WO2020122426A1 - Super absorbent polymer and preparation method therefor - Google Patents

Super absorbent polymer and preparation method therefor Download PDF

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Publication number
WO2020122426A1
WO2020122426A1 PCT/KR2019/015056 KR2019015056W WO2020122426A1 WO 2020122426 A1 WO2020122426 A1 WO 2020122426A1 KR 2019015056 W KR2019015056 W KR 2019015056W WO 2020122426 A1 WO2020122426 A1 WO 2020122426A1
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Prior art keywords
polymer
super absorbent
absorbent polymer
fibers
weight
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PCT/KR2019/015056
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French (fr)
Korean (ko)
Inventor
최용석
홍연우
신은지
안태빈
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주식회사 엘지화학
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Priority claimed from KR1020190139625A external-priority patent/KR102603201B1/en
Application filed by 주식회사 엘지화학 filed Critical 주식회사 엘지화학
Priority to US16/968,771 priority Critical patent/US11559784B2/en
Priority to CN201980010268.4A priority patent/CN111655764A/en
Priority to EP19896615.2A priority patent/EP3722353A4/en
Priority to JP2020539707A priority patent/JP7034535B2/en
Publication of WO2020122426A1 publication Critical patent/WO2020122426A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/44—Polymerisation in the presence of compounding ingredients, e.g. plasticisers, dyestuffs, fillers
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F2/00—Processes of polymerisation
    • C08F2/46—Polymerisation initiated by wave energy or particle radiation
    • C08F2/48—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light
    • C08F2/50—Polymerisation initiated by wave energy or particle radiation by ultraviolet or visible light with sensitising agents
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F20/00—Homopolymers 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
    • C08F20/02—Monocarboxylic acids having less than ten carbon atoms, Derivatives thereof
    • C08F20/04—Acids, Metal salts or ammonium salts thereof
    • C08F20/06—Acrylic acid; Methacrylic acid; Metal salts or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/12—Powdering or granulating
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J3/00—Processes of treating or compounding macromolecular substances
    • C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
    • C08J9/10—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing nitrogen, the blowing agent being a compound containing a nitrogen-to-nitrogen bond
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
    • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
    • C08J9/12—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent
    • C08J9/14—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a physical blowing agent organic
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L33/00—Compositions of homopolymers or 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 of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers
    • C08L33/02—Homopolymers or copolymers of acids; Metal or ammonium salts thereof
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L97/00—Compositions of lignin-containing materials
    • C08L97/02—Lignocellulosic material, e.g. wood, straw or bagasse

Definitions

  • the present invention relates to a super absorbent polymer and a method for manufacturing the same. More particularly, the present invention relates to a method for producing a super absorbent polymer having excellent basic absorption ability and improved absorption rate.
  • Super Absorbent Polymer is a synthetic polymer material that has the ability to absorb about 500 to 1,000 times its own weight, and has started to be put into practical use as a physiological tool. In addition to sanitary products such as gardening, it has been widely used as a material for soil repair agents for gardening, civil engineering, construction water supply materials, sheets for raising seedlings, freshness preservatives in the food distribution field, and poultices.
  • these superabsorbent polymers are widely used in the field of sanitary materials such as diapers and sanitary napkins. For this purpose, it is necessary to exhibit high absorbency for moisture, etc., and absorbed moisture does not come out even under external pressure. It is necessary to exhibit excellent absorption properties. In addition, in recent years, an absorption rate for absorbing and storing a target solution such as moisture more rapidly is further required. Basically, the absorption of the superabsorbent polymer into the aqueous solution occurs at the resin surface, so a method of increasing the surface area of the superabsorbent polymer can be considered to improve the absorption rate. Accordingly, a method for reducing the particle size of the super absorbent polymer or forming a porous structure has been considered as a method for increasing the absorption rate.
  • a method of manufacturing a superabsorbent polymer by adding a blowing agent to form a porous structure in a superabsorbent polymer has been proposed.
  • the higher the content of the blowing agent the absorption rate is improved to a certain level, but due to excessive foaming, the amount of fine powder generated in the super absorbent polymer increases, and there is a problem that the gel strength is lowered.
  • the superabsorbent polymer tends to have reduced basic absorption characteristics as the particle size decreases.
  • the known method has a limitation in improving the absorption rate while maintaining the basic absorption capacity.
  • the present invention is to solve the problems of the prior art as described above, and to provide a method of manufacturing a super absorbent polymer exhibiting improved initial absorption rate while having excellent basic absorption performance such as water retention capacity (CRC).
  • CRC water retention capacity
  • the fiber may be included in 1 to 18 parts by weight based on 100 parts by weight of the hydrogel polymer.
  • the length of the fiber may be 1 to 20 mm.
  • the width of the fiber may be 1 to 100 ⁇ m.
  • water may be further added in at least one of steps c) to e). At this time, the water may be added in 1 to 20 parts by weight based on 100 parts by weight of the hydrogel polymer.
  • the monomer composition may further include a blowing agent.
  • the monomer composition is alkyl sulfate salt (alkyl sulfate salt), alkyl sulfonate salt (alkyl sulfonate salt), alkyl phosphate salt (alkyl phosphate salt), alkyl carbonate salt (alkyl carbonate salt), polyethylene glycol alkyl ester (polyethylene glycol alkyl esters, polypropylene glycol alkyl esters, glucoside alkyl esters, glycerol alkyl esters, and block-copolymers of polyethylene glycol and polypropylene glycol (block- copolymers of polyethylene glycol and polypropylene glycol) may further include one or more foam stabilizers.
  • step g After step g),
  • i) may further include the step of proceeding the surface crosslinking reaction.
  • the surface crosslinking agent is a polyhydric alcohol compound; Epoxy compounds; Polyamine compounds; Halo epoxy compounds; Condensation products of haloepoxy compounds; Oxazoline compounds; Mono-, di- or polyoxazolidinone compounds; Cyclic urea compounds; Polyvalent metal salts; And it may be one or more selected from the group consisting of alkylene carbonate compounds.
  • the surface crosslinking agent may be added in an amount of 0.001 to 5 parts by weight based on 100 parts by weight of the mixture.
  • the present invention provides a super absorbent polymer produced by the above manufacturing method.
  • the present invention is a crosslinked polymer in which a water-soluble ethylenically unsaturated monomer is crosslinked and polymerized in the presence of an internal crosslinking agent, and base resin particles comprising at least one fiber among fluff pulp and synthetic polymer fibers;
  • the crosslinked polymer is a super absorbent polymer comprising a surface crosslinking layer further crosslinked via a surface crosslinking agent,
  • the superabsorbent polymer may have a centrifugal water retention capacity (CRC) of 25 to 45 g/g measured according to EDANA method WSP 241.3.
  • CRC centrifugal water retention capacity
  • the superabsorbent polymer may have a pressure absorption capacity (AUL) of 0.3 psi measured according to EDANA method WSP 242.3 of 25 to 40 g/g.
  • AUL pressure absorption capacity
  • the superabsorbent polymer composition is provided.
  • the method for producing a super absorbent polymer according to the present invention it is possible to provide a high quality super absorbent polymer having excellent basic absorbent performance such as centrifugal water retention capacity and exhibiting improved absorbent speed.
  • the manufacturing method of the super absorbent polymer of the present invention is relatively simple because the process steps are high, it is possible to obtain a super absorbent polymer having a high absorption rate.
  • Example 1 is a scanning electron microscope (SEM) photograph of the super absorbent polymer prepared in Example 1.
  • one or more fibers of fluff pulp and synthetic polymer fibers are added in the step of compacting the hydrogel polymer in order to realize an excellent absorption rate while maintaining the basic absorption performance of the super absorbent polymer.
  • the superabsorbent polymer prepared as described above exhibits an improved absorption rate compared to the existing superabsorbent polymer because fibers having excellent absorbent capacity are adsorbed on the surface.
  • the superabsorbent polymer prepared according to the present invention can exhibit a more improved absorption rate while maintaining basic absorbent properties such as water retention capacity.
  • a) a water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator are mixed to prepare a monomer composition.
  • any monomer commonly used in the production of superabsorbent polymers can be used without particular limitation. Any one or more monomers selected from the group consisting of anionic monomers and salts thereof, nonionic hydrophilic-containing monomers and amino group-containing unsaturated monomers and quaternaries thereof can be used.
  • (meth)acrylic acid maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethanesulfonic 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, methoxypolyethylene glycol (meth)acrylate or polyethylene glycol ( Nonionic hydrophilic monomers of meth)acrylate; And an amino group-containing unsaturated monomer of (N,N)-dimethylaminoethyl (meth) acrylate or (N,N)-dimethylaminopropyl (meth)acrylamide, and quaternaries thereof.
  • an acrylic acid or a salt thereof for example, an alkali metal salt such as acrylic acid or a sodium salt thereof may be used, and the use of such a monomer makes it possible to manufacture a super absorbent polymer having better physical properties.
  • an alkali metal salt of acrylic acid is used as a monomer, it can be used by neutralizing acrylic acid with a basic compound such as caustic soda (NaOH).
  • the concentration of the water-soluble ethylenically unsaturated monomer may be about 20 to about 60% by weight, preferably about 40 to about 50% by weight, with respect to the monomer composition containing the raw material and solvent of the superabsorbent polymer, and polymerization It may be an appropriate concentration in consideration of time and reaction conditions. However, if the concentration of the monomer is too low, the yield of the superabsorbent polymer may be low and economic problems may occur. Conversely, if the concentration is too high, a part of the monomer precipitates or the grinding efficiency of the polymerized hydrogel polymer is low. Such problems may occur in the process and physical properties of the super absorbent polymer may be deteriorated.
  • the polymerization initiator used in polymerization in the superabsorbent polymer production method of the present invention is not particularly limited as long as it is generally used for the production of superabsorbent polymers.
  • the polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator according to UV irradiation depending on the polymerization method.
  • a thermal polymerization initiator may be additionally included.
  • the photopolymerization initiator is a compound capable of forming radicals by light such as ultraviolet rays
  • the composition may be used without limitation.
  • the photopolymerization initiator includes, for example, benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketal. ketal), acyl phosphine, and alpha-aminoketone ( ⁇ -aminoketone).
  • acylphosphine a 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.
  • 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide
  • the photopolymerization initiator may be included in a concentration of about 0.01 to about 1.0% by weight relative to the monomer composition. If the concentration of the photopolymerization initiator is too low, the polymerization rate may be slow, and if the concentration of the photopolymerization initiator is too high, the molecular weight of the super absorbent polymer may be small and the properties may be uneven.
  • thermal polymerization initiator one or more selected from the initiator group consisting of a persulfate-based initiator, an azo-based initiator, hydrogen peroxide, and ascorbic acid may be used.
  • the persulfate-based initiator are sodium persulfate (Na 2 S 2 O 8 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate (Ammonium persulfate; (NH 4 ) 2 S 2 O 8 )
  • examples of the azo-based initiator are 2, 2-azobis-(2-amidinopropane) dihydrochloride (2, 2-azobis (2-amidinopropane) dihydrochloride), 2 , 2-azobis-(N, N-dimethylene)isobutyramidine dihydrochloride (2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride), 2-(carbamoyl azo)isobutyronit
  • the thermal polymerization initiator may be included in a concentration of about 0.001 to about 0.5% by weight relative to the monomer composition. If the concentration of the thermal polymerization initiator is too low, the additional thermal polymerization hardly occurs, so the effect of the addition of the thermal polymerization initiator may be negligible. If the concentration of the thermal polymerization initiator is too high, the molecular weight of the super absorbent polymer is small and the physical properties may be uneven. have.
  • the internal crosslinking agent while having at least one functional group capable of reacting with the water-soluble substituent of the water-soluble ethylenically unsaturated monomer, a crosslinking agent having at least one ethylenically unsaturated group; Alternatively, a crosslinking agent having two or more functional groups capable of reacting with the water-soluble substituent of the monomer and/or the water-soluble substituent formed by hydrolysis of the monomer may be used.
  • the internal crosslinking agent include bisacrylamide having 8 to 12 carbons, bismethacrylamide, poly(meth)acrylate of polyols having 2 to 10 carbons, or poly(meth)allyl ether of polyols having 2 to 10 carbons, etc. And more specifically, N,N'-methylenebis(meth)acrylate, ethyleneoxy(meth)acrylate, polyethyleneoxy(meth)acrylate, propyleneoxy(meth)acrylate, glycerin diacrylate , Glycerin triacrylate, trimethyrol triacrylate, triallylamine, triaryl cyanurate, triallyl isocyanate, polyethylene glycol, diethylene glycol and propylene glycol.
  • an epoxy compound containing one or more epoxy groups may be used as the internal crosslinking agent.
  • the epoxy compound may further include at least one functional group capable of reacting with the water-soluble ethylenically unsaturated monomer in addition to the epoxy group.
  • Specific examples include polyhydric epoxy compounds such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, propylene glycol diglycidyl ether, or polypropylene glycol diglycidyl ether. Can be lifted.
  • These internal crosslinking agents may be used in combination of two or more, and included in a concentration of about 0.01 to about 0.5% by weight relative to the monomer composition to crosslink the polymerized polymer.
  • the monomer composition may further include additives such as a foaming agent, a foaming stabilizer, a thickener, a plasticizer, a preservative stabilizer, and an antioxidant, if necessary.
  • additives such as a foaming agent, a foaming stabilizer, a thickener, a plasticizer, a preservative stabilizer, and an antioxidant, if necessary.
  • the blowing agent may be used without limitation, inorganic blowing agents and encapsulating blowing agents commonly used in the art.
  • the inorganic blowing agent is calcium carbonate (CaCO 3 ), sodium bicarbonate (NaHCO 3 ), ammonium bicarbonate (NH 4 HCO 3 ), ammonium carbonate ((NH 4 ) 2 CO 3 ), ammonium nitrite (NH 4 NO 2 ), hydrogen borohydride
  • CaCO 3 calcium carbonate
  • NaHCO 3 sodium bicarbonate
  • NH 4 HCO 3 ammonium bicarbonate
  • NH 4 HCO 3 ammonium carbonate
  • (NH 4 ) 2 CO 3 ) ammonium nitrite
  • hydrogen borohydride One or more selected from sodium (NaBH 4 ) and sodium carbonate (Na 2 CO 3 ) may be used, but is not limited thereto.
  • the encapsulated foaming agent exists in an encapsulated state during polymerization of the monomer composition, and then foams by heat applied during the drying process described below, thereby forming pores of appropriate size between the polymer structures of the super absorbent polymer, It is possible for the absorbent resin sheet to exhibit the structure of an open pore channel. Therefore, when the foaming agent encapsulated in the monomer composition is included, the absorption rate of the superabsorbent polymer can be further improved, which is preferable.
  • the encapsulated foaming agent may have a structure including a core including a hydrocarbon and a shell surrounding the core and formed of a thermoplastic resin.
  • the encapsulated foaming agent has different expansion characteristics depending on the weight and diameter of the components constituting the core and the shell, and can be expanded to a desired size by controlling it, and can control the porosity of the superabsorbent polymer sheet.
  • the expansion characteristics of the encapsulated blowing agent in order to determine whether pores of a desired size are formed, it is necessary to first grasp the expansion characteristics of the encapsulated blowing agent.
  • the form in which the foaming agent encapsulated in the superabsorbent polymer is foamed may vary depending on the manufacturing conditions of the superabsorbent polymer, so it is difficult to define it as one form. Therefore, by first foaming the encapsulated foaming agent in the air, the expansion ratio and size can be checked to confirm whether it is suitable for forming desired pores.
  • the encapsulated foaming agent may have an average diameter of 5 to 50 ⁇ m, or 5 to 30 ⁇ m, or 5 to 20 ⁇ m, or 7 to 17 ⁇ m. When the encapsulated foaming agent exhibits such an average diameter, it can be judged to be suitable for achieving an appropriate porosity.
  • the method of manufacturing the superabsorbent polymer sheet according to the present invention It can be judged to be suitable for forming a suitable open pore structure.
  • the hydrocarbons constituting the core of the encapsulated blowing agent are n-propane, n-butane, iso-butane, cyclobutane, n-pentane, iso-pentane, cyclopentane, n-hexane, iso-hexane, cyclohexane, n- It may be one or more selected from the group consisting of heptane, iso-heptane, cycloheptane, n-octane, iso-octane and cyclooctane.
  • hydrocarbons having 3 to 5 carbon atoms are suitable for forming pores of the size described above, and iso- Butane may be the most suitable.
  • thermoplastic resin constituting the shell of the encapsulated foaming agent is formed from at least one monomer selected from the group consisting of (meth)acrylate, (meth)acrylonitrile, aromatic vinyl, vinyl acetate, vinyl halide, and vinylidene halide. It can be a polymer. Among them, a copolymer of (meth)acrylate and (meth)acrylonitrile may be most suitable for forming pores of the size described above.
  • the encapsulated blowing agent may contain 10 to 30% by weight of hydrocarbons based on the total encapsulated blowing agent weight. It may be most suitable to form an open pore structure within this range.
  • the encapsulated foaming agent may be prepared and used, or a commercialized foaming agent satisfying the above-described conditions may be used.
  • the content of the encapsulating foaming agent may be 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 1 part by weight based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. If the content of the encapsulated foaming agent is too small, the open pore structure may not be properly formed, and if it is contained too much, the porosity may be too high, so that the strength of the super absorbent polymer may be weak, so the content range is preferable in this respect. Can be.
  • the monomer composition may further include a foaming stabilizer.
  • the foam stabilizer is an alkyl sulfate salt, an alkyl sulfonate salt, an alkyl phosphate salt, an alkyl carbonate salt, and a polyethylene glycol alkyl ester. ), polypropylene glycol alkyl ester, glucoside alkyl ester, glycerol alkyl ester, block-copolymers of polyethylene glycol and polypropylene glycol glycol and polypropylene glycol) or mixtures thereof.
  • the alkyl group is not particularly limited, and may be a straight chain, branched chain or cyclic alkyl group having 1 to 30 carbon atoms.
  • the foaming stabilizer may be included in a concentration of about 0.0001 to 0.1% by weight or about 0.001 to 0.1% by weight in 100% by weight of the monomer composition to improve the foaming efficiency of the foaming agent to form a crosslinked polymer having an appropriate pore structure.
  • Raw materials such as the water-soluble ethylenically unsaturated monomer, photopolymerization initiator, thermal polymerization initiator, internal crosslinking agent, and additives described above may be prepared in the form of a solution of a monomer composition dissolved in a solvent.
  • the solvent that can be used at this time can be used without limitation of its composition as long as it can dissolve the above-mentioned components, for example, water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, Propylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl amyl ketone, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol Ethyl ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate and N,N-dimethylacetamide can be used in combination.
  • the solvent may be included in the remaining amount excluding the above-mentioned components with respect to the total content of the monomer composition.
  • the monomer composition is thermally polymerized or photopolymerized to prepare a hydrogel polymer.
  • the thermal polymerization or photopolymerization method of the monomer composition is not particularly limited as long as it is a commonly used polymerization method.
  • the polymerization method is largely divided into thermal polymerization and photopolymerization according to the polymerization energy source, and in general, when performing thermal polymerization, it can be carried out in a reactor having a stirring axis such as a kneader, and when performing photopolymerization, it is movable Although it may be carried out in a reactor equipped with a conveyor belt, the polymerization method described above is an example, and the present invention is not limited to the polymerization method described above.
  • a hydrogel polymer obtained by thermal polymerization by supplying hot air or heating a reactor to a reactor such as a kneader having a stirring shaft is used as a reactor outlet, depending on the type of the stirring shaft provided in the reactor.
  • the discharged hydrogel polymer may be in the form of several centimeters to several millimeters.
  • the size of the hydrogel polymer obtained may vary depending on the concentration and injection speed of the monomer composition to be injected, and a hydrogel polymer having a weight average particle diameter of 2 to 50 mm can be usually obtained.
  • the shape of the hydrogel polymer usually obtained may be a hydrogel polymer on a sheet having a belt width.
  • the thickness of the polymer sheet varies depending on the concentration and the injection rate 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.
  • the monomer composition is supplied to such an extent that the thickness of the polymer on the sheet is too thin, production efficiency is low, which is undesirable.
  • the thickness of the polymer on the sheet exceeds 5 cm, due to the excessively thick thickness, the polymerization reaction does not occur evenly over the entire thickness. It may not.
  • the normal water content of the hydrogel polymer obtained in this way may be about 40 to about 80% by weight.
  • water content refers to a value obtained by subtracting the weight of the polymer in a dry state from the weight of the hydrogel polymer as the content of moisture to the total weight of the hydrogel polymer. Specifically, it is defined as a calculated value by measuring the weight loss due to evaporation of water in the polymer during the drying process by raising the temperature of the polymer through infrared heating.
  • the drying condition is a method of raising the temperature from room temperature to about 180°C and then maintaining it at 180°C.
  • the total drying time is set to 20 minutes including 5 minutes of the temperature rise step to measure the water content.
  • the used grinder is not limited in configuration, but specifically, a vertical cutter (Vertical pulverizer), a turbo cutter (Turbo cutter), a turbo grinder (Turbo grinder), a rotary cutting mill (Rotary cutter mill), cutting Cutter mill, disc mill, shred crusher, crusher, chopper, and disc cutter
  • a vertical cutter Very pulverizer
  • turbo cutter Turbo cutter
  • Turbo grinder turbo grinder
  • rotary cutting mill Rotary cutting mill
  • cutting Cutter mill disc mill
  • shred crusher crusher
  • chopper chopper
  • disc cutter rotary cutting mill
  • step c) may be performed so that the particle diameter of the hydrogel polymer is about 2 to about 20 mm.
  • Coarse pulverization with a particle diameter of less than 2 mm is not technically easy due to the high water content of the hydrogel polymer, and there may also be a phenomenon in which the particles are aggregated with each other.
  • the particle size is roughly crushed to more than 20 mm, the effect of increasing the efficiency of the drying step to be performed later may be insignificant.
  • the fibers adsorbed on the surface of the hydrogel polymer particles may be incorporated into the particles by the chopper. Accordingly, at least a portion of the fibers are mixed in a form penetrating the inside of the particles of the base resin, and fibers may be distributed both inside and outside the base resin particles. As described above, the fibers distributed inside and outside of the base resin serve to absorb the surrounding moisture rapidly through the capillary action and transfer it to the polymer. Therefore, the superabsorbent polymer prepared according to the present invention can exhibit an improved initial absorption rate.
  • such fibers are easy to apply to the process and are not only inexpensive, but also harmless to the human body, and according to the present invention, it is possible to manufacture a superabsorbent polymer that is human-friendly and excellent in absorbency in a simple and economical manner.
  • the fluff pulp is a cellulose fluff pulp, but may be wood fluff pulp such as softwood kraft paper, broadleaf kraft pulp, but is not limited thereto, and fluff pulp used for absorbent articles may be used without limitation.
  • the synthetic polymer fiber may be at least one selected from the group consisting of nylon, polypropylene, polyethylene, polyester, polyacrylonitrile, polyvinyl chloride, polyvinyl alcohol, polyacrylate, and acetate.
  • Such a synthetic polymer fiber is excellent in hygroscopicity, and it is easy to control the width or length of the fiber, so it is possible to easily control the physical properties of the super absorbent polymer.
  • the fiber may be preferably used having a length of 1 to 20 mm.
  • the fiber may preferably have a width of 1 to 100 ⁇ m. If the length of the fiber exceeds the above range or the width is too wide, a load may occur in the process of compacting the water-containing gel polymer and the fiber, and it is difficult to adsorb the fiber inside and outside the base resin particles, so that the super absorbent polymer is It can be difficult to evenly distribute the fibers.
  • the length of the fiber is too short or the width is too narrow, the effect of improving the properties of the super absorbent polymer may be insignificant, so it is preferable to satisfy the above range.
  • the surface crosslinking solution can be more evenly applied regardless of the particle size variation of the base resin particles in the subsequent surface crosslinking step, the surface crosslinking efficiency can be further increased.
  • the adsorption rate deviation with the small particles may be reduced due to the adsorbed fibers. Therefore, regardless of the particle size of the base resin, the degree of application of the surface crosslinking solution becomes uniform, and the variation in crosslinking degree decreases, thereby improving the overall physical property balance of the superabsorbent polymer produced.
  • the length of the fibers may be 2 mm or more, or 3 mm or more, and 15 mm or less, or 10 mm or less.
  • the fiber having an average length of 3 to 10 mm may be preferably used.
  • the average length of the fibers can be derived by randomly selecting 100 fibers, measuring the length of individual fibers, and calculating the average value thereof.
  • the width of the fiber may be 10 ⁇ m or more, 15 ⁇ m or more, 30 ⁇ m or more, or 50 ⁇ m or more, and 90 ⁇ m or less, or 80 ⁇ m or less.
  • the content of the fiber may be 1 part by weight or more, 3 parts by weight or more, or 5 parts by weight or more, and 18 parts by weight or less, 15 parts by weight or less, or 10 parts by weight or less based on 100 parts by weight of the hydrogel polymer. If the fiber is less than 1 part by weight based on 100 parts by weight of the hydrogel polymer, the effect of improving the absorption rate due to the inclusion of the fiber cannot be secured, and if it exceeds 18 parts by weight, the centrifugal water retention capacity (CRC) of the superabsorbent polymer produced is Basic absorption performance such as pressurized absorption capacity (AUL) and absorption rate may be lowered, and a problem that mechanical load increases in the step of compacting the hydrogel polymer may occur.
  • AUL pressurized absorption capacity
  • steps d) and e) may be repeated 2 to 5 times.
  • steps d) and e) may be repeated 2 to 5 times.
  • the same amount of fibers can be added for each repetition for smooth mixing, but it is preferable that the total content of the added fibers is within the above range.
  • water may be further added in at least one of the steps c) to e). Adding an appropriate amount of water to the step of compacting the hydrogel polymer can lower the load of the grinder, the hydrogel polymer can be more evenly compacted, and accordingly the particle size of the hydrogel polymer can be easily adjusted.
  • the water may be distilled water, and the amount of water added in each step is not particularly limited, but may be, for example, 1 to 20 parts by weight based on 100 parts by weight of the hydrogel polymer.
  • the hydrogel polymer containing fibers it is preferable that the particle size is in the range of 1 to 15 mm. In the particle size range, the efficiency of the drying step may be increased.
  • the drying temperature of the drying step may be about 150 to about 200 °C.
  • the drying temperature is less than 150°C, the drying time is too long and there is a fear that the physical properties of the superabsorbent resin to be formed are lowered.
  • the drying temperature exceeds 200°C, only the polymer surface is dried excessively, and a subsequent grinding process is performed. In the fine powder may be generated, there is a fear that the physical properties of the superabsorbent polymer to be formed finally decreases. Therefore, preferably, the drying may be performed at a temperature of about 150 to about 200°C, more preferably at a temperature of about 160 to about 180°C.
  • process efficiency and the like may be considered, but may be performed for about 20 minutes to about 1 hour, but is not limited thereto.
  • the drying method of the drying step may also be selected and used without limitation, as long as it is commonly used as a drying process for the hydrogel polymer. Specifically, the drying step may be performed by a method such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation.
  • the moisture content of the polymer after the drying step may be about 0.1 to about 10% by weight.
  • the polymer powder obtained after the grinding step may have a particle size of about 150 to about 850 ⁇ m.
  • the pulverizer used for pulverizing to such a particle size is specifically, a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill or a jog. A mill may be used, but the present invention is not limited to the examples described above.
  • the polymer powder obtained after pulverization is generally classified according to particle size.
  • it may be subjected to a step of classifying particles having a particle diameter of less than about 150 ⁇ m, particles having a diameter of about 150 to about 850 ⁇ m, and particles having a particle diameter of greater than 850 ⁇ m.
  • the method for preparing a super absorbent polymer of the present invention may further include h) adding a surface crosslinking agent to the mixture obtained after step g), and i) progressing a surface crosslinking reaction.
  • the surface crosslinking step is a step of forming a superabsorbent polymer having improved physical properties by inducing a crosslinking reaction on the surface of the mixture, that is, a polymer containing fibers on the surface, in the presence of a surface crosslinking agent.
  • a surface crosslinking layer (surface modification layer) is formed on the surface of the pulverized polymer particles.
  • the surface crosslinking agent is applied to the surface of the superabsorbent polymer particles, so that the surface crosslinking reaction occurs on the surface of the superabsorbent polymer particles, which improves the crosslinkability on the surface of the particles without substantially affecting the inside of the particles. Therefore, the surface-crosslinked superabsorbent polymer particles have a higher degree of crosslinking near the surface than from the inside.
  • any surface crosslinking agent that has been used in the manufacture of super absorbent polymers can be used without any limitation. More specific examples thereof, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, 2-methyl- One or more polyols selected from the group consisting of 1,3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, tripropylene glycol and glycerol ; At least one carbonate-based compound selected from the group consisting of ethylene carbonate and propylene carbonate; Epoxy compounds such as ethylene glycol diglycidyl ether; Oxazoline compounds such as oxazolidinone; Polyamine compounds; Oxazoline
  • the surface crosslinking agent may be used in an amount of about 0.01 to 5 parts by weight based on 100 parts by weight of the mixture obtained in step g).
  • the content range of the surface crosslinking agent By adjusting the content range of the surface crosslinking agent to the above-described range, it is possible to provide a super absorbent polymer exhibiting excellent water absorption properties.
  • the surface crosslinking agent may be dry mixed with the mixture obtained in step g) or may be added in the form of a surface crosslinking solution.
  • Water, methanol, ethanol, propylene glycol, and combinations thereof may be used as the solvent of the surface crosslinking solution, but are not limited thereto.
  • a polyvalent metal salt, an inorganic filler, a thickener, and the like may be further included as necessary.
  • These additives may be dry mixed with the mixture obtained in step g), or in the form added to the surface crosslinking solution.
  • the polyvalent metal salt may further include, for example, at least one selected from the group consisting of aluminum salts, more specifically aluminum sulfates, potassium salts, ammonium salts, sodium salts, and hydrochloride salts.
  • the liquid permeability of the superabsorbent polymer produced by the method of one embodiment can be further improved.
  • the polyvalent metal salt may be added to the surface crosslinking solution together with the surface crosslinking agent, and may be used in an amount of 0.01 to 4 parts by weight based on 100 parts by weight of the base resin.
  • the inorganic filler may include silica, aluminum oxide, or silicate.
  • the inorganic filler may be included in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the base resin powder.
  • Such an inorganic filler can act as a lubricant to improve the application efficiency of the surface crosslinking solution on the surface of the super absorbent polymer, and further improve the liquid permeability of the prepared super absorbent polymer.
  • a thickener may be further included.
  • a thickener may be further included.
  • one or more selected from polysaccharides and hydroxy-containing polymers may be used as the thickener.
  • the polysaccharide a gum-based thickener and a cellulose-based thickener may be used.
  • the gum-based thickener examples include xanthan gum, arabic gum, karaya gum, tragacanth gum, ghatti gum, guar gum (guar gum), locust bean gum (locust bean gum) and silylium seed gum, and the like
  • specific examples of the cellulose-based thickener include hydroxypropyl methyl cellulose, carboxymethyl cellulose, and methyl cellulose , Hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxymethylpropylcellulose, hydroxyethylhydroxypropylcellulose, ethylhydroxyethylcellulose and methylhydroxypropylcellulose You can.
  • specific examples of the hydroxy-containing polymer include polyethylene glycol and polyvinyl alcohol.
  • the surface crosslinking reaction may be performed by heating the mixture of the pulverized hydrogel polymer, the surface crosslinking agent, and the fibers to raise the temperature.
  • the surface crosslinking step may be performed by heating at a temperature of 185°C or higher, preferably 185 to about 230°C, for about 10 to about 90 minutes, preferably about 20 to about 70 minutes. If the crosslinking reaction temperature is less than 185 °C or the reaction time is too short, there may be a problem that the surface crosslinking agent does not sufficiently react with the hydrogel polymer, and if it exceeds 230 °C or the reaction time is too long, the hydrogel polymer decomposes and physical properties Degradation problems may occur.
  • the heating means for the surface crosslinking reaction is not particularly limited.
  • the heating medium may be supplied or a heat source may be directly supplied to heat.
  • a heated fluid such as steam, hot air, and hot oil may be used, but the present invention is not limited to this, and the temperature of the heat medium supplied is the means of the heat medium, the rate of temperature increase, and the temperature increase. It can be appropriately selected in consideration of the target temperature.
  • the heat source directly supplied may include a heating method through electricity or a gas, but the present invention is not limited to the above-described example.
  • a surface modification layer may be formed on the surface of the polymer.
  • the superabsorbent polymer prepared according to the manufacturing method of the present invention exhibits an improved absorption rate as it includes at least one fiber among fluff pulp and synthetic polymer fibers.
  • the water-soluble ethylenically unsaturated monomer is a crosslinked polymer crosslinked in the presence of an internal crosslinking agent, and base resin particles comprising at least one fiber of fluff pulp and synthetic polymer fibers; And it is formed on the surface of the base resin particles, the cross-linking polymer is a super absorbent polymer comprising a surface cross-linking layer further cross-linked through a surface cross-linking agent, at least a portion of the fiber penetrates the interior of the base resin particles A superabsorbent polymer that is incorporated is provided.
  • the superabsorbent polymer of the present invention includes fibers having excellent hygroscopicity in the process of compacting a hydrogel polymer during base resin production, and fibers can be evenly distributed inside and outside the base resin on the particles. Accordingly, the superabsorbent polymer of the present invention has excellent basic absorption performance such as water retention capacity and pressure absorption capacity, and can exhibit improved absorption speed and liquid permeability.
  • the superabsorbent polymer has a water retention capacity (CRC) measured according to EDANA method WSP 241.3 of about 25 g/g or more, 28 g/g or more, or about 30 g/g or more, and about 45 g/g. Or less, 40 g/g or less, or about 35 g/g or less.
  • CRC water retention capacity
  • the superabsorbent polymer has a pressure absorption capacity (AUL) of 0.3 psi measured according to EDANA method WSP 242.3 of 25 g/g or more, or 27 g/g or more, and 40 g/g or less, or 30 g/g or less. Can be.
  • AUL pressure absorption capacity
  • the superabsorbent polymer is added to 2 g of superabsorbent polymer in 50 mL of physiological saline at 23°C to 24°C, and a magnetic bar (8 mm in diameter and 31.8 mm in length) is stirred at 600 rpm to obtain vortex.
  • the vortex time measured in seconds until disappearance, may be 50 seconds or less, or 45 seconds or less.
  • the lower the absorption rate, the better, and the lower limit is not limited, but may be, for example, 10 seconds or more, or 20 seconds or more.
  • superabsorbent polymer particles includes a fluff pulp and one or more fibers of synthetic polymer fibers, at least a portion of the fiber is provided with a superabsorbent polymer composition that penetrates through the interior of the superabsorbent polymer particles.
  • the superabsorbent polymer composition in the superabsorbent polymer composition, a part of the fibers are present outside the superabsorbent polymer particles, and some are present in a state embedded in the superabsorbent polymer particles. Accordingly, the superabsorbent polymer composition of the present invention can exhibit an improved absorption rate compared to a composition in which a superabsorbent polymer and hygroscopic fiber are simply mixed.
  • a photopolymerization reaction was performed on the monomer aqueous solution composition to obtain a polymerized sheet.
  • the polymerized sheet was taken out and cut to a size of 3 cm X 3 cm, and then chopping was performed using a meat chopper.
  • a meat chopper hole size 16 mm, speed 60 Hz
  • 5 parts by weight of distilled water with respect to 100 parts by weight of hydrogel polymer, and each fiber in Table 1 below It was added according to the content described in 1 (expressed as parts by weight compared to 100 parts by weight of the gel-like polymer), and again minced to a meat chopper (hole size 16 mm, speed 60 Hz).
  • 5 parts by weight of distilled water was sprayed onto the compacted hydrogel polymer, followed by compaction with a meat chopper (hole size 16 mm, speed 60 Hz) to prepare a crumb.
  • the crumb was dried in an oven capable of transferring air volume up and down.
  • the hot air at 185° C. was uniformly dried by flowing from bottom to top for 15 minutes and from top to bottom for 15 minutes, and after drying, the water content of the dried body was set to 2% or less. After drying, it was crushed with a grinder, and then divided into 10 minutes with Amplitude 1.5 mm (classification mesh combination: #20 / #30 / #50 / #100) and each classification (10% / 65% / 22% / 3 %) was collected to obtain a base resin powder having a particle diameter of about 150 ⁇ m to 850 ⁇ m.
  • a superabsorbent polymer was prepared in the same manner as in Example 1, except that fibers were not added in the process of compacting the hydrogel polymer.
  • Example 1 To 100 parts by weight of the superabsorbent polymer of Comparative Example 1, 5 parts by weight of fluff pulp used in Example 1 was added and mixed to prepare a superabsorbent polymer composite in which a superabsorbent polymer and fluff pulp were simply mixed.
  • the pressure absorption capacity of 0.3 psi of each resin was measured according to EDANA method WSP 242.3. In the measurement of the pressure absorption capacity, the resin classifier for the CRC measurement was used.
  • a 400 mesh wire mesh made of stainless steel was mounted on a cylindrical bottom of a plastic having an inner diameter of 25 mm.
  • a glass filter having a diameter of 90 mm and a thickness of 5 mm was placed inside the petri dish of 150 mm in diameter, and the physiological saline composed of 0.9 wt% sodium chloride was brought to the same level as the top surface of the glass filter.
  • a sheet of filter paper having a diameter of 90 mm was placed thereon. The measuring device was mounted on a filter paper, and the liquid was absorbed for 1 hour under a load. After 1 hour, the measuring device was lifted, and the weight W5 (g) was measured.
  • the absorption rate of each resin was measured in seconds according to the method described in International Patent Publication No. 1987-003208.
  • the absorption rate is 2 g of superabsorbent resin in 50 mL of physiological saline at 23°C to 24°C, and the magnetic bar (8 mm in diameter and 31.8 mm in length) is stirred at 600 rpm to vortex. It was calculated by measuring the time until (vortex) disappears in seconds.
  • the average length of the fiber is the average value of the length derived by randomly selecting 100 fibers.
  • the superabsorbent polymer prepared according to the present invention is superior in basic physical properties such as CRC and AUL, but the pulp fiber is simple in Comparative Example 1 that does not contain fibers and the superabsorbent resin previously prepared as described above. It can be seen that it shows a significantly improved absorption rate compared to the mixed comparative example 2.

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Abstract

The present invention relates to a super absorbent polymer preparation method. More particularly, the invention relates to a super absorbent polymer preparation method capable of preparing a super absorbent polymer that exhibits an improved absorption rate while maintaining excellent fundamental absorption properties such as centrifuge retention capacity.

Description

고흡수성 수지 및 이의 제조 방법Super absorbent polymer and method for manufacturing the same
관련 출원(들)과의 상호 인용Cross-citation with relevant application(s)
본 출원은 2018년 12월 11일자 한국 특허 출원 제10-2018-0158919호 및 2019년 11월 4일자 한국 특허 출원 제10-2019-0139625호에 기초한 우선권의 이익을 주장하며, 해당 한국 특허 출원의 문헌에 개시된 모든 내용은 본 명세서의 일부로서 포함된다.This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0158919 filed on December 11, 2018 and Korean Patent Application No. 10-2019-0139625 filed on November 4, 2019. All content disclosed in the literature is incorporated as part of this specification.
본 발명은 고흡수성 수지 및 이의 제조방법에 관한 것이다. 보다 자세하게는 기본적인 흡수능이 우수하면서도 흡수 속도가 향상된 고흡수성 수지의 제조 방법에 관한 것이다.The present invention relates to a super absorbent polymer and a method for manufacturing the same. More particularly, the present invention relates to a method for producing a super absorbent polymer having excellent basic absorption ability and improved absorption rate.
고흡수성 수지(Super Absorbent Polymer, SAP)란 자체 무게의 5백 내지 1천 배 정도의 수분을 흡수할 수 있는 기능을 가진 합성 고분자 물질로, 생리용구로 실용화되기 시작해서, 현재는 어린이용 종이 기저귀 등 위생용품 외에 원예용 토양보수제, 토목, 건축용 지수재, 육묘용 시트, 식품 유통분야에서의 신선도 유지제, 및 찜질용 등의 재료로 널리 사용되고 있다.Super Absorbent Polymer (SAP) is a synthetic polymer material that has the ability to absorb about 500 to 1,000 times its own weight, and has started to be put into practical use as a physiological tool. In addition to sanitary products such as gardening, it has been widely used as a material for soil repair agents for gardening, civil engineering, construction water supply materials, sheets for raising seedlings, freshness preservatives in the food distribution field, and poultices.
가장 많은 경우에, 이러한 고흡수성 수지는 기저귀나 생리대 등 위생재 분야에서 널리 사용되고 있는데, 이러한 용도를 위해 수분 등에 대한 높은 흡수력을 나타낼 필요가 있고, 외부의 압력에도 흡수된 수분이 빠져 나오지 않는 등의 우수한 흡수 특성을 나타낼 필요가 있다. 또한, 최근 들어서는 수분 등 목표 용액을 보다 빠르게 흡수 및 저장하는 흡수 속도가 더욱 요구되고 있다. 기본적으로 수계 용액에 대한 고흡수성 수지의 흡수는 수지 표면에서 일어나므로, 흡수 속도를 향상시키기 위해서는 고흡수성 수지의 표면적을 넓히는 방법이 고려될 수 있다. 이에 따라, 이전부터 고흡수성 수지의 입도를 감소시키거나, 다공성 구조를 형성하는 방법 등이 흡수 속도를 높이기 위한 방법으로 고려된 바 있다.In most cases, these superabsorbent polymers are widely used in the field of sanitary materials such as diapers and sanitary napkins. For this purpose, it is necessary to exhibit high absorbency for moisture, etc., and absorbed moisture does not come out even under external pressure. It is necessary to exhibit excellent absorption properties. In addition, in recent years, an absorption rate for absorbing and storing a target solution such as moisture more rapidly is further required. Basically, the absorption of the superabsorbent polymer into the aqueous solution occurs at the resin surface, so a method of increasing the surface area of the superabsorbent polymer can be considered to improve the absorption rate. Accordingly, a method for reducing the particle size of the super absorbent polymer or forming a porous structure has been considered as a method for increasing the absorption rate.
일례로, 고흡수성 수지에 다공성 구조를 형성하기 위하여 발포제를 첨가하여 고흡수성 수지를 제조하는 방법이 제안되었다. 그러나 발포제의 함량이 높을수록 흡수 속도는 일정 수준까지 개선되지만, 과다한 발포로 인해 고흡수성 수지의 미분 발생량이 증가하며, 겔 강도가 저하되는 문제가 있다. 또한, 고흡수성 수지는 입도가 감소함에 따라 기본적인 흡수 특성이 감소하는 경향이 있다. 이에, 기존에 알려진 방법으로는 기본적인 흡수능을 유지하면서도 흡수 속도를 향상시키는 데 한계가 있었다.As an example, a method of manufacturing a superabsorbent polymer by adding a blowing agent to form a porous structure in a superabsorbent polymer has been proposed. However, the higher the content of the blowing agent, the absorption rate is improved to a certain level, but due to excessive foaming, the amount of fine powder generated in the super absorbent polymer increases, and there is a problem that the gel strength is lowered. In addition, the superabsorbent polymer tends to have reduced basic absorption characteristics as the particle size decreases. Thus, the known method has a limitation in improving the absorption rate while maintaining the basic absorption capacity.
본 발명은 상기와 같은 종래 기술의 문제점을 해결하기 위한 것으로, 보수능(CRC)과 같은 기본적인 흡수 성능이 우수하면서, 개선된 초기 흡수 속도를 나타내는 고흡수성 수지의 제조방법을 제공하기 위한 것이다.The present invention is to solve the problems of the prior art as described above, and to provide a method of manufacturing a super absorbent polymer exhibiting improved initial absorption rate while having excellent basic absorption performance such as water retention capacity (CRC).
상기 목적을 달성하기 위하여 본 발명은,The present invention to achieve the above object,
a) 수용성 에틸렌계 불포화 단량체, 내부 가교제, 및 중합개시제를 혼합하여 모노머 조성물을 제조하는 단계;a) preparing a monomer composition by mixing a water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator;
b) 상기 모노머 조성물을 중합하여 함수겔상 중합체를 제조하는 단계;b) polymerizing the monomer composition to prepare a hydrogel polymer;
c) 상기 함수겔상 중합체를 다지는 단계;c) compacting the hydrogel polymer;
d) 상기 다져진 함수겔상 중합체에 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 첨가하고 혼합하여 혼합물을 제조하는 단계;d) adding and mixing one or more kinds of fluff pulp and synthetic polymer fibers to the compacted hydrogel polymer to prepare a mixture;
e) 상기 혼합물을 다지는 단계;e) compacting the mixture;
f) 상기 혼합물을 건조하는 단계; 및f) drying the mixture; And
g) 상기 혼합물을 분쇄하는 단계를 포함하는 고흡수성 수지의 제조방법을 제공한다.g) It provides a method for producing a super absorbent polymer comprising the step of grinding the mixture.
상기 섬유는 함수겔상 중합체 100 중량부에 대하여 1 내지 18 중량부로 포함될 수 있다.The fiber may be included in 1 to 18 parts by weight based on 100 parts by weight of the hydrogel polymer.
상기 섬유의 길이는 1 내지 20 mm일 수 있다.The length of the fiber may be 1 to 20 mm.
상기 섬유의 너비는 1 내지 100 ㎛일 수 있다.The width of the fiber may be 1 to 100 ㎛.
일 구현예에서, 상기 c) 내지 e) 단계 중 1 이상의 단계에서 물을 더 첨가할 수 있다. 이때, 상기 물은 함수겔상 중합체 100 중량부에 대하여 1 내지 20 중량부로 첨가될 수 있다.In one embodiment, water may be further added in at least one of steps c) to e). At this time, the water may be added in 1 to 20 parts by weight based on 100 parts by weight of the hydrogel polymer.
일 구현예에서, 상기 모노머 조성물은 발포제를 더 포함할 수 있다. 이때, 상기 모노머 조성물은 알킬 설페이트 염 (alkyl sulfate salt), 알킬 설포네이트 염 (alkyl sulfonate salt), 알킬 포스페이트 염 (alkyl phosphate salt), 알킬 카보네이트 염 (alkyl carbonate salt), 폴리에틸렌 글리콜 알킬 에스테르 (polyethylene glycol alkyl ester), 폴리프로필렌 글리콜 알킬 에스테르 (polypropylene glycol alkyl ester), 글루코사이드 알킬 에스테르 (glucoside alkyl ester), 글리세를 알킬 에스테르 (glycerol alkyl ester), 및 폴리에틸렌 글리콜과 폴리프로필렌 글리콜의 블록-공중합체 (block-copolymers of polyethylene glycol and polypropylene glycol)로 이루어지는 군에서 선택되는 1종 이상의 발포 안정제를 더 포함할 수 있다.In one embodiment, the monomer composition may further include a blowing agent. At this time, the monomer composition is alkyl sulfate salt (alkyl sulfate salt), alkyl sulfonate salt (alkyl sulfonate salt), alkyl phosphate salt (alkyl phosphate salt), alkyl carbonate salt (alkyl carbonate salt), polyethylene glycol alkyl ester (polyethylene glycol alkyl esters, polypropylene glycol alkyl esters, glucoside alkyl esters, glycerol alkyl esters, and block-copolymers of polyethylene glycol and polypropylene glycol (block- copolymers of polyethylene glycol and polypropylene glycol) may further include one or more foam stabilizers.
일 구현예에서, 상기 g) 단계 이후,In one embodiment, after step g),
h) 상기 g) 단계에서 얻어진 혼합물에 표면 가교제를 첨가하는 단계; 및h) adding a surface crosslinking agent to the mixture obtained in step g); And
i) 표면 가교 반응을 진행하는 단계를 더 포함할 수 있다.i) may further include the step of proceeding the surface crosslinking reaction.
이때, 상기 표면 가교제는 다가 알콜 화합물; 에폭시 화합물; 폴리아민 화합물; 할로에폭시 화합물; 할로에폭시 화합물의 축합 산물; 옥사졸린 화합물; 모노-, 디- 또는 폴리옥사졸리디논 화합물; 환상 우레아 화합물; 다가금속염; 및 알킬렌 카보네이트 화합물로 이루어진 군으로 이루어진 군에서 선택되는 1종 이상일 수 있다.At this time, the surface crosslinking agent is a polyhydric alcohol compound; Epoxy compounds; Polyamine compounds; Halo epoxy compounds; Condensation products of haloepoxy compounds; Oxazoline compounds; Mono-, di- or polyoxazolidinone compounds; Cyclic urea compounds; Polyvalent metal salts; And it may be one or more selected from the group consisting of alkylene carbonate compounds.
상기 표면 가교제는 상기 혼합물 100 중량부에 대하여 0.001 내지 5 중량부로 첨가될 수 있다.The surface crosslinking agent may be added in an amount of 0.001 to 5 parts by weight based on 100 parts by weight of the mixture.
한편, 본 발명은 상기 제조방법에 의하여 제조되는 고흡수성 수지를 제공한다.On the other hand, the present invention provides a super absorbent polymer produced by the above manufacturing method.
구체적으로, 본 발명은 수용성 에틸렌계 불포화 단량체가 내부 가교제의 존재 하에 가교 중합된 가교 중합체, 및 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 포함하는 베이스 수지 입자; 및Specifically, the present invention is a crosslinked polymer in which a water-soluble ethylenically unsaturated monomer is crosslinked and polymerized in the presence of an internal crosslinking agent, and base resin particles comprising at least one fiber among fluff pulp and synthetic polymer fibers; And
상기 베이스 수지 입자의 표면에 형성되어 있고, 상기 가교 중합체가 표면 가교제를 매개로 추가 가교된 표면 가교층을 포함하는 고흡수성 수지로서,It is formed on the surface of the base resin particles, the crosslinked polymer is a super absorbent polymer comprising a surface crosslinking layer further crosslinked via a surface crosslinking agent,
상기 섬유의 적어도 일부는 상기 베이스 수지 입자의 내부를 관통하여 혼입되어 있는 것인, 고흡수성 수지를 제공한다.Provides a super absorbent polymer, wherein at least a part of the fibers are mixed through the interior of the base resin particles.
상기 고흡수성 수지는 EDANA 법 WSP 241.3에 따라 측정한 원심분리 보수능(CRC)이 25 내지 45 g/g일 수 있다.The superabsorbent polymer may have a centrifugal water retention capacity (CRC) of 25 to 45 g/g measured according to EDANA method WSP 241.3.
상기 고흡수성 수지는 EDANA 법 WSP 242.3에 따라 측정한 0.3 psi의 가압 흡수능(AUL)이 25 내지 40 g/g일 수 있다.The superabsorbent polymer may have a pressure absorption capacity (AUL) of 0.3 psi measured according to EDANA method WSP 242.3 of 25 to 40 g/g.
또한, 본 발명의 일 구현예에 따르면,In addition, according to an embodiment of the present invention,
고흡수성 수지 입자; 및Superabsorbent resin particles; And
플러프 펄프 및 합성 고분자 섬유 중 1종 이상의 섬유를 포함하며,Contains at least one fiber among fluff pulp and synthetic polymer fibers,
상기 섬유의 적어도 일부는 상기 고흡수성 수지 입자의 내부를 관통하며 혼입되어 있는 것인, 고흡수성 수지 조성물이 제공된다.At least a portion of the fibers are penetrated through the interior of the superabsorbent polymer particles, the superabsorbent polymer composition is provided.
본 발명에 따른 고흡수성 수지의 제조방법에 의하면, 종래의 원심분리 보수능 등 기본적인 흡수 성능이 우수하면서도 개선된 흡수 속도를 나타내는 고품질의 고흡수성 수지를 제공할 수 있다.According to the method for producing a super absorbent polymer according to the present invention, it is possible to provide a high quality super absorbent polymer having excellent basic absorbent performance such as centrifugal water retention capacity and exhibiting improved absorbent speed.
또, 본 발명의 고흡수성 수지의 제조방법은 공정 단계가 비교적 간단하여 효율성이 높으며, 흡수 속도가 높은 고흡수성 수지를 수득할 수 있다.In addition, the manufacturing method of the super absorbent polymer of the present invention is relatively simple because the process steps are high, it is possible to obtain a super absorbent polymer having a high absorption rate.
도 1은 실시예 1에서 제조된 고흡수성 수지의 주사전자현미경(SEM) 사진이다.1 is a scanning electron microscope (SEM) photograph of the super absorbent polymer prepared in Example 1.
도 2는 비교예 2에서 제조된 고흡수성 수지의 SEM 사진이다.2 is a SEM photograph of the super absorbent polymer prepared in Comparative Example 2.
본 명세서에서 사용되는 용어는 단지 예시적인 실시예들을 설명하기 위해 사용된 것으로, 본 발명을 한정하려는 의도는 아니다. 단수의 표현은 문맥상 명백하게 다르게 뜻하지 않는 한, 복수의 표현을 포함한다. 본 명세서에서, "포함하다", "구비하다" 또는 "가지다" 등의 용어는 실시된 특징, 단계, 구성 요소 또는 이들을 조합한 것이 존재함을 지정하려는 것이지, 하나 또는 그 이상의 다른 특징들이나 단계, 구성 요소, 또는 이들을 조합한 것들의 존재 또는 부가 가능성을 미리 배제하지 않는 것으로 이해되어야 한다.The terminology used herein is only used to describe exemplary embodiments, and is not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, the terms "include", "have" or "have" are intended to indicate that an implemented feature, step, component or combination thereof exists, one or more other features or steps, It should be understood that the possibility of the presence or addition of components, or combinations thereof, is not excluded in advance.
본 발명은 다양한 변경을 가할 수 있고 여러 가지 형태를 가질 수 있는 바, 특정 실시예들을 예시하고 하기에서 상세하게 설명하고자 한다. 그러나, 이는 본 발명을 특정한 개시 형태에 대해 한정하려는 것이 아니며, 본 발명의 사상 및 기술 범위에 포함되는 모든 변경, 균등물 내지 대체물을 포함하는 것으로 이해되어야 한다.The present invention can be applied to various changes and may have various forms, and specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to a specific disclosure form, and it should be understood that it includes all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.
이하, 발명의 구체적인 구현예에 따라 고흡수성 수지 및 이의 제조 방법에 대해 보다 상세히 설명하기로 한다.Hereinafter, a super absorbent polymer and a method for manufacturing the same according to specific embodiments of the present invention will be described in more detail.
본 발명의 일 구현예에 따른 고흡수성 수지의 제조 방법은,Method of manufacturing a super absorbent polymer according to an embodiment of the present invention,
a) 수용성 에틸렌계 불포화 단량체, 내부 가교제, 및 중합개시제를 혼합하여 모노머 조성물을 제조하는 단계;a) preparing a monomer composition by mixing a water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator;
b) 상기 모노머 조성물을 중합하여 함수겔상 중합체를 제조하는 단계;b) polymerizing the monomer composition to prepare a hydrogel polymer;
c) 상기 함수겔상 중합체를 다지는 단계;c) compacting the hydrogel polymer;
d) 상기 다져진 함수겔상 중합체에 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 첨가하고 혼합하여 혼합물을 제조하는 단계;d) adding and mixing one or more kinds of fluff pulp and synthetic polymer fibers to the compacted hydrogel polymer to prepare a mixture;
e) 상기 혼합물을 다지는 단계;e) compacting the mixture;
f) 상기 혼합물을 건조하는 단계; 및f) drying the mixture; And
g) 상기 혼합물을 분쇄하는 단계를 포함한다.g) grinding the mixture.
본 발명에서는 고흡수성 수지의 기본적인 흡수 성능을 유지하면서 우수한 흡수 속도를 구현하기 위하여, 함수겔상 중합체를 다지는 단계에서 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 첨가한다. 이와 같이 제조된 고흡수성 수지는 표면에 흡수능이 우수한 섬유가 흡착되어 있어, 기존의 고흡수성 수지와 비교하여 개선된 흡수 속도를 나타낸다. 이에, 본 발명에 따라 제조된 고흡수성 수지는 보수능과 같은 기본적인 흡수 물성이 유지되면서도, 더욱 향상된 흡수 속도를 나타낼 수 있다.In the present invention, one or more fibers of fluff pulp and synthetic polymer fibers are added in the step of compacting the hydrogel polymer in order to realize an excellent absorption rate while maintaining the basic absorption performance of the super absorbent polymer. The superabsorbent polymer prepared as described above exhibits an improved absorption rate compared to the existing superabsorbent polymer because fibers having excellent absorbent capacity are adsorbed on the surface. Thus, the superabsorbent polymer prepared according to the present invention can exhibit a more improved absorption rate while maintaining basic absorbent properties such as water retention capacity.
먼저, a) 수용성 에틸렌계 불포화 단량체, 내부 가교제 및 중합개시제를 혼합하여 모노머 조성물을 제조한다.First, a) a water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator are mixed to prepare a monomer composition.
상기 수용성 에틸렌계 불포화 단량체는 고흡수성 수지의 제조에 통상 사용되는 임의의 단량체를 별다른 제한없이 사용할 수 있다. 여기에는 음이온성 단량체와 그 염, 비이온계 친수성 함유 단량체 및 아미노기 함유 불포화 단량체 및 그의 4급화물로 이루어진 군에서 선택되는 어느 하나 이상의 단량체를 사용할 수 있다.As the water-soluble ethylenically unsaturated monomer, any monomer commonly used in the production of superabsorbent polymers can be used without particular limitation. Any one or more monomers selected from the group consisting of anionic monomers and salts thereof, nonionic hydrophilic-containing monomers and amino group-containing unsaturated monomers and quaternaries thereof can be used.
구체적으로는 (메타)아크릴산, 무수말레인산, 푸말산, 크로톤산, 이타콘산, 2-아크릴로일에탄 술폰산, 2-메타아크릴로일에탄술폰산, 2-(메타)아크릴로일프로판술폰산 또는 2-(메타)아크릴아미드-2-메틸 프로판 술폰산의 음이온성 단량체와 그 염; (메타)아크릴아미드, N-치환(메타)아크릴레이트, 2-히드록시에틸(메타)아크릴레이트, 2-히드록시프로필(메타)아크릴레이트, 메톡시폴리에틸렌글리콜(메타)아크릴레이트 또는 폴리에틸렌 글리콜(메타)아크릴레이트의 비이온계 친수성 함유 단량체; 및 (N,N)-디메틸아미노에틸(메타) 아크릴레이트 또는 (N,N)-디메틸아미노프로필(메타)아크릴아미드의 아미노기 함유 불포화 단량체 및 그의 4급화물로 이루어진 군에서 선택된 어느 하나 이상을 사용할 수 있다.Specifically, (meth)acrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethanesulfonic 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, methoxypolyethylene glycol (meth)acrylate or polyethylene glycol ( Nonionic hydrophilic monomers of meth)acrylate; And an amino group-containing unsaturated monomer of (N,N)-dimethylaminoethyl (meth) acrylate or (N,N)-dimethylaminopropyl (meth)acrylamide, and quaternaries thereof. Can be.
더욱 바람직하게는 아크릴산 또는 그 염, 예를 들어, 아크릴산 또는 그 나트륨염 등의 알칼리 금속염을 사용할 수 있는데, 이러한 단량체를 사용하여 보다 우수한 물성을 갖는 고흡수성 수지의 제조가 가능해 진다. 상기 아크릴산의 알칼리 금속염을 단량체로 사용하는 경우, 아크릴산을 가성소다(NaOH)와 같은 염기성 화합물로 중화시켜 사용할 수 있다.More preferably, an acrylic acid or a salt thereof, for example, an alkali metal salt such as acrylic acid or a sodium salt thereof may be used, and the use of such a monomer makes it possible to manufacture a super absorbent polymer having better physical properties. When the alkali metal salt of acrylic acid is used as a monomer, it can be used by neutralizing acrylic acid with a basic compound such as caustic soda (NaOH).
상기 수용성 에틸렌계 불포화 단량체의 농도는, 상기 고흡수성 수지의 원료 물질 및 용매를 포함하는 단량체 조성물에 대해 약 20 내지 약 60 중량%, 바람직하게는 약 40 내지 약 50 중량%로 될 수 있으며, 중합 시간 및 반응 조건 등을 고려해 적절한 농도로 될 수 있다. 다만, 상기 단량체의 농도가 지나치게 낮아지면 고흡수성 수지의 수율이 낮고 경제성에 문제가 생길 수 있고, 반대로 농도가 지나치게 높아지면 단량체의 일부가 석출되거나 중합된 함수겔상 중합체의 분쇄 시 분쇄 효율이 낮게 나타나는 등 공정상 문제가 생길 수 있으며 고흡수성 수지의 물성이 저하될 수 있다.The concentration of the water-soluble ethylenically unsaturated monomer may be about 20 to about 60% by weight, preferably about 40 to about 50% by weight, with respect to the monomer composition containing the raw material and solvent of the superabsorbent polymer, and polymerization It may be an appropriate concentration in consideration of time and reaction conditions. However, if the concentration of the monomer is too low, the yield of the superabsorbent polymer may be low and economic problems may occur. Conversely, if the concentration is too high, a part of the monomer precipitates or the grinding efficiency of the polymerized hydrogel polymer is low. Such problems may occur in the process and physical properties of the super absorbent polymer may be deteriorated.
본 발명의 고흡수성 수지 제조 방법에서 중합시 사용되는 중합 개시제는 고흡수성 수지의 제조에 일반적으로 사용되는 것이면 특별히 한정되지 않는다.The polymerization initiator used in polymerization in the superabsorbent polymer production method of the present invention is not particularly limited as long as it is generally used for the production of superabsorbent polymers.
구체적으로, 상기 중합 개시제는 중합 방법에 따라 열중합 개시제 또는 UV 조사에 따른 광중합 개시제를 사용할 수 있다. 다만 광중합 방법에 의하더라도, 자외선 조사 등의 조사에 의해 일정량의 열이 발생하고, 또한 발열 반응인 중합 반응의 진행에 따라 어느 정도의 열이 발생하므로, 추가적으로 열중합 개시제를 포함할 수도 있다.Specifically, the polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator according to UV irradiation depending on the polymerization method. However, even by the photopolymerization method, since a certain amount of heat is generated by irradiation with ultraviolet rays or the like and a certain amount of heat is generated as the polymerization reaction that is an exothermic reaction proceeds, a thermal polymerization initiator may be additionally included.
상기 광중합 개시제는 자외선과 같은 광에 의해 라디칼을 형성할 수 있는 화합물이면 그 구성의 한정이 없이 사용될 수 있다.If the photopolymerization initiator is a compound capable of forming radicals by light such as ultraviolet rays, the composition may be used without limitation.
상기 광중합 개시제로는 예를 들어, 벤조인 에테르(benzoin ether), 디알킬아세토페논(dialkyl acetophenone), 하이드록실 알킬케톤(hydroxyl alkylketone), 페닐글리옥실레이트(phenyl glyoxylate), 벤질디메틸케탈(Benzyl dimethyl ketal), 아실포스핀(acyl phosphine) 및 알파-아미노케톤(α-aminoketone)으로 이루어진 군에서 선택되는 하나 이상을 사용할 수 있다. 한편, 아실포스핀의 구체예로, 상용하는 lucirin TPO, 즉, 2,4,6-트리메틸-벤조일-트리메틸 포스핀 옥사이드(2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide)를 사용할 수 있다. 보다 다양한 광개시제에 대해서는 Reinhold Schwalm 저서인 "UV Coatings: Basics, Recent Developments and New Application(Elsevier 2007년)" p. 115에 잘 명시되어 있으며, 상술한 예에 한정되지 않는다.The photopolymerization initiator includes, for example, benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketal. ketal), acyl phosphine, and alpha-aminoketone (α-aminoketone). Meanwhile, as a specific example of acylphosphine, a 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. . For more photoinitiators, Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007)" p. It is well specified in 115, and is not limited to the example described above.
상기 광중합 개시제는 상기 모노머 조성물에 대하여 약 0.01 내지 약 1.0 중량%의 농도로 포함될 수 있다. 이러한 광중합 개시제의 농도가 지나치게 낮을 경우 중합 속도가 느려질 수 있고, 광중합 개시제의 농도가 지나치게 높으면 고흡수성 수지의 분자량이 작고 물성이 불균일해질 수 있다.The photopolymerization initiator may be included in a concentration of about 0.01 to about 1.0% by weight relative to the monomer composition. If the concentration of the photopolymerization initiator is too low, the polymerization rate may be slow, and if the concentration of the photopolymerization initiator is too high, the molecular weight of the super absorbent polymer may be small and the properties may be uneven.
또한, 상기 열중합 개시제로는 과황산염계 개시제, 아조계 개시제, 과산화수소 및 아스코르빈산으로 이루어진 개시제 군에서 선택되는 하나 이상을 사용할 수 있다. 구체적으로, 과황산염계 개시제의 예로는 과황산나트륨(Sodium persulfate; Na2S2O8), 과황산칼륨(Potassium persulfate; K2S2O8), 과황산암모늄(Ammonium persulfate;(NH4)2S2O8) 등이 있으며, 아조(Azo)계 개시제의 예로는 2, 2-아조비스-(2-아미디노프로판)이염산염(2, 2-azobis(2-amidinopropane) dihydrochloride), 2, 2-아조비스-(N, N-디메틸렌)이소부티라마이딘 디하이드로클로라이드(2,2-azobis-(N, N-dimethylene)isobutyramidine dihydrochloride), 2-(카바모일아조)이소부티로니트릴(2-(carbamoylazo)isobutylonitril), 2, 2-아조비스[2-(2-이미다졸린-2-일)프로판] 디하이드로클로라이드(2,2-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride), 4,4-아조비스-(4-시아노발레릭 산)(4,4-azobis-(4-cyanovaleric acid)) 등이 있다. 보다 다양한 열중합 개시제에 대해서는 Odian 저서인 'Principle of Polymerization(Wiley, 1981)', p. 203에 잘 명시되어 있으며, 상술한 예에 한정되지 않는다.In addition, as the thermal polymerization initiator, one or more selected from the initiator group consisting of a persulfate-based initiator, an azo-based initiator, hydrogen peroxide, and ascorbic acid may be used. Specifically, examples of the persulfate-based initiator are sodium persulfate (Na 2 S 2 O 8 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate (Ammonium persulfate; (NH 4 ) 2 S 2 O 8 ), and examples of the azo-based initiator are 2, 2-azobis-(2-amidinopropane) dihydrochloride (2, 2-azobis (2-amidinopropane) dihydrochloride), 2 , 2-azobis-(N, N-dimethylene)isobutyramidine dihydrochloride (2-azobis-(N,N-dimethylene)isobutyramidine 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-azobis-(4-cyanovaleric acid) (4,4-azobis-(4-cyanovaleric acid)). For more various thermal polymerization initiators, Odian's book'Principle of Polymerization (Wiley, 1981)', p. It is well specified in 203, and is not limited to the above-described example.
상기 열중합 개시제는 상기 모노머 조성물에 대하여 약 0.001 내지 약 0.5 중량%의 농도로 포함될 수 있다. 이러한 열 중합 개시제의 농도가 지나치게 낮을 경우 추가적인 열중합이 거의 일어나지 않아 열중합 개시제의 추가에 따른 효과가 미미할 수 있고, 열중합 개시제의 농도가 지나치게 높으면 고흡수성 수지의 분자량이 작고 물성이 불균일해질 수 있다.The thermal polymerization initiator may be included in a concentration of about 0.001 to about 0.5% by weight relative to the monomer composition. If the concentration of the thermal polymerization initiator is too low, the additional thermal polymerization hardly occurs, so the effect of the addition of the thermal polymerization initiator may be negligible. If the concentration of the thermal polymerization initiator is too high, the molecular weight of the super absorbent polymer is small and the physical properties may be uneven. have.
상기 내부 가교제로는 상기 수용성 에틸렌계 불포화 단량체의 수용성 치환기와 반응할 수 있는 관능기를 1개 이상 가지면서, 에틸렌성 불포화기를 1개 이상 갖는 가교제; 혹은 상기 단량체의 수용성 치환기 및/또는 단량체의 가수분해에 의해 형성된 수용성 치환기와 반응할 수 있는 관능기를 2개 이상 갖는 가교제를 사용할 수 있다.As the internal crosslinking agent, while having at least one functional group capable of reacting with the water-soluble substituent of the water-soluble ethylenically unsaturated monomer, a crosslinking agent having at least one ethylenically unsaturated group; Alternatively, a crosslinking agent having two or more functional groups capable of reacting with the water-soluble substituent of the monomer and/or the water-soluble substituent formed by hydrolysis of the monomer may be used.
상기 내부 가교제의 구체적인 예로는, 탄소수 8 내지 12의 비스아크릴아미드, 비스메타아크릴아미드, 탄소수 2 내지 10의 폴리올의 폴리(메타)아크릴레이트 또는 탄소수 2 내지 10의 폴리올의 폴리(메타)알릴에테르 등을 들 수 있고, 보다 구체적으로, N,N'-메틸렌비스(메타)아크릴레이트, 에틸렌옥시(메타)아크릴레이트, 폴리에틸렌옥시(메타)아크릴레이트, 프로필렌옥시(메타)아크릴레이트, 글리세린 디아크릴레이트, 글리세린 트리아크릴레이트, 트리메티롤 트리아크릴레이트, 트리알릴아민, 트리아릴시아누레이트, 트리알릴이소시아네이트, 폴리에틸렌글리콜, 디에틸렌글리콜 및 프로필렌글리콜로 이루어진 군에서 선택된 하나 이상을 사용할 수 있다.Specific examples of the internal crosslinking agent include bisacrylamide having 8 to 12 carbons, bismethacrylamide, poly(meth)acrylate of polyols having 2 to 10 carbons, or poly(meth)allyl ether of polyols having 2 to 10 carbons, etc. And more specifically, N,N'-methylenebis(meth)acrylate, ethyleneoxy(meth)acrylate, polyethyleneoxy(meth)acrylate, propyleneoxy(meth)acrylate, glycerin diacrylate , Glycerin triacrylate, trimethyrol triacrylate, triallylamine, triaryl cyanurate, triallyl isocyanate, polyethylene glycol, diethylene glycol and propylene glycol.
또한, 상기 내부 가교제로는 에폭시기를 1 이상 포함하는 에폭시 화합물을 사용할 수 있다. 이때, 상기 에폭시 화합물은 에폭시기 외에 수용성 에틸렌계 불포화 단량체와 반응할 수 있는 관능기를 1 이상 더 포함할 수도 있다. 구체적인 예로는, 에틸렌글리콜 디글리시딜 에테르, 폴리에틸렌글리콜 디글리시딜 에테르, 글리세롤 폴리글리시딜 에테르, 프로필렌글리콜 디글리시딜 에테르 또는 폴리프로필렌 글리콜 디글리시딜 에테르 등의 다가 에폭시계 화합물을 들 수 있다.In addition, an epoxy compound containing one or more epoxy groups may be used as the internal crosslinking agent. In this case, the epoxy compound may further include at least one functional group capable of reacting with the water-soluble ethylenically unsaturated monomer in addition to the epoxy group. Specific examples include polyhydric epoxy compounds such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, propylene glycol diglycidyl ether, or polypropylene glycol diglycidyl ether. Can be lifted.
이러한 내부 가교제는 2 이상 조합되어 사용 가능하며, 상기 모노머 조성물에 대하여 약 0.01 내지 약 0.5 중량%의 농도로 포함되어, 중합된 고분자를 가교시킬 수 있다.These internal crosslinking agents may be used in combination of two or more, and included in a concentration of about 0.01 to about 0.5% by weight relative to the monomer composition to crosslink the polymerized polymer.
한편, 본 발명의 제조방법에서, 상기 모노머 조성물은 필요에 따라 발포제, 발포 안정제, 증점제(thickener), 가소제, 보존안정제, 산화방지제 등의 첨가제를 더 포함할 수 있다.Meanwhile, in the manufacturing method of the present invention, the monomer composition may further include additives such as a foaming agent, a foaming stabilizer, a thickener, a plasticizer, a preservative stabilizer, and an antioxidant, if necessary.
상기 발포제는 당 업계에서 통상 사용되는 무기 발포제 및 캡슐화된 발포제가 제한 없이 사용될 수 있다.The blowing agent may be used without limitation, inorganic blowing agents and encapsulating blowing agents commonly used in the art.
상기 무기 발포제는 탄산칼슘(CaCO3), 중탄산나트륨(NaHCO3), 중탄산암모늄(NH4HCO3), 탄산암모늄((NH4)2CO3), 아질산암모늄(NH4NO2), 붕소화수소나트륨 (NaBH4) 및 탄산나트륨(Na2CO3) 중 선택되는 1종 이상이 사용 가능하나, 이에 제한되지 않는다.The inorganic blowing agent is calcium carbonate (CaCO 3 ), sodium bicarbonate (NaHCO 3 ), ammonium bicarbonate (NH 4 HCO 3 ), ammonium carbonate ((NH 4 ) 2 CO 3 ), ammonium nitrite (NH 4 NO 2 ), hydrogen borohydride One or more selected from sodium (NaBH 4 ) and sodium carbonate (Na 2 CO 3 ) may be used, but is not limited thereto.
상기 캡슐화된 발포제는 모노머 조성물의 중합시에는 캡슐화된 상태로 존재하다가, 후술하는 건조 공정 시 가해지는 열에 의해 발포하게 되며, 이에 따라 고흡수성 수지의 고분자 구조 사이사이에 적절한 크기의 기공을 형성하여 고흡수성 수지 시트가 열린 기공 채널(open pore channel)의 구조를 나타낼 수 있도록 한다. 따라서, 모노머 조성물에 캡슐화된 발포제를 포함하는 경우, 고흡수성 수지의 흡수 속도를 더욱 향상시킬 수 있어 바람직하다.The encapsulated foaming agent exists in an encapsulated state during polymerization of the monomer composition, and then foams by heat applied during the drying process described below, thereby forming pores of appropriate size between the polymer structures of the super absorbent polymer, It is possible for the absorbent resin sheet to exhibit the structure of an open pore channel. Therefore, when the foaming agent encapsulated in the monomer composition is included, the absorption rate of the superabsorbent polymer can be further improved, which is preferable.
상기 캡슐화된 발포제는 탄화수소를 포함하는 코어와 상기 코어를 둘러싸며 열가소성 수지로 형성되는 쉘을 포함하는 구조를 가질 수 있다. 이러한 캡슐화된 발포제는 상기 코어와 쉘을 이루는 성분과 각 성분의 중량, 직경에 따라 팽창 특성이 달라지며 이를 조절함으로써 원하는 크기로 팽창이 가능하며 상기 고흡수성 수지 시트의 다공성을 조절할 수 있다.The encapsulated foaming agent may have a structure including a core including a hydrocarbon and a shell surrounding the core and formed of a thermoplastic resin. The encapsulated foaming agent has different expansion characteristics depending on the weight and diameter of the components constituting the core and the shell, and can be expanded to a desired size by controlling it, and can control the porosity of the superabsorbent polymer sheet.
한편 원하는 크기의 기공이 형성되는지 여부를 파악하기 위해 먼저 캡슐화된 발포제의 팽창 특성을 파악할 필요가 있다. 그러나, 고흡수성 수지 내에서 캡슐화된 발포제가 발포된 형태는 고흡수성 수지의 제조 조건에 따라 달라질 수 있으므로 하나의 형태로 정의하기가 어렵다. 따라서, 먼저 캡슐화된 발포제를 공기 중에서 발포시켜 팽창 비율 및 크기를 확인함으로써, 원하는 기공을 형성하기에 적합한지 확인할 수 있다.Meanwhile, in order to determine whether pores of a desired size are formed, it is necessary to first grasp the expansion characteristics of the encapsulated blowing agent. However, the form in which the foaming agent encapsulated in the superabsorbent polymer is foamed may vary depending on the manufacturing conditions of the superabsorbent polymer, so it is difficult to define it as one form. Therefore, by first foaming the encapsulated foaming agent in the air, the expansion ratio and size can be checked to confirm whether it is suitable for forming desired pores.
구체적으로, 유리 페트리 접시 위에 캡슐화된 발포제를 도포한 뒤 공기 중에서 150 ℃의 열을 10 분 동안 가하여 캡슐화된 발포제를 팽창시킨다. 이때, 캡슐화된 발포제가 3 내지 15 배, 5 내지 15 배 혹은 8.5 내지 10 배의 공기 중에서의 최대 팽창 비율을 나타낼 때, 본 발명 고흡수성 수지 시트의 제조방법에 있어 적절한 열린 기공 구조를 형성하기에 적합한 것으로 판단할 수 있다.Specifically, after applying the encapsulated blowing agent on a glass petri dish, heat of 150° C. in air was applied for 10 minutes to expand the encapsulated blowing agent. At this time, when the encapsulated foaming agent exhibits a maximum expansion ratio in the air of 3 to 15 times, 5 to 15 times, or 8.5 to 10 times, to form an appropriate open pore structure in the method of manufacturing the superabsorbent polymer sheet of the present invention It can be judged as suitable.
상기 캡슐화된 발포제는 평균 직경이 5 내지 50 ㎛, 또는 5 내지 30 ㎛, 또는 5 내지 20 ㎛, 또는 7 내지 17 ㎛일 수 있다. 상기 캡슐화된 발포제가 상기와 같은 평균 직경을 나타낼 때 적절한 공극률을 달성하기에 적합한 것으로 판단할 수 있다.The encapsulated foaming agent may have an average diameter of 5 to 50 μm, or 5 to 30 μm, or 5 to 20 μm, or 7 to 17 μm. When the encapsulated foaming agent exhibits such an average diameter, it can be judged to be suitable for achieving an appropriate porosity.
또한, 상기 캡슐화된 발포제가 공기 중에서의 20 내지 190 ㎛, 또는 50 내지 190 ㎛, 또는 70 내지 190 ㎛, 또는 75 내지 190 ㎛의 최대 팽창 직경을 나타낼 때 본 발명 고흡수성 수지 시트의 제조방법에 있어 적절한 열린 기공 구조를 형성하기에 적합한 것으로 판단할 수 있다.In addition, when the encapsulated foaming agent exhibits a maximum expansion diameter of 20 to 190 μm, or 50 to 190 μm, or 70 to 190 μm, or 75 to 190 μm in air, the method of manufacturing the superabsorbent polymer sheet according to the present invention It can be judged to be suitable for forming a suitable open pore structure.
캡슐화된 발포제의 공기 중에서의 최대 팽창 비율 및 최대 팽창 직경은 후술하는 제조예에서 보다 자세히 기술하기로 한다.The maximum expansion ratio and maximum expansion diameter in the air of the encapsulated blowing agent will be described in more detail in the preparation examples described below.
상기 캡슐화된 발포제의 코어를 구성하는 탄화수소는 n-프로판, n-부탄, iso-부탄, 사이클로부탄, n-펜탄, iso-펜탄, 사이클로펜탄, n-헥산, iso-헥산, 사이클로헥산, n-헵탄, iso-헵탄, 사이클로헵탄, n-옥탄, iso-옥탄 및 사이클로옥탄으로 구성된 군에서 선택된 1 종 이상일 수 있다. 이 중에서도 탄소수 3 내지 5의 탄화수소(n-프로판, n-부탄, iso-부탄, 사이클로부탄, n-펜탄, iso-펜탄, 사이클로펜탄)가 상술한 크기의 기공을 형성하기에 적합하고, iso-부탄이 가장 적합할 수 있다.The hydrocarbons constituting the core of the encapsulated blowing agent are n-propane, n-butane, iso-butane, cyclobutane, n-pentane, iso-pentane, cyclopentane, n-hexane, iso-hexane, cyclohexane, n- It may be one or more selected from the group consisting of heptane, iso-heptane, cycloheptane, n-octane, iso-octane and cyclooctane. Among these, hydrocarbons having 3 to 5 carbon atoms (n-propane, n-butane, iso-butane, cyclobutane, n-pentane, iso-pentane, cyclopentane) are suitable for forming pores of the size described above, and iso- Butane may be the most suitable.
그리고, 상기 캡슐화된 발포제의 쉘을 구성하는 열가소성 수지는 (메트)아크릴레이트, (메트)아크릴로니트릴, 방향족 비닐, 초산 비닐, 할로겐화 비닐 및 할로겐화 비닐리덴으로 구성된 군에서 선택된 1 종 이상의 모노머로부터 형성되는 폴리머일 수 있다. 이 중에서도 (메트)아크릴레이트 및 (메트)아크릴로니트릴의 공중합체가 상술한 크기의 기공을 형성하기에 가장 적합할 수 있다.In addition, the thermoplastic resin constituting the shell of the encapsulated foaming agent is formed from at least one monomer selected from the group consisting of (meth)acrylate, (meth)acrylonitrile, aromatic vinyl, vinyl acetate, vinyl halide, and vinylidene halide. It can be a polymer. Among them, a copolymer of (meth)acrylate and (meth)acrylonitrile may be most suitable for forming pores of the size described above.
상기 캡슐화된 발포제는 전체 캡슐화된 발포제 중량에 대하여 탄화수소를 10 내지 30 중량%로 포함할 수 있다. 이러한 범위 내에서 열린 기공 구조를 형성하는데 가장 적합할 수 있다.The encapsulated blowing agent may contain 10 to 30% by weight of hydrocarbons based on the total encapsulated blowing agent weight. It may be most suitable to form an open pore structure within this range.
상기 캡슐화된 발포제는 제조하여 사용하거나, 또는 상술한 조건을 만족하는 것으로 상용화된 발포제를 사용할 수 있다.The encapsulated foaming agent may be prepared and used, or a commercialized foaming agent satisfying the above-described conditions may be used.
또한 상기 캡슐화된 발포제의 함량은 수용성 에틸렌계 불포화 단량체의 100 중량부에 대하여 0.001 내지 10 중량부, 바람직하게는 0.01 내지 5 중량부, 더욱 바람직하게는 0.1 내지 1 중량부를 사용할 수 있다. 상기 캡슐화된 발포제의 함량이 지나치게 적으면, 열린 기공 구조 제대로 형성되지 않을 수 있고, 너무 많이 포함되는 경우, 다공성이 너무 높아 고흡수성 수지의 강도가 약해질 수 있으므로 이러한 관점에서 상기 함량 범위가 바람직할 수 있다.In addition, the content of the encapsulating foaming agent may be 0.001 to 10 parts by weight, preferably 0.01 to 5 parts by weight, and more preferably 0.1 to 1 part by weight based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. If the content of the encapsulated foaming agent is too small, the open pore structure may not be properly formed, and if it is contained too much, the porosity may be too high, so that the strength of the super absorbent polymer may be weak, so the content range is preferable in this respect. Can be.
상기 캡슐화된 발포제를 사용하는 경우, 안정적인 발포를 유도하기 위하여 모노머 조성물에는 발포 안정제를 더 포함할 수 있다.When using the encapsulated foaming agent, in order to induce stable foaming, the monomer composition may further include a foaming stabilizer.
상기 발포 안정제는 알킬 설페이트 염 (alkyl sulfate salt), 알킬 설포네이트 염 (alkyl sulfonate salt), 알킬 포스페이트 염 (alkyl phosphate salt), 알킬 카보네이트 염 (alkyl carbonate salt), 폴리에틸렌 글리콜 알킬 에스테르 (polyethylene glycol alkyl ester), 폴리프로필렌 글리콜 알킬 에스테르 (polypropylene glycol alkyl ester), 글루코사이드 알킬 에스테르 (glucoside alkyl ester), 글리세를 알킬 에스테르 (glycerol alkyl ester), 폴리에틸렌 글리콜과 폴리프로필렌 글리콜의 블록-공중합체 (block-copolymers of polyethylene glycol and polypropylene glycol) 또는 이들의 혼합물 등을 사용할 수 있다. 이때, 상기 알킬기는 특별히 한정되지 않으며, 탄소수 1 내지 30의 직쇄, 분지쇄 및 고리형 알킬기 등일 수 있다. 이러한 발포 안정제는 상기 모노머 조성물 100 중량% 중 약 0.0001 내지 0.1 중량 % 혹은 약 0.001 내지 0.1 중량 %의 농도로 포함되어 발포제의 발포 효율을 향상시켜 적절한 기공 구조를 갖는 가교 중합체를 형성하게 할 수 있다.The foam stabilizer is an alkyl sulfate salt, an alkyl sulfonate salt, an alkyl phosphate salt, an alkyl carbonate salt, and a polyethylene glycol alkyl ester. ), polypropylene glycol alkyl ester, glucoside alkyl ester, glycerol alkyl ester, block-copolymers of polyethylene glycol and polypropylene glycol glycol and polypropylene glycol) or mixtures thereof. In this case, the alkyl group is not particularly limited, and may be a straight chain, branched chain or cyclic alkyl group having 1 to 30 carbon atoms. The foaming stabilizer may be included in a concentration of about 0.0001 to 0.1% by weight or about 0.001 to 0.1% by weight in 100% by weight of the monomer composition to improve the foaming efficiency of the foaming agent to form a crosslinked polymer having an appropriate pore structure.
상술한 수용성 에틸렌계 불포화 단량체, 광중합 개시제, 열중합 개시제, 내부 가교제 및 첨가제와 같은 원료 물질은 용매에 용해된 모노머 조성물 용액의 형태로 준비될 수 있다.Raw materials such as the water-soluble ethylenically unsaturated monomer, photopolymerization initiator, thermal polymerization initiator, internal crosslinking agent, and additives described above may be prepared in the form of a solution of a monomer composition dissolved in a solvent.
이 때 사용할 수 있는 상기 용매는 상술한 성분들을 용해할 수 있으면 그 구성의 한정이 없이 사용될 수 있으며, 예를 들어 물, 에탄올, 에틸렌글리콜, 디에틸렌글리콜, 트리에틸렌글리콜, 1,4-부탄디올, 프로필렌글리콜, 에틸렌글리콜모노부틸에테르, 프로필렌글리콜모노메틸에테르, 프로필렌글리콜모노메틸에테르아세테이트, 메틸에틸케톤, 아세톤, 메틸아밀케톤, 시클로헥사논, 시클로펜타논, 디에틸렌글리콜모노메틸에테르, 디에틸렌글리콜에틸에테르, 톨루엔, 크실렌, 부틸로락톤, 카르비톨, 메틸셀로솔브아세테이트 및 N,N-디메틸아세트아미드 등에서 선택된 1종 이상을 조합하여 사용할 수 있다.The solvent that can be used at this time can be used without limitation of its composition as long as it can dissolve the above-mentioned components, for example, water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, Propylene glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl amyl ketone, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol Ethyl ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate and N,N-dimethylacetamide can be used in combination.
상기 용매는 모노머 조성물의 총 함량에 대하여 상술한 성분을 제외한 잔량으로 포함될 수 있다.The solvent may be included in the remaining amount excluding the above-mentioned components with respect to the total content of the monomer composition.
다음으로, b) 상기 모노머 조성물을 열중합 또는 광중합하여 함수겔상 중합체를 제조한다.Next, b) the monomer composition is thermally polymerized or photopolymerized to prepare a hydrogel polymer.
상기 모노머 조성물의 열중합 또는 광중합 방법은 통상 사용되는 중합 방법이면, 특별히 구성의 한정이 없다.The thermal polymerization or photopolymerization method of the monomer composition is not particularly limited as long as it is a commonly used polymerization method.
구체적으로, 중합 방법은 중합 에너지원에 따라 크게 열중합 및 광중합으로 나뉘며, 통상 열중합을 진행하는 경우, 니더(kneader)와 같은 교반축을 가진 반응기에서 진행될 수 있으며, 광중합을 진행하는 경우, 이동 가능한 컨베이어 벨트를 구비한 반응기에서 진행될 수 있으나, 상술한 중합 방법은 일 예이며, 본 발명은 상술한 중합 방법에 한정되지는 않는다.Specifically, the polymerization method is largely divided into thermal polymerization and photopolymerization according to the polymerization energy source, and in general, when performing thermal polymerization, it can be carried out in a reactor having a stirring axis such as a kneader, and when performing photopolymerization, it is movable Although it may be carried out in a reactor equipped with a conveyor belt, the polymerization method described above is an example, and the present invention is not limited to the polymerization method described above.
일 예로, 상술한 바와 같이 교반축을 구비한 니더(kneader)와 같은 반응기에, 열풍을 공급하거나 반응기를 가열하여 열중합을 하여 얻어진 함수겔상 중합체는 반응기에 구비된 교반축의 형태에 따라, 반응기 배출구로 배출되는 함수겔상 중합체는 수 센티미터 내지 수 밀리미터 형태일 수 있다. 구체적으로, 얻어지는 함수겔상 중합체의 크기는 주입되는 모노머 조성물의 농도 및 주입속도 등에 따라 다양하게 나타날 수 있는데, 통상 중량 평균 입경이 2 내지 50 mm인 함수겔상 중합체가 얻어질 수 있다.For example, as described above, a hydrogel polymer obtained by thermal polymerization by supplying hot air or heating a reactor to a reactor such as a kneader having a stirring shaft is used as a reactor outlet, depending on the type of the stirring shaft provided in the reactor. The discharged hydrogel polymer may be in the form of several centimeters to several millimeters. Specifically, the size of the hydrogel polymer obtained may vary depending on the concentration and injection speed of the monomer composition to be injected, and a hydrogel polymer having a weight average particle diameter of 2 to 50 mm can be usually obtained.
또한, 상술한 바와 같이 이동 가능한 컨베이어 벨트를 구비한 반응기에서 광중합을 진행하는 경우, 통상 얻어지는 함수겔상 중합체의 형태는 벨트의 너비를 가진 시트 상의 함수겔상 중합체일 수 있다. 이 때, 중합체 시트의 두께는 주입되는 단량체 조성물의 농도 및 주입속도에 따라 달라지나, 통상 약 0.5 내지 약 5cm의 두께를 가진 시트 상의 중합체가 얻어질 수 있도록 단량체 조성물을 공급하는 것이 바람직하다. 시트 상의 중합체의 두께가 지나치게 얇을 정도로 단량체 조성물을 공급하는 경우, 생산 효율이 낮아 바람직하지 않으며, 시트 상의 중합체 두께가 5cm를 초과하는 경우에는 지나치게 두꺼운 두께로 인해, 중합 반응이 전 두께에 걸쳐 고르게 일어나지 않을 수가 있다.In addition, when the photopolymerization is performed in a reactor equipped with a movable conveyor belt as described above, the shape of the hydrogel polymer usually obtained may be a hydrogel polymer on a sheet having a belt width. At this time, the thickness of the polymer sheet varies depending on the concentration and the injection rate 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. When the monomer composition is supplied to such an extent that the thickness of the polymer on the sheet is too thin, production efficiency is low, which is undesirable. When the thickness of the polymer on the sheet exceeds 5 cm, due to the excessively thick thickness, the polymerization reaction does not occur evenly over the entire thickness. It may not.
이때 이와 같은 방법으로 얻어진 함수겔상 중합체의 통상 함수율은 약 40 내지 약 80 중량%일 수 있다. 한편, 본 명세서 전체에서 "함수율"은 전체 함수겔상 중합체 중량에 대해 차지하는 수분의 함량으로 함수겔상 중합체의 중량에서 건조 상태의 중합체의 중량을 뺀 값을 의미한다. 구체적으로는, 적외선 가열을 통해 중합체의 온도를 올려 건조하는 과정에서 중합체 중의 수분증발에 따른 무게감소분을 측정하여 계산된 값으로 정의한다. 이때, 건조 조건은 상온에서 약 180℃까지 온도를 상승시킨 뒤 180℃에서 유지하는 방식으로 총 건조시간은 온도상승단계 5분을 포함하여 20분으로 설정하여, 함수율을 측정한다.At this time, the normal water content of the hydrogel polymer obtained in this way may be about 40 to about 80% by weight. On the other hand, in the present specification, "water content" refers to a value obtained by subtracting the weight of the polymer in a dry state from the weight of the hydrogel polymer as the content of moisture to the total weight of the hydrogel polymer. Specifically, it is defined as a calculated value by measuring the weight loss due to evaporation of water in the polymer during the drying process by raising the temperature of the polymer through infrared heating. At this time, the drying condition is a method of raising the temperature from room temperature to about 180°C and then maintaining it at 180°C. The total drying time is set to 20 minutes including 5 minutes of the temperature rise step to measure the water content.
다음으로, c) 상기 제조된 함수겔상 중합체를 다지는(chopping) 단계를 수행한다.Next, c) chopping the prepared hydrogel polymer.
이때, 사용되는 분쇄기는 구성의 한정은 없으나, 구체적으로, 수직형 절단기(Vertical pulverizer), 터보 커터(Turbo cutter), 터보 글라인더(Turbo grinder), 회전 절단식 분쇄기(Rotary cutter mill), 절단식 분쇄기(Cutter mill), 원판 분쇄기(Disc mill), 조각 파쇄기(Shred crusher), 파쇄기(Crusher), 초퍼(chopper) 및 원판식 절단기(Disc cutter)로 이루어진 분쇄 기기 군에서 선택되는 어느 하나를 포함할 수 있으나, 상술한 예에 한정되지는 않는다.At this time, the used grinder is not limited in configuration, but specifically, a vertical cutter (Vertical pulverizer), a turbo cutter (Turbo cutter), a turbo grinder (Turbo grinder), a rotary cutting mill (Rotary cutter mill), cutting Cutter mill, disc mill, shred crusher, crusher, chopper, and disc cutter However, it is not limited to the above-described example.
이때 c) 단계는 함수겔상 중합체의 입경이 약 2 내지 약 20mm가 되도록 수행될 수 있다.At this time, step c) may be performed so that the particle diameter of the hydrogel polymer is about 2 to about 20 mm.
입경이 2mm 미만으로 조분쇄하는 것은 함수겔상 중합체의 높은 함수율로 인해 기술적으로 용이하지 않으며, 또한 분쇄된 입자 간에 서로 응집되는 현상이 나타날 수도 있다. 한편, 입경이 20mm 초과로 조분쇄하는 경우, 추후 이루어지는 건조 단계의 효율 증대 효과가 미미할 수 있다.Coarse pulverization with a particle diameter of less than 2 mm is not technically easy due to the high water content of the hydrogel polymer, and there may also be a phenomenon in which the particles are aggregated with each other. On the other hand, when the particle size is roughly crushed to more than 20 mm, the effect of increasing the efficiency of the drying step to be performed later may be insignificant.
다음으로, d) 상기 다져진 함수겔상 중합체에 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 첨가하고 혼합하여, 혼합물을 제조하고, e) 상기 혼합물을 다시 다지는 단계를 수행한다.Next, d) adding and mixing one or more fibers of fluff pulp and synthetic polymer fibers to the compacted hydrogel polymer to prepare a mixture, e) performing a step of compacting the mixture again.
이와 같이 함수겔상 중합체를 다지는 단계에 섬유를 첨가하는 경우, 함수겔상 중합체 입자 표면에 흡착되어 있던 섬유가 쵸퍼에 의하여 입자 내부로 혼입될 수 있다. 이에 따라, 상기 섬유의 적어도 일부는 베이스 수지의 입자 내부를 관통하는 형태로 혼입되며, 베이스 수지 입자 내부 및 외부 모두에 섬유가 분포할 수 있다. 이와 같이 베이스 수지의 내부 및 외부에 분포하는 섬유는 모세관 작용을 통해 주위의 수분을 빠르게 흡수하여 중합체로 전달하는 역할을 한다. 따라서, 본 발명에 따라 제조되는 고흡수성 수지는 개선된 초기 흡수 속도를 나타낼 수 있다. 또한, 상기와 같은 섬유는 공정 적용에 용이하고 단가가 저렴할 뿐만 아니라 인체에 무해하므로, 본 발명에 따르면 간단하고 경제적인 방법으로, 인체 친화적이고 흡수능이 우수한 고흡수성 수지를 제조할 수 있다.When fibers are added to the step of compacting the hydrogel polymer, the fibers adsorbed on the surface of the hydrogel polymer particles may be incorporated into the particles by the chopper. Accordingly, at least a portion of the fibers are mixed in a form penetrating the inside of the particles of the base resin, and fibers may be distributed both inside and outside the base resin particles. As described above, the fibers distributed inside and outside of the base resin serve to absorb the surrounding moisture rapidly through the capillary action and transfer it to the polymer. Therefore, the superabsorbent polymer prepared according to the present invention can exhibit an improved initial absorption rate. In addition, such fibers are easy to apply to the process and are not only inexpensive, but also harmless to the human body, and according to the present invention, it is possible to manufacture a superabsorbent polymer that is human-friendly and excellent in absorbency in a simple and economical manner.
상기 플러프 펄프는 셀룰로오스 플러프 펄프로서, 침엽수 크라프트 종이, 광엽수 크라프트펄프 등의 목재 플러프 펄프일 수 있으나 이에 제한되는 것은 아니며, 흡수성 물품에 사용되는 플러프 펄프가 제한 없이 사용될 수 있다.The fluff pulp is a cellulose fluff pulp, but may be wood fluff pulp such as softwood kraft paper, broadleaf kraft pulp, but is not limited thereto, and fluff pulp used for absorbent articles may be used without limitation.
상기 합성 고분자 섬유는 나일론, 폴리프로필렌, 폴리에틸렌, 폴리에스터, 폴리아크릴로니트릴, 폴리염화비닐, 폴리비닐알콜, 폴리아크릴레이트, 및 아세테이트로 이루어지는 군에서 선택되는 1종 이상일 수 있다. 이와 같은 합성 고분자 섬유는 흡습성이 우수하고, 섬유의 너비나 길이를 조절하기 용이하여 고흡수성 수지의 물성 조절이 용이할 수 있다.The synthetic polymer fiber may be at least one selected from the group consisting of nylon, polypropylene, polyethylene, polyester, polyacrylonitrile, polyvinyl chloride, polyvinyl alcohol, polyacrylate, and acetate. Such a synthetic polymer fiber is excellent in hygroscopicity, and it is easy to control the width or length of the fiber, so it is possible to easily control the physical properties of the super absorbent polymer.
상기 섬유는 1 내지 20 mm의 길이를 가지는 것이 바람직하게 사용될 수 있다. 또, 상기 섬유는 너비가 1 내지 100 ㎛인 것이 바람직할 수 있다. 상기 범위를 초과하여 섬유의 길이가 너무 길거나, 너비가 너무 넓으면, 함수겔상 중합체와 섬유를 함께 다지는 과정에서 부하가 발생할 수 있으며, 베이스 수지 입자 내부 및 외부에 섬유가 흡착되기 힘들어 고흡수성 수지에 섬유를 고르게 분포시키기 어려울 수 있다. 또, 섬유의 길이가 너무 짧거나, 너비가 너무 좁으면 고흡수성 수지의 물성 개선 효과가 미미할 수 있으므로, 상기 범위를 만족함이 바람직하다.The fiber may be preferably used having a length of 1 to 20 mm. In addition, the fiber may preferably have a width of 1 to 100 μm. If the length of the fiber exceeds the above range or the width is too wide, a load may occur in the process of compacting the water-containing gel polymer and the fiber, and it is difficult to adsorb the fiber inside and outside the base resin particles, so that the super absorbent polymer is It can be difficult to evenly distribute the fibers. In addition, if the length of the fiber is too short or the width is too narrow, the effect of improving the properties of the super absorbent polymer may be insignificant, so it is preferable to satisfy the above range.
한편, 상술한 길이 및 너비를 만족하는 범위 내에서, 섬유의 길이 및 너비가 증가할수록 비교적 큰 함수겔 중합체 입자에 섬유가 더 많이 흡착되는 효과를 나타낼 수 있다. 이 경우, 이후 진행되는 표면 가교 단계에서 베이스 수지 입자의 입도 편차에 관계 없이 표면 가교액이 보다 고르게 도포될 수 있으므로 표면 가교 효율을 더욱 높일 수 있다.On the other hand, within the range that satisfies the above-described length and width, as the length and width of the fiber increases, it may exhibit the effect of more fibers being adsorbed on the relatively large hydrogel polymer particles. In this case, since the surface crosslinking solution can be more evenly applied regardless of the particle size variation of the base resin particles in the subsequent surface crosslinking step, the surface crosslinking efficiency can be further increased.
즉, 베이스 수지 입자의 크기가 작을수록 액체, 즉 표면 가교액에 대한 흡수 속도가 빠르므로, 베이스 수지의 입도에 따라 가교도에 편차가 발생하고, 결국 고흡수성 수지 입자간 흡수 물성에 편차가 발생할 수 있는데, 상기와 같이 비교적 큰 함수겔 중합체 입자에 섬유가 더 많이 흡착되면 흡착된 섬유로 인해 작은 입자와의 흡수 속도 편차가 줄어들 수 있다. 따라서, 베이스 수지의 입도에 관계 없이 표면 가교액의 도포 정도가 균일해지고, 가교도 편차가 줄어들어, 제조되는 고흡수성 수지의 전반적인 물성 밸런스를 향상시킬 수 있다.In other words, the smaller the size of the base resin particles, the faster the absorption rate for the liquid, that is, the surface crosslinking liquid, and thus a variation in crosslinking degree may occur depending on the particle size of the base resin, and eventually, a variation in absorption properties between the superabsorbent polymer particles may occur. However, if more fibers are adsorbed on the relatively large hydrogel polymer particles as described above, the adsorption rate deviation with the small particles may be reduced due to the adsorbed fibers. Therefore, regardless of the particle size of the base resin, the degree of application of the surface crosslinking solution becomes uniform, and the variation in crosslinking degree decreases, thereby improving the overall physical property balance of the superabsorbent polymer produced.
이와 같은 효과를 확보하기 위해서, 섬유의 길이는 2 mm 이상, 또는 3 mm 이상이면서 15 mm 이하, 또는 10 mm 이하일 수 있다. 일례로, 상기 섬유 개개의 길이가 1 내지 20 mm를 만족하면서, 평균 길이가 3 내지 10 mm 범위를 만족하는 섬유가 바람직하게 사용될 수 있다. 이때 섬유의 평균 길이는 섬유 100 개를 무작위로 선택하여 개별 섬유의 길이를 측정하고, 이의 평균값을 계산함으로써 도출될 수 있다.In order to secure such an effect, the length of the fibers may be 2 mm or more, or 3 mm or more, and 15 mm or less, or 10 mm or less. As an example, while the individual fiber length satisfies 1 to 20 mm, the fiber having an average length of 3 to 10 mm may be preferably used. At this time, the average length of the fibers can be derived by randomly selecting 100 fibers, measuring the length of individual fibers, and calculating the average value thereof.
또, 섬유의 너비는 10 ㎛ 이상, 15 ㎛ 이상, 30 ㎛ 이상, 또는 50 ㎛ 이상이면서,90 ㎛ 이하, 또는 80 ㎛ 이하일 수 있다.In addition, the width of the fiber may be 10 μm or more, 15 μm or more, 30 μm or more, or 50 μm or more, and 90 μm or less, or 80 μm or less.
상기 섬유의 함량은 함수겔상 중합체 100 중량부에 대하여 1 중량부 이상, 3 중량부 이상, 또는 5 중량부 이상이면서, 18 중량부 이하, 15 중량부 이하, 또는 10 중량부 이하 일 수 있다. 만일 섬유가 함수겔상 중합체 100 중량부에 대하여 1 중량부 미만이면 섬유를 포함함에 따른 흡수 속도 향상 효과를 확보할 수 없고, 18 중량부를 초과하면 제조되는 고흡수성 수지의 원심분리 보수능(CRC), 가압 흡수능(AUL) 등의 기본적인 흡수 성능과 흡수 속도가 저하될 수 있고, 함수겔상 중합체를 다지는 단계에서 기계적 부하가 증가하는 문제가 발생할 수 있다.The content of the fiber may be 1 part by weight or more, 3 parts by weight or more, or 5 parts by weight or more, and 18 parts by weight or less, 15 parts by weight or less, or 10 parts by weight or less based on 100 parts by weight of the hydrogel polymer. If the fiber is less than 1 part by weight based on 100 parts by weight of the hydrogel polymer, the effect of improving the absorption rate due to the inclusion of the fiber cannot be secured, and if it exceeds 18 parts by weight, the centrifugal water retention capacity (CRC) of the superabsorbent polymer produced is Basic absorption performance such as pressurized absorption capacity (AUL) and absorption rate may be lowered, and a problem that mechanical load increases in the step of compacting the hydrogel polymer may occur.
이때, 상기 d) 및 e) 단계는 2 내지 5회 반복될 수 있다. 상기 d) 및 e) 단계를 2회 이상 반복함으로써 섬유와 함수겔상 중합체의 혼합도를 더욱 향상시킬 수 있으며, 이에 따라 제조되는 고흡수성 수지의 흡수 속도를 더욱 향상시킬 수 있다.At this time, steps d) and e) may be repeated 2 to 5 times. By repeating the steps d) and e) two or more times, the degree of mixing of the fiber and the hydrogel polymer can be further improved, and thus the absorption rate of the superabsorbent polymer produced can be further improved.
만일, d) 및 e) 단계를 2회 이상 반복하는 경우에는 원활한 혼합을 위하여 각 반복 회차당 동량의 섬유를 투입할 수 있으나, 총 투입되는 섬유의 함량은 상기 범위를 벗어나지 않도록 하는 것이 바람직하다.If the steps d) and e) are repeated two or more times, the same amount of fibers can be added for each repetition for smooth mixing, but it is preferable that the total content of the added fibers is within the above range.
또한, 상기 c) 내지 e) 단계 중 1 이상의 단계에서 물을 더 첨가할 수 있다. 함수겔상 중합체를 다지는 단계에 적정량의 물을 첨가하면 분쇄기의 부하를 낮출 수 있고, 함수겔상 중합체가 보다 고르게 다져질 수 있으며 이에 따라 함수겔상 중합체의 입도가 용이하게 조절될 수 있다. 상기 물은 증류수일 수 있으며, 각 단계에서 첨가되는 물의 양은 특별히 제한되는 것은 아니나, 일례로 함수겔상 중합체 100 중량부에 대하여 1 내지 20 중량부일 수 있다.In addition, water may be further added in at least one of the steps c) to e). Adding an appropriate amount of water to the step of compacting the hydrogel polymer can lower the load of the grinder, the hydrogel polymer can be more evenly compacted, and accordingly the particle size of the hydrogel polymer can be easily adjusted. The water may be distilled water, and the amount of water added in each step is not particularly limited, but may be, for example, 1 to 20 parts by weight based on 100 parts by weight of the hydrogel polymer.
상기 e) 단계가 최종적으로 완료된, 섬유를 포함하는 함수겔상 중합체는, 입도가 1 내지 15 mm 범위인 것이 바람직하다. 상기 입도 범위에서, 건조 단계의 효율이 증대될 수 있다.The e) step is finally completed, the hydrogel polymer containing fibers, it is preferable that the particle size is in the range of 1 to 15 mm. In the particle size range, the efficiency of the drying step may be increased.
다음에,f) 상기 혼합물을 건조한다.Next, f) the mixture is dried.
이때 상기 건조 단계의 건조 온도는 약 150 내지 약 200℃일 수 있다. 건조 온도가 150℃ 미만인 경우, 건조 시간이 지나치게 길어지고 최종 형성되는 고흡수성 수지의 물성이 저하될 우려가 있고, 건조 온도가 200℃를 초과하는 경우, 지나치게 중합체 표면만 건조되어, 추후 이루어지는 분쇄 공정에서 미분이 발생할 수도 있고, 최종 형성되는 고흡수성 수지의 물성이 저하될 우려가 있다. 따라서 바람직하게 상기 건조는 약 150 내지 약 200℃의 온도에서, 더욱 바람직하게는 약 160 내지 약 180℃의 온도에서 진행될 수 있다.At this time, the drying temperature of the drying step may be about 150 to about 200 ℃. When the drying temperature is less than 150°C, the drying time is too long and there is a fear that the physical properties of the superabsorbent resin to be formed are lowered. When the drying temperature exceeds 200°C, only the polymer surface is dried excessively, and a subsequent grinding process is performed. In the fine powder may be generated, there is a fear that the physical properties of the superabsorbent polymer to be formed finally decreases. Therefore, preferably, the drying may be performed at a temperature of about 150 to about 200°C, more preferably at a temperature of about 160 to about 180°C.
한편, 건조 시간의 경우에는 공정 효율 등을 고려하여, 약 20분 내지 약 1 시간 동안 진행될 수 있으나, 이에 한정되지는 않는다.Meanwhile, in the case of the drying time, process efficiency and the like may be considered, but may be performed for about 20 minutes to about 1 hour, but is not limited thereto.
상기 건조 단계의 건조 방법 역시 함수겔상 중합체의 건조 공정으로 통상 사용되는 것이면, 그 구성의 한정이 없이 선택되어 사용될 수 있다. 구체적으로, 열풍 공급, 적외선 조사, 극초단파 조사, 또는 자외선 조사 등의 방법으로 건조 단계를 진행할 수 있다. 이와 같은 건조 단계 진행 후의 중합체의 함수율은 약 0.1 내지 약 10 중량%일 수 있다.The drying method of the drying step may also be selected and used without limitation, as long as it is commonly used as a drying process for the hydrogel polymer. Specifically, the drying step may be performed by a method such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation. The moisture content of the polymer after the drying step may be about 0.1 to about 10% by weight.
다음에,g) 상기 건조 단계를 거쳐 얻어진 건조된 혼합물을 분쇄한다.Next, g) the dried mixture obtained through the drying step is pulverized.
분쇄 단계 후 얻어지는 중합체 분말은 입경이 약 150 내지 약 850 ㎛ 일 수 있다. 이와 같은 입경으로 분쇄하기 위해 사용되는 분쇄기는 구체적으로, 핀 밀(pin mill), 해머 밀(hammer mill), 스크류 밀(screw mill), 롤 밀(roll mill), 디스크 밀(disc mill) 또는 조그 밀(jog mill) 등을 사용할 수 있으나, 상술한 예에 본 발명이 한정되는 것은 아니다.The polymer powder obtained after the grinding step may have a particle size of about 150 to about 850 μm. The pulverizer used for pulverizing to such a particle size is specifically, a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill or a jog. A mill may be used, but the present invention is not limited to the examples described above.
이와 같은 분쇄 단계 이후 최종 제품화되는 고흡수성 수지 분말의 물성을 관리하기 위해, 일반적으로 분쇄 후 얻어지는 중합체 분말을 입경에 따라 분급한다. 바람직하게는 입경이 약 150㎛ 미만인 입자, 약 150 내지 약 850㎛인 입자, 입경이 850㎛를 초과하는 입자로 분급하는 단계를 거칠 수 있다.In order to manage the physical properties of the superabsorbent polymer powder finally produced after such a pulverization step, the polymer powder obtained after pulverization is generally classified according to particle size. Preferably, it may be subjected to a step of classifying particles having a particle diameter of less than about 150 μm, particles having a diameter of about 150 to about 850 μm, and particles having a particle diameter of greater than 850 μm.
한편, 본 발명의 고흡수성 수지의 제조 방법은, h) 상기 g) 단계 이후 얻어진 혼합물에 표면 가교제를 첨가하고, i) 표면 가교 반응을 진행하는 단계를 더 포함할 수 있다.Meanwhile, the method for preparing a super absorbent polymer of the present invention may further include h) adding a surface crosslinking agent to the mixture obtained after step g), and i) progressing a surface crosslinking reaction.
상기 표면 가교 단계는 표면 가교제의 존재 하에 상기 혼합물, 즉, 표면에 섬유를 포함하는 중합체의 표면에 가교 반응을 유도함으로써, 보다 향상된 물성을 갖는 고흡수성 수지를 형성시키는 단계이다. 이러한 표면 가교를 통해 상기 분쇄된 중합체 입자의 표면에는 표면 가교층(표면 개질층)이 형성된다.The surface crosslinking step is a step of forming a superabsorbent polymer having improved physical properties by inducing a crosslinking reaction on the surface of the mixture, that is, a polymer containing fibers on the surface, in the presence of a surface crosslinking agent. Through the surface crosslinking, a surface crosslinking layer (surface modification layer) is formed on the surface of the pulverized polymer particles.
일반적으로, 표면 가교제는 고흡수성 수지 입자의 표면에 도포되므로 표면 가교 반응은 고흡수성 수지 입자의 표면 상에서 일어나며, 이는 입자 내부에는 실질적으로 영향을 미치지 않으면서 입자의 표면 상에서의 가교 결합성은 개선시킨다. 따라서 표면 가교 결합된 고흡수성 수지 입자는 내부에서보다 표면 부근에서 더 높은 가교 결합도를 갖는다.In general, the surface crosslinking agent is applied to the surface of the superabsorbent polymer particles, so that the surface crosslinking reaction occurs on the surface of the superabsorbent polymer particles, which improves the crosslinkability on the surface of the particles without substantially affecting the inside of the particles. Therefore, the surface-crosslinked superabsorbent polymer particles have a higher degree of crosslinking near the surface than from the inside.
상기 표면 가교제로는 기존부터 고흡수성 수지의 제조에 사용되던 표면 가교제를 별다른 제한 없이 모두 사용할 수 있다. 이의 보다 구체적인 예로는, 에틸렌 글리콜, 프로필렌 글리콜, 1,3-프로판디올, 1,4-부탄디올, 1,6-헥산디올, 1,2-헥산디올, 1,3-헥산디올, 2-메틸-1,3-프로판디올, 2,5-헥산디올, 2-메틸-1,3-펜탄디올, 2-메틸-2,4-펜탄디올, 트리프로필렌 글리콜 및 글리세롤로 이루어진 군에서 선택된 1 종 이상의 폴리올; 에틸렌 카보네이트 및 프로필렌 카보네이트로 이루어진 군에서 선택된 1 종 이상의 카보네이트계 화합물; 에틸렌글리콜 디글리시딜에테르 등의 에폭시 화합물; 옥사졸리디논 등의 옥사졸린 화합물; 폴리아민 화합물; 옥사졸린 화합물; 모노-, 디- 또는 폴리옥사졸리디논 화합물; 혹은 환상 우레아 화합물; 등을 들 수 있다.As the surface crosslinking agent, any surface crosslinking agent that has been used in the manufacture of super absorbent polymers can be used without any limitation. More specific examples thereof, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, 2-methyl- One or more polyols selected from the group consisting of 1,3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, tripropylene glycol and glycerol ; At least one carbonate-based compound selected from the group consisting of ethylene carbonate and propylene carbonate; Epoxy compounds such as ethylene glycol diglycidyl ether; Oxazoline compounds such as oxazolidinone; Polyamine compounds; Oxazoline compounds; Mono-, di- or polyoxazolidinone compounds; Or cyclic urea compounds; And the like.
이러한 표면 가교제는 g) 단계에서 얻어진 혼합물 100 중량부에 대하여 약 0.01 내지 5 중량부의 함량으로 사용될 수 있다. 표면 가교제의 함량 범위를 상술한 범위로 조절하여 우수한 흡수 제반 물성을 나타내는 고흡수성 수지를 제공할 수 있다.The surface crosslinking agent may be used in an amount of about 0.01 to 5 parts by weight based on 100 parts by weight of the mixture obtained in step g). By adjusting the content range of the surface crosslinking agent to the above-described range, it is possible to provide a super absorbent polymer exhibiting excellent water absorption properties.
상기 표면 가교제는 상기 g) 단계에서 얻어진 혼합물과 건식으로 혼합되거나, 표면 가교 용액의 형태로 투입될 수 있다. 상기 표면 가교 용액의 용매로는 물, 메탄올, 에탄올, 프로필렌 글리콜 및 이들의 조합이 사용 가능하나, 이에 제한되는 것은 아니다.The surface crosslinking agent may be dry mixed with the mixture obtained in step g) or may be added in the form of a surface crosslinking solution. Water, methanol, ethanol, propylene glycol, and combinations thereof may be used as the solvent of the surface crosslinking solution, but are not limited thereto.
한편, 상기 표면 가교 단계에서는 상술한 표면 가교제 이외에, 필요에 따라 다가 금속염, 무기 충전제, 증점제 등을 더 포함할 수 있다. 이러한 첨가제들은 상기 g) 단계에서 얻어진 혼합물과 건식으로 혼합되거나, 표면 가교 용액에 첨가된 형태로 혼합될 수 있다.Meanwhile, in the surface crosslinking step, in addition to the surface crosslinking agent described above, a polyvalent metal salt, an inorganic filler, a thickener, and the like may be further included as necessary. These additives may be dry mixed with the mixture obtained in step g), or in the form added to the surface crosslinking solution.
상기 다가 금속염으로는 예를 들어, 알루미늄 염, 보다 구체적으로 알루미늄의 황산염, 칼륨염, 암모늄염, 나트륨염 및 염산염으로 이루어진 군에서 선택된 1종 이상을 더 포함할 수 있다.The polyvalent metal salt may further include, for example, at least one selected from the group consisting of aluminum salts, more specifically aluminum sulfates, potassium salts, ammonium salts, sodium salts, and hydrochloride salts.
이러한 다가 금속염은 추가로 사용함에 따라, 일 구현예의 방법으로 제조된 고흡수성 수지의 통액성 등을 더욱 향상시킬 수 있다. 이러한 다가 금속염은 상기 표면 가교제와 함께 표면 가교 용액에 첨가될 수 있으며, 상기 베이스 수지 100 중량부에 대하여 0.01 내지 4 중량부의 함량으로 사용될 수 있다.As the polyvalent metal salt is further used, the liquid permeability of the superabsorbent polymer produced by the method of one embodiment can be further improved. The polyvalent metal salt may be added to the surface crosslinking solution together with the surface crosslinking agent, and may be used in an amount of 0.01 to 4 parts by weight based on 100 parts by weight of the base resin.
상기 무기 충전제로는 실리카, 알루미늄 옥사이드, 또는 실리케이트를 포함할 수 있다. 상기 무기 충전제는 상기 베이스 수지 분말의 100 중량부를 기준으로, 0.01 내지 0.5 중량부로 포함될 수 있다. 이러한 무기 충전제는 윤활제로 작용하여 고흡수성 수지 표면에 표면 가교 용액의 도포 효율을 향상시킬 수 있고, 제조된 고흡수성 수지의 통액성 등을 더욱 향상시킬 수 있다.The inorganic filler may include silica, aluminum oxide, or silicate. The inorganic filler may be included in an amount of 0.01 to 0.5 parts by weight based on 100 parts by weight of the base resin powder. Such an inorganic filler can act as a lubricant to improve the application efficiency of the surface crosslinking solution on the surface of the super absorbent polymer, and further improve the liquid permeability of the prepared super absorbent polymer.
상기 표면 가교 단계에서 증점제를 추가로 포함할 수 있다. 이렇게 증점제 존재 하에 베이스 수지 분말의 표면을 추가로 가교하면 분쇄 후에도 물성 저하를 최소화할 수 있다. 구체적으로, 상기 증점제로는 다당류 및 히드록시 함유 고분자 중 선택된 1 종 이상이 사용될 수 있다. 상기 다당류로는 검 계열 증점제와 셀룰로오스 계열 증점제 등이 사용될 수 있다. 상기 검 계열 증점제의 구체적인 예로는, 잔탄 검(xanthan gum), 아라빅 검(arabic gum), 카라야 검(karaya gum), 트래거캔스 검(tragacanth gum), 가티 검(ghatti gum), 구아 검(guar gum), 로커스트 빈 검(locust bean gum) 및 사일리움 씨드 검(psyllium seed gum) 등을 들 수 있고, 상기 셀룰로오스 계열 증점제의 구체적인 예로는, 히드록시프로필메틸셀룰로오스, 카르복시메틸셀룰로오스, 메틸셀룰로오스, 히드록시메틸셀룰로오스, 히드록시에틸셀룰로오스, 히드록시프로필셀룰로오스, 히드록시에틸메틸셀룰로오스, 히드록시메틸프로필셀룰로오스, 히드록시에틸히드록시프로필셀룰로오스, 에틸히드록시에틸셀룰로오스 및 메틸히드록시프로필셀룰로오스 등을 들 수 있다. 한편, 상기 히드록시 함유 고분자의 구체적인 예로는 폴리에틸렌글리콜 및 폴리비닐알코올 등을 들 수 있다.In the surface crosslinking step, a thickener may be further included. When the surface of the base resin powder is further crosslinked in the presence of a thickener in this way, deterioration in physical properties can be minimized even after grinding. Specifically, one or more selected from polysaccharides and hydroxy-containing polymers may be used as the thickener. As the polysaccharide, a gum-based thickener and a cellulose-based thickener may be used. Specific examples of the gum-based thickener include xanthan gum, arabic gum, karaya gum, tragacanth gum, ghatti gum, guar gum (guar gum), locust bean gum (locust bean gum) and silylium seed gum, and the like, and specific examples of the cellulose-based thickener include hydroxypropyl methyl cellulose, carboxymethyl cellulose, and methyl cellulose , Hydroxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxyethylmethylcellulose, hydroxymethylpropylcellulose, hydroxyethylhydroxypropylcellulose, ethylhydroxyethylcellulose and methylhydroxypropylcellulose You can. Meanwhile, specific examples of the hydroxy-containing polymer include polyethylene glycol and polyvinyl alcohol.
상기 표면 가교 반응은, 분쇄된 함수겔상 중합체, 표면 가교제 및 섬유의 혼합물에 열을 가하여 승온함으로써 수행될 수 있다.The surface crosslinking reaction may be performed by heating the mixture of the pulverized hydrogel polymer, the surface crosslinking agent, and the fibers to raise the temperature.
상기 표면 가교 단계는 185 ℃ 이상, 바람직하게는 185 내지 약 230 ℃의 온도에서 약 10 내지 약 90 분, 바람직하게는 약 20 내지 약 70 분 동안 가열시킴으로써 수행할 수 있다. 가교 반응 온도가 185 ℃ 미만이거나 반응 시간이 너무 짧을 경우 표면 가교제가 함수겔상 중합체와 충분하게 반응하지 못하는 문제가 있을 수 있고, 230℃를 초과하거나 반응 시간이 너무 길 경우 함수겔상 중합체가 분해되어 물성 저하 문제가 발생할 수 있다.The surface crosslinking step may be performed by heating at a temperature of 185°C or higher, preferably 185 to about 230°C, for about 10 to about 90 minutes, preferably about 20 to about 70 minutes. If the crosslinking reaction temperature is less than 185 °C or the reaction time is too short, there may be a problem that the surface crosslinking agent does not sufficiently react with the hydrogel polymer, and if it exceeds 230 °C or the reaction time is too long, the hydrogel polymer decomposes and physical properties Degradation problems may occur.
표면 가교 반응을 위한 승온 수단은 특별히 한정되지 않는다. 열매체를 공급하거나, 열원을 직접 공급하여 가열할 수 있다. 이때, 사용 가능한 열매체의 종류로는 스팀, 열풍, 뜨거운 기름과 같은 승온한 유체 등을 사용할 수 있으나, 본 발명이 이에 한정되는 것은 아니며, 또한 공급되는 열매체의 온도는 열매체의 수단, 승온 속도 및 승온 목표 온도를 고려하여 적절히 선택할 수 있다. 한편, 직접 공급되는 열원으로는 전기를 통한 가열, 가스를 통한 가열 방법을 들 수 있으나, 상술한 예에 본 발명이 한정되는 것은 아니다.The heating means for the surface crosslinking reaction is not particularly limited. The heating medium may be supplied or a heat source may be directly supplied to heat. At this time, as the kind of heat medium that can be used, a heated fluid such as steam, hot air, and hot oil may be used, but the present invention is not limited to this, and the temperature of the heat medium supplied is the means of the heat medium, the rate of temperature increase, and the temperature increase. It can be appropriately selected in consideration of the target temperature. On the other hand, the heat source directly supplied may include a heating method through electricity or a gas, but the present invention is not limited to the above-described example.
상기와 같은 표면 가교 반응 단계에 의해, 상기 중합체의 표면에는 표면 개질층이 형성될 수 있다.By the surface crosslinking reaction step as described above, a surface modification layer may be formed on the surface of the polymer.
상기 본 발명의 제조방법에 따라 제조된 고흡수성 수지는 플러프 펄프 및 합성 고분자 섬유 중 1종 이상의 섬유를 포함함에 따라 향상된 흡수 속도를 나타낸다.The superabsorbent polymer prepared according to the manufacturing method of the present invention exhibits an improved absorption rate as it includes at least one fiber among fluff pulp and synthetic polymer fibers.
이에, 본 발명의 일 구현예에 따르면, 수용성 에틸렌계 불포화 단량체가 내부 가교제의 존재 하에 가교 중합된 가교 중합체, 및 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 포함하는 베이스 수지 입자; 및 상기 베이스 수지 입자의 표면에 형성되어 있고, 상기 가교 중합체가 표면 가교제를 매개로 추가 가교된 표면 가교층을 포함하는 고흡수성 수지로서, 상기 섬유의 적어도 일부는 상기 베이스 수지 입자의 내부를 관통하여 혼입되어 있는 것인, 고흡수성 수지가 제공된다.Thus, according to an embodiment of the present invention, the water-soluble ethylenically unsaturated monomer is a crosslinked polymer crosslinked in the presence of an internal crosslinking agent, and base resin particles comprising at least one fiber of fluff pulp and synthetic polymer fibers; And it is formed on the surface of the base resin particles, the cross-linking polymer is a super absorbent polymer comprising a surface cross-linking layer further cross-linked through a surface cross-linking agent, at least a portion of the fiber penetrates the interior of the base resin particles A superabsorbent polymer that is incorporated is provided.
본 발명의 고흡수성 수지는 베이스 수지 제조 시 함수겔상 중합체를 다지는 과정에서 흡습성이 우수한 섬유를 포함하여, 입자 상의 베이스 수지 내부 및 외부에 섬유가 고르게 분포될 수 있다. 이에 따라, 본 발명의 고흡수성 수지는 보수능, 가압 흡수능과 같은 기본적인 흡수 성능이 우수하면서도, 향상된 흡수 속도 및 통액성을 나타낼 수 있다.The superabsorbent polymer of the present invention includes fibers having excellent hygroscopicity in the process of compacting a hydrogel polymer during base resin production, and fibers can be evenly distributed inside and outside the base resin on the particles. Accordingly, the superabsorbent polymer of the present invention has excellent basic absorption performance such as water retention capacity and pressure absorption capacity, and can exhibit improved absorption speed and liquid permeability.
구체적으로, 상기 고흡수성 수지는, EDANA 법 WSP 241.3에 따라 측정한 보수능(CRC)이 약 25 g/g 이상, 28 g/g 이상, 또는 약 30 g/g 이상이면서, 약 45 g/g 이하, 40 g/g 이하, 또는 약 35 g/g 이하의 범위를 가질 수 있다.Specifically, the superabsorbent polymer has a water retention capacity (CRC) measured according to EDANA method WSP 241.3 of about 25 g/g or more, 28 g/g or more, or about 30 g/g or more, and about 45 g/g. Or less, 40 g/g or less, or about 35 g/g or less.
또, 상기 고흡수성 수지는 EDANA 법 WSP 242.3에 따라 측정한 0.3 psi의 가압 흡수능(AUL)이 25 g/g 이상, 또는 27 g/g 이상이면서, 40 g/g 이하, 또는 30 g/g 이하일 수 있다.In addition, the superabsorbent polymer has a pressure absorption capacity (AUL) of 0.3 psi measured according to EDANA method WSP 242.3 of 25 g/g or more, or 27 g/g or more, and 40 g/g or less, or 30 g/g or less. Can be.
또, 상기 고흡수성 수지는 23 ℃ 내지 24 ℃의 50 mL의 생리 식염수에 2 g의 고흡수성 수지를 넣고, 마그네틱 바(직경 8 mm, 길이 31.8 mm)를 600 rpm으로 교반하여 와류(vortex)가 사라질 때까지의 시간(초)으로 측정되는 흡수 속도(vortex time)가 50초 이하, 또는 45초 이하일 수 있다. 상기 흡수 속도는 낮을수록 우수한 것으로서 그 하한값은 제한되지 않으나, 일례로 10초 이상, 또는 20초 이상일 수 있다.In addition, the superabsorbent polymer is added to 2 g of superabsorbent polymer in 50 mL of physiological saline at 23°C to 24°C, and a magnetic bar (8 mm in diameter and 31.8 mm in length) is stirred at 600 rpm to obtain vortex. The vortex time, measured in seconds until disappearance, may be 50 seconds or less, or 45 seconds or less. The lower the absorption rate, the better, and the lower limit is not limited, but may be, for example, 10 seconds or more, or 20 seconds or more.
한편, 본 발명의 일 구현예에 따르면, 고흡수성 수지 입자; 및 플러프 펄프 및 합성 고분자 섬유 중 1종 이상의 섬유를 포함하며, 상기 섬유의 적어도 일부가 상기 고흡수성 수지 입자의 내부를 관통하며 혼입되어 있는 고흡수성 수지 조성물이 제공된다.On the other hand, according to an embodiment of the present invention, superabsorbent polymer particles; And it includes a fluff pulp and one or more fibers of synthetic polymer fibers, at least a portion of the fiber is provided with a superabsorbent polymer composition that penetrates through the interior of the superabsorbent polymer particles.
즉, 상기 고흡수성 수지 조성물에서, 섬유 일부는 고흡수성 수지 입자 외부에 존재하고, 일부는 고흡수성 수지 입자 내에 박혀있는 상태로 존재한다. 이에 따라 본 발명의 고흡수성 수지 조성물은 단순히 고흡수성 수지와 흡습성 섬유를 혼합한 조성물과 비교하여 향상된 흡수 속도를 나타낼 수 있다.That is, in the superabsorbent polymer composition, a part of the fibers are present outside the superabsorbent polymer particles, and some are present in a state embedded in the superabsorbent polymer particles. Accordingly, the superabsorbent polymer composition of the present invention can exhibit an improved absorption rate compared to a composition in which a superabsorbent polymer and hygroscopic fiber are simply mixed.
이하 본 발명을 실시예에 기초하여 더욱 상세하게 설명한다. 단, 하기의 실시예는 본 발명을 예시하는 것일 뿐, 본 발명의 내용이 하기의 실시예에 의하여 한정되는 것은 아니다. 또한, 이하의 실시예, 비교예에서 함유량을 나타내는 "%" 및 "부"는 특별히 언급하지 않는 한 질량 기준이다.Hereinafter, the present invention will be described in more detail based on examples. However, the following examples are only illustrative of the present invention, and the contents of the present invention are not limited by the following examples. In addition, "%" and "part" showing content in the following Examples and Comparative Examples are based on mass unless otherwise specified.
<실시예><Example>
고흡수성 수지의 제조Preparation of super absorbent polymer
실시예 1 내지 10Examples 1 to 10
아크릴산 100 g, 가교제로 폴리에틸렌글리콜디아크릴레이트(PEGDA, Mw=523) 3.0 g, 광개시제로 Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide 0.008 g, 열개시제로 소디움 퍼설페이트(sodium persulfate; SPS) 0.08 g, 31.5 % 가성소다(NaOH) 128 g, 물 63.5 g을 혼합하여 모노머 수용액 조성물을 제조하였다.100 g of acrylic acid, polyethylene glycol diacrylate (PEGDA, Mw=523) 3.0 g as a crosslinking agent, Phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide 0.008 g as a photoinitiator, sodium persulfate (SPS) as a thermal initiator A monomer aqueous solution composition was prepared by mixing 0.08 g, 31.5% caustic soda (NaOH) 128 g, and water 63.5 g.
상기 모노머 수용액 조성물에 대해 광중합 반응을 진행하여 중합된 시트를 얻었다. 중합된 시트를 꺼내어 3 cm X 3 cm의 크기로 자른 후, 미트 쵸퍼(meat chopper)를 이용하여 다지기 공정(chopping)을 실시하였다. 구체적으로, 상기 중합된 시트를 자른 후 미트 쵸퍼(홀 크기 16 mm, 속도 60 Hz)로 다진 다음, 함수겔상 중합체 100 중량부에 대하여 5 중량부의 증류수를 분무하고, 하기 표 1의 각 섬유를 표 1에 기재된 함량(함수겔상 중합체 100 중량부 대비 중량부로 표기)대로 투입하고, 다시 미트 쵸퍼(홀 크기 16 mm, 속도 60 Hz)로 다졌다. 그 후 보다 균일한 혼합을 위해 다져진 함수겔상 중합체에 5 중량부의 증류수를 분무한 후 미트 쵸퍼(홀 크기 16 mm, 속도 60 Hz)로 다지는 과정을 거쳐 가루(crumb)를 제조하였다. A photopolymerization reaction was performed on the monomer aqueous solution composition to obtain a polymerized sheet. The polymerized sheet was taken out and cut to a size of 3 cm X 3 cm, and then chopping was performed using a meat chopper. Specifically, after cutting the polymerized sheet, chopped with a meat chopper (hole size 16 mm, speed 60 Hz), and then spraying 5 parts by weight of distilled water with respect to 100 parts by weight of hydrogel polymer, and each fiber in Table 1 below It was added according to the content described in 1 (expressed as parts by weight compared to 100 parts by weight of the gel-like polymer), and again minced to a meat chopper (hole size 16 mm, speed 60 Hz). Then, for more uniform mixing, 5 parts by weight of distilled water was sprayed onto the compacted hydrogel polymer, followed by compaction with a meat chopper (hole size 16 mm, speed 60 Hz) to prepare a crumb.
그런 다음, 상기 가루(crumb)를 상하로 풍량 전이가 가능한 오븐에서 건조하였다. 185 ℃의 핫 에어(hot air)를 15분은 하방에서 상방으로, 15분은 상방에서 하방으로 흐르게 하여 균일하게 건조하였으며, 건조 후 건조체의 함수량은 2 % 이하가 되도록 하였다. 건조 후, 분쇄기로 분쇄한 다음, Amplitude 1.5 mm로 10분 분급(분급 mesh 조합: #20 / #30 / #50 / #100)하였으며 각 분급분(10 % / 65 % / 22 % / 3 %)을 수집하여 입경 약 150 ㎛ 내지 850 ㎛인 베이스 수지 분말을 얻었다.Then, the crumb was dried in an oven capable of transferring air volume up and down. The hot air at 185° C. was uniformly dried by flowing from bottom to top for 15 minutes and from top to bottom for 15 minutes, and after drying, the water content of the dried body was set to 2% or less. After drying, it was crushed with a grinder, and then divided into 10 minutes with Amplitude 1.5 mm (classification mesh combination: #20 / #30 / #50 / #100) and each classification (10% / 65% / 22% / 3 %) Was collected to obtain a base resin powder having a particle diameter of about 150 μm to 850 μm.
이후, 상기 제조한 베이스 수지 100 중량부에, 표면 가교액(물 6.2 중량부, 메탄올 6.2 중량부, 에틸렌글리콜 디글리시딜 에테르 0.03 중량부, 실리카 Aerosil200 0.01 중량부)을 고르게 혼합한 후, 140℃에서 30분 동안 표면 가교 반응을 진행하였다. 상기 표면 처리 완료 후, 시브(sieve)를 이용하여 평균입경 850 ㎛ 이하인 고흡수성 수지를 얻었다.Then, 100 parts by weight of the prepared base resin, surface crosslinking solution (6.2 parts by weight of water, 6.2 parts by weight of methanol, 0.03 parts by weight of ethylene glycol diglycidyl ether, 0.01 parts by weight of silica Aerosil200), and evenly mixed, 140 The surface crosslinking reaction was performed at 30°C for 30 minutes. After the surface treatment was completed, a super absorbent polymer having an average particle diameter of 850 μm or less was obtained using a sieve.
비교예 1Comparative Example 1
함수겔상 중합체를 다지는 과정에서 섬유를 첨가하지 않은 것을 제외하고는 실시예 1과 동일한 방법으로 고흡수성 수지를 제조하였다.A superabsorbent polymer was prepared in the same manner as in Example 1, except that fibers were not added in the process of compacting the hydrogel polymer.
비교예 2Comparative Example 2
비교예 1의 고흡수성 수지 100 중량부에, 실시예 1에서 사용된 플러프 펄프 5 중량부를 첨가하고 혼합하여, 고흡수성 수지와 플러프 펄프가 단순 혼합된 고흡수성 수지 복합체를 제조하였다.To 100 parts by weight of the superabsorbent polymer of Comparative Example 1, 5 parts by weight of fluff pulp used in Example 1 was added and mixed to prepare a superabsorbent polymer composite in which a superabsorbent polymer and fluff pulp were simply mixed.
<실험예><Experimental Example>
상기 각 실시예 및 비교예의 고흡수성 수지에 대하여 하기 방법으로 물성을 측정하였고, 그 결과를 표 1에 나타내었다.The physical properties of the superabsorbent polymers of each of the Examples and Comparative Examples were measured by the following method, and the results are shown in Table 1.
(1) 원심분리 보수능 (CRC, Centrifugal Retention Capacity)(1) Centrifugal Retention Capacity (CRC)
각 수지의 무하중하 흡수 배율에 의한 보수능을 EDANA WSP 241.3에 따라 측정하였다.The water retention capacity of each resin by the load-free absorption magnification was measured according to EDANA WSP 241.3.
구체적으로, 실시예 및 비교예를 통해 각각 얻은 수지에서, #40-50의 체로 분급한 수지를 얻었다. 이러한 수지 W0(g) (약 0.2g)을 부직포제의 봉투에 균일하게 넣고 밀봉(seal)한 후, 상온에서 생리식염수(0.9 중량%)에 침수시켰다. 30분 경과 후, 원심 분리기를 이용하여 250G의 조건 하에서 상기 봉투로부터 3분간 물기를 빼고, 봉투의 질량 W2(g)을 측정하였다. 또, 수지를 이용하지 않고 동일한 조작을 한 후에 그때의 질량 W1(g)을 측정하였다. 얻어진 각 질량을 이용하여 다음과 같은 식에 따라 CRC(g/g)를 산출하였다.Specifically, from the resins obtained through the examples and comparative examples, resins classified by a sieve of #40-50 were obtained. After the resin W0(g) (about 0.2g) was uniformly put in a nonwoven fabric bag and sealed, it was immersed in physiological saline (0.9% by weight) at room temperature. After 30 minutes, the bag was drained for 3 minutes under the condition of 250G using a centrifuge, and the mass W2 (g) of the envelope was measured. Moreover, the mass W1 (g) at that time was measured after performing the same operation without using a resin. CRC (g/g) was calculated according to the following equation using each obtained mass.
[수학식 1][Equation 1]
Figure PCTKR2019015056-appb-I000001
Figure PCTKR2019015056-appb-I000001
(2) 가압 흡수능 (AUL, Absorbency under Load)(2) Absorbency under Load (AUL)
각 수지의 0.3 psi의 가압 흡수능을, EDANA법 WSP 242.3에 따라 측정하였다. 가압 흡수능 측정시에는, 상기 CRC 측정시의 수지 분급분을 사용하였다.The pressure absorption capacity of 0.3 psi of each resin was measured according to EDANA method WSP 242.3. In the measurement of the pressure absorption capacity, the resin classifier for the CRC measurement was used.
구체적으로, 내경 25 mm의 플라스틱의 원통 바닥에 스테인레스제 400 mesh 철망을 장착시켰다. 상온 및 습도 50 %의 조건 하에서 철망 상에 흡수성 수지 W3(g) (0.16 g)을 균일하게 살포하고, 그 위에 0.3 psi의 하중을 균일하게 더 부여할 수 있는 피스톤은 외경 25 mm 보다 약간 작고 원통의 내벽과 틈이 없고 상하 움직임이 방해 받지 않게 하였다. 이때 상기 장치의 중량 W4(g)을 측정하였다.Specifically, a 400 mesh wire mesh made of stainless steel was mounted on a cylindrical bottom of a plastic having an inner diameter of 25 mm. A piston capable of uniformly spreading the absorbent resin W3(g) (0.16 g) on a wire mesh under conditions of normal temperature and humidity of 50%, and giving a load of 0.3 psi evenly thereon, the piston is slightly smaller than the outer diameter of 25 mm and a cylinder. There was no gap with the inner wall of the and the vertical movement was not disturbed. At this time, the weight W4(g) of the device was measured.
직경 150 mm의 페트로 접시의 내측에 직경 90mm 및 두께 5mm의 유리 필터를 두고, 0.9 중량% 염화나트륨으로 구성된 생리식염수를 유리 필터의 윗면과 동일 레벨이 되도록 하였다. 그 위에 직경 90mm의 여과지 1장을 실었다. 여과지 위에 상기 측정 장치를 싣고, 액을 하중 하에서 1시간 동안 흡수시켰다. 1시간 후 측정 장치를 들어올리고, 그 중량 W5(g)을 측정하였다.A glass filter having a diameter of 90 mm and a thickness of 5 mm was placed inside the petri dish of 150 mm in diameter, and the physiological saline composed of 0.9 wt% sodium chloride was brought to the same level as the top surface of the glass filter. A sheet of filter paper having a diameter of 90 mm was placed thereon. The measuring device was mounted on a filter paper, and the liquid was absorbed for 1 hour under a load. After 1 hour, the measuring device was lifted, and the weight W5 (g) was measured.
얻어진 각 질량을 이용하여 다음 식에 따라 가압 흡수능(g/g)을 산출하였다.Using each mass obtained, pressure absorption capacity (g/g) was calculated according to the following equation.
[수학식 2][Equation 2]
Figure PCTKR2019015056-appb-I000002
Figure PCTKR2019015056-appb-I000002
(3) 흡수 속도(vortex)(3) Absorption rate (vortex)
각 수지의 흡수 속도는 국제특허 공개번호 제1987-003208호에 기재된 방법에 준하여 초 단위로 측정되었다.The absorption rate of each resin was measured in seconds according to the method described in International Patent Publication No. 1987-003208.
구체적으로, 흡수 속도(혹은 vortex time)는 23 ℃ 내지 24 ℃의 50 mL의 생리 식염수에 2 g의 고흡수성 수지를 넣고, 마그네틱 바(직경 8 mm, 길이 31.8 mm)를 600 rpm으로 교반하여 와류(vortex)가 사라질 때까지의 시간을 초 단위로 측정하여 산출되었다.Specifically, the absorption rate (or vortex time) is 2 g of superabsorbent resin in 50 mL of physiological saline at 23°C to 24°C, and the magnetic bar (8 mm in diameter and 31.8 mm in length) is stirred at 600 rpm to vortex. It was calculated by measuring the time until (vortex) disappears in seconds.
Figure PCTKR2019015056-appb-T000001
Figure PCTKR2019015056-appb-T000001
*섬유의 평균 길이는 섬유 100개를 무작위로 선택하여 도출한 길이의 평균 값임.*The average length of the fiber is the average value of the length derived by randomly selecting 100 fibers.
상기 표 1을 참조하면, 본 발명에 따라 제조된 고흡수성 수지는 CRC, AUL 등 기본적인 물성이 우수하면서도, 섬유를 포함하지 않는 비교예 1 및 기존과 같이 기 제조된 고흡수성 수지에 펄프 섬유를 단순 혼합한 비교예 2와 비교하여 현저히 개선된 흡수 속도를 나타내는 것을 확인할 수 있다.Referring to Table 1, the superabsorbent polymer prepared according to the present invention is superior in basic physical properties such as CRC and AUL, but the pulp fiber is simple in Comparative Example 1 that does not contain fibers and the superabsorbent resin previously prepared as described above. It can be seen that it shows a significantly improved absorption rate compared to the mixed comparative example 2.

Claims (16)

  1. a) 수용성 에틸렌계 불포화 단량체, 내부 가교제, 및 중합개시제를 혼합하여 모노머 조성물을 제조하는 단계;a) preparing a monomer composition by mixing a water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator;
    b) 상기 모노머 조성물을 중합하여 함수겔상 중합체를 제조하는 단계;b) polymerizing the monomer composition to prepare a hydrogel polymer;
    c) 상기 함수겔상 중합체를 다지는 단계;c) compacting the hydrogel polymer;
    d) 상기 다져진 함수겔상 중합체에 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 첨가하고 혼합하여 혼합물을 제조하는 단계;d) adding and mixing one or more kinds of fluff pulp and synthetic polymer fibers to the compacted hydrogel polymer to prepare a mixture;
    e) 상기 혼합물을 다지는 단계;e) compacting the mixture;
    f) 상기 혼합물을 건조하는 단계; 및f) drying the mixture; And
    g) 상기 혼합물을 분쇄하는 단계를 포함하는 고흡수성 수지의 제조방법.g) A method for producing a super absorbent polymer comprising crushing the mixture.
  2. 제1항에 있어서,According to claim 1,
    상기 섬유는 함수겔상 중합체 100 중량부에 대하여 1 내지 18 중량부로 포함되는 고흡수성 수지의 제조방법.The fiber is a method for producing a super absorbent polymer contained in 1 to 18 parts by weight based on 100 parts by weight of the hydrogel polymer.
  3. 제1항에 있어서,According to claim 1,
    상기 섬유의 길이는 1 내지 20 mm 인 고흡수성 수지의 제조방법.Method of manufacturing a super absorbent polymer having a length of 1 to 20 mm.
  4. 제1항에 있어서,According to claim 1,
    상기 섬유의 너비는 1 내지 100 ㎛ 인 고흡수성 수지의 제조방법.Method of manufacturing a super absorbent polymer having a width of 1 to 100 μm.
  5. 제1항에 있어서,According to claim 1,
    상기 c) 내지 e) 단계 중 1 이상의 단계에서 물을 더 첨가하는, 고흡수성 수지의 제조방법.Method of producing a super absorbent polymer, further adding water in at least one of the steps c) to e).
  6. 제5항에 있어서,The method of claim 5,
    상기 물은 함수겔상 중합체 100 중량부에 대하여 1 내지 20 중량부로 첨가되는, 고흡수성 수지의 제조 방법.The water is added in 1 to 20 parts by weight based on 100 parts by weight of the hydrogel polymer, a method for producing a super absorbent polymer.
  7. 제1항에 있어서,According to claim 1,
    상기 모노머 조성물은 발포제를 더 포함하는, 고흡수성 수지의 제조 방법.The monomer composition further comprises a blowing agent, a method for producing a super absorbent polymer.
  8. 제7항에 있어서,The method of claim 7,
    상기 모노머 조성물은 알킬 설페이트 염 (alkyl sulfate salt), 알킬 설포네이트 염 (alkyl sulfonate salt), 알킬 포스페이트 염 (alkyl phosphate salt), 알킬 카보네이트 염 (alkyl carbonate salt), 폴리에틸렌 글리콜 알킬 에스테르 (polyethylene glycol alkyl ester), 폴리프로필렌 글리콜 알킬 에스테르 (polypropylene glycol alkyl ester), 글루코사이드 알킬 에스테르 (glucoside alkyl ester), 글리세를 알킬 에스테르 (glycerol alkyl ester), 및 폴리에틸렌 글리콜과 폴리프로필렌 글리콜의 블록-공중합체 (block-copolymers of polyethylene glycol and polypropylene glycol)로 이루어지는 군에서 선택되는 1종 이상의 발포 안정제를 더 포함하는, 고흡수성 수지의 제조 방법.The monomer composition is an alkyl sulfate salt, alkyl sulfonate salt, alkyl phosphate salt, alkyl carbonate salt, polyethylene glycol alkyl ester ), polypropylene glycol alkyl esters, glucoside alkyl esters, glycerol alkyl esters, and block-copolymers of polyethylene glycol and polypropylene glycol. Polyethylene glycol and polypropylene glycol) further comprises at least one foam stabilizer selected from the group consisting of, super absorbent polymer production method.
  9. 제1항에 있어서, 상기 g) 단계 이후,According to claim 1, After step g),
    h) 상기 g) 단계에서 얻어진 혼합물에 표면 가교제를 첨가하는 단계; 및h) adding a surface crosslinking agent to the mixture obtained in step g); And
    i) 표면 가교 반응을 진행하는 단계를 더 포함하는, 고흡수성 수지의 제조 방법.i) A method for producing a super absorbent polymer, further comprising the step of advancing a surface crosslinking reaction.
  10. 제9항에 있어서,The method of claim 9,
    상기 표면 가교제는 다가 알콜 화합물; 에폭시 화합물; 폴리아민 화합물; 할로에폭시 화합물; 할로에폭시 화합물의 축합 산물; 옥사졸린 화합물; 모노-, 디- 또는 폴리옥사졸리디논 화합물; 환상 우레아 화합물; 다가금속염; 및 알킬렌 카보네이트 화합물로 이루어진 군으로 이루어진 군에서 선택되는 1종 이상인, 고흡수성 수지의 제조방법.The surface crosslinking agent is a polyhydric alcohol compound; Epoxy compounds; Polyamine compounds; Halo epoxy compounds; Condensation products of haloepoxy compounds; Oxazoline compounds; Mono-, di- or polyoxazolidinone compounds; Cyclic urea compounds; Polyvalent metal salts; And one or more types selected from the group consisting of alkylene carbonate compounds.
  11. 제9항에 있어서,The method of claim 9,
    상기 표면 가교제는 상기 혼합물 100 중량부에 대하여 0.001 내지 5 중량부로 첨가되는, 고흡수성 수지의 제조방법.The surface crosslinking agent is added in an amount of 0.001 to 5 parts by weight based on 100 parts by weight of the mixture, a method for producing a super absorbent polymer.
  12. 제1항 내지 제11항 중 어느 한 항의 제조방법에 의하여 제조되는 고흡수성 수지.A super absorbent polymer produced by the method of any one of claims 1 to 11.
  13. 수용성 에틸렌계 불포화 단량체가 내부 가교제의 존재 하에 가교 중합된 가교 중합체, 및 플러프 펄프 및 합성 고분자 섬유 중 1 종 이상의 섬유를 포함하는 베이스 수지 입자; 및Base resin particles comprising a crosslinked polymer in which a water-soluble ethylenically unsaturated monomer is crosslinked and polymerized in the presence of an internal crosslinking agent, and one or more fibers of fluff pulp and synthetic polymer fibers; And
    상기 베이스 수지 입자의 표면에 형성되어 있고, 상기 가교 중합체가 표면 가교제를 매개로 추가 가교된 표면 가교층을 포함하는 고흡수성 수지로서,It is formed on the surface of the base resin particles, the crosslinked polymer is a super absorbent polymer comprising a surface crosslinking layer further crosslinked via a surface crosslinking agent,
    상기 섬유의 적어도 일부는 상기 베이스 수지 입자의 내부를 관통하여 혼입되어 있는 것인, 고흡수성 수지.At least a portion of the fibers are mixed through the interior of the base resin particles, super absorbent polymer.
  14. 제13항에 있어서,The method of claim 13,
    EDANA 법 WSP 241.3에 따라 측정한 원심분리 보수능(CRC)이 25 내지 45 g/g 인, 고흡수성 수지.A superabsorbent polymer having a centrifugal water retention capacity (CRC) of 25 to 45 g/g measured according to EDANA method WSP 241.3.
  15. 제13항에 있어서,The method of claim 13,
    EDANA 법 WSP 242.3에 따라 측정한 0.3 psi의 가압 흡수능(AUL)이 25 내지 40 g/g 인, 고흡수성 수지.A super absorbent polymer having a pressure absorption capacity (AUL) of 0.3 to psi of 25 to 40 g/g measured according to EDANA method WSP 242.3.
  16. 고흡수성 수지 입자; 및Superabsorbent resin particles; And
    플러프 펄프 및 합성 고분자 섬유 중 1종 이상의 섬유를 포함하며,Contains at least one fiber among fluff pulp and synthetic polymer fibers,
    상기 섬유의 적어도 일부는 상기 고흡수성 수지 입자의 내부를 관통하며 혼입되어 있는 것인, 고흡수성 수지 조성물.At least a portion of the fibers are penetrated through the interior of the superabsorbent polymer particles, the superabsorbent polymer composition.
PCT/KR2019/015056 2018-12-11 2019-11-07 Super absorbent polymer and preparation method therefor WO2020122426A1 (en)

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