JP7067778B2 - Photochromic complex - Google Patents

Description

The present invention relates to a photochromic composite containing tungsten oxide, titanium oxide and a water-soluble polymer compound, a photochromic material, a solution for forming a photochromic composite, an ultraviolet indicator using the photochromic composite, and a method for producing the photochromic composite. Regarding.

Electrochromism with tungsten oxide (WO ₃ ) was introduced in 1973 by S.A. K. First reported by Deb, it has been studied for the purpose of developing electro-displays as display elements in place of CRT displays. Initially, unlike the light-emitting type such as CRT, it is easy to see even in direct sunlight, and there is no dependence on the viewing angle compared to liquid crystal displays, so there are great expectations for the development of new display systems. However, it was found that it cannot be used for monitor systems such as televisions, which require high speed, due to its slow response speed. Therefore, it has been expanded to research for the purpose of controlling and utilizing solar energy that does not require high-speed responsiveness, and with increasing awareness of environmental issues, research on expansion to smart windows has been conducted, and now Then, tungsten oxide is used for electronic curtains mounted on aircraft windows. In a smart window, the light transmittance of the window can be controlled by adjusting the voltage, but the problem is that it requires electrical energy.

Further, regarding tungsten oxide, a property of changing to blue by absorbing ultraviolet rays, that is, a proposal for an application utilizing photochromism has been made. A transparent film containing tungsten oxide, cellulose, and ethylene glycol turns dark blue by itself under sunlight in the summer and returns to transparent the next day. It has been proposed to use it as a possible photochromic film (Patent Document 1). This film is a cellulose compound whose main component is a biomaterial, and is a film that is easy to dispose of even for an amateur. Further, since only the portion irradiated with light becomes blue, application to rewritable paper that can be erased as a display material by clarifying the contrast between transparent and dark blue has been proposed. However, since the intensity of coloring depends on the amount of absorbed ultraviolet rays, there is a problem that the color development in the morning is weak when used as the dimming film, for example. Further, in the application to rewritable paper, there is a problem in use that an artificial strong ultraviolet irradiator is required for clear contrast display. As described above, the conventional photochromic film using tungsten oxide requires irradiation with strong ultraviolet rays to develop a deep blue color, and it takes time for the dark blue color to be visually recognized under sunlight irradiation. There was a problem.

On the other hand, the result of observing the state of color development by mixing tungsten oxide sol and titanium oxide sol has been reported (Non-Patent Document 1). However, what has been reported is the state of color development in the sol (colloidal aqueous solution) state, and further, the color is not developed in the air, but is developed only in the atmosphere of nitrogen or argon. Therefore, no proposal was made for a photochromic material that develops color in the air, or a photochromic complex in the shape of a film or a molded body.

Japanese Unexamined Patent Publication No. 2014-62218

S. Yamazaki, et al., Colloids and Surfaces A: Physicochem. Eng. Aspects. 2011, 392, 163-170.

An object of the present invention is to solve the above-mentioned problems and to provide a photochromic composite which has excellent photoresponsiveness and develops color even under relatively weak ultraviolet irradiation, and particularly a photochromic composite which rapidly develops color even under natural sunlight. The challenge is to provide the body.

In order to solve the above problems, the present inventors have developed a material that quickly develops a deep blue color even under natural sunlight irradiation, and that does not require a special atmosphere and develops a deep blue color even under air. We proceeded with diligent research aiming at. Conventionally, in a photochromic material, the transparency is lowered when other metal oxide particles are added to tungsten oxide, so that the use of a mixture of tungsten oxide and other metal oxide particles has not been tried much. However, when the present inventors use a mixture of tungsten oxide particles and titanium oxide particles and further mix a water-soluble polymer compound such as cellulose, the transparency is lowered, but the speed and color development in response to light are increased. We have found that the optical responsiveness such as intensity is extremely improved. In addition, the complex composed of these components is less affected by air and exhibits excellent photoresponsiveness in the sun in the air, that is, in the normal natural state, and thus is different from the conventional one. It was possible to apply it to applications. In this way, the invention of the present application is completed.

That is, the present invention is specified by the following matters.
(1) A photochromic complex containing tungsten oxide, titanium oxide and a water-soluble polymer compound.
(2) The photochromic complex according to (1) above, wherein the water-soluble polymer compound is alkyl cellulose.
(3) The photochromic complex according to (1) or (2) above, which contains a water-soluble compound having a hydroxy group (however, excluding the water-soluble polymer compound described in (1) above).
(4) The photochromic complex according to (3) above, wherein the water-soluble compound having a hydroxy group is an alcohol or an organic acid.
(5) The photochromic complex according to (4) above, wherein the alcohol is ethylene glycol.
(6) An ultraviolet indicator using the photochromic complex according to any one of (1) to (5) above.
(7) A photochromic material containing tungsten oxide, titanium oxide and a water-soluble polymer compound for use in anti-counterfeiting.
(8) A solution for forming a photochromic complex containing tungsten oxide particles, titanium oxide particles, and a water-soluble polymer compound.
(9) A method for producing a photochromic composite, which comprises preparing a dispersion liquid containing tungsten oxide particles, titanium oxide particles and a water-soluble polymer compound, applying the dispersion liquid onto a substrate, and drying the dispersion liquid.
(10) A method for producing a photochromic composite, which comprises preparing a dispersion liquid containing tungsten oxide particles, titanium oxide particles and a water-soluble polymer compound, filling the dispersion liquid in a mold, and drying the dispersion liquid.

The photochromic composite of the present invention has excellent photoresponsiveness and develops color even under relatively weak ultraviolet irradiation, and particularly rapidly develops color even under sunlight irradiation in the air. In addition, the method for producing a photochromic complex of the present invention can easily produce a photochromic complex exhibiting photochromism as described above.

It is a photograph of the photochromic film produced in Example 1. (A) is an example in which methyl cellulose is added, and (b) is an example in which polyvinyl alcohol is added. It is a photograph of the photochromic bulk body produced in Example 2. (A) is an example in which the molar ratio of W and Ti is 1: 1 and (b) is an example in which the molar ratio of W and Ti is 1: 1 and ethylene glycol is added in addition to methyl cellulose. c) is an example in which the molar ratio of W and Ti is 1: 3, and (d) is an example in which the molar ratio of W and Ti is 3: 1. It is a photograph of the photochromic film produced in Example 3. (A) is an example in which the molar ratio of W and Ti is 1: 1 and (b) is an example in which the molar ratio of W and Ti is 1: 1 and ethylene glycol is added in addition to methyl cellulose. c) is an example in which the molar ratio of W and Ti is 1: 3, and (d) is an example in which the molar ratio of W and Ti is 3: 1. It is a photograph of the photochromic film produced in Example 4. (A) is before the ultraviolet irradiation of the example to which methyl cellulose is added, and (b) is after the ultraviolet irradiation of the example to which methyl cellulose is added. (C) is before the ultraviolet irradiation of the example to which TEMPO oxide CNF is added, and (d) is after the ultraviolet irradiation of the example to which TEMPO oxide CNF is added. It is a photograph of the photochromic bulk body produced in Example 4. (A) is before the start of sunlight irradiation, (b) is 10 seconds after the start of sunlight irradiation, (c) is 20 seconds after the start of sunlight irradiation, and (d) is 30 seconds after the start of sunlight irradiation. (E) is 1 minute after the start of sunlight irradiation. Further, (f) is an example in which TiO ₂ is not added. It is a photograph of the photochromic bulk body prepared by the solution of Example 3 and the photochromic bulk body prepared by Example 4. (A) is before the start of sunlight irradiation, (b) is 10 seconds after the start of sunlight irradiation, (c) is 20 seconds after the start of sunlight irradiation, and (d) is 1 minute after the start of sunlight irradiation. Is. It is a photograph of the photochromic film produced in Example 3. (A) is before sunlight irradiation, (b) is 10 seconds after the start of sunlight irradiation, and (c) and (d) are 1 minute after the start of sunlight irradiation. Measurement results of the film produced in the same manner as in Example 3 by the diffuse reflection method before and after ultraviolet irradiation.

The photochromic composite of the present invention is a photochromic composite containing tungsten oxide, titanium oxide and a water-soluble polymer compound, and contains tungsten oxide, titanium oxide and a water-soluble polymer compound as essential components. The photochromic complex of the present invention is a complex exhibiting photochromism, and its shape is not particularly limited, and examples thereof include a film-like shape and a molded body-like shape. Here, the film-like form includes a form formed on a base material and attached to the base material, and a form which is not fixed to the base material and is used alone as a so-called film. The tungsten oxide in the present invention is not particularly limited, but for example, those obtained by ion exchange of an aqueous solution of a salt of tungsten can be preferably exemplified. Further, the titanium oxide in the present invention is not particularly limited, but for example, those obtained by hydrolyzing titanium alkoxide can be preferably exemplified.

The water-soluble polymer compound in the present invention is not particularly limited, and examples thereof include natural water-soluble polymer compounds, semi-synthetic water-soluble polymer compounds, and synthetic water-soluble polymer compounds. can. In the photochromic composite of the present invention, the tungsten oxide particles and the titanium oxide particles can be uniformly dispersed by blending the water-soluble polymer compound, and the water-soluble polymer compound acts as a binder component.

Examples of natural water-soluble polymer compounds include plants such as Arabic gum, tragacant gum, galactan, guar gum, carob gum, karaya gum, carrageenan, pectin, canten, quince seed (malmero), algae colloid (casso extract), starch, and glycyrrhizinic acid. Polymers; Micromolecular polymers such as xanthan gum, dextran, succinoglucan, and purulan; Animal polymers such as collagen, casein, albumin, and gelatin can be mentioned. Examples of the semi-synthetic water-soluble polymer compound include starch-based polymer compounds such as carboxymethyl starch and methyl hydroxypropyl starch; alkyl cellulose such as methyl cellulose and ethyl cellulose; hydroxyalkyl cellulose such as hydroxyethyl cellulose and hydroxypropyl cellulose; methyl. Hydroxyalkylalkyl celluloses such as hydroxypropyl cellulose; Cellulose-based polymer compounds such as nitrocellulose, sodium cellulose sulfate, sodium carboxymethyl cellulose (CMC), crystalline cellulose, TEMPO oxidized cellulose nanofibers, cellulose powder; sodium alginate, propylene glycol alginate ester. And the like, alginic acid-based polymers can be mentioned. Examples of the synthetic water-soluble polymer compound include vinyl polymer compounds such as polyvinyl alcohol, polyvinyl methyl ether polymer, polyvinylpyrrolidone, and carboxyvinyl polymer; polyethylene glycol 20,000, polyethylene glycol 6,000, and polyethylene glycol. Polyoxyethylene-based polymer compounds such as 4,000; Polyoxyethylene polyoxypropylene copolymers, copolymerization-based polymer compounds such as PEG / PPG methyl ether; Sodium polyacrylate, polyethyl acrylate, polyacrylamide, etc. Acrylic polymer compounds can be mentioned. These can be used alone or in admixture of two or more. Of these, alkyl cellulose is preferable, and methyl cellulose is particularly preferable. The weight average molecular weight (Mw) of these water-soluble polymer compounds is not particularly limited as long as the complex of the present invention can be prepared, but those of 500 to 500,000,000, preferably water-soluble, are more preferable. It is 1,000 to 500,000.

The photochromic complex of the present invention may contain a water-soluble compound having a hydroxy group (excluding those compounded as the above-mentioned water-soluble polymer compound). The water-soluble compound having a hydroxy group in the present invention is a compound having a relatively low molecular weight other than the above-mentioned water-soluble polymer compound, and by adding these, the photoresponsiveness is further improved and the photoresponsiveness is further improved in response to light. Color develops quickly. In addition, the flexibility of the complex is improved and the transparency is improved. The water-soluble compound having a hydroxy group is an organic compound as long as it has one or more hydroxy groups, is water-soluble, and preferably does not evaporate when the film is dried at room temperature to about 40 ° C. However, it may be an inorganic compound. For example, examples of the organic compound include hydrocarbons and organic acids having a hydroxy group which may have an oxygen atom as a linking group, and examples of the inorganic compound include phosphoric acid and boric acid. Acids can be mentioned. Of these, alcohols and organic acids are preferable.

Examples of the "hydrocarbon" of the "hydrocarbon having a hydroxy group" include aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons and the like. Examples of aliphatic hydrocarbons include alkanes such as ethyl, propane, butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, heptadecane and octadecane; ethylene, propylene, butene, pentene, hexene and octene. , Nonen, decene, butadiene, isoprene and the like; alkynes such as ethine, propine, butine, pentene and the like can be mentioned. Examples of the alicyclic hydrocarbon include cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene and the like.

Alcohols are exemplified below as water-soluble compounds having a hydroxy group. Examples of the alcohols in the present invention include water-soluble polyhydric alcohols having 2 or more carbon atoms, preferably 2 to 30 carbon atoms. A monohydric alcohol is also possible as long as it is water-soluble and does not evaporate at room temperature to about 40 ° C. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, glycerin, neopentylene glycol, trimethylolpropane, pentaerythritol, hexanetriol, ditrimethylolpropane, dipentaerythritol, trihydroxystearyl alcohol and 3-butene. Aliper alcohols such as -1-ol; cyclic alcohols such as cyclopentanetriol, cyclohexanetriol and cyclohexanehexaol can be mentioned. These can be used alone or in admixture of two or more, and preferably have a boiling point of 100 ° C. or higher. It is more preferable to contain a divalent or trivalent alcohol, and ethylene glycol and glycerin are further preferable.

Examples of the aromatic hydrocarbon include benzene and naphthalene, and examples of the water-soluble aromatic hydrocarbon having a hydroxy group include phenol, catechol, pyrogallol and the like. A hydrocarbon having an oxygen atom as a linking group means a compound having one or more oxygen atoms in the molecule of the hydrocarbon. Examples of the hydrocarbon having a hydroxy group and having an oxygen atom as a linking group include saccharides such as glucose and maltose.

Organic acids are exemplified below as water-soluble compounds having a hydroxy group. Examples of the organic acids in the present invention include carboxylic acids or sulfonic acids having 1 or more carbon atoms, preferably 1 to 10 carbon atoms. Examples of the carboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid and n-heptanoic acid. 2-Methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid. Examples thereof include acid, malic acid, tartrate acid, citric acid and the like. Examples of sulfonic acids include methanesulfonic acid, trifluoromethanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, camphorsulfonic acid and the like. These can be used alone or in admixture of two or more, with monohydroxycarboxylic acids or dicarboxylic acids being preferred, and glycolic acid and oxalic acid being even more preferred.

The ratio of each component of tungsten oxide, titanium oxide and the water-soluble polymer compound in the composite of the present invention is not particularly limited as long as the composite of the present invention can be formed, but can improve the strength of the composite. From the viewpoint of improving the photoresponsiveness, the water-soluble polymer compound is preferably 30 to 150 parts by weight, more preferably 50 to 100 parts by weight, based on 100 parts by weight of the total of tungsten oxide and titanium oxide. When the amount of the water-soluble polymer compound added is larger than the above range, the strength of the composite of the present invention is increased, but the viscosity is increased and air is contained, and the white turbidity of the composite becomes stronger. On the other hand, if the amount of the water-soluble polymer compound added is less than the above range, the strength of the complex becomes weak. When a water-soluble compound having a hydroxy group is blended, the water-soluble compound having a hydroxy group makes the complex easy to handle and further improves photochromism, so that the total weight of tungsten oxide and titanium oxide is 100 parts by weight. On the other hand, 20 to 200 parts by weight is preferable. If the amount of the water-soluble compound having a hydroxy group added is more than the above range, the complex to be formed contains a large amount of water, which makes the complex difficult to handle. On the other hand, if the amount added is less than the above range, the effect of improving the photochromism of the complex and the effect of improving the flexibility and transparency cannot be sufficiently obtained.
When the water-soluble compound having a hydroxy group is an alcohol, the alcohol / tungsten oxide (molar ratio) is, for example, 1. In the case of glycerin / WO ₃ , from the viewpoint of further improving the photoresponsiveness of the complex. 0 or more is preferable, in the case of ethylene glycol / WO ₃ , 2.0 or more is preferable, and 3.0 or more is more preferable. When alcohols are used, the alcohol / tungsten oxide (molar ratio) is preferably 6 or less from the viewpoint of maintaining the strength of the complex. When the water-soluble compound having a hydroxy group is an organic acid, the organic acid / tungsten oxide (molar ratio) is, for example, 0 in the case of oxalic acid / WO ₃ from the viewpoint of further improving the photoresponsiveness of the complex. .1 to 0.2 is preferable, and in the case of glycolic acid / WO ₃ , 0.2 to 0.8 is preferable.
The content ratio of tungsten oxide and titanium oxide in the composite of the present invention is not particularly limited, but from the viewpoint of further improving the photoresponsiveness, the molar ratio of tungsten (W) to titanium (Ti) is W. : Ti = 4: 1 to 1: 3, more preferably 3: 1 to 1: 3, and even more preferably 3: 1 to 1: 2.

(Manufacturing method of photochromic complex)
The method for producing the complex of the present invention is not particularly limited, but for example, a solution for forming a photochromic complex containing tungsten oxide, titanium oxide and a water-soluble polymer compound is prepared, and the solution is used as a base material. It can be produced by applying it on top and drying it, or by filling it in a mold and drying it by pouring it. In the former case, a film-like complex can be produced, and in the latter case, a molded product can be produced. The solution for forming a photochromic composite in the present invention is preferably a dispersion containing tungsten oxide particles, titanium oxide particles and a water-soluble polymer compound, in which the tungsten oxide particles and titanium oxide particles are dispersed.

(Preparation of photochromic complex formation solution)
The complex-forming solution containing tungsten oxide particles, titanium oxide particles and a water-soluble polymer compound is, for example, a mixture of a tungsten oxide colloidal solution and a titanium oxide colloidal solution, and the water-soluble polymer compound is mixed with the mixed colloidal solution. Can be prepared by In mixing these, heating, stirring, ultrasonic treatment, etc. are performed as necessary. In the preparation of the complex forming solution, it is preferable to use a colloidal aqueous solution of tungsten oxide and a colloidal aqueous solution of titanium oxide in order to uniformly disperse the tungsten oxide particles and the titanium oxide particles in the complex forming solution. As the colloidal aqueous solution of tungsten oxide, for example, an aqueous solution of a tungsten salt such as sodium tungstate that has been ion-exchanged (Na ⁺ → H ⁺ ) can be used. The concentration of tungsten oxide in the colloidal aqueous solution is not particularly limited, but can be, for example, about 0.01 to 0.60 mol / L, preferably about 0.01 to 0.20 mol / L. .. As the colloidal aqueous solution of titanium oxide, for example, one obtained by hydrolyzing titanium alkoxide can be used, and if necessary, one obtained by degluing the alkoxide can be used. The concentration of titanium oxide in the colloidal aqueous solution is not particularly limited, but can be, for example, about 0.01 to 0.60 mol / L, preferably about 0.01 to 0.20 mol / L. .. The concentration of the tungsten oxide colloidal aqueous solution or the titanium oxide colloidal aqueous solution can be determined by inductively coupled plasma emission spectroscopic analysis or the like. The tungsten oxide colloidal aqueous solution and the titanium oxide colloidal aqueous solution prepared in this manner are mixed, and the water-soluble polymer compound is mixed with the mixed colloidal aqueous solution. The concentration of the water-soluble polymer compound in the complex-forming solution is not particularly limited as long as the complex can be formed, but can be, for example, about 0.1 to 10% by weight. Further, if necessary, a water-soluble compound having a hydroxy group is mixed. The concentration of the water-soluble compound having a hydroxy group in the complex-forming solution is not particularly limited as long as the complex can be formed, but can be, for example, about 0.1 to 10% by weight. The compounding ratio of each component in the complex-forming solution is the same as the compounding ratio of each component in the complex.

(Preparation of photochromic complex)
Using the complex-forming solution prepared above, a photochromic complex can be prepared by a conventionally known method. For example, in the case of producing a photochromic film, a solution for forming a composite film is applied onto a glass or Teflon (registered trademark) substrate by a conventionally known method, formed into a film by means such as printing, and then dried and gelled. Can be produced by. As the drying conditions, the alcohols may be dried at a temperature at which they do not evaporate, and may be dried under normal pressure in a temperature range of room temperature to 40 ° C., or may be heated and dried if alcohols that do not easily evaporate are used. The base material used for producing the film is not particularly limited, and for example, a conventionally known base material including an inorganic base material such as glass or metal or an organic base material such as resin can be used. The photochromic composite film of the present invention has a sufficient thickness for durability, but for the purpose of further enhancing the durability and obtaining new physical properties such as adhesiveness to glass or the like, a protective layer or a protective layer is provided. Other layers such as an adhesive layer can be provided. When the other layer is provided, the layer may be provided on the upper part and / or the lower part of the composite film of the present invention, and the composition of the other layer is applied at the same time as the constituent components of the composite film of the present invention. A film may be formed. Further, in the case of producing a photochromic molded product, the complex-forming solution prepared above is poured into a mold and dried to produce a molded product having a predetermined shape. The base material used for the mold, the drying temperature, etc. are the same as in the case of producing the film. Since the photochromic complex of the present invention, for example, a photochromic film or a photochromic molded product, has excellent photochromism by ultraviolet rays, it can be used as an ultraviolet indicator indicating the amount of exposed ultraviolet rays. Further, when the photochromic film of the present invention is formed on an object for which anti-counterfeiting is desired, the color is developed under sunlight, so that the authenticity of the object can be determined and it can be used for anti-counterfeiting. Here, the film includes a film formed in various patterns, and can be printed using a photochromic complex forming solution, or the complex can be embedded in a fiber or the like. As described above, the photochromic complex forming solution and the photochromic complex of the present invention can be used as a photochromic material for use in preventing counterfeiting.

Hereinafter, the present invention will be described in more detail in Examples, but the technical scope of the present invention is not limited thereto. In the examples, the concentration of tungsten oxide or titanium oxide in the sol is measured by using an inductively coupled plasma emission spectrophotometer (Liberty Series II manufactured by Varian), and the particle size is measured by a transmission electron microscope. (JEM-2100 manufactured by JEOL Ltd.) was used.

[Example 1]
₍ Preparation of WO3 sol)
Na ₂ WO _{4.2H 2} O was measured in 15.831 g and dissolved in 100 mL of water. While stirring 90 mL of this aqueous solution on a stirrer, 9.5 mL of hydrochloric acid (9.3M) was added dropwise. 25 mL of the obtained solution was evenly placed in 4 dialysis membranes (12 cm) having a molecular weight cut off of 3500 that had been washed in advance, and dialyzed in 1 L of water for 8 hours to remove chloride ions to remove tungsten oxide sol (WO ₃ ). Zol) was obtained. The water was replaced with a new one every hour. The WO ₃ concentration in the sol was 0.16 M, and the particle size of the WO ₃ particles was in the range of 10 to 20 nm.

(Preparation of TiO ₂ sol)
1.3 mL of nitric acid was added to 180 mL of water, and the mixture was stirred on a stirrer. 15 mL of titanium tetraisopropoxide was added dropwise, and then stirring was continued for 6 days in a dark place. Titanium oxide sol obtained by deflocculation was evenly placed in 4 dialysis membranes (12 cm) having a molecular weight cut off of 3500 at 25 mL each and dialyzed in 1 L of water for 8 hours to obtain titanium oxide sol (TIO ₂ sol). The water was replaced with a new one every hour. The pH of the water at the end of dialysis was 3.96. It was also confirmed by ion chromatography that nitrate ions were completely removed by dialysis for 8 hours. The TiO ₂ concentration in the sol was 0.19 M, and the particle size of the TiO ₂ particles was in the range of 10 nm or less.

(Making a photochromic film)
The WO ₃ sol and the TiO ₂ sol prepared above were diluted with water to prepare 0.016 MWO ₃ sol and 0.016 MTIO ₂ sol, respectively. 10 mL each was mixed to make a 20 mL solution (molar ratio: W: Ti = 1: 1). To this mixed sol solution, 0.4 g (2 wt%) of methyl cellulose (MC400) or 0.6 g (3 wt%) of polyvinyl alcohol (PVA) was added as a water-soluble polymer, and 0.027 mL of ethylene glycol (EG) was added. (Mole ratio is EG / WO ₃ = 3.0) was added, and the mixture was stirred in a hot water bath (55 to 63 ° C.), subjected to ultrasonic treatment, and further stirred to obtain a uniform solution. This solution was placed in a hydrophobically treated petri dish (inner diameter: 9.5 cm) and dried at 40 ° C. for 2 days. The resulting film was transparent. FIG. 1 shows a photograph of the appearance of the obtained film. FIG. 1 (a) is a film obtained from a solution to which methyl cellulose was added, and FIG. 1 (b) is a film obtained from a solution to which polyvinyl alcohol was added.

[Example 2]
(Making a photochromic bulk body (lump))
The TiO ₂ sol prepared in the same manner as in Example 1 was diluted with water to prepare a 0.16 MTIO ₂ sol. 10 mL each of 0.16 MWO ₃ sol and 0.16 MTIO ₂ sol were mixed to obtain a 20 mL solution (molar ratio: W: Ti = 1: 1). Further, 20 mL of a mixed sol of W: Ti = 1: 3 and W: Ti = 3: 1 was prepared by changing the volume ratio of the WO ₃ sol and the TiO ₂ sol to be mixed. 0.4 g (2 wt%) of methyl cellulose (MC400) as a water-soluble polymer was added to each mixed sol solution, and the mixture was stirred in a hot water bath (55 to 63 ° C.), sonicated, and further stirred. A homogeneous solution was obtained. Further, 0.27 ml of ethylene glycol (EG) is added to the mixed sol having a molar ratio of W: Ti = 1: 1 (mole ratio EG / WO ₃ = 3.0). Was added, and the mixture was stirred in a hot water bath (55 to 63 ° C.), sonicated, and further stirred to prepare a uniform solution. The obtained solutions were transferred to each hydrophobically treated beaker (inner diameter 3.5 cm) and dried at 40 ° C. for 2 days. All became white lumps, but when EG was added, they were highly flexible and soft lumps. FIG. 2 shows a photograph of the appearance of the obtained mass. FIG. 2A shows a mass obtained from a solution [WO ₃ / TiO ₂ / MC (W: Ti = 1: 1)] to which a molar ratio W: Ti = 1: 1 and methyl cellulose is added. FIG. 2B has a molar ratio of W: Ti = 1: 1 and is obtained from a solution [WO ₃ / TIO ₂ / MC / EG (W: Ti = 1: 1)] to which methyl cellulose and ethylene glycol are added. FIG. 2 (c) shows a lump having a molar ratio of W: Ti = 1: 3 and is obtained from a solution [WO ₃ / TiO ₂ / MC (W: Ti = 1: 3)] to which methyl cellulose is added. FIG. 2 (d) shows a lump having a molar ratio of W: Ti = 3: 1 and is obtained from a solution [WO ₃ / TiO ₂ / MC (W: Ti = 3: 1)] to which methyl cellulose is added. It is a lump.

[Example 3]
₍ Preparation of WO3 sol)
A WO ₃ sol was prepared in the same manner as in Example 1. The WO ₃ concentration in the WO ₃ sol was 0.15 M.

(Preparation of TiO ₂ sol)
The TiO ₂ sol obtained by gluing was evenly placed in two dialysis membranes (15 cm) having a molecular weight cut off of 3500 in an amount of 49 ml, and dialyzed in 1.75 L of water for 3 days while exchanging water once a day. A TiO ₂ sol was obtained in the same manner as in Example 1 except for the above. The TiO ₂ concentration in the TiO ₂ sol was 0.17 M.

(Making a photochromic film)
The WO ₃ sol and the TiO ₂ sol prepared above were diluted with water to prepare 0.14 MWO ₃ sol and 0.14 MTIO ₂ sol, respectively. 10 ml each was mixed to obtain a 20 ml solution (molar ratio: W: Ti = 1: 1). Further, 20 ml of a mixed sol of W: Ti = 1: 3 and W: Ti = 3: 1 was prepared by changing the volume ratio of the WO ₃ sol and the TiO ₂ sol to be mixed. 0.4 g (2 wt%) of methyl cellulose (MC400) as a water-soluble polymer is added to each mixed sol solution, and the mixture is stirred in a hot water bath (55 to 63 ° C.), ultrasonically treated, and further stirred. To obtain a uniform solution. Further, 0.4 g (2 wt%) of methyl cellulose (MC400) was added to a mixed sol of WO ₃ sol and TiO ₂ sol (molar ratio: W: Ti = 1: 1), and 0.27 ml of ethylene glycol (molar ratio EG) was added. / WO ₃ = 3.0) was added, and the mixture was stirred in a hot water bath (55 to 63 ° C.), sonicated, and further stirred to obtain a uniform solution. The obtained solutions were placed in a petri dish (inner diameter: 9.5 cm) subjected to hydrophobic treatment and dried at 40 ° C. for 1 day to obtain a cloudy film. FIG. 3 shows a photograph of the appearance of the obtained film. FIG. 3A is a film obtained from a solution [WO ₃ / TiO ₂ / MC (W: Ti = 1: 1)] to which a molar ratio W: Ti = 1: 1 and methyl cellulose is added. FIG. 3B shows a molar ratio W: Ti = 1: 1 and a solution containing methyl cellulose and ethylene glycol [WO ₃ / TiO ₂ / MC / EG (W: Ti = 1: 1, EG / WO ₃ ). = 3.0)], and FIG. 3 (c) shows a solution having a molar ratio of W: Ti = 1: 3 and a methyl cellulose added solution [WO ₃ / TiO ₂ / MC (W: Ti). = 1: 3)], and FIG. 3 (d) shows a solution having a molar ratio of W: Ti = 3: 1 and a methyl cellulose added solution [WO ₃ / TiO ₂ / MC (W: Ti). = 3: 1)].

(Color development test of films and lumps obtained in Examples 1 to 3)
The films and lumps obtained in Examples 1 to 3 were irradiated with ultraviolet rays using a pen-type ultraviolet irradiator (AS ONE MOS-Cure mini 365 UV wavelength: 365 nm), and the state of color development was visually observed. Both the films and the lumps obtained in Examples 1 to 3 developed a blue color by irradiating with ultraviolet rays. The film obtained in Example 1 was transparent because the content of WO ₃ and TiO ₂ in the solution used for film preparation was small, but the color development intensity was not stronger than that of Examples 2 and 3. .. The intensity of color development in the mass obtained in Example 2 was strongest when ethylene glycol was added (W: Ti = 1: 1), followed by (W: Ti = 3: 1) and (W: Ti). = 1: 1) was about the same, and (W: Ti = 1: 3) was next. As for the intensity of color development in the film obtained in Example 3, the one to which ethylene glycol was added (W: Ti = 1: 1) was the strongest, followed by (W: Ti = 3: 1), as in Example 2. 1) and (W: Ti = 1: 1) were almost the same, and (W: Ti = 1: 3) was next. Regarding the dialysis time of the TiO ₂ sol, no difference was observed in the color development intensity between 8 hours and 3 days.

[Example 4]
(Preparation of WO ₃ sol and TIO ₂ sol)
In the same manner as in Example 3, a WO ₃ sol having a WO ₃ concentration of 0.12 M and a TiO ₂ sol having a TiO ₂ concentration of 0.12 M were obtained.

(Making a photochromic film)
The WO ₃ sol and the TIO ₂ sol prepared above were mixed by 10 mL each (molar ratio: W: Ti = 1: 1). Methyl cellulose (MC400) 2.0 wt% or TEMPO oxide CNF (cellulose nanofiber) 0.7 wt% is added as a water-soluble polymer to the mixed sol solution, and the mixture is stirred in a hot water bath (55 to 63 ° C.). Then, ultrasonic treatment and further stirring were performed to obtain a uniform solution. The obtained solutions were placed in a petri dish (inner diameter: 9.5 cm) subjected to hydrophobic treatment, and dried at 30 ° C. for 46 hours. A white film was obtained. Here, TEMPO is 2,2,6,6-tetramethylpiperidin1-oxyl. Further, a mass (molar ratio: W: Ti = 1: 1) was prepared from the solution to which methyl cellulose was added in the same manner as in Example 2.

(Color development test of film and mass obtained in Example 4)
The film obtained in Example 4 was irradiated with ultraviolet rays using a pen-type ultraviolet irradiation device (AS ONE MOS-Cure mini 365 UV wavelength: 365 nm). FIG. 4 is a photograph showing the result (state of color development). FIG. 4 (a) shows the film obtained from the solution to which methyl cellulose was added before UV irradiation, and FIG. 4 (b) shows after UV irradiation. FIG. 4 (c) shows the film obtained from the solution to which TEMPO oxide CNF was added before UV irradiation, and FIG. 4 (d) shows after UV irradiation. Both quickly developed a blue color when irradiated with ultraviolet rays using a pen-type ultraviolet irradiator. In addition, the mass produced in Example 4 was placed in sunlight on a sunny day (50% of clouds were present) to perform a color development test. FIG. 5 is a photograph showing the result (state of color development). 5 (a) is before the sun irradiation, FIG. 5 (b) is 10 seconds after the start of the sun irradiation, and FIG. 5 (c) is 20 seconds after the start of the sun irradiation. (D) is 30 seconds after the start of sunlight irradiation, and FIG. 5 (e) is 1 minute after the start of sunlight irradiation. Further, in FIG. 5 (f), 2 wt% of methyl cellulose and 0.45 g of ethylene glycol (molar ratio of ethylene glycol / WO ₃ is 3) are added to 20 mL of WO ₃ sol having a WO ₃ concentration of 0.12 M. It is a photograph of a transparent film prepared by stirring in a hot water bath (55 to 63 ° C.), ultrasonically treated, and further stirred with a uniform solution 2 minutes after the start of sunlight irradiation. The mass obtained from the photochromic material of the present invention develops a blue color 10 seconds after the start of sunlight irradiation and a deep blue color 1 minute after the start of sunlight irradiation, so that the responsiveness at the time of light irradiation is very high. fast. On the other hand, in the transparent film containing no TIO ₂ , only pale blue color was observed even 2 minutes after the start of light irradiation.

(Color development test under sunlight-1)
The mass (thickness 2 mm) obtained from the [WO ₃ / TiO ₂ / MC (W: Ti = 1: 1)] solution prepared in Example 4 and the [WO ₃ / TiO ₂ /] prepared in Example 3 A mass (thickness 0) obtained after placing the MC / EG (W: Ti = 1: 1, EG / WO ₃ = 3.0)] solution in a 100 mL beaker (bottom diameter 5 cm) and drying at 40 ° C. for 2 days. .4 mm) was placed in sunlight on a cloudy day (80% of the clouds were present) to perform a color development test. FIG. 6 is a photograph showing the result (state of color development). 6 (a) is before the start of sunlight irradiation, FIG. 6 (b) is 10 seconds after the start of sunlight irradiation, and FIG. 6 (c) is 20 seconds after the start of sunlight irradiation. (D) is one minute after the start of sunlight irradiation. The left side of the photograph is the mass of Example 4. Due to the cloudy weather, the mass of Example 4 1 minute after the start of sunlight irradiation had a weaker color development than the case of FIG. 5 (e), but the one to which ethylene glycol was added became dark blue and had very high photoresponsiveness. It was fast.

(Color development test under sunlight-2)
A film prepared in Example 3 having a molar ratio of W: Ti = 1: 1 and obtained from a solution [WO ₃ / TiO ₂ / MC (W: Ti = 1: 1)] to which methyl cellulose (MC) was added. The molar ratio W: Ti = 1: 1 and the solution to which methyl cellulose and ethylene glycol (EG) were added [WO ₃ / TiO ₂ / MC / EG (W: Ti = 1: 1, EG / WO ₃ = 3). The film obtained from [.0)] was placed in sunlight on a cloudy day (80% of clouds were present) to perform a color development test. Both films were obtained by drying in a petri dish with a diameter of 9.5 cm and have a thickness of approximately 60 μm. FIG. 7 is a photograph showing the result (state of color development). 7 (a) is before the start of solar irradiation, FIG. 7 (b) is 10 seconds after the start of solar irradiation, and FIG. 7 (c) is 1 minute after the start of solar irradiation. When the left side is [WO ₃ / TiO ₂ / MC (W: Ti = 1: 1)], the right side of the photo is [WO ₃ / TiO ₂ / MC / EG (W: Ti = 1: 1, EG / WO ₃ )]. = 3.0)]. FIG. 7 (d) shows on the film in the case of [WO ₃ / TiO ₂ / MC / EG (W: Ti = 1: 1, EG / WO ₃ = 3.0)] 1 minute after the start of sunlight irradiation. This is a photograph of the purple tape that had been attached before the start of the test. When ethylene glycol was added, the color development speed was much faster than when ethylene glycol was not added, and the color became deep blue 1 minute after the start of sunlight irradiation (FIG. 7 (c)). From FIG. 7 (d), it can be seen that only the portion irradiated with sunlight develops a blue color. Further, in FIG. 8, an ultra-high pressure mercury lamp (18 mW / cm) is formed on a film having a thickness of about 68 μm of [WO ₃ / TiO ₂ / MC (W: Ti = 1: 1)] prepared in the same manner as in Example 3. The film after being irradiated with ultraviolet rays for 5 minutes in ² ) and the film before being irradiated with ultraviolet rays are subjected to the diffusion reflection method (measuring device: ultraviolet-visible-infrared spectrophotometer, JASCO, JASCO V-670, integrating sphere unit (measurement device: ultraviolet-visible-infrared spectrophotometer, V-670, integrating sphere unit). The results measured by ISN-723) are shown. From this result, it can be seen that the composite (film) of the present invention develops a blue color when irradiated with ultraviolet rays.

Since the photochromic composite of the present invention has excellent photochromism by ultraviolet rays, it is used in the field of visualizing the amount of ultraviolet rays in sunlight, for example, in containers such as sunscreen creams, sunshades, hats and other daytime ultraviolet rays countermeasure products. It can be used as an indicator of the amount of exposed ultraviolet rays. In addition, since the color develops quickly in sunlight, the authenticity of the product can be proved by exposing it to sunlight, and it can be used in the field of anti-counterfeiting.

Claims (7)

A photochromic complex containing tungsten oxide, titanium oxide , a water-soluble polymer compound and ethylene glycol . The photochromic complex according to claim 1, wherein the water-soluble polymer compound is alkyl cellulose. An ultraviolet indicator using the photochromic complex according to claim 1 or 2 . A photochromic material containing tungsten oxide, titanium oxide and a water-soluble polymer compound for use in anti-counterfeiting. A solution for forming a photochromic complex containing tungsten oxide particles, titanium oxide particles , a water-soluble polymer compound and ethylene glycol . A method for producing a photochromic composite, which comprises preparing a dispersion liquid containing tungsten oxide particles, titanium oxide particles , a water-soluble polymer compound and ethylene glycol , applying the dispersion liquid onto a substrate, and drying the dispersion liquid. A method for producing a photochromic composite, which comprises preparing a dispersion liquid containing tungsten oxide particles, titanium oxide particles , a water-soluble polymer compound and ethylene glycol , filling the dispersion liquid in a mold, and drying the dispersion liquid.

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