method of preparing a superabsorbent polymer

专利摘要:
METHOD OF PREPARING SUPERBSORBENT POLYMER AND SUPERABSORBENT POLYMER PREPARED THE SAME The present invention relates to a method for preparing a superabsorbent polymer (SAP) and a SAP prepared therefrom. The method of the present invention includes the steps of preparing a first hydrogel polymer by performing thermal polymerization or photo polymerization of a monomer composition including an ethylene-based, water-soluble unsaturated monomer and a polymerization initiator; preparing a second hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition including an ethylene-based, water-soluble unsaturated monomer and a polymerization initiator; drying and grinding the first hydrogel polymer and distributing the first hydrogel polymer into a fine powder with a particle diameter below 150 (Mi) m and a base resin that has a particle diameter of 150 (Mi) to 850 (Mi) ) m; manufacturing a body reassembled from the fine powder by mixing the fine powder and the second hydrogel polymer; and mixing the refitted body of the fine powder with the first hydrogel polymer, and drying and (...).
公开号:BR112014015719B1
申请号:R112014015719-7
申请日:2013-11-15
公开日:2020-10-27
发明作者:Yong Hun Lee；Kyu Pal Kim；Chang Sun Han；Gi Cheul Kim；Chul Hee Ryu
申请人:Lg Chem, Ltd；
IPC主号:

专利说明:

BACKGROUND OF THE INVENTION (a) Field of the Invention
[001] The present invention relates to a method of preparing a superabsorbent polymer and a superabsorbent polymer prepared therefrom. Specifically, the present invention relates to a method of preparing a superabsorbent polymer with a high water-holding capacity and the aggregation strength of fine powder, without decreasing the absorptive power under pressure and penetrability.
[002] This application claims priority over Korean Patent Applications numbers 10-2012-0129559, filed on November 15, 2012 and 10-2013-0138510, filed on November 14, 2013, and the contents of which are incorporated into this document as a reference. (b) Description of the Related Technique
[003] Superabsorbent polymer (SAP) is a synthetic polymer material that has a water absorption function of about 5 times to about one hundred thousand times its own weight, and which has been differently called superabsorbent material (SAM) ), absorbent gel material (AGM) and so on, through the development of enterprises. The SAP revealed above started to be marketed for sanitary ware and is now being widely used for soil in combination with water for horticulture, a material that holds water in civil engineering and construction, a leaf for use in nursery, a freshness preservative in the field of food distribution, a poultice material, and the like, in addition to sanitary articles, such as a disposable diaper for children.
[004] A method of polymerization of reverse suspension or polymerization of an aqueous solution is known as a method of preparing superabsorbent polymer. For example, reverse suspension polymerization is disclosed in Japanese Patent Publications Numbers Sho56-161408, Sho57-158209, Sho57-198714, and so on. As the aqueous solution polymerization method, a thermal polymerization method is known, polymerizing a hydrogel polymer while fracturing and cooling it in a kneader equipped with a plurality of axes, and a photo-polymerization method that exposes an aqueous solution of high concentration on a belt to UV rays and the like, in order to carry out dry polymerization at the same time.
[005] In general, the hydrogel polymer obtained with said polymerization reaction enters the market in the form of powder, after being dried and crushed.
[006] At this time, fine (fine) powders, with a particle diameter of about 150 pm or less, can be formed during the cutting, grinding and grinding step of the dry polymer. It is considered undesirable to use SAP particles, including fine powders for hygiene items such as baby diapers and an adult urinary incontinence article, as it can be moved before use or may show decreased properties.
[007] Therefore, a process for the exclusion of fine powders is necessary, so that the fine powder is not included in the final product or in the reassembly process for aggregating the fine powder in order to present a normal particle size. At this point, it is important to have a high aggregation force, so that the particles are not crushed again after the reassembly process. The reassembly process is generally carried out in a wet condition to increase the aggregation strength. At this point, the wetter the content of the fine powders, the more aggregation strength, however, it is not easy to handle them in the reassembly process, and the lower the moisture content, the easier the reassembly process, however the aggregation strength is less and powders can be easily crushed again after the reassembly process. SUMMARY OF THE INVENTION
[008] To solve the problems of the prior art, it is an objective of the present invention to provide a method of preparing a SAP with a high water-holding capacity and the aggregating force of fine powder, without decreasing the absorption power under pressure and penetrability and a SAP prepared from it.
[009] To achieve the objective, the present invention provides a method of preparing a SAP, including the steps of: preparing a first hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition including an unsaturated monomer based on ethylene, soluble in water and a polymerization initiator; preparing a second hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition including an ethylene-based, water-soluble unsaturated monomer and a polymerization initiator; drying and grinding the first hydrogel polymer and distributing the first hydrogel polymer into a fine powder with a particle diameter below 150 pm and a base resin having a particle diameter from 150 pm to 850 pm; fabricating a refitted body of the fine powder by mixing the fine powder and the second hydrogel polymer; and mixing the reassembled body of the fine powder with the first hydrogel polymer, and drying and grinding the reassembled body of the fine powder and mixed with the first hydrogel polymer, in which the second hydrogel polymer has a greater water retention capacity than the first hydrogel polymer.
[0010] The present invention also provides an SAP prepared by the method.
[0011] In accordance with the present invention, it is possible to obtain a superabsorbent polymer with high water-holding capacity and fine aggregating force of the powder, without decreasing the absorption power under pressure and penetrability. DETAILED DESCRIPTION OF THE MODALITIES
[0012] The method of preparing an SAP, including the steps of: preparing a first hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition including an unsaturated ethylene-based, water-soluble monomer and a polymerization initiator; preparing a second hydrogel polymer by carrying out a polymerization or thermal photo polymerization of a monomeric composition including an ethylene-based, water-soluble unsaturated monomer and a polymerization initiator; drying and grinding the first hydrogel polymer and distributing the first hydrogel polymer into a fine powder with a particle diameter below 150 pm and a base resin having a particle diameter from 150 pm to 850 pm; fabricating a refitted body of the fine powder by mixing the fine powder and the second hydrogel polymer; and mixing the reassembled body of the fine powder with the first hydrogel polymer, and drying and grinding the reassembled body of the fine powder and mixed with the first hydrogel polymer, where the second hydrogel polymer has a greater water retention capacity than the first hydrogel polymer.
[0013] And, the SAP of the present invention is prepared by said method.
[0014] Since the present invention can be modified in various ways and present several examples, specific embodiments of the present invention are explained in this description. However, it is not intended to limit the present invention to specific examples and it is to be understood that the present invention includes all modifications, equivalents or substitutes included in the idea and technical scope of the present invention.
[0015] The SAP preparation process of the present invention and the SAP prepared from it are explained in more detail below.
[0016] According to one embodiment of the present invention, it provides a method of preparing a SAP, including the steps of: preparing a first hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition including a water-soluble unsaturated monomer based on ethylene and a polymerization initiator; preparing a second hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition which includes an ethylene-based, water-soluble unsaturated monomer and a polymerization initiator; drying and grinding the first hydrogel polymer and distributing the first hydrogel polymer into a fine powder, with a particle diameter below 150 pm and a base resin that has a particle diameter from 150 pm to 850 pm; manufacturing a body reassembled from the fine powder by mixing the fine powder and the second hydrogel polymer; and mixing the reassembled fine powder body with the first hydrogel polymer, and drying and grinding the reassembled fine powder body mixed with the first hydrogel polymer, where the second hydrogel polymer has a greater water holding capacity than the first hydrogel polymer.
[0017] In the SAP preparation method of the present invention, the first hydrogel polymer is prepared by performing thermal polymerization or photo polymerization of the monomeric composition including the water-soluble ethylene-based unsaturated monomer and the polymerization initiator.
[0018] The monomeric composition, the raw material for SAP, includes an unsaturated ethylene-based monomer, soluble in water and the polymerization initiator.
[0019] As the unsaturated ethylene-based monomer, soluble in water, any monomer that is used in general for the preparation of SAP can be used without restrictions. For example, one or more monomers selected from the group consisting of an anionic monomer and a salt thereof, a nonionic hydrophilic monomer and an unsaturated monomer containing amino group and a quaternary compound can be employed.
[0020] Specifically, one or more compounds selected from the group consisting of an anionic monomer, such as (meth) acrylic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acrylate ethyl sulfonic acid, 2 - (met ) sulfonic acrylate ethane, 2- (meth) acryloylpropane sulfonic acid and 2- (meth) acrylamide-2-methyl propane sulfonic acid and a salt thereof; a non-ionic hydrophilic monomer, such as (meth) acrylamide, N-substituted (meth) acrylate, 2-hydroxypropyl (meth) acrylate, methoxypolyethylene glycol acrylate and (poly) polyethylene glycol acrylate and an unsaturated monomer containing amino group , such as (N, N) dimethylaminoethyl (meth) acrylate and (N, N) - dimethylaminopropyl (meth) acrylate and a quaternary compound thereof can be employed.
[0021] More preferably, acrylic acid or a salt thereof, for example, acrylic acid or an alkali metal salt such as sodium acrylate, can be used. By using such a monomer, it becomes possible to prepare the SAP showing better properties. In the case of using the alkali metal salt of acrylic acid, it is possible to use acrylic acid, then neutralize it with a basic compound such as sodium hydroxide (NaOH).
[0022] The concentration of unsaturated ethylene-based monomer, soluble in water can be about 20 to about 60% by weight, preferably about 40 to about 50% by weight, in the monomeric composition, including the materials - SAP raw materials and the solvent, which can be controlled in order to be an adequate concentration, considering the polymerization time and reaction conditions. However, when the monomer concentration is too low, the SAP yield will be low and there may be a problem with the economy. Conversely, when the concentration is very high, there may be problems with the process, so that part of the monomer can be extracted or the grinding efficiency of the prepared hydrogel polymer appears to be low in the grinding process, and thus the SAP properties may decline.
[0023] In the SAP preparation method of the present invention, the polymerization initiator used in the polymerization is not particularly limited if it is the one generally used for the preparation of SAP.
[0024] Concretely, the polymerization initiator can be a thermal polymerization initiator or a photo polymerization initiator by UV radiation, according to the polymerization method. However, even in the case of photo polymerization method, a thermal polymerization initiator can be additionally included since a certain amount of heat is generated by the irradiation of UV rays and the like, and a certain amount of heat is generated according to the progress of the exothermic polymerization reaction.
[0025] Any compound that can form a radical by light, such as a UV ray can be used, without restrictions, as the initiator of photo polymerization.
[0026] The photo polymerization initiator, for example, can be at least one initiator selected from the group consisting of benzoin ether, dialkyl acetophenone, hydroxyl alkyl ketone, phenyl glyoxylate, benzyl dimethyl ketal, acyl phosphine and an α-aminoketone. However, as the specific example of acyl phosphine, Lucirin TPO that is commercialized can be mentioned, that is, 2,4,6-trimethyl-benzoyl-trimethyl phosphine oxide. Several other photo polymerization initiators are well publicized in "UV Coatings: Basics, Recent Developments and New Application" by Reinhold Schwalm, (Elsevier, 2007), pll5, however, the example of photo polymerization initiator is not limited to the same.
[0027] The concentration of the photo polymerization initiator can be from about 0.005 to about 1.0% by weight in the monomeric composition. When the concentration of the photo polymerization initiator is too low, the polymerization rate will become slow and, when the concentration of the photo polymerization initiator is too high, the molecular weight of SAP will become low and the properties may become unstable.
[0028] As the thermal polymerization initiator, at least one initiator selected from the group consisting of a persulfate based initiator, an azo based initiator, hydrogen peroxide and ascorbic acid can be used. As a specific example of the persulfate-based initiator, there are sodium persulfate (Na2S20s), potassium persulfate (K2S2O8), ammonium persulfate ((NH4) 2S2O8) and the like, - and as the example of the azo-based initiator, dihydrochloride 2,2-azobis (2-amidinopropane), 2,2-azobis- (N, N-dimethylene) isobutyramidine dihydrochloride; 2- (carbamoylazo) isobutylonitrile dihydrochloride, 2,2-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride and 4,4-azo-bis- (4-cyanovaleric acid) can be used. Several other thermal polymerization initiators are well disclosed in Odian's "Principle of Polymerization" (Wiley, 1981), p203, however, the example of the thermal polymerization initiator is not limited to or by the same.
[0029] The concentration of the thermal polymerization initiator can be from about 0.001 to about 0.5% by weight in the monomeric composition. When the concentration of the thermal polymerization initiator is too low, additional thermal polymerization is unlikely to occur and the effect of adding the thermal polymerization initiator may be weak, in addition, when the concentration of the thermal polymerization initiator is very high, the weight molecular weight of SAP will be low and properties may become unstable.
[0030] According to an embodiment of the present invention, the monomeric composition can also include an internal cross-linking agent as the raw material for SAP. The internal cross-linking agent can be a cross-linking agent having one or more ethylene-based unsaturated functional groups, in addition to the functional group that can react with the water-soluble water-soluble monomer substituents; or a cross-linking agent having two or more functional groups that can react with the water-soluble substituents of the monomer and / or the water-soluble substituents formed by hydrolysis of the monomer.
[0031] As a specific example of the internal cross-linking agent, a C8-C12 bisacrylamide, bismethacrylamide, a C2-C10 polyol (meth) acrylate or a C2-C10 polyol poly (meth) alkyl, and so on can be used and, more specifically, one or more agents selected from the group consisting of N, N'-methylene-bis acrylate, ethylenoxy (meth) acrylate, polyethyleneoxy (meth) acrylate, (meth) acrylate propylenoxy, glycerin diacrylate, glycerin triacrylate, trimethylol triacrylate, trialylamine, triarylcyanurate, triarylisocyanate, polyethylene glycol, diethylene glycol and propylene glycol can be used.
Such an internal cross-linking agent can be included in the monomer composition with a concentration of about 0.001 to about 2.0% by weight, and can cross-link the prepared polymer.
[0033] In the method of preparing the present invention, the monomeric composition of SAP can further include additives, such as, a thickening agent, a plasticizer, an expiration stabilizer, an antioxidant, and so on.
[0034] The monomeric composition can be prepared in the form of a solution so that the raw materials, such as unsaturated monomer based on water soluble ethylene, photo polymerization initiator, thermal polymerization initiator, internal crosslinking agent, and the additives are dissolved in a solvent.
[0035] At this time, any solvent that can dissolve said components can be used without limitation, for example, one or more solvents selected from the group consisting of water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol , propylene glycol, ethylene glycol monobutyl, propylene glycol monomethyl, ethylene glycol monobutyl, propylene glycol monomethyl, monomethyl ether, ethylene ethylene, cyclohexyl, ethylene glycol, diethylene, cyclone, cyclone , xylene, butylolactone, carbitol, methylcellosolve acetate and N, N-dimethyl acetamide and others can be used alone or in combination.
[0036] The solvent can be included in the monomeric composition in the residual amount excluding the components described above.
[0037] Meanwhile, the general method can be used without limitation, as long as the method can prepare a hydrogel polymer from such a monomeric composition, carrying out thermal polymerization or photo polymerization.
[0038] Specifically, the polymerization method is widely classified as a thermal polymerization and the photo polymerization according to the polymerization energy source, at this moment, the thermal polymerization can be carried out in the reactor as a kneader equipped with stirring spindles and the photo polymerization can be carried out in the reactor equipped with a mobile conveyor belt, however, the polymerization methods described above are only examples and the present invention is not limited to the polymerization methods described above.
[0039] For example, the hydrogel polymer obtained from thermal polymerization in the kneader-like reactor equipped with the agitation spindles described above, providing hot air to it or heating the reactor can be the size of centimeters or mL when it is discharged from the reactor outlet, according to the type of agitation spindles equipped in the reactor. Specifically, the size of the hydrogel polymer obtained can be shown varying according to the concentration of the monomeric composition fed to it, feed rate, and so on, and the hydrogel polymer, the average particle diameter by weight of the same being 2 to 50 mm can be obtained in general.
[0040] In addition, in the case of the photo polymerization carried out with the reactor equipped with the mobile conveyor belt described above, the hydrogel polymer obtained may be a sheet-type hydrogel polymer that has the same width as the belt. At that time, the thickness of the polymer sheet may vary according to the concentration of the monomer composition fed and the rate of feed, it being preferable to provide the monomer composition so that the sheet-type hydrogel polymer with a width of about 0, 5 to about 5 cm is obtained. It is not preferable for the monomeric composition to be fed so that the thickness of the polymer sheet type becomes very thin, since the production efficiency will be reduced, and when the thickness of the polymer sheet type is greater than 5 cm , the polymerization reaction cannot occur uniformly over the entire thickness, due to its excessively thick thickness.
[0041] According to an embodiment of the present invention, the moisture content of the first hydrogel polymer obtained by this method can be from about 30 to about 60% by weight and preferably from about 40 to about 55% by weight. Weight. Meanwhile, throughout this specification, "moisture content" means the moisture content by weight of the total hydrogel polymer, and that means the value by which the weight of the dry polymer is subtracted from the weight of the hydrogel polymer . Specifically, the water content is defined as the value calculated by measuring the weight loss, as the water is evaporated from the polymer during the drying process, by raising the temperature of the polymer through infrared heating. At this time, the moisture content is measured by carrying out the dry process with the condition of drying the temperature rise from room temperature to 180 ° C and maintaining the temperature at 180 ° C, in which the total drying time is defined in 20 minutes including 5 minutes of temperature rise stage.
[0042] Regardless, the second hydrogel polymer is prepared by performing thermal polymerization or photo polymerization of the monomeric composition including the water-soluble ethylene-based unsaturated monomer and the polymerization initiator.
[0043] The details of the ethylene-based monomer, soluble in unsaturated water, polymerization initiator, solvent, internal crosslinking agent, and additives that are raw materials for the second hydrogel polymer are the same as those of the preparation of the first hydrogel polymer described above.
[0044] The second hydrogel polymer of the present invention can be prepared using the same or different raw materials as those of the first hydrogel polymer.
[0045] The second hydrogel polymer of the present invention has greater water retention capacity (CRC) than the first hydrogel polymer, when it is measured according to the EDANA WSP 241.2 method. For example, the first hydrogel polymer can have a water holding capacity of about 30 g / g or more, preferably about 30 to about 55 g / g, and the second hydrogel polymer can have the ability to water retention of about 35 g / g or more, preferably about 35 to about 60 g / g.
[0046] In addition, the second polymer of the present invention has a higher content of water-soluble component than the first polymer, when it is measured according to the EDANA WSP 270.2 method. For example, the first polymer can have a water-soluble component content of about 5 to about 30% by weight and the second polymer can have a water-soluble component content of about 6 to about 35% by weight . The water-soluble component means the low molecular weight polymer, which is soluble in water.
[0047] As disclosed above, since the second polymer of the present invention includes a higher water-soluble component content than the first polymer, the viscosity and the binding function of the second polymer are improved which makes it possible to increase the strength of connection between fine powders in the following reassembly step.
[0048] The moisture content of the second hydrogel polymer of the present invention can be from about 30 to about 60% by weight and preferably from about 40 to about 55% by weight.
[0049] The characteristics of the second polymer of the present invention, such as the water holding capacity, moisture content, water-soluble component content, and the like can be achieved through proper regulation of the process conditions of the polymerization process of the second polymer. For example, the second polymer that has a greater water-holding capacity than the first polymer can be prepared by decreasing the amount of crosslinking agent used, or increasing the amount of the initiator used. 5
[0050] Then, the first hydrogel polymer obtained is dried.
[0051] At this time, a coarse grinding step can be additionally performed, before the drying step to increase the efficiency of the drying phase, as needed.
[0052] There is no limitation of the grinding machine currently used. For example, any device selected from the group consisting of a vertical sprayer, a turbo cutter, a turbo mill, rotary cutting mill, a cutting mill, disc mill, fragmentation crusher, crusher, a cutter and a disc cutting tools can be used, but is not limited to those by the said examples.
[0053] The coarse grinding step can be carried out so that the diameter of the particles of the first polymer is about 2 to about 10 mm.
[0054] Technically it is not easy to coarsely grind the first hydrogel polymer to a size of less than 2 ml, due to its high moisture content, and coarse ground particles can agglomerate when the diameter of the particles is less than 2 mm. On the other hand, when the particle diameter is greater than 10 mm, the effect of increasing the efficiency of the subsequent drying step can be insignificant.
[0055] The first polymer obtained after polymerization, which is coarsely ground or is not dried. At this time, the drying temperature can be from about 150 ° C to about 250 ° C. When the drying temperature is below 150 ° C, there is a concern that the drying time will become excessively long or the properties of the superabsorbent polymer formed will eventually deteriorate, and when the drying temperature is greater than 250 ° C, only the surface of the polymer is dry and, therefore, there is a concern that the fine powder may be generated and the properties of the superabsorbent polymer formed will eventually deteriorate. The drying temperature can preferably be about 150 ° C to about 200 ° C, and more preferably about 160 to about 180 ° C.
[0056] Meanwhile, the drying time can be about 20 to about 90 minutes, considering the efficiency of the process, but it is not limited to the same or at least.
[0057] Any general drying method that can be used to dry the hydrogel polymer can be used in the drying phase, without limitation. Specifically, the drying step can be carried out by the method of supplying hot air, radiating an infrared ray, with microwave irradiation, or with irradiation of an ultraviolet ray and the like. After the drying step described above is carried out, the moisture content of the first hydrogel polymer can be from about 0.05 to about 5% by weight.
[0058] Subsequently, the first dry polymer obtained through the drying step is ground. It is preferable that the particle diameter of the powdered polymer obtained after the milling step is from about 150 pm to about 850 pm. The milling device used for grinding the polymer to the particle diameter can be a pin mill, hammer mill, spindle mill, roller mill, disc mill, rotary mill, and the like, in particular, but the present invention is not limited to or by the examples above.
[0059] In the grinding step, fine powder with a diameter of less than about 150 pm can be formed. The fine powder below a certain particle size, for example, below about 150 pm, is generally referred to as the ultra-absorbent polymer fine powder, the fine SAP powder or the fine ones. The fine powder can be formed not only in the grinding step, but also in the transfer step. If the fine powder is included in a product, handling will be difficult and can cause a gel blocking phenomenon and deteriorate properties. Therefore, it is preferable to exclude the fine powder or reuse the fine powder as a normal particle, so that the final resin product does not include the same.
[0060] Therefore, the first ground polymer is distributed in the fine powder with the particle diameter below 150 pm and the base resin having the particle diameter from 150 pm to 850 pm.
[0061] As an example of reusing fine powder, the reassembly process can be carried out to aggregate the fine powders to a normal particle size from about 150 pm to about 850 pm. The reassembly process is generally carried out in a high temperature condition or while spraying steam to increase the aggregation strength. At this time, the more moisture content, the more aggregation strength, but handling is not easy in the reassembly process, and the lower the moisture content, the easier the reassembly process, but the aggregation strength is low and can be easily crushed again after the reassembly process.
[0062] According to the preparation method of the present invention, the reassembly step is carried out by mixing the fine powders having a diameter below 150 pm with the second hydrogel polymer. At this time, the second hydrogel polymer may be in a water-free swelling state. In the present invention, the "water-free state" means the state in which the second polymer absorbs water and swells without limit load.
[0063] Water can be added to the second hydrogel polymer prepared to free the swelling of the second polymer with water. Or, after drying the second hydrogel polymer prepared from the polymerization process, the second dry polymer can be free of swelling by providing water. In addition, after drying the second polymer and before swelling it with water, a grinding step to obtain the second polymer of suitable particle size or a distribution step can be carried out in addition.
[0064] The second water-free swelling polymer can contain about 50 to about 5.000% by weight, preferably about 50 to about 200% by weight, of water, based on the total weight of the second polymer.
[0065] Since the second hydrogel polymer has a high moisture content, it can perform the functions of a water transfer medium to provide moisture to fine powders and a binder to aggregate fine powders at the same time. Therefore, it is possible to aggregate the fine powders more evenly and to manufacture the reassembled polymer with a high aggregation force, instead of just water being supplied to the fine powders.
[0066] According to an embodiment of the present invention, the second hydrogel polymer can be in a state before grinding after the polymerization step or a state after polymerization, drying and grinding processes unlimitedly, if the second hydrogel polymer is in a hydrated or water-free state.
[0067] And, as described above, since the second hydrogel polymer of the present invention is prepared in order to have a greater water holding capacity than the first polymer, the reassembled polymer formed by aggregating it with the powders can also have a high water holding capacity.
[0068] According to an embodiment of the present invention, it is possible to assemble the powder by mixing about 10 to about 200 parts by weight of the second hydrogel polymer with 100 parts by weight of the fine powder, preferably through the mixing about 20 to about 150 parts by weight of the second hydrogel polymer with 100 parts by weight of the fine powder. When the second hydrogel polymer that is free of swelling with water is mixed with the fine particles, in an appropriate proportion, it will be possible to show the effect of increasing the aggregation force due to said mixture.
[0069] Through the reassembly process, fine powders are aggregated and the reassembled body of the fine powder is formed. The reassembled body of the fine powder can have the particle diameter over about 150 pm and not exceeding 50 mm, and preferably the particle diameter from about 300 pm to about 30 mm. In addition, the phenomenon in which the reassembled body is ground into fine powders is minor, even in the following drying, grinding, and surface treatment steps, because the reassembled body of the fine powder of the present invention has a high aggregating force.
[0070] The reassembled body of the fine powder is mixed with the first hydrogel polymer. The first hydrogel polymer is the hydrogel polymer prepared by the polymerization of the monomeric composition prior to the drying step in the step of preparing the first polymer disclosed above. In addition, it can be mixed with the first polymer which is coarsely ground after the polymerization step.
[0071] After the step of mixing the refitted body of the fine powder and the first hydrogel polymer, the final SAP can be obtained by carrying out the additional step of drying and grinding the mixed polymer, that is, the polymer that has the reassembled body of the fine powder mixed with the first hydrogel polymer. At this point, the efficiency of the process can be achieved by introducing the polymer mixture, in which the refitted body of the fine powder and the first hydrogel polymer are mixed in the process of preparing the final SAP from the first polymer and drying and grinding initial the same.
[0072] At this time, the drying temperature and drying time of the drying step are the same as those of the drying method of the first hydrogel polymer described above.
[0073] After carrying out the drying process, the moisture content of the polymer mixture can be from about 0.05 to about 5% by weight.
[0074] The method may also include the step of crosslinking the surface of the polymer mixture. And, the method can further include the step of grinding or distributing the polymer mixture between the drying step and the crosslinking step of the polymer mixture surface, so that the polymer mixture has a particle size suitable to be marketed.
[0075] The crosslinking step of the surface is intended to increase the crosslinking density, close to the surface of the SAP particles, in relation to the crosslink density inside the particles. Generally, the surface crosslinking agent is coated on the surface of the SAP particles. Thus, the reaction occurs on the surface of the SAP particle, and does not substantially influence the interior of the particles and improves the crosslinking property of the particles' surface. As a result, the SAP particles cross-linked to the surface show a higher degree of cross-linking, close to the surface than inside.
[0076] At this time, the surface crosslinking agent is not limited, specifically, if it is a compound that can react with the functional group of the polymer.
[0077] In order to improve the characteristics of SAP, one or more surface crosslinking agents selected from the group consisting of a polyhydric alcohol compound; an epoxy compound; a polyamine compound; a haloepoxy compound; an oxazoline compound; a mono, di or polyoxazolidinone compound; a cyclic urea compound; a polyvalent metal salt; and an alkylene carbonate compound can be employed.
[0078] Specifically, as the example of the polyhydric alcohol compound, one or more compounds selected from the group consisting of a mono, di, tetra or polyethylene glycol, monopropylene glycol, 1,3-propanediol, dipropylene glycol group , 2,3,4-trimethyl-1,3-pentanediol, polypropylene glycol, glycerol, polyglycerol, 2-butene-1,4-diol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol and 1,2-cyclohexane dimethanol can be used
[0079] And, as in the example of the epoxy compound, diglycidyl ether ethylene glycol and glycidol can be used, and as the polyamine compound, one or more compounds selected from the group consisting of ethylene diamine, diethylene triamine, triethylene triamine, tetraethylene pentamine, pentaethylene hexamine, polyethylene amine, and polyamide polyamine can be used.
[0080] E, epichlorohydrin, epibromhydrin, and α-methylpichlorohydrin can be used as the haloeppoxy compound. 2-oxazolidinone, for example, can be used as a mono-, di- or polyoxazlidinone compound.
[0081] And, ethylene carbonate can be used as the alkylene carbonate compound. These compounds can be used alone or in combination. However, in order to increase the efficiency of the surface cross-linking reaction process, it is preferable to use one or more polyhydric alcohol compounds among said surface cross-linking agent, and it is more preferable to use a poly-alcohol compound water C2-C10.
[0082] The amount of additional surface crosslinking agent can be adequately regulated according to the type of surface crosslinking agent or reaction conditions, and normally the amount can be from about 0.001 to about 5 parts by weight, preferably about 0.01 to about 3 parts by weight, and more preferably about 0.05 to about 2 parts by weight per 100 parts by weight of the polymer.
[0083] When the amount of surface cross-linking agent used is very small, the surface cross-linking reaction may not have occurred in practice, and when the amount is greater than 5 parts by weight per 100 parts by weight of the polymer, the water holding capacity and properties can be decreased due to the excessive surface crosslinking reaction.
[0084] The surface cross-linking and drying reaction can be carried out at the same time by heating the polymeric particles to which the surface cross-linking agent is added.
[0085] The means for raising the temperature of the surface crosslinking reaction are not specifically limited. For example, a heating medium can be provided or a heat source can be provided directly to raise the temperature. At this time, a hot fluid, such as steam, hot air, hot oil, and the like can be used as a usable heating medium, however the present invention is not limited to or by them. And the temperature of the heating medium can be appropriately selected, considering the means of the heating medium, the speed of temperature rise and the target temperature. However, as the directly supplied heat source, an electric heating or gas heating system can be used, but the present invention is not limited to or by them.
[0086] SAP with high water retention capacity and fine powder aggregation strength can be obtained according to the preparation method of the present invention. For example, SAP prepared according to the preparation method of the present invention can have a water holding capacity of about 20 to about 50 g / g, and preferably about 25 to about 45 g / g, and it can have a fine powder content of about 5% by weight or less, preferably about 4% by weight or less, and more preferably about 3% by weight or less.
[0087] In accordance with another embodiment of the present invention, a SAP prepared by the method of preparation is provided.
[0088] More specifically, in the SAP of the present invention, the fine powder content of which the particle diameter is less than 150 pm is about 5% by weight or less, preferably about 4% by weight or less, and more preferably about 3% by weight or less.
[0089] Furthermore, the SAP of the present invention can show greater penetration of about 200 seconds or less, for example, about 50 to about 200 seconds, and preferably about 60 to about 200 seconds, and more preferably about 60 to about 180 seconds and, when measured according to the 21 g / cm2kPa load, using a 0.9% brine solution. And, SAP can have a water holding capacity of about 20 to about 50 g / g, and preferably about 25 to about 45 g / g, when measured according to the EDANA WSP 241.2 method.
[0090] The SAP of the present invention can be prepared by the SAP preparation method disclosed above.
[0091] Hereinafter, the present invention will be explained in more detail by means of the following examples. However, the following examples are only to illustrate the present invention, and the scope of the present invention is not limited to them. EXAMPLES Methods for measuring the properties of the superabsorbent polymer Strength of refitted body from fine powder
[0092] The strength of the refitted body of the fine powder was measured through a ball mill test by measuring the content of fine powders that were regenerated from the refurbished body of the fine powder. The ball mill test was carried out according to the method of measuring the content of fine powders with a diameter of less than 150 pm after placing 20 g of sample and 10 glass beads with a diameter of 15 mL in a container of 200 ml and grinding the sample at a rotation speed of 150 rpm for 30 minutes. The lower content of fine powders that were regenerated after the ball mill test may indicate the higher aggregation strength. Water holding capacity
[0093] The water holding capacity was measured according to the EDANA WSP 241.2 method. After inserting 0.2 g of the sample in a tea bag and soaking it in 0.9% brine solution for 30 minutes, the water holding capacity was measured by the method of eliminating water from the sample. , for 3 minutes, with a centrifugal separator set to 250 g and weighing the sample, in order to determine the amount of brine solution retained in the superabsorbent polymer. Absorption power under pressure
[0094] The absorption power under pressure was measured according to the EDANA WSP 242.2 method. After distributing 0.9 g of the sample evenly inside a measuring cylinder and pressing the sample with a pressure of 49.2 g / cm2 using a plunger and a weight, the sample was transferred to a shale in which the 0.9% brine solution was contained and absorbed the solution for 60 minutes. The absorptive power under pressure was calculated by dividing the weight gain after 60 minutes by the weight of the sample. Penetration
[0095] Penetrability was measured using 0.9% brine solution under a load of 21 g / cm2 according to the method described in the literature (Buchholz, FL and Graham, EM, "Modern Superabsorbent Polymer Technology" John Wiley & Sons (1998), page 161).
[0096] After placing 0.2 g of the sample in a prepared cylinder, 50 g of 0.9% brine solution were added and left as they were for 30 minutes. Then, the weight of 21 g / cm2 was placed on the sample in which 0.9% brine solution was absorbed and left to stand for 1 minute. And then, the time it took the 0.9% brine solution to pass from the upper limit line to the lower limit line previously marked on the cylinder was measured after opening the stopcock at the bottom of the cylinder. Each measurement was performed at a temperature of 24 ± 1 ° C and a relative humidity of 50 ± 10%.
[0097] The passage time from the upper limit line to the lower limit line was measured for each sample and the passage time without SAP was measured. Equation 1 Penetrability (s) = hour (sample) - Time (without SAP) Preparation of Superabsorbent Polymer Preparation Example 1
[0098] After placing 500 g of acrylic acid and 2.5 g of (15) ethoxylated trimethylolpropane triacrylate in a 3 L glass container equipped with a stirrer, a nitrogen feeder and a thermocouple and dissolving them, the aqueous solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5% sodium hydroxide solution, while continuously feeding nitrogen. The aqueous solution of water-soluble unsaturated monomer was placed in a 5L double-sided kneader with sigma-shaped spindles, and the oxygen dissolved in the aqueous solution was eliminated by the nitrogen supply at 75 ° C. While stirring the solution, 40 g of 0.3% aqueous solution of L-ascorbic acid and 40 g of aqueous solution and 0.25 g of potassium persulfate and 3.0 g of hydrogen peroxide were dissolved in 100 g of water and added.
[0099] The gel-type resin was formed as the polymerization proceeded, and the microgel-type hydrogel polymer was prepared by stirring for 30 minutes and separating the gel-type resin. The moisture content of the obtained hydrogel polymer was 40.5%.
[00100] The hydrogel polymer was spread on a stainless steel wire screen, with the orifice size of 600 pm at a thickness of about 30 mm and dried in a hot air oven at 170 ° C for 5 hours. The dry polymer was ground using a milling machine and the base resin having a particle size of 150 pm ~ 850 pm and the fine powder with a particle diameter less than 150 pm were obtained by distributing the ground polymer with a standard screen according to the ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00101] The water retention capacity obtained by the base resin was 40.5 g / g, and the content of the water-soluble component was 11.4%. Preparation Example 2
[00102] After placing 500 g of acrylic acid and 0.5 g of 1,6-hexanediol diacrylate (HDDA), in a 3 L glass container equipped with a stirrer, a nitrogen feeder, a thermocouple and dissolution of these, the aqueous solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5% sodium hydroxide solution the same, while feeding it nitrogen continuously. The aqueous solution of water-soluble unsaturated monomer was placed in a double-blade kneader with a capacity of 5 L with sigma-shaped spindles, and the oxygen dissolved in the aqueous solution was eliminated by feeding nitrogen at 85 ° C. While the solution was stirring, 40 g of 0.3% aqueous solution of L-ascorbic acid and 40 g of aqueous solution, 5.0 g of potassium persulfate and 3.0 g of hydrogen peroxide were dissolved in 100 g of water. The gel-type resin was formed as polymerization proceeded, and the microgel-type hydrogel polymer was prepared by stirring it for 30 minutes and separating the gel-type resin. The moisture content of the obtained hydrogel polymer was 40.1%. The hydrogel polymer was spread on a stainless steel wire screen, with the orifice size of 600 pm with a thickness of about 30 ml and dried in a hot air oven at 180 ° C for 5 hours. The dry polymer was ground using a grinding machine and the base resin having a particle size of 150 pm ~ 850 pm and the fine powder with a particle diameter less than 150 pm were obtained by distributing the ground polymer with a sieve. standard according to the ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00103] The water retention capacity of the base resin was 50.1 g / g, and the content of the water-soluble component was 21.4%. Preparation Example 3
[00104] After placing 500 g of acrylic acid and 3.75 g of (15) ethoxylated trimethylolpropane triacrylate in a 3 L glass container equipped with a stirrer, a nitrogen feeder, and a thermocouple and dissolving it, the aqueous solution of water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5% sodium hydroxide solution, while the nitrogen feed continued continuously. The aqueous solution of water-soluble unsaturated monomer was placed in a 5 L double-capacity kneader with sigma-shaped spindles, and the oxygen dissolved in the aqueous solution was eliminated by feeding nitrogen at 75 ° C. While stirring the solution, 20 g of 0.3% aqueous solution of L-ascorbic acid and 30 g of aqueous solution, 1.25 g of potassium persulfate and 3.0 g of hydrogen peroxide were dissolved in 100 g of water.
[00105] The gel-type resin was formed as the polymerization proceeded, and the microgel-type hydrogel polymer was prepared by stirring it for 30 minutes and separating the gel-type resin. The moisture content of the obtained hydrogel polymer was 40.2%. The hydrogel polymer was spread on a stainless steel wire, with the orifice size of 600 pm with a thickness of about 30 mm, and dried in a hot air oven at 160 ° C for 5 hours. The dry polymer was ground using a milling machine and the base resin having a particle size of 150 pm ~ 850 pm and the fine powder with a particle diameter less than 150 pm were obtained by distributing the ground polymer with a standard screen according to the ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00106] The water retention capacity of the base resin was 3 6.2 g / g, and the content of the water-soluble component was 7.3%. Preparation Example 4
[00107] After placing 500 g of acrylic acid and 1.5 g of 1,6-hexanediol diacrylate (HDDA) in a 3 L glass container equipped with a stirrer, a nitrogen feeder and a thermocouple and dissolve the even, the aqueous water solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5% sodium hydroxide solution, while the nitrogen feeding continued continuously. The aqueous solution of water-soluble unsaturated monomer was placed in a double-blade kneader with a capacity of 5 L with sigma-shaped spindles, and the oxygen dissolved in the aqueous solution was eliminated by feeding nitrogen at 75 ° C. While stirring the solution, 20 g of 0.3% aqueous solution of L-ascorbic acid and 30 g of the aqueous solution containing 5.0 g of potassium persulfate and 3.0 g of hydrogen peroxide were dissolved in 100 g of water. The gel-type resin was formed as the polymerization proceeded, and the microgel-type hydrogel polymer was prepared by stirring it for 30 minutes and separating the gel-type resin. The hydrogel polymer moisture content obtained was 40.1%. The polymer was spread on a stainless steel wire screen, with the orifice size of 600 pm and thickness of about 30 ml, and dried in a hot air oven at 160 ° C for 5 hours. The dry polymer was ground using a grinding machine and the base resin having a particle size of 150 pm ~ 850 pm and the fine powder with a particle diameter less than 150 pm were obtained by distributing the ground polymer with a sieve. standard according to the ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00108] The water retention capacity of the base resin obtained was 38.5 g / g, and the content of the water-soluble component was 14.6%. Preparation Example 5
[00109] After placing 500 g of acrylic acid, 2.25 g of ethoxylated trimethylolpropane triacrylate (15), and 0.165 g of diphenyl oxide (2,4,6-trimethylbenzoyl) -phosphine in a 3 L glass container equipped with an agitator, a nitrogen feeder, and a thermocouple and its dissolution, the aqueous solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5% sodium hydroxide solution to it, while the nitrogen feed continued continuously. The aqueous solution of water-soluble unsaturated monomer was cooled to 50 ° C.
[00110] After feeding 500 g of the aqueous solution to a 250 ml wide, 250 ml long and 30 ml high stainless steel container, UV polymerization was carried out by irradiating an ultraviolet ray (dosage: 10 mW / cm2) to the solution for 90 seconds and the hydrogel polymer was obtained. The moisture content measured after grinding the hydrogel polymer obtained with a size of 2 ml * 2 mm was 39.5%.
[00111] The hydrogel polymer obtained was spread on a stainless wire mesh, with the orifice size of 600 pm the thickness being about 30 mL, and dried in a hot air oven at 160 ° C for 5 hours. The dry polymer was ground using a grinding machine and the base resin having a particle size of 150 ~ 850 pm and the fine powder with a particle diameter of less than 150 pm were obtained by distributing the ground polymer with a standard sieve according to ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00112] The water retention capacity of the base resin obtained was 40.2 g / g, and the content of the water-soluble component was 11.8%. Preparation Example 6
[00113] After placing 500 g of acrylic acid, 0.45 g of 1,6-hexanediol diacrylate (HDDA), and 0.04 g of diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide in one 3 L glass container equipped with a stirrer, a nitrogen feeder, and a thermocouple and dissolving them, the aqueous solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24% sodium hydroxide solution , 5% at the same time, while nitrogen feeding continued continuously. The aqueous solution of water-soluble unsaturated monomer was cooled to 70 ° C.
[00114] After feeding 500 g of the aqueous solution to a stainless steel container 250 ml wide, 250 ml long and 30 ml high, UV polymerization was carried out by irradiating an ultraviolet ray (dosage: 10 mW / cm2) to the solution for 90 seconds and the hydrogel polymer was obtained. The moisture content measured after grinding the hydrogel polymer obtained in the size of 2 ml * 2 mm was 39.7%.
[00115] The hydrogel polymer obtained was spread on a stainless steel wire screen, with the orifice size of 600 pm being the thickness of about 30 mL, and dried in a hot air oven at 180 ° C for 5 hours. The dry polymer was ground using a grinding machine and the base resin having a particle size of 150 ~ 850 pm and the fine powder with a particle diameter of less than 150 pm were obtained by distributing the ground polymer with a sieve. standard according to the ASTM standard.
[00116] At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00117] The water retention capacity of the base resin obtained was 50.9 g / g, and the content of the water-soluble component was 16.8%. Preparation Example 7
[00118] After placing 500 g of acrylic acid, 2.25 g of ethoxylated trimethylolpropane triacrylate (15) and 0.04 g of diphenyl oxide (2,4,6-trimethylbenzoyl) -phosphine in a glass container of 3 L equipped with a stirrer, a nitrogen feeder, and a thermocouple and dissolving them, the aqueous solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5% sodium hydroxide solution same, while the nitrogen feed continued continuously. The aqueous solution of water-soluble unsaturated monomer was cooled to 70 ° C.
[00119] After feeding 500 g of the aqueous solution to a stainless steel container 250 ml wide, 250 ml long and 30 ml high, UV polymerization was carried out by irradiating an ultraviolet ray (dosage: 10 mW / cm2) to the solution for 90 seconds and the hydrogel polymer was obtained. The moisture content measured after crushing the hydrogel polymer obtained in the size of 2 ml * 2 mm was 40.1%.
[00120] The obtained hydrogel polymer was spread on a stainless wire mesh, with the orifice size of 600 pm being the thickness of about 30 ml and dried in a hot air oven at 160 ° C for 5 hours. The dry polymer was ground using a grinding machine and the base resin which has a particle size of 150 ~ 850 pm and the fine powder with a particle diameter of less than 150 pm were obtained by distributing the ground polymer with a standard sieve according to ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00121] The water retention capacity of the base resin obtained was 37.4 g / g, and the content of the water-soluble component was 7.7%. Preparation Example 8
[00122] After placing 500 g of acrylic acid, 0.675 g of 1,6-hexanediol diacrylate (HDDA), and 0.2 g of diphenyl (2,4,6-trimethylbenzoyl) -phosphine oxide in a container of 3 L glass equipped with a stirrer, a nitrogen feeder, and a thermocouple and dissolving it, the aqueous solution of the water-soluble unsaturated monomer was prepared by adding 896.4 g of 24.5 sodium hydroxide solution % still, while the nitrogen feed continued continuously. The aqueous solution of water-soluble unsaturated monomer was cooled to 50 ° C.
[00123] After feeding 500 g of the aqueous solution to a stainless steel container 250 ml wide, 250 ml long and 30 ml high, UV polymerization was carried out by irradiating an ultraviolet ray (dosage: 10 mW / cm2) to the solution for 90 seconds and the hydrogel polymer was obtained. The moisture content measured after crushing the hydrogel polymer obtained in the size of 2 ml * 2 mm was 39.8%.
[00124] The hydrogel polymer obtained was spread on a stainless wire mesh, with the orifice size of 20 600 pm being the thickness of about 30 ml, and dried in a hot air oven at 170 ° C for 5 hours . The dry polymer was ground using a grinding machine and the base resin having a particle size of 150 ~ 850 pm and the fine powder with a particle diameter of less than 150 pm was obtained by distributing the ground polymer with a sieve. standard according to the ASTM standard. At this time, the amount of fine powder obtained was 15% by weight of the dry polymer.
[00125] The water retention capacity of the base resin obtained was 39.2 g / g, and the content of the water-soluble component was 16.2%. Example 1 i) Preparation of the refurbished body of fine powder
[00126] One gram of the base resin (the second polymer) prepared in Preparation Example 2 was swollen with 100 g of water. One hundred grams of fine powder particles (the first polymer) less than 150 pm obtained in Preparation Example 1 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, in order to form the reassembled body of the fine powder . ii) Preparation of the base resin including the reassembled body
[00127] The hydrogel polymer including the reassembled body of the fine powder was prepared by introducing 200 g of the reassembled body of the fine powder prepared in step i) to the hydrogel stirring process with a kneader in Preparation Example 1 and stirring the same with the hydrogel for 1 minute. The polymer was spread on a stainless wire screen, with the orifice size of 6 00 pm being 30 mm thick and dried in a hot air oven at 170 ° C for 5 hours. The dry polymer was ground using a grinding machine and the polymer powder with a particle size of 150 ~ 850 pm was obtained by distributing the ground polymer with a standard screen according to the ASTM standard. iii) Surface reticulation reaction and preparation of the final SAP
[00128] The mixture solution of 1.0 g of ethylene carbonate, 4.0 g of water, 0.3 g of oxalic acid and 0.02 g of silica was added to 100 g of the powdered polymer obtained in the step ii) and uniformly mixed with it, and the mixture was allowed to react while drying in a hot air oven at 160 ° C for 60 minutes. The dry powder was distributed, with a standard sieve according to the ASTM standard, and the final SAP, which has a particle size of 150 ~ 850 pm, was obtained. Example 2
[00129] SAP was obtained essentially according to the same method as in Example 1, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 3 were used as the first polymer and the base resin obtained in Preparation Example 4 was used as the second polymer. Example 3 Preparation of the reassembled body from thin polymer
[00130] One gram of the base resin (the second polymer) prepared in Preparation Example 6 was swollen with 100 g of water. One hundred grams of fine powder particles (the first polymer) less than 150 pm obtained in Preparation Example 5 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder . iv) Preparation of the base resin including the reassembled body
[00131] The hydrogel polymer including the reassembled body of the fine powder was prepared by introducing 200 g of the reassembled body of the fine powder prepared in step i) for the hydrogel polymer grinding step after UV polymerization to obtain the hydrogel polymer in Preparation Example 5 and stirring it with the hydrogel for 1 minute. The polymer was spread on a stainless steel wire screen, with the orifice size of 6 00 pm being 30 mm thick and dried in a hot air oven at 170 ° C for 5 hours. The dry polymer was ground using a grinding machine and the polymer powder with a particle size of 150 ~ 850 pm was obtained by distributing the ground polymer with a standard screen according to the ASTM standard. v) i) Surface reticulation reaction and preparation of the final SAP
[00132] The mixture solution of 1.0 g of ethylene carbonate, 4.0 g of water, 0.3 g of oxalic acid and 0.02 g of silica was added to 100 g of the powdered polymer obtained in the step ii) and uniformly mixed with it, and the mixture was allowed to react while drying in a hot air oven at 160 ° C for 60 minutes. The dry powder was distributed, with a standard sieve according to the ASTM standard, and the final SAP, which has a particle size of 150 ~ 850 pm, was obtained. Example 4
[00133] SAP was obtained essentially according to the same method as in Example 3, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 7 were used as the first polymer and the base resin obtained in Preparation Example 8 was used as the second polymer. Example 5
[00134] SAP was obtained essentially according to the same method as in Example 1, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 1 were used as the first polymer and the base resin obtained in Preparation Example 6 was used as the second polymer. Example 6
[00135] SAP was obtained essentially according to the same method as in Example 3, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 5 were used as the first polymer and the base resin obtained in Preparation Example 2 was used as the second polymer. Example 7
[00136] SAP was obtained essentially according to the same method as in Example 1, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 3 were used as the first polymer and the base resin obtained in Preparation Example 1 was used as the second polymer. Example 8
[00137] SAP was obtained essentially according to the same method as in Example 3, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 7 were used as the first polymer and the base resin obtained in Preparation Example 5 was used as the second polymer. Example 9
[00138] SAP was obtained essentially according to the same method as in Example 1, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 4 were used as the first polymer and the base resin obtained in Preparation Example 2 was used as the second polymer. Example 10
[00139] SAP was obtained essentially according to the same method as in Example 3, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 8 were used as the first polymer and the base resin obtained in Preparation Example 6 was used as the second polymer. Comparative Example 1
[00140] SAP was obtained essentially according to the same method as in Example 1, except that the refitted body of the fine powder was prepared by mixing 100 g of fine powder particles less than 15 pm obtained in the Preparation Example 1 and 100 g of water with a high speed rotating stirrer in the preparation stage of the body reassembled from fine powder. Comparative Example 2
[00141] SAP was obtained essentially according to the same method as in Example 2, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 15 pm obtained in the Preparation Example 3 and 100 g of water, with a high speed rotating shaker in the stage of preparing the body reassembled from fine powder. Comparative Example 3
[00142] SAP was obtained essentially according to the same method as in Example 3, except that the reassembled body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in Preparation Example 5 and 100 g of water with a high speed rotating shaker in the stage of preparing the body reassembled from fine powder. Comparative Example 4
[00143] SAP was obtained essentially according to the same method as in Example 4, except that the refitted body of the fine powder was prepared by mixing 100 g of fine powder particles less than 150 pm obtained in Preparation Example 7 and 100 g of water, with a high speed rotating shaker in the stage of preparing the body reassembled from fine powder. Comparative Example 5
[00144] SAP was obtained essentially according to the same method as in Example 1, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 1 were used as the first polymer and the resin powder obtained in Preparation Example 3 was used as the second polymer. Comparative Example 6
[00145] SAP was obtained essentially according to the same method as in Example 3, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 5, were used as the first polymer and the resin powder obtained in Preparation Example 7 it was used as the second polymer.
[00146] The SAP properties of Examples 1 to 10 and Comparative Examples 1 to 6 were measured and the results are listed in Table 1 below. Table 1


(* Fine powder content less than 150 pm (%): result of the ball mill test)
[00147] With reference to Table 1, the SAPs prepared by the method of the present invention are superior in water holding capacity, absorptive power under pressure, and penetrability without reference to the polymerization initiation method. However, it is recognized that the SAPs of Comparative Examples 5 and 6, the water-holding capacity of which and the water-soluble component of the second polymer were higher than the first polymer showed higher content of fine powder and less penetration, in comparison with examples 1 and 3.
[00148] And, as a result, in the ball mill test, it is recognized that the particles of a fine powder less than 150 pm are apparently less in the SAPs prepared by the examples of the present invention. The fine powder can be formed by the friction between the SAP particles during the SAP transfer processes or the preparation of a product in which the SAP is included, and the properties of the SAP included in the product may be less than the properties measured only after SAP has been prepared. However, referring to the ball mill test, it is recognizable that re-insulation of the SAP due to friction during the product preparation process rarely occurs in the SAPs prepared by Examples 5 of the present invention. Example 11 i) Preparation of the reassembled body from fine powder
[00149] One gram of base resin (second polymer) prepared by Preparation Example 2 was swollen with 100 g of water. One hundred grams of fine powder particles of the polymer (the first polymer) less than 150 pm obtained in Preparation Example 1 and 100 g of the second swollen polymer were mixed using a high speed rotating agitator to form the reassembled body of the thin powder. ii) Preparation of the base resin, including the reassembled body
[00150] After mixing 200 g of the reassembled body of the fine powder prepared in step i) with the hydrogel polymer obtained in the process of preparing the base resin of Preparation Example 1, in a simple way, the mixed polymer was spread over a stainless wire mesh, with an orifice size of 600 pm, thickness of about 30 mm, and dried in a hot air oven at 170 pm for 5 hours. The dry polymer was ground using a grinding apparatus and the polymer powder with a particle size of 150 ~ 850 pm was obtained by distributing the ground polymer with a standard screen according to the ASTM standard. iii) Surface reticulation reaction and preparation of the final SAP
[00151] The mixture solution of 1.0 g of ethylene carbonate, 4.0 g of water, 0.3 g of oxalic acid, and 0.02 g of silica was added to 100 g of the powdered polymer obtained in the step ii) and uniformly mixed with it, and the mixture was allowed to react when dried in a hot air oven at 160 ° C for 60 minutes. The dry powder was distributed, with a standard sieve according to the ASTM standard, and the final SAP, having a particle size of 150 ~ 850 pm was obtained. Example 12
[00152] SAP was obtained essentially according to the same method as in Example 11, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 3 were used as the first polymer and the resin of base obtained in Preparation Example 4 was used as the second polymer. Example 13 i) Preparation of the reassembled body from fine powder
[00153] After swelling of 1 g of the base resin (second polymer), prepared by Preparation Example 6 with 100 g of water, 100 g of fine powder particles (first polymer), with less than 150 pm obtained in the Example of Preparation 5 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer to form the reassembled body of the fine powder. ii) Preparation of the base resin including the reassembled body
[00154] After mixing 200 g of the reassembled body of the fine powder prepared in step i), with the hydrogel polymer in a size of 2 mL * 2 mm in Preparation Example 5, in a simple way, the mixed polymer was spread over a stainless steel mesh having an orifice size of 600 pm and a thickness of about 30 mm, and dried in a hot air oven at 170 ° C for 5 hours. The dry polymer was ground using a milling machine and the powdered polymer having a particle size of 150 ~ 850 pm was obtained by distributing the ground polymer with a standard screen according to the ASTM standard. iii) Surface reticulation reaction and preparation of the final SAP
[00155] The mixture solution of 1.0 g of ethylene carbonate, 4.0 g of water, 0.3 g of oxalic acid, and 0.02 g of silica was added to 100 g of the powdered polymer obtained in step ii) and uniformly mixed with it, and the mixture was allowed to react when dried in a hot air oven at 160 ° C for 60 minutes. The dry powder was distributed, with a standard sieve according to the ASTM standard, and the final SAP, which has a particle size of 150 ~ 850 pm, was obtained. Example 14
[00156] SAP was obtained essentially according to the same method as in Example 13 with the exception that particles of a fine powder less than 150 pm obtained in Preparation Example 7 were used as the first polymer and the base resin obtained in Preparation Example iv) was used as the second polymer. Comparative example 7
[00157] SAP was obtained essentially according to the same method as in Example 11, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in the Preparation Example 1 and 100 g of water, with a high speed rotating shaker in the preparation stage of the reassembled body of the fine powder. Comparative Example 8
[00158] SAP was obtained essentially according to the same method as in Example 12, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in the Preparation of Example 3 and 100 g of water, with a high speed rotating shaker in the stage of preparing the body reassembled from fine powder. Comparative Example 9
[00159] SAP was obtained essentially according to the same method as in Example 13, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in the Preparation Example 5 and 100 g of water with a high speed rotating shaker in the stage of preparing the body reassembled from fine powder. Comparative Example 10
[00160] SAP was obtained essentially according to the same method as in Example 14, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 15 pm obtained in the Preparation Example 7 and 100 g of water, with a high speed rotating shaker in the body preparation stage, reassembled from fine powder.
[00161] The SAP properties of Examples 11 to 14 and Comparative Examples 7 to 10 were measured and the results are listed in Table 2 below. Table 2

(* Fine powder content less than 150 pm (%): result of the ball mill test)
[00162] Referring to Table 2, it is recognizable that there was no decrease in the water retention capacity and penetrability, even in the case of the formation of SAP, just by mixing the refitted body of the fine powder and the first hydrogel polymer without mechanical stirring as in Examples 11 to 14. Example 15 i) Preparation of the reassembled body from fine powder
[00163] After swelling of 2 g of the microgel-type hydrogel polymer (second polymer), obtained in the middle step of Preparation Example 2 with 100 g of water, 100 g of particles of a fine powder (first polymer), with less 150 pm obtained in Preparation Example 1 and 100 g of the second swollen polymer were mixed using a high speed rotating agitator to form the reassembled body of the fine powder. ii) Preparation of the base resin including the reassembled body
[00164] After mixing 200 g of the reassembled body of the fine powder prepared in step i), with the hydrogel polymer of the microgel type obtained in the process of preparing the base resin of Preparation Example 1, in a simple way, the polymer mixed it was spread over a stainless steel mesh having an orifice size of 600 pm and a thickness of about 30 mm, and dried in a hot air oven at 170 ° C for 5 hours. The dry polymer was ground using a milling machine and the powdered polymer having a particle size of 150 ~ 850 pm was obtained by distributing the ground polymer with a standard screen according to the ASTM standard. iii) Surface reticulation reaction and preparation of the final SAP
[00165] The mixture solution of 1.0 g of ethylene carbonate, 4.0 g of water, 0.3 g of oxalic acid, and 0.02 g of silica was added to 100 g of the powdered polymer obtained in the step ii) and uniformly mixed with it, and the mixture was allowed to react when dried in a hot air oven at 160 ° C for 60 minutes. The dry powder was distributed, with a standard sieve according to the ASTM standard, and the final SAP, which has a particle size of 150 ~ 850 pm, was obtained. Example 16
[00166] SAP was obtained essentially according to the same method as in Example 15, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 3 were used as the first polymer and the polymer of microgel-type hydrogel obtained in the middle step of Preparation Example 4 was used as the second polymer. Example 17 i) Preparing the reassembled body from fine powder
[00167] After swelling of 2 g of the microgel-type hydrogel polymer (second polymer), obtained in the middle step of Preparation Example 6 with 100 g of water, 100 g of particles of a fine powder (first polymer), with less 150 pm obtained in Preparation Example 5 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer to form the reassembled body of the fine powder. ii) Preparation of the base resin including the reassembled body
[00168] After mixing 200 g of the reassembled body of the fine powder prepared in step i), with the hydrogel polymer crushed to a size of 2 mm * 2 mm in Preparation Example 5, in a simple way, the mixed polymer was spread on a stainless steel mesh having an orifice size of 600 pm and a thickness of about 30 mm, and dried in a hot air oven at 170 ° C for 5 hours. The dry polymer was ground using a milling machine and the powdered polymer having a particle size of 150 ~ 850 pm was obtained by distributing the ground polymer with a standard screen according to the ASTM standard. iii) Surface reticulation reaction and preparation of the final SAP
[00169] The mixture solution of 1.0 g of ethylene carbonate, 4.0 g of water, 0.3 g of oxalic acid, and 0.02 g of silica was added to 100 g of the powdered polymer obtained in step ii) and uniformly mixed with it, and the mixture was allowed to react when dried in a hot air oven at 160 ° C for 60 minutes. The dry powder was distributed, with a standard sieve according to the ASTM standard, and the final SAP, which has a particle size of 150 ~ 850 pm, was obtained. Example 18
[00170] SAP was obtained essentially according to the same method as in Example 17, except that the particles of a fine powder less than 150 pm obtained in Preparation Example 7 were used as the first polymer and the polymer of microgel-type hydrogel obtained in the middle step of Preparation Example 8 was used as the second polymer.
[00171] The SAP properties of Examples 15 to 18 were measured and the results are listed in Table 3 below. Table 3

(* Fine powder content less than 150 pm (%): result of the ball mill test)
[00172] With reference to Table 3, it is recognized that the present invention was effective, even if the hydrogel polymer before drying after polymerization, which was not in the powder phase, was used as the second polymer after being swelled. . Example 19
[00173] The final SAP was obtained substantially according to the same method as in Example 1, except that 5 g of the base resin (second polymer) prepared by Preparation Example 2 were swollen with 100 g of water and 100 g of fine powder particles (first polymer), less than 150 µm obtained in Preparation Example 1 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder. Example 20
[00174] The final SAP was obtained substantially according to the same method as in Example 1, except that 10 g of the base resin (second polymer) prepared by Preparation Example 2 were swollen with 100 g of water and 100 g of fine powder particles (first polymer), less than 150 µm obtained in Preparation Example 1 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder. Example 21
[00175] The final SAP was obtained substantially according to the same method as in Example 1, except that 20 g of the base resin (second polymer) prepared by Preparation Example 2 were swollen with 100 g of water and 100 g of fine powder particles (first polymer), less than 150 µm obtained in Preparation Example 1 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder. Example 22
[00176] The final SAP was obtained substantially according to the same method as in Example 2, except that 1 g of the base resin (second polymer) prepared by Preparation Example 4 was swollen with 50 g of water and 100 g of fine powder particles (first polymer), less than 150 µm obtained in Preparation Example 3 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder. Example 23
[00177] The final SAP was obtained substantially according to the same method as in Example 2, except that 1 g of the base resin (second polymer) prepared by Preparation Example 4 was swollen with 150 g of water and 100 g of fine powder particles (first polymer), less than 150 µm obtained in Preparation Example 3 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder. Example 24
[00178] The final SAP was obtained essentially according to the same method as in Example 2, except that 1 g of the base resin (second polymer), prepared by Preparation Example 4 was swollen with 200 g of water, and 100 g of fine powder particles (first polymer), less than 150 pm obtained in Preparation Example 3 and 100 g of the second swollen polymer were mixed using a high speed rotating stirrer, to form the reassembled body of the fine powder. Comparative Example 11
[00179] The final SAP was obtained essentially according to the same method as in Example 2, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in the Example of Preparation 3 and 50 g of water, with a high speed rotating shaker in the stage of preparing the reassembled body of the fine powder. Comparative Example 12
[00180] The final SAP was obtained essentially according to the same method as in Example 2, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in the Preparation Example 3 and 150 g of water, with a high speed stirrer in the preparation stage of the body reassembled from fine powder. Comparative Example 13
[00181] The final SAP was obtained essentially according to the same method as in Example 2, except that the refitted body of the fine powder was prepared by mixing 100 g of particles of a fine powder with less than 150 pm obtained in the Preparation Example 3 and 200 g of water, with a high speed rotating shaker in the preparation stage of the body reassembled from fine powder.
[00182] The SAP properties of Examples 19 to 24 and Comparative Examples 11 to 13 were measured and the results are listed in Table 4 below. Table 4

(* Fine powder content less than 150 pm (%): result of the ball mill test)
[00183] In general, the aggregation force of fine powders is high when a large amount of water is used in the preparation of the body reassembled from fine powder. However, with reference to Table 4, there is not much difference in the aggregation strength according to the variation in the amount of water used in the preparation method of the present invention. This is due not only to the water, but also to the hydrogel polymer used as the second polymer in the refitting step of fine powders, the hydrogel polymer plays a binder role and water is evenly distributed among the fine powder particles, so that the reassembled body of uniform fine powder is formed.

权利要求:
Claims (8)
[0001]
1. Method of preparing a superabsorbent polymer characterized by including the steps of: preparing a first hydrogel polymer by carrying out thermal polymerization or photo polymerisation of a monomeric composition including an unsaturated ethylene-based monomer, soluble in water and a polymerization initiator; preparing a second hydrogel polymer by performing thermal polymerization or photo polymerization of a monomeric composition including an ethylene-based, water-soluble unsaturated monomer and a polymerization initiator; drying and grinding the first hydrogel polymer and distributing the first hydrogel polymer into a fine powder with a particle diameter below 150 pm and a base resin having a particle diameter from 150 pm to 850 pm; fabricating a refitted body of the fine powder by mixing the fine powder and the second hydrogel polymer; and mixing the reassembled body of the fine powder with the first hydrogel polymer, and drying and grinding the reassembled body of the fine powder and mixed with the first hydrogel polymer, in which the second hydrogel polymer has a greater water retention capacity than the first hydrogel polymer, wherein the content of the fine powder whose particle diameter is below 150 pm is 3% by weight or less in the super absorbent polymer.
[0002]
2. Method according to claim 1, characterized by the fact that the first hydrogel polymer has a water holding capacity of 30 to 50 g / g and the second hydrogel polymer has a water holding capacity of 35 to 60 g g / g.
[0003]
Method according to claim 1, characterized by the fact that the second hydrogel polymer has a water-soluble component content greater than the first hydrogel polymer.
[0004]
4. Method according to claim 3, characterized in that the content of the water-soluble component of the first hydrogel polymer is 5 to 30% by weight and the content of the water-soluble component of the second hydrogel polymer is from 6 to 35% by weight.
[0005]
5. Method according to claim 1, characterized by the fact that the second hydrogel polymer is in a water-free swelling state.
[0006]
6. Method according to claim 5, characterized in that the second hydrogel polymer is free of swelling with water, so as to contain 50 to 50,000% by weight of water, based on the weight of the second polymer.
[0007]
7. Method, according to claim 1, characterized by the fact that the step of manufacturing the reassembled body of the fine powder is carried out by mixing 10 to 200 parts by weight of the second hydrogel polymer with 100 parts by weight of the powder thin.
[0008]
8. Method according to claim 1, characterized by the fact that it additionally includes a step of cross-linking the surface, after the step of drying and grinding the reassembled body of the fine powder and the first hydrogel polymer.

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同族专利:

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公开号 | 公开日

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BR112014015719A8|2017-07-04|

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WO2014077612A1|2014-05-22|

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US9156974B2|2015-10-13|

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BR112014015719A2|2017-06-13|

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KR20140063457A|2014-05-27|

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US20150259522A1|2015-09-17|

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CN104144973B|2016-04-06|

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CN104144973A|2014-11-12|

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KR101559081B1|2015-10-08|

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EP2787025B1|2018-01-10|

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EP2787025A1|2014-10-08|

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EP2787025A4|2015-12-02|

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法律状态:
2019-10-15| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

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2020-09-15| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

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2020-10-27| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 15/11/2013, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

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申请号 | 申请日 | 专利标题

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KR20120129559|2012-11-15|

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KR10-2012-0129559|2012-11-15|

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KR1020130138510A|KR101559081B1|2012-11-15|2013-11-14|Preparation method for super absorbent polymer and super absorbent polymer prepared therefrom|

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KR10-2013-0138510|2013-11-14|

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PCT/KR2013/010380|WO2014077612A1|2012-11-15|2013-11-15|Method for preparing super absorbent resin, and super absorbent resin prepared by same|

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