WO2017111205A1 - Method for production of super-absorbent resin - Google Patents

Method for production of super-absorbent resin Download PDF

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Publication number
WO2017111205A1
WO2017111205A1 PCT/KR2016/002725 KR2016002725W WO2017111205A1 WO 2017111205 A1 WO2017111205 A1 WO 2017111205A1 KR 2016002725 W KR2016002725 W KR 2016002725W WO 2017111205 A1 WO2017111205 A1 WO 2017111205A1
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Prior art keywords
polymer
method
super absorbent
surface crosslinking
water
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PCT/KR2016/002725
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French (fr)
Korean (ko)
Inventor
김주은
김기철
박세열
김기현
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주식회사 엘지화학
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Priority to KR20150184917 priority Critical
Priority to KR10-2015-0184917 priority
Priority to KR1020160029847A priority patent/KR101857702B1/en
Priority to KR10-2016-0029847 priority
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority claimed from EP16879073.1A external-priority patent/EP3321307A4/en
Publication of WO2017111205A1 publication Critical patent/WO2017111205A1/en

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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00Processes of polymerisation
    • C08F2/44Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00Processes of polymerisation
    • C08F2/46Polymerisation initiated by wave energy or particle radiation
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08FMACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical or a salt, anhydride, ester, amide, imide or nitrile thereof
    • C08F20/02Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/04Acids, Metal salts or ammonium salts thereof
    • C08F20/06Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G
    • C08J3/00Processes of treating or compounding macromolecular substances
    • C08J3/02Making solutions, dispersions or lattices by other methods than by solution, emulsion or suspension polymerisation techniques
    • C08J3/03Making solutions, dispersions or lattices by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media
    • C08J3/075Macromolecular gels
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G
    • C08J3/00Processes of treating or compounding macromolecular substances
    • C08J3/24Crosslinking, e.g. vulcanising, of macromolecules
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08KUse of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00Use of inorganic substances as compounding ingredients
    • C08K3/34Silicon-containing compounds

Abstract

The present invention relates to a method for production of a super-absorbent resin. The preparation method of the present invention allows the surface penetration depth of a surface cross-linking agent to be adequately controlled, and also allows a super-absorbent resin having excellent physical properties to be produced through uniform surface cross-linking. Accordingly, it is possible to provide a super-absorbent resin having improved absorption properties without lowering the pressure absorption ability.

Description

 【Specification】

 [Name of invention]

 Manufacturing Method of Super Absorbent Resin [Technical Field]

 Cross citation with related application (s)

 This application claims the benefit of priority based on Korean Patent Application No. 10-2015-0184917 dated December 23, 2015 and Korean Patent Application No. 10-2015-0029847 dated March 11, 2016, All content disclosed in the literature is included as a part of this specification.

 The present invention relates to a method for producing a super absorbent polymer. More specifically, the present invention relates to a method for producing a super absorbent polymer having improved water absorption characteristics without deterioration in water holding capacity and pressure absorbing capacity. Background technology

 Super Absorbent Polymer (SAP) is a synthetic polymer material capable of absorbing water of 500 to 1,000 times its own weight.As a developer, super absorbent material (AMG) and absorbent gel (AGM) They are named differently. Such super absorbent polymers have been put into practical use as physiological tools, and are currently used in sanitary products such as paper diapers for children, horticultural soil repair agents, civil engineering, building index materials, seedling sheets, food preservation crabs, and It is widely used as a material for steaming.

As a method for producing such a super absorbent polymer, a method by reverse phase suspension polymerization or a method by aqueous solution polymerization is known. Reverse phase suspension polymerization is disclosed in, for example, Japanese Patent Laid-Open Nos. 56-161408, 57-158209, and 57-198714. As a method of aqueous solution polymerization, a thermal polymerization method in which a hydrous gel polymer is broken and polymerized in a kneader having a plurality of shafts, and photopolymerization which simultaneously performs polymerization and drying by irradiating ultraviolet rays or the like on a belt with a high concentration of aqueous solution Methods and the like are known. On the other hand, the hydrous gel polymer obtained through the polymerization reaction as described above is generally subjected to a step of selectively crosslinking the surface of the polymer in order to have a desired absorption capacity and pressure absorption capacity after the grinding process. In such surface crosslinking, it is necessary to control the penetration depth of the surface agent, and for this purpose, it is common to control the penetration depth of the surface crosslinker using alcohol and water. However, when alcohol is used to control the penetration depth of the crosslinking agent, a large amount of alcohol is consumed, which is disadvantageous in terms of cost : an additional drying treatment is required.

 Therefore, in order to solve the above method, conventionally, methods of minimizing the amount of alcohol or using no alcohol have been presented. However, when the amount of alcohol used is excessively lowered, water is excessively absorbed into the polymer and there is a problem that efficient crosslinking is difficult due to agglomeration of the gel.

[Content of invention]

 [Problem to solve]

 According to the present invention, by performing a surface crosslinking reaction using a surface crosslinking agent that satisfies specific conditions, the surface crosslinking agent can further improve the physical properties of the final product by adjusting the penetration depth. It is to provide a method for producing a super absorbent polymer.

[Measures of problem]

 According to an aspect of the present invention for solving the above problems, the step of thermally polymerizing or photopolymerizing a monomer composition comprising a water-soluble ethylenically unsaturated monomer and a polymerization initiator to form a hydrogel polymer; Drying the hydrogel polymer;

 Pulverizing the dried polymer; And

It provides a superabsorbent polymer and a manufacturing method comprising the step of performing a surface crosslinking reaction by mixing the ground polymer and a surface crosslinking agent comprising a hydrophobic alcohol. 【Effects of the Invention】

 In the method for preparing a super absorbent polymer according to the present invention, the surface penetration depth of the surface crosslinking agent can be appropriately controlled by using a hydrophobic alcohol having 4 or more carbon atoms instead of the hydrophilic alcohol generally used as the surface crosslinking agent. Through the superabsorbent polymer having excellent physical properties can be prepared.

 Accordingly, product properties can be further improved, and in particular, it is possible to provide a superabsorbent polymer having improved absorption characteristics without deteriorating the pressure absorption capacity. [Specific contents to carry out invention]

 The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to be limiting of the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. As used herein, the terms "comprise", "comprise" or "have" are intended to indicate that there is a feature, step, component, or combination thereof that is practiced, and that one or more other features or steps, It is to be understood that the present invention does not exclude the possibility of adding or presenting elements, or a combination thereof.

 As the invention allows for various changes and numerous modifications, particular embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to a specific disclosed form, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

Hereinafter, a method for preparing a super absorbent polymer according to a specific embodiment of the present invention will be described in detail. Method for producing a super absorbent polymer of the present invention comprises the steps of thermally polymerizing or photopolymerizing a monomer composition comprising a water-soluble ethylenically unsaturated monomer and a polymerization initiator to form a hydrogel polymer; Drying the hydrogel polymer; Pulverizing the dried polymer; And pulverized polymer, hydrophobic Mixing a surface crosslinking agent comprising an alcohol to perform a surface crosslinking reaction.

 For reference, in the specification of the present invention, "polymer" or "polymer" means that the water-soluble ethylenically unsaturated monomer is in a polymerized state, and may cover all water content ranges or particle size ranges. Among the above polymers, a polymer having a water content (water content) of about 40% by weight or more after being dried before polymerization may be referred to as a hydrous gel polymer.

 In addition, "base resin" or "base resin powder" means that the polymer is dried and ground to form a powder.

 "Superabsorbent resin" also means the polymer or the base resin itself depending on the context, or further processes for the polymer or the base resin, for example surface crosslinking, fine powder reassembly, drying, grinding, classification, etc. It is used to cover everything that has been made suitable for commercialization through.

 In the manufacturing method of the present invention according to the embodiment described above, the step of forming a hydrogel polymer, the drying of the hydrogel polymer, and the step of pulverizing the dried polymer is in the art for preparing a super absorbent polymer It can be carried out by the steps and methods commonly used in the art.

 First, specifically, the monomer composition which is a raw material of the super absorbent polymer includes a water-soluble ethylenically unsaturated monomer and a polymerization initiator.

 As the water-soluble ethylene-based unsaturated monomer, as long as it is a monomer commonly used in the production of superabsorbent polymers, it may be used without limitation in the constitution. In general, any one or more selected from the group consisting of anionic monomers and salts thereof, nonionic hydrophilic-containing monomers, amino group-containing unsaturated monomers and quaternized compounds thereof can be used.

Specifically, acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2- (meth) acryloylpropanesulfonic acid, or 2 Anionic monomers of (meth) acrylamide-2-methyl propane sulfonic acid and salts thereof; (Meth) acrylamide, N-substituted (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, Nonionic hydrophilic-containing monomers of methypolyethylene glycol (meth) acrylate or polyethylene glycol (meth) acrylate; And amino group-containing unsaturated monomers of (N, N) -dimethylaminoethyl (meth) acrylate or (N, N) 'dimethylaminopropyl (meth) acrylamide and quaternized compounds thereof. Can be used.

 More preferably, an alkali metal salt such as acrylic acid or a salt thereof, for example acrylic acid or a sodium salt thereof can be used, and the use of such a monomer makes it possible to prepare a super absorbent polymer having better physical properties. When the alkali metal salt of acrylic acid is used as a monomer, acrylic acid may be neutralized with a basic compound such as caustic soda (NaOH). At this time, the degree of neutralization of the water-soluble ethylenically unsaturated monomer may be adjusted to about 50 to about 95% or about 70 to about 85%, to provide a superabsorbent polymer having excellent water retention without fear of precipitation during neutralization within this range. can do.

The concentration of the water-soluble ethylenically unsaturated monomer, in which the subject from about 20 to about 60 weight 0/0, preferably from about 40 to about 50 increase% of the monomer composition containing a source material and a solvent of the water-absorbent resin, and In consideration of the polymerization time, the reaction conditions and the like, the concentration may be appropriate. However, when the concentration of the monomer is too low, the yield of the superabsorbent polymer may be low and there may be a problem in economics. On the contrary, when the concentration is too high, some of the monomer may be precipitated or the grinding efficiency of the polymerized hydrogel polymer may be low. Etc. may cause problems in the process and may decrease the physical properties of the super absorbent polymer. The polymerization initiator used in the polymerization in the method for producing a super absorbent polymer of the present invention is not particularly limited as long as it is generally used for producing the 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 such as ultraviolet irradiation, and a certain amount of heat is generated in accordance with the progress of the polymerization reaction, which is an exothermic reaction, it may further include a thermal polymerization initiator. 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.

Specifically, one or more selected from the group consisting of persulfate initiators, azo initiators, hydrogen peroxide, and ascorbic acid may be used as the thermal polymerization initiator. Specifically, examples of persulfate-based initiators include sodium persulfate (Na 2 S 2 0 8 ), potassium persulfate (K 2 S 2 0 8 ), ammonium persulfate (NH 4 ) 2 S 2 0 8 ), and examples of the azo (Azo) initiator include 2, 2-azobis- (2-amidinopropane) dihydrochloride (2, 2- azobis (2-amidinopropane) dihydrochloride), 2 2,2-azobis- (N, N-dimethylene) isobutyramidine dihydrochloride), 2-azobis- (N, N-dimethylene) isobutyramidine dihydrochloride

(Carbamoyl azo) isobutyronitrile ( 2- (carbamoylazo) isobutylonitril), 2, 2- azobis [2- (2-imidazoline-2-yl) propane] dihydrochloride (2,2-azobis [ 2- (2- imidazolin-2-yl ) propane] dihydrochloride), 4, 4 - azobis- (4-cyano-ballet rigs acid) (4, 4- azobis- (4 -cyanovaleric acid) , or the like) have. A wider variety of thermal initiators are well specified in the Odian book "Principle of Polymerization (Wiley, 1981)", p203, and are not limited to the examples 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 the thermal polymerization initiator is too low, additional thermal polymerization hardly occurs, and thus the effect of the addition of the thermal polymerization initiator may be insignificant. When the concentration of the thermal polymerization initiator is too high, the molecular weight of the superabsorbent polymer may be low and the physical properties may be uneven. have.

Examples of the photopolymerization initiator include benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, benzyl dimethyl ketal, and acyl. At least one selected from the group consisting of acyl phosphine and alpha -aminoketone may be used. On the other hand, as an embodiment of acylphosphine, commercially available lucirin TPO, that is, 2,4,6-trimethyl- benzoyl-trimethyl phosphine oxide (2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide) can be used. A wider variety of photoinitiators is well described in Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007) pi 15, but is not limited to the examples described above.

The photopolymerization initiator may be included in a concentration of about 0.005 to about 1.0 weight 0/0 with respect to the monomer composition. If the concentration of the photopolymerization initiator is too low, the polymerization rate may be slow. If 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.

 According to an embodiment of the present invention, the monomer composition may further include an internal crosslinking agent as a raw material of the super absorbent polymer. The internal crosslinking agent may include at least one functional group capable of reacting with the water-soluble substituent of the water-soluble ethylenically unsaturated monomer and at least one ethylenically unsaturated group; Alternatively, a crosslinking agent having two or more water-soluble substituents and / or functional groups capable of reacting with the water-soluble substituents formed by hydrolysis of the monomers may be used.

 Specific examples of the internal crosslinking agent include bisacrylamide having 8 to 12 carbon atoms, bismethacrylamide, poly (meth) acrylate having 2 to 10 carbon atoms, poly (meth) allyl ether having 2 to 10 carbon atoms, and the like. More specifically, Ν, Ν'- methylenebis (meth) acrylate, ethyleneoxy (meth) acrylate, polyethyleneoxy (meth) acrylate, propyleneoxy (meth) acrylate, glycerol diacrylate , Glycerin triacrylate, trimethol triacrylate, triallylamine, triarylcyanurate, triallyl isocyanate, polyethylene glycol, diethylene glycol and propylene glycol may be used. Such an internal crosslinking agent may be included in a concentration of about 0.001 to about 2.0 wt% based on the monomer composition to crosslink the polymerized polymer.

In the production method of the present invention, the monomer composition of the super absorbent polymer may be prepared by thickener, plasticizer, preservative stabilizer, antioxidant, etc. It may further include an additive.

 Raw materials such as the above-mentioned water-soluble ethylenically unsaturated monomers, 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-butanedi , 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 ethyl ether, toluene, xylene, butyrolactone, carbye can be used in combination of 1 or more types chosen from methyl cellosolve acetate, N, N-dimethylacetamide, etc.

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

 On the other hand, the method of preparing a hydrogel polymer by thermally polymerizing or photopolymerizing such a monomer composition is not particularly limited as long as it is a commonly used polymerization method. 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 semi-unggi machine having a stirring shaft 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, the hydrous gel polymer obtained by thermal polymerization by supplying hot air or by heating the reactor to a reactor such as a kneader having a stirring shaft as described above, is discharged to the reactor outlet according to the shape of the stirring shaft provided in the reactor. The gel polymer may be in the form of several centimeters to several millimeters. Specifically, the size of the water-containing gel polymer obtained may vary depending on the concentration and the injection speed of the monomer composition to be injected, the water-containing gel polymer having a particle size of 2 to 50 mm can be obtained.

In addition, the conveyor belt is movable as described above When the photopolymerization is carried out in the counterunggi, the form of the polymer usually obtained may be a hydrous gel polymer on a sheet having the 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 usually preferable to supply the monomer composition so that a polymer on the sheet having a thickness of about 0.5 to about 5 cm can be obtained. In the case of 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 thickness of the polymer on the sheet exceeds 5 cm, the polymerization reaction does not occur evenly over the entire thickness. You may not.

 On the other hand, the water content of the thermally polymerized or photopolymerized hydrogel polymer is

40 to 80% by weight. Throughout this specification, "water content" means the weight of the water-containing gel polymer subtracted from the weight of the dried polymer by the content of moisture to account for the total weight of the water-containing gel polymer. Specifically, it is defined as a value calculated by measuring the weight loss due to moisture evaporation in the polymer in the process of raising the temperature of the polymer through infrared heating and drying. At this time, the drying condition is to increase the temperature to 180 ° C at room temperature and then maintained at 180 ° C. The total drying time is set to 20 minutes, including 5 minutes of the temperature rise step, the moisture content is measured.

 Next, the hydrous gel polymer obtained is dried. At this time, if necessary, in order to increase the efficiency of the drying step, the rough grinding step before drying may be further roughened.

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 mill (cutter mill), the one selected disk grinder in the crushing machine the group consisting of (disc mill), a piece crusher (Shred crasher), crusher (crusher), 'chopper (chopper) and source plate type cutter (disc cutter) It may include, but is not limited to the above-described example. At this time, the grinding step may be pulverized so that the particle size of the hydrogel polymer is about 2 to about 10mm.

Grinding to a particle diameter of less than 2 mm is a high It is not technically easy due to the water content, and may also appear to agglomerate with each other among the ground particles. On the other hand, in the case where the particle size is pulverized more than 10mm, the effect of increasing the efficiency of the subsequent drying step is insignificant.

The pulverized or black hydrous polymer immediately after polymerization is subjected to a drying step. Preferably, the drying temperature of the drying step may be 150 ° C to 250 ° C. "Drying temperature" throughout this specification may be defined as the temperature of the heating reactor, including the heating medium and the polymer in the drying process, or the temperature of the heating medium supplied for drying.

If the drying temperature is less than 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 is higher than 250 ° C, only the polymer surface is dried excessively. Fine powder may occur in the grinding step, and there is a fear that the physical properties of the superabsorbent polymer to be finally formed decrease. Preferably the drying may be carried out at a temperature of 150 ° C to 200 ° C, more preferably at a temperature of 160 ° C to 180 ° C. On the other hand, the drying time is not limited to the configuration, but in consideration of the process efficiency, etc., it may proceed for 20 to 90 minutes.

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

 The dried polymer obtained through this drying step is subjected to a grinding step.

 The polymer powder obtained after the final grinding step may have a weight average particle diameter of 150 to 850. The grinder used to grind to such a weight average particle diameter is specifically a pin mill, a hammer mill, a screw mill, a mill, a disc mill. Or a jog mill (jog mill) and the like can be used, but the present invention is not limited to the above examples.

And, in order to manage the physical properties of the super absorbent polymer powder to be finalized after such a grinding step, the polymer powder obtained after grinding according to the particle size There may be a separate process of classification. Preferably, the polymer having a particle size of about 150 to about 850 11 may be classified so that the surface crosslinking reaction step may be performed only on the polymer powder having such a particle size.

 Next, a surface crosslinking reaction is performed by adding a surface crosslinking agent to the ground polymer.

 Surface crosslinking is the step of increasing the crosslink density near the polymer particle surface with respect to the crosslink density inside the particles. Generally, the surface crosslinker is applied to the surface of the polymer particles. Thus, this reaction occurs on the surface of the polymer particles, which improves the crosslinkability on the surface of the particles without substantially affecting the interior of the particles. The surface crosslinked polymer particles thus have a higher degree of crosslinking near the surface than inside.

 In the superabsorbent polymer production method of the present invention, surface crosslinking reaction is performed using a surface crosslinking agent containing a hydrophobic alcohol.

 According to one embodiment of the invention, the hydrophobic alcohol may be one or more selected from the group consisting of polyhydric alcohol (alcohol) having 4 or more carbon atoms. More specifically, a polyhydric alcohol having 4 to 10 carbon atoms, preferably 4 to 7 carbon atoms, and including a branched alkyl group, preferably 2,2-dimethyl-1,3- Propanedi (2,2 'Dimethyl-1,3-propanediol) can be used.

Although a method of using alcohols as the surface crosslinking agent is known, a hydrophilic alcohol such as alcohol having 3 or less carbon atoms such as 1,3-propanediol (1,3-PDO) has been used. However, when the hydrophilic alcohol is used as the surface crosslinking agent, as the reaction time increases, the degree of penetration of the surface crosslinking agent is too deep and crosslinking tends to proceed to the inside of the polymer. If the crosslinking reaction proceeds inside the polymer, the crosslinking density is increased, and thus the water holding capacity (CRC) and the pressure absorbing capacity (AUL) are reduced, resulting in a decrease in physical properties of the final product. On the other hand, in order to prevent the surface crosslinking reaction time is shortened, or there is also a method of lowering the reaction silver, in this case there is a risk that the surface crosslinking does not occur. In other words, using a hydrophilic surface crosslinking agent, the penetration depth of the surface crosslinking agent There was a problem that was difficult to adjust.

 On the other hand, in the superabsorbent polymer production method of the present invention by using a hydrophobic alcohol as a surface crosslinking agent solved this problem. When the surface crosslinking reaction is performed by adding hydrophobic alcohol to the polymer, it is difficult to penetrate into the polymer due to the hydrophobic property, so that the crosslinking reaction occurs only on the surface. Therefore, even if the crosslinking reaction time increases, crosslinking inside the polymer does not easily occur, and a crosslinking region is formed only on the polymer surface, and the water holding capacity and pressure absorbing ability of the base resin can be maintained.

 The hydrophobic alcohol content may be used in an amount of about 0.01 to about 10 parts by weight, preferably about 0.01 to about 5 parts by weight, and more preferably about 0.01 to about 1 part by weight, based on 100 parts by weight of the polymer.

 When the content of the hydrophobic alcohol is too small, the surface crosslinking reaction hardly occurs, and if it contains too much, deterioration of absorption capacity and physical properties may occur due to the excessive surface crosslinking reaction.

 According to an embodiment of the present invention, the surface crosslinked semi-finished silica (silica) or clay (clay) may further include. Since the silica or clay has a porosity, the transmissivity of the superabsorbent polymer may be further improved by adding these crosslinked reactions.

 There is no limitation in the structure about the method of adding the said surface crosslinking agent to a polymer. The surface crosslinking agent and the polymer powder may be mixed in a reaction tank, or a method of spraying the surface crosslinking agent on the polymer powder, a method of continuously supplying the polymer and the surface crosslinking agent to a mixer operated continuously, and the like may be used.

When the surface crosslinking agent is added, water, a low alcohol (e.g., methanol) or a mixture thereof may be mixed together as a solvent. When the solvent is added, there is an advantage that the surface crosslinker can be evenly dispersed in the polymer. At this time, the content of the solvent is about 0.1 to about 1 part by weight based on 100 parts by weight of the polymer for the purpose of inducing even dispersion of the surface crosslinking agent and preventing aggregation of the polymer powder and optimizing the surface penetration depth of the crosslinking agent. Is preferably added. By heating for about 15 to about 120 minutes at a temperature of about 140 to about 220 ° C, preferably about 160 to about 200 ° C : preferably about 30 to about 110 minutes The surface crosslinking reaction and drying may take place simultaneously. If the crosslinking reaction temperature is less than 140 ° C, surface crosslinking reaction may not occur, and if it exceeds 220 ° C, foreign substances and odors may be generated due to carbonization, or property degradation and stable process operating conditions may be secured due to excessive reaction. Missing problems can occur. In addition, when the crosslinking reaction time is too short (less than 20 minutes), sufficient crosslinking reaction cannot be performed, and when the crosslinking reaction time exceeds 120 minutes, due to excessive surface crosslinking reaction, property degradation due to damage of the polymer particles may occur. have. The temperature raising means for surface crosslinking reaction is not specifically limited. It can be heated by supplying a heat medium or by directly supplying a heat source. In this case, as the type of heat medium that can be used, a heated fluid such as steam, hot air, or hot oil may be used, but the present invention is not limited thereto, and the temperature of the heat medium to be supplied is a means of heating medium, a temperature increase rate, and a temperature increase. considering the target temperature can be 'appropriately selected. On the other hand, the heat source directly supplied may be a heating method through electricity, a gas heating method, but the present invention is not limited to the above examples.

 The superabsorbent polymer obtained according to the production method of the present invention as described above has improved water retention, pressure absorption capacity and transmittance.

 As described above, the super absorbent polymer prepared according to the production method of the present invention has a water retention capacity (CRC) of about 25 to 50 g / g, preferably about 30 to about 40 g / g, measured according to the EDANA method WSP 241.2. The pressure absorption capacity (AUP) measured according to the EDANA method WSP 242.2 is about 10 to about 30 g / g, preferably about 15 to about 30 g / g, showing excellent water retention and pressure absorption capacity. In particular, in the case of the pressure absorbing ability, it may exhibit an effect of improving the pressure absorbing ability of about 5% or more, for example, about 5 to about 20%, or about 10 to about 20%, than when the hydrophobic alcohol is not used as the surface crosslinking agent.

Hereinafter, the operation and effects of the invention will be described in more detail with reference to specific examples of the invention. However, this embodiment is presented as an example of the invention The scope of the invention is not limited thereto.

<Example>

 Preparation Example: Preparation of Base Resin

 100 g of acrylic acid, 121.5 g of 32% sodium hydroxide (NaOH), 0.2 g of sodium persulfate as thermal polymerization initiator, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide 0.008 g as photopolymerization initiator , Polyethyleneglycol disylate (PEGDA, trade name: Mirama 280, obtained from: Miwon Chemical, weight average molecular weight: 400 g / mol) and 0.23 g of water were mixed to prepare a monomer composition having an acrylic acid concentration of 46% by weight. .

The monomer composition was fed at a feed rate of 500 to 2,000 mL / min on a rotating belt having a width of 10 cm and a length of 2 m and rotating at a speed of 50 cm / min. The polymerization reaction was performed for 60 seconds by irradiating ultraviolet rays having an intensity of 10 mW / cm 2 simultaneously with the supply of the monomer composition. After the polymerization reaction was completed, the mixture was cut by a meat chopper method and dried at 180 ° C. for 1 hour using a convection oven.

 After drying, it was pulverized with a pulverizer and classified to select a 150 to 850μπι size to prepare a base resin having a water retention capacity of 50 g / g. Example 1

Base resin of preparation example (50 g / g water retention capacity (CRC), 7.8 g / g pressurized absorption capacity (AUL)) 3.2 g of water, 4.0 g of methanol, 0.088 g of 2,2-dimethyl-1,3-propanediol and silica 0.008 g (trade name DM30S) were mixed to perform a surface crosslinking reaction for 60 minutes at a temperature of 185 ° C.

 After the surface crosslinking reaction, it was classified into a standard mesh of ASTM standard and was 150 to

A super absorbent polymer having a particle size of 850 / mm 3 was obtained. Example 2

Super absorbent polymer was prepared in the same manner as in Example 1, except that the surface crosslinking reaction was performed for 80 minutes. Example 3

 Superabsorbent polymer was prepared in the same manner as in Example 1, except that the surface crosslinking reaction was performed for 110 minutes. Comparative Example 1

2 g of water, 4.0 g of methanol, 0.088 g of 1,3-propanediol and 0.008 g of silica (trade name DM30S) were mixed with 100 g of the base resin of Preparation Example, and a surface crosslinking reaction was performed at a temperature of 185 ° C for 50 minutes.

 After the surface crosslinking reaction, the mixture was classified into a standard mesh of ASTM specification and 150 / m to

A super absorbent polymer having a particle size of 850 was obtained. Comparative Example 2

 A super absorbent polymer was prepared in the same manner as in Comparative Example 1 except that the surface crosslinking reaction was performed for 60 minutes. Comparative Example 3

 A super absorbent polymer was prepared in the same manner as in Comparative Example 1 except that the surface crosslinking reaction was performed for 90 minutes.

Experimental Example

 For the superabsorbent polymers of Examples and Comparative Examples, the following method was measured for physical properties, and the results are shown in Table 1. 1) Centrifugal Retention Capacity (CRC)

The superabsorbent polymers of the Examples and Comparative Examples were measured for centrifugal water retention (CRC) by unloaded absorption ratio according to EDANA method WSP 241.2. Specifically, examples and classifying the resin obtained resin obtained in Comparative example to 300 to 600 microns (), and the size W (g) (about 0. 2 g) placed uniformly on the envelope of the non-woven fabric sealed (seal) by After that, in normal saline of 0.9 mass% at room temperature Impregnated. After 30 minutes, the envelope was centrifuged and drained at 250 G for 3 minutes, and then the mass W2 (g) of the envelope was measured. Moreover, after carrying out the same operation without using resin, the mass W1 (g) at that time was measured. Using each mass obtained, CRC (g / g) was computed according to the following formula.

 [Calculation 1]

 CRC (g / g) = {(W2 (g)-Wl (g) -W (g)}) / W (g)}

 In the above formula,

 W (g) is the weight (g) of the absorbent resin,

Wl (g) is a nonwoven absorbent bag containing 0.9% by weight of saline solution at room temperature . Device weight measured after 30 minutes of impregnation and dehydration at 250G for 3 minutes using a centrifuge,

 W2 (g) is the device weight including water absorbent resin after 30 minutes impregnation of 0.9% by weight of physiological saline in a nonwoven bag containing water absorbent resin and then dehydrated at 250G for 3 minutes using a centrifuge. .

2) Absorbency under Load (AUL)

 The absorbency under pressure (AUL) of the superabsorbent polymers of the Examples and Comparative Examples was measured according to the EDANA method WSP 242.2.

Specifically, the obtained resin is classified into 300-600 micrometers Cam) size, and W (g) (about 0.16g, A) is evenly sprayed on the AUL cylinder, and the 0.9psi weight is raised and weighed (B). 0.9 mass 0/0 up to a Petri dish containing a physiological saline was swollen for 60 minutes. After 60 minutes, taken out and weighed (C),

 Using each mass obtained, AUL (g / g) was computed according to the following formula.

 [Calculation 2]

 AUL (g / g) = (C-B) / A

 Where

 A is the weight of absorbent resin (g) ,

 B is the weight of the AUL Kit assembly with absorbent resin,

C is after swelling for 60 minutes in 0.9% by weight of physiological saline solution The weight of the AUL Kit assembly.

 Table 1

Figure imgf000018_0001
As can be seen in Table 1, in the case of using the hydrophobic alcohol as a surface crosslinking agent, the pressure absorption capacity was improved compared to the comparative example using a hydrophilic alcohol under the same reaction conditions.

 In addition, in Comparative Examples 1 to 3, both the water-retaining capacity and the pressure-absorbing capacity decreased as the surface crosslinking reaction time increased. In Examples 1 to 3, the water-retaining capacity was slightly decreased but the pressure-absorbing capacity was maintained without decreasing. Seemed.

Claims

[Patent Claims]
 [Claim 1]
 Forming a hydrogel polymer by thermally polymerizing or photopolymerizing a monomer composition including a water-soluble ethylene-based unsaturated monomer and a polymerization initiator; Drying the hydrogel polymer;
 Pulverizing the dried polymer; And
 And mixing the ground polymer with a surface crosslinking agent comprising a hydrophobic alcohol to perform surface crosslinking reaction. [Claim 2]
 The method for producing a super absorbent polymer according to claim 1, wherein the hydrophobic alcohol is selected from the group consisting of 4 to 10 carbon atoms, and a polyhydric alcohol containing a branched alkyl group. [Claim 3]
 The method of claim 2, wherein the hydrophobic alcohol is 2,2-dimethyl-1,3-propanedi (2,
2- Dimethyl-l,
3-propanediol), a method for producing a super absorbent polymer.
[Claim 4]
 The method of claim 1, wherein the hydrophobic alcohol is contained in an amount of 0.01 to 10 parts by weight based on 100 parts by weight of the polymer.
[Claim 5]
 The method for preparing a super absorbent polymer according to claim 1, further comprising a surface crosslinked semi-finished porous silica or clay.
[Claim 6]
The method for producing a super absorbent polymer according to claim 1, wherein the water absorbency (CRC) of the super absorbent polymer is 25 to 50 g / g, and the pressurized absorbent capacity (AUP) is 10 to 30 g / g. [Claim 7]
The method of claim 11, wherein the surface crosslinking reaction is performed at a temperature of 140 to 220 ° C. for 120 minutes.
PCT/KR2016/002725 2015-12-23 2016-03-17 Method for production of super-absorbent resin WO2017111205A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR950006118B1 (en) * 1991-01-22 1995-06-09 다나까 쇼소 Method for production of absorbent resin
KR20110049072A (en) * 2009-11-04 2011-05-12 주식회사 엘지화학 Preparation method for water absorbent resin with high productivity
KR20110136597A (en) * 2010-06-15 2011-12-21 주식회사 엘지화학 Preparation method of super absorbent polymer
KR20120054836A (en) * 2010-11-22 2012-05-31 주식회사 엘지화학 Preparation method of super absorbent polymer
KR20130120300A (en) * 2012-04-25 2013-11-04 주식회사 엘지화학 Preparation method of super absorbent polymer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR950006118B1 (en) * 1991-01-22 1995-06-09 다나까 쇼소 Method for production of absorbent resin
KR20110049072A (en) * 2009-11-04 2011-05-12 주식회사 엘지화학 Preparation method for water absorbent resin with high productivity
KR20110136597A (en) * 2010-06-15 2011-12-21 주식회사 엘지화학 Preparation method of super absorbent polymer
KR20120054836A (en) * 2010-11-22 2012-05-31 주식회사 엘지화학 Preparation method of super absorbent polymer
KR20130120300A (en) * 2012-04-25 2013-11-04 주식회사 엘지화학 Preparation method of super absorbent polymer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP3321307A4 *

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