KR20110111943A - Water absorbent resin with modified surface - Google Patents

Abstract

The present invention relates to an absorbent resin obtained by surface-modifying an absorbent crosslinked polymer having a range of fine particle sizes with a cationic polymer compound, and according to the present invention, an absorbent crosslinker having a range of fine particle sizes and a blood absorption By including a cationic high molecular compound useful in the present invention, it is possible to provide an absorbent resin which can improve the low absorption rate and low absorption power to the blood, which is a problem of the existing absorbent resin. According to the present invention, with respect to the powdered crosslinked base resin formed by internally crosslinking a partially neutralized acrylic acid monomer including an acid group with a first crosslinking agent, the base resin is further surface crosslinked with a second crosslinking agent to generate a crosslinked polymer. In the water absorbent resin formed by reacting with the cationic polymer compound on the surface of the crosslinked polymer, the crosslinked polymer formed by further surface crosslinking with the base crosslinking agent has a diameter of 30 to 300 μm based on the total weight of the crosslinked polymer. It is possible to provide a surface-modified absorbent resin, characterized in that 70 to 100% by weight.

Description

Water absorbent resin with modified surface

The present invention includes an absorbent crosslinkable polymer having a range of fine particle sizes and a cationic high molecular compound useful for the absorption of blood, thereby improving the low absorption rate and low absorption power of the existing absorbent resin into the absorbent resin. Invention.

Conventional techniques for improving the absorption rate have been mainly used to increase the surface area of the absorbent resin to reduce the particle size, to produce a granular form, or to form micropores in and out of the resin using a blowing agent.

As a method for forming micropores, foamed resin is prepared using liquid carbonate, imparted porosity by ultraviolet polymerization in the presence of carbonate, dispersed in an inert gas in a viscous monomer mixture and polymerized, or organic The method of superposing | polymerizing by mixing a solvent with a monomer was used. However, the method using the blowing agent requires a separate device for the addition and uniform dispersion of the blowing agent, there is a disadvantage that it is difficult to foam into a foam having a certain size of pores.

In addition, since the foamed and dried resin has a weak physical strength, a large amount of fine powder is generated in the grinding process, so that the ratio of fine powder is increased in the product, which is inconvenient to remove it. If the fines are not removed, the work environment worsens when the powder is applied to the sanitary or other finished product, and small particles may come out of the finished product.

On the other hand, in order to increase the absorbent power of the absorbent resin, a method of ionizing the ionic compound with the absorbent resin has been studied.

Japanese Laid-Open Patent Publication (JP2007-144423) includes certain absorbent resin particles (A) and a cationic polymer compound (B), and the cationic polymer compound (B) is substantially ionically bonded to the absorbent resin particles (A). Characterized in that.

Korea Patent Registration (KR10-854813) consists of chitosan, which is one or more gel-forming polysaccharides on the surface, and multi-component particles composed of water-swellable, acidic superabsorbent resin particles with microdomains with an average diameter of 1 nm to 200 μm. It provides a super absorbent material comprising a.

Korean Patent Laid-Open Publication (KR 2006-0135894) is characterized in that the sieved superabsorbent material of 300 to 600 ㎛ is coated with a first surface treatment agent which is an ion-interaction-enhancing agent and a second surface treatment agent which is a heat adhesive.

Korean Unexamined Patent Publication (KR2002-93080) is characterized by adding a cationic chitosan to the anionic absorbent gelling material.

The present invention includes a water absorbent crosslinking polymer having a range of fine particle size and a cationic high molecular compound useful for the absorption of blood in order to solve the problems of the existing water absorbent resin, thereby reducing the low An object of the present invention is to provide an absorbent resin capable of improving absorption rate and low absorption capacity.

According to the present invention, with respect to the powdered crosslinked base resin formed by internally crosslinking a partially neutralized acrylic acid monomer including an acid group with a first crosslinking agent, the base resin is further surface crosslinked with a second crosslinking agent to generate a crosslinked polymer. In the water-absorbent resin formed by reacting with a cationic high molecular compound on the cross-linking polymer surface,

The surface-modified absorbent resin is characterized in that the crosslinked polymer produced by further surface crosslinking of the base resin with the second crosslinking agent has a diameter of 30 to 300 μm with respect to the total weight of the crosslinked polymer. .

According to a preferred embodiment of the present invention, the crosslinked polymer produced by further surface crosslinking of the base resin with the second crosslinking agent has a diameter of 30 to 300 ㎛ with respect to the total weight of the crosslinking polymer, characterized in that 85 to 100% by weight Surface modified absorbent resin can be provided.

According to another preferred embodiment of the present invention, the cationic polymer compound is polymethacrylamide, polymethacrylamide aluminum sulfate, polymethacrylamide aluminum chloride, chitosan, chitosan-based aluminum sulfate, polysilica aluminum, polyaluminum chloride and Surface-modified absorbent resin, characterized in that at least one member selected from the group consisting of polyethyleneimine can be provided.

According to another preferred embodiment of the present invention, a surface modified absorbent resin can be provided, characterized in that the cationic polymer compound component is 0.01 to 10 parts by weight based on 100 parts by weight of the total content of the crosslinked polymer.

According to another preferred embodiment of the present invention, the surface-modified absorbent resin, characterized in that the acrylic acid monomer is represented by the following formula (1) can be provided.

[Formula 1]

R ¹ -COOM ¹

In Formula 1, R ¹ is a hydrocarbon group having 2 to 5 carbon atoms including an unsaturated bond, M ¹ is a hydrogen atom, a monovalent or divalent metal, an ammonium group or an organic amine salt.

According to another preferred embodiment of the present invention, the acrylic acid monomer is at least one member selected from the group consisting of acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids. Surface-modified absorbent resin can be provided.

According to another preferred embodiment of the present invention, the first 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, pentaerythritol tetraacrylate, triarylamine, ethylene glycol diglycidyl Le, the surface-modified water-absorbent resin, characterized in that at least one member selected from the group consisting of propylene glycol, glycerin, and ethylene carbonate, can be provided.

According to another preferred embodiment of the present invention, the second crosslinking agent is ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol Diglycidyl ether, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, propane diol, dipropylene glycol, polypropylene glycol, glycerin, polyglycerol, butanediol, heptanediol, hexane At least one surface selected from the group consisting of diol trimethylolpropane, pentaerythritol, sorbitol, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, iron hydroxide, calcium chloride, magnesium chloride, aluminum chloride, or iron chloride Modified absorbent resin can be provided All.

According to another preferred embodiment of the present invention, the surface-modified absorbent resin can be provided, characterized in that the average particle size of the absorbent resin is 150 to 850 ㎛.

As described above, by using an absorbent crosslinked polymer having a range of fine particle sizes and a cationic polymer compound useful for the absorption of blood, it is possible to improve the low absorption rate and low absorption capacity for blood, which is a problem of the existing absorbent resin. An absorbent resin can be provided.

1 is a view schematically showing the structure of a surface-modified absorbent resin according to an embodiment of the present invention.

Hereinafter, a preferred embodiment of the surface-modified absorbent resin according to the present invention will be described in detail with reference to the accompanying drawings, the same or corresponding components in the reference to the accompanying drawings are given the same reference numerals and overlapping therewith The description will be omitted.

Hereinafter, the absorption mechanism of the absorbent resin will be described before explaining the compound and reaction conditions for the surface-modified absorbent resin.

Absorption mechanism of the absorbent resin is due to the interaction between the penetration pressure due to the difference in electrical attraction force of the charge of the polymer electrolyte, the affinity between water and the polymer electrolyte, the expansion of the molecule due to the repulsive force between the polymer electrolyte ions, and the expansion inhibition due to crosslinking. Is dominated. That is, the absorbent capacity of the absorbent polymer depends on the affinity and molecular expansion described above, and the rate of absorption depends largely on the penetration pressure of the absorbent polymer itself. Thus, the molecular expansion and penetration pressure of the absorbent polymer chains depend on the crosslinking density and distribution introduced or the type of crosslinking agent.

In the present invention, crosslinking is mainly introduced into the water-absorbing highly powdered particles by co-crosslinking using a polyfunctional crosslinking agent such as a divinyl compound as the first crosslinking at the time of polymerization, and then re-agent on the surface using a diglycilyl ether compound or the like. By introducing bi-crosslinking (post-crosslinking), the external crosslinking density of the polymer particles could be made higher than the internal crosslinking density to increase the penetration pressure, thereby improving the absorption rate.

Absorbent resins are widely used materials such as crosslinked polyacrylates. However, these substances are not known to be useful when used in aqueous fluids such as blood and menstrual secretions. Menstrual secretions are known to contain many substances that tend to block polyacrylates. Such materials interact with the carboxyl groups of polyacrylates as metal ions. Such other substances in menstrual secretions are known to be proteins, fatty acids and cell debris.

1 is a view schematically showing the structure of the surface-modified absorbent resin of the core-shell-outer shell structure according to the present invention.

Referring to Figure 1, the surface-modified absorbent resin according to the present invention, the base resin with respect to the cross-linked base resin of the powder form formed by internally crosslinking a partially neutralized acrylic acid monomer containing an acid group with a first crosslinking agent, Is further crosslinked with a second crosslinking agent to form a crosslinked polymer, and in the absorbent resin formed by reacting with a cationic polymer compound on the surface of the crosslinker, the crosslinked polymer formed by further surface crosslinking with a second crosslinking agent It is a surface-modified absorbent resin, characterized in that 70 to 100% by weight having a diameter of 30 to 300 ㎛ relative to the total weight of the crosslinking polymer, more preferably produced by further surface crosslinking the base resin with a second crosslinking agent It is characterized in that the crosslinked polymer has a diameter of 30 to 300 ㎛ with respect to the total weight of the crosslinked polymer is 85 to 100% by weight It is surface modified absorbent resin.

Accordingly, the surface-modified absorbent resin 100 of the present invention includes an inner crosslinked core 110, an inner crosslinked and surface crosslinked shell 130, and an outermost portion 150 formed of a cationic polymer compound. The shell and the cationic polymer compound bind to each other by ionically bonding at the surface of the shell.

Acrylic acid monomer

Acrylic acid-based monomer which is a compound represented by the following formula (1) can be used in the preparation of the surface-modified absorbent resin of the present invention.

[Formula 1]

R ¹ -COOM ¹

In Formula 1, R ¹ is a hydrocarbon group having 2 to 5 carbon atoms including an unsaturated bond, M ¹ is a hydrogen atom, a monovalent or divalent metal, an ammonium group or an organic amine salt. More preferably, at least one acrylic acid monomer selected from the group consisting of acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts and organic amine salts of these acids is the core-shell-outer shell structure of the present invention. It can be used for the preparation of absorbent resin.

The acrylic acid monomer used in the present invention is used by partially neutralizing with an alkali such as sodium hydroxide, potassium hydroxide, ammonium hydroxide and the like. As alkali, sodium hydroxide which is inexpensive and nontoxic is more preferable.

The degree of neutralization of the acrylic acid monomer is preferably 40 to 80 mol%. In particular, the range of the degree of neutralization varies depending on the final physical properties, but if it is 80 mol% or more, most of the obtained polymer is dissolved in water, and at 40 mol% or less, the absorbency of the polymer is greatly reduced, and it is difficult to handle such as elastic rubber. Properties.

The concentration of the aqueous monomer solution is preferably 40 to 95% by weight or more. This is to avoid the need to remove the unreacted monomer after polymerization by using the gel effect phenomenon that occurs in the polymerization reaction of a high concentration aqueous solution.

The amount of water, which is a solvent, may be preferably used in a weight ratio of 1 to 5 times the content of acrylate, which is a monomer, and the amount of solvent may be determined in consideration of the heat of polymerization.

Initiator

Examples of the polymerization initiator include radical polymerization initiators such as potassium persulfate, sodium persulfate, ammonium persulfate, hydrogen peroxide, t-butylhydroperoxide, and hydrochloride salts of 2,2'-azobis-2-amidinopropane and 2-hydroxy- Photoinitiator of 2-methyl-1-phenyl-propan-1-one can be used. These and the reducing agent which accelerates | decomposes the decomposition of a polymerization initiator can be used together, and it can also be set as a redox-type initiator by combining both. As the reducing agent, sulfites such as sodium sulfite and sodium hydrogen sulfite, reducing metals such as ferrous salts, L-ascorbic acid and amines may be used alone or in combination of two or more, but are not limited thereto.

The concentration of the initiator is preferably 0.001 to 1.0 mol parts based on 100 mol parts of the total monomers. The initiator may be used together with a redox catalyst, and it is more preferable to use L-ascorbic acid.

First Bridge

The use of a crosslinking agent in the preparation of the absorbent polymer is necessary to maintain the physical properties of the resulting absorbent polymer. As a crosslinking method of the water absorbent resin, there are a simultaneous crosslinking method capable of introducing crosslinking between chains of the absorbent polymer during polymerization, and a postcrosslinking method of causing crosslinking of functional groups of the absorbent polymer after polymerization.

In this case, in order to reduce the decrease in absorbance due to the increase in the crosslinking density, when using a crosslinking agent having a suitable chain length, it was possible to prepare a water absorbent resin having high absorbency while maintaining excellent gel strength.

As crosslinking agents which can be crosslinked as the first crosslinking agent, α, β-unsaturated carboxylic acid monomers and any compound monomer capable of introducing a crosslinking bond during polymerization are possible. For example, 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, tri Ethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipentaerythritol pentaacrylate, glycerin tri (meth) acrylate, pentaerythritol tetraacrylate , Triarylamine, ethylene glycol diglycidyl ether, propylene glycol, glycerin, or ethylene carbo Sites for it is not may be used alone or in combination two, limited.

The content of the first crosslinking agent used is preferably 0.001 to 2.0 parts by weight based on 100 parts by weight of the acrylic acid monomer. If the content of the crosslinking agent is less than 0.001 part by weight, the absorption rate and the gel strength are too weak. If the content of the crosslinking agent is more than 2.0 parts by weight, the absorbency is too low, which is not preferable as the absorbent.

When the partially neutralized acrylic acid monomer containing an acidic group is internally crosslinked with a first crosslinking agent, a gel resin is obtained.

The grinders usable in the present invention for subdividing gel-type resins include shear granulation machines, impact crushers and high speed rotation crushers. Mills imparted with one or more grinders among cutting, shearing, impact and friction may be preferably used, in particular grinders with a cutting or shearing device imparted as a primary function, more preferably The grinder can be used where shearing and cutting effects are expected to be strong. Among the other pulverizers listed above, an apparatus having a grinding effect required by the shear formed by the plurality of rotary blades and the fixed blade is particularly preferred.

It is preferable that the average particle size of the granular gel resin is 1 to 10 mm.

The rotational speed of the rotary blade is preferably 3.0 to 200 m / sec, more preferably 5.0 to 150 m / sec.

The fine gel resin is heated and ground to produce a base resin powder. Drying by heating can be accomplished using a common drying apparatus or a heating furnace. As a typical example of the apparatus that can be used for such heat treatment, a grooved type mixing drier, a rotary dryer, a disk dryer, a fluid bed dryer, an airflow dryer, an infrared dryer, or the like can be used.

The method of subdividing the gel resin can be equally used for grinding after drying the fine gel resin. After drying the microgel resin, it can be pulverized to obtain a crosslinked base resin in powder form.

Second cross-link

The second crosslinking agent is, for example, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, or the like. Epoxy compounds, ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetraethylene glycol, propane diol, dipropylene glycol, polypropylene glycol, glycerin, polyglycerol, butanediol, heptanediol, hexanediol trimethyl Polyhydric alcohol compounds such as roll propane, pentaerythritol, or sorbitol, or polyhydric metal compounds such as hydroxides or chlorides such as calcium, magnesium, aluminum, or iron may be used alone or in combination of two or more thereof. no.

The second crosslinking agent content used is preferably 0.001 to 2.0 parts by weight based on 100 parts by weight of the dry neutralized base resin powder.

It is preferable that the crosslinked polymer produced by further surface crosslinking of the base resin with the second crosslinking agent has a diameter of 30 to 300 μm with respect to the total weight of the crosslinked polymer. Classified.

More preferably, the crosslinked polymer produced by further surface crosslinking of the base resin with the second crosslinking agent has a diameter of 30 to 300 µm based on the total weight of the crosslinked polymer.

It is possible to obtain a crosslinked polymer having a diameter of 30 to 300 μm based on the total weight of the crosslinked polymer, wherein the crosslinked polymer produced by further surface crosslinking with the second crosslinking agent is 70 to 100% by weight.

The relative amount of the first crosslinking agent and the second crosslinking agent is determined according to the chain length and type of the crosslinking agent.

Temperature and time of crosslinking polymerization reaction

In the case of the first crosslinking reaction, the reaction temperature is preferably 20 to 75 ° C, and the polymerization reaction is completed within 1 minute to 4 hours.

In the case of the second crosslinking reaction, the reaction temperature is preferably 90 to 160 ° C, and the polymerization reaction is completed within 1 minute to 4 hours.

Cationic Polymer Compound

By absorbing the absorbent resin and the material capable of ion bonding with the absorbent resin and coated on the surface it is possible to improve the absorption rate and absorbency. That is, it is ionized when contacted with water or moisture, and is absorbed by adding a substance capable of forming an ionic bond with the absorbent resin to (meth) acrylate-based absorbent resin which changes anionic when contacted with water or water. Speed and absorption could be improved. Similarly, the addition of a substance capable of forming an ionic bond to a polyethylenimine-based absorbent resin which is cationicly changed in contact with water or water can improve the absorption rate and the absorbency.

As the cationic polymer compound used to prepare the absorbent resin surface-modified with the cationic polymer compound of the present invention, polymethacrylamide, polymethacrylamide aluminum sulfate, polymethacrylamide aluminum chloride, chitosan, chitosan-based aluminum sulfate, poly Silica aluminum, polyaluminum chloride or polyethyleneimine may be used, and may be used alone or in combination of two or more, but is not limited thereto.

It is preferable to prepare one or two or more cationic polymer compounds in a solvent to prepare a cationic polymer compound solution, and to add a cationic polymer compound solution to prepare an absorbent resin surface-modified with the cationic polymer compound.

Referring to FIG. 1, the outermost portion 150 formed of a cationic polymer compound in which the cationic polymer compound is formed in contact with the surfaces of the crosslinked polymers 110 and 130 is the core 110 and the shell 130. It is preferably 0.01 to 10 parts by weight based on 100 parts by weight of the total content of the crosslinked polymer.

In addition, the average size of the absorbent resin 100 surface-modified with the cationic polymer compound composed of the core 110, shell 130 and the outermost portion 150 is preferably 150 to 850㎛.

100: surface modified absorbent resin
110: first crosslinking portion
130: first and second bridge
150: cationic polymer compound component

Claims (9)

For the crosslinked base resin in powder form formed by internally crosslinking a partially neutralized acrylic acid monomer including an acidic group with a first crosslinking agent, the base resin is further surface crosslinked with a second crosslinking agent to generate a crosslinked polymer, and the surface of the crosslinked polymer In the absorbent resin formed by reacting with a cationic high molecular compound,
The surface-modified absorbent resin, characterized in that 70 to 100% by weight of the crosslinked polymer produced by further surface crosslinking of the base resin with the second crosslinking agent has a diameter of 30 to 300 ㎛ with respect to the total weight of the crosslinking polymer. The surface modification according to claim 1, wherein the crosslinked polymer produced by further surface crosslinking with the base resin as the second crosslinking agent has a diameter of 30 to 300 µm based on the total weight of the crosslinked polymer. Absorbent resin. The group according to claim 1, wherein the cationic high molecular compound is made of polymethacrylamide, polymethacrylamide aluminum sulfate, polymethacrylamide aluminum chloride, chitosan, chitosan-based aluminum sulfate, polysilica aluminum, polyaluminum chloride and polyethyleneimine Surface-modified absorbent resin, characterized in that at least one selected from. The surface-modified absorbent resin according to claim 1, wherein the cationic polymer compound component is 0.01 to 10 parts by weight based on 100 parts by weight of the total amount of the crosslinked polymer. The surface-modified absorbent resin of claim 1, wherein the acrylic acid monomer is represented by the following Chemical Formula 1.
[Formula 1]
R ¹ -COOM ¹
In Formula 1, R ¹ is a hydrocarbon group having 2 to 5 carbon atoms including an unsaturated bond, M ¹ is a hydrogen atom, a monovalent or divalent metal, an ammonium group or an organic amine salt. The surface-modified absorbent of claim 1, wherein the acrylic acid monomer is at least one member selected from the group consisting of acrylic acid, methacrylic acid, and monovalent metal salts, divalent metal salts, ammonium salts, and organic amine salts of these acids. Suzy. The method of claim 1, wherein the first crosslinking agent is N, N'-methylenebisacrylamide, trimethylolpropane tri (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol (meth) acrylate, propylene glycol die (Meth) acrylate, polypropylene glycol (meth) acrylate, butanediol di (meth) acrylate, butylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, hexanedioldi ( Meta) acrylate, triethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipentaerythritol pentaacrylate, glycerin tri (meth) acrylate, Pentaerythritol tetraacrylate, triarylamine, ethylene glycol diglycidyl ether, propylene glycol, glycerin, And at least one member selected from the group consisting of ethylene carbonate. The method of claim 1, wherein the second crosslinking agent is ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerol polyglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, Ethylene glycol, diethylene glycol, propylene glycol, triethylene glycol, tetra ethylene glycol, propane diol, dipropylene glycol, polypropylene glycol, glycerin, polyglycerol, butanediol, heptanediol, hexanediol trimethylolpropane, A surface modified absorbent resin, characterized in that it is at least one member selected from the group consisting of pentaerythritol, sorbitol, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, iron hydroxide, calcium chloride, magnesium chloride, aluminum chloride, and iron chloride. The surface-modified absorbent resin according to claim 1, wherein the average particle size of the absorbent resin is 150 to 850 µm.

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