JP7059625B2 - Organic-inorganic composite hydrogel precursor composition, organic-inorganic composite hydrogel, organic-inorganic composite hydrogel junction, and method for producing the same. - Google Patents

Description

The present invention relates to a method for producing an organic-inorganic composite hydrogel precursor solution, an organic-inorganic composite hydrogel, and an organic-inorganic composite hydrogel junction.

A gel has properties intermediate between a liquid and a solid, and a substance such as an organic polymer forms a three-dimensional network in a solvent such as water and is in a stable state. In particular, a solvent whose solvent is water is called hydrogel, and its use as a functional material for medical treatment, food, sports, etc. has been developed. In particular, in order to have uniform transparency, tough mechanical properties, water absorption, biocompatibility, etc., composites with various materials and cross-linking structures have been devised.

For example, an invention relating to an organic-inorganic composite hydrogel in which water is contained in a three-dimensional network formed by a composite of a water-soluble organic polymer and a water-swellable clay mineral is described (for example, Patent Document). See 1.). According to the organic-inorganic composite hydrogel described in Patent Document 1, it is described that light transmission of 95% or more, water absorption of 10 times or more with respect to dry weight, and stretching of 10 times or more are possible.

Further, a filler for a concrete structure made of an organic-inorganic composite hydrogel has been proposed (see, for example, Patent Document 2), but when used as a filler for a concrete structure, high adhesion to concrete is required. In many cases, it has been required to improve the mechanical strength of the filler.

Further, as an application of use as a filler for a concrete structure, for example, use as a water blocking material against water leakage can be mentioned. In that case, it is often used at construction sites and repair sites of concrete structures, and storage stability as a filler is required so that it can be used as a concrete structure at any time. Also, especially for repair purposes, it is used in multiple places or divided into several times. For this reason, there is a possibility that a boundary surface between the fillers for the concrete structure may occur, and if the fillers are not sufficiently adhered to each other at the boundary surface between the fillers, water leakage will enter from the boundary surface and the water will stop. There was a problem that it could not be applied as a material.

Japanese Unexamined Patent Publication No. 2001-158634 Japanese Unexamined Patent Publication No. 2017-186182

An object to be solved by the present invention is to provide a composition capable of obtaining an organic-inorganic composite hydrogel having excellent storage stability, breaking strength and adhesive strength between gels.

According to the present inventors, the organic-inorganic composite hydrogel precursor liquid containing a water-soluble organic monomer, a water-swellable clay mineral, cellulose nanofibers, and water has excellent storage stability, excellent breaking strength, and excellent adhesion between gels. The present invention has been completed by finding that an organic-inorganic composite hydrogel can be obtained.

That is, the present invention is an organic-inorganic composite hydrogel precursor liquid and an organic-inorganic composite, which are characterized by containing a water-soluble organic monomer (A), a water-swellable clay mineral (B), a cellulose nanofiber (C), and water. It provides a hydrogel, an organic-inorganic composite hydrogel junction, and a method for producing the same.

The organic-inorganic composite hydrogel precursor composition of the present invention can be applied to various industrial applications such as civil engineering work sites because it can obtain an organic-inorganic composite hydrogel having excellent storage stability, breaking strength and adhesive strength between hydrogels. can do.

The organic-inorganic composite hydrogel precursor composition of the present invention contains a water-soluble organic monomer (A), a water-swellable clay mineral (B), a cellulose nanofiber (C), and water.

Examples of the water-soluble organic monomer (A) include a monomer having a (meth) acrylamide group, a monomer having a (meth) acryloyloxy group, an acrylic monomer having a hydroxyl group, and the like.

Examples of the monomer having a (meth) acrylamide group include acrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-methylacrylamide, N-ethylacrylamide, N-isopropylacrylamide, and N-cyclopropylacrylamide. , N, N-dimethylaminopropylacrylamide, N, N-diethylaminopropylacrylamide, acryloylmorpholine, methacrylamide, N, N-dimethylmethacrylate, N, N-diethylmethacrylate, N-methylmethacrylate, N-ethyl Examples thereof include methacrylamide, N-isopropylmethacrylate, N-cyclopropylmethacrylate, N, N-dimethylaminopropylmethacrylate, N, N-diethylaminopropylmethacrylate and the like.

Examples of the monomer having a (meth) acryloyloxy group include methoxyethyl acrylate, ethoxyethyl acrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, methoxymethyl acrylate, and ethoxymethyl acrylate.

Examples of the acrylic monomer having a hydroxyl group include hydroxyethyl acrylate and hydroxyethyl methacrylate.

Among these, from the viewpoint of solubility, breaking strength of the obtained organic-inorganic hydrogel, and adhesion between hydrogels, it is preferable to use a monomer having a (meth) acrylamide group, and acrylamide, N, N-dimethylacrylamide, N, It is more preferable to use N-diethylacrylamide, N-isopropylacrylamide, and acryloylmorpholine, and it is further preferable to use N, N-dimethylacrylamide and acryloylmorpholine. From the viewpoint that polymerization is easy to proceed, N, N-dimethyl Acrylamide is particularly preferred.

The above-mentioned water-soluble organic monomer (A) may be used alone or in combination of two or more.

The water-swellable clay mineral (B) forms a three-dimensional network structure together with the polymer of the water-soluble organic monomer, and becomes a constituent element of the organic-inorganic hydrogel.

The water-swellable clay mineral is not particularly limited, and examples thereof include water-swellable smectite and water-swellable mica.

Examples of the water-swellable smectite include water-swellable hectorite, water-swellable montmorillonite, and water-swellable saponite.

Examples of the water-swellable mica include water-swellable synthetic mica.

Among these, from the viewpoint of the stability of the dispersion liquid, it is preferable to use water-swellable hectorite and water-swellable montmorillonite, and it is more preferable to use water-swellable hectorite.

As the water-swellable clay mineral (B), naturally derived ones, synthetic ones, and surface-modified ones can also be used. Examples of the surface-modified water-swellable clay mineral include phosphonic acid-modified synthetic hectorite and fluorine-modified synthetic hectorite. Phosphonate can be obtained from the viewpoint of strength and adhesiveness of the obtained organic-inorganic composite hydrogel. It is preferable to use modified synthetic hectorite.

The above-mentioned water-swellable clay mineral (B) may be used alone or in combination of two or more.

By containing the cellulose nanofibers (C), the organic-inorganic composite hydrogel precursor composition of the present invention has excellent storage stability, excellent breaking strength of the obtained hydrogels, and excellent adhesion between hydrogels. ..

The cellulose nanofiber (C) is a defibrated and / or finely divided product of various types of cellulose.

As the cellulose, pulp, cotton, paper, regenerated cellulose fibers such as rayon, cupra, polynosic and acetate, bacterially produced cellulose, animal-derived cellulose such as squirrel and the like can be used. Further, these celluloses may have a surface chemically modified, if necessary.

The defibration and / or miniaturization of the cellulose nanofiber (C) can be performed, for example, by adding cellulose to a defibration resin such as water or a polyester resin and mechanically applying a shearing force.

As a means for applying the shearing force, a bead mill, an ultrasonic homogenizer, a single-screw extruder, an extruder such as a twin-screw extruder, a Banbury mixer, a grinder, a pressure kneader, a known kneader such as a double roll, or the like can be used. can. The above means may be used alone or in combination of two or more.

Further, the cellulose nanofiber (C) is a modified cellulose obtained by defibrating and / or refining cellulose to produce cellulose nanofibers, and then further adding a modifying compound and reacting with the cellulose nanofibers. It may be nanofiber.

As the compound to be modified, a functional group such as an alkyl group, an acyl group, an acylamino group, a cyano group, an alkoxy group, an aryl group, an amino group, an aryloxy group, a silyl group and a carboxyl group is chemically bonded to a cellulose nanofiber. Examples thereof include compounds to be modified.

Further, the cellulose nanofibers may be modified in such a manner that the modifying compound physically adsorbs to the cellulose nanofibers without chemically binding. Examples of the compound that is physically adsorbed include a surfactant and the like, and any of anionic, cationic and nonionic compounds may be used.

The fiber diameter and the aspect ratio of the cellulose nanofiber (C) are not particularly limited, but the fiber diameter is preferably 1000 nm or less, more preferably 100 nm or less.

Commercially available products of the cellulose nanofiber (C) include "Cerish" manufactured by Daicel FineChem Co., Ltd., "Leocrysta" manufactured by Dai-Dai Kogyo Seiyaku Co., Ltd., "BiNFi-s" manufactured by Sugino Machine Limited, and Nippon Paper Industries Co., Ltd. The company's "cellenpia" and the like can be mentioned.

The content of the water-soluble organic monomer (A) in the organic-inorganic composite hydrogel precursor composition of the present invention is preferably 1 to 50% by mass, more preferably 5 to 30% by mass. When the content of the water-soluble organic monomer (A) is 1% by mass or more, a hydrogel having excellent mechanical characteristics can be obtained, which is preferable. On the other hand, when the content of the water-soluble organic monomer is 50% by mass or less, the composition can be easily prepared, which is preferable.

The content of the water-swellable clay mineral in the organic-inorganic composite hydrogel precursor composition of the present invention is preferably 1 to 20% by mass, more preferably 2 to 10% by mass. When the content of the water-swellable clay mineral is 1% by mass or more, it is preferable because a hydrogel having excellent mechanical properties can be synthesized. On the other hand, when the content of the water-swellable clay mineral is 20% by mass or less, the precursor composition can be easily prepared, which is preferable.

The content of the cellulose nanofibers (C) in the organic-inorganic composite hydrogel precursor composition of the present invention is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass. It is preferably 1 to 20% by mass, and more preferably 1 to 20% by mass. When the content of the cellulose nanofibers is 0.1% by mass or more, it is preferable because it is possible to synthesize a hydrogel having excellent storage stability, breaking strength of the obtained hydrogel and adhesive strength between the hydrogels. On the other hand, when the content of the cellulose nanofibers is 50% by mass or less, the precursor composition can be easily prepared, which is preferable.

The organic-inorganic composite hydrogel precursor composition of the present invention can be obtained, for example, by adding the cellulose nanofibers to a mixture of the water-soluble organic monomer (A), the water-swellable clay mineral (B) and water. ..

As a method for producing an organic-inorganic composite hydrogel of the present invention, since an organic-inorganic composite hydrogel having a three-dimensional network structure can be easily obtained, the organic-inorganic composite hydrogel precursor composition, the polymerization initiator (D), and the polymerization initiator (D) are used. A method of polymerizing the water-soluble organic monomer (A) in the dispersion liquid (X) containing the polymerization accelerator (E) is preferable. The obtained polymer of the water-soluble organic monomer forms a three-dimensional network structure together with the water-swellable clay mineral, and becomes a component of the organic-inorganic composite hydrogel.

The polymerization initiator (D) is not particularly limited, and examples thereof include water-soluble peroxides and water-soluble azo compounds.

Examples of the water-soluble peroxide include potassium peroxodisulfate, ammonium peroxodisulfate, sodium peroxodisulfate, t-butyl hydroperoxide and the like.

Examples of the water-soluble azo compound include 2,2'-azobis (2-methylpropionamidine) dihydrochloride, 4,4'-azobis (4-cyanovaleric acid) and the like.

Among these, from the viewpoint of interaction with the water-swellable clay mineral (B), it is preferable to use a water-soluble peroxide, and potassium peroxodisulfate, ammonium peroxodisulfate, and sodium peroxodisulfate may be used. It is more preferable to use sodium peroxodisulfate and ammonium peroxodisulfate.

The polymerization initiator (D) may be used alone or in combination of two or more.

The molar ratio of the polymerization initiator (D) to the water-soluble organic monomer (A) in the dispersion liquid (X) (polymerization initiator (D) / water-soluble organic monomer (A)) is preferably 0.01. The above is more preferably 0.02 to 0.1, and even more preferably 0.04 to 0.1.

The content of the polymerization initiator in the dispersion liquid (X) is preferably 0.1 to 10% by mass, more preferably 0.2 to 10% by mass. When the content of the polymerization initiator is 0.1% by mass or more, the organic monomer can be polymerized even in an air atmosphere, which is preferable. On the other hand, when the content of the polymerization initiator is 10% by mass or less, the dispersion liquid can be used without agglomeration before the polymerization, and the handleability is improved, which is preferable.

Examples of the polymerization accelerator (E) include tertiary amine compounds, thiosulfates, ascorbic acids and the like.

Examples of the tertiary amine compound include N, N, N', N'-tetramethylethylenediamine and 3-dimethylaminopropionitrile.

Examples of the thiosulfate include sodium thiosulfate and ammonium thiosulfate.

Examples of the ascorbic acid include L-ascorbic acid and sodium L-ascorbic acid.

Of these, from the viewpoint of affinity and interaction with water-swellable clay minerals, it is preferable to use a tertiary amine compound, and it is more preferable to use N, N, N', N'-tetramethylethylenediamine.

The polymerization accelerator (E) may be used alone or in combination of two or more.

When the polymerization accelerator is used, the content of the polymerization accelerator in the dispersion liquid (X) is preferably 0.01 to 1% by mass, more preferably 0.05 to 0.5% by mass. preferable. When the content of the polymerization accelerator is 0.01% by mass or more, the synthesis of the organic monomer of the obtained hydrogel can be efficiently promoted, which is preferable. On the other hand, when the content of the polymerization accelerator is 1% by mass or less, the dispersion liquid can be used without agglomeration before the polymerization, and the handleability is improved, which is preferable.

The dispersion liquid (X) may contain an organic solvent, an organic cross-linking agent, a preservative, a thickener and the like, if necessary.

Examples of the organic solvent include alcohol compounds such as methanol, ethanol, propanol, isopropyl alcohol and 1-butanol; ether compounds such as ethyl ether and ethylene glycol monoethyl ether; amide compounds such as dimethylformamide and N-methylpyrrolidone; acetone, Examples thereof include ketone compounds such as methyl ethyl ketone.

Among these, from the viewpoint of dispersibility of the water-swellable clay mineral, it is preferable to use an alcohol compound, more preferably methanol, ethanol, n-propyl alcohol and isopropyl alcohol, and further preferably use methanol and ethanol. preferable.

These organic solvents may be used alone or in combination of two or more.

As a method for preparing the dispersion liquid (X), for example, a method of collectively mixing an organic-inorganic composite hydrogel precursor composition, the polymerization initiator (D), the polymerization accelerator (E), and the like; an organic-inorganic composite hydrogel. A multi-liquid mixing method in which a precursor composition, a solution containing the polymerization initiator (D), and a solution containing the polymerization accelerator (E) are prepared as separate dispersions or solutions and mixed immediately before use. However, a multi-liquid mixing method is preferable from the viewpoints of dispersibility, storage stability, viscosity control, and the like.

Examples of the solution containing the polymerization initiator (D) include an aqueous solution obtained by mixing the polymerization initiator (D) and water.

Examples of the solution containing the polymerization accelerator (E) include an aqueous solution obtained by mixing the polymerization accelerator (E) and water.

The organic-inorganic composite hydrogel of the present invention can be obtained by polymerizing the water-soluble organic monomer (A) in the dispersion liquid (X), but the polymerization method is not particularly limited and is carried out by a known method. be able to. Specific examples thereof include radical polymerization by heating and irradiation with ultraviolet rays, radical polymerization using a redox reaction, and the like.

The polymerization temperature is preferably 10 to 80 ° C, more preferably 20 to 80 ° C. When the polymerization temperature is 10 ° C. or higher, the radical reaction can proceed in a chain reaction, which is preferable. On the other hand, when the polymerization temperature is 80 ° C. or lower, the water contained in the dispersion liquid can be polymerized without boiling, which is preferable.

The polymerization time varies depending on the type of the polymerization initiator (D) and the polymerization accelerator (E), but is carried out between several tens of seconds and 24 hours. In particular, in the case of radical polymerization using heating or redox, it is preferably 1 to 24 hours, more preferably 5 to 24 hours. When the polymerization time is 1 hour or more, the polymer of the water-swellable clay mineral (B) and the water-soluble organic monomer (A) can form a three-dimensional network, which is preferable. On the other hand, since the polymerization reaction is almost completed within 24 hours, the polymerization time is preferably 24 hours or less.

The organic-inorganic composite hydrogel junction of the present invention is a junction of organic-inorganic composite hydrogels, but since it can be applied to industrial applications such as civil engineering work and construction work, it is used in a tensile test according to JIS K 6251: 2010. The breaking strength is preferably 0.1 MPa or more.

As a method for producing an organic-inorganic composite hydrogel bonded product of the present invention, since the bonded product can be easily obtained, the organic-inorganic composite hydrogel, the organic-inorganic composite hydrogel precursor composition, the polymerization initiator (D) and the polymerization are added to the organic-inorganic composite hydrogel. A method of shaping a solution containing the accelerator (E) is preferred.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The viscosity is a value measured by measuring a sample at 25 ° C. using a B-type viscometer (“VISCOMETER TV-20” manufactured by Toki Sangyo Co., Ltd.).

(Example 1: Preparation of organic-inorganic composite hydrogel precursor composition (1))
In a flat-bottomed glass container, 90 mL of pure water, 4.8 g of synthetic hectorite (“Laponite RDS” manufactured by Big Chemie Japan Co., Ltd.), and 20 g of dimethylacrylamide (hereinafter abbreviated as “DMAA”) are placed and uniformly transparent by stirring. An aqueous solution was prepared. Next, 10 g of cellulose nanofibers (“Cerish KY100G” manufactured by Daicel FineChem Co., Ltd., hereinafter abbreviated as “CNF (1)”) is added to this aqueous solution with stirring little by little to form an organic-inorganic composite hydrogel precursor composition (1). 1) was prepared. The appearance of this organic-inorganic composite hydrogel precursor composition (1) was a uniform pale white color, and no particular agglomerates were observed. The initial viscosity was 35 mPa · s.

[Evaluation of storage stability]
The organic-inorganic composite hydrogel precursor composition (1) obtained above is sealed and stored in a 50 ° C. incubator, taken out after 1 week, and the viscosity at 25 ° C. (viscosity after storage) is measured again and described below. Storage stability was evaluated according to the criteria.
◯: Viscosity after storage (mPa · s) is less than 200% of initial viscosity (mPa · s) ×: Viscosity after storage (mPa · s) is 200% or more of initial viscosity (mPa · s)

[Manufacturing of organic-inorganic composite hydrogel]
A uniform transparent NPS aqueous solution was prepared by putting 10 mL of pure water and 0.5 g of sodium persulfate (hereinafter abbreviated as "NPS") in a flat-bottomed glass container and stirring the mixture. In still another flat-bottomed glass container, 10 mL of pure water and 80 μL of tetramethylethylenediamine (hereinafter abbreviated as “TEMED”) were put and stirred to prepare a uniform TEMED aqueous solution.
In a 200 mL glass beaker, 120 g of the organic-inorganic composite hydrogel precursor composition (1) obtained above is placed, and the NPS aqueous solution and the TEMED aqueous solution prepared above are added while stirring, and the mixture is stirred until uniformly mixed. Subsequently, an aqueous solution (X-1) was prepared. Immediately after preparing the aqueous solution (X-1), two glass plates having a thickness of 5 mm were put together via a spacer of 2 mm, and the mixture was poured into a gap of 2 mm and allowed to stand at room temperature for 24 hours to have a thickness of 2 mm. The organic-inorganic composite hydrogel (1) of the above was produced. When the state of the liquid poured after 24 hours was confirmed, a uniform and slightly pale white sheet of the organic-inorganic composite hydrogel (1) was obtained.

[Evaluation of breaking strength of organic-inorganic composite hydrogel]
The sheet of the organic-inorganic composite hydrogel (1) obtained above was subjected to a tensile test according to the test method of JIS K 6251: 2010 to evaluate the breaking strength. The sample for the tensile test was a dumbbell shape of JIS3. The conditions of the tensile test were a tensile tester (Autograph AG-10KNX, manufactured by Shimadzu Corporation), and the sample was stretched at 23 ° C. and a tensile speed of 500 mm / min until the sample broke.

[Manufacturing of organic-inorganic composite hydrogel junctions]
Put 10 mL of an aqueous solution (X-1) in a 20 mL glass test tube with an inner diameter of 13 mm, cover the glass test tube, and leave it at room temperature for 24 hours to prepare an organic-inorganic composite hydrogel (1-1). bottom. Then, a new aqueous solution (X-1) was prepared, and 10 mL was poured again into a glass test tube containing the organic-inorganic composite hydrogel (1-1). After that, the glass test tube was covered and allowed to stand at room temperature for 24 hours. After 24 hours, when the inside of the glass test tube was checked, a uniform and slightly pale white organic-inorganic composite hydrogel junction (1) in which the aqueous solution (X-1) poured into the glass test tube in two steps was integrated. )was gotten.

[Evaluation of Adhesiveness of Organic-Inorganic Composite Hydrogel Bonds]
The organic-inorganic composite hydrogel junction (1) obtained above was carefully taken out from the glass test tube, a tensile test was carried out by a test method according to JIS K 6251: 2010, and the organic-inorganic composite hydrogel junction was subjected to the following criteria. Adhesion was evaluated. If the joint surface was not adhered at all, the breaking strength was set to "not measurable". If the gel was brittle and broke immediately after the start of the test, the rupture strength was rated as "unevaluable".
The sample for the tensile test was a cylinder taken out from a glass test tube. The conditions of the tensile test were a tensile tester (Autograph AG-10KNX, manufactured by Shimadzu Corporation), and the sample was stretched at 23 ° C. and a tensile speed of 500 mm / min until the sample broke. The sample of the tensile tester was attached so that the distance between the scissors and the joint of the hydrogel was the same for both of the two scissors.
◯: Break at a joint surface ×: Break at a joint surface

(Example 2: Preparation of organic-inorganic composite hydrogel precursor composition (2))
90 mL of pure water, 4.8 g of synthetic hectorite (“Laponite RDS” manufactured by Big Chemie Japan Co., Ltd.), and 20 g of dimethylacrylamide (DMAA) were placed in a flat-bottomed glass container, and a uniform transparent aqueous solution was prepared by stirring. Next, 20 g of cellulose nanofibers (“Leocrysta” manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., hereinafter abbreviated as “CNF (2)”) is added to this aqueous solution with stirring little by little to form an organic-inorganic composite hydrogel precursor composition. (1) was prepared. The appearance of this organic-inorganic composite hydrogel precursor composition (2) was a uniform pale white color, and no particular agglomerates were observed. The initial viscosity was 22 mPa · s.

The aqueous solution (X-2) and the organic are the same as in Example 1 except that the organic-inorganic composite hydrogel precursor composition (1) of Example 1 is changed to the organic-inorganic composite hydrogel precursor composition (2). An inorganic composite hydrogel (2) and an organic-inorganic composite hydrogel junction (2) were produced and various physical characteristics were evaluated.

(Comparative Example 1: Preparation of Comparative Composition (R1))
90 mL of pure water, 20 g of DMAA, and 0.02 g of methylenebisacrylamide as a cross-linking agent were placed in a flat-bottomed glass container, and a uniform transparent aqueous solution was prepared by stirring.
Next, 10 g of CNF (1) was added to this aqueous solution little by little with stirring to prepare a comparative composition (R1). The appearance of this comparative composition (R1) was a uniform pale white color, and no agglomerates were particularly observed. The initial viscosity was 22 mPa · s.

An aqueous solution (RX-1) and a hydrogel (R-1) were obtained in the same manner as in Example 1 except that the organic-inorganic composite hydrogel precursor composition (1) of Example 1 was changed to the comparative composition (R1). ), A hydrogel junction (R-1) was produced, and various physical properties were evaluated.

(Comparative Example 2: Preparation of Comparative Composition (R2))
90 mL of pure water, 4.8 g of synthetic hectorite (“Laponite RDS” manufactured by Big Chemie Japan Co., Ltd.), and 20 g of DMAA were placed in a flat-bottomed glass container, and a uniform transparent comparative composition (R2) was prepared by stirring. .. The initial viscosity of this comparative composition (R2) was 3 mPa · s.

An aqueous solution (RX-2) and a hydrogel (R-2) were obtained in the same manner as in Example 1 except that the organic-inorganic composite hydrogel precursor composition (1) of Example 1 was changed to the comparative composition (R2). ), A hydrogel junction (R-2) was produced, and various physical properties were evaluated.

The evaluation results obtained above are shown in Table 1.

It was confirmed that the organic-inorganic composite hydrogel precursor composition of the present invention of Examples 1 and 2 was excellent in storage stability, the breaking strength of the obtained hydrogel, and the adhesiveness between hydrogels.

On the other hand, Comparative Example 1 is an example which does not contain the water-swellable clay mineral which is an essential component of the present invention, but it was confirmed that the storage stability was insufficient and the breaking strength of the obtained hydrogel was inferior.

On the other hand, Comparative Example 2 is an example which does not contain the cellulose nanofiber which is an essential component of the present invention, but it was confirmed that the storage stability was insufficient and the adhesiveness between the obtained hydrogels was inferior.

Claims (1)

On the surface of an organic-inorganic composite hydrogel which is a reaction product of an organic-inorganic composite hydrogel precursor composition containing a water-soluble organic monomer (A), a water-swellable clay mineral (B), a cellulose nanofiber (C), and water . Contains the water-soluble organic monomer (A), the water-swellable clay mineral (B), the cellulose nanofibers (C), and an organic-inorganic composite hydrogel precursor composition containing water , a polymerization initiator and a polymerization accelerator. A method for producing an organic-inorganic composite hydrogel conjugate obtained by shaping a solution to be formed.