Title of Invention: Super absorbent polymer composition and manufacturing method thereof
technical field
[One]
Cross-Citation with Related Application(s)
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0120645 on September 30, 2019 and Korean Patent Application No. 10-2020-0087106 on July 14, 2020, All content disclosed in the literature is incorporated as a part of this specification.
[3]
[4]
The present invention relates to a superabsorbent polymer composition and a method for preparing the same. More specifically, the present invention relates to a superabsorbent polymer composition having improved anti-caking efficiency without deterioration in absorption performance and a method for preparing the same.
background
[5]
Super Absorbent Polymer (SAP) is a synthetic polymer material that can absorb water 500 to 1,000 times its own weight. Material), etc., are named differently. The superabsorbent polymer as described above started to be put to practical use as a sanitary tool, and is now widely used as a soil repair agent for horticulture, water-retaining material for civil engineering and construction, sheets for seedlings, freshness maintenance agent in the food distribution field, and materials for poultice. .
[6]
Such superabsorbent polymers are mainly used in the field of sanitary materials such as diapers and sanitary napkins. In the sanitary material, the superabsorbent polymer is generally included in a state spread in the pulp. However, in recent years, efforts have been made to provide sanitary materials such as diapers having a thinner thickness, and as a part of that, the content of pulp is reduced or, further, so-called pulpless diapers, etc. in which no pulp is used at all Development is actively underway.
[7]
As such, in the case of a sanitary material in which the content of pulp is reduced or in which pulp is not used, the superabsorbent polymer is included in a relatively high ratio, so that the superabsorbent polymer particles are inevitably included in multiple layers in the sanitary material. In order for the entire superabsorbent polymer particles included in the multi-layered structure to more efficiently absorb a large amount of liquid such as urine, the superabsorbent polymer should basically exhibit high absorption performance.
[8]
On the other hand, such a superabsorbent polymer contains a number of hydrophilic parts on its surface to exhibit high absorption properties for liquids, specifically water, and because of these hydrophilic parts, it absorbs moisture contained in air when exposed to air. Aggregation and caking between the superabsorbent polymer particles have occurred.
[9]
Accordingly, in order to prevent aggregation and caking between the superabsorbent polymer particles, the addition of an anti-caking agent has been considered, but the absorption performance of the superabsorbent polymer is poor when the anti-caking agent is used. There was a problem with degradation.
[10]
Accordingly, there is a continuous demand for the development of a superabsorbent polymer technology that prevents caking between the superabsorbent polymer particles and does not deteriorate the absorbent performance.
[11]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[12]
Accordingly, the present invention relates to a superabsorbent polymer composition having improved anti-caking efficiency without deterioration of absorption performance by simultaneously including a first hydrophobic material and a second hydrophobic material having a specific structure.
[13]
In addition, according to the present invention, hydrophobicity is imparted to a part of the surface of the prepared superabsorbent polymer particles by pulverizing with the hydrophobic composition after preparing the hydrogel polymer, so that the caking phenomenon can be prevented, and the hydrophobic composition has a difference in hydrophobicity. An object of the present invention is to provide a method for manufacturing a super absorbent polymer in which a decrease in absorption performance is prevented by including a hydrophobic material of the species.
[14]
means of solving the problem
[15]
In order to solve the above problems, the present invention,
[16]
superabsorbent polymer particles comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acidic group;
[17]
a first hydrophobic material; and
[18]
Provided is a superabsorbent polymer composition including a second hydrophobic material.
[19]
In this case, the first hydrophobic material includes a carboxylic acid or a salt thereof represented by the following Chemical Formula 1, and the second hydrophobic material includes a carboxylic acid or a salt thereof represented by the following Chemical Formula 2:
[20]
[Formula 1]
[21]

[22]
In Formula 1,
[23]
x is an integer from 10 to 20,
[24]
[Formula 2]
[25]

[26]
In Formula 2,
[27]
y is an integer from 5 to 15;
[28]
z is an integer from 1 to 10;
[29]
[30]
In addition, the present invention provides a method for preparing a super absorbent polymer composition comprising:
[31]
forming a hydrogel polymer by crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized in the presence of an internal crosslinking agent and a polymerization initiator;
[32]
preparing a pulverized product including water-containing superabsorbent polymer particles and the hydrophobic composition by adding the hydrophobic composition comprising the first hydrophobic material and the second hydrophobic material to the hydrogel polymer and pulverizing the hydrophobic composition; and
[33]
Drying the pulverized material to prepare a superabsorbent polymer composition including superabsorbent polymer particles, the first hydrophobic material, and the second hydrophobic material.
[34]
Effects of the Invention
[35]
According to the superabsorbent polymer composition of the present invention, caking prevention efficiency can be improved without deterioration of absorption performance.
[36]
In addition, according to the method for manufacturing the superabsorbent polymer of the present invention, when the water content polymer is pulverized in a state in which a hydrophobic composition including two types of hydrophobic materials having different hydrophobic properties is added, agglomeration between the manufactured superabsorbent polymer particles does not occur. Thus, caking can be prevented even in high-temperature and high-humidity environments.
[37]
Modes for carrying out the invention
[38]
The terminology used herein is used to describe exemplary embodiments only, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as "comprise", "comprising" or "having" are intended to designate that an embodied feature, step, element, or a combination thereof is present, and includes one or more other features or steps; It should be understood that the possibility of the presence or addition of components, or combinations thereof, is not precluded in advance.
[39]
Since the present invention may have various changes and may have various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.
[40]
Since the present invention may have various changes and may have various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.
[41]
Hereinafter, a method for manufacturing a super absorbent polymer and a super absorbent polymer according to specific embodiments of the present invention will be described in more detail.
[42]
Before that, the terminology used herein is for the purpose of referring to particular embodiments only, and is not intended to limit the present invention. And, as used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite.
[43]
[44]
According to one embodiment of the invention, the superabsorbent polymer particles comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer having at least a part of the neutralized acidic group; a first hydrophobic material; And there is provided a superabsorbent polymer composition comprising a second hydrophobic material.
[45]
In this case, the first hydrophobic material includes a carboxylic acid or a salt thereof represented by the following Chemical Formula 1, and the second hydrophobic material includes a carboxylic acid or a salt thereof represented by the following Chemical Formula 2:
[46]
[Formula 1]
[47]

[48]
In Formula 1,
[49]
x is an integer from 10 to 20,
[50]
[Formula 2]
[51]

[52]
In Formula 2,
[53]
y is an integer from 5 to 15;
[54]
z is an integer from 1 to 10;
[55]
[56]
In addition, according to another embodiment of the invention, in the presence of an internal crosslinking agent and a polymerization initiator, the method comprising the steps of crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized to form a hydrogel polymer; preparing a pulverized product including water-containing superabsorbent polymer particles and the hydrophobic composition by adding a hydrophobic composition including a first hydrophobic material and a second hydrophobic material to the water-containing gel polymer and pulverizing the hydrophobic composition; and drying the pulverized material to prepare a superabsorbent polymer composition including the superabsorbent polymer particles, the first hydrophobic material, and the second hydrophobic material.
[57]
[58]
As used herein, the term “polymer” or “polymer” refers to a polymerized state of a water-soluble ethylenically unsaturated monomer, and may cover all water content ranges or particle diameter ranges. Among the above polymers, a polymer having a water content (moisture content) of about 30% by weight or more in a state before drying after polymerization may be referred to as a hydrogel polymer, and particles obtained by pulverizing and drying the hydrogel polymer may be referred to as a crosslinked polymer. have.
[59]
In addition, the term "superabsorbent polymer particles" refers to a particulate material comprising an acidic group and a crosslinked polymer in which a water-soluble ethylenically unsaturated monomer in which at least a portion of the acidic group is neutralized is polymerized and crosslinked by an internal crosslinking agent.
[60]
In addition, the term "super absorbent polymer" refers to a crosslinked polymer obtained by polymerizing a water-soluble ethylenically unsaturated monomer containing an acidic group and neutralizing at least a portion of the acidic group, or powder consisting of particles of a superabsorbent polymer obtained by pulverizing the crosslinked polymer, depending on the context. It means a base resin in the form of (powder), or the crosslinked polymer or the base resin is subjected to additional processes, such as surface crosslinking, fine powder reassembly, drying, pulverization, classification, etc., to a state suitable for commercialization. used to be all-inclusive. Accordingly, the term “super absorbent polymer composition” may be interpreted as including a composition including a super absorbent polymer, that is, a plurality of super absorbent polymer particles.
[61]
[62]
In general, the superabsorbent polymer, which is a cross-linked polymer prepared by polymerization of a water-soluble ethylenically unsaturated monomer in the presence of an internal cross-linking agent, has an acidic group (-COOH) and/or a neutralized acid group (-COO- ) remaining unpolymerized . This makes the surface hydrophilic. Due to the hydrophilicity of the surface of the superabsorbent polymer, it absorbs moisture in the air when exposed to air, and capillary force, hydrogen bonding, inter-particular diffusion, or inter-particular diffusion caused by water existing between the superabsorbent polymer particles. There has been a problem in that van der Waals forces and the like are generated, and irreversible agglomeration between particles occurs. In addition, water is necessarily used during the manufacturing process of the superabsorbent polymer, and there is a problem as described above.
[63]
Accordingly, the present inventors have found that when two types of hydrophobic materials having different hydrophobic properties are added and pulverized together after preparing the hydrogel polymer, hydrophobicity is imparted to a part of the surface of the prepared superabsorbent polymer particles, so that the caking phenomenon can only be prevented. Rather, it was confirmed that, due to the hydrophobic materials exhibiting different hydrophobic properties, deterioration of absorption performance can be prevented, thereby completing the present invention.
[64]
Specifically, the first hydrophobic material represented by Formula 1 and the second hydrophobic material represented by Formula 2 are both a hydrophobic functional group by a linear alkyl group and a hydrophilic functional group by a carboxyl group. have at the same time Therefore, when they are pulverized together with the water content polymer, the hydrophilic functional group of the hydrophobic material is adsorbed to the hydrophilic portion existing on the surface of the superabsorbent polymer particles, and the surface of the particle to which the hydrophobic material is adsorbed is a linear alkyl group of the hydrophobic material hydrophobicity by Accordingly, even when the superabsorbent polymer is exposed to the air, a portion of the superabsorbent polymer particles becomes hydrophobic, and irreversible aggregation between the particles can be suppressed.
[65]
In addition, unlike the first hydrophobic material, the second hydrophobic material further includes one or more ethylene oxide linkages between the linear alkyl group and the carboxyl group present at both terminals, thereby exhibiting lower hydrophobicity than the first hydrophobic material. Accordingly, when the first hydrophobic material and the second hydrophobic material are used together in manufacturing the superabsorbent polymer, it is possible to manufacture the superabsorbent polymer with improved anti-caking efficiency without deterioration in absorption performance. On the other hand, when only the first hydrophobic material is used, there may be a problem of a decrease in absorption performance due to imparting strong hydrophobicity, and when only the second hydrophobic material is used, suppression of the caking phenomenon may not be effectively achieved .
[66]
[67]
Super absorbent resin composition
[68]
Hereinafter, the superabsorbent polymer composition of one embodiment will be described in more detail for each component.
[69]
The superabsorbent polymer composition according to one embodiment includes a plurality of superabsorbent polymer particles including a cross-linked polymer of a water-soluble ethylenically unsaturated monomer having at least partially neutralized acid groups. In this case, the cross-linked polymer is a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acid group cross-linked in the presence of an internal cross-linking agent, and the main chains formed by polymerization of the monomers are cross-linked by the internal cross-linking agent. It has a three-dimensional network structure.
[70]
The water-soluble ethylenically unsaturated monomer may be any monomer commonly used in the preparation of super absorbent polymers. As a non-limiting example, the water-soluble ethylenically unsaturated monomer may be a compound represented by the following Chemical Formula 2:
[71]
[Formula 2]
[72]
R 1 -COOM 2
[73]
In Formula 2,
[74]
R 1 is an alkyl group having 2 to 5 carbon atoms including an unsaturated bond,
[75]
M 2 is a hydrogen atom, a monovalent or divalent metal, an ammonium group, or an organic amine salt.
[76]
Preferably, the monomer may be at least one selected from the group consisting of (meth)acrylic acid and monovalent (alkali) metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids.
[77]
As such, when (meth)acrylic acid and/or a salt thereof is used as the water-soluble ethylenically unsaturated monomer, it is advantageous because a superabsorbent polymer with improved water absorption can be obtained. In addition, the monomer includes maleic anhydride, fumaric acid, crotonic acid, itaconic acid, 2-acryloylethane sulfonic acid, 2-methacryloylethanesulfonic acid, 2-(meth)acryloylpropanesulfonic acid, or 2-(meth) ) acrylamide-2-methyl propane sulfonic acid, (meth)acrylamide, N-substituted (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, methoxypolyethylene Glycol (meth)acrylate, polyethylene glycol (meth)acrylate, (N,N)-dimethylaminoethyl (meth)acrylate, (N,N)-dimethylaminopropyl (meth)acrylamide and the like can be used.
[78]
Here, the water-soluble ethylenically unsaturated monomer may have an acidic group, and at least a portion of the acidic group may be neutralized by a neutralizing agent. Specifically, in the mixing of the water-soluble ethylenically unsaturated monomer having an acidic group, the internal crosslinking agent, the polymerization initiator, and the neutralizing agent, at least a portion of the acidic groups of the water-soluble ethylenically unsaturated monomer may be neutralized. In this case, as the neutralizing agent, a basic material such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, etc. that can neutralize an acidic group may be used.
[79]
In addition, the degree of neutralization of the water-soluble ethylenically unsaturated monomer, which refers to the degree of neutralization by the neutralizing agent among the acidic groups included in the water-soluble ethylenically unsaturated monomer, is 50 to 90 mol%, or, 60 to 85 mol%, or 65 to 85 mole %, or 65 to 75 mole %. 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 is precipitated and it may be difficult for polymerization to proceed smoothly. It can exhibit properties like elastic rubber, which is difficult to handle.
[80]
In addition, the term 'internal crosslinking agent' used in this specification is a term used to distinguish it from a surface crosslinking agent for crosslinking the surface of the superabsorbent polymer particles to be described later. serves to make The crosslinking in the above step proceeds without a surface or internal division, but when the surface crosslinking process of the superabsorbent polymer particles to be described later proceeds, the surface of the particles of the superabsorbent polymer finally produced has a structure crosslinked by a surface crosslinking agent, The inside has a structure crosslinked by the internal crosslinking agent.
[81]
As the internal crosslinking agent, any compound may be used as long as it enables the introduction of crosslinking during polymerization of the water-soluble ethylenically unsaturated monomer. As a non-limiting example, the internal crosslinking agent is N,N'-methylenebisacrylamide, trimethylolpropane tri(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol (meth)acrylate, propylene glycol di( Meth) acrylate, polypropylene glycol (meth) acrylate, butanediol di (meth) acrylate, butylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, hexanediol di (meth) ) acrylate, triethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, dipentaerythritol pentaacrylate, glycerin tri(meth)acrylate, penta A polyfunctional crosslinking agent such as erythol tetraacrylate, triarylamine, ethylene glycol diglycidyl ether, propylene glycol, glycerin, or ethylene carbonate may be used alone or in combination of two or more, but is not limited thereto. Preferably, among them, ethylene glycol diglycidyl ether may be used.
[82]
The crosslinking polymerization of the water-soluble ethylenically unsaturated monomer in the presence of such an internal crosslinking agent may be carried out by thermal polymerization, photopolymerization or hybrid polymerization in the presence of a polymerization initiator, optionally a thickener, plasticizer, storage stabilizer, antioxidant, etc. There, the specific details will be described later.
[83]
The superabsorbent polymer particles may have a particle diameter of about 150 to about 850 μm, and this particle diameter may be measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 220.3 method.
[84]
[85]
In addition, the superabsorbent polymer composition includes the first hydrophobic material represented by Chemical Formula 1 and the second hydrophobic material in addition to the superabsorbent polymer particles. As described above, the first hydrophobic material and the second hydrophobic material may be mixed in a pulverization process of the hydrogel polymer after polymerization rather than a polymerization process, and may be uniformly applied to the surface of the superabsorbent polymer particles.
[86]
[87]
First, the first hydrophobic material includes a carboxylic acid represented by Formula 1 or a salt thereof. Alternatively, the first hydrophobic material is a carboxylic acid represented by Formula 1 or a salt thereof.
[88]
In Chemical Formula 1, the hydrophobic portion is a linear alkyl group having x+2 carbon atoms, where when x is less than 10, there is a problem that sufficient hydrophobicity is not imparted to the surface of the particles of the superabsorbent polymer, and when x is more than 20 , there is a problem that the molecular length of the material is too long and may not be effectively applied to the hydrogel polymer. More specifically, it may be 11 or more, 13 or more, or 14 or more, and 18 or less, 17 or less, or 16 or less. For example, x may be an integer from 11 to 15.
[89]
In addition, the first hydrophobic material includes a salt thereof other than the carboxylic acid represented by Formula 1, specifically, in this case, the carboxylate may be a monovalent metal salt, a divalent metal salt, or an ammonium salt. More specifically, the carboxylate may be an alkali metal salt such as a sodium salt or a potassium salt.
[90]
As the first hydrophobic material, stearic acid, myristic acid, palmitic acid, or alkali metal salts thereof may be used.
[91]
[92]
On the other hand, in Formula 2, the hydrophobic portion is a linear alkyl group having y+1 carbon atoms, where y is less than 5, as in the first hydrophobic material, it does not provide sufficient hydrophobicity to the surface of the particles of the superabsorbent polymer. There is a problem, and when y is greater than 15, the molecular length of the material becomes too long, and there is a problem that it may not be effectively applied to the hydrogel polymer. More specifically, y may be 9 or more, or 10 or more, and 13 or less, or 12 or less. For example, y may be 11.
[93]
In addition, when z, which means the number of ethylene oxide linkages in Formula 2, is 0, there is no difference in hydrophobic properties from the first hydrophobic material, so the absorption rate of the superabsorbent polymer may decrease, and when z exceeds 11 Since it is difficult to impart hydrophobic properties to the superabsorbent polymer, it may be difficult to suppress the occurrence of caking between particles. More specifically, z may be 2 or more, 3 or more, or 4 or more, and 10 or less. For example, z may be an integer from 5 to 10.
[94]
In this case, the second hydrophobic material includes a salt thereof other than the carboxylic acid represented by Chemical Formula 2, wherein the description of the salt refers to the description of the first hydrophobic material.
[95]
As such a second hydrophobic material, laureth-6 carboxylic acid, laureth-7 carboxylic acid, laureth-8 carboxylic acid acid), laureth-9 carboxylic acid, laureth-10 carboxylic acid, laureth-11 carboxylic acid, or these of alkali metal salts can be used.
[96]
[97]
In addition, the first hydrophobic material may be in a solid state at 25 ℃. That is, the first hydrophobic material may be in a solid state at room temperature because the melting point is higher than 25°C. In addition, the second hydrophobic material may be in a liquid state at 25°C. That is, the second hydrophobic material has a melting point lower than 25° C. and may be in a liquid state at room temperature.
[98]
[99]
In this case, the total weight of the first hydrophobic material and the second hydrophobic material may be included in an amount of 0.01 to 1.0 parts by weight based on 100 parts by weight of the superabsorbent polymer particles. When the sum of the total weight of the hydrophobic material in the composition is too low, the effect of imparting hydrophobicity by the hydrophobic material is small, so it may be difficult to suppress the caking phenomenon, and when the sum of the total weight of the hydrophobic material is too high The physical properties of water holding capacity and absorbency under pressure may be reduced.
[100]
In addition, the first hydrophobic material and the second hydrophobic material may be included in a molar ratio of 3:7 to 7:3. Based on the total moles of the hydrophobic material, when the molar ratio of the first hydrophobic material is too high, there may be a problem in that the absorption rate of the superabsorbent polymer is lowered. Since the effect of imparting hydrophobicity is small, aggregation between particles may not be suppressed.
[101]
Meanwhile, at least a portion of the first hydrophobic material and the second hydrophobic material may be present on the surface of the superabsorbent polymer particles. Here, “at least a portion of the first hydrophobic material and the second hydrophobic material is present on the surface of the superabsorbent polymer particles” means that at least a portion of the first hydrophobic material and the second hydrophobic material is the superabsorbent polymer particle means that it is adsorbed or bound to the surface of Specifically, the first hydrophobic material and the second hydrophobic material may be physically or chemically adsorbed to the surface of the superabsorbent polymer. More specifically, the hydrophilic functional groups of the first hydrophobic material and the second hydrophobic material are physically adsorbed to the hydrophilic portion of the surface of the superabsorbent polymer by intermolecular forces such as dipole-dipole interaction. have. As such, the hydrophilic portion of the first hydrophobic material and the second hydrophobic material is physically adsorbed to the surface of the superabsorbent polymer particle to surround the surface, and the hydrophobic portion of the first hydrophobic material and the second hydrophobic material is the surface of the resin particle Since it is not adsorbed to the superabsorbent polymer particles, the portion to which the hydrophobic material is adsorbed may exhibit hydrophobicity.
[102]
Therefore, when at least a portion of the first hydrophobic material and the second hydrophobic material represented by Formula 1 is present on the surface of the superabsorbent polymer particle, all of the hydrophobic material is inside the superabsorbent polymer particle, specifically, the crosslinked polymer Compared to a case in which the superabsorbent polymer particles are present in the interior of the , aggregation of the superabsorbent polymer particles when exposed to air can be more effectively suppressed.
[103]
[104]
Meanwhile, the superabsorbent polymer composition may further include, on at least a portion of the surface of the superabsorbent polymer particles, a surface crosslinking layer formed by further crosslinking the crosslinked polymer through a surface crosslinking agent. This is to increase the surface crosslinking density of the superabsorbent polymer particles. As described above, when the superabsorbent polymer particles further include a surface crosslinking layer, the superabsorbent polymer particles have a structure having a higher crosslinking density on the outside than on the inside.
[105]
As the surface crosslinking agent, any surface crosslinking agent that has been conventionally used in the production of superabsorbent polymers may be used without particular limitation. For example, the surface crosslinking agent is ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, 2- One selected from the group consisting of methyl-1,3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, tripropylene glycol and glycerol more than one polyol; at least one carbonate-based compound selected from the group consisting of ethylene carbonate, propylene carbonate, and glycerol carbonate; Epoxy compounds, such as ethylene glycol diglycidyl ether; oxazoline compounds such as oxazolidinone; polyamine compounds; oxazoline compounds; mono-, di- or polyoxazolidinone compounds; or a cyclic urea compound; and the like.
[106]
Specifically, one or more, or two or more, or three or more of the above-mentioned surface crosslinking agents may be used as the surface crosslinking agent, for example, ethylene carbonate-propylene carbonate (ECPC), propylene glycol and/or glycerol carbonate can be used.
[107]
[108]
In addition, the superabsorbent polymer composition may be about 90% by weight, preferably 95% by weight or more, based on the total weight of the superabsorbent polymer particles having a particle diameter of about 150 to 850 μm.
[109]
In addition, the superabsorbent polymer composition has a water holding capacity (CRC) of 30 g/g or more, or 31 g/g or more, or 33 g/g or more, and 40 g/g or less, measured according to EDANA method WSP 241.3, or 38 g/g or less, or 37 g/g or less.
[110]
In addition, the superabsorbent polymer composition has an absorbency under pressure (AUP) of 18 g/g or more, or 20 g/g or more, or 22 g/g or more, at 0.3 psi measured according to EDANA method WSP 242.3, and 27 g/g/g or more. g or less, or 25 g/g or less.
[111]
In addition, the superabsorbent composition has an anti-caking efficiency (A/C, anti-caking) of 20% or more, more specifically 30% or more, 40% or more, or 50% or more, and the higher the value, the better, There is no upper limit of the anti-caking efficiency, but for example, it may be 75% or less, 70% or less, or 65% or less. At this time, the anti-caking efficiency is calculated by the following Equation 3:
[112]
[Equation 3]
[113]
A/C(%) = W 6 /W 5　× 100　
[114]
In Equation 3 above,
[115]
W 5 is the weight (g) of the superabsorbent polymer composition applied to the 10 cm diameter flask dish,　
[116]
For W 6 , after evenly applying the superabsorbent polymer composition to a flask dish with a diameter of 10 cm, hold it for 10 minutes in a constant temperature and humidity chamber maintaining a temperature of 40±3 ℃ and a humidity of 80±3%, and then place the flask dish on the filter paper. It is the weight (g) of the superabsorbent polymer composition falling from the flask dish after turning it over and lightly taping it three times.
[117]
In addition, the superabsorbent polymer composition is prepared by adding 2 g of the superabsorbent polymer composition to 50 mL of physiological saline at 23° C. to 24° C., and stirring a magnetic bar (diameter 8 mm, length 30 mm) at 600 rpm, while stirring the upper part of the liquid The wetting time, which is defined as the total time for which the superabsorbent polymer composition is not wetted, is 15 seconds or less, more specifically 13 seconds or less, 10 seconds or less, or 5 seconds or less, and the smaller the value, the better. The lower limit of the wettability is 0 seconds in theory, but is, for example, 1 second or more.
[118]
In this case, the method of measuring the physical properties of the superabsorbent polymer composition will be more detailed in Examples below.
[119]
[120]
Therefore, as described above, when two types of hydrophobic materials satisfying a specific chemical formula are used simultaneously, the caking prevention efficiency (A/C) calculated by Equation 3 is 20% or more, and the wetting time is 15 It is possible to provide a superabsorbent polymer composition excellent in both absorption performance and caking prevention efficiency of seconds or less.
[121]
[122]
Method for preparing super absorbent polymer composition
[123]
On the other hand, according to another embodiment of the present invention, in the presence of an internal crosslinking agent and a polymerization initiator, the steps of crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acidic group to form a hydrogel polymer; preparing a pulverized product including water-containing superabsorbent polymer particles and the hydrophobic composition by adding a hydrophobic composition including a first hydrophobic material and a second hydrophobic material to the water-containing gel polymer and pulverizing the hydrophobic composition; and drying the pulverized material to prepare a superabsorbent polymer composition including the superabsorbent polymer particles, the first hydrophobic material, and the second hydrophobic material.
[124]
[125]
Hereinafter, each step of the manufacturing method of the superabsorbent polymer according to one embodiment will be described in more detail.
[126]
[127]
In the method for producing a superabsorbent polymer according to one embodiment, first, in the presence of an internal crosslinking agent and a polymerization initiator, a step of crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized to form a hydrogel polymer is performed. .
[128]
The step may include preparing a monomer composition by mixing the water-soluble ethylenically unsaturated monomer, an internal crosslinking agent, and a polymerization initiator, and thermally or photopolymerizing the monomer composition to form a hydrogel polymer. In this case, the description of the water-soluble ethylenically unsaturated monomer and the internal crosslinking agent refer to the above-mentioned bar.
[129]
In the monomer composition, the internal crosslinking agent may be used in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. For example, the internal crosslinking agent is 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight, or 0.2 parts by weight or more, and 5 parts by weight or less, 3 parts by weight or less, or 2 parts by weight based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. parts by weight or less, 1 part by weight or less, or 0.5 part by weight or less. If the content of the upper internal crosslinking agent is too low, crosslinking does not occur sufficiently, and it may be difficult to implement strength above an appropriate level.
[130]
In addition, the polymerization initiator may be appropriately selected depending on the polymerization method. When using the thermal polymerization method, a thermal polymerization initiator is used, and when using the photopolymerization method, a photopolymerization initiator is used, and a hybrid polymerization method (thermal and light). both of the thermal polymerization initiator and the photopolymerization initiator can be used. However, even by the photopolymerization method, a certain amount of heat is generated by light irradiation such as ultraviolet irradiation, and a certain amount of heat is generated according to the progress of the polymerization reaction, which is an exothermic reaction, so a thermal polymerization initiator may be additionally used.
[131]
The photopolymerization initiator may be used without limitation in its composition as long as it is a compound capable of forming radicals by light such as ultraviolet rays.
[132]
As the photopolymerization initiator, for example, benzoin ether, dialkyl acetophenone, hydroxyl alkylketone, phenyl glyoxylate, benzyl dimethyl ketal Ketal), acyl phosphine (acyl phosphine) and alpha-aminoketone (α-aminoketone) may be used at least one selected from the group consisting of. On the other hand, specific examples of acylphosphine include diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide, phenylbis (2,4,6-trimethylbenzoyl) phosphine oxide, ethyl (2,4,6- trimethylbenzoyl)phenylphosphinate etc. are mentioned. A more diverse photoinitiator is well described in Reinhold Schwalm's book "UV Coatings: Basics, Recent Developments and New Application (Elsevier 2007)" p115, but is not limited to the above-described examples.
[133]
In addition, as the thermal polymerization initiator, at least one selected from the group consisting of a persulfate-based initiator, an azo-based initiator, hydrogen peroxide, and ascorbic acid may be used. Specifically, examples of the persulfate-based initiator 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) and the like, and examples of the azo initiator include 2,2-azobis-(2-amidinopropane) dihydrochloride (2,2-azobis(2-amidinopropane) dihydrochloride), 2,2-azobis -(N,N-dimethylene)isobutyramidine dihydrochloride (2,2-azobis-(N,N-dimethylene)isobutyramidine dihydrochloride), 2-(carbamoylazo)isobutyronitrile (2-(carbamoylazo) )isobutylonitril), 2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride (2,2-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride ), 4,4-azobis-(4-cyanovaleric acid) (4,4-azobis-(4-cyanovaleric acid)) and the like. More various thermal polymerization initiators are well described in Odian's book 'Principle of Polymerization (Wiley, 1981)', p203, and are not limited to the above-described examples.
[134]
The polymerization initiator may be used in an amount of 2 parts by weight or less based on 100 parts by weight of the water-soluble ethylenically unsaturated monomer. That is, when the concentration of the polymerization initiator is too low, the polymerization rate may be slowed and the residual monomer may be extracted in a large amount in the final product, which is not preferable. Conversely, when the concentration of the polymerization initiator is higher than the above range, the polymer chain constituting the network is shortened, so that the content of the water-soluble component is increased and the physical properties of the resin may be lowered, such as lowered absorbency under pressure, which is not preferable.
[135]
The monomer composition may further include a first hydrophobic material and a second hydrophobic material such as a thickener, a plasticizer, a preservation stabilizer, and an antioxidant, as needed.
[136]
In addition, the monomer composition including the monomer may be in a solution state dissolved in a solvent such as water, and the solid content in the monomer composition in the solution state, that is, the concentration of the monomer, the internal crosslinking agent, and the polymerization initiator It may be appropriately adjusted in consideration of time and reaction conditions. For example, the solid content in the monomer composition may be 10 to 80% by weight, or 15 to 80% by weight, or 20 to 60% by weight.
[137]
When the monomer composition has a solid content in the above range, it is not necessary to remove unreacted monomers after polymerization by using the gel effect phenomenon that occurs in the polymerization reaction of a high concentration aqueous solution. It can be advantageous to control.
[138]
The solvent that can be used at this time can be used without limitation in its composition as long as it can dissolve the above-mentioned components, for example, water, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, propylene Glycol, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, methyl ethyl ketone, acetone, methyl amyl ketone, cyclohexanone, cyclopentanone, diethylene glycol monomethyl ether, diethylene glycol ethyl At least one selected from ether, toluene, xylene, butyrolactone, carbitol, methyl cellosolve acetate and N,N-dimethylacetamide may be used in combination.
[139]
On the other hand, cross-linking polymerization of a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acidic group may be carried out without particular limitation on the structure, as long as the hydrogel polymer can be formed by thermal polymerization, photopolymerization, or hybrid polymerization.
[140]
Specifically, the polymerization method is largely divided into thermal polymerization and photopolymerization depending on the polymerization energy source. In general, when thermal polymerization is carried out, it may be carried out in a reactor having a stirring shaft such as a kneader. The polymerization may be carried out in a reactor equipped with a conveyor belt or in a flat-bottomed vessel, but the polymerization method described above is an example, and the present invention is not limited to the polymerization method described above.
[141]
For example, as described above, the hydrogel polymer obtained by thermal polymerization by supplying hot air or heating the reactor to a reactor such as a kneader having a stirring shaft is fed 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. Specifically, the size of the hydrogel polymer obtained may vary depending on the concentration and injection speed of the monomer composition to be injected, and a hydrogel polymer having a weight average particle diameter of 2 to 50 mm can be obtained.
[142]
In addition, as described above, when photopolymerization is performed in a reactor equipped with a movable conveyor belt or a flat-bottomed container, the form of the hydrogel polymer obtained may be a hydrogel polymer on a sheet having the width of the belt. At this time, the thickness of the polymer sheet varies depending on the concentration of the injected monomer composition and the injection rate or injection amount, but it is preferable to supply the monomer composition so that a polymer sheet having a thickness of about 0.5 to about 5 cm can be obtained. . When the monomer composition is supplied so that the thickness of the polymer on the sheet is too thin, the production efficiency is low, which is not preferable. it may not be
[143]
The polymerization time of the monomer composition is not particularly limited and may be adjusted to about 30 seconds to 60 minutes.
[144]
In this case, the hydrogel polymer obtained by this method may have a moisture content of 30 to 70 wt%. For example, the water content of the hydrogel polymer may be 40 wt% or more, or 45 wt% or more, and 70 wt% or less, 65 wt% or less, 60 wt% or less, or 50 wt% or less. The water content of the hydrogel polymer is difficult to be less than 30% by weight in terms of polymerization progress, and when the water content of the hydrogel polymer is too high, the hydrophobic composition penetrates into the polymer and the inhibition of aggregation between the prepared particles may not be large.
[145]
Meanwhile, throughout the present specification, "moisture content" refers to a value obtained by subtracting the weight of the polymer in a dry state from the weight of the hydrogel polymer as the content of moisture occupied with respect to the total weight of the hydrogel polymer. Specifically, it is defined as a value calculated by measuring the weight loss due to evaporation of moisture in the polymer during drying by raising the temperature of the polymer in the crumb state through infrared heating. At this time, the drying conditions are set to 40 minutes including 5 minutes of the temperature rise step in such a way that the temperature is raised from room temperature to about 180° C. and then maintained at 180° C., and the moisture content is measured.
[146]
[147]
Next, a hydrophobic composition including a first hydrophobic material and a second hydrophobic material is added to the hydrophobic gel polymer and then pulverized to prepare a pulverized product including the water-containing superabsorbent polymer particles and the hydrophobic composition. For details on the first hydrophobic material and the second hydrophobic material, refer to the above bar.
[148]
In a conventional method for preparing a superabsorbent polymer, the superabsorbent polymer is prepared by coarsely pulverizing the hydrogel polymer without adding a hydrophobic material, and then drying and pulverizing it to a desired particle size. In this case, the superabsorbent polymer coarsely pulverized by the water used during the process may agglomerate or agglomerate, which may increase the internal load and cause equipment failure. In addition, strong force must be applied to pulverize the agglomerated superabsorbent polymer to a desired particle size, so that there is a problem in that the physical properties of the superabsorbent polymer are deteriorated.
[149]
However, as described above, when pulverization is performed together with the first hydrophobic material and the second hydrophobic material in the hydrogel polymer state, it is possible to prepare a group of particles having a desired particle size without aggregation of the pulverized particles. do. Accordingly, in the method of manufacturing the superabsorbent polymer composition according to the exemplary embodiment, it is possible to pulverize the superabsorbent polymer composition into particles having a desired particle size without applying a strong force, so that the manufacturing cost of the superabsorbent polymer can be greatly reduced.
[150]
In the above step, the total weight of the first hydrophobic material and the second hydrophobic material may be used in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the hydrogel polymer. Specifically, the first hydrophobic material and the second hydrophobic material are used in an amount of 0.1 parts by weight or more, or 0.2 parts by weight or more, and 1 part by weight or less, 0.8 parts by weight or less, or 0.5 parts by weight or less, based on 100 parts by weight of the hydrogel polymer. can be used When too little of the first hydrophobic material and the second hydrophobic material are used, the hydrophobic material is not evenly applied to the surface of the hydrogel polymer, so the effect of imparting hydrophobicity may be small, and the first hydrophobic material and the second hydrophobic material are excessively If it is used a lot, the overall physical properties of the finally prepared super absorbent polymer may be deteriorated.
[151]
Each of the first hydrophobic material and the second hydrophobic material may be included in the hydrophobic composition as a raw material, or may be included in an aqueous dispersion form.
[152]
More specifically, the first hydrophobic material and the second hydrophobic material may be added to the hydrogel polymer as a raw material itself. At this time, when the first hydrophobic material is in a solid state at room temperature, It can be melted by heat and adsorbed to the pulverized polymer particles.
[153]
Alternatively, the first hydrophobic material and the second hydrophobic material may be added in a mixed state in water. That is, the hydrophobic composition may further include water, and in this case, the solid content of the hydrophobic composition may be 0.5% by weight or more and less than 100% by weight. The hydrophobic composition having a solid content in the above range is suitable in terms of being uniformly applied to the hydrogel polymer.
[154]
The hydrophobic composition may be put into a reactor in which the hydrogel polymer is prepared and mixed, or may be injected and injected together with the hydrogel polymer in a mixer, or may be continuously supplied together with the hydrogel polymer to a continuously operated mixer.
[155]
The hydrophobic composition may be added to the hydrogel polymer and then pulverized so that the water-containing superabsorbent polymer particles, the first hydrophobic material, and the second hydrophobic water-containing superabsorbent polymer particles have a particle diameter of 300 μm to 5000 μm. Here, "water-containing superabsorbent polymer particles" are particles having a moisture content (moisture content) of about 40% by weight or more, and since the hydrogel polymer is pulverized into particles without a separate drying process, 30 to 70 similar to the hydrogel polymer It may have a moisture content of weight %. The particle size may be measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 220.3 method.
[156]
At this time, the pulverizer used for pulverization is specifically, a vertical pulverizer, a turbo cutter, a turbo grinder, a rotary cutter mill, a cutting pulverizer ( Cutter mill), a disc mill, a shred crusher, a crusher, a chopper and a disc cutter may include any one selected from the group consisting of a grinding device , but is not limited to the above example.
[157]
However, in terms of process stability, it is preferable to perform the grinding process by a chopper.
[158]
Meanwhile, at least a portion of the first hydrophobic material and the second hydrophobic material included in the pulverized material may be present on the surface of the water-containing superabsorbent polymer particles. As described above, “at least a portion of the first hydrophobic material and the second hydrophobic material is present on the surface of the water-containing superabsorbent polymer particles” means that at least a portion of the first hydrophobic material and the second hydrophobic material is It means that it is adsorbed or bound to the surface of the water-containing superabsorbent polymer particles. This is because the hydrophobic material is not added during the polymerization process of the water-soluble ethylenically unsaturated monomer, but after the polymer is formed. Re-agglomeration between the resin particles can be suppressed.
[159]
[160]
Next, drying the pulverized material to prepare a superabsorbent polymer composition including the superabsorbent polymer particles, the first hydrophobic material, and the second hydrophobic material is performed.
[161]
Drying of the pulverized product may be performed so that the moisture content of each of the plurality of superabsorbent polymer particles included in the prepared superabsorbent polymer composition is about 10% by weight or less, specifically, about 0.1 to about 10% by weight.
[162]
At this time, the drying temperature may be about 60 ℃ to about 250 ℃. In this case, when the drying temperature is too low, the drying time may be too long. When the drying temperature is too high, only the surface of the polymer is dried, and there is a risk that the physical properties of the superabsorbent polymer to be finally formed may decrease. Therefore, preferably, the drying may be carried out at a temperature of about 100 °C to about 240 °C, more preferably at a temperature of about 110 °C to about 220 °C.
[163]
In addition, the drying time may be carried out for about 20 minutes to about 12 hours in consideration of process efficiency and the like. For example, it may be dried for about 10 minutes to about 100 minutes, or about 20 minutes to about 60 minutes.
[164]
If the drying method of the drying step is also commonly used as a drying process, it may be selected and used without limitation in its configuration. Specifically, the drying step may be performed by a method such as hot air supply, infrared irradiation, microwave irradiation, or ultraviolet irradiation.
[165]
In addition, after the drying step of the pulverized material, the final manufactured super absorbent polymer particles may be pulverized using a pulverizer to consist of particles having a diameter of about 150 μm to about 850 μm.
[166]
At this time, the pulverizer used for pulverization is specifically, a pin mill, a hammer mill, a screw mill, a roll mill, a disc mill, or a jog mill ( jog mill), but is not limited to the above-described example.
[167]
[168]
Thereafter, if necessary, the method may further include forming a surface crosslinking layer on at least a portion of the surface of the superabsorbent polymer particles in the presence of a surface crosslinking agent. Through the above step, the crosslinked polymer included in the superabsorbent polymer particles may be further crosslinked through the surface crosslinking agent to form a surface crosslinking layer on at least a portion of the surface of the superabsorbent polymer particles.
[169]
The surface crosslinking agent may be used in an amount of about 0.001 to about 5 parts by weight based on 100 parts by weight of the superabsorbent polymer particles. For example, the surface crosslinking agent is 0.005 parts by weight or more, 0.01 parts by weight or more, or 0.05 parts by weight or more, and 5 parts by weight or less, 4 parts by weight or less, or 3 parts by weight or less based on 100 parts by weight of the superabsorbent polymer particles. content can be used. By adjusting the content range of the surface crosslinking agent to the above-mentioned range, it is possible to prepare a superabsorbent polymer having excellent absorbent properties.
[170]
In addition, the step of forming the surface crosslinking layer may be performed by adding an inorganic material to the surface crosslinking agent. That is, in the presence of the surface crosslinking agent and the inorganic material, the step of further crosslinking the surface of the superabsorbent polymer particles to form a surface crosslinking layer may be performed.
[171]
As the inorganic material, at least one inorganic material selected from the group consisting of silica, clay, alumina, silica-alumina composite, titania, zinc oxide, and aluminum sulfate may be used. The inorganic material may be used in powder form or liquid form, and in particular, may be used as alumina powder, silica-alumina powder, titania powder, or nano-silica solution. In addition, the inorganic material may be used in an amount of about 0.001 to about 1 part by weight based on 100 parts by weight of the superabsorbent polymer particles.
[172]
In addition, there is no limitation on the composition of the method of mixing the surface crosslinking agent with the superabsorbent polymer composition. For example, a method of mixing the surface crosslinking agent and the superabsorbent polymer composition in a reaction tank, spraying the surface crosslinking agent to the superabsorbent polymer composition, or continuously supplying and mixing the superabsorbent polymer composition and the surface crosslinking agent to a continuously operated mixer method and the like can be used.
[173]
When the surface crosslinking agent and the superabsorbent polymer composition are mixed, water and methanol may be mixed and added. When water and methanol are added, there is an advantage that the surface crosslinking agent can be uniformly dispersed in the superabsorbent polymer composition. In this case, the content of the added water and methanol may be appropriately adjusted to induce even dispersion of the surface crosslinking agent, prevent agglomeration of the superabsorbent polymer composition, and at the same time optimize the surface penetration depth of the crosslinking agent.
[174]
The surface crosslinking process may be performed at a temperature of about 80 °C to about 250 °C. More specifically, the surface crosslinking process may be performed at a temperature of about 100°C to about 220°C, or about 120°C to about 200°C, for about 20 minutes to about 2 hours, or about 40 minutes to about 80 minutes. . When the above-mentioned surface crosslinking process conditions are satisfied, the surface of the superabsorbent polymer particles may be sufficiently crosslinked to increase absorbency under pressure.
[175]
A means for increasing the temperature for the surface crosslinking reaction is not particularly limited. It can be heated by supplying a heating medium or by directly supplying a heat source. At this time, as the type of heating medium that can be used, a fluid having an elevated temperature such as steam, hot air, or hot oil may be used, but the present invention is not limited thereto. Considering it, it can be appropriately selected. On the other hand, the directly supplied heat source may be a heating method through electricity or a heating method through a gas, but is not limited to the above-described example.
[176]
[177]
Hereinafter, preferred embodiments are presented to help the understanding of the invention. However, the following examples are only for illustrating the invention, and do not limit the invention thereto.
[178]
[179]
Example - Preparation of super absorbent polymer composition
[180]
Example 1
[181]
In a 3L glass container equipped with a stirrer and a thermometer, 100 g (1.388 mol) of acrylic acid, 0.26 g of polyethylene glycol diacrylate (PEGDA, Mw=400) as an internal crosslinking agent, and diphenyl (2,4,6-trimethylbenzoyl) phosphine as a photopolymerization initiator 0.008 g of fin oxide, 0.20 g of sodium persulfate, a thermal polymerization initiator, and 123.5 g of a 32% caustic soda solution were mixed with 40.0 g of water at room temperature to prepare a monomer composition (neutralization degree of acrylic acid: 70 mol%, solid content 45.0 weight%).
[182]
Thereafter, the monomer composition was supplied at a rate of 500 to 2000 mL/min on a conveyor belt in which a belt having a width of 10 cm and a length of 2 m was rotated at a speed of 50 cm/min. And, at the same time as the supply of the monomer composition, the polymerization reaction was carried out for 60 seconds by irradiating ultraviolet rays having an intensity of 10 mW/cm 2 to obtain a hydrogel polymer having a water content of 46.5 wt%.
[183]
Next, stearic acid (represented by the following formula 1-1, manufactured by LG Household & Health Care) and laureth-6 carboxylic acid (Laureth-6 carboxylic acid, After the hydrophobic composition (solvent: water, solid content 2.91% by weight) was added so that the total weight of the hydrogel polymer (represented by the following Chemical Formula 2-1, manufactured by KAO) was 0.3 parts by weight based on 100 parts by weight of the hydrogel polymer, a meat chopper was used to pulverize the hydrogel polymer into particles having a particle diameter of 300 μm to 5000 μm. At this time, the moisture content of the water-containing superabsorbent polymer particles included in the pulverized pulverized product was 46% by weight.
[184]
Thereafter, the pulverized product was dried in hot air at 185° C. for 30 minutes using an air-flow oven.
[185]
A solution of 3.2 g of ultrapure water, 4.5 g of methanol, and 0.13 g of ethylene carbonate was administered to 100 g of the dried product dried in the above step, and mixed using a magnetic stirrer for 1 minute, and then at 198 ° C. for 60 minutes using a convection oven. A surface crosslinking reaction was performed. Thereafter, they were classified to prepare a superabsorbent polymer composition containing superabsorbent polymer particles having a size of 150 to 850 μm.
[186]
[Formula 1-1]
[187]

[188]
[Formula 2-1]
[189]

[190]
[191]
Example 2
[192]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that a hydrophobic composition containing stearic acid and laureth-6 carboxylic acid having a molar ratio of 5:5 in Example 1 was used.
[193]
[194]
Example 3
[195]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that a hydrophobic composition containing stearic acid and laureth-6 carboxylic acid having a molar ratio of 3:7 in Example 1 was used.
[196]
[197]
Example 4
[198]
Example 1, except that in Example 1, a hydrophobic composition containing myristic acid represented by the following formula 1-2 (Myristic acid, manufactured by Sigma Aldrich) was used instead of the stearic acid represented by the formula 1-1. A superabsorbent polymer composition was prepared using the same method as described above.
[199]
[Formula 1-2]
[200]

[201]
[202]
Example 5
[203]
In Example 1, instead of the hydrophobic composition containing stearic acid represented by Formula 1-1 and laureth-6 carboxylic acid represented by Formula 2-1, myristic acid represented by Formula 1-2 and Formula 2 below A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that a hydrophobic composition containing laureth-11 carboxylic acid (manufactured by KAO) represented by -2 was used. did
[204]
[Formula 2-2]
[205]

[206]
[207]
Example 6
[208]
Example 1, except that in Example 1, a hydrophobic composition containing palmitic acid represented by the following formula 1-3 (Palmitic acid, manufactured by Sigma Aldrich) was used instead of the stearic acid represented by the formula 1-1. A superabsorbent polymer composition was prepared using the same method as described above.
[209]
[Formula 1-3]
[210]

[211]
[212]
Example 7
[213]
In Example 1, instead of the hydrophobic composition containing the stearic acid represented by Formula 1-1 and laureth-6 carboxylic acid represented by Formula 2-1, palmitic acid represented by Formula 1-3 and Formula 2 A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that the hydrophobic composition containing laureth-11 carboxylic acid represented by -2 was used.
[214]
[215]
Comparative Example 1
[216]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that the hydrophobic composition was not used in Example 1.
[217]
[218]
Comparative Example 2
[219]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that the hydrophobic composition containing only stearic acid was used in Example 1.
[220]
[221]
Comparative Example 3
[222]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that the hydrophobic composition containing only laureth-6 carboxylic acid was used in Example 1.
[223]
[224]
Comparative Example 4
[225]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that a hydrophobic composition containing a compound represented by the following formula (A) was used instead of stearic acid in Example 1.
[226]
[Formula A]
[227]

[228]
[229]
Comparative Example 5
[230]
A superabsorbent polymer composition was prepared in the same manner as in Example 1, except that in Example 1, a hydrophobic composition containing a compound represented by Formula B was used instead of laureth-6 carboxylic acid.
[231]
[Formula B]
[232]

[233]
[234]
test example
[235]
For the superabsorbent polymer compositions prepared in Examples and Comparative Examples, centrifugal separation capacity (CRC), absorbency under pressure (AUP), wetting time and caking prevention efficiency (A/C, Anti -caking) was measured, and the results are shown in Table 1 below.
[236]
[237]
(1) Centrifuge Retention Capacity (CRC)
[238]
The water holding capacity of each resin according to the no-load absorption magnification was measured according to the European Disposables and Nonwovens Association (EDANA) standard EDANA WSP 241.3.
[239]
Specifically, in the resin compositions obtained through Examples and Comparative Examples, a resin classified through a sieve of #30-50 was obtained. This resin W 0 (g) (about 0.2 g) was uniformly put in a non-woven bag and sealed, and then immersed in physiological saline (0.9 wt %) at room temperature. After 30 minutes, the bag was drained of water for 3 minutes under the conditions of 250G using a centrifuge, and the mass W 2 (g) of the bag was measured. Moreover, after performing the same operation without using resin, the mass W1 (g) at that time was measured.
[240]
CRC (g/g) was calculated according to Equation 1 below using each obtained mass.
[241]
[Equation 1]
[242]
CRC (g/g) = {[W 2 (g) - W 1 (g)]/W 0 (g)} - 1
[243]
[244]
(2) Absorbency under Pressure (AUP: Absorbency under Pressure)
[245]
The absorbency under pressure of 0.3 psi of the superabsorbent polymer compositions of Examples and Comparative Examples was measured according to the EDANA method WSP 242.3.
[246]
First, when measuring the absorbency under pressure, the resin fraction at the time of the CRC measurement was used.
[247]
Specifically, a stainless steel 400 mesh wire mesh was mounted on the bottom of a plastic cylinder having an inner diameter of 25 mm. Under the condition of room temperature and humidity of 50%, the water absorbent resin W 0 (g) (0.16 g) is uniformly sprayed on the wire mesh, and the piston that can apply a load of 0.3 psi more uniformly thereon is slightly smaller than the outer diameter of 25 mm There is no gap between the inner wall of the cylinder and the vertical movement is not disturbed. At this time, the weight W 3 (g) of the device was measured.
[248]
A glass filter having a diameter of 90 mm and a thickness of 5 mm was placed on the inside of a 150 mm diameter petro dish, and physiological saline composed of 0.9 wt% sodium chloride was placed at the same level as the upper surface of the glass filter. One filter paper having a diameter of 90 mm was loaded thereon. The measuring device was placed on the filter paper, and the liquid was absorbed under load for 1 hour. After 1 hour, the measuring device was lifted and the weight W 4 (g) was measured.
[249]
Using each obtained mass, the absorbency under pressure (g/g) was calculated according to the following Equation (2).
[250]
[Equation 2]
[251]
AUP(g/g) = [W 4 (g) - W 3 (g)]/W 0 (g)
[252]
[253]
(3) wetting time
[254]
The wettability of the superabsorbent polymers of Examples and Comparative Examples was measured in seconds according to the method described in International Publication No. 1987-003208 for measuring the vortex time.
[255]
Specifically, 2 g of superabsorbent polymer is added to 50 mL of physiological saline at 23° C. to 24° C., and while stirring the magnetic bar (8 mm in diameter, 30 mm in length) at 600 rpm, the non-wet superabsorbent resin is added to the upper part of the liquid. The total time observed was determined. The longer the time, the worse the wettability can be evaluated.
[256]
[257]
(4) Caking prevention efficiency (A/C, Anti-caking)
[258]
After evenly applying 2 g (W 5 ) of the superabsorbent polymer composition prepared in Examples and Comparative Examples to a flask dish with a diameter of 10 cm, a temperature of 40±3° C. and a humidity of 80±3% were maintained in a constant temperature and humidity chamber for 10 minutes. After holding for a while, the flask dish was turned over on the filter paper and the amount of superabsorbent polymer falling off (W 6 ) was measured after taping three times .
[259]
Using the measured weight, the casing prevention efficiency was calculated according to the following Equation 3, and the higher the value, the better the efficiency.
[260]
[Equation 3]
[261]
A/C(%) = W 6 /W 5　× 100　
[262]
In Equation 3 above,
[263]
W 5 is the weight (g) of the superabsorbent polymer composition applied to the 10 cm diameter flask dish,　
[264]
For W 6 , after evenly applying the superabsorbent polymer composition to a flask dish with a diameter of 10 cm, hold it for 10 minutes in a constant temperature and humidity chamber maintaining a temperature of 40±3℃ and a humidity of 80±3%, and then place the flask dish on the filter paper. It is the weight (g) of the superabsorbent polymer composition falling from the flask dish after turning over and lightly taping 3 times.
[265]
[266]
[Table 1]
first hydrophobic material second hydrophobic material Molar ratio between hydrophobic substances SAP properties
CRC (g/g) AUP (g/g) Wettability (sec) A/C efficiency (%)
Example 1 1-1 2-1 7:3 34.9 23.7 5 61
Example 2 1-1 2-1 5:5 35.8 24.4 3 58
Example 3 1-1 2-1 3:7 34.9 24.1 2 51
Example 4 1-2 2-1 7:3 36.3 23.2 4 55
Example 5 1-2 2-2 7:3 35.9 23.6 3 50
Example 6 1-3 2-1 7:3 36.1 23.3 4 57
Example 7 1-3 2-2 7:3 35.7 24.0 3 53
Comparative Example 1 - - - 36.9 25.0 One 0
Comparative Example 2 1-1 - 10:0 35.4 22.4 20 76
Comparative Example 3 - 2-1 0:10 34.6 25.8 One 11
Comparative Example 4 A 2-1 7:3 35.6 22.2 3 16
Comparative Example 5 1-1 B 7:3 35.1 25.1 One 5
[267]
[268]
Referring to Table 1, the superabsorbent polymer composition of Examples prepared by adding both the first hydrophobic material and the second hydrophobic material when pulverizing the hydrogel polymer does not use such a hydrophobic material or uses only one hydrophobic material. Unlike the superabsorbent polymer composition of Comparative Example, in which either one of the two types of hydrophobic material is used or the hydrophobic material of the present application does not correspond to the hydrophobic material of the present application, the wettability is 15 seconds or less and the anti-caking efficiency (A/C) of 20% or more indicates
[269]
Accordingly, it can be confirmed that the superabsorbent polymer composition with improved anti-caking efficiency can be prepared without deterioration in absorption performance when the hydrogel polymer is pulverized in the presence of two types of hydrophobic materials having different hydrophobic properties.
Claims
[Claim 1]
superabsorbent polymer particles comprising a crosslinked polymer of a water-soluble ethylenically unsaturated monomer having at least a partially neutralized acidic group; a first hydrophobic material; and a second hydrophobic material, wherein the first hydrophobic material includes a carboxylic acid or a salt thereof represented by the following Chemical Formula 1, and the second hydrophobic material includes a carboxylic acid or a salt thereof represented by the following Chemical Formula 2 Superabsorbent polymer composition comprising: [Formula 1] In Formula 1, x is an integer of 10 to 20, [Formula 2] In Formula 2, y is an integer of 5 to 15, z is an integer of 1 to 10 to be.
[Claim 2]
The superabsorbent polymer composition of claim 1, wherein at least a portion of the first hydrophobic material and the second hydrophobic material is present on the surface of the superabsorbent particles.
[Claim 3]
The superabsorbent polymer composition of claim 1, wherein x is an integer of 11 to 15, y is 11, and z is an integer of 5 to 10.
[Claim 4]
The superabsorbent polymer composition of claim 1, wherein the first hydrophobic material is in a solid phase at 25°C, and the second hydrophobic material is in a liquid phase at 25°C.
[Claim 5]
The superabsorbent polymer composition of claim 1, wherein the first hydrophobic material and the second hydrophobic material are included in a molar ratio of 3:7 to 7:3.
[Claim 6]
The superabsorbent polymer composition according to claim 1, further comprising a surface crosslinking layer formed by further crosslinking the crosslinked polymer via a surface crosslinking agent on at least a portion of the surface of the superabsorbent polymer particles.
[Claim 7]
The method of claim 1, wherein the superabsorbent polymer composition has an anti-caking efficiency (A/C) of 20% or more, calculated by Equation 3 below, and 2 g of the superabsorbent polymer in 50 mL of physiological saline at 23°C to 24°C. Putting the water absorbent resin composition and stirring the magnetic bar (diameter 8 mm, length 30 mm) at 600 rpm, the wetting time defined as the total time for the superabsorbent polymer composition not to be wetted on the liquid upper part is 15 seconds or less , Super absorbent polymer composition: [Equation 3] A/C (%) = W 6 /W 5　× 100 In Equation 3, W 5 is the weight of the superabsorbent polymer composition applied to the flask dish with a diameter of 10 cm (g) ), and W 6 is after evenly applying the superabsorbent polymer composition to a 10 cm diameter flask dish and maintaining it for 10 minutes in a constant temperature and humidity chamber maintaining a temperature of 40±3 ℃ and a humidity of 80±3%, and then It is the weight (g) of the superabsorbent polymer composition falling from the flask plate after turning the flask plate over and lightly taping it three times.
[Claim 8]
forming a hydrogel polymer by crosslinking and polymerizing a water-soluble ethylenically unsaturated monomer having an acidic group at least partially neutralized in the presence of an internal crosslinking agent and a polymerization initiator; preparing a pulverized product including water-containing superabsorbent polymer particles and the hydrophobic composition by adding a hydrophobic composition including a first hydrophobic material and a second hydrophobic material to the water-containing gel polymer and pulverizing the hydrophobic composition; and drying the pulverized material to prepare a superabsorbent polymer composition including superabsorbent polymer particles, the first hydrophobic material, and the second hydrophobic material, wherein the first hydrophobic material is represented by the following formula (1) A method for preparing a superabsorbent polymer composition comprising a carboxylic acid or a salt thereof, wherein the second hydrophobic material is a carboxylic acid or a salt thereof represented by the following Chemical Formula 2: [Formula 1] In Chemical Formula 1, x is an integer of 10 to 20, [Formula 2] In Formula 2, y is an integer of 5 to 15, and z is an integer of 1 to 10.
[Claim 9]
The method of claim 8, wherein the hydrogel polymer has a moisture content of 30 wt% to 70 wt%.
[Claim 10]
The method of claim 8 , wherein a total weight of the first hydrophobic material and the second hydrophobic material is used in an amount of 0.01 to 1 part by weight based on 100 parts by weight of the hydrogel polymer.
[Claim 11]
The method of claim 8, wherein the hydrophobic composition further comprises water.
[Claim 12]
The method of claim 8 , wherein the pulverizing process is performed by a chopper.
[Claim 13]
The method of claim 8 , wherein the water-containing superabsorbent polymer particles have a particle diameter of 300 μm to 5000 μm.
[Claim 14]
The method of claim 8, wherein in the pulverized material, at least a portion of the first hydrophobic material and the second hydrophobic material is present on the surface of the water-containing superabsorbent polymer particles.
[Claim 15]
The method of claim 8, further comprising the step of forming a surface crosslinking layer on at least a portion of the surface of the superabsorbent polymer particles in the presence of a surface crosslinking agent.