JP2011085622A - Electrolyte and electrochemical device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrolyte having excellent repetition durability, and an electrochemical device using it, especially a display element. <P>SOLUTION: In the electrolyte containing a nonaqueous solvent and inorganic particles, the content rate of a compound containing three or more OH groups or COOH groups bonded to carbon atoms is not less than 10 mass ppm and not more than 1.0 mass% with respect to the whole electrolyte mass. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a novel electrolytic solution, and an electrochemical device using the electrolytic solution, in particular, a display element.

  In recent years, the use of electrochemical devices using an electrolytic solution using a non-aqueous solvent for various purposes has progressed. As such an electrochemical device, a Li ion secondary battery, a large capacity capacitor, and the like are known.

  Among electrochemical devices, development of electrochemical display elements for browsing electronic information is particularly active. As a means for browsing such electronic information, conventional liquid crystal displays and CRTs, and in recent years, light-emitting types such as organic EL displays are mainly used. However, when the electronic information is document information, it is necessary to watch the browsing means for a relatively long time, and these actions are hardly human-friendly means. In general, it has been pointed out that the disadvantages of light-emitting displays are flickering eyes, inconvenient to carry, restricted reading posture, need to focus on the static screen, and increase power consumption when reading for a long time. .

  As a display means to compensate for these drawbacks, a reflection type display using so-called "memory" that uses external light and does not consume power for image retention is known. However, it has sufficient performance for the following reasons. It is hard to say that it has.

  That is, a method using a polarizing plate such as a reflective liquid crystal has a low reflectance of about 40%, and thus has a difficulty in white display. In addition, since the polymer dispersed liquid crystal requires a high voltage and uses a difference in refractive index between organic substances, the contrast of an obtained image is not sufficient. In addition, the polymer network type liquid crystal has problems such as a high voltage and a complicated TFT circuit required to improve the memory performance. In addition, a display element based on electrophoresis requires a high voltage of 10 V or more, and there is a concern about durability due to electrophoretic particle aggregation.

  As a display method for solving the disadvantages of each of the above-mentioned methods, an electrodeposition method (hereinafter referred to as “ED method”) and an electrochromic method (hereinafter referred to as “EC method”) using dissolution precipitation of a metal or a metal salt. For example)). The ED method can be driven at a low voltage of 3 V or less, has advantages such as a simple cell configuration, excellent black-white contrast and black quality, and various methods have been disclosed (for example, Patent Document 1). 2).

  Further, the EC method can be driven at a low voltage of 3 V or less, has an advantage of simple cell configuration and color display, and various methods are disclosed. In particular, the EC method has an advantage that a desired color can be developed and erased by designing an organic material, and full color display is possible (for example, see Patent Document 3).

  Although development of the above-described ED type and EC type display elements has been actively conducted, there is a problem that the repeated durability is still insufficient in view of commercialization.

U.S. Pat. No. 4,240,716 Japanese Patent Laid-Open No. 2005-266652 JP 2003-270670 A

  The present invention has been made in view of the above-described problems and circumstances, and a problem to be solved is to provide an electrolytic solution excellent in repeated durability and an electrochemical device using the electrolytic solution, particularly a display element.

  The above object of the present invention can be achieved by the following configuration.

  1. An electrolytic solution containing a non-aqueous solvent and inorganic fine particles, which has a compound containing three or more OH groups or COOH groups bonded to carbon atoms, and the content of the compound is 10 with respect to the total electrolytic solution mass. Electrolyte characterized by being not less than ppm by mass and not more than 1.0% by mass.

  2. 2. The electrolyte solution according to 1 above, wherein the content of the compound is 10 mass ppm or more and 0.5 mass% or less with respect to the total electrolyte solution mass.

  3. 3. The electrolytic solution according to 1 or 2 above, which contains inorganic fine particles treated with the compound.

  4). 4. The electrolyte solution according to any one of items 1 to 3, wherein a moisture content of the electrolyte solution is 200 ppm or less.

  5. 4. The electrolyte solution according to any one of items 1 to 3, wherein the water content of the electrolyte solution is 50 ppm or less.

  6). 6. An electrochemical device using the electrolytic solution according to any one of 1 to 5 above.

  7. 7. The electrochemical device as described in 6 above, wherein the electrochemical device is an electrochromic display element or an electrodeposition display element.

  By means of the present invention, an electrolytic solution excellent in repeated durability and an electrochemical device, particularly a display element, which can be driven at a low voltage and excellent in repeated durability can be provided by using the electrolytic solution. Furthermore, it has also been clarified that storage stability is improved when a display element using the electrolytic solution of the present invention is prepared.

  The electrolytic solution of the present invention contains a non-aqueous solvent and inorganic fine particles, and further contains 10% by mass of the compound containing three or more OH groups or COOH groups bonded to carbon atoms with respect to the total mass of the electrolytic solution. It is characterized by being not less than ppm and not more than 1.0 mass%. This feature is a technical feature common to the present invention.

  Moreover, the electrochemical device excellent in repetition durability was able to be provided by using such electrolyte solution. Furthermore, when the electrolytic solution of the present invention is applied to an EC type or ED type display element, it has become clear that, in addition to the improvement of repeated durability, the storage stability is improved.

  It is known to those skilled in the art that removal of impurities is effective for improving durability in an electrochemical device. However, it is still unclear what impurities are present in the electrolyte solution containing the nonaqueous solvent and inorganic fine particles, which is a form of the present invention, and how much the performance is improved by removing the impurities.

  In order to solve such a problem, the present inventors have conducted intensive research and have not yet clarified the mechanism and reaction, but a compound containing three or more OH groups or COOH groups bonded to a carbon atom. By reducing the content to below a certain content, it has succeeded in greatly improving repeated durability. Furthermore, the inventors have found that storage stability can be improved by containing a very small amount of a compound containing three or more OH groups or COOH groups bonded to carbon atoms, and the present invention has been achieved.

  Hereinafter, the electrolytic solution of the present invention will be described.

  The electrolytic solution of the present invention is a non-aqueous solvent containing inorganic fine particles, and the content of the compound containing three or more OH groups or COOH groups bonded to carbon atoms is 10 mass ppm with respect to the total mass of the electrolytic solution. It is characterized by being suppressed to 1.0 mass% or less, preferably 10 mass ppm or more and 0.5 mass% or less, more preferably 10 mass ppm or more to 0.1 mass% or less.

  Examples of the non-aqueous solvent (organic solvent) in the electrolytic solution according to the present invention include propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, γ-butyl lactone, sulfolane, dimethyl sulfoxide, butyronitrile, Propionitrile, acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2-propanol, 1-propanol, acetic anhydride, ethyl acetate, ethyl propionate, dimethoxyethane, diethoxyfuran, tetrahydrofuran , Ethylene glycol, diethylene glycol, triethylene glycol monobutyl ether, tricresyl phosphate, 2 ethylhexyl phosphate, Examples include ruphthalate and dioctyl sebacate, more preferably propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, and γ-butyl lactone, and further propylene carbonate, ethylene carbonate, and ethyl. More preferred are methyl carbonate and γ-butyl lactone.

Further, the inorganic fine particles shown in the present invention are not particularly limited, but are particularly preferably white pigments. Examples of such white pigments include titanium dioxide (anatase type or rutile type), barium sulfate, calcium carbonate, oxidation Examples include aluminum, zinc oxide, magnesium oxide and zinc hydroxide, magnesium hydroxide, magnesium phosphate, magnesium hydrogen phosphate, alkaline earth metal salts, talc, kaolin, zeolite, acidic clay, and glass. In such inorganic fine particles, there is a concern that dispersibility in a solvent may be reduced due to the formation of fine particles, and various dispersants are generally present together. In the present invention, among the white particles, titanium dioxide is preferably used, and in particular, inorganic oxides such as Al ₂ O ₃ , AlO (OH), SiO _2, etc., which are subjected to surface treatment of titanium dioxide or organic matter treatment. Titanium dioxide is more preferably used.

  Inorganic fine particles are known to adsorb various substances on the surface thereof. As a method for removing and washing the adsorbed material, water, an organic solvent or a mixed solvent thereof is mixed, and the adsorbed material is dissolved in the solvent and removed by filtration or centrifugation. A method of adding and removing a surfactant or the like is preferably used. It is also possible to use a method of heating the inorganic fine particles at a high temperature of 600 ° C. or higher to decompose the adsorbed material, or a method of decomposing the adsorbed material with an acid or base. In the washing step, it is more preferable to perform surface treatment with an organic substance such as an inorganic oxide or alkoxysilane in order to suppress re-adsorption of the adsorbed substance and maintain dispersibility.

  In addition, compounds containing three or more OH groups or COOH groups bonded to carbon atoms according to the present invention are generally collectively referred to as polyhydric alcohol compounds, polyhydric carboxylic acids, polyhydric hydroxycarboxylic acids, and the like. It is used as an agent and polymer raw material. Among these, examples of the polyhydric alcohol compound containing three or more OH groups include glycerin, trimethylolethane, trimethylolpropane, erythritol, pentaerythritol, sorbitol, sucrose, quadrol, and polymerization adducts thereof (for example, ethylene oxide (EO). ), Polyether polyols obtained by modification with cyclic ether compounds such as propylene oxide (PO), butylene oxide, and tetrahydrofuran, trisphenol PA, phenol novolac, cresol novolac, polyhydroxy acrylate) and the like.

  Examples of the polyvalent carboxylic acid containing 3 or more COOH groups include trimellitic acid, trimesic acid, pyromellitic acid, cyclohexanetricarboxylic acid, naphthalenetricarboxylic acid, naphthalenetricarboxylic acid, butanetricarboxylic acid, hexanetricarboxylic acid, 1,3 -Dicarboxyl-2-methyl-2-methylenecarboxypropane, octanetetracarboxylic acid, benzophenonetetracarboxylic acid, acid anhydrides thereof, polyacrylic acid, and polyacrylic acid copolymers. Furthermore, the hydroxycarboxylic acid of the present invention is a compound having a hydroxy group (—OH) and a carboxy group (—COOH) in the same molecule. Examples of the polyvalent hydroxycarboxylic acid containing three or more OH groups or COOH groups bonded to carbon atoms include 2,2-dimethylolacetic acid, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2 -Dimethylolpentanoic acid, 2,2-dimethylolhexanoic acid, 2,2-dimethylolheptanoic acid, 2,2-dimethyloloctanoic acid, 2,3-dihydroxybutanoic acid (tartaric acid), 3-methyl-2, 3-dihydroxybutanoic acid, 3-ethyl-2,3-dihydroxybutanoic acid, 3-propyl-2,3-dihydroxybutanoic acid, 3-butyl-2,3-dihydroxybutanoic acid, 3-pentyl-2,3- Dihydroxybutanoic acid, 3-hexyl-2,3-dihydroxybutanoic acid, 2,3-dimethyl-2,3-dihydroxybutanoic acid, 2-methyl-3- Til-2,3-dihydroxybutanoic acid, 2-methyl-3-propyl-2,3-dihydroxybutanoic acid, 2-methyl-3-butyl-2,3-dihydroxybutanoic acid, 2-methyl-3-pentyl- 2,3-dihydroxybutanoic acid, 2-methyl-3-hexyl-2,3-dihydroxybutanoic acid, 2,3-diethyl-2,3-dihydroxybutanoic acid, 2-ethyl-3-propyl-2,3- Dihydroxybutanoic acid, 2-ethyl-3-butyl-2,3-dihydroxybutanoic acid, 2-ethyl-3-pentyl-2,3-dihydroxybutanoic acid, 2-ethyl-3-hexyl-2,3-dihydroxybutane Acid, 2,3-dipropyl-2,3-dihydroxybutanoic acid, 2-propyl-3-butyl-2,3-dihydroxybutanoic acid, 2-propyl-3-pentyl-2 3-dihydroxybutanoic acid, 2-propyl-3-hexyl-2,3-dihydroxybutanoic acid, 2,3-dibutyl-2,3-dihydroxybutanoic acid, 2-butyl-3-pentyl-2,3-dihydroxybutane Acid, 2-butyl-3-hexyl-2,3-dihydroxybutanoic acid, 2,3-dipentyl-2,3-dihydroxybutanoic acid, 2-pentyl-3-hexyl-2,3-dihydroxybutanoic acid, 2, Examples include 3-dihexyl-2,3-dihydroxybutanoic acid.

  A compound containing three or more OH groups or COOH groups bonded to a carbon atom can be detected and identified by a known analytical method such as nuclear magnetic resonance spectrum, gas chromatography, or liquid chromatography.

  Further, the molecular weight of the compound containing three or more OH groups or COOH groups bonded to the carbon atom is not particularly limited, but the molecular weight is preferably 50 to 20000, more preferably the molecular weight is 75 to 5000, More preferably, the molecular weight is 100-2000.

  The water content of the electrolytic solution of the present invention is preferably 500 ppm or less, more preferably 200 ppm or less, and even more preferably 50 ppm or less. The water content of the electrolytic solution can be measured by a Karl Fischer trace water content measurement method or gas chromatography. In the electrolytic solution of the present invention, the compound containing three or more OH groups or COOH groups bonded to carbon atoms is within the range of 10 mass ppm to 1.0 mass%, and the moisture content is below the above level. By suppressing it, it is possible to remarkably improve the repeated durability by a synergistic effect.

  In addition, the electrolytic solution of the present invention preferably contains 1 to 10% of a polyether compound, and more preferably 2 to 6% of a polyether compound. The polyether compound shown here is a compound having a plurality of ether structures in the molecule. Examples of such a polyether compound include polyethylene glycol, polypropylene glycol, and some or all of these oxygen atoms substituted with sulfur atoms. Polyethylene sulfide, polypropylene sulfide, and end-modified polyethylene glycol whose terminal groups are treated with acetic anhydride or the like, and the total number of OH groups or COOH groups bonded to carbon atoms in the molecule is 2 or less. Features. Moreover, it is preferable that the polyether compound of this invention has sufficient solubility with respect to electrolyte solution, It is preferable that it is 500-100000 as molecular weight, More preferably, it is 2000-50000, Furthermore, it is 2000-20000. It is more preferable.

  The electrolytic solution of the present invention is used in an electrochemical device utilizing an electrochemical reaction, and as such an electrochemical device, a primary battery, a secondary battery, a capacitor, a capacitor, a solar cell, a fuel cell, a smart window, A display element etc. are mentioned, Especially application to a display element is preferable. In particular, the electrolytic solution of the present invention is preferably applied to an EC display element and an ED display element as such a display element.

  Hereinafter, the display element using the electrolytic solution of the present invention will be described in detail.

<Basic structure of display element>
In the display element of the present invention, a transparent electrode such as an ITO electrode is provided on an electrode which is an electrode (display side electrode) close to the display unit among at least one pair of opposed electrodes, and an electrode (distant from the other display unit) The counter electrode is provided with a conductive electrode. Between the display-side electrode and the counter electrode, there is an electrolyte layer containing the organic solvent, inorganic fine particles and EC dye or ED compound according to the present invention, and positive and negative voltages are applied between at least one pair of facing electrodes. By applying, coloring and decoloring can be switched reversibly. The electrolyte layer in the display element of the present invention can further contain various additives.

〔substrate〕
The substrate that can be used in the present invention is preferably a transparent substrate. Examples of such a transparent substrate include polyester (for example, polyethylene terephthalate), polyimide, polymethyl methacrylate, polystyrene, polypropylene, polyethylene, and polyamide. Nylon, polyvinyl chloride, polyvinylidene chloride, polycarbonate, polyether sulfone, silicon resin, polyacetal resin, fluororesin, cellulose derivative, polyolefin and other polymer films, plate substrates, glass substrates, and the like are preferably used. The transparent substrate used in the present invention refers to a substrate having a transmittance for visible light of at least 50%.

  Further, as the counter substrate, for example, an opaque substrate such as an inorganic substrate such as a metal substrate or a ceramic substrate can be used.

〔electrode〕
(Display side transparent electrode)
Of the at least one pair of opposing electrodes, the electrode located on the display side (display side electrode) is preferably a transparent electrode.

  The transparent electrode is not particularly limited as long as it is transparent and conducts electricity. For example, Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, Zinc Oxide, Platinum, Gold, Silver, Rhodium, Copper, Examples thereof include chromium, carbon, aluminum, silicon, amorphous silicon, and BSO (Bismuth Silicon Oxide).

  In addition, polythiophene, polypyrrole, polyaniline, polyacetylene, polyparaphenylene, polyselenophenylene, etc., and their modifying compounds can be used alone or in combination.

  As an electrode located on the display side (display side electrode), Indium Tin Oxide (ITO: Indium Tin Oxide), Indium Zinc Oxide (IZO: Indium Zinc Oxide), Fluorine Doped Tin Oxide (FTO), Indium Oxide, An electrode made of a transparent conductive oxide such as zinc oxide is preferable.

  The surface resistance value is preferably 100Ω / □ or less, and more preferably 10Ω / □ or less. The thickness of the transparent electrode is not particularly limited, but is generally 0.1 to 20 μm.

(Transparent porous electrode)
As one embodiment of the transparent electrode, a nanoporous electrode having a nanoporous structure can be provided on the transparent electrode. This nanoporous electrode is substantially transparent when a display element is formed, and can carry an electroactive substance such as an electrochromic dye.

  The nanoporous structure as used in the present invention refers to a state in which an infinite number of nanometer-sized pores exist in a layer, and the ionic species contained in the electrolyte can move within the nanoporous structure. .

  As a method for forming such a nanoporous electrode, a dispersion containing fine particles constituting the nanoporous electrode is formed in layers by an ink jet method, a screen printing method, a blade coating method, etc., and then heated at a predetermined temperature. A method of making porous by drying, baking, a method of making nanoporous by anodizing or photoelectrochemical etching after forming an electrode layer by sputtering, CVD, atmospheric pressure plasma, etc. Is mentioned. Also, the sol-gel method, Adv. Mater. It can also be formed by the method described in 2006, 18, 2980-2983.

The main components of the fine particles constituting the nanoporous electrode are metals such as Cu, Al, Pt, Ag, Pd and Au, metal oxides such as ITO, SnO ₂ , TiO ₂ and ZnO, carbon nanotubes, glassy carbon, and diamond. It can be selected from carbon electrodes such as like carbon and nitrogen-containing carbon, and is preferably selected from metal oxides such as ITO, SnO ₂ , TiO ₂ , and ZnO.

  In order for the nanoporous electrode to have transparency, it is preferable to use fine particles having an average particle diameter of about 5 nm to 10 μm. As the shape of the fine particles, those having an arbitrary shape such as an indefinite shape, a needle shape, and a spherical shape can be used.

  The film thickness of the nanoporous electrode is preferably in the range of 0.1 to 10 μm, more preferably in the range of 0.25 to 5 μm.

(Counter electrode)
Of the at least one pair of opposing electrodes, an electrode positioned on the opposite side of the display side and the electrolyte solution (hereinafter referred to as a counter electrode) is preferably a transparent electrode.

  The counter electrode can be used without particular limitation as long as it conducts electricity.

  As the constituent material of the counter electrode, in addition to the same material as the transparent electrode, metals such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, bismuth and their alloys, carbon, etc. have no transparency. A material can also be preferably used.

(Porous carbon electrode)
In the present invention, a porous carbon electrode can also be used as the counter electrode. Porous carbon electrodes that can be adsorbed and supported include graphite, non-graphitizable carbon, graphitizable carbon, composite carbon, and carbon compounds obtained by doping carbon with boron, nitrogen, phosphorus, etc. Can be mentioned. Examples of the shape of the carbon particles include mesophase microspheres and fibrous graphite. Mesophase spherules can be obtained by firing coal tar pitch or the like at 350 to 500 ° C., and further classifying these spherules and graphitizing by high-temperature firing can provide a good porous carbon electrode. In addition, fibrous graphite can be obtained from pitch-based, PAN-based, and vapor-grown fibers.

(Auxiliary electrode = grid electrode)
An auxiliary electrode can be attached to at least one of the at least one pair of opposing electrodes according to the present invention.

  The auxiliary electrode is preferably made of a material having a lower electrical resistance than the main electrode portion. For example, metals such as platinum, gold, silver, copper, aluminum, zinc, nickel, titanium, and bismuth and alloys thereof can be preferably used.

  The auxiliary electrode can be installed either between the main electrode portion and the substrate, or on the surface of the main electrode portion opposite to the substrate. In any case, it is only necessary that the auxiliary electrode is electrically connected to the main electrode portion.

  There are no particular restrictions on the arrangement pattern of the auxiliary electrodes. It can be appropriately formed according to the required performance, such as linear, mesh, or circular. When the main electrode part is divided into a plurality of parts, the divided electrode parts may be connected to each other. However, in the case where the main electrode portion is a transparent electrode provided on the substrate on the display side, the auxiliary electrode is required to be provided with a shape and frequency that do not impair the visibility of the display element.

  As a method of forming the auxiliary electrode, a known method can be used. For example, a patterning method by photolithography, a printing method, an ink jet method, electrolytic plating or electroless plating, or a method of forming a pattern by exposing and developing using a silver salt photosensitive material may be used.

  The line width and line spacing of the auxiliary electrode pattern may be arbitrary values, but the line width needs to be increased in order to increase the conductivity. On the other hand, when an auxiliary electrode is attached to the transparent electrode, from the viewpoint of visibility, the area coverage of the auxiliary electrode viewed from the display element observation side is preferably 30% or less, and more preferably 10% or less.

  Thus, from the viewpoint of transmittance and conductivity, the line width of the auxiliary electrode is preferably 1 μm or more and 100 μm or less, and the line interval is preferably 50 μm to 1000 μm.

(Method of forming electrode)
A known method can be used to form the transparent electrode and the metal auxiliary electrode. For example, a method of depositing a mask on a substrate by a sputtering method or the like, a method of patterning by a photolithography method after forming the entire surface, and the like can be given.

  Electrodes can also be formed by electrolytic plating, electroless plating, printing methods, and ink jet methods.

  After forming an electrode pattern including a catalyst layer having a monomer polymerization ability on a substrate using an inkjet method, a monomer component that is polymerized by the catalyst and becomes a conductive polymer layer after polymerization is added, It is also possible to form a metal electrode pattern by polymerizing and further performing metal plating such as silver on the conductive polymer layer, and the process is greatly reduced because no photoresist or mask pattern is used. It can be simplified.

  When the electrode material is formed by a coating method, for example, a known method such as a dipping method, a spinner method, a spray method, a roll coater method, a flexographic printing method, a screen printing method, or the like can be used.

  Among the ink jet methods, the following electrostatic ink jet method can continuously print a high-viscosity liquid with high accuracy, and is preferably used for forming the transparent electrode and the metal auxiliary electrode according to the present invention. The viscosity of the ink is preferably 30 mPa · s or more, and more preferably 100 mPa · s or more.

<Electrostatic inkjet method>
In the display element of the present invention, at least one of the transparent electrode of the composite electrode and the metal auxiliary electrode has a liquid discharge head having a nozzle with an internal diameter of 30 μm or less for discharging a charged liquid, and supplies a solution into the nozzle. It is one of the preferable embodiments that the liquid discharge device is provided with a supply unit that performs the discharge and a discharge voltage application unit that applies a discharge voltage to the solution in the nozzle. Further, it is preferable that the solution in the nozzle is formed by using a discharge device provided with a convex meniscus forming means for forming a state where the solution rises from the nozzle tip.

  In addition, it comprises operation control means for controlling application of drive voltage for driving the convex meniscus forming means and application of discharge voltage by the discharge voltage application means, and this operation control means applies application of the discharge voltage by the discharge voltage application means. It is also preferable to use a liquid ejection apparatus having a first ejection control unit that applies a driving voltage to the convex meniscus forming means when ejecting liquid droplets.

  In addition, an operation control unit that controls driving of the convex meniscus forming unit and voltage application by the discharge voltage applying unit is provided, and the operation control unit includes an operation for raising the solution by the convex meniscus forming unit, and application of the discharge voltage. A liquid discharge device having a second discharge control unit that synchronizes the liquid, and the operation control means includes a liquid level at the tip of the nozzle after the swell operation of the solution and the application of the discharge voltage. It is also a preferred form to use a liquid ejection apparatus having a liquid level stabilization control unit that performs operation control for drawing in the inside.

  By producing an electrode pattern using such an electrostatic inkjet, it is advantageous that an electrode having excellent on-demand characteristics, little waste material, and excellent dimensional accuracy can be obtained.

(Electronic insulation layer)
In the display element of the present invention, an electrical insulating layer can be provided.

  The electronic insulating layer applicable to the present invention may be a layer having both ionic conductivity and electronic insulating properties. For example, a solid electrolyte solution film in which a polymer or salt having a polar group is formed into a film, electronic insulating Porous membranes with high properties and quasi-solid electrolyte membranes carrying electrolytes in the voids, polymer porous membranes with voids, porous materials of inorganic materials with low relative dielectric constant such as silicon-containing compounds, etc. Can be mentioned.

  As a method for forming a porous film, a sintering method (fusion method) (using fine pores formed between particles by adding polymer fine particles or inorganic particles to a binder or the like and partially fusing them), an extraction method ( After forming a constituent layer with a solvent-soluble organic substance or inorganic substance and a binder that does not dissolve in the solvent, the organic substance or inorganic substance is dissolved with the solvent to obtain pores), and the polymer is heated or degassed Known forming methods such as a foaming method in which foaming is performed, a phase change method in which a mixture of polymers is phase-separated by operating a good solvent and a poor solvent, and a radiation irradiation method in which pores are formed by radiating various types of radiation Can be used. Specifically, JP-A-10-30181, JP-A-2003-107626, JP-B-7-95403, JP-A-2635715, JP-A-2894523, JP-A-2987474, JP-A-3066426, and JP-A-3464513. No. 3,483,464, No. 3535942, No. 30622203, and the like.

<Electrolytic solution layer composition (electrolytic solution)>
[Organic solvent (non-aqueous solvent)]
Examples of the organic solvent that can be used in the electrolyte layer composition according to the present invention include propylene carbonate, ethylene carbonate, ethyl methyl carbonate, diethyl carbonate, dimethyl carbonate, butylene carbonate, γ-butyl lactone, sulfolane, dimethyl sulfoxide, butyronitrile, Propionitrile, acetonitrile, acetylacetone, 4-methyl-2-pentanone, 2-butanol, 1-butanol, 2-propanol, 1-propanol, acetic anhydride, ethyl acetate, ethyl propionate, dimethoxyethane, diethoxyfuran, tetrahydrofuran , Ethylene glycol, diethylene glycol, triethylene glycol monobutyl ether, tricresyl phosphate, 2-ethylhexyl phosphate Dioctyl phthalate, and di-octyl sebacate and the like.

[Ionic liquid]
The ionic liquid is also referred to as a room temperature molten salt, and is a salt having a melting point of 100 ° C. or lower, and is included in the category of an organic solvent (nonaqueous solvent) in the present invention. This salt is composed of the same number of cations and anions, and there are many substances having a melting point below room temperature depending on the molecular structure, and these are in a liquid state at room temperature without adding any solvent. An ionic liquid has a strong characteristic that it has a strong electrostatic interaction and thus has almost no vapor pressure, and does not evaporate even at high temperatures. The ionic liquid used in the present invention may be any substance that is generally studied and reported. In particular, an organic ionic liquid has a molecular structure that exhibits a liquid in a wide temperature range including room temperature.

The ionic liquid used in the present invention is represented by the formula Q ⁺ A ⁻ and is 20 to 100 ° C., preferably 20 to 80 ° C., more preferably 20 to 60 ° C., further preferably 20 to 40 ° C., particularly 20 ° C. The viscosity (25 ° C.) is not particularly limited as long as it is a melt at room temperature, but is preferably 1 to 200 mPa · s. Further, the cation component represented by Q ⁺ in the formula is preferably an onium cation, more preferably an ammonium cation, an imidazolium cation, a pyridinium cation, a sulfonium cation, and a phosphonium cation.

The above ionic liquid will be specifically described in detail. As Q ⁺ in the above formula, R ₁ R ₂ R ₃ R ₄ N ⁺ , R ₁ R ₂ R ₃ S ⁺ , R ₁ R ₂ R ₃ R ₄ P ⁺ , R ₁ R ₂ N ⁺ = CR ₃ R ₄ , R ₁ R ₂ P ⁺ = CR ₃ R ₄ [where R ₁ to R ₄ are, independently of one another, hydrogen, saturated or unsaturated carbon C 1 -C 12 alkyl group, a cycloalkyl group having 3 to 8 carbon atoms, an aryl group or an aralkyl group having a carbon number of 7-11 having 6 to 10 carbon _{atoms, R 5 -X- (R 6 -Y-} ) - n (Wherein R ₅ represents an alkyl group having 4 or less carbon atoms, R ₆ represents an alkylene group having 4 or less carbon atoms, X and Y represent an oxygen atom or a sulfur atom, and n represents an integer of 0 to 10). And the group may be substituted] ammonium selected from the group consisting of Phosphonium _{^{ion, R 1 R 2 N + =}} CR 3 -R 7 -R 3 C = N + R 1 R 2, R 1 R 2 S + -R 7 -S + R 1 R 2, R 1 R 2 P + ^{_{= CR 3 -R 7 -R 3 C}} = P + R 1 R 2 ( _wherein, R 1, _{R 2} and _{R 3} are the same as defined above, and _{R 7} is 1 to carbon atoms A quaternary ammonium and / or phosphonium ion selected from the group consisting of 6 alkylene or phenylene groups, which may have a substituent, and nitrogen represented by the following general formula: Examples thereof include nitrogen ions containing 1, 2 or 3 atoms selected from sulfur and phosphorus atoms, ammonium ions derived from sulfur and phosphorus atom-containing heterocycles, sulfonium ions, phosphonium ions, and the like.

Wherein R ₁ and R ₂ are as defined above, and Z is an atom capable of constituting a 4-10 membered ring containing N ⁺ , N ⁺ = C, S ⁺ , P ⁺ or P ⁺ = C And the constituent atoms may have a substituent.

Specific examples of the above R ₁ to R ₄ include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, Linear or branched alkyl groups such as decyl, cycloalkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, unsubstituted or halogen atoms (F, Cl, Br, I), hydroxyl groups, Lower alkoxy group (methoxy, ethoxy, propoxy, butoxy), carboxyl group, acetyl group, propanoyl group, thiol group, lower alkylthio group (methylthio, ethylthio, propylthio, butylthio), amino group, lower alkylamino group, di-lower alkylamino Substitutions such as groups Phenyl having one to three, naphthyl, tolyl, aryl group xylyl, and aralkyl groups such as benzyl and the like. Further, specific examples of _{R 5} include methyl, ethyl, n- propyl, isopropyl, n- butyl, isobutyl, sec- butyl, and alkyl group such as tert- butyl group, methylene as _{R 6} And alkylene groups such as ethylene, propylene and butylene groups. Furthermore, specific examples of R ₇ include alkylene groups such as methylene, ethylene, propylene, and butylene, and phenylene groups such as phenylene.

Further, A in the formula ^- Examples of the counter anion represented by, hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, fluorosulfonate salts, tetrafluoroborate, nitrate, alkyl sulfonate Represents a fluorinated alkyl sulfonate or a hydrogen sulfate.

  Furthermore, WO95 / 18456, JP-A-8-259543, JP-A-2001-243959, Electrochemistry 65, 11, 923 (1997), EP-716288, J. Org. Electrochem. Soc. , Vol. 143, no. 10, 3099 (1996), Inorg. Chem. The pyridinium salts, imidazolium salts, triazolium salts and the like described in 1996, 35, 1168 to 1178 can be selected and used in a timely manner according to the present invention.

[Electrochromic compound (hereinafter referred to as EC compound or EC dye)]
The EC compound is not particularly limited as long as it exhibits an action of color development or decoloration by at least one of an electrochemical oxidation reaction and a reduction reaction, and can be appropriately selected according to the purpose. EC compounds include tungsten oxide, iridium oxide, nickel oxide, cobalt oxide, vanadium oxide, molybdenum oxide, titanium oxide, indium oxide, chromium oxide, manganese oxide, Prussian blue, indium nitride, tin nitride, zirconium nitride chloride, etc. In addition to compounds, organometallic complexes, conductive polymer compounds, and organic dyes are known.

  Examples of the organometallic complex exhibiting EC characteristics include metal-bipyridyl complexes, metal phenanthroline complexes, metal-phthalocyanine complexes, rare earth diphthalocyanine complexes, and ferrocene dyes.

  Examples of the conductive polymer compound exhibiting EC characteristics include polypyrrole, polythiophene, polyisothianaphthene, polyaniline, polyphenylenediamine, polybenzidine, polyaminophenol, polyvinylcarbazole, polycarbazole, and derivatives thereof.

  In addition, a polymer material composed of a bisterpyridine derivative and a metal ion as described in, for example, JP-A-2007-112957 also exhibits EC characteristics.

  Organic dyes exhibiting EC characteristics include pyridinium compounds such as viologen, azine dyes such as phenothiazine, styryl dyes, anthraquinone dyes, pyrazoline dyes, fluorane dyes, donor / acceptor compounds (for example, tetracyanoquinodis Methane, tetrathiafulvalene) and the like. In addition, compounds known as redox indicators and pH indicators can be used.

EC compounds are classified into the following three classes when classified in terms of color change.
Class 1: EC compounds that change from one specific color to another by redox.
Class 2: EC compounds that are substantially colorless in the oxidized state and exhibit a specific colored state that is the reduced state.
Class 3: EC compounds that are substantially colorless in the reduced state and exhibit a particular colored state that is the oxidized state.

In the display element of the present invention, the class 1 to class 3 EC compounds can be appropriately selected depending on the purpose and application.
[Class 1 EC compounds]
Class 1 EC compounds are EC compounds that change from a specific color to another color by oxidation-reduction, and are compounds that can display two or more colors in their possible oxidation states.

As compounds classified into class 1, for example, V ₂ O ₅ changes from orange to green by changing from an oxidized state to a reduced state, and similarly Rh ₂ O ₃ changes from yellow to dark green.

Many of the organometallic complexes are classified as class 1, and ruthenium (II) bipyridine complexes, such as tris (5,5'-dicarboxylethyl-2,2'-bipyridine) ruthenium complexes, are between +2 and -4 valences, The color changes from orange to purple, blue, green blue, brown, red rust and red. Many of the rare earth diphthalocyanines also exhibit such multicolor characteristics. For example, in the case of lutetium diphthalocyanine, the color gradually changes from purple to blue, green, and red-orange according to oxidation. Many of the conductive polymers are also classified as class 1. For example, polythiophene changes from blue to red by changing from an oxidized state to a reduced state, and polypyrrole changes from brown to yellow. In addition, polyaniline or the like exhibits multi-color characteristics and changes from an amber color of an oxidation state to blue, green, and light yellow in order. EC compounds classified as class 1 have a merit that multicolor display is possible with a single compound, but on the other hand, they have a drawback that a state that can be said to be substantially colorless cannot be made.
[Class 2 EC compounds]
Class 2 EC compounds are compounds that are colorless or extremely light in an oxidized state and exhibit a specific colored state that is a reduced state.

Examples of the inorganic compounds classified as class 2 include the following compounds, each of which shows the color shown in parentheses in the reduced state. WO ₃ (blue), MnO ₃ (blue), Nb ₂ O ₅ (blue), TiO ₂ (blue) and the like.

  As an organometallic complex classified into class 2, for example, a tris (vasophenanthroline) iron (II) complex can be mentioned, which shows red in a reduced state.

  Examples of organic dyes classified as class 2 include compounds described in JP-A Nos. 62-71934 and 2006-71765, such as dimethyl terephthalate (red) and diethyl 4,4′-biphenylcarboxylate. (Yellow), 1,4-diacetylbenzene (cyan), or tetrazolium salt compounds described in JP-A-1-230026, JP-T-2000-504964, and the like.

  The most representative dyes classified into class 2 are pyridinium compounds such as viologen. Viologen compounds have the advantages of vivid display and color variations by changing the substituents, etc., so they are the most actively studied among organic dyes. ing. Color development is based on organic radicals generated by reduction.

  Examples of pyridinium-based compounds such as viologen include compounds described in the following patents, starting with JP 2000-506629 A.

  JP-A-5-70455, JP-A-5-170738, JP-A-2000-235198, JP-A-2001-114769, JP-A-2001-172293, JP-A-2001-181292, JP-A-2001-181293, Table 2001-510590, JP-A-2004-101729, JP-A-2006-154683, JP-T-2006-519222, JP-A-2007-31708, 2007-171817, 2007-219271, 2007-219272, JP-T JP 2007-279659, JP 2007-279570, JP 2007-279571, JP 2007-279572, and the like.

  Examples of pyridinium compounds such as viologen that can be used in the present invention are shown below, but are not limited thereto.

[Class 3 EC compounds]
Class 3 EC compounds are compounds that are colorless or extremely pale in the reduced state and exhibit a specific colored state that is an oxidized state.

  Examples of inorganic compounds classified as class 3 include iridium oxide (dark blue), Prussian blue (blue), and the like (each of which shows the color shown in parentheses in the oxidized state).

  There are few examples of conductive polymers classified into class 3, but for example, phenyl ether compounds described in JP-A-6-263846 can be mentioned.

  Many dyes are known as class 3 dyes, styryl dyes, azine dyes such as phenazine, phenothiazine, phenoxazine, and acridine, azole dyes such as imidazole, oxazole, and thiazole are preferable. .

  Examples of styryl dyes, azine dyes, and azole dyes that can be used in the present invention are shown below, but are not limited thereto.

  In a preferred embodiment of the present invention, a metal salt (electrodeposition compound) reversibly dissolved and precipitated by an electrochemical oxidation-reduction reaction is used in combination with the EC dye, and black display, white display, and coloring other than black Performs multi-color display of three or more colors. In this case, since the metal salt is reduced to give a black display, the EC dye is preferably a class 3 EC compound that develops color by oxidation, and particularly an azole series in terms of color development diversity, low driving voltage, memory properties, and the like. A dye is preferred. In the present invention, the most preferred dye is a compound represented by the following general formula (L).

  Hereinafter, the electrochromic compound represented by the general formula (L) according to the present invention will be described.

In the general formula (L), Rl ₁ represents a substituted or unsubstituted aryl group, and Rl ₂ and Rl ₃ each represent a hydrogen atom or a substituent. X represents> N—Rl ₄ , an oxygen atom or a sulfur atom, and Rl ₄ represents a hydrogen atom or a substituent. When Rl ₁ represents an aryl group having a substituent, the substituent is not particularly limited, and examples thereof include the following substituents.

  Alkyl groups (eg, methyl, ethyl, propyl, isopropyl, tert-butyl, pentyl, hexyl, etc.), cycloalkyl groups (eg, cyclohexyl, cyclopentyl, etc.), alkenyl groups, cycloalkenyl groups , Alkynyl groups (for example, propargyl group), glycidyl groups, acrylate groups, methacrylate groups, aromatic groups (for example, phenyl group, naphthyl group, anthracenyl group, etc.), heterocyclic groups (for example, pyridyl group, thiazolyl group, oxazolyl group) Group, imidazolyl group, furyl group, pyrrolyl group, pyrazinyl group, pyrimidinyl group, pyridazinyl group, selenazolyl group, sriphoranyl group, piperidinyl group, pyrazolyl group, tetrazolyl group, etc.), alkoxy group (for example, methoxy group, ethoxy group, propyloxy) Group, pliers Oxy group, cyclopentyloxy group, hexyloxy group, cyclohexyloxy group, etc.), aryloxy group (eg, phenoxy group, etc.), alkoxycarbonyl group (eg, methyloxycarbonyl group, ethyloxycarbonyl group, butyloxycarbonyl group, etc.) , Aryloxycarbonyl group (for example, phenyloxycarbonyl group), sulfonamide group (for example, methanesulfonamide group, ethanesulfonamide group, butanesulfonamide group, hexanesulfonamide group, cyclohexanesulfonamide group, benzenesulfonamide group ), Sulfamoyl group (for example, aminosulfonyl group, methylaminosulfonyl group, dimethylaminosulfonyl group, butylaminosulfonyl group, hexylaminosulfonyl group, cyclohexylamino) Sulfonyl group, phenylaminosulfonyl group, 2-pyridylaminosulfonyl group, etc.), urethane group (for example, methylureido group, ethylureido group, pentylureido group, cyclohexylureido group, phenylureido group, 2-pyridylureido group, etc.), acyl Groups (eg, acetyl, propionyl, butanoyl, hexanoyl, cyclohexanoyl, benzoyl, pyridinoyl, etc.), carbamoyl groups (eg, aminocarbonyl, methylaminocarbonyl, dimethylaminocarbonyl, propylamino) Carbonyl group, pentylaminocarbonyl group, cyclohexylaminocarbonyl group, phenylaminocarbonyl group, 2-pyridylaminocarbonyl group, etc.), acylamino group (for example, acetylamino group, benzoyla) Mino group, methylureido group, etc.), sulfonyl group (eg, methylsulfonyl group, ethylsulfonyl group, butylsulfonyl group, cyclohexylsulfonyl group, phenylsulfonyl group, 2-pyridylsulfonyl group, etc.), amino group (eg, amino group, Ethylamino group, dimethylamino group, butylamino group, cyclopentylamino group, anilino group, 2-pyridylamino group, etc.), halogen atom (eg chlorine atom, bromine atom, iodine atom etc.), cyano group, nitro group, sulfo group Carboxyl group, hydroxyl group, phosphono group (for example, phosphonoethyl group, phosphonopropyl group, phosphonooxyethyl group) and the like. Further, these groups may be further substituted with these groups.

Rl ₁ is preferably a substituted or unsubstituted phenyl group, more preferably a substituted or unsubstituted 2-hydroxyphenyl group or 4-hydroxyphenyl group.

Rl _2, Rl is not particularly limited as substituent represented by _3, etc. substituents exemplified as a substituent on the aryl group of the Rl ₁ can be mentioned. Rl ₂ and Rl ₃ are preferably an alkyl group, a cycloalkyl group, an aromatic group, or a heterocyclic group, which may have a substituent. Rl ₂ and Rl ₃ may be connected to each other to form a ring structure. As a combination of Rl ₂ and Rl ₃ , both of them may be a phenyl group or a heterocyclic group which may have a substituent, or one of them may be a phenyl group or a heterocyclic group which may have a substituent. Yes, the other is a combination of alkyl groups which may have a substituent.

X is preferably a> N-Rl _4. Rl ₄ is preferably a hydrogen atom, an alkyl group, an aromatic group, a heterocyclic group or an acyl group, more preferably a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an aryl group having 5 to 10 carbon atoms, or acyl. It is a group.

In the display element of the present invention, it is preferable that the compound represented by the general formula (L) according to the present invention has a group that chemically or physically adsorbs on the electrode surface. The chemical adsorption according to the present invention is a relatively strong adsorption state due to a chemical bond with the electrode surface, and the physical adsorption according to the present invention is a relatively strong van der Waals force acting between the electrode surface and the adsorbed substance. It is weakly adsorbed. The adsorptive group according to the present invention is preferably a chemisorbable group. Examples of the adsorptive group to be chemisorbed include —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and -Si (OR) ₃ (R represents an alkyl group) is preferable.

  Among the azole dyes represented by the general formula (L), an imidazole dye represented by the following general formula (L2) is particularly preferable.

In the general formula (L2), Rl ₂₁ and Rl ₂₂ represent an aliphatic group, an aliphatic oxy group, an acylamino group, a carbamoyl group, an acyl group, a sulfonamide group, and a sulfamoyl group, and Rl ₂₃ represents an aromatic group or an aromatic group. Rl ₂₄ represents a hydrogen atom, an aliphatic group, an aromatic group or an aromatic heterocyclic group, and Rl ₂₅ represents a hydrogen atom, an aliphatic group, an aromatic group or an acyl group.

These groups represented by Rl ₂₁ to Rl ₂₅ may be further substituted with an arbitrary substituent. However, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has —COOH, —P═O (OH) ₂ , —OP═O (OH) ₂ and —Si (OR) ₃ (R Represents an alkyl group).

The group represented by the general formulas Rl ₂₁ and Rl ₂₂ is preferably an alkyl group (particularly a branched alkyl group), a cycloalkyl group, an alkyloxy group, or a cycloalkyloxy group. Rl ₂₃ is preferably a substituted or unsubstituted phenyl group, a 5-membered or 6-membered heterocyclic group (for example, thienyl group, furyl group, pyrrolyl group, pyridyl group, etc.). Rl ₂₄ is preferably a substituted or unsubstituted phenyl group, a 5-membered or 6-membered heterocyclic group, or an alkyl group. Rl ₂₅ is particularly preferably a hydrogen atom or an aryl group.

When fixing the general formula (L2) on the electrode, at least one of the groups represented by Rl ₂₁ to Rl ₂₅ has a partial structure of —P═O (OH) ₂ , —Si (OR) ₃ (R Preferably represents an alkyl group), and particularly preferably has —Si (OR) ₃ (R represents an alkyl group) as a partial structure of the group represented by Rl ₂₃ or Rl ₂₄ .

  Specific examples of the EC dye represented by the general formula (L2) and specific examples of the EC dye contained in the general formula (L) that do not correspond to the general formula (L2) are shown below. The invention is not limited to these exemplified compounds.

[Electrodeposition compounds (ED compounds)]
The ED compound applicable to the display element of the present invention is a metal salt compound, and a metal species that can be dissolved and deposited by driving the counter electrode on at least one electrode on the counter electrode. As long as it contains a salt, any compound may be used. Preferred metal species are silver, bismuth, copper, nickel, iron, chromium, zinc, etc., preferably silver and bismuth, and particularly preferred is silver.

[Silver salt compound]
As the silver salt compound that can be used in the present invention, silver or a compound containing silver in the chemical structure, for example, silver oxide, silver sulfide, metallic silver, silver colloidal particles, silver halide, silver complex compound, silver ion There are no particular restrictions on the phase state species such as the solid state, the solubilized state in liquid, the gas state, and the like, and the charged state species such as neutral, anionic, and cationic.

  In the display element of the present invention, silver iodide, silver chloride, silver bromide, silver oxide, silver sulfide, silver citrate, silver acetate, silver behenate, silver p-toluenesulfonate, silver trifluoromethanesulfonate, mercapto It is preferable to use a known silver salt compound such as a silver salt with an acid or a silver complex with iminodiacetic acid. Among these, it is more preferable to use, as the silver salt, a compound that does not have a nitrogen atom having coordination properties with halogen, carboxylic acid, or silver, and for example, silver p-toluenesulfonate is particularly preferable.

  The metal ion concentration contained in the electrolyte layer of the present invention is preferably 0.2 mol / kg ≦ [Metal] ≦ 2.0 mol / kg. If the metal ion concentration is 0.2 mol / kg or more, a silver solution having a sufficient concentration can be obtained, and a desired driving speed can be obtained. If the metal ion concentration is 2 mol / kg or less, precipitation is prevented, and storage at low temperature is possible. The stability of the electrolyte layer is improved.

[Halogen ion, metal ion concentration ratio]
In the display element of the present invention, the molar concentration of halogen ions contained in the electrolyte layer or halogen atoms of halogen molecules is [X] (mol / kg), and the molar concentration of metal ions contained in the electrolyte layer is [Metal]. ] (Mol / kg), it is preferable to satisfy the conditions defined by the following formula (1).

Formula (1): 0 ≦ [X] / [Metal] ≦ 0.01
The halogen atom as used in the field of this invention means an iodine atom, a chlorine atom, a bromine atom, and a fluorine atom. [X] / [Metal] is larger than 0.01, when the oxidation-reduction reaction of the metal, X ^- _{X 2} is generated from, _{X 2} is dissolved metal precipitated readily cross oxide and metal deposited Therefore, the molar concentration of halogen atoms is preferably as low as possible relative to the molar concentration of metallic silver. In the case of adding halogen ions, the halogen species preferably have a total molar concentration of [I] <[Br] <[Cl] <[F] from the viewpoint of improving memory properties.

[Silver salt solvent]
In the present invention, a silver salt solvent can be used to promote dissolution and precipitation of metal salts (particularly silver salts). The silver salt solvent may be any compound that can solubilize silver in the electrolytic solution. For example, silver or a compound containing silver coexisting with a compound containing a chemical structural species that interacts with silver, such as a coordinate bond with silver or a weak supply bond with silver. It is common to use a means for converting to a solubilizate. As the chemical species, halogen atoms, mercapto groups, carboxyl groups, imino groups and the like are known, but in the present invention, compounds containing thioether groups and mercaptoazoles are useful as silver solvents, and It is characterized by low influence on coexisting compounds and high solubility in solvents.

  As such a silver salt solvent, it is particularly preferable to contain at least one compound represented by the following general formula (G1) or general formula (G2).

[Compound represented by General Formula (G1) or General Formula (G2)]
General formula (G1)
_{Rg 11} -S-Rg ₁₂
[Wherein Rg ₁₁ and Rg ₁₂ each represents a substituted or unsubstituted hydrocarbon group. These hydrocarbon groups may contain one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and halogen atoms, and Rg ₁₁ and Rg ₁₂ may be linked to each other to form a cyclic structure. ]

[Wherein, M represents a hydrogen atom, a metal atom or quaternary ammonium. Z represents an atomic group necessary for constituting a nitrogen-containing heterocyclic ring. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed. ]
In the general formula (G1), Rg ₁₁ and Rg ₁₂ each represent a substituted or unsubstituted hydrocarbon group, which includes an aromatic straight chain group or a branched group. In addition, these hydrocarbon groups may contain one or more nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, Rg ₁₁ and Rg ₁₂ may be linked to each other to form a cyclic structure, and further thioether A structure having a large number of may be used. When taking the structure which has many thioethers, the coupling group between thioether bonds is not particularly limited, but is preferably an aromatic ring or an alkylene group, more preferably an alkylene group. In this case, the alkylene group is preferably a propylene group or an ethylene group, more preferably an ethylene group. In other words, it preferably has an ethylene dithioether structure in the molecule. Moreover, the alkylene group in this case may have a branch in the middle.

  Examples of groups that can be substituted for the hydrocarbon group include amino groups, guanidino groups, quaternary ammonium groups, hydroxyl groups, halogen compounds, carboxylic acid groups, carboxylate groups, amide groups, sulfinic acid groups, sulfonic acid groups, and sulfates. Groups, phosphonic acid groups, phosphate groups, nitro groups, cyano groups and the like.

  Specific examples of the compound represented by the general formula (G1) are shown below, but the present invention is not limited to these exemplified compounds.

G1-1: CH ₃ SCH ₂ CH ₂ OH
G1-2: HOCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-3: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-4: HOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OH
G1-5: HOCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ OH
_{G1-6: HOCH 2 CH 2 OCH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 OCH 2 CH 2 OH
G1-7: H ₃ CSCH ₂ CH ₂ COOH
G1-8: HOOCCH ₂ SCH ₂ COOH
G1-9: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-10: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ COOH
G1-11: HOOCCH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ COOH
G1-12: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-13: HOOCCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH (OH) CH (OH) CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ COOH
G1-14: H ₃ CSCH ₂ CH ₂ CH ₂ NH ₂
G1-15: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-16: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-17: H ₃ CSCH ₂ CH ₂ CH (NH ₂ ) COOH
G1-18: H ₂ NCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ NH _{2
G1-19: H 2 NCH 2 CH 2} SCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SCH 2 CH 2 NH 2
G1-20: H ₂ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NH ₂
G1-21: HOOC (NH ₂ ) CHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ CH (NH ₂ ) COOH
G1-22: HOOC (NH ₂ ) CHCH ₂ SCH ₂ CH ₂ OCH ₂ CH ₂ OCH ₂ CH ₂ SCH ₂ CH (NH ₂ ) COOH
G1-23: HOOC (NH ₂ ) CHCH ₂ OCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCH ₂ CH (NH ₂ ) COOH
_{G1-24: H 2 N (= O} ) CCH 2 SCH 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SCH 2 C (= O) NH 2
_{G1-25: H 2 N (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (O =) NH 2
_{G1-26: H 2 NHN (O =} ) CCH 2 SCH 2 CH 2 SCH 2 C (= O) NHNH 2
_{G1-27: H 3 C (O =} ) NHCH 2 CH 2 SCH 2 CH 2 SCH 2 CH 2 NHC (O =) CH 3
_{G1-28: H 2 NO 2 SCH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 SO 2 NH 2
_{G1-29: NaO 3 SCH 2 CH 2} CH 2 SCH 2 CH 2 SCH 2 CH 2 CH 2 SO 3 Na
G1-30: H ₃ CSO ₂ NHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHO ₂ SCH ₃
G1-31: H ₂ N (NH) CSCH ₂ CH ₂ SC (NH) NH ₂ .2HBr
_{G1-32: H 2 (NH) CSCH} 2 CH 2 OCH 2 CH 2 OCH 2 CH 2 SC (NH) NH 2 · 2HCl
G1-33: H ₂ N (NH) CNHCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ NHC (NH) NH ₂ .2HBr
G1-34: [(CH ₃ ) ₃ NCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ N (CH ₃ ) ₃ ] ₂ ⁺ · 2Cl ⁻
_{G1-35: CH 3 CH 2 CH 2} CH 2 OCH 2 CH 2 SCH 2 CH 2 SCH 2 CH 2 OCH 2 CH 2 CH 2 CH 3
_{G1-36: CH 3 CH 2 CH 2} CH 2 OCOCH 2 CH 2 SCH 2 CH 2 SCH 2 CH 2 OCOCH 2 CH 2 CH 2 CH 3
G1-37: NCCH ₂ CH ₂ CH ₂ OCOCH ₂ CH ₂ SCH ₂ CH ₂ SCH ₂ CH ₂ OCOCH ₂ CH ₂ CH ₂ CN

  Among the above-exemplified compounds, the exemplary compounds G1-3, G1-36, G1-40, G1-59, G1-68, G1-71, G1- 74, G1-77, and G1-86 are preferable.

  Next, the compound represented by General Formula (G2) will be described.

In the general formula (G2), M represents a hydrogen atom, a metal atom, or quaternary ammonium. Z represents a nitrogen-containing heterocyclic ring excluding imidazole rings. n represents an integer of 0 to 5, Rg ₂₁ represents a substituent, and when n is 2 or more, each Rg ₂₁ may be the same or different, and may be connected to each other to form a condensed ring. It may be formed.

Examples of the metal atom represented by M in the general formula (G2) include Li, Na, K, Mg, Ca, Zn, and Ag. Examples of the quaternary ammonium include NH ₄ , N (CH ₃ ) ₄ , N (C ₄ H ₉ ) ₄ , N (CH ₃ ) ₃ C 1 ₂ H ₂₅ , N (CH ₃ ) ₃ C ₁₆ H ₃₃ , N (CH ₃ ) ₃ CH ₂ C ₆ H _{5 and the} like It is done.

  Examples of the nitrogen-containing heterocycle having Z as a constituent in the general formula (G2) include, for example, a tetrazole ring, a triazole ring, an imidazole ring, an oxadiazole ring, a thiadiazole ring, an indole ring, an oxazole ring, a benzoxazole ring, and a benzimidazole. Ring, benzothiazole ring, benzoselenazole ring, naphthoxazole ring and the like.

The substituents represented by Rg ₂₁ of the general formula (G2), not particularly limited, but include for example substituents such as the following.

  Hydrogen atom, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, iodine atom), alkyl group (eg, methyl, ethyl, propyl, i-propyl, butyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl) Octyl, dodecyl, hydroxyethyl, methoxyethyl, trifluoromethyl, benzyl, etc.), aryl groups (eg, phenyl, naphthyl, etc.), alkylcarbonamide groups (eg, acetylamino, propionylamino, butyroylamino, etc.), aryl Carboxamide groups (eg, benzoylamino), alkylsulfonamide groups (eg, methanesulfonylamino group, ethanesulfonylamino group, etc.), arylsulfonamide groups (eg, benzenesulfonylamino group, toluenesulfonylamino) Group), alkoxy group, aryloxy group (for example, phenoxy), alkylthio group (for example, methylthio, ethylthio, butylthio, etc.), arylthio group (for example, phenylthio group, tolylthio group, etc.), alkylcarbamoyl group (for example, methylcarbamoyl group) Dimethylcarbamoyl, ethylcarbamoyl, diethylcarbamoyl, dibutylcarbamoyl, piperidylcarbamoyl, morpholylcarbamoyl, etc.), arylcarbamoyl groups (eg, phenylcarbamoyl, methylphenylcarbamoyl, ethylphenylcarbamoyl, benzylphenylcarbamoyl, etc.), carbamoyl groups, alkylsulfurates Famoyl groups (eg methylsulfamoyl, dimethylsulfamoyl, ethylsulfamoyl, diethylsulfamoyl, dibu Sulfamoyl, piperidylsulfamoyl, morpholylsulfamoyl, etc.), arylsulfamoyl groups (eg, phenylsulfamoyl, methylphenylsulfamoyl, ethylphenylsulfamoyl, benzylphenylsulfamoyl, etc.), sulfamoyl groups , Cyano group, alkylsulfonyl group (for example, methanesulfonyl group, ethanesulfonyl group, etc.), arylsulfonyl group (for example, phenylsulfonyl, 4-chlorophenylsulfonyl, p-toluenesulfonyl, etc.), alkoxycarbonyl group (for example, methoxycarbonyl, Ethoxycarbonyl, butoxycarbonyl etc.), aryloxycarbonyl group (eg phenoxycarbonyl etc.), alkylcarbonyl group (eg acetyl, propionyl, butyroyl etc.), a A reelcarbonyl group (for example, benzoyl group, alkylbenzoyl group, etc.), an acyloxy group (for example, acetyloxy, propionyloxy, butyroyloxy, etc.), a carboxyl group, a carbonyl group, a sulfonyl group, an amino group, a hydroxy group, or a heterocyclic group (for example, , Oxazole ring, thiazole ring, triazole ring, selenazole ring, tetrazole ring, oxadiazole ring, thiadiazole ring, thiazine ring, triazine ring, benzoxazole ring, benzthiazole ring, indolenine ring, benzselenazole ring, naphthothiazole ring , Triazaindolizine ring, diazaindolizine ring, tetraazaindolizine ring group, etc.). These substituents further include those having a substituent.

  Next, although the preferable specific example of a compound represented by general formula (G2) is shown, this invention is not limited to these compounds.

  Among the above-exemplified compounds, Exemplified Compounds G2-2, G2-12, and G2-20 are particularly preferable from the viewpoint that the objective effect of the present invention can be exhibited.

  In the electrolytic solution according to the present invention, the following components may be used in combination.

[Supporting electrolyte]
As the supporting electrolyte that can be used in the electrolytic solution according to the present invention, salts, acids, and alkalis that are usually used in the field of electrochemistry or the field of batteries can be used.

  There are no particular limitations on the salts, and for example, inorganic ion salts such as alkali metal salts and alkaline earth metal salts; quaternary ammonium salts; cyclic quaternary ammonium salts; quaternary phosphonium salts and the like can be used.

Specific examples of the salts include halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF _{^{6 -, AsF 6 -, CH}} 3 COO -, CH 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - Li salt having a counter anion selected from, Na salt or K salt is mentioned.

Further, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF _{6 ^{-, CH 3 COO -, CH}} 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - 4 quaternary ammonium salt having a counter anion selected from, specifically, (CH ₃ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBF ₄ , (n-C ₄ H ₉ ) ₄ NBF ₄ , (C ₂ H ₅ ) ₄ NBr, (C ₂ H ₅ ) ₄ NClO ₄ , (n- C ₄ H ₉ ) ₄ NClO ₄ , CH ₃ (C ₂ H ₅ ) ₃ NBF ₄ , (CH ₃ ) ₂ (C ₂ H ₅ ) ₂ NBF ₄ , (CH ₃ ) ₄ NSO ₃ CF ₃ , (C ₂ H _{5) 4 NSO 3 CF 3,} (n-C 4 H 9 ₄ NSO ₃ CF _3,
Furthermore, the following salts etc. are mentioned.

Further, halogen ions, SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , PF ₆ ⁻ , AsF _{6 ^{-, CH 3 COO -, CH}} 3 (C 6 H 4) SO 3 -, and _{(C 2 F 5 SO 2)} 3 C - phosphonium salt having a counter anion selected from, specifically, _(CH 3) ₄ PBF ₄ , (C ₂ H ₅ ) ₄ PBF ₄ , (C ₃ H ₇ ) ₄ PBF ₄ , (C ₄ H ₉ ) ₄ PBF _{4 and the} like. Moreover, these mixtures can also be used suitably.

  The supporting electrolyte according to the present invention is preferably a quaternary ammonium salt, and particularly preferably a quaternary spiro ammonium salt.

  The amount of the supporting electrolyte used is arbitrary, but generally, the supporting electrolyte is present in the solvent as an upper limit of 20 mol / l or less, preferably 10 mol / l or less, more preferably 5 mol / l or less. The lower limit is usually 0.01 mol / l or more, preferably 0.05 mol / l or more, more preferably 0.1 mol / l or more.

[Auxiliary compound that can be redox (promoter)]
In the display element of the present invention, an auxiliary compound (hereinafter referred to as a promoter) that can be oxidized and reduced may be added for the purpose of promoting dissolution and precipitation of a metal salt (particularly a silver salt). The promoter may be one that does not change the optical density in the visible region (400 to 700 nm) as a result of the oxidation-reduction reaction, or may be one that changes, that is, an electrochromic compound, and is immobilized on the electrode. Or may be added to the electrolyte layer.

Examples of preferred promoters that can be used in the present invention include the following compounds.
1) Compounds having N—O bonds, such as N-oxyl derivatives, N-hydroxyphthalimide derivatives, hydroxamic acid derivatives such as TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) A compound having an allyloxy free radical having a bulky substituent introduced at the 0-position, such as galvinoxyl, 3) ferrocene, a metallocene derivative,
4) benzyl (diphenylethanedione) derivative,
5) Tetrazolium salt / formazan derivative,
6) Azine compounds such as phenazine, phenothiazine, phenoxazine, acridine,
7) Pyridinium compounds such as viologen.

  In addition, hydrazyl free radical compounds such as benzoquinone derivatives, verdazyl, thiazyl free radical compounds, hydrazone derivatives, phenylenediamine derivatives, triallylamine derivatives, tetrathiafulvalene derivatives, tetracyanoquinodimethane derivatives, thianthrene derivatives, etc. can also be used as promoters. .

  In the display element of the present invention, promoters in the categories 1) and 3) are preferred, and ferrocene derivatives are particularly preferred.

[White scattered matter]
In the present invention, from the viewpoint of further increasing the display contrast and the white display reflectance, it is preferable to contain a white scattering material, and a porous white scattering layer may be formed and present.

  The porous white scattering layer applicable to the present invention is formed by applying and drying an aqueous mixture of an aqueous polymer and a white pigment that does not substantially dissolve in the solvent of the electrolyte layer (hereinafter also referred to as electrolyte solvent). can do.

  In the present invention, substantially insoluble in the electrolyte solvent is defined as a state in which the amount of solution per kg of electrolyte solvent is 0 g or more and 10 g or less at a temperature of −20 ° C. to 120 ° C. The amount of dissolution can be determined by a known method such as a component quantification method using a liquid chromatogram or a gas chromatogram.

  In the present invention, examples of the water-based polymer that does not substantially dissolve in the electrolyte solution solvent include a water-soluble polymer and a polymer dispersed in the water-based solvent.

Examples of water-soluble compounds include proteins such as gelatin and gelatin derivatives, or cellulose derivatives, natural compounds such as starch, gum arabic, dextran, pullulan, and carrageenan polysaccharides, polyvinyl alcohol, polyethylene glycol, polyvinyl pyrrolidone, and acrylamide polymers. And synthetic polymer compounds such as derivatives thereof. As gelatin derivatives, acetylated gelatin, phthalated gelatin, polyvinyl alcohol derivatives as terminal alkyl group-modified polyvinyl alcohol, terminal mercapto group-modified polyvinyl alcohol, and cellulose derivatives include hydroxyethyl cellulose, hydroxypropyl cellulose, carboxymethyl cellulose and the like. It is done. Furthermore, Research Disclosure and those described in pages (71) to (75) of JP-A No. 64-13546, US Pat. No. 4,960,681, JP-A No. 62-245260, etc. superabsorbent polymers described, namely -COOM or -SO 3 M _(M is a hydrogen atom or an alkali metal) homopolymer or a vinyl monomer together or with other vinyl monomers of the vinyl monomer having a (e.g., sodium methacrylate, Copolymers with ammonium acid, potassium acrylate, etc.) are also used. These binders can be used in combination of two or more.

  In the present invention, polyvinyl alcohol, polyethylene glycol, and polyvinylpyrrolidone compounds can be preferably used.

  Polymers dispersed in an aqueous solvent include latexes such as natural rubber latex, styrene butadiene rubber, butadiene rubber, nitrile rubber, chloroprene rubber, isoprene rubber, polyisocyanate, epoxy, acrylic, silicon, polyurethane, Examples thereof include a thermosetting resin in which urea, phenol, formaldehyde, epoxy-polyamide, melamine, alkyd resin, vinyl resin and the like are dispersed in an aqueous solvent. Of these polymers, it is preferable to use an aqueous polyurethane resin described in JP-A-10-76621.

  The average molecular weight of the water-based polymer according to the present invention is preferably in the range of 10,000 to 2,000,000 and more preferably in the range of 30,000 to 500,000 on a weight average basis.

  Examples of the white pigment applicable in the present invention include titanium dioxide (anatase type or rutile type), barium sulfate, calcium carbonate, aluminum oxide, zinc oxide, magnesium oxide and zinc hydroxide, magnesium hydroxide, magnesium phosphate, Magnesium hydrogen phosphate, alkaline earth metal salt, talc, kaolin, zeolite, acidic clay, glass, organic compounds such as polyethylene, polystyrene, acrylic resin, ionomer, ethylene-vinyl acetate copolymer resin, benzoguanamine resin, urea-formalin resin, A melamine-formalin resin, a polyamide resin, or the like may be used alone or in combination, or in a state having voids that change the refractive index in the particles.

In the present invention, among the white particles, titanium dioxide is preferably used. In particular, titanium dioxide surface-treated with an inorganic oxide (Al ₂ O ₃ , AlO (OH), SiO _2, etc.), in addition to these surface treatments. Titanium dioxide that has been treated with an organic substance such as trimethylcyclosilane is more preferably used.

  Of these white particles, it is more preferable to use titanium oxide or zinc oxide from the viewpoint of coloring prevention at high temperature and the reflectance of the element due to the refractive index.

  In the present invention, the water mixture of the water-based compound and the white pigment is preferably in a form in which the white pigment is dispersed in water according to a known dispersion method. The mixing ratio of the aqueous compound / white pigment is preferably 1 to 0.01, more preferably 0.3 to 0.05 in terms of volume ratio.

  The thickness of the porous white scattering layer is preferably in the range of 5 to 50 μm, more preferably in the range of 10 to 30 μm.

  As the alcohol solvent, a compound having high solubility in water such as methanol, ethanol, isopropanol is preferably used, and the mixing ratio with the water / alcohol solvent is preferably in the range of 0.5 to 20 by mass ratio, More preferably, it is the range of 2-10.

[Solid electrolyte, gel electrolyte]
The electrolytic solution that can be used in the display device of the present invention is a high-viscosity electrolytic solution containing a solid electrolytic solution or a polymer compound that does not substantially contain a solvent, in addition to a solution-like electrolytic solution composed of a solvent or an ionic liquid. Liquid or gel electrolyte (hereinafter referred to as gel electrolyte).

  Examples of the solid electrolyte solution and gel electrolyte solution applicable to the present invention include a solid electrolyte solution described in JP-A-2002-341387, a polymer solid electrolyte solution described in JP-A-2002-341387, and JP-A-2004. -20928, a solid polymer electrolyte described in JP2004-191945, a solid polymer electrolyte described in JP2005-338204, and JP2006-323022 Examples thereof include a polymer solid electrolyte solution described in Japanese Patent Publication No. 2007-141658, a solid electrolyte solution described in Japanese Patent Application Publication No. 2007-141658, a solid electrolyte solution described in Japanese Patent Application Publication No. 2007-163865, a gel electrolyte solution, and the like.

[Thickener for electrolyte layer addition]
In the display element of the present invention, a thickener can be used in the electrolyte layer. For example, gelatin, gum arabic, poly (vinyl alcohol), hydroxyethyl cellulose, hydroxypropyl cellulose, cellulose acetate, cellulose acetate butyrate, Poly (vinyl pyrrolidone), poly (alkylene glycol), casein, starch, poly (acrylic acid), poly (methyl methacrylic acid), poly (vinyl chloride), poly (methacrylic acid), copoly (styrene-maleic anhydride), Copoly (styrene-acrylonitrile), copoly (styrene-butadiene), poly (vinyl acetal) s (eg, poly (vinyl formal) and poly (vinyl butyral)), poly (esters), poly (urethanes), phenoxy resins , Poly (chloride Nylidene), poly (epoxides), poly (carbonates), poly (vinyl acetate), cellulose esters, poly (amides), hydrophobic transparent binders such as polyvinyl butyral, cellulose acetate, cellulose acetate butyrate, polyester, Examples include polycarbonate, polyacrylic acid, polyurethane and the like.

  These thickeners may be used in combination of two or more. Moreover, the compound as described in pages 71-75 of Unexamined-Japanese-Patent No. 64-13546 can be mentioned. Among these, the compounds preferably used are polyvinyl alcohols, polyvinyl pyrrolidones, hydroxypropyl celluloses, and polyalkylene glycols from the viewpoint of compatibility with various additives and improvement in dispersion stability of white particles.

  In the display element of the present invention, polyethylene glycol having an average polymerization degree of 100 to 500 is preferable as the thickener, and it is added in a range of 5 to 20% by mass ratio with respect to the organic solvent of the electrolyte layer. preferable.

[Other components of the display element]
In the display element of the present invention, a sealant, a columnar structure, and spacer particles can be used as necessary.

  Sealing agent is for sealing so that it does not leak outside and is also called sealing agent. Epoxy resin, urethane resin, acrylic resin, vinyl acetate resin, ene-thiol resin, silicon resin, modified resin A curing type such as a polymer resin, such as a thermosetting type, a photocurable type, a moisture curable type, and an anaerobic curable type can be used.

  The columnar structure provides strong self-holding (strength) between the substrates, for example, a columnar body, a quadrangular columnar body, an elliptical columnar body, a trapezoidal array arranged in a predetermined pattern such as a lattice arrangement. A columnar structure such as a columnar body can be given. Alternatively, stripes arranged at predetermined intervals may be used. This columnar structure is not a random array, but can be properly maintained at intervals of the substrate, such as an evenly spaced array, an array in which the interval gradually changes, and an array in which a predetermined arrangement pattern is repeated at a constant period. The arrangement is preferably considered so as not to disturb the display. If the ratio of the area occupied by the columnar structure in the display area of the display element is 1 to 40%, a practically sufficient strength as a display element can be obtained.

  A spacer may be provided between the pair of substrates for uniformly maintaining a gap between the substrates. Examples of the spacer include a sphere made of resin or inorganic oxide. Further, a fixed spacer having a surface coated with a thermoplastic resin is also preferably used. In order to hold the gap between the substrates uniformly, only the columnar structure may be provided, but both the spacer and the columnar structure may be provided, or instead of the columnar structure, only the spacer is used as the space holding member. May be used. The diameter of the spacer is equal to or less than the height of the columnar structure, preferably equal to the height. When the columnar structure is not formed, the diameter of the spacer corresponds to the thickness of the cell gap.

[Display element driving method]
The driving operation of the display element of the present invention may be simple matrix driving or active matrix driving. The simple matrix driving in the present invention is a driving method in which a current is sequentially applied to a circuit in which a positive line including a plurality of positive electrodes and a negative electrode line including a plurality of negative electrodes are opposed to each other in a vertical direction. Say that. By using simple matrix driving, there is an advantage that the circuit configuration and driving IC can be simplified and manufactured at low cost. The active matrix drive is a system in which scanning lines, data lines, and current supply lines are formed in a grid pattern, and are driven by TFT circuits provided in each grid pattern. Since switching can be performed for each pixel, there are merits such as gradation and memory function. For example, a circuit described in FIG. 5 of JP-A-2004-29327 can be used.

[Product application]
The display element of the present invention can be used in an electronic book field, an ID card field, a public field, a traffic field, a broadcast field, a payment field, a distribution logistics field, and the like. Specifically, keys for doors, student ID cards, employee ID cards, various membership cards, convenience store cards, department store cards, vending machine cards, gas station cards, subway and railway cards, bus cards, Cash cards, credit cards, highway cards, driver's licenses, hospital examination cards, electronic medical records, health insurance cards, Basic Resident Registers, passports, electronic books, etc.

EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.
Example 1
<< Production of display element >>
<Analysis and cleaning of titanium dioxide>
Titanium dioxide (CR-95, manufactured by Ishihara Sangyo Co., Ltd.) is added to the water / n-butanol mixed solution so as to be 20% by mass, and is ultrasonically dispersed with an ultrasonic disperser for 30 minutes. And the supernatant was removed. After repeating this operation five times, the obtained titanium oxide was dried at 120 ° C. for 8 hours to obtain washed titanium oxide. Further, the supernatant was concentrated and analyzed by gas chromatography, liquid chromatography, mass measurement, nuclear magnetic resonance spectrum, etc. As a result, it was found that a trace amount of trimethylolpropane (TMP) was contained.

[Production of display-side electrode]
[Preparation of electrode 1]
A 300 nm-thick ITO (Indium Tin Oxide) film was formed on a 2 cm × 4 cm glass substrate having a thickness of 1.5 mm according to a sputtering method to obtain a transparent electrode (electrode 1).

[Preparation of counter electrode]
(Preparation of electrode 2)
On the electrode produced in the same manner as the electrode 1, 30 mC / cm ^{2 of} silver was formed by sputtering to produce the electrode 2.

(Preparation of electrolyte)
(Preparation of electrolyte 1-1)
50 g of γ-butyrolactone, 5 g of the following lithium trifluoromethanesulfonate imide as the supporting electrolyte, 4.0 g of silver trifluoromethanesulfonate as the metal salt compound, 20 g of the silver salt solvent G1-74, and 1 g of G2-12, ferrocene 50 mg and 3.0 g of PEG 20,000 were dissolved, and 90 g of the washed titanium dioxide was further added and mixed well to obtain an electrolytic solution 1.

(Preparation of electrolytes 1-2 to 1-7)
In the preparation of the electrolytic solution 1-1, trimethylolpropane (hereinafter referred to as TMP) was added as shown in Table 1 below, and the amount of PEG 20,000 was changed. Thus, electrolytic solutions 1-2 to 1-10 were prepared. In addition, the amount of TMP in each electrolyte solution was measured by gas chromatography. The results are also shown in Table 1. In addition, the moisture content of each electrolyte solution was the range of 3000-4000 ppm.

[Production of display element]
(Preparation of display element 1-1)
After the periphery of the electrode 2 is edged with an olefin-based sealant containing 10% glass spherical beads having an average particle diameter of 40 μm as a volume fraction, the striped electrodes are orthogonal to the electrodes 2 and 1 respectively. The cells were bonded together and further heated and pressed to produce an empty cell. The electrolyte layer composition 1 was vacuum-injected into the empty cell, and the inlet was sealed with an epoxy-based ultraviolet curable resin to produce a display element 1-1.

(Production of display elements 1-2 to 1-7)
Display elements 1-2 to 1-7 were manufactured in the same manner as the display element 1-1 except that the electrolyte solution 1-1 was changed to the electrolyte solutions 1-2 to 1-7, respectively.

[Evaluation of display element]
[Evaluation of repeated driving durability]
One cycle is an operation in which both electrodes of the display element are connected to both terminals of a constant voltage power source, a voltage of +1.2 V is applied for 2.0 seconds, and then a voltage of -1.5 V is applied for 2.0 seconds. The reflectance at a wavelength of 550 nm after applying +1.2 V and the reflectance at a wavelength of 550 nm after applying -1.5 V were measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing, and the contrast was obtained from the following formula. CR1.
Contrast: CR1 = (reflectance after applying + 1.5V) / (reflectance after applying -1.5V)
Under the same driving conditions, the contrast was measured every 10 times of driving, and the number of times of driving when the contrast at each measurement was 50% of CR1 was recorded, and the number of times of repeated driving was recorded. After 100 times of driving, the contrast was measured every 100 times of driving. The number of times of driving was measured with an upper limit of 1000 times.

  Table 1 shows the configuration and evaluation results of each display element obtained as described above.

As is apparent from the results of Table 1, the display element using the electrolytic solution of the present invention has a certain content of a compound (here, TMP) having three or more OH groups bonded to carbon atoms in the electrolytic solution. It has been clarified that the repeated driving durability can be improved by limiting the amount to the amount or less.
(Example 2)
(Preparation of electrolyte 2-1)
In the preparation of the electrolytic solution 1-1, the electrolytic solution 2-1 was prepared in the same manner except that the water content of each material was reduced by distillation or drying under reduced pressure before the adjustment, and the preparation was performed in a glove box.

(Preparation of electrolytes 2-2 to 2-13)
As shown in Table 2 below, the electrolytic solution 2-1 was prepared by preparing the electrolytic solution 2-1, except that trimethylolpropane, hexanetricarboxylic acid, and 2,2-dimethylolacetic acid were added. Similarly, electrolytic solutions 2-2 to 2-13 were prepared. In addition, the moisture content of each electrolyte solution was 50 ppm or less.

(Preparation of display elements 2-1 to 2-13)
Display elements 2-1 to 2-13 were produced in the same manner as in the production of the display element 1-1 except that the electrolytic solution 1-1 was changed to electrolytic solutions 2-1 to 2-10, respectively.

(Preparation of display elements 2-14 to 2-18)
After producing the display elements 2-1 to 2-5, the electrolytic solutions 2-1 to 2-4 were put in a sample tube, returned to the air, and left for 24 hours. This was again put in the glove box, and display elements 2-14 to 2-18 were produced in the same manner as the display elements 2-1 to 2-5. When the moisture content of the electrolyte solutions 2-14 to 2-18 was measured after creating the display element, the moisture content of each electrolyte solution was in the range of 100 to 200 ppm.

[Evaluation of display element]
[Evaluation of repeated driving durability]
One cycle is an operation in which both electrodes of the display element are connected to both terminals of a constant voltage power source, a voltage of +1.2 V is applied for 1.5 seconds, and then a voltage of -1.5 V is applied for 1.0 second. The reflectance at a wavelength of 550 nm after applying +1.2 V and the reflectance at a wavelength of 550 nm after applying -1.5 V were measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing, and the contrast was obtained from the following formula. CR1.
Contrast: CR1 = (reflectance after applying + 1.5V) / (reflectance after applying -1.5V)
Under the same driving conditions, the contrast was measured every 200 times of driving, and the number of times of driving when the contrast during each measurement was 80% or less of CR1 was recorded, and the number of times of repeated driving was recorded. The number of times of driving was measured with an upper limit of 10,000 times. The results are shown in Table 2.

As is apparent from the results in Table 2, the display element using the electrolytic solution of the present invention contains a compound containing three or more OH groups or COOH groups bonded to carbon atoms in the electrolytic solution in a certain amount or less. It is clear that the repeated driving durability is improved by suppressing to the above. In addition, repeated drive durability could be further improved by reducing the water content at the same time as suppressing compounds containing three or more OH groups and COOH groups bonded to carbon atoms in the electrolyte.
(Example 3)
(Preparation of electrolyte 3)
In preparation of the electrolytic solution 2-1, in place of washed titanium dioxide, titanium dioxide not treated with a compound containing three or more OH groups and COOH groups bonded to carbon atoms (manufactured by Ishihara Sangyo Co., Ltd., CR-93) ) Was used in the same manner except that it was used after drying at 120 ° C. for 8 hours.

(Preparation of display elements 2-1, 2-2 and display element 3)
In the production of the display element 1-1, the display element 2-1, the display element 2- 2 and two display elements 3 were produced.

[Evaluation of display element]
[Evaluation of repeated driving durability]
One cycle is an operation in which both electrodes of the display element are connected to both terminals of a constant voltage power source, a voltage of +1.2 V is applied for 1.5 seconds, and then a voltage of -1.5 V is applied for 1.0 second. The reflectance at a wavelength of 550 nm after applying +1.2 V and the reflectance at a wavelength of 550 nm after applying -1.5 V were measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing, and the contrast was obtained from the following formula. CR1.
Contrast: CR1 = (reflectance after applying + 1.5V) / (reflectance after applying -1.5V)
Under the same driving conditions, the contrast was measured every 200 times of driving, and the number of times of driving when the contrast during each measurement was 80% or less of CR1 was recorded, and the number of times of repeated driving was recorded. The number of times of driving was measured with an upper limit of 10,000 times. The number of repeated drivings of the display element 2-1 and the display element 2-2 was 10,000 as in Example 2, but the number of repeated driving of the display element 3 was 7800.

[Evaluation of storage stability]
The display element 2-1, the display element 2-2, and the display element 3 manufactured as described above were each left for 10 days with the display-side electrode facing upward and shielded from light, and the sample after the stand was visually observed.

  In the display elements 2-1 and 2-2, no change was observed compared to before storage, but a plurality of cracks occurred in the display element 3. Further, the number of times of repeated driving was measured under the same driving conditions as described above. Although the display elements 2-1 and 2-2 were able to be repeatedly driven 10,000 times as before storage, the display element 3 was repeatedly driven. The number of times was 400, and the seizure presumed to be caused by cracks occurred.

As described above, the display element using the electrolytic solution of the present invention improves the storage stability by containing a certain amount or more of a compound containing three or more OH groups or COOH groups bonded to carbon atoms in the electrolytic solution. It is clear.
Example 4
<< Production of display element >>
[Production of display-side electrode]
[Preparation of electrode 3]
The electrode 1 prepared above is immersed in a solution of 0.2 g of acetic acid, 2.0 g of pure water, and 10 g of methanol, and a solution obtained by dissolving 0.1 g of the following compound (1) in 2.0 g of methanol is added. After impregnation for 1 hour, the electrode 3 was produced by washing with ethanol and drying to modify the electrochromic compound on the electrode 1.

(Preparation of electrolyte)
(Preparation of electrolyte 4-1)
In 25 g of acetonitrile, 0.5 g of tetrabutylammonium perchlorate, 0.5 g of carboxy TEMPO (4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl free radical), and 201.5 g of PEG After mixing, 15 g of the washed titanium dioxide prepared in Example 1 was added to prepare an electrolytic solution 4-1.

(Preparation of electrolytic solution 4-2)
In preparation of the electrolytic solution 4-1, titanium dioxide not treated with a compound containing three or more OH groups and COOH groups bonded to carbon atoms instead of washed titanium dioxide (manufactured by Ishihara Sangyo Co., Ltd., CR-93) The electrolytic solution 4-2 was prepared in the same manner except that it was dried at 120 ° C. for 8 hours.

(Preparation of electrolyte 4-3)
In the preparation of the electrolytic solution 4-1, an electrolytic solution 4-3 was prepared in the same manner as the electrolytic solution 4-1, except that 0.2 g of trimethylolpropane was further added.

(Preparation of electrolyte 4-4)
In the preparation of the electrolytic solution 4-1, an electrolytic solution 4-4 was prepared in the same manner as the electrolytic solution 4-1, except that 0.6 g of trimethylolpropane was further added.

(Preparation of electrolyte 4-5)
In the preparation of the electrolytic solution 4-1, an electrolytic solution 4-5 was prepared in the same manner as the electrolytic solution 4-1, except that 0.5 g of 2,3-dihydroxybutanoic acid was further added.

[Production of display element]
(Preparation of display element 4-1)
After the periphery of the electrode 1 is edged with an olefin-based sealant containing glass spherical beads having an average particle diameter of 40 μm as a volume fraction of 10%, the striped electrodes are orthogonal to the electrodes 3 and 1 respectively. The cells were bonded together and further heated and pressed to produce an empty cell. The electrolyte solution 4-1 was vacuum-injected into the empty cell, and the injection port was sealed with an epoxy-based ultraviolet curable resin, to produce a display element 4-1. In the same manner, a total of two identical display elements were produced.

(Preparation of display element 4-2)
Two display elements 4-2 were prepared in the same manner as the display element 4-1, except that the electrolyte solution 4-2 was vacuum-injected instead of the electrolyte solution 4-1.

(Preparation of display element 4-3)
Two display elements 4-3 were prepared in the same manner as the display element 4-1, except that the electrolyte solution 4-3 was vacuum-injected instead of the electrolyte solution 4-1.

(Preparation of display element 4-4)
Two display elements 4-4 were prepared in the same manner as the display element 4-1, except that the electrolyte solution 4-4 was vacuum-injected instead of the electrolyte solution 4-1.

(Preparation of display element 4-5)
Two display elements 4-5 were prepared in the same manner as the display element 4-1, except that the electrolyte solution 4-5 was vacuum-injected instead of the electrolyte solution 4-1.

[Evaluation of display element]
[Evaluation of the number of repeated driving]
When both electrodes of the manufactured display element are connected to both terminals of a constant voltage power source, a voltage of -1.5 V is applied to the transparent electrode side for 1.0 second, and then a voltage of +1.5 V is applied for 0.5 second The reflectance (R _color ) at the maximum absorption wavelength in the visible light region and the reflectance at the same wavelength in the white state (R _white ) are measured with a spectrocolorimeter CM-3700d manufactured by Konica Minolta Sensing Co., Ltd. The rate difference ΔR (ΔR = (R _white ) − (R _color )) was measured, and this was taken as ΔR1. Under the same driving conditions, the reflectance difference is measured every 10 times of driving, and after 100 times of driving, measurement is performed every 100 times of driving, and the driving is performed until the reflectance difference at each measurement becomes 1/2 of ΔR1. Went. Note that the measurement was performed up to 1000 times. The results are shown in Table 3 below.

[Evaluation of storage stability]
The display elements 4-1 to 4-5 produced above were each left for 10 days with the display-side electrode facing upward and shielded from light, and the samples after being left were visually observed for cracks. Further, the sample after storage was evaluated by the same method as the above evaluation of the number of times of repeated driving. The results are also shown in Table 3 below.

  As apparent from the results of Table 3 above, when the electrolytic solution of the present invention is applied to an EC display element, the content of the compound containing three or more OH groups or COOH groups bonded to carbon atoms in the electrolytic solution is as follows. It is clear that repeated driving durability is improved by making the amount less than a certain amount. In addition, by containing more than a certain amount of compound containing three or more OH groups or COOH groups bonded to carbon atoms in the electrolyte, it is possible to prevent the occurrence of cracks after storage and maintain the number of repeated driving. Thus, it has been clarified that the storage stability is improved also in the EC display element.

Claims (7)

An electrolytic solution containing a non-aqueous solvent and inorganic fine particles, which has a compound containing three or more OH groups or COOH groups bonded to carbon atoms, and the content of the compound is 10 with respect to the total electrolytic solution mass. Electrolyte characterized by being not less than ppm by mass and not more than 1.0% by mass. 2. The electrolytic solution according to claim 1, wherein a content of the compound is 10 mass ppm or more and 0.5 mass% or less with respect to a total electrolytic solution mass. The electrolyte solution according to claim 1 or 2, comprising inorganic fine particles treated with the compound. The electrolytic solution according to any one of claims 1 to 3, wherein a moisture content of the electrolytic solution is 200 ppm or less. 4. The electrolytic solution according to claim 1, wherein a water content of the electrolytic solution is 50 ppm or less. An electrochemical device using the electrolytic solution according to any one of claims 1 to 5. The electrochemical device according to claim 6, wherein the electrochemical device is an electrochromic display element or an electrodeposition display element.