WO2016148397A1

WO2016148397A1 - Method for preparing superabsorbent polymer

Info

Publication number: WO2016148397A1
Application number: PCT/KR2016/001282
Authority: WO
Inventors: 김지연; 김의덕; 심유진; 오석헌; 이민호; 이혜연
Original assignee: 한화케미칼 주식회사
Priority date: 2015-03-18
Filing date: 2016-02-05
Publication date: 2016-09-22
Also published as: KR20160112220A; TW201700501A; TWI758242B; AR104019A1

Abstract

A method for preparing a superabsorbent polymer comprises the steps of: preparing a base resin by adding at least one among the compounds represented by the following chemical formula (1) to a hydrogel-phase cross-linked polymer; and preparing a superabsorbent polymer by drying the base resin. The method for preparing a superabsorbent polymer can provide a superabsorbent polymer having not undergone surface cross-linking treatment. The superabsorbent polymer having not undergone surface cross-linking treatment has centrifuge retention capacity (CRC) and absorbency under pressure (AUP), which are equivalent to those of a superabsorbent polymer having undergone surface cross-linking treatment, and has extractable content (EC) and remaining monomers (RM), which decrease in comparison with the superabsorbent polymer having undergone surface cross-linking treatment. <Chemical formula (1)> X-(R)_n-Y (In formula, X is an unsaturated hydrocarbon group or a derivative thereof; R is at least one divalent group selected from a C₁-C₅ alkylene group, a C₁-C₄ alkylene oxy group, a C₂-C₆ alkylene (oxy)carbonyl group and a C₂-C₅ carbonyloxy group; n is an integer of 1-20; and Y is a hydrophilic group)

Description

Manufacturing method of super absorbent polymer

The present invention relates to a method for producing a super absorbent polymer.

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

As a method for producing such a super absorbent polymer, a method by reverse phase suspension polymerization or a solution polymerization is known. Reverse phase suspension polymerization is disclosed in, for example, Japanese Patent Laid-Open Nos. 56-161408, 57-158209, and 57-198714. As the method by aqueous solution polymerization, a thermal polymerization method for applying polymerization to an aqueous solution and polymerizing it again, and a photopolymerization method for irradiating and polymerizing ultraviolet rays or the like are known.

In the preparation of the superabsorbent polymer, water-soluble components and residual monomers, which are polymers that are not crosslinked, are produced. The water-soluble component and the residual monomer may show a difference in content depending on the content of the polymerization initiator used during the polymerization, the polymerization temperature, the content of the internal crosslinking agent, the surface crosslinking process conditions, and the like.

When the content of such water-soluble components and residual monomers is high, the surface of the diaper, etc. may become sticky or the liquid permeability may decrease, and may cause skin diseases and odors.

The present invention is to provide a method for producing a super absorbent polymer that can improve the processability by omitting the surface crosslinking process, and can obtain a superabsorbent polymer having reduced water-soluble components and residual monomers compared to the surface-crosslinked superabsorbent polymer. do.

The objects of the present invention are not limited to the above-mentioned technical problem, and other technical problems not mentioned will be clearly understood by those skilled in the art from the following description.

The manufacturing method of the superabsorbent polymer of the present invention is a method of preparing a bare superabsorbent polymer that does not include a surface crosslinking layer, and polymerizing a monomer composition including hydrophilic monomers, a crosslinking agent, and a polymerization initiator to form a hydrogel-like crosslinked polymer. Manufacturing; Preparing a base resin by adding at least one of the compounds represented by the following Formula (1) to the hydrogel-like crosslinked polymer; Drying the base resin; And pulverizing the dry matter. The bare superabsorbent resin may have a water soluble component (EC) of greater than 0% and less than 15%, a residual monomer (RM) of greater than 0 ppm, less than 1000 ppm, preferably greater than 0 ppm and less than 600 ppm.

The method of preparing the super absorbent polymer further includes preparing a monomer composition, and the monomer composition may include the hydrophilic monomers, the crosslinking agent, the polymerization initiator, a neutralizing agent, and a solvent. For example, preparing the monomer composition may include preparing a first composition including the neutralizing agent and the solvent, preparing a second composition including the hydrophilic monomers, the crosslinking agent, and the polymerization initiator. Step and mixing the first composition and the second composition.

The preparing of the hydrogel-like crosslinked polymer may include polymerizing the monomer composition; and pulverizing the hydrogel-like crosslinked polymer.

The polymerization initiator may include a photopolymerization initiator or a complex polymerization initiator, and the complex polymerization initiator may include, for example, the photopolymerization initiator and a thermal polymerization initiator.

X- (R) _n -Y

In the formula (1), X is an unsaturated hydrocarbon group or derivatives thereof, for example, C _2-5 (meth) vinyl group ((meth) vinyl group, CH 2 = CR a -, R a is hydrogen or C _1-3 hydrocarbon group or derivative thereof), C _3-5 (meth) allyl group ((meth) allyl group, CH ₂ = CR _b -CH _2- , R _b is hydrogen or C _1-2 hydrocarbon group or Derivatives thereof), C _1-5 acyl group (R _c C (= 0)-, R _c is hydrogen or a C _1-4 hydrocarbon group or derivative thereof), C _3-5 (meth) Acryloyl group ((meth) acryloyl group, CH ₂ = CR _d -C (= 0)-, R _d is hydrogen or a C _1-2 hydrocarbon group or derivative thereof) and C _3-5 (meth) acrylo A monovalent atomic group or the like of at least one of a (meth) acryloyloxy group (CH ₂ = CR _e -C (= 0) -O-, R _e is hydrogen or a C _1-2 hydrocarbon group or a derivative thereof) have. In a specific example, X may be a C _3-5 (meth) acryloyl group (CH ₂ = CR _d -C (= 0)-, R _d is hydrogen or a C _1-2 hydrocarbon group or a derivative thereof). have.

In the formula (1), R is a C _1-5 alkylene group (-(CH ₂ ) _m- , m is an integer of 1 to 5), C _1-4 alkyleneoxy group,- (CH ₂ ) _m -O-, m is an integer from 1 to 4.), C _2-6 alkylene (oxy) carbonyl group,-(R _f ) _o- (C = O )-(R ' _f ) _p- , o, p are each independently an integer of 0 to 2, at the same time non-zero, R _f , R' _f Are each independently a C _1-5 hydrocarbon group or a derivative thereof) and a C _2-5 carbonyloxy group (-(R _g ) _r- (C = O) -O- (R ' _g ) _s -, r, s are each independently an integer of 0 to 2, at the same time is not 0, R _g , Each R ′ _g is independently a C _1-4 hydrocarbon group or a derivative thereof), and at least one divalent atom group may be used.

n is an integer of 1-20, Y is a hydrophilic group. The hydrophilic group may be, for example, one of a hydroxyl group (-OH), a carboxyl group (-COOH) and an amino group (-NHR _h , -NH ₂ , -NR _h2 , R _h is a C _1-5 hydrocarbon group). have. In a specific example, the hydrophilic group may be a hydroxyl group.

At least one of the compounds represented by the formula (1) may be, for example, at least one of the compounds represented by the following formula (2).

In Formula (2), R ₁ may be _one of hydrogen, a C _1-2 alkyl group and a C _1-2 alkoxy group, and R ₂ may be a C _1-5 alkylene group (-( CH ₂ ) _m −, m is an integer from 1 to 5) and a C _1-5 alkyleneoxy group (— (CH ₂ ) _m —O—, m is an integer from 1 to 5). , Y may be a hydrophilic group. The hydrophilic group may be, for example, one of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amino group (-NHR _h , -NH ₂ , -NR _h2 ).

In Formula (2), n may be an integer of 1 to 20.

At least one of the compounds represented by the formula (2) may be, for example, at least one of the compounds represented by the following formulas (3) to (14).

Specific details of other embodiments are included in the detailed description and the drawings.

In the method of preparing the super absorbent polymer, the surface crosslinking process may be omitted, thereby improving processability.

The manufacturing method of the super absorbent polymer has a lower level of water-soluble component (EC) than the surface crosslinked superabsorbent polymer while exhibiting the same water-retaining capacity (CRC) and pressurized absorbent capacity (AUP) as the surface-crosslinked superabsorbent polymer. And a bare superabsorbent polymer having residual monomer (RM).

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a schematic process flowchart of a method of preparing a super absorbent polymer according to an embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various forms. It is provided to fully convey the scope of the invention to those skilled in the art, the invention being defined only by the scope of the claims.

Although the first, second, etc. are used to describe various components, these components are of course not limited by these terms. These terms are only used to distinguish one component from another.

In the present specification, "surface crosslinked superabsorbent polymer" is defined as a superabsorbent polymer having a core-shell structure in which a base resin is used as a core and a surface crosslinking layer is formed on the surface of the core.

In the present specification, "bare superabsorbent resin" is defined as a superabsorbent polymer in a state where no surface crosslinking layer is formed on the surface of the base resin.

As used herein, "water-containing gel crosslinker" means any one of a sheet-like hydrogel-like crosslinker and a particulate water-containing gel-crosslinker.

In the present specification, "C _AB " is defined as having more than A carbon atoms and less than B, for example, "C _1-5 alkyl group" is an alkyl group having 1 to 5 carbon atoms. As used herein, "C and / or D" is defined to include C, D, or C and D. In the present specification, "E to F" is defined as being equal to or greater than E and equal to or less than F.

In the present specification, "unsaturated hydrocarbon group" is defined as a monovalent atomic group as a residue from which one hydrogen is removed in a hydrocarbon including an unsaturated bond, and may be, for example, a (meth) vinyl group, a (meth) allyl group, or the like. have.

As used herein, an "alkyl group" includes a straight or branched alkyl group and may be, for example, an n-butyl group, a t-butyl group, or the like. As used herein, "(meth) vinyl group" is a univalent group of atoms with a double bond-terminated, CH ₂ = CR _a - may be represented by, a vinyl group R _a is hydrogen, methacrylic vinyl group R _a is an alkyl group or the like Can be. In the present specification, "(meth) allyl group" is a monovalent atomic group having a terminal double bond, which may be represented by CH ₂ = CR _b -CH _2- , and the allyl group is R _b. Is hydrogen, methallyl group and the like R _b is an alkyl group.

As used herein, "derivatives of G" means that in G, for example, in the unsaturated hydrocarbon group, the alkyl group, etc., some or all of the hydrogen comprises atoms other than carbon and hydrogen or atoms other than carbon and hydrogen Atomic groups such as oxygen (O), nitrogen (N), carbonyl group (-(C = O)-), acyl group (R _c C (= O)-), (meth ) Acryloyl group ((meth) acryloyl group, CH ₂ = CR _d -C (= O)-) and the like.

In the present specification, the "alkoxy group" is a monovalent atomic group in which an alkyl group is bonded to oxygen, and is a derivative of an alkyl group, and the alkyl group may be a linear or branched alkyl group. In the present specification, "acyl group" is a monovalent atomic group bonded to a carbonyl group and a hydrocarbon group or a derivative thereof, and may be represented by R _c C (= 0)-and R _d is hydrogen or a C _1-5 hydrocarbon group Or derivatives thereof. In the present specification, "(meth) acryloyl group" is a monovalent atomic group bonded to a (meth) vinyl group and a carbonyl group, and may be represented by CH ₂ = CR _d -C (= O)-, and the acryloyl group R _d is hydrogen and the metacroyl group may be R _d an alkyl group or the like. In the present specification, "(meth) acryloyloxy group" is a monovalent atomic group in which a (meth) acryloyl group is bonded to oxygen, and may be represented by CH ₂ = CR _e -C (= 0) -O-. In the acryloyloxy group, R _e is hydrogen, and in the metacroyloxy group, R _e is an alkyl group or the like.

In the present specification, an "alkylene group" is a residue in which one hydrogen is removed from an alkyl group and is a divalent atomic group consisting of carbon and hydrogen, and may be represented by-(CH ₂ ) _m- , for example, methylene (-CH _2). -), Ethylene (-CH ₂ CH _2- ) and the like. In the present specification, the "alkyleneoxy group" is a divalent atomic group in which one hydrogen is removed from an alkoxy group and the alkylene group is bonded to oxygen, and may be represented by-(CH ₂ ) _m -O-, for example , Methyleneoxy group (-CH ₂ O-, -OCH _2- ), ethyleneoxy group (-CH ₂ CH ₂ O-, -OCH ₂ CH _2- ) and the like. In the present specification, an "alkylene (oxy) carbonyl group" is a divalent atomic group in which two hydrogens are removed from a ketone and an alkylene (oxy) group is bonded to a carbonyl group, and-(R _f ) _o- (C = O)-(R ' _f ) _p- , for example, methylene carbonyl group (-CH _2- (C = O)-), dimethylene carbonyl group (-CH _2- (C = O) -CH _2- ), methyleneoxycarbonyl group (-CH ₂ -O- (C = O)-, -OCH _2- (C = O)-), dimethyleneoxycarbonyl group (-CH ₂ -O- (C = O) -OCH _2- , -OCH _2- (C = O) -CH ₂ -O-) and the like. As used herein, a "carbonyloxy group" is a divalent atomic group in which two hydrogens are removed from an ester and a carbonyl group is bonded to oxygen, and-(R _g ) _r- (C = O) -O- (R ' _g ) _s- , and for example, carbonyloxy group (-(C = O) -O-), methylenecarbonyloxy group (-CH _2- (C = O) -O-) and the like. .

In the present specification, "amino group" is a residue from which one hydrogen is removed from ammonia, and may be represented by -NHR _h , -NH ₂ , -NR _h2 , and R _h may be an alkyl group.

1 is a schematic manufacturing process diagram of a manufacturing method of a super absorbent polymer according to an embodiment of the present invention.

Referring to Figure 1, the method of preparing a super absorbent polymer, the step of preparing a monomer composition (P1), the step of preparing a hydrogel-like crosslinked polymer (P2), the compound represented by the following formula (1) in the hydrogel-like crosslinked polymer Adding at least one of these to prepare a base resin (P3), pulverizing the base resin (P4), drying the pulverized base resin (hereinafter referred to as "pulverized substance") (P5), and Pulverizing the dried base resin (hereinafter referred to as "dry material") (P6).

The step (P2) of preparing the hydrogel-like crosslinked polymer may further include a step (P21) of grinding the hydrogel-like crosslinked polymer, and the step (P21) of grinding the hydrogel-like crosslinked polymer may include preparing a base resin ( P2) may be performed before.

Preparing the monomer composition (P1) includes preparing a first composition comprising a neutralizing agent and a solvent (P11), preparing a second composition including hydrophilic monomers, a crosslinking agent, and a polymerization initiator (P12). And mixing the first composition and the second composition (P13). The monomer composition may include the hydrophilic monomers, the crosslinking agent, the polymerization initiator, the neutralizing agent, and the solvent.

The hydrophilic monomers may be used without limitation as long as the monomers generally used in the production of superabsorbent polymers. The hydrophilic monomers are monomers including a hydrophilic group, and the hydrophilic group is, for example, a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (amino group: -NHR _h , -NH ₂ , -NR _h2 and R _h may be, for example, a C _1-5 alkyl group.) Or the like.

The hydrophilic monomer may be a water-soluble ethylenically unsaturated monomer. The water-soluble ethylenically unsaturated monomer may be at least one of an anionic monomer and a salt thereof, a nonionic hydrophilic-containing monomer, and an amino group-containing unsaturated monomer and a quaternized product thereof.

The anionic monomers and salts thereof are, for example, acrylic acid, methacrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2- ( Meta) acryloylpropanesulfonic acid and at least one of 2- (meth) acrylamide-2-methylpropanesulfonic acid.

Examples of the nonionic hydrophilic-containing monomer include (meth) acrylamide, N-substituted (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, It may be at least one of methoxy polyethylene glycol (meth) acrylate and polyethylene glycol (meth) acrylate.

The amino group-containing unsaturated monomer and its quaternized substance may be, for example, at least one of (N, N) -dimethylaminoethyl (meth) acrylate and (N, N) -dimethylaminopropyl (meth) acrylamide. have.

The concentration of the water-soluble ethylenically unsaturated monomer in the monomer composition may be appropriately selected and used in consideration of polymerization time and reaction conditions (feed rate of the monomer composition, irradiation time of heat and / or light, irradiation range, irradiation intensity, etc.). In an exemplary embodiment, the weight ratio may be in a range of 30 wt% or more and 60 wt% or less.

The crosslinking agent may include one or more atomic groups and ethylenically unsaturated groups each capable of reacting with the functional group of the hydrophilic monomer, or an atomic group capable of reacting with the functional group formed by hydrolyzing the functional group of the hydrophilic monomer and the hydrophilic monomer. The compound containing two or more can be used.

In one non-limiting example, the crosslinking agent is C _8-12 bisacrylamide, C _8-12 bismethacrylamide, poly (meth) acrylate of C _2-12 polyol or poly (meth) allyl of C _2-10 polyol Ether and the like.

In a specific example, the crosslinking agent is (poly) ethylene glycol (meth) acrylate, (poly) propylene glycol di (meth) acrylate, trimethylol propane tri (meth) acrylate, ethoxyl (3) -trimethylol propane Tri (meth) acrylate, ethoxyl (6) -trimethylolpropane tri (meth) acrylate, ethoxyl (9) -trimethylolpropane tri (meth) acrylate, ethoxyl (15) -trimethylolpropane tree ( Meta) acrylate glycerin tri (meth) acrylate, glycerin acrylate methacrylate, 2,2-bis [(acryloxy) methyl] butyl acrylate (3EO), N, N'-methylene bis (meth) acrylate , Ethyleneoxy (meth) acrylate, polyethyleneoxy (meth) acrylate, propyleneoxy (meth) acrylate, glycerin, glycerin diacrylate, glycerin triacrylate, trimethol triacrylate, trial Although arylamine, triaryl cyanurate, triallyl isocyanate, pentaethyleneimine, ethylene glycol, polyethyleneglycol diethylene glycol, propylene glycol, or a mixture of 2 or more types thereof is mentioned, It is not limited to these.

In a non-limiting example, the crosslinking agent may be included in the range of 0.01 parts by weight to 0.5 parts by weight based on 100 parts by weight of the hydrophilic monomer, but is not limited thereto.

The polymerization initiator may be at least one of a photopolymerization initiator, a thermal polymerization initiator, and an oxidation-reduction initiator. The polymerization initiator may be a complex polymerization initiator containing two or more kinds of polymerization initiators. For example, the complex polymerization initiator may include the photopolymerization initiator and the thermal polymerization initiator. In addition, for example, the complex polymerization initiator may include the thermal polymerization initiator and the oxidation-reduction initiator.

The photopolymerization initiator initiates photopolymerization of the monomer composition when irradiated with ultraviolet light, the thermal polymerization initiator initiates thermal polymerization of the monomer composition by heating, and the oxidation-reduction initiator reacts to an oxidation-reduction reaction. The polymerization of the monomer composition can be started. When the photopolymerization initiator and the thermal polymerization initiator are used together, polymerization by the thermal polymerization initiator may occur by heat generated during photopolymerization. When the oxidation-reduction initiator and the thermal polymerization initiator are together, the thermal polymerization initiator may be initiated together with the heat generated during the oxidation-reduction reaction to cause polymerization.

For example, the polymerization initiator is diethoxy acetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4- (2-hydroxy ethoxy) phenyl- (2-hydroxy)- Acetophenone derivatives such as 2-propyl ketone and 1-hydroxycyclohexylphenyl ketone; Benzoin alkyl ether compounds such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzophenone derivatives such as methyl o-benzoyl benzoate, 4-phenyl benzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, and (4-benzoyl benzyl) trimethylammonium chloride; Thioxanthone compounds; Acyl phosphine oxide derivatives such as bis (2,4,6-trimethylbenzoyl) -phenyl phosphine oxide and diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide; Or azo systems such as 2-hydroxy methyl propionitrile and 2,2 '-(azobis (2-methyl-N- (1,1'-bis (hydroxymethyl) -2-hydroxyethyl) propion amide) Compounds; azo initiators; peroxide initiators; redox initiators; organic halide initiators; sodium persulfate (Na ₂ S ₂ O ₈ ); Potasium persulfate (K ₂ S) ₂ O ₈ ); or mixtures thereof, but is not limited thereto.

If the polymerization initiator can exhibit a polymerization initiation effect, its content may be appropriately selected. In a non-limiting example, the photopolymerization initiator may be included in the monomer composition in a range of 0.005 parts by weight to 0.5 parts by weight based on 100 parts by weight of the hydrophilic monomers, and the thermal polymerization initiator may be included in 100 parts by weight of the hydrophilic monomers. It may be included in the monomer composition in the range of 0.01 parts by weight to 0.5 parts by weight.

The neutralizing agent may serve to neutralize the hydrophilic monomer. Representative neutralizing agents include, but are not limited to, sodium hydroxide, sodium bicarbonate, and the like. The neutralizing agent may be used in the range that the degree of neutralization of the monomer composition is 65 mol% to 75 mol%. However, this is not limited only.

The solvent may be water, and water may serve as a polymerization medium.

Step (P2) of preparing the hydrogel-like crosslinked polymer may include polymerizing the monomer composition (P21) and pulverizing the sheet-like hydrogel-like crosslinked polymer (P22).

Polymerizing the monomer composition (P21) is a step of performing a photopolymerization reaction and / or thermal polymerization by applying light and / or heat to the monomer composition. For example, when the ultraviolet rays are irradiated onto the monomer composition, a photopolymerization reaction may be initiated by the photopolymerization initiator. When the monomer composition includes both the photopolymerization initiator and the thermal polymerization initiator, the thermal polymerization initiator may initiate a thermal polymerization reaction by heat generated during the photopolymerization reaction. The polymerization reaction can be carried out, for example, using a belt type polymerization reactor, and a sheet-like hydrogel-like crosslinked polymer can be obtained by the polymerization reaction.

The step of pulverizing a sheet-like hydrogel-like crosslinker (P22) is to grind or crush the sheet-like hydrogel-like crosslinker into a particulate hydrogel-like crosslinker having a particle size of about 1 cm to about 3 cm. The water content can be, for example, about 40% to about 60% by weight.

After preparing the hydrogel-like crosslinked polymer (P2), a base resin is prepared by adding at least one of the compounds represented by the following Formula (1) to the hydrogel-like crosslinked polymer, preferably particulate hydrogel-like crosslinked polymer. Step P3 is performed.

At least one of the compounds represented by the following formula (1) may react with an uncrosslinked linear polymer chain to lower the value of the extractable content (EC) and react with unreacted monomers. The level of residual monomer (RM) can be lowered.

X- (R) _n -Y

In the above formula (1), X is an unsaturated hydrocarbon group or a derivative thereof.

In the formula (1), R is a C _1-5 alkylene group (-(CH ₂ ) _m- , m is an integer of 1 to 5), C _1-4 alkyleneoxy group,- (CH ₂ ) _m -O-, m is an integer from 1 to 4.), C _2-6 alkylene (oxy) carbonyl group,-(R _f ) _o- (C = O )-(R ' _f ) _p- , o, p are each independently an integer of 0 to 2, at the same time non-zero, R _f , R' _f Are each independently a C _1-5 hydrocarbon group or a derivative thereof) and a C _2-5 carbonyloxy group (-(R _g ) _r- (C = O) -O- (R ' _g ) _s- , r, s are each independently an integer of 0 to 2, and at the same time is not 0, R _g , Each R ′ _g is independently a C _1-4 hydrocarbon group or derivative thereof).

In the formula (1), n is an integer of 1 to 20, Y is a hydrophilic group. The hydrophilic group may react with the unreacted monomers and the linear polymer chain to form a hydrogen bond.

X is, for example, a C _2-5 (meth) vinyl group (CH ₂ = CR _a −, R _a is hydrogen or a C _1-3 hydrocarbon group or a derivative thereof), C _3-5 (meth) allyl group ((meth) allyl group, CH ₂ = CR _b -CH _2- , R _b is hydrogen or C _1-2 hydrocarbon group or derivative thereof), C _1-5 acyl group ( acyl group, R _c C (═O) —, R _c is hydrogen or a C _1-4 hydrocarbon group or derivative thereof), C _3-5 (meth) acryloyl group ((meth) acryloyl group, CH ₂ = CR _d -C (= 0)-, R _d is hydrogen or a C _1-2 hydrocarbon group or derivative thereof) and C _3-5 (meth) acryloyloxy group (CH ₂ = CR _e -C (= 0) -O-, R _e is hydrogen or a C _1-2 hydrocarbon group or derivative thereof. In a specific example, X may be a C _3-5 (meth) acryloyl group (CH ₂ = CR _d -C (= 0)-, R _d is hydrogen or a C _1-2 hydrocarbon group or a derivative thereof). have.

Y may be, for example, one of a hydroxyl group (-OH), a carboxyl group (-COOH), and an amino group (-NHR _h , -NH ₂ , -NR _h2 , R _h is a C _1-5 hydrocarbon group). have. In a specific example, Y may be a hydroxyl group.

At least one of the compounds represented by the formula (1) may improve the reactivity with the hydrous gel-like crosslinked polymer that is hydrophilic in the range of the carbon number and the value of n of the R. On the other hand, when the carbon number of the R is increased or the n value is increased, the hydrophobicity may be increased to decrease the reactivity with the hydrophilic hydrogel-like crosslinked polymer.

The content of at least one of the compounds represented by the formula (1) may be in the range of 1% by weight to 10% by weight based on the total weight of the bare superabsorbent resin. At least one of the compounds represented by the formula (1) has a low level of the water-soluble component (EC) and the residual monomer (RM) at a lower level than the conventional surface cross-linked super absorbent polymer within the above-described content range. The value can be lowered and can exhibit the same level of water retention (CRC) as the surface-crosslinked superabsorbent polymer.

At least one of the compounds represented by the formula (1) may be, for example, at least one of the compounds represented by the following formula (2):

In Formula (2), R ₁ may be _one of hydrogen, a C _1-2 alkyl group and a C _1-2 alkoxy group, and R ₂ may be a C _1-5 alkylene group (-( CH ₂ ) _m −, m is an integer from 1 to 5) and a C _1-5 alkyleneoxy group (— (CH ₂ ) _m —O—, m is an integer from 1 to 5). , Y may be one of a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (-NHR _h , -NH ₂ , -NR _h2 ). In the formula (2), n is an integer of 1 to 20. The carbon double bond (C = C) in the (meth) acryloyl group may be chemically bonded to the unreacted monomer and the linear polymer chain without steric hindrance within the carbon number of R ₁ .

At least one of the compounds represented by the formula (2) may be, for example, at least one of the compounds represented by the following formulas (3) to (14):

Crushing the base resin (P4) is to heavy chain the base resin into particles having a particle diameter of millimeters (mm). The step P4 of crushing the base resin may be performed using, for example, a cutter type cutter, a chopper type cutter, a kneader type cutter, a vibratory grinder, an impact grinder, a friction grinder, or the like.

Drying the milled product (P5) may be carried out in a range of about 20 minutes to about 40 minutes at a temperature of about 150 ℃ to about 200 ℃. Drying the pulverized product (P5) may be performed using, for example, a hot air dryer, a fluidized bed dryer, an airflow dryer, an infrared dryer, a dielectric heating dryer, or the like.

The step (P6) of pulverizing the dry matter is to pulverize the dry matter into particles having an average particle diameter of micrometer (μm), and may include a process of selecting particles having an average particle diameter of 150 μm to 850 μm.

The manufacturing method of the super absorbent polymer may provide a bare super absorbent polymer. The bare superabsorbent polymer may have a level of water retention (Centrifuge Retention Capacity (CRC) and Absorbency Under Pressure (AUP)) equivalent to that of the surface crosslinked superabsorbent polymer, and may be applied to the surface crosslinked superabsorbent polymer. It may have a lower level of extractable content (EC) and residual monomer (RM).

This will be described in detail with reference to the following Examples and Experimental Examples.

After mixing 77.778 g of 50% aqueous sodium hydroxide solution (NaOH) and 88.84 g of water, 100 g of acrylic acid, 0.115 g of polyethylene glycol diacrylate (Mw = 400) as a crosslinking agent, 2,2-bis [(acryloxy) methyl] butyl acryl 0.115 g of rate (3EO) and 0.033 g of diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide were mixed with a photoinitiator to prepare a monomer composition having a concentration of 45% by weight of the hydrophilic monomer.

In 8.67 g of water, 1.33 g of Potassium persulfate, a thermal initiator, was dissolved, and 3.008 g was mixed in the monomer composition.

Thereafter, the monomer composition was introduced into a polymerizer consisting of a conveyor belt continuously moving at a temperature of 40 ° C., and then irradiated with ultraviolet rays (irradiation amount: 9 mW / cm 2) through a UV irradiation apparatus, followed by UV polymerization for 3 minutes, to obtain a sheet-like function. Gel-like crosslinked polymers were prepared.

The sheet-like hydrogel polymer was transferred to a cutter and cut into 2 cm. At this time, the water content of the cut hydrogel-like crosslinked polymer was 50% by weight.

The monomer composition using 0.033 g of diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide and 2.256 g of aqueous solution of Potassium persulfate was fed to a polymerizer consisting of a conveyor belt continuously moving at a temperature of 30 ° C. for 2 minutes. A particulate hydrogel-like crosslinked polymer was prepared in the same manner as in Preparation Example 1, except that ultraviolet ray was irradiated.

The monomer composition using 0.033 g of diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide and 2.256 g of aqueous solution of Potassium persulfate was fed to a polymerizer consisting of a conveyor belt continuously moving at a temperature of 20 ° C., for 2 minutes. A particulate hydrogel-like crosslinked polymer was prepared in the same manner as in Preparation Example 1, except that ultraviolet ray was irradiated.

2 g of the ethoxylated (6) methacrylate ester compound (Bisomer PEM6LD) was uniformly sprayed onto 100 g of the particulate hydrogel-like crosslinked polymer of Preparation Example 1, and then chopped using a meat chopper. Then, the pulverized particulate hydrogel polymer was dried in a hot air dryer at 180 ° C. for 30 minutes, and the dried particulate hydrogel polymer was pulverized with a pin mill grinder. Thereafter, a bare superabsorbent polymer having an average particle size of 150 to 850 µm was manufactured using a sieve.

A bare superabsorbent polymer was prepared in the same manner as in Example 1, except that 1 g of an ethoxylated (6) methacrylate ester compound (Bisomer PEM6LD) was uniformly sprayed onto 100 g of a particulate hydrogel-like crosslinked polymer of Preparation Example 2.

A bare superabsorbent polymer was prepared in the same manner as in Example 1, except that 2 g of an ethoxylated (6) methacrylate ester compound (Bisomer PEM6LD) was uniformly sprayed onto 100 g of a particulate hydrogel-like crosslinked polymer of Preparation Example 2.

A bare superabsorbent polymer was prepared in the same manner as in Example 1, except that 2 g of an ethoxylated (6) methacrylate ester compound (Bisomer PEM6LD) was uniformly sprayed onto 100 g of a particulate hydrogel-like crosslinked polymer of Preparation Example 3.

The particulate hydrogel-like crosslinked polymer of Preparation Example 1 was chopped using a meat chopper. Subsequently, the pulverized particulate hydrogel-like crosslinked polymer was dried in a hot air dryer at 180 ° C. for 30 minutes, and the dried particulate hydrogel-like crosslinked polymer was ground with a pin mill grinder. Thereafter, a bare superabsorbent polymer having an average particle size of 150 to 850 µm was obtained using a sieve. The bare superabsorbent polymer thus obtained was sprayed onto the powder at a rate of 5 pph with a 20% aqueous solution of ethylene carbonate in a surface crosslinking mixer, and dried again at 180 ° C. for 30 minutes. The dried bare superabsorbent resin was classified into a standard mesh of ASTM standard to prepare a supercrosslinked superabsorbent polymer having a particle diameter of 150 µm to 850 µm.

A superabsorbent polymer having a surface crosslinking treatment was prepared in the same manner as in Comparative Example 1 except that the particulate hydrogel type crosslinked polymer of Preparation Example 2 was used instead of the particulate hydrogel type crosslinked polymer of Preparation Example 1.

A superabsorbent polymer having a surface crosslinking treatment was prepared in the same manner as in Comparative Example 1 except that the particulate hydrogel type crosslinked polymer of Preparation Example 3 was used instead of the particulate hydrogel type crosslinked polymer of Preparation Example 1.

After mixing 77.778 g of 50% aqueous sodium hydroxide solution (NaOH) and 88.84 g of water, 100 g of acrylic acid and 0.115 g of polyethylene glycol diacrylate (Mw = 400) were used as a crosslinking agent, and 2,2-bis [(acryloxy) methyl] butyl 0.115 g of acrylate (3EO), 0.033 g of diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide as photoinitiator, ethoxylated with comonomer (6) methacrylate ester compound (Bisomer PEM6LD 2g) was mixed to prepare a monomer composition having a concentration of 45% by weight of the hydrophilic monomer.

Thereafter, the monomer composition was introduced into a polymerizer composed of a conveyor belt continuously moving at a temperature of 40 ° C., and then irradiated with ultraviolet rays (irradiation amount: 9 Mw / cm ² ) through a UV irradiation apparatus, followed by UV polymerization for 3 minutes to form a sheet. A hydrogel-like crosslinked polymer was prepared.

The sheet-like hydrogel-like crosslinked polymer was transferred to a cutter and cut into 2 cm. At this time, the water content of the cut particulate hydrogel-like crosslinked polymer was 50% by weight.

Subsequently, the particulate hydrogel-like crosslinked polymer was dried in a hot air dryer at 180 ° C. for 30 minutes, and the dried particulate hydrogel-based crosslinked polymer was ground in a pin mill grinder. Thereafter, a bare superabsorbent polymer having an average particle diameter of 150 µm to 850 µm was obtained using a sieve.

Experimental Example 1

The unreacted monomers of the particulate hydrogel-like crosslinked polymers prepared in Preparation Examples 1 to 3 were measured, and the results are shown in Table 1.

	미반응 모노머 (ppm)Unreacted monomer (ppm)
제조예 1Preparation Example 1	60406040
제조예 2Preparation Example 2	1808018080
제조예 3Preparation Example 3	4600046000

Experimental Example 2

Compared to the bare superabsorbent resins obtained in Examples 1 to 4 and the surface crosslinked superabsorbent resins obtained in Examples 1 to 3, water-retaining capacity (CRC), water-soluble component (EC), pressure-absorbing capacity (AUP) and residual The monomer (RM) was measured and the results are shown in Table 2 below. CRC was measured according to the European Disposables and Nonwovens Association (EDANA) WSP241.2.R3 method. The water soluble component (EC) was measured according to the European Disposables and Nonwovens Association (EDANA) WSP270.2.R3 method. Pressurized absorbent capacity (AUP) is the European Disposables and Nonwovens Association (EDANA) WSP 242.2. It measured according to the R3 method. Residual monomers (RM) are the European Disposables and Nonwovens Association (EDANA) WSP 210.2. It measured according to the R3 method.

	CRC (g/g)CRC (g / g)	EC (%)EC (%)	AUP (g/g)AUP (g / g)	RM (ppm)RM (ppm)
실시예1Example 1	3030	1414	1111	195195
실시예2Example 2	3636	1010	1818	469469
실시예3Example 3	3232	1010	2020	395395
실시예4Example 4	3030	99	2020	572572
비교예1Comparative Example 1	3030	1616	2020	360360
비교예2Comparative Example 2	3333	1717	1818	654654
비교예3Comparative Example 3	3535	1919	1717	890890
비교예4Comparative Example 4	2424	77	2020	11201120

Referring to Table 2, the bare superabsorbent polymers obtained in the examples have lower levels of water-soluble components (EC) and residual monomers (RM) than the surface-crosslinked superabsorbent polymers obtained in the corresponding comparative examples, respectively. Able to know.

The bare superabsorbent polymers obtained in Examples 2 to 4 using hydrous gel-like crosslinked polymers having a large amount of unreacted monomers were treated with the surface crosslinked superabsorbent polymers obtained in Comparative Examples 1 to 3, which were subjected to the surface crosslinking process even though the surface crosslinking process was not performed. It can be seen that the water holding capacity (CRC) and the pressure absorption capacity (AUP) are equivalent.

On the other hand, the bare superabsorbent resins obtained in Examples are superior in water-retaining ability and less residual monomer (RM) content than the bare superabsorbent resins obtained in Comparative Example 4.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be manufactured in various forms, and a person of ordinary skill in the art to which the present invention pertains has the technical idea of the present invention. However, it will be understood that other specific forms may be practiced without changing the essential features. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

Preparing a hydrogel-like crosslinked polymer by polymerizing a monomer composition comprising hydrophilic monomers, a crosslinking agent and a polymerization initiator;

Preparing a base resin by adding at least one of the compounds represented by the following Formula (1) to the hydrogel-like crosslinked polymer;

Drying the base resin; And

Grinding the dry matter;

Method for producing a bare (super absorbent) resin comprising a.

<Formula (1)>

X- (R) n -Y

In the above formula (1),

X is an unsaturated hydrocarbon group or derivative thereof,

R is a C 1-5 alkylene group (-(CH 2 ) m- , m is an integer from 1 to 5), C 1-4 alkyleneoxy group (-(CH 2 ) m -O m is an integer of 1 to 4.), C 2-6 alkylene (oxy) carbonyl group,-(R f ) o- (C = O)-(R ' f ) p- , o, p are each independently an integer of 0 to 2, at the same time non-zero, R f , R ' f Are each independently a C 1-5 hydrocarbon group or a derivative thereof) and a C 2-5 carbonyloxy group (-(R g ) r- (C = O) -O- (R ' g ) s- , r, s are each independently an integer of 0 to 2, and at the same time is not 0, R g , Each R ′ g is independently a C 1-4 hydrocarbon group or derivative thereof), and is a divalent atom group of at least one of

n is an integer from 1 to 20,

Y is a hydrophilic group.
According to claim 1,

X is a C 2-5 (meth) vinyl group (CH 2 = CR a −, R a is hydrogen or a C 1-3 hydrocarbon group or a derivative thereof), C 3-5 (meth Allyl group ((meth) allyl group, CH 2 = CR b -CH 2- , R b is hydrogen or C 1-2 hydrocarbon group or derivative thereof), C 1-5 acyl group (R c C (= O) -., R c is hydrogen or a C 1-4 hydrocarbon group or derivatives thereof), (diary meth) acrylate ((meth) C 3-5 acryloyl group , CH 2 = CR d -C ( = O)-, R d is hydrogen or a C 1-2 hydrocarbon group or derivative thereof.) And C 3-5 (meth) acryloyloxy group (CH 2 = CR e -C (= O) -O-, R e is hydrogen or a C 1-2 hydrocarbon group or a derivative thereof.) A method for producing a bare superabsorbent resin, wherein at least one monovalent atomic group is used.
According to claim 1,

Y is one of hydroxyl group (-OH), carboxyl group (-COOH) and amino group (-NHR h , -NH 2 , -NR h2 , R h is a C 1-5 hydrocarbon group) Way.
According to claim 1,

X is a C 3-5 (meth) acryloyl group (CH 2 = CR d -C (= O)-, R d is hydrogen or a C 1-2 hydrocarbon group or a derivative thereof) of the bare superabsorbent resin Manufacturing method.
According to claim 1,

At least one of the compounds represented by the formula (1) is at least one of the compounds represented by the formula (2) method of producing a bare superabsorbent resin:

<Formula (2)>

In the above formula (2),

R 1 is one of hydrogen, a C 1-2 alkyl group and a C 1-2 alkoxy group,

R 2 is a C 1-5 alkylene group (-(CH 2 ) m- , m is an integer of 1 to 5) and a C 1-5 alkyleneoxy group (-(CH 2 ) m -O-, m is 1 To an integer of 5).

Y is one of a hydroxyl group (-OH), a carboxyl group (-COOH), an amino group (-NHR h , -NH 2 , -NR h2 ),

n is an integer of 1-20.
The method of claim 5,

At least one of the compounds represented by the formula (2) is at least one of the compounds represented by the following formulas (3) to (14) method for producing a bare superabsorbent resin:

<Formula (3)>

<Formula (4)>

<Formula (5)>

<Formula (6)>

<Formula (7)>

<Formula (8)>

<Formula (9)>

<Formula (10)>

<Formula 11>

<Formula 12>

<Formula (13)>

<Formula 14>
According to claim 1,

Preparing a monomer composition; further comprising, preparing the monomer composition;

Preparing a first composition comprising a neutralizing agent and a solvent, preparing a second composition comprising the hydrophilic monomers, the crosslinking agent, and the polymerization initiator, and mixing the first composition with the second composition Bare superabsorbent polymer manufacturing method comprising a.
According to claim 1,

The polymerization initiator comprises a photopolymerization initiator or a complex polymerization initiator, wherein the complex polymerization initiator is a method of producing a bare superabsorbent resin comprising the photopolymerization initiator and a thermal polymerization initiator.
According to claim 1,

The preparing of the hydrogel-like crosslinked polymer may include: polymerizing the monomer composition; and pulverizing the hydrogel-like crosslinked polymer.
According to claim 1,

The bare superabsorbent polymer has a water-soluble component (EC) of more than 0% and less than 15%, and a residual monomer (RM) of more than 0 ppm and less than 1000 ppm.
The method of claim 10,

The bare superabsorbent polymer has a water soluble component (EC) of more than 0% and less than 15%, and a residual monomer (RM) of more than 0 ppm and less than 600 ppm.