JP2024065697A - Electrochromic sheet and electrochromic device - Google Patents

Abstract

[Problem] To improve the processability of an electrochromic sheet. [Solution] An electrochromic sheet 100 of the present invention comprises a first support layer 1, an electrolyte layer 4 provided on the first support layer 1, a first electrochromic layer 3 provided on at least one side of the electrolyte layer 4, and a sealing portion 8 provided so as to cover at least the side surface of the electrolyte layer 4, and has a deformation amount measured in the following procedure i of 0.01 mm to 0.09 mm. Procedure i: Using the electrochromic sheet 100, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer 4 as the center and the sealing portion 8 as the outer edge, both ends of the test piece are chucked with chucking portions, and the center of the test piece is pressed with 30 N for 30 seconds, and the difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is taken as the deformation amount (mm). [Selected Figure] Figure 1

Description

The present invention relates to an electrochromic sheet and an electrochromic device.

Electrochromic elements are known as elements that utilize electrochromism, a phenomenon in which a reversible oxidation-reduction reaction occurs when a voltage is applied, resulting in a reversible change in transmittance. For example, applying a positive voltage to an electrochromic element causes it to develop color, and applying a negative voltage causes it to become decolorized and transparent. Therefore, by providing a switch that can switch between applying a positive voltage and a negative voltage, it becomes possible to cause the electrochromic element to develop color and decolor at any time.

Such electrochromic elements can be broadly divided into two types of layer configurations. One is a layer configuration in which an electrochromic material and an electrolyte material are mixed, and the other is a multi-layer configuration in which an electrochromic material and an electrolyte material are formed as separate layers. In the latter multi-layer electrochromic element, the electrochromic material is fixed in layers, so the charge injected into the electrochromic material undergoes a reverse reaction through an external circuit. This has the advantage that once color is generated, the colored state can be maintained until the decolorization drive is performed, reducing power consumption.

An example of an electrochromic device that uses a gel electrolyte is described in Patent Document 1. Patent Document 1 discloses an electrolyte solution having a Tg of less than about -40°C that contains at least one bifunctional redox dye dissolved in an ionic liquid solvent.

International Publication No. 2004/001877

The inventors have found that the electrochromic device disclosed in Patent Document 1 has a gel electrolyte layer sealed inside, and therefore tends to be easily recessed in the stacking direction of the electrolyte layer during processing.

As a result of extensive research into improving the processability of electrochromic sheets, the inventors discovered that it is effective to use the amount of deformation when electrochromically pressed under specific conditions as an indicator and control this, thus completing the present invention.

According to the present invention, the following electrochromic sheet and related technology are provided.

[1] A support layer;
an electrolyte layer provided on the support layer;
an electrochromic layer provided on at least one surface of the electrolyte layer;
a sealing portion provided so as to cover at least a side surface of the electrolyte layer;
An electrochromic sheet comprising:
The electrochromic sheet has a deformation of 0.01 mm to 0.09 mm as measured by the following procedure i.
Step i: Using the electrochromic sheet, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer as the center and the sealing portion as the outer edge, both ends of the test piece are chucked with chucking portions, and the center of the test piece is pressed with 30 N for 30 seconds, and the difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is the deformation amount (mm).
[2] The electrochromic sheet according to [1],
An electrochromic sheet having a deformation of 0.10 mm or less as measured by the following procedure ii.
Step ii: Using the electrochromic sheet, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer as the center and the sealing portion as the outer edge, both ends of the test piece are chucked with chucking portions, and the center of the test piece is pressed with 50 N for 30 seconds, and the difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is the deformation amount (mm).
[3] The electrochromic sheet according to [1],
In step i, an electrochromic sheet having no yield point.
[4] The electrochromic sheet according to [2],
In step ii), an electrochromic sheet having no yield point.
[5] The electrochromic sheet according to any one of [1] to [4],
The electrochromic sheet, wherein the electrolyte layer is a solid or a gel.
[6] The electrochromic sheet according to any one of [1] to [5],
The electrochromic sheet, wherein the electrolyte layer includes a binder resin.
[7] The electrochromic sheet according to [6],
The electrochromic sheet, wherein the binder resin comprises one or more resins selected from the group consisting of urethane (meth)acrylate, polymethyl (meth)acrylate, polyethyl (meth)acrylate, and poly(ethylene oxide)acrylate.
[8] The electrochromic sheet according to any one of [1] to [7],
An electrochromic sheet, the electrochromic layer being provided on the upper and lower surfaces of the electrolyte layer of the electrochromic sheet.
[9] The electrochromic sheet according to any one of [1] to [8],
The sealing portion is formed using a sealing material containing a curable resin.
[10] The electrochromic sheet according to [9],
The electrochromic sheet, wherein the curable resin has at least one selected from an ultraviolet-reactive functional group and a heat-reactive functional group.
[11] The electrochromic sheet according to any one of [1] to [10],
The electrochromic sheet further comprises an electrode layer between the support layer and the electrochromic layer.
[12] An electrochromic device using the electrochromic sheet according to any one of [1] to [11].

The present invention provides an electrochromic sheet with improved processability.

1 is a cross-sectional view showing a schematic diagram of an electrochromic sheet according to an embodiment of the present invention. FIG. 2 is a diagram showing displacement-load curves obtained in the examples and comparative examples.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
In order to avoid complication, when there are multiple identical components in the same drawing, only one of them may be labeled with a symbol, and not all of them may be labeled with a symbol. The drawings are for explanatory purposes only. The shapes and dimensional ratios of each component in the drawings do not necessarily correspond to the actual products.

In this specification, the notation "a to b" in the explanation of a numerical range means from a to b, unless otherwise specified. For example, "1 to 5 mass%" means "1 mass% to 5 mass%." In addition, the lower limit and upper limit of a numerical range can be arbitrarily combined with the lower limit and upper limit of another numerical range.

Unless otherwise specified, each of the components and materials exemplified in this specification may be used alone or in combination of two or more types.

In this embodiment, "covering" does not necessarily mean being continuous, but may mean having discontinuous parts.

<Electrochromic sheet>
FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of an electrochromic sheet 100. As shown in FIG.
As shown in FIG. 1, the electrochromic sheet 100 comprises a laminate (hereinafter also referred to as "electrochromic element 10") in which an electrolyte layer 4, a first electrochromic layer 3, and a second electrochromic layer 5 are laminated in that order, a sealing portion 8 covering the side surfaces of the electrochromic element 10, and a pair of support layers (a first support layer 1 and a second support layer 7) sandwiching the upper and lower surfaces of the electrochromic element 10 and the sealing portion 8 therebetween.
In other words, the electrochromic sheet 100 comprises a first electrochromic layer 3, an electrolyte layer 4, a second electrochromic layer 5, and a second support layer 7, which are stacked in sequence on a first support layer 1, and the sides of the first electrochromic layer 3, the electrolyte layer 4, and the second electrochromic layer 5 are each covered by a sealing portion 8.

In this embodiment, the electrochromic sheet 100 further includes a first electrode 2 between the first support layer 1 and the first electrochromic layer 3, and a second electrode 6 between the second support layer 7 and the second electrochromic layer 5.

In addition, in FIG. 1, an electrochromic sheet 100 having one electrochromic element 10 partitioned by a sealing portion 8 is described, but the electrochromic sheet may be long and have multiple electrochromic elements 10 partitioned by sealing portions 8. In this case, the electrochromic sheet is punched in its thickness direction to separate each electrochromic element 10, and the electrochromic sheet 100 shown in FIG. 1 can be obtained. For example, when processing an optical lens using the electrochromic sheet 100, the sheet is punched into a shape that approximates the planar view of the lens. The outer edge of the lens is formed by the sealing portion 8, and the planar area of the electrochromic element 10 corresponds to the viewing area of the lens.

The electrochromic sheet 100 of this embodiment has a deformation amount of 0.01 mm to 0.09 mm as measured in the following procedure i.
Step i: Using the electrochromic sheet 100, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer 4 at the center and the sealing portion 8 at the outer edge, both ends of the test piece are chucked with the chucking portions, and the center of the test piece is pressed with 30 N for 30 seconds. The difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is the deformation amount (mm).

This improves the workability of the electrochromic sheet 100. More specifically, even when a load is applied to the electrolyte layer 4, for example, during punching or deformation of the electrochromic sheet 100 into a curved shape, during surface processing to make prescription lenses, or during chucking during lens cutting, deformation or denting of the electrolyte layer 4 can be suppressed.

Furthermore, it is preferable that the electrochromic sheet 100 does not have a yield point in step i. This allows for more stable and good processability.

Moreover, the electrochromic sheet 100 of this embodiment has a deformation amount of 0.10 mm or less when measured in the following procedure ii.
Step ii: Using the electrochromic sheet 100, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer 4 at the center and the sealing portion 8 at the outer edge, both ends of the test piece are chucked with the chucking portions, and the center of the test piece is pressed with 50 N for 30 seconds. The difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is the deformation amount (mm).

Furthermore, it is preferable that the electrochromic sheet 100 does not have a yield point in step ii. This allows for more stable and good processability.

In steps i and ii above, the shape of the test piece is adjusted appropriately according to the shape of the electrolyte layer 4 and the sealing portion 8 covering the side surface of the electrolyte layer 4, but the maximum length is at least 20 mm. If the shape of the test piece is rectangular, it is preferable that one side is 20 mm or more and the other side is 30 mm or more. There is no particular upper limit to the shape of the test piece, and it is sufficient that it does not protrude from the stage of the measuring device. The central portion is the area including the center point of the test piece in a plan view.

The electrochromic sheet 100 that satisfies the above conditions can be realized by devising the material and manufacturing procedure of the electrolyte layer described below. For example, this can be achieved by controlling the type and content of the binder resin of the electrolyte, the use of the ionic liquid described below, and the content thereof.

Each component is explained below.

[Electrolyte layer]
The electrolyte layer 4 is disposed between the first electrochromic layer 3 and the second electrochromic layer 5, and contains an electrolyte having ion conductivity.

The average thickness of the electrolyte layer 4 is not particularly limited, but is preferably set to about 10 μm or more and 100 μm or less, more preferably 20 μm or more and 80 μm or less, and even more preferably 30 μm or more and 70 μm or less.

The electrolyte filled as the electrolyte layer 4 may be either solid or liquid, but in addition to the case where the electrolyte is a low-viscosity liquid, it can take various forms, such as a gel, a polymer cross-linked type, or a liquid crystal dispersion type. Of these, it is preferable to form the electrolyte layer 4 in a gel or solid state. This can improve the element strength and reliability of the electrochromic element 10.

A preferred method for making the electrolyte layer 4 solid is, for example, a method in which a liquid containing an electrolyte and a solvent is held in a binder resin, which makes it possible to obtain both high ionic conductivity and solid strength of the electrolyte layer 4.
In addition, the binder resin is preferably, for example, a photocurable resin, which allows the solid electrolyte layer 4 to be obtained at a lower temperature and in a shorter time than when the solid electrolyte layer 4 is obtained by thermal polymerization or evaporation of a solvent.

The electrolyte layer 4 of the present embodiment preferably contains a binder resin and an electrolyte.
Each material contained in the electrolyte layer 4 will now be described in detail.

(Electrolytes)
The electrolyte is not particularly limited, but may be a solid electrolyte, an ionic liquid, or the like.

Solid Electrolyte The solid electrolyte is not particularly limited, and examples thereof include inorganic ion salts such as alkali metal salts and alkaline earth metal salts, quaternary ammonium salts, acids, and alkali supporting salts, etc. Specific examples thereof include LiClO ₄ , LiBF ₄ , LiAsF ₆ , LiPF ₆ , LiCF ₃ SO ₃ , LiCF ₃ COO, KCl, NaClO ₃ , NaCl, NaBF ₄ , NaSCN, KBF ₄ , Mg(ClO ₄ ) ₂ , and Mg(BF ₄ ) ₂ , and one or more of these may be used in combination.

Ionic Liquids Ionic liquids are electrolytic liquids. Among them, organic ionic liquids are preferably used because they have a molecular structure that allows them to remain liquid over a wide temperature range, including room temperature, and are therefore easy to handle.

As the molecular structure of the organic ionic liquid, examples of the cationic component include imidazole derivatives such as N,N-dimethylimidazole salt, N,N-methylethylimidazole salt, and N,N-methylpropylimidazole salt; pyridinium derivatives such as N,N-dimethylpyridinium salt and N,N-methylpropylpyridinium salt; and aliphatic quaternary ammonium salts such as trimethylpropylammonium salt, trimethylhexylammonium salt, and triethylhexylammonium salt. In addition, in consideration of stability in the atmosphere, it is preferable to use a fluorine-containing compound as the anionic component, such as BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , PF ₄ ⁻ , and (CF ₃ SO ₂ ) ₂ N ⁻ .

The material for such an electrolyte is preferably an ionic liquid that contains any combination of cationic and anionic components.

The ionic liquid may be directly dissolved in the photopolymerizable monomer, oligomer, or liquid crystal material. If the ionic liquid has poor solubility in these materials, it may be dissolved in a small amount of solvent to obtain a solution, and then this solution may be mixed with the photopolymerizable monomer, oligomer, or liquid crystal material to dissolve the ionic liquid.

Examples of solvents include propylene carbonate, acetonitrile, γ-butyrolactone, ethylene carbonate, sulfolane, dioxolane, tetrahydrofuran, 2-methyltetrahydrofuran, dimethyl sulfoxide, 1,2-dimethoxyethane, 1,2-ethoxymethoxyethane, polyethylene glycol, alcohols, or mixed solvents thereof.

Examples of the ionic liquid include ethylmethylimidazolium tetracyanoborate (manufactured by Merck & Co., Ltd.), ethylmethylimidazolium bistrifluoromethanesulfonimide (manufactured by Kanto Chemical Co., Ltd.), ethylmethylimidazolium tripentafluoroethyl trifluorophosphate (manufactured by Merck & Co., Ltd.), ethylmethylimidazolium bis(fluorosulfonyl)imide (manufactured by Kanto Chemical Co., Ltd.), ethylmethylimidazolium diethylphosphate (manufactured by Tokyo Chemical Industry Co., Ltd.), butylmethylimidazolium hexafluorophosphate (manufactured by Tokyo Chemical Industry Co., Ltd.), ethylmethylimidazolium trifluoromethanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.), and ethylmethylimidazolium acetate (manufactured by Tokyo Chemical Industry Co., Ltd.). ), ethylmethylimidazolium tricyanomethanide (manufactured by Tokyo Chemical Industry Co., Ltd.), ethylmethylimidazolium dicyanamide (manufactured by Tokyo Chemical Industry Co., Ltd.), methyloctylimidazolium hexafluorophosphate (manufactured by Tokyo Chemical Industry Co., Ltd.), methylpropylpyrrolidinium bisfluorosulfonimide (manufactured by Kanto Chemical Industry Co., Ltd.), butylmethylimidazolium tetrafluoroborate (manufactured by Tokyo Chemical Industry Co., Ltd.), butylmethylimidazolium bis(trifluoromethanesulfonyl)imide (manufactured by Tokyo Chemical Industry Co., Ltd.), hexylmethylimidazolium bis(trifluoromethylsulfonyl)imide (manufactured by Kanto Chemical Industry Co., Ltd.), allylbutylimidazolium tetrafluoroborate (manufactured by Kanto Chemical Industry Co., Ltd.), etc. These may be used alone or in combination of two or more. Among these, ethylmethylimidazolium bisfluorosulfonimide, ethylmethylimidazolium tetracyanoborate, ethylmethylimidazolium bistrifluoromethanesulfonimide, ethylmethylimidazolium tripentafluoroethyl trifluorophosphate, and allylbutylimidazolium tetrafluoroborate are preferred, and ethylmethylimidazolium bisfluorosulfonimide is more preferred.

The content of the ionic liquid is preferably 55% by mass or more, and more preferably 60% by mass or more, based on the total amount of the electrolyte composition constituting the gel electrolyte. When the content of the ionic liquid is 55% by mass or more, it is possible to obtain a gel electrolyte that exhibits higher ionic conductivity while maintaining good processability. On the other hand, the upper limit of the content of the ionic liquid is not particularly limited, but from the viewpoint of improving processability, it is preferably 98% by mass or less, and more preferably 90% by mass or less.

(Binder resin)
The binder resin may be one or more selected from the group consisting of urethane (meth)acrylate, polymethyl (meth)acrylate, polyethyl (meth)acrylate, and poly(ethylene oxide)acrylate.

Among the above binder resins, polymers having urethane acrylate chains are particularly preferred. Polymers having urethane acrylate chains tend to exhibit a high elastic modulus even when they contain a large amount of ionic liquid, making it possible to obtain an electrolyte that exhibits a low amount of displacement in a steel ball indentation test.

The content of the polymer having a urethane acrylate chain is preferably 18% by mass to 40% by mass, and more preferably 20% by mass to 30% by mass, based on the total amount of the electrolyte composition constituting the gel electrolyte.
When the content of the polymer having a urethane acrylate chain is 18% by mass or more, a gel electrolyte that can withstand deformation during processing can be obtained, whereas when the content of the polymer having a urethane acrylate chain is 40% by mass or less, color development can be improved while maintaining good processability.

The molecular weight of the polymer having the urethane acrylate chain is preferably 5,000 to 30,000, and more preferably 8,000 to 20,000. By setting the molecular weight to the above lower limit or more, good coatability can be obtained when forming an electrolyte sheet. On the other hand, by setting the molecular weight to the above upper limit or less, good compatibility can be achieved.

Commercially available polymers having urethane acrylate chains include, for example, UXF4002 (Nippon Kayaku Co., Ltd.), UXT6100 (Nippon Kayaku Co., Ltd.), UX4101 (Nippon Kayaku Co., Ltd.), UX3204 (Nippon Kayaku Co., Ltd.), UX6101 (Nippon Kayaku Co., Ltd.), UX5000 (Nippon Kayaku Co., Ltd.), UN-350 (Negami Chemical Industrial Co., Ltd.), UN-5590 (Negami Chemical Industrial Co., Ltd.), UN-7700 (Negami Chemical Industrial Co., Ltd.), UN-9200A (Negami Chemical Industrial Co., Ltd.), UN-6303PR (Negami Chemical Industrial Co., Ltd.), UN-1255 (Negami Chemical Industrial Co., Ltd.), UN-6202PR (Negami Chemical Industrial Co., Ltd.), UN-6305 (Negami Chemical Industrial Co., Ltd.), UN-7600 (Negami Chemical Industrial Co., Ltd.), and UN6304 (Negami Chemical Industrial Co., Ltd.).

In addition, the above-mentioned binder resin is preferably a polymer having a polymethyl methacrylate (PMMA) chain, since the polymer having a PMMA chain is likely to exhibit tackiness even when it contains a large amount of ionic liquid, and it is possible to obtain a gel electrolyte that does not deform during transportation in the roll-to-roll electrolyte sheet production process.
Commercially available polymers having PMMA chains include, for example, MB-1 (manufactured by Toagosei Co., Ltd.), MB-1P (manufactured by Toagosei Co., Ltd.), and Hyperl M4501 (manufactured by Negami Chemical Industry Co., Ltd.).

The binder resin is preferably a crosslinked polymer having a polymethyl methacrylate (PMMA) chain. The crosslinked polymer having a PMMA chain can use a low molecular weight PMMA monomer having better compatibility than linear PMMA at the stage of the electrolyte composition, so that the content can be increased and tackiness can be more easily exhibited.
Examples of crosslinked polymers having PMMA include those obtained by crosslinking reactive oligomers or reactive polymers having PMMA chains.
The reactive oligomer having a PMMA chain is not particularly limited and can be appropriately selected depending on the purpose. For example, Macromonomer AA-6 (manufactured by Toagosei Co., Ltd.) can be mentioned.

The content of the crosslinked polymer having polymethyl methacrylate (PMMA) chains is preferably 1% by mass to 20% by mass, and more preferably 5% by mass to 10% by mass, based on the total amount of the electrolyte composition constituting the gel electrolyte.

<Other ingredients>
The other components are not particularly limited and can be appropriately selected depending on the purpose. For example, a polymerization initiator can be included.

The polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose. For example, a radical polymerization initiator can be used.
Examples of the radical polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator.

Examples of thermal polymerization initiators include azo compounds such as 2,2'-azobisisobutyronitrile, dimethyl-2,2'-azobisisobutyrate, 2,2'-azobis(2,4-dimethylvaleronitrile), and 2,2'-azobis[2-(2-imidazolin-2-yl)propane]; and organic peroxides such as 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and di(4-tert-butylcyclohexyl)peroxydicarbonate. These may be used alone or in combination of two or more.

Examples of photopolymerization initiators include ketal-based photopolymerization initiators such as 2,2-dimethoxy-1,2-diphenylethan-1-one; acetophenone-based photopolymerization initiators such as 1-hydroxycyclohexyl phenyl ketone, 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 4-phenoxydichloroacetophenone, and 4-(t-butyl)dichloroacetophenone; and benzoin ether-based photopolymerization initiators such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, and benzoin isobutyl ether. These may be used alone or in combination of two or more.

The content of the polymerization initiator is not particularly limited and can be appropriately selected depending on the purpose, but is preferably 0.001 parts by mass or more and 5 parts by mass or less, more preferably 0.01 parts by mass or more and 2 parts by mass or less, and particularly preferably 0.01 parts by mass or more and 1 part by mass or less, relative to 100 parts by mass of the total monomer components.

<Method of producing gel electrolyte>
When the electrolyte layer 4 is in a gel state, it can be prepared, for example, as follows.
First, a composition solution is prepared, and the prepared composition solution is sandwiched between a mold or a film and polymerized by a cast polymerization method or the like. The composition solution can be prepared by mixing an electrolyte solution obtained by mixing the ionic liquid or solid electrolyte with a solvent, a polymerizable material, a urethane acrylate monomer, and, if necessary, an acrylate monomer having a PEO chain, and, if necessary, an acrylate monomer having a PMMA chain in a desired ratio, and, if necessary, the polymerization initiator and other components can be mixed.
As another preparation method, a method of applying a composition solution before polymerization onto one electrochromic layer and polymerizing it by ultraviolet irradiation or heating can be used. Also, a method of placing the supports on which the electrochromic layers are formed facing each other while maintaining a gap of 5 μm to 150 μm, filling the composition solution, and then polymerizing it by ultraviolet irradiation or heating can be used.

[Electrochromic Layer]
The first electrochromic layer 3 and the second electrochromic layer 5 are provided on the upper and lower surfaces of the electrolyte layer 4, respectively, and are disposed so as to sandwich the electrolyte layer 4 therebetween. The first electrochromic layer 3 and the second electrochromic layer 5 are layers containing an electrochromic material.

The electrochromic material may be either an inorganic electrochromic compound or an organic electrochromic compound, or a conductive polymer known to exhibit electrochromism.
The first electrochromic layer 3 and the second electrochromic layer 5 can be made of any of these electrochromic materials. However, when one of them is made of an electrochromic material having oxidative coloring properties, it is preferable that the other is made of an electrochromic material having reductive coloring properties.
As the electrochromic material having oxidative coloring properties, a polymer obtained by polymerizing an oxidative coloring electrochromic composition containing a radical polymerizable compound is preferable, and an electrochromic composition containing a radical polymerizable compound having triarylamine is particularly preferable.

(First Electrochromic Layer)
The first electrochromic layer 3 contains, as a main material, a material that exhibits color through an oxidation reaction, and is thus a layer that is colored.

The average thickness of the first electrochromic layer 3 is not particularly limited, but is preferably about 0.1 μm or more and 30 μm or less, and more preferably about 0.4 μm or more and 10 μm or less.

The material that is contained as the main material in the first electrochromic layer 3 and that exhibits coloration through an oxidation reaction is not particularly limited, and examples thereof include a polymer obtained by polymerizing a composition that contains a radically polymerizable compound having a triarylamine, a bisacridan compound, a Prussian blue complex, and nickel oxide, and one or more of these can be used in combination.

Examples of polymers obtained by polymerizing a composition containing a radically polymerizable compound having a triarylamine include those described in JP-A-2016-45464 and JP-A-2020-138925.

Furthermore, an example of a Prussian blue type complex is a material made of Fe(III) ₄ [Fe(II)(CN) ₆ ] ₃ .

Among these, a polymer obtained by polymerizing a composition containing a radically polymerizable compound having triarylamine is particularly preferred, since it can be operated at a constant voltage, has excellent durability against repeated use, and produces an electrochromic element with high contrast.

The composition containing the radical polymerizable compound having a triarylamine may contain a radical polymerizable compound other than the radical polymerizable compound having a triarylamine, and the polymer obtained by polymerizing such a composition may be composed of a crosslinked product formed by crosslinking these radical polymerizable compounds.

(Second Electrochromic Layer)
The second electrochromic layer 5 contains, as a main material, an electrochromic material that changes from transparent to colored by a reduction reaction, and is thus a layer that is colored.

The average thickness of the second electrochromic layer 5 is not particularly limited, but is preferably about 0.2 μm to 5.0 μm, and more preferably about 1.0 μm to 4.0 μm. If the average thickness is less than 0.2 μm, depending on the type of electrochromic material, it may be difficult to obtain a desired color density. If it exceeds 5.0 μm, the manufacturing cost may increase, and depending on the type of electrochromic material, visibility may decrease due to coloring.

It is preferable that the second electrochromic layer 5 is made of an electrochromic material having the same color tone as the first electrochromic layer 3. This increases the maximum color density, thereby improving the contrast.

In contrast, when materials of different colors are used, color mixing becomes possible. In addition, by coloring the first electrode 2 and the second electrode 6 through oxidation and reduction reactions, the driving voltages in the electrochromic layer 3, electrolyte layer 4, and second electrochromic layer 5 can be effectively reduced, improving the repeated use durability of the electrochromic sheet 100.

The material contained as the main material in the second electrochromic layer 5 and which exhibits coloration through a reduction reaction is not particularly limited, and examples thereof include inorganic electrochromic compounds, organic electrochromic compounds, conductive polymers, etc., and one or a combination of two or more of these can be used.

Examples of inorganic electrochromic compounds include tungsten oxide, molybdenum oxide, iridium oxide, and titanium oxide, among which tungsten oxide is preferred. Tungsten oxide is preferably used because it has a low color development/discoloration potential due to its low reduction potential, and because it is an inorganic material, it has excellent durability.

Examples of organic electrochromic compounds include low molecular weight organic electrochromic compounds such as azobenzene, anthraquinone, diarylethene, dihydroprene, dipyridine, styryl, styrylspiropyran, spirooxazine, spirothiopyran, thioindigo, tetrathiafulvalene, terephthalic acid, triphenylmethane, triphenylamine, naphthopyran, viologen, pyrazoline, phenazine, phenylenediamine, phenoxazine, phenothiazine, phthalocyanine, fluoran, fulgide, benzopyran, and metallocene, among which viologen and dipyridine compounds are preferred. These compounds are preferably used because they have a low color development and fading potential and exhibit good color values.

Examples of viologen-based compounds include those described in Japanese Patent No. 3955641 and Japanese Patent Application Publication No. 2007-171781. Examples of dipyridine-based compounds include those described in Japanese Patent Application Publication No. 2007-171781 and Japanese Patent Application Publication No. 2008-116718.

Examples of conductive polymers include polypyrrole, polythiophene, polyaniline, and derivatives thereof.

[Support layer]
The first support layer 1 and the second support layer 7 have the function of supporting the first electrode 2, the first electrochromic layer 3, the electrolyte layer 4, the second electrochromic layer 5, the second electrode 6, and the sealing portion 8. They also serve as the outermost layers of the electrochromic sheet 100.

The first support layer 1 and the second support layer 7 constitute the outermost layers of the electrochromic sheet 100. In other words, at least the first electrochromic layer 3, the electrolyte layer 4, and the second electrochromic layer 5 are not exposed to the outside. Therefore, the first electrochromic layer 3, the electrolyte layer 4, and the second electrochromic layer 5 can be protected from moisture and oxygen gas from the outside, as well as physical impacts and friction.

The first support layer 1 and the second support layer 7 are not particularly limited as long as they are composed mainly of a transparent resin material, but it is preferable that they contain a transparent resin (base resin) with thermoplastic properties as the main material.

The transparent resin is not particularly limited, but examples thereof include transparent resins such as acrylic resins, polystyrene resins, polyethylene resins, polypropylene resins, polyester resins such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polycarbonate resins, polyamide resins, cycloolefin resins, vinyl chloride resins, polyacetal resins, and silicone resins. One or more of these resins may be used in combination. Among these, polycarbonate resins or polyamide resins are preferred, and polycarbonate resins are particularly preferred. Polycarbonate resins are rich in transparency (translucency) and mechanical strength such as rigidity, and also have high heat resistance, so that the use of polycarbonate resins as the transparent resin can improve the transparency, impact resistance, and heat resistance of the first support layer 1 and the second support layer 7.

Various resins can be used as the polycarbonate resin, but aromatic polycarbonate resins are preferred. Aromatic polycarbonate resins have aromatic rings in their main chains, which allows the first support layer 1 and second support layer 7 to have superior strength.

This aromatic polycarbonate resin is synthesized, for example, by an interfacial polycondensation reaction between bisphenol and phosgene, or an ester exchange reaction between bisphenol and diphenyl carbonate.

Examples of bisphenols include bisphenol A and bisphenol (modified bisphenol) which is the source of the repeating units of polycarbonate shown in the following formula (1A).

(In formula (1A), X is an alkyl group having 1 to 18 carbon atoms, an aromatic group, or a cyclic aliphatic group, Ra and Rb are each independently an alkyl group having 1 to 12 carbon atoms, m and n are each an integer of 0 to 4, and p is the number of repeating units.)

Specific examples of bisphenols that are the source of the repeating units of the polycarbonate represented by formula (1A) include 4,4'-(pentane-2,2-diyl)diphenol, 4,4'-(pentane-3,3-diyl)diphenol, 4,4'-(butane-2,2-diyl)diphenol, 1,1'-(cyclohexanediyl)diphenol, 2-cyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 2,3-biscyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 1,1'-bis(4-hydroxy-3-methylphenyl)cyclohexane, and 2,2'-bis(4-hydroxy-3-methylphenyl)propane. One or a combination of two or more of these can be used.

Among them, it is preferable that the polycarbonate resin mainly contains a bisphenol-type polycarbonate resin having a skeleton derived from bisphenol. By using such a bisphenol-type polycarbonate resin, the first support layer 1 and the second support layer 7 exhibit even greater strength.

Furthermore, the first support layer 1 and the second support layer 7 may be colorless or may be any color, such as red, blue, yellow, etc., as long as they are light-transmitting.

These colors can be selected by incorporating a dye or pigment into the first support layer 1 and the second support layer 7. Examples of such dyes include acid dyes, direct dyes, reactive dyes, and basic dyes, and one or more of these dyes can be used in combination.

Specific examples of dyes include, for example, C.I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. Acid Red 52, 80, 82, 249, 254, 289, C.I. Acid Blue 9, 45, 249, C.I. Acid Black 1, 2, 24, 94, C.I. Food Black 1, 2, C.I. Direct Yellow 1, 12, 24, 33, 50, 55, 58, 86, 132, 142, 144, 173, C.I. Direct Red 1, 4, 9, 80, 81, 225, 227, C.I. Direct Blue 1, 2, 15, 71, 86, 87, 98, 165, 199, 202, C.I. Direct Black 19, 38, 51, 71, 154, 168, 171, 195, C.I. Reactive Red 14, 32, 55, 79, 249, C.I. Reactive Black 3, 4, 35, etc.

The first support layer 1 and the second support layer 7 may contain various additives such as antioxidants, fillers, plasticizers, light stabilizers, ultraviolet absorbers, heat absorbers, and flame retardants in addition to the transparent resins, dyes, or pigments described above, as necessary.

The first support layer 1 and the second support layer 7 may be stretched or unstretched.

Furthermore, the refractive index of the first support layer 1 and the second support layer 7 at a wavelength of 589 nm is preferably 1.3 or more and 1.8 or less, and more preferably 1.4 or more and 1.65 or less. By setting the refractive index n1 of the first support layer 1 and the second support layer 7 within the above numerical range, the color development and fading function of the electrochromic sheet 100 can be easily visually recognized.

The average thickness of the first support layer 1 and the second support layer 7 is preferably set to 0.1 mm or more and 10.0 mm or less, and more preferably 0.3 mm or more and 5.0 mm or less.
By setting the average thickness of the first support layer 1 and the second support layer 7 within this range, it is possible to accurately suppress or prevent the electrochromic sheet 100 from warping while making the electrochromic sheet 100 thinner.

The first support layer and the second support layer 7 may be made of the same or different materials. In addition, both may be stretched, or only one may be unstretched.

The first support layer and the second support layer 7 may have the same refractive index or may have different refractive indices. The first support layer and the second support layer 7 may have the same thickness or may have different thicknesses.

[Sealing part]
The sealing portion 8 integrally covers the side surface of the electrolyte layer 4 and the side surfaces of the first electrochromic layer 3 and the second electrochromic layer 5, and is used to prevent moisture and oxygen gas from entering the electrochromic element 10 from the outside, and to adhere to the first support layer 1 and the second support layer 7 to prevent peeling from the electrochromic element 10. In addition, if the first electrochromic layer 3 and the second electrochromic layer 5 formed between the opposing first electrode 2 and second electrode 6 are misaligned, the color development quality during operation will decrease, so the sealing portion 8 is used to prevent this.

The average thickness (length in the stacking direction) of the sealing portion 8 is adjusted according to the average thickness of the electrochromic element 10, but is preferably set to, for example, about 20 μm or more and 100 μm or less, and more preferably about 40 μm or more and 80 μm or less.

(Sealing material)
The sealing material of the present embodiment is not particularly limited as long as it is an insulating material having transparency, but preferably contains a curable resin and inorganic particles.

Curable Resin The curable resin preferably has at least one of an ultraviolet-reactive functional group and a heat-reactive functional group, and more preferably has a (meth)acryloyl group and/or an epoxy group. Examples of the curable resin include (meth)acrylate and epoxy resin.

The (meth)acrylate is not particularly limited, and examples thereof include urethane (meth)acrylate having a urethane bond, and epoxy (meth)acrylate derived from a compound having a glycidyl group and (meth)acrylic acid.

The urethane (meth)acrylate is not particularly limited, and examples thereof include derivatives of diisocyanates such as isophorone diisocyanate and reactive compounds that undergo addition reactions with isocyanates such as acrylic acid and hydroxyethyl acrylate. These derivatives may be chain-extended with caprolactone, polyol, etc.

The epoxy (meth)acrylate is not particularly limited, and examples thereof include those obtained by reacting an epoxy compound with (meth)acrylic acid in the presence of a basic catalyst according to a conventional method. Examples include epoxy (meth)acrylates derived from an epoxy resin such as a bisphenol A type epoxy resin or propylene glycol diglycidyl ether and (meth)acrylic acid.

Other (meth)acrylates include, for example, one or more selected from methyl methacrylate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, glycidyl methacrylate, (poly)ethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, and glycerin dimethacrylate.

Examples of the epoxy resins include novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins, bisphenol type epoxy resins such as bisphenol A type epoxy resins and bisphenol F type epoxy resins, aromatic glycidylamine type epoxy resins such as N,N-diglycidylaniline, N,N-diglycidyltoluidine, diaminodiphenylmethane type glycidylamine, and aminophenol type glycidylamine, hydroquinone type epoxy resins, biphenyl type epoxy resins, stilbene type epoxy resins, triphenolmethane type epoxy resins, triphenolpropane type epoxy resins, and alkyl The epoxy resins include one or more selected from epoxy resins such as modified triphenolmethane type epoxy resins, triazine nucleus-containing epoxy resins, dicyclopentadiene modified phenol type epoxy resins, naphthol type epoxy resins, naphthalene type epoxy resins, phenol aralkyl type epoxy resins having a phenylene and/or biphenylene skeleton, and aralkyl type epoxy resins such as naphthol aralkyl type epoxy resins having a phenylene and/or biphenylene skeleton, and aliphatic epoxy resins such as vinylcyclohexene dioxide, dicyclopentadiene oxide, and alicyclic diepoxy adipides.

Also, as the curable resin, an epoxy/(meth)acrylic resin having at least one (meth)acrylic group and at least one epoxy group in one molecule may be used.

Inorganic Particles Examples of inorganic particles include one or more particles selected from silica, talc, glass beads, asbestos, gypsum, diatomaceous earth, smectite, bentonite, montmorillonite, sericite, activated clay, alumina, zinc oxide, iron oxide, magnesium oxide, tin oxide, titanium oxide, calcium carbonate, magnesium carbonate, magnesium hydroxide, aluminum hydroxide, aluminum nitride, silicon nitride, barium sulfate, calcium silicate, and the like.

The inorganic particles may have a hydrophobic surface. For example, the inorganic particles may be surface-treated by a known method using epoxysilane, aminosilane, (meth)acrylic silane, vinylsilane, methylchlorosilane, dimethylpolysiloxane, or the like. A mixture of inorganic particles that have been hydrophobically treated and those that have not may be used.

The content of inorganic particles is 1 to 80% by mass, preferably 3 to 70% by mass, and more preferably 20 to 60% by mass, based on the total amount of the sealing material.

Others The sealing material of the present embodiment may contain organic particles, a polymerization initiator, a heat curing agent, and the like in addition to the curable resin and inorganic particles.

The organic particles may be, for example, one or more selected from polyester fine particles, polyurethane fine particles, vinyl polymer fine particles, acrylic polymer fine particles, silicone fine particles, core-shell type rubber fine particles, etc.

Examples of the polymerization initiator include radical polymerization initiators and cationic polymerization initiators.

The radical polymerization initiator may be a photoradical polymerization initiator that generates radicals upon irradiation with light, or a thermal radical polymerization initiator that generates radicals upon heating.

Examples of the photoradical polymerization initiator include benzophenone-based compounds, acetophenone-based compounds, acylphosphine oxide-based compounds, titanocene-based compounds, oxime ester-based compounds, benzoin ether-based compounds, and thioxanthone.

The above-mentioned thermal radical polymerization initiator includes, for example, those made of azo compounds, organic peroxides, etc. Among them, polymeric azo initiators made of polymeric azo compounds are preferred.

As the cationic polymerization initiator, a photocationic polymerization initiator can be suitably used.
The photocationic polymerization initiator is not particularly limited as long as it generates a protonic acid or a Lewis acid upon irradiation with light, and may be either an ionic photoacid generating type or a nonionic photoacid generating type.
Examples of the photocationic polymerization initiator include onium salts such as aromatic diazonium salts, aromatic halonium salts, and aromatic sulfonium salts; and organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes.

The content of the polymerization initiator is preferably 0.1 to 30 parts by weight, and more preferably 1 to 10 parts by weight, based on 100 parts by weight of the curable resin.
When the content of the polymerization initiator is equal to or more than the lower limit, the sealing material has better curability, whereas when the content of the polymerization initiator is equal to or less than the upper limit, the sealing material has better storage stability.

The heat curing agent is used to react and crosslink the heat-reactive functional groups in the curable resin by heating, and has the role of improving the adhesiveness and moisture resistance of the curable resin composition after curing.
Examples of the heat curing agent include organic acid hydrazides, imidazole derivatives, amine compounds, polyhydric phenol compounds, acid anhydrides, etc. Among these, solid organic acid hydrazides are preferably used.

The content of the heat curing agent is preferably 0.1 to 50 parts by weight, and more preferably 1 to 30 parts by weight, based on 100 parts by weight of the curable resin.
When the content of the polymerization initiator is equal to or more than the lower limit, the sealing material has better curability, whereas when the content of the polymerization initiator is equal to or less than the upper limit, the sealing material has better coatability.

Additives such as silane coupling agents, light blocking agents, reactive diluents, spacers, curing accelerators, defoamers, leveling agents, polymerization inhibitors, and other coupling agents may also be included as necessary.

(Method of manufacturing sealing material)
An example of a method for producing the sealing material of the present embodiment is a method in which a curable resin, inorganic particles, and additives such as a polymerization initiator and/or a heat curing agent or a silane coupling agent, which are added as necessary, are mixed using a mixer.
Examples of the mixer include a homodisper, a homomixer, a universal mixer, a planetary mixer, a kneader, a three-roll mill, and a planetary mixer.

[electrode]
The first electrode 2 and the second electrode 6 are electrodes that supply electrons between the first electrode 2 and the second electrode 6, or receive electrons from between the first electrode 2 and the second electrode 6, when a positive voltage or a negative voltage is applied to the first electrochromic layer 3, the electrolyte layer 4, and the second electrochromic layer 5, respectively.
The first electrode 2 is provided on the surface of the first electrochromic layer 3 opposite to the electrolyte layer 4. The second electrode 6 is provided on the surface of the second electrochromic layer 5 opposite to the electrolyte layer 4.

The constituent material of the first electrode 2 and the second electrode 6 is not particularly limited as long as it is a transparent conductive material, and examples thereof include oxides such as ITO (indium tin oxide), FTO (F-doped tin oxide), ATO (antimony tin oxide), IZO (indium zinc oxide), In ₂ O ₃ , SnO ₂ , Sb-containing SnO ₂ , and Al-containing ZnO, Au, Pt, Ag, Cu, and alloys containing these, and one or more of these may be used in combination.

Methods for producing the first electrode 2 and the second electrode 6 include, for example, vacuum deposition, sputtering, and ion plating. In addition, as long as the materials for the first electrode 2 and the second electrode 6 can be applied, various printing methods such as spin coating, casting, microgravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, slit coating, capillary coating, spray coating, nozzle coating, gravure printing, screen printing, flexographic printing, offset printing, reverse printing, and inkjet printing can be used.

The average thickness of the first electrode 2 and the second electrode 6 is adjusted so as to obtain the electrical resistance value required for the redox reaction of the first electrochromic layer 3 and the second electrochromic layer 5. For example, when ITO is used as the constituent material of the first electrode 2 and the second electrode 6, the average thickness is preferably set independently to about 50 nm or more and 200 nm or less, more preferably about 100 nm or more and 150 nm or less.

In addition, an intermediate layer, such as an insulating porous layer or a protective layer, may be provided between each layer between the first electrode 2 and the second electrode 6.

The total thickness of the electrochromic sheet 100 of this embodiment is not particularly limited, but is preferably 0.3 mm or more and 10.0 mm or less, and more preferably 0.5 mm or more and 5.0 mm or less.
By making the total thickness of the electrochromic sheet 100 equal to or greater than the above-mentioned lower limit, strength can be maintained, while by making the layer thickness equal to or less than the above-mentioned upper limit, the electrochromic sheet 100 can be easily processed, such as by cutting or bending.

Each layer of the electrochromic sheet 100 may be replaced with any other layer that can provide a similar function, or the electrochromic sheet 100 may further include other layers.

[Action and Effect]
By having the above-described configuration, the electrochromic sheet 100 can, for example, cause the electrochromic element 10 to develop a predetermined color by applying a positive voltage between the first electrode 2 and the second electrode 6, while the electrochromic element 10 can be decolorized and made transparent by applying a negative voltage between the first electrode 2 and the second electrode 6.

<Method of manufacturing electrochromic sheet>
The method for producing an electrochromic sheet according to the present embodiment is not limited to the case where there is one electrochromic layer, but can also be applied to the case where there are multiple electrochromic layers.
An example of a method for producing the electrochromic sheet 100 will now be described.

The method for manufacturing the electrochromic sheet 100 includes the following steps.
A step of forming a first electrode 2 on a first support 1 and laminating a first electrochromic layer 3 on the first electrode 2;
forming a second electrode 6 on a second support 7 and forming a second electrochromic layer 5 on the second electrode 6;
applying a sealing material onto the first electrode 2 so as to surround the outer edge of the first electrochromic layer 3, or applying a sealing material onto the second electrode 6 so as to surround the outer edge of the second electrochromic layer 5;
a step of preparing an electrolyte layer 4, and bonding a first support 1 and a second support 2 together with a first electrochromic layer 3 and a second electrochromic layer 5 facing each other with the electrolyte layer 4 interposed therebetween;
a step of hardening the sealing material to form a sealing portion 8;
having
In the lamination step, the sealing material is spread out, so that the first electrochromic layer 3 and the second electrochromic layer 5 are covered with the sealing material.
In this way, the electrochromic sheet 100 is obtained.

<Electrochromic Device>
The electrochromic device of this embodiment has the electrochromic sheet 100 described above, and may further have other means as necessary.
The other means are not particularly limited and can be appropriately selected depending on the application. Examples of the other means include a power source, a fixing means, and a control means.
Examples of electrochromic devices include eyewear, photochromic glasses, binoculars, opera glasses, bicycle goggles, watches, electronic paper, electronic albums, and electronic billboards.

The above describes the embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

Next, the present invention will be described in detail using examples, but the content of the present invention is not limited to the examples.

(1) Preparation of Gel Electrolyte The following materials were prepared.
Binder resin 1: urethane acrylate (product name: UXF4002, manufactured by Nippon Kayaku Co., Ltd.)
Binder resin 2: Crosslinked polymer having polymethyl methacrylate (PMMA) chains (product name: AA-6, manufactured by Toa Gosei Co., Ltd.)
Ionic liquid 1: (EMIMFSI, ethylmethylimidazolium bisfluorosulfonimide, Kanto Chemical Co., Ltd.)

Example 1
A solution prepared by mixing binder resin 1, binder resin 2, and ionic liquid 1 in the ratios shown in Table 1 and further mixing 0.5 mass % of a photopolymerization initiator (irgacure 184, manufactured by Nippon Kayaku Co., Ltd.) with respect to the total amount of binder resins 1 and 2 was applied to the surface of a release-treated PET film (NP75C, manufactured by PANAC Corporation), and the resulting solution was bonded to a release-treated PET film (NP75A, manufactured by PANAC Corporation) and cured with ultraviolet (UV) light to produce a gel electrolyte.

<Comparative Example 1>
A gel electrolyte was prepared in the same manner as in Example 1, except that the contents of the binder resins 1 and 2 and the ionic liquid 1 were changed to the ratios shown in Table 1.

(2) Preparation of Electrochromic Sheet An electrochromic sheet as shown in FIG. 1 was prepared by the following procedure.
--Formation of the first electrode--
As a first support, a polycarbonate resin substrate (Polycaace, deflection temperature under load 140° C., manufactured by Sumitomo Bakelite Co., Ltd.) having a thickness of 0.5 mm was prepared.
An ITO film was formed on the first support by sputtering to a thickness of about 100 nm to form a first electrode.
3 g of titanium oxide (ST-21, manufactured by Ishihara Sangyo Kaisha), 0.2 g of acetylacetone, 0.3 g of a surfactant (polyoxyethylene octylphenyl ether, manufactured by Wako Pure Chemical Industries, Ltd.) were treated in a bead mill together with 5.5 g of water and 1.0 g of ethanol for 12 hours.
To the resulting dispersion was added 1.2 g of polyethylene glycol (#20,000, manufactured by NOF Corporation) to prepare a paste.
The obtained paste was applied onto the first electrode by screen printing to a thickness of 2 μm, dried at 80° C., and then subjected to UV ozone treatment at 90° C. for 20 minutes to form an electron transport layer made of a porous titanium oxide particle film.

--Formation of the first electrochromic layer--
Next, a 2,2,3,3-tetrafluoropropanol solution containing 1.5 mass % of a reductively coloring electrochromic compound I represented by the following chemical formula was applied by spin coating, and then annealed at 80° C. for 10 minutes to support (adsorb) the compound on the porous titanium oxide particle film, thereby forming a first electrochromic layer.

--Formation of the second electrode--
A polycarbonate resin substrate having the same shape and thickness as the first support was prepared as a second support. An ITO film was formed on the second support by sputtering to a thickness of about 100 nm to form a second electrode.

- Formation of second electrochromic layer -
On the ITO film, which is the second electrode, polyethylene glycol diacrylate (PEG400DA, manufactured by Nippon Kayaku Co., Ltd.) and a photoinitiator (IRGACURE 184, manufactured by BASF) were applied.
A solution was prepared by mixing a radical polymerizable compound II having a triarylamine represented by the following formula as an oxidative coloring electrochromic material and 2-butanone in a mass ratio of 57:3:140:800. The prepared solution was then applied onto an ITO glass substrate by spin coating.

（式中、Ｍｅはメチル基を示す）

(In the formula, Me represents a methyl group.)

Next, in a nitrogen atmosphere, a patterned second electrochromic layer containing the compound represented by the radical polymerizable compound II above was selectively formed on the second electrode by UV curing via a quartz substrate with a Cr layer pattern, with a thickness of 1.2 μm.

- Bonding process -
The release film was peeled off from each of the gel electrolytes prepared in (1) above, and the gel electrolyte was attached to the surface of the first electrochromic layer.
Next, the prepared sealing material (epoxy acrylate resin ("Photolec S-WF17" manufactured by Sekisui Material Solutions Co., Ltd.) was applied by a dispenser method so as to surround the periphery of the side surface of the first electrochromic layer.
Thereafter, the second electrochromic layer of the second support was aligned with the surface of the gel electrolyte and bonded to each other, and the sealing material was spread to cover the sides of the first electrochromic layer and the second electrochromic layer with the sealing material. The sealing material was then irradiated with 3 J/ ^cm2 of ultraviolet light (pre-curing), and heat-cured at 100°C for 1 hour (main curing) to cure the sealing material and form a sealing portion, thereby producing an electrochromic sheet.

(3) Measurement and Evaluation Next, the following measurements and evaluations were carried out on the obtained electrochromic sheet of Example 1. The results are shown in Table 1.

Measurement of deformation amount The deformation amount was measured according to the following steps i and ii. The displacement-load curve, with the horizontal axis representing the displacement amount (mm) and the vertical axis representing the load (N), is shown in FIG.
Step i: Using the electrochromic sheet, a test piece (60 x 80 mm; elliptical) was prepared with the electrolyte layer at the center and the sealing portion as the outer edge, and both ends of the test piece were chucked with chucking portions, and the center of the test piece was pressed with 30 N for 30 seconds. The difference in depth between the center of the test piece before pressing and the center of the test piece after pressing was recorded as the variation (mm).
Step ii: Using the electrochromic sheet, a test piece (60 x 80 mm; elliptical) was prepared with the electrolyte layer at the center and the sealing portion as the outer edge, and both ends of the test piece were chucked with the chucking portions, and the center of the test piece was pressed with 50 N for 30 seconds. The difference in depth between the center of the test piece before pressing and the center of the test piece after pressing was recorded as the variation (mm).

In both procedures, the hard ball indentation test was performed using a Tensilon RTF-2430 (manufactured by Orientec Co., Ltd.) with a hard ball diameter of 30 mm, a loading speed of 0.1 mm/min (crosshead speed), a creep load of 30 N or 50 N, a creep time of 30 seconds, and at room temperature.

(4) Evaluation The processability of the obtained electrochromic sheet was evaluated. The results are shown in Table 2.
- Processability The electrochromic sheet was subjected to cutting processing on the periphery while the center of the electrochromic sheet was chucked. The presence or absence of chuck marks was then evaluated according to the following criteria. The absence of chuck marks indicates that the electrochromic sheet has good processability.
[Evaluation criteria]
〇: No zipper marks are visible ×: Zipper marks are visible

REFERENCE SIGNS LIST 1 First support layer 2 Second electrode 3 First electrochromic layer 4 Electrolyte layer 5 Second electrochromic layer 6 Second electrode 7 Second support layer 8 Sealing portion 10 Electrochromic element 100 Electrochromic sheet

Claims (12)

A support layer;
an electrolyte layer provided on the support layer;
an electrochromic layer provided on at least one surface of the electrolyte layer;
a sealing portion provided so as to cover at least a side surface of the electrolyte layer;
An electrochromic sheet comprising:
The electrochromic sheet has a deformation of 0.01 mm to 0.09 mm as measured by the following procedure i.
Step i: Using the electrochromic sheet, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer as the center and the sealing portion as the outer edge, both ends of the test piece are chucked with chucking portions, and the center of the test piece is pressed with 30 N for 30 seconds, and the difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is the deformation amount (mm). 2. The electrochromic sheet according to claim 1,
An electrochromic sheet having a deformation of 0.10 mm or less as measured by the following procedure ii.
Step ii: Using the electrochromic sheet, a test piece (maximum length 20 mm or more) is prepared with the electrolyte layer as the center and the sealing portion as the outer edge, both ends of the test piece are chucked with chucking portions, and the center of the test piece is pressed with 50 N for 30 seconds, and the difference in depth between the center of the test piece before pressing and the center of the test piece after pressing is the deformation amount (mm). 2. The electrochromic sheet according to claim 1,
In step i, an electrochromic sheet having no yield point. 3. The electrochromic sheet according to claim 2,
In step ii), an electrochromic sheet having no yield point. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet, wherein the electrolyte layer is a solid or a gel. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet, wherein the electrolyte layer includes a binder resin. 7. The electrochromic sheet according to claim 6,
The electrochromic sheet, wherein the binder resin comprises one or more resins selected from the group consisting of urethane (meth)acrylate, polymethyl (meth)acrylate, polyethyl (meth)acrylate, and poly(ethylene oxide)acrylate. 3. The electrochromic sheet according to claim 1 or 2,
An electrochromic sheet, the electrochromic layers being provided on the upper and lower surfaces of the electrolyte layer of the electrochromic sheet. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet, wherein the sealing portion is formed using a sealing material containing a curable resin. 10. The electrochromic sheet according to claim 9,
The electrochromic sheet, wherein the curable resin has at least one selected from an ultraviolet-reactive functional group and a heat-reactive functional group. 3. The electrochromic sheet according to claim 1 or 2,
The electrochromic sheet further comprises an electrode layer between the support layer and the electrochromic layer. An electrochromic device using the electrochromic sheet according to claim 1 or 2.

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