[Technology]
Mutual citations and related application (s)
This application is dated 15 December 2017 Korea Patent No. 10-2017-0173553 and export oenje
November 13, 2018 claims the benefit of priority based on the Korea Patent Application No. 10-2018-0139102, and all information disclosed in the literature of Korea that the patent application is included as part of the specification.

The present invention and showing a solid addition to the basic absorption performance, improved absorption rate and the barrel-component relating to the water-absorbent resin and a production method thereof.

[Background Art]

Godeup aqueous resin (Super Absorbent Polymer, SAP) as a synthetic polymeric material having the ability to absorb water of about five-hundred to about one thousand times the Lanza body weight, developers, each SAM (Super Absorbency Material), AGM (Absorbent Gel material), etc. are each named with a different name. superabsorbent polymer as described above is to begin commercialization of physiological instruments, and now children's diapers, etc. sanitary ware besides horticultural sheet for soil repair filler, engineering, construction index material, a nursery for , it is widely used for a material such as freshness-retaining agent, and a poultice of the food distribution areas.

In most cases, there Such super-absorbent resin is widely used in diapers and sanitary napkins equipotential saengjae art, for this purpose it is necessary to exhibit a high absorption capacity for such water, and should have absorbed moisture to an external pressure not get out, whereby in addition, it is necessary to exhibit excellent liquid cylinder (permeability) to maintain the well in the form of a water absorbs volume expansion (swelling) state.

Recently, there is a tendency that, depending on the requirements for the thin diaper to expand, reducing the pulp fiber material content in the diaper, and the relatively high increase in the proportion of the water-absorbent resin. Therefore, a high performance was fibers of diaper material charge and the need to combine the water-absorbent resin, to have a high To this end, the high absorption capacity of the water-absorbent resin, as well as high absorption rate and the barrel-component. In particular, as the diaper is thinner, the diaper

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Because of the increase in urine, the cell concerned in the diaper according to the movement of the user baby, and demand for such a high absorption rate for a water-absorbent resin is a situation on the rise.

On the other hand, in order to indicate a higher barrel liquid by the high absorbent resin mentioned above, there is high above the five basic water-absorbent resin particles have to be a gap between to maintain its shape even after the swelling by absorbing water particles and the particles maintain. This is because the gap between the particles can guarantee an excellent bottle of liquid absorbent resin and the euro act. Therefore, in order to provide a water-based resin gorop showing an improved barrel-component and other excellent physical properties, such choices based resin, the surface 10 may need to be prepared to exhibit a higher gel strength through crosslinking.

In addition, the high to indicate that the water absorbent resin high absorption rate than, have a large surface area, it is necessary to represent a porous structure such as a large number of fine pores formed therein. This is a super-absorbent resin is produced from the previous bar to apply the foaming agent or the like having a porous structure such as this. However, such superabsorbent 15 resin, since the risk becomes non-uniform, such as in the form of particles after crushing size, during mixing of the additives for improving the state or physical properties of the surface cross-linked after the pulverization, a surface crosslinking or unevenly done, the application of the additive in many cases it is made non-uniform. As a result, and to form a porous structure such as the prior art implementation of the high absorption rate of a water-absorbent resin, barrel-component 0 ina that this decrease other physical properties such as the ability to absorb 20 in many cases.

Thus, while maintaining the excellent absorption performance, and the development of a technology that can and showing the improved tube and liquid absorption rate at the same time provide water-absorbent resin needs to continue.

[Detailed Description of the Invention]

25 [Technical Problem]

The present invention is to provide not only excellent been absorption performance, and improved absorption rate and the barrel-component and the like shown with the water absorbent resin and a production method thereof.

[Technical Solution]

3 0 The present invention ethylenically 2019/117482 1 »water-soluble acid having at least partially neutralized (1 ^ 1 {2018/013917

A base resin powder including a first cross-linked polymer of an unsaturated monomer; and

Gotop a water-based resin comprising a surface cross-linking increases to the first cross-linked polymer is formed on the base resin powder, has a second cross-linked polymer cross-linking a surface cross-linking agent is added to the medium,

The super-absorbent resin is high and an aspect ratio of less than 0.5 as defined by the shortest diameter / the longest diameter of each of the super-absorbent resin particles including a water-absorbent resin particles with 10% by number or more,

Inductive flow灰] of the physiological saline (0.685% by weight aqueous solution of sodium chloride); 10- 7 0 11 3 ) 30 (_10- 7 0 11 3 provides a super-absorbent resin having _).

The present invention also comprising the steps of: in the presence of a blowing agent, and an internal crosslinking agent, to form a hydrogel polymer comprising a first cross-linked polymer by cross-linking polymerization of the water-soluble ethylenically unsaturated monomer having at least partially neutralized acid;

To the hydrogel polymer gel crushing, drying, grinding and classifying, each forming a base resin mold containing less than an aspect ratio of 0.5 based resin powder, which is defined by the shortest diameter / the longest diameter of the base resin powder with at least 10% by number ; and the surface cross-linking agent and comprises a liquid medium, and from 20 to 251: in the presence of a temperature and a surface tension of 30 to 50 11 ^ / 111 of surface cross-linking solution in, and including the step of surface crosslinking by heating the base resin It provides a process for the production of the absorbent resin.

Hereinafter, there will be more fully describes the collection of specific embodiments and the water-absorbent resin and its production process according to the invention. However, it is to be presented as an illustration of the invention and thus is not limited by the scope of the invention, it is apparent to those skilled in the art are possible are various modifications to the embodiments within the scope of the invention. Additionally, "it included unless otherwise stated in this specification ," or

Box "containing" La not be construed to refer to and including without limitation any component (or components), except for the addition of the other component (or components).

According to one embodiment of the invention, the invention is based 2019/117482 1 »including a first cross-linked polymers of water soluble ethylenically unsaturated monomer having at least partially neutralized acid (1 ^ 1 {2018/013917

Resin powder; And a super-absorbent resin comprising a surface cross-linked layer which is formed on the base resin powder, including the second add a cross-linked second cross-linked polymer cross-linked polymer is 1 to mediate the surface cross-linking agent,

The super-absorbent resin is high and an aspect ratio of less than 0.5 as defined by the shortest diameter / the longest diameter of each of the super-absorbent resin particles including a water-absorbent resin particles with 10% by number or more,

Of physiological saline (0.685% by weight aqueous solution of sodium chloride)
10 · 7 « 11 3 _) is 30 (_10 111 3 _) is provided with a super-absorbent resin or higher.

Continuous experiments of the inventors of the present invention results, and, after a large particle aspect ratios in the presence of a blowing agent, such as at the time of cross-linking polymerization obtained above a certain level, the surface cross-linked liquid surface cross-linking step down using the same surface tension according to the manufacturing method described below as well as, excellent in absorption capacity as the fundamental proceed, it was confirmed that liquid tube and the absorption rate is improved and with that the water-absorbent resin produced, and may be provided, and completed the invention.

By default, the example super-absorbent resin wherein an implementation is in accordance with the load obtained proceed with foaming polymerization using a foaming agent such as in the polymerization process, a base resin powder and the super-absorbent resin particles after milling, and be manufactured relatively so as to have a small aspect ratio and a large surface area It has can be manufactured. For example, high shortest diameter / the aspect ratio, defined as a maximum diameter of 0.5 less and a water-absorbent resin particles 10% by number or more, or 10% by number to 60% by number, or 10% by number to the ratio of 50% by number of the water-absorbent resin particles It can be provided to include.

In this way, high in the manufacturing process of the absorbent resin, the base resin powder and the super-absorbent resin particles are obtained to include a small aspect ratio of the particles above a certain level, as the specific surface area increases, the example super-absorbent resin wherein one embodiment is higher than the It may refer to such as absorption rate.

However, to improve with this way when the aspect ratio of the formation above a certain level of small particles, it is difficult to proceed the surface cross-linked after uniformly in the like form of the particles non-uniform as a result high pressure absorption capacity and the barrel-component in the water absorbent resin, and the like It becomes difficult. This is the case of a small aspect ratio particles, because it takes place with an aspect ratio of surface cross-linking the non-uniform relative to the particle near the first.

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However, the base including the continuous experiments by the inventors, in a manner to be described below was used to obtain a surface cross-linking fluid having a relatively low surface tension, as with this progress the surface cross-linking, the aspect ratio is not more than a certain level of small particles resin powder excellent in surface cross-linking has also been confirmed that can uniformly form a surface cross-linked layer and having a strength which is estimated to be because the uniformly control the degree of penetration of the surface cross-linking solution is relatively shallow.

Therefore, the one embodiment the superabsorbent resin can exhibit a more and improved tube and the liquid absorption capacity under pressure with a high absorption rate. Such an implementation example and improved barrel-component represented by the water-absorbent resin and the like can be defined by the above-mentioned range.

Therefore, one embodiment the superabsorbent resin can be represented with the like absorption rate and barrel-component to be excellent in maintaining the fundamental absorption performance unlike the conventional wisdom is difficult to improve together with all, improved absorption rate and the barrel-component, more It can be preferably applied to the diaper such as sanitary material having a small thickness.

Hereinafter, one embodiment that will be described in more detail on the water-absorbent resin.

The "superabsorbent resin" as referred to herein refers to a base resin powder including a first cross-linked polymers of water soluble ethylenically unsaturated monomer having at least partially neutralized acid; And that means the water absorbent resin including the resin powder is formed on the base, wherein the added crosslinked with a surface cross-linked layer, including two cross-linked polymer with the surface cross-linking agent intermediate the first cross-linked polymer.

The water-soluble ethylenically unsaturated monomer and may be any monomer that is commonly used in the manufacture of a water-absorbent resin, non-limiting example, the water-soluble ethylenically unsaturated monomer to the number of days is a compound represented by the general formula (1):

Formula 1

In - 山

In the formula 1,

Is an alkyl group of 2 to 5 carbon atoms including an unsaturated bond,

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A hydrogen atom, a monovalent or divalent metal, an ammonium group or an organic amine salt. Suitably, the monomer may be at least one member selected from acrylic acid, methacrylic acid, and monovalent metal salts of these acids, the group consisting of a divalent metal salt, ammonium salt and organic amine salt. As such a water-soluble ethylenically unsaturated monomer used when acrylic acid or geuyeom advantageously improved absorbability and the obtained water-absorbent resin. In addition to the monomers maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-1-acryloyl ethane sulfonic acid, 2-1 ethanesulfonic acid, methacrylonitrile, 2-1 propane sulfonic acid (meth) acrylate, or 2- ( meth) acrylamide-2-anionic monomers and their salts of methylpropanesulfonic acid; (Meth) acrylamide, a substituted (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxy polyethylene glycol (meth) acrylate or polyethylene glycol (meth the group consisting of;) a hydrophilic monomer containing non-ionic acrylate; dimethylaminopropyl (meth) an amino group-containing unsaturated monomer and its quaternary products of acrylamide - and (外 C-dimethylaminoethyl (meth) acrylate or (byabi at least one selected from may be used.

Here, the water-soluble ethylenically unsaturated monomer having an acidic group, may be at least partially neutralizing the acid groups, preferably having partially neutralized the monomers with an alkali substance such as sodium hydroxide, potassium hydroxide, and ammonium hydroxide it can be used.

In this case, the neutralization degree of the monomer may be 40 to 95 mol%, or 40 to 80 mol%, or 45 to 75 mol%. Range of the degree of neutralization may be different depending on the final physical properties, the degree of neutralization precipitation is too high, the neutralized monomer may be difficult to polymerization proceeds smoothly, whereas if the degree of neutralization is too low, as well as degrade the polymeric absorbent significantly handling can exhibit properties such as hard rubber.

The means that the "first crosslinked polymer" refers to the above-described water-soluble ethylenically unsaturated monomer polymerization to the presence of internal cross-linking agent cross-linked, the "base resin powder, and means a material containing such a first crosslinked polymer. In addition, the 'second means cross-linked polymer, is, adding a cross-linked material by cross-linking the first polymer is a parameter for the surface cross-linking agent, and thus is formed on the base resin powder 2019/117482 1 »(1 ^ 1 {2018/013917

It may. Be decided to be described later to the surface cross-linking agent.

Such an implementation example super-absorbent resin is, as the base resin powder load obtained by foaming polymerization, as described above , there is such a base resin powder and the super-absorbent resin particle can be provided so as to have a relatively small aspect ratio. In more detail, in one embodiment the superabsorbent resin comprises a plurality of superabsorbent polymer particles, these gotop based on the total quantity of the water-based resin particles, for example, high definition the shortest diameter / the longest diameter of the water-absorbent resin particles an aspect ratio of 0.5 is less than the superabsorbent resin particles with 10% by number or more, or 10% by number to 80% by number, or 10% by number to 70% by number, 10% by number to 60% by number, or 10% by number to the ratio of 50% by number It can be included as.

In this case, the aspect ratio of the base resin powder and the super-absorbent resin particles, for instance, possible to calculate the shortest diameter ⑶ and a maximum diameter (not, by analyzing each of the particles by electron microscopy as shown in Figure 1, respectively, and It can calculate the aspect ratio of each of the base resin powder and the super-absorbent resin particles therefrom. To do this, from the aspect ratio data of each particle it was determined that the aspect ratio can be calculated the ratio of the number of particles is less than 0.5. For reference, the aspect ratio of the base resin powder and the super-absorbent resin particles are found to be equal to one another.

Thus, as one embodiment comprises a high water-absorbent resin particles have a small aspect ratio above a certain level, the fine pores between the base resin and the powder superabsorbent resin particles may be formed in a number ¾. When this porous which particulate is surface cross-linked layer formed on these, so between the fine pores can be water is much absorbed at a faster rate, an implementation example super-absorbent resin can exhibit a faster rate of absorption and absorption capability (beam SAT etc) have.

On the other hand, examples superabsorbent polymer described above be implemented, the basic pressure, or radish reduction absorption capability, absorption speed and the barrel-component is excellent, which is 0 ^,
the physical properties such as absorbency, 81, 30 seconds absorption speed or surface tension It can be defined by.

Specifically, in one embodiment the superabsorbent resin 30 min centrifugation beam SAT (01 for the for the physiological saline (0.9% by weight aqueous solution of sodium chloride) (: 25 to 35
may This centrifugation beam SAT (1 (: range to define a superior radish reduction absorbing performance indicated by the example super-absorbent resin implementation

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Can.

Centrifugation beam SAT (1 (:) for the saline solution is then absorbed by the saline solution through the superabsorbent polymer in 30 minutes can be calculated by the following formula 1 of:

[Equation 1]

Pyogeu poe {[\\, 2 (-此) - 0 (] / \ ¼) (}

In the formula 1,

\ ¥ 0 (initial weight of neungo absorbent resin (and,

\ ¥ 1 (is) is a weight measured after use and then impregnated with a saline solution for 30 minutes, the non-woven fabric bag not loaded gotop the water-based resin at room temperature, a centrifugal separator was dehydrated 3 minutes at 250 (3,

\ ¥ 2 (poe is a weight that is set after the impregnation and then in physiological saline for 30 minutes using a centrifuge dewatering 3 minutes at 250 (the third non-woven fabric bag into the superabsorbent polymer at room temperature.

In addition, the super-absorbent resin according to one embodiment is the physiological saline absorption capacity under pressure (g正) for 1 hour at 0 to (0.9 weight% aqueous sodium chloride solution) is 21 to
to 21.5
can. The absorption capacity under pressure!;! 1 ) The range can be defined by the ability to absorb high pressure, indicated by the example super-absorbent resin be implemented.

The absorption capacity under pressure!;! 1 ) is 0.7 over the superabsorbent polymer per hour
can be calculated according to the, following equation 2 after absorption of physiological saline under pressure:

[Formula 2]

Four = [ 4 (- \ (- /)

In the formula 2,

\ ¥ () (is) is the initial weight (is) of godop water-based resin, \ ¥ 3 and is also the sum of the unit weight that can weight the gorop water-based resin. And the high give it the load to the water-absorbent resin, \ ¥ 4 (the load (0.7 ? 81 is the sum of the weight device which can impart a load to the weight and the high water-absorbent resin of high after the for 1 hour under) which absorbs the saline solution to the water-absorbent resin, and water-absorbent resin.

In addition, one embodiment and centrifuged in the above-mentioned range is a water-absorbent resin beam SAT (01 (:

The super-absorbent resin may be in the following absorbency of 46 to 63g / g, which is defined by the formula 1, or 47 naeja 60g / g according to the indicated pressure and the absorption capacity (AUP):

[Equation 1]

Absorbency = CRC + AUP

In the formula 1,

CRC is the centrifuge and a beam of the SAT for 30 minutes for saline solution (0.9 weight% aqueous sodium chloride solution) of a water-absorbent resin, shows the beam SAT which is calculated as shown in the formula 1,

AUP is an absorption capacity of the pressure for one hour under a 0.7psi for physiological saline (0.9 wt% aqueous sodium chloride solution) of the super-absorbent resin, and the formula

It indicates the absorption capacity under pressure, as calculated by the formula 2.

Accordingly, one embodiment the superabsorbent resin is expressed as excellent absorption performance, such as the basic absorption and absorption under pressure retention can be suitably used for various sanitary materials.

Further, one embodiment the superabsorbent resin is inductive flow of saline solution (0.5% by weight aqueous solution of sodium chloride) (SFC, l (r 7 cm 3. s / g) is 30 (_l (T 7 cm 3 _s / g ) or more, or 35 (10 7 cm 3 s / g) or more, or 40 to 150 (10 W s / g) , or 42 to 130 ( . 1 (T 7 cm 3 can be a, s / g).

Inducing the saline flow properties (SFC) is a method well-known to those skilled in the art before, for example, it can be measured and calculated according to the method disclosed in U.S. Patent No. 5,562,646 arc column 54 to column 59.

The super-absorbent resin comprises a base resin powder to maintain a high gel strength, so for as comprising a uniform surface cross-linked layer having an excellent strength, the surface cross-linking proceeds, under certain conditions, may have a high gel strength as a whole and and thus it may exhibit improved saline flow induced (SFC) and excellent barrel-component.

Further, one embodiment the superabsorbent resin is used for such a surface cross-linking solution having a low surface tension, which will be described later according to the production / provided, as such, the surface tension (surface tension) of 60 to 75 mN / m, or from 60 to 73 It can be in mN / m.

This surface tension may, for example, 23土2 ° to the surface tension measuring instrument in whole costume C

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Use can be measured by Specific measuring method of the surface tension of such meals are described in the Examples which will be described later.

The high surface tension of the water-absorbent resin is beam SAT, pressure absorption capacity, whole liquid as the leakage of urine (1 to 1 in the diaper comprising the gotop aqueous resin with properties that are separated ¥ can be a that can evaluate) scale. The the surface tension is high and the water-absorbent resin swelling in saline, means that the surface tension was measured for the salt, and, in the case lower the surface tension of the water-absorbent resin is likely to have leakage of urine phenomenon etc. diaper is prepared by including the same result. According to an embodiment the superabsorbent resin, one can reduce the likelihood of leaks produce high quality hygiene products by having a liquid such as high barrel while maintaining the surface tension of the appropriate range. If the high that a surface tension of the water-absorbent resin is too low, the urine fountain phenomenon, that is, may be rewet is increased, if increased over the surface tension, the surface cross-linked layer forming non-uniform physical properties such as barrel-component be reduced have.

On the other hand, the above-described one days embodiment superabsorbent polymer is from about 0.16 § when a super-absorbent resin swelling under 0.3 pressurized condition by the physiological saline solution introduced through the mesh (11 ^ 11) of the cylindrical cylinder bottom, 30 seconds topsu speed 1.5111111 / 111111 or more, or 1.7111111 / 111 to 3.0111111 / 11 ^ 11, or 1.801111 / 11 ^ 11 to rheometer height change of the top plate unit may be as 2.6111111 / 111111. this 30 superabsorbent rate and the volume expansion of the water-absorbent resin as the absorption divided by the time (30 seconds) value can be measured and calculated.

The super-absorbent resin is high gel strength and thus indicating excellent barrel-component in accordance , at the same time an excellent absorption rate, which is defined by the above-described 30 superabsorbent speed range according to the particle size distribution during the production process is controlled has a porous structure inside It can be expressed. Thus, the super-absorbent resin can be preferably used in a sanitary material such as a fiber material content of reduced pulp.

On the other hand, in the above-described one days embodiment superabsorbent resin, the base resin powder, a first cross-linked polymer is trimethylolpropane tri (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate contained in the , propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butane diol di (meth) acrylate, butylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate,

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Nucleic acid di (meth) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, di-pentaerythritol pentaacrylate, glycerin tri ( meth) acrylate and poly-penta (meth) acrylate-based first internal cross-linking agent the polyol is selected from the group consisting of Erie stall tetraacrylate; And an allyl (meth) acrylate 2 in the presence of an internal crosslinking agent, the monomer may be polymerized as a crosslinked polymer. By the application of more of these two kinds of particular internal cross-linking agent, even after proceeding the including one embodiment the superabsorbent resin is a gel, crushing and grinding, and can maintain a high gel strength, and therefore, more excellent barrel liquid and under pressure absorbing performance such as a it can be expressed.

Further, the above-mentioned water-absorbent resin is, move to, as will described in more detail below, it may be used in combination of two or more of the alkylene carbonate having 2 to 6 carbon atoms having a different carbon number at the time of surface cross-linking a surface cross-linking agent. Accordingly, the super-absorbent resin has a crosslinked structure to the surface cross-linking agent of said plurality of types of parameters to be included in the surface cross-linked layer.

Then, the surface cross-linking solution including such a surface cross-linking agent and a liquid medium may further include a surfactant, a predetermined polycarboxylic acid-based copolymer, a surface active agent or a carbon number of 6 or more aliphatic alcohols. In this way, multiple types of use of the surface cross-linking agent, and optionally, and having various physical properties which by a further component, the surface tension of the surface cross-linking solution is achieved with a relatively low specific range described above is included in the surface cross-linking solution is a water-absorbent resin finally manufacturing and be provided . have.

On the other hand, the above-described one embodiment and the water absorbent resin may have a particle size of 150 to 850 II. More specifically, the base resin powder containing it and that has at least 95% or more by weight of 150 to 850 particle diameter of the water absorbent resin, the fine powder having a particle size of less than 150_ may be less than 5% by weight. In this case, in which the particle size of the water absorbent resin may be pre-defined by the longest diameter of the above-mentioned super-absorbent resin particles.

Technical principles with a water-based resin godeup metatarsal to the overall physical properties of the above-described example one embodiment may be prepared is as follows.

First, when using a blowing agent such as cross-linking polymerization and to increase the degree of foaming, 2019/117482 1 »(1 ^ 1 {2018/013917

This allows a large number of fine pores and a large surface area include the form can form a hydrogel polymer. Grinding the gel for such a hydrogel polymer and thereafter . When proceeding to milling or the like, the higher the probability of break of a porous form due to the small aspect ratio particles, such as of the hydrogel polymer. Thus, the aspect ratio can be manufactured with the high ratio of the base resin powder particles low.

However, in case of a low aspect ratio particles, as the surface cross-linking absorbing liquid at a relatively high speed, it becomes the aspect ratio of the particle differ from those close to the degree of penetration characteristics and the surface of the surface cross-linking the liquid cross-linked to the first. For this reason, a high possibility that a non-uniform cross-linking occurs, which can result in the lowering of the bucket, such as liquid. However, when lowering the ongoing experiments, the surface of the surface tension of the crosslinking solution of the inventors of the present invention relatively, a depth of the surface cross-linking solution to penetrate the base resin powder becomes relatively low, the surface cross-linking agent to penetrate uniformly to the entire particles / can be distributed and, as a result, and improves the whole liquid including the water-absorbent resin can be manufactured by high-absorbent resin that meets the various physical properties of one embodiment.

On the basis of these technical principles, there is provided a method of manufacturing a super-absorbent resin in accordance with another embodiment of the invention.

This manufacturing method comprises the steps of forming a hydrogel polymer containing in the presence of a blowing agent, surfactant and internal cross-linking agent, and polymerization at least partially cross-link the water-soluble ethylenically unsaturated monomer having a neutralized acidic a first cross-linked polymer;

To the hydrogel polymer gel crushing, drying, grinding and classifying, further comprising an aspect ratio which is defined by each of the shortest diameter 厂 longest diameter of the base resin powder to form a base resin containing 0.5 less than the base resin powder with at least 10% by number heat-treating the above-mentioned base resin may be a step for cross-linking the surface under, and the surface cross-linking agent and the presence of includes a liquid medium, and 20 to a temperature and a surface tension of 30 to 50 to 25 yae 11 ^ / 111 of surface cross-linking solution; .

Hereinafter, the production method in detail for each step.

First, different implementations of the manufacturing method includes forming a hydrogel polymer by cross-linking polymerization. Specifically, the thermal polymerization of a monomer composition comprising a water-soluble ethylenically unsaturated monomer and a polymerization in the presence of an internal crosslinking agent dog body

Or by a photo-polymerization to form a hydrogel polymer.

Water-soluble ethylenic unsaturated monomer contained in the monomer additive composition are as previously described.

Further, the monomer composition may include a polymerization initiator commonly used in the production of superabsorbent polymer. Non-limiting examples of the polymerization initiator include thermal polymerization initiator or a photopolymerization initiator may be used in accordance with the polymerization method. However, even in light of the polymerization process, it occurs a certain amount of heat due to ultraviolet radiation, and also a certain amount of heat generated with the progress of the polymerization reaction exotherm, can be included to add a thermal polymerization initiation agent.

Here, the photopolymerization initiator is, for example, benzoin ethers (benzoin ether), dialkyl acetophenones (dialkyl acetophenone), hydroxyl-alkyl ketones (hydroxyl alkylketone), phenyl glyoxylic rate (phenyl glyoxylate), benzyl dimethyl ketal (Benzyl

There is at least one compound selected from the group consisting of amino-ketone (a-aminoketone) may be used - Dimethyl Ketal), acylphosphine (acyl phosphine) and alpha. Specific examples of the acylphosphine of that, commercial lucirin TPO, i.e., 2,4,6-trimethyl-to-be for trimethyl phosphine oxide, (2,4,6-trimethyl-benzoyl-tiimethyl phosphine oxide) lyrics-benzoyl have. More varied for the photopolymerization initiator Reinhold Schwalm book,: is disclosed in "UV Coatings Basics, Recent Developments and New Application (Elsevier 2007 years)" on page 115 of which, one can refer to it.

Further, the heat polymerization initiator and has a sulfate-based initiators, azo initiators, hydrogen peroxide, and at least one compound selected from the group consisting of ascorbic acid may be used. Specifically, the persulfate-based initiator and sodium sulfate (Sodium persulfate; Na 2 S 208), potassium persulfate (Potassium persulfate; K 2 S 2 O 8), ammonium persulfate (Ammonium persulfate; (NH 4) 2 S 208 ) the like are exemplified. Further, azo (Azo) based initiators include 2,2-azo bis- (2-amidinopropane) dihydrochloride (2, 2-azobis ( 2 _ amidinopropane) dihydrochloride), 2, 2-azobis- (N, N- dimethylene) isobutoxy Thira Mai Dean dihydrochloride (2,2-azobis- (N, N -dimethylene) isobiityramidine dihydrochloride), 2- ( carbamoyl-azo) isobutyronitrile (2- (carbamoylazo) isobutylonitril), 2, 2-azobis [2- ( 2 -imidazolin- 2 -yl) propane] dihydrochloride ( 2 , 2-azobis［2-(2-imidazolin_2-

yl) propane] dihydrochloride), 4, 4 - are exemplified such as ballet cyano rigs acid) (4,4-azobis- (4-cyanovaleric acid)) - azobis- (4. Than is disclosed in for a variety of thermal polymerization initiator Odian book, "Principle of Polymerization (Wiley, 1981 year)," page 203 of which, one can refer to it.

The polymerization initiator is from about 0.3 with respect to the monomer composition 001 may be added at a concentration of to 1% by weight. That is, when the concentration of the polymerization initiator is too low and may slow the rate of polymerization is not preferable be residual monomers are extracted in a large amount in the end product. On the other hand, the polymer chains forming a network, if a too high concentration of the polymerization initiator shorter It becomes the number is not preferable because the physical properties of the resin may be lowered such that the lower the pressure absorption capacity higher concentration of component for.

On the other hand, the monomer composition is also a cross-linking agent ( "internal crosslinking agent"), the saturable to improve the physical properties of the composition according to the polymerization of the water-soluble ethylenically unsaturated monomer. As the cross-linking agent for cross-linking inside the hydrogel polymer, which will be described later. " surface cross-linking agent "and can be used separately.

Specifically, the In other implementations the manufacturing method, the internal cross-linking agent than previously described two species, for example, polyol poly (meth) acrylate-based first internal crosslinking agent, and allyl (meth) acrylate of claim 2 with an internal cross-linking agent use, it can obtain a hydrogel polymer.

More specifically, the first internal cross-linking agent is trimethylolpropane tri (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylates, poly propylene glycol di (meth) acrylate, butane diol di (meth) acrylate, butylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, acid di (meth) acrylate, tri glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, di-pentaerythritol pentaacrylate, glycerin tri (meth) acrylate and pentaerythrityl stall tetraacrylate at least one member selected from the group consisting of Can be used, wherein the second internal cross-linking agent, allyl methacrylate or

It can be used allyl acrylate, and the like.

In addition, the first and the total content of the second internal cross-linking agent may be in an amount of 0.01 part by weight to 2 parts by weight, or from 0.05 to 1.8 parts by weight based on 100 parts by weight of a monomer composition including the internal crosslinking agent and monomer . Further, the first internal cross-linking agent: a second internal cross-linking agent is from 1: 1 to 10: can be used in a weight ratio of 1, thus to control the composition such as type and quantity range of the internal cross-linking agent other hand, the, water content of which will be described later hydrogel polymer , can be more effectively obtain a high water-absorbent resin to the metatarsal one implementation example, as physical property control. However, the larger the amount of the internal cross-linking agent is too, can be a basic absorption performance of the super-absorbent resin decreases.

On the other hand, the above-described monomer composition further comprises a further blowing agent. As the presence of such a blowing agent, the progress of the polymerization step by firing the polymerization process, the particles can be formed in a number having a low aspect ratio, a base resin powder and the super-absorbent resin particles having the previously described particle distribution cant obtained.

The foaming agent is foamed up and the polymerization to form a hydrogel polymer within the pore-forming a plurality of particles of a small aspect ratio, and serves to increase the surface area. The blowing agent may be used a carbonate, sodium bicarbonate (sodium bicarbonate), sodium carbonate (sodium carbonate), potassium bicarbonate (potassium bicarbonate), potassium carbonate (potassium carbonate), calcium bicarbonate (calcium bicarbonate), calcium example a carbonate (calcium bicarbonate), magnesium bicarbonate (magnesiumbicarbonate) or magnesium carbonate (magnesium carbonate) may be used. ·

In addition, the blowing agent may be added to the acrylic acid monomer of 100 parts by weight from about 0.01 to about 1.0 parts by weight, relative to, or about 0.03 to about 0.7 parts by weight, or from about 0.05 to about 0.6 weight concentration of. The amount of the blowing agent If it exceeds 1.0 parts by weight can result in problems for not only difficult to process the production due to the over-firing, and the excess gibung formed is small, the density of the water-absorbent resin distribution and storage. Furthermore, the 0.01 wt sire if there It may be minimal, the role as a blowing agent.

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In addition, the monomer composition may further comprise a foam stabilizer in order to optimize the pore formation by the foaming agent. These cell stabilizer is that which serves to maintain the form of the bubbles formed due to the blowing agent at the same time uniform distribution of the bubbles in the polymer around the region, and serves more effectively in the formation of low aspect ratio particles, increasing the surface area of ​​the polymer.

This bubble stabilizing agent can be used any ingredient used in the release of air bubbles and foam stabilizer during polymerization of the water-absorbent resin before, for example, it can be used, such as cationic, anionic or non-ionic surfactants.

The foam stabilizer to achieve the above how methacrylic acid monomer based on 100 parts by weight of 0.001 may be added in parts by weight to 0.1 parts by weight concentration of. The case of a bubble stabilizing agent is too low concentration, the role of stabilizing the bubble mimihayeo improved absorption rate effect difficult, whereas if too high a concentration. And lower the surface tension of water in the resin topsu diaper
may cause the like.

In addition, the monomer composition has an additive such as a thickener, a plasticizer, a preservation stabilizer, an antioxidant be further included, if necessary.

Then, this monomer composition, such as the above-described monomer, a polymerization initiator, an internal crosslinking agent - is - can be prepared state-of lysis solution-type solvent in the raw material.

At this time, a usable solvent as long as it can dissolve the above-mentioned raw material can be used without limitation of its construction. For example, the solvent roneun 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, cyclo hex rice, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol ethyl ether, toluene, xylene ten, butyrolactone, carbitol, methyl cellosolve acetate,
methyl can be used, acetamide, etc. or a mixture thereof.

And, forming a hydrogel polymer by polymerization of the monomer composition can be performed by conventional polymerization methods, the process is not particularly limited. Non-limiting examples, the polymerization process is divided into large thermal polymerization and photo polymerization according to the type of the polymerization energy source, if the progress of the thermal polymerization can be conducted in a reactor having an axis agitation, such as a kneader (kneader), a photo-polymerization when in process, it can be carried out in a reactor equipped with a movable conveyor belt.

For example, by putting the monomer composition into the reactor, such as the stirring shaft provided with a kneader, and heat-polymerized by supplying hot air, or heating the reactor herein can obtain a hydrogel polymer. At this time, depending on the form of a stirring shaft provided with a reactor hydrogel polymer discharged from the reactor outlet may be obtained with particles of a few millimeters to several centimeters. Specifically, the hydrogel polymer obtained there is cant obtained in various forms depending on the concentration and the injection rate of the monomer composition to be injected, usually (weight average) particle size of the modifying polymer is phosphorus sugel obtained from 2 to 50 mm. And, In one embodiment the other, but can be the case to proceed photo-polymerization of the above monomer composition, the hydrogel polymer in the form of a sheet obtained from a reactor equipped with a movable conveyor belt. That case that there the thickness of the sheet may vary depending on the concentration and the injection rate of the monomer composition to be injected, to ensure the production speed, but that the entire sheet can be uniformly polymerized, usually adjusted to a thickness of 0.5 to 10 cm desirable.

On the other hand, after forming a gel polymer by the above-described functions are cross-linked polymerization, the gel crushing the hydrogel polymer of the water content is controlled.

Grinder used in the gel crushing step, is limited to the configuration, but, specifically, a vertical cutter (Vertical pulverizer), turbo cutter (Turbo cutter), a turbo grinder (Turbo / grinder), rotary cutting mill (Rotary cutter mill), cutting mill (cutter mill), disc mill (disc mill), a piece crusher (Shred crasher), crusher (crusher), the chopper (chopper) and source plate type cutter (selected in the grinding machine the group consisting of disc cutter) but it can include any one, but is not limited to the above example.

The hydrogel fracture of the gel polymer may be carried out the particle size of the hydrogel polymer such that 0.01 mm to about 50 mm, or 0.01 mm to 30mm. That is, the hydrogel polymer to an increase in drying efficiency is less than 50 mm It is ground to a particle

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It is desirable. However, since excessive grinding may occur when the aggregation between particles, it is preferred that the hydrogel polymer is pulverized to at least 0.01 _ gel particles .

Further, the hydrogel of the gel polymer is crushed, the water content may be due to relatively low natanalsu performed on the phenomenon adhering the hydrogel polymer to the surface of the gel grinder. In order to minimize this phenomenon, if necessary, steam, water, a surfactant, a coagulation preventing agent (e.g.
, etc.); Persulfate-based initiators, azo initiators, hydrogen peroxide, thermal polymerization initiator, an epoxy-based crosslinking agent, a diol Example 01 ) class of cross-linking agent, two functional groups, or three cross-linking agent of the first functional group containing a crosslinking agent, a hydroxyl group which is a functional group or more acrylate functional groups etc. may be added to the hydrogel polymer.

After the above-described gel pulverization, it is possible to dry the hydrogel polymer. The drying may be more preferably from 0140 to 200 ° preferably 0, 120 to 250 ° may be carried out at a temperature of 150 to 200. In this case, the drying temperature can be defined in the temperature or drying step of the thermal medium supplied to the drying in the drying temperature of the reactor containing a heating medium and a polymer. If the drying temperature is low, the drying time long, so the process efficiency is lowered, a drying temperature in order to prevent this, 1201: preferably not less than In the case where the drying temperature is higher than necessary is dried excessively the surface of the hydrogel polymer subsequent process which may be the differentiation occurs more in the milling step, there are the physical properties of the final resin can be reduced, the drying temperature is 2501 to prevent this: it is preferably not more than.

At this time, the drying time in the drying step may be particularly, but not limited, in consideration of the physical properties of the resin and process efficiency, control of 20 minutes to 90 minutes at the drying temperature.

The drying may be done using a conventional medium, for example, can be performed through a method such as the hot air supplied to the pulverized hydrogel polymer, infrared irradiation, microwave irradiation, or UV irradiation.

In addition, such drying is preferable that the dry polymer is carried out so as to have a water content of from 0.1 to 10% by weight. That is, when the water content of the dried polymer is less than 0.1 wt% is not preferred because the decomposition (degradation) of the rise and cross-linked polymer of the manufacturing costs caused by excessive drying can take place, and, the water content of the dry polymer more than 10% by weight the dried polymer in the subsequent steps is attached to the case is not preferred because it be the way of the transfer path.

After the drying, it is possible to crush the dried polymer, may This allows the particle size and surface area of ​​the polymer can be adjusted to an appropriate range. The pulverization, the particle diameter of the pulverized polymer can be carried out so that from 150 to 850. The grain size of the well and be defined as the longest diameter of the respective polymer particles, the same applies hereinafter.

The roneun grinder available pin mill (pin mill), a hammer mill (hammer mill), screw mill (screw mill), a roll mill (roll mill), disc mill (disc mill), a jog mill (jog mill) such as conventional geotkki It can be used.

In addition, the high end is commercialized in order to manage the physical properties of the water absorbent resin, the method comprising: selectively classified into particles having a particle diameter of 150 to 850 in the polymer particles obtained through the pulverizing step can be further performed.

On the other hand, to prepare a base resin powder through to the above-described classification process are hanhue can be high and in the presence of a surface crosslinking agent, and heat-treating the base resin powder surface crosslinking the water absorbent resin particles. The surface crosslinking may be said to induce a crosslinking reaction to the surface of a base resin powder, such a surface modification layer on the surface the surface of the base resin powder from the cross-linking (surface cross-linked layer) is formed in the presence of a surface crosslinking agent.

More specifically, in the method for producing the other implementations described embodiment, the surface cross-linking agent and the comprises a liquid medium, and 20 to the surface tension at a temperature of 25 C is 25 to 50 mN / m, or from 30 to 47 mN / m surface crosslinking solution the heat treatment can be conducted by using the surface cross-linking.

In this way, according to the use of the surface cross-linking fluid having a relatively low surface tension, in spite of a relatively non-uniform in particle form (including multiple particles having a low aspect ratio), the surface cross-linkage proceeds uniformly, having an excellent degree of crosslinking and strength the surface cross-linked layer can be uniformly formed, and may be improved absorption capacity and absorption capacity under pressure than the liquid cylinder, etc. of the water absorbent resin. However, when the surface tension is too low, and can increase the rihaet of care, there is formed in the non-uniform cross-linked surface layer when using the surface cross-linking solution having a high surface tension,

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Absorption capacity against pressure properties such as absorption capacity and the liquid cylinder can be lowered.

As already described above, this in order to obtain a surface cross-linking solution having a specific surface tension, may be used in combination of two or more of each other an alkylene carbonate having 2 to 6 carbon atoms and having a different number of carbon atoms as the surface cross-linking agent.

In order to accomplish the above-mentioned surface tension is more effective, the surface cross-linking agent and surface cross-linking solution including the liquid medium is optionally a surfactant, the following formula 1 and formula 1, polycarboxylic acid-based copolymer or carbon atoms having a repeating unit represented by the and the like aliphatic alcohols of 6 or more may be further included. In this way, multiple types of use of the surface cross-linking agent, and optionally by additional components included in the surface cross-linking solution, the surface tension of the surface cross-linking solution is relatively high one embodiment is achieved with a lower specific range having the above-mentioned various physical properties of the absorbent the resin can be prepared:

[Formula 1-T

In Formula 1-3, and 1 七,

, II 2 and II 3 and are each independently hydrogen or an alkyl group having 1 to 6, 110 is an oxyalkylene group of a carbon number of 2 to 4, M 1 is hydrogen or a monovalent metal or non-metal ion, is -000 -, an alkylene dioxy group having 1-5 carbon atoms or an alkyloxy group having 1 to 5, and III is an integer from 1 to 100, 11 2019/117482 1 »(1 ^ 1 {2018/013917

An integer from 1 to 1000, I) is an integer from 1 to 150, or more above I) is 2-110 is repeated two or more - are the same or differ from each other.

In such a surface cross-linking step, the surface cross-linking agent, there is an alkylene carbonate having 2 to 6 carbon atoms may be used a plurality of types, suitable examples more thereof include ethylene carbonate, propylene carbonate, butylene carbonate, trimethylene carbonate, or glycerol carbonate, etc. It can be given.

At this time, the amount of the surface cross-linking agent is suitably can be adjusted, preferably, the base resin powder according to the kind and reaction conditions of the crosslinking agent 100 may be adjusted as part of 0.001 to 5 parts by weight relative to the weight section. When the too low amount of the surface cross-linking agent, a surface modification can not be achieved properly, the physical properties of the final resin can be lowered. Conversely an excess of the surface crosslinking agent is used because of the excessive surface cross-linking reaction is not preferable because the absorption capacity of the basic resin can be even reduced.

In addition, for control of the surface tension, the range of the surface cross-linking solution, the surface cross-linking solution there also can further comprise a surface active agent, the type of such surfactant is not particularly limited, a liquid medium contained in the pyopyeon crosslinking solution in consideration of the categories ,, it can be selected as appropriate from a nonionic surfactant, an anionic surfactant or a cationic surfactant. This allows can add control the surface tension of the surface cross-linking solution in the above-mentioned range.

And, in another example, the surface cross-linking solution may be further include a polycarboxylic acid type copolymer having a repeating unit represented by Formula 1 and Formula 1 is greater. The polycarboxylic acid-based copolymer is prepared by the method known such as Patent No. 1,684,649 No. and the like are apparent to those skilled in the art.

According to Sikkim those contained in the polycarboxylic acid type surface cross-linking solution of a copolymer in an amount of 0.001 to 5 parts by weight per 100 parts by weight of the base resin powder , the surface tension of the surface cross-linking solution may be added to the control by the above-mentioned range .

In addition, as another means for controlling the surface tension of the surface cross-linking solution, with a polar solvent such as water or an alcohol in a liquid medium in the surface cross-linking mixture, it may further contain an aliphatic alcohol having 6 or more.

According to one embodiment, it may be made of the first of C6 to C20 as the carbon number of 6 or more aliphatic alcohols, secondary, or tertiary alcohol for example, and preferably may be a primary alcohol of C6 to C16. More preferably stearyl El: it is not alcohol (stearyl alcohol), lauryl alcohol (lauryl alcohol), and cetyl alcohol can be used, but at least one member selected from the group consisting of (cetyl alcohol), limited.

The amount of the carbon number of 6 or more aliphatic alcohols are the above-mentioned pulverization polymer, that is, based on 100 parts by weight of a base resin powder, about 0.001 to about 2 parts by weight, or from about 0.01 to about 1 parts by weight, preferably from about 0.01 to about 1 the weight part, and more preferably may be from about 0.05 parts to about 0.8 parts by weight.

On the other hand, the surface crosslinking solution may further include with the components described above, as the liquid medium of water and / or a hydrophilic organic solvent (e.g., alcohol-based polar organic solvent such as methanol). At this time, the content of water and a hydrophilic organic solvent is leading to uniform dispersion of a surface cross-linking solution and also prevent the aggregation phenomena of the base resin powder and at the same time for 100 parts by weight of the object to the base resin powder for the optimization of the surface depth of penetration of the surface cross-linking agent It can be applied by adjusting the addition rate.

Also the above-described surface cross-linking solution in the method of adding the base resin powder, there is no particular limitation in its configuration. For example, surface cross-linking solution as a base resin powder were placed in the reaction tank mix and , method of surface cross-linking aekreul injection in the base resin powder, mixed and continuously supplied to a base resin powder and the surface cross-linking solution in the mixer being continuously operated at You can use the methods.

The surface cross-linking solution is 140 for the addition of a base resin powder ° C to 200 ° C, or 170 ° 5 to 60 minutes in the reaction up to a temperature of C to about 195 ° C, or 10 minutes to 50 minutes, or 20 minutes to for 45 minutes it may be carried out a surface crosslinking reaction. More specifically, the surface cross-linking step is 20 ° C to 130 ° C, or 40 ° and the temperature was raised to C to from the initial temperature of 120 ° C 10 min or more, or 10 minutes to 30 minutes, the reaction up to a temperature over the, by annealing by holding the maximum temperature for 5 minutes to 60 minutes it may be done.

These surface cross-linking process conditions (in particular, at elevated temperature reaction conditions and the maximum temperature

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The superabsorbent resin which suitably meet one embodiment the physical properties by the meeting of the reaction conditions) can be prepared more effectively.

Temperature raising means for the surface cross-linking reaction is not particularly limited, but. Supplying a heating medium, or can be heated to supply the heat source directly. At this time, using roneun The types of medium, but can use the w a fluid such as steam, hot air, hot oil, not limited to this, and the temperature of the heating medium supplied to consider the means, the rate of rise and temperature rise target temperature of the heating medium and it can be appropriately selected . On the other hand , as a heat source is directly supplied to the heating by electricity, but include a method of heating with a gas, it is not limited to the above example.

The super-absorbent resin obtained by the above production method is beam and SAT and maintained excellent absorption performance, such as pressure absorption capacity, than to meet and improved whole liquid, and absorption rate, and can meet one embodiment various physical properties, the diaper the equipotential saengjae, in particular, the content of the pulp decreases ultra-thin sanitary material, etc. can be used appropriately.

【Effects of the Invention】

Super-absorbent resin according to the present invention, yet can excellently maintain the basic ability to absorb, and can exhibit such improved absorption rate and the barrel-component, it can be preferably applied to the diaper such as sanitary material having a thinner thickness.

[Brief description of drawings]

Even in a high water-absorbent resin eunil 1 embodiment, and an electron micrograph showing an example of the aspect ratio defined and methods for measuring a water-absorbent resin particles.

[Mode for Carrying out the invention]

Below, it is presented to a preferred embodiment for better understanding of the invention. However, the practice of the following examples are intended only to illustrate the invention , not to limit the invention to these.

Example 1

Roneun apparatus for manufacturing a super-absorbent resin was used for continuous production apparatus consisting of a polymerization process, hydrogel milling step, drying step, pulverization step, the classification step, the surface cross-linking step, the cooling step, the classification step and the transporting step of connecting the respective steps .

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(Step 1)

Into the cross-linking agent to the acrylic acid 100 parts by weight of polyethylene glycol diacrylate (weight-average molecular weight: 500 to drink), and allyl meth by mixing methacrylate 0.4 parts by weight, 0.1 part by weight of sodium hydrogen carbonate as the foaming agent, sodium dodecyl sulfate as a surfactant 0.01 parts by weight of a photoinitiator 1¾ ¥ 2,4,6- 111 11 } ¾ »61120> 4) 1) 11051) 116 0 1 ^ (16 of 0.01 was prepared by mixing parts by weight of the monomer solution. Then, the monomer solution was continuously fed to the metering pump, while, at the same time to prepare a continuous line mixing to the monomer aqueous solution of 24 weight parts 160 weight% aqueous solution of sodium hydroxide. In addition, after continuous in-line mixing unit 4 wt% sodium persulfate aqueous solution 6 parts by weight, it was continuously fed to the continuous polymerization with the polymerizable groups on the belt having a dam on one plane at both ends. Then examines the 11 \ ^ to prepare a hydrogel.

(Step 2)

Hanhue the hydrogel with an average size cut such that about 300 _ hereinafter grinder (10 1 ! 1. In a multi comprising a plurality of holes having a diameter in the box having the perforated plate), which was triturated with each condition.

(Step 3)

Then, the additive was dried to a hydrogel grinding in step 2 can have the air volume transferred to the upper and lower dryer and flowing the hot air be at 180 d is the moisture content of the dried powder is less than or equal to about 2% and upward from the bottom for 15 minutes was to flow downward from the upper side again for 15 minutes and uniformly drying the hydrogel.

(Step 4)

Crushing the dried resin from step 3 to a mill and then classified to 150 to 850 ίM obtain a base resin of the size.

(Step 5)

Then, ethylene carbonate, 1 §, 1 eulmul 4 in propylene carbonate § the surface cross-linking solution was placed and mixed was prepared. The surface tension of the surface cross-linking solution was determined by ^ 4511/111.

About 100 for a base resin powder prepared as described in Step 4, the surface cross-linking solution 6 § by spraying, and stirred at room temperature for the surface on the base resin powder

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It was mixed so as to evenly distribution of the crosslinking solution. Then, into the surface cross-linking solution and the mixed powder on the surface of the base resin cross-linking reactor and proceed to the surface cross-linking reaction.

Within this surface cross-linking reactor, a base resin powder
was confirmed to be gradually raised from the initial temperature in the vicinity, in 30 minutes, 1901: was operated to reach the maximum temperature of the reaction. After reaching this reaction the maximum temperature, the grain size of the 15-minute incubation after the final manufacturing a super-absorbent resin sample was taken. The surface cross-linking step and then, ASTM classified to 150_ body standard network to 850 ssaen a standard! For a super-absorbent resin of example 1 has been prepared.

A base resin and high water-absorbent resin obtained by the above method to analyze the electron micrograph (see Fig. 1 and the like), each of the base resin powder and a high aspect ratio of the water-absorbent resin particles ( 3 / was calculated birul, the total base resin powder and the super-absorbent resin the aspect ratio of the particles is less than 0.5, the proportion of particles (% by number :) was measured measurement results, the base resin powder and the super-absorbent resin particles wherein an aspect ratio of less than 0.5, the proportion of particles was found to be about 10% by number.

Example 2

As a blowing agent was prepared, and is conducted super-absorbent resin of Example 2 in the same manner as in Example 1 except that 0.15 parts by weight of sodium hydrogen carbonate. By analyzing the base resin ./ super-absorbent resin obtained in this way with an electron microscope picture aspect ratio of the total base resin powder and the super-absorbent resin particles was measured less than 0.5, the proportion of particles (% by number). Measurement results, the base resin and the powder of the high water-absorbent resin particles, the aspect ratio is less than 0.5, the proportion of particles was found to be about 33% by number.

Example 3

And the water-absorbent resin is carried out and in Example 3 in the same manner as in Example 1 except that 0.2 parts by weight of sodium hydrogencarbonate was prepared as a blowing agent. By analyzing the base resin / super-absorbent resin obtained in this way with an electron microscope picture aspect ratio of the total base resin powder and the super-absorbent resin particles was measured less than 0.5, the proportion of particles (% by number). Measurement results, the base resin and the powder of the high water-absorbent resin particles, the aspect ratio is less than 0.5, the proportion of particles was found to be about 45% by number.

Surface cross-linking step after the paper was prepared and the absorption constant of the third embodiment has a grain size of the Example 1 proceeds in the same manner as 150 ssaen! _ To 850.

Example 4

Except that shares Polyoxyethylenesorbitan monopalmitate 0.02g as a lubricant in the surface cross-linking solution in the step 5 was prepared in Example 4 and a water-absorbent resin in the same manner as in Example 3.

Example 5

Godeup the water-based resin of Example 5 in the same manner as in Example 3 except that the hagoneun more aliphatic alcohols (mono stearyl alcohol) 0.3g as a lubricant in the surface cross-linking solution was prepared in 5 steps.

Example 6

Polyester obtained by the surface cross-linking to manufacture lubricants Patent No. 1,684,649 favor of liquid Example 1 gwadong a method in step 5, a carboxylic acid-based copolymer O.lg Example 1, and the super-absorbent of Example 6 in the same way except that the add to prepare a resin.

Example 7

And was prepared in a super-absorbent resin of Example 7 in the same manner as in Example 3 except for the use of the surface cross-linked trimethylene carbonate 1 g of the liquid, the surface cross-linking is mixed into the propylene carbonate 1 g eulmul 4 g in step 5 .

Comparative Example 1

As a blowing agent in step 1 was prepared in the base resin of Comparative Example 1 in the same manner as in Example 1 except that no hagoneun with sodium hydrogen carbonate.

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By analyzing the base resin obtained in this way with an electron microscope picture aspect ratio of the total base resin powder were measured less than 0.5, the proportion of particles (% by number). Measurements, of the base resin powder, an aspect ratio of less than 0.5, the proportion of particles was found to be about 5% by number.

Comparative Example 2

Ethylene carbonate. 1 is a base resin powder 100 parts by weight of the prepared water 4 § hagoneun Comparative Example 1 and the same, except for using a surface cross-linked liquid 5 for mixing into a ¾ to prepare a super-absorbent resin of Comparative Example with up two. The surface tension of the surface cross-linking solution was 51 1! / 111 was measured.

Comparative Example 3

The ethylene carbonate is 1 to 4 The water-based 100 parts by weight of the resin powder produced § mixed into a surface cross-linking solution 5 § a superabsorbent resin in the same manner as in Comparative Example 1 except for using hagoneun Example 3 was prepared.

Comparative Example 4

To 100 parts by weight of a base resin powder Preparation 1 Ethylene carbonate § eulmul 4 ¾ page into - · ¾ sum-a-table-side 7上· les 5_ § to-use and _ _ a ¾_ euljen other half always Example 3 a super-absorbent resin of Comparative example 4 was prepared in the same manner.

Comparative Example 5

According to the method described for preparation of heading Korea Laid-Open Patent Publication No. 2015-0132035 it was performed to manufacture and drying of the hydrogel polymer. Then, to prepare a super-absorbent resin of Comparative Example 5 to prepare a base resin and proceeds to the surface cross-linking according to the method described in the above heading 2015-0132035 Korea Laid-Open Patent Publication 1 for example.

Experimental Example

Examples and Comparative physical properties of each super-absorbent resin prepared in Examples and Preparation

The various physical properties of the process were measured and evaluated in the following manner.

(1) a base resin powder and a high aspect ratio and the measurement of particle size distribution of the water absorbent resin particles

An overall through an electron microscope, such as 1 to calculate the shortest diameter (a) and the longest diameter (bieul of each powder / particles therefrom were measured aspect ratio of each of the powder / particles, the resulting yarn in each example / comparative example the powder / particle the aspect ratio was calculated of the number proportion (% by number) of 0.5 is less than the powder / particle.

(2) centrifuging beam SAT (CRC, Centrifuge Retention Capacity)

European Nonwoven Industry Association (European Disposables and Nonwovens Association, EDANA) standard EDANA was measured centrifugation beam SAT (CRC) due to no load Heavy absorption magnification according to WSP 241.3. Superabsorbent Polymer W 0 ( a g, about 0.2g) Nonwoven placed uniformly on the envelope of the sealing (seal) then was submerged in saline solution of sodium chloride solution of 0.9 weight% at room temperature. Using a centrifugal separator the bag after 30 minutes and the mass W of the bag for 3 minutes after removing moisture with 250G 2 ( decided i.e. the g). Further, to measure the time of the mass in the same manner hanhue gotop without using the water-based resin. In this way use of the respective mass obtained by the following equation 1 to calculate the CRC (g / g) it was confirmed beam SAT.

[Equation 1]

CRC (g / g) = { [W 2 (g) - W ! (g) - Wo (g) ] AV 0 (g)}

(3) a pressure drop SAT (Absorbing under Pressure, AUP)

Was jeukjeong to: (Absorbency under Pressure AUP) of Examples and Comparative Examples that, the European Association for the nonwoven industry in the water-absorbent resin according to the process of the absorption capacity under pressure (European Disposables and Nonwovens Association) standard EDANA WSP 242.3.

First, the bottom of the cylinder having an inner diameter of 60 mm plastic was fitted to a stainless steel 400 mesh wire net. Under a relative humidity of 45% and a temperature of 23 ± 2 ° C in the iron mesh Examples 1-6 and Comparative Examples 1-4 obtained by the resin W 0 ( to spray uniformly g, 0.90 g)

On top of 4.83 kPa (0.7 psi) the piston (piston) that can more uniformly impart load is no gap between the inner wall and the outer diameter is slightly smaller than the cylinder 60 mm, it was not disturbed the upper and lower movement. The weight W of the device 3 ( to measure the g).

With a glass filter having a thickness of 5 mm on the inside of the Petro-dish with a diameter of 150 mm in diameter 125 mm, a saline solution consisting of 0.90 wt% sodium chloride it was adjusted to the same level as the upper surface of the glass filter. Carrying the measuring device on a glass filter, the liquid was absorbed under the load for 1 hour. After 1 hour, lift the measuring device, the weight w 4 ( was the jeukjeong g).

In this way use of the respective mass obtained by the following equation 2 to calculate the AUP (g / g) confirmed that the pressure absorbing ability.

[Formula 2]

AUP (g / g) [W 4 ( g) - W 3 ( g)] / W 0 ( g)

In the formula 2,

W 0 ( a g) Initial weight (g) of water absorbent resin neungo,

W 3 ( g) and neungo total weight of the device being capable of imparting a load to the weight and the water-based resin of the top gotop water-based resin,

W 4 ( g) is the weight of chunghap and apparatus that can impart a load on the superabsorbent polymer weight of one hour and the water absorbent resin after the high absorption of saline solution to the water-absorbent resin, while under load (0.7 psi).

(4) flow induced physiological saline (SFC; saline flow conductivity)

United States was measured and calculated according to the method disclosed in Patent No. 5,562,646 the arc column 54 to column 59.

(5) 30 superabsorbent speed

30 seconds absorption speed, and the porosity can be measured while swelling under 0.3psi pressure condition by a super-absorbent resin of from about 0.16g to a physiological saline flows through the mesh of the cylindrical cylinder bottom. In real time and to rheometers measure the height change of the upper plate, jeukjeong and calculating the 30 seconds dopsu speed through divided by the time (30 seconds) topsu a top plate height at 30 seconds according to the volume expansion of the water-absorbent resin can. Further, the void ratio is the high time would have been the swelling of the water-absorbent resin completed, the total volume of the cylinder (end absorption height * calculating a cylindrical cylinder lower area), subtracting a physiological saline absorption of the superabsorbent resin measured at the value to the water content meter It can be calculated by the method.

(6) Surface cross-linking solution and the high surface tension of the water-absorbent resin

All procedure was conducted in a constant-temperature hangseupsil (temperature 23 ± 0.5 ° C, relative humidity of 45 ± 0.5%).

First, the surface tension of the surface cross-linking solution was measured using a surface tension-to-extruding such a surface cross-linking solution with a pipette and transferred into another clean cup that is regular (surface tensionmeter Kruss Kl l / KlOO).

Next, the high surface tension of the water-absorbent resin is contained a saline solution consisting of 150g of 0.9 weight% sodium chloride in 250mL beaker was immediately magnetic stirring. Superabsorbent Polymer l.Og the swelling stop stirring after stirring for 3 minutes into the stirring solution and the water absorbent resin is allowed to stand for at least 15 minutes so as to sink to the bottom.

Then the supernatant was extracted with a (right bottom of the surface of the solution), the pipette is measured by using a surface tension that is regular (surface tensionmeter Kruss K11 / K100) was transferred to another clean cup.

To the respective physical properties of the measurement carried out using the above Examples 1 to 7 and Comparative Examples 1 to 5 are shown collectively in Table 1.

TABLE 1

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Referring to Table 1, Examples 1 to 7 satisfy the predetermined particle size distribution, and 35 (_10_ 7 11 3 3 / it was confirmed that excellent tube-component refers to the as defined above. The Examples 1 to 7 are absorbed as well as excellent basic absorption performance, which is defined as dodeung, yet excellent in the liquid cylinder, the optimized particle distribution was found to be also excellent absorption rate as defined by the superabsorbent 30 speed.

In this comparison, Comparison Examples 1 to 5 when compared to example neunsil, barrel-component or one or more of rate of absorption was found to be poor.

[Claims]
1. The

A base resin powder including a first cross-linked polymers of water soluble ethylenically unsaturated monomer having at least partially neutralized acid; and

A super-absorbent resin to the first cross-linked polymer is formed on the base resin powder, a cross-linked layer includes a surface including a second cross-linked polymer cross-linking a surface cross-linking agent is added to the medium,

The super-absorbent resin is high and an aspect ratio of less than 0.5 as defined by the shortest diameter / the longest diameter of each of the super-absorbent resin particles including a water-absorbent resin particles with 10% by number or more,

Inductive flow of physiological saline (0.685% by weight aqueous solution of sodium chloride) 10 7 0 11 3 ·%) 30 (10 7 0 11 3 5 ^) than godeup water-based resin.

[Claim 2]

To the claim, in an anti-absorbency of 46 to 63 represented by the formula 1 gotop water-based resin:

[Equation 1]

Absorbency = 犯 + four 正

In the formula 1,

比 is the high denotes a beam SAT centrifugation for 30 min on saline (0.9 wt% aqueous sodium chloride solution) of a water-absorbent resin,

1 shows 正 represents the high absorption capacity under pressure for 1 hour at 0 to physiological saline (0.9 wt% aqueous sodium chloride solution) of a water-absorbent resin.

[Claim 3]

The method of claim 2, wherein the first (: 25 to 35 § ingot absorbing resin.

[Claim 4]

The method of claim 2 wherein the
super-absorbent resin.

[5.]

The method of claim 1, wherein a 30-second deupsu rate for physiological saline under pressure of 0.3 psi 1.5mm / min or more godeup water-based resin.

[Claim 6]

The method of claim 1, wherein the surface tension (surface tension) of super-absorbent resin is 60 to 75 mN / m.

[Claim 7]

The method of claim 1, wherein the surface cross-linking agent having a carbon number having a different number of carbon atoms

Godop water-based resin containing two or more kinds of the alkylene carbonate in a 2 to 6.

[8.]

The method of claim 1, wherein the water-soluble ethylenically unsaturated monomer is acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-1-acryloyl ethane sulfonic acid, 2-1 ethanesulfonic acid, methacrylonitrile, 2- (meth) acrylamide-2-eulyi-ionic monomer and a salt thereof of methylpropanesulfonic acid (meth) acid, or 2-acryloyl; (Meth) acrylamide, N- substituted (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxy polyethylene glycol (meth) acrylate or polyethylene glycol ( meth) non-ionic hydrophilic monomers containing acrylate; And (N, N) - dimethyl amino propyl (meth) amino group-containing unsaturated monomers and their quaternary products of acrylamide-dimethylaminoethyl (meth) acrylate or (N, N); one or ahsang selected from the group consisting of superabsorbent polymer containing.

[Claim 9]

Further comprising: in the presence of a blowing agent, and an internal crosslinking agent, to form a hydrogel polymer comprising a first cross-linked polymer by polymerizing a water-soluble cross-linked ethylenically unsaturated monomer having at least partially neutralized acid;

The hydrogel polymer of the gel crushing, followed by drying, crushing and classification, each of the base

Further comprising: an aspect ratio, defined as the shortest diameter / the longest diameter of the resin powder to form a base resin containing 0.5 less than the base resin powder with at least 10% by number; and the surface cross-linking agent and comprises a liquid medium, and from 20 to 25 ° the temperature of the C in the presence of the surface cross-linking the liquid surface tension of 25 to 50 mN / m in a method of manufacturing a superabsorbent polymer comprising the step of surface crosslinking by heating the base resin.

[10.]

The method of claim 9, wherein the internal cross-linking agent comprises a poly (meth) acrylate-based first internal crosslinking agent, and allyl (meth) acrylate-based second internal cross-linking agent of a polyol,

The first and the total content of the second internal cross-linking agent is a process for producing a water absorbent resin and is in an amount of 0.01 part by weight to 2 parts by weight based on 100 parts by weight of the monomer composition containing the monomer and internal crosslinking agent.

[11.]

10. The method of claim 9, wherein the foaming agent is sodium bicarbonate (sodium bicarbonate), sodium carbonate (sodium carbonate), potassium bicarbonate (potassium bicarbonate), potassium carbonate (potassium carbonate), calcium bicarbonate (calcium bicarbonate), calcium carbonate ( calcium bicarbonate), magnesium bicarbonate (method for producing a superabsorbent polymer containing at least one selected from the group consisting of magnesiumbicarbonate) and magnesium carbonate (magnesium carbonate).

[12.]

10. The method of claim 9, wherein the surface cross-linking agent having a carbon number having a different number of carbon atoms

And process for producing a water absorbent resin containing two or more kinds of the alkylene carbonate in a 2 to 6.

[13.]

The method of claim 12 wherein the surface crosslinking solution further comprises a surfactant

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The method of superabsorbent polymer.

[14.]

The method of claim 12, wherein the surface cross-linking solution is to method of manufacturing a super-absorbent resin, which further comprises a polycarboxylic acid type copolymer having a repeating unit represented by the formula (I) and the formula 1:

[Chemical Formula 1 Li

［

In the formula 1 e and 1,

II 1 , and ^ are each independently hydrogen or an alkyl group having 1 to 6, 110 is an oxyalkylene group of a carbon number of 2 to 4, M 1 is hydrogen or a monovalent metal or non-metal ion, X is -000 -, an alkylene dioxy group having 1-5 carbon atoms alkyl group or a C 1 -C 5, and III is an integer from 1 to 100, and 11 is an integer from 1 to 1000, is an integer from 1 to 150, the I ) -110 is repeated two or more not less than two - is the same as or differ from each other.

[15.]

13. The method of claim 12, wherein the liquid medium of the surface cross-linking solution process for producing a superabsorbent resin further comprises an aliphatic alcohol having 6 or more.

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[16.]

At a temperature of 140 ° to 200 X 0 over a period of 10 minutes to 30 minutes: the temperature was raised to a maximum temperature of, and method for producing a superabsorbent polymer which is conducted by the maximum temperature of heat treatment by keeping it for 5 minutes to 60 minutes.