WO2020149651A1 - Procédé de préparation d'un polymère superabsorbant - Google Patents

Procédé de préparation d'un polymère superabsorbant Download PDF

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WO2020149651A1
WO2020149651A1 PCT/KR2020/000761 KR2020000761W WO2020149651A1 WO 2020149651 A1 WO2020149651 A1 WO 2020149651A1 KR 2020000761 W KR2020000761 W KR 2020000761W WO 2020149651 A1 WO2020149651 A1 WO 2020149651A1
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particles
meth
polymer
acrylate
grinding
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Korean (ko)
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우희창
송종훈
김기철
민윤재
김재율
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주식회사 엘지화학
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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
    • C08F8/00—Chemical modification by after-treatment
    • 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

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  • the present invention relates to a method for producing a super absorbent polymer capable of suppressing and reducing the generation of fine powder.
  • Super Absorbent Polymer is a synthetic polymer material that has the ability to absorb about 500 to 1,000 times its own weight.Sam (Super Absorbency Material), AGM (Absorbent Gel) for each developer Material).
  • the superabsorbent resin as described above began to be put into practical use as a sanitary tool, and now, in addition to sanitary products such as paper diapers for children, soil repair agents for horticulture, civil engineering, construction water supply materials, nursery sheets, freshness retention agents in the food distribution field, and It is widely used as a material for poultice. In most cases, these superabsorbent polymers are widely used in the field of hygiene materials such as diapers and sanitary napkins.
  • the superabsorbent polymer is prepared through a process of preparing a hydrogel polymer using a water-soluble ethylenically unsaturated monomer, followed by drying and pulverization. In this process, particles having a particle diameter of 150 ⁇ m or less are inevitably generated. Is becoming. These fine powders are known to occur at a rate of about 20 to 30% during the pulverization or transfer process during the manufacturing process of the super absorbent polymer. Since the fine powder affects the pressure absorbing capacity (AUP) and permeability of the super absorbent polymer, it is difficult to produce a super absorbent polymer having both properties simultaneously increased. For this reason, during the manufacturing process of the super absorbent polymer, particularly in the classification process, these fine powders are separated to produce the super absorbent polymer only with the remaining polymer particles.
  • AUP pressure absorbing capacity
  • permeability of the super absorbent polymer it is difficult to produce a super absorbent polymer having both properties simultaneously increased. For this reason, during the manufacturing process of the super absorb
  • the milling of the roll mill is excessively carried out to realize the particle size distribution, and accordingly, the fine powder of less than 150 ⁇ m is greatly increased. As a result, the ratio of fines recycling in the process is maintained. Therefore, the method has a problem in that the load of the drying/grinding/classifying process increases and the production amount decreases.
  • the present invention is to provide a method for manufacturing a superabsorbent polymer and an apparatus for producing a superabsorbent polymer capable of reducing and suppressing the generation of fine powder while maintaining excellent properties of the superabsorbent polymer.
  • the present invention (A) in the presence of an internal crosslinking agent and a polymerization initiator, at least a part of the polymerization step of crosslinking polymerization of a water-soluble ethylenically unsaturated monomer having an acidic group neutralized to form a hydrogel polymer; (B) a drying step of drying the hydrogel polymer to prepare a dry polymer; And (C) a grinding step of grinding the dry polymer;
  • the (C) grinding step includes (C1) a first grinding step and (C2) a second grinding step to pulverize the dry polymer, and (C2) the second grinding step is (C21) the An abnormal particle classification step of classifying the primary pulverized dry polymer into'abnormal particles' having a particle diameter equal to or larger than the target particle diameter and'normal particles' having a particle diameter smaller than the target particle diameter; And (C22) provides a method for producing a super absorbent polymer, comprising the step of pulverizing the abnormal particles, collecting and crushing
  • the present invention is an input unit 100 to which the dry polymer is added; A crushing unit 200 for pulverizing the introduced dry polymer; And an outlet portion 300 for discharging the pulverized dry polymer particles;
  • the crushing unit 200 includes a first crushing unit 210 and a second crushing unit 220 for pulverizing the dried polymer, and the second crushing unit 220 is the first An abnormal particle classifying portion 221 for classifying the dried polymer pulverized in the primary crushing unit 210 into'abnormal particles' having a particle diameter equal to or larger than the target particle diameter and'normal particles' having a particle diameter smaller than the target particle diameter; And an abnormal particle pulverization portion 222 that collects only the “abnormal particles” and pulverizes again.
  • polymer or “polymer” as used in the specification of the present invention means that the water-soluble ethylenically unsaturated monomer is in a polymerized state, and may cover all water content ranges or particle size ranges.
  • a polymer having a water content (moisture content) of about 40% by weight or more as a state after drying after polymerization may be referred to as a hydrogel polymer.
  • “superabsorbent polymer” means the polymer or base resin itself depending on the context, or additional processes for the polymer or the base resin, such as surface crosslinking, fine powder reassembly, drying, grinding, classification, etc. It is used to cover everything that has been made suitable for commercialization.
  • the (C) grinding step includes (C1) a first grinding step and (C2) a second grinding step to pulverize the dry polymer, and (C2) the second grinding step is (C21) the An abnormal particle classification step of classifying the primary pulverized dry polymer into'abnormal particles' having a particle diameter equal to or larger than the target particle diameter and'normal particles' having a particle diameter smaller than the target particle diameter; And (C22) a method for producing a super absorbent polymer, comprising the steps of pulverizing the abnormal particles, collecting
  • the method for producing a superabsorbent polymer according to the present invention in the process of forming and drying a hydrogel polymer, pulverizing and then classifying the dried dry polymer, crushing and classifying again only for particles having a certain size or more after the crushing step, preferably By pulverizing and classifying repeatedly about 2 or more times, or 2 to 5 times, or 2 to 4 times, or 3 to 4 times, particles of a certain size or less are prevented from being crushed together, and the particle size is about 150 ⁇ m. It is possible to minimize the amount of the following fine powder.
  • the present invention after pulverization, since the classification process using a classifier is essential, it is possible not only to reduce the amount of fines generated, but also to control the particle size according to the particle size in the classifier, so that the particle size of the final product can be easily adjusted. It is possible to provide a method for producing a superabsorbent polymer having physical properties equal to or higher than those of the prior art.
  • the present invention reduces the amount of fines generated by controlling the degree of separation by setting the separation target according to the particle size of the classifier during crushing, that is, the target particle size, thereby reducing the load of the fine powder reassembly, drying, pulverization and classification process.
  • the separation target according to the particle size of the classifier during crushing, that is, the target particle size
  • the target target particle size means a particle size that is a standard for classification for separating normal particles and abnormal particles in the abnormal particle classification step of the second grinding step.
  • the particles in a specific size range are classified through classification in each crushing step, and small-sized particles (for example, about By separating particles having a particle diameter of 200 ⁇ m or less, or about 150 ⁇ m or less), it is possible to selectively exclude such particles from being re-introduced into grinding.
  • the present invention is to arbitrarily select the size of the classifier used in this process according to the target particle size, easily adjust the particle size of the particles used in the final product to a specific range, thereby changing the properties of the super absorbent polymer. Can.
  • the polymerization step is a step of forming a hydrogel polymer, and is a step of crosslinking and polymerizing a monomer composition comprising an internal crosslinking agent and a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acidic group.
  • the water-soluble ethylenically unsaturated monomer constituting the first crosslinked polymer may be any monomer commonly used in the production of super absorbent polymers.
  • the water-soluble ethylenically unsaturated monomer may be a compound represented by Formula 1 below:
  • R 1 is an alkyl group having 2 to 5 carbon atoms containing an unsaturated bond
  • M 1 is a hydrogen atom, a monovalent or divalent metal, an ammonium group or an organic amine salt.
  • the monomer may be at least one selected from the group consisting of acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids.
  • acrylic acid or a salt thereof is used as the water-soluble ethylenically unsaturated monomer, it is advantageous to obtain a superabsorbent polymer with improved absorbency.
  • the monomers include maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2-(meth)acryloylpropanesulfonic acid or 2-(metha) )Acrylamide-2-methyl propane sulfonic acid, (meth)acrylamide, N-substituted (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxypolyethylene Glycol (meth)acrylate, polyethylene glycol (meth)acrylate, (N,N)-dimethylaminoethyl (meth)acrylate, (N,N)-dimethylaminopropyl (meth)acrylamide, and the like can be used.
  • the water-soluble ethylenically unsaturated monomer has an acidic group, and at least a portion of the acidic group may be neutralized.
  • the monomer may be partially neutralized with an alkali material such as sodium hydroxide, potassium hydroxide or ammonium hydroxide.
  • the degree of neutralization of the monomer may be about 40 to about 95 mol%, or about 40 to about 80 mol%, or about 45 to about 75 mol%.
  • the range of the degree of neutralization may vary depending on the final physical properties, but if the degree of neutralization is too high, the neutralized monomer may be precipitated and polymerization may be difficult to proceed smoothly. It may exhibit properties such as elastic rubber that are difficult to handle.
  • the concentration of the water-soluble ethylenically unsaturated monomer in the monomer composition may be appropriately adjusted in consideration of polymerization time and reaction conditions, and preferably about 20 to about 90% by weight, or about 40 to about 65% by weight Can.
  • This concentration range may be advantageous for controlling the grinding efficiency when pulverizing the polymer, which will be described later, while eliminating the need to remove unreacted monomers after polymerization by using the gel effect phenomenon that occurs in the polymerization reaction of a high concentration aqueous solution.
  • the concentration of the monomer is too low, the yield of the super absorbent polymer may be lowered.
  • the concentration of the monomer is too high, a part of the monomer may be precipitated or there may be a process problem such as poor crushing efficiency when pulverizing the polymerized hydrogel polymer, and physical properties of the super absorbent polymer may be deteriorated.
  • the internal crosslinking agent any compound can be used as long as it allows introduction of crosslinking during polymerization of the water-soluble ethylenically unsaturated monomer.
  • the internal crosslinking agent is N,N'-methylenebisacrylamide, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol (meth)acrylate, propylene glycol di( Meth)acrylate, polypropylene glycol (meth)acrylate, butanediol di(meth)acrylate, butylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, hexanediol di(meth) )Acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipentaerythritol pentaacrylate,
  • the internal crosslinking agent may be added in a concentration of about 0.001 to about 1% by weight relative to the monomer composition. That is, when the concentration of the internal crosslinking agent is too low, the absorption rate of the resin is lowered and the gel strength may be weakened, which is not preferable. Conversely, when the concentration of the internal cross-linking agent is too high, the absorbency of the resin is lowered, which may make it undesirable as an absorber.
  • a polymerization initiator generally used in the production of a super absorbent polymer may be included.
  • a thermal polymerization initiator or a photo polymerization initiator may be used depending on the polymerization method, and a thermal polymerization initiator may be used.
  • a thermal polymerization initiator may be additionally included.
  • thermal polymerization initiator one or more compounds selected from the group consisting of a persulfate-based initiator, an azo-based initiator, hydrogen peroxide, and ascorbic acid may be used.
  • a persulfate-based initiator sodium persulfate (Na 2 S 2 O 8 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate (A mmonium persulfate; (NH 4 ) 2 S 2 O 8 ) and the like.
  • 2,2-azobis-(2-amidinopropane) dihydrochloride (2,2-azobis(2-amidinopropane) dihydrochloride), 2,2-azobis-(N, N-dimethylene)isobutyramidine dihydrochloride (2,2-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, For example, 4-azobis-(4-cyanovaleric acid) (4,4-azobis-(4-cyanovaleric acid)).
  • thermal polymerization initiators are disclosed on page 203 of the Odian book “Principle of Polymerization (Wiley, 1981)", which can be referred to.
  • ascorbic acid and potassium persulfate are used as the thermal polymerization initiator.
  • photo polymerization initiator examples include, for example, benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketal ( One or more compounds selected from the group consisting of Benzyl Dimethyl Ketal, acyl phosphine and alpha-aminoketone may be used.
  • 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.
  • More various photopolymerization initiators are disclosed on page 115 of Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007)", which can be referred to.
  • the polymerization initiator may be added in a concentration of about 0.001 to 1% by weight relative to the monomer composition. That is, when the concentration of the polymerization initiator is too low, the polymerization rate may be slow, and residual monomers in the final product may be extracted in large quantities, which is not preferable. Conversely, when the concentration of the polymerization initiator is higher than the above range, the polymer chains forming the network are shortened, and thus the content of the water-soluble component is increased and the pressure absorption capacity is lowered, so that the physical properties of the resin may be deteriorated, which is not preferable.
  • the polymerization step can be carried out in the presence of a blowing agent.
  • the foaming agent foams during polymerization to form pores in the hydrogel polymer to increase the surface area.
  • the foaming agent may be an inorganic foaming agent or an organic foaming agent.
  • inorganic blowing agents include sodium bicarbonate, sodium carbonate, potassium bicarbonate, potassium carbonate, calcium bicarbonate, and calcium bicarbonate. , Magnesium bicarbonate or magnesium carbonate.
  • examples of the organic blowing agent are azodicarbonamide (ADCA), dinitroso pentamethylene tetramine (DPT), p,p'-oxybisbenzenesulfonylhydrazide (p,p' -oxybisbenzenesulfonylhydrazide (OBSH), and p-toluenesulfonyl hydrazide (TSH).
  • ADCA azodicarbonamide
  • DPT dinitroso pentamethylene tetramine
  • DPT dinitroso pentamethylene tetramine
  • p,p'-oxybisbenzenesulfonylhydrazide p,p' -oxybisbenzenesulfonylhydrazide
  • TSH p-toluenesulfonyl hydrazide
  • the blowing agent is preferably used in an amount of about 0.001 to about 1% by weight based on the weight of the water-soluble ethylenically unsaturated monomer.
  • the amount of the blowing agent exceeds about 1% by weight, the pores become too large, the gel strength of the super absorbent polymer falls and the density becomes small, which may cause problems in distribution and storage.
  • the monomer composition may further include additives such as a surfactant, a thickener, a plasticizer, a storage stabilizer, and an antioxidant, if necessary.
  • additives such as a surfactant, a thickener, a plasticizer, a storage stabilizer, and an antioxidant, if necessary.
  • such a monomer composition may be prepared in the form of a solution in which a raw material such as the above-described monomer is dissolved in a solvent.
  • a raw material such as the above-described monomer is dissolved in a solvent.
  • a usable solvent any material that can dissolve the aforementioned raw materials can be used without limitation of its configuration.
  • the solvent includes 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, N,N-dimethylacetamide, or mixtures thereof, and the like can be used.
  • the formation of a hydrogel polymer through polymerization of the monomer composition may be performed by a conventional polymerization method, and the process is not particularly limited.
  • the polymerization method is largely divided into thermal polymerization and photo polymerization according to the type of polymerization energy source.
  • the thermal polymerization is performed, the polymerization method may be performed in a reactor having a stirring axis such as a kneader, and photo polymerization In the case of proceeding, it may proceed in a reactor equipped with a movable conveyor belt.
  • a hydrogel polymer may be obtained by introducing the monomer composition into a reactor such as a kneader equipped with a stirring shaft, and supplying hot air to it or heating the reactor to thermally polymerize it.
  • a reactor such as a kneader equipped with a stirring shaft
  • the hydrogel polymer discharged to the reactor outlet may be obtained as particles of several millimeters to several centimeters.
  • the resulting hydrogel polymer can be obtained in various forms depending on the concentration and injection speed of the monomer composition to be injected, and a hydrogel polymer having a particle diameter of 2 to 50 mm (average weight) is usually obtained.
  • a hydrogel polymer in the form of a sheet may be obtained.
  • the thickness of the sheet may vary depending on the concentration and injection rate of the monomer composition to be injected. In order to ensure the production speed and the like while allowing the entire sheet to be evenly polymerized, it is usually adjusted to a thickness of 0.5 to 5 cm. desirable.
  • the normal water content of the hydrogel polymer obtained in this way may be about 40 to about 80% by weight.
  • water content in the present specification refers to a value obtained by subtracting the weight of the polymer in the dry state from the weight of the water-containing gel polymer as the amount of moisture occupied with respect to the total weight of the hydrogel polymer. Specifically, it is defined as a calculated value by measuring a 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 about 180°C.
  • the total drying time is set to about 20 minutes, including about 5 minutes in the temperature rising step, to measure the water content.
  • the drying step is a step of drying the hydrogel polymer prepared in the polymerization step to make a dry polymer.
  • the hydrogel polymer having a water content of about 40 to about 80% by weight is pulverized in a hydrogel state, as described above, to improve drying efficiency.
  • a gel grinding or gel disintegration step, which promotes improvement, may optionally be performed.
  • Such gel grinding, or gel disintegration is a vertical pulverizer, a turbo cutter, a turbo grinder, a rotary cutter mill, and a cutter mill.
  • Disc mill, shred crusher, crusher, chopper, and disc cutter may be performed using any one selected from the group of grinding machines.
  • the gel grinding step may be performed such that the particle diameter of the hydrogel polymer after grinding is about 2 mm to about 10 mm. It is not technically easy to adjust the particle size after gel grinding to be small due to the high water content of the hydrogel polymer, and when the particle diameter is too small after pulverization, a phenomenon that the pulverized hydrogel polymers aggregate again may appear. On the other hand, if the particle size is too large after gel grinding, the effect of increasing the efficiency of the subsequent drying step may be insignificant.
  • the hydrous gel-like polymer that has been subjected to gel grinding as described above or has not undergone a gel grinding step is introduced into a drying step and dried.
  • the drying temperature of the drying step may be about 50 to about 250 °C. If the drying temperature is too low, a drying time may be too long, and a problem of deterioration in physical properties of the superabsorbent polymer to be formed may occur. When the drying temperature is too high, only the polymer surface is dried due to a fast drying rate, which is achieved later. Fine powder may be generated in the pulverization process, and there is a fear that the physical properties of the superabsorbent polymer finally formed may be deteriorated.
  • the drying may be carried out at a temperature of about 150 to about 200 °C, more preferably at a temperature of about 160 to about 190 °C.
  • process efficiency and the like may be considered, and may be performed for about 20 minutes to about 15 hours, but the present invention is not necessarily limited thereto.
  • the device used in the drying may be selected and used without limitation of its configuration.
  • the drying step may be performed by a method such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation.
  • the water content of the polymer after the drying step, that is, the dry polymer may be from about 0.05 to about 10% by weight.
  • the crushing step is a step of pulverizing the dried polymer dried in the drying step to prepare a base resin in the form of particles, and may be divided into a first crushing step and a second crushing step.
  • the present invention in order to reduce the generation of fine powder, it is characterized in that, among the particles pulverized through the first pulverization, only abnormal particles having a particle diameter equal to or larger than a target particle diameter are again pulverized.
  • the first grinding may correspond to coarse grinding
  • the second grinding may correspond to fine grinding
  • both the first pulverization and the second pulverization may correspond to a fine grinding process.
  • both the first and second pulverization correspond to fine grinding
  • it may be further performed by further comprising a separate coarse pulverization process prior to the first pulverization.
  • the particles of the pulverized base resin after co-grinding may be preferable in terms of the efficiency of crushing in a particle size range of about 800 ⁇ m to about 5000 ⁇ m.
  • the present invention can be carried out using a continuous roll mill and classifier.
  • the grinding step may be performed using a single roll mill, or a multi-stage roll mill, and a classifier.
  • the classifier is provided with a classifier having the same size as the target particle size, and performs the primary classification with'normal particles' having a particle size larger than the target particle size and'normal particles' having a particle diameter less than the target particle size. do.
  • the target target particle size as described above, in the second particle classification step of the second pulverization step, means a particle diameter that is a reference for classification for separating normal particles and abnormal particles, from about 200 to about 850 It can be selected in the range of ⁇ m. Preferably, it may be selected from a range of about 200 ⁇ m or more, or about 300 ⁇ m or more, or about 420 ⁇ m or more, about 850 ⁇ m or less, or about 800 ⁇ m or less, or about 750 ⁇ m or less, or about 700 ⁇ m or less.
  • the pulverization conditions in each pulverization step can be relaxed and proceed. Accordingly, it is possible to increase the'ratio of particles having a relatively large particle size', which is a target in each grinding step, and as a result, the generation of fine powder in each grinding step can be further reduced.
  • the proportion of abnormal particles having a particle diameter equal to or greater than the target target particle diameter is about 60 wt% or more, or about 80 wt%, relative to the total weight of the whole crushed particles
  • the pulverization conditions of the first pulverization may be adjusted to be greater than or equal to or greater than about 90 wt%, less than or equal to about 99 wt%, or less than about 95 wt%.
  • the pulverization conditions of the first pulverization can be adjusted to be 5.0 wt% or less, or about 1.0 wt% or less.
  • the fine particles having a particle diameter of less than about 150 ⁇ m or less than about 180 ⁇ m among the particles prepared in the grinding step may be discarded or reassembled by adding water to circulate to the drying step.
  • the second pulverization step is a step of classifying and pulverizing the first pulverized particles in the pulverization step. In order to distinguish it from the first pulverization step described above, it is referred to as'secondary pulverization' in this specification. .
  • the second pulverization may refer to the first pulverization step of pulverization.
  • the first pulverization is the first pulverization step of the fine grinding
  • the second pulverization means the second pulverization stage of the fine grinding.
  • the second grinding process is performed at least once, or at least twice, or 2 to 5 times, or 3 to 4 times, and by using the grinder and classifier together in each grinding step, the target particle size
  • the smaller particles can be prevented from being further crushed together with particles larger than the target particle size, thereby reducing the generation of fines.
  • the first pulverization corresponds to coarse pulverization
  • the first and second angular crushing steps of the present invention use a continuous multi-stage roll mill, or a continuous single roll mill, wherein the sequential roll mill is the bottom of the crushing stage or the last stage.
  • the sequential roll mill is the bottom of the crushing stage or the last stage.
  • the present invention can be carried out by using the multi-stage roll as described above, but the gap width of each stage of the roll forming the multi-stage roll is different from the top to the bottom.
  • the second grinding it is preferable to use a device having a narrower roll gap width than the first grinding, and the second grinding is repeated two or more times. In the case, it is preferable to use a narrower roll gap width as the order is added.
  • the gap width may refer to the distance between the rolls in the configuration of each stage constituting the multi-stage roll.
  • stepwise narrowing the distance between the roll mills to increase the degree of crushing, normal particles among the crushed products crushed in each step do not proceed to further grinding, only additional grinding By putting in the step, excessive pulverization can be reduced, and accordingly, the amount of fine powder can be reduced.
  • the roll used for grinding may consist of two.
  • the gap width refers to the distance between two rolls. The narrower the gap width of the roll, the smaller the size distribution of the pulverized particles.
  • the gap width of the upper roll mill can be fixedly positioned to be, for example, about 4.0 to about 5.0 mm, and the gap width of the lower roll mill is, for example, about 1.5 mm It can be made as follows. That is, it is preferable to perform grinding and classification while gradually reducing the width of the roll gap by the second number of times of grinding. For example, it is preferable to adjust the gap width of the single roll mill forming the bottom while narrowing the gap width by about 0.3 mm to about 0.6 mm, depending on the number of times the second milling is performed.
  • a re-classification step may be added to classify the particles into particles having a particle diameter of about 150 to about 850 ⁇ m again and smaller particles, among which about 150 to Particles having a particle diameter of about 850 ⁇ m can be used as the final product.
  • it may include a step of separating particles having a particle diameter of less than 150 ⁇ m, that is, fine particles or fine powder, re-assembled by adding water, and circulating to the drying step.
  • the reassembly method may be performed according to a method well known in the art, but is not limited to the method.
  • the surface of the single roll mill may exhibit a corrugated roll surface, but is not limited thereto.
  • the rotational speed of a single roll mill constituting each stage may be 2 m/s to 15 m/s.
  • the present invention may include a step of crosslinking the surface of the prepared particles as necessary.
  • the present invention can use the normal particles obtained through the above-described method as a base resin powder. Therefore, the present invention may further include forming a surface crosslinking layer by further crosslinking the surface of the base resin powder in the presence of a surface crosslinking agent.
  • the step of heat-treating the prepared particles may further include surface crosslinking.
  • the surface crosslinking solution may include any one or more surface crosslinking agents selected from the group consisting of compounds having two or more epoxy rings, and compounds having two or more hydroxys.
  • the surface crosslinking solution includes both compounds having two or more epoxy rings and compounds having two or more hydroxys.
  • the surface crosslinking solution contains a compound having two or more epoxy rings and a compound having two or more hydroxy groups in a ratio of 1:1.1 to 1:5.
  • Examples of the compound having two or more epoxy rings ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl Diyl ether, 1,4-butanediol diglycidyl ether, 1,4-cyclohexanedimethanol diglycidyl ether, hexahydrophthalic anhydride diglycidyl ether, neopentyl glycol diglycidyl ether, And at least one compound selected from the group consisting of bisphenol a diglycidyl ether and N,N-diglycidyl aniline.
  • ethylene glycol diglycidyl ether is used.
  • propylene glycol is used.
  • the surface crosslinking agent is preferably used in an amount of 1 part by weight or less based on 100 parts by weight of the base resin.
  • the amount of the surface crosslinking agent used means the total amount of the surface crosslinking agent when two or more are used.
  • the surface crosslinking agent is preferably used in an amount of 0.01 parts by weight or more, 0.02 parts by weight or more, 0.03 parts by weight or more, 0.04 parts by weight or more, or 0.05 parts by weight or more based on 100 parts by weight of the base resin.
  • the surface crosslinking solution is 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, It may further include one or more solvents selected from the group consisting of N-dimethylacetamide. Preferably, water is included. The solvent may be used in 0.5 to 10 parts by weight relative to 100 parts by weight of the base resin powder.
  • the surface crosslinking solution may further include aluminum sulfate.
  • the aluminum sulfate may be included in 0.02 to 0.3 parts by weight based on 100 parts by weight of the base resin powder.
  • the surface crosslinking solution may include an inorganic filler.
  • 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.
  • the surface crosslinking solution may further include a thickener.
  • a thickener 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.
  • 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 Can.
  • specific examples of the hydroxy-containing polymer include polyethylene glycol and polyvinyl alcohol.
  • the surface crosslinking solution and the base resin are mixed in a reaction tank, a method of spraying a surface crosslinking solution on the base resin, and the surface resin and the surface crosslinking in a continuously operated mixer.
  • a method of continuously supplying and mixing the liquid may be used.
  • the surface crosslinking may be performed under a temperature of 100 to 250°C, and may be continuously performed after the drying and pulverizing steps proceeding at a relatively high temperature. At this time.
  • the surface crosslinking reaction may be performed for 1 to 120 minutes, or 1 to 100 minutes, or 10 to 60 minutes. That is, while inducing a minimum amount of the surface crosslinking reaction, the polymer particles may be damaged during excessive reaction to prevent the physical properties from being deteriorated, and thus the conditions of the surface crosslinking reaction may be performed.
  • the input unit 100 to which the dry polymer is introduced A crushing unit 200 for pulverizing the introduced dry polymer; And an outlet portion 300 for discharging the pulverized dry polymer particles;
  • the crushing unit 200 includes a first crushing unit 210 and a second crushing unit 220 for pulverizing the dried polymer, and the second crushing unit 220 is the first An abnormal particle classifying portion 221 for classifying the dried polymer pulverized in the primary crushing unit 210 into'abnormal particles' having a particle diameter equal to or larger than the target particle diameter and'normal particles' having a particle diameter smaller than the target particle diameter; And an abnormal particle pulverization portion 222 that collects only the “abnormal particles” and crushes them again.
  • FIG. 1 shows a super absorbent fabrication apparatus according to an embodiment of the present invention.
  • the input unit 100 is introduced to the dry polymer;
  • the crushing unit 200 includes a first crushing unit 210 and a second crushing unit 220 for pulverizing the dried polymer, and the second crushing unit 220 is the first An abnormal particle classifying portion 221 for classifying the dried polymer pulverized in the primary crushing unit 210 into'abnormal particles' having a particle diameter equal to or larger than the target particle diameter and'normal particles' having a particle diameter smaller than the target particle diameter; And it can be seen that it comprises an abnormal particle crushing portion 222, which collects only the'abnormal particles' and crushes it again.
  • the second pulverization unit includes one or more or two or more.
  • the crushing unit includes a roll mill, and the roll gap width in the roll mill forming each stage included in the first crushing unit and the second crushing unit has a structure that becomes narrower from top to bottom. It may be preferable, and if the second pulverization part is included in two or more, it may also be desirable to have a structure in which the width of the roll gap in the roll mill forming each stage becomes narrower as the order is added.
  • abnormal particle classification portion may be located at the bottom of each stage single roll mill.
  • the base resin dried through the input unit 100 is introduced, and is moved to the first crushing unit 210.
  • the second pulverization unit is an abnormality in which the dry polymer pulverized in the first pulverization unit 210 is classified into'abnormal particles' having a particle diameter equal to or larger than a target particle diameter and'normal particles' having a particle diameter smaller than a target particle diameter. It includes a particle classification portion 221, and such a classification portion may be specifically configured in the form of a classification body.
  • the abnormal particle classification part 221 In the case of abnormal particles, through the abnormal particle classification part 221, only'abnormal particles' are collected and crushed again, to the abnormal particle crushing part 222 It is injected, and in the case of normal particles, it passes directly through the particle classification portion 221 in the form of a sieve, and is moved to the discharge portion.
  • the abnormal particles introduced into the abnormal particle crushing portion 222 are again crushed by a roll mill.
  • the base resin particles pulverized again in the abnormal particle crushing portion 222 again pass through the abnormal particle classification portion 221, in which, in the case of abnormal particles, only ⁇ abnormal particles'' are collected and crushed again, 222), and in the case of normal particles, may pass directly through the particle classification portion 221 in the form of a sieve, and may be moved to the discharge portion.
  • the second crushing unit may include one or more.
  • the present invention in the process of forming a hydrogel polymer to form a super absorbent polymer, and then classifying it after drying, pulverize large particles of a certain size or more, and filter particles of a certain size or less through classification after each step to filter the particles It can block crushing and minimize the formation of particles of 150 ⁇ m or less.
  • the present invention can be repeated several times to change the particle size of the final superabsorbent polymer product by varying the particle size of the classification after each step of pulverization and at the time of classification.
  • the superabsorbent polymer production method according to the present invention while implementing a narrow particle size distribution in the grinding process of the dried polymer, reducing the amount of fine powder, it is possible to reduce the load of the fine powder reassembly, drying, grinding and classification process.
  • FIG. 1 schematically shows an apparatus for manufacturing a super absorbent polymer according to an embodiment of the present invention.
  • the monomer composition was supplied at a speed of 500 to 2000 mL/min on a rotating conveyor belt in which a belt of 10 cm in width and 2 m in length continuously moves at a speed of 50 cm/min. Then, simultaneously with the supply of the monomer composition, irradiated with ultraviolet light having an intensity of 10 mW/cm 2 , a polymerization reaction was performed for 60 seconds to prepare a hydrogel polymer.
  • the hydrogel polymer having the polymerization reaction completed is cut to a size of 0.1 to 1.0 cm ⁇ 0.1 to 1.0 cm through a screw-type extruder (meat chopper: hole size 16 mm) mounted inside the cylindrical grinder, and an air-flow oven is used. And dried at 195°C for 40 minutes.
  • Grinding stage primary grinding (including coarse grinding) and classification stage
  • the dried polymer was ground using a two-stage roll mill (GRAN-U-LIZERTM, MPE). After grinding, the grinding conditions were adjusted so that the particle ratio of 600 ⁇ m or more became 90% or more.
  • the pulverized polymer particles were classified using a classifying sieve, and then separated into particles of 600 ⁇ m or more and particles of less than 600 ⁇ m.
  • the standards of classifiers are classified using 4750 ⁇ m, 3350 ⁇ m, 2000 ⁇ m, 850 ⁇ m, 710 ⁇ m, 600 ⁇ m, 425 ⁇ m, 300 ⁇ m, 180 ⁇ m, and 150 ⁇ m pan based on ASTM standards. After pulverization, the particle size of the particles was measured.
  • the roll gap width of the top roll was about 5.0 mm, and the roll gap width of the bottom roll was about 4.0 mm.
  • particles having a particle diameter of 600 ⁇ m or more among the particles that were first coarsely pulverized in the above step were pulverized using a single roll mill.
  • the pulverized particles were separated into particles having a particle diameter of 600 ⁇ m or more (ie, abnormal particles) and particles having a particle diameter of less than 600 ⁇ m (ie, normal particles) using a classifier disposed at the rear end.
  • the normal particles were discharged as they were, and only the abnormal particles were selected, and then put again in a single roll mill to perform grinding.
  • the pulverized particles were separated into abnormal particles having a particle diameter of 600 ⁇ m or more and normal particles having a particle diameter of less than 600 ⁇ m through a classifier placed at the rear end of the roll mill.
  • the normal particles were discharged as they were, and only the abnormal particles were selected, and then again put into a single roll mill to perform grinding.
  • the crushing was repeated three times and the classification process was repeated two times.
  • the roll gap width of the single roll mill was 1.0 mm, 0.4 mm, and again 0.19 mm. .
  • the particles collected in the above are classified by a standard network of ASTM standard by a conventional method, to separate coarse powder having a particle diameter of 850 ⁇ m or more and fine powder having a particle size of 150 ⁇ m or less, and 150 ⁇ m or more and 850 as particles for product production. Only particles smaller than ⁇ m were selected.
  • Example 1 in the fine grinding and classifying step, the target particle size was set to 425 ⁇ m, not 600 ⁇ m, and the roll gap width of the single roll mill was 1.0 mm, 0.4 mm, and again 0.17 mm in three pulverization processes. , It proceeded in the same manner as in Example 1, except that the width of the roll gap was narrowed according to the number of times of each progress.
  • Example 1 in the pulverizing and classifying step, two pulverizing and one classifying processes were repeated, and the roll gap width of a single roll mill was 0.6 mm and 0.16 mm in each of the two pulverizing processes. Accordingly, the procedure was the same as in Example 1, except that the width of the roll gap was narrowed.
  • Example 1 in the pulverizing and classifying step, four pulverizing and three classifying processes were repeated, and the roll gap width of a single roll mill in two pulverizing processes was 1.5 mm, 0.8 mm, 0.4 mm, and 0.18 mm. Furnace, the process was performed in the same manner as in Example 1, except that the width of the roll gap was narrowed according to the number of times of each progress.
  • Example 1 without performing a separate classification process after pulverization, all the pulverized particles are introduced into a subsequent roll mill, and in three fine grinding processes, the roll gap width of a single roll mill is 1.0 mm, 0.4 mm, 0.16. In mm, the procedure was the same as in Example 1, except that the width of the roll gap was narrowed according to the number of times of each progress.
  • a mesh sieve of 850 ⁇ m, 710 ⁇ m, 600 ⁇ m, 425 ⁇ m, 300 ⁇ m, 180 ⁇ m, and 150 ⁇ m Pan of ASTM standard was used, and vibration was applied for 10 minutes at an amplitude of 1.5 mm/'g' to classify particles. After that, the weight of the particles on the top of each sieve was measured to obtain the particle size.
  • Example 1 Example 2
  • Example 3 Example 4 20 mesh phase (>850 ⁇ m) 0.1 0.0 0.1 0.1 0.1 30 mesh phase (600 ⁇ m or more but less than 850 ⁇ m) 2.5 3.4 3.2 3.2 3.0 40 mesh phase (425 ⁇ m or more and less than 600 ⁇ m) 24.4 36.9 24.6 31.8 36.5 50 mesh phase (300 ⁇ m or more but less than 425 ⁇ m) 25.2 21.6 28.9 23.1 22.5 100 mesh phase (more than 150 ⁇ m less than 300 ⁇ m) 22.3 18.2 22.0 19.9 18.1 100 mesh pass (less than 150 ⁇ m) 25.5 19.9 21.2 21.9 19.8 Differentiation rate* 34.2 24.8 26.9 28.0 24.6 * A value obtained by dividing the weight (g) of particles having a particle diameter of less than 150 ⁇ m by the weight (g) of particles (normal particles) having a particle diameter of 150 ⁇ m or more to less than 850 ⁇ m.
  • particles having a size of 600 ⁇ m or more and less than 850 ⁇ m are about 2.5 wt%
  • particles having a size of 425 ⁇ m or more and less than 600 ⁇ m are about 24.4 wt%
  • 300 ⁇ m Particles having a size of more than 425 ⁇ m were about 25.2% by weight
  • particles having a size of 150 ⁇ m or more and less than 300 ⁇ m constituted 22.4% by weight The ratio of fine powder generation to normal particles having a particle diameter of 150 ⁇ m or more and less than 850 ⁇ m was about 34.3% by weight.
  • the term fine powder refers to particles having a size of less than 150 ⁇ m.
  • particles having a size of 600 ⁇ m or more and less than 850 ⁇ m are about 3.4% by weight
  • particles having a size of 425 ⁇ m or more and less than 600 ⁇ m are about 36.9% by weight
  • 300 ⁇ m or more and having a size of less than 425 ⁇ m The particles were about 21.5% by weight, and particles having a size of 150 ⁇ m or more and less than 300 ⁇ m were about 18.2% by weight.
  • Example 1 when compared with Comparative Example 1, the proportion of particles having a size of 425 ⁇ m or more and less than 600 ⁇ m was increased, and a ratio of particles having a size of 150 ⁇ m or more and less than 425 ⁇ m was decreased.
  • the ratio of fine particles to the normal particles was about 24.9% by weight, showing an effect of decreasing by about 27% compared to Comparative Example 1. This is thought to be caused by separating particles having a particle diameter of less than about 600 ⁇ m through classification in the fine grinding process and blocking them from being added to a further grinding process.
  • particles having a size of 600 ⁇ m or more and less than 850 ⁇ m are about 3.2 wt%
  • particles having a size of 425 ⁇ m or more and less than 600 ⁇ m are about 24.6 wt%
  • particles having a size of 300 ⁇ m or more and less than 425 ⁇ m Was about 28.9% by weight
  • particles having a size of 150 ⁇ m or more and less than 300 ⁇ m were about 22.0%.
  • the ratio of fine powder generation to normal particles was about 27% by weight, showing an effect of about 21% reduction compared to Comparative Example 1.
  • the particle size of the pulverized particles can be adjusted by varying the classification criteria of the classified particles in the fine grinding process, that is, the target particle size.
  • the ratio of fine particles to the normal particles was about 28.2% by weight and about 24.8% by weight, respectively.
  • the number of times the pulverization and classification was repeatedly performed in the pulverization process it was confirmed that the amount of pulverization was decreased and the reduction rate according to the number of times was decreased.
  • Example 1 Example 2
  • Example 3 Example 4 Apparent density (g/ml) 0.50 0.48 0.47 0.50 0.48 Vortex (sec) 23.7 24.1 23.0 23.8 24.7
  • the embodiment of the present invention can improve productivity by reducing the generation of fine powders while realizing existing physical properties.

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Abstract

La présente invention concerne un procédé de préparation d'un polymère superabsorbant, selon la présente invention, dans lequel: dans un processus de broyage et de classification, après la formation et le séchage d'un polymère d'hydrogel, la quantité de fines générées qui sont de 150 µm ou moins peut être réduite au minimum par le blocage de particules ayant une taille spécifique ou plus petites pour les empêcher d'être incluses dans le broyage; la taille de particule d'un produit final peut être facilement ajustée en fonction d'un réglage de diamètre de particule cible d'un classificateur; et un polymère superabsorbant présentant des propriétés physiques égales ou supérieures à celles des polymères superabsorbants classiques peut être préparé.
PCT/KR2020/000761 2019-01-16 2020-01-16 Procédé de préparation d'un polymère superabsorbant WO2020149651A1 (fr)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010522779A (ja) * 2007-03-26 2010-07-08 株式会社日本触媒 粒子状吸水性樹脂の分級方法
WO2011034146A1 (fr) * 2009-09-16 2011-03-24 株式会社日本触媒 Procédé de production d'une poudre de résine absorbant l'eau
KR20110131131A (ko) * 2010-05-28 2011-12-06 주식회사 엘지화학 고흡수성 수지용 분쇄장치 및 이를 이용한 고흡수성 수지의 제조 방법
JP2015048386A (ja) * 2013-08-30 2015-03-16 株式会社日本触媒 吸水性樹脂の微粉砕方法及び耐塩性に優れた吸水性樹脂
KR20150090067A (ko) * 2012-11-27 2015-08-05 가부시키가이샤 닛폰 쇼쿠바이 폴리아크릴산(염)계 흡수성 수지의 제조 방법

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010522779A (ja) * 2007-03-26 2010-07-08 株式会社日本触媒 粒子状吸水性樹脂の分級方法
WO2011034146A1 (fr) * 2009-09-16 2011-03-24 株式会社日本触媒 Procédé de production d'une poudre de résine absorbant l'eau
KR20110131131A (ko) * 2010-05-28 2011-12-06 주식회사 엘지화학 고흡수성 수지용 분쇄장치 및 이를 이용한 고흡수성 수지의 제조 방법
KR20150090067A (ko) * 2012-11-27 2015-08-05 가부시키가이샤 닛폰 쇼쿠바이 폴리아크릴산(염)계 흡수성 수지의 제조 방법
JP2015048386A (ja) * 2013-08-30 2015-03-16 株式会社日本触媒 吸水性樹脂の微粉砕方法及び耐塩性に優れた吸水性樹脂

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