the antimicrobial agent.

[0016] Therefore, the superabsorbent resin can be very preferably applied to various sanitary products such as not only baby diapers but also adult diapers that require antibacterial properties against bacteria.

Brief Description of Drawings

[0017] [Figure 1] FIG. 1 shows the 1H NMR spectrum of the polymerizable antibacterial monomer 1-1.

Modes for Carrying Out the Invention

[0018] The terms used in this specification are merely used to explain 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", "including", or "having" are intended to specify the presence of the implemented features, steps, components, or combinations thereof, and should be understood not to preclude in advance the presence or addition possibility of one or more other features, steps, components, or combinations thereof.

[0019] Also, 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 directly formed on each layer or element, or that other layers or elements can be additionally formed between each layer, on the object, or on the substrate.

[0020] The present invention can be subjected to various modifications and can have various forms. Specific embodiments are exemplified and will be described in detail below. However, this is not intended to limit the present invention to a specific disclosed form, and should be understood to include all modifications, equivalents, or alternatives included in the spirit and technical scope of the present invention.

[0021] Furthermore, the technical terms used herein are merely for the purpose of referring to specific examples and are not intended to limit the invention. The singular forms used herein also include the plural forms unless the text explicitly indicates otherwise.

[0022] On the other hand, the term "(meth)acrylate" as used in this specification includes both acrylate and methacrylate.

[0023] Furthermore, in this specification, the alkyl group may be linear or branched, and the number of carbon atoms is not particularly limited, but 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 alkyl group 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-dimethylpropyl Examples include, but are not limited to, ethylbutyl, 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, 2,4,4-trimethyl-2-pentyl, 2-propylpentyl, n-nonyl, and 2,2-dimethylheptyl. Furthermore, in this specification, the above-mentioned description of alkyl groups can be applied to alkylenes, except that they are divalent groups.

[0024] Furthermore, in this specification, the alkoxy group may be linear or branched, and the number of carbon atoms is not particularly limited, but is preferably 1 to 10. In one embodiment, the number of carbon atoms of the alkoxy group is 1 to 6. Specific examples of the alkoxy group include, but are not limited to, methoxy, ethoxy, n-propoxy, isopropoxy, and n-butoxy.

[0025] Furthermore, in this specification, the aryl group is not particularly limited, but it is preferably one having 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. In one embodiment, the aryl group has 6 to 30 carbon atoms. In another embodiment, the aryl group has 6 to 20 carbon atoms. Examples of monocyclic aryl groups include, but are not limited to, phenyl, biphenylyl, and terphenylyl groups. Examples of polycyclic aryl groups include, but are not limited to, naphthyl, anthryl, phenanthryl, pyrenyl, perilenyl, chrysenyl, and fluorenyl groups. Furthermore, in this specification, the above-described explanation regarding aryl groups can be applied to arylene, except that it is a divalent group.

[0026] Furthermore, in this specification, an aromatic ring means a monocyclic or polycyclic ring containing only carbon as a ring-forming atom and having aromaticity as a whole molecule. The number of carbon atoms in the aromatic ring is 6 to 60, 6 to 30, or 6 to 20, but is not limited thereto. Examples of aromatic rings include benzene rings, naphthalene rings, anthracene rings, phenanthrene rings, pyrene rings, etc., but is not limited thereto.

[0027] As used in the specification of this invention, the terms "polymer" or "polymer" refer to a state in which acrylic acid monomers have been polymerized, and can encompass all moisture content ranges or particle size ranges. Among the polymers, those in the state before drying after polymerization and with a moisture content of about 40% by weight or more can be called water-containing gel polymers, and particles obtained by crushing and drying such water-containing gel polymers can be called crosslinked polymers.

[0028] Furthermore, the term "superabsorbent polymer particles" refers to particulate matter containing an acrylic acid monomer that contains acidic groups, and in which at least a portion of the acidic groups are neutralized, an acrylic acid monomer is polymerized and crosslinked by an internal crosslinking agent to form a crosslinked polymer.

[0029] Furthermore, the term "superabsorbent polymer" can mean, depending on the context, a crosslinked polymer formed by polymerizing acrylic acid monomers containing acidic groups, in which at least a portion of the acidic groups have been neutralized, or a base resin in powder form consisting of superabsorbent polymer particles obtained by grinding the crosslinked polymer, or it can be used to encompass all processes that have been performed on the crosslinked polymer or the base resin to make it suitable for commercialization, such as surface crosslinking, fine powder regranulation, drying, grinding, classification, etc.

[0030] Conventional superabsorbent polymers have been used to ensure antibacterial and deodorizing properties by introducing metal compounds with antibacterial properties or organic compounds containing cations or alcohol functional groups as additives. However, this has resulted in reduced safety of the superabsorbent polymer, a decrease in basic physical properties such as absorption characteristics, and problems with the persistence of antibacterial properties and the leakage of antibacterial substances.

[0031] As an example, attempts have been made to introduce antibacterial components containing antimicrobial metal ions such as silver, copper, and zinc into superabsorbent polymers. Such antibacterial metal ion-containing components can destroy the cell walls of microorganisms such as bacteria, killing bacteria that possess enzymes that can induce unpleasant odors in superabsorbent polymers, thereby imparting deodorizing properties. However, in the case of the aforementioned metal ion-containing components, they are classified as biocidal substances that can kill even microorganisms that are beneficial to the human body. As a result, when the superabsorbent polymer is applied to hygiene products such as diapers for children or adults, the introduction of such metal ion-containing antibacterial components is generally avoided as much as possible.

[0032] In the past, when introducing antibacterial agents that suppress bacterial growth into superabsorbent polymers, the main method applied was to mix a small amount of the antibacterial agent into the superabsorbent polymer. However, when using such a mixing method, it was difficult to maintain uniform bacterial growth suppression characteristics over time. Moreover, with such a mixing method, there was a possibility of uneven application and detachment of the antibacterial agent component during the mixing process of the superabsorbent polymer and the antibacterial agent, and there were also disadvantages such as the need to install new equipment for the mixing.

[0033] Furthermore, bacteria are incredibly diverse, with over 5,000 known species. Specifically, bacteria exhibit diverse cell shapes, including spherical, rod-shaped, and spiral forms, and their oxygen requirements vary from one bacterium to another. They are classified into exhalative, facultative, and anaerobic bacteria. Consequently, it is generally not easy for a single antimicrobial agent to possess a physical / chemical mechanism capable of damaging the cell membrane / cell wall or denaturing proteins in such a diverse range of bacteria.

[0034] However, when a monomer containing a hydroxyl group (OH) with a specific structure is polymerized together with an acrylic acid monomer to produce a superabsorbent polymer, it has been confirmed that it can exhibit antibacterial activity against at least one of Gram-positive bacteria and Gram-negative bacteria while showing absorption performance above a certain level, thus completing the present invention.

[0035] Specifically, when the polymerizable antimicrobial monomer represented by chemical formula 1 comes into contact with bacteria, the aromatic ring structure substituted with hydroxyl groups can bind to protein substances essential for bacterial metabolism, thereby inhibiting bacterial growth. More specifically, the hydroxyl groups can reduce bacterial metabolism through reactions with thiol groups (sulfhydryl groups, -SH) that can exist within bacterial proteins, or through non-binding interactions with other protein portions, thereby inhibiting bacterial growth. Therefore, a superabsorbent polymer containing a crosslinked polymer formed by the polymerizable antimicrobial monomer represented by chemical formula 1 can exhibit antimicrobial activity against at least one of Gram-positive and Gram-negative bacteria.

[0036] Furthermore, since the superabsorbent polymer contains antibacterial monomers in the form of a crosslinked polymer in which antibacterial monomers are crosslinked together with acrylic acid monomers, the antibacterial monomers do not remain in the form of compounds within the superabsorbent polymer. Therefore, there is no risk of the antibacterial agent leaching out over time, and this gives it the characteristic of exhibiting excellent stability.

[0037] The superabsorbent polymer and its manufacturing method will be described in more detail below with specific examples of the invention.

[0038] Super water absorbent resin Specifically, the superabsorbent polymer according to one embodiment of the invention is characterized by comprising a crosslinked polymer of an acrylic acid monomer containing acidic groups, in which 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.

[0039] [ka]

[0040] In the aforementioned chemical 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 with 6 to 60 carbon atoms. A is an aromatic ring with 6 to 60 carbon atoms. Here, the arylene and aromatic ring are each independently unsubstituted or substituted with one or more substituents selected from the group consisting of hydroxyl, alkyl groups having 1 to 10 carbon atoms, and alkoxy groups having 1 to 10 carbon atoms, for example, one to five substituents.

[0041] In this case, the crosslinked polymer is formed by crosslinking the acrylic acid monomer and the polymerizable antibacterial monomer in the presence of a crosslinking agent, and has a three-dimensional network structure in which the main chain formed by the polymerization of the monomers is crosslinked by the crosslinking agent. Therefore, the polymerizable antibacterial monomer does not exist as a separate compound in the superabsorbent resin, but exists as a repeating unit constituting the main chain, and does not leach out even over time, thus maintaining the antibacterial properties of the superabsorbent resin over time.

[0042] Furthermore, the water retention capacity can be improved by further including repeating units derived from a polymerizable antimicrobial monomer in addition to the repeating units derived from the acrylic acid monomer in the crosslinked polymer of the superabsorbent resin.

[0043] On the other hand, in the above chemical formula 1, R1 to R3 may each be independently a hydrogen atom, a methyl group, or a carboxyl group.

[0044] For example, R1 through R3 may all be hydrogen; or one of R1 through R3 may be a methyl or carboxyl group, and the rest may be hydrogen.

[0045] Furthermore, in the above chemical formula 1, L may be a single bond; or unsubstituted; or a carbon-6 to carbon-20 arylene substituted with one to three substituents selected from the group consisting of hydroxy, carbon-1 to carbon-10 alkyl, and carbon-1 to carbon-10 alkoxy.

[0046] Specifically, L may be a single bond, phenylene, or naphthylene.

[0047] For example, L may be a single bond or one of the groups selected below, but is not limited to these.

[0048] [ka]

[0049] Furthermore, in the above chemical formula 1, A may be unsubstituted or a C6 to C20 aromatic ring substituted with one to three substituents selected from the group consisting of hydroxyl, C1 to C10 alkyl, and C1 to C10 alkoxy.

[0050] More specifically, A is a benzene or naphthalene ring, 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, C1-C10 alkyl, and C1-C10 alkoxy rings.

[0051] For example, A is a benzene or naphthalene ring. 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.

[0052] The polymerizable antimicrobial monomer may be represented by any one of the following chemical formulas 1-1 to 1-3.

[0053] [ka]

[0054] In the aforementioned chemical formulas 1-1 to 1-3, L' is a single bond, phenylene, or naphthylene. R is a hydroxyl group, an alkyl group having 1 to 10 carbon atoms, or an alkoxy group having 1 to 10 carbon atoms. a is an integer between 0 and 3. If a is 2 or greater, then two or more Rs are either identical or different from each other. R1 to R3 are as defined in Chemical Formula 1 above.

[0055] In the chemical formulas 1-1 to 1-3 above, L may be a single bond, 1,4-phenylene, 1,3-phenylene, or 1,6-naphthylene, but is not limited to these.

[0056] Furthermore, in the chemical formulas 1-1 to 1-3, a may be 0, 1, 2, or 3.

[0057] For example, the polymerizable antimicrobial monomer may be any one selected from the group consisting of the following, but is not limited to these.

[0058] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka] [ka]

[0059] Furthermore, the polymerizable antimicrobial monomer is contained in the crosslinked polymer in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. If the polymerizable antimicrobial monomer is contained in an amount of less than 0.1 parts by weight per 100 parts by weight of the acrylic acid monomer, it is difficult to show a sufficient antimicrobial effect. If the polymerizable antimicrobial monomer is contained in an amount of more than 1 part by weight per 100 parts by weight of the acrylic acid monomer, the hydroxyl group (OH) contained in the polymerizable antimicrobial monomer may delay the radical polymerization reaction. This may reduce the polymerizability during polymerization of the acrylic acid monomer, resulting in insufficient polymerization or a longer polymerization time.

[0060] More specifically, the polymerizable antimicrobial monomer may be included in the crosslinked 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, per 100 parts by weight of the acrylic acid monomer. In this case, in terms of improving the antimicrobial properties and absorption performance of the superabsorbent polymer, it is preferable that the polymerizable antimicrobial monomer be included in the crosslinked polymer in an amount of 0.2 to 1 part by weight per 100 parts by weight of the acrylic acid monomer.

[0061] In this case, the statement that the polymerizable antibacterial monomer is included in the crosslinked polymer in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid monomer means that, during the production of the crosslinked polymer, the polymerizable antibacterial monomer is used in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. This can be confirmed by checking the residual monomers of the superabsorbent polymer and determining whether or not antibacterial monomers are detected. However, since no antibacterial monomers are detected in the superabsorbent polymer after production, it is considered that the entire amount of antibacterial monomer used was used for polymerization with the acrylic acid monomer.

[0062] On the other hand, the acrylic acid monomer is a compound represented by the following chemical formula 2.

[0063] [Chemical formula 2] R-COOM'

[0064] In the aforementioned chemical formula 2, R is an alkenyl group with 2 to 5 carbon atoms containing an unsaturated bond. M' is a hydrogen atom, a monovalent or divalent metal, an ammonium group, or an organic amine salt.

[0065] 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.

[0066] Thus, when (meth)acrylic acid and / or its salts are used as the acrylic acid monomer, it is advantageous because it is possible to obtain a superabsorbent resin with improved water absorption.

[0067] Furthermore, the term "crosslinking agent" as used herein is used to distinguish it from additional crosslinking agents primarily used to crosslink the surface of superabsorbent polymer particles, as described later, and plays a role in crosslinking and polymerizing the unsaturated bonds of the acrylic acid monomer and polymerizable antimicrobial monomer mentioned above. The crosslinking in the above step is performed without distinction between the surface and the interior, but if the additional crosslinking step for superabsorbent polymer particles described later is performed, the surface of the particles of the final-produced superabsorbent polymer will consist mainly of a structure crosslinked by the additional crosslinking agent, and the interior will consist mainly of a structure crosslinked by the aforementioned crosslinking agent. Therefore, since the additional crosslinking agent primarily plays a role in crosslinking the surface of the superabsorbent polymer, it is considered to play the role of a surface crosslinking agent, and the aforementioned crosslinking agent is distinguished from the additional crosslinking agent and is considered to play the role of an internal crosslinking agent.

[0068] Any compound can be used as the crosslinking agent, as long as it enables the introduction of crosslinking bonds during the polymerization of the acrylic acid monomer. Non-limiting examples of the crosslinking agent include 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( Polyfunctional crosslinking agents such as 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, glycerin, or ethylene carbonate may be used alone or in combination of two or more, but are not limited thereto.

[0069] Preferably, the crosslinking agent may be a polyalkylene glycol di(meth)acrylate compound such as polyethylene glycol (meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, or polypropylene glycol (meth)acrylate.

[0070] The crosslinking polymerization of the acrylic acid monomer in the presence of such a crosslinking agent may be carried out by thermal polymerization, photopolymerization, or hybrid polymerization in the presence of a polymerization initiator, and optionally a thickener, plasticizer, preservative stabilizer, antioxidant, etc., but the specific details will be described later.

[0071] Furthermore, the superabsorbent polymer may be in the form of particles with a particle size of 850 μm or less, for example, a particle size of about 150 to 850 μm. In this case, such a particle size may be measured by the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 220.3 method. However, if the superabsorbent polymer contains a large amount of fine powder with a particle size of less than 150 μm, it may reduce the various physical properties of the superabsorbent polymer, which is undesirable.

[0072] On the other hand, the superabsorbent resin may further include a crosslinked layer formed on the crosslinked polymer by an additional crosslinking agent. Here, the crosslinked 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 crosslinked polymer within the superabsorbent resin is crosslinked by the additional crosslinking agent. This is to increase the crosslinking density on the surface of the superabsorbent resin particles, and if the superabsorbent resin further includes a structure in which at least a portion of the superabsorbent resin particles are crosslinked by the additional crosslinking agent, it will have a structure in which the crosslinking density is higher on the outside than on the inside.

[0073] As the additional crosslinking agent, any additional crosslinking agent that has been used in the production of superabsorbent polymers in the past can be used without any special restrictions. For example, the additional crosslinking agent may include 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; mono-, di-, or polyoxazolidinone compounds; or cyclic urea compounds.

[0074] Specifically, as the additional crosslinking agent, one or more, two or more, or three or more of the additional crosslinking agents mentioned above may be used. For example, ethylene carbonate-propylene carbonate (ECPC), propylene glycol, and / or glycerol carbonate may be used.

[0075] On the other hand, as described above, the superabsorbent polymer can exhibit antibacterial activity against at least one of the Gram-negative bacteria and the Gram-positive bacteria. More specifically, the superabsorbent polymer can exhibit antibacterial activity against one or more bacteria classified as Gram-positive bacteria. Alternatively, the superabsorbent polymer can exhibit antibacterial activity against one or more bacteria classified as Gram-negative bacteria. Alternatively, the superabsorbent polymer can exhibit antibacterial activity against one or more bacteria classified as Gram-negative bacteria and one or more bacteria classified as Gram-positive bacteria.

[0076] Here, "showing antibacterial activity against specific bacteria" means that after absorbing artificial urine inoculated with test bacteria into a superabsorbent polymer intended to confirm antibacterial activity, and then culturing it, the number of bacteria after 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. Specifically, this means that the bacteriostatic reduction rate (%) calculated by Formula 1 below, based on the antibacterial property evaluation described later, is 50% or more.

[0077]

number

[0078] In the above formula, C sample This is the microbial concentration (Co) in the culture medium of a superabsorbent polymer containing a bacteriostatic substance. C Reference This is the microbial concentration (Co) in the culture solution of the superabsorbent polymer of Comparative Example 1, which does not contain a bacteriostatic substance.

[0079] More preferably, "showing antibacterial activity against specific bacteria" means that the bacteriostatic reduction rate (%) calculated by formula 1 is 90% to 100%. In one example, the bacteriostatic reduction rate (%) calculated by formula 1 for the superabsorbent polymer may be 90% or more, 95% 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.

[0080] On the other hand, Gram-positive bacteria are a general term for bacteria that stain purple when stained using the Gram staining method. The cell walls of Gram-positive bacteria are composed of multiple layers of peptidoglycan, and even after staining with basic dyes such as crystal violet and then treating with ethanol, they do not decolorize and retain their purple color. Examples of bacteria classified as Gram-positive include Enterococcus faecalis, Staphylococcus aureus, Streptococcus pneumoniae, Enterococcus faecium, or Lactobacillus lactis.

[0081] Furthermore, Gram-negative bacteria are a general term for bacteria that stain red when stained using the Gram staining method. Compared to Gram-positive bacteria, they have a cell wall containing relatively small amounts of peptidoglycan, but instead have an outer membrane composed of lipid polysaccharides, lipid proteins, and other complex polymeric substances. As a result, when stained with a basic dye such as crystal violet and then treated with ethanol, decolorization occurs, and when counterstained with a red dye such as safranin, they show a red color. Examples of bacteria classified as Gram-negative include Proteus mirabilis, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, and Vibrio cholerae.

[0082] Therefore, since Gram-positive and Gram-negative bacteria can not only induce a variety of diseases upon contact, but can also cause secondary infections in severely ill patients with weakened immune systems, it is preferable to use a single antibacterial agent that exhibits antibacterial activity against both Gram-positive and Gram-negative bacteria.

[0083] Preferably, the superabsorbent polymer can exhibit antibacterial activity against both Gram-negative and Gram-positive bacteria. In this case, the Gram-negative bacteria against which the superabsorbent polymer exhibits antibacterial activity may be Proteus mirabilis or Escherichia coli, and the Gram-positive bacteria may be Enterococcus faecalis, but are not limited to these.

[0084] Specifically, the superabsorbent polymer may have a centrifugal water retention capacity (CRC) of 20 to 45 g / g in physiological saline (0.9 wt% sodium chloride aqueous solution) measured by the EDANA method WSP 241.3, after 30 minutes. If the centrifugal water retention capacity (CRC) is less than 20 g / g, the ability to retain liquid after absorption decreases, making the superabsorbent polymer unsuitable for use in sanitary products. More specifically, the superabsorbent polymer may have a centrifugal separation water 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 also be 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.

[0085] Therefore, the aforementioned superabsorbent polymer containing polymerizable antimicrobial monomers in a predetermined amount has a centrifugal separation water retention capacity (CRC) in the range of 20 to 45 g / g and can exhibit excellent antimicrobial properties.

[0086] Method for manufacturing superabsorbent resin On the other hand, the superabsorbent polymer may be manufactured by the following method.

[0087] Step 1: Prepare a monomer composition by mixing an acrylic acid monomer containing an acidic group, a polymerizable antimicrobial monomer represented by the chemical formula 1, a crosslinking agent, and a polymerization initiator. Step 2: Polymerizing the monomer composition to form a water-containing gel polymer; and The process includes the steps of drying, grinding, and classifying the water-containing gel polymer (step 3).

[0088] First, in order to produce one embodiment of a superabsorbent polymer, step 1 is performed in which an acrylic acid monomer containing an acidic group, a polymerizable antimicrobial monomer represented by the chemical formula 1, a basic substance, a crosslinking agent, and a polymerization initiator are mixed to prepare a monomer composition.

[0089] Hereinafter, a more specific description of the acrylic acid monomer, polymerizable antimicrobial monomer, and crosslinking agent will be provided by referring to the above, wherein in step 1, at least a portion of the acidic groups of the acrylic acid monomer are neutralized by mixing with a basic substance. As a result, the monomer composition may contain an acrylic acid monomer from which at least a portion of the acidic groups have been neutralized.

[0090] Here, the basic substance that can neutralize the acrylic acid monomer may be an alkaline substance such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide. The basic substance may also be added to the monomer composition in the form of an aqueous solution dissolved in water.

[0091] Furthermore, the degree of neutralization of the acrylic acid monomer, in other words, the content (mol%) of the acrylic acid monomer neutralized based on the total moles of the acrylic acid monomer used in the production of the crosslinked polymer, may be 40 to 95 mol%, 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 polymerization to proceed smoothly. Conversely, if the degree of neutralization is excessively low, not only will the absorbency of the polymer decrease significantly, but it will also exhibit properties similar to elastic rubber, making it difficult to handle.

[0092] Furthermore, in the monomer composition, the polymerizable antibacterial monomer may be used in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. If the polymerizable antibacterial monomer is used in an amount of less than 0.1 parts by weight per 100 parts by weight of the acrylic acid monomer, it may be difficult to show a sufficient antibacterial effect. If it is included in an amount of more than 1 part by weight per 100 parts by weight of the acrylic acid monomer, the radical polymerization reaction may be delayed by the hydroxyl group (OH) contained in the polymerizable antibacterial monomer, which may reduce the polymerizability of the acrylic acid monomer, resulting in insufficient polymerization or a longer polymerization time.

[0093] 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, per 100 parts by weight of the acrylic acid monomer.

[0094] Furthermore, in the monomer composition, such a crosslinking agent is included in an amount of 0.01 to 1 part by weight per 100 parts by weight of the acrylic acid monomer, and can crosslink the polymerized polymer. If the crosslinking agent content is less than 0.01 parts by weight, the improvement effect due to crosslinking will be minimal, and if the crosslinking agent content exceeds 1 part by weight, the absorption capacity of the superabsorbent polymer 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 per 100 parts by weight of the acrylic acid monomer.

[0095] Furthermore, the polymerization initiator may be appropriately selected depending on the polymerization method. When using a thermal polymerization method, a thermal polymerization initiator may be used; when using a photopolymerization method, a photopolymerization initiator may be used; and 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 with a photopolymerization method, a certain amount of heat is generated by light irradiation such as ultraviolet irradiation, and a certain amount of heat is also generated by the progress of the polymerization reaction, which is an exothermic reaction. Therefore, a thermal polymerization initiator may also be used in addition.

[0096] The aforementioned photopolymerization initiator may be any compound capable of forming radicals when exposed to light such as ultraviolet light, and its composition is not limited to this.

[0097] As the photopolymerization initiator, one or more selected from the group consisting of benzoin ether, dialkyl acetophenone, hydroxyl alkyl ketone, phenyl glyoxylate, benzyldimethyl ketal, acyl phosphine, and α-aminoketone may be used. On the other hand, specific examples of acyl phosphine include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide, and ethyl(2,4,6-trimethylbenzoyl)phenyl phosphine. A wider variety of photoinitiators are clearly described in Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007)," p. 115, and are not limited to the examples mentioned above.

[0098] The 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 monomer. If the content of such a photopolymerization initiator is less than 0.001 parts by weight, the polymerization rate may be slowed, 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 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 monomer.

[0099] Furthermore, if the polymerization initiator further includes a thermal polymerization initiator, one or more initiators selected from the group consisting of persulfate initiators, azo initiators, hydrogen peroxide, and ascorbic acid may be used as the thermal polymerization initiator. Specifically, examples of persulfate initiators include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), and ammonium persulfate ((NH4)2S2O8), while examples of azo initiators include 2,2-azobis-(2-amidinopropane)dihydrochloride and 2,2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride. Examples include dihydrochloride, 2-(carbamoylazo)isobutylonitrile, 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, and 4,4-azobis-(4-cyanovaleric acid). A wider variety of thermal polymerization initiators are clearly described in Odian's "Principle of Polymerization" (Wiley, 1981), p. 203, and are not limited to the examples mentioned above.

[0100] The thermal polymerization initiator may be present in an amount of 0.001 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. If the amount of thermal polymerization initiator is less than 0.001 parts by weight, almost no additional thermal polymerization will occur, and the effect of adding the thermal polymerization initiator may be minimal. If the amount of 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 thermal polymerization initiator may be present 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 monomer.

[0101] Furthermore, the monomer composition may further contain one or more additives, such as surfactants, thickeners, plasticizers, preservatives, and antioxidants, as needed.

[0102] Furthermore, the monomer composition described above may be prepared in the form of a solution dissolved in a solvent.

[0103] In this case, the solvent used is not limited in composition as long as it can dissolve the aforementioned components, and may be a combination of one or more selected from, for example, 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, and N,N-dimethylacetamide. The solvent may be included in an amount equal to the total content of the monomer composition, excluding the aforementioned components.

[0104] Next, step 2 is performed, in which the monomer composition is thermally polymerized or photopolymerized to form a water-containing gel polymer.

[0105] Here, the thermal polymerization and photopolymerization methods are not particularly limited in their configuration, as long as they are commonly used methods that can polymerize the monomer composition to form a hydrated gel polymer.

[0106] As an example, the photopolymerization may be carried out by irradiating with 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. Under these conditions, crosslinked polymers can be formed with better polymerization efficiency during photopolymerization.

[0107] Furthermore, when performing the photopolymerization described above, it may be carried out in a reactor equipped with a movable conveyor belt or in a stainless steel container of a certain size. However, the polymerization method described above is merely an example, and the present invention is not limited to the polymerization method described above.

[0108] Furthermore, when photopolymerization is performed in a reactor equipped with a movable conveyor belt as described above, the form of the hydrated gel polymer that is usually obtained may be a sheet-like hydrated gel polymer having the width of the belt. In this case, the thickness of the polymer sheet may vary depending on the concentration and injection rate of the monomer composition being injected, or 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 is obtained. If the monomer composition is supplied to an extent that the thickness of the sheet-like polymer is excessively thin, it is undesirable because the production efficiency is low, and if the thickness of the sheet-like polymer exceeds 5 cm, the polymerization reaction may not occur uniformly across the entire thickness due to the excessive thickness.

[0109] The water content of the water-containing gel polymer obtained from step 2 may be about 40 to about 80% by weight relative to the total weight of the water-containing gel polymer. On the other hand, throughout this specification, "water content" refers to the amount of water relative to the total weight of the water-containing gel polymer, and means the value obtained by subtracting the weight of the dry polymer from the weight of the water-containing gel polymer. Specifically, it is defined as the 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. In this case, the drying conditions are set to raise the temperature to about 180°C at room temperature and then maintain it at 180°C, and the total drying time is set to 20 minutes, including a 5 minute temperature rise stage, and the water content is measured.

[0110] On the other hand, after the production of the water-containing gel polymer, a coarse grinding step may be selectively performed to grind the produced water-containing gel polymer before the subsequent drying and grinding steps.

[0111] The aforementioned coarse grinding step is a step to increase drying efficiency in the subsequent drying step and to control the particle size of the superabsorbent polymer powder produced. The grinder used in this step is not limited in its configuration, but may include any one selected from the group of grinding equipment consisting of a vertical pulverizer, turbo cutter, turbo grinder, rotary cutter mill, cutter mill, disc mill, shred crusher, crusher, meat chopper, and disc cutter, but is not limited to the examples described above.

[0112] The aforementioned coarse grinding step may, for example, be carried out so that the particle size of the water-containing gel polymer is about 2 to about 10 mm. Grinding the water-containing gel polymer to a particle size of less than 2 mm is technically difficult due to the high water content of the water-containing gel polymer, and a phenomenon of aggregation between the ground particles may 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 will be minimal.

[0113] Next, step 3 is performed, in which the water-containing gel polymer produced in step 2 is dried, pulverized, and classified to form a superabsorbent resin containing a crosslinked polymer.

[0114] The drying method described above may be selected and used without being limited to its configuration, as long as it is one that is commonly used in the drying process of a water-containing gel polymer. Specifically, the drying step may be carried out by methods such as supplying hot air, infrared irradiation, ultra-high frequency irradiation, or ultraviolet irradiation.

[0115] Specifically, the drying may be carried out at a temperature of approximately 100 to approximately 250°C. If the drying temperature is below 100°C, the drying time will be excessively long, which may reduce the physical properties of the final superabsorbent polymer. If the drying temperature exceeds 250°C, only the polymer surface will be excessively dried, which may generate fine powder in the subsequent grinding process, and may reduce the physical properties of the final superabsorbent polymer. Therefore, preferably, the drying may 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.

[0116] The water content of the polymer after this drying stage may be about 5 to about 10% by weight.

[0117] On the other hand, a grinding step is performed after the drying step. The grinding step may be performed so that the particle size of the polymer powder, i.e., the superabsorbent resin, is about 150 to about 850 μm. The grinder used to grind to such a particle size may be, but is not limited to, a pin mill, hammer mill, screw mill, roll mill, disc mill, or jog mill.

[0118] Furthermore, after the grinding step described above, a further step may be taken to classify the ground polymer powder according to its particle size in order to control the physical properties of the superabsorbent polymer powder that will be used as the final product.

[0119] The superabsorbent polymer obtained as a result of the above process may have a fine powder form containing a crosslinked polymer in which an acrylic acid monomer and a polymerizable antibacterial monomer are crosslinked and polymerized via a crosslinking agent. Specifically, the superabsorbent polymer may have a fine powder form having a particle size of 150 to 850 μm.

[0120] Next, the process may further include a step of heat-treating the superabsorbent polymer produced in step 3 in the presence of an additional crosslinking agent to surface crosslink it. Through this step, a superabsorbent polymer can be produced that further includes a surface crosslinked layer on the crosslinked polymer, in which the crosslinked polymer is further crosslinked via the additional crosslinking agent. In this case, refer to the description of the additional crosslinking agent mentioned above.

[0121] The aforementioned 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 particles. Generally, the 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 particle surface without substantially affecting the inside of the particles. Therefore, a surface-crosslinked superabsorbent resin has a higher degree of crosslinking near the surface than inside.

[0122] Furthermore, the 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 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 may be used in an amount of 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, it is possible to produce a superabsorbent resin that exhibits excellent absorption properties.

[0123] Furthermore, there are no limitations on the configuration of the method for mixing the additional crosslinking agent with the superabsorbent resin. For example, the method may involve mixing the additional crosslinking agent and the superabsorbent resin in a reaction vessel, injecting the additional crosslinking agent into the superabsorbent resin, or continuously supplying the superabsorbent resin and the additional crosslinking agent to a continuously operating mixer for mixing.

[0124] The aforementioned surface crosslinking may be carried out by heating the superabsorbent polymer with the aforementioned additional crosslinking agent at a temperature of approximately 80 to approximately 220°C for approximately 15 to approximately 100 minutes. If the crosslinking reaction temperature is less than 80°C, the surface crosslinking reaction may not occur sufficiently, and if it exceeds 220°C, the surface crosslinking reaction may proceed excessively. Also, if the crosslinking reaction time is excessively short, less than 15 minutes, sufficient crosslinking may not occur, and if the crosslinking reaction time exceeds 100 minutes, excessive surface crosslinking may result in an excessively high crosslinking density on the particle surface, leading to a decrease in physical properties. More specifically, it may be carried out by heating at a temperature of 120°C or higher, or 140°C or higher, and 200°C or lower, or 180°C or lower, for 20 minutes or higher, or 40 minutes or higher, and 70 minutes or lower, or 60 minutes or lower.

[0125] The means for raising the temperature for the surface crosslinking reaction is not particularly limited. Heating may be performed by supplying a heat transfer medium or by directly supplying a heat source. In this case, the type of heat transfer medium that can be used may be a heated fluid such as steam, hot air, or hot oil, but the present invention is not limited thereto, and the temperature of the supplied heat transfer medium may be appropriately selected considering the type of heat transfer medium, the heating rate, and the target temperature. On the other hand, examples of directly supplied heat sources include heating by electricity and heating by gas, but are not limited to the examples described above.

[0126] Furthermore, articles containing the aforementioned biodegradable superabsorbent polymer are also provided.

[0127] The aforementioned articles may be one or more selected from the group consisting of absorbent articles, sanitary products, soil water retention agents, waterproofing materials for civil engineering, waterproofing materials for construction, seedling sheets, freshness preservatives, poultice materials, electrical insulators, oral articles, dental articles, cosmetic articles, and skin articles.

[0128] Examples of sanitary products containing the superabsorbent polymer include children's diapers, adult diapers, or sanitary napkins. Such sanitary products can have the same structure as ordinary sanitary products, except that the absorbent material contains the superabsorbent polymer described in the above example.

[0129] The following are preferred embodiments for understanding the invention. However, these embodiments are for illustrative purposes only and do not limit the invention to them.

[0130] Manufacturing Example A: Production of polymerizable antimicrobial monomer 1-1

[0131] [ka]

[0132] 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). The reactor temperature was then lowered to -78°C using an ice bath with dry ice and acetone, and acryloyl chloride (17.3 g, 19.1 mmol) was slowly added dropwise to the reaction solution for 20 minutes. After the reaction was complete, the reaction product was sufficiently diluted with ethyl acetate, and the organic layer was separated by washing with siRNA / brine. Water was removed with magnesium sulfate, and the solution passed through under reduced pressure was concentrated. After purification by hexane / ethyl acetate column chromatography, polymerizable antimicrobial monomer 1-1 (25.7 g, yield 82%) was obtained. 1 The 1H NMR spectrum is shown in Figure 1.

[0133] MS[M+H] + =164.05 1 H NMR (500MHz, 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).

[0134] Manufacturing Example B: Production of polymerizable antimicrobial monomer 1-2

[0135] [ka]

[0136] 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). The reactor temperature was then lowered to -78°C using an ice bath with dry ice and acetone, and acryloyl chloride (17.3 g, 19.1 mmol) was slowly added dropwise to the reaction solution for 20 minutes. After the reaction was complete, the reaction product was thoroughly diluted with ethyl acetate, and the organic layer was separated by washing with siRNA / brine. Water was removed with magnesium sulfate, and the solution passed through under reduced pressure was concentrated. The solution was then purified by hexane / ethyl acetate column chromatography to obtain polymerizable antimicrobial monomers 1-2 (22.3 g, 71% yield).

[0137] MS[M+H] + =164.05 1 H NMR (500MHz, 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).

[0138] Example - Production of a superabsorbent polymer composition Example 1 (Step 1) In a 3L glass container equipped with a stirrer, nitrogen inlet, and thermometer, 100g of acrylic acid, 0.25g of polyethylene glycol diacrylate (Mn=575) as a crosslinking agent, 0.00625g of phenylbis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide as a photoinitiator, 0.125g of sodium persulfate (SPS) as a thermal initiator, 100g of a 40% sodium hydroxide solution, and 0.2g of polymerizable antimicrobial monomer 1-1 produced in Production Example A were added, and nitrogen was continuously added to produce the monomer composition. At this time, the degree of neutralization of the acrylic acid and polymerizable antimicrobial monomer 1-1 was 70 mol%.

[0139] (Step 2) Subsequently, the monomer composition is placed in a stainless steel container measuring 250 mm wide, 250 mm long, and 30 mm high, and irradiated with ultraviolet light for 60 seconds in an 80°C UV chamber (irradiation dose: 10 mV / cm²). 2 After polymerization, the polymer was aged for 2 minutes to produce a sheet-like hydrated gel polymer.

[0140] (Step 3) The manufactured water-containing gel polymer was cut into 3cm x 3cm pieces and then placed in a meat chopper to crush the polymer and obtain water-containing gel particle powder (crumb) with a size of 1mm to 10mm. Subsequently, the obtained powder was spread to a thickness of approximately 30mm on stainless steel wire gauze with a pore size of 600μm and dried in a 120°C hot air oven for 11 hours. The dried polymer thus obtained was crushed using a pulverizer and classified using an ASTM standard mesh sieve to obtain a base resin with a particle size of 150 to 850μm, which was used as the superabsorbent polymer.

[0141] Example 2 In Example 1, a superabsorbent polymer was produced using the same method as in Example 1, except that 0.5 g of the polymerizable antimicrobial monomer 1-1 produced in Production Example A was used.

[0142] Example 3 In Example 1, a superabsorbent polymer was produced using the same method as in Example 1, except that 1.0 g of the polymerizable antimicrobial monomer 1-1 produced in Production Example A was used.

[0143] Example 4 A superabsorbent polymer was produced using the same method as in Example 1, except that polymerizable antimicrobial monomer 1-2 produced in Production Example B was used instead of polymerizable antimicrobial monomer 1-1 produced in Production Example A.

[0144] Example 5 A superabsorbent polymer was produced using the same method as in Example 4, except that 0.5 g of the polymerizable antimicrobial monomer 1-2 produced in Production Example B was used in Example 4.

[0145] Example 6 A superabsorbent polymer was produced using the same method as in Example 4, except that 1.0 g of the polymerizable antimicrobial monomer 1-2 produced in Production Example B was used in Example 4.

[0146] Comparative Example 1 A superabsorbent polymer was produced using the same method as in Example 1, except that polymerizable antimicrobial monomer 1-1 was not used.

[0147] Reference Example 1 In Example 1, a superabsorbent polymer was produced using the same method as in Example 1, except that 0.05 g of the polymerizable antimicrobial monomer 1-1 produced in Production Example A was used.

[0148] Experimental Example 1 The superabsorbent polymers produced in the above examples and comparative examples were evaluated for their physical properties using the following method, and the results are shown in Table 4 below.

[0149] Unless otherwise specified, all of the following physical property evaluations are performed under constant temperature and humidity conditions (23±1℃, relative humidity 50±10%), and physiological saline or salt water refers to a 0.9 wt% sodium chloride (NaCl) aqueous solution.

[0150] (1) Evaluation of antimicrobial properties against Escherichia coli After placing 2 g of the superabsorbent resin produced in the above Examples and Comparative Examples into a 250-cell culture flask, 50 ml of artificial urine inoculated with Escherichia coli (E. coli, ATCC 25922), a test microorganism, at 3000 ± 300 CFU / ml was injected. Thereafter, it was mixed for about 1 minute so that the superabsorbent resin could sufficiently absorb the artificial urine solution. The resin with the solution sufficiently absorbed showed a gel form, and this was cultured in an incubator (JEIO TECH) maintained at 35°C for 12 hours. 150 mL of 0.9 wt% NaCl solution was added to the cultured sample and shaken for about 1 minute, and this diluted solution was smeared on an agar medium plate. Thereafter, serial dilution was performed so that colony counting became possible, and 0.9 wt% NaCl solution was used in this process. The bacteriostatic performance was calculated for the microbial concentration (Co, CFU / mL) at the initial concentration after considering the dilution concentration, and the bacteriostatic reduction rate (%) of Escherichia coli (E. coli, ATCC 25922) was calculated using the following formula 1, and the results are shown in Table 4 below.

[0151] [Number]

[0152] In the above formula, C sample is the microbial concentration (Co) in the culture solution of the superabsorbent resin containing the bacteriostatic substance, C Reference is the microbial concentration (Co) in the culture solution of the superabsorbent resin of Comparative Example 1 that does not contain the bacteriostatic substance.

[0153] At this time, the artificial urine used for the antibacterial property evaluation was produced as follows.

[0154] First, the reagents listed in Table 1 were placed in a 1000 mL flask according to their specified weights, and water was added up to the 1000 mL mark. The mixture was then mixed to prepare the Stock solution. Next, the reagents listed in Table 2 were placed in a 100 mL flask according to their specified weights, and water was added up to the 20 mL mark. The mixture was then mixed to prepare the Cationic solution. Finally, the reagents listed in Table 3 were placed in a 100 mL flask according to their specified weights, and water was added up to the 100 mL mark. The mixture was then mixed to prepare the Urea / glucose solution.

[0155] Next, the prepared stock solution and Cationic solution were sterilized using an autoclaver at 120°C for 15 minutes, then cooled completely to room temperature. The prepared urea / glucose solution was then purified by removing impurities using a 0.22 μm syringe filter (Hydrophilic, manufactured by Sartoriusstedim).

[0156] Subsequently, 940 mL of stock solution, 10 mL of cationic solution, and 50 mL of urea / glucose solution were thoroughly mixed to prepare artificial urine. The prepared artificial urine can be used for two weeks under normal refrigeration conditions, and artificial urine older than two weeks should not be used in the experiment.

[0157] [Table 1]

[0158] [Table 2]

[0159] [Table 3]

[0160] (2)Centrifuge Retention Capacity (CRC) According to the European Disposables and Nonwovens Association (EDANA) standard EDANAWSP 241.3, the centrifugal separation water retention capacity of each example and comparative example of the superabsorbent polymer was measured based on the absorption ratio under no load.

[0161] Specifically, superabsorbent polymer W0 (g) (approximately 0.2g) was uniformly placed in a nonwoven fabric envelope, sealed, and then immersed in physiological saline (0.9 wt% sodium chloride aqueous solution) at room temperature. After 30 minutes, the envelope was drained for 3 minutes under 250G conditions using a centrifuge, and the weight of the envelope W2 (g) was measured. The same procedure was also performed without the polymer, and the weight W1 (g) at that time was measured. Using the obtained masses, the CRC (g / g) was calculated using the following formula, and the results are shown in Table 4 below.

[0162] [Formula 2] CRC(g / g)={[W2(g)-W1(g)] / W0(g)}-1

[0163] In the above formula 2, W0(g) is the initial weight (g) of the superabsorbent polymer. W1(g) is the weight of the envelope measured after immersing it in physiological saline solution for 30 minutes to allow it to absorb the water, and then dehydrating it using a centrifuge at 250G for 3 minutes, without using a superabsorbent polymer. W2(g) is the weight of the envelope, including the superabsorbent polymer, after immersing it in physiological saline solution at room temperature for 30 minutes to allow it to absorb the solution, then dehydrating it using a centrifuge at 250G for 3 minutes.

[0164] [Table 4]

[0165] Referring to Table 4 above, it can be confirmed that the superabsorbent polymers of the examples, compared to the superabsorbent polymer of Comparative Example 1, which did not use a polymerizable antibacterial monomer during polymerization of the acrylic acid monomer, and the superabsorbent polymer of Reference Example 1, which used 0.05 parts by weight per 100 parts by weight of acrylic acid monomer, exhibit improved centrifugal separation water retention capacity (CRC) and excellent antibacterial activity against Escherichia coli, a Gram-negative bacterium.

Claims

1. A crosslinked polymer comprising an acrylic acid monomer containing an acidic group, in which at least a portion of the acidic group is neutralized; a polymerizable antimicrobial monomer represented by the following chemical formula 1-1; and a crosslinking agent, The polymerizable antimicrobial monomer is contained in the crosslinked polymer in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. Super absorbent resin. 【Chemistry 1】 In the above chemical formula 1-1, L' is a single bond, R １ R ３ It is hydrogen.

2. The polymerizable antimicrobial monomer is one selected from the group consisting of the following: The superabsorbent resin according to claim 1. 【Chemistry 2】

3. The polymerizable antimicrobial monomer is contained in the crosslinked polymer in an amount of 0.2 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. The superabsorbent resin according to claim 1.

4. The superabsorbent polymer exhibits antibacterial activity against at least one of Gram-negative and Gram-positive bacteria. The superabsorbent resin according to claim 1.

5. The aforementioned Gram-negative bacteria are Proteus mirabilis or Escherichia coli. The aforementioned Gram-positive bacterium is Enterococcus faecalis. The superabsorbent resin according to claim 4.

6. The superabsorbent polymer has a water retention capacity (CRC) of 20 to 45 g / g after 30 minutes of centrifugation in physiological saline (0.9 wt% sodium chloride aqueous solution), as measured by the EDANA method WSP 241.

3. The superabsorbent resin according to claim 1.

7. Step 1: Prepare a monomer composition by mixing an acrylic acid monomer containing an acidic group, a polymerizable antimicrobial monomer represented by the following chemical formula 1-1, a crosslinking agent, and a polymerization initiator; Step 2: Polymerizing the monomer composition to form a water-containing gel polymer; and Step 3 includes drying, grinding, and classifying the water-containing gel polymer. The polymerizable antibacterial monomer is used in an amount of 0.1 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. A method for producing a superabsorbent resin according to claim 1. 【Transformation 3】 In the above chemical formula 1-1, L' is a single bond, R １ R ３ It is hydrogen.

8. The polymerizable antibacterial monomer is used in an amount of 0.2 to 1 part by weight per 100 parts by weight of the acrylic acid monomer. A method for producing a superabsorbent resin according to claim 7.

9. An article comprising the superabsorbent polymer described in any one of claims 1 to 6.

10. The article according to claim 9, wherein the article is one or more selected from the group consisting of water-absorbing articles, sanitary products, soil water retention agents, civil engineering waterproofing materials, building waterproofing materials, seedling sheets, freshness preservatives, poultice materials, electrical insulators, oral articles, dental articles, cosmetic articles, and skin articles.

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