Organic-inorganic composite hydrogel precursor liquid, hydrogel shaped article, and method for producing hydrogel shaped article

Abstract

To provide an organic-inorganic composite hydrogel precursor liquid that can give a shaped hydrogel having excellent compression stress and rupture limit.SOLUTION: An organic-inorganic composite hydrogel precursor liquid contains a monomer having a hydroxy group, a borate compound, and water.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an organic-inorganic composite hydrogel precursor liquid, an organic-inorganic composite hydrogel, a hydrogel shaped article, and a method for producing a hydrogel shaped article.

Background Art

[0002] In recent years, new surgical procedures and medical devices such as laparoscopic surgery and endovascular surgery have emerged, and minimally invasive surgery that can be expected to improve the postoperative recovery and quality of life (QOL) of patients has advanced rapidly. Along with such rapid progress in medical technology, there are quite a few doctors who have to go to surgery without sufficient acquisition of technology, and the increasing tendency of medical accidents has become a major social problem. Therefore, a training system that enables sufficient acquisition of technology before surgery is required.

[0003] On the other hand, surgical training for cultivating specialists is carried out by using experimental animals, cadavers (human corpses for dissection), clinical trials on patients, etc. From a social and ethical point of view, it is required to reduce the frequency of using experimental animals and cadavers. In order to reduce the frequency of using experimental animals and cadavers, the demand for a training system that can achieve alternative medical technology and improve safety is increasing.

[0004] To solve the above problems, a three-dimensional shaped model of a diseased part or a specific part of the body (hereinafter sometimes referred to as an "organ model") is used. By using an organ model, not only visually but also by actually touching and seeing the three-dimensional shape, a lot of information that cannot be conveyed by a computer image can be conveyed. As a function required for such an organ model, it is important to bring the tactile sensation closer to the living body texture. For example, if one can touch the organ model by hand and be informed that there are differences in flexibility and stretchability depending on the part, and that there are differences in hardness between the affected part and the healthy part, the effects of medical education and informed consent can be enhanced. In addition, it is preferable that the surface and internal structure of the organ model can be reproduced. Furthermore, if functions such as being able to be incised with an energy device such as an electric scalpel and being able to be contrasted at a specific site by computed tomography (CT) are imparted, the types of training that can be realized can be significantly increased.

[0005] Therefore, various organ models having a tactile sensation close to that of a living body and imparted with desired functions have been proposed. For example, a hydrogel precursor liquid containing an inorganic mineral, a monomer, and a phosphonic acid compound, and a hydrogel formed body obtained using the hydrogel precursor liquid have been proposed (see, for example, Patent Document 1). Also, a borate group-containing organo-inorganic composite hydrogel in a three-dimensional network of an organo-inorganic composite hydrogel having an amino group formed by an amino group-containing water-soluble organic polymer (A), a water-swellable clay mineral (B), and water (C) has been proposed (see, for example, Patent Document 2). In addition, a silicone hydrogel material obtained by curing a reaction mixture containing a hydrophilic component-containing monomer or macromer, a siloxane-containing monomer or macromer, and a borate has been proposed (see, for example, Patent Document 3). Summary of the Invention Problems to be Solved by the Invention

[0006] An object of the present invention is to provide an organo-inorganic composite hydrogel precursor liquid capable of forming a hydrogel formed body having excellent compressive stress and breaking limit. Means for Solving the Problems

[0007] The organic-inorganic composite hydrogel precursor solution of the present invention as a means for solving the above problems contains a monomer having a hydroxy group, a borate compound, and water.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide an organic-inorganic composite hydrogel precursor solution capable of forming a hydrogel shaped article having excellent compressive stress and breaking limit.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0010] (Organic-Inorganic Composite Hydrogel Precursor Solution) The organic-inorganic composite hydrogel precursor solution of the present invention contains a monomer having a hydroxy group, a borate compound, and water, preferably contains an ionic compound and a monomer having an ethylene glycol skeleton, and further contains other components as necessary.

[0011] The prior art described in Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2016-176006) is a nanocomposite (NC) gel precursor solution containing inorganic minerals, and has a different composition from the organic-inorganic composite hydrogel precursor solution of the present invention. When an ionic compound is added to this NC gel precursor solution, there is a problem that the viscosity of the NC precursor solution increases and it cannot be shaped by the MJ (Material Jetting) method.

[0012] The prior art described in Patent Document 2 (Japanese Patent Application Laid-Open No. 2008-074925) is a nanocomposite (NC) gel precursor solution containing a clay mineral and having an amino group, and its composition is different from that of the organic-inorganic composite hydrogel precursor solution of the present invention. When the NC gel obtained using this NC gel precursor solution is immersed in an aqueous solution of an inorganic borate compound and the amino group and the inorganic borate compound are reacted to introduce a borate group into the NC gel, there is a problem that the shape of the NC gel changes due to swelling.

[0013] The prior art described in Patent Document 3 (Japanese Patent Application Laid-Open No. 2014-501799) is a silicone hydrogel material in which a borate crosslinks a hydrophilic component and a silicone component. Since it does not contain water, its composition is different from that of the organic-inorganic composite hydrogel precursor solution of the present invention, and since it is not a hydrogel containing water, there is a problem that it does not have a compression stress and a breaking limit suitable for an organ model.

[0014] In the present invention, when an organic-inorganic composite hydrogel precursor solution containing a monomer having a hydroxy group, a borate compound, and water is cured, a crosslinked structure is formed between the hydroxy group of the monomer having a hydroxy group and the boron of the borate compound, whereby a hydrogel molded article having excellent compression stress and breaking limit can be obtained. In addition, since a large amount of ionic compounds can be added to the organic-inorganic composite hydrogel precursor solution of the present invention, various functions can be imparted. For example, a function such as obtaining contrast in X-ray imaging and being able to be incised with an energy device such as an electric scalpel can be added to the hydrogel molded article. Furthermore, the organic-inorganic composite hydrogel precursor solution of the present invention has a low viscosity and can be cured by radical polymerization, so it is preferably used for high-definition molding and laminated molding typified by inkjet.

[0015] <Water> The water is not particularly limited and can be appropriately selected according to the purpose. For example, pure water, ultrapure water, etc. are exemplified, and more specifically, ion-exchanged water, ultrafiltration water, reverse osmosis water, distilled water, etc. are mentioned. The water content is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of obtaining a hydrogel molded article having a soft texture, 30% by mass or more, more preferably 40% by mass or more, and still more preferably 50.0% by mass or more, based on the total amount of the organic-inorganic composite hydrogel precursor liquid. Also, 90% by mass or less is preferable, and 80% by mass or less is more preferable.

[0016] <Monomer having a hydroxy group> The monomer having a hydroxy group is not particularly limited and can be appropriately selected according to the purpose. For example, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 4-hydroxybutyl acrylate (4-HBA), 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, N-(hydroxymethyl)acrylamide, hydroxyethyl acrylamide (HEAA), N-(hydroxymethyl)methacrylamide, 2-hydroxypropyl methacrylamide, 2-acryloyloxyethyl acid phosphate, or a reactive oligomer containing at least one of the above monomers can be mentioned. These may be used alone or in combination of two or more. Among these, from the viewpoint of the elongation rate of the obtained hydrogel molded article, 4-hydroxyethyl acrylamide (4-HBA) and hydroxyethyl acrylamide (HEAA) are preferable. The monomer having a hydroxy group may be used alone or in combination of two or more. The monomer having a hydroxyl group is preferably a compound having a photopolymerizable functional group. In the present invention, the term "polymerizable functional group" refers to a functional group that undergoes a polymerization reaction by irradiation with active energy rays or addition of heat, and the term "photopolymerizable functional group" refers to a functional group that undergoes a polymerization reaction by irradiation with active energy rays. Examples of the photopolymerizable functional group include, but are not limited to, groups having an ethylenically unsaturated bond such as a (meth)acryloyl group, a vinyl group, or an allyl group, and cyclic ether groups such as an epoxy group. Specific examples of the compound containing a group having an ethylenically unsaturated bond include a compound having a (meth)acrylamide group, a (meth)acrylate compound, a compound having a (meth)acryloyl group, a compound having a vinyl group, and a compound having an allyl group.

[0017] The content of the monomer having a hydroxyl group is preferably 5% by mass to 50% by mass, more preferably 10% by mass to 40% by mass, and even more preferably 15% by mass to 30% by mass, based on the total amount of the organic-inorganic composite hydrogel precursor liquid. When the content of the monomer having a hydroxyl group is 5% by mass to 50% by mass, the dispersion stability of the borate compound in the organic-inorganic composite hydrogel precursor liquid is improved.

[0018] <Borate compounds> The borate compound is not particularly limited and can be appropriately selected depending on the purpose. For example, sodium metaborate (NaBO 2 ), barium metaborate (Ba(BO 2 ) 2 ), Sodium Tetraborate (Na 2 B 4 O 7 ), disodium octaboronate (Na 2 B 8 O 13 ), sodium polyborate (SOUFA), etc. Naturally available substances include, for example, borax (Na 2 B 4 O 5 (OH) 4 8H 2 O / Na 2B 4 O 7 ·10H 2 O), small vine stone (Mg 3 (BO 3 ) 2 ) and the like can be mentioned. These may be used alone or in combination of two or more. Among these, sodium tetraborate, disodium octaborate decahydrate, and their hydrates are preferable in terms of obtaining the strength when the hydrogel molded article is compressed. Further, the borate compound is preferably a compound other than a borate ester. The content of the borate compound is preferably 0.1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 6% by mass or less, and still more preferably 2% by mass or more and 5% by mass or less, based on the total amount of the organic-inorganic composite hydrogel precursor liquid. If the content of the borate compound is less than 0.1% by mass, the crosslinking effect by the borate compound may not be obtained, and if it exceeds 20% by mass, the hydrogel molded article may become hard and it may be difficult to obtain elongation.

[0019] <Ionic compound> The ionic compound is added for the purpose of imparting a function to the hydrogel molded article. The ionic compound is not particularly limited as long as it is a substance that dissolves in water and is stable, and can be appropriately selected according to the required function. In the present disclosure, the "ionic compound" does not include the above-mentioned borate compound.

[0020] To impart a function of obtaining contrast when the hydrogel molded article is imaged by X-ray, it is preferable to add a contrast agent as the ionic compound. A contrast agent is a compound containing a substance that is difficult to transmit X-rays, and includes, for example, ions of elements with a large atomic weight such as iodine, barium, and cesium. Examples of the contrast agent include iodides such as sodium iodide (NaI), potassium iodide (KI), and calcium iodide (CaI 2 ), etc.; barium bromide (BaBr 2 ), barium chloride (BaCl 2 ), barium iodide (BaI 2Barium halide compounds such as ()); cesium halide compounds such as cesium bromide (CsBr), cesium chloride (CsCl), and cesium iodide (CsI) can be mentioned. These may be used alone or in combination of two or more. When a hydrogel molded article obtained by adding an ionic compound containing ions of such an element with a large atomic weight is subjected to X-ray imaging, contrast with other parts can be obtained.

[0021] On the other hand, in order to impart a function to the hydrogel molded article so that it can be cut with an energy device such as an electric scalpel, it is preferable to add an inorganic salt as the ionic compound. By adding an inorganic salt, the conductivity of the hydrogel molded article can be increased. The inorganic salt is not particularly limited as long as it can increase the conductivity of the hydrogel molded article by ionization, and includes acidic salts, neutral salts, and basic salts. Examples of the inorganic salt include ammonium chloride (NH 4 Cl), copper sulfate (CuSO 4 ), sodium hydrogen sulfate (NaHSO 4 ), sodium dihydrogen phosphate (NaH 2 PO 4 ), sodium chloride (NaCl), potassium chloride (KCl), calcium chloride (CaCl 2 ), lithium chloride (LiCl), sodium acetate (CH 3 COONa), sodium carbonate (Na 2 CO 3 ), sodium hydrogen carbonate (NaHCO 3 ), disodium hydrogen phosphate (Na 2 HPO 4 ) and the like. These may be used alone or in combination of two or more. As the ionic compound, both a contrast agent and an inorganic salt may be added, or either a contrast agent or an inorganic salt may be added.

[0022] The content of the ionic compound can be appropriately adjusted according to the function imparted to the hydrogel shaped article. By adjusting the content of the ionic compound, the contrast when X-ray imaging or the cuttability in an energy device can be adjusted. The content of the ionic compound is preferably 0.1% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, and still more preferably 5% by mass or more and 10% by mass or less, based on the total amount of the organic-inorganic composite hydrogel precursor liquid. If the content of the ionic compound is less than 0.1% by mass, almost no effect of the added ionic compound can be obtained. Further, if the content of the ionic compound exceeds 20% by mass, the quality is adversely affected, such as the hydrogel shaped article becoming brittle or the surface of the hydrogel shaped article being sticky (having strong tackiness).

[0023] <Monomer having an ethylene glycol skeleton> It is preferable to add a monomer having an ethylene glycol skeleton to the organic-inorganic composite hydrogel precursor liquid for the purpose of improving the strength of the hydrogel shaped article or adjusting the texture. Having an ether bond such as an ethylene glycol skeleton imparts water solubility and flexibility, so that a hydrogel shaped article that is easily soluble in water, flexible, and highly extensible can be obtained. Further, when the ethylene glycol in the molecular chain is replaced with propylene glycol or butylene glycol, the ratio of the ether skeleton contained in the molecule decreases, so that the solubility in water decreases. Examples of the monomer having an ethylene glycol skeleton include monofunctional (meth)acrylates such as ethoxy-diethylene glycol acrylate, methoxy-triethylene glycol acrylate, 2-ethylhexyl-diglycol acrylate, methoxy-polyethylene glycol acrylate, methoxy-tetraethylene glycol methacrylate, and methoxy-polyethylene glycol methacrylate; polyfunctional (meth)acrylates such as polyethylene glycol diacrylate, ethoxylated glycerin triacrylate, and polyethylene glycol dimethacrylate. These may be used alone or in combination of two or more. Among these, difunctional (meth)acrylate is preferable and polyethylene glycol diacrylate is more preferable because of its good solubility in water and the ability to obtain a highly extensible hydrogel shaped article. The content of the monomer having an ethylene glycol skeleton is preferably 0.01 or more and 0.5 or less, more preferably 0.1 or more and 0.3 or less, in terms of molar ratio with respect to the monomer having a hydroxy group being 1. If the molar ratio is less than 0.01, the stress of the hydrogel shaped article against compression may be insufficient. If it exceeds 0.5, the hydrogel shaped article tends to be brittle against elongation.

[0024] <Other components> As other components, monomers having no hydroxy group and no ethylene glycol skeleton, polymerization initiators, surfactants, colorants, moisturizers, and other additives can be appropriately contained as needed.

[0025] - Monomers having no hydroxy group and no ethylene glycol skeleton - Examples of monomers having no hydroxy group and ethylene glycol skeleton include acryloylmorpholine, dimethylacrylamide, diethylacrylamide, isopropylacrylamide, dimethylaminopropylacrylamide, dimethylaminopropylacrylamide methyl chloride quaternary salt, dimethylaminoethyl acrylate benzyl chloride quaternary salt acrylamide, N-substituted acrylamide derivatives of the acrylamide, N,N-disubstituted acrylamide derivatives, N-substituted methacrylamide derivatives, N,N-disubstituted methacrylamide derivatives, and other acrylamides. These may be used alone or in combination of two or more.

[0026] -Polymerization initiator- Examples of polymerization initiators include thermal polymerization initiators and photoinitiators. In the case of stereolithography, a photoinitiator can be used, and in the case of mold shaping, both a thermal polymerization initiator and a photoinitiator can be used. Examples of photoinitiators include any substance that generates radicals upon irradiation with light, particularly ultraviolet light having a wavelength of 220 nm to 550 nm. The polymerization initiator may be used alone or in combination of two or more. It is also preferable to select a photoinitiator that matches the ultraviolet wavelength of the ultraviolet irradiation device. Examples of the photoinitiator include acetophenone, 2,2 - diethoxyacetophenone, p - dimethylaminoacetophenone, benzophenone, 2 - chlorobenzophenone, p,p’ - dichlorobenzophenone, p,p - bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin - n - propyl ether, benzoin isobutyl ether, benzoin - n - butyl ether, benzyl methyl ketal, thioxanthone, 2 - chlorothioxanthone, 2 - hydroxy - 2 - methyl - 1 - phenyl - 1 - one, 1 - (4 - isopropylphenyl)2 - hydroxy - 2 - methylpropan - 1 - one, methyl benzoylformate, 1 - hydroxycyclohexyl phenyl ketone, azobisisobutyronitrile, benzoyl peroxide, bis(2,4,6 - trimethylbenzoyl)phenylphosphine oxide, di - tert - butyl peroxide, and the like.

[0027] There is no particular limitation on the thermal initiator, and it can be appropriately selected according to the purpose. Examples thereof include azo initiators, peroxide initiators, persulfate initiators, redox (oxidation - reduction) initiators, and the like. As the azo initiator, commercially available products can be used. Examples of the commercially available products include VA - 044, VA - 46B, V - 50, VA - 057, VA - 061, VA - 067, VA - 086, 2,2’ - azobis(4 - methoxy - 2,4 - dimethylvaleronitrile) (VAZO 33), 2,2’ - azobis(2 - amidinopropane) dihydrochloride (VAZO 50), 2,2’ - azobis(2,4 - dimethylvaleronitrile) (VAZO 52), 2,2’ - azobis(isobutyronitrile) (VAZO 64), 2,2’ - azobis - 2 - methylbutyronitrile (VAZO 67), 1,1 - azobis(1 - cyclohexanecarbonitrile) (VAZO 88) (all manufactured by DuPont Chemical, and “VAZO” is the trademark of the company), 2,2’ - azobis(2 - cyclopropylpropionitrile), 2,2’ - azobis(methyl isobutyrate) (V - 601) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the like. Examples of peroxide initiators include benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide, dicetyl peroxydicarbonate, di(4-t-butylcyclohexyl) peroxydicarbonate (Perkadox 16S) (manufactured by Akzo Nobel, "Perkadox" is a trademark of the company), di(2-ethylhexyl) peroxydicarbonate, t-butyl peroxypivalate (Lupersol 11) (manufactured by Elf Atochem, "Lupersol" is a trademark of the company), t-butyl peroxy-2-ethylhexanoate (Trigonox 21-C50) (manufactured by Akzo Nobel, "Trigonox" is a trademark of the company), dicumyl peroxide, and the like. Examples of persulfate initiators include potassium persulfate, sodium persulfate, ammonium persulfate, and the like. Examples of redox (oxidation-reduction) initiators include combinations of persulfate initiators with reducing agents such as sodium metabisulfite and sodium bisulfite, systems based on organic peroxides and tertiary amines, for example, systems based on benzoyl peroxide and dimethylaniline, systems based on organic hydroperoxides and transition metals, systems based on cumene hydroperoxide and cobalt naphthenate, and the like.

[0028] -Surfactant- Examples of surfactants include silicone-based surfactants, fluorine-based surfactants, amphoteric surfactants, nonionic surfactants, anionic surfactants, and the like. The surfactant may be used alone for the purpose of suppressing the bounce at the interface with the support part. However, in addition to suppressing the bounce, it is preferable to use two or more kinds in combination in order to improve other properties such as dischargeability or curability.

[0029] Examples of silicone-based surfactants include side-chain modified polydimethylsiloxane, both-end modified polydimethylsiloxane, one-end modified polydimethylsiloxane, side-chain and both-end modified polydimethylsiloxane, and the like. Examples of the fluorosurfactant include perfluoroalkyl sulfonic acid compounds, perfluoroalkyl carboxylic acid compounds, perfluoroalkyl phosphate ester compounds, perfluoroalkyl ethylene oxide adducts, polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain, and the like. Examples of the amphoteric surfactant include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, and the like. Examples of the nonionic surfactant include polyoxyalkylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkyl amine, polyoxyethylene alkyl amide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, ethylene oxide adduct of acetylene alcohol, and the like. Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, salts of polyoxyethylene alkyl ether sulfate, and the like.

[0030] The content of the surfactant is not particularly limited and is appropriately selected according to the purpose. However, considering wettability, ejection stability, and shaping accuracy, it is preferably 0.001% by mass or more and 5% by mass or less, more preferably 0.01% by mass or more and 3% by mass or less, and still more preferably 0.1% by mass or more and 3% by mass or less based on the total amount of the organic-inorganic composite hydrogel precursor liquid.

[0031] -Colorant- As the colorant, for example, various pigments or dyes that impart colors such as black, white, magenta, cyan, yellow, green, orange, and metallic colors such as gold and silver can be used. As the pigment, an inorganic pigment or an organic pigment can be used. As the inorganic pigment, for example, carbon blacks (C.I. Pigment Black 7) such as furnace black, lamp black, acetylene black, channel black, iron oxide, and titanium oxide can be used. As the organic pigment, for example, azo pigments such as insoluble azo pigments, condensed azo pigments, azo lakes, chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments and other polycyclic pigments, dye chelates (for example, basic dye type chelates, acid dye type chelates, etc.), dyed lakes (for example, basic dye type lakes, acid dye type lakes, etc.), nitro pigments, nitroso pigments, aniline black, daylight fluorescent pigments and the like can be mentioned. In addition, in order to make the dispersibility of the pigment better, a dispersant may be further contained. The dispersant is not particularly limited and can be appropriately selected according to the purpose. For example, dispersants commonly used for preparing pigment dispersions such as polymer dispersants can be mentioned.

[0032] As the dye, for example, acid dyes, direct dyes, reactive dyes, basic dyes and the like can be used, and they can be used alone or in combination of two or more. When used in the material jetting method, full-color shaped objects can be shaped by using materials of various colors such as black, cyan, magenta, yellow, and white. The content of the coloring material is not particularly limited and can be appropriately determined in consideration of the desired color density, dispersibility in the organic-inorganic composite hydrogel precursor liquid, etc. It is preferably 0.1% by mass or more and 20% by mass or less based on the total amount of the organic-inorganic composite hydrogel precursor liquid.

[0033] - Humectant - The humectant is not particularly limited and can be appropriately selected according to the purpose. From the viewpoints of water solubility, moisture retention, and safety, polyhydric alcohols, ethers of polyhydric alcohols and the like can be mentioned. Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-hexanediol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, and the like.

[0034] Examples of ethers of polyhydric alcohols include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, and the like.

[0035] -Other Additives- There are no particular restrictions on other additives, and they can be appropriately selected according to the purpose. Examples include viscosity modifiers, preservatives, pH adjusters, chelating agents, crosslinking agents, polymerization inhibitors, fragrances, antioxidants, crosslinking accelerators, ultraviolet absorbers, plasticizers, and the like.

[0036] The organic-inorganic composite hydrogel precursor solution of the present invention can be prepared using a monomer having a hydroxy group, a borate compound, water, an ionic compound, and other components as required. There are no particular restrictions on the preparation method and conditions, and they can be appropriately selected according to the purpose. For example, each of the above components can be put into a disperser such as a ball mill, a kitty mill, a disk mill, a pin mill, a dyno mill, etc. and mixed to prepare it.

[0037] For the organic-inorganic composite hydrogel precursor solution to perform uniform film formation and high-precision molding, the viscosity at 25 °C is preferably 1 Pa·s or less, more preferably 100 mPa·s or less, and even more preferably 1 mPa·s or more and 20 mPa·s or less. When the viscosity at 25 °C exceeds 1 Pa·s, when bubbles enter the organic-inorganic composite hydrogel precursor solution, it is very difficult to remove the bubbles, and if it hardens as it is, it will have an adverse effect on the quality of the obtained hydrogel molded product. The viscosity can be measured, for example, using a rotational viscometer (VISCOMATE VM-150III, manufactured by Toki Sangyo Co., Ltd.) in an environment of 25 °C.

[0038] (Organic-inorganic composite hydrogel) The organic-inorganic composite hydrogel of the present invention contains a polymer formed by polymerization of a monomer having a hydroxy group, a borate compound, and water, preferably contains an ionic compound and a monomer having an ethylene glycol skeleton, and further contains other components as required. The polymer is a polymer formed by polymerization of a monomer having a hydroxy group in the above organic-inorganic composite hydrogel precursor solution, preferably a monomer having an ethylene glycol skeleton. For the borate compound, ionic compound, water, and other components, the same ones as those of the borate compound, ionic compound, water, and other components in the above organic-inorganic composite hydrogel precursor solution can be used.

[0039] In the present invention, the "hydrogel" refers to a structure in which water is contained in a three-dimensional network structure containing a polymer. When such a three-dimensional network structure is a three-dimensional network structure formed by the complexation of a polymer and an inorganic compound such as a borate compound, it is particularly referred to as an "organic-inorganic composite hydrogel". The hydrogel mainly contains water. Specifically, the water content is preferably 30.0% by mass or more, more preferably 40.0% by mass or more, and still more preferably 50.0% by mass or more based on the total amount of the hydrogel.

[0040] (Method for producing a hydrogel molded article) The method for producing a hydrogel molded article of the present invention includes a liquid film forming step of forming a hydrogel precursor liquid film using the organic-inorganic composite hydrogel precursor liquid of the present invention, and a liquid film hardening step of hardening the hydrogel precursor liquid film to form a layer, and further includes other steps as necessary. The liquid film forming step is preferably performed by an inkjet printing method.

[0041] The method for producing a hydrogel molded article of the present invention is to inject the organic-inorganic composite hydrogel precursor liquid of the present invention into a mold, harden the organic-inorganic composite hydrogel precursor liquid, and then remove the mold to produce a hydrogel molded article.

[0042] Specific examples of the method for producing a hydrogel molded article using the organic-inorganic composite hydrogel precursor liquid of the present invention include the following first to third forms.

[0043] <Method for producing a hydrogel molded article of the first form> The production method of the first form includes repeating a liquid film forming step of forming an organic-inorganic composite hydrogel precursor liquid film and a liquid film hardening step of hardening the organic-inorganic composite hydrogel precursor liquid film to form a layer, laminating the layers to form a hydrogel molded article, and further including other steps as necessary. The liquid film forming step is preferably performed by an inkjet printing method, which is generally referred to as a "material jetting method". The manufacturing method of the hydrogel model object of the first form can simultaneously form colored ink and other resin-based materials by increasing the number of heads, so it can support color forming and hybrid forming with resin-based members. In the manufacturing method of the hydrogel model object of the first form, the above steps are repeated a plurality of times. The number of repetitions varies depending on the size, shape, structure, etc. of the hydrogel object to be formed and cannot be generally defined. However, if the thickness per layer is in the range of 10 μm to 50 μm, it is possible to form accurately without peeling. Therefore, it is preferable to repeat and laminate by the height of the hydrogel object to be formed.

[0044] - Liquid film forming process and liquid film forming means - The liquid film forming process is a process of applying the organic-inorganic composite hydrogel precursor liquid of the present invention to form an organic-inorganic composite hydrogel precursor liquid film, and is carried out by the liquid film forming means.

[0045] There are no particular restrictions on the liquid film forming means, and it can be appropriately selected according to the purpose. For example, a dispenser method, a spray method, an inkjet method, etc. can be mentioned. In addition, known devices can be preferably used to implement these methods. Among these, the dispenser method is excellent in the quantification of liquid droplets, but the coating area becomes narrow. The spray method can easily form fine ejecta, has a wide coating area and excellent coatability, but has poor quantification of liquid droplets and scattering due to the spray flow occurs. Therefore, in the present invention, the inkjet method is particularly preferable. The inkjet method has an advantage that the quantification of liquid droplets is better than that of the spray method, and the coating area can be wider than that of the dispenser method, and is preferable in that a complex three-dimensional shape can be formed accurately and efficiently.

[0046] - Liquid film hardening process and liquid film hardening means - The liquid film hardening process is a process of hardening the organic-inorganic composite hydrogel precursor liquid film to form a layer, and is carried out by the liquid film hardening means. In the liquid film hardening process, the organic-inorganic composite hydrogel precursor liquid film is hardened by irradiating with active energy rays. As the active energy rays, light is preferable, and ultraviolet rays having a wavelength of 220 nm or more and 400 nm or less are particularly preferable. In addition to ultraviolet rays, electron beams, α rays, β rays, γ rays, X rays, etc., may be used as long as they can impart the energy necessary for promoting the polymerization reaction of the polymerizable components in the composition, and are not particularly limited. Particularly when using a high-energy light source, the polymerization reaction can proceed without using a polymerization initiator. In the case of ultraviolet irradiation, mercury-free conversion is strongly desired from the viewpoint of environmental protection, and replacement with a GaN-based semiconductor ultraviolet light-emitting device is very useful industrially and environmentally. Furthermore, ultraviolet light-emitting diodes (UV-LEDs) and ultraviolet laser diodes (UV-LDs) are small, long-lived, highly efficient, and low-cost, and are preferable as ultraviolet light sources.

[0047] As the manufacturing apparatus of the three-dimensional structure by the "material jetting method", commercially available products can be used. Examples of commercially available manufacturing apparatuses for three-dimensional structures by the material jetting method include, for example, Azilisuta (manufactured by Keyence Corporation).

[0048] Here, FIG. 1 shows a three-dimensional printer 10 of the "material jetting method". Using a head unit in which inkjet heads are arranged, an organic-inorganic composite hydrogel precursor liquid is ejected from the liquid material ejection head unit 11 for the shaped body, and a liquid material for forming a support is ejected from the liquid material ejection head units 12, 12 for the support. The organic-inorganic composite hydrogel precursor liquid and the liquid material for forming a support are laminated while being hardened by the adjacent ultraviolet irradiation machines 13, 13. Further, the three-dimensional printer 10 includes a shaped body support substrate 14 and a smoothing member 16. In order to keep the gaps between the liquid material ejection head units 11, 12 and the ultraviolet irradiation machines 13, and the hydrogel shaped body 17 and the support 18 constant, lamination is performed while lowering the stage 15 according to the number of lamination times. In the three-dimensional printer 10, the ultraviolet irradiation devices 13, 13 are used when moving in either direction of the arrows A and B. Due to the heat generated by the ultraviolet irradiation, the surface of the stacked liquid material for forming the support is smoothed, and as a result, the dimensional stability of the hydrogel shaped object can be improved. After the shaping is completed, as shown in FIG. 2, when the hydrogel shaped object 17 and the support 18 are horizontally pulled and peeled off, the support 18 is peeled off integrally, and the hydrogel shaped object 17 can be easily taken out.

[0049] <Method for manufacturing a hydrogel shaped object of the second form> As a method for manufacturing a hydrogel shaped object of the second form, for example, a stereolithography method can be mentioned. The stereolithography method shapes a hydrogel shaped object by sequentially curing and laminating by exposing the organic-inorganic composite hydrogel precursor liquid layer by layer. Each layer of this laminate is obtained by irradiating light onto the liquid surface of the organic-inorganic composite hydrogel precursor liquid. The liquid surface can be leveled with a recoater or the like. At this time, by selectively irradiating light, a cured product (cross-sectional cured layer) having a cross-section of a desired pattern can be obtained. The method for manufacturing a hydrogel shaped object of the second form irradiates light onto the organic-inorganic composite hydrogel precursor liquid to form a cured product (cross-sectional cured layer) of the organic-inorganic composite hydrogel precursor liquid. On top of this cured product (cross-sectional cured layer), the organic-inorganic composite hydrogel precursor liquid is supplied again, irradiated with light, and a cured product (cross-sectional cured layer) of the organic-inorganic composite hydrogel precursor liquid is further formed. Thereafter, by repeating this, a hydrogel shaped object formed by laminating and integrating a plurality of cured products (cross-sectional cured layers) is obtained.

[0050] The means for selectively irradiating light onto the organic-inorganic composite hydrogel precursor liquid is not particularly limited, and various means can be adopted. For example, (a) a means of irradiating the organic-inorganic composite hydrogel precursor liquid while scanning laser light or convergent light obtained using a lens, mirror, etc.; (b) a means of irradiating non-convergent light onto the organic-inorganic composite hydrogel precursor liquid through a mask having a light transmission portion of a predetermined pattern; (c) a means of irradiating light onto the organic-inorganic composite hydrogel precursor liquid through an optical fiber corresponding to a predetermined pattern in a light guiding member formed by bundling a large number of optical fibers; (d) a means of repeatedly performing batch exposure for each fixed region, etc. can be adopted. Also, in the means using the mask in the above (b), as the mask, one that electro-optically forms a mask image composed of a light transmission region and a light non-transmission region according to a predetermined pattern based on the same principle as a liquid crystal display device can also be used.

[0051] When the target hydrogel molded article has fine parts or requires high dimensional accuracy, as a means of selectively irradiating light onto the organic-inorganic composite hydrogel precursor liquid, it is preferable to adopt a means of scanning laser light with a small spot diameter. When the organic-inorganic composite hydrogel precursor liquid is contained in a container, the light irradiation surface (for example, the scanning plane of the convergent light) may be either the liquid surface of the organic-inorganic composite hydrogel precursor liquid or the contact surface with the wall of the light-transmissive container. When the liquid surface of the organic-inorganic composite hydrogel precursor liquid or the contact surface with the wall is used as the light irradiation surface, light can be irradiated directly from the outside of the container or through the wall of the container.

[0052] As described above, the hydrogel shaped article of the present invention can be manufactured by an optical stereolithography method such as a light-based stereolithography method. In the optical stereolithography method, usually, after a specific part of the organic-inorganic composite hydrogel precursor liquid is cured, the irradiation position (irradiation surface) of light is continuously or stepwise moved from the already cured part to the uncured part, and the cured parts are laminated to form a desired three-dimensional shape. Here, the movement of the irradiation position can be performed by various methods. For example, any of the light source, the container for accommodating the organic-inorganic composite hydrogel precursor liquid, and the already cured part of the organic-inorganic composite hydrogel precursor liquid can be moved, or a method of additionally supplying the organic-inorganic composite hydrogel precursor liquid to the container can be used. Commercially available products can be used as the stereolithography apparatus. Examples of commercially available stereolithography apparatuses include Form2 (manufactured by Formlabs).

[0053] <Manufacturing method of the hydrogel shaped article of the third form> The manufacturing method of the hydrogel shaped article of the third form includes a casting method using a mold. In this method, a mold serving as a template is produced. As the method for producing the mold, a 3D printer such as a material jetting method, a stereolithography method, a binder jetting method, an FDM method, etc. can be used. Also, CNC machining may be used. The organic-inorganic composite hydrogel precursor liquid is injected or filled into the internal hollow part of the mold produced by these methods. When the mold is made of a resin having permeability, if the organic-inorganic composite hydrogel precursor liquid is made into a UV-curable type with a photoinitiator, the organic-inorganic composite hydrogel precursor liquid can be easily cured with a UV lamp. When the mold is formed of an impermeable resin, if the organic-inorganic composite hydrogel precursor liquid is made into a thermosetting type with a thermal initiator, the organic-inorganic composite hydrogel precursor liquid can be cured by thermal energy. After the organic-inorganic composite hydrogel precursor liquid is cured by these methods, the hydrogel shaped article can be taken out by peeling the mold or removing it by crushing or the like.

Example

[0054] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to these embodiments at all. In the following examples, the "viscosity of the precursor fluid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel incision property" were carried out as follows.

[0055] <Viscosity of the precursor fluid> The viscosity of the precursor fluid was measured using a TV25 viscometer (manufactured by Toki Sangyo Co., Ltd.). The precursor fluid was measured in a state where the temperature was adjusted at 25 °C for 5 minutes or more.

[0056] <Compression test> - Preparation of compression test specimens (molding) - A polytetrafluoroethylene (PTFE) block was machined to form a test pattern (30 mm × 30 mm × 10 mm), and a mold for preparing compression test specimens was prepared. The precursor fluid was filled into this mold and cured to obtain 30 mm × 30 mm × 10 mm compression test specimens. Note that the curing method is changed depending on the type of initiator added to the precursor fluid. When a thermal polymerization initiator is added, it is left for 24 hours in a nitrogen atmosphere. When a photoinitiator UV is added, it is cured using a UV irradiation device adapted to the polymerization initiator.

[0057] - Measurement of compression stress and Young's modulus - A universal testing machine (manufactured by Shimadzu Corporation, AG-I), a load cell of 1 kN, and a compression jig for 1 kN were provided, and a compression test model was installed. The stress against the compression applied to the load cell was recorded by a computer, the compression stress against the displacement amount was evaluated, and Young's modulus was obtained from the difference between the 70% compression stress, the 10% compression stress, and the 20% compression stress.

[0058] <Tensile test> - Preparation of tensile test specimens (molding) - A test pattern (No. 3 dumbbell shape based on JIS K 6251) was formed to a depth of 3 mm in a polytetrafluoroethylene (PTFE) block by cutting. This mold was filled with a precursor liquid and cured to obtain a tensile test piece. Note that the curing method is changed depending on the type of initiator added to the precursor liquid. When adding a thermal polymerization initiator, it is left for 24 hours in a nitrogen atmosphere. When adding a photoinitiator UV, it is cured using a UV irradiation device corresponding to the polymerization initiator.

[0059] -Measurement of elongation at break and breaking strength- Based on JIS K 6251, a test was conducted using a tensile testing machine (AG-10kNX, manufactured by Shimadzu Corporation) at a tensile speed of 100 mm / min, and from the elongation rate calculated from the change in the distance between the gauge marks, the elongation rate when the tensile test piece broke and the tensile strength at the time of break were determined.

[0060] <Feasibility of X-ray imaging> Using Aquilion one (manufactured by Toshiba Medical Systems Corporation), a diagnostic radiological technologist was asked to take a CT image of the above compression test piece, and it was evaluated according to the following criteria whether sufficient contrast between the outside and the compression test piece could be obtained. [Evaluation criteria] 〇: A CT image with sufficient contrast between the outside and the compression test piece can be taken. ×: X-ray imaging is not possible.

[0061] <Feasibility of incision with an electric scalpel> Using a Martin electric scalpel Maxium (manufactured by KLS Martin Group) in monopolar mode / PureCut, an internist was asked to incise the above compression test piece, and it was evaluated according to the following criteria whether cuttability close to that of a living body could be obtained. [Evaluation criteria] 〇: Incision is possible in a state close to that of a living body. ×: Incision is not possible.

[0062] (Example 1) -Preparation of organic-inorganic composite hydrogel precursor liquid 1- 53.1 parts by mass of ion-exchanged water, 46.0 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.92 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to obtain a hydrogel precursor liquid 1.

[0063] - Fabrication of hydrogel molded article 1 The organic-inorganic composite hydrogel precursor liquid 1 was poured into the mold for preparing the compression test piece and the mold for preparing the tensile test piece, and using a UV-LED irradiator (MS-H1000AF, manufactured by Matsuo Sangyo Co., Ltd.), with the irradiation distance (between the UV lamp and the surface of the organic-inorganic composite hydrogel precursor liquid) set to 40 mm, the hydrogel molded article 1 was fabricated by irradiating with UV light for 15 seconds.

[0064] - Evaluation Regarding the obtained organic-inorganic composite hydrogel precursor liquid 1 and hydrogel molded article 1, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0065] (Example 2) - Preparation of organic-inorganic composite hydrogel precursor liquid 2 77.3 parts by mass of ion-exchanged water, 22.3 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.45 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered by a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor liquid 2.

[0066] -Shaping of the hydrogel structure 2 In the shaping of the hydrogel structure 1, the hydrogel structure 2 was shaped in the same manner as the shaping of the hydrogel structure 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 2.

[0067] -Evaluation Regarding the obtained organic-inorganic composite hydrogel precursor liquid 2 and the hydrogel structure 2, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0068] (Example 3) -Preparation of the organic-inorganic composite hydrogel precursor liquid 3 76.6 parts by mass of ion-exchanged water, 22.1 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 1.33 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the obtained liquid was filtered through a syringe filter (filter pore diameter 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare the organic-inorganic composite hydrogel precursor liquid 3.

[0069] -Shaping of the hydrogel structure 3 In the shaping of the hydrogel structure 1, the hydrogel structure 3 was shaped in the same manner as the shaping of the hydrogel structure 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 3.

[0070] -Evaluation Regarding the obtained organic-inorganic composite hydrogel precursor liquid 3 and the hydrogel structure 3, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0071] (Example 4) -Preparation of Organic-Inorganic Composite Hydrogel Precursor Solution 4 53.1 parts by mass of ion-exchanged water, 46.0 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.92 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor solution 4.

[0072] -Molding of Hydrogel Molded Article 4 In the molding of the hydrogel molded article 1, a hydrogel molded article 4 was molded in the same manner as the molding of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor solution 1 was replaced with the organic-inorganic composite hydrogel precursor solution 4.

[0073] -Evaluation For the obtained organic-inorganic composite hydrogel precursor solution 4 and hydrogel molded article 4, "viscosity of the precursor solution", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0074] (Example 5) -Preparation of Organic-Inorganic Composite Hydrogel Precursor Solution 5 77.3 parts by mass of ion-exchanged water, 22.3 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.45 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor liquid 5.

[0075] - Shaping of the hydrogel molded article 5 In the shaping of the hydrogel molded article 1, the hydrogel molded article 5 was shaped in the same manner as the shaping of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 5.

[0076] - Evaluation For the obtained organic-inorganic composite hydrogel precursor liquid 5 and the hydrogel molded article 5, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0077] (Example 6) - Preparation of the organic-inorganic composite hydrogel precursor liquid 6 76.6 parts by mass of ion-exchanged water, 22.1 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 1.33 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor liquid 6.

[0078] -Shaping of the hydrogel molded article 6 In the shaping of the hydrogel molded article 1, the hydrogel molded article 6 was shaped in the same manner as the shaping of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 6.

[0079] -Evaluation Regarding the obtained organic-inorganic composite hydrogel precursor liquid 6 and the hydrogel molded article 6, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electric scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0080] (Example 7) -Preparation of the organic-inorganic composite hydrogel precursor liquid 7 53.1 parts by mass of ion-exchanged water, 46.0 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.92 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 16.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the obtained liquid was filtered through a syringe filter (filter pore diameter 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare the organic-inorganic composite hydrogel precursor liquid 7.

[0081] -Shaping of the hydrogel molded article 7 In the shaping of the hydrogel molded article 1, the hydrogel molded article 7 was shaped in the same manner as the shaping of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 7.

[0082] -Evaluation Regarding the obtained organic-inorganic composite hydrogel precursor liquid 7 and the hydrogel shaped article 7, the "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0083] (Example 8) - Preparation of organic-inorganic composite hydrogel precursor liquid 8 - 77.3 parts by mass of ion-exchanged water, 22.3 parts by mass of 4-hydroxybutyl acrylate (manufactured by Mitsubishi Chemical Holdings Corporation), 0.45 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 16.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the obtained liquid was filtered through a syringe filter (filter pore diameter 0.8 μm, manufactured by AGC Techno Glass·IWAKI) to prepare an organic-inorganic composite hydrogel precursor liquid 8.

[0084] - Shaping of hydrogel shaped article 8 - In the shaping of the hydrogel shaped article 1, the hydrogel shaped article 8 was shaped in the same manner as the shaping of the hydrogel shaped article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 8.

[0085] - Evaluation - Regarding the obtained organic-inorganic composite hydrogel precursor liquid 8 and the hydrogel shaped article 8, the "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0086] (Example 9) - Preparation of organic-inorganic composite hydrogel precursor liquid 9 - 76.6 parts by mass of ion-exchanged water, 22.1 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 1.33 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 16.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size: 0.8 μm, manufactured by AGC Techno Glass Co., Ltd., Iwaki) to prepare an organic-inorganic composite hydrogel precursor liquid 9.

[0087] - Shaping of hydrogel shaped article 9 In the shaping of the hydrogel shaped article 1, the hydrogel shaped article 9 was shaped in the same manner as the shaping of the hydrogel shaped article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 9.

[0088] - Evaluation For the obtained organic-inorganic composite hydrogel precursor liquid 9 and hydrogel shaped article 9, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cuttability" were evaluated by the above method. The results are shown in Table 2.

[0089] (Example 10) - Preparation of organic-inorganic composite hydrogel precursor liquid 10 53.1 parts by mass of ion-exchanged water, 46.0 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.92 parts by mass of disodium octaborate tetrahydrate (Polybor (registered trademark), manufactured by U.S. Borax), 8.0 parts by mass of sodium chloride (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size: 0.8 μm, manufactured by AGC Techno Glass Co., Ltd., Iwaki) to prepare an organic-inorganic composite hydrogel precursor liquid 10.

[0090] -Molding of the hydrogel molded article 10 In the molding of the hydrogel 1, the hydrogel molded article 10 was molded in the same manner as the molding of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 10.

[0091] -Evaluation For the obtained organic-inorganic composite hydrogel precursor liquid 10 and hydrogel molded article 10, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0092] (Example 11) -Preparation of the organic-inorganic composite hydrogel precursor liquid 11 53.1 parts by mass of ion-exchanged water, 46.0 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.92 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the obtained liquid was filtered through a syringe filter (filter pore diameter 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare the organic-inorganic composite hydrogel precursor liquid 11.

[0093] -Molding of the hydrogel molded article 11 In the molding of the hydrogel 1, the hydrogel molded article 11 was molded in the same manner as the molding of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 11.

[0094] -Evaluation For the obtained organic-inorganic composite hydrogel precursor liquid 11 and hydrogel molded article 11, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0095] (Example 12) -Preparation of Organic-Inorganic Composite Hydrogel Precursor Liquid 12- 53.1 parts by mass of ion-exchanged water, 46.0 parts by mass of 4-hydroxybutyl acrylate (4HBA, manufactured by Mitsubishi Chemical Holdings Corporation), 0.92 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare Organic-Inorganic Composite Hydrogel Precursor Liquid 12.

[0096] -Molding of Hydrogel Molded Article 12- In the molding of Hydrogel Molded Article 1, Hydrogel Molded Article 12 was molded in the same manner as the molding of Hydrogel Molded Article 1, except that Organic-Inorganic Composite Hydrogel Precursor Liquid 1 was replaced with Organic-Inorganic Composite Hydrogel Precursor Liquid 12.

[0097] -Evaluation- For the obtained Organic-Inorganic Composite Hydrogel Precursor Liquid 12 and Hydrogel Molded Article 12, "viscosity of precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0098] (Example 13) -Preparation of Organic-Inorganic Composite Hydrogel Precursor Liquid 13- 58.6 parts by mass of ion-exchanged water, 40.5 parts by mass of hydroxyethyl acrylamide (HEAA, manufactured by KJ Chemicals Co., Ltd.), 0.81 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass & IWAKI Co., Ltd.) to prepare Organic-Inorganic Composite Hydrogel Precursor Liquid 13.

[0099] -Shaping of the hydrogel shaped article 13 In the shaping of the hydrogel shaped article 1, the hydrogel shaped article 13 was shaped in the same manner as the shaping of the hydrogel shaped article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 13.

[0100] -Evaluation Regarding the obtained organic-inorganic composite hydrogel precursor liquid 13 and the hydrogel shaped article 13, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0101] (Example 14) -Preparation of the organic-inorganic composite hydrogel precursor liquid 14 58.7 parts by mass of ion-exchanged water, 40.5 parts by mass of hydroxyethyl acrylamide (HEAA, manufactured by KJ Chemicals Co., Ltd.), 0.81 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the obtained liquid was filtered through a syringe filter (filter pore diameter 0.8 μm, manufactured by AGC Techno Glass·IWAKI Co., Ltd.) to prepare the organic-inorganic composite hydrogel precursor liquid 14.

[0102] -Shaping of the hydrogel shaped article 14 In the shaping of the hydrogel shaped article 1, the hydrogel shaped article 14 was shaped in the same manner as the shaping of the hydrogel shaped article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 14.

[0103] -Evaluation For the obtained organic-inorganic composite hydrogel precursor solution 14 and hydrogel molded article 14, "viscosity of the precursor solution", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0104] (Example 15) - Preparation of organic-inorganic composite hydrogel precursor solution 15 - 58.4 parts by mass of ion-exchanged water, 40.4 parts by mass of hydroxyethyl acrylamide (HEAA, manufactured by KJ Chemicals Co., Ltd.), 0.42 parts by mass of polyethylene glycol #600 diacrylate (A-600, manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.82 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the obtained liquid was filtered through a syringe filter (filter pore diameter 0.8 μm, manufactured by AGC Techno Glass·IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor solution 15.

[0105] - Shaping of hydrogel molded article 15 - In the shaping of the hydrogel molded article 1, the hydrogel molded article 15 was shaped in the same manner as the shaping of the hydrogel molded article 1, except that the organic-inorganic composite hydrogel precursor solution 1 was replaced with the organic-inorganic composite hydrogel precursor solution 15.

[0106] - Evaluation - For the obtained organic-inorganic composite hydrogel precursor solution 15 and hydrogel molded article 15, "viscosity of the precursor solution", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above method. The results are shown in Table 2.

[0107] (Example 16) - Preparation of organic-inorganic composite hydrogel precursor solution 16 - 58.2 parts by mass of ion-exchanged water, 40.2 parts by mass of hydroxyethyl acrylamide (HEAA, manufactured by KJ Chemicals Co., Ltd.), 0.70 parts by mass of polyethylene glycol #1000 diacrylate (A-1000, manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.82 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation), and 0.50 parts by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass·IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor liquid 16.

[0108] - Shaping of hydrogel shaped article 16 In the shaping of the hydrogel shaped article 1, the hydrogel shaped article 16 was shaped in the same manner as the shaping of the hydrogel shaped article 1, except that the organic-inorganic composite hydrogel precursor liquid 1 was replaced with the organic-inorganic composite hydrogel precursor liquid 16.

[0109] - Evaluation For the obtained organic-inorganic composite hydrogel precursor liquid 16 and hydrogel shaped article 16, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0110] (Example 17) - Preparation of KPS aqueous solution 2 parts by mass of potassium peroxodisulfate (KPS, manufactured by Kanto Chemical Co., Inc.) was added to 100 parts by mass of ion-exchanged water and dissolved to obtain a KPS aqueous solution.

[0111] - Preparation of organic-inorganic composite hydrogel precursor liquid 17 58.4 parts by mass of ion-exchanged water, 40.4 parts by mass of hydroxyethyl acrylamide (HEAA, manufactured by KJ Chemicals Co., Ltd.), 0.42 parts by mass of polyethylene glycol #600 diacrylate (A-600, manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.82 parts by mass of sodium tetraborate (trade name: borax, manufactured by Ken-ei Pharmaceutical Co., Ltd.), and 8.0 parts by mass of potassium iodide (manufactured by Fujifilm Wako Pure Chemical Corporation) were stirred, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm, manufactured by AGC Techno Glass·IWAKI Co., Ltd.) to prepare an organic-inorganic composite hydrogel precursor liquid 17.

[0112] - Shaping of the hydrogel molded article 17 - While gently stirring 100 parts by mass of the organic-inorganic composite hydrogel precursor liquid 17, 5 parts by mass of an aqueous KPS solution was added. After confirming sufficient stirring, it was poured into a mold for preparing a compression test piece and a mold for preparing a tensile test piece, vacuum degassed, then nitrogen-substituted, and left at 25 °C for 24 hours (thermosetting agent type molding) to shape the hydrogel molded article 17.

[0113] - Evaluation - Regarding the obtained organic-inorganic composite hydrogel precursor liquid 17 and hydrogel molded article 17, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0114] (Example 18) - Shaping of the hydrogel molded article 18 - Using the organic-inorganic composite hydrogel precursor liquid 15 as the model material ink and a 3D printer of the material jet method (MJ), MateriART-3DU (manufactured by Microjet Co., Ltd.), a compression test piece of 30 mm × 30 mm × 10 mm and a dumbbell-shaped No. 3 tensile test piece with a thickness of 3 mm were shaped as the hydrogel molded article 18.

[0115] - Evaluation - For the obtained hydrogel shaped article 18, the "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0116] (Example 19) -Shaping of Hydrogel Shaped Article 19 Using the organic-inorganic composite hydrogel precursor liquid 15 as a shaping ink and a Form2 (manufactured by Formlabs), a 3D printer of the stereolithography (SLA) method, a compression test piece of 30 mm × 30 mm × 10 mm and a dumbbell-shaped No. 3 tensile test piece with a thickness of 3 mm were shaped in the open mode as the hydrogel shaped article 19.

[0117] -Evaluation For the obtained hydrogel shaped article 19, the "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2.

[0118] (Comparative Example 1) -Preparation of KPS Aqueous Solution To 100 parts by mass of ion-exchanged water, 2 parts by mass of potassium peroxodisulfate (KPS, manufactured by Kanto Chemical Co., Inc.) was added and dissolved to obtain a KPS aqueous solution.

[0119] -Preparation of Hydrogel Shaped Article 101 In a nitrogen-substituted desiccator, to 19 parts by mass of ion-exchanged water, laponite XLG [Mg 5.34 Li 0.66 Si 8 O 20 (OH) 4 Na + 0.660.66 parts by mass of a water-swellable synthetic hectorite (manufactured by Nippon Silica Co., Ltd.) having the composition was added and stirred to prepare a colorless and transparent solution. To this, 1.5 parts by mass of dimethylacrylamide (DMAA, manufactured by KJ Chemicals Co., Ltd.) was added, and subsequently, 1.0 part by mass of the KPS aqueous solution and 0.5 part by mass of dimethylaminoethyl acrylate (DMAEA, manufactured by Fujifilm Wako Pure Chemical Corporation) were added with stirring to obtain a homogeneous solution. The obtained homogeneous solution was poured into the mold for preparing the compression test piece and the mold for preparing the tensile test piece, the upper part was sealed, and it was allowed to stand and polymerize at 20 °C for 15 hours to obtain a hydrogel 101.

[0120] - Preparation of borate-based organic-inorganic composite hydrogel 101 - The hydrogel 101 was immersed in 100 mL of a 5 mass% borate-based aqueous solution for 3 days in step 1 and then immersed in 100 mL of pure water for 1 day in step 2, and this process was repeated 3 times to obtain a borate-based organic-inorganic composite hydrogel 101. All water was bubbled with high-purity nitrogen for 3 hours or more to remove dissolved oxygen. Laponite XLG was vacuum-dried at 80 °C for 24 hours, and DMAA and DMAEA were used after removing polymerization inhibitors using activated alumina (manufactured by Fujifilm Wako Pure Chemical Corporation).

[0121] - Evaluation - For the obtained borate-based organic-inorganic composite hydrogel 101, "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel cutability" were evaluated by the above method. The results are shown in Table 2. The borate-based organic-inorganic composite hydrogel 101 is a colorless and transparent cured product with flexibility, and the elongation at break is sufficiently large. However, the hydrogel swelled due to immersion, and the cross-section of the tensile test piece changed in shape from a width of 5 mm × thickness of 3 mm to a width of 7.3 mm × thickness of 4.1 mm.

[0122] (Comparative Example 2) - Preparation of Photoinitiator Solution - As a photopolymerization initiator solution, a photopolymerization initiator (Irgacure 184, manufactured by BASF) was dissolved at a ratio of 4 parts by mass with respect to 96 parts by mass of ethanol and prepared as an aqueous solution.

[0123] - Preparation of Organic-Inorganic Composite Hydrogel Precursor Liquid 102 - While stirring 165 parts by mass of pure water, 20 parts by mass of synthetic hectorite having a composition of [Mg 5.34 Li 0.66 Si 8 O 20 (OH) 4 Na + 0.66 (manufactured by RockWood, Laponite XLG) was added little by little and stirred to prepare a dispersion. Next, 0.8 part by mass of an aqueous solution of etidronic acid (Chrest PH-210, active ingredient content 60% by mass, manufactured by Chrest Co., Ltd.) was added to the obtained dispersion. After dispersion for 30 minutes, 20 parts by mass of the synthetic hectorite was further added little by little and stirred for 30 minutes. A total of 40 parts by mass of the synthetic hectorite was added. Thereafter, the dispersion was stored in a constant temperature bath at 50 °C for 10 hours to stabilize the dispersion. Next, 20 parts by mass of acryloylmorpholine (ACMO, manufactured by KJ Chemicals Co., Ltd.) from which a polymerization inhibitor had been removed by passing through a column of activated alumina as a monomer and 30 parts by mass of glycerin were added to the obtained dispersion. Further, 1.0 part by mass of Emulgen S LS-106 (manufactured by Kao Corporation) was added as a surfactant and mixed. Next, while cooling in an ice bath, 2.2 parts by mass of the above photopolymerization initiator solution and 0.15 part by mass of tetraethylmethylenediamine (manufactured by Fujifilm Wako Pure Chemical Corporation) were added, stirred and mixed, and then degassing under reduced pressure was carried out for 20 minutes. Subsequently, impurities and the like were removed by filtration to prepare an organic-inorganic composite hydrogel precursor liquid 102.

[0124] - Preparation of Hydrogel 102 - The organic-inorganic composite hydrogel precursor solution 102 is poured into the mold for preparing the compression test piece and the mold for preparing the tensile test piece. Using a UV-LED irradiator (MS-H1000AF, manufactured by Matsuo Sangyo Co., Ltd.), with the irradiation distance (between the UV lamp and the hydrogel precursor solution surface) set to 40 mm, the hydrogel 102 was obtained by irradiating UV light for 15 seconds.

[0125] - Preparation of Aqueous Potassium Iodide Solution - 100 parts by mass of potassium iodide (KI, manufactured by Fujifilm Wako Pure Chemical Corporation) was added to 100 parts by mass of ion-exchanged water and dissolved to prepare an aqueous potassium iodide solution.

[0126] - Shaping of Potassium Iodide-Containing Hydrogel 102 - The hydrogel 102 was immersed in 300 mL of an aqueous potassium iodide solution for 3 days in Step 1 and then in 300 mL of ion-exchanged water for 1 day in Step 2. This process was repeated 3 times to shape the potassium iodide-containing hydrogel 102.

[0127] - Evaluation - For the obtained potassium iodide-containing hydrogel 102, "compression test", "tensile test", "X-ray imaging property", and "electrical scalpel incision property" were evaluated by the above method. The results are shown in Table 2. The potassium iodide-containing hydrogel 102 is a brownish-yellow cured product with flexibility and a large elongation at break. However, the hydrogel swelled due to immersion, and the cross-section of the tensile test piece changed in shape from a width of 5 mm × thickness of 3 mm to a width of 8.7 mm × thickness of 4.9 mm.

[0128] (Comparative Example 3) - Preparation of Silicone Gel Precursor Solution 103 - Hydroxyethyl acrylamide (HEAA, manufactured by KJ Chemicals Co., Ltd.) and triethyl borate (manufactured by Tokyo Chemical Industry Co., Ltd.) were mixed at a molar ratio of 3:1, and the mixture was heated and stirred at 50 °C using a rotary evaporator to remove ethanol, resulting in HEAA-borate. The obtained HEAA-borate blend was degassed at 4 kPa (40 mbar) for 1 hour in a vacuum desiccator. 31.5 parts by mass of HEAA-borate, 47.2 parts by mass of 3-[tris(trimethylsiloxy)silyl]propyl methacrylate (SiGMA, manufactured by Tokyo Chemical Industry Co., Ltd.), 20.0 parts by mass of tert-amyl alcohol, 1.0 part by mass of ethylene glycol dimethacrylate, and 0.3 part by mass of 2-hydroxy-2-methylpropiophenone (Irgacure 1173, manufactured by BASF) were mixed, and the resulting liquid was filtered through a syringe filter (filter pore size 0.8 μm) to prepare a silicone gel precursor liquid 103.

[0129] -Molding of silicone gel molded article 103- The silicone gel precursor liquid 103 was poured into the above-mentioned mold for preparing a compression test piece and the mold for preparing a tensile test piece. Using a UV-LED irradiator (MS-H1000AF, manufactured by Matsuo Sangyo Co., Ltd.), with the irradiation distance (UV lamp and the surface of the hydrogel precursor liquid) set to 40 mm, the silicone gel 103 was molded by irradiating UV light for 15 seconds.

[0130] -Evaluation- Regarding the obtained silicone gel precursor liquid 103 and silicone gel 103, "viscosity of the precursor liquid", "compression test", "tensile test", "X-ray imaging property", and "scalpel incision property" were evaluated by the above methods. The results are shown in Table 2. The silicone gel 103 was a colorless and transparent cured product, a gel with flexibility and affinity for water, but the elongation at break in the tensile test was small.

[0131] Next, the compositions and molding methods of Examples 1 to 19 are summarized in Table 1.

[0132]

Table 1

[0133] The detailed contents of the abbreviations in Table 1 are as follows. *4HBA: 4-hydroxybutyl acrylate, manufactured by Mitsubishi Chemical Holdings Corporation *HEAA: Hydroxyethylacrylamide, manufactured by KJ Chemicals Co., Ltd. *A-600: Polyethylene glycol #600 diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd. *A-1000: Polyethylene glycol #1000 diacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd.

[0134]

Table 2

[0135] From the results in Table 2, the organic-inorganic composite hydrogel precursor liquids of Examples 1 to 19 had low viscosities, so no bubbles remained even without degassing in a vacuum desiccator. Also, when a compression test was performed on the obtained hydrogel molded article, sufficient compressive stress was obtained, and it was not broken even when compressed at 1 MPa. Furthermore, when the obtained hydrogel molded article was evaluated by a tensile test, it was found that the elongation rate at break was large and the extensibility was high. In Comparative Example 1, since the hydrogel molded article 101 was immersed in an aqueous solution of an inorganic boric acid compound to introduce a borate group into the hydrogel molded article, a shape change due to swelling occurred, which was inferior compared to the hydrogel molded article 1. In Comparative Example 3, the obtained gel was a silicone hydrogel and did not contain water, so it was harder than the hydrogel molded article 1 and no elongation was obtained.

[0136] Also, the organic-inorganic composite hydrogel precursor liquids of Examples 4 to 9 and 14 to 19 had low viscosities, so no bubbles remained even without degassing in a vacuum desiccator. In addition to the fact that the obtained hydrogel molded articles were as excellent as the hydrogel molded articles of Examples 1 to 3 in terms of the characteristics of the compression test and the tensile test, it was found that they could be cut with an electric scalpel and contrast could be obtained by X-ray imaging. In Comparative Example 2, when an ionic compound was added to the organic-inorganic composite hydrogel precursor liquid 102, it became unstable and gelled, so an ionic compound could not be stably contained like the organic-inorganic composite hydrogel precursor liquid 4 of Example 4. In addition, since the hydrogel molded article 10 of Example 10 used sodium chloride as the ionic compound, contrast could not be obtained in X-ray imaging, but it could be cut with a scalpel.

[0137] As aspects of the present invention, for example, they are as follows. <1> A monomer having a hydroxy group, a borate compound, water, and an organic-inorganic composite hydrogel precursor liquid characterized by containing the same. <2> The organic-inorganic composite hydrogel precursor liquid according to <1> above, wherein the borate compound is at least one of sodium tetraborate and disodium octaborate tetrahydrate. <3> The organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <2> above, wherein the content of the borate compound is 0.1% by mass or more and 20% by mass or less. <4> The organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <3> above, wherein the monomer having a hydroxy group is at least one of 4-hydroxybutyl acrylate and hydroxyethyl acrylamide. <5> The organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <4> above, which contains an ionic compound. <6> The organic-inorganic composite hydrogel precursor liquid according to <5> above, wherein the content of the ionic compound is 0.1% by mass or more and 20% by mass or less. <7> The organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <6> above, which contains a monomer having an ethylene glycol skeleton. <8> The organic-inorganic composite hydrogel precursor liquid according to <7> above, wherein the monomer having an ethylene glycol skeleton is a polyfunctional monomer. <9> A hydrogel molded article obtained by using the organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <8> above. <10> A method for manufacturing a hydrogel molded article, which comprises injecting the organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <8> into a mold, curing the organic-inorganic composite hydrogel precursor liquid, and then removing the mold to obtain the hydrogel molded article. <11> A liquid film forming step of forming a hydrogel precursor liquid film using the organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <8>, and a liquid film curing step of curing the hydrogel precursor liquid film to form a layer, The method for manufacturing a hydrogel molded article is characterized by including these steps. <12> The method for manufacturing a hydrogel molded article according to <11>, wherein the liquid film forming step is performed by an inkjet printing method. <13> An organic-inorganic composite hydrogel characterized by containing a polymer formed by polymerization of a monomer having a hydroxy group, a borate compound, and water.

[0138] According to the organic-inorganic composite hydrogel precursor liquid according to any one of <1> to <8>, the hydrogel molded article according to <9>, the method for manufacturing a hydrogel molded article according to any one of <10> to <12>, and the organic-inorganic composite hydrogel according to <13>, various problems in the prior art can be solved, and the object of the present invention can be achieved.

Explanation of Symbols

[0139] 10 Three-dimensional printer 17 Hydrogel molded article

Prior Art Documents

Patent Documents

[0140]

Patent Document 1

Patent Document 2

Patent Document 3

Claims

1. A monomer having a hydroxy group and a radically polymerizable functional group, A borate compound which is at least one of sodium tetraborate and disodium octaborate tetrahydrate, Water, A radical polymerization initiator, comprising the number of the radically polymerizable functional groups in the monomer having a hydroxy group and a radically polymerizable functional group is one, and the radically polymerizable functional group is an acryloyl group or an acrylamide group, the content of the monomer having a hydroxy group and a radically polymerizable functional group is 5% by mass or more and 50% by mass or less, the content of the borate compound is 0.1% by mass or more and 20% by mass or less, an organic-inorganic composite hydrogel precursor liquid in which the content of the water is 40% by mass or more, the organic-inorganic composite hydrogel precursor liquid does not contain a monomer having an ethylene glycol skeleton, a monomer having no hydroxy group and ethylene glycol skeleton, and a crosslinking agent. An organic-inorganic composite hydrogel precursor liquid characterized by that.

2. A monomer having a hydroxy group and a radically polymerizable functional group, A borate compound which is at least one of sodium tetraborate and disodium octaborate tetrahydrate, Water, A radical polymerization initiator, comprising the number of the radically polymerizable functional groups in the monomer having a hydroxy group and a radically polymerizable functional group is one, and the radically polymerizable functional group is an acryloyl group or an acrylamide group, the content of the monomer having a hydroxy group and a radically polymerizable functional group is 5% by mass or more and 50% by mass or less, the content of the borate compound is 0.1% by mass or more and 20% by mass or less, an organic-inorganic composite hydrogel precursor liquid in which the content of the water is 40% by mass or more, the organic-inorganic composite hydrogel precursor liquid does not contain a monomer having no hydroxy group and ethylene glycol skeleton and a crosslinking agent, contains a monomer having an ethylene glycol skeleton, and the content of the monomer having an ethylene glycol skeleton is 0.01 or more and 0.5 or less in molar ratio when the monomer having a hydroxy group and a radically polymerizable functional group is taken as 1. An organic-inorganic composite hydrogel precursor liquid characterized by that.

3. The organic-inorganic composite hydrogel precursor liquid according to claim 2, wherein the monomer having an ethylene glycol skeleton is a polyfunctional monomer.

4. The monomer having the hydroxy group and the radically polymerizable functional group is at least one of 4-hydroxybutyl acrylate and hydroxyethyl acrylamide. The organic-inorganic composite hydrogel precursor liquid according to any one of claims 1 to 3.

5. The organic-inorganic composite hydrogel precursor liquid according to any one of claims 1 to 4, containing an ionic compound.

6. The organic-inorganic composite hydrogel precursor liquid according to claim 5, wherein the content of the ionic compound is 0.1% by mass or more and 20% by mass or less.

7. A hydrogel shaped article obtained by using the organic-inorganic composite hydrogel precursor liquid according to any one of claims 1 to 6.

8. A method for producing a hydrogel shaped article, comprising injecting the organic-inorganic composite hydrogel precursor liquid according to any one of claims 1 to 6 into a mold, curing the organic-inorganic composite hydrogel precursor liquid, and then removing the mold.

9. A liquid film forming step of forming a hydrogel precursor liquid film using the organic-inorganic composite hydrogel precursor liquid according to any one of claims 1 to 6, A liquid film curing step of curing the hydrogel precursor liquid film to form a layer, A method for producing a hydrogel shaped article, characterized by including.

10. The method for producing a hydrogel shaped article according to claim 9, wherein the liquid film forming step is performed by an inkjet printing method.

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