Preparation method for super absorbent polymer particle

Abstract

The present invention relates to a method for manufacturing superabsorbent resin particles, and more specifically, to a method for manufacturing spherical superabsorbent resin particles that are suitable for use as encapsulating materials for organic light-emitting diodes due to their excellent hygroscopicity, solvent dispersibility, and optical properties.

Description

Technology Field

[0001] The present invention relates to a method for manufacturing superabsorbent resin particles. Background Technology

[0002] Organic electronic devices are devices containing organic materials capable of generating an alternating current of electric charge using holes and electrons; examples include photovoltaic devices, rectifiers, transmitters, and organic light-emitting devices (OLEDs). One of the major issues in the commercialization and expansion of applications of such organic electronic devices is durability. This is because the organic materials and metal electrodes included in the organic electronic devices are easily oxidized by external factors such as moisture.

[0004] Accordingly, research is being conducted on encapsulating materials to block the penetration of external factors, such as oxygen or moisture, into organic electronic devices. In particular, for transparent panels, it is necessary to ensure transparency along with the hygroscopicity of the encapsulating material; however, the development of encapsulating materials that satisfy these requirements is still lagging.

[0006] Accordingly, there is still a demand for packaging materials that can exhibit excellent moisture absorption while simultaneously maintaining transparency. The problem to be solved

[0008] In addition, the present invention aims to provide a method for manufacturing superabsorbent resin particles capable of producing nano-sized spherical superabsorbent resin particles with excellent absorbency and solvent dispersibility.

[0009] In addition, the present invention aims to provide a packaging material composition comprising the above-mentioned superabsorbent resin particles having excellent absorbency and improved transparency. means of solving the problem

[0011] In order to solve the above problem, the present invention,

[0012] A first step of preparing a polyacrylic acid composition by mixing polyacrylic acid in an aqueous solvent;

[0013] A second step of preparing a dispersed phase solution by mixing a polyvalent epoxy-based crosslinking agent with the above polyacrylic acid composition;

[0014] A third step of preparing a water-in-oil emulsion (W / O emulsion) by mixing a continuous phase solution containing a nonionic surfactant and an isoparaffinic hydrocarbon solvent with the dispersed phase solution; and

[0015] A fourth step of producing superabsorbent resin particles by carrying out a cross-linking reaction within a droplet of the above W / O emulsion; comprising

[0016] The above dispersed phase solution and the above continuous phase solution are used in a volume ratio of 1:15 to 1:25,

[0017] A method for manufacturing superabsorbent resin particles is provided.

[0019] In addition, the present invention provides a packaging material composition comprising superabsorbent resin particles manufactured according to the manufacturing method described above; and a resin component. Effects of the invention

[0021] The method for manufacturing superabsorbent resin particles according to the present invention has the advantage of being able to manufacture superabsorbent resin particles with improved hygroscopicity, solvent dispersibility, and optical properties by manufacturing spherical superabsorbent resin particles into nano-sized particles and increasing the specific surface area of ​​the particles. Brief explanation of the drawing

[0023] Figure 1 is an FE-SEM image of the superabsorbent resin particles of Example 1. Figure 2 is an FE-SEM image of the superabsorbent resin particles of Example 2. Figure 3 is an FE-SEM image of the superabsorbent resin particles of Example 3. Figure 4 is an FE-SEM image of the superabsorbent resin particles of Example 4. Figure 5 is an FE-SEM image of the superabsorbent resin particles of Comparative Example 1. Figure 6 is an FE-SEM image of the superabsorbent resin particles of Comparative Example 3. Figure 7 is an FE-SEM image of the superabsorbent resin particles of Comparative Example 4. Figure 8 is an FE-SEM image of the superabsorbent resin particles of Comparative Example 5. Specific details for implementing the invention

[0024] In the present invention, terms such as first, second, etc. are used to describe various components, and these terms are used solely for the purpose of distinguishing one component from another component.

[0025] Furthermore, the terms used herein are used merely to describe exemplary embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “comprising,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, components, or combinations thereof.

[0026] Furthermore, in the present invention, when each layer or element is referred to as being formed "on" or "above" each layer or element, it means that each layer or element is formed directly on each layer or element, or that another layer or element may be additionally formed between each layer, on an object, or on a substrate.

[0027] The present invention is capable of various modifications and may take various forms, and specific embodiments are illustrated and described in detail below. However, this is not intended to limit the invention to the specific disclosed forms, and it should be understood that the invention includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0028] Hereinafter, a method for manufacturing superabsorbent resin particles and a packaging material composition will be described in more detail according to specific embodiments of the invention.

[0029] Prior to this, the technical terms used in this specification are intended merely to refer to specific embodiments and are not intended to limit the invention. Furthermore, the singular forms used herein include plural forms unless the phrases clearly indicate otherwise.

[0031] According to one embodiment of the invention, a method for manufacturing superabsorbent resin particles is provided, comprising the following steps:

[0032] A first step of preparing a polyacrylic acid composition by mixing polyacrylic acid in an aqueous solvent;

[0033] A second step of preparing a dispersed phase solution by mixing a polyvalent epoxy-based crosslinking agent with the above polyacrylic acid composition;

[0034] A third step of preparing a water-in-oil emulsion (W / O emulsion) by mixing a continuous phase solution containing a nonionic surfactant and an isoparaffinic hydrocarbon solvent with the dispersed phase solution; and

[0035] Step 4: Producing superabsorbent resin particles by carrying out a cross-linking reaction within a droplet of the above W / O emulsion.

[0036] At this time, the dispersed phase solution and the continuous phase solution are used in a volume ratio of 1:15 to 1:25.

[0038] Generally, superabsorbent polymers are manufactured by obtaining a hydrogel polymer through bulk polymerization or suspension polymerization of water-soluble hygroscopic acrylic acid monomers with a crosslinking agent in the presence of a polymerization initiator. However, hydrogel polymers produced by this method undergo irreversible aggregation of particles due to a large number of hydrophilic groups on the surface. Nevertheless, securing a specific surface area above a certain level is essential for improving absorption performance; consequently, to reduce particle size to the micrometer level, the hydrogel polymer is crushed using physical force and then dried for use.

[0040] However, in order to use the above-described packaging material, the superabsorbent resin particles must be dispersed in a resin component to form a composition; however, these micrometer-sized superabsorbent resin particles suffer from the problem of settling within the resin over time, which reduces the dispersibility of the superabsorbent resin particles within the composition and consequently lowers the transparency of the packaging material produced from the composition. Furthermore, in the case of conventional superabsorbent resin particles physically crushed to micrometer size, their shape is non-spherical and their size is non-uniform, which can further reduce the transparency of the packaging material produced from a composition containing them.

[0042] Accordingly, the inventors have completed the present invention by confirming that it is possible to produce spherical superabsorbent resin particles having a nanometer particle size by crosslinking a polyacrylic acid polymer within a droplet of a water-in-oil emulsion without a polymerization process of an acrylic acid-based monomer using an initiator. In addition, these superabsorbent resin particles can be evenly dispersed without settling within a composition containing a resin component, thereby improving the transparency of the encapsulating material produced from the composition.

[0044] In addition, when the above W / O emulsion satisfies a specific volume ratio of the dispersed phase solution and the continuous phase solution, it is possible to manufacture highly absorbent resin particles with excellent moisture absorption capacity, initial absorption rate, moisture resistance, and solvent dispersibility.

[0046] Method for manufacturing superabsorbent resin particles

[0047] The superabsorbent resin particles of one embodiment are manufactured by including the following steps:

[0048] A first step of preparing a polyacrylic acid composition by mixing polyacrylic acid in an aqueous solvent;

[0049] A second step of preparing a dispersed phase solution by mixing a polyvalent epoxy-based crosslinking agent with the above polyacrylic acid composition;

[0050] A third step of preparing a water-in-oil emulsion (W / O emulsion) by mixing a continuous phase solution containing a nonionic surfactant and an isoparaffinic hydrocarbon solvent with the dispersed phase solution; and

[0051] Step 4: Producing superabsorbent resin particles by carrying out a cross-linking reaction within a droplet of the above W / O emulsion.

[0053] Below, each step is explained in detail.

[0055] (Stage 1)

[0056] The first step above is to prepare a polyacrylic acid composition by mixing polyacrylic acid with an aqueous solvent.

[0057] At this time, the polyacrylic acid is used in an amount of 1 to 10% w / v based on the total volume of the dispersed phase solution prepared in the second step. If the polyacrylic acid is used in an amount lower than the above amount, there may be a problem with reduced particle recovery efficiency, and if it is used in an amount higher than the above amount, the stability of the emulsion is reduced and aggregation is accelerated, making it difficult to manufacture superabsorbent resin particles that have a nanometer size and exhibit a spherical shape. More preferably, the polyacrylic acid may be used in an amount of 1% w / v or more, 2% w / v or more, 3% w / v or more, or 4% w / v or more, and 10% w / v or less, 9% w / v or less, 8% w / v or less, or 7% w / v or less, based on the total volume of the dispersed phase solution prepared in the second step.

[0059] In addition, the polyacrylic acid may have a weight-average molecular weight (Mw) of 100,000 to 300,000 g / mol. If the weight-average molecular weight of the polyacrylic acid is excessively low, there may be a problem where the physical aggregation between polymer chains is minimal, resulting in low crosslinking efficiency; if it is excessively high, there may be a problem where the viscosity of the dispersed phase increases, making it impossible to produce a stable emulsion. For example, the polyacrylic acid may have a weight-average molecular weight (Mw, g / mol) of 100,000 or more, 150,000 or more, or 200,000 or more, and 300,000 or less, 280,000 or less, or 260,000 or less.

[0061] At this time, the weight-average molecular weight (Mw) of the polyacrylic acid can be measured using gel permeation chromatography (GPC) with polyacrylate-sodium salt (PAA-Na) as a standard sample for calibration. More specifically, 200 mg of the polyacrylic acid can be diluted in 200 mL of N,N-Dimethylformamide (DMF) solvent to prepare a sample of approximately 1000 ppm, and then the weight-average molecular weight can be measured using an Agilent 1200 series GPC instrument with a flow of 1 mL / min through an RI detector. At this time, the molecular weight of the sample can be calculated based on a calibration curve prepared using eight types of standard PAA-Na.

[0063] In addition, the above polyacrylic acid and a basic solution may be added together so that at least some of the acidic groups of the polyacrylic acid in the polyacrylic acid composition are neutralized.

[0064] As the above basic solution, a base commonly used for neutralization, such as sodium hydroxide or potassium hydroxide, may be used. At this time, the degree of neutralization of the polyacrylic acid may be 0 to 90%, that is, all of the carboxylic acid groups contained in the polyacrylic acid may not be neutralized, or some of them may be neutralized.

[0066] In addition, the above aqueous solvent contains water, and may further include an aqueous sodium chloride solution or an aqueous potassium chloride solution, etc., in addition to water.

[0068] (Stage 2)

[0069] The second step above is a step of preparing a dispersed phase solution by mixing a polyvalent epoxy crosslinking agent with the polyacrylic acid composition, wherein the dispersed phase solution refers to a solution capable of forming a dispersed phase that is surrounded by a continuous phase in the form of droplets in the W / O emulsion prepared in the third step described later.

[0071] Here, the term "polyvalent epoxy crosslinking agent" refers to a compound containing two or more functional groups, namely epoxy groups, that can react with the carboxyl groups of the polyacrylic acid, and may be a diepoxy compound or a triepoxy compound.

[0073] More specifically, the polyvalent epoxy crosslinking agent may be a chain-type aliphatic diepoxy compound, and such a diepoxy compound is desirable in terms of controlling the degree of crosslinking. That is, the epoxy crosslinking agent reacts with the carboxyl groups of polyacrylic acid; however, in the case of polyvalent epoxy, due to steric hindrance, it cannot fully participate in the crosslinking reaction and the reaction terminates as it undergoes hydrolysis and transforms into an -OH functional group. In other words, since the efficiency of the crosslinking reaction is reduced and the hygroscopicity of the particles is also lowered, it is advantageous to use a diepoxy compound.

[0075] For example, the above polyvalent epoxy crosslinking agent may be one or more diepoxy compounds selected from the group consisting of 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl diglycidyl ether, resorcinol diglycidyl ether, diethylene glycol diglycidyl ether, and ethylene glycol diglycidyl ether.

[0077] In addition, the polyvalent epoxy-based crosslinking agent may be used in an amount of 10 to 500 parts by weight relative to 100 parts by weight of the polyacrylic acid. If the content of the crosslinking agent is excessively low, crosslinking may not occur sufficiently, making it difficult to achieve strength above an appropriate level; if the content of the crosslinking agent is excessively high, the crosslinking density may increase, making it difficult to achieve the desired water retention capacity. For example, the polyvalent epoxy-based crosslinking agent may be used in an amount of 15 parts by weight or more, 20 parts by weight or more, or 25 parts by weight or more relative to 100 parts by weight of the polyacrylic acid, while being 500 parts by weight or less, 400 parts by weight or less, or 350 parts by weight or less.

[0079] (Stage 3)

[0080] The third step above is a step of preparing a water-in-oil emulsion by mixing a continuous phase solution containing a nonionic surfactant and an isoparaffinic hydrocarbon solvent with the dispersed phase solution. In this case, the term "continuous phase solution" refers to a solution capable of forming a continuous phase, which is a continuous phase in the W / O emulsion prepared in the above step.

[0082] Here, nonionic surfactants refer to surfactants that are soluble in water without ionizing, and mainly include polymers synthesized by block polymerization or graft polymerization between hydrophobic and hydrophilic monomers, such as polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, polyoxyethylene alkylphenol ethers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, and sucrose fatty acid esters. When using the nonionic surfactant when preparing the continuous phase solution, the solubility in the continuous phase is higher compared to when using cationic and / or anionic surfactants, and it is advantageous in terms of ensuring W / O emulsion stability. In addition, regarding solubility in the continuous phase and ensuring W / O emulsion stability, the HLB (Hydrophile-Lipophile Balance) value of the nonionic surfactant may be 1 to 7.

[0084] For example, a sorbitan fatty acid ester compound may be used as the above-mentioned nonionic surfactant. For example, the above-mentioned nonionic surfactant may be one or more sorbitan fatty acid ester compounds selected from the group consisting of sorbitan monooleate, sorbitan monolaurate, sorbitan monostearate, sorbitan monopalmitate, sorbitan tristearate, and sorbitan sesquioleate.

[0086] In addition, the nonionic surfactant may be used in an amount of 1 to 10% w / v based on the total volume of the continuous phase solution. If the nonionic surfactant is used in an excessively small amount based on the total volume of the continuous phase, there may be a problem in that the interface of the W / O emulsion becomes unstable and the sphericity rate decreases, and if it is used in an excessive amount, residual surfactant adsorbed on the particle surface may remain even after washing. For example, the nonionic surfactant may be 1.2% w / v or more, 1.5% w / v or more, or 2% w / v or more based on the total volume of the continuous phase solution, and 8% w / v or less, 7% w / v or less, or 6% w / v or less.

[0088] In addition, the above-mentioned isoparaffin hydrocarbon refers to a branched alkane compound in which an alkyl group is bonded to a side chain. It is distinguished from n-paraffin hydrocarbons, which are linear alkane compounds in which no substituent is bonded to the side chain, and also differs structurally from cyclic hydrocarbons. When isoparaffin hydrocarbons are used as the solvent for the continuous phase solution, it is preferable compared to when n-paraffin hydrocarbons are used because the intermolecular van der Waals bonds are weak and the viscosity is low, making recovery after particle preparation easier. On the other hand, in the case of cyclic hydrocarbons, the viscosity is lower than that of the dispersed phase, making it difficult to form a stable emulsion, and there is a problem that flocculation between particles can easily occur.

[0090] More specifically, the isoparaffinic hydrocarbon may be an isoparaffinic hydrocarbon having 8 to 20 carbon atoms.

[0092] In addition, the above isoparaffinic hydrocarbon solvent may have a viscosity of 1 to 10 mPa·s at 25°C as measured according to ASTM D 445. For example, the above isoparaffinic hydrocarbon solvent may have a viscosity (mPa·s) of 1 or more, 1.5 or more, or 2 or more, and 10 or less, 8 or less, 6 or less, or 4 or less as measured according to ASTM D 445.

[0094] Meanwhile, the dispersed phase solution and the continuous phase solution may be used in a volume ratio of 1:15 to 1:25. If the continuous phase solution is used in a volume less than 15 times that of the dispersed phase solution, or if the continuous phase solution is used in a volume exceeding 25 times that of the dispersed phase solution, there is a problem in that a stable W / O emulsion is not formed, and spherical superabsorbent resin particles are not formed. Furthermore, superabsorbent resin particles prepared in a W / O emulsion that deviates from the volume ratio of the dispersed phase solution and the continuous phase solution not only have a reduced initial moisture absorption rate but also poor dispersibility in solvents, making it difficult to expect improvement in transparency when applied to encapsulating materials. More specifically, the dispersed phase solution and the continuous phase solution may be used in a volume ratio of 1:15.5 or more, 1:16 or more, or 1:16.5 or more, and 1:25 or less, 1:23 or less, 1:20 or less, or 1:19 or less.

[0096] The mixing of the continuous phase solution and the dispersed phase solution can be carried out by a stirrer using mechanical energy, such as a commonly known homogenizer, colloid mill, or ultra-high-speed mixer, which can sufficiently mix the two solutions to disperse the dispersed phase within the continuous phase, or by ultrasonic treatment. Additionally, the mixing of the continuous phase solution and the dispersed phase solution can be carried out at room temperature of 25°C, and it is preferable to carry out the mixing under nitrogen purging conditions.

[0098] (Stage 4)

[0099] The fourth step above is a step of producing superabsorbent resin particles by carrying out a crosslinking reaction within a droplet of the W / O emulsion. Here, a droplet refers to a dispersed phase surrounded by a surfactant located at the interface between the continuous phase and the dispersed phase. In addition, a polymerization initiator typically used for the polymerization of monomers may not be used in the crosslinking reaction.

[0101] The crosslinking reaction in the above step can be performed by stirring at 300 to 1000 rpm. Additionally, the crosslinking reaction in the above step can be performed at a temperature of 20 to 100 ℃ for 2 to 72 hours. When the crosslinking reaction is performed under the above conditions, it is possible to manufacture perfectly spherical superabsorbent resin particles with a nanometer particle size and uniform size.

[0103] Specifically, the superabsorbent resin particles may have a particle size of 3 μm or less. At this time, the particle size may be the diameter of the superabsorbent resin particles. More specifically, the particle size of the superabsorbent resin particles may be 10 nm or more, 100 nm or more, 200 nm or more, or 400 nm or more, and 2 μm or less, 1.5 μm or less, or 1.2 μm or less.

[0105] At this time, the particle size can be determined by drying the superabsorbent resin particles in a vacuum oven at room temperature, then taking an image of the external surface of the superabsorbent resin particles at a magnification of 1,000 to 35,000 using an FE-SEM (Field Emission Scanning Electron Microscope, product name: S-4800, manufacturer: Hitachi), measuring the diameter of 50 particles from the captured image, and determining the average value thereof.

[0107] In addition, the superabsorbent resin particles may have a sphericity of 70% or more, more preferably 80% or more. At this time, it can be understood that the closer the sphericity is to 100%, the more spherical the particle appears. Here, the sphericity can be measured by drying the superabsorbent resin particles in a vacuum oven at room temperature, then taking an image of the external surface of the superabsorbent resin particles at a magnification of 1,000 to 35,000 using an FE-SEM (Field Emission Scanning Electron Microscope, product name: S-4800, manufacturer: Hitachi), quantifying the relative sphericity based on a particle that is perfectly spherical, i.e., has a sphericity of 100%, for 50 particles in the captured image, and then measuring the average value thereof.

[0109] In addition, after the above fourth step,

[0110] A step of recovering the superabsorbent resin particles from the above W / O emulsion;

[0111] A step of washing the recovered superabsorbent resin particles; and

[0112] It may further include a step of drying the washed superabsorbent resin particles.

[0114] At this time, the washing of the particles can be performed in two steps: first, by washing with ethanol, and second, by washing with hexane / ethanol (volume ratio 1:1).

[0116] Bag material composition

[0117] Meanwhile, according to another aspect, a packaging material composition is provided comprising superabsorbent resin particles manufactured according to the manufacturing method described above; and a resin component.

[0119] Here, the encapsulation material composition refers to a composition that can be used as an encapsulation material to prevent organic materials contained in an organic electronic device (OED) from deteriorating due to external factors such as moisture, and examples of organic electronic devices include photovoltaic devices, rectifiers, transmitters, and organic light emitting devices (OLEDs).

[0121] The above-mentioned superabsorbent resin particles can protect organic materials within an organic electronic device by absorbing or adsorbing moisture or humidity introduced from the outside in the above-mentioned encapsulation composition.

[0123] As the resin component, a resin known to be applicable to the encapsulation of an organic electronic device may be used. More specifically, the resin component is a curable resin or a non-curable resin. For example, the resin component may include one or more selected from the group consisting of epoxy resins, acrylic resins, and olefin resins.

[0125] In addition, the above-mentioned encapsulating composition may further include a solvent to facilitate easy application of the encapsulating composition. In this case, commonly known solvents may be used, for example, pentane, hexane, cyclohexane, benzene, toluene, chloroform, diethyl ether, cyclopentane, 1,4-dioxane, or dichloromethane.

[0127] Such a packaging material composition can be manufactured by mixing the above components in a known manner.

[0129] In addition, the above-mentioned encapsulation composition can be usefully used for encapsulating organic light-emitting diodes in terms of its absorbency and transparency.

[0131] The operation and effects of the invention will be described in more detail below through specific embodiments. However, these embodiments are merely examples of the invention and do not define the scope of the invention.

[0133] <Example>

[0134] Example 1: Preparation of superabsorbent resin particles

[0135] A polyacrylic acid composition was prepared by diluting 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) with 12 mL of DI water.

[0136] Next, 3.2 mL of 1,4-butanediol diglycidyl ether (BDDE, density at 25°C 1.1 g / mL), a polyvalent epoxy crosslinking agent (1.15 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0137] Next, a continuous phase solution was prepared by mixing 16.8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 320 ml of the isoparaffinic hydrocarbon solvent Isopar™ M (IPM, manufactured by ExxonMobil, viscosity at 25°C measured according to ASTM D 445 standard 2.06 mPa·s).

[0138] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0139] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0140] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0142] Example 2: Preparation of superabsorbent resin particles

[0143] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 12 mL of DI water, and 0.40 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0144] Next, 3.2 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (1.15 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0145] Next, a continuous phase solution was prepared by mixing 16.8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 320 ml of the isoparaffinic hydrocarbon solvent Isopar™ M (manufactured by ExxonMobil).

[0146] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0147] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0148] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0150] Example 3: Preparation of superabsorbent resin particles

[0151] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 12 mL of DI water, and 0.80 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0152] Next, 0.32 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (0.115 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0153] Next, a continuous phase solution was prepared by mixing 8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 320 ml of the isoparaffinic hydrocarbon solvent Isopar™ M (manufactured by ExxonMobil).

[0154] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0155] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0156] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0158] Example 4: Preparation of superabsorbent resin particles

[0159] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 12 mL of DI water, and 0.60 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0160] Next, 0.32 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (0.115 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0161] Next, a continuous phase solution was prepared by mixing 8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 320 ml of the isoparaffinic hydrocarbon solvent Isopar™ M (manufactured by ExxonMobil).

[0162] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0163] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0164] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0166] Comparative Example 1: Preparation of superabsorbent resin particles

[0167] 10 g of acrylic acid in monomeric form was neutralized using 15 ml of 26 wt% NaOH solution.

[0168] Subsequently, 0.35 g of the crosslinking agent methylene bisacrylamide (N,N'-Methylenebisacrylamide; MBA) (0.016 mol relative to 1 mol of AA) was added to the neutralized solution and dissolved, and then 0.125 g of the initiator ammonium sulfate (APS) was added and mixed to prepare a dispersed phase solution.

[0169] Next, a continuous phase solution was prepared by adding 10 g of a mixture of surfactants Span 80 and Tween 80 (weight ratio 75:25) to 340 ml of liquid paraffin (Liquid paraffin, product name, manufactured by Daejeong Hwakum Co., Ltd.).

[0170] Next, the mixture was high-speed stirred to form an emulsion, and then polymerized at 70°C for 18 hours.

[0171] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, washed with n-hexane, and then vacuum dried at 40°C at a pressure of 180 mmHg using a rotary evaporator to obtain final superabsorbent resin particles in the form of white powder.

[0173] Comparative Example 2: Preparation of Superabsorbent Resin Particles

[0174] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 12 mL of DI water, and 0.60 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0175] Next, 0.32 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (0.115 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0176] Next, a continuous phase solution was prepared by mixing 8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 320 ml of liquid paraffin solvent.

[0177] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0178] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0179] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0181] Comparative Example 3: Preparation of Superabsorbent Resin Particles

[0182] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 12 mL of DI water, and 0.60 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0183] Next, 0.32 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (0.115 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0184] Next, a continuous phase solution was prepared by mixing 8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 240 ml of liquid paraffin solvent.

[0185] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0186] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0187] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0189] Comparative Example 4: Preparation of superabsorbent resin particles

[0190] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 12 mL of DI water, and 0.60 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0191] Next, 0.32 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (0.115 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0192] Next, a continuous phase solution was prepared by mixing 1.3 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 240 ml of liquid paraffin solvent.

[0193] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0194] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0195] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0197] Comparative Example 5: Preparation of superabsorbent resin particles

[0198] 4 mL of 25 wt% polyacrylic acid (PAA, weight-average molecular weight: 240,000 g / mol, density at 25°C 1.09 g / mL, manufactured by Sigma-Aldrich) was diluted with 4 mL of DI water, and 0.40 mL of 50 wt% NaOH solution was added to prepare a polyacrylic acid composition in which the carboxylic acid groups of the polyacrylic acid are neutralized.

[0199] Next, 0.32 mL of 1,4-butanediol diglycidyl ether (BDDE), a polyvalent epoxy crosslinking agent (0.115 mol per 1 mol of acrylic acid repeating unit in PAA), was added to the prepared polyacrylic acid composition and mixed to prepare a dispersed phase solution.

[0200] Next, a continuous phase solution was prepared by mixing 8 g of the nonionic surfactant sorbitan monooleate (SPAN 80, manufactured by Sigma-Aldrich) with 240 ml of liquid paraffin solvent.

[0201] Next, the continuous phase solution and the dispersed phase solution were ultrasonically treated for 2 minutes to form a W / O emulsion.

[0202] Next, the above W / O emulsion was stirred at a stirring speed of 400 rpm at room temperature for 30 minutes, and then reacted at 90°C for 2 hours.

[0203] Next, when the reaction is finished and particles are formed, the temperature is lowered to room temperature, and the particles are washed first with ethanol and then secondarily with hexane / ethanol (volume ratio 1:1). The particles are then vacuum-dried using a rotary evaporator at 40 ℃ at a pressure of 180 mmHg to obtain final superabsorbent resin particles in the form of white powder.

[0205] Experimental Example 1: Image observation of superabsorbent resin particles

[0206] The external surface images of the superabsorbent resin particles prepared in the above examples and comparative examples were captured at a magnification of 1,000 to 35,000 using a FE-SEM (Field Emission Scanning Electron Microscope, Product Name: S-4800, Manufacturer: Hitachi). As a result, images of the superabsorbent resin particles prepared in Examples 1 to 4, Comparative Example 1, and Comparative Examples 3 to 5 were sequentially shown in FIGS. 1 to 8, excluding Comparative Example 2, in which no particles were formed.

[0208] Experimental Example 2: Measurement of Physical Properties of Superabsorbent Resin Particles

[0209] The particle size, particle sphericity, hygroscopic capacity, moisture response evaluation, optical transmittance, and moisture penetration depth of the superabsorbent resin particles prepared in the above examples and comparative examples were measured by the following method, and the results are shown in Table 1 below.

[0211] (1) Particle size measurement

[0212] The particle size was determined by drying the superabsorbent resin particles in a vacuum oven at room temperature, then taking images of the external surface of the superabsorbent resin particles at a magnification of 1,000 to 35,000 using an FE-SEM (Field Emission Scanning Electron Microscope, product name: S-4800, manufacturer: Hitachi), measuring the diameters of 50 particles from the captured images, and determining the average value.

[0214] (2) Particle Sphericity

[0215] The particle sphericity rate was measured by drying superabsorbent resin particles in a vacuum oven at room temperature, then taking images of the external surface of the superabsorbent resin particles at a magnification of 1,000 to 35,000 using an FE-SEM (Field Emission Scanning Electron Microscope, product name: S-4800, manufacturer: Hitachi), quantifying the relative sphericity based on a particle that is perfectly spherical, i.e., has a sphericity rate of 100%, for 50 particles in the captured images, and then calculating the average value thereof.

[0217] (3) Moisture absorption capacity

[0218] The hygroscopic capacity was measured using the tea bag method, which can reflect the pure fluid content contained within the superabsorbent polymer particles by removing fluid present outside or between the particles. 0.2 g (±0.001 g) of dried superabsorbent polymer particles were placed in a tea bag and swollen in a 0.9% saline solution for 30 minutes. Then, the water was removed for 3 minutes in a centrifuge set to 1600 rpm, and the weight was measured. A tea bag without superabsorbent polymer particles was also weighed in the same manner according to the above method, and the hygroscopic capacity of the superabsorbent polymer particles was calculated using the following formula.

[0219] Moisture absorption capacity (g / g) = (W t - (W w + W d )) / W d

[0220] W t : Weight of the tea bag containing superabsorbent resin particles after soaking in brine

[0221] W w : Weight of the empty tea bag after soaking in brine

[0222] W d : Weight of the superabsorbent resin particles used

[0223] As a result of the measurement, the moisture absorption capacity was evaluated as 'High' if it was 30 g / g or higher, 'Medium' if it was 10 g / g or higher and less than 30 g / g, and 'Low' if it was less than 10 g / g.

[0225] (4) Moisture response evaluation (initial moisture absorption rate evaluation)

[0226] For the moisture response evaluation, 1 g of dried superabsorbent resin particles was placed in a 50 mL beaker and exposed to a chamber at 85°C and 100% relative humidity for about 5 hours. The initial absorption rate was calculated by measuring the increase in weight relative to the initial weight. Based on the measurement results, the initial absorption rate was evaluated as 'High' if it was 1 wt% / min or higher, 'Medium' if it was 0.8 wt% / min or higher but less than 1 wt% / min, and 'Low' if it was less than 0.8 wt%.

[0228] (5) Solvent dispersibility

[0229] Solvent dispersibility was evaluated by dispersing 0.5 g of dried superabsorbent resin particles in 10 mL of n-hexane solvent and observing changes in size by measuring the size of the superabsorbent resin particles at 1-minute intervals for a total of 10 minutes using a DLS (Dynamic light scattering, product name: NanoBrook 173Plus, manufacturer: Brookhaven) instrument. As a result of the measurement, the results were evaluated as 'High' if clumping of the superabsorbent resin particles occurred between 5 and 10 minutes, 'Medium' if clumping occurred between 1 and 5 minutes, and 'Low' if clumping occurred within 1 minute.

[0231] (6) Measurement and evaluation of moisture penetration depth

[0232] First, 60 parts by weight of polyisobutylene (Mw 200), 14 parts by weight of UV-reactive oligomer CN9014 (Evonik), 10 parts by weight of UV-reactive monomer isobornylacrylate (IBOA), and thixotropic agent silica AEROSIL ®A high-viscosity liquid composition was prepared by mixing 10 parts by weight of R812 (Evonik) and 0.5 parts by weight of the curing agent Irgacure 819 with 5.5 parts by weight of the superabsorbent resin particles prepared in the above examples, comparative examples, and reference examples.

[0233] Afterwards, two indicator films (films in which the degree of moisture penetration can be visually distinguished) with a size of 10*30 mm were attached to NEG glass (0.7T, 40*70 mm) at a distance of 10 mm.

[0234] Afterwards, a high-viscosity liquid composition prepared was thinly applied to the space between the two indicator films.

[0235] Afterwards, Invar metal (40*70 mm) was laminated (heated at 60°C, gap 1 mm) and attached to the NEG glass coated with the above high-viscosity liquid composition and indicator film.

[0236] Afterwards, the sample was placed in a constant temperature and humidity chamber (60℃, 90% relative humidity) and the change in moisture penetration length was checked after 250 hours, 500 hours, and 1000 hours, respectively.

[0237] However, due to the characteristics of the transparent high-viscosity liquid composition, it is difficult to visually confirm the water penetration length; therefore, the water penetration length was measured relatively using the degree of transparency of the indicator film as a measure.

[0238] The measurement results were evaluated as 'High' if there was moisture permeability performance compared to a blank ref. that does not contain superabsorbent resin particles, 'Medium' if there was no difference, and 'Low' if the moisture penetration length increased compared to a blank ref.

[0240] Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Dispersed commercial solution composition Total volume of dispersed acid solution 1) (mL) 19.2 19.6 17.12 16.92 15 16.92 16.92 16.92 8.72 PAA content 2) (% w / v) 5.7 5.6 6.4 6.4 - 6.4 6.4 6.4 12.5 crosslinking agent BDDE BDDE BDDE BDDE MBA BDDE BDDE BDDE BDDE Crosslinking agent content 3) (Weight portion) 323 323 32.3 32.3 - 32.3 32.3 32.3 32.3 Junghwado 4 ) (%) 0 33 66 50 70 50 50 50 33 Continuous commercial solution composition Continuous commercial solvent IPM IPM IPM IPM Liquid paraffin Liquid paraffin IPM IPM IPM Total volume of continuous solution 5) (mL) 320 320 320 320 340 320 240 240 240 Surfactant content 6) (% w / v) 5.25 5.25 2.5 2.5 2.94 2.5 3.33 0.54 3.33 w / o volume ratio 7) 1 / 16.67 1 / 16.33 1 / 18.69 1 / 18.91 1 / 22.67 1 / 18.91 1 / 14.18 1 / 14.18 1 / 27.52 Particle shape Particle size (㎛) 1.12± 0.70 0.42± 0.25 0.44± 0.17 0.80± 0.30 3.01± 0.98 particle formation 0.29± 0.10 0.33± 0.13 10.6± 5.98 Particle Sphericity Rate (%) 80 85 90 90 0 particle formation 10 0 0 Particle properties Moisture absorption capacity (g / g) middle middle award award under - - - middle Moisture Response Assessment (wt% / min) award award award award under - middle middle under Solvent dispersibility award award award award - - middle middle middle Moisture penetration depth - - - award under - - - -

[0241] 1) Total volume of dispersed phase solution (mL) = Content of polyacrylic acid composition + Content of neutralizing agent + Content of DI Water + Content of crosslinking agent

[0242] 2) PAA content (% w / v) = [(PAA content in 4 mL of 25 wt% PAA solution 1.09 g) / (Total volume of dispersed phase solution (mL)] * 100

[0243] 3) Crosslinking agent content (parts by weight) = Parts by weight of crosslinking agent relative to 100 parts by weight of PAA

[0244] 4) Degree of Neutralization (%) = [ (Moles of NaOH) / (Moles of repeating AA units per PAA) ] * 100

[0245] (Moles of AA repeating units per PAA (mol) = Amount of PAA added (g) / Molecular weight of AA repeating units (g / mol))

[0246] 5) Total volume of continuous phase solution (mL) = Content of continuous phase solvent

[0247] 6) Surfactant content (% w / v) = [ (Surfactant content (g) / (Total volume of continuous phase solution (mL) ] * 100

[0248] 7) w / o volume ratio = Volume of dispersed phase solution 1 / Reference / Volume of continuous phase solution

[0250] As can be seen in Table 1 above, the superabsorbent resin particles prepared in the above examples exhibit a spherical shape and significantly superior moisture absorption capacity, initial absorption rate, and moisture permeability performance compared to the superabsorbent resin particles of Comparative Example 1 prepared from acrylic acid monomers. On the other hand, it is confirmed that in the case of Comparative Example 2, which did not use an isoparaffin-based hydrocarbon solvent, superabsorbent resin particles were not formed.

[0252] In addition, it can be seen that the superabsorbent resin particles prepared in the above examples have a higher moisture absorption capacity and an excellent initial moisture absorption rate compared to the superabsorbent resin particles prepared in w / o emulsions where the volume ratio of the continuous phase solution to the dispersed phase solution is less than 15 or greater than 25 when preparing the superabsorbent resin particles, as well as excellent dispersibility in solvents and a spherical shape.

[0254] Thus, it was confirmed that it is possible to manufacture spherical nano-sized superabsorbent resin particles with excellent moisture absorption capacity, initial absorption rate, moisture resistance, and solvent dispersibility by using polyacrylic acid without a monomer polymerization process, using an isoparaffin-based hydrocarbon solvent as the continuous phase solvent, and crosslinking the polyacrylic acid within a droplet of a W / O emulsion (water-in-oil emulsion) in which the dispersed phase solution and the continuous phase solution satisfy a specific volume ratio.

Claims

Claim 1 A method for manufacturing superabsorbent resin particles, comprising: a first step of preparing a polyacrylic acid composition by mixing polyacrylic acid with an aqueous solvent; a second step of preparing a dispersed phase solution by mixing a polyvalent epoxy-based crosslinking agent with the polyacrylic acid composition; a third step of preparing a water-in-oil emulsion (W / O emulsion) by mixing a continuous phase solution containing a nonionic surfactant and an isoparaffin-based hydrocarbon solvent with the dispersed phase solution; and a fourth step of preparing superabsorbent resin particles by carrying out a crosslinking reaction within a droplet of the W / O emulsion; wherein the dispersed phase solution and the continuous phase solution are used in a volume ratio of 1:15 to 1:

25. Claim 2 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the polyacrylic acid has a weight-average molecular weight of 100,000 to 300,000 g / mol. Claim 3 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the polyacrylic acid and a basic solution are introduced together, so that at least some of the acidic groups of the polyacrylic acid in the polyacrylic acid composition are neutralized. Claim 4 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the polyvalent epoxy crosslinking agent is one or more diepoxy compounds selected from the group consisting of 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl diglycidyl ether, resorcinol diglycidyl ether, diethylene glycol diglycidyl ether, and ethylene glycol diglycidyl ether. Claim 5 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the polyacrylic acid is used in an amount of 1 to 10% w / v based on the total volume of the dispersed phase solution. Claim 6 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the polyvalent epoxy-based crosslinking agent is used in an amount of 10 to 500 parts by weight per 100 parts by weight of the polyacrylic acid. Claim 7 A method for manufacturing superabsorbent resin particles, wherein the nonionic surfactant has an HLB (Hydrophile-Lipophile Balance) value of 1 to 7 in claim 1. Claim 8 A method for manufacturing superabsorbent resin particles, wherein, in claim 1, the nonionic surfactant is a sorbitan fatty acid ester-based compound. Claim 9 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the nonionic surfactant is used in an amount of 1 to 10% w / v based on the total volume of the continuous phase solution. Claim 10 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the isoparaffinic hydrocarbon solvent has a viscosity of 1 to 10 mPa·s at 25°C. Claim 11 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the crosslinking reaction in the fourth step is performed by stirring at 300 to 1000 rpm. Claim 12 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the crosslinking reaction in the fourth step is performed at a temperature of 20 to 100 ℃ for 2 to 72 hours. Claim 13 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the superabsorbent resin particles have a particle size of 3 μm or less. Claim 14 A method for manufacturing superabsorbent resin particles according to claim 1, wherein the superabsorbent resin particles have a sphericity rate of 70% or more. Claim 15 A method for manufacturing superabsorbent resin particles according to claim 1, further comprising, after the fourth step, a step of recovering the superabsorbent resin particles from the W / O emulsion; a step of washing the recovered superabsorbent resin particles; and a step of drying the washed superabsorbent resin particles. Claim 16 A packaging material composition comprising: superabsorbent resin particles manufactured according to the manufacturing method of any one of claims 1 to 15; and a resin component.

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