JPH11172129A - Production of highly water-absorbing resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition useful in a hygienic field, such as a sanitary product, a paper diaper or the like, a medical, a food industrial and an agricultural fields by mixing a highly water-absorbing resin with an organic functional material or the like, under a steam atmosphere. SOLUTION: This highly water-absorbing resin composition is obtained by mixing a highly water-soluble resin (e.g.; a crosslinked polyacrylic acid salt) with an organic functional material and/or an inorganic functional material under a steam atmosphere. As the highly water-absorbing resin, a dried powder and those containing water and/or an organic solvent are preferable. As the organic function material, at least one or more kinds selected from a surfactant and/or a highly polymeric compound, a radical chain inhibitor, a metal chelating agent and a reducing agent are preferable. As the inorganic functional material, one or more kinds selected from a reducing material, a metal chelating agent, a deodoring agent and a flow property improving agent are preferable. A supply pressure of the steam is preferably 100-1,000 kPa.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a superabsorbent resin composition, and more particularly to a method for producing a superabsorbent resin composition in which a functional substance is uniformly adhered to and penetrated by a superabsorbent resin. It is.

[0002]

BACKGROUND OF THE INVENTION Highly water-absorbing resins are used for sanitary products,
It is widely used in hygiene fields such as disposable diapers, medical fields, food industry fields, agricultural fields and the like. Such superabsorbent resins include partially crosslinked polyacrylates, starch-
Crosslinked acrylates, crosslinked polyethylene oxide, crosslinked poval, and the like are used.

[0003] In recent years, in order to improve water absorption performance, fluidity, weather resistance, and other various properties, a highly water-absorbent resin composition obtained by mixing various organic functional substances and / or inorganic functional substances with the above super-water-absorbent resin. Things have been proposed. As a method of mixing an organic functional substance and / or an inorganic functional substance with a superabsorbent resin, for example, the following method is disclosed. Japanese Patent Publication No. 2-30336 discloses that an aqueous solution of an organic functional substance is sprayed on a superabsorbent resin, the organic functional substance is dissolved in an organic solvent and the superabsorbent resin is immersed, or reverse phase suspension polymerization is performed. In the case of the resulting superabsorbent resin, a method of adding an organic functional substance to the polymerization dispersion is disclosed. JP-A-64-33149 discloses a method of adding a solution or dispersion of a functional substance to a water-containing or dried superabsorbent resin and mixing the same. And a method of dry blending and adding water. 6-9
No. 8306 discloses a method in which a water-insoluble functional substance is added as a water dispersion to a superabsorbent resin powder and mixed. However, in these methods, only the physical mixing or a state close to the physical mixing, the mixed state with the functional substance is not uniform, and the effect of the functional substance cannot be obtained, or the water content is increased to improve the uniformity. Increasing the amount causes a problem of formation of aggregates. In addition, since the adhesive force of the functional substance to the superabsorbent resin is weak, there is a problem that the functional substance is separated or dropped during transportation or use.

Japanese Patent Application Laid-Open No. 1-1113406 discloses a method in which a superabsorbent resin is mixed with a crosslinking agent having two or more functional groups, and the mixture is crosslinked by contacting with steam. However, in this method, the reaction of the crosslinking agent is simply and efficiently promoted on the surface of the superabsorbent resin.

Accordingly, an object of the present invention is to provide a method for efficiently producing a superabsorbent resin composition in which an organic functional substance and / or an inorganic functional substance are uniformly and firmly fixed to a superabsorbent resin. Is to do.

[0006]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that by mixing an organic functional substance and / or an inorganic functional substance under specific conditions into a superabsorbent resin, It has been found that the purpose can be achieved.

The present invention has been made on the basis of the above findings, and is characterized in that an organic functional substance and / or an inorganic functional substance are mixed with a super water-absorbing resin in a steam atmosphere. It is intended to provide a method of manufacturing a product.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for producing a superabsorbent resin composition of the present invention will be described in detail. The superabsorbent resin used in the present invention does not substantially dissolve in water, but absorbs water and swells. There is no particular limitation on such a superabsorbent resin. For example, a crosslinked polyacrylate, a crosslinked poly (vinyl alcohol / acrylate) copolymer, a starch-acrylate graft copolymer (crosslinked product) And a partially cross-linked polymer such as a polyvinyl alcohol-polymaleic anhydride graft copolymer cross-linked product having a carboxyl group or a salt thereof, and a partially cross-linked polysaccharide such as a carboxymethyl cellulose salt cross-linked product. . In particular, from the viewpoint of water absorption performance, it is preferable to use a crosslinked polyacrylate or a starch-acrylate graft copolymer (crosslinked product), and it is most preferable to use a crosslinked polyacrylate. In addition, these super absorbent polymers are
Each of them may be used alone or in combination of two or more.

In the above superabsorbent resin, "salt"
Examples thereof include alkali metal salts, alkaline earth metal salts and ammonium salts. Here, the degree of neutralization of the superabsorbent resin is 0.01 to 100% based on the number of moles of the acid groups in the superabsorbent resin, and is preferably 1%.
To 99%, and more preferably 40 to 95%.

The superabsorbent resin is not particularly limited in its form, and may be a dry powder (a dry powder) or a resin containing water and / or an organic solvent (a water-containing resin and / or a water-containing resin).
Or a state containing a solvent). Here, the “dry state” means a superabsorbent resin (hereinafter, referred to as “dry resin”) 100 containing no water (water content is 0% by weight).
It refers to a state where the water content relative to parts by weight is less than 1 part by weight. The “water-containing state” refers to a state where the water content is 1 part by weight or more based on 100 parts by weight of the dry resin. As such a water-containing state, usually, a state in which the water content is 1 to 100 parts by weight relative to 100 parts by weight of the dry resin is preferable, and
More preferably, the amount is from 50 to 50 parts by weight. Dry resin 10
If the water content relative to 0 parts by weight exceeds 100 parts by weight, coagulation or drying may be required, and the load of drying may increase. The `` solvent-containing state '' refers to the solid-liquid separation state of the suspension polymerization product obtained when preparing the superabsorbent resin by suspension polymerization, or after washing in the case of washing the superabsorbent resin with a solvent. It refers to a state containing an organic solvent such as a state containing the solvent. When such an organic solvent is contained, the energy cost required for removing the solvent increases, so that the content of the solvent is preferably small, and specifically, preferably 1 to 5 parts by weight based on 100 parts by weight of the dry resin.
0 parts by weight, more preferably 5 to 20 parts by weight. Among the forms of the superabsorbent resin, in particular, dry powder,
Or, the water content relative to 100 parts by weight of the dry resin is 1 to 100.
A water-containing state which is part by weight is preferred.

The average particle size of the particles of the superabsorbent resin is not particularly limited, and may be any one. However, it has an appropriate specific surface area because it exhibits the performance of the superabsorbent resin itself. From the viewpoint of obtaining the adhesion amount of the inorganic functional substance and / or uniform mixing with these functional substances, the thickness is preferably 1 to 1000 μm, and more preferably 10 to 8 μm.
00 μm, and more preferably 100 to 600 μm. The average particle size of the particles of the superabsorbent resin was defined as a particle size (D50) at which the cumulative fraction under the sieve reached 50%.

The organic functional substance used in the present invention and / or
Or the inorganic functional substance is attached to the superabsorbent resin,
It is fixed uniformly and firmly, and improves the function of the superabsorbent resin. In this specification,
"Functionality" means stability over time of gel strength related to urine resistance, light resistance, and the like; water absorption performance such as water absorption speed and liquid passage speed;
It refers to the ability to impart at least one of deodorant and deodorant properties; Therefore, the organic functional substance refers to an organic substance that imparts the above effects to the superabsorbent resin,
The above-mentioned inorganic functional substance means an inorganic substance which gives the above-mentioned effect to the superabsorbent resin.

The organic functional substance used in the present invention is an organic substance capable of imparting a desired function to the superabsorbent resin, and is particularly preferably water-soluble or water-dispersible. As such organic functional substances, as shown below, (i) an organic functional substance that improves the water absorption rate,
(Ii) an organic functional substance that improves the stability over time, (iii)
There are other organic functional substances that improve coloring, antibacterial properties, flowability and the like. These organic functional substances may be used alone or in combination of two or more.

(I) Surfactants and / or high molecular compounds are used as the organic functional substance for improving the water absorption rate. Examples of the surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenol ether, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene fatty acid ester,
Nonionic surfactants having an HLB of 7 or more such as polyoxyethylene oxypropylene block polymers; anionic surfactants such as fatty acid salts, alkyl naphthalene sulfonates, dialkyl sulfosuccinates, alkyl sulfates, and higher alcohol sulfates; alkyls Examples thereof include cationic surfactants such as amine salts and alkyl quaternary ammonium salts. Examples of the polymer compound include sodium polyacrylate, polyethylene glycol, polypropylene glycol, polyacrylamide, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, dextrin, sodium alginate, polyvinyl alcohol, water-soluble nylon,
Examples include polyethyleneimine and polyvinylpyrrolidone.

(Ii) As the organic functional substance for improving the stability over time, at least one selected from the group consisting of a radical chain inhibitor, a metal chelating agent and a reducing substance is used. The radical chain inhibitor may be a compound having a radical chain inhibiting ability, and examples thereof include conventionally known antioxidants, polymerization inhibitors, and radical scavengers. Among these radical chain inhibitors, water 1
One that dissolves at least 0.1 g per 00 g is preferable.
Examples of such a radical chain inhibitor include hydroquinone, p-methoxyphenol, benzoquinone,
Methylhydroquinone, t-butylhydroquinone, pyrogallol, gallic acid, methyl gallate, ethyl gallate, propyl gallate, tannic acid such as hydrolyzable tannin obtained from quintet or gallic, and condensed tannin obtained from Gambia and the like; Salts, lignin sulfonates, flavonoids such as quercetin and ellagic acid and their salts, phenolic compounds such as catechol and resorcinol and derivatives thereof, N-nitrosophenylhydroxyamine ammonium salts, amine compounds such as thiourea, etc. Is mentioned. Among them, bilogallol, gallic acid, gallic acid ester, tannic acid, flavonoids, thiourea and the like are preferable. These radical chain inhibitors can be used in combination with a metal chelating agent such as phosphoric acid or citric acid or a chain transfer agent such as mercaptans, lower fatty acid alcohols or carboxylic acids.

The metal chelating agent is selected from the group consisting of a hydrophobic part comprising a saturated or unsaturated hydrocarbon group having 6 or more carbon atoms and a group consisting of a carboxylic acid group, a sulfonic acid group, a hydroxyl group and a phosphoric acid group. A hydrophobic part comprising a hydrophilic part having at least one group and a hydrophilic part-containing compound;
Diketone derivatives; tropolone derivatives and the like are used. Here, examples of the compound containing a hydrophobic part and a hydrophilic part include polycarboxylic acid derivatives, hydroxycarboxylic acid derivatives, iminodiacetic acid derivatives, organic acid amide derivatives, N-acylated amino acid derivatives, phosphate ester derivatives, and phosphonic acid derivatives. Derivatives and polyvalent phosphonic acid derivatives.
Specifically, citric acid monoalkylamide, citric acid monoalkenylamide, citric acid monoalkyl ester,
Monoalkenyl citrate, alkylmalonic acid,
Alkenylmalonic acid, N-acylated glutamic acid, N-
Acylated aspartic acid, N-alkyl-N'-carboxymethyl aspartic acid, N-alkenyl-N'-carboxymethyl aspartic acid, monoalkyl phosphate, monoalkenyl phosphate or alkali metal salt or alkaline earth thereof Metal salts and the like.

Further, as the reducing substance, for example,
Mercaptan compounds such as cysteine, glutathione, thioglycolic acid and 2-mercaptoethanol; aldehydes such as formaldehyde and acetaldehyde; sugars;
Formic acid, oxalic acid and the like can be mentioned.

Among the above (ii) substances which improve the stability over time, metal chelating agents, especially monoalkylamide citrate, N-acylated sodium glutamate, especially N-acylated Sodium glutamate is preferred.

(Iii) Other organic functional substances include:
Various organic pigments such as insoluble azo pigments, carbon black,
Substances for coloring, such as coloring agents; substances for improving antibacterial properties, such as antibacterial agents; substances for improving fluidity, such as fluidizing agents, and the like are used.

The inorganic functional substance used in the present invention is an inorganic substance capable of imparting a desired function to the superabsorbent resin. Examples of such an inorganic functional substance include (i) an inorganic functional substance that improves the stability over time, (ii) an inorganic functional substance that improves the deodorant property, and (iii)
There are inorganic functional substances that improve fluidity. These inorganic functional substances may be used alone or in combination of two or more.

(I) Examples of the inorganic functional substance for improving the stability over time include reducing substances such as ionic inorganic compounds such as sodium sulfite, sodium thiosulfate and sodium hydrogen sulfite; and inorganic acids such as phosphoric acid. And the like. (Ii) Examples of the inorganic functional substance that improves deodorization include deodorants such as apatite, activated carbon, alumina, silica, and zeolite. (iii) Examples of the inorganic functional substance that improves fluidity include (hydrous / anhydrous) silicon dioxide main substances such as colloidal silica, white carbon, and ultrafine silica; hydrated alumina plate, and hydrated alumina fiber fiber. (Water-containing / anhydrous) alumina oxide-based material; rutile-type, anatase-type (water-containing / anhydrous) titanium oxide-based material; hydrotalcite,
Bentonite, kaolinite, kaolin, attapull guide, basic magnesium carbonate, lightweight or heavy calcium carbonate, soft or hard clay, talc, permiculate, barium sulfate, mica, diatomaceous earth, alumina, aluminosilicate, zeolite, calcium phosphate, zinc oxide, zirconia And the like. That is, as the inorganic functional substance, at least one selected from the group consisting of a reducing substance, a metal chelating agent, a deodorant, and a fluidity improver is used.

The above-mentioned organic functional substance and / or inorganic functional substance (hereinafter, both are collectively referred to as “functional substance”)
Is added to the superabsorbent resin and then mixed as described below. Here, the amount of the functional substance to be added is usually preferably 0.0001 to 100 parts by weight of the dry resin.
It is 30 parts by weight, more preferably 0.01 to 10 parts by weight. If the amount of the functional substance is less than 0.0001 part by weight, the effect of the addition may not be recognized,
Even when the amount exceeds the weight part, the amount of extra functional substances that do not adhere to the superabsorbent resin or adhere to the superabsorbent resin increases, and the amount of adhesion to the superabsorbent resin does not change so much, and the addition effect is hardly obtained.

The method of adding the above-mentioned functional substance is not particularly limited, but a method of adding it in a powder state or a method of adding it as an aqueous solution or aqueous dispersion is preferable. Here, when the method of adding as an aqueous solution is employed, the addition temperature is usually room temperature or lower or a temperature in a heated state, and preferably 10 to 90 ° C. Examples of the method of adding as an aqueous dispersion include a method of adding as a slurry, a suspension, and an emulsion. When the method of adding the aqueous solution or the aqueous dispersion is employed, the amount of water in the aqueous solution or the aqueous dispersion is preferably 1 to 1000 parts by weight, more preferably 1 to 1000 parts by weight, more preferably 1 part by weight of the functional substance. 10 to 500 parts by weight. If the water content is less than 1 part by weight, the viscosity of the aqueous solution or aqueous dispersion may increase, and handling may be difficult. If the water content exceeds 1000 parts by weight, the water content increases and agglomerates or excessive water content is removed. It is not preferable because utility cost and time are required. In addition, a method of adding as a solution of an organic solvent or a dispersion of an organic solvent can also be adopted.

The average particle size of the above-mentioned functional substance is not particularly limited and is appropriately selected depending on the method of adding the above-mentioned functional substance, but is usually 50 μm or less, preferably 10 μm or less. Further, the particle size ratio of the above-mentioned functional substance to the above-mentioned superabsorbent resin [(average particle diameter of the above-mentioned functional substance) / (average particle diameter of superabsorbent resin)] is preferably 0.0001 to 0.
2, more preferably 0.001 to 0.1.
By using a functional substance having the above average particle diameter within the above particle diameter ratio, the area of the portion where the functional substance adheres to the superabsorbent resin (attachment area) becomes sufficient, and the uniform and uniform area can be obtained. Can be fixed firmly. On the other hand, the average particle size of the functional substance is too large (more than 50 μm) or the particle size ratio is too large (more than 0.2).
Then, the adhesion area of the functional substance to the superabsorbent resin becomes small, and it becomes difficult to adhere to the superabsorbent resin, or the adhesion strength is reduced, and the functional substance is easily dropped off. In particular, when the method of adding the functional substance in a powder state and the method of adding the functional substance as a suspension or an emulsion are used, from the viewpoint of adhesion to the superabsorbent resin, the average particle size of the functional substance Alternatively, it is better that the particle size ratio is not too large. When the method of adding the functional substance as an aqueous solution is employed, the average particle diameter or the particle diameter ratio of the functional substance is preferably not too large from the viewpoint of easy dissolution. As described above, if the average particle size or the particle size ratio of the functional substance is too large, the adhesive force is reduced, and the amount of the functional substance must be increased to sufficiently adhere. This is uneconomical, and the effect of improving the functionality may not be sufficiently obtained.

In the production method of the present invention, the above-mentioned functional substance is mixed with the above-mentioned superabsorbent resin under a steam (steam) atmosphere. That is, it is essential that the superabsorbent resin be mixed with the functional substance under a steam atmosphere. Therefore, the supply of steam is performed before, during, or after the addition of the functional substance to the superabsorbent resin. Then, if necessary, heating is performed at the same time. The use of a steam atmosphere makes the water content in the highly water-absorbent resin uniform and prevents it from absorbing more water than necessary, preventing aggregation of the highly water-absorbent resins and facilitating diffusion of the functional substance. Thus, the functional substance can be uniformly and firmly fixed to the superabsorbent resin. Thus, the present invention aims at fixing a functional substance uniformly and firmly to a superabsorbent resin, and is different from the prior art aiming at a crosslinking reaction.

The supply pressure of the steam is not particularly limited, but is preferably 100 to 1000 kPa, more preferably 110 to 500 kPa, and particularly preferably 130 to 500 kPa.
It is 300 kPa. The supply pressure of the steam is 100k
If it is less than Pa, the superabsorbent resin may be in a state of high water content due to condensation of steam and agglomeration may occur, or if the superabsorbent resin becomes in a high water content, the energy cost required for water removal may increase, and if it exceeds 1000 kPa, The heat of the supplied steam may cause decomposition of the functional substance or the superabsorbent resin, which is not preferable.

The steam supply rate (supply rate per hour) is not particularly limited, but is usually 0.1 to 50 parts by weight, preferably 1 to 50 parts by weight, per 100 parts by weight of the superabsorbent resin. 20 parts by weight. If the steam supply rate is less than 0.1 parts by weight per hour, the effect of producing a steam atmosphere may not be obtained, and if it exceeds 50 parts by weight, the effect cannot be expected to be improved and it is economically disadvantageous. There is.

The supply amount of the steam is not particularly limited. Usually, the supply amount is 100 parts by weight of the superabsorbent resin.
0.1 to 600 parts by weight, preferably 1 to 300 parts by weight. If the supply amount of the steam is less than 0.1 part by weight, the adhesion of the functional substance to the superabsorbent resin may become non-uniform. May be.

The method of mixing the above superabsorbent resin and the above-mentioned functional substance is not particularly limited, but a method of mixing under a mechanical flow, a flow by a gas, or the like is preferable. As a device used when mixing under the above mechanical flow, a mixing device by mechanical force, specifically, a kneader, a Nauter mixer, a ball mill, a V-type mixer, a ribbon blender, a conical blender, a Henschel mixer, a Raikai , Paddle type mixer, screw type mixer,
Mixers such as a rotating disk type mixer and a high speed rotary paddle type mixer, and a stirring type dryer are exemplified. On the other hand, examples of an apparatus used when mixing under the flow of the gas include a fluidized bed dryer and a spray dryer. The addition of the functional substance and the mixing in the steam atmosphere may be performed using the same apparatus or different apparatuses.

The pressure in a mixing system (such as a mixing device) for mixing the superabsorbent resin and the functional substance is not particularly limited, but is preferably 7 to 1000 kPa, more preferably 40 to 500 kPa. And particularly preferably 10
0 to 300 kPa. The pressure in the mixing system is 7 kPa
If it is less than 1, the superabsorbent resin becomes highly water-containing due to condensation of steam and agglomeration occurs, or if the superabsorbent resin becomes highly water-containing, the energy cost required for water removal may increase. The heat of the supplied steam may cause decomposition of the functional substance or the superabsorbent resin, which is not preferable. Further, if it is out of the above range, it is not preferable because the equipment must be compatible with high vacuum or high pressure, which leads to an increase in cost.

The temperature of the mixture in the mixing system is not particularly limited, but is preferably 50 to 180 ° C., more preferably 70 to 155 ° C., and particularly preferably 80 to 135 ° C.
It is. If the temperature of the mixture in the mixing system is less than 50 ° C., steam may be strongly condensed and the water content of the superabsorbent resin may increase to cause agglomeration.
Further, thermal decomposition of the superabsorbent resin may occur, which is not preferable.

The mixing time for mixing the superabsorbent resin and the functional substance is not particularly limited, but is preferably within 12 hours, and more preferably 0.5 to 6 hours.
Time. It is not preferable that the mixing time exceeds 12 hours, because the effect does not change and economic disadvantage may occur.

According to the production method of the present invention, water is repeatedly condensed and evaporated on the surface of the highly water-absorbent resin particles by using steam, so that the treatment can be performed without absorbing the water inside the particles. It is possible to arbitrarily set the water content of the superabsorbent resin according to the combination of various conditions such as steam. Since the above-mentioned condensation and evaporation of water are phenomena occurring on the surface of the particles of the superabsorbent resin, the functional substance is also efficiently diffused and easily adhered to the whole. In addition, when the resin itself swells and contracts on the surface of the particles of the superabsorbent resin, the functional substance is fixed in the direction of the inside of the particles of the resin. As described above, according to the production method of the present invention, by combining various conditions such as steam at the time of mixing the highly water-absorbent resin and the functional substance under a steam atmosphere, the highly water-absorbent having an arbitrary water content Processing can be performed using resin. In addition, since the condensation and evaporation of the water and the swelling and shrinkage of the resin itself occur on the surface of the particles of the superabsorbent resin, the diffusion of the functional substance is facilitated, and the functional substance is uniformly dispersed in the superabsorbent resin. This makes it possible to efficiently obtain a strongly fixed superabsorbent resin composition. In the prior art, since water is used without using steam, the water is introduced and locally absorbed unevenly by the particles of the superabsorbent resin. In addition, when water is absorbed uniformly, the amount of used water increases, whereby the particles of the superabsorbent resin aggregate or energy is required to remove the water.

The superabsorbent resin composition obtained by the production method of the present invention has a functional substance fixed uniformly and firmly to the superabsorbent resin as described above.
Since it has excellent functions, it is widely used in various fields such as sanitary products, disposable diapers and other sanitary fields, medical fields, food industry fields, agricultural fields, and the like.

[0035]

The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited by these examples.

First, evaluation methods for the superabsorbent resin compositions obtained in the following Examples and Comparative Examples are described below. The superabsorbent resin composition was evaluated for each additional function (see Table 1 below). For super absorbent resin
If the functional substance for improving the aging stability is not uniformly attached, local deterioration occurs and the aging stability is reduced.
In addition, if the functional substance for improving the fluidity is not uniformly attached to the superabsorbent resin, a locally poor fluidity portion is generated and the overall fluidity is reduced. Therefore, the degree of uniform attachment of the functional substance to the superabsorbent resin can be determined by performing the evaluation for each additional function by the following evaluation method.

(Aging stability) L- at a concentration of 0.05% by weight
One part by weight of the superabsorbent resin composition is swollen with 45 parts by weight of a physiological saline solution containing ascorbic acid, put in a sample tube, placed in a high-temperature bath at 40 ° C., and swollen particles (gel) after 3 hours. ) Was observed, and the stability over time was evaluated according to the following criteria. A: The swollen particles have neither fluidity nor spinnability and show the same shape. ：: The swollen particles have some fluidity and spinnability, but show the shape as they are. Δ: The swollen particles do not dissolve, but have fluidity and spinnability, and the shape becomes unclear. X: Some of the swollen particles are dissolved and liquid, and half or more of the particles do not retain their shapes.

(Fluidity) The angle of repose, the degree of compression, the degree of spatula, and the degree of uniformity were measured with a powder tester (manufactured by Hosokawa Micron Co., Ltd.), which is a flowability measuring instrument, to obtain a fluidity index. The flowability was evaluated. 90-100: best 80-89: fairly good 70-79: good 60-69: normal 40-59: not very good 20-39: bad 0-19: very bad

(Fixing strength) 50 parts by weight of the obtained superabsorbent resin composition was charged into a wire mesh sieve having an opening of 88 microns,
The treatment was performed for 30 minutes using a low tap shaker, and the fixing strength (the degree to which the functional substance was fixed to the superabsorbent resin without falling off) was evaluated by visual observation.

Example 1 N- as an organic functional substance
0.1 parts by weight of acylated sodium glutamate (powder) [trade name: Amisoft HS-21, manufactured by Ajinomoto Co.] is added to 10 parts by weight of ion-exchanged water, dissolved at 60 ° C., and an aqueous solution of the functional substance is added. Prepared. A double-armed kneader [manufactured by Irie Seisakusho], a superabsorbent resin having a water content of 25 parts by weight based on 100 parts by weight of a dry resin [a crosslinked sodium polyacrylate, trade name: Poise SA-20, Kao Corporation] ))
100 parts by weight were added, and the aqueous solution of the functional substance prepared above was added. Next, 190 kPa steam was supplied into the kneader at a rate of 10 parts by weight per hour, and the same steam was further stirred for 1 hour while being supplied to the dryer jacket. Thereafter, drying was performed using a shelf-type vacuum dryer to obtain a superabsorbent resin composition. The stability over time of the obtained superabsorbent resin composition was evaluated. When the fixing strength of the superabsorbent resin composition was evaluated, almost no dropout of the functional substance was observed under the sieve. Further, the stability over time of the superabsorbent resin composition after the evaluation of the fixing strength was evaluated. The results of the evaluation of stability over time before and after the evaluation of the fixing strength are shown in [Table 1] below.

Example 2 A super-absorbent resin (dry powder) [Poise SA] was added to a double-armed kneader [manufactured by Irie Seisakusho].
-20] was added, and 0.01 part by weight of N-acylated sodium glutamate (powder) [Amisoft HS-21] as an organic functional substance was added. Next, 30
The mixture was stirred while supplying 0 kPa steam at a rate of 10 parts by weight per hour into the kneader. After stirring for 1 hour, a superabsorbent resin composition was obtained. The stability over time of the obtained superabsorbent resin composition was evaluated. When the fixing strength of the superabsorbent resin composition was evaluated, almost no dropout of the functional substance was observed under the sieve. Further, the stability over time of the superabsorbent resin composition after the evaluation of the fixing strength was evaluated. The results of the evaluation of stability over time before and after the evaluation of the fixing strength are shown in [Table 1] below.

Example 3 Na salt of citrate monoalkylamide as an organic functional substance (powder) [C18 of alkyl group] 0.1 parts by weight was dissolved in 10 parts by weight of ion-exchanged water An aqueous solution of the material was prepared. 100 parts by weight of a superabsorbent resin (dry powder) [Poise SA-20] was added to a double-armed kneader [manufactured by Irie Seisakusho], and the aqueous solution of the previously prepared functional substance was added. Next, 300
The kPa steam was supplied into the kneader at a rate of 10 parts by weight per hour, and the mixture was stirred while supplying the same steam to the kneader jacket. After stirring for 1 hour, a superabsorbent resin composition was obtained. The stability over time of the obtained superabsorbent resin composition was evaluated. When the fixing strength of the superabsorbent resin composition was evaluated, almost no dropout of the functional substance was observed under the sieve. Further, the stability over time of the superabsorbent resin composition after the evaluation of the fixing strength was evaluated. The results of the evaluation of stability over time before and after the evaluation of the fixing strength are shown in [Table 1] below.

Example 4 A super-absorbent resin (dry powder) [Poise SA] was added to a double-armed kneader (manufactured by Irie Seisakusho).
-20] was added, and 1 part by weight of a sodium salt of a monoalkylamide citrate (powder) [having 18 carbon atoms in the alkyl group] was added as an organic functional substance. Next, 190
The kPa steam was stirred while being supplied into the kneader at a rate of 10 parts by weight per hour. After stirring for 1 hour, a superabsorbent resin composition was obtained. The stability over time of the obtained superabsorbent resin composition was evaluated. When the fixing strength of the superabsorbent resin composition was evaluated, almost no dropout of the functional substance was observed under the sieve. Further, the stability over time of the superabsorbent resin composition after the evaluation of the fixing strength was evaluated. The results of the evaluation of stability over time before and after the evaluation of the fixing strength are shown in [Table 1] below.

[Example 5] A double-arm type kneader [manufactured by Irie Seisakusho] was added to a superabsorbent resin (dry powder) [Poise SA
-20] was added, and 1 part by weight of silicon oxide (trade name: Aerosil-200, manufactured by Nippon Aerosil Co., Ltd.) as an inorganic functional substance was added. Next, 190k
The Pa steam was stirred while being supplied into the dryer at a rate of 10 parts by weight per hour. After stirring for 1 hour, a superabsorbent resin composition was obtained. The fluidity of the obtained superabsorbent resin composition was evaluated. When the fixing strength of the superabsorbent resin composition was evaluated, almost no dropout of the functional substance was observed under the sieve. Furthermore, the fluidity of the superabsorbent resin composition after the fixing strength was evaluated was evaluated. The evaluation results of the fluidity before and after the fixing strength evaluation are shown in the following [Table 1].

Example 6 1 part by weight of silicon oxide [Aerosil-200] as an inorganic functional substance was dispersed in 10 parts by weight of ion-exchanged water to prepare a dispersion of the functional substance. 100 parts by weight of a superabsorbent resin (dry powder) [Poise SA-20] was added to a double-armed kneader [manufactured by Irie Seisakusho], and the previously prepared dispersion was added. Next, 30
Steam of 0 kPa was supplied into the kneader at a rate of 10 parts by weight per hour, and the same steam was further stirred while being supplied to the kneader jacket. After stirring for 1 hour, a superabsorbent resin composition was obtained. The fluidity of the obtained superabsorbent resin composition was evaluated. When the fixing strength of the superabsorbent resin composition was evaluated, almost no dropout of the functional substance was observed under the sieve. Furthermore, the fluidity of the superabsorbent resin composition after the fixing strength was evaluated was evaluated. The evaluation results of the fluidity before and after the fixing strength evaluation are shown in the following [Table 1].

[Comparative Examples 1 to 6] In Examples 1 to 6,
The same operation was performed except that steam was not supplied, to obtain a superabsorbent resin composition. The additional function of each of the obtained superabsorbent resin compositions was evaluated. In addition, when the fixing strength of these superabsorbent resin compositions was evaluated, in all cases, the falling off of the functional substance under the sieve was observed. Furthermore, the additional function of each superabsorbent resin composition after the evaluation of the fixing strength was evaluated. The evaluation results of the additional functions before and after the evaluation of the fixing strength are shown in [Table 1] below.

[0047]

[Table 1]

[0048]

According to the production method of the present invention, a highly water-absorbent resin composition in which an organic functional substance and / or an inorganic functional substance are uniformly and firmly fixed to a highly water-absorbent resin is efficiently produced. be able to.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor O ▲ saki ▼ Kazutomo 1334 Minato, Wakayama City, Wakayama Pref.

Claims (8)

[Claims] 1. A method for producing a superabsorbent resin composition, comprising mixing an organic functional substance and / or an inorganic functional substance in a steam atmosphere with the superabsorbent resin. 2. The supply pressure of the steam is 100 to 1
The method for producing a superabsorbent resin composition according to claim 1, wherein the pressure is 000 kPa. 3. The method for producing a superabsorbent resin composition according to claim 1, wherein the supply rate of the steam is 0.1 to 50 parts by weight per hour based on 100 parts by weight of the superabsorbent resin. 4. The method for producing a superabsorbent resin composition according to claim 1, wherein the superabsorbent resin is a dry powder. 5. The method for producing a superabsorbent resin composition according to claim 1, wherein the superabsorbent resin contains water and / or an organic solvent. 6. The method according to claim 1, wherein the organic functional substance is a surfactant and / or a polymer compound. 7. The superabsorbent resin according to claim 1, wherein the organic functional substance is at least one selected from the group consisting of a radical chain inhibitor, a metal chelating agent and a reducing substance. A method for producing the composition. 8. The method according to claim 1, wherein the inorganic functional substance is at least one selected from the group consisting of a reducing substance, a metal chelating agent, a deodorant, and a fluidity improver. A method for producing a superabsorbent resin composition.