KR20200073751A - Method for preparing antibacterial super absorbent polymer - Google Patents

Abstract

The present invention relates to a method for preparing an antibacterial super absorbent resin capable of providing an enhanced antibacterial effect without any decline in basic absorption performance, preventing odor-causing problems caused by the growth of bacteria, significantly reducing dust generated during a preparation process, and improving anti-caking efficiency by inputting an antibacterial agent into surface crosslinking liquid for forming a surface crosslinking layer of a super absorbent resin, so as to form the surface crosslinking layer, and further inputting citric acid into the surface crosslinking liquid when forming the surface crosslinking layer, or forming the surface crosslinking layer and further inputting citric acid therein, so as to carry out dry mixing.

Description

Manufacturing method of antimicrobial superabsorbent polymer {METHOD FOR PREPARING ANTIBACTERIAL SUPER ABSORBENT POLYMER}

The present invention relates to a method for producing an antimicrobial superabsorbent polymer capable of satisfying both stability and fairness by exhibiting improved antibacterial and deodorizing properties with excellent absorption performance and liquid permeability, and significantly reducing dust generated during the process. will be.

Super Absorbent Polymer (SAP) is a synthetic polymer material that has the ability to absorb about 500 to 1,000 times the weight of its own weight with hydrophilic (COOH, COO ^- Na ⁺ ) functional groups. Each has a different name, such as SAM (Super Absorbency Material) and AGM (Absorbent Gel Material). The superabsorbent polymer as described above began to be put into practical use as a sanitary tool, and now, in addition to hygiene products such as paper diapers for children, soil repair agents for horticulture, civil engineering, construction index materials, nursery sheets, freshness preserving agents in the food distribution field, and It is widely used as a material for poultice.

In most cases, these superabsorbent polymers are widely used in the field of sanitary materials such as diapers and sanitary napkins, and the odor as well as the feeling of wearing after absorbing moisture is an important problem in the superabsorbent polymer for diapers. In particular, secondary odors caused by bacterial growth in diapers for adults cause problems that cause discomfort to consumers. Therefore, it is necessary to develop a deodorant/antibacterial superabsorbent resin to suppress the odor caused by substances produced by metabolic activity of microorganisms present in urine and feces.

To solve this problem, attempts have been made to introduce various deodorizing or antibacterial functional ingredients into the superabsorbent polymer composition.

However, in the existing attempts to introduce such various deodorant/antibacterial functional components, even if the deodorant/antibacterial properties of the super absorbent polymer are exhibited, the processability is reduced due to a large amount of dust during the process, and the problem of reduced workability due to dust have. In addition, in the case of the conventional method, the stability of the super absorbent polymer is lowered, and the functional component itself is too expensive, and thus, the unit cost of the super absorbent polymer composition is too high.

Accordingly, development of a superabsorbent polymer that exhibits improved antibacterial and deodorant properties without sacrificing the basic absorbent performance of the superabsorbent polymer and satisfies both stability and fairness as well as excellent economic efficiency has been continuously requested.

Thus, the present invention can show an improved antibacterial effect while maintaining excellent absorption performance and liquid permeability, thereby preventing odor-causing problems caused by the growth of bacterial bacteria, and dramatically reducing dust generated during the manufacturing process, An object of the present invention is to provide a method for producing an antimicrobial superabsorbent polymer, which can improve anticaking efficiency.

According to an embodiment of the present invention, in the presence of an internal crosslinking agent, crosslinking polymerization of a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized to form a hydrogel polymer comprising a crosslinked polymer;

Drying, grinding and classifying the hydrogel polymer to form a base resin powder; And

A method for producing an antimicrobial superabsorbent polymer comprising mixing and reacting a surface crosslinking liquid containing a non-epoxy watch surface crosslinking agent, an antibacterial agent, and water with the base resin powder to form a surface crosslinking layer,

In the manufacturing method, when the surface crosslinking layer is formed, citric acid is additionally added to the surface crosslinking solution to form a surface crosslinking layer; Or after the formation of the surface cross-linking layer further comprises the step of dry mixing with the superabsorbent polymer is formed by adding a citric acid to the surface cross-linking layer,

The citric acid is added in an amount of 0.1 to 3 parts by weight based on the total weight of the base resin powder,

Preparation of an antimicrobial superabsorbent polymer having a gel permeability (GPUP) under pressure calculated according to Equation 1 below is 22 to 24 ⅹ 10E ^-13 m ² , and an anticaking efficiency calculated according to Equation 5 below is 90% or more. Provides a method.

[Equation 1]

GPUP (ⅹ10E ^-13 m ² )=(Ｋⅹηⅹ10/10000) ⅹ1000000

[Equation 5]

Anti-caking efficiency (%) = [S1/(S2-W1) + S1] ⅹ 100

In Equations 1 and 5, K, η, S1, S2 and W1 are as defined below.

Hereinafter, a super absorbent polymer according to a specific embodiment of the present invention and a method of manufacturing the same will be described in more detail. However, this is provided as an example of the invention, and the scope of rights of the invention is not limited by this, and it is apparent to those skilled in the art that various modifications to the embodiments are possible within the scope of the invention.

Additionally, unless otherwise stated throughout this specification, "comprising" or "containing" refers to the inclusion of any component (or component) without particular limitation, and the addition of another component (or component). It cannot be interpreted as being excluded.

Method of manufacturing an antimicrobial superabsorbent polymer according to an embodiment of the invention,

Crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized in the presence of an internal crosslinking agent to form a hydrogel polymer comprising a crosslinked polymer;

Drying, grinding and classifying the hydrogel polymer to form a base resin powder; And

And mixing and reacting a surface crosslinking liquid containing a non-epoxy watch surface crosslinking agent, an antibacterial agent, and water with the base resin powder to form a surface crosslinking layer,

In the manufacturing method, when the surface crosslinking layer is formed, citric acid is additionally added to the surface crosslinking solution to form a surface crosslinking layer; Or after the formation of the surface cross-linking layer further comprises the step of dry mixing with the superabsorbent polymer is formed by adding a citric acid to the surface cross-linking layer,

The citric acid is added in an amount of 0.1 to 3 parts by weight based on the total weight of the base resin powder.

Conventional antimicrobial superabsorbent polymer was prepared by a method of dry mixing the antimicrobial agent after the production of the superabsorbent polymer. However, in this case, there was a problem that the amount of dust generated increased and the manufacturing efficiency of the super absorbent polymer decreased. Accordingly, it was required to add an additive to suppress dust generation and a mixing process therefor.

On the other hand, in the present invention, by adding an antimicrobial agent to the surface crosslinking liquid for forming a surface crosslinking layer of the super absorbent polymer and adding it in a wet manner, dust generation is reduced, anti-caking efficiency is increased, and conventional dry type In contrast to the antimicrobial agent present only on the surface of the superabsorbent polymer upon mixing, the antibacterial agent is uniformly distributed on the surface and inside of the superabsorbent polymer to be produced, thereby exhibiting a markedly improved excellent bacterial growth inhibitory effect. In addition, upon formation of the surface crosslinking layer, by adding citric acid, which has been verified for human safety, into the surface crosslinking solution, or by adding citric acid after the formation of the surface crosslinking layer to dry mixing, the pH is lowered to further inhibit the growth of bacteria. Enhancement and neutralization of ammonia caused by bacterial growth can show deodorant effect. As a result, it is possible to effectively suppress the bacterial proliferation and odor-induced problems caused by bacteria in diapers, especially in adult diapers.

Hereinafter, a method of manufacturing an antibacterial superabsorbent polymer according to an embodiment of the present invention will be described in detail for each step.

First, step 1 is a step of cross-linking polymerization of a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized in the presence of an internal crosslinking agent to form a hydrogel polymer comprising a crosslinked polymer.

The water-soluble ethylenically unsaturated monomers are acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2-(meth)acryloyl Propanesulfonic acid, or anionic monomers of 2-(meth)acrylamide-2-methyl propane sulfonic acid and salts thereof; (Meth)acrylamide, N-substituted (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate or polyethylene glycol ( Nonionic hydrophilic monomers of meth)acrylate; And an amino group-containing unsaturated monomer of (N,N)-dimethylaminoethyl (meth)acrylate or (N,N)-dimethylaminopropyl (meth)acrylamide and a quaternized product thereof. It can contain. Among these, an alkali metal salt such as acrylic acid or a salt thereof, for example, acrylic acid in which at least a part of acrylic acid is neutralized and/or a sodium salt thereof can be used, and the use of such monomers leads to the preparation of a super absorbent polymer having better physical properties Becomes possible. When using the acrylic acid and its alkali metal salt as a monomer, it can be used by neutralizing at least a part of acrylic acid with a basic compound such as caustic soda (NaOH).

In addition, as an internal crosslinking agent for crosslinking polymerization of these monomers, bis(meth)acrylamide having 8 to 12 carbon atoms, poly(meth)acrylate of a polyol having 2 to 10 carbon atoms and poly(meth) of a polyol having 2 to 10 carbon atoms One or more selected from the group consisting of allyl ethers can be used. More specifically, the internal crosslinking agent is one selected from the group consisting of polyethylene glycol di(meth)acrylate, polypropyleneoxy di(meth)acrylate, glycerin diacrylate, glycerin triacrylate, and trimethyrol triacrylate. The poly(meth)acrylate of the above polyol can be used suitably. Among these, by using an internal crosslinking agent such as the polyethylene glycol di(meth)acrylate, an internal crosslinking structure is optimized and a base resin powder having a high gel strength, etc. can be obtained. An absorbent resin can be obtained more appropriately.

In addition, 0.005 to 0.1 mol, or 0.005 to 0.1 mol, or 0.005 to 0.05 mol (or more than 0.3 parts by weight compared to 100 parts by weight of acrylic acid), or 0.3 to 0.6 parts by weight). Depending on the content range of the internal crosslinking agent, a base resin powder having a high gel strength before surface crosslinking can be appropriately obtained, and a superabsorbent polymer having excellent physical properties can be obtained through the method of one embodiment.

In addition, after crosslinking and polymerizing the monomer using the internal crosslinking agent, a base resin powder may be obtained through processes such as drying, pulverization, and classification. Through these pulverization and classification processes, the base resin powder and It is appropriate that the resulting superabsorbent polymer is prepared and provided to have a particle diameter of 150 to 850 μm. More specifically, at least 95% by weight or more of the base resin powder and the superabsorbent polymer obtained therefrom has a particle diameter of 150 to 850㎛, and a fine powder having a particle diameter of less than 150㎛ is less than 3% by weight, or less than 1.5% by weight Can be as

In addition, the concentration of the water-soluble ethylenically unsaturated monomer may be 20 to 60% by weight, or 40 to 50% by weight relative to the total monomer composition including each raw material and solvent described above, polymerization time and reaction conditions, etc. It can be adjusted to an appropriate concentration.

In addition, the polymerization initiator is not particularly limited as long as it is generally used for the production of super absorbent polymers. Specifically, the polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator according to UV irradiation depending on the polymerization method. However, even with the photopolymerization method, since a certain amount of heat is generated by irradiation with ultraviolet rays or the like and a certain amount of heat is generated as the polymerization reaction that is an exothermic reaction proceeds, a thermal polymerization initiator may be additionally included.

The photopolymerization initiator may be included in an amount of 0.01 to 1.0 parts by weight based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. If the content of the photopolymerization initiator is too low, the polymerization rate may be slow, and if the concentration of the photopolymerization initiator is too high, the molecular weight of the super absorbent polymer may be small and the physical properties may be uneven.

The thermal polymerization initiator may be included in 0.001 to 0.5 parts by weight based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. When the content of the thermal polymerization initiator is too low, additional thermal polymerization hardly occurs, so the effect of adding the thermal polymerization initiator may be negligible. If the concentration of the thermal polymerization initiator is too high, the molecular weight of the super absorbent polymer may be small and physical properties may be uneven. have.

In addition, the monomer composition may further include additives such as a thickener, a plasticizer, a preservative stabilizer, and an antioxidant, if necessary.

Raw materials such as the above-described water-soluble ethylenically unsaturated monomer, photopolymerization initiator, thermal polymerization initiator, internal crosslinking agent and additives may be prepared in the form of a solution of a monomer composition dissolved in a solvent.

The solvent that can be used at this time can be used without limitation of its configuration as long as it can dissolve the aforementioned components, 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 It can be used in combination of one or more selected from ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate and N,N-dimethylacetamide.

The solvent may be included in the remaining amount excluding the above-mentioned components with respect to the total content of the monomer composition.

On the other hand, if the method of forming a hydrogel polymer by thermal polymerization or photopolymerization of such a monomer composition is also a commonly used polymerization method, there is no particular limitation on the configuration.

Specifically, the polymerization method is largely divided into thermal polymerization and photopolymerization according to the polymerization energy source, and in general, when performing thermal polymerization, it can be carried out in a reactor having a stirring axis such as a kneader, and when performing photopolymerization, it is movable Although it may be carried out in a reactor equipped with a conveyor belt, the polymerization method described above is an example, and the present invention is not limited to the polymerization method described above.

Next, step 2 is a step of drying, grinding, and classifying the hydrogel polymer prepared in step 1 to form a base resin powder.

The drying, grinding and/or classification process for forming the base resin powder may be performed according to a conventional method.

Next, step 3 is a step of forming a surface crosslinking layer by mixing and reacting a surface crosslinking solution containing a non-epoxy watch surface crosslinking agent, an antibacterial agent, and water with the base resin powder.

The surface crosslinking solution may be prepared by mixing and dissolving a non-epoxy watch surface crosslinking agent, an antibacterial agent, and water according to a conventional method. Specifically, 0.01 to 5 parts by weight of a non-epoxy watch surface crosslinking agent, 0.1 to 1.5 parts by weight of an antibacterial agent, and 0.5 to 10 parts by weight of water are mixed with respect to 100 parts by weight of the base resin powder prepared in step 2 to prepare a surface crosslinking solution. .

The antimicrobial agent may act as an antibacterial agent that inhibits the growth rate of various bacteria, in particular, the proliferation of Proteus mirabilis bacterial bacteria that cause odor. The antibacterial agent can be used without particular limitation, as long as it is usually used in the production of an antibacterial superabsorbent polymer. However, in the case of a biocide-based antimicrobial agent that breaks through the cell wall of bacteria and kills bacteria, it can also kill beneficial bacteria in addition to harmful bacteria. In the manufacturing method according to an embodiment of the present invention, it is necessary for the metabolism of bacterial bacteria such as Proteus mirabilis. Ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) or a salt thereof, which inhibits the proliferation by inhibiting the metabolism of bacterial bacteria by chelating the polyvalent metals, can be used.

Specific examples include EDTA, EDTA 2Na (ethylenediamine-N,N,N',N'tetraacetic acid, disodium salt), dihydrate EDTA 3Na (ethylenediamine-N,N,N',N'-tetraacetic acid, 3 Sodium salt, trihydrate), EDTA 4Na (ethylenediamine-N,N,N',N'-tetraacetic acid, tetrasodium salt), tetrahydrate EDTA 2K ethylenediamine-N,N,N',N'-tetraacetic acid , Dipotassium salt), dihydrate EDTA 2Li (ethylenediamine N,N,N',N'-tetraacetic acid, iridium salt), monohydrate EDTA (2NH4 ethylenediamine-N,N,N',N' tetraacetic acid , Diammonium salt), EDTA 3K (ethylenediamine-N,N,N',N'-tetraacetic acid, tripotassium salt), dihydrate Ba(II)-EDTA (ethylenediamine-N,N,N',N '-Tetraacetic acid, barium chelate), and the like, and any one or a mixture of two or more of them may be used.

When the antimicrobial agent is located not only on the surface of the antimicrobial superabsorbent polymer that is finally manufactured, but also on the inside, it can exhibit a better and uniform antibacterial effect. For this, it is required to have excellent solubility in water and completely dissolve in a water solution. Accordingly, among the above-described antibacterial agents, EDTA or alkali metal salts having excellent solubility in water and having safety as an antibacterial agent may be used, and more specifically, alkali metal salts of EDTA or EDTA-4Na may be used. The EDTA-4Na exhibits a particularly excellent deodorizing effect on the removal of the most critical NH ₃ among various odors of urine.

When preparing a superabsorbent polymer composition having antimicrobial properties, the higher the content of the antimicrobial agent, the better, but if other materials other than the superabsorbent polymer are added, physical properties may be deteriorated. In addition, in the manufacturing method according to an embodiment of the present invention, the antimicrobial agent is added through a wet method, but the antimicrobial agent added for antimicrobial activity may be a direct factor for causing fines. Accordingly, it is preferable to optimize the content of the antibacterial agent in consideration of the content of citric acid and water used. Specifically, the antimicrobial agent may be included in the aqueous solution in an amount corresponding to 0.1 to 1.5 parts by weight based on 100 parts by weight of the super absorbent polymer. If the content of the antibacterial agent is less than 0.1 parts by weight, it is difficult to obtain a sufficient antibacterial effect, and when it exceeds 1.5 parts by weight, there is a concern that the physical properties of the antibacterial superabsorbent polymer may decrease or the amount of dust generated may increase. More specifically, it is 0.2 parts by weight or more, or 0.25 parts by weight or more, and 1.2 parts by weight or less, or 1 part by weight or less based on 100 parts by weight of the super absorbent polymer.

In addition, a non-epoxy clock compound may be used as the surface crosslinking agent. In the case of the conventional epoxy-based surface crosslinking agent, there was a problem harmful to the human body, such as generating carcinogens by remaining in the diaper. On the other hand, in the present invention, the above-mentioned problems are solved by using a non-epoxy watch compound, and at the same time, human body safety and surface crosslinking properties of the superabsorbent polymer to be produced can be further improved.

Specifically, the non-epoxy clock crosslinking agent is a polyhydric alcohol compound having 3 to 20 carbon atoms such as 1,3-propanediol, polyamine compound, oxazoline-based compound, mono-, di- and poly-oxazolidinone compound, cyclic urea compound , One or more selected from the group consisting of a polyvalent metal salt and an alkylene carbonate compound having 2 to 5 carbon atoms.

The non-epoxy watch surface crosslinking agent may be used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the base resin powder. When the content of the surface crosslinking agent is less than 0.01 part by weight, it is difficult to form a sufficient surface crosslinking layer, and when it exceeds 5 parts by weight, the surface crosslinking layer is formed too thick, and there is a concern that the physical properties of the super absorbent polymer may be deteriorated. More specifically, the surface cross-linking agent is 0.1 part by weight or more, or 0.3 part by weight or more, and 1 part by weight or less, or 0.5 part by weight or less based on 100 parts by weight of the base resin powder.

Moreover, the said surface crosslinking liquid contains water as a medium.

The water may be included in an amount of 0.5 to 10 parts by weight based on 100 parts by weight of the base resin. If the water content is less than 0.5 parts by weight, the penetration of the antimicrobial agent into the superabsorbent polymer is not easy, and if it exceeds 10 parts by weight, there is a fear that the water retention capacity is reduced due to the CRC drop. More specifically, it is 0.7 parts by weight or more, or 3 parts by weight or more, and 7 parts by weight or less, or 6 parts by weight or less based on 100 parts by weight of the super absorbent polymer.

The surface cross-linking solution is prepared by dissolving the above-described non-epoxy watch surface modifier and antibacterial agent in water. At this time, for homogeneous mixing and complete dissolution of the surface modifier and antibacterial agent, a process such as agitation may be selectively performed.

The surface crosslinking step using the above-described surface crosslinking solution may be performed by heating for 5 minutes to 80 minutes at a temperature of 170 to 200°C. More specifically, heat treatment is performed for 5 minutes to 80 minutes, or 10 minutes to 70 minutes, or 20 minutes to 65 minutes at a reaction temperature of 175°C to 190°C for the base resin powder to which the surface crosslinking solution is added. It can proceed by the method of advancing the surface crosslinking reaction.

The heating means for the surface crosslinking reaction is not particularly limited. The heating medium may be supplied or a heat source may be directly supplied to heat. At this time, as the kind of heat medium that can be used, heated fluid such as steam, hot air, and hot oil may be used, but the present invention is not limited thereto, and the temperature of the supplied heat medium means the means of the heat medium, the rate of temperature increase and the target temperature of temperature increase. It can be appropriately selected in consideration. On the other hand, the heat source supplied directly may include a heating method through electricity and a gas, but is not limited to the above-described example.

Method for producing an antimicrobial superabsorbent polymer according to an embodiment of the present invention, when adding the citric acid in the surface crosslinking liquid when the surface crosslinking layer is formed, or after the surface crosslinking layer forming step, the superabsorbent surface crosslinked layer is formed The method further comprises dry mixing the resin with citric acid.

Despite the bacteriostatic growth inhibitory action of the antimicrobial agent, some bacteria may remain, and in this case, ammonia may be generated due to the remaining bacteria, thereby causing odor. These odors can be removed by the citric acid. As a result, the antimicrobial superabsorbent polymer prepared according to one embodiment of the present invention may exhibit better deodorizing and antibacterial properties by synergistic effect of two components, an antibacterial agent and citric acid.

The citric acid is distributed on the inside and the surface of the antimicrobial superabsorbent polymer particles, and generates an acid site. In addition to physically adsorbing bacteria and malodorous components at such an acidic point, the hydrogen cation (H ⁺ ) of the acidic point can be combined with the malodorous component to form an ammonium salt, thereby effectively removing malodorous components. In addition, the citric acid may exhibit an anti-caking performance that does not induce caking when mixed with a superabsorbent polymer by controlling the particle size.

The citric acid has a higher human safety, more COOH, and can show a better effect on deodorizing ammonia, and can show a better effect in anti-caking compared to other organic acids such as oxalic acid, fumaric acid, or maleic acid. . In addition, citric acid may exhibit excellent effects in deodorizing ammonia odor caused by bacterial growth when used in combination with EDTA or a salt thereof, especially EDTA-4Na, among antibacterial agents.

However, the citric acid has a high solubility, and the amount of the superabsorbent polymer is reduced by the amount to be added, so there is a limit to the amount of input. Specifically, the citric acid may be added in 0.1 to 3 parts by weight based on 100 parts by weight of the base resin powder. When the amount of citric acid is added is less than 0.1 part by weight, it is difficult to obtain a sufficient effect according to the addition of citric acid, and when it exceeds 3 parts by weight, there is a concern that the physical properties of the super absorbent polymer may be deteriorated.

More specifically, when the citric acid is additionally added to the surface crosslinking liquid, the citric acid is added in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the base resin powder when the surface crosslinking layer is formed under conditions that satisfy the above content conditions. Can be put in. When the input amount of citric acid is less than 0.5 parts by weight, there is a fear that the improvement effect due to the addition of citric acid is insufficient, and when it exceeds 2 parts by weight, there is a fear that it is not dissolved due to the low solubility of citric acid. More specifically, it may be included in 0.5 to 1 part by weight based on 100 parts by weight of the base resin powder.

In addition, when the citric acid is added through dry mixing with the superabsorbent polymer on which the surface crosslinked layer is formed, after the step of forming the surface crosslinked layer, 0.5 to 3 parts by weight based on 100 parts by weight of the superabsorbent polymer on which the surface crosslinked layer is formed may be added. have. When the input amount of citric acid is less than 0.5 parts by weight, the improvement effect according to the input of citric acid is insignificant, and when it exceeds 3 parts by weight, the physical properties of the super absorbent polymer may be deteriorated. More specifically, it may be included in 1 to 3 parts by weight based on 100 parts by weight of the super absorbent polymer having a surface crosslinked layer.

In addition, when the citric acid is introduced through dry mixing with a super absorbent polymer having a surface crosslinked layer, the dry mixing may be performed using a conventional mixing device, for example, using a plowshare mixer. Can be performed.

In addition, in the dry mixing process, the conditions may be appropriately determined for homogeneous mixing. For example, when using the plowshare mixer, a stirring speed of 300 to 700 rpm, more specifically 450 to 550 rpm, 3 to 7 minutes, More specifically, it may be performed for 4 to 5 minutes. When performing under the above conditions, it is possible to increase the homogeneous mixing efficiency with citric acid without breaking the superabsorbent polymer particles.

In addition, when the particle size of citric acid is adjusted and used similarly to the particle size distribution of the super absorbent polymer during dry mixing, homogeneous mixing is easy. Specifically, the superabsorbent polymer particles have a particle size of 5 to 15% of 20 mesh or more and less than 30 mesh, 65 to 75% of particle size of 30 mesh or more and less than 50 mesh, and a particle size of 50 to 100 mesh less than 15 mesh The particle size of 20%, and more than 100 meshes may be 0.1 to 3%, so it may be desirable for the dry mixed citric acid to have an equivalent level of particle size.

The antimicrobial superabsorbent polymer according to one embodiment of the invention prepared according to the above-described production method includes: a base resin powder comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acidic group; And a surface crosslinking layer formed on the base resin powder and additionally crosslinked through a non-epoxy watch surface crosslinking agent; including a superabsorbent polymer, an antibacterial agent, and citric acid, wherein the antimicrobial agent comprises a surface of an antibacterial superabsorbent polymer and Homogeneous distribution inside. In the case of the citric acid, homogeneous distribution up to the inside of the superabsorbent polymer when introduced as a surface crosslinking liquid, and homogeneous distribution on the surface of the superabsorbent polymer when introduced through dry mixing.

Accordingly, the antimicrobial superabsorbent polymer can exhibit excellent antimicrobial and deodorizing effects through significantly improved bacterial growth inhibition, along with excellent absorption performance and liquid permeability, and can also exhibit reduced dust number and increased anti-caking rate. .

Specifically, the antimicrobial superabsorbent polymer has a gel permeability under pressure (GPUP) of 22 to 24 식 10E ^-13 m ² calculated according to Equation 1 below. GPUP is usually a parameter indicating the liquid permeability of the super absorbent polymer, and by showing the GPUP in the above-described range, it can exhibit excellent liquid permeability in the diaper.

[Equation 1]

GPUP (ⅹ10E ^-13 m ² )=(Ｋⅹηⅹ10/10000) ⅹ1000000

In Equation 1, η is 0.909% by weight of sodium chloride, the viscosity is 0.0009 Pa·s,

K is a value calculated according to the following equation (2)

[Equation 2]

Ｋ(ⅹ10E ^-7 cm ³ s/g)=(Fg ⅹ t / ρⅹ A ⅹ P)

F _g is the physiological saline weight (g/s) passed through the gel per hour,

t(cm) is the gel thickness ((t1-t0)/10)

ρ is a density of 0.9% by weight sodium chloride 1 g/cm ³ ,

A is the cylinder area used for GPUP measurement is 28.27 cm ² ,

P is the hydrostatic pressure 4920 dyn/cm ² ,

The to and t1 are 2.1 kPa (0.3 psi) of 1.8 kPa (0.3 psi) by adding a superabsorbent polymer 1.8±0.05 g into a cylinder equipped with a piston that gives a load of 0.9 kPa (0.3 psi) When absorbed for 1 hour under the load of ), and the physiological saline composed of 0.9% by weight of sodium chloride aqueous solution is flowed, the weight of the physiological saline passed for 300 seconds from the time when the first drop passes through the swollen gel, t0 Is the height of the piston before the experiment, and t1 is the height of the piston after passing through physiological saline for 300 seconds.

In addition, the antimicrobial superabsorbent polymer may have a centrifugal water retention capacity (CRC) of 25 to 30 g/g, or 27 to 29 g/g. As such, the antimicrobial superabsorbent polymer prepared by the method of one embodiment may exhibit excellent absorbency under no pressure.

The centrifugal water retention capacity (CRC) for the physiological saline can be measured according to the EDANA method WSP 242.3. Specifically, after absorbing the antimicrobial superabsorbent resin into the physiological saline for 30 minutes, the following equation 3 Can be calculated by:

[Equation 3]

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

In Equation 3,

W ₀ (g) is the initial weight (g) of the antimicrobial superabsorbent polymer, and W ₁ (g) does not use an antimicrobial superabsorbent polymer and is absorbed by immersion in physiological saline for 30 minutes, followed by centrifugation. The device weight was measured after dehydration at 250G for 3 minutes, and W ₂ (g) was absorbed by immersing the antibacterial superabsorbent resin in physiological saline at room temperature for 30 minutes, followed by dehydration at 250G for 3 minutes. , It is the weight of the device measured including the antimicrobial superabsorbent resin.

In addition, the antimicrobial superabsorbent polymer may have a pressure absorption capacity (AUP) of 20 to 25 g/g, or 20 to 22 g/g. As such, the antimicrobial superabsorbent polymer can exhibit excellent absorbency even under pressure.

This pressure absorbing capacity (AUP) can be calculated according to Equation 4 below after absorbing the antimicrobial superabsorbent resin into physiological saline under a pressure of 0.7 psi over 1 hour:

[Equation 4]

AUP(g/g) = [W ₄ (g)-W ₃ (g)]/ W ₀ (g)

In Equation 4,

W ₀ (g) is the initial weight of the antimicrobial superabsorbent polymer (g), W ₃ (g) is the sum of the weight of the antimicrobial superabsorbent polymer and the weight of the device capable of applying a load to the antimicrobial superabsorbent polymer, W ₄ (g) is the sum of the weight of the antimicrobial superabsorbent polymer and the weight of the device capable of applying a load to the antimicrobial superabsorbent polymer after absorbing physiological saline in the antimicrobial superabsorbent polymer for 1 hour under a load (0.7 psi). to be.

As such, the antimicrobial superabsorbent polymer can exhibit excellent absorption performance such as basic absorption power and absorption power under pressure.

In addition, the antimicrobial superabsorbent polymer can inhibit the growth of bacteria, reduce the generation of ammonia, and can reduce the discomfort caused by odor compared to the conventional one. In particular, when EDTA or a salt thereof is included as an antibacterial agent, it can exhibit excellent proliferation inhibitory efficacy against Proteus mirabilis bacteria.

In addition, when manufacturing the antimicrobial superabsorbent polymer according to the above manufacturing method, an antimicrobial agent is added through a wet method, and citric acid is additionally used to exhibit high anti-caking efficiency of 90% or more and a low dust number of 1.1 or less.

Specifically, the anti-caking efficiency, 9cm diameter Petri-dish weight is recorded by weight (W1), Petri-dish sample 2±0.01g is uniformly sprayed, and the temperature is set to 40℃ and humidity 80%RH. After putting it in the constant temperature and humidity chamber for 10 minutes, take out the Petri-dish, turn it over on A4 paper and let it stand for 5 minutes, and after 5 minutes, weigh the sample (S1) and Petri-dish (S2) that fell on the floor. It can be calculated according to Equation 5 below.

[Equation 5]

Anti-caking efficiency (%) = [S1/(S2-W1) + S1] ⅹ 100

In addition, the dust generation suppression effect can be calculated according to Equation 6 below using Dustview II (manufactured by Paras GmbH), which can measure the dust of the antimicrobial superabsorbent polymer with a laser.

[Equation 6]

Dust number = Max value + 30 sec. value

In Equation 6, Max value represents the maximum dust value, 30 sec. The value is the value measured 30 seconds after reaching the maximum dust value.

As described above, the antimicrobial superabsorbent polymer obtained according to the method of one embodiment may have excellent antimicrobial properties while maintaining or improving basic physical properties such as water retention capacity and pressurized absorbency required by the superabsorbent polymer, and also in the manufacturing process. The generated dust content is reduced, and anti-caking efficiency can be improved.

Accordingly, according to another embodiment of the present invention, a hygiene product exhibiting excellent antibacterial and deodorizing efficacy may be provided, including the superabsorbent polymer prepared by the above-described manufacturing method and the same.

The hygiene article includes a disposable absorbent product, preferably may include a diaper, and may be a diaper for children or adults. In addition, in the case of the sanitary article, while maintaining basic absorption performance such as water retention capacity and pressure absorption capacity, the antibacterial and deodorizing properties described above are excellent, thereby improving the usability.

According to the present invention, an antimicrobial superabsorbent polymer that exhibits very improved antimicrobial properties against odor-causing bacteria in hygiene products such as diapers for adults and thus deodorant properties is produced without deteriorating basic absorbent performance such as water retention capacity and absorbency under pressure. Can be. In addition, the above manufacturing method can greatly reduce the amount of dust generated during the production of a super absorbent polymer using an antibacterial agent and greatly improve the anti-caking efficiency.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are only illustrative of the present invention and the scope of the present invention is not limited to the following examples.

<Preparation of antibacterial superabsorbent polymer>

Example One

With respect to 100 parts by weight of acrylic acid monomer, 38.9 parts by weight of caustic soda (NaOH) and 103.9 parts by weight of water were mixed, and 0.1 parts by weight of sodium persulfate as a thermal polymerization initiator and diphenyl as a photopolymerization initiator (2,4,6- Trimethylbenzoyl)-phosphine oxide 0.01 parts by weight and a crosslinking agent polyethylene glycol diacrylate 0.3 parts by weight was added to prepare a monomer composition.

The internal temperature of the monomer composition is maintained at 80°C, and UV light is flowed at a flow rate of 243 kg/hr on a polymerization belt of a continuous belt polymerization reactor in which a UV irradiation device having an intensity of 10 mW is installed as a mercury UV lamp light source 1 Irradiation was performed for a minute, and then the polymerization reaction was performed in a light-free state for 2 minutes.

After the polymerization was completed, the gel-type polymerization sheet was first cut using a shredder type cutter, and then coarsely pulverized through a meat chopper. After drying through a hot air dryer for 30 minutes at a temperature of 180 ℃, pulverized using a rotary mixer and classified to 150㎛ to 850㎛ to prepare a base resin.

Based on 100 parts by weight of the base resin, 6 parts by weight of water, 0.45 parts by weight of 1,3-propanediol, 1.0 parts by weight of EDTA-4Na and 0.5 parts by weight of propylene glycol were uniformly mixed to prepare a surface crosslinking solution. After uniformly mixing, the surface treatment reaction was performed at 180° C. for 1 hour to form a surface crosslinking layer.

2 parts by weight of citric acid (corresponding to 1.85 parts by weight based on 100 parts by weight of base resin powder) was added to 100 parts by weight of the superabsorbent polymer on which the surface crosslinked layer was formed, and the mixture was dry stirred at 500 rpm for 5 minutes to obtain an antimicrobial superabsorbent resin. Obtained.

Example 2

Instead of the surface crosslinking solution in Example 1, based on 100 parts by weight of the base resin, 6 parts by weight of water, 0.45 parts by weight of 1,3-propanediol, 1 part by weight of EDTA-4Na, 0.5 parts by weight of propylene glycol and citric acid 1 The surface crosslinking solution prepared by uniformly mixing parts by weight was used, and after the formation of the surface crosslinked layer, a dry mixing process with citric acid was not performed, and the same method as in Example 1 was carried out to obtain antibacterial and antibacterial properties. An absorbent resin was prepared.

Example 3

Instead of the surface crosslinking solution in Example 1, 4 parts by weight of water based on 100 parts by weight of the base resin, 0.45 parts by weight of 1,3-propanediol, 1.0 parts by weight of EDTA-4Na and 0.5 parts by weight of propylene glycol were uniformly mixed. Except for using the prepared surface crosslinking solution, it was carried out in the same manner as in Example 1 to obtain an antibacterial superabsorbent polymer.

Example 4

Instead of the surface crosslinking solution in Example 1, 3 parts by weight of water, 0.45 parts by weight of 1,3-propanediol, 0.5 parts by weight of EDTA-4Na and 0.5 parts by weight of propylene glycol based on 100 parts by weight of the base resin were uniformly mixed. Except for using the prepared surface crosslinking solution, it was carried out in the same manner as in Example 1 to obtain an antibacterial superabsorbent polymer.

Example 5

Instead of the surface crosslinking solution in Example 1, 6 parts by weight of water based on 100 parts by weight of the base resin, 0.45 parts by weight of 1,3-propanediol, 0.25 parts by weight of EDTA-4Na and 0.5 parts by weight of propylene glycol were uniformly mixed. Except for using the prepared surface crosslinking solution, an antibacterial superabsorbent polymer was prepared in the same manner as in Example 1 above.

Example 6

Instead of the surface crosslinking solution in Example 1, 6 parts by weight of water based on 100 parts by weight of the base resin, 0.45 parts by weight of 1,3-propanediol, 0.5 parts by weight of EDTA-4Na and 0.5 parts by weight of propylene glycol were uniformly mixed. It was carried out in the same manner as in Example 1, except for using the surface crosslinking solution prepared by obtaining an antimicrobial superabsorbent polymer.

Example 7

In Example 1, in dry mixing of the superabsorbent polymer having a surface crosslinked layer and citric acid, 3 parts by weight of citric acid with respect to 100 parts by weight of the superabsorbent resin with a surface crosslinked layer was used. It was carried out in the same way to obtain an antibacterial superabsorbent resin.

Example 8

When dry mixing the superabsorbent polymer having a surface crosslinked layer and citric acid in Example 1, 1 part by weight of citric acid (corresponding to 0.93 parts by weight based on 100 parts by weight of the base resin powder) with respect to 100 parts by weight of the superabsorbent resin with a surface crosslinked layer ) Except for using the same method as in Example 1 to obtain an antimicrobial superabsorbent polymer.

Example 9

Instead of the surface crosslinking solution in Example 1, based on 100 parts by weight of the base resin, 6 parts by weight of water, 0.45 parts by weight of 1,3-propanediol, 1 part by weight of EDTA-4Na, 0.5 parts by weight of propylene glycol and 0.5 parts by weight of citric acid Antimicrobial and superabsorbent properties were carried out in the same manner as in Example 1, except that a surface crosslinking solution prepared by uniformly mixing the parts was used, and a dry mixing process with citric acid was not performed after formation of the surface crosslinked layer. Resin was prepared.

Comparative example One

In the preparation of the surface crosslinking solution in Example 1, EDTA-4Na was not used, and after the surface crosslinking layer was formed, a dry mixing process with citric acid was not performed, and the same method as in Example 1 was performed, A super absorbent polymer was prepared.

Specifically, with respect to 100 parts by weight of acrylic acid monomer, 38.9 parts by weight of caustic soda (NaOH) and 103.9 parts by weight of water are mixed, and 0.1 parts by weight of sodium persulfate as a thermal polymerization initiator and diphenyl as a photopolymerization initiator (2, A monomer composition was prepared by adding 0.01 part by weight of 4,6-trimethylbenzoyl)-phosphine oxide and 0.3 part by weight of polyethylene glycol diacrylate as a crosslinking agent.

The internal temperature of the monomer composition is maintained at 80°C, and UV light is flowed at a flow rate of 243 kg/hr on a polymerization belt of a continuous belt polymerization reactor in which a UV irradiation device having an intensity of 10 mW is installed as a mercury UV lamp light source 1 Irradiation was performed for a minute, and then the polymerization reaction was performed in a light-free state for 2 minutes.

After the polymerization was completed, the gel-type polymerization sheet was first cut using a shredder type cutter, and then coarsely pulverized through a meat chopper. After drying through a hot air dryer for 30 minutes at a temperature of 180 ℃, pulverized using a rotary mixer and classified to 150㎛ to 850㎛ to prepare a base resin.

6 parts by weight of water based on 100 parts by weight of the base resin, 0.45 parts by weight of 1,3-propanediol, and 0.5 parts by weight of propylene glycol were uniformly mixed to prepare a surface crosslinking solution, and uniformly mixed with the base resin, The surface treatment reaction was performed at 180° C. for 1 hour to form a surface crosslinking layer to prepare a super absorbent polymer.

Comparative example 2

With respect to 100 parts by weight of the super absorbent polymer prepared in Comparative Example 1, 1 part by weight of EDTA-4Na was added, and dry mixing was performed at 500 rpm for 5 minutes using a Ploughshare mixer to prepare an antibacterial super absorbent polymer.

Comparative example 3

1 part by weight of EDTA-4Na and 600 ppm of mineral oil as a particle size control agent were added to 100 parts by weight of the superabsorbent polymer prepared in Comparative Example 1 and dry mixed at 500 rpm for 5 minutes using a Ploughshare mixer to prepare an antibacterial superabsorbent polymer. Did.

Comparative example 4

Instead of the surface crosslinking solution in Example 1, 3 parts by weight of water, 0.45 parts by weight of 1,3-propanediol, 1 part by weight of EDTA-4Na, 3.5 parts by weight of propylene glycol and 0.23 of oxalic acid based on 100 parts by weight of the base resin The surface crosslinking solution prepared by uniformly mixing parts by weight was used, and after the formation of the surface crosslinked layer, a dry mixing process with citric acid was not performed, and the same method as in Example 1 was carried out to obtain antibacterial and antibacterial properties. An absorbent resin was prepared.

Comparative example 5

In Example 1, instead of the surface crosslinking solution, 6 parts by weight of water based on 100 parts by weight of the base resin, 0.45 parts by weight of 1,3-propanediol, 1.2 parts by weight of EDTA-4Na, and 0.5 parts by weight of propylene glycol were uniformly mixed. By using the prepared surface crosslinking solution, and after the formation of the surface crosslinking layer, except for not performing a dry mixing process with citric acid, was carried out in the same manner as in Example 1 to prepare an antibacterial superabsorbent polymer .

Comparative example 6

An antimicrobial superabsorbent polymer was prepared in the same manner as in Example 1, except that oxalic acid was used in Example 1 in the same content instead of citric acid.

Comparative example 7

In Example 1, except for using 5 parts by weight of citric acid (corresponding to 4.6 parts by weight based on 100 parts by weight of the base resin powder) with respect to 100 parts by weight of the superabsorbent polymer having the surface crosslinked layer formed in Example 1, in Example 1, Antibacterial superabsorbent polymer was prepared by the same method as described above.

Experimental Example

For the antimicrobial superabsorbent resin prepared in the above Examples and Comparative Examples, antimicrobial activity, GPUP, CRC, AUP, anticaking efficiency, and dust number were measured, respectively. The results are shown in Table 1 below.

(1) Antibacterial evaluation

Proteus mirabilis (ATCC29906) was added to 2 g of sample in 50 ml of artificial urine inoculated with 3,100 CFU/ml, and stirred for 1 minute to mix evenly. After incubation in an oven at 35° C. for 12 hours, well washed with 150 ml of brine to measure CFU (colony forming unit).

In addition, only the bacteria were inoculated into artificial urine without the introduction of antibacterial superabsorbent resin, and used as a control.

(2) Gel permeability under pressure (GPUP)

A 400 mesh wire mesh made of stainless steel was mounted on a cylindrical bottom of a plastic cylinder having an inner diameter of 60 mm. On top of that, a piston capable of uniformly giving a load of 2.1 kPa (0.3 psi) was slightly smaller than the outer diameter of 60 mm, and there was no gap with the inner wall of the cylinder, and the height was measured after being positioned unobstructed (t0). After uniformly applying 1.8 ± 0.05 g of absorbent resin to the cylinder and raising the piston, place a glass filter of 90 mm in diameter and 5 mm in thickness inside a petri dish with a diameter of 200 mm, and physiological saline composed of 0.9% by weight sodium chloride from the top side of the glass filter. It was put about 5 mm high and allowed to absorb for 1 hour under load. Thereafter, a physiological saline solution consisting of 0.9% by weight sodium chloride was flowed out, and the hourly weight of the physiological saline solution passed for 300 seconds was measured after the first drop passed through the swollen gel (F _g ). After passing the physiological saline for 300 seconds, the height (t1) of the measuring device was measured, and GPUP was measured according to the following equation.

[Equation 1]

GPUP (ⅹ10E ^-13 m ² )=(Ｋⅹηⅹ10/10000) ⅹ1000000

In Equation 1, η is 0.909% by weight of sodium chloride, the viscosity is 0.0009 Pa·s,

K is a value calculated according to Equation 2 below,

[Equation 2]

Ｋ(ⅹ10E ^-7 cm ³ s/g)=(F _g ⅹ t / ρⅹ A ⅹ P)

In Equation 2, F _g is the physiological saline weight (g/s) passing through the gel per hour,

t(cm) is the gel thickness ((t1-t0)/10)

ρ is a density of 0.9% by weight sodium chloride 1 g/cm ³ ,

A is the cylinder area used for GPUP measurement is 28.27 cm ² ,

P is a hydrostatic pressure of 4920 dyn/cm ² .

(3) Centrifuge Retention Capacity (CRC)

The water retention capacity of each resin by the load-free absorption magnification was measured according to EDANA WSP 241.3.

Specifically, from the antimicrobial superabsorbent polymer obtained through Examples and Comparative Examples, resins classified with a sieve of #30-50 were obtained. After the resin W ₀ (g) (about 0.2 g) was uniformly put in a nonwoven fabric bag and sealed, it was immersed in physiological saline (0.9 wt%) at room temperature. After 30 minutes, the bag was drained for 3 minutes under the condition of 250G using a centrifuge, and the mass W ₂ (g) of the envelope was measured. Moreover, the mass W ₁ (g) at that time was measured after performing the same operation without using a resin. CRC (g/g) was calculated according to the following equation using each obtained mass.

[Equation 3]

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

(4) Absorbency under pressure (AUP)

According to EDANA method WSP 242.3, the absorbency under pressure (AUP) was measured for the antimicrobial superabsorbent polymers prepared in Examples and Comparative Examples.

Specifically, a 400 mesh wire mesh made of stainless steel was mounted on a cylindrical bottom of a plastic having an inner diameter of 60 mm. Under conditions of normal temperature and humidity of 50%, the water absorbent resin W(g) (approximately 0.90 g) was uniformly spread on the wire mesh, and a piston capable of uniformly applying a load of 4.83 kPa (0.7 psi) on it was 60 mm in outer diameter. It is slightly smaller, has no gaps with the inner wall of the cylinder, and prevents vertical movement. At this time, the weight W _a (g) of the device was measured.

A glass filter having a diameter of 90 mm and a thickness of 5 mm was placed inside the petri dish having a diameter of 150 mm, and the physiological saline composed of 0.90% by weight sodium chloride was brought to the same level as the top surface of the glass filter. A sheet of filter paper having a diameter of 90 mm was placed thereon. The measuring device was mounted on a filter paper, and the liquid was absorbed for 1 hour under a load. After 1 hour, the measuring device was lifted, and the weight W _b (g) was measured.

Then, the pressure absorption capacity (g/g) was calculated according to the following equation from W _a and W _b .

[Equation 4]

AUP (g/g) = {W _b -W _a }/W

(5) Dust number

The dust value was analyzed using Dustview II (manufactured by Paras GmbH), which can measure the dust level of the antimicrobial superabsorbent polymer prepared in Examples and Comparative Examples with a laser.

The dust number was measured using the SAP sample prepared in 30 g of the example or the comparative example. The dust number was calculated by the following equation because small particles and certain substances fall at a slower rate than coarse grains.

[Equation 5]

Dust number = Max value + 30 sec. value

In Equation 5, Max value represents the maximum dust value, 30 sec. The value is the value measured 30 seconds after reaching the maximum dust value.

(6) Anti-caking efficiency (A/C efficiency)

Petri-dish weight of 9 cm in diameter was measured and recorded (W1). Sample 2±0.01g was uniformly sprayed onto Petri-dish, and placed in a constant temperature and humidity chamber set at a temperature of 40°C and a humidity of 80%RH, and allowed to stand for 10 minutes. After 10 minutes, the Petri-dish was taken out and turned over on A4 paper and left for 5 minutes. After 5 minutes, the weight of the sample dropped on the floor (S1) and the weight of the Petri-dish (S2) were accurately recorded. The anti-caking efficiency (A/C efficiency) was calculated according to the following equation using the measured value.

[Equation 6]

Anti-caking efficiency (%) = [S1/(S2-W1) + S1] ⅹ 100

Incubation time
(h) CFU/ml Dust number A/C efficiency
(%) CRC
(g/g) AUP
(g/g) GPUP
(Ⅹ10 ^-13 m ² ) Control
0
(Initial inoculation bacteria) 3100 - - - - - 12 8,600,000,000 - - - - - Example 1 12 450,000 1.0 90 27.6 20.4 23 Example 2 12 500,000 1.0 90 28.1 20.3 24 Example 3 12 450,000 1.0 90 28.0 20.7 24 Example 4 12 1,500,000 1.0 90 28.2 20.4 23 Example 5 12 2,000,000 1.0 90 28.1 20.4 23 Example 6 12 1,400,000 1.0 90 28.0 20.5 24 Example 7 12 400,000 1.0 90 27.0 20.0 22 Example 8 12 450,000 1.0 90 27.4 20.4 23 Example 9 12 550,000 1.0 90 28.1 20.3 24 Comparative Example 1 12 14,000,000,000 1.1 30 28.5 20.2 21 Comparative Example 2 12 3,900,000 18 16 27.6 19.0 20 Comparative Example 3 12 23,000,000 1.1 22 27.5 19.2 20 Comparative Example 4 12 1,500,000 1.0 80 28.4 20.1 23 Comparative Example 5 12 650,000 1.0 85 28.6 20.2 24 Comparative Example 6 12 1,200,000 2.0 80 26.4 18.1 20 Comparative Example 7 12 900,000 3.0 75 24.0 17.0 19

As a result of the experiment, the antimicrobial superabsorbent polymers of Examples 1 to 9 prepared by the production method according to the present invention exhibited an effect of improving liquid permeability and antimicrobial properties, along with excellent absorption performance, and reduced dust generation and increased A/C efficiency. Showed the effect of. In particular, Examples 1 to 9, Comparative Example 1 without antibacterial and citric acid treatment, Comparative Example 2 prepared by dry mixing of the antimicrobial agent, and Comparative Example 3 prepared by dry mixing of the antimicrobial agent with the particle size control agent, the same level While exhibiting the above excellent absorption performance and liquid permeability, it exhibited a markedly improved effect in terms of antibacterial properties and A/C efficiency.

It can be seen from the experimental results of Examples 1, 5, and 6 that the antimicrobial improvement effect increases as the content of the antibacterial agent increases. In addition, from the results of Examples 1, 7, and 8, as the content of citric acid introduced through dry mixing increased, and as the contents of citric acid contained in the surface crosslinking solution increased from Examples 2 and 9, the antibacterial effect was improved. You can see that it increases.

However, from the results of Comparative Example 7, when the input amount of citric acid exceeds 3 parts by weight based on 100 parts by weight of the base resin powder, the antimicrobial improvement effect is not great, and the absorption performance and liquid permeability decrease and the generation amount of dust is greatly increased. It can be seen that the A/C efficiency is lowered. In addition, it can be seen from the results of Comparative Example 5 that even if the antibacterial agent is treated at a higher concentration, when the citric acid treatment is not performed, the antimicrobial improvement effect is not large and the A/C efficiency is greatly reduced due to the untreated citric acid. From these results, it is possible to obtain the effect of improving the antimicrobial improvement effect and reducing the amount of dust generation and A/C efficiency through the treatment of citric acid, but this improvement effect can be realized within the optimum content range. .

In addition, from the results of Example 1 and Comparative Example 6, when using oxalic acid instead of citric acid, the antimicrobial improvement effect is negligible, dust generation increases, A/C efficiency decreases, and the produced antibacterial superabsorbent resin is an example. It can be seen that it does not exhibit the level of absorption performance and liquid permeability.

Claims (10)

Crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized in the presence of an internal crosslinking agent to form a hydrogel polymer comprising a crosslinked polymer;
Drying, grinding and classifying the hydrogel polymer to form a base resin powder; And
A method for producing an antimicrobial superabsorbent polymer comprising mixing and reacting a surface crosslinking liquid containing a non-epoxy watch surface crosslinking agent, an antibacterial agent, and water with the base resin powder to form a surface crosslinking layer,
In the manufacturing method, when the surface crosslinking layer is formed, citric acid is additionally added to the surface crosslinking solution to form a surface crosslinking layer; Or after the formation of the surface cross-linking layer further comprises the step of dry mixing with the superabsorbent polymer is formed by adding a citric acid to the surface cross-linking layer,
The citric acid is added in an amount of 0.1 to 3 parts by weight based on the total weight of the base resin powder,
Preparation of an antimicrobial superabsorbent polymer having a gel permeability (GPUP) under pressure calculated according to Equation 1 below is 22 to 24 ⅹ 10E ^-13 m ² , and an anticaking efficiency calculated according to Equation 5 below is 90% or more. Way.
[Equation 1]
GPUP (ⅹ10E ^-13 m ² )=(Ｋⅹηⅹ10/10000) ⅹ1000000
In Equation 1, η is 0.909% by weight of sodium chloride, the viscosity is 0.0009 Pa·s,
K is a value calculated according to Equation 2 below,
[Equation 2]
Ｋ(ⅹ10E ^-7 cm ³ s/g)=(F _g ⅹ t / ρⅹ A ⅹ P)
In Equation 2, F _g is the physiological saline weight (g/s) passing through the gel per hour,
t(cm) is the gel thickness ((t1-t0)/10)
ρ is a density of 0.9% by weight sodium chloride 1 g/cm ³ ,
A is the cylinder area used for GPUP measurement is 28.27 cm ² ,
P is the hydrostatic pressure 4920 dyn/cm ² ,
The to, and t1, 2.1 kPa (0.3 psi) to the cylinder equipped with a piston imparting a superabsorbent polymer 1.8±0.05g, physiological saline composed of 0.9% by weight of sodium chloride aqueous solution was poured 2.1 kPa (0.3 psi) for 1 hour under load, and when measuring the weight of the physiological saline that has passed for 300 seconds from the time when the first drop passes through the swollen gel while flowing a saline solution consisting of 0.9% by weight of sodium chloride aqueous solution, t0 is the height of the piston before the experiment, t1 is the height of the piston after passing through saline for 300 seconds,
[Equation 5]
Anti-caking efficiency (%) = [S1/(S2-W1) + S1] ⅹ 100
In Equation 5, W1 is a 9cm diameter Petri-dish weight used when measuring anti-caking efficiency, and S1 contains 2±0.01g of a sample of an antimicrobial superabsorbent polymer in the Petri-dish, temperature 40℃, humidity 80% After putting it in the RH constant temperature and humidity chamber for 10 minutes, the Petri-dish is taken out, inverted to A4 paper and left for 5 minutes, and after 5 minutes, the weight of the sample dropped on the floor, S2 is the weight of the Petri-dish at this time.
According to claim 1,
The citric acid is added to the surface crosslinking liquid in an amount of 0.5 to 2 parts by weight based on 100 parts by weight of the base resin powder when the surface crosslinking layer is formed.
According to claim 1,
After the step of forming the surface crosslinking layer, the citric acid is added in 0.5 to 3 parts by weight based on 100 parts by weight of the superabsorbent polymer on which the surface crosslinking layer is formed.
According to claim 1,
The surface cross-linking solution comprises a non-epoxy clock surface cross-linking agent 0.01 to 5 parts by weight, 0.1 to 1.5 parts by weight of antibacterial agent and 0.5 to 10 parts by weight of water with respect to 100 parts by weight of the base resin powder, a method for producing an antimicrobial superabsorbent polymer.
According to claim 1,
The antimicrobial agent comprises ethylenediamine-N,N,N',N'-tetraacetic acid or a salt thereof, a method for producing an antimicrobial superabsorbent polymer.
According to claim 1,
The antibacterial agent comprises ethylenediamine-N,N,N',N'-tetraacetic acid, tetrasodium salt (EDTA-4Na), a method for producing an antimicrobial superabsorbent polymer.
According to claim 1,
The non-epoxy watch surface crosslinking agent has a polyhydric alcohol compound having 3 to 20 carbon atoms, a polyamine compound, a halo epoxy compound and a condensation product thereof, an oxazoline-based compound, a mono-, di- and poly-oxazolidinone compound, a cyclic urea compound, a polyvalent A method for producing an antimicrobial superabsorbent polymer comprising at least one compound selected from the group consisting of a metal salt and an alkylene carbonate compound having 2 to 5 carbon atoms.
According to claim 1,
The step of forming the surface crosslinking layer is carried out at a temperature of 170 to 200 ℃, a method for producing an antimicrobial superabsorbent polymer.
According to claim 1,
The water-soluble ethylenically unsaturated monomers are acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2-(meth)acryloyl Propanesulfonic acid, or anionic monomers of 2-(meth)acrylamide-2-methyl propane sulfonic acid and salts thereof; (Meth)acrylamide, N-substituted (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate or polyethylene glycol ( Nonionic hydrophilic containing monomers of meth)acrylates; And an amino group-containing unsaturated monomer of (N,N)-dimethylaminoethyl (meth)acrylate or (N,N)-dimethylaminopropyl (meth)acrylamide and a quaternized product thereof. A method for producing an antimicrobial superabsorbent polymer comprising:
According to claim 1,
The antimicrobial superabsorbent polymer is Proteus mirabilis (Proteus mirabilis) inhibits the growth of bacteria, antibacterial superabsorbent polymer production method.