JP2002253961A - Water absorption material and production method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biodegradable water a absorption material which has excellent water absorptivity to a divalent or lower cationic aqueous solution and excellent urine resistance, and a production method therefor. SOLUTION: A compound consisting of galactomannan and polyvalent metallic ions is treated with a compound having an epoxy group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to sanitary materials such as disposable diapers (disposable diapers), sanitary napkins, incontinence pads, etc., as well as freshness retaining materials such as drip sheets, soil improving materials and seed covering materials. Agricultural and horticultural materials such as agricultural chemicals and fertilizer disintegration aids, concrete curing materials, sealing materials, solidification materials for sludge and sludge, portable toilets, waste disposal bags, cool insulation materials, sweat-absorbing sheets and other toiletry supplies, wound dressing materials The present invention relates to a biodegradable water-absorbing material suitably used for medicines such as compresses, medical supplies and the like, and a method for producing the same.

[0002]

2. Description of the Related Art A water-absorbent resin is a resin capable of absorbing water of several tens to several thousand times its own weight, such as sanitary products, paper diapers, breast milk pads, disposable rags and other hygiene products, dressing materials for wound protection, Medical supplies such as medical underpads, cataplasms, pet seats, portable toilets, gel fragrances, gel deodorants, sweat-absorbing fibers, disposable warmers and other daily necessities,
Toiletries such as shampoos, gels for setting, moisturizers, etc., water retention materials for agriculture and horticulture, cut flower life prolonging agents, floral foam (fixing material for cut flowers), nursery floors, hydroponics, vegetation sheets, seed tape Agriculture, horticultural supplies, food tray freshness preserving materials, such as fluid seeding, dew condensation prevention agricultural sheets,
Food wrapping materials such as drip-absorbent sheets, cold insulation materials, transportation materials such as water-absorbent sheets for transporting fresh vegetables, building materials for preventing dew condensation, civil engineering, sealing materials for construction, anti-sedimentation materials for shield method, concrete mixing Materials for civil engineering and construction such as chemicals, gaskets, packing, sealing materials for electronic devices such as optical fibers, waterproof materials for communication cables, materials for electric devices such as inkjet recording paper, coagulants for sludge, dehydration of gasoline and oils, It is used in a wide range of fields, such as water treatment agents such as water removers, printing pastes, water-swellable toys, and artificial snow. In addition, it is expected to be used for sustained-release fertilizers, sustained-release pesticides, sustained-release drugs, and the like by utilizing the sustained-release properties of the chemicals. Further, it is expected to be used as a humidity control agent utilizing its hydrophilicity and as an antistatic agent utilizing its charge retention.

[Prior art relating to water-absorbing resin] Examples of the water-absorbing resin used in such applications include:
Cross-linked partially neutralized polyacrylic acid (JP-A-55-84304, U.S. Pat. No. 4,462,501), starch-acrylonitrile copolymer partially hydrolyzed product (JP-A-46-43995), starch-acrylic acid graft copolymer Polymer (JP-A-519125468), hydrolyzate of vinyl acetate and acrylate copolymer (JP-A-
52-14689) Copolymerized crosslinked product of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid (European Patent 006818)
No. 9), a crosslinked product of a cationic monomer (US Pat. No. 4,906,717)
No.) Crosslinked isobutylene-maleic anhydride copolymer (US Pat. No. 4,389,513) is known.

[0004] Currently, water-absorbent resins on the market are mainly polyacrylic acid-based resins that do not have biodegradability, and the water-absorbing material has a very high deionized water absorption capacity of several hundred to 1,000 times. ing. However, the sodium chloride water absorption capacity of these water-absorbing materials, for example, the physiological water (0.9% by mass sodium chloride water) water absorption capacity is only about 50 to 75 g / g when quoted from numerical values in catalogs and the like. /Five~
Most have only about 1/10. Further, for an aqueous solution having a high sodium chloride concentration, for example, for seawater, 20 to
It has a water absorption capacity of only about 25 g / g.

Further, since these water-absorbent resin compositions do not have decomposability, disposal after use is a problem. At present, these water-absorbent resins are incinerated at the time of disposal and landfilled.However, in the incinerator method, in addition to damage to furnace materials due to heat generated during incineration, It is pointed out that it causes warming and acid rain. Furthermore, when incinerating used paper diapers with a high moisture content, the temperature inside the furnace decreases when the incinerator is put in,
Since the combustion atmosphere is likely to cause deterioration of the furnace material and dioxin, the burden on the exhaust gas treatment equipment at the subsequent stage is increased, and an exhaust gas treatment equipment with higher performance is required. In the landfill method, there are problems that the volume of plastic is bulky, the ground does not stabilize because it does not rot, and there is a major problem that there is no longer a place suitable for landfill. That is, these resins are poorly decomposable and exist semipermanently in water and soil, which is a very serious problem in view of environmental conservation in waste treatment.

[Technical background of water-absorbing resin having biodegradability] On the other hand, biodegradable polymers have recently attracted attention, and it has been proposed to use this as a water-absorbing resin.
Examples of the biodegradable water-absorbing resin used in such applications include cross-linked polyethylene oxide (Japanese Patent Laid-Open No. 6-157795), cross-linked polyvinyl alcohol, cross-linked carboxymethyl cellulose (US Pat. No. 4,650,716). , Polyamino acid cross-linked product (Japanese Unexamined Patent Publication
JP-A-224163, JP-A-7-309943, JP-A-8-59820, JP-A-8-504219, JP-A-9-169840, etc., and a galactomannan-metal ion crosslinked product (JP-A-8-59891, Fairness 3-66
321 and JP-A-56-97450) are known.

As a water-absorbing material having biodegradability, a water-absorbing material comprising galactomannan and titanium or zirconium (US patent)
No. 5,532,350) and a polysaccharide containing cis-1,2-diol and sodium borate (US Pat. No. 4,334,461). JP-A-8-59891 discloses a water-absorbing material obtained by crosslinking galactomannan or a derivative thereof with boron ions, titanium ions, zirconium ions, or aluminum ions.

[0008]

The water-absorbing material comprising the above-mentioned polysaccharide has a physiological saline absorption capacity of 30 to 70 times and is excellent in salt resistance, but it absorbs and absorbs artificial urine after water absorption and swelling. The gel disintegrated over time. In addition, the water-absorbing material composed of a crosslinked body of galactomannan showed a high water absorption capacity stably for a long time with physiological saline, but the gel after water absorption and swelling with artificial urine with time Collapsed. Therefore, in order to use these water-absorbing materials for water-absorbing articles such as sanitary goods, it is necessary to maintain the water absorption ratio and to impart urine resistance.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned conventional problems and to provide a biodegradable, water-absorbing agent having excellent ability to absorb a divalent or less cationic aqueous solution, artificial urine, and urine resistance. Material and a method for producing the same.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, by heat-treating an epoxy compound to a galactomannan-based water-absorbing material,
The inventors have found that this object can be achieved, and have reached the present invention.

That is, a first aspect of the present invention is to provide a water-absorbing material characterized in that galactomannan is formed of a gel cross-linked by a polyvalent metal ion and an epoxy compound. Preferably,
Both the water absorption of the 0.9% by mass aqueous sodium chloride solution and the water absorption of the artificial urine are at least 20 times their own weight.
Further, the second aspect of the present invention is characterized in that, after dissolving and swelling galactomannan, a polyvalent metal ion is added to form a crosslinked body, and thereafter, an epoxy compound is mixed with the crosslinked body and heat-treated. The gist is a method of manufacturing a water absorbing material.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The water-absorbing material of the present invention comprises a gel in which galactomannan is crosslinked with a polyvalent metal ion and an epoxy compound.

The galactomannan used in the present invention is at least 50% by mass of unmodified galactomannan, which can be crosslinked with a polyvalent metal ion, and which is treated with an epoxy compound to absorb a divalent or less cationic aqueous solution. It is not particularly limited as long as it gives artificial urine absorption capacity and urine resistance. For example, locust bean gum and guar gum can be used, but guar gum is preferred because of its low cost. These may be cross-linked with polyvalent metal ions,
One or more galactomannan derivatives may be mixed with the unmodified galactomannan before crosslinking. In this case, examples of the galactomannan derivative that can be mixed with all galactomannan include carboxymethyl galactomannan, carboxymethyl hydroxypropyl galactomannan and hydroxypropyl galactomannan, and one or more galactomannan derivatives selected from these groups. It may be added in a range of 50% by mass or less of the total galactomannan and then crosslinked with a polyvalent metal ion. However, if a carboxyl group is contained in the structure of the water-absorbing material, the cost increases, while the mixing ratio of these is preferably 10% by mass or less of the total galactomannan, more preferably 5% by mass.
% By mass or less.

The molecular weight of galactomannan is preferably 10,000 or more, more preferably 50,000 or more. Molecular weight 1
When the molecular weight is less than 0000, the gel is not formed even when crosslinked with a polyvalent metal ion, which is not suitable.

The polyvalent metal ion which functions as a crosslinking agent in the water-absorbing material of the present invention includes boron ion, titanium ion, zirconium ion, aluminum ion, yttrium ion, cerium ion, etc., but is inexpensive and has high safety. Accordingly, one or a combination of two or more of boron ions, titanium ions and zirconium ions can be mentioned.

The content of these polyvalent metal ions in the water-absorbing material is preferably from 2 to 2,000 mmol, particularly preferably from 5 to 1,000 mmol, per kg of guar gum.

Further, the water absorbing material of the present invention is characterized in that an epoxy compound also contributes as a crosslinking agent. Such an epoxy compound is selected from compounds capable of crosslinking with the hydroxyl group of guar gum, such as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, glycerol polyglycidyl ether, Methylol propane polyglycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, dipropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and the like include diglycerol polyglycidyl. Ether, ethylene glycol diglycidide Ethers such as is preferred.

The above-mentioned water-absorbing material is excellent in the ability to absorb a divalent or less cationic aqueous solution, an artificial urine-absorbing ability, urine resistance and biodegradability, and is preferably a 0.9% by mass aqueous sodium chloride solution. Both have a water absorption capacity of 20 times or more of their own weight.

The artificial urine referred to here generally includes potassium chloride, sodium sulfate, ammonium dihydrogen phosphate,
Diammonium hydrogen phosphate, calcium chloride, magnesium chloride, etc. are dissolved in ion-exchanged water.
The artificial urine used to represent the water absorbing ability of the water absorbing material of the present invention has the following composition.

That is, 2.00 g of potassium chloride, 2.00 g of sodium sulfate, 0.85 g of ammonium dihydrogen phosphate, 0.15 g of diammonium hydrogen phosphate, 0.19 g of calcium chloride,
A solution prepared by dissolving 0.23 g of magnesium chloride in 1 L of ion-exchanged water.

The amount of water absorption referred to herein is a value obtained by measurement according to the following method. That is, 1 g of water-absorbing material is put in a 250 mesh nylon tea bag, and 1 L
The tea bag was immersed in the water-absorbing liquid for 1 hour, the tea bag was pulled out, and the water was drained for 10 minutes. The amount of water absorbed by the water-absorbing material is defined as the mass of the tea bag containing no water-absorbing material soaked in water for 1 hour, and the mass of the water-absorbing material before swelling is calculated as The value obtained by dividing the value obtained by subtracting the mass of the blank by the mass of the water-absorbing material before swelling was defined as the water absorption (g / g resin).

Next, a second manufacturing method of the present invention will be described. The galactomannan used in the present invention and the derivative to be added as required are as described above, and in the production method of the present invention, this is first dissolved and swelled. The swelling concentration of galactomannan in water is not particularly limited as long as galactomannan can uniformly swell in water and can easily form a gel at the time of crosslinking with a polyvalent metal ion. It is from 15% by mass to 15% by mass, more preferably from 0.5% by mass to 10% by mass. The swelling temperature at this time is not particularly limited as long as galactomannan can swell and does not cause a decrease in molecular weight due to thermal decomposition, but is preferably 5 ° C to 80 ° C, more preferably 15 to 6 ° C.
0 ° C.

Next, a polyvalent metal ion is added to the swollen galactomannan for crosslinking. The polyvalent metal ion to be used is as described above, and the form of the boron ion, titanium ion, and zirconium ion is not particularly limited, but the boron ion is preferably an aqueous solution of sodium tetraborate decahydrate. The titanium ion is preferably an alkoxide compound, and Tyzor131, TyzorTE (titanium IV triethanolaminate isopropoxide), TyzorAA (titanium IV diisopropoxide)
Bisacetylaminate), TyzorGBA, TyzorTOT (titanium tetra-2-ethylhexoxide), TyzorTPT
(Titanium IV tetraisopropoxide) (DuPont), TAT (Titanium IV isopropoxyoctylene glycolate) (Nissau), TEAT (Titanium IV bisteroethanol aminate diisopropoxide), TAA (Titanium IV) Bisacetylacetonate diisopropoxide) (Mitsubishi Gas Chemical Co., Ltd.) and the like. Examples of the zirconium ion source include zirconium chloride and zircosol AC-7 (zirconyl ammonium carbonate) (manufactured by Nutex). These have different stability depending on the conditions such as the solvent used and pH, and may be appropriately selected.

The concentration of metal ions used for crosslinking the galactomannan sol is preferably 10 to 2000 mmol, more preferably 30 to 1000 mmol, per 1 kg of the total galactomannan mass with respect to boron ions. The trivalent or higher polyvalent metal ion other than boron differs depending on the type and form of the metal ion.
It is preferably from 1 to 500 mmol, particularly preferably from 5 to 200 mmol, per kg.

The temperature at which a crosslinked gel of galactomannan and the polyvalent metal ion is formed is not particularly limited, but is preferably 5 to 90 ° C. in order to promote the reaction, and 10 to 50 ° C.
Is more preferred.

In the present invention, a crosslinked gel can be obtained from a galactomannan sol and a polyvalent metal ion by any method as long as the sol and the crosslinker are uniformly mixed.
One-axis kneaders, two-axis kneaders, kneaders and the like can be mentioned.

In the present invention, it is necessary to further crosslink the gel crosslinked with polyvalent metal ions with an epoxy compound. The epoxy compound used here is as described above. As commercially available products, Denacol EX421, Denacol EX521, Denacol EX810, Denacol EX614B, Denacol EX313 (manufactured by Nagase Kasei Kogyo Co., Ltd.) and the like are preferably used.

The amount of the epoxy compound used is preferably 0.01% by mass to 10% by mass of the total galactomannan, and more preferably 0.01% by mass to 6% by mass. If the amount is too large, it is not preferable because the produced water-absorbing material has a reduced water absorption and affects biodegradability. On the other hand, when the amount is too small, it is difficult to improve the urine resistance and the hand and to obtain the improvement effect.

As a method for adding the epoxy compound, for example, a water absorbing material once cross-linked and dehydrated by a polyvalent metal ion may be dispersed in an organic solvent, and then the epoxy compound may be mixed, but the mixing method is particularly limited. Not something. Among various mixing methods, a method in which an epoxy compound dissolved in water and an organic solvent is directly sprayed and dropped onto the once crosslinked water-absorbing material, if necessary, may be used.

In the production method of the present invention, it is necessary to carry out a heat treatment when crosslinking with the added epoxy compound. The temperature of the heat treatment depends on the type of the crosslinking agent,
Although it depends on the type of the solvent used, it is preferably from 110 ° C to 200 ° C, more preferably from 130 ° C to 180 ° C. If the treatment temperature is 110 ° C. or lower, the reaction with galactomannan is not sufficiently performed, and the desired performance of the resulting water-absorbing material cannot be sufficiently obtained, and the urine resistance decreases. Also,
When the temperature exceeds 200 ° C., the galactomannan crosslinked product is deteriorated, and the performance such as water absorption performance, coloring, and urine resistance is lowered.

The heating time in the crosslinking with the epoxy compound depends on the type of the crosslinking agent, the intended water absorption performance, the temperature and the type of the solvent, but is preferably 5 minutes or more and 5 hours or less, more preferably 10 minutes or more and 3 hours or less. preferable. The heat treatment can be performed in a solvent or a dryer.

When crosslinking with an epoxy compound, a catalyst may be used as necessary to accelerate the reaction. As the catalyst, pyridine, 2-methylimidazole, triethanolamine and the like are suitably used.

The addition amount of the above-mentioned catalyst is not particularly limited as long as the reaction of the epoxy compound is promoted. Usually, however, it is added in an amount of 1 to 10% by mass, preferably 2 to 8% by mass based on the epoxy compound. Is good.

In the production method of the present invention, after galactomannan is cross-linked with a polyvalent metal ion, an epoxy compound is further added and heat treatment is performed to perform cross-linking. It is preferable that after the dehydrated and dried cross-linked body prepared by the above, the following epoxy compound is added and heated to perform cross-linking. A polyvalent metal ion may be added simultaneously with the addition of the epoxy compound, or crosslinking with the polyvalent metal ion may be performed twice.

The method of drying the gel crosslinked with the polyvalent metal ion and the epoxy compound in the present invention may be any method other than a method that reduces the water absorption capacity, water absorption speed and gel strength after water absorption. It doesn't matter,
In addition to room temperature drying, heating drying, freeze drying, drying under reduced pressure, etc., the water in the gel is also converted to monohydric alcohols having 1 to 5 carbon atoms (such as methanol, ethanol and isopropanol) and ketones having 3 to 6 carbon atoms ( There is a method in which a solvent such as acetone or a mixture thereof is added to the gel in an amount of 30% or more based on the water content of the gel, and the mixture is replaced with these solvents.

The shape of the dried water-absorbing material obtained by the production method of the present invention is not particularly limited, but may be various shapes according to the purpose of use. For example, it may be in the form of granules, sheets, films, powders, pieces, flakes, rods, fibers and the like. These shapes may be formed after drying, or at the time of drying, the gel may be placed in a forming device having such a shape and dried.

The thus obtained water-absorbing material of the present invention may further contain, if necessary, a deodorant, a fragrance, various inorganic powders, a foaming agent, a pigment, a dye, an antibacterial agent, a foaming agent, a hydrophilic short fiber, Agents, adhesives, surfactants, fertilizers, oxidizing agents, reducing agents,
Water, salts and the like may be added to impart various functions to the water-absorbing material. Examples of the inorganic powder include substances inert to aqueous liquids and the like, for example, fine particles of various inorganic compounds and fine particles of clay minerals. The inorganic powder,
Those having a suitable affinity for water and insoluble or poorly soluble in water are preferred. Specifically, for example, metal oxides such as silicon dioxide and titanium oxide, silicic acids (salts) such as natural zeolite and synthetic zeolite, kaolin, talc,
Clay, bentonite and the like can be mentioned. Among them, silicon dioxide and silicic acid (salt) are more preferable, and silicon dioxide and silicic acid (salt) having an average particle diameter of 200 μm or less as measured by the Coulter counter method are more preferable.

The amount of the inorganic powder used in the water-absorbing material of the present invention depends on the combination of the water-absorbing material and the inorganic powder.
The amount may be in the range of 0.001 to 10 parts by mass, more preferably in the range of 0.01 to 5 parts by mass with respect to 100 parts by mass of the water absorbing material. The method of mixing the water-absorbing material and the inorganic powder is not particularly limited. For example, a dry blending method, a wet mixing method, or the like can be used, but a dry blending method is preferably used.

The water-absorbing material of the present invention is made into an absorbent article by combining it with a fibrous material such as pulp. Examples of the absorbent articles include sanitary materials (body fluid absorbent articles) such as disposable diapers, sanitary napkins, incontinence pads, wound protection materials, wound healing materials; absorbent articles such as urine for pets; water-retaining materials for construction materials and soil; Civil engineering materials such as waterproofing materials, packing materials, gel blisters, etc .; Food products such as drip absorbing materials, freshness preserving materials, and cold insulators; Various industrial products such as oil / water separating materials, anti-condensation materials, and coagulating materials; Agricultural and horticultural articles such as water retention materials such as plants and soil; and the like, but are not particularly limited. In addition, for example, a disposable diaper includes a back sheet (back surface material) made of a liquid-impermeable material, a core layer containing the water-absorbent resin of the present invention, and a top sheet (surface material) made of a liquid-permeable material. They are laminated in this order and fixed to each other, and are formed by attaching gathers (elastic portions), so-called tape fasteners, and the like to the laminate. Further, the disposable diaper also includes pants with a disposable diaper used when disciplining urination and defecation for infants.

As long as the properties of the water-absorbing material of the present invention are not lost, monosaccharides,
Organic compounds such as chelating agents, inorganic salts, colloidal silica, layered silicate, zeolite, talc, white carbon, ultrafine silica, and inorganic compounds such as titanium oxide powder may be added. In addition, plasticizers, oxidizers, antioxidants, reducing agents, ultraviolet absorbers, antibacterial agents, fungicides, fertilizers,
Perfumes, deodorants, deodorants, pigments and the like may be mixed. In some cases, a crosslinking retarder may be added.

[0041]

Next, the present invention will be described more specifically with reference to examples. The measuring methods used in the examples and the comparative examples are as follows. (a) Physiological saline water absorption The water absorption was measured using a 0.9% by mass aqueous sodium chloride solution by the tea bag method. That is, 1 g of a water-absorbing material is placed in a 250-mesh nylon tea bag,
A tea bag was immersed in a 3% by mass aqueous sodium chloride solution for 3 hours, the tea bag was pulled out, and after draining for 10 minutes, the mass was measured. The amount of water absorbed by the water-absorbing material is defined as the mass of the tea bag containing no water-absorbing material soaked in water for 1 hour, and the mass of the water-absorbing material before swelling is calculated as The value obtained by dividing the value obtained by subtracting the mass of the blank by the mass of the water-absorbing material before swelling was defined as the water absorption (g / g resin).

(B) Amount of artificial urine absorbed by water 2.00 g of potassium chloride, 2.00 g of sodium sulfate, 0.85 g of ammonium dihydrogen phosphate, and 0.8 g of diammonium hydrogen phosphate.
15g, calcium chloride 0.19g, magnesium chloride 0.23g
Was dissolved in 1 L of ion-exchanged water, and the amount of artificial urine absorbed was measured in the same manner as in (a) except that the solution to be absorbed was used.

(C) Urine resistance test The gel which absorbed 30 times artificial urine with respect to the water-absorbing material was allowed to stand,
After 3 hours, the state of the gel after 20 hours was evaluated by touch. The state where no slip was felt in the gel: 、, the state where the gel felt a slight slip: △, the state where the gel felt a slip: × was evaluated.

Example 1 A 2% by mass aqueous solution of guar gum (manufactured by Sanei Pharmaceutical Trading Co., Ltd.) was swollen to prepare a sol solution. After swelling for 30 minutes, the sol liquid 200m
l TEAT (titanium IV bisteroethanol aminate diisopropoxide) (Mitsubishi Gas Chemical Co., Ltd.) solution as titanium ion content 30 mmol / kg guar gum, sodium tetraborate decahydrate aqueous solution as boron ion content The guar gum was added at a concentration of 500 mmol per kg, and was sufficiently crosslinked while being mixed with a blender. The same amount of ethanol as this gel was added, and the gel was crushed with a blender and dehydrated. The dehydrated crosslinked guar gum was washed, filtered and dried. To 2 g of this crosslinked guar gum, 40 ml of 1-butanol and Denacol EX421 (manufactured by Nagase Kasei Kogyo Co., Ltd.)
5% by weight based on guar gum, 2-methylimidazole
0.025% by mass was added and reacted at 130 ° C. for 3 hours. The solid after the reaction was washed with ethanol and dried to obtain a water-absorbing material of the present invention, and its water-absorbing ability and urine resistance were measured. The results are shown in Table 1.

[0045]

[Table 1]

Example 2 Zircosol AC-7 was used in place of TEAT used in Example 1.
A water-absorbing material was produced in the same manner as in Example 1 except that (manufactured by Nutex) was used (converted as zirconium ion content), and the water-absorbing performance was measured. The results are shown in Table 1.

Example 3 A 2% by weight aqueous solution of guar gum (manufactured by Sanei Chemical Trading Co., Ltd.) was swollen to prepare a sol solution. After swelling for 30 minutes, the sol liquid 200m
To the l, add a TEAT (Mitsubishi Gas Chemical Co.) solution as a titanium ion content of 15 mmol / kg of guar gum, and add an aqueous solution of sodium tetraborate decahydrate to a boron ion content of 500 mmol / kg of guar gum, and blender And sufficiently crosslinked. The same amount of ethanol as this gel was added, and the gel was crushed with a blender. 1 kg of guar gum with TEAT solution as titanium ion content
The reaction was carried out at room temperature for 20 minutes. The crosslinked guar gum after the reaction was washed, filtered and dried. To 2 g of this crosslinked guar gum, 40 ml of 1-butanol and Denacol EX42
1 (manufactured by Nagase Kasei Kogyo Co., Ltd.) at 5% by mass based on guar gum,
0.025% by mass of 2-methylimidazole was added,
Reacted for hours. The solid after the reaction was washed with ethanol and dried to obtain a water absorbing material of the present invention, and the water absorbing performance was measured. The results are shown in Table 1.

Example 4 Zircosol AC-7 was used in place of TEAT used in Example 3.
A water-absorbing material was produced in the same manner as in Example 3 except that the content of zirconium ions was changed to 250 mmol, and the water-absorbing performance was measured. The results are shown in Table 1.

Comparative Example 1 A 2% by weight aqueous solution of guar gum (manufactured by Sanei Chemical Trading Co., Ltd.) was swollen to prepare a sol solution. After swelling for 30 minutes, the sol liquid 200m
To the l, add a TEAT solution as a titanium ion content of 30 mmol per 1 kg of guar gum, and add an aqueous solution of sodium tetraborate decahydrate to a boron ion content of 500 mmol per 1 kg of guar gum, and sufficiently mix with a blender. Crosslinked. Add an equal volume of ethanol to this gel,
The gel was crushed with a blender and dehydrated. The dehydrated guar gum cross-linked product is washed, filtered, dried, and dried with 1-butanol at 130 ° C., 3
After heating for an hour, the water absorption performance was measured. The results are shown in Table 1.

Comparative Example 2 Zircosol AC-7 was used instead of TEAT used in Comparative Example 1.
A water-absorbing material was produced in the same manner as in Comparative Example 1 except that (manufactured by Nutex) was used (converted as zirconium ion content), and the water-absorbing performance was measured. The results are shown in Table 1.

Comparative Example 3 A 2% by mass aqueous solution of guar gum (manufactured by Sanei Chemical Trading Co., Ltd.) was swollen to prepare a sol solution. After swelling for 30 minutes, the sol liquid 200m
To the l, add a TEAT solution as a titanium ion content to 15 mmol per 1 kg of guar gum, and add an aqueous solution of sodium tetraborate decahydrate to a boron ion content to 500 mmol per 1 kg of guar gum, and sufficiently mix with a blender. Crosslinked. Add an equal volume of ethanol to this gel,
The gel was broken with a blender. Here, a TEAT solution was added as a titanium ion content of 85 mmol per 1 kg of guar gum, and reacted at room temperature for 20 minutes. The crosslinked guar gum after the reaction was washed, filtered and dried. 2 g of this crosslinked guar gum is
Butanol (40 ml) was added and reacted at 130 ° C. for 3 hours. The solid after the reaction was washed with ethanol and dried to obtain a water absorbing material of the present invention, and the water absorbing performance was measured. The results are shown in Table 1.

Comparative Example 4 Zircosol AC-7 was used instead of TEAT used in Comparative Example 3.
A water-absorbing material was prepared in the same manner as in Comparative Example 3 except that (manufactured by Nutex) was used (converted as zirconium ion content), and the water-absorbing performance was measured. The results are shown in Table 1.

As is evident from Table 1, the water-absorbing materials obtained in Examples 1 to 4 were excellent in urine resistance because they absorbed water more than 20 times with respect to a divalent or more cationic aqueous solution and artificial urine. On the other hand, it is clear that the water-absorbing materials obtained without performing the crosslinking with the epoxy compound (Comparative Examples 1 to 4) are inferior in texture after absorbing artificial urine.

[0054]

The absorbent of the present invention has a high water-absorbing ability of a cationic aqueous solution having a valency of 2 or less, has good gel stability when absorbing artificial urine, does not cause slippage, and has a hygienic material.
It is suitable as a water-absorbing material for various uses.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Satoko Wada 23 Uji Kozakura, Uji-city, Kyoto, Japan Inside Unitika Central Research Laboratory (72) Inventor Takemasa Yoshino 23 Uji Kozakura, Uji-city, Kyoto, Japan Unitika Central Research In-house F term (reference) 4G066 AC01B AC22D AE06B BA50 CA43 DA11 EA05 FA07 4J002 AB051 CD012 DA066 DA096 DA116 DD076 EC076 FD010 FD142 FD146 FD150 GD150 GD03

Claims (3)

[Claims] 1. A water-absorbing material, wherein galactomannan comprises a gel crosslinked with a polyvalent metal ion and an epoxy compound. 2. The water-absorbing material according to claim 1, wherein both the water absorption of the 0.9% by mass aqueous sodium chloride solution and the water absorption of the artificial urine are at least 20 times their own weight. 3. The method according to claim 1, wherein after the galactomannan is dissolved and swollen, a polyvalent metal ion is added to form a crosslinked body, and then the epoxy compound is mixed with the crosslinked body and heat-treated. The method for producing a water-absorbing material according to the above.