KR20230038090A - Super absorbent polymer and preparation method thereof - Google Patents

Abstract

The present invention relates to a superabsorbent polymer and a manufacturing method thereof, and more specifically, provides a superabsorbent polymer capable of exhibiting improved bacterial growth inhibiting properties without deterioration in water retention capacity of the superabsorbent polymer, and a manufacturing method thereof. Provided is the superabsorbent polymer contains a base resin comprising an acrylic acid-based monomer containing an acidic group at least a portion of which is neutralized, a polymerizable antibacterial monomer represented by a chemical formula 1, and a crosslinked polymer in which a first crosslinking agent is polymerized, wherein at least a portion of the base resin is surface-treated by the second crosslinking agent.

Description

Super absorbent polymer and its manufacturing method {SUPER ABSORBENT POLYMER AND PREPARATION METHOD THEREOF}

The present invention relates to a superabsorbent polymer and a method for preparing the superabsorbent polymer, which exhibits improved bacterial growth inhibiting properties without deteriorating the absorbent performance of the superabsorbent polymer.

Super Absorbent Polymer (SAP) is a synthetic high-molecular substance that has the ability to absorb 500 to 1,000 times its own weight in moisture. Material), etc., are named by different names. The superabsorbent polymer as described above has begun to be put into practical use as a sanitary tool, and now, in addition to sanitary products such as paper diapers for children, soil remediation agents for gardening, water retention materials for civil engineering and construction, sheets for raising seedlings, freshness retainers in the field of food distribution, and It is widely used as a material for steaming or in the field of electrical insulation.

In particular, superabsorbent polymers are most widely applied to sanitary products or disposable absorbent products such as paper diapers for children or adult diapers. Therefore, when bacteria proliferate in such sanitary products and disposable absorbent products, not only various diseases can be caused, but also secondary odors can be caused, which is a problem. Accordingly, attempts have been made to introduce various bacterial growth inhibiting components or deodorizing or antibacterial functional components such as superabsorbent polymers.

However, in introducing an antibacterial agent that inhibits bacterial growth into the superabsorbent polymer, the basic physical properties of the superabsorbent polymer are deteriorated while exhibiting excellent bacterial growth inhibitory properties and deodorizing properties, harmless to the human body, and satisfying economic feasibility. It was not so easy to select and introduce an antimicrobial component that is not required.

Accordingly, there is a continuous demand for the development of a super absorbent polymer-related technology capable of suppressing the growth of excellent bacteria without deterioration of the basic physical properties of the super absorbent polymer.

Accordingly, an object of the present invention is to provide a super absorbent polymer capable of exhibiting improved bacterial growth inhibiting properties without deteriorating the absorption performance of the super absorbent polymer and a method for preparing the same.

According to one embodiment of the present invention,

A base resin comprising an acrylic acid-based monomer containing an acidic group and at least a portion of the acidic group neutralized, a polymerizable antibacterial monomer represented by the following Chemical Formula 1, and a crosslinked polymer in which a first crosslinking agent is polymerized,

At least a portion of the base resin is surface-treated by the second crosslinking agent,

A superabsorbent polymer is provided:

[Formula 1]

In Formula 1,

R ₁ to R ₃ are each independently hydrogen or methyl;

R ₄ is hydrogen or substituted or unsubstituted alkyl having 1 to 20 carbon atoms;

L ₁ is a substituted or unsubstituted alkylene having 1 to 10 carbon atoms.

According to another embodiment of the invention,

Forming a water-containing gel polymer by crosslinking polymerization of an acrylic acid-based monomer containing an acidic group and at least partially neutralizing the acidic group and a polymerizable antibacterial monomer represented by Formula 1 in the presence of a first crosslinking agent and a polymerization initiator;

drying, pulverizing, and classifying the water-containing gel polymer to form a base resin including a crosslinked polymer; and

In the presence of a second cross-linking agent, heat-treating the base resin to surface cross-link,

A method for producing a superabsorbent polymer is provided:

[Formula 1]

In Formula 1,

R ₁ to R ₃ are each independently hydrogen or methyl;

R ₄ is hydrogen or substituted or unsubstituted alkyl having 1 to 20 carbon atoms;

L ₁ is a substituted or unsubstituted alkylene having 1 to 10 carbon atoms.

In addition, according to another embodiment of the present invention, a sanitary product including the superabsorbent polymer described above is provided.

The superabsorbent polymer of the present invention may exhibit antibacterial properties that inhibit the proliferation of bacteria that are harmful to the human body and may cause secondary odor.

Specifically, when the superabsorbent polymer is prepared using a polymerizable antibacterial monomer having a specific structure when forming a crosslinked polymer, it exhibits antibacterial properties against at least one of Gram-negative bacteria, while using another antibacterial agent. Unlike, it can maintain excellent water retention ability, and since the antibacterial monomer used does not remain in the resin, there is no problem of human body stability due to the elution of the antibacterial agent.

Therefore, the superabsorbent polymer can be very preferably applied not only to children's diapers but also to various sanitary products such as adult diapers requiring antibacterial properties against bacteria.

Terms used in this specification are only used to describe exemplary embodiments, and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, terms such as "comprise", "comprise" or "having" are intended to indicate that there is an embodied feature, step, component, or combination thereof, but one or more other features or steps; It should be understood that the presence or addition of components, or combinations thereof, is not previously excluded.

Also, in the present invention, when each layer or element is referred to as being formed “on” or “on” each layer or element, it means that each layer or element is formed directly on each layer or element, or other This means that layers or elements may be additionally formed between each layer or on the object or substrate.

Since the present invention can have various changes and various forms, specific embodiments will be exemplified and described in detail below. However, it should be understood that this is not intended to limit the present invention to the specific disclosed form, and includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

In addition, technical terms used herein are only for referring to specific embodiments and are not intended to limit the present invention. And, as used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite.

Meanwhile, the term "(meth)acrylate" used herein includes both acrylate and methacrylate.

In addition, in the present 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 exemplary embodiment, the alkyl group has 1 to 6 carbon atoms. 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-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, 2-ethylbutyl, Heptyl, n-heptyl, 1-methylhexyl, cyclopentylmethyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2, 2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 2-methylpentyl, 4-methylhexyl, 5-methylhexyl, etc., but is not limited thereto. In addition, in the present specification, the description of the above-described alkyl group may be applied except that the alkylene is a divalent group.

The term "polymer" or "polymer" used in the specification of the present invention refers to a state in which acrylic acid-based monomers are polymerized, and may cover all ranges of moisture content or particle size. Among the polymers, polymers in a state after polymerization and before drying and having a moisture content (moisture content) of about 40% by weight or more may be referred to as hydrogel polymers, and particles obtained by pulverizing and drying such hydrogel polymers may be referred to as crosslinked polymers. there is.

Also, the term "superabsorbent polymer particles" refers to a particulate material including a crosslinked polymer obtained by polymerizing an acrylic acid-based monomer containing acidic groups and at least partially neutralizing the acidic groups and crosslinking by a first crosslinking agent.

In addition, the term “superabsorbent polymer” refers to a crosslinked polymer obtained by polymerizing an acrylic acid-based monomer containing an acidic group and at least a portion of the acidic group neutralized, or a powder composed of superabsorbent polymer particles in which the crosslinked polymer is pulverized, depending on the context. ) form, or covers all of the crosslinked polymers or base resins in a state suitable for commercialization through additional processes such as surface crosslinking, fine powder reassembly, drying, pulverization, classification, etc. used to do

In order to secure antibacterial and deodorant properties in conventional superabsorbent polymers, a metal compound having an antibacterial function or an organic compound containing a cation or alcohol functional group was introduced in the form of an additive. However, in this case, the safety of the superabsorbent polymer is deteriorated, basic physical properties such as absorption characteristics are deteriorated, and there are problems of persistence of antibacterial properties and leakage of antibacterial substances.

As an example, an attempt has been made to introduce an antibacterial component containing an antibacterial metal ion such as silver, copper, copper, or zinc into a superabsorbent polymer. The antibacterial metal ion-containing component destroys the cell walls of microorganisms such as bacteria and destroys bacteria having enzymes that may cause odors in the superabsorbent polymer, thereby imparting deodorizing properties. However, in the case of the metal ion-containing component, it is classified as a biocide (BIOCIDE) material that can kill even microorganisms beneficial to the human body. As a result, when the superabsorbent polymer is applied to sanitary products such as diapers for children or adults, the introduction of the metal ion-containing antibacterial component is excluded as much as possible.

In the past, when introducing an antibacterial agent that inhibits bacterial growth into the superabsorbent polymer, a method of mixing a small amount of the antibacterial agent with the superabsorbent polymer was mainly applied. However, it is true that when such a mixing method is applied, it is difficult to uniformly maintain the bacteria growth inhibitory properties over time. Moreover, in the case of this mixing method, in the process of mixing the superabsorbent polymer and the antibacterial agent, non-uniform coating and detachment of the antimicrobial agent component may occur, and there are also disadvantages such as the need to install new equipment for the mixing. .

In addition, there are so many different types of bacteria (germs) that more than 5,000 have been identified. Specifically, bacteria have various cell shapes such as ball, rod, spiral, etc., and the degree of oxygen demand is also different for each bacteria, so they are divided into aerobic bacteria, facultative bacteria and anaerobic bacteria. Therefore, it has not been easy for one type of antibacterial agent to have a physical/chemical mechanism that can damage the cell membrane/cell wall or denature the protein of various bacteria.

However, when a superabsorbent polymer is prepared by polymerizing a monomer containing a secondary amine having a specific structure together with an acrylic acid-based monomer, it exhibits a certain level of absorption performance while exhibiting antibacterial activity against at least one of Gram-negative bacteria. It was confirmed that it could represent, and the present invention was completed. When the amino group of the polymerizable antibacterial monomer represented by Formula 1 is positively charged by combining with a proton, the interaction with the cell wall of the microorganism increases, and the alkyl group corresponding to the pendant group destabilizes the cell wall of the microorganism, It exhibits antibacterial properties by inhibiting the growth of Specifically, since cell membranes of most bacteria are negatively charged, most antibacterial substances have a positive charge. When a hydrogen cation (proton) is bonded to the amine of the compound represented by Formula 1 to exhibit cationic properties, it can interact with bacterial cell membranes, so the compound represented by Formula 1 has antibacterial properties.

Moreover, since the superabsorbent polymer includes the antibacterial monomer in the form of a crosslinked polymer crosslinked with the acrylic acid-based monomer, the antibacterial monomer does not remain in the form of a compound in the superabsorbent polymer, so that the antibacterial agent can be eluted over time. There is no concern, and accordingly, it has the characteristic of showing excellent stability.

Hereinafter, a superabsorbent polymer and a manufacturing method thereof will be described in more detail according to specific embodiments of the present invention.

super absorbent polymer

Specifically, the superabsorbent polymer according to one embodiment of the invention,

A base resin including an acrylic acid-based monomer containing an acidic group and at least a portion of the acidic group neutralized, a polymerizable antibacterial monomer represented by Formula 1 below, and a crosslinked polymer in which the first crosslinking agent is polymerized, Characterized in that at least a part of the base resin is surface treated:

[Formula 1]

In Formula 1,

R ₁ to R ₃ are each independently hydrogen or methyl;

R ₄ is hydrogen or substituted or unsubstituted alkyl having 1 to 20 carbon atoms;

L ₁ is a substituted or unsubstituted alkylene having 1 to 10 carbon atoms.

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

In Formula 1, preferably, each of R ₁ and R ₂ is hydrogen, and R ₃ may be methyl.

Also preferably, R ₄ may be substituted or unsubstituted alkyl having 1 to 10 carbon atoms, more preferably, R ₄ may be tertbutyl. In general, as the number of carbon atoms at the R ₄ position increases, affinity with the bilayer of the outer cell wall of microorganisms increases, thereby exhibiting strong antibacterial activity. In the case of alkyl having 8 or more carbon atoms, it is important to have an appropriate length because it can exhibit strong bactericidal activity even in water.

When the terminal of the antimicrobial compound is a tertiary amine, as described above, it can play a role capable of interacting with the outer cell wall of microorganisms. However, instead of increasing the inductive effect of electrons, the interaction between the cell membrane and the positive charge is negatively affected due to the steric effect. On the other hand, the terminal of the compound represented by Formula 1 is a secondary amine. In this case, since the steric effect is reduced, it is more easily bonded to a proton and becomes positively charged, so it can exhibit stronger interaction with the cell wall of a negatively charged microorganism. Therefore, even when R ₄ is tertbutyl having a relatively small number of carbon atoms, excellent antibacterial performance can be exhibited.

Preferably, L ₁ may be substituted or unsubstituted alkylene having 1 to 5 carbon atoms, and more preferably, L ₁ may be ethylene.

As an example, the polymerizable antibacterial monomer may be a compound represented by Formula 1-1:

[Formula 1-1]

.

.

Meanwhile, the polymerizable antibacterial monomer is included in an amount of 5 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the acrylic acid-based monomer in the crosslinked polymer. When the polymerizable antibacterial monomer is included in less than 5 parts by weight relative to 100 parts by weight of the acrylic acid-based monomer, it is difficult to exhibit sufficient antibacterial effect, and when included in an amount greater than 20 parts by weight relative to 100 parts by weight of the acrylic acid-based monomer, the superabsorbent polymer Absorption performance may decrease, and the polymerization rate of the superabsorbent polymer may decrease.

More specifically, the polymerizable antibacterial monomer is 5 parts by weight or more, 5.5 parts by weight or more, or 6 parts by weight or more, 20 parts by weight or less, 15 parts by weight or less, 12 parts by weight or less, based on 100 parts by weight of the acrylic acid-based monomer in the crosslinked polymer. It may be included in an amount of less than 10 parts by weight, less than 9 parts by weight, or less than 8 parts by weight. At this time, in terms of maintaining the water absorption performance of the super absorbent polymer, specifically, the centrifugal water retention capacity, the polymerizable antimicrobial monomer in the crosslinked polymer is preferably included in an amount of 5 to 10 parts by weight based on 100 parts by weight of the acrylic acid monomer.

At this time, the meaning that the polymerizable antimicrobial monomer is included in an amount of 5 to 20 parts by weight based on 100 parts by weight of the acrylic acid-based monomer in the crosslinked polymer, compared to 100 parts by weight of the acrylic acid-based monomer when preparing the crosslinked polymer It means that it is used in an amount of 5 to 20 parts by weight. This can be confirmed through whether the antimicrobial monomer is detected when checking the residual monomer of the superabsorbent polymer. Since the antibacterial monomer is not detected after manufacturing the superabsorbent polymer, all of the antibacterial monomer used is used for polymerization with the acrylic acid-based monomer. can be seen as having been

For example, the polymerizable antibacterial monomer represented by Chemical Formula 1-1 exhibits antibacterial activity against specific bacteria. Here, the meaning of "showing antibacterial activity to a specific bacterium" means that the material to be checked for antibacterial activity absorbs artificial urine inoculated with the test bacteria, and then the number of bacteria after culturing it is the material that does not contain the antibacterial substance. This means that the test bacteria absorbed the inoculated artificial urine and then significantly decreased compared to the number of reference bacteria after culturing it. It means that the antibacterial property is excellent.

[Equation 1]

Bacterial growth inhibition rate (%) = [(OD _Reference - OD _Sample ) / OD _Reference ] * 100

In the above formula, OD _Reference is absorbance in a culture medium not containing a bacteriostatic substance, and OD _sample is absorbance in a culture medium containing a bacteriostatic substance.

Or "shows antibacterial activity to specific bacteria" means that the bacteriostatic reduction rate (%) calculated by Equation 2 below is 45% or more.

[Equation 2]

Bacteriostatic reduction rate (%) = (1 - C _sample / C _Reference ) * 100

In the above formula,

C _sample is the microbial concentration (Co) in the culture medium of the substance containing the bacteriostatic substance,

C _Reference is the concentration of microorganisms (Co) in a culture of a substance that does not contain bacteriostatic substances.

More preferably, the "shows antibacterial activity to specific bacteria" means that the bacteriostatic reduction rate (%) calculated by Equation 2 is 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, or 99% or more.

Specifically, the polymerizable antibacterial monomer represented by Chemical Formula 1-1 exhibits antibacterial activity against Escherichia coli (E. coli) or Proteus mirabilis (P. mirabilis). The polymerizable antibacterial monomer represented by Chemical Formula 1-1 is 3 parts by weight or more and 7 parts by weight or less relative to 100 parts by weight of the superabsorbent polymer. ) exhibits antibacterial properties.

Meanwhile, the acrylic acid-based monomer is a compound represented by Formula 1 below:

[Formula 2]

R-COOM'

In Formula 2,

R is an alkyl group having 2 to 5 carbon atoms including an unsaturated bond,

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

Preferably, the monomer may be at least one 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.

As such, when (meth)acrylic acid and/or a salt thereof are used as the acrylic acid-based monomer, it is advantageous in that a superabsorbent polymer having improved water absorbency can be obtained.

Here, the acrylic acid-based monomer may have an acidic group and at least a portion of the acidic group may be neutralized. Preferably, those obtained by partially neutralizing the monomers with alkali substances such as sodium hydroxide, potassium hydroxide, and ammonium hydroxide may be used. In this case, the degree of neutralization of the acrylic acid-based monomer may be 40 to 95 mol%, or 40 to 80 mol%, or 45 to 75 mol%. The range of the degree of neutralization may be adjusted according to final physical properties. However, if the degree of neutralization is too high, neutralized monomers may precipitate out, making it difficult for the polymerization to proceed smoothly. Conversely, if the degree of neutralization is too low, the absorbency of the polymer is greatly reduced, and it may exhibit properties such as elastic rubber that are difficult to handle. there is.

In addition, the term 'first cross-linking agent' used herein is a term used to differentiate from the second cross-linking agent for cross-linking the surface of the superabsorbent polymer particles, which will be described later. It plays a role in polymerization by bridging unsaturated bonds. Crosslinking in the above step proceeds regardless of surface or internal, but when the surface crosslinking process of the superabsorbent polymer particles described later proceeds, the surface of the finally prepared superabsorbent polymer particle has a structure crosslinked by the second crosslinking agent, , The inside is composed of a structure crosslinked by the first crosslinking agent. Therefore, since the second crosslinking agent mainly serves to crosslink the surface of the superabsorbent polymer, it can be seen that it serves as a surface crosslinking agent, and the first crosslinking agent is distinguished from the second crosslinking agent and serves as an internal crosslinking agent. .

As the first crosslinking agent, any compound may be used as long as it enables the introduction of crosslinking bonds during polymerization of the acrylic acid-based monomer. As a non-limiting example, the first 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 Acrylates, hexanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipentaerythritol pentaacrylate, glycerin Multifunctional crosslinking agents such as tri(meth)acrylate, pentaerythol tetraacrylate, triarylamine, ethylene glycol diglycidyl ether, propylene glycol, glycerin, or ethylene carbonate may be used alone or in combination of two or more, It is not limited thereto.

Preferably, the first crosslinking agent is polyethylene glycol (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, or polypropylene glycol (meth) acrylate. An alkylene glycol di(meth)acrylate-based compound may be used.

The cross-linking polymerization of the acrylic acid-based monomer in the presence of the first cross-linking agent may be carried out by thermal polymerization, photo-polymerization or co-polymerization in the presence of a polymerization initiator and, if necessary, a thickener, a plasticizer, a storage stabilizer, an antioxidant, and the like. However, the specific details will be described later.

Meanwhile, the superabsorbent polymer includes a surface crosslinking layer formed on the crosslinked polymer by further crosslinking the base resin including the crosslinked polymer with a second crosslinking agent, and the surface crosslinking layer is at least a portion of the base resin. includes surface treatment. This is to increase the surface cross-linking density of the super-absorbent polymer particles. As described above, when the super-absorbent polymer particles further include a surface cross-linking layer, they have a structure in which the external cross-linking density is higher than the internal ones.

As the second crosslinking agent, any second crosslinking agent previously used in the manufacture of superabsorbent polymers may be used without particular limitation. For example, the second crosslinking agent is ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, 2 - 1 selected from the group consisting of methyl-1,3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, tripropylene glycol and glycerol more than one polyol; At least one carbonate-based compound 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; mono-, di- or polyoxazolidinone compounds; one or more polyvalent metal salts of metal-containing sulfates such as aluminum sulfate, or carboxylates; or cyclic urea compounds; etc. may be included.

Specifically, one or more, two or more, or three or more of the aforementioned second cross-linking agents may be used as the second cross-linking agent, and for example, ethylene carbonate, propylene glycol, and/or aluminum sulfate may be used. .

In addition, the superabsorbent polymer may be in the form of particles having a particle size of 850 μm or less, for example, about 150 to 850 μm. At this time, this particle diameter may be measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 220.3 method. Here, when the super absorbent polymer contains a large amount of fine powder having a particle size of less than 150 μm, it is not preferable because the physical properties of the super absorbent polymer may be deteriorated.

Meanwhile, as described above, the superabsorbent polymer may exhibit antibacterial activity against at least one of the Gram-negative bacteria. More specifically, the superabsorbent polymer may exhibit antibacterial activity against one or more types of bacteria classified as Gram-negative bacteria.

The Gram-negative bacteria are a generic term for bacteria that are stained red when stained by the Gram staining method, and instead of having a cell wall with a relatively small amount of peptidoglycan compared to Gram-positive bacteria, lipopolysaccharides, lipoproteins, and other complex macromolecules It has an outer membrane composed of 　. Accordingly, when dyed with a basic dye such as crystal violet and then treated with ethanol, discoloration occurs, and when counterstained with a red dye such as safranin, a red color is displayed. Bacteria classified as Gram-negative bacteria include Proteus mirabilis, Escherichia coli, Salmonella typhi, Pseudomonas aeruginosa, and Vibrio cholerae.

Therefore, the gram-negative bacteria can cause various diseases upon contact, and can also cause secondary infection in severely ill patients with low immunity. desirable. In this case, the gram-negative bacteria exhibiting antibacterial properties of the superabsorbent polymer may be Escherichia coli or Proteus mirabilis, but is not limited thereto.

Meanwhile, the superabsorbent polymer may have a centrifugal water retention capacity (CRC) of 20 g/g or more and 45 g/g or less for 30 minutes in physiological saline (0.9 wt% aqueous sodium chloride solution) measured according to WSP 241.3 of the EDANA method. . If the centrifugal water retention capacity (CRC) is less than 20 g/g, the ability to absorb and retain liquid is deteriorated, making the superabsorbent polymer unsuitable for application to sanitary products. More specifically, the superabsorbent polymer has a centrifugal retention capacity (CRC) of 20 g/g or more, 25 g/g or more, 30 g/g or more, 35 g/g or more, or 35.6 g/g or more. , 45 g/g or less, 43 g/g or less, 41 g/g or less, 40 g/g or less, 38 g/g or less, or 37.4 g/g or less.

Accordingly, the above-described superabsorbent polymer containing a predetermined amount of a polymerizable antibacterial monomer in a crosslinked polymer may exhibit excellent antibacterial properties while having a centrifugal water retention capacity (CRC) of 20 to 45 g/g.

Manufacturing method of superabsorbent polymer

Meanwhile, the superabsorbent polymer may be prepared by the following manufacturing method:

Forming a water-containing gel polymer by crosslinking and polymerizing an acrylic acid-based monomer containing an acidic group and at least partially neutralizing the acidic group and a polymerizable antibacterial monomer represented by Formula 1 in the presence of a first crosslinking agent and a polymerization initiator;

drying, pulverizing, and classifying the water-containing gel polymer to form a base resin including a crosslinked polymer; and

and heat-treating the base resin in the presence of a second cross-linking agent to cross-link the surface.

First, step 1 is a step of forming a water-containing gel polymer by cross-linking and polymerizing an acrylic acid-based monomer and a polymerizable antibacterial monomer in the presence of a first cross-linking agent and a polymerization initiator, in which at least a part of the acidic group is neutralized.

The step may include preparing a monomer composition by mixing the acrylic acid-based monomer, the first crosslinking agent, and a polymerization initiator, and forming a hydrogel polymer by thermally or photopolymerizing the monomer composition. At this time, the description of the acrylic acid-based monomer, the polymerizable antibacterial monomer and the first crosslinking agent refers to the above bar.

In the monomer composition, the first crosslinking agent is included in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the acrylic acid monomer, so that the polymerized polymer may be crosslinked. If the content of the first crosslinking agent is less than 0.01 parts by weight, the improvement effect due to crosslinking is insignificant, and if the content of the first crosslinking agent exceeds 1 part by weight, the absorption capacity of the superabsorbent polymer may decrease. More specifically, the first crosslinking agent may be included in an amount of 0.05 parts by weight or more, or 0.1 parts by weight or more, and 0.5 parts by weight or less, or 0.3 parts by weight or less, based on 100 parts by weight of the acrylic acid-based monomer.

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

As the photopolymerization initiator, any compound capable of forming radicals by light such as ultraviolet light may be used without limitation in its configuration.

Examples of the photopolymerization initiator include benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketal. Ketal), acyl phosphine, and alpha-aminoketone (α-aminoketone) may be used at least one selected from the group consisting of. On the other hand, specific examples of acylphosphine include diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, ethyl (2,4,6- Trimethylbenzoyl) phenylphosphinate etc. are mentioned. More various photoinitiators are well described in "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007)" p115, a book by Reinhold Schwalm, and are not limited to the above examples.

The photopolymerization initiator may be included in an amount of 0.001 to 1 part by weight based on 100 parts by weight of the acrylic acid-based monomer. When the content of the photopolymerization initiator is less than 0.001 parts by weight, the polymerization rate may be slowed down, and when the content of the photopolymerization initiator exceeds 1 part by weight, the molecular weight of the superabsorbent polymer may be small and physical properties may become non-uniform. More specifically, the photopolymerization initiator is included in an amount of 0.005 parts by weight or more, or 0.01 parts by weight or more, or 0.1 parts by weight or more, and 0.5 parts by weight or less, or 0.3 parts by weight or less, based on 100 parts by weight of the acrylic acid monomer. can

In addition, when a thermal polymerization initiator is further included as the polymerization initiator, at least one selected from the group consisting of a persulfate-based initiator, an azo-based initiator, hydrogen peroxide, and ascorbic acid may be used as the thermal polymerization initiator. Specifically, examples of the persulfate-based initiator include sodium persulfate (Na2S2O8), potassium persulfate (K2S2O8), ammonium persulfate ((NH4)2S2O8), and the like. Examples of initiators include 2,2-azobis(2-amidinopropane) dihydrochloride, 2,2-azobis-(N,N-dimethylene)isobu 2,2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride, 2-(carbamoylazo)isobutylonitril, 2,2-azobis [2-(2-imidazolin-2-yl)propane] dihydrochloride (2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride), 4,4-azobis-( 4-cyanovaleric acid) (4,4-azobis-(4-cyanovaleric acid)) and the like. For more diverse thermal polymerization initiators, see Odian's 'Principle of Polymerization (Wiley, 1981)', p. 203, and is not limited to the examples described above.

The thermal polymerization initiator may be included in an amount of 0.001 to 1 part by weight based on 100 parts by weight of the acrylic acid-based monomer. If the content of the thermal polymerization initiator is less than 0.001 part by weight, additional thermal polymerization hardly occurs, so the effect of adding the thermal polymerization initiator may be insignificant, and if the content of the thermal polymerization initiator exceeds 1 part by weight, the molecular weight of the super absorbent polymer is small. Physical properties may be non-uniform. More specifically, the 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, or 0.1 parts by weight or more, and 0.5 parts by weight or less, or 0.3 parts by weight or less, based on 100 parts by weight of the acrylic acid monomer. there is.

In addition to the polymerization initiator, one or more additives such as a surfactant, a thickener, a plasticizer, a storage stabilizer, and an antioxidant may be further included as needed during crosslinking polymerization.

A monomer composition comprising the above-described acrylic acid-based monomer, a polymerizable antibacterial monomer and a first crosslinking agent, and optionally a photopolymerization initiator and an additive may be prepared in the form of a solution dissolved in a solvent.

The solvent that can be used at this time can be used without limitation in composition as long as it can dissolve the above-mentioned components, and 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 At least one selected from ethyl ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate, and N, N-dimethylacetamide may be used in combination. The solvent may be included in a residual amount excluding the components described above with respect to the total content of the monomer composition.

In addition, in the case of using a water-soluble solvent such as water as the solvent and using a terpene-based compound that is insoluble in water as the polymerizable antibacterial monomer, 10 parts by weight based on 100 parts by weight of the polymerizable antibacterial monomer to increase the solubility A surfactant may be additionally added in an amount equal to or less than a part.

On the other hand, the method of forming a hydrogel polymer by thermal polymerization or photopolymerization of such a monomer composition is also not particularly limited as long as it is a commonly used polymerization method.

Specifically, the photopolymerization may 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. Under the above conditions, it is possible to form a crosslinked polymer with better polymerization efficiency during photopolymerization.

In addition, when the photopolymerization is performed, it may be performed in a reactor equipped with a movable conveyor belt or in a container made of stainless material of a certain size, but the above-described polymerization method is an example, and the present invention is not limited to the above-described polymerization method. don't

In addition, as described above, when photopolymerization is performed in a reactor equipped with a movable conveyor belt, the form of the hydrogel polymer that is usually obtained may be a sheet-like hydrogel polymer having the width of the belt. At this time, the thickness of the polymer sheet varies depending on the concentration and injection speed of the monomer composition to be injected, but it is preferable to supply the monomer composition so that a sheet-shaped polymer having a thickness of about 0.5 to about 5 cm can be obtained. When the monomer composition is supplied to such an extent that the thickness of the sheet-like polymer is too thin, the production efficiency is low, which is undesirable, and when the thickness of the sheet-like polymer exceeds 5 cm, the polymerization reaction is uniform over the entire thickness due to the excessively thick thickness. may not happen

In addition, the moisture content of the hydrogel polymer obtained by the above method may be about 40 to about 80% by weight based on the total weight of the hydrogel polymer. Meanwhile, throughout the present specification, "moisture content" refers to a value obtained by subtracting the weight of the dry polymer from the weight of the hydrogel polymer as the content of moisture with respect to the total weight of the hydrogel polymer. Specifically, it is defined as a value calculated by measuring the weight loss due to moisture evaporation in the polymer during drying by raising the temperature of the polymer through infrared heating. At this time, the drying condition is a method of raising the temperature from room temperature to about 180 ° C and then maintaining it at 180 ° C. The total drying time is set to 20 minutes including 5 minutes of the temperature raising step, and the moisture content is measured.

Meanwhile, after preparing the hydrogel polymer, a coarse pulverization process of pulverizing the prepared water-containing gel polymer may be selectively performed prior to subsequent drying and pulverization processes.

The coarse grinding process is a process for increasing drying efficiency in the subsequent drying process and controlling the particle size of the super absorbent polymer powder to be produced. At this time, the grinder used is not limited in configuration, but specifically, a vertical cutter Vertical pulverizer, Turbo cutter, Turbo grinder, Rotary cutter mill, Cutter mill, Disc mill, Shred crusher ), a crusher, a meat chopper, and a disc cutter.

The coarse grinding process may be performed, for example, so that the particle diameter of the water-containing gel polymer is about 2 to about 10 mm. Grinding the water-containing gel polymer to a particle diameter of less than 2 mm is not technically easy due to the high water content of the water-containing gel polymer, and also may cause agglomeration of the pulverized particles. On the other hand, when the particle diameter is more than 10 mm, the effect of increasing the efficiency of the subsequent drying step is insignificant.

Next, step 2 is a step of forming a base resin containing a crosslinked polymer by drying, pulverizing, and classifying the hydrogel polymer prepared in step 1 above.

The drying method may be selected and used without limitation in configuration, as long as it is commonly used as a drying process for a hydrogel polymer. Specifically, the drying step may be performed by a method such as hot air supply, infrared ray irradiation, microwave irradiation, or ultraviolet ray irradiation.

Specifically, the drying may be performed at a temperature of about 120 to about 250 °C. When the drying temperature is less than 120 ° C, the drying time is too long and there is a concern that the physical properties of the finally formed superabsorbent polymer may be deteriorated, and when the drying temperature exceeds 250 ° C, only the polymer surface is excessively dried, resulting in a subsequent pulverization process There is a concern that fine powder may be generated in the water, and physical properties of the finally formed superabsorbent polymer may be deteriorated. Therefore, preferably, the drying may be performed at a temperature of 150 °C or higher, or 160 °C or higher, and 200 °C or lower, or 180 °C or lower.

Meanwhile, the drying time may be about 20 to about 90 minutes in consideration of process efficiency, but is not limited thereto.

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

A crushing process is performed after the drying process. The grinding process may be performed so that the particle diameter of the polymer powder, that is, the base resin, is about 150 to about 850 μm. The grinder used for grinding to such a particle size is specifically, a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill, or a jog mill. A jog mill or the like may be used, but the present invention is not limited to the above examples.

In addition, after the pulverization step as described above, a process of classifying the pulverized polymer powder according to the particle diameter may be further performed in order to manage the physical properties of the superabsorbent polymer to be finalized.

The base resin obtained as a result of the above process may have a fine powder form including a cross-linked polymer obtained by cross-linking an acrylic acid-based monomer and a polymerizable antibacterial monomer through a first cross-linking agent. Specifically, the superabsorbent polymer may have a fine powder form having a particle size of 150 to 850 μm or about 300 to about 600 μm.

Next, a step (step 3) of surface cross-linking by heat-treating the base resin prepared in step 2 in the presence of a second cross-linking agent is further included.

The surface crosslinking is a step of increasing the crosslinking density near the surface of the superabsorbent polymer in relation to the crosslinking density inside the particle. Generally, the second crosslinking agent is applied to the surface of the resin. Accordingly, this reaction takes place on the surface of the resin particles, which improves the crosslinkability on the surface of the particles without substantially affecting the inside of the particles. Therefore, the surface cross-linked superabsorbent polymer has a higher degree of cross-linking near the surface than inside.

The second crosslinking agent may be used in an amount of about 0.001 to about 5 parts by weight based on 100 parts by weight of the water-containing gel polymer. For example, the second crosslinking agent is 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, based on 100 parts by weight of the superabsorbent polymer. content can be used. By adjusting the content range of the second cross-linking agent within the above range, a superabsorbent polymer exhibiting excellent absorbent properties can be prepared.

In addition, there is no limitation on the configuration of the method of mixing the second crosslinking agent with the superabsorbent polymer. For example, a method of mixing the second crosslinking agent and the superabsorbent polymer in a reaction tank, spraying the second crosslinking agent to the superabsorbent polymer, continuously supplying the superabsorbent polymer and the second crosslinking agent to a continuously operated mixer and mixing them method, etc. can be used.

In addition to the second crosslinking agent, water and alcohol may be mixed together and added in the form of the surface crosslinking solution. When water and alcohol are added, there is an advantage in that the second crosslinking agent can be evenly dispersed in the superabsorbent polymer powder. At this time, the content of the added water and alcohol is about 100 parts by weight of the polymer for the purpose of inducing uniform dispersion of the second crosslinking agent, preventing agglomeration of the superabsorbent polymer powder, and optimizing the surface penetration depth of the crosslinking agent. It is preferably added in a proportion of 5 to about 12 parts by weight.

A surface cross-linking reaction may be achieved by heating the super absorbent polymer powder to which the second cross-linking agent is added at a temperature of about 80 to about 220 °C for about 15 to about 100 minutes. When the crosslinking reaction temperature is less than 80 °C, the surface crosslinking reaction may not sufficiently occur, and when it exceeds 220 °C, the surface crosslinking reaction may excessively proceed. In addition, if the crosslinking reaction time is too 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 surface of the particle becomes too high due to excessive surface crosslinking reaction, resulting in deterioration of physical properties. can More specifically, it can proceed by heating at a temperature of 120 ° C. or higher, or 140 ° C. or higher, 200 ° C. or lower, or 180 ° C. or lower, for 20 minutes or higher, or 40 minutes or higher, 70 minutes or lower, or 60 minutes or lower. .

The means for raising the temperature for the additional crosslinking reaction is not particularly limited. It can be heated by supplying a heat medium or directly supplying a heat source. At this time, as the type of heat medium that can be used, steam, hot air, heated fluids such as hot oil, etc. can be used, but the present invention is not limited thereto, and the temperature of the heat medium supplied depends on the means of the heat medium, the rate of temperature increase and the temperature rise. It can be selected appropriately in consideration of the target temperature. On the other hand, as the directly supplied heat source, heating through electricity or heating through gas may be mentioned, but the present invention is not limited to the above-described examples.

Meanwhile, a sanitary product including the above-described superabsorbent polymer is provided.

Hereinafter, in order to aid understanding of the present invention, it will be described in more detail. However, the following examples are merely illustrative of the present invention, and the contents of the present invention are not limited by the following examples.

[Example: Preparation of Super Absorbent Polymer]

Example 1

In a 3L glass container equipped with a stirrer, a nitrogen injector, and a thermometer, 100 parts by weight of acrylic acid, 0.35 parts by weight of polyethylene glycol diacrylate (PEGDA, Mn = 575) as a first crosslinking agent, and bis(2,4,6-trimethylbenzoyl as a photoinitiator) 0.008 parts by weight of )-phenylphosphine oxide, 0.12 parts by weight of sodium persulfate (SPS) as a thermal initiator, 123.5 parts by weight of a 31.5% pure sodium hydroxide solution, 54.9 parts by weight of water and 2-(tert-butylamino)ethyl A water-soluble unsaturated monomer aqueous solution was prepared by adding 5 parts by weight of methacrylate (2-(tert-butylamino)ethyl methacrylate, Sigma-Aldrich, product number: 444332) and continuously introducing nitrogen.

The aqueous solution of the water-soluble unsaturated monomer was transferred to a stainless steel container having a width of 250 mm, a length of 250 mm and a height of 30 mm, and ultraviolet rays were irradiated for ² minutes in a UV chamber at 80 ° C. A gel-like polymer was obtained.

After the obtained hydrogel polymer was pulverized to a size of 3 mm * 3 mm, the obtained gel resin was spread on a stainless wire gauze having a hole size of 600 μm to a thickness of about 30 mm and dried in a hot air oven at 120° C. for 11 hours. The dried polymer thus obtained was pulverized using a grinder and classified with a standard ASTM sieve to obtain a base resin having a particle size of 150 to 850 μm.

Meanwhile, for surface crosslinking (additional crosslinking) of the base resin, based on 100 parts by weight of the base resin, 5.4 parts by weight of water, 1.2 parts by weight of ethylene carbonate, 0.2 parts by weight of propylene glycol, and 0.2 parts by weight of a polycarboxylic acid surfactant And a surface crosslinking solution containing 0.2 parts by weight of aluminum sulfate was mixed and prepared. With respect to 100 parts by weight of the base resin, the surface crosslinking liquid was sprayed using a paddle type mixer at 1000 rpm. Thereafter, surface crosslinking was performed by heat treatment at a maximum temperature of 184° C. for 40 minutes to prepare the superabsorbent polymer of Example 1.

Example 2

In Example 1, except that 10 parts by weight of 2-(tert-butylamino)ethyl methacrylate was used and surface crosslinking was carried out at a maximum temperature of 178 ° C. for 30 minutes, the same method as in Example 1 was used to obtain high absorbency. Resin was prepared.

Comparative Example 1

A superabsorbent polymer was prepared in the same manner as in Example 1, except that 2-(tert-butylamino)ethyl methacrylate was not used in Example 1.

Comparative Example 2

2- (tert-butyl amino) ethyl methacrylate (18.5 g) and ethanol (30 mL) were added to a two-necked round bottom flask capable of maintaining a nitrogen environment, and the mixture was stirred for 10 minutes. Then, AIBN (Azobisisobutyronitrile (493 mg) was added and stirred at 80 ° C for 16 hours. After the temperature of the reaction mixture was lowered to room temperature, a small amount of ethanol was added to dilute the solution. The diluted solution was slowly added dropwise to distilled water to obtain The solid was filtered, washed with a small amount of distilled water and dried to obtain a 2-(tert-butyl amino)ethyl methacrylate polymer (Mw = 32856, Mn = 21055, Mp = 49340, PD = 1.6).

A superabsorbent polymer mixture was prepared by mixing 5 parts by weight of 2-(tert-butylamino)ethyl methacrylate polymer with 100 parts by weight of the superabsorbent polymer prepared in the same manner as in Comparative Example 1.

Comparative Example 3

2- (tert-butyl amino) ethyl methacrylate (18.5 g) and ethanol (30 mL) were added to a two-necked round bottom flask capable of maintaining a nitrogen environment, and the mixture was stirred for 10 minutes. Then, AIBN (Azobisisobutyronitrile (493 mg) was added and stirred at 80 ° C for 16 hours. After the temperature of the reaction mixture was lowered to room temperature, a small amount of ethanol was added to dilute the solution. The diluted solution was slowly added dropwise to distilled water to obtain The solid was filtered, washed with a small amount of distilled water and dried to obtain a 2-(tert-butyl amino)ethyl methacrylate polymer (Mw = 32856, Mn = 21055, Mp = 49340, PD = 1.6).

A superabsorbent polymer mixture was prepared by mixing 10 parts by weight of 2-(tert-butylamino)ethyl methacrylate polymer with 100 parts by weight of the superabsorbent polymer prepared in the same manner as in Comparative Example 1.

Mw, Mn, Mp, and PD of the 2-(tert-butyl amino)ethyl methacrylate polymer in Comparative Examples 2 and 3 were measured by the following methods. Molecular weight distribution (PD = Mw/Mn) was determined by measuring Mw and Mn using gel permeation chromatography (GPC). A Polymer Laboratories PLgel MIX-C/D 300 mm long column was used and evaluated using a Waters E2695, 2414 RI instrument. The evaluation temperature was 40 °C, N,N-dimethylformamide (DMF) was used as a solvent, and the flow rate was measured at a rate of 1 mL/min. Samples were prepared at a concentration of 5 mg/1 mL and then supplied in an amount of 100 μL. The values of Mw and Mn were derived using a calibration curve formed using polymethyl methacrylate (PMMA) standards. Nine kinds of polymethyl methacrylate standard molecular weights of 1,980 / 13,630 / 32,340 / 72,800 / 156,200 / 273,600 / 538,500 / 1,020,000 / 1,591,000 were used.

[Experimental example]

(1) Evaluation of antibacterial properties of polymeric antimicrobial monomers against E. coli

The antibacterial properties of the monomer 2-(tert-butylamino)ethyl methacrylate and the following monomer 2-(dimethylamino)ethyl methacrylate included in Examples were evaluated in the following manner.

The antibacterial properties against 2-(tert-butylamino)ethyl methacrylate were in Experimental Examples 1-1 to 1-3, and the antibacterial properties against 2-(dimethylamino)ethyl methacrylate were in Comparative Experimental Examples 1-1 to 1- 4.

After putting the monomer content into a 50 ml conical tube according to Table 1 below, 25 ml of Nutrient broth (Becton Dickinson Co.) solution inoculated with 3000±300 CFU/ml of E. coli (ATCC 25922) standard strain was injected. After culturing for 18 hours in a shaking incubator (Vision Science, VS-37SIF) at 35 °C, the culture solution was diluted to a concentration of 1/5 using 1X PBS (Gibco). The absorbance of the diluted solution was measured at a wavelength of 600 nm using a UV-Vis Spectrophotometer. At this time, the degree of culture of the bacteria was confirmed by comparing the absorbance of the sample in which the monomer was added to the absorbance measured by culturing the Nutrient broth solution inoculated with the bacteria without adding the monomer. The bacterial growth inhibition rate was calculated according to Equation 1 below, and the results are shown in Table 1 below.

[Equation 1]

Bacterial growth inhibition rate (%) = [(OD _Reference - OD _Sample ) / OD _Reference ] * 100

In the above formula, OD _Reference is the absorbance in the culture medium of Comparative Experimental Example 1-1 not containing the bacteriostatic substance, and OD _sample is the absorbance in the culture medium containing the bacteriostatic substance.

monomer type monomer content
(g) Optical
density Bacterial growth inhibition rate
(%) Experimental Example 1-1 2-(tert-butylamino)ethyl methacrylate 0.03 0.185 5.61 Experimental Example 1-2 2-(tert-butylamino)ethyl methacrylate 0.05 0.070 64.29 Experimental Example 1-3 2-(tert-butylamino)ethyl methacrylate 0.07 0.009 95.41 Comparative Experimental Example 1-1 2-(tert-butylamino)ethyl methacrylate 0 0.196 0 Comparative Experimental Example 1-2 2-(dimethylamino)ethyl methacrylate 0.03 0.196 0.00 Comparative Experimental Example 1-3 2-(dimethylamino)ethyl methacrylate 0.05 0.189 3.67 Comparative Experimental Example 1-4 2-(dimethylamino)ethyl methacrylate 0.07 0.149 23.98

According to Table 1, when the polymerizable antibacterial monomer of the present invention is included, the terminal substituent is different from the tertiary amine group in Comparative Experimental Example, which is superior to the bacteriostatic monomer containing the same amount of 2-(dimethylamino)ethyl methacrylate. It was confirmed that the reduction rate was indicated.

(2) Evaluation of antibacterial properties of polymeric antimicrobial monomers against Proteus mirabilis (P. mirabilis)

In order to investigate the antibacterial properties of the monomer 2-(tert-butylamino)ethyl methacrylate and the monomer 2-(dimethylamino)ethyl methacrylate contained in the Examples against Proteus mirabilis, the antibacterial properties against E. coli In the evaluation of properties, the same method was used except that the Nutrient Broth solution inoculated with 3000±300 CFU/ml of Proteus mirabilis (P. mirabilis, ATCC 29906) standard strain instead of E. coli (ATCC 25922) was used. The bacterial growth inhibition rate (%) of Proteus mirabilis was calculated, and the results are shown in Table 2 below.

At this time, in the calculation of the bacteriostatic reduction rate using Equation 1, C _Reference is the number of CFU of bacteria after culturing the monomer of Comparative Experimental Example 2-1 that does not contain a bacteriostatic substance.

monomer type monomer content
(g) Optical
density Bacterial growth inhibition rate
(%) Experimental Example 2-1 2-(tert-butylamino)ethyl methacrylate 0.03 0.144 19.10 Experimental Example 2-2 2-(tert-butylamino)ethyl methacrylate 0.05 0.100 43.82 Experimental Example 2-3 2-(tert-butylamino)ethyl methacrylate 0.07 0.009 94.94 Comparative Experimental Example 2-1 2-(tert-butylamino)ethyl methacrylate 0 0.178 0 Comparative Experimental Example 2-2 2-(dimethylamino)ethyl methacrylate 0.03 0.172 3.37 Comparative Experimental Example 2-3 2-(dimethylamino)ethyl methacrylate 0.05 0.142 20.22 Comparative Experimental Example 2-4 2-(dimethylamino)ethyl methacrylate 0.07 0.057 67.98

According to Table 2, when the polymerizable antibacterial monomer of the present invention is included, the substituent at the terminal is different from the tertiary amine group, and the bacteriostatic monomer 2-(dimethylamino)ethyl methacrylate of the Comparative Example is superior to that containing the same content. It was confirmed that the reduction rate was indicated.

(3) Evaluation of water absorption properties of superabsorbent polymer

For the superabsorbent polymers of Examples and Comparative Examples, centrifuge retention capacity (CRC) was measured by the following method and shown in Table 3.

According to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 241.3, the centrifugal water retention capacity of each of the superabsorbent polymer and the base resin of Examples and Comparative Examples was measured according to the absorption capacity under no load.

Specifically, the superabsorbent polymer W ₀ (g) (about 0.2 g) was uniformly placed in a bag made of non-woven fabric, sealed, and immersed in physiological saline (0.9 wt % sodium chloride aqueous solution) at room temperature. After 30 minutes, water was drained from the bag for 3 minutes under the condition of 250G using a centrifuge, and the weight of the bag W ₂ (g) was measured. Moreover, after carrying out the same operation without using resin, the weight _W1 (g) at that time was measured. Using each obtained mass, CRC (g/g) was calculated according to the following equation.

[Equation 3]

CRC (g/g) = {[W ₂ (g) - W ₁ (g)]/W ₀ (g)} - 1

In Equation 3 above,

W ₀ (g) is the initial weight (g) of the superabsorbent polymer,

W ₁ (g) is the weight of the bag measured after immersing and absorbing the bag in physiological saline for 30 minutes without using a superabsorbent polymer, and then dehydrating the bag at 250 G for 3 minutes using a centrifuge,

W ₂ (g) is the weight of the bag including the superabsorbent polymer after soaking the superabsorbent polymer in physiological saline at room temperature for 30 minutes and absorbing it, dehydrating the bag at 250 G for 3 minutes using a centrifuge.

(4) Evaluation of antibacterial properties of superabsorbent polymer against E. coli

Artificial urine inoculated with 3000±300 CFU/ml of E. coli (ATCC 25922) standard strain, which is a test bacterium, after putting 2 g of the superabsorbent polymer prepared in the above Examples and Comparative Examples in a 250 ml cell culture flask. 50 ml was injected. Thereafter, the superabsorbent polymer was mixed for about 1 minute to sufficiently absorb the artificial urine solution, and the polymer sufficiently absorbed in the solution showed a gel form, which was maintained at 35 ° C. cultured for a while. 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 spread on an Agar medium plate. Afterwards, serial dilution was performed to enable colony counting, and 0.9 wt% NaCl solution was used in this process. For the bacteriostatic performance, the bacteriostatic reduction rate (%) of E. coli (E. coli, ATCC 25922) was calculated according to Equation 1 below after calculating the microbial concentration (Co, CFU / ml) of the initial concentration in consideration of the dilution concentration, The results are shown in Table 3 below.

[Equation 2]

Bacteriostatic reduction rate (%) = (1 - C _sample / C _Reference ) * 100

At this time, in the calculation of the bacteriostatic reduction rate using Equation 1, C _sample is the CFU number of bacteria after culturing the super absorbent polymer containing the bacteriostatic material, and C _Reference is after culturing the super absorbent polymer of Comparative Example 1 without the bacteriostatic material is the number of CFUs of bacteria.

(5) Evaluation of antibacterial properties of superabsorbent polymer against Proteus mirabilis (P. mirabilis)

In order to examine the antibacterial properties of the superabsorbent polymers prepared in Examples and Comparative Examples against Proteus mirabilis (P. mirabilis), instead of E. coli (ATCC 25922) standard strain, Proteus mirabilis (P. mirabilis), the bacteriostatic reduction rate (%) of Proteus mirabilis was calculated in the same manner as in '(4) Evaluation of antibacterial properties of superabsorbent polymer against E. coli' above, except for using It is shown in Table 3 below.

(6) Evaluation of ammonia deodorization

For the superabsorbent polymers of Examples and Comparative Examples, deodorization was evaluated in the following manner.

Specifically, artificial urine inoculated with Proteus Mirabilis (ATCC 29906) at 10,000 CFU/ml was treated with the superabsorbent polymer prepared in Examples and Comparative Examples at a concentration of 0.04 g/ml per 1 ml of solvent. ml, respectively, and incubated for 12 hours at 35 ° C. in an incubator (JEIO TECH). After connecting the ammonia detection tube (Gas Tech Co., ammonia 3M) and a suitable pump (Gas Tech Co., GV-100) using an injection needle to the vessel in which the culture was completed, 50 ml was extracted. The color of the detector tube was changed by ammonia, and the scale was checked and compared. The composition of the artificial urine used at this time was J Wound Ostomy Continence Nurs . 2017; 44 (1) 78-83. The results are shown in Table 3 below.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 CRC of base resin (g/g) 43.7 40.4 44.6 43.7 43.7 CRC of final superabsorbent polymer (g/g) 35.6 37.4 36.7 35.6 35.6 Surface crosslinking time (min) 40 30 40 40 40 Surface crosslinking temperature (℃) 184 178 184 184 184 Bacteriostatic reduction of E. coli (%) 47.05 95.49 - 0 4.05 Bacteriostatic reduction rate of Proteus Mirabilis (%) 87.85 99.99 - 0 9.40 Ammonia (ppm) < 10 < 10 > 500 > 500 > 500

As a result of Table 3, the superabsorbent polymers of Examples 1 and 2 and Comparative Example 1 had CRCs equivalent to each other by adjusting the surface crosslinking time and temperature, but had a high bacteriostatic reduction rate against E. coli and Proteus mirabilis, resulting in antimicrobial activity. characteristics could be confirmed. Comparative Examples 2 and 3 used the superabsorbent polymer of Example 1 and had the same absorbent properties as Example 1, but it was confirmed that antibacterial properties against E. coli and Proteus mirabilis were significantly inferior only by simple mixing.

In addition, Proteus mirabilis is a microorganism having an enzyme such as Urease and decomposes Urea contained in artificial urine in the form of ammonia. As Proteus mirabilis proliferates, the amount of ammonia produced increases and the odor of urine greatly increases. . As shown in Table 3, in the examples, it was confirmed that the deodorizing effect by the antibacterial action was excellent, as the amount of ammonia generation was greatly reduced compared to the comparative example.

Claims (12)

A base resin comprising an acrylic acid-based monomer containing an acidic group and at least a portion of the acidic group neutralized, a polymerizable antibacterial monomer represented by Formula 1 below, and a crosslinked polymer in which a first crosslinking agent is polymerized,
At least a portion of the base resin is surface-treated by the second crosslinking agent,
Super Absorbent Resin:
[Formula 1]

In Formula 1,
R ₁ to R ₃ are each independently hydrogen or methyl;
R ₄ is hydrogen or substituted or unsubstituted alkyl having 1 to 20 carbon atoms;
L ₁ is a substituted or unsubstituted alkylene having 1 to 10 carbon atoms.
According to claim 1,
R ₁ and R ₂ are each hydrogen;
R ₃ is methyl;
super absorbent polymer.
According to claim 1,
R ₄ is tertbutyl;
super absorbent polymer.
According to claim 1,
L ₁ is ethylene;
super absorbent polymer
According to claim 1,
The polymerizable antibacterial monomer is a compound represented by the following formula 1-1,
super absorbent polymer.
[Formula 1-1]

.
According to claim 1,
The polymerizable antibacterial monomer is used in an amount of 5 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the acrylic acid monomer.
super absorbent polymer.
According to claim 1,
The superabsorbent polymer exhibits antibacterial activity against Gram-negative bacteria.
super absorbent polymer.
According to claim 7,
The gram-negative bacteria are Escherichia coli or Proteus mirabilis,
super absorbent polymer.
According to claim 1,
The superabsorbent polymer has a centrifugal retention capacity (CRC) of 20 g/g or more and 45 g/g or less for 30 minutes in physiological saline (0.9 wt% aqueous sodium chloride solution) measured according to WSP 241.3 of the EDANA method.
super absorbent polymer.
Forming a water-containing gel polymer by crosslinking polymerization of an acrylic acid-based monomer containing an acidic group and at least partially neutralizing the acidic group and a polymerizable antibacterial monomer represented by Formula 1 in the presence of a first crosslinking agent and a polymerization initiator;
drying, pulverizing, and classifying the water-containing gel polymer to form a base resin including a crosslinked polymer; and
In the presence of a second cross-linking agent, heat-treating the base resin to surface cross-link,
Manufacturing method of superabsorbent polymer:
[Formula 1]

In Formula 1,
R ₁ to R ₃ are each independently hydrogen or methyl;
R ₄ is hydrogen or substituted or unsubstituted alkyl having 1 to 20 carbon atoms;
L ₁ is a substituted or unsubstituted alkylene having 1 to 10 carbon atoms.
According to claim 10,
The polymerizable antibacterial monomer is used in an amount of 5 parts by weight or more and 20 parts by weight or less based on 100 parts by weight of the acrylic acid monomer.
A method for producing a superabsorbent polymer.
A sanitary product comprising the superabsorbent polymer according to any one of claims 1 to 9.