WO2017111295A1 - Superabsorbent polymer and preparation method therefor - Google Patents

Abstract

The present invention relates to a superabsorbent polymer having an improved absorption rate and a high apparent density, and a preparation method therefor.

Description

 【Specification】

 [Name of invention]

 Super Absorbent Resin and Method for Making the Same

 Technical Field

Cross Citation with Related Application (s)

 This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0184614 dated December 23, 2015 and Korean Patent Application No. 10-2016-0144603 dated November 1, 2016, and the Korean patent application All content disclosed in these documents is included as part of this specification.

 The present invention relates to a super absorbent polymer and a method for producing the same. More particularly, the present invention relates to a super absorbent polymer having an improved absorption rate and high gallon density, and a method for preparing the same.

 [Technique to become background of invention]

 A super absorbent polymer (SAP) is a synthetic polymer material that can absorb about 500 to 1000 times its own weight. It is a super absorbent material (SAM), absorbent gel mater (ALM), etc. Also called. Super absorbent resins have been put into practical use as sanitary devices, and are now widely used in various materials such as hygiene products such as paper diapers for children, horticultural soil repair agents, civil engineering index materials, seedling sheets, and freshness retainers in food distribution. It is used.

 As a method for producing such a super absorbent polymer, a method by reverse phase suspension polymerization or a solution polymerization is known. Among them, the production of superabsorbent polymers through reverse phase suspension polymerization is disclosed, for example, in Japanese Patent Laid-Open Nos. 56-161408, 57-158209, and 57-198714. In addition, the production of superabsorbent polymers through polymerization of aqueous solution is a thermal polymerization method in which a hydrogel polymer is broken and immersed in a half-die with multiple axes, and is polymerized by irradiating ultraviolet light to a high concentration of aqueous solution on a belt. The photopolymerization method etc. which perform simultaneously and drying are known.

On the other hand, the rate of absorption, which is one of the important physical properties of superabsorbent polymers, is related to the surface dryness of products that touch the skin, such as diapers. Generally this One absorption rate can be improved by increasing the surface area of the superabsorbent polymer.

 For example, a method of forming a porous structure on the particle surface of the super absorbent polymer by using a blowing agent has been applied. However, there is a disadvantage in that the general foaming agent cannot form a porous structure of each layer, so that the increase in absorption rate is not large.

 As another example, there is a method of increasing the surface area by reassembling the fine powder obtained in the manufacturing process of the super absorbent polymer to form porous particles of irregular shape. However, although the absorption rate of the superabsorbent polymer can be improved through this method, there is a limit that the water retention capacity (CRC) and the pressure absorption capacity (AUP) of the resin are relatively lowered. As such, physical properties such as absorption rate, water holding capacity, and pressure absorbing capacity of the super absorbent polymer are trade-off (t rade of f). Therefore, there is an urgent need for a manufacturing method capable of improving these properties simultaneously.

 Prior Art Documents

 [Patent literature]

 (Patent Document 1) 1. Japanese Patent Laid-Open No. 56-161408

(Patent Document 2) 2. Japanese Patent Laid-Open No. 57-158209

(Patent Document 3) 3. Japanese Patent Laid-Open No. 57-198714

 [Content of invention]

 Problem to be solved

 The present invention is to provide a super absorbent polymer having improved absorption rate and high apparent density.

 In addition, the present invention is to provide a method for producing the super absorbent polymer.

 [Measures of problem]

In this specification, the base resin powder containing the crosslinked polymer of the water-soluble ethylene-type unsaturated monomer which has the acidic group neutralized at least one part, The base resin powder has the several hole of diameter 1fi or more formed, The said crosslinked polymer The super absorbent polymer contains layered silicate particles dispersed in the crosslinked structure, and has a squeezed density of at least 0.5 g / mt. Ball.

 The present specification also includes a base resin powder containing a cross-linked polymer of a water-soluble ethylenically unsaturated monomer having at least a portion of neutralized acidic groups, and a plurality of pores of diameter 1 / m or more are formed in the base resin powder, A superabsorbent polymer having a density of 0.55 g / m £ or more and a time for removing vortex generated when stirring 0.9 wt% NaCl solution 50 at 600 rpm at a speed of 54 seconds or less is provided.

 In the present specification, a water-containing gel polymer is obtained by crosslinking and polymerizing a monomer composition comprising a layered silicate-based particle, a foaming agent, an internal crosslinking agent, and a water-soluble ethylene-based unsaturated monomer having at least part of a neutralized acidic group, and stirred at a speed of 1000 rpm or more. Forming a; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, wherein the concentration of the water-soluble ethylenically unsaturated monomer included in the monomer composition is 40% by weight to 60% by weight of the superabsorbent polymer. A manufacturing method is provided.

In the present specification, the water-containing gel polymer is further crosslinked with a monomer composition comprising a layered silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least a portion of an acidic group, and stirred at a speed of 1000 rpm or more. Forming; And drying, pulverizing, and classifying the hydrogel polymer to form a base water powder, and drying, pulverizing, and classifying the hydrogel polymer to form a base resin powder includes: particle diameter of the hydrogel polymer The coarsely crushing step is pulverized so as to be 2 kPa to 10 kPa, wherein the coarsely crushing step is provided ^{at a} temperature of 50 ^° C. or more, and a method for producing a super absorbent polymer which proceeds at a frequency of 15 Hz or more.

In the present specification, the hydrogel polymer is further crosslinked with a monomer composition comprising a layered silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least part of a neutralized acidic group, and stirred at a speed of 1000 rpm or more. Forming; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, and drying, pulverizing and classifying the hydrogel polymer to form a base resin powder. Coarse grinding step of grinding so that the particle size becomes 2 隱 to 10 腿 It includes, and before or after the coarse grinding step, with respect to 100 parts by weight of the hydrogel polymer, there is provided a method for producing a super absorbent polymer further comprising the step of adding water in an amount of less than 20 parts by weight.

Hereinafter, a super absorbent polymer according to a specific embodiment of the present invention, and a preparation method thereof will be described in detail. Unless specifically stated throughout this specification, "comprising" or "containing" refers to including any component (or component) without particular limitation, and excluding the addition of other components (or components). Cannot be interpreted as. In the present specification, (meth) acryl [(meth) acryl] is meant to include both acryl and methacryl. Follow with one embodiment of the ^invention, if, in the number of soluble including a base resin powder, including cross-linked polymers of ethylenically unsaturated monomers, and the base resin powder having an at least partially neutralized acid has a plurality of pores over a diameter of 1 formation The crosslinked polymer is crosslinked _. A superabsorbent polymer containing layered silicate particles dispersed in the structure and having an apparent density of 0.55 g / val or more can be provided.

 The inventors of the present invention use the above-described superabsorbent polymer, and by using specific layered silicate-based particles, a plurality of micropores can be stably formed in the crosslinked polymer, and the contact area with water increases rapidly. The absorption rate of the absorbent resin can be further improved, and the experiment was confirmed that the superabsorbent polymer having a high apparent density can be prepared through experiments and completed the invention.

Specifically, the super absorbent polymer may include a base resin powder including a cross-linked polymer of a water-soluble ethylenically unsaturated monomer having at least a portion of the acid group. The "crosslinked polymer of water-soluble ethylenically unsaturated monomer" is a hydrogel polymer immediately formed by thermal polymerization or photopolymerization to a composition containing a water-soluble ethylenically unsaturated monomer, as well as a general method for producing a super absorbent polymer. A polymer obtained by drying the hydrogel polymer, a polymer obtained by grinding the hydrogel polymer or dried polymer, surface crosslinking It includes both the polymer before the reaction or the polymer after the surface crosslinking reaction, and if the water-soluble ethylenically unsaturated monomer is a polymerized polymerizer, all polymers are included regardless of the form, water content, particle size, surface crosslinking or the like. Can be.

 The super absorbent polymer of the above embodiment basically includes a polymer obtained by crosslinking polymerization of the water-soluble ethylenically unsaturated monomer as a base resin powder, as in the previous super absorbent polymer.

 In the super absorbent polymer of one embodiment, the water-soluble ethylene-based unsaturated monomer, acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacrylo Anionic monomers of monoethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, or 2- (meth) acrylamide-2-methyl propane sulfonic acid and salts thereof; (Meth) acrylamide, N-substituted (meth) acrylates, 2-hydroxyethyl (meth) acrylates, 2-hydroxypropyl (meth) acrylates, hydroxypolyethylene glycol (meth) acrylates or polyethylene Nonionic hydrophilic-containing monomers of glycol (meth) acrylates; And amino group-containing unsaturated monomers of (Ν, Ν) -dimethylaminoethyl (meth) acrylate or (Ν, Ν) -dimethylaminopropyl (meth) acrylamide and quaternized products thereof; 1 selected from the group consisting of More than one species can be used. In addition, alkali metal salts such as acrylic acid or salts thereof, for example acrylic acid and / or sodium salts thereof, to which at least a portion of acrylic acid has been amplified, may be used, and such monomers may be used for superabsorbent polymers having superior physical properties. Manufacturing becomes possible. When the alkali metal salt of acrylic acid is used as a monomer, acrylic acid can be neutralized with a basic compound such as caustic soda (NaOH).

In addition, the crosslinked polymer included in the base resin powder may include a crosslinked structure in which polymer chains of the water-soluble ethylenically unsaturated monomer are crosslinked through a crosslinkable functional group of an internal crosslinking agent. As the internal crosslinking agent for introducing the basic crosslinking structure into the crosslinked polymer and the base resin powder, any internal crosslinking agent having a crosslinkable functional group, which has conventionally been used in the manufacture of superabsorbent polymers, can be used without any particular limitation. However, by introducing an appropriate crosslinked structure into the crosslinked polymer and the base resin powder, physical properties of the superabsorbent polymer In order to further improve the polyfunctional acrylate compound having a plurality of ethylene oxide groups can be used as the internal crosslinking agent. More specific examples of such internal crosslinking agents include polyethylene glycol diacrylate (PEGDA), glycerin diacrylate, glycerin triacrylate, unmodified or ethoxylated trimethyl triacrylate (TMPTA), nucleic acid diol diacrylate, And triethylene glycol diacrylate. On the other hand, the base resin powder may have a plurality of pores of 1 or more in diameter, or 1 to 10 kPa, or 1 kPa to 1000 mi. The pores are implemented by a blowing agent added together in the monomer composition, as shown in the method of preparing a superabsorbent polymer, which will be described later. As shown in FIG. 2, a plurality of pores having a minimum diameter of 1 or more are formed on the base powder. You can see that it is formed. The pores may be present in a plurality of forms, evenly dispersed in the base resin powder.

 In particular, among the plurality of pores of diameter 1 m or more contained in the base resin powder may include micropores having a diameter of 10 to 100 urn. The micropores having a diameter of 10 to 100 μη may be formed by adding a blowing agent and inorganic particles together when forming a polymer, as described below. As such micropores are stably formed, the microporosity is increased. The absorption rate of the water absorbent resin can be further improved.

 In addition, the crosslinked polymer contained in the base resin powder may include layered silicate particles dispersed in the crosslinked structure. As the layered silicate-based particles, particles including a metal oxide layer including a metal oxide and unit crystals formed on at least one surface of the metal oxide layer and including a silica layer including silica may be used.

 The unit crystal refers to a periodic unit of crystalline particles having three-dimensional periodicity, and particles may be formed through repetition of the unit crystal.

The unit crystal of the layered silicatetic bib may be formed on at least one surface of the metal oxide layer including the metal oxide and the metal oxide layer, and may include a silica layer including silica. That is, the silica layer is formed on one side or both sides of the metal oxide layer in the unit crystal of the layered silicate particles. Can be.

 Specifically, the metal oxide layer and the silica layer may be bonded through a siloxane bond. The siloxane bond means a covalent bond between a silicon atom (Si) and an oxygen atom (0), and more specifically, an oxygen atom included in the metal oxide layer, such as a unit crystal structure shown in FIG. 1. A bond between the metal oxide and the silica layer may be formed through a covalent bond between and silicon atoms included in the silica layer.

 In the metal oxide layer, the metal oxide may exist in a state in which a metal atom and an oxygen atom are bonded to each other, and examples of the metal atom are not particularly limited, and lithium, sodium, potassium, and the like are group 1 or group 2 elements of the periodic table. Beryllium, magnes, and sword.

 Accordingly, the layered silicate-based particles can stably maintain fine pores in the crosslinked polymer and increase the contact area with water to further improve the absorption rate of the super absorbent polymer.

 The layered silicate particles may have a light structure having a maximum diameter of 1 ran to 100 ran and a height of O.Olnm to 20 nm, or O.lnm to 20 nm. The lamp structure means a three-dimensional figure in which the upper and lower surfaces are parallel to each other. Although the specific shape of the light emitting structure is not limited, for example, according to the type of cross section in which the layered silicate particles are cut in a direction parallel to the ground, that is, a cylinder, an ellipse, etc. Etc. can be mentioned.

 As described above, the light emitting structure of the layered silicate particles may be formed by repetition of the unit crystal, and the maximum diameter of the straight section in the columnar structure is a cross section of the layered silicate particles cut in a direction parallel to the ground. It means the largest value among the diameters it can have.

As such, the layered silicate particles have a light structure having a maximum diameter of 1 nm to 100 nm and a height of 0.1 nm to 20 nm of the straight section, so that the layered silicate particles in the crosslinked polymer of the embodiment are fine. One particle size not only enables functionality in the crosslinked polymer, but is also formed by the blowing agent in the monomer composition when the crosslinked polymer is formed. It can stabilize the micropores that are.

 Examples of the layered silicate-based particles are not particularly limited, and examples thereof include hackite (Laponite RD, Laponite XLG, Laponite D, Laponite DF Laponite RS, Laponite XLS, Laponite DS, Laponite S and Laponite JS, etc.). And a more preferred example is Laponite RD.

 In addition, the layered silicate-based particles described above may be included in an amount of 0.01 parts by weight to 30 parts by weight, or 0.01 parts by weight to 5 parts by weight, or 0. 2 parts by weight to 0.1 parts by weight based on 100 parts by weight of the base resin powder. . As a result, the degree of formation of fine pores in the crosslinked polymer is optimized, so that the highly absorbent resin of one embodiment may have an improved absorption rate.

Specifically, the super absorbent polymer of the embodiment has an apparent density (Bulk Density, B / D) of 0.55.

Or 0.55 g / mi to 1.0 g / mi, or 0.55 g / mi to 0/70 g / al. When the dimple density of the super absorbent polymer is excessively reduced to less than 0.55 g / mt, the volume of the superabsorbent polymer is relatively high; Increasingly, more storage space is needed, which can reduce storage efficiency. In addition, when the superabsorbent polymer is applied to a manufacturing process such as a diaper, the superabsorbent polymer particles may be stagnant without being smoothly introduced, thereby reducing the efficiency of the process.

 In addition, the super absorbent polymer of the embodiment may have a time for removing the vortex generated when stirring 0.9 wt% NaCl solution 50 at 600 rpm, 60 seconds or less, or 40 seconds to 60 seconds.

 In addition, the superabsorbent polymer may have a water holding capacity of 40 g / g or more, or 40 g / g to 60 g / g of physiological saline measured according to the EDANA WSP 241.2 method. Centrifuge water capacity (CRC) for physiological saline can be measured according to the method of EDANA method WSP 241.2. More specifically, the water retention capacity may be calculated by Equation 1 below after absorbing the superabsorbent polymer in physiological saline over 30 minutes.

 [Calculation 1]

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

In the above formula 1, W ₀ (g) is the initial weight (g) of the superabsorbent polymer, W g) is the weight of the device measured after dehydration at 250G for 3 minutes using a centrifuge without using the superabsorbent polymer, W ₂ ( g) is the weight of the device, including the superabsorbent polymer, after submerging the superabsorbent polymer in physiological saline of 0.9 wt.% at room temperature for 30 minutes and then dehydrating it at 250 G for 3 minutes using a centrifuge.

 In addition, the super absorbent polymer of the above-described embodiment may have a particle shape such as spherical or amorphous having a particle diameter of about 850 ΛΠ.

 On the other hand, according to another embodiment of the invention, at least a part comprises a base resin powder containing a cross-linked polymer of a water-soluble ethylenically unsaturated monomer having a neutralized acid group, a plurality of pores of diameter 1 or more is formed in the malleable base resin powder And a superabsorbent polymer having an apparent density of at least 55 g / m £ and removing a vortex generated when stirring 0.9 wt% of NaCl solution 50 at 600 rpm at a speed of 600 rpm can be provided.

Content included in the other embodiment may include all the above-described information in the embodiment. On the other hand, according to another embodiment of the invention, the monomer composition comprising a layered silicate-based particles, foaming agent, internal crosslinking agent and a water-soluble ethylenically unsaturated monomer having at least a part of the neutralized acid group, stirred at a rate of 1000 rpra or more Crosslinking polymerization to form a hydrogel polymer; And the function of drying, pulverizing, and classifying a gel of the polymer, including the steps of forming a base resin powder, wherein the monomer ^composition, the concentration of the water-soluble ethylenic unsaturated monomer contained in the water 40 wt% to 60 wt%, and A method for producing a water absorbent resin can be provided. In addition, cross-linking polymerization of the monomer composition comprising a water-soluble ethylenically unsaturated monomer having a layered silicate-based particles, a blowing agent, an internal magnetic crosslinking agent and at least a part of the neutralized acid group, and stirred at a speed of 1000 rpm or more to form a hydrogel polymer ; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, and drying, pulverizing and classifying the hydrogel polymer to form a base resin powder. Coarse grinding step of grinding to a particle diameter of 2mm to 10 誦, the The coarsely pulverizing step may be provided with a method for producing a super absorbent polymer, which proceeds at a frequency of 15 Hz or higher at a temperature of 50 ^° C. or higher.

 In addition, cross-polymerizing a monomer—composition comprising a water-soluble ethylenically unsaturated monomer having a layered silicate-based particles, a blowing agent, an internal crosslinking agent and at least a part of a neutralized acidic group, and stirred at a speed of at least 1000 rpm to form a hydrogel polymer. ; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, and drying, pulverizing and classifying the hydrogel polymer to form a base resin powder. A coarse grinding step of pulverizing to a particle diameter of 2 to 10 隱, and before or after the coarse crushing step, adding water to a content of less than 20 parts by weight with respect to 100 parts by weight of the hydrogel polymer It can be provided a method for producing a super absorbent polymer further comprising.

 In this method of producing another embodiment, the layered silicate particles are used together with a conventional blowing agent and an internal crosslinking agent to proceed with the crosslinking polymerization of the water-soluble ethylenically unsaturated monomer, followed by drying according to a general method for preparing a super absorbent polymer. The superabsorbent polymer can be prepared by pulverizing, classifying and surface crosslinking. As such, in the crosslinking polymerization step of the water-soluble ethylenically unsaturated monomer, as the layered silicate particles and the blowing agent are used together, fine bubbles generated by the blowing agent can be stably maintained by the layered silicate particles. The absorption rate of the superabsorbent polymer to be prepared can be improved more, and the base resin powder having the crosslinked structure already formed by the use of an internal crosslinking agent can be prepared, thereby realizing various physical properties such as excellent water retention.

In particular, the superabsorbent polymer production method of another embodiment includes a monomer composition comprising a layered silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least a part of which is neutralized acid group, at least 1000 rpm, or 1000 By stirring at a speed of rpm to 20000 rpm, or 1000 rpm to 10000 rpm, or 5000 rpm to 7000 rpm, a high shear force can be applied to the monomer composition, so that the base resin powder has a size of several mm to several tens of microseconds. It can suppress the formation of macropores as much as possible, and the diameter is 10 It is possible to distribute a large number of microporous to 100 to 100 IM.

In addition, the monomer composition is stirred at a speed of 1000 rpm or more, and then 1) the concentration of the water-soluble ethylenically unsaturated monomer contained in the monomer composition is adjusted to 40% by weight to 60% by weight, or 2) the coarse grinding step is 50 ^° At a temperature above C, at a frequency of 15 Hz or higher, or 3) by adding water in an amount of less than 20 parts by weight, relative to 100 parts by weight of the hydrogel polymer before or after the coarse grinding step, By reducing the nonuniformity of the particle shape, it is possible to increase the apparent density of the high absorbent resin.

 Specifically, the method of preparing the super absorbent polymer includes a layered silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least a portion of neutralized acidic groups, and a monomer composition stirred at a speed of 1000 rpm or more. Cross-linking polymerization to form a hydrogel polymer. 、

 Examples of the method for preparing the monomer composition are not particularly limited, and for example, the layered silicate-based particles, the blowing agent, the internal crosslinking agent, and at least a portion of the water-soluble ethylenically unsaturated monomer having an acidic group neutralized at the same time or sequentially. Examples thereof include a method of mixing with a solvent or the like. More specifically, a first mixture of a water-soluble ethylenically unsaturated monomer and an internal crosslinking agent is prepared, a second mixture of layered silicate particles and a blowing agent is prepared, and then the first mixture and the second mixture are prepared. For example, a method of mixing the same may be mentioned.

 The monomer composition may be stirred at a speed of 1000 rpm or more, or 1000 rpm to 20000 rpm, or 3000 rpm to 10000 rpm. Thus, through high-speed stirring, high shear force can be applied to the monomer composition, it is possible to suppress the formation of macropores of several mm to several tens of millimeters in the size of the base resin powder to the maximum, fine diameter of 10 to loo Multiple pores can be distributed.

More specifically, an example of a method of stirring the monomer composition is not particularly limited, and for example, a method of passing the monomer composition through a high shear force stirring device (dynami c mechani cal system, DMS) may be mentioned. The high shear agitation device (dynami c mechani cal system, DMS) is a pump and Including a stirrer, the motor speed of the pump is 0 to 6000 rpm, the speed of the stirring may be 0 to 20000 rpm.

 As the layered silicate particles, particles including a metal oxide layer containing a metal oxide and a unit crystal formed on at least one surface of the metal oxide layer and including a silica layer containing silica may be used.

 The unit crystal refers to a periodic unit of crystalline particles having three-dimensional periodicity, and particles may be formed through repetition of the unit crystal.

 The unit crystal of the layered silicate-based particles may be formed on at least one surface of the metal oxide layer including the metal oxide and the metal oxide layer, and may include a silica layer including silica. That is, the silica layer may be formed on one side or both sides of the metal oxide layer in the unit crystal of the layered silicate particles.

 Specifically, the metal oxide layer and the silica layer may be bonded through a siloxane bond (s i loxane). The siloxane (si loxane) bond means a covalent bond between a silicon atom (Si) and an oxygen atom (0), and more specifically, the oxygen included in the metal oxide layer, as shown in the unit crystal structure shown in FIG. A bond between the metal oxide and the silica layer may be formed through a covalent bond between atoms and silicon atoms included in the silica layer. .

 In the metal oxide layer, the metal oxide may be present in a state in which a metal atom and an oxygen atom are bonded to each other, and examples of the metal atom are not particularly limited, and lithium, sodium, potassium, Beryllium, magnesium, calcium and the like.

 The layered silicate-based particles have a maximum diameter of 1 ran to 100 nm in a straight section, and a height of 0. Olnm to 20 ran, or O. It may have a light structure of 1 nm to 20 nm. The lamp structure means a three-dimensional figure in which the upper and lower surfaces are parallel to each other. Although the specific shape of the light emitting structure is not limited, for example, according to the type of cross section in which the layered silicate particles are cut in a direction parallel to the ground, that is, a primitive lamp, an ellipse group, etc. Etc. may be mentioned.

As described above, the light structure of the layered silicate particles is It can be formed through the repetition of the unit crystal, the maximum diameter of the straight cross-section in the lamp structure means the largest value among the diameter that the cross section cut the layered silicate particles in a direction parallel to the ground.

 As such, the layered silicate-based particles have a maximum diameter of 1 nm to 100 nm in a straight section, and a height of 0. As having a light structure of Olnm to 20 GPa, the layered silicate particles in the crosslinked polymer of the embodiment can not only realize functionality in the crosslinked polymer through a fine indenter size, but also when forming the crosslinked polymer. It is possible to stabilize the micropores formed by the blowing agent in the monomer composition.

 Examples of the layered silicate-based particles are not particularly limited, for example, nuclear lite (Laponi te RD, Laponi te XLG, Laponi te D, Laponi te DF Laponi te RS, Laponi te XLS, Laponite DS, Laponi te S and Laponi te JS and the like), and Laponi te RD is more preferable.

 Examples of the blowing agent are not particularly limited, and various blowing agents well known in the art may be used without limitation. Specifically, for example, azodi carbonamide, azodicarboxyamide, benzenesulfonylhydrazide, dinitrosopenta methylenetetramine, toluenesulfonylhydrazide, azobisisobutyronitrile, azo dicarboxylic acid And at least one selected from the group consisting of barium and sodium bicarbonate.

 As described above, the step of cross-polymerizing the water-soluble ethylenically unsaturated monomer having at least a part of the neutralized acidic group to form a hydrogel polymer may be carried out in the presence of layered silicate particles, blowing agent and internal crosslinking agent. That is, it may be to polymerize the monomer composition including the layered silicate-based particles, the blowing agent, the internal crosslinking agent, and the water-soluble ethylenically unsaturated monomer having at least one neutralized acidic group.

 As such, instead of forming the hydrogel polymer and then adding the layered silicate particles, the blowing agent, and the like, the fine pore even inside the hydrogel polymer is added by adding the layered silicate particles and the blowing agent to the monomer composition for forming the hydrogel polymer. Can be formed.

At this time, the layered silicate particles, foaming agent, internal crosslinking agent and at least The content of the layered silicate particles may be 1 part by weight to 50 parts by weight based on 100 parts by weight of the blowing agent in the monomer composition including a water-soluble ethylenically unsaturated monomer having a neutralized acidic group.

 When the content of the layered silicate particles is excessively reduced to less than 1 part by weight with respect to 100 parts by weight of the blowing agent, the pore stabilization effect by the layered silicate particles may be reduced to reduce the absorbency of the super absorbent polymer.

 As for the internal crosslinking agent, and the type and structure of the water-soluble ethylenically unsaturated monomer, and the like, as described above, additional yarn description thereof will be omitted.

 On the other hand, in the step of forming the hydrogel polymer, the concentration of the water-soluble ethylenically unsaturated monomer contained in the monomer composition may be 40% by weight to 60% by weight, or 40% by weight to 50% by weight. When the concentration of the monomer is excessively low, the yield of the superabsorbent polymer may be low and problems may occur. On the contrary, when the concentration is excessively high, some of the monomer may precipitate or the grinding efficiency of the polymerized hydrogel polymer may be low. Problems may occur in the process and the physical properties of the super absorbent polymer may be reduced.

 In addition, the monomer composition may further include a polymerization initiator generally used in the preparation of a super absorbent polymer.

 Specifically, the polymerization initiator may use 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 of ultraviolet rays or the like, and a certain amount of heat is generated in accordance with the progress of the ^ reaction reaction, which is an exothermic reaction, an additional thermal polymerization initiator may be included. It may be.

 The photopolymerization initiator may be used without any limitation as long as it is a compound capable of forming radicals by light such as ultraviolet rays.

Examples of the photopolymerization initiators include benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketal. Ketal), acyl phosphine and alpha-aminoketone One or more selected from the group consisting of (α-aminoketone) can be used. Meanwhile, as an example of acylphosphine, commercially available lucirin TP0, that is, 2,4, 6-trimethyl-benzoyl-trimethyl phosphine ^' oxide (2,4,6—trimethyl-benzoyl-trimethyl phosphine oxide) can be used. Can be. A wider variety of photoinitiators is well specified in Reinhold Schwalm lm "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007)" pll5, and is not limited to the examples described above.

 The photopolymerization initiator may be included in a concentration of about 0.01% by weight to about 1.0% by weight based on the monomer composition. When the concentration of the photopolymerization initiator is too low, the polymerization rate may be slow. When the concentration of the photopolymerization initiator is too high, the molecular weight of the superabsorbent polymer may be low and the physical properties may be uneven.

In addition, the thermal polymerization initiator may be used at least one selected from the group consisting of persulfate initiator, azo initiator, hydrogen peroxide and ascorbic acid. Specifically, examples of persulfate-based initiators include sodium persulfate (Na2S ₂ 0s), potassium persulfate (K2S208), ammonium persul fate (NH ₄ ) ₂ S ₂ 0 ₈ Examples of azo initiators include 2, 2-azobis- (2-amidinopropane) dihydrochloride (2, 2- azob is (2-am idi nopr opane) dihydrochlor ide), 2 ， 2-Azobis one (N, N_dimethylene) isobutyramidine. Dihydrochloride (2,2-azobis- (N, N-dimethylene) isobutyramidine dihydrochlor ide), 2— (carbamoyl azo) isobutyronitrile (2— (carbamoylazo) isobutylonitril), 2, 2-azobis [2 -(2-imidazolin-2-yl) propane] dihydrochloride (2, 2-azob is [2- (2-imi dazo 1 i n-2- yDpropane] dihydrochlor ide), 4,4—azobis (4—Cyanovaleric acid) (4, 4_ azobis- (4-cyanovaleric acid)), etc. For more various thermal polymerization initiators, see Odian, Principle of Polymer izat ion (Wi ley, 1981). , p203 is well specified, and is not limited to the example described above.

The thermal polymerization initiator may be included in a concentration of about 0.001% to about 0.5% by weight based on the monomer composition. When the concentration of such thermal polymerization initiator is too low, additional thermal polymerization hardly occurs, resulting in thermal polymerization. The effect of the addition of the reagent may be insignificant, and if the concentration of the thermal polymerization initiator is too high, the molecular weight of the superabsorbent polymer may be small and the physical properties may be uneven. In addition, the type of the internal crosslinking agent included in the monomer composition is already described above, and the internal crosslinking agent may crosslink the polymerized polymer. In particular, since such an internal crosslinking agent is used in an amount of about 0.03 parts by weight or more, and about 0.03 parts by weight to 0.6 parts by weight with respect to 100 parts by weight of the aforementioned monomer, for example, unneutralized acrylic acid, the above-described embodiment of the embodiment Superabsorbent resins that more adequately stratify physical properties can be produced.

 In addition, the monomer composition may further include additives such as an emulsifier, a thickener, a plasticizer, a storage stabilizer, an antioxidant, and the like, as necessary. Specific examples of the additives are not particularly limited, and various kinds of known additives may be used without limitation. However, examples of the emulsifiers include fatty acid esters including sugars, and more specifically, sucrose esters.

 Raw materials such as the above-mentioned water-soluble ethylene-based unsaturated monomers, silicate-based particles, photopolymerization initiators, thermal polymerization initiators, internal crosslinking agents, and additives may be prepared in the form of a monomer composition solution dissolved in a solvent.

 The solvent that can be used at this time can be used without limitation in the composition as long as it can dissolve the above-mentioned 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, cyclonucleanone, cyclopentanone, diethylene glycol monomethyl ether , Diethylene glycol etheryl ether, toluene, xylene, butyrolactone, carbye, may be used in combination of one or more selected from methyl cellosolve acetate and Ν, Ν-dimethylacetamide.

 The solvent may be included in the remaining amount except for the components described above with respect to the total content of the monomer composition.

On the other hand, a method of forming a hydrogel by thermal polymerization or photopolymerization of such a monomer composition is also a commonly used polymerization method, in particular There is no limit.

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

 For example, as described above, a water-containing gel polymer obtained by thermal polymerization by supplying hot air or by heating a reactor according to the shape of the stirring shaft provided in the reactor is a reactor, such as a kneader having a stirring shaft. The hydrogel polymer discharged to the outlet may be in the form of several centimeters to several millimeters. Specifically, the size of the resulting hydrogel polymer may vary depending on the concentration of the monomer composition to be injected, and the injection speed, etc., a hydrogel polymer having a weight average particle diameter of about 2 mm to 50 mm can be obtained.

 In addition, when the photopolymerization proceeds in a semi-unggi equipped with a movable conveyor belt as described above, the form of the hydrogel polymer generally obtained may be a hydrogel polymer on the sheet having a width of the belt. At this time, the thickness of the polymer sheet depends on the concentration and the injection speed of the monomer composition to be injected, but it is preferable to supply the monomer composition so that a polymer on a sheet having a thickness of usually about 0.5 cm to about 5 cm can be obtained. Do. When supplying the monomer composition to such an extent that the thickness of the polymer on the sheet is too thin, the production efficiency is not preferable because it is low, and when the polymer thickness on the sheet exceeds 5 cm, due to the excessively thick thickness, the polymerization reaction is carried over the entire thickness. It may not happen evenly.

In this case, the water content of the hydrogel polymer obtained by the above method may be 40% by weight to 80% by weight. On the other hand, "water content" as used throughout the present specification means the amount of water occupied with respect to the total weight of the hydrogel polymer, minus the weight of the polymer in the dry state. Specifically, it is defined as a value calculated by measuring the weight loss due to moisture evaporation in the polymer during the drying process of drying the temperature of the polymer through infrared heating. At this time, dry conditions are maintained at 180 ^° C after raising the temperature to about 180 ^° C at room temperature In this way, the total drying time is set to 20 minutes, including 5 minutes of temperature rise, and the moisture content is measured.

 And, after cross-polymerizing the monomer, it is possible to obtain a base resin powder through a process such as drying, grinding and classification, the base resin powder and a super absorbent water obtained therefrom through such a process such as grinding and classification Paper is suitably made and provided to have a particle diameter of about 150 to 850. More specifically, the base resin powder and. At least about 95% by weight or more of the superabsorbent polymer obtained therefrom has a particle diameter of about 150 rni to 850, about

The fine powder having a particle diameter of less than 150 may be less than about 3 weight ¾>.

 Thus, as the particle size distribution of the base resin powder and the super absorbent polymer is adjusted to a preferred range, the final manufactured super absorbent polymer may exhibit the above-described physical properties and better liquid permeability.

 On the other hand, it will be described in more detail with respect to the progress of the drying, grinding and classification as follows.

 First, in drying the hydrogel polymer, if necessary, the step of coarsely pulverizing before drying may be further increased to increase the efficiency of the drying step.

Specifically, the coarsely pulverizing step is ^at least 50 ^° C, or 50 ^° C to 150 ^° C, or 60 ^° C to 100 ^° C, at least 15 Hz, or 15 Hz to 40 Hz, or 15 Hz to 30 It can proceed at a frequency of Hz. The temperature of the grinding step may be a grinding device, a grinding blade, or a silver of an external heat source, and the frequency may be a vibration frequency of the grinding device or the grinding blade.

In addition, the superabsorbent polymer production method is less than 20 parts by weight, or 0 parts by weight to 19 parts by weight, or 10 parts by weight to 19 parts by weight based on 100 parts by weight of the hydrogel polymer before or after the coarse grinding step. It may further comprise the step of adding water in the amount of parts. In the step of adding water, water means ionized water, and when the content of water is 20 parts by weight or more based on 100 parts by weight of the crosslinked polymer, the physical properties of the superabsorbent polymer may be lowered, such as water retention. In addition, the apparent density of the superabsorbent polymer may be reduced, thereby reducing storage efficiency. At this time, the pulverizer used is not limited in configuration, specifically, a vertical pulverizer, a turbo cutter, a turbo grinder, a rotary cutter mill, a cutting machine Any one selected from the group of crushing machines consisting of a cutter mill, a disc mill, a shred crusher, a crusher, a chopper and a disc cutter It may include, but is not limited to the above examples.

At this time, the coarsely pulverizing step may be pulverized so that the particle size of the hydrogel polymer is about 2 隱 to about 10 隱. Grinding to a particle diameter of less than 2 GPa is technically not easy due to the high water content of the ^' hydrogel polymer ^' , and may also cause aggregation of the pulverized particles with each other. On the other hand, when the particle diameter is more than 10 mm, the effect of increasing the efficiency of the subsequent drying step may be insignificant.

As described above, drying is performed on the hydrogel polymer immediately after polymerization, which is coarsely pulverized or not subjected to the coarsely pulverized step. At this time, the drying temperature of the drying step may be about 150 ^° C to about 250 ^° C. If the drying temperature is less than about 150 ^° C, the drying time may be too long and the physical properties of the final superabsorbent polymer may be lowered. If the drying temperature exceeds about 250 ^° C, only the polymer surface may be excessively dried. Fine powder may be generated in a subsequent grinding step, and there is a fear that the physical properties of the superabsorbent polymer to be finally formed are reduced. Therefore, the preferred the drying can proceed at a temperature of about 150 ° C to about 200 ^° C.

 On the other hand, in the case of drying time, in consideration of the process efficiency, etc., it may proceed for about 20 minutes to about 90 minutes, but is not limited thereto.

 If the drying method of the drying step is also commonly used as a drying step of the hydrogel polymer, can be selected and used without limitation of the configuration. Specifically, the drying step may be performed by hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation. The water content of the polymer after such a drying step may be about 0.1% by weight to about 10% by weight.

The polymer powder obtained after the grinding step has a particle diameter of about 150 mi to about 850 // m can be The grinder used to grind to such a particle size is specifically a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill ) Or a jog mill may be used, but is not limited to the example described above.

 In addition, in order to manage the physical properties of the super absorbent polymer powder to be finalized after such a grinding step, a separate process of classifying the polymer powder obtained after grinding according to the particle size may be performed. Preferably, the polymer having a particle size of about 150 / im to about 850 / zm may be classified, and only a polymer powder having such a particle size may be further commercialized through a surface crosslinking reaction step or the like as necessary. Since the particle size distribution of the base resin powder obtained through such a process has already been described above, a detailed description thereof will be omitted.

On the other hand, the production method of the other embodiment comprises a layered silicate-based particles, a blowing agent, an internal crosslinking agent and at least a portion of the water-soluble ethylenically unsaturated monomer having a neutralized acid group, crosslinked polymerization of the monomer composition stirred at a speed of 1000 rpm or more To form a hydrogel polymer; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, wherein the concentration of the water-soluble ethylenically unsaturated monomer included in the monomer composition is 40 weight ¾ »to 60 weight ¾>, Drying, pulverizing, and classifying the hydrogel polymer to form a base resin powder may include a coarse milling step of grinding the particle size of the hydrogel polymer so as to have a particle diameter of 2 kPa to 10 kPa. ^{At a} temperature above ^° C, a process for producing a super absorbent polymer may be provided that proceeds with a frequency of 15 Hz or higher.

In addition, the production method of the other embodiment comprises a layered silicate-based particles, foamed crab, internal cross-linking agent and at least a portion of the water-soluble ethylenically unsaturated monomer having a neutralized acid group, crosslinked polymerization of the monomer composition stirred at a speed of 1000 rpm or more To form a hydrogel polymer; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, wherein the concentration of the water-soluble ethylenically unsaturated monomer included in the monomer composition is 40 wt% to 60 wt%, and the hydrogel The particle diameter of the polymer is from 2 隱 to 10 讓 And coarsely pulverizing the pulverizing step, and before or after the coarse pulverizing step, further comprising adding water in an amount of less than 20 parts by weight, based on 100 parts by weight of the hydrogel polymer. Manufacturing methods may be provided.

On the other hand, the production method of the other embodiment comprises a layered silicate-based particles, a blowing agent, an internal crosslinking agent and at least a portion of the water-soluble ethylenically unsaturated monomer having a neutralized acid group, crosslinked polymerization of the monomer composition stirred at a speed of 1000 rpm or more To form a hydrogel polymer; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, and drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, the hydrogel polymer Coarse grinding step of grinding so that the particle diameter of 2 to 10 隱, wherein the coarse grinding step proceeds at a frequency of 15 Hz or more, ^{at a} temperature of 50 ^° C or more, before or after the coarse grinding step, With respect to 100 parts by weight of the hydrogel polymer, a method for preparing a super absorbent polymer may be provided further comprising adding water in an amount of less than 20 parts by weight. On the other hand, the production method of the other embodiment comprises a layered silicate-based particles, foamed crab, internal crosslinking agent and water-soluble ethylene-based unsaturated monomer having at least a portion of the acid group is increased, crosslinking the monomer composition stirred at a speed of 1000 rpm or more Polymerizing to form a hydrogel polymer; And drying, pulverizing and classifying the hydrogel polymer to form a base resin powder, wherein the concentration of the water-soluble ethylenically unsaturated monomer included in the monomer composition is 40 wt% to 60 wt%. Drying, pulverizing and classifying the gel polymer to form a base resin powder includes a coarse pulverizing step of pulverizing the particle diameter of the hydrogel polymer so as to have a particle diameter of 2 kPa to 10 kPa, wherein the co-pulverizing step is 50 ^° C. 20 parts by weight, with respect to 100 parts by weight of the hydrogel polymer before or after the coarse grinding step, at a frequency of subphase. A method of preparing a super absorbent polymer may be provided further comprising adding water in a bay amount.

The superabsorbent polymer obtained according to the above-described manufacturing method may exhibit very excellent properties with improved physical properties such as water-retaining capacity and absorption rate, and diaper It can exhibit excellent various physical properties that can be suitably used for sanitary products. Specifically, the super absorbent polymer obtained by the method of preparing the superabsorbent polymer according to another embodiment has an apparent density (Bulk Densi ty, B / D) of 0. or higher, or 0.55 g / m £ to 1.0

Or 0.55 to 0.70. When the apparent density of the superabsorbent polymer is excessively reduced to less than 0.55 g / m ^, the volume of the superabsorbent polymer is relatively increased, and more storage space is required, thereby reducing storage efficiency. In addition, when the superabsorbent polymer is applied to a manufacturing process such as a diaper, the superabsorbent polymer particles may be stagnant without being smoothly injected, thereby reducing the efficiency of the process.

 【Effects of the Invention】

 According to the present invention, there can be provided a high absorbent resin having an improved absorption rate and high gallon density, and a manufacturing method thereof.

 [Brief Description of Drawings]

 Figure 1 schematically shows the structure of the unit crystal of the layered silicate particles used in the example.

 [Specific contents to carry out invention]

 The invention is explained in more detail in the following examples. However, the following examples are merely to illustrate the present invention, the content of the present invention is not limited by the following examples.

<Examples 1 and 2, Comparative Examples 1 and 2: Preparation of superabsorbent polymers having different post-treatment amounts>

 Reality U

 Bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide [IGARCURE 819] was added to 226 g of acrylic acid and mixed for 5 minutes. Then, polyethylene glycol diacrylate (Mi ramer M280) 4 was used as a crosslinking agent. 1 g was added and mixed for 10 minutes to prepare a monomer solution.

Laponite RD 1.6g was added to 155g of ionized water as a silicate type particle | grain, and it mixed for 30 minutes. Then, 1.7 g of sodium persulfate, a thermal polymerization initiator, was added thereto, dissolved in ionic water until completely dissolved, and then 8.8 g of sodium bicarbonate was used as a blowing agent. The mixture was mixed for 10 minutes to prepare a mixed aqueous solution.

 A caustic soda solution was prepared by mixing 192 g of ionized water with 661 g of 32% caustic soda (NaOH).

 483 g of acrylic acid was added to a 2L double-jacketed glass reaction vessel flowing at 20 ° C., and 54.7 g of the monomer solution was added thereto and mixed for 5 minutes. Thereafter, the caustic soda solution was added for 10 minutes and neutralized. The temperature was raised to about 65 ° C by the heat of neutralization, and waited until the angle was reduced to 46 ° C, the mixed aqueous solution 40. After adding 8g and mixing for 1 minute, a monomer composition was prepared by stirring at a speed of pump motor 6000 rpm and agitator 6900 rpm using a high shear force stirring device (dynami c mechani ca l system, DMS).

 The monomer composition was introduced into a supply unit of a polymerization belt composed of a continuously moving conveyor belt, irradiated with ultraviolet light for 1 minute (irradiation amount: 2 mW / ctf) with a UV irradiation device having a 10 mW illuminance, and waited for 2 minutes, 5 cm * After cutting into 5 cm size, 100 g (18.6 phr) of ionized water was added and absorbed to obtain a hydrous gel polymer.

 After transferring the hydrogel polymer to a cutter, it was ground at 25 ° C, 15.8hz conditions. Subsequently, the pulverized hydrogel polymer was dried in a hot air dryer at 180 ° C. for 40 minutes, and the dried hydrogel polymer was pulverized with a hammer mill grinder. Subsequently, a polymer having a particle size (average particle diameter size) of 150 βΆ to 850 was classified using a sieve, and a polymer having a particle size (average particle size size) of 300 im to 600 mm 3 was further classified to prepare a super absorbent polymer. It was. Conduct female 12

 A super absorbent polymer was prepared in the same manner as in Example 1, except that ion water was not added when preparing the hydrogel polymer. Compare ^] 1

Super absorbent polymer was prepared in the same manner as in Example 1, except that 195 g (36.7 phr) of ionized water was added to prepare the hydrogel polymer. Comparative Example 2 A superabsorbent polymer was prepared in the same manner as in Example 1, except that 145 g (27.0 phr) of ionized water was added to prepare the hydrogel polymer.

 <Examples 3 to 5, Comparative Example 3: Preparation of a super absorbent polymer having a different monomer concentration>

 Example 3

 0.45 g of bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide [IGARCURE 819] was added to 213.5 g of acrylic acid and mixed for 5 minutes to prepare a photoinitiator solution.

 After adding 0.38 g of sucrose ester (Ryoto s-1670) to 150.3 g of acrylic acid, 10.8 g of polyethylene glycol diacrylate (Mw = 508) [Mi ramer M280] was added as a crosslinking agent and mixed for 10 minutes to prepare a crosslinking agent solution.

 In 154.7 g of ionized water, 1.9 g of laponite RD was added as a silicate particle, followed by mixing for 30 minutes. Then, 3.5 g of sodium bicarbonate was added as a blowing agent and mixed for 10 minutes to prepare a mixed aqueous solution.

 14.7 g of sodium persulfate, a thermal polymerization initiator, was added to 132.6 g of ionized water, and dissolved until completely dissolved in ionized water, thereby preparing a thermal polymerization initiator solution.

 A caustic soda solution was prepared by mixing 117 g of ionized water with 624 g of 32% caustic soda (NaOH).

20 ^° C nyaenggak number into a 2L acrylate 428g double jacket glass half unggi flowing, the photo-initiator solution was 17, was five minutes into a common hapha crosslinking agent solution 15.8g. Thereafter, the caustic soda solution was added for 10 minutes and neutralized. The temperature rose to about 65 ^° C by the heat of neutralization, and waited until the ^angle was detected at 46 ^° C, and then mixed for 1 minute with 9.2 g of the thermal initiator solution and 38. 1 g of the blowing agent solution. A monomer composition was prepared by stirring at a speed of 6000 rpm and a stirrer 6900 rpm using a dynami c mechanical system (DMS). At this time, the monomer concentration contained in the monomer composition was 45.9% by weight.

The monomer composition was introduced into a supply section of a polymerization vessel consisting of a continuously moving conveyor belt, irradiated with ultraviolet light for 1 minute (irradiation amount: 2 mW / cirf) with a UV irradiation device having a 10 mW illuminance, and waited for 2 minutes, 5 cm * After cutting into 5 cm size, 40 g of ionized water was added and absorbed to obtain a hydrous gel polymer. The hydrogel polymer was transferred to a cutter and then ground at 80 ^° C. and 25hz. Next, the dry pulverized hydrogel polymer in a hot-air drier at 180 ^° C for 40 minutes, and was ground to the dried hydrogel polymer in the end of the hammer mill. By using a sieve, the superpolymer having a particle size (average particle size) of 150 to 850 was classified, and the polymer having a particle size (average particle size) of 300 to 600 was classified to prepare a super absorbent polymer. . Implementation ^ 14

 0.43 g of bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide [IGARCURE 819] was added to 204.8 g of acrylic acid and mixed for 5 minutes to prepare a photoinitiator solution.

 0.36 g of sucrose ester (Ryoto s-1670) was added to 144.2 g of acrylic acid, and 10.4 g of polyethylene glycol diacrylate (Mw = 508) [Mi ramer M280] was added as a crosslinking agent, followed by mixing for 10 minutes to prepare a crosslinking agent solution.

 1.9 g of laponite RD was added to 148.4 g of ionized water as a silicate particle, followed by mixing for 30 minutes. Then, 3.3 g of sodium bicarbonate was added as a blowing agent and mixed for 10 minutes to prepare a mixed aqueous solution.

 17.2 g of sodium persulfate, a thermal polymerization initiator, was added to 127.2 g of silver water, and dissolved until dissolved completely in ionized water, thereby preparing a thermal polymerization initiator solution.

 A caustic soda solution was prepared by mixing 163.4 g of ionized water with 598.5 g of 32% caustic soda (NaOH).

20 ^° C cooling water is put into a 2L 410.7g acrylic acid to the double jacket glass half unggi flowing, the photoinitiator solution 16.8g, was five minutes into a common hapha crosslinking agent solution 15.2g. Thereafter, the caustic soda solution was added for 10 minutes and neutralized. The temperature rose to about 65 ^° C by the heat of neutralization, and waited until the ^angle was detected at 46 ^° C, and then mixed with 8.8 g of the thermal initiator solution and 36.6 g of the blowing agent solution for 1 minute and then mixed with a high shear force agitator (dynami c Pump motor using mechani cal system (DMS)

The monomer composition was prepared by stirring at 6000 rpm and a stirrer 6900 rpm. At this time, the monomer concentration contained in the monomer composition was 44.0% by weight.

Polymerization consisting of a conveyor belt continuously moving the monomer composition Into the feeder of the machine, irradiate the Jawa line for 1 minute with a 10mW irradiance UV irradiation device (irradiation amount: 2mW / cirf), wait for 2 minutes, cut into 5cm * 5cm size, absorb 40g of ionized water To obtain a hydrous gel polymer.

After transferring the hydrogel polymer to a cutter, it was ground at 80 ^° C, 25hz conditions. Subsequently, the pulverized hydrogel polymer was dried in a hot air dryer at 180 ^° C. for 40 minutes, and the dried hydrogel polymer was pulverized with a hammer mill grinder. For this, a sieve is used to classify a polymer having a particle size (average particle size) of 150 / m to 850, and then to classify a polymer having a particle size (average particle size) of 300 μπι to 600 to superabsorbent polymer. Was prepared. Example 5

 Photoinitiator solution was prepared by adding 0.41 g of bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide [IGARCU E 819] to 195.4 g of acrylic acid and mixing for 5 minutes.

 0.36 g of sucrose ester (Ryoto s-1670) was added to 137.6 g of acrylic acid, and 9.9 g of polyethylene glycol diacrylate (Mw = 508) [Mi ramer M280] was added as a crosslinking agent, followed by mixing for 10 minutes to prepare a crosslinking agent solution.

 2.2 g of laponite RD was added as a silicate particle to 175.4 g of ionized water, followed by mixing for 30 minutes. Then, 3.9 g of sodium bicarbonate was added as a blowing agent and mixed for 10 minutes to prepare a mixed aqueous solution.

 13.5 g of sodium persulfate, a thermal polymerization initiator, was added to 121.4 g of ionized water and dissolved until completely dissolved in ionized water to prepare a thermal polymerization initiator solution.

 A caustic soda solution was prepared by mixing 212.9 g of ionized water with 571.2 g of 32% caustic soda (NaOH).

392 g of acrylic acid was added to a 2L double-jacketed glass reaction vessel flowing ^at 20 ^° C., and 16. lg of the photoinitiator solution and 14.5 g of the crosslinker solution were mixed for 5 minutes. Thereafter, the caustic soda solution was added for 10 minutes and neutralized. The temperature rose to about 65 ^° C by the heat of neutralization, and after waiting until it cooled to 46 ^° C, 8.4 g of the thermal initiator solution and 34.9 g of the blowing agent solution were mixed and mixed for 1 minute, followed by a high shear stirrer (dynami c Pump motor using mechanical system (DMS) The monomer composition was prepared by stirring at 6000 rpm and a stirrer 6900 rpm. At this time, the monomer concentration contained in the monomer composition was 42% by weight.

 The monomer composition was introduced into a supply unit of a polymerizer consisting of a continuously moving conveyor belt, and irradiated with ultraviolet rays for 1 minute (irradiation amount: 2 mW / crf) with a UV irradiation apparatus having a 10 mW illuminance, and then waited for 2 minutes, 5 cm * After cutting into 5 cm size, 40 g of ionized water was added and absorbed to obtain a hydrous gel polymer.

The hydrogel polymer was transferred to a cutter and then ground in a 80 ^ 25hz condition. Subsequently, the pulverized hydrogel polymer was dried in a hot air dryer at 180 ^° C. for 40 minutes, and the dried hydrogel polymer was pulverized with a hammer mill grinder. For example, a sieve is used to classify a polymer having a particle size (average particle size) of 150 to 850, and then to classify a polymer having a particle size (average particle size) of 300 m to 600 mm to obtain a superabsorbent polymer. Prepared. 13 F

 A high absorbency resin was prepared in the same manner as in Example 3, except that the monomer concentration contained in the monomer composition was adjusted to 39 wt% when the monomer composition was prepared.

<Examples 6 to 7, Comparative Example 4: Preparation of superabsorbent polymer having different grinding speeds>

 Reality 16

 220.2 g of acrylic acid was added with bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide [IGRARCURE 819] 0.1 g and 0.44 g of sucrose ester (Ryoto s-1670) as a photopolymerization initiator, followed by mixing for 5 minutes. A monomer solution was prepared by adding 4.0 g of polyethylene glycol diacrylate (Mi ramer M280) as a crosslinking agent and mixing for 10 minutes.

Laponite RD 1.6g was added to 155g of ionized water as a silicate type particle | grain, and it mixed for 30 minutes. Thereafter, 4.4 g of sodium persulfate as a thermal polymerization initiator was added thereto, and dissolved until completely dissolved in ionized water. Then, 8.8 g of sodium bicarbonate was added as a blowing agent and mixed for 10 minutes to prepare a mixed aqueous solution. A caustic soda solution was prepared by mixing 192 g of ionized water with 661 g of 32% caustic soda (NaOH).

483 g of acrylic acid was added to a 2L double-jacketed glass repellent flowing ^at 20 ^° C., and 54.8 g of the monomer solution was added thereto and mixed for 5 minutes. Thereafter, the caustic soda solution was added for 10 minutes and neutralized. The temperature was raised by junghwayeol to about 65 ^° C, wait until nyaenggak to 46 ^° C, the heunhap aqueous _solution, 41.4g combined into a common 1 min and then, the high shear force stirrer (dynami c mechani cal system, DMS A monomer composition was prepared by stirring at a speed of 6000 rpm and a stirrer 6900 rpm using a pump motor.

The monomer composition was introduced into a feeder of a polymerization reactor consisting of a continuously moving conveyor belt, irradiated with ultraviolet light for 1 minute (irradiation amount: 2 mW / α ² ) with a UV irradiation device having a 10 mW illuminance, and then waited for 2 minutes, 5 cm * After cutting into 5 cm size 100 g of ionized water was absorbed to obtain a hydrous gel polymer.

After transferring the hydrogel polymer to a cutter, it was ground at 90 ^° C, 25hz conditions. Subsequently, the pulverized hydrogel polymer was dried in a hot air dryer at 180 ^° C. for 40 minutes, and the dried hydrogel polymer was pulverized with a hammer mill grinder. This sieve is used to classify polymers having a particle size (average particle size) of 150 μαι to 850 / 通, and to classify polymers having a particle size (average particle size) of 300 urn to 600 to superabsorbent polymers. Was prepared. Implementation ^ 17

 225.5 g of acrylic acid was added with bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide [IGARCURE 819] as a photopolymerization initiator and mixed for 18 minutes, followed by mixing with polyethylene glycol diacrylate (Mi ramer M280). 4. Add 1 g and mix for 10 minutes to prepare a monomer solution.

 Laponite RD 1.6g was added to 155g of ionized water as a silicate type particle | grain, and it mixed for 30 minutes. Thereafter, 1.7 g of sodium persulfate as a thermal polymerization initiator was added thereto, and dissolved until completely dissolved in ionized water. Then, 8.8 g of sodium bicarbonate was added as a blowing agent and mixed for 10 minutes to prepare a mixed aqueous solution.

Caustic soda solution by mixing 192 g of ionized water with 661 g of 32% caustic soda (NaOH) Was prepared.

483 g of acrylic acid was added to a 2L double-jacket glass reaction vessel flowing with 20 ^° C. cooling water, and 54.7 g of the monomer solution was added thereto and mixed for 5 minutes. Thereafter, the caustic soda solution was added for 10 minutes and neutralized. The temperature was raised by junghwayeol to about 65 ^° C, and then wait for it to cool to 46 ^° C, into the aqueous solution of 40.8g heunhap combined common 1 min and then, the high shear force stirrer (dynami c mechani cal system, DMS) By using a pump motor 6000 rpm, the stirrer was stirred at a speed of 6900 rpm to prepare a monomer composition.

 The monomer composition was introduced into a supply unit of a polymerizer consisting of a continuously moving conveyor belt, irradiated with ultraviolet rays for 1 minute (irradiation amount: 2 mW / cuf) with a UV irradiation apparatus having lOmW illuminance, and then waited for 2 minutes, 5 cm * After cutting into 5cm size, 100g of ionized water was added and absorbed to obtain a hydrous gel polymer.

The hydrogel polymer was transferred to a cutter and then ground at 90 ^° C. and 15.8 hz. Subsequently, the pulverized hydrogel polymer was dried in a hot air dryer at 180 ^° C. for 40 minutes, and the dried hydrogel polymer was pulverized with a hammer mill grinder. Subsequently, a polymer having a particle size (average particle diameter size) of 150 to 850 mm 3 was classified using a sieve, and a polymer having a particle size (average particle size size ⁾ of 300 to 600 mm 3 was again classified to prepare a super absorbent polymer. . Comparison

After transferring the hydrogel polymer to a cutter, a super absorbent polymer was prepared in the same manner as in Example 6, except that the hydrogel polymer was ground at 90 ^° C. and 10 hz.

<Experimental Example: Measurement of Physical Properties of Super Absorbent Polymers Obtained in Examples and Comparative Examples> Physical properties of the superabsorbent polymers prepared in Examples and Comparative Examples were measured by the following methods, and the results are shown in Tables 1 to 3 below. Shown in Experimental Example 1. Centrifugal water retention capacity for physiological saline (CRC, Centr i fuge Retent ion Capaci ty)

European Di sposabl es and Nonwovens According to the standard EDANA WSP 241.2, the centrifugal water retention capacity (CRC) was measured for the high absorbent resins of the examples and the comparative examples with no-load absorption ratio.

That is, after the resin W ₀ (g, about 0.2 g) of the examples and comparative examples were evenly placed in a non-woven bag and sealed, the solution was immersed in a physiological saline solution of 0.9 wt% aqueous sodium chloride solution at room temperature. did. After 30 minutes, the bag was centrifuged and drained at 250 G for 3 minutes, and then the mass W ₂ (g) of the bag was measured. Moreover, the mass Wg) at that time was measured after performing the same operation without using resin.

 Using each mass thus obtained, CRC (g / g) was calculated according to the following equation 1 to confirm the water holding capacity.

 [Calculation 1]

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

 In the above formula 1,

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

 W g) is the weight of the device measured after dehydration at 250 G for 3 minutes using a centrifuge without using a super absorbent polymer,

W ₂ (g) is a device measured by submerging the superabsorbent resin in 0.9 wt% physiological saline at room temperature for 30 minutes and then dehydrating it at 250G for 3 minutes using a centrifuge. It is weight. Experimental Example 2. Water Soluble Component (Extractabl e content, EC)

 According to the EDANA method WSP 270.3, the content of the water-soluble component was measured for the super absorbent polymers of the Examples and Comparative Examples. Experimental Example 3. Absorption Rate (Swirl Test, Vortex-test)

50 ι of 0.9 wt% NaCl solution was added to a 100 mi beaker, followed by stirring at 600 rpm using a stirrer, and 2.00 g of the superabsorbent polymers according to the examples and the comparative example were added, respectively. And the time until the vortex of the liquid which arose by stirring disappeared and a smooth surface was measured was measured. Experimental Example 4. Bulk density (B / D)

 100 g of the superabsorbent polymers of the Examples and Comparative Examples were taken through a standard fluidity measuring device orifice and received in a 100 ml volume container, and the superabsorbent resin was scraped off horizontally to adjust the volume of the superabsorbent resin to 100 ml. The weight of the super absorbent polymer except the container was measured. The apparent density corresponding to the weight of the superabsorbent polymer per unit volume was obtained by dividing the weight of the superabsorbent polymer only by 100 ml of the superabsorbent polymer. Experimental Example 5. Moisture Content (%)

 For the hydrogel polymers obtained in Examples and Comparative Examples, the moisture content was obtained by calculating the weight loss due to moisture evaporation in the process of drying through infrared heating. At this time, the drying condition was set to 20. minutes, including 5 minutes in the temperature rise step in a way that the temperature is maintained at 180 after the temperature is raised to about 180 at room temperature.

Table 1

 Example 1 to 2, Comparative Examples 1 to 2 Superabsorbent polymer test results

As shown in Table 1, the superabsorbent polymers obtained in Examples 1 and 2 each had a hanging density of 0.56 g / mi and 0.55 g /, and a comparative example having an apparent density of 0.51 g / l and 0.53 g /, respectively. Compared with the superabsorbent polymers 1 and 2, it was confirmed that the apparent density increased. [Table 2]

 Examples 3 to 5, the superabsorbent polymer experimental example results prepared in Comparative Example 3

 As shown in Table 2, the superabsorbent polymers obtained in Examples 3 to 5 each had a high apparent density of 0.59 g /, 0.58 g /, and 0.56 g / m £, and each had a apparent density of 0.54 g /. Compared to the super absorbent polymer of 3, the apparent density was confirmed to increase.

 On the other hand, when the concentration of the monomer composition is excessively increased to more than 45.9% by weight, precipitation occurs in the reaction product in the neutralization process, and thus the polymerization of the super absorbent polymer cannot proceed.

Table 3

 Examples 6-7, superabsorbent water quantitative experimental example results prepared in Comparative Example 4

 As shown in Table 3, the superabsorbent resins obtained in Example 6 7 had a high apparent density of 0.60 g / m £ and 0.56 g / ^, respectively, and had a gallon density of 0.54 g / ^. It was confirmed that the apparent density increased compared to the super absorbent polymer.

Claims

[Claim]

 [Claim 1]

 A base resin powder comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer having at least a portion of neutralized acid groups,

 In the base resin powder, a plurality of pores having a diameter of 1 or more are formed,

 The crosslinked polymer comprises layered silicate particles dispersed in its crosslinked structure,

 Apparent density is 0. Superabsorbent polymers of 55 g / mt or more.

[Claim 2]

 According to claim 1,

 The plurality of pores of at least one diameter formed in the base resin powder includes micropores having a diameter of 10 to loom, superabsorbent resin.

[Claim 3]

 The method of claim 1,

 Superabsorbent polymer with a removal time of vortex of 60% by 0.9 rpm of 50% NaCl solution at 600 rpm.

[Claim 4]

 The method of claim 1,

 The layered silicate-based particles are super absorbent polymers formed on at least one surface of the metal oxide layer and the metal oxide layer containing a metal oxide, comprising a unit crystal including a silica layer containing silica.

[Claim 5]

 The method of claim 1,

The layered silicate particles have a maximum diameter of 1 ran to 100 ran and a height of 0. Super absorbent polymer having a structure of Olran to 20 nm.

[Claim 6]

 The method of claim 1,

 The layered silicate-based particles are superabsorbent resins contained in 0.01 parts by weight of 30 parts by weight based on 100 parts by weight of the base resin powder.

[Claim 7]

 The method of 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 Anionic monomers of propanesulfonic acid or 2- (meth) acrylamide-2—methyl propanesulfonic 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

 Amino group-containing unsaturated monomers of (Ν, Ν) -dimethylaminoethyl (meth) acrylate or (Ν, Ν) -dimethylamino propyl (meth) acrylamide and their quaternized compounds; Superabsorbent polymer comprising one or more selected from the group consisting of.

[Claim 8]

 The method of claim 1,

 The crosslinked polymer is a super absorbent polymer comprising a crosslinked structure in which the polymer chains of the water-soluble ethylenically unsaturated monomer are crosslinked through a crosslinkable functional group of an internal crosslinking agent.

[Claim 9]

 The method of claim 1,

The crosslinked polymer may have an internal value including a polyfunctional acrylate compound in which the water-soluble ethylenically unsaturated monomer has a plurality of ethylene oxide groups. A super absorbent polymer comprising a crosslinked polymerizer polymerized in the presence of a companion.

[Claim 10]

 The method according to claim 8 or 9,

 The internal crosslinking agent is polyethylene glycol diacrylate (PEGDA), glycerin diacrylate, glycerin triacrylate, unmodified or ethylated trimethylol triacrylate (TMPTA), nucleic acid diol diacrylate, and triethylene glycol A super absorbent polymer comprising at least one member selected from the group consisting of diacrylates.

[Claim 11]

 At least a part comprising a base resin powder comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer having a neutralized acid group,

A plurality of pores of diameter 1 or more are formed in the base resin powder,

 Highly absorbent resin with an apparent density of at least 55 g / mi and a time for removing vortex generated when stirring 50 mi of 0.9 wt% NaCl solution at 600 rpm at 54 seconds or less.

[Claim 12]

 Forming a hydrogel polymer by crosslinking and polymerizing a monomer composition comprising a layered silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least a part of which is neutralized acidic group, and stirred at a speed of at least 1000 rpm; And

 Drying, pulverizing, and classifying the hydrogel polymer to form a base resin powder,

 The concentration of the water-soluble ethylene-based unsaturated monomer contained in the monomer composition is 40% to 60% by weight, a method for producing a super absorbent polymer.

[Claim 13] Forming a hydrogel polymer by crosslinking and polymerizing a monomer composition comprising a packed silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least a part of which is neutralized acidic group, and stirred at a speed of at least 1000 rpm; And

 Drying, pulverizing and classifying the hydrogel polymer to form a base resin powder,

 Drying, pulverizing and classifying the hydrogel polymer to form a base resin powder may include a coarse grinding step of grinding the hydrogel polymer so that the particle diameter of the hydrogel polymer is 2 kPa to 10 kPa.

The ultra-pulverizing step proceeds with a frequency of 15 Hz or more, at a temperature of 50 ^° C or more, the method of producing a super absorbent polymer.

[Claim 14]

 Forming a hydrogel polymer by crosslinking and polymerizing a monomer composition comprising a layered silicate-based particle, a blowing agent, an internal crosslinking agent, and a water-soluble ethylenically unsaturated monomer having at least a part of which is neutralized acidic group, and stirred at a speed of at least 1000 rpm; And

 Drying, pulverizing and classifying the hydrogel polymer to form a base resin powder,

 Drying, pulverizing, and classifying the hydrogel polymer to form a base resin powder includes a coarse grinding step of pulverizing the particle size of the hydrogel polymer so as to have a particle diameter of 2 GPa to 10 GPa,

 Before or after the coarse grinding step,

 100 parts by weight of the hydrogel polymer, further comprising the step of adding water in an amount of less than 20 parts by weight, a method for producing a super absorbent polymer.

[Claim 15]

 The method according to any one of claims 12 to 14,

1 part by weight to 50 parts by weight of layered silicate particles are used with respect to 100 parts by weight of the blowing agent, a method for producing a super absorbent polymer. [Claim 16]

 The method according to any one of claims 12 to 14,

 The blowing agent is azodicarbonamide, azodicarboxyamide, benzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, toluenesulfonylhydrazide, azobisisobutyronitrile, azodicarboxylic acid barium and bicarbonate A method for producing a super absorbent polymer, comprising one or more selected from the group consisting of sodium.