JPWO2018061600A1 - Optical functional film, thermochromic film, thermochromic laminate, and method for producing thermochromic film - Google Patents

Abstract

An optical functional film, a thermochromic film, a thermochromic laminate, and a method for producing a thermochromic film exhibiting excellent thermochromic properties and durability are provided. The optical functional film (1) of the present invention is an optical functional film containing vanadium dioxide particles (VO) exhibiting thermochromic properties, the vanadium dioxide particles (VO), a sulfur-containing compound, and a metal-containing surface modification. It contains an agent and a binder (B1).

Description

  The present invention relates to an optical functional film, a thermochromic film, a thermochromic laminate, and a method for producing a thermochromic film. More specifically, the present invention relates to an optical functional film or the like that exhibits excellent thermochromic properties and durability.

In recent years, in order to reduce the heat felt by human skin due to the influence of sunlight entering from a car window, laminated glass having high heat insulating properties or heat shielding properties has been distributed in the market. Recently, with the spread of electric vehicles and the like, development of near-infrared light (heat ray) shielding films applied to laminated glass has been actively conducted from the viewpoint of increasing the cooling efficiency in the vehicle.
The near-infrared light shielding film can be applied to a vehicle body or a window glass of a building to reduce a load on a cooling facility such as an air conditioner in the vehicle, and is an effective means for energy saving.

  As such a near infrared light shielding film, an optical film containing a conductor such as ITO (indium tin oxide) as an infrared absorbing substance is disclosed. Patent Document 1 discloses a near-infrared light shielding film including a functional plastic film having an infrared reflection layer and an infrared absorption layer. Furthermore, Patent Document 2 has a reflection layer laminate in which a large number of low refractive index layers and high refractive index layers are alternately laminated, and by adjusting the layer thickness of each refractive index layer, near infrared light can be obtained. A near-infrared light shielding film that selectively reflects light has been proposed.

  The near-infrared light shielding film having such a configuration is preferably used due to its high near-infrared light shielding effect in a low-latitude zone near the equator where the illuminance of sunlight is high. However, in the mid-latitude to high-latitude winter season, there is a problem that incident light is uniformly shielded even when it is desired to capture sunlight as much as possible in the vehicle or in the room.

In order to solve such a problem, a method of applying a thermochromic material in which the optical properties of near-infrared light shielding and transmission are controlled by temperature has been studied. A typical material is vanadium dioxide (hereinafter also referred to as “VO ₂ ”). VO ₂ is known to cause a phase transition in a temperature range of about 50 to 60 ° C. and exhibit thermochromic properties.
However, VO ₂ is known to promote the oxidation of VO ₂ and the change in crystal structure by moisture and oxygen in the atmosphere. In thermochromic films containing VO ₂ particles, thermochromic properties over time Has become a problem.

Thus, for example, Patent Document 3 reports that VO ₂ is protected with a silane coupling agent and a long-chain alkyl resin, and Patent Document 4 reports that VO ₂ is protected with a polycarboxylic acid. However, when the inventor produced a thermochromic film containing these protected VO ₂ particles and conducted a durability test, it was found that the durability was insufficient.

JP 2010-222233 A International Publication No. 2013/065679 Special table 2015-513508 gazette JP 2012-25629 A

  The present invention has been made in view of the above-described problems and circumstances, and the solution to the problem is an optical functional film exhibiting excellent thermochromic properties and durability, a thermochromic film, and a thermochromic laminate including the same as a constituent element. It is providing the manufacturing method of a body and a thermochromic film.

As a result of studying to solve the above problems, the present inventors have found that the optical functional film containing at least a sulfur-containing compound and a metal-containing surface modifier has improved wet heat resistance and can maintain excellent thermochromic properties for a long period of time. As a result, the present invention has been achieved.
That is, the said subject of this invention is solved by the following means.

1. An optical functional film containing vanadium dioxide particles exhibiting thermochromic properties,
An optical functional film comprising the vanadium dioxide particles, a sulfur-containing compound, a metal-containing surface modifier, and a binder.

  2. A thermochromic film, wherein the optical functional film according to item 1 is provided on a substrate.

  3. The thermochromic film according to item 2, which contains thiols as the sulfur-containing compound.

  4). The thermochromic film according to Item 2 or 3, wherein the sulfur-containing compound contains a sulfur-containing primary amine.

  5. The thermochromic film according to any one of Items 2 to 4, wherein the metal-containing surface modifier contains a metal complex.

  6). The thermochromic film according to any one of Items 2 to 5, which contains a metal alkoxide compound as the metal-containing surface modifier.

  7). The thermochromic film according to any one of Items 2 to 6, which contains a titanate alkoxide compound as the metal-containing surface modifier.

  8). The thermochromic film according to any one of Items 2 to 7, wherein the sulfur-containing compound contains cysteine.

  9. The thermochromic film according to any one of Items 2 to 8, which contains 2-aminothiazole as the sulfur-containing compound.

  10. The content concentration of the sulfur-containing compound is in the range of 1 to 15% by mass with respect to the total mass of the thermochromic film, according to any one of items 2 to 9, Thermochromic film.

  11. A thermochromic laminate, wherein the thermochromic film according to any one of Items 2 to 10 is provided on a substrate.

  12 It is a manufacturing method of the thermochromic film which manufactures the thermochromic film as described in any one of Claim 2 to 10, Comprising: The vanadium dioxide particle which shows the thermochromic property synthesize | combined by the hydrothermal reaction is contained. A method for producing a thermochromic film, comprising a step of forming an optical functional film.

  By the above means of the present invention, it is possible to provide an optical functional film exhibiting excellent thermochromic properties and durability, a thermochromic film, a thermochromic laminate including the same, and a method for producing a thermochromic film.

The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.
It is considered that the vanadium dioxide particles are oxidized by moisture and oxygen to change the structure and lower the thermochromic properties.
If a compound containing sulfur or nitrogen is present in the vicinity of the vanadium dioxide particles, it is considered that the sulfur atom or nitrogen atom can form a coordinate bond with the vanadium atom and stabilize vanadium dioxide. Further, when a metal-containing surface modifier is present in the vicinity of the vanadium dioxide particles, a reactive group derived from the metal-containing surface modifier has a reaction or interaction with vanadium at a location different from the above-described coordination bond region, and thus dioxide dioxide. It is thought that vanadium is further stabilized.
That is, it is considered that the vanadium dioxide surface can be closely protected by using the sulfur-containing compound and the metal-containing surface modifier in combination, and the structural change due to oxidation of the vanadium dioxide particles is suppressed. Thereby, it is speculated that an optical functional film, a thermochromic film, and a thermochromic laminate exhibiting excellent thermochromic properties and durability were obtained.

Schematic sectional view showing an example of the configuration of the thermochromic film of the present invention Schematic sectional view showing an example of the configuration of the thermochromic film of the present invention

  The optical functional film of the present invention is an optical functional film containing vanadium dioxide particles exhibiting thermochromic properties, comprising the vanadium dioxide particles, a sulfur-containing compound, a metal-containing surface modifier, and a binder. It is characterized by being. This feature is a technical feature common to the claimed invention.

  As an embodiment of the present invention, the optical functional film of the present invention is preferably provided on a base material from the viewpoint of the effects of the present invention.

  As an embodiment of the present invention, it is preferable that thiols are contained as the sulfur-containing compound because of its high adsorptivity to vanadium dioxide particles.

  As an embodiment of the present invention, it is preferable that a sulfur-containing primary amine is contained as the sulfur-containing compound from the viewpoint of more effectively expressing the effects of the present invention.

  As an embodiment of the present invention, it is preferable to contain a metal complex as the metal-containing surface modifier in order to form a chemical bond with vanadium and further improve the heat and moisture resistance.

  As an embodiment of the present invention, it is preferable that a metal alkoxide compound is contained as the metal-containing surface modifier from the viewpoint of more effectively expressing the effects of the present invention.

  As an embodiment of the present invention, it is preferable that a titanate alkoxide compound is contained as the metal-containing surface modifier from the viewpoint of more effectively expressing the effects of the present invention.

  As an embodiment of the present invention, it is preferable that cysteine is contained as the sulfur-containing compound from the viewpoint of more effectively expressing the effects of the present invention.

  As an embodiment of the present invention, it is preferable that 2-aminothiazole is contained as the sulfur-containing compound from the viewpoint of more effectively expressing the effects of the present invention.

  As an embodiment of the present invention, from the viewpoint of more effectively expressing the effects of the present invention, the concentration of the sulfur-containing compound is in the range of 1 to 15% by mass relative to the total mass of the thermochromic film. It is preferable.

  The thermochromic laminate of the present invention is preferably provided with the thermochromic film of the present invention on a substrate from the viewpoint of more effectively expressing the effects of the present invention.

  The method for producing a thermochromic film of the present invention has a step of forming an optical functional film containing vanadium dioxide particles exhibiting thermochromic properties synthesized by a hydrothermal reaction, so that the effect of the present invention is more effectively expressed. From the viewpoint of making it.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, "-" shown in the following description is used with the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<Optical function film>
The optical functional film of the present invention is an optical functional film containing vanadium dioxide particles exhibiting thermochromic properties, comprising the vanadium dioxide particles, a sulfur-containing compound, a metal-containing surface modifier, and a binder. It is characterized by being.

《Thermochromic film》
As for the thermochromic film of this invention, it is preferable that the optical function film | membrane is provided on the base material.

A thermochromic film 1 of the present invention shown in FIG. 1 has a configuration in which an optical functional film 3 is laminated on a transparent substrate 2. This optical functional film 3 is present in a state where vanadium dioxide particles are dispersed in the resin binder B1 contained in the optical functional film. This is vanadium dioxide particles, constitute the primary particles VO _S of vanadium dioxide vanadium dioxide particles are present independently, an aggregate of two or more vanadium dioxide particles (also called aggregates), VO ₂ of secondary particles VO _M is present. In the present invention, an aggregate of two or more vanadium dioxide particles is collectively referred to as secondary particles, and is also referred to as secondary particle aggregates or secondary aggregate particles.

The thermochromic film shown in FIG. 2 is composed of a hybrid thermochromic layer (2 + 3) in which the transparent substrate 2 and the optical functional film 3 shown in FIG. 1 are composed of the same layer. As the resin constituting the transparent substrate, using a binder resin B2 is added to the optical functional film, in the binder resin B2, and VO ₂ particles primary particles VO _S of the VO _2, above vanadium dioxide particles secondary particles VO _M is dispersed, is configured to form a thermochromic layer having both a transparent substrate in a single layer.
In addition, the thermochromic film of the structure shown in FIG. 2 can also be obtained by peeling the optical functional film 3 of the thermochromic film 1 shown in FIG. 1 from the transparent base material 2 (for example, glass base material). The thermochromic film having the configuration shown in FIG.
Hereinafter, the detail of the material which comprises the thermochromic film of this invention is demonstrated.

  [Vanadium dioxide]
  Vanadium dioxide according to the present invention is an embodiment of vanadium oxide. Vanadium oxide takes various forms in nature, and V₂O₅, H₃V₂O₇ ⁻, H₂VO₄ ⁻, HVO₄ ^2-, VO₄ ^3-, VO²⁺, VO₂, V³⁺, V₂O₃, V²⁺, V₂O₂, V and the like. The form changes depending on the environmental atmosphere.₂O₅V in a reducing environment₂O₃Is formed. Therefore, VO₂Is relatively easy to oxidize and reduce, and its crystal structure changes depending on the surrounding environment.
  VO showing thermochromic properties (automatic light control)₂Is expressed in a monoclinic structure, so that VO used in the present invention₂Is monoclinic.

[Vanadium dioxide particles]
The crystal form of the vanadium dioxide particles used in the present invention is preferably a rutile type from the viewpoint of efficiently expressing thermochromic properties.
Rutile-type VO ₂ particles (hereinafter also simply referred to as VO ₂ particles) have a monoclinic structure below the transition temperature and are therefore also called M-type. The vanadium dioxide particles according to the present invention may contain VO ₂ particles of other crystal types such as A-type or B-type within a range that does not impair the purpose.
The VO ₂ particles according to the present invention are preferably present in a thermochromic film in such a manner that the number average particle diameter of the primary particles and secondary particles is less than 500 nm.
Various measurement methods can be applied to the particle diameter measurement method, but it is preferable to measure according to the dynamic light scattering method.

The preferred number average particle diameter of the primary particles and secondary particles in the VO ₂ particles according to the present invention is less than 500 nm, more preferably in the range of 1 to ₂₀₀ nm, and more preferably in the range of 5 to 100 nm. And most preferably in the range of 5 to 60 nm.
The aspect ratio of the VO ₂ particles is preferably in the range of 1.0 to 3.0.
The VO ₂ particles having such characteristics have a sufficiently small aspect ratio and isotropic shape, and therefore have good dispersibility when added to a solution. In addition, since the particle diameter of the single crystal is sufficiently small, better thermochromic properties can be exhibited compared to conventional particles.

In the VO ₂ particles according to the present invention, in addition to VO ₂ , for example, tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), iridium (Ir ), Osmium (Os), ruthenium (Ru), germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F) and phosphorus (P). It may contain at least one selected element. By adding such an element, it becomes possible to control the phase transition characteristics (particularly the dimming temperature) of the vanadium dioxide particles. In addition, about 0.1-5.0 atomic% is sufficient for the total amount of such an additive with respect to the vanadium dioxide particle finally obtained with respect to a vanadium (V) atom.

[Sulfur-containing compounds]
The thermochromic film of the present invention contains a sulfur-containing compound having adsorptivity to vanadium dioxide particles.
The sulfur-containing compound used in the present invention is not particularly limited, and any sulfur-containing compound may be used as long as it can be adsorbed on the surface of the vanadium dioxide particles and can improve the heat and humidity resistance. Contributes to the adsorptivity. Examples of the sulfur-containing compound include compounds containing thiol group, sulfonyl group, sulfoxide, sulfilimine, sulfonium salt, disulfide, sulfide, thiocarbonyl compound, thiazole ring, thiadiazole ring and the like. Although a thiol type is particularly preferred, there is an effect as long as a sulfur atom is contained, and there is no particular limitation. Moreover, if there exists an amine functional group, it is still more preferable, and it is more preferable that it is a primary amine.
Moreover, it is preferable that the sulfur containing compound used by this invention has a structure represented by following General formula (1)-(4).

R < ₁ > -R < ₅ > in General formula (1), (2) and (4) represents a substituent each independently. Although there is no restriction | limiting in particular as a substituent, It is preferable that it is a substituent contained in the following compound.

Specific compounds include 6- (dibutylamino) -1,3,5-triazine-2,4-dithiol, thiocyanuric acid, 1-phenyl-5-mercapto-1H-tetrazole, bismuthiol, 2-mercaptopyrimidine, 2-mercaptobenzothiazole, 1,3-diethyl-2-thiourea, 1,3-diphenyl-2-thiourea, mercaptobenzimidazole, cysteine, 2-aminothiazole, 2-amino-1,3,4-thiadiazole , Methionine, 2-amino-5-mercapto-1,3,4-thiadiazole, 2-aminobenzenethiol, L-cysteine methyl hydrochloride, L-cysteine ethyl hydrochloride, 2-aminoethanethiol, thiomorpholine, 1- Thioglycerol, N-acetyl-L-cysteine, dimethyl sulfide 3-mercapto-1,2,4-triazole, butanediol bisthioglycolate, 1,10-dimercaptodecane (1,10-decanediol), pentaerythritol tetrakisthioglycolate, 1,4-bis (3- Mercaptobutyryloxy) butane, 1,3,5-tris (3-mercaptobutyryloxyethyl) -1,3,5-triazine-2,4,6 (1H, 3H, 5H) -trione, etc. are used. You can, but you are not limited to these.
Moreover, it is preferable that the content density | concentration of a sulfur containing compound exists in the range of 1-15 mass% with respect to the total mass of a thermochromic film from a viewpoint from which a thermochromic film acquires favorable thermochromic property.
In the present invention, two or more sulfur-containing compounds may be used in combination.

[Metal-containing surface modifier]
The thermochromic film of the present invention is characterized by containing a metal-containing surface modifier.
The metal-containing surface modifier according to the present invention preferably contains a metal complex, and more preferably contains a metal alkoxide compound. For example, titanate alkoxide compounds, titanate coupling agents, silane alkoxide compounds, silane coupling agents, aluminate alkoxide compounds, aluminate coupling agents, zirconate alkoxide compounds, zirconate coupling agents can be used. It is not limited.
More specifically, the metal-containing surface modifier according to the present invention preferably has a structure represented by the following general formulas (5) to (7).
The compound having the structure represented by the following general formulas (5) to (7) is not particularly limited as long as it has an effect of improving the wet heat resistance of vanadium dioxide. It is thought that the functional group accompanying these metals hydrolyzes and dehydrates and condenses with vanadium, thereby forming a chemical bond with vanadium and improving the heat and moisture resistance.

In general formulas (5) to (7), the substituent represented by R _{6 to} R ₁₇ is not particularly limited, but is included in a chelate ligand that forms a chelate complex coordinated to each central metal. It is also preferable that
Chelating ligands include EDTA (ethylenediaminetetraacetic acid), EDA (ethylenediamine), BAPTA (1,2-bis (o-aminophenoxide) ethane-N, N, N ′, N′-tetraacetic acid) and crown ether (12-crown-4, 15-crown-5, 18-crown-6, dibenzo-18-crown-6, diaza-18-crown-6), triethanolamine, etc. can be used, but are not limited thereto. Not what you want.
Examples of the product name include, but are not limited to, the Orugatix series (manufactured by Matsumoto Fine Chemical Co., Ltd.), Plenact (manufactured by Ajinomoto Fine Techno Co., Ltd.), and the aluminum organic compound (manufactured by Kawaken Fine Chemical Co., Ltd.).
In the present invention, two or more metal-containing surface modifiers may be used in combination.

〔binder〕
The optical functional film according to the present invention is characterized by containing a binder. The binder may be an organic solvent binder or an aqueous binder.

[Organic solvent binder]
As the organic solvent-based binder used in the present invention, various resins that can be dissolved in a solvent can be used, but thermosetting resins and active energy ray-curable resins can also be used. These resins can be used alone or in combination of two or more. Moreover, a commercial item may be used and a synthetic item may be used.
The active energy ray-curable resin is a resin that is cured through a crosslinking reaction or the like by irradiation with active energy rays such as ultraviolet rays or electron beams. As the active energy ray curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active energy ray curable resin layer is cured by irradiation with an active energy ray such as an ultraviolet ray or an electron beam. Is formed. Typical examples of the active energy ray curable resin include an ultraviolet curable resin, an electron beam curable resin, and the like, and an ultraviolet curable resin that is cured by ultraviolet irradiation is preferable.

As the ultraviolet curable resin, for example, an ultraviolet curable urethane acrylate resin is preferably used. Of these, ultraviolet curable acrylate resins are preferred.
UV-curable acrylic urethane resins generally include 2-hydroxyethyl acrylate and 2-hydroxyethyl methacrylate (hereinafter referred to as acrylates) in addition to products obtained by reacting polyester polyols with isocyanate monomers or prepolymers. Only acrylate is indicated as the product), and it can be easily obtained by reacting an acrylate monomer having a hydroxy group such as 2-hydroxypropyl acrylate. For example, a mixture of 100 parts of Unidic 17-806 (manufactured by DIC Corporation) and 1 part of Coronate L (manufactured by Tosoh Corporation) described in JP-A-59-151110 is preferably used.

(Water-based binder)
As the water-based binder used in the present invention, various resins that are soluble in water can be used. For example, low molecular weight compounds such as alkyl sulfonates, alkyl benzene sulfonates, diethyl amines, ethylene diamines, and quaternary ammonium salts. In addition to these dispersants, there may be mentioned polyoxyethylene nonylphenyl ether, polyoxyethylene lauric acid ether, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyethylene glycol, hydroxyethyl cellulose, silane coupling agents, etc. Preferably there is.

〔Base material〕
The base material (transparent base material) applicable to the present invention is not particularly limited as long as it is transparent, and examples thereof include glass, quartz, and a transparent resin film. From the viewpoint of process suitability, it is preferably a transparent resin film. “Transparent” in the present invention means that the average light transmittance in the visible light region is 50% or more, preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.
The thickness of the transparent substrate is preferably in the range of 30 to 200 μm, more preferably in the range of 30 to 100 μm, and still more preferably in the range of 35 to 70 μm. If the thickness of the transparent substrate is 30 μm or more, wrinkles and the like are less likely to occur during handling, and if the thickness is 200 μm or less, for example, when producing a laminated glass, Followability to the curved glass surface is improved.
The transparent substrate is preferably a biaxially oriented polyester film, but an unstretched or at least one stretched polyester film can also be used. A stretched film is preferable from the viewpoint of strength improvement and thermal expansion suppression. In particular, when the laminated glass provided with the thermochromic film of the present invention is used as an automobile windshield, a stretched film is more preferable.

The transparent substrate preferably has a thermal shrinkage within a range of 0.1 to 3.0% at a temperature of 150 ° C. from the viewpoint of preventing wrinkles and cracking of the thermochromic film. More preferably, it is within the range of 3.0%, and even more preferably within the range of 1.9 to 2.7%.
The transparent substrate applicable to the thermochromic film of the present invention is not particularly limited as long as it is transparent, but various resin films are preferably used. For example, polyolefin films (for example, polyethylene, polypropylene, etc.) ), Polyester films (for example, polyethylene terephthalate, polyethylene naphthalate, etc.), polyvinyl chloride, triacetyl cellulose films, and the like, preferably polyester films and triacetyl cellulose films.

Although it does not specifically limit as a polyester film (henceforth only polyester), It is preferable that it is polyester which has the film formation property which has a dicarboxylic acid component and a diol component as main structural components.
The main constituent dicarboxylic acid components include terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, diphenylsulfone dicarboxylic acid, diphenyl ether dicarboxylic acid, diphenylethanedicarboxylic acid, Examples thereof include cyclohexane dicarboxylic acid, diphenyl dicarboxylic acid, diphenyl thioether dicarboxylic acid, diphenyl ketone dicarboxylic acid, and phenylindane dicarboxylic acid. Examples of the diol component include ethylene glycol, propylene glycol, tetramethylene glycol, cyclohexanedimethanol, 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxyethoxyphenyl) propane, bis ( 4-Hydroxyphenyl) sulfone, bisphenol fluorene hydroxyethyl ether, diethylene glycol, neopentyl glycol, hydroquinone, cyclohexanediol and the like.

  Among the polyesters having these as main constituent components, from the viewpoint of transparency, mechanical strength, dimensional stability, etc., dicarboxylic acid components such as terephthalic acid, 2,6-naphthalenedicarboxylic acid, diol components such as ethylene glycol and 1 Polyester having 1,4-cyclohexanedimethanol as the main constituent is preferred. Among these, polyesters mainly composed of polyethylene terephthalate and polyethylene naphthalate, copolymerized polyesters composed of terephthalic acid, 2,6-naphthalenedicarboxylic acid and ethylene glycol, and mixtures of two or more of these polyesters are mainly used. Polyester as a constituent component is preferable.

  When a transparent resin film is used as the transparent substrate, particles may be contained within a range that does not impair transparency in order to facilitate handling. Examples of particles used in the present invention include inorganic particles such as calcium carbonate, calcium phosphate, silica, kaolin, talc, titanium dioxide, alumina, barium sulfate, calcium fluoride, lithium fluoride, zeolite, molybdenum sulfide, and crosslinked polymers. Examples thereof include organic particles such as particles and calcium oxalate. Examples of the method of adding particles include a method of adding particles in a polyester as a raw material, a method of adding directly to an extruder, and the like. Well, you may use two methods together. In the present invention, additives may be added in addition to the above particles as necessary. Examples of such additives include stabilizers, lubricants, cross-linking agents, anti-blocking agents, antioxidants, dyes, pigments, and ultraviolet absorbers.

In addition, the transparent resin film may be subjected to relaxation treatment or off-line heat treatment in terms of dimensional stability. The relaxation treatment is preferably carried out in the process from the heat setting in the stretching process of the polyester film to the winding in the transversely stretched tenter or after exiting the tenter. The relaxation treatment is preferably performed at a treatment temperature in the range of 80 to 200 ° C, and more preferably at a treatment temperature in the range of 100 to 180 ° C. Moreover, it is preferable that the relaxation rate is within a range of 0.1 to 10% in both the longitudinal direction and the width direction, and more preferably, the relaxation rate is within a range of 2 to 6%. The relaxed substrate is subjected to off-line heat treatment to improve heat resistance and to improve dimensional stability.
The transparent resin film is preferably coated with the undercoat layer coating solution in-line on one or both sides during the film formation process. In the present invention, undercoating during the film forming process is referred to as in-line undercoating.

(Near-infrared light shielding layer)
In the thermochromic film of the present invention, when a layer containing vanadium dioxide particles is provided as an optical functional film, a near infrared light shielding function having a function of shielding at least a part of a light wavelength range within a range of 700 to 1000 nm. A structure in which a layer is further provided may be employed.
For details of the near infrared light shielding layer applicable to the present invention, for example, JP 2012-131130 A, JP 2012-139948 A, JP 2012-185342 A, JP 2013-080178 A. The constituent elements and forming methods described in JP-A-2014-089347 and the like can be referred to.

[Other additives]
Various additives that can be applied to the thermochromic film of the present invention as long as the effects of the present invention are not impaired are listed below. For example, ultraviolet absorbers described in JP-A-57-74193, JP-A-57-87988, and JP-A-62-261476, JP-A-57-74192, JP-A-57- No. 878989, JP-A-60-72785, JP-A-61-146591, JP-A-1-95091, JP-A-3-13376 and the like, an anion, Various surfactants of cation or nonion, JP-A-59-42993, JP-A-59-52689, JP-A-62-280069, JP-A-61-242871, and JP-A-4-242 209266, etc., optical brighteners, sulfuric acid, phosphoric acid, acetic acid, citric acid, sodium hydroxide, potassium hydroxide, potassium carbonate and other pH adjusters, antifoaming agents Lubricants such as diethylene glycol, antiseptics, antifungal agents, antistatic agents, matting agents, heat stabilizers, antioxidants, flame retardants, crystal nucleating agents, inorganic particles, organic particles, viscosity reducing agents, lubricants, infrared absorbers And various known additives such as dyes and pigments.

(Method for producing aqueous dispersion of vanadium dioxide particles)
In general, synthesis of vanadium dioxide particles, a method of pulverizing the VO ₂ sintered body synthesized by the solid phase method, vanadium pentoxide and (V 2 _{O 5)} as a starting material to synthesize the VO ₂ in the liquid phase An aqueous synthesis method in which particles are grown is mentioned.

In the present invention, VO ₂ produced by any method can be applied. A dispersant is added to VO ₂ produced by any method, and a dispersion is prepared in an aqueous or organic solvent system.
It is preferable that the addition amount of a dispersing agent exists in the range of 0.1-1.0 mass%.
In the case of water-based dispersants, in addition to low molecular weight dispersants such as alkyl sulfonates, alkyl benzene sulfonates, diethylamine, ethylenediamine, quaternary ammonium salts, polyoxyethylene nonylphenyl ether, polyexethylene lauryl Examples include acid ether, hydroxyethyl cellulose, polyvinyl pyrrolidone, polyethylene glycol, hydroxyethyl cellulose, and silane coupling agents, and polyvinyl pyrrolidone or cellulose resin is particularly preferable.

  As the organic solvent-based dispersant, commonly used organic dispersants such as alkylamines, silane coupling agents, and phosphoric acid-based dispersants can be used.
  If these dispersants are used, VO in the dispersion₂A coating solution for forming a thermochromic film can be prepared without drying the particles. Furthermore, when the thermochromic film of this invention is formed on a board | substrate, it can also prepare as a coating liquid for optical function film | membrane formation as described in an Example.
  By forming a thermochromic film (optical functional film) using the coating solution in this state, the number average particle diameter of primary particles and secondary particles is less than 500 nm.₂A thermochromic film (optical functional film) containing particles can be formed.
  VO₂As a method for producing particles, if necessary, fine TiO as the core of particle growth ₂And so on as a core particle, and by growing the core particle, VO₂Particles can also be produced.
  In addition, when using a water-soluble resin binder as a resin binder, the above-mentioned VO₂After preparing as an aqueous dispersion containing particles, VO in the aqueous dispersion₂VO without drying the particles₂It is preferable to prepare a coating solution by mixing with a water-soluble resin binder solution in a dispersed state in which the particles are separated.

[Method for forming thermochromic film]
The manufacturing method of the thermochromic film of this invention has the process of forming the optical function film | membrane containing the vanadium dioxide particle which shows the thermochromic property synthesize | combined by the hydrothermal reaction, It is characterized by the above-mentioned.
It is preferable to use a wet coating method for forming the thermochromic film, and is not particularly limited. For example, a roll coating method, a rod bar coating method, an air knife coating method, a spray coating method, a slide curtain coating method, or a US patent Examples thereof include a slide hopper coating method and an extrusion coating method described in US Pat. No. 2,761,419 and US Pat. No. 2,761791.
Then, the present invention in a suitable hydrothermal reaction (hereinafter also referred to as hydrothermal synthesis.) A method for manufacturing the VO ₂ particles by, for explaining an example of the details.

  (Process 1)
  Substance (I) containing vanadium (V) and hydrazine (N₂H₄) Or its hydrate (N₂H₄・ NH₂O) and water are mixed to prepare a solution (A). The solution (A) may be an aqueous solution in which the substance (I) is dissolved in water, or may be a suspension in which the substance (I) is dispersed in water.
  Examples of the substance (I) include divanadium pentoxide (V₂O₅), Ammonium vanadate (NH₄VO₃), Vanadium trichloride oxide (VOCl)₃), Sodium metavanadate (NaVO)₃) And the like. The substance (I) is not particularly limited as long as it is a compound containing pentavalent vanadium (V). Hydrazine (N₂H₄) And its hydrates (N ₂H₄・ NH₂O) functions as a reducing agent for the substance (I) and has a property of being easily dissolved in water.

The solution (A) may further contain a substance (II) containing the element to be added in order to add the element to the finally obtained vanadium dioxide (VO ₂ ) single crystal particles. Examples of the element to be added include tungsten (W), molybdenum (Mo), niobium (Nb), tantalum (Ta), tin (Sn), rhenium (Re), iridium (Ir), osmium (Os), ruthenium ( Ru), germanium (Ge), chromium (Cr), iron (Fe), gallium (Ga), aluminum (Al), fluorine (F), or phosphorus (P).
By adding these elements to the finally obtained vanadium dioxide (VO ₂ ) single crystal particles, the thermochromic properties of the vanadium dioxide particles, in particular, the transition temperature can be controlled.

Moreover, this solution (A) may further contain a substance (III) having oxidizing property or reducing property. Examples of the substance (III) include hydrogen peroxide (H ₂ O ₂ ). By adding the oxidizing or reducing substance (III), the pH of the solution can be adjusted, or the substance containing vanadium (V) as the substance (I) can be uniformly dissolved.

(Process 2)
Next, a hydrothermal reaction treatment is performed using the prepared solution (A). Here, “hydrothermal reaction” means a chemical reaction that occurs in hot water (subcritical water) whose temperature and pressure are lower than the critical point of water (374 ° C., 22 MPa). The hydrothermal reaction treatment is performed, for example, in an autoclave apparatus. By the hydrothermal reaction treatment, single crystal particles containing vanadium dioxide (VO ₂ ) are obtained.
The conditions of the hydrothermal reaction treatment (for example, the amount of reactants, the treatment temperature, the treatment pressure, the treatment time, etc.) are set as appropriate, but the temperature of the hydrothermal reaction treatment is, for example, within the range of 250 to 350 ° C. Preferably, it exists in the range of 250-300 degreeC, More preferably, it exists in the range of 250-280 degreeC. By reducing the temperature, the particle diameter of the obtained single crystal particles can be reduced, but if the particle diameter is excessively small, the crystallinity is lowered. Moreover, it is preferable that the time of a hydrothermal reaction process exists in the range of 1 hour-5 days, for example. By increasing the time, the particle diameter and the like of the obtained single crystal particles can be controlled. However, if the processing time is excessively long, the energy consumption increases.

(Process 3)
If necessary, the surface of the obtained vanadium dioxide particles may be subjected to a coating treatment or a surface modification treatment with a resin. Thereby, the surface of the vanadium dioxide particles is protected, and surface-modified single crystal particles can be obtained.
The “coating” referred to in the present invention may be a state where the entire surface of the particle is completely covered with the resin with respect to the vanadium dioxide particles, or a part of the particle surface is covered with the resin. It may be in a state. Preferably, a state where 50% or more of the total area of the particle surface is covered is good, and a state where 80% or more is covered is more preferable.
Through the above steps 1 to 3, a dispersion liquid containing VO ₂ -containing single crystal particles having thermochromic properties is obtained.

[VO ₂ grinding method]
There are various methods for making VO ₂ into fine particles, such as bead milling, ultrasonic crushing, and high-pressure homogenizer, and any method can be used to produce VO ₂ particles.
Various beads can be used in the bead mill, but zirconia beads are preferably used from the viewpoint of hardness and price.

[Removal of impurities in aqueous dispersion of vanadium dioxide particles]
Impurities such as residues generated in the synthesis process are contained in the dispersion of vanadium dioxide particles prepared by the aqueous synthesis method. When forming a thermochromic film (optical functional film), these impurities cause secondary aggregated particles, which may cause deterioration of the thermochromic film (optical functional film) during long-term storage. It is preferable to remove impurities at the liquid stage.
As a method for removing impurities in the aqueous dispersion of vanadium dioxide particles, conventionally known means for separating foreign substances and impurities can be applied. For example, the VO ₂ particle aqueous dispersion is subjected to centrifugal separation to obtain vanadium dioxide particles. It is possible to remove the impurities in the supernatant, add and disperse the dispersion medium again, or remove the impurities out of the system using an exchange membrane such as an ultrafiltration membrane. From the viewpoint of preventing aggregation of particles, a method using an ultrafiltration membrane is most preferable.
Examples of the material for the ultrafiltration membrane include cellulose, polyethersulfone, and polytetrafluoroethylene (abbreviation: PTFE). Among these, polyethersulfone and PTFE are preferably used.

<Thermochromic laminate>
As a use of the thermochromic film of this invention, it can be used as a thermochromic laminated body provided with the thermochromic film as a component. For example, when a thermochromic film is laminated on a substrate such as glass or the like, laminated glass can be formed by being sandwiched between a pair of glass constituent members. This laminated glass can be used for automobiles, railway vehicles, aircraft, ships, buildings, and the like. Laminated glass can be used for other purposes. The laminated glass is preferably laminated glass for buildings or vehicles. The laminated glass can be used for an automobile windshield, side glass, rear glass, roof glass, or the like.
As the substrate of the thermochromic laminate, the base material of the thermochromic film can be used similarly.

Examples of the glass substrate include inorganic glass and organic glass (resin glazing). Examples of the inorganic glass include colored glass such as float plate glass, heat ray absorbing plate glass, polished plate glass, mold plate glass, netted plate glass, lined plate glass, and green glass. The organic glass is a synthetic resin glass substituted for inorganic glass. Examples of the organic glass (resin glazing) include a polycarbonate plate and a poly (meth) acrylic resin plate. Examples of the poly (meth) acrylic resin plate include a polymethyl (meth) acrylate plate. In the present invention, inorganic glass is preferred from the viewpoint of safety when it is damaged by an external impact.
Moreover, it can apply besides glass, The laminated body comprised from the support body of the whole thermochromic film containing glass and a thermochromic film can also be made into a thermochromic laminated body.

  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, "mass part" or "mass%" is represented. In the table, “film” represents a thermochromic film, and “laminate” represents a thermochromic laminate. Table 1 shows the raw materials used for the production of each film, their concentrations, base materials and the like. Table 2 shows the results of physical properties evaluation (color tone change, frame evaluation, transmittance and transmittance change) of the produced thermochromic laminate.

《Preparation of thermochromic film》
[Preparation of Thermochromic Film 1: Present Invention]
(Preparation of VO ₂ particle aqueous dispersion 1)
Mixing 74.9 g of vanadium dioxide particles (VO ₂ , manufactured by Shinsei Chemical Co., Ltd.) with 425 mL of pure water, using 200 g of 300 μm zirconia beads for a bead mill, and using an Apex mill (Hiroshima Metal & Machinery Co., Ltd.) went. Ammonia water was added to the pulverized particles so that the standard oxidation-reduction potential was 330 mV and the pH at 25 ° C. was 6.5 to prepare a vanadium dioxide particle aqueous dispersion.

(Preparation of coating solution 1 for forming an optical functional film)
The following constituent materials were mixed so as to have the following ratio, and finally, water was used as a solvent to prepare a solid content of 4% by mass.
· VO ₂ particle aqueous dispersion: VO ₂ weight (solvent water): 13 wt%
-Polyvinylpyrrolidone / vinyl acetate copolymer S-630 (manufactured by IPS Japan Ltd.): 76% by mass
・ Cysteine (Peptide Institute): 0.5% by mass
・ Orgachics TC-400 (manufactured by Matsumoto Fine Chemical Co., titanate coupling agent): 10% by mass

(Formation of optical functional film)
Using an extrusion coater on a transparent substrate of a polyethylene terephthalate film (Toray U40, double-sided easy-adhesion layer) having a thickness of 50 μm, the layer thickness after drying of the coating solution 1 for forming an optical functional film prepared above is used. Wet application was performed under the condition of 1.5 μm, and then 90 ° C. warm air was blown for 1 minute to dry to form an optical functional film, thereby producing a thermochromic film 1 having the configuration shown in FIG. .

[Preparation of Thermochromic Film 2: Present Invention]
Thermochromic film 2 was prepared in the same manner as in the preparation of thermochromic film 1, except that the concentration of cysteine was 1.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 3: Present Invention]
The thermochromic film 3 was produced in the same manner as in the production of the thermochromic film 1 except that the concentration of cysteine was 5.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 4: Present Invention]
In producing the thermochromic film 3, a thermochromic film 4 was produced in the same manner except that KBE-903 (manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of TC-400.

[Preparation of Thermochromic Film 5: Present Invention]
The thermochromic film 5 was produced in the same manner as in the production of the thermochromic film 1 except that the concentration of cysteine was 15.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 6: Present Invention]
The thermochromic film 6 was produced in the same manner as in the production of the thermochromic film 1 except that the concentration of cysteine was changed to 17.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 7: Present Invention]
In preparation of the thermochromic film 3, the solvent of the dispersion liquid containing VO ₂ particles was changed to an organic solvent system prepared as follows.

(Preparation of VO ₂ particle organic solvent dispersion)
74.9 g of vanadium dioxide particles (VO ₂ , manufactured by Shinsei Chemical Co., Ltd.) are mixed with 425 mL of methyl isobutyl ketone, 30.0 g of a dispersing agent BYK-399 (manufactured by Big Chemie), and trioctylamine (manufactured by Wako Pure Chemical Industries) 45 0.0 g was added, 200 g of 30 μm zirconia beads for bead mill were used, and pulverization was performed using Apex mill (manufactured by Hiroshima Metal & Machinery Co., Ltd.) to prepare an organic solvent dispersion of vanadium dioxide particles.

(Preparation of coating solution 2 for forming an optical functional film)
The following constituent materials were mixed so as to have the following ratio, and finally, methyl isobutyl ketone was used as a solvent to prepare a solid content of 10% by mass.
· VO ₂ VO ₂ of the particles an organic solvent-based dispersion: 13 wt%
・ Aronix M-305 (Toagosei Co., Ltd.): 73% by mass
・ Irgacure 184 (manufactured by BASF): 3% by mass
-Surflon S-242 (manufactured by AGC Seimi Chemical Co.): 0.1% by mass
・ Cysteamine (manufactured by Tokyo Chemical Industry Co., Ltd.): 5% by mass
-Orgachics TC-400 (Matsumoto Fine Chemical Co., Ltd.): 10% by mass

(Formation of optical functional film)
On the transparent base material of a polyethylene terephthalate film (Toray U40, double-sided easy-adhesion layer) having a thickness of 50 μm, the coating film 2 for forming an optical functional film prepared above using an extrusion coater has a film thickness after drying. Wet application was performed under the condition of 1.5 μm, and then 90 ° C. warm air was blown for 30 seconds to dry to form an optical functional film, thereby producing a thermochromic film 7 having the configuration shown in FIG. .

[Preparation of Thermochromic Film 8: Present Invention]
Thermochromic film 8 was prepared in the same manner except that KBE-903 was used instead of TC-400 in preparation of thermochromic film 7.

[Preparation of Thermochromic Film 9: Present Invention]
In producing the thermochromic film 7, a thermochromic film 9 was produced in the same manner except that TA-8 (manufactured by Matsumoto Fine Chemical Co., titanate alkoxide compound) was used instead of TC-400.

[Preparation of Thermochromic Film 10: Present Invention]
The thermochromic film 10 was produced in the same manner as in the production of the thermochromic film 7 except that the concentration of cysteamine was 10.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 11: Present Invention]
In the production of the thermochromic film 7, 3-mercapto-1,2,4-triazole was used in place of cysteamine, and the addition was made so as to be 0.1% by mass with respect to the total mass in the coating film. Thus, a thermochromic film 11 was produced.

[Preparation of Thermochromic Film 12: Present Invention]
A thermochromic film 12 was produced in the same manner as in the production of the thermochromic film 11 except that the concentration of 3-mercapto-1,2,4-triazole was 5.0% by mass.

[Preparation of Thermochromic Film 13: Present Invention]
In producing the thermochromic film 12, a thermochromic film 13 was produced in the same manner except that Plenact 44 (manufactured by Ajinomoto Fine Techno Co., Ltd., aluminate coupling agent) was used instead of TC-400.

[Preparation of Thermochromic Film 14: Present Invention]
A thermochromic film 14 was prepared in the same manner as in the preparation of the thermochromic film 10 except that 3-mercapto-1,2,4-triazole was used instead of cysteamine.

[Preparation of Thermochromic Film 15: Present Invention]
In producing the thermochromic film 11, a thermochromic film 15 was produced in the same manner except that 2-aminothiazole (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of 3-mercapto-1,2,4-triazole. .

[Preparation of Thermochromic Film 16: Present Invention]
The thermochromic film 16 was produced in the same manner as in the production of the thermochromic film 15 except that the concentration of 2-aminothiazole was 5.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 17: Present Invention]
In producing the thermochromic film 16, a thermochromic film 17 was produced in the same manner except that KBE-903 (manufactured by Shin-Etsu Chemical Co., Ltd., silane coupling agent) was used instead of TC-400.

[Preparation of Thermochromic Film 18: Present Invention]
In the production of the thermochromic film 16, a thermochromic film 18 was produced in the same manner except that the concentration of 2-aminothiazole was 10.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 19: Present Invention]
A thermochromic film 19 was produced in the same manner as in the production of the thermochromic film 14 except that 2-aminothiazole was used instead of 3-mercapto-1,2,4-triazole.

[Preparation of Thermochromic Film 20: Present Invention]
In the production of the thermochromic film 18, a thermochromic film 20 was produced in the same manner except that the concentration of 2-aminothiazole was changed to 17.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 21: Present Invention]
A thermochromic film 21 was produced in the same manner as in the production of the thermochromic film 3 except that 1-thioglycerol (manufactured by Asahi Chemical Industry Co., Ltd.) was used instead of cysteine.

[Preparation of Thermochromic Film 22: Present Invention]
A thermochromic film 22 was produced in the same manner as in the production of the thermochromic film 21, except that the concentration of 1-thioglycerol was 10.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 23: Present Invention]
In the production of the thermochromic film 12, a thermochromic film 23 was produced in the same manner except that dimethyl sulfide (manufactured by Wako Pure Chemical Industries, Ltd.) was used instead of 3-mercapto-1,2,4-triazole.

[Preparation of Thermochromic Film 24: Present Invention]
In the production of the thermochromic film 23, a thermochromic film 24 was produced in the same manner except that the concentration of dimethyl sulfide was 10.0% by mass with respect to the total mass in the coating film.

[Preparation of Thermochromic Film 25: Present Invention]
In the production of the thermochromic film 19, the thermochromic was similarly performed except that the concentration of 2-aminothiazole was 5.0% by mass with respect to the total mass in the coating film and the film was formed on glass instead of the PET film. Film 25 was produced.

[Preparation of Thermochromic Film 26: Present Invention]
In preparation of the thermochromic film 19, butanediol bisthioglycolate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 2-aminothiazole, and the concentration was 10.0% by mass with respect to the total mass in the coating film. . Also, instead of ORGATICS TC-400, ORGATICS TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) was used, and the concentration was adjusted to 20.0% by mass with respect to the total mass in the coating film. Other than that produced the thermochromic film 26 similarly.

[Preparation of Thermochromic Film 27: Present Invention]
In the production of the thermochromic film 26, the concentration of butanediol bisthioglycolate was 15.0% by mass with respect to the total mass in the coating film, and the thermochromic film 27 was produced in the same manner except that.

[Preparation of Thermochromic Film 28: Present Invention]
In the production of the thermochromic film 26, the concentration of aluminum chelate ALCH (manufactured by Kawaken Fine Chemical Co., Ltd.) is set to 20.0% by mass with respect to the total mass in the coating film instead of ORGATICS TC-750. Thus, a thermochromic film 28 was produced.

[Preparation of Thermochromic Film 29: Present Invention]
A thermochromic film 29 was produced in the same manner as in the production of the thermochromic film 26 except that 1,10-dimercaptodecane was used instead of butanediol bisthioglycolate.

[Preparation of Thermochromic Film 30: Present Invention]
A thermochromic film 30 was produced in the same manner as in the production of the thermochromic film 27 except that 1,10-dimercaptodecane was used instead of butanediol bisthioglycolate.

[Preparation of Thermochromic Film 31: Present Invention]
A thermochromic film 31 was produced in the same manner as in the production of the thermochromic film 28 except that 1,10-dimercaptodecane was used instead of butanediol bisthioglycolate.

[Preparation of Thermochromic Film 32: Comparative Example]
In producing the thermochromic film 1, a thermochromic film 32 was produced in the same manner except that cysteine and TC-400 were not added.

[Preparation of Thermochromic Film 33: Comparative Example]
In the production of the thermochromic film 1, a thermochromic film 33 was produced in the same manner except that cysteine was not added.

[Preparation of Thermochromic Film 34: Comparative Example]
In the production of the thermochromic film 32, the concentration of tryptophan (manufactured by Wako Pure Chemical Industries, Ltd.) was added so as to be 10.0% by mass with respect to the total mass in the coating film, and the thermochromic was otherwise performed in the same manner. A film 34 was produced.

[Preparation of Thermochromic Film 35: Comparative Example]
In the production of the thermochromic film 3, a thermochromic film 35 was produced in the same manner except that TC-400 was not added.

[Preparation of Thermochromic Film 36: Comparative Example]
In the production of the thermochromic film 7, a thermochromic film 36 was produced in the same manner except that cysteamine or TC-400 was not added.

<< Production of thermochromic laminate >>
Each of the thermochromic films prepared above is a transparent adhesive sheet (manufactured by Nitto Denko Corporation, LUCIACS CS9621T) on a glass plate having a thickness of 1.3 mm and a size of 15 cm × 20 cm (manufactured by Matsunami Glass Industrial Co., Ltd., “Slide Glass White Edge Polish”). The thermochromic laminate was prepared by using each thermochromic film prepared as described above.

<Evaluation of spectral transmittance>
Using a spectrophotometer V-670 (manufactured by JASCO Corporation), the spectrum of each prepared thermochromic laminate was measured from 250 to 2500 nm. The change in thermochromic properties was confirmed from the transmittance at a wavelength of 1500 nm at 75 ° C. (high temperature) using a transmittance at a wavelength of 1500 nm at 25 ° C. (room temperature) and a heating measuring device.
Furthermore, the transmittance at a wavelength of 1500 nm at 25 ° C. and a wavelength of 1500 nm at 75 ° C. was measured, and the obtained change width of thermochromic property and 85 ° C./85% RH, at 25 ° C. before and after the durability test of 500 hours. The transmittance at a wavelength of 1500 nm and a wavelength of 1500 nm at 75 ° C. was measured, and the obtained thermochromic change width was also confirmed.

《Thermochromic durability (wet heat resistance)》
Each thermochromic laminate was allowed to stand for 500 hours in an environment of 85 ° C. and 85% RH. And about each thermochromic laminated body after 500-hour progress, the spectrum to 250-2500 nm is similarly measured using the spectrophotometer V-670 (made by JASCO Corporation), and the discoloration degree which is the change width of a color tone ΔE (the following formula) was measured. The color change degree ΔE is a CIE Lab color system represented by lightness L ^* and a color space value a ^* and b ^* . L ^* = 0 is represented by black, L ^* = 100 is represented by white, a ^* represents the position of red and green (negative value is green, positive value is red), and b ^* is the position of yellow and blue ( Negative values correspond to blue and positive values to yellow).
ΔE = [(ΔL ^* ) ² + (Δa ^* ) ² + (Δb ^* ) ² ] ^1/2

<< frame evaluation >>
The appearance of the sample that was allowed to stand for 500 hours in an environment of 85 ° C. and 85% RH was confirmed, and the following evaluation was performed. In addition, the edge part of a film points out the part around it with respect to the center part of a film, and points out the area | region within 1 cm from an edge part. O: The color change in the edge part of a film A state in which the image does not occur Δ: A state in which the color is not changed in part or slightly in the edge portion of the film ×: A state in which the color is clearly changed in the edge portion of the film

<Evaluation results>
As can be seen from the results in Table 2, when the thermochromic film of the present invention was evaluated by the transmittance at a wavelength of 1500 nm, it was 25 ° C. (room temperature) and 75 in each of the conditions before and after standing for 500 hours in an 85 ° C./85% RH environment. It was found that there was a large difference in transmittance at ° C. (high temperature) and an excellent thermochromic property.

In addition, as can be seen from the results of evaluation after the thermochromic film of the present invention was allowed to stand for 500 hours in an environment of 85 ° C. and 85% RH, even after standing for 500 hours in a high-temperature and high-humidity environment, It was found that the difference in transmittance (%) between room temperature and 75 ° C. (high temperature) remained large, and it had excellent durability (wet heat resistance).
In addition, when the thermochromic film which peeled the PET base material of the thermochromic film 19 was produced and evaluated, it turned out that the same physical-property value as the thermochromic film 19 is shown.

It can be seen that the change width of the difference between the room temperature and the high temperature of the example is small, and the change width is large in the comparative example. In the examples, the thermochromic film 11 having the largest variation is 3.6%, whereas the thermochromic film 35 is 5.9%, and the thermochromic film of the present invention is clearly superior in the wet heat test. I found out.
In contrast, the thermochromic film 20 (invention) has a particularly high transmittance (%) at a high temperature of 75 ° C. (high temperature), and a transmittance (%) at 25 ° C. (room temperature) and 75 ° C. (high temperature). It turned out that the difference of became small.

It can be seen that the change width of ΔE is small when the compound according to the present invention is used. The tryptophan in the comparative example has a large ΔE movement and was found to be involved in coloring.
Even in the frame evaluation, it was shown that the frame is hardly generated in the thermochromic laminate of the present invention.

  From the above results, by using the method described in the present invention, a thermochromic film containing vanadium dioxide particles, which exhibits excellent thermochromic properties and excellent durability, and a thermochromic laminate including the same as a constituent element It was confirmed that the body was made.

  The optical functional film of the present invention is excellent in thermochromic properties and durability, and can be suitably used for thermochromic films.

1 Thermochromic film 2 Transparent base material (base material)
3 Optical functional film B1 Resin binder VO _S primary particle VO _M secondary particle

Claims (12)

An optical functional film containing vanadium dioxide particles exhibiting thermochromic properties,
An optical functional film comprising the vanadium dioxide particles, a sulfur-containing compound, a metal-containing surface modifier, and a binder.   A thermochromic film, wherein the optical functional film according to claim 1 is provided on a substrate.   The thermochromic film according to claim 2, wherein the sulfur-containing compound contains a thiol.   The thermochromic film according to claim 2, wherein the sulfur-containing compound contains a sulfur-containing primary amine.   The thermochromic film according to any one of claims 2 to 4, wherein the metal-containing surface modifier contains a metal complex.   The thermochromic film according to any one of claims 2 to 5, wherein a metal alkoxide compound is contained as the metal-containing surface modifier.   The thermochromic film according to any one of claims 2 to 6, wherein the metal-containing surface modifier contains a titanate alkoxide compound.   The thermochromic film according to any one of claims 2 to 7, wherein cysteine is contained as the sulfur-containing compound.   The thermochromic film according to any one of claims 2 to 8, wherein 2-aminothiazole is contained as the sulfur-containing compound.   The content concentration of the sulfur-containing compound is within a range of 1 to 15% by mass with respect to the total mass of the thermochromic film, according to any one of claims 2 to 9. Thermochromic film.   A thermochromic laminate, wherein the thermochromic film according to any one of claims 2 to 10 is provided on a substrate.   It is a manufacturing method of the thermochromic film which manufactures the thermochromic film as described in any one of Claim 2 to 10, Comprising: The vanadium dioxide particle which shows the thermochromic property synthesize | combined by the hydrothermal reaction is contained. A method for producing a thermochromic film, comprising a step of forming an optical functional film.

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