JP2001226404A - Fibrous water-absorbing material and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fibrous water-absorbing material that is biodegradable, exerts high gel strength after water absorption and high aqueous sodium chloride solution and provide a method for producing the same. SOLUTION: The objective fibrous water-absorbing material comprises galactomannan or its derivative and a polyvalent metallic ion and has the absorption of deionized water and 5 wt.%-concentration sodium chloride aqueous solution of >=20-fold self weight of the fiber material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-absorbing polymer composition suitably used for sanitary materials such as disposable diapers (disposable diapers), sanitary napkins and incontinence pads. Specifically, the present invention relates to polysaccharides having high biodegradability and 3
TECHNICAL FIELD The present invention relates to a water-absorbing agent comprising a polyvalent metal ion having a valency or higher and a method for producing the same. More specifically, the present invention relates to a water-absorbing agent having excellent sodium chloride aqueous solution-absorbing ability and easily decomposing at the time of disposal, and a method for producing the same.

[0002]

2. Description of the Related Art [Technical background of water-absorbent resin] A water-absorbent resin is a resin that can absorb water of several tens to several thousand times its own weight, and is used for sanitary products, disposable diapers, breast milk pads, disposable rags and the like. Supplies, dressings for wound protection, medical supplies such as medical underpads, cataplasms, pet sheets, portable toilets, gel fragrances, gel deodorants, household goods such as disposable warmers, shampoos, gels for setting , Moisturizing toiletries, water retention materials for agriculture and horticulture, cut flower life-promoting agents, floral foam (cut flower fixing material), nursery for nursery, hydroponic cultivation, vegetation sheet, seed tape, fluid sowing, dew condensation prevention Agricultural and horticultural products such as agricultural sheets, freshness-retaining materials for food trays, food packaging materials such as drip-absorbent sheets, cooling materials, transport materials such as water-absorbent sheets for transporting fresh vegetables, and dew condensation prevention Built material, sealing material for civil engineering and construction, lost circulation prevention agent of shield tunneling, concrete admixtures,
Materials for civil engineering and construction such as gaskets and packing, sealing materials for electronic devices such as optical fibers, waterproof materials for communication cables, materials for electric devices such as ink jet recording paper, coagulants for sludge, dehydration of gasoline and oils, and water removal. It is used in a wide range of fields such as water treatment agents such as agents, printing pastes, water-swellable toys, and artificial snow. In addition, utilizing the sustained release of the drug,
It is also expected to be used for sustained-release fertilizers, sustained-release pesticides, sustained-release drugs, and the like. In addition, using its hydrophilicity, humidity control materials,
It is also expected to be used for antistatic agents and the like by utilizing charge retention.

[Prior art relating to water-absorbing resin] As a water-absorbing resin used in such applications, for example, a partially neutralized cross-linked polyacrylic acid (JP-A-55-84304)
No. 4,625,001), a partially hydrolyzed starch-acrylonitrile copolymer (JP-A-46-4399).
No. 5), starch-acrylic acid graft copolymer (JP-A-5
1-125468), a hydrolyzate of a vinyl acetate-acrylate copolymer (JP-A-52-14689).
No.), copolymerized crosslinked product of 2-acrylamido-2-methylpropanesulfonic acid and acrylic acid (European patent 00681)
No. 89), a crosslinked product of a cationic monomer (US Pat.
No. 06717), a crosslinked isobutylene-maleic anhydride copolymer (US Pat. No. 4,389,513) and the like are known.

However, when such a particulate water-absorbing resin is used for sanitary goods, unless the resin is fixed to an adhesive sheet or the like, the resin is unevenly distributed in the sanitary goods and cannot exhibit high water absorption. There is a disadvantage that. In addition, even if the resin is fixed to the adhesive sheet, fine resin particles leak out and adhere to the portion directly in contact with the skin, which poses a problem on hygiene and convenience. For this reason, a water-absorbing sheet formed by processing a fibrous water-absorbing material (Japanese Unexamined Patent Publication No.
No. 18910, JP-A-56-118909, JP-A-5-118909
No. 6-118938 and JP-A-2-229260) have been developed.

However, since these water-absorbing resins and fibrous water-absorbing material compositions do not have decomposability, disposal after use is a problem. At present, these water-absorbent resins and fibers are incinerated at the time of disposal and landfilled.However, in the incinerator method, in addition to damage to the furnace material due to the heat generated during incineration, It is pointed out that it causes global warming and acid rain. Furthermore, when incinerating used paper diapers with a high water content, the combustion temperature inside the furnace decreases when charged into an incinerator, resulting in a combustion atmosphere in which furnace materials are likely to deteriorate and dioxins are generated. The burden on the equipment increases, and an exhaust gas treatment equipment with higher performance is required. In the landfill method, the plastic has a problem that the volume is bulky, the ground does not stabilize because it does not rot, and a major problem is that there is no longer a place suitable for landfill.

That is, since these resins and fibers are poorly degradable and exist semipermanently in water and soil,
This is a very serious problem when considering environmental conservation in waste disposal.

[Technical background of water-absorbing resin having biodegradability] On the other hand, in recent years, biodegradable polymers have attracted attention as “earth-friendly materials”, and it has been proposed to use this as a water-absorbing resin. ing. Examples of the biodegradable water-absorbing resin used for such applications include, for example, a polyethylene oxide crosslinked product (JP-A-6-15779).
No. 5, etc.), cross-linked polyvinyl alcohol, cross-linked carboxymethyl cellulose (US Pat. No. 4,650,716),
Alginic acid crosslinked products, starch crosslinked products, polyamino acid crosslinked products, and the like are known.

[0008] Currently, water-absorbent resins on the market are mainly polyacrylic acid-based resins that do not have biodegradability, and the water-absorbing agent has a very high deionized water absorption capacity of several hundred to 1,000 times. I have. However, the water-absorbing capacity of these water-absorbing agents, such as sodium chloride aqueous solution, such as physiological saline (0.9% by weight sodium chloride solution), is only about 50 to 75 g / g when quoted from numerical values in catalogs and the like. Most have only about 1/5 to 1/10. Furthermore, it has only about 20 to 25 g / g water absorption capacity for an aqueous solution having a high sodium chloride concentration, for example, seawater.

As a water absorbing agent comprising galactomannan or a derivative thereof and a polyvalent metal ion, a water absorbing agent comprising galactomannan and titanium or zirconium (US Pat. No. 5,553,235)
No. 0) and polysaccharides containing cis-1,2-diol and sodium borate (US Pat. No. 4,334,461). However, U.S. Pat.No. 5,532,350 discloses, as an example, that the carboxymethylated galactomannan and titanium or zirconium or both ions have the ability to absorb about 30 to 50 times its own weight of physiological saline by uniform internal crosslinking. However, the gels prepared according to these methods were not spinnable due to their high gel strength.

In US Pat. No. 4,334,461, a water-absorbing agent comprising galactomannan and sodium borate is prepared, and the ability to absorb physiological saline is measured. The present inventors also prepared a water-absorbing resin in which galactomannan was uniformly internally cross-linked with boron based on the examples, and measured the water-absorbing ability. The water-absorbing ability was 50 to 70 times that of physiological saline. However,
The gel obtained by this method was not one that could be spun because of high gel strength.

[0011]

Conventionally, galactomannan or a derivative thereof is dissolved and swelled with water as described in the above-mentioned patents and the like, and then polyvalent metal ions are added to cause internal cross-linking. Even if a good gel was prepared, the fiber could not be spun. In order to have an appropriate water absorption and gel strength of a water-absorbing agent that can be put to practical use, it is necessary to previously form a crosslinked gel composed of galactomannan or a derivative thereof having high gel strength and a polyvalent metal ion. It is practically impossible to spin the gel body from an existing spinning device because of its high viscoelasticity. In addition, a crosslinked gel having a low gel strength has too low mechanical strength during spinning and cannot be spun, or even if spun, the gel collapses due to low strength after water absorption. As a result, there was no fibrous water-absorbing material composed of galactomannan or a derivative thereof and trivalent or higher polyvalent metal ions.

As a biodegradable fibrous water-absorbing material, there is a patent for a method of producing a water-absorbing calcium alginate fiber by spinning a sodium alginate solution in a calcium bath, dehydrating with a hydrophilic organic solvent, and then drying. It is disclosed in JP-A-5-209318. The patent has a dry strength of 4.5 g / denier and a
Although water-absorbing biodegradable fibers having a physiological saline absorption of 0 g / g have been obtained, sodium alginate was expensive and could not be practically used in terms of cost.

An object of the present invention is to provide a fibrous water-absorbing material which has the above-mentioned conventional problems, has biodegradability, has high gel strength after water absorption, and has excellent sodium chloride aqueous solution-absorbing ability. It is in.

[0014]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a sol solution in which galactomannan or a derivative thereof is dissolved and swollen in water, or a gel having a low gel strength in which a polyvalent metal ion is internally cross-linked is used. Spinning from a nozzle of a spinning device, and cross-linking from the surface in a liquid containing trivalent or higher polyvalent metal ions, and then drying. The inventors have found that they have a high water absorption capacity of at least 20 times their own weight, which is almost the same as deionized water, and have completed the present invention.

That is, in the present invention, the fibrous water-absorbing material comprising galactomannan or a derivative thereof and a trivalent or higher polyvalent metal can absorb deionized water or a 5% by weight aqueous solution of sodium chloride at least 20 times its own weight. The present invention was found to be possible and spinning using an existing spinning device, and that the fibrous water-absorbing material had a stable water-absorbing ability that was hardly affected by the sodium chloride concentration of the liquid to be absorbed. . Incidentally, the aqueous sodium chloride solution in the present invention is not only an aqueous solution in which only sodium chloride is dissolved,
An aqueous solution in which another electrolyte (such as potassium chloride or magnesium sulfate) is dissolved together with sodium chloride is also indicated.

That is, the first aspect of the present invention comprises galactomannan or a derivative thereof and a polyvalent metal ion, and the water absorption of deionized water and the water absorption of an aqueous sodium chloride solution of 5% by weight or less are each 20 times as large as their own weight. The gist is a fibrous water-absorbing material characterized by the above. A second aspect of the present invention is to dissolve galactomannan or its derivative in water, spin it after swelling, and spin the galactomannan or its derivative solution in a solution containing polyvalent metal ions to form a fibrous hydrogel. The gist is a method for producing a fibrous water-absorbing material, wherein the fibrous water-absorbing material is obtained by drying the obtained fibrous hydrogel. After dissolving and swelling mannan or its derivative in water, it is crosslinked with polyvalent metal ions to form an internally crosslinked hydrogel, which is then spun from a nozzle, and then spun from the nozzle in a solution containing polyvalent metal ions. The fibrous hydrogel is formed by cross-linking the vicinity of the surface again to form a fibrous hydrogel, and drying the obtained fibrous hydrogel. The method for producing a fibrous water absorbing material and it is an gist.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a fibrous water-absorbing material of the present invention comprises: (a-1) supplying galactomannan or a derivative thereof to water to dissolve and swell; After supplying and dissolving and swelling mannan or a derivative thereof, one or more polyvalent metal ions are added to form an internal crosslink to form a gel having low gel strength and fluidity; (b) the galactomannan Or discharging the derivative solution or gel thereof in a fibrous form; and (c) discharging the discharged galactomannan or derivative solution thereof or the internally crosslinked gel.
It comprises the steps of cross-linking from the surface in a solution of one or more trivalent or higher polyvalent metal ions to form a fibrous gel, and (d) drying the fibrous gel.

The galactomannan or a derivative thereof used in the step (a-1) can be crosslinked with a polyvalent metal, and the crosslinked dried product has an ability to absorb an aqueous sodium chloride solution having a weight of 20 times or more its own weight. If there is, it is not particularly limited. For example, one or more galactomannans selected from the group of galactomannan (locust bean gum, guar gum), carboxymethyl galactomannan, carboxymethyl hydroxypropyl galactomannan, and derivatives thereof, and galactomannans are preferred. Mannan.

When the fibrous water-absorbing material of the present invention is prepared, the concentration of galactomannan or a derivative thereof dissolved in water may be such that galactomannan or a derivative thereof can be uniformly dissolved and swelled in water, and can be mixed with polyvalent metal ions. The concentration is not particularly limited as long as the gel can be formed at the time of crosslinking,
Preferably it is 0.1% to 20% by weight, more preferably 0.5% to 5% by weight or more. The dissolution temperature at this time is not particularly limited as long as galactomannan or a derivative thereof dissolves and swells, but is preferably 15 ° C to 90 ° C, more preferably 40 ° C to 70 ° C.
It is. The time involved in the dissolution of galactomannan or a derivative thereof varies depending on the concentration and temperature of the dissolution of galactomannan or a derivative thereof, but at least 30 minutes or more is required.

If the galactomannan or its derivative and the polyvalent metal ion are in a range that does not reduce the gel cross-linking and the water absorbing ability after drying, salt, colloidal silica, white salt, and the like are used for the purpose of improving the water absorption rate and the gel strength. Inorganic compounds such as carbon, ultrafine silica, and titanium oxide powder, and organic compounds such as chelating agents may be added.
Further, a plasticizer, an oxidizing agent, an antioxidant, a reducing agent, an ultraviolet absorber, an antibacterial agent, a bactericide, a fungicide, a fertilizer, a fragrance, a deodorant, a pigment and the like may be mixed. In some cases, a crosslinking retarder may be added.

As the plasticizer used in the present invention, various hydrophilic compounds can be used. The purpose is to impart flexibility to the fibrous water-absorbing material. The plasticizer used in the present invention is not particularly limited, but includes alcohols, carboxylic acids, sulfonic acids, glycols, water-soluble synthetic polymers, amino alcohols, monosaccharides, disaccharides, trisaccharides, 20
Types of essential amino acids, amino acids and amino acid derivatives, nucleic acids and their derivatives, phospholipids, vitamins and coenzymes. Of these, compounds having abundant hydrophilic groups in the molecule are preferable because they can be uniformly mixed. That is,
Glycerin, sorbitol, pentaerythritol, iduronic acid, galactic acid, α-galacturonic acid, glucaric acid, β-glucuronic acid, gluconic acid, guluronic acid, 2
-Deoxygluconic acid, mannuronic acid-6,3-lactone, α-galactosamine hydrochloride, α-mannosamine hydrochloride, muramic acid, alginic acid, chondroitin-4-sulfate, chondroitin-6-sulfate, hyaluronic acid, pekunanoic acid , Chitosan, chitosan-succinic acid modified product, cationized starch, carboxymethylcellulose, hydroxyethylcellulose, and cationized cellulose are preferable, and sorbitol, pentaerythritol, gluconic acid, α-galactosamine hydrochloride, chondroitin-4-
Sulfate, chondroitin-6-sulfate, alginic acid, hyaluronic acid, chitosan, modified chitosan-succinic acid, cationized starch, carboxymethyl cellulose, and cationized cellulose are particularly preferred. If necessary, the plasticizer used in the present invention may be used as a mixture with two or more other plasticizers. The use amount of these plasticizers is not particularly limited, but is preferably 0.1 to 70% by weight, more preferably 0.1 to 30% by weight, based on the water absorbing agent.

The galactomannan or a derivative thereof used in the step (a-2) of the present invention is prepared in the step (a-1).
Same as above, except that a galactomannan or its derivative galactomannan or its derivative solution is prepared in the step (a-1), and then at least one or more polyvalent metal ions are added to the galactomannan or its derivative solution as a crosslinking agent. ,
It is necessary to form a hydrogel having low gel strength and sufficient fluidity by mixing and internal crosslinking. Such polyvalent metal ions include calcium, magnesium, boron, titanium, zirconium, cerium, lanthanum, yttrium, iron, preferably calcium, magnesium, boron, titanium, zirconium, cerium, more preferably Boron and titanium.

Examples of the form of the polyvalent metal ion include chlorides, sulfates, carbonates, acetates, formic oxides, milk oxides, alkoxides, and the like. There is. For example, chloride and alkoxide are preferable for titanium, and sodium borate is preferable for boron. The cross-linking agent used in the present invention must contain at least one or more polyvalent metal ions, but other cross-linking agents such as glutaraldehyde and glyoxal may be used as long as the flowability and the water absorbing ability are not reduced. Aldehyde compounds such as ethylene diamine, amine compounds such as polyamide resin, 2,2-bishydroxymethylbutanol tri [3
-(1-aziridine)] aziridine compounds such as propionic acid, isocyanate compounds such as tolylene diisocyanate, hexamethylene diisocyanate and toluene diisocyanate, glycerol, propylene glycol,
Polyhydric alcohols such as ethylene glycol, epichlorohydrin, ethylene glycol diglycidyl ether,
It is also possible to use a mixture with an epoxy compound such as diethylene glycol diglycidyl ether. The polyvalent metal ion concentration used for cross-linking the solution of galactomannan or its derivative is not particularly limited because it is appropriately changed depending on the concentration of galactomannan or its derivative.
Preferably, the metal ion concentration is from 0.001 mM to 10 mM.
0 mM, and more preferably 0.01 mM to 50 mM.
It is. The temperature at which a crosslinked gel of soluble galactomannan or a derivative thereof and a polyvalent metal ion is formed is not particularly limited, but is also 5 to 90 ° C. to promote the reaction.
Is preferable, and 30 to 60 ° C is more preferable.

In the step (b) of the present invention, a highly viscous galactomannan or its derivative solution or a fluid hydrogel obtained by internally cross-linking a galactomannan or its derivative solution with a polyvalent metal ion is passed through a nozzle of an existing spinning apparatus. It is necessary to discharge. The type of galactomannan or its derivative and the concentration of galactomannan or its derivative,
The diameter and discharge speed of the nozzle may vary depending on the desired fiber thickness after drying, etc.
A preferred nozzle diameter is 0.01 to 1 mm, and 0.1
~ 0.5 mm is particularly preferred.

The crosslinking agent used in the step (c) of the present invention must contain at least one or more polyvalent metal ions. The kind of the polyvalent metal ion selected in the present invention is the same as in the step (a-2), and the form and concentration of the polyvalent metal ion are also the same. However, in this step, since it is necessary to prepare a fibrous gel having a strength that can be spun, the kind and concentration of the crosslinking agent used may be completely different from the step (a-2). The reaction time and reaction temperature required for cross-linking also vary depending on the type of galactomannan or a derivative thereof, the type and concentration of the cross-linking agent, the thickness of the discharged fibrous gel, the intended water-absorbing ability, and the like. The reaction time is preferably from 10 seconds to 2 hours, more preferably from 1 minute to 30 minutes. The temperature is not particularly limited, but may be 5 to 5 to promote the reaction.
90 ° C is preferred, and 30 to 60 ° C is more preferred.

After a highly fluid galactomannan or a derivative sol thereof or a gel having a low gel strength is discharged from a nozzle, a polyvalent metal ion is gradually crosslinked from the vicinity of the surface to the inside by the above-described method to obtain a high flow. A fibrous water-absorbing material having water absorption performance and gel strength can be easily produced.

In the step (d) of the present invention, any drying method is not limited as long as the method does not reduce the water absorption capacity after drying. Examples of the drying method include room temperature drying, heat drying, freeze drying, and reduced pressure. In addition to methods such as drying and vacuum drying, there is a method in which the surface crosslinked fibrous gel is washed with a hydrophilic solvent, and the moisture in the gel is replaced with a volatile anhydrous hydrophilic organic solvent, followed by hot air drying. Preferably, a hot air drying method by substitution with a hydrophilic organic solvent is used from the viewpoint of energy efficiency.

The thus obtained fibrous 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 hydrophilic short fiber, a plasticizer. , Adhesives, surfactants, fertilizers, oxidants, reducing agents,
Various functions may be imparted to the fibrous water-absorbing material by adding water, salts and the like. 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 amount of the inorganic powder used in the water-absorbing agent of the present invention depends on the combination of the water-absorbing agent and the inorganic powder, but is preferably in the range of 0.001 to 10 parts by weight, more preferably 0.1 to 10 parts by weight, per 100 parts by weight of the water-absorbing agent. It may be in the range of 01 to 5 parts by weight.

The fibrous water-absorbing material of the present invention can be processed as it is as a woven or non-woven fabric and used as a biodegradable fibrous water-absorbing material composition. Thus, an absorbent article can be obtained. 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, etc .; absorbent articles such as urine for pets; building materials and water retention materials for soil; Waterproof material, packing material,
Materials for civil engineering and construction such as gel sac; Food products such as drip absorbing material, freshness preserving material, and cold insulating material; Various industrial products such as oil-water separating material, anti-condensation material, solidifying material; Water retaining material 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.

In particular, the fibrous water-absorbing material of the present invention has a stable water-absorbing ability without being affected by the concentration of sodium chloride with respect to a high-concentration aqueous solution of sodium chloride. It is useful to use it for materials and dry batteries.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples. Example 1 4 g of guar gum (PF-20, manufactured by Sansei Co., Ltd.) was added to 200 ml of pure water heated to 50 ° C while stirring, and dissolved and swollen to prepare a sol solution. On the other hand, sodium borate and Ty
A boron-titanium bath adjusted to a boron concentration of 10.4 mM and a titanium concentration of 2.6 mM with zor TE (titanium IV triethanolaminate isopropoxide) solution (manufactured by DuPont; the titanium content of the stock solution is 15% by weight). Made with 200 ml of water. After swelling the guar gum sol for 1 hour,
The sol was supplied through a syringe with a nozzle diameter of 0.65 mm to boron-
The mixture was discharged at a rate of 1 m / min into a titanium bath and crosslinked in the bath at room temperature for 1 minute. After crosslinking, the fiber was taken up and dehydrated in ethanol for 5 minutes, and then dried at 40 ° C. for 1 hour to obtain a fibrous water-absorbing material. The water absorption of the fibrous water-absorbing material obtained as described above was measured.

The amount of water absorption was measured by the tea bag method using deionized water, a 0.9% by weight aqueous solution of sodium chloride (sodium chloride), a 5% by weight aqueous solution of sodium chloride (sodium chloride), artificial urine (1.94% by weight urea, 0.8% by weight sodium chloride,
840 ppm calcium chloride, 2050 ppm magnesium sulfate). That is, 0.1 g of a fibrous water-absorbing material was added to a 250-mesh nylon tea bag.
And 1 L of deionized water or 0.9 wt% saline, 5
A tea bag was immersed in a weight-% saline solution and artificial urine for 3 hours, the tea bag was pulled up, drained for 10 minutes, and the weight was measured. The amount of water absorbed by the fibrous water-absorbing material is determined based on the weight of the tea bag containing the fibrous water-absorbing material that has been swollen by absorbing water, with the weight of the tea bag containing no fibrous water-absorbing material soaked in water for 3 hours as a blank. The value obtained by dividing the value obtained by subtracting the weight of the fibrous water-absorbing material before and the weight of the blank by the weight of the fibrous water-absorbing material before swelling was defined as the water absorption (g / g).

As a result, the fibrous water-absorbing material obtained in this example had a water absorption of deionized water of 75 g / g, a water absorption of 0.9% by weight saline solution of 68 g / g, and a water absorption of 5% by weight saline solution. Is 60
g / g, and artificial urine water absorption was 62 g / g.

Example 2 Instead of Tyzor TE used as a cross-linking agent in Example 1, a Tyzor 131 solution (manufactured by DuPont; the titanium content of the stock solution was 6% by weight) was used, and the syringe nozzle diameter was reduced to 0.2 mm. A fibrous water-absorbing material was obtained in the same manner as in Example 1 except that the procedure was repeated.

The water-absorbing agent obtained in this example has a water absorption of 60 g / g of deionized water and a water absorption of 0.9% by weight of a saline solution of 54%.
g / g, 5% by weight saline water absorption was 53 g / g, and artificial urine water absorption was 50 g / g.

Example 3 Sodium tetraborate used as a crosslinking agent in Example 1
Zirconium chloride (manufactured by Nacalai Tesque) was used instead of TyzorTE, and the concentration of zirconium in the crosslinking agent bath was 5 m.
M, and after swelling, the same operation as in Example 1 was carried out except that the pH was adjusted to 8.5 by adding a 1N aqueous sodium hydroxide solution to the gel, to obtain a fibrous water-absorbing material. The fibrous water-absorbing material obtained in this example had a water absorption of 35 g / g of deionized water, a water absorption of 0.9% by weight of saline solution of 28 g / g, and a water absorption of 5% by weight of saline solution of 25 g / g, and was artificial. The amount of urine absorbed was 27 g / g.

Example 4 Instead of sodium tetraborate heptahydrate used as a cross-linking agent in Example 1, zirconium chloride, Tyzor 131
Instead of using cerium chloride heptahydrate (manufactured by Nacalai Tesque, Inc.), the boron concentration and zirconium concentration and the titanium concentration and the cerium concentration in the crosslinking agent bath were the same, and after swelling, a 1N aqueous sodium hydroxide solution was added to the gel. The procedure of Example 1 was repeated except that the pH was adjusted to 8.5 to obtain a fibrous water-absorbing material.

The fibrous water-absorbing material obtained in this example had a water absorption of 30 g / g of deionized water, a water absorption of 0.9% by weight saline solution of 32 g / g, and a water absorption of 5% by weight saline solution of 25 g / g. g, artificial urine water absorption was 22 g / g.

Example 5 CMHP guar gum (Jaguar 8600 manufactured by Rhodia) 2
g was added to 200 ml of pure water heated to 50 ° C. with stirring to dissolve and swell to prepare a sol solution. After swelling for 1 hour, a Tyzor 131 solution (manufactured by Du Pont; the titanium content of the stock solution is 6% by weight) is added to the sol so that the titanium concentration becomes 0.5 mM, and the mixture is further stirred at 50 ° C. for 30 minutes to reduce the gel strength. A gel was made. On the other hand, sodium borate and Tyzor TE (titanium IV triethanolaminate isopropoxide) solution (Du Pont:
The titanium content of the stock solution is 15% by weight) and the boron concentration is 5.2m
M, a boron-titanium bath adjusted to a titanium concentration of 1.3 mM was prepared with 200 ml of pure water. After swelling the guar gum sol for 1 hour, the sol solution was discharged from a syringe having a nozzle diameter of 0.65 mm into a boron-titanium bath at a rate of 1 m / min, and crosslinked in the bath at room temperature for 1 minute. After crosslinking, the fiber was taken up and dehydrated in ethanol for 5 minutes, and then dried at 40 ° C. for 1 hour to obtain a fibrous water-absorbing material.

The fibrous water-absorbing material obtained in this example had a water absorption of 72 g / g of deionized water, 40 g / g of 0.9% by weight saline solution and 39 g / g of 5% by weight saline solution. g, and artificial urine water absorption was 35 g / g.

COMPARATIVE EXAMPLE 1 Instead of sodium tetraborate heptahydrate used as a crosslinking agent in Example 1, calcium chloride (manufactured by Wako Pure Chemical Industries), T
The procedure was the same as in Example 1, except that magnesium chloride (manufactured by Nacalai Tesque) was used instead of yzor131, and the boron concentration and calcium concentration and titanium concentration and magnesium concentration in the crosslinking agent bath were the same. The gel formed therein had a low gel strength and could not be wound up, so that a fibrous water-absorbing material could not be obtained.

Comparative Example 2 In place of guar gum used as a polysaccharide in Example 1, C
The same operation as in Example 1 was carried out except that M starch (Nisseki Kagaku) was used. However, the gel formed in the crosslinking agent bath had low gel strength and could not be wound up. Could not be obtained.

As seen in Examples 1 to 6, the fibrous water-absorbing material comprising galactomannan and one or more trivalent or higher polyvalent metal ions according to the present invention contains 20 g / g or more of deionized water. 9% by weight saline solution, 5% by weight saline solution and artificial urine can be stably absorbed.

[0044]

According to the present invention, a fibrous water-absorbing material having a biodegradability of 20 times or more in deionized water and a 5% by weight aqueous sodium chloride solution can be easily produced using inexpensive raw materials. Therefore, it can be used as sanitary articles such as disposable diapers and sanitary articles, civil engineering materials, coagulants and the like.

Claims (3)

[Claims] 1. A method comprising galactomannan or a derivative thereof and a polyvalent metal ion, wherein the amount of deionized water absorbed and 5% by weight
A fibrous water-absorbing material, wherein each of the following sodium chloride aqueous solutions has a water absorption of at least 20 times its own weight. 2. A method of dissolving galactomannan or a derivative thereof in water, spinning after swelling from a nozzle, and crosslinking the galactomannan or derivative solution in a solution containing a polyvalent metal ion to form a fibrous hydrogel; A method for producing a fibrous water-absorbing material, comprising obtaining the fibrous water-absorbing material according to claim 1 by drying the obtained fibrous hydrogel. 3. After dissolving and swelling galactomannan or a derivative thereof in water, cross-linking with a polyvalent metal ion to form an internally crosslinked hydrogel, then spinning from a nozzle, and then spinning this solution containing a polyvalent metal ion 2. The fibrous water-absorbing material according to claim 1, wherein the fibrous hydrogel is formed by re-crosslinking the vicinity of the surface of the internally crosslinked hydrogel in the inside to form a fibrous hydrogel, and drying the obtained fibrous hydrogel. Manufacturing method of water absorbing material.