WO2021091240A1 - 고흡수성 수지의 제조 방법 - Google Patents
고흡수성 수지의 제조 방법 Download PDFInfo
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- WO2021091240A1 WO2021091240A1 PCT/KR2020/015363 KR2020015363W WO2021091240A1 WO 2021091240 A1 WO2021091240 A1 WO 2021091240A1 KR 2020015363 W KR2020015363 W KR 2020015363W WO 2021091240 A1 WO2021091240 A1 WO 2021091240A1
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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
- C08F6/00—Post-polymerisation treatments
- C08F6/008—Treatment of solid polymer wetted by water or organic solvents, e.g. coagulum, filter cakes
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/24—Crosslinking, e.g. vulcanising, of macromolecules
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/01—Use of inorganic substances as compounding ingredients characterized by their specific function
- C08K3/013—Fillers, pigments or reinforcing additives
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/05—Alcohols; Metal alcoholates
- C08K5/053—Polyhydroxylic alcohols
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K5/00—Use of organic ingredients
- C08K5/04—Oxygen-containing compounds
- C08K5/10—Esters; Ether-esters
- C08K5/109—Esters; Ether-esters of carbonic acid, e.g. R-O-C(=O)-O-R
Definitions
- the present invention relates to a method for producing a super absorbent polymer. More specifically, the water content of the super absorbent polymer is improved to prevent the change in surface characteristics due to external changes, and the amount of fine powder is reduced to improve processability in the manufacture of articles using the super absorbent polymer. It relates to a manufacturing method.
- Super Absorbent Polymer is a synthetic polymer material that has the ability to absorb moisture of 500 to 1,000 times its own weight, and each developer has a SAM (Super Absorbency Material), AGM (Absorbent Gel). Material) and so on. Since the above-described superabsorbent resin has begun to be put into practical use as a sanitary tool, nowadays, in addition to hygiene products such as paper diapers for children, soil repair agents for horticultural use, water resistant materials for civil engineering and construction, sheets for seedlings, freshness maintenance agents in the food distribution field, and It is widely used as a material for poultice.
- SAM Super Absorbency Material
- AGM Absorbent Gel
- a thermal polymerization method in which polymerization gel is polymerized while breaking and cooling the polymerized gel in a kneader equipped with several shafts, and a photopolymerization method in which polymerization and drying are simultaneously performed by irradiating a high-concentration aqueous solution with ultraviolet rays on a belt. Etc. are known.
- the hydrogel polymer obtained through the polymerization reaction as described above is generally pulverized through a drying process and then commercially available as a powder product.
- the surface crosslinking reaction is carried out by spraying a surface crosslinking solution in which a crosslinking agent is added to water, stirring the surface of the superabsorbent polymer, and applying heat to react.
- the surface crosslinking reaction by heating is usually carried out at a high temperature of 140° C. or higher, most of the moisture contained in the super absorbent polymer evaporates, and as a result, the moisture content of the finally produced super absorbent polymer is greatly reduced.
- the superabsorbent polymer having a low moisture content is likely to cause surface damage due to friction between particles occurring during transport and storage, which ultimately leads to deterioration in physical properties of the superabsorbent polymer.
- the amount of fine powder is increased during the commercialization process using the super absorbent polymer having a low moisture content, resulting in a decrease in process stability and productivity, resulting in a decrease in product quality.
- a direct injection method through a line and an injection method using a spray nozzle are mainly used.
- a direct injection method through a line there is a problem in that the size of droplets is large, resulting in a mixture of large particles having a high moisture content and general particles having a low moisture content.
- the moisture content can be evenly increased, but flow occurs due to the small droplet size, and contamination of the device and foreign matter are the cause of the occurrence.
- An object of the present invention is to provide a method of manufacturing a super absorbent polymer and a super absorbent polymer prepared according to the method of manufacturing a super absorbent polymer, which can improve processability such as preventing clogging of a bag filter and preventing caking when manufacturing an article using a super absorbent polymer.
- Forming a hydrogel polymer by performing thermal polymerization or photopolymerization on a monomer composition comprising a water-soluble ethylenically unsaturated monomer and a polymerization initiator;
- Equation 1 Re droplet is the Reynolds number of a droplet, and Re air is the Reynolds number of air.
- a super absorbent polymer of the present invention According to the method of manufacturing a super absorbent polymer of the present invention, it is possible to manufacture a super absorbent polymer having an improved water content and no fear of a change in surface properties due to external changes. In addition, since the amount of fine powder generated in the super absorbent polymer is reduced, it is possible to improve processability such as preventing clogging of a bag filter and preventing caking when manufacturing an absorbent article using the same.
- the droplet size is uniformly and easily controlled, thereby increasing the moisture content of the super absorbent polymer to prevent changes in surface characteristics due to external changes.
- the amount of fine powder is reduced, it is possible to improve processability when manufacturing an article using a super absorbent polymer.
- step 1 Forming a hydrogel polymer by performing thermal polymerization or photopolymerization on a monomer composition comprising a water-soluble ethylenically unsaturated monomer and a polymerization initiator (step 1);
- step 2 Drying and pulverizing the hydrogel polymer to prepare a base resin powder (step 2);
- step 3 Adding a surface crosslinking agent to the base resin powder and performing a surface crosslinking reaction to prepare a surface crosslinked base resin powder (step 3); And
- the scattering index of the droplet generated during the pulse spraying according to Equation 1 below is 5 to 10.
- Equation 1 Re droplet is the Reynolds number of a droplet, and Re air is the Reynolds number of air.
- Conditions during the pulse spraying affect the size of the droplets, and through control of these conditions, the size of the generated droplets can be determined with high absorbency. It can be optimized to a range that can minimize the water content improvement of the resin and the generation of fine particles or coarse particles.
- the optimum size of the droplet is defined as the scattering index using the Reynolds number of the droplet.
- the droplet generated during the pulse spraying has a scattering index of 5 or more, or 6 or more, or 7 or more, or 7.5 or more, or 7.8 or more, 10 or less, or 9 or less according to Equation 1 , Or less than or equal to 8.8.
- the droplet scattering index is less than 5, or exceeds 10, contamination of the reactor becomes serious due to the increase of the particle size of 300 ⁇ m or less, or the content of coarse particles with a particle size of more than 850 ⁇ m in the super absorbent polymer to be produced is large. Can increase.
- Equation 1 the Reynolds number is a term representing the ratio of the inertia force and the viscous force of a flow in fluid mechanics, and is proportional to the density of the fluid, the flow velocity, and the length of the object placed in the flow, and is proportional to the viscosity of the fluid. It is inversely proportional.
- the Reynolds numbers of the droplets and air which are fluids in the present invention, may be calculated according to Equation 2 below.
- Reynolds number [(density of fluid ⁇ average flow velocity of fluid ⁇ characteristic length of fluid)/ viscosity coefficient of fluid
- the fluid is a droplet (water) or air
- the density and viscosity of the fluid may be determined using literature values.
- the density of the droplet is 1000 kg/m 3 , which is a literature density value of water at 25° C.
- the viscosity coefficient is 10 kg/m/sec.
- the density of air is 1.12 kg/m 3 , which is a literature value at 25° C.
- the viscosity coefficient is 0.17 kg/m/sec.
- the average flow velocity of the fluid in Equation 2 can be predicted through flow analysis.
- the average flow rate of the droplets is the flow rate of the fluid introduced into the reactor, that is, the input flow rate of water (m 3 /hr), the area of the cross-sectional area in the flow direction of water, which is a fluid, of the present invention.
- water since water flows inside the orifice, it can be calculated by dividing it by the area of the orifice cut surface perpendicular to the water flow (or flow) direction.
- the average flow rate of air is the flow rate of air introduced into the reactor, that is, the sweep air flow rate (m 3 /sec), the area of the shape of the flow direction of the air in the reactor, that is, the flow direction of the air introduced into the reactor. It can be calculated by dividing by the area of the inside section of the reactor perpendicular to.
- the shape cross-section in the flow direction means a cut surface when cut in a direction perpendicular to the flow direction when the fluid flows.
- the characteristic length of the fluid means a length that affects the flow characteristics or heat transfer characteristics
- the characteristic length Lc of the fluid is the shape cross section in the flow direction
- the characteristic length of the droplet is the average diameter (SMD) of the droplet.
- SMD average diameter
- the shape cross section in the flow direction of air as it passes through the inside of the reactor corresponds to a cross section inside the reactor that is perpendicular to the flow direction of air.
- the shape cross section in the flow direction of air becomes a rectangle, and can be calculated according to Equation 3:
- Characteristic length of air [4 ⁇ (horizontal length of reactor cut surface ⁇ vertical length of reactor cut surface)] / [2 ⁇ (horizontal length of reactor cut surface + vertical length of reactor cut surface)]
- the horizontal and vertical lengths of the cut surface of the reactor are the horizontal and vertical lengths of the cut surface inside the reactor perpendicular to the flow direction of air.
- the Reynolds number of the droplet calculated according to Equation 2 may be 0.2 to 0.35, more specifically 0.2 or more, or 0.22 or more, or 0.23 or more, or 0.24 or more, 0.35 or less, or 0.3 or less, Or 0.28 or less, or 0.27 or less.
- the Reynolds number of air calculated according to Equation 2 may be 2 to 5, more specifically 2 or more, or 2.5 or more, or 2.8 or more, or 3 or more, 5 or less, or 4.5 or less, or It may be 4 or less, or 3.5 or less.
- the droplets may have an average diameter (SMD) of 400 to 600 ⁇ m, more specifically 400 ⁇ m or more, or 450 ⁇ m or more, 600 ⁇ m or less, 580 ⁇ m or less, or 550 ⁇ m or less.
- SMD average diameter
- the proportion of droplets having a diameter of 300 ⁇ m or less among the generated droplets may be 10% by weight or less, 9% by weight or less, or 8.5% by weight or less based on the total weight of the droplets.
- the content of fine droplets having a diameter in the above range, but having a diameter of 300 ⁇ m or less that may generate flow or contaminate the device is reduced, the moisture content of the super absorbent polymer can be improved, while at the same time, the degree of contamination can be minimized.
- the average diameter (SMD) of the droplets generated during the pulse spraying and the ratio of droplets having a diameter of 300 ⁇ m or less among the droplets can be measured by optical diffraction analysis or laser image analysis, and the specific measurement method is as follows: It will be described in detail in an example.
- the pulse spraying process may be performed under control conditions to satisfy the above-described droplet conditions.
- step 1 is a step of forming a hydrogel polymer by performing thermal polymerization or photopolymerization on the monomer composition.
- the monomer composition which is a raw material of the super absorbent polymer, includes a water-soluble ethylenically unsaturated monomer and a polymerization initiator.
- any monomer commonly used in the manufacture of a super absorbent polymer may be used without any particular limitation.
- any one or more monomers selected from the group consisting of anionic monomers and salts thereof, nonionic hydrophilic-containing monomers, amino group-containing unsaturated monomers, and quaternary products thereof may be used.
- (meth)acrylic acid maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2-(meth)acryloylpropanesulfonic acid or 2- Anionic monomers of (meth)acrylamide-2-methyl propane sulfonic acid and salts thereof; (Meth)acrylamide, N-substituted (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate or polyethylene glycol ( Nonionic hydrophilic-containing monomers of meth)acrylate; And (N,N)-dimethylaminoethyl (meth) acrylate or (N,N)-dimethylaminopropyl (meth) acrylamide amino group-containing unsaturated monomer and a quaternary product
- acrylic acid or a salt thereof for example, an alkali metal salt such as acrylic acid or a sodium salt thereof
- an alkali metal salt such as acrylic acid or a sodium salt thereof
- the alkali metal salt of acrylic acid it can be used by neutralizing acrylic acid with a basic compound such as caustic soda (NaOH).
- the degree of neutralization may be 40 to 95 mol%, or 40 to 80 mol%, or 45 to 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 precipitates and it may be difficult for the polymerization to proceed smoothly. On the contrary, if the degree of neutralization is too low, the absorbency of the polymer is greatly reduced. It may exhibit properties such as elastic rubber that are difficult to handle.
- the concentration of the water-soluble ethylenically unsaturated monomer may be about 20 to about 60% by weight, preferably about 40 to about 50% by weight, based on the monomer composition including the raw material of the super absorbent polymer and the solvent, and polymerization It can be made into an appropriate concentration in consideration of time and reaction conditions. However, if the concentration of the monomer is too low, the yield of the superabsorbent polymer may be low and economic problems may occur. On the contrary, if the concentration is too high, a part of the monomer is precipitated or the pulverization efficiency is low when the polymerized hydrogel polymer is pulverized. In such process, problems may occur, and the physical properties of the super absorbent polymer may be deteriorated.
- the polymerization initiator used in the polymerization of the water-soluble ethylenically unsaturated monomer is not particularly limited as long as it is generally used in the production of a super absorbent polymer.
- the polymerization initiator may be a thermal polymerization initiator or a photopolymerization initiator according to UV irradiation depending on the polymerization method.
- a certain amount of heat is generated by irradiation such as UV irradiation, and a certain amount of heat is generated according to the progress of the polymerization reaction, which is an exothermic reaction, and thus a thermal polymerization initiator may be additionally included.
- the photopolymerization initiator may be used without limitation of its configuration as long as it is a compound capable of forming radicals by light such as ultraviolet rays.
- photopolymerization initiator examples include benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketone.
- Ketal examples include benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketone.
- Ketal examples include benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, and benzyl dimethyl ketone.
- Ketal acyl phosphine
- alpha-aminoketone alpha-aminoketone
- acylphosphine a commercially available lucirin TPO, that is, diphenyl(2,4,6-trimethylbenzoyl)-phosphine oxide may be used.
- the photopolymerization initiator may be included in an amount of 0.001 to 1 part by weight, or 0.005 to 0.1 part by weight based on 100 parts by weight of the monomer.
- the content of the photopolymerization initiator is less than 0.001 parts by weight, the polymerization rate may be slow, and when the content of the photopolymerization initiator exceeds 1 part by weight, the molecular weight of the superabsorbent polymer may be small and physical properties may become uneven.
- thermal polymerization initiator at least one selected from the group of initiators consisting of persulfate-based initiators, azo-based initiators, hydrogen peroxide and ascorbic acid may be used.
- persulfate-based initiators include sodium persulfate (Na 2 S 2 O 8 ), potassium persulfate (K 2 S 2 O 8 ), ammonium persulfate (Ammonium persulfate; (NH 4 ) 2 S 2 O 8 ), etc.
- examples of azo-based initiators include 2, 2-azobis-(2-amidinopropane) dihydrochloride (2, 2-azobis(2-amidinopropane) dihydrochloride), 2 , 2-azobis-(N, N-dimethylene) isobutyramidine dihydrochloride, 2-(carbamoyl azo) isobutyronitrile (2-(carbamoylazo)isobutylonitril), 2, 2-azobis[2-(2-(2-amidinopropan
- the thermal polymerization initiator may be included in an amount of 0.001 to 1 parts by weight, or 0.01 to 0.5 parts by weight based on 100 parts by weight of the monomer. If the content of the thermal polymerization initiator is less than 0.001 parts by weight, additional thermal polymerization hardly occurs, so the effect of the addition of the thermal polymerization initiator may be insignificant, and when the content of the thermal polymerization initiator exceeds 1 part by weight, the molecular weight of the super absorbent polymer is small. Physical properties may become uneven.
- the monomer composition may further include an internal crosslinking agent as a raw material of the super absorbent polymer.
- an internal crosslinking agent a crosslinking agent having at least one functional group capable of reacting with the water-soluble substituent of the water-soluble ethylenically unsaturated monomer and having at least one ethylenically unsaturated group;
- a crosslinking agent having two or more functional groups capable of reacting with a water-soluble substituent of the monomer and/or a water-soluble substituent formed by hydrolysis of the monomer may be used.
- the internal crosslinking agent include bisacrylamide having 8 to 12 carbon atoms, bismethacrylamide, poly(meth)acrylate of a polyhydric alcohol-based compound having 2 to 10 carbon atoms, or poly(meth)acrylate of a polyhydric alcohol-based compound having 2 to 10 carbon atoms.
- (Meth) allyl ether and the like, and more specifically, N, N'-methylenebis(meth)acrylate, ethyleneoxy(meth)acrylate, polyethyleneoxy(meth)acrylate, propyleneoxy(meth)acrylic Consisting of acrylate, glycerin diacrylate, glycerin triacrylate, trimethylol triacrylate, triallylamine, triaryl cyanurate, triallyl isocyanate, polyethylene glycol diacrylate, polyethylene glycol, diethylene glycol and propylene glycol One or more selected from the group may be used.
- These internal crosslinking agents are included in an amount of 0.01 to 1 parts by weight, or 0.1 to 0.5 parts by weight based on 100 parts by weight of the monomer, and can crosslink the polymerized polymer. If the content of the internal crosslinking agent is less than 0.01 parts by weight, the improvement effect according to the crosslinking is insignificant, and when the content of the internal crosslinking agent is more than 1 part by weight, the absorbency of the super absorbent polymer may be lowered.
- the monomer composition may further include one or more additives such as a thickener, a plasticizer, a storage stabilizer, and an antioxidant, if necessary.
- additives such as a thickener, a plasticizer, a storage stabilizer, and an antioxidant, if necessary.
- Raw materials such as the above-described water-soluble ethylenically unsaturated monomer, photopolymerization initiator, thermal polymerization initiator, internal crosslinking agent, and additives may be prepared in the form of a monomer composition solution dissolved in a solvent.
- the solvent that can be used at this time can be used without limitation of its composition as long as it can dissolve the above-described components, for example, water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, propylene Glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl amyl ketone, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol ethyl Ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate, and one or more selected from N, N-dimethylacetamide, and the like may be used in combination.
- the solvent may be included in a residual amount excluding the above-described components with respect to the total content of the monomer composition.
- the polymerization method is largely divided into thermal polymerization and photopolymerization depending on the polymerization energy source, and when thermal polymerization is usually performed, it can be performed in a reactor having an agitation axis such as a kneader, and when photopolymerization is performed, it is possible to move.
- thermal polymerization is usually performed, it can be performed in a reactor having an agitation axis such as a kneader, and when photopolymerization is performed, it is possible to move.
- the polymerization method described above is an example, and the present invention is not limited to the polymerization method described above.
- the hydrogel polymer obtained by thermal polymerization by supplying hot air or heating the reactor to a reactor such as a kneader equipped with a stirring shaft may be transferred to the reactor outlet according to the shape of the stirring shaft provided in the reactor.
- the discharged hydrogel polymer may be in the form of several centimeters to several millimeters.
- the size of the resulting hydrogel polymer may vary depending on the concentration and injection speed of the monomer composition to be injected, and a hydrogel polymer having a weight average particle size of 2 to 50 mm may be obtained.
- the form of the hydrogel polymer usually obtained may be a hydrogel polymer in a sheet form having the width of the belt.
- the thickness of the polymer sheet varies depending on the concentration and injection speed of the monomer composition to be injected, but it is preferable to supply the monomer composition so that a sheet-like polymer having a thickness of about 0.5 to about 5 cm can be obtained.
- the production efficiency is not preferable, and when the thickness of the polymer on the sheet exceeds 5 cm, the polymerization reaction does not occur evenly over the entire thickness due to the excessively thick thickness. I can't.
- the moisture content of the hydrogel polymer obtained by this method may be about 40 to about 80% by weight based on the total weight of the hydrogel polymer.
- water content refers to a value obtained by subtracting the weight of the dried polymer from the weight of the hydrogel polymer as the content of water occupied with respect to the total weight of the hydrogel polymer. Specifically, it is defined as a calculated value by measuring the weight loss due to evaporation of moisture in the polymer during drying by raising the temperature of the polymer through infrared heating.
- the drying condition is a method of increasing the temperature from room temperature to about 180°C and then maintaining it at 180°C. The total drying time is set to 20 minutes including 5 minutes in the temperature rising step, and the moisture content is measured.
- a coarse pulverization process of pulverizing the prepared hydrous gel polymer may be selectively performed.
- the coarse pulverization process is a process for increasing drying efficiency in a subsequent drying process and controlling the particle size of the super absorbent polymer powder to be manufactured.
- the crusher used is not limited in configuration, but specifically, a vertical cutter (Vertical pulverizer), Turbo cutter, Turbo grinder, Rotary cutter mill, Cutter mill, Disc mill, Shred crusher), a crusher, a meat chopper, and a disc cutter, but is not limited to the above-described examples.
- the coarse pulverization process may be performed, for example, so that the particle size of the hydrogel polymer is about 2 to about 10 mm. It is not technically easy to pulverize the hydrogel polymer with a particle size of less than 2 mm due to the high moisture content of the hydrogel polymer, and a phenomenon of agglomeration between the pulverized particles may occur. On the other hand, when the particle size is pulverized to exceed 10 mm, the effect of increasing the efficiency of the subsequent drying step is insignificant.
- Step 2 is a step of performing a drying and pulverizing process on the hydrogel polymer prepared in Step 1.
- the drying may be performed at a temperature of about 150 to about 250°C.
- the drying temperature is less than 150°C, the drying time may be too long and the physical properties of the finally formed super absorbent polymer may be deteriorated.
- the drying temperature exceeds 250°C, only the polymer surface is excessively dried, resulting in a subsequent pulverization process. Fine powder may be generated at, and there is a concern that the physical properties of the finally formed super absorbent polymer may be deteriorated. Therefore, preferably, the drying may be performed at a temperature of about 150 to about 200°C, more preferably about 160 to about 180°C.
- the process may be performed for about 20 to about 90 minutes in consideration of process efficiency, but is not limited thereto.
- the drying method may be selected and used without limitation of its configuration as long as it is usually used as a drying process of the hydrogel polymer.
- the drying step may be performed by a method such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation.
- the moisture content of the polymer after proceeding with such a drying step may be about 5 to about 10% by weight.
- the pulverization process may be performed so that the particle size of the polymer powder, that is, the base resin powder, is about 150 to about 850 ⁇ m.
- the grinder used to pulverize into such a particle size is specifically, a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill, or A jog mill or the like may be used, but the present invention is not limited to the above-described examples.
- a process of classifying the pulverized polymer powder according to the particle size may be further performed.
- a polymer having a particle size of about 150 to about 850 ⁇ m is classified, and only a polymer having such a particle size is used as a base resin powder to be commercialized through a surface crosslinking reaction step.
- step 3 the base resin powder obtained by drying and pulverizing in step 2 is mixed with a surface crosslinking agent and heated to perform a surface crosslinking reaction.
- Surface crosslinking is a step of increasing the crosslinking density near the surface of the base resin powder in relation to the crosslinking density inside the particles.
- the surface crosslinking agent is applied to the surface of the base resin powder.
- this reaction occurs on the surface of the base resin powder, which improves the crosslinkability on the surface of the particles without substantially affecting the inside of the particles. Therefore, the surface crosslinked base resin powder has a higher degree of crosslinking near the surface than at the inside.
- the surface crosslinking agent is not limited in its configuration as long as it is a compound capable of reacting with a functional group of the polymer.
- a polyhydric alcohol-based compound as the surface crosslinking agent; Epoxy compounds; Polyamine compounds; Haloepoxy compounds; Condensation products of haloepoxy compounds; Oxazoline compounds; Mono-, di- or polyoxazolidinone compounds; Cyclic urea compounds; Polyvalent metal salts; And one or more selected from the group consisting of alkylene carbonate-based compounds may be used.
- examples of the polyhydric alcohol-based compound include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, Selected from the group consisting of 2-methyl-1,3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, tripropylene glycol and glycerol One or more of these can be used.
- ethylene glycol diglycidyl ether and glycidol may be used as the epoxy compound, and as polyamine compounds, ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, pentaethylenehexamine , Polyethyleneimine and polyamide polyamine may be used at least one selected from the group consisting of.
- haloepoxy compound epichlorohydrin, epibromohydrin, and ⁇ -methylepichlorohydrin may be used.
- mono-, di-, or polyoxazolidinone compound for example, 2-oxazolidinone may be used.
- an alkylene carbonate having 2 to 6 carbon atoms such as ethylene carbonate or propylene carbonate may be used. Each of these may be used alone, or two or more types of alkylene carbonates having different carbon atoms may be used in combination.
- a metal-containing sulfate salt such as aluminum or a carboxylate salt may be used, and more specifically, aluminum sulfate, aluminum carboxylate, or a mixture thereof may be used. Among these, aluminum sulfate may be more preferably used.
- a mixture of a polyhydric alcohol-based compound, an alkylene carbonate-based compound, and a polyvalent metal salt More specifically, 0.01 to 2 parts by weight, or 0.1 to 1 parts by weight of a polyhydric alcohol-based compound based on 100 parts by weight of the base resin powder; 0.01 to 3 parts by weight of an alkylene carbonate-based compound, or 0.05 to 2 parts by weight, or 0.1 to 1 part by weight; And 0.1 to 1 parts by weight, or 0.2 to 0.5 parts by weight of a polyvalent metal salt; may be mixed and used.
- the surface crosslinking agent containing the polyhydric alcohol-based compound, the alkylene carbonate-based compound, and the polyvalent metal salt, as a polyvalent metal salt is 0.1 to 1 part by weight, or 0.2 to 0.5 parts by weight based on 100 parts by weight of the base resin powder of aluminum sulfate. It can be included as a wealth.
- the surface crosslinking agent may further include inorganic particles, specifically, hydrophilic inorganic particles, and the superabsorbent polymer prepared accordingly may further include hydrophilic inorganic particles in the surface crosslinking layer.
- the hydrophilic inorganic particles When the hydrophilic inorganic particles are included in the surface crosslinking agent, the hydrophilic inorganic particles efficiently surround the surface crosslinking agent. Accordingly, the surface crosslinking agent is prevented from being quickly absorbed locally only in a part of the base resin powder, so that it can be uniformly applied over the entire surface of the base resin powder. Physical properties such as liquid permeability can be expressed and maintained for a long period of time.
- the hydrophilic inorganic particles may be silica particles or metal oxide particles surface-treated with a compound having a hydrophilic group.
- the metal oxide particles may be aluminum oxide particles or titanium oxide particles.
- commercially available hydrophilic silica particles such as A200 (manufactured by Evonik) may be used as the hydrophilic silica particles.
- hydrophilicity may be defined as a contact angle of 0° to water of inorganic particles measured on a glass substrate.
- the hydrophilic inorganic particles may be included in an amount of 0.005 to 0.2 parts by weight, or 0.01 to 0.1 parts by weight based on 100 parts by weight of the base resin powder.
- water and alcohol may be mixed together and added in the form of the surface crosslinking solution.
- water and alcohol are added, there is an advantage that the surface crosslinking agent can be evenly dispersed in the base resin powder.
- the amount of water and alcohol added is about 5 parts by weight of the polymer for the purpose of inducing even dispersion of the surface crosslinking agent, preventing agglomeration of the base resin powder powder, and optimizing the surface penetration depth of the crosslinking agent. It is preferably added in a proportion of about 12 parts by weight.
- Surface crosslinking by heating for about 15 to about 100 minutes, preferably about 20 to about 80 minutes at a temperature of about 150 to about 220°C, preferably about 165 to about 210°C, for the base resin powder to which the surface crosslinking agent is added. Coupling reactions can take place. When the crosslinking reaction temperature is less than 150°C, the surface crosslinking reaction may not sufficiently occur, and when it exceeds 220°C, the surface crosslinking reaction may proceed excessively.
- the crosslinking reaction time is too short, such as less than 15 minutes, sufficient crosslinking reaction cannot be performed, and if the crosslinking reaction time exceeds 100 minutes, the crosslinking density of the particle surface becomes too high due to the excessive surface crosslinking reaction, resulting in deterioration of physical properties. I can.
- the means for increasing the temperature for the surface crosslinking reaction is not particularly limited. It can be heated by supplying a heat medium or by directly supplying a heat source.
- a heated fluid such as steam, hot air, or hot oil may be used, but the present invention is not limited thereto, and the temperature of the supplied heat medium is the means of the heat medium, the rate of temperature increase, and the temperature increase. It can be appropriately selected in consideration of the target temperature.
- a heat source directly supplied heating through electricity and heating through gas may be mentioned, but the present invention is not limited to the above-described examples.
- the total content of the surface crosslinking agent included in the surface crosslinking solution may be appropriately selected depending on the type of the surface crosslinking agent to be added or reaction conditions, but, based on 100 parts by weight of the base resin powder, about 0.2 to about 2 parts by weight, Preferably, about 0.25 to about 1.5 parts by weight may be used. If the content of the surface crosslinking agent is too small, the surface crosslinking reaction hardly occurs, and if it exceeds 2 parts by weight based on 100 parts by weight of the base resin powder, the absorption capacity and physical properties may be deteriorated due to excessive surface crosslinking reaction. have.
- the moisture content of the surface crosslinked base resin powder obtained by the above method has a range of about 0.1 to about 0.5% by weight.
- This very low moisture content is because most of the moisture in the base resin powder evaporates during heating to a high temperature in the surface crosslinking reaction.
- Such extremely low moisture content brings about a problem that the amount of fine powder is increased in the process of moving and storing the super absorbent polymer.
- the super absorbent polymer having a water content in the above range has a fine powder having a particle size of less than 150 ⁇ m in about 1 to about 5% by weight, which in turn leads to a deterioration in quality of the final product.
- a process of hydrolyzing the surface crosslinked base resin powder by adding water is performed.
- the water content of the final super absorbent polymer may be increased by the hydrolysis treatment as described above to reduce the amount of dust generated, and as a result, process stability may be improved.
- the hydrolysis treatment in step 4 in the production method according to an embodiment of the present invention is performed by pulse spraying water on the surface crosslinked polymer prepared in step 3 above.
- the pulse spraying is performed by using a pulse type spray nozzle in which spraying is turned on/off according to a pulse, such as a pulse jet nozzle, in which water spray is generated at regular time intervals.
- a pulse type spray nozzle in which spraying is turned on/off according to a pulse, such as a pulse jet nozzle, in which water spray is generated at regular time intervals.
- the pulse spraying is performed so that the droplets generated as described above satisfy the scattering index condition defined by Equation 1 above.
- the size of the sprayed droplets affects the moisture content and the amount of coarse particles of the super absorbent polymer, and the size of the droplets is affected by the orifice diameter.
- a spray nozzle having an orifice diameter of 1 to 2 mm, more specifically 1 mm or more, or 1.2 mm or more, and 2 mm or less, or 1.7 mm, may be used.
- the generation of coarse particles can be suppressed while improving the moisture content of the resin. If the diameter of the orifice is less than 1mm, the droplet size is too small to cause flow, and equipment contamination and foreign matter may occur. On the other hand, if the diameter of the orifice exceeds 2mm, the size of the droplet increases, and as a result, the water content of the superabsorbent polymer is excessively increased, so that the water absorption capacity may be lowered. There is.
- the pulse cycle (Hz) during pulse spraying means the number of on/off times per minute.
- the pulse cycle during pulse spraying is 1 to 2000 Hz, more specifically 1 Hz or more. , Or 10 Hz or more, 2000 Hz or less, or 1000 Hz or less, or 500 Hz or less.
- the size of the droplet is also optimized to improve the moisture content of the super absorbent polymer, while suppressing the generation of fine powder and coarse particles.
- the pulse cycle is less than 1 Hz, the pulse effect is weakened, and there is a concern that the effect may decrease due to an increase in the droplet size, and if the pulse cycle exceeds 2000 Hz, the on/off switching is not smooth, so the flow rate changes or the droplet size is changed. There is a fear of deterioration of the effect due to.
- the pulse-on ratio during the pulse spraying that is, the ratio of the time at which spraying occurs according to the application of the pulse during the entire pulse spraying process.
- the pulse-on ratio in the pulse spraying process is pulse It may be 10 to 50%, more specifically 10% or more, or 20% or more, 50% or less, or 35% or less with respect to the total time of the spraying process. If the pulse-on ratio is less than 10%, it is difficult to achieve sufficient water droplets due to the small amount of droplets generated, and if the pulse-on ratio exceeds 50%, aggregation between the hydrolyzed particles occurs due to an excessively high amount of droplets. There is a concern that the content of the coarse particles will increase.
- the absorption rate of the finally produced super absorbent polymer may increase.
- the water absorption rate of the super absorbent polymer exceeds a certain level, the water absorption capacity is rather reduced, and if the water content is too high, the content of coarse particles in the finally prepared super absorbent polymer increases due to agglomeration between the hydrolyzed particles.
- the water input flow rate can be adjusted by the above-described pulse-on ratio, orifice diameter and flow rate, and the spray pressure applied to water during pulse spraying.
- the water input flow rate during pulse spraying is 0.02 to 0.05 m 3 /hr, more specifically 0.02 m 3 /hr or more, or 0.025 m 3 /hr or more, or 0.024 m 3 /hr or more, and 0.05 m 3 /hr or less, or 0.04 m 3 /hr or less, or 0.035 m 3 /hr or less, or 0.03 m 3 /hr or less.
- the flow rate is less than 0.02 m 3 /hr, there is a concern that the effect of increasing the water content by the water will be insignificant, and if the flow rate exceeds 0.05 m 3 /hr, the size of the droplet increases, and as a result, the moisture content of the super absorbent polymer is excessively increased. Absorption capacity may be rather lowered, and there is a concern that the generation of coarse particles having a particle size of more than 850 ⁇ m may increase.
- the droplets generated through the spray nozzle satisfy the conditions of the optimized droplets capable of improving the moisture content of the super absorbent polymer and minimizing the generation of fine particles or coarse particles.
- the condition of such droplets is defined as a scattering index
- the droplets generated during the pulse spraying in the present invention have a scattering index of 5 or more, or 6 or more, or 7.5 or more according to Equation 1 below. , Or 7.8 or more, 10 or less, or 9 or less, or 8.8 or less.
- the generated droplets have a scattering index within the above range, fine droplets with a particle size of 300 ⁇ m or less are reduced to minimize contamination of the reactor, and granules with a particle size of more than 850 ⁇ m by controlling the moisture content in the produced super absorbent polymer The content can be greatly reduced.
- the super absorbent polymer according to an embodiment of the present invention manufactured through the above-described manufacturing process includes: a base resin powder comprising a first crosslinked polymer of a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized; And a surface crosslinked layer formed on the base resin powder and comprising a second crosslinked polymer in which the first crosslinked polymer is further crosslinked via a surface crosslinking agent.
- the surface crosslinking agent contains hydrophilic inorganic fine particles
- the surface crosslinking layer may further include hydrophilic inorganic fine particles derived therefrom.
- the superabsorbent polymer having the above-described configuration and structure has a high water content with excellent absorption ability, and the content of coarse particles exceeding 850 ⁇ m in particle size is minimized, resulting in less dust generation, and as a result, contamination to the reactor can be minimized. Accordingly, according to another embodiment of the present invention, there is provided a super absorbent polymer prepared by the above-described manufacturing method, and articles such as an absorbent material and a sanitary material including the same.
- the superabsorbent polymer is 1 to 5% by weight, more specifically 1% by weight or more, or 1.5% by weight or more, or 1.8% by weight or more, 5% by weight or less, or 3% by weight or less, or 2.5% by weight It has a high moisture content of less than %.
- the moisture content of the super absorbent polymer applied as a product is maintained at an appropriate level, so that the amount of fine powder generated during transport and storage can be reduced, thereby improving the quality of the final product.
- the water content of the super absorbent polymer may be calculated as a value obtained by subtracting the weight of the dry super absorbent polymer from the weight of the super absorbent polymer, and a specific measurement method will be described in detail in the following test examples.
- the super absorbent polymer may have a particle size of 150 to 850 ⁇ m. More specifically, at least 95% by weight or more of the super absorbent polymer has a particle size of 150 to 850 ⁇ m, and the content of coarse particles having a particle size of more than 850 ⁇ m is 5% by weight or less based on the total weight of the super absorbent polymer, Specifically, it is 3% by weight or less, or 2.5% by weight or less, or 2% by weight or less.
- the particle size of the super absorbent polymer can be measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 220.3 method, and the content of granules in the super absorbent polymer is, the super absorbent polymer Was classified on a standard sieve having a scale of 850 ⁇ m (20 mesh), 600 ⁇ m (30 mesh), 300 ⁇ m (50 mesh), and 150 ⁇ m (100 mesh), and 850 ⁇ m (20 mesh)
- the content of the coarse particles relative to the total weight of the super absorbent polymer is expressed as a percentage, and a specific measurement method thereof will be described in detail in Test Examples below.
- the superabsorbent polymer can minimize the content of the superabsorbent polymer attached to the outer wall of the reactor and the rotating body, that is, the degree of contamination, due to the high moisture content and the minimized coarse particle content.
- the weight is measured by separating the superabsorbent polymer attached to the outer wall of the reactor and the rotating body, and calculating the weight ratio of the superabsorbent polymer attached to the weight of the total superabsorbent polymer, that is, the degree of contamination, the value is 2% by weight or less. , Or 1.7% by weight or less.
- the superabsorbent polymer obtained according to the above-described manufacturing method maintains excellent absorption performance, such as water holding capacity and pressure absorption capacity, while increasing the moisture content and reducing the amount of coarse particles, thereby minimizing the amount of dust generated in the manufacturing process. Accordingly, a sanitary material such as a diaper, in particular, an ultra-thin sanitary material having a reduced pulp content, can be appropriately used.
- the monomer composition was supplied at a feed rate of 500 to 2000 ml/min on a rotary belt having a width of 10 cm and a length of 2 m and rotating at a speed of 50 cm/min. Simultaneously with the supply of the monomer composition, ultraviolet rays having an intensity of 10 mW/cm 2 were irradiated, and the polymerization reaction was performed for 60 seconds. After the polymerization reaction proceeds, it was cut by a meat chopper method, dried at 185° C. for 40 minutes using an air-flow oven, and pulverized to prepare a base resin powder.
- a superabsorbent polymer was prepared by performing a hydrolysis process using a pulse type spray nozzle in which water is sprayed only when pulse is applied, that is, when pulse is on. .
- a super absorbent polymer was prepared by performing the same method as in Example 1, except that the hydrolysis process was performed under the conditions described in Table 1 below.
- a super absorbent polymer was prepared by hydrolyzing according to a conventional method without applying a pulse using a normal type spray nozzle.
- a super absorbent polymer was prepared by performing the same method as in Comparative Example 1, except that the hydrolysis process was performed under the conditions described in Table 1 below.
- a super absorbent polymer was prepared by performing the same method as in Example 1, except that the hydrolysis process was performed under the conditions described in Table 1 below.
- the pulse cycle (Hz) is the number of on/off times per minute (Hz)
- the pulse on rate is the ratio of the time at which spraying occurs according to the application of the pulse in the entire pulse spraying process (% )
- the reactor cross-sectional area means the area of the inner section of the reactor perpendicular to the flow direction of air in the reactor.
- Equation 1 Re droplet is the Reynolds number of the droplet
- Re air is the Reynolds number of air
- the Reynolds number of the droplet and the Reynolds number of air may be calculated according to Equation 2 below.
- Reynolds number [(density of fluid ⁇ average flow velocity of fluid ⁇ characteristic length of fluid)/ viscosity coefficient of fluid]
- Equation 2 the fluid is a droplet or air.
- the density of the droplet is 1000 kg/m 3, which is a literature value of water at 25°C.
- the average flow rate of the droplets is the flow rate of the fluid introduced into the reactor, that is, the input flow rate of water (m 3 /hr), the area of the cross-sectional area in the flow direction of the fluid water, that is, the flow of water ( Alternatively, it is calculated by dividing by the area of the orifice cut surface perpendicular to the flow) direction, and the average flow velocity of the droplets in this experimental example is as shown in Table 1 below.
- the characteristic length of the droplet is the average diameter (SMD) of the droplet, and can be measured according to the method described in (2) below, and specific values thereof are as shown in Table 1 below. Further, the viscosity coefficient of the droplet is 10 kg/m/sec, which is a literature value of water at 25°C.
- the density of air is 1.12 kg/m 3, which is a literature value of air at 25°C.
- the average flow rate of air is the flow rate of the air introduced into the reactor, that is, the sweep air flow rate (m 3 /sec), the area of the shape cross-section in the flow direction of air, that is, the cross section inside the reactor perpendicular to the flow direction Calculated by dividing by the area of, and in this experimental example, the inner cut surface of the reactor was calculated as a rectangle, and the area was calculated as the horizontal length ⁇ vertical length of the cut surface, and as a result, the average flow velocity of the air was 0.5 m/s.
- the characteristic length of the air was calculated from the following calculation formula using the conditions of the internal flow, and the characteristic length of the air in this experimental example was 0.933 m.
- Characteristic length of air [4 ⁇ (horizontal length of reactor cut surface ⁇ vertical length of reactor cut surface)] / [2 ⁇ (horizontal length of reactor cut surface + vertical length of reactor cut surface)]
- the horizontal and vertical lengths of the cut surface of the reactor are the horizontal and vertical lengths of the cut surface inside the reactor perpendicular to the flow direction of air.
- the internal section of the reactor was rectangular, the horizontal length was 1.4 m, and the vertical length was 0.7 m.
- the viscosity coefficient of air is 0.17 kg/m/sec, which is the literature value of air at 25°C.
- Example 1 1000 5.42 471 10 0.26 1.12 0.5 0.933 0.17 3.07
- Example 2 1000 4.87 550 10 0.27 1.12 0.5 0.933 0.17 3.07
- Example 3 1000 4.33 530 10 0.24 1.12 0.5 0.933 0.17 3.07 Comparative Example 1 1000 19.14 775 10 1.48 1.12 0.5 0.933 0.17 3.07 Comparative Example 2 1000 4.87 3754 10 1.83 1.12 0.5 0.933 0.17 3.07 Comparative Example 3 1000 15.10 241 10 0.36 1.12 0.5 0.933 0.17 3.07 Comparative Example 4 1000 3.07 273 10 0.08 1.12 0.5 0.933 0.17 3.07 Comparative Example 5 1000 11.37 8
- a droplet particle size measuring device (Sympatec HELOS/KR, manufactured by Sympatec GmbH) by measuring the average diameter (SMD) of droplets generated through the spray nozzle during hydrolysis according to Examples and Comparative Examples, and the ratio of droplets having a diameter of 300 ⁇ m or less among droplets. It was measured by optical diffraction analysis using. The proportion of droplets having a diameter of 300 ⁇ m or less was expressed as a percentage based on the total weight of the generated droplets (% by weight).
- the superabsorbent polymers obtained in Examples and Comparative Examples were 850 ⁇ m (20 mesh), 600 ⁇ m (30 mesh), 300 ⁇ m (50 mesh), and 150 ⁇ m (100 mesh). ), and the water content of the super absorbent polymer particles having a particle size of 150 to 850 ⁇ m was measured.
- the moisture content is the content of moisture (% by weight) occupied with respect to the total weight of the super absorbent polymer, and means a value obtained by subtracting the weight of the dry super absorbent polymer from the weight of the super absorbent polymer.
- the weight loss due to evaporation of water in the super absorbent polymer was measured and calculated in the process of drying by raising the temperature of the super absorbent polymer through infrared heating. In this case, the drying condition was calculated by increasing the temperature from room temperature to about 180°C.
- the total drying time was set to 20 minutes, including 5 minutes of the temperature rise step, in a manner that was maintained at 180°C.
- the superabsorbent polymers obtained in Examples and Comparative Examples were 850 ⁇ m (20 mesh), 600 ⁇ m (30 mesh), 300 ⁇ m (50 mesh), and 150 ⁇ m (100 mesh). ), and after measuring the weight of coarse particles having a size of more than 850 ⁇ m (20 mesh), the content of the coarse particles was expressed as a percentage based on the total weight of the super absorbent polymer (% by weight) ).
- the degree of contamination was calculated from the ratio of the super absorbent polymer attached to the reactor.
- pulse spraying is performed through a pulse-type spray nozzle as in the present invention, but in the case of Comparative Examples 4 and 5 that do not meet the spraying conditions, the scattering index of the droplets was too low or high, and as a result, the degree of contamination The content of coarse particles increased significantly due to a large increase in or due to an excessive increase in the moisture content in the super absorbent polymer.
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Abstract
Description
스프레이 노즐 타입 | 오리피스 직경
(mm) |
오리피스 용량 (l/hr) @3bar | 물의 투입 유량
(m 3/hr) |
sweep air 유량
(m 3/sec) |
반응기 단면적
(m 2) |
분무 압력
(bar) |
펄스 사이클
(Hz) |
펄스 온 비율
(%) |
|
실시예1 | 펄스 타입 | 1.4 | 120 | 0.03 | 0.49 | 0.98 | 3 | 500 | 25 |
실시예2 | 펄스 타입 | 1.4 | 120 | 0.027 | 0.49 | 0.98 | 2.5 | 500 | 25 |
실시예3 | 펄스 타입 | 1.4 | 120 | 0.024 | 0.49 | 0.98 | 2 | 500 | 25 |
비교예1 | 정상 타입 | 1.4 | 120 | 0.106 | 0.49 | 0.98 | 2.5 | - | 100 |
비교예2 | 정상 타입 | 1.4 | 120 | 0.027 | 0.49 | 0.98 | 2.5 | - | 100 |
비교예3 | 정상 타입 | 0.81 | 35.4 | 0.028 | 0.49 | 0.98 | 2.5 | - | 100 |
비교예4 | 펄스 타입 | 1.4 | 120 | 0.017 | 0.49 | 0.98 | 2.5 | 500 | 5 |
비교예5 | 펄스 타입 | 1.4 | 120 | 0.063 | 0.49 | 0.98 | 2.5 | 500 | 60 |
액적의밀도
(kg/m 3) |
액적의 평균 유동 속도
(m/s) |
액적의 SMD
(㎛) |
액적 점성계수
(kg/m/sec) |
액적의 레이놀즈 넘버 | 공기 밀도
(kg/m 3) |
공기 평균 유동 속도
(m/s) |
공기의 특성 길이
(m) |
공기 점성 계수
(kg/m/sec) |
공기의 레이놀즈 넘버 | |
실시예1 | 1000 | 5.42 | 471 | 10 | 0.26 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
실시예2 | 1000 | 4.87 | 550 | 10 | 0.27 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
실시예3 | 1000 | 4.33 | 530 | 10 | 0.24 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
비교예1 | 1000 | 19.14 | 775 | 10 | 1.48 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
비교예2 | 1000 | 4.87 | 3754 | 10 | 1.83 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
비교예3 | 1000 | 15.10 | 241 | 10 | 0.36 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
비교예4 | 1000 | 3.07 | 273 | 10 | 0.08 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
비교예5 | 1000 | 11.37 | 813 | 10 | 0.92 | 1.12 | 0.5 | 0.933 | 0.17 | 3.07 |
비산 지수 | 액적의 레이놀즈 넘버 | 공기의 레이놀즈 넘버 | 액적의 SMD
(㎛) |
300 ㎛ 이하 액적 비율
(중량%) |
함수율
(중량%) |
850 ㎛ 초과 조립자 함량
(중량%) |
오염도
(중량%) |
|
실시예 1 | 8.47 | 0.26 | 3.07 | 471 | 8.4 | 2.4 | 1.7 | 1.4 |
실시예 2 | 8.79 | 0.27 | 3.07 | 550 | 5.6 | 2.3 | 1.6 | 1.7 |
실시예 3 | 7.82 | 0.24 | 3.07 | 530 | 6.5 | 1.8 | 2.4 | 1.6 |
비교예 1 | 48.21 | 1.48 | 3.07 | 775 | 1.7 | 9.4 | 7.2 | 8.7 |
비교예 2 | 59.61 | 1.83 | 3.07 | 3754 | 0.1 | 1.3 | 39.4 | 0.2 |
비교예 3 | 11.73 | 0.36 | 3.07 | 241 | 48.3 | 2.3 | 2.1 | 17.4 |
비교예 4 | 2.61 | 0.08 | 3.07 | 273 | 29.1 | 2.7 | 2.3 | 13.7 |
비교예 5 | 29.97 | 0.92 | 3.07 | 813 | 1.8 | 8.8 | 6.9 | 4.6 |
Claims (15)
- 수용성 에틸렌계 불포화 단량체 및 중합개시제를 포함하는 단량체 조성물에 대해, 열중합 또는 광중합을 진행하여 함수겔상 중합체를 형성하는 단계;상기 함수겔상 중합체를 건조 및 분쇄하여 베이스 수지 분말을 제조하는 단계;상기 베이스 수지 분말에 대해, 표면 가교제를 투입하고 표면 가교 반응 시켜, 표면 가교된 베이스 수지 분말을 제조하는 단계; 및상기 표면 가교된 베이스 수지 분말에 대해, 물을 펄스 분무하여 가수 처리하는 단계;를 포함하며,상기 펄스 분무시 발생되는 액적의 하기 수학식 1에 따른 비산 지수가 5 내지 10인, 고흡수성 수지의 제조 방법:[수학식 1]비산 지수= [(Re droplet)/(Re air)] × 100상기 수학식 1에서 Re droplet은 액적의 레이놀즈 넘버이고, Re air는 공기의 레이놀즈 넘버이다.
- 제1항에 있어서,상기 펄스 분무는, 펄스에 따라 분무가 온/오프 되는 펄스 타입 스프레이 노즐을 이용하여 수행되는, 제조 방법.
- 제2항에 있어서,상기 스프레이 노즐의 오리피스 직경이 1 내지 2mm인, 제조 방법.
- 제1항에 있어서,상기 펄스 분무시, 펄스 온 비율이 총 펄스 분무 시간에 대하여 10 내지 50%인, 제조 방법.
- 제1항에 있어서,상기 펄스 분무시, 물의 투입 유량이 0.02 내지 0.05 m 3/hr인, 제조 방법.
- 제1항에 있어서,상기 펄스 분무시, 펄스 사이클이 1 내지 2000 Hz인, 제조 방법.
- 제1항에 있어서,상기 액적의 레이놀즈 넘버가 0.2 내지 0.35이고, 공기의 레이놀즈 넘버가 2 내지 5인, 제조 방법.
- 제1항에 있어서,상기 액적의 평균 직경이 400 내지 600㎛인, 제조 방법.
- 제1항에 있어서,상기 액적 중 직경 300 ㎛ 이하의 액적 비율이, 발생되는 액적 총 중량에 대하여 5 내지 10중량%인, 제조 방법.
- 제1항에 있어서,상기 표면 가교제가, 다가 알코올계 화합물, 알킬렌 카보네이트계 화합물 및 다가 금속염을 포함하는, 제조 방법.
- 제10항에 있어서,상기 다가 알코올계 화합물이 에틸렌 글리콜, 프로필렌 글리콜, 1,3-프로판디올, 1,4-부탄디올, 1,6-헥산디올, 1,2-헥산디올, 1,3-헥산디올, 2-메틸-1,3-프로판디올, 2,5-헥산디올, 2-메틸-1,3-펜탄디올, 2-메틸-2,4-펜탄디올, 트리프로필렌 글리콜, 또는 글리세롤을 포함하는, 제조 방법.
- 제10항에 있어서,상기 알킬렌 카보네이트계 화합물이, 에틸렌 카보네이트 또는 프로필렌 카보네이트를 포함하는, 제조 방법.
- 제10항에 있어서,상기 다가 금속염이 알루미늄 설페이트, 알루미늄 카르복실레이트 또는 이들이 혼합물을 포함하는, 제조방법.
- 제10항에 있어서,상기 표면 가교제는 친수성 무기 입자를 더 포함하는, 제조 방법.
- 제1항에 있어서,상기 고흡수성 수지는, 고흡수성 수지 총 중량에 대하여 함수율이 1 내지 5 중량%이고, 입자 크기 850㎛ 초과의 조립자 함량이 5중량% 이하인, 제조 방법.
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US17/431,527 US20220111351A1 (en) | 2019-11-05 | 2020-11-05 | Method for Preparing Superabsorbent Polymer |
CN202080013274.8A CN113412301B (zh) | 2019-11-05 | 2020-11-05 | 用于制备超吸收性聚合物的方法 |
BR112021016744A BR112021016744A2 (pt) | 2019-11-05 | 2020-11-05 | Método para preparar polímero superabsorvente |
EP20885848.0A EP3904434B1 (en) | 2019-11-05 | 2020-11-05 | Method for preparing super absorbent polymer |
JP2021547119A JP7246780B2 (ja) | 2019-11-05 | 2020-11-05 | 高吸水性樹脂の製造方法 |
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KR1020200146310A KR102671013B1 (ko) | 2019-11-05 | 2020-11-04 | 고흡수성 수지의 제조 방법 |
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