JP7299574B2 - Coating liquid, cured film, and laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to powders, coating liquids, cured films, and laminates.

Mechanochromism is a phenomenon in which solid-state luminescent organic molecules change their luminescent color by mechanical stimulation, and return to the original luminescent color by exposure to heat or solvent vapor.

An object of the invention described in Patent Document 1 is to provide a mechanochromic luminescent material that can quickly or simply return to the original luminescent color and has multicolor luminescent properties. This document describes a compound obtained by introducing a triethylene glycol monomethyl ether chain or a diethylene glycol monomethyl ether chain into an organogold complex in order to achieve such an object.

Patent Document 2 describes a derivative of a pyrrolopyridine compound as a mechanochromic material whose absorption wavelength and color emission wavelength change in response to mechanical stimulation. This derivative changes the fluorescence emission wavelength by 30 nm or more in response to mechanical stimulation.

[1] describes a supramolecular solid-state film whose emission can be switched between red-green-blue colors by controlling the type of mechanical stimulus. This supramolecule consists of two types of pigments (DBDCS and m-BHCDCS) with a pigment weight ratio of 10:3. When this film is subjected to thermal annealing or solvent evaporation annealing, the two dyes form independent phase structures, and emission (blue or green) from DBDCS is observed, and emission from m-BHCDCS is suppressed. be.
On the other hand, when smearing is applied, m-BHCDCS undergoes a phase transition from crystal to amorphous, luminescence (red) from m-BHCDCS is observed, and luminescence from DBDCS is suppressed. This is because the shear force perturbed the structure, resulting in Förster resonance energy transfer (FRET) from DBDCS to m-BHCDCS.

Non-Patent Document 2 describes a binary dye that can switch its emission color among three colors. This binary dye is a mixture of an organic dye that exhibits little mechanochromic emission (bithiophene derivative) and an organic dye that exhibits no mechanochromic emission (DMQA). This change in emission color is caused by the change of the bithiophene derivative from a crystalline state to an amorphous state including a completely amorphous state and an initial crystal structure.

JP 2012-158678 A International Publication No. 2012/039508

Hyeong-Ju Kim, Dong Ryeol Whang, Jhannes Gierschner, Chong Han Lee, Soo Young Park, "High-Contrast Red-Green-Blue Tricolor Fluorescence Switching in Bicomponent Molecular Film”, Angewandte Chemie, 2015, 54, 4330-4333 Suguru Ito, Genki Katada, Tomohiro Taguchi, Izuru Kawamura, Takashi Ubukata, Masatoshi Aasami, "Tricolor mechanochromic luminescence of an organic two-com ponent dye: visualization of a crystalline state and two amorphous states,” CrystEngComm, 2019, 21, 53-59.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique that enables a greater degree of freedom for colors after applying mechanical stimuli.

式（４）中、
Ｒ ^１ 乃至Ｒ ^４ 、及び、Ｒ ^６ 乃至Ｒ ^８ は、それぞれ、互いに独立して水素原子、ハロゲン原子、ヒドロキシ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基、ニトロ基、アミノ基、アミド基、カルボキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ホルミル基、シアノ基、アルキル基、シクロアルキル基、アラルキル基又はアリール基を表し、
Ｒ ^５ は、アルキルオキシカルボニル基、アリールオキシカルボニル基、アシル基、アルキルスルホニル基又はアリールスルホニル基を表し、
Ｒ ^９ は、ハロゲン原子、ヒドロキシ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基、ニトロ基、アミノ基、アミド基、カルボキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ホルミル基、シアノ基、アルキル基、シクロアルキル基、アラルキル基又はアリール基を表す。 According to the first aspect of the present invention, a powder that emits light when irradiated with excitation light, the indolylbenzothiadiazole derivative whose emission spectrum reversibly changes due to mechanical stimulation, and the indolyl benzothiadiazole derivative that has changed due to the mechanical stimulation A cured film comprising polyvinyl alcohol and a powder containing a pigment whose emission spectrum and absorption spectrum at least partially overlap with a drilled benzothiadiazole derivative, wherein the indolylbenzothiadiazole derivative is represented by the following general formula (4): is provided.

In formula (4),
R ¹ to R ⁴ and R ⁶ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amino group, an amido group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a formyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group;
R ⁵ represents an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group,
R9 is a halogen atom, hydroxy group, alkoxy group ^, aralkyloxy group, aryloxy group, nitro group, amino group, amido group, carboxy group, alkyloxycarbonyl group, aryloxycarbonyl group, formyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group or aryl group.

式（４）中、
Ｒ ^１ 乃至Ｒ ^４ 、及び、Ｒ ^６ 乃至Ｒ ^８ は、それぞれ、互いに独立して水素原子、ハロゲン原子、ヒドロキシ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基、ニトロ基、アミノ基、アミド基、カルボキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ホルミル基、シアノ基、アルキル基、シクロアルキル基、アラルキル基又はアリール基を表し、
Ｒ ^５ は、アルキルオキシカルボニル基、アリールオキシカルボニル基、アシル基、アルキルスルホニル基又はアリールスルホニル基を表し、
Ｒ ^９ は、ハロゲン原子、ヒドロキシ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基、ニトロ基、アミノ基、アミド基、カルボキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ホルミル基、シアノ基、アルキル基、シクロアルキル基、アラルキル基又はアリール基を表す。 According to the second aspect of the present invention, a powder that emits light when irradiated with excitation light, the indolylbenzothiadiazole derivative whose emission spectrum reversibly changes due to mechanical stimulation, and the indolyl benzothiadiazole derivative that has changed due to the mechanical stimulation powder containing a dye whose emission spectrum and absorption spectrum at least partially overlap with the dolylbenzothiadiazole derivative, at least one kind of liquid, and polyvinyl alcohol , wherein the indolylbenzothiadiazole derivative has the following general formula (4 ) is provided.

In formula (4),
R ¹ to R ⁴ and R ⁶ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amino group, an amido group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a formyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group;
R ⁵ represents an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group,
R9 is a halogen atom, hydroxy group, alkoxy group ^, aralkyloxy group, aryloxy group, nitro group, amino group, amido group, carboxy group, alkyloxycarbonyl group, aryloxycarbonyl group, formyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group or aryl group.

A third aspect of the present invention provides a laminate comprising a substrate and a cured film according to the first aspect on the substrate.

ADVANTAGE OF THE INVENTION According to this invention, the technique which makes it possible to raise the degree of freedom about the luminescent color after giving a mechanical stimulus is provided.

Schematic which shows an example of the fluorescence spectrum before and behind giving a mechanical stimulus, and an absorption spectrum which concerns on 1st Embodiment. Sectional drawing which shows roughly an example of the laminated body which concerns on 5th Embodiment. FIG. 12 is a schematic cross-sectional view for explaining a phenomenon that occurs when a mechanical stimulus is applied to the laminate according to the fifth embodiment; Sectional drawing which shows roughly the other example of the laminated body which concerns on 5th Embodiment. Fluorescence spectra before and after applying a mechanical stimulus to the powder of Test Example 6. FIG. Fluorescence spectra before and after applying a mechanical stimulus to the laminate of Test Example 24. FIG.

Embodiments of the present invention are described below.

<First Embodiment>
A powder according to a first embodiment of the present invention is a powder that emits light when irradiated with excitation light, and includes an indolylbenzothiadiazole derivative whose emission spectrum reversibly changes due to mechanical stimulation, and the mechanical stimulation. powder containing a luminescent dye whose emission spectrum and absorption spectrum at least partially overlap with the indolylbenzothiadiazole derivative changed by , powder that changes to a luminescent state emitting light of a second color different from the first color under irradiation of the excitation light. Here, as an example, the luminescent dye is a fluorescent dye.

The powder of this embodiment changes the luminescent color of the powder by Förster resonance energy transfer (FRET). FRET is, for example, an interaction involving energy transfer between fluorescent molecules, in which energy is transferred from an excited donor fluorescent molecule to an acceptor fluorescent molecule. Focusing on the luminescence intensity of the donor and the acceptor, when FRET occurs, the luminescence intensity of the donor decreases and the luminescence intensity of the acceptor increases compared to when FRET does not occur. FRET is not the result of acceptor absorption of donor emission, and there are no intermediate photons to mediate FRET. FRET is the interaction of oscillating electric dipoles and the resonance of electronic dipoles near the resonance frequency. Therefore, FRET is a phenomenon similar to the behavior of conjugate vibrations. Thus, in FRET, the excitation energy does not become an electromagnetic wave but moves between two adjacent fluorescent molecules by electron resonance.

FRET occurs when the distance between fluorescent molecules is, for example, 10 nm or less, the emission spectrum of the donor and the absorption spectrum of the acceptor overlap, and the orientation factors of the donor and acceptor are appropriate.

In the powder of this embodiment, an indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation is used as a donor, and a fluorescent dye is used as an acceptor.

(Indolylbenzothiadiazole derivative whose emission spectrum changes reversibly by mechanical stimulation)
An indolylbenzothiadiazole derivative whose emission spectrum changes reversibly by mechanical stimulus changes its emission spectrum by, for example, applying friction as a mechanical stimulus to the compound. Emission color changes. After the emission color changes, the emission color reverts to the emission color before applying a mechanical stimulus, by heating or exposure to solvent vapors, or spontaneously.

Examples of mechanical stimulation include, but are not limited to, friction, compression, stretching, impact, shearing, pulverization, bending, and ultrasonic waves.

Such an indolylbenzothiadiazole derivative is preferably a compound whose luminescent color spontaneously returns to the luminescent color before the application of mechanical stimulation. Compounds that spontaneously return in the vicinity are preferred. Room temperature is, for example, 10° C. or higher and 35° C. or lower.

The indolylbenzothiadiazole derivative is preferably a compound represented by the following general formula (1).

In formula (1), R ¹ to R ⁴ and R ⁶ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, represents an amino group, an amido group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a formyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group,
R ⁵ represents an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group,
^R9 is a halogen atom, hydroxy group, alkoxy group, aralkyloxy group, aryloxy group, nitro group, amino group, amido group, carboxy group, alkyloxycarbonyl group, aryloxycarbonyl group, formyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group or aryl group.

The indolylbenzothiadiazole derivative preferably has a group containing a tert-butoxycarbonyl group on the nitrogen atom of the indolyl group, and particularly preferably a compound represented by the following formula (2).

(Fluorescent dye)
Any fluorescent dye may be used as long as it is excited by energy transfer from the indolylbenzothiadiazole derivative. Examples of such fluorescent dyes include xanthene dyes, cyanine dyes, squalium dyes, coumarin dyes, triphenylmethane dyes, and pyrimidine dyes.

Examples of xanthene dyes include sulforhodamine B, gallein, acid red 289, bromopyrogallol red, 2′,7′-dichlorofluorescein sodium, 9-(4′-dimethylaminophenyl)-2,6,7-trihydroxy Fluorone Sulfate Hydrate, Dibromofluorescein, Acid Red 91, Uranine K, Fluorescein, Pyrogallol Red, Rhodamine 6G, Rhodamine B, Acid Red 94, Rhodamine 19, Rhodamine 110 Chloride, Rhodamine 590 Chloride, Rhodamine 700, Rhodamine 800, Peroxide Rhodamine chlorate 19, rhodamine perchlorate 640, sulfonefluorescein, sulforhodamine 101, tetrabromofluorescein potassium, acid red 87, 2′,4′,5′,7′-tetrabromo-3,4,5,6-tetra Chlorofluorescein, Acid Red 92, 3,4,5,6-tetrachlorofluorescein, phenylfluorone, and erythrosine B.

Examples of cyanine dyes include 1,1′-diethyl-3,3,3′,3′-tetramethylindocarbocyanine iodide, cryptocyanin, cyanine, 3,3′-diethyloxacarbocyanine iodide, 3 , 3′-dipropylthiadicarbocyanine iodide, 3,3′-diethyloxadicarbocyanine iodide, 3,3,3′,3′-tetramethyl-1,1′-bis(4-sulfobutyl) Benzoindodicarbocyanine sodium, 3,3,3′,3′-tetramethyl-1,1′-bis(4-sulfobutyl)indocarbocyanine sodium, 3,3′-diethylthiatricarbocyanine iodide, 1, 1′-dibutyl-3,3,3′,3′-tetramethylindotricarbocyanine hexafluorophosphate, indocyanine green, IR 775 chloride, IR 676 iodide, IR 783, pinacyanol chloride, and pinacyanol iodide.

Examples of squalium dyes include 2,4-bis[4-(diethylamino)-2-hydroxyphenyl]squaraine and 2,4-bis[8-hydroxy-1,1,7,7-tetramethyljulolidine- 9-yl]squaraine.

Examples of coumarin pigments include Solvent Red 197.

Examples of triphenylmethane dyes include Basic Green 1, Erio Green B, Acid Green 9, and Malachite Green oxalate.

The maximum absorption wavelength of the fluorescent dye is preferably 500 nm or more, more preferably 500 nm or more and 650 nm or less, and even more preferably 520 nm or more and 650 nm or less. As the maximum absorption wavelength of the fluorochrome increases, it becomes more difficult to excite the fluorochrome due to energy transfer from the indolylbenzothiadiazole derivative. On the other hand, the shorter the maximum absorption wavelength of the fluorescent dye, the smaller the change in emission color before and after applying the mechanical stimulus.

The amount of the fluorescent dye relative to 100 parts by mass of the indolylbenzothiadiazole derivative may be 20 parts by mass or less, 10 parts by mass or less, 5 parts by mass or less, or 3 parts by mass or less. , 1 part by mass or less, or 0.1 part by mass or less. Moreover, it may be 0.001 parts by mass or more, or may be 0.01 parts by mass or more. Since the luminescence intensity of the indolylbenzothiadiazole derivative decreases as the amount of the fluorescent dye increases, it becomes difficult to confirm luminescence from the powder. In addition, as the amount of fluorescent dye increases, the time required for the change from the luminescent color after applying the mechanical stimulus to the luminescent color before applying the mechanical stimulus lengthens. That is, the recovery speed of the emission color becomes slow. On the other hand, as the amount of the fluorescent dye decreases, it becomes difficult to confirm the decrease in the emission intensity of the indolylbenzothiadiazole derivative before and after applying the mechanical stimulation to the powder.

This powder satisfies, for example, the following formula (3).

J _after /J _before >1 (3)

In formula (3), J _after is represented by the following formula (4), J _before is represented by the following formula (5), and I _λ ^D (λ) _after imparted a mechanical stimulus to the indolylbenzothiadiazole derivative. _is the fluorescence _spectrum normalized by ^the area immediately _after ; is the molar extinction coefficient of the dye and λ is the wavelength.

By satisfying the above conditions, applying a mechanical stimulus can cause a change in which the emission intensity of the fluorescent dye increases due to Förster resonance energy transfer (FRET). The reason will be described below with reference to FIG.

FIG. 1 is a schematic diagram showing an example of a fluorescence spectrum and an absorption spectrum before and after applying a mechanical stimulus according to this embodiment. As shown in FIG. 1, fluorescence spectrum 1 before mechanical stimulation is applied to the indolylbenzothiadiazole derivative shifts to fluorescence spectrum 2 by applying mechanical stimulation. Due to this fluorescence spectrum shift, the degree of overlap with the absorption spectrum 3 of the fluorescent dye changes.

The magnitude of this overlap is expressed by Equations (4) and (5) above. That is, the above formula (4) corresponds to the degree of overlap between the fluorescence spectrum 2 and the absorption spectrum 3, and the above formula (5) corresponds to the degree of overlap between the fluorescence spectrum 1 and the absorption spectrum 3. As the fluorescence spectrum of the indolylbenzothiadiazole derivative changes as described above, the overlap with the absorption spectrum 3 of the fluorescent dye increases. As a result, FRET from the indolylbenzothiadiazole derivative to the fluorescent dye occurs efficiently, which is thought to increase the emission intensity of the fluorescent dye.

In FIG. 1, the change in the luminescent color of the powder according to the present embodiment is from the luminescent color corresponding to the maximum emission wavelength of fluorescence spectrum 1 of the indolylbenzothiadiazole derivative to the maximum emission wavelength of fluorescence spectrum 4 of the fluorescent dye. corresponds to a change in emission color to Since there are many options for fluorescent dyes that can be used, combining a fluorescent dye with an indolylbenzothiadiazole derivative can increase the degree of freedom in changing the emission color.

Light emission from the powder can be confirmed, for example, by irradiating it with excitation light. Although the wavelength of the excitation light is not particularly limited, it is preferably in the range of 100 nm or more and 500 nm or less, more preferably in the range of 200 nm or more and 460 nm or less, and 250 nm or more and 450 nm or less. is more preferred. As the wavelength of the excitation light becomes longer, it becomes more difficult to excite the indolylbenzothiadiazole derivative.

The maximum emission wavelength of the powder preferably changes by 40 nm or more, more preferably by 60 nm or more, and even more preferably by 100 nm or more before and after the mechanical stimulation is applied.

(Additive)
The powder of the present embodiment may contain a material other than the indolylbenzothiadiazole derivative or the fluorescent dye as an additive within a range that does not impair the effects of the present invention. Additives include, for example, inorganic layered compounds, inorganic acicular minerals, antifoaming agents, inorganic particles, organic particles, lubricants, antioxidants, antistatic agents, ultraviolet absorbers, stabilizers, magnetic powders, orientation Accelerators, plasticizers, cross-linking agents, magnetic substances, pharmaceuticals, agricultural chemicals, fragrances, adhesives, enzymes, pigments, dyes, deodorants, metals, metal oxides, and inorganic oxides.

The content of the additive is preferably 20 parts by mass or less with respect to 100 parts by mass of the indolylbenzothiadiazole derivative. When the content of the additive is within this range, the emission intensity of the powder can be maintained.

The powders of this embodiment may be mixed with liquids, for example, for ease of handling. As the liquid, it is preferable to use a compound that is liquid at 25°C. Such liquids include, for example, water, ethers, ketones, esters, alcohols, and amides. One type of liquid may be used, or two or more types may be used.

Ethers include, for example, dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, dioxane, dioxolane, trioxane, tetrahydrofuran, anisole, and phenetole.

Ketones include, for example, acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, and methylcyclohexanone.

Esters include, for example, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, n-pentyl acetate, 2-ethoxyethyl acetate, and γ-butyrolactone. .

Alcohols include, for example, ethanol, isopropyl alcohol, 2-methoxyethanol, 2-ethoxyethanol, and 2-butoxyethanol.

Amides include, for example, dimethylformamide and dimethylacetamide.

Next, a method for measuring the fluorescence spectrum of the powder, a method for confirming the luminescent color of the powder, and a method for confirming a change in the luminescent color of the powder will be described.

(Method for measuring fluorescence spectrum of powder)
The fluorescence spectrum of the powder is measured using a spectrofluorometer. Specifically, luminescence when the powder is irradiated with ultraviolet rays of 365 nm is measured with a spectrofluorophotometer. As this spectrofluorophotometer, for example, a compact spectrometer USB2000+ manufactured by Ocean Optics can be used.

(Method for confirming luminescent color of powder)
The luminescent color of the powder is visually confirmed. Specifically, luminescence is observed when the powder is irradiated with ultraviolet rays of 365 nm.

The luminescent color of the powder is, for example, violet, blue, blue-green, green, yellow, orange, or red. When it is recognized that it is not emitting light, the emission color is black. The wavelength corresponding to each emission color is, for example, 380 nm or more and less than 430 nm for purple, 430 nm or more and less than 460 nm for blue, 460 nm or more and less than 500 nm for blue-green, 500 nm or more and less than 570 nm for green, and 570 nm for yellow. 590 nm or more and less than 590 nm, 590 nm or more and less than 610 nm for orange, and 610 nm or more and 780 nm or less for red.

(Method for confirming change in luminescent color of powder)
First, the luminescent color of the powder before mechanical stimulus is confirmed by the above confirmation method. Next, the powder is rubbed with, for example, a spatula as a mechanical stimulus. Immediately after rubbing, the luminescent color of the rubbed portion is confirmed by the above confirmation method. After a certain period of time elapses, for example, after 1 minute, the color of light emitted from the rubbed portion is confirmed by the above confirmation method.

(Method for producing powder)
For example, an indolylbenzothiadiazole derivative and a fluorescent dye are mixed into the above liquid. A powder can be obtained by applying this mixture to a substrate and removing the liquid in the mixture, for example, by heating. Application of the mixture may be performed only once or may be performed multiple times. Alternatively, the composition may be applied onto another base material, for example, a transfer base material, and then transferred.

The base material is not particularly limited, but can be appropriately selected according to the purpose of use of the mixture. Substrates include, for example, polyethylene terephthalate (PET), polypropylene (PP), polyethylene terephthalate copolymer (PETG), polyvinyl chloride (PVC), glass, silicone, nonwovens, mesh, paper, and pulp.

Methods for applying the mixture to the substrate include, for example, brush coating, brush coating, trowel coating, bar coater, knife coater, doctor blade, screen printing, spray coating, inkjet printing, spin coater, applicator, roll coater, flow coater, and centrifugal coater. , ultrasonic coater, (micro) gravure coater, dip coating, flexographic printing, potting, or scraping.

The powder according to the first embodiment is a powder that emits light when irradiated with excitation light, and includes an indolylbenzothiadiazole derivative whose emission spectrum reversibly changes due to mechanical stimulation, and the above-mentioned A powder containing a fluorescent dye having an absorption spectrum at least partially overlapping with an emission spectrum of an indolylbenzothiadiazole derivative, wherein the excitation light is emitted from an emission state that emits light of a first color under irradiation with the excitation light. It is a powder that changes to a luminous state that emits light of a second color different from the first color under irradiation. Therefore, the powder according to the first embodiment can increase the degree of freedom in color after applying mechanical stimulation.

<Second embodiment>
A powder according to a second embodiment of the present invention is a powder that emits light when irradiated with excitation light, and comprises an indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation, and the mechanical stimulation. powder containing a dye whose emission spectrum and absorption spectrum at least partially overlap with the indolylbenzothiadiazole derivative changed by , powder that changes to a non-light-emitting state that does not emit light under irradiation with the excitation light.

As in the first embodiment, the powder of this embodiment changes from a luminous state to a non-luminous state by Förster resonance energy transfer (FRET). In the powder of the present embodiment, an indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation is used as a donor, and a dye is used as an acceptor. When FRET occurs, energy transfer occurs from a donor to an acceptor. When the acceptor is a compound that does not emit light (non-luminescent dye) even when energy transfer to the acceptor occurs, the powder of the present embodiment changes from a luminescent state to a non-luminescent state. In addition, since concentration quenching occurs as the amount of dye in the powder increases, even if a luminous dye such as a fluorescent dye is used, the state changes to a non-luminous state. Such a change is a special color change that cannot be realized with the powder of the first embodiment.

(Indolylbenzothiadiazole derivative whose emission spectrum changes reversibly by mechanical stimulation)
As the indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation, for example, compounds similar to the compounds exemplified in the first embodiment can be used.

(pigment)
Any dye can be used as long as it can receive energy transfer from an indolylbenzothiadiazole derivative whose emission spectrum reversibly changes due to mechanical stimulation. Such dyes include, for example, non-luminescent dyes and luminescent dyes.

Examples of non-luminescent dyes that can be used include merocyanine dyes, tetraazaporphyrin dyes, and phthalocyanine dyes.

As the luminescent dye, for example, fluorescent dyes such as xanthene dyes, cyanine dyes, squalium dyes, coumarin dyes, triphenylmethane dyes, and pyrimidine dyes can be used in the same manner as the dyes exemplified in the first embodiment.

The maximum absorption wavelength of the dye is preferably 500 nm or more, more preferably 500 nm or more and 650 nm or less, and even more preferably 520 nm or more and 650 nm or less.

In the case of a non-luminescent dye, the amount of the dye with respect to 100 parts by mass of the indolylbenzothiadiazole derivative whose emission spectrum changes reversibly by mechanical stimulation may be 20 parts by mass or less, and may be 10 parts by mass or less. 5 parts by mass or less, 3 parts by mass or less, 1 part by mass or less, or 0.1 parts by mass or less. Moreover, it may be 0.001 parts by mass or more, or may be 0.01 parts by mass or more. As the amount of fluorescent dye increases, the luminescence intensity of the indolylbenzothiadiazole derivative whose luminescence spectrum changes reversibly by mechanical stimulation decreases, making it difficult to confirm luminescence from the powder. On the other hand, as the amount of fluorescent dye decreased, it was confirmed that the emission intensity of the indolylbenzothiadiazole derivative, whose emission spectrum reversibly changes due to mechanical stimulation, decreased before and after mechanical stimulation was applied to the powder. become difficult.

In the case of a luminescent dye, the amount of the dye with respect to 100 parts by mass of the indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation may be in the range of more than 10 parts by mass and not more than 100 parts by mass.

(Additive)
As the additive, the same additive as in the first embodiment can be used.

Further, for example, the powder according to the present embodiment may be mixed with a liquid in order to facilitate handling. As the liquid, the same liquid as in the first embodiment can be used.

The method of measuring the fluorescence spectrum of the powder, the method of checking the luminescent color of the powder, the method of checking the change in the luminescent color of the powder, and the method of manufacturing the powder according to the present embodiment are also the same as in the first embodiment. be.

The powder according to the second embodiment is a powder that emits light when irradiated with excitation light, and includes an indolylbenzothiadiazole derivative whose emission spectrum reversibly changes due to mechanical stimulation, and an indolylbenzothiadiazole derivative that changes due to the mechanical stimulation. A powder containing a dye whose absorption spectrum at least partially overlaps with the emission spectrum of the indolylbenzothiadiazole derivative, wherein the mechanical stimulus converts a luminescent state in which light is emitted under irradiation of the excitation light to the excitation light. It is a powder that changes to a non-luminous state that does not emit light under irradiation of light. Therefore, the powder according to the second embodiment can increase the degree of freedom in color after applying mechanical stimulation.

<Third Embodiment>
The coating liquid according to the third embodiment contains powder and at least one type of liquid.

(powder)
As the powder, the powder of the first embodiment or the second embodiment is used.

(liquid)
The liquid is a dispersion medium that does not completely dissolve at least the indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation. The liquid preferably contains at least one water-based resin. By using a water-based resin, it is possible to improve the dispersibility of the powder and improve the coatability. Only one type of water-based resin may be used, or two or more types may be used. Moreover, from the viewpoint of environmental load, it is preferably a naturally occurring polymer.

Examples of water-based resins include proteins, vinyl-based resins, acrylic-based resins, polyethylene-based resins, urethane-based resins, and epoxy-based resins.

Proteins include, for example, gelatin, casein, and sodium chondroitin sulfate.

Examples of vinyl-based resins include polyvinyl alcohol, polyvinylpyrrolidone, and polyvinylpyrrolidone-vinyl acetate copolymer. In particular, polyvinyl alcohol is preferable because the indolylbenzothiadiazole derivative is easily dispersed.

Examples of acrylic resins include sodium polyacrylate, carboxyvinyl polymer, polyacrylamide, and acrylamide/acrylate copolymer.

Polyethylene-based resins include, for example, polyethylene imine, polyethylene oxide, and polyethylene glycol.

The amount of the indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation is preferably 0.1 parts by mass or more, and 5 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the aqueous resin. is more preferable.

A coating liquid according to the third embodiment contains the powder according to the first or second embodiment. Therefore, the coating liquid according to the third embodiment can provide a film with a higher degree of freedom in terms of color after applying a mechanical stimulus.

<Fourth Embodiment>
A cured film according to the fourth embodiment contains the powder of the first or second embodiment.

The cured film according to the present embodiment is a film obtained by removing the liquid from the coating film of the coating liquid according to the third embodiment and curing it. can be formed using the method of Hereinafter, it is also referred to as a mechanical stimulus response layer.

The thickness of the cured film is not particularly limited, and can be appropriately set according to the application. For example, from the viewpoint of productivity, moldability, and operability during construction, the film thickness of the cured film may be 5 μm or more and 1000 μm or less, and may be 10 μm or more and 500 μm or less.

The cured film according to the present embodiment may be a self-supporting film that can be handled independently, or may be included in a laminate described below.

<Fifth Embodiment>
A laminate according to a fifth embodiment comprises a substrate and a cured film on the substrate. Hereinafter, a laminate according to this embodiment will be described with reference to the drawings. However, in each drawing described below, the same reference numerals are given to the parts that correspond to each other, and the description of overlapping parts will be omitted as appropriate.

FIG. 2A is a cross-sectional view schematically showing a laminate 5 according to the fifth embodiment. This laminate 5 comprises a substrate 6 and a cured film 7 formed on the substrate 6 .

(Base material)
The material of the base material 6 can be appropriately selected according to the intended use of the laminate 5 . As the material of the base material 6, for example, a plastic material can be used.

Examples of plastic materials include polyolefin (polyethylene, polypropylene), polyester (polyethylene naphthalate, polyethylene terephthalate), polyamide (nylon-6, nylon-66), polystyrene, ethylene vinyl alcohol, polyvinyl chloride, polyimide, polyvinyl alcohol, Polycarbonate, polyethersulfone, and lyllcellulose (triacetylcellulose, diacetylcellulose).

The surface of the substrate 6 on which the cured film 7 is provided may be surface-treated. The surface treatment facilitates the coating of the coating liquid onto the base material 6 and improves the adhesion between the base material 6 and the cured film 7 . Examples of surface treatment include corona treatment and plasma treatment. In addition, for example, when the cured film 7 which is a mechanical stimulus responsive layer is a self-supporting film, the substrate 6 can be omitted.

(cured film)
The cured film 7, which is a mechanical stimulus responsive layer, contains the powder according to the first or second embodiment. FIG. 2B shows a part 7a of the cured film 7 of the laminate 5 where a mechanical stimulus is applied. A portion 7a of the cured film 7 to which a mechanical stimulus is applied changes the maximum emission wavelength or decreases the emission intensity. More specifically, in the cured film 7, the maximum wavelength of light emission that can be confirmed from the site 7a to which the mechanical stimulation is applied is shifted, for example, by 100 nm or more from the maximum wavelength before the stimulation is applied, or the mechanical stimulation is applied. Light emission cannot be confirmed from the portion 7a. As the shift of the maximum wavelength becomes smaller, it may become difficult to visually confirm the change in emission color. In addition, luminescence can be measured with a spectrofluorophotometer.

The film thickness of the cured film 7 is not particularly limited, and can be appropriately set according to the application. For example, from the viewpoint of productivity, moldability, and operability during construction, the film thickness of the cured film may be 5 μm or more and 1000 μm or less, and may be 10 μm or more and 500 μm or less.

(adhesion layer)
An adhesive layer (not shown) may be further provided between the substrate 6 and the cured film 7 for the purpose of improving the adhesion between the substrate 6 and the cured film 7 . Examples of adhesive components used to form the adhesive layer include phenolic resins, urea resins, melamine resins, polyvinyl resins, polyolefin resins, urethane resins, epoxy resins, acrylic resins, polyester resins, polyamide resins, polystyrene resins, and the like. resin. Among them, it is preferable to use a polyvinyl resin, a polyolefin resin, or an acrylic resin as the adhesive resin because of its good adhesion.

(overcoat layer)
FIG. 3 is a cross-sectional view schematically showing a laminate 15 according to the fifth embodiment. The laminate 15 comprises an optionally provided substrate 6 , a cured film 7 and an optionally provided overcoat layer 16 in this order. The overcoat layer 16 is provided mainly from the viewpoint of scratch resistance. The material of the overcoat layer 16 is not particularly limited, but examples thereof include thermosetting or photo-curing resins such as urethane-based resins, acrylic-based resins, silicone-based resins, and fluorine-based resins.

Next, a method for measuring the fluorescence spectrum of the laminate, a method for confirming the emission color of the laminate, and a method for confirming a reversible change in the emission color of the laminate will be described.

(Method for Measuring Fluorescence Spectrum of Laminate and Method for Confirming Emission Color of Laminate)
The method for measuring the fluorescence spectrum of the laminate and the method for confirming the emission color of the laminate are both the method for measuring the fluorescence spectrum of the powder according to the first embodiment and the confirmation method for the emission color of the powder according to the first embodiment. It is a method similar to the method.

(Method for confirming reversible change in emission color of laminate)
First, the luminescent color of the laminate before mechanical stimulation is confirmed by the above confirmation method. Next, as a mechanical stimulus, for example, the laminate is rubbed with a spatula. Immediately after rubbing, the luminescent color of the rubbed portion is confirmed by the above confirmation method. After a certain period of time has elapsed, for example, after 7 days, the luminescent color of the rubbed portion is confirmed by the above confirmation method.

A laminate according to the fifth embodiment includes the stiffening layer according to the fourth embodiment. Therefore, the layered product according to the fifth embodiment can increase the degree of freedom regarding the color after applying the mechanical stimulus.

The powders, coating liquids, cured films, and laminates described above can be used, for example, in recording media, decorative sheets, anti-counterfeiting tables themselves, and sensing media.

The present invention will be described in more detail below with test examples, but the present invention is not limited to these.

<Experimental Example 1: Powder>
(Test example 1)
In Test Example 1, the powder of Test Example 1 was produced by the following procedure.

An indolylbenzothiadiazole derivative represented by the above formula (2) was prepared as a donor, and NK-9940 (manufactured by Hayashibara Co., Ltd.) was prepared as an acceptor. The indolylbenzothiadiazole derivative represented by the above formula (2) was prepared according to the method described in JP-A-2017-57191.

Indolylbenzothiadiazole derivative and NK-9940 were added to methanol so that their concentrations were 7.9 g/L and 7.9×10 ⁻² g/L, respectively. That is, NK-9940 was adjusted to 1 part by mass with respect to 100 parts by mass of the indolylbenzothiadiazole derivative.

The resulting solution was stirred with a magnetic stirrer for 1 hour to dissolve the indolylbenzothiadiazole derivative and NK-9940. About 50 mg of this solution was dropped on glass and dried at room temperature for 5 minutes to obtain powder.

(Test example 2)
In Test Example 2, as shown in Table 1, powder was obtained in the same manner as in Test Example 1, except that rhodamine 110 chloride (manufactured by ALDRICH) was used instead of NK-9940.

(Test example 3)
In Test Example 3, as shown in Table 1, powder was obtained in the same manner as in Test Example 1, except that Acid Red 289 (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of NK-9940.

(Test example 4)
In Test Example 4, as shown in Table 1, powder was obtained in the same manner as in Test Example 1, except that NK-4674 (manufactured by Hayashibara Co., Ltd.) was used instead of NK-9940.

(Test Example 5)
In Test Example 5, as shown in Table 1, powder was obtained in the same manner as in Test Example 1, except that sulforhodamine B (manufactured by ALDRICH) was used instead of NK-9940.

(Test example 6)
In Test Example 6, as shown in Table 1, powder was obtained in the same manner as in Test Example 1, except that rhodamine perchlorate 640 (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of NK-9940. .

(Test Example 7)
In Test Example 7, as shown in Table 1, powder was obtained in the same manner as in Test Example 1 except that sulforhodamine 101 (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of NK-9940.

(Test Example 8)
In Test Example 8, as shown in Table 1, powder was obtained in the same manner as in Test Example 1 except that NK-10676 (manufactured by Hayashibara Co., Ltd.) was used instead of NK-9940.

(Test Example 9)
In Test Example 9, as shown in Table 1, 2,4-bis[4-(diethylamino)-2-hydroxyphenyl]squaraine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of NK-9940, and methanol was used. A powder was obtained in the same manner as in Test Example 1, except that dichloromethane was used instead.

(Test Example 10)
In Test Example 10, as shown in Table 1, powder was obtained in the same manner as in Test Example 1 except that Rhodamine 700 (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of NK-9940.

(Test Example 11)
In Test Example 11, as shown in Table 1, powder was obtained in the same manner as in Test Example 1 except that Rhodamine 800 (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of NK-9940.

(Test Example 12)
In Test Example 12, as shown in Table 1, instead of NK-9940, 3,3,3′,3′-tetramethyl-1,1′-bis(4-sulfobutyl)benzoindodicarbocyanine sodium (Tokyo Kasei Kogyo Co., Ltd.) was used in the same manner as in Test Example 1 to obtain a powder.

(Test Example 13)
In Test Example 13, as shown in Table 1, instead of NK-9940, 1,1'-dibutyl-3,3,3',3'-tetramethylindotricarbocyanine hexafluorophosphate (Tokyo Chemical Industry Co., Ltd. A powder was obtained in the same manner as in Test Example 1, except that the company's product) was used.

(Test Example 14)
In Test Example 14, as shown in Table 1, rhodamine perchlorate 640 was used instead of NK-9940, except that the concentration of rhodamine perchlorate 640 was 7.9×10 ⁻¹ g/L. A powder was obtained in the same manner as in Test Example 1. That is, in this example, 10 parts by mass of rhodamine perchlorate 640 was added to 100 parts by mass of the indolylbenzothiadiazole derivative.

(Test Example 15)
In Test Example 15, as shown in Table 1, rhodamine perchlorate 640 was used instead of NK-9940, except that the concentration of rhodamine perchlorate 640 was 7.9×10 ⁻⁴ g/L. A powder was obtained in the same manner as in Test Example 1. That is, in this example, 0.01 part by mass of rhodamine perchlorate 640 was used with respect to 100 parts by mass of the indolylbenzothiadiazole derivative.

(Test Example 16)
In Test Example 13, as shown in Table 1, powder was obtained in the same manner as in Test Example 1 except that FDG-004 (manufactured by Yamada Chemical Industry Co., Ltd.) was used instead of NK-9940.

(Test Example 17)
In Test Example 17, as shown in Table 1, powder was obtained in the same manner as in Test Example 1, except that NK-9940 was not used.

(Test Example 18)
In Test Example 18, as shown in Table 1, rhodamine perchlorate 640 was used instead of NK-9940, and the concentration of rhodamine perchlorate 640 was 7.9 g/L. powder was obtained. That is, in this example, 100 parts by mass of rhodamine perchlorate 640 was added to 100 parts by mass of the indolylbenzothiadiazole derivative.

(Test Example 19)
In Test Example 19, as shown in Table 1, powder was prepared in the same manner as in Test Example 1 except that no indolylbenthiadiazole derivative was used and rhodamine perchlorate 640 was used instead of NK-9940. got a body

(Measurement of fluorescence spectrum)
The powder of Test Example 6 was subjected to fluorescence spectrum measurement according to the method described above. The results are shown in FIG. The spectra shown in FIG. 4 are fluorescence spectra before and after mechanical stimulation was applied to the powder of Test Example 6. FIG. The horizontal axis of FIG. 4 is the wavelength (nm). The vertical axis in FIG. 4 is the normalized irradiance. In addition, Table 1 shows the maximum emission wavelength (nm) before mechanical stimulation, the maximum emission wavelength (nm) derived from the acceptor after mechanical stimulation, and the emission color.

The spectrum shown in FIG. 4 had a maximum emission wavelength of 467 nm before applying mechanical stimulation, and a maximum emission wavelength of 607 nm after applying mechanical stimulation. Five minutes after applying the mechanical stimulus, the maximum emission wavelength coincided with the maximum emission wavelength before applying the mechanical stimulus.

(Evaluation method)
For the powders produced in Test Examples 1 to 19, mechanical stimulation was applied according to the method described above, and the emission color and maximum emission wavelength (nm) before applying mechanical stimulation and the emission color after applying mechanical stimulation and the maximum emission wavelength (nm) derived from the acceptor was obtained. From this wavelength, the amount of change (nm) in the maximum emission wavelength before and after the mechanical stimulus was applied was calculated. In addition, after applying the mechanical stimulation, it was confirmed whether or not the color spontaneously recovered to the color before the application of the mechanical stimulation. These results are shown in Table 1.

As shown in Table 1, the powders of Test Examples 1 to 16 produced different color changes than the powder of Test Example 17. Moreover, the powders of Test Examples 18 and 19 did not emit light both before and after applying the mechanical stimulus.

<Experimental Example 2: Coating liquid and laminate>
(Test Example 20)
In Test Example 20, a coating liquid was prepared and a laminate was produced according to the following procedures.
An indolylbenzothiadiazole derivative represented by the above formula (5) was prepared as a donor, and NK-9940 was prepared as an acceptor. The indolylbenzothiadiazole derivative represented by the above formula (5) was prepared according to the method described in Non-Patent Document 2. Also, an aqueous solution of polyvinyl alcohol (PVA105, manufactured by Kuraray Co., Ltd.) having a solid content of 10% was prepared as a liquid.

The indolylbenzothiadiazole derivative was dispersed in polyvinyl alcohol so that its concentration was 5% by mass relative to polyvinyl alcohol. Also, NK-9940 was dissolved in polyvinyl alcohol so that its concentration was 1% by mass with respect to the indolylbenzothiadiazole derivative. That is, the indolylbenzothiadiazole derivative was coated in an amount of 5 parts by mass with respect to 100 parts by mass of polyvinyl alcohol, and the indolylbenzothiadiazole derivative was coated in an amount of 1 part by mass with respect to 100 parts by mass of the indolylbenzothiadiazole derivative. A working solution was prepared.

The obtained coating liquid was applied to a polyethylene terephthalate film having a thickness of 75 μm using a bar coater so that the film thickness after drying was 10 μm, and dried at 60° C. to obtain a laminate.

(Test Example 21)
In Test Example 21, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20 except that rhodamine 110 chloride was used instead of NK-9940.

(Test Example 22)
In Test Example 22, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that Acid Red 289 was used instead of NK-9940.

(Test Example 23)
In Test Example 23, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20 except that NK-4674 was used instead of NK-9940.

(Test Example 24)
In Test Example 24, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that sulforhodamine B was used instead of NK-9940.

(Test Example 25)
In Test Example 25, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20 except that rhodamine perchlorate 640 was used instead of NK-9940.

(Test Example 26)
In Test Example 26, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that sulforhodamine 101 was used instead of NK-9940.

(Test Example 27)
In Test Example 27, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20 except that NK-10676 was used instead of NK-9940.

(Test Example 28)
In Test Example 28, as shown in Table 2, the same procedure as in Test Example 20 was performed except that 2,4-bis[4-(diethylamino)-2-hydroxyphenyl]squaraine was used instead of NK-9940. A coating liquid and a laminate were obtained.

(Test Example 29)
In Test Example 29, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20 except that Rhodamine 700 was used instead of NK-9940.

(Test Example 30)
In Test Example 30, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that Rhodamine 800 was used instead of NK-9940.

(Test Example 31)
In Test Example 31, as shown in Table 2, 3,3,3′,3′-tetramethyl-1,1′-bis(4-sulfobutyl)benzoindodicarbocyanine sodium was used instead of NK-9940. A coating liquid and a laminate were obtained in the same manner as in Test Example 20 except for the above.

(Test Example 32)
In Test Example 32, as shown in Table 2, 1,1'-dibutyl-3,3,3',3'-tetramethylindotricarbocyanine hexafluorophosphate was used instead of NK-9940. obtained a coating liquid and a laminate in the same manner as in Test Example 20.

(Test Example 33)
In Test Example 33, as shown in Table 1, rhodamine perchlorate 640 was used in place of NK-9940, and rhodamine perchlorate 640 was 10 parts by mass per 100 parts by mass of the indolylbenzothiadiazole derivative. A coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that the

(Test Example 34)
In Test Example 34, as shown in Table 1, rhodamine perchlorate 640 was used in place of NK-9940. A coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that the

(Test Example 35)
In Test Example 35, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that FDG-004 was used instead of NK-9940.

(Test Example 36)
In Test Example 36, as shown in Table 2, a coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that NK-9940 was not used.

(Test Example 37)
In Test Example 37, as shown in Table 2, rhodamine perchlorate 640 was used in place of NK-9940 so that 100 parts by mass of rhodamine perchlorate 640 was used with respect to 100 parts by mass of the indolylbenzothiadiazole derivative. A coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that the

(Test Example 38)
In Test Example 38, as shown in Table 2, coating was performed in the same manner as in Test Example 20 except that no indolylbenthiadiazole derivative was used and rhodamine perchlorate 640 was used instead of NK-9940. A working solution and a laminate were obtained.

(Test Example 39)
In Test Example 39, as shown in Table 2, sulforhodamine B was used instead of NK-9940, polyvinyl acetate (manufactured by ALDRICH) having a weight average molecular weight (Mw) of about 100000 was used as the resin, and methyl ethyl ketone was used instead of water. A coating liquid and a laminate were obtained in the same manner as in Test Example 20, except that the was used.

(Measurement of fluorescence spectrum)
The laminate of Test Example 24 was subjected to fluorescence spectrum measurement according to the method described above. The results are shown in FIG. The spectra shown in FIG. 5 are fluorescence spectra before and after applying a mechanical stimulus to the laminate of Test Example 24. FIG. The horizontal axis of FIG. 5 is the wavelength (nm). The vertical axis in FIG. 5 is the normalized irradiance. Table 2 shows the maximum emission wavelength (nm) before mechanical stimulation, the maximum emission wavelength (nm) derived from the acceptor after mechanical stimulation, and the emission color.

The spectrum shown in FIG. 5 has peaks P ₁₁ (457 nm) and P ₁₂ (487 nm) derived from the indolylbenzothiadiazole derivative and peaks P ₂₁ (588 nm) and P ₂₂ (588 nm) derived from sulforhodamine B. be. Upon application of the mechanical stimulus, peak _P11 shifted to the long wavelength to peak _P12 while the illuminance increased from peak _P21 to peak _P22 . From this, it was possible to confirm that FRET was occurring.

(Evaluation method)
For the coating liquids and laminates obtained in Test Examples 20 to 39, mechanical stimulation was applied according to the method described above, and the emission color and maximum emission wavelength (nm) before and after the application of mechanical stimulation, and mechanical stimulation The emission color after the addition of and the maximum emission wavelength (nm) derived from the acceptor were obtained. From these wavelengths, the amount of change (nm) in the maximum emission wavelength before and after the application of the mechanical stimulus was calculated. In addition, after applying the mechanical stimulation, it was confirmed whether or not the color spontaneously recovered to the color before the application of the mechanical stimulation. These results are shown in Table 2.

［８］
前記インドリルベンゾチアジアゾール誘導体が下記一般式（４）で表される項１乃至７の何れか１項に記載の粉体。

式（４）中、
Ｒ ^１ 乃至Ｒ ^４ 、及び、Ｒ ^６ 乃至Ｒ ^８ は、それぞれ、互いに独立して水素原子、ハロゲン原子、ヒドロキシ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基、ニトロ基、アミノ基、アミド基、カルボキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ホルミル基、シアノ基、アルキル基、シクロアルキル基、アラルキル基又はアリール基を表し、
Ｒ ^５ は、アルキルオキシカルボニル基、アリールオキシカルボニル基、アシル基、アルキルスルホニル基又はアリールスルホニル基を表し、
Ｒ ^９ は、ハロゲン原子、ヒドロキシ基、アルコキシ基、アラルキルオキシ基、アリールオキシ基、ニトロ基、アミノ基、アミド基、カルボキシ基、アルキルオキシカルボニル基、アリールオキシカルボニル基、ホルミル基、シアノ基、アルキル基、シクロアルキル基、アラルキル基又はアリール基を表す。
［９］
前記色素が蛍光色素である項１乃至８の何れか１項に記載の粉体。
［１０］
項１乃至９の何れか１項に記載の粉体と少なくとも１種類の液とを含む塗工液。
［１１］
ポリビニルアルコールを更に含む項１０に記載の塗工液。
［１２］
項１乃至９の何れか１項に記載の粉体を含む硬化膜。
［１３］
ポリビニルアルコールを更に含む項１２に記載の硬化膜。
［１４］
基材と、前記基材上に項１２又は１３に記載の硬化膜とを備えた積層体。 As shown in Table 2, the laminates of Test Examples 20 to 35 produced different color changes than the laminate of Test Example 36. Moreover, the laminates of Test Examples 37 and 38 did not emit light both before and after applying the mechanical stimulus. In the laminate of Test Example 39, since the indolylbenzothiadiazole derivative was dissolved in the polyvinyl acetate, the emission color did not change before and after the application of the mechanical stimulus.
The following is an additional description of the invention described in the original claims.
[1]
A powder that emits light when irradiated with excitation light,
an indolylbenzothiadiazole derivative whose emission spectrum is reversibly changed by mechanical stimulation;
a dye whose emission spectrum and absorption spectrum at least partially overlap with the indolylbenzothiadiazole derivative changed by the mechanical stimulation;
powder containing
[2]
Item 2. The powder according to Item 1, wherein the maximum emission wavelength changes by 40 nm or more due to the mechanical stimulation.
[3]
The mechanical stimulus causes a change from a luminescence state in which light of a first color is emitted under irradiation with the excitation light to a luminescence state in which light of a second color different from the first color is emitted under irradiation with the excitation light. The powder according to item 1 or 2.
[4]
Item 3. The powder according to Item 1 or 2, which changes from a luminescent state in which light is emitted under irradiation with the excitation light to a non-light-emitting state in which light is not emitted under irradiation with the excitation light by the mechanical stimulation.
[5]
5. The powder according to any one of Items 1 to 4, wherein the dye has a maximum absorption wavelength of 500 nm or more.
[6]
Item 6. The powder according to any one of items 1 to 5, wherein the amount of the dye is in the range of 0.001 parts by mass or more and less than 100 parts by mass with respect to 100 parts by mass of the indolylbenzothiadiazole derivative.
[7]
7. The powder according to any one of items 1 to 6, which satisfies the following formula (1).
J _after /J _before >1 (1)
In formula (1), J _after is represented by the following formula (2), J _before is represented by the following formula (3), and Iλ ^D (λ) _after imparts the mechanical stimulus to the indolylbenzothiadiazole derivative. Iλ ^D (λ) _before is the emission spectrum normalized by the area immediately after applying the mechanical stimulus to the indolylbenzothiadiazole derivative, and ε _A (λ ) is the molar extinction coefficient of the dye and λ is the wavelength.

[8]
8. The powder according to any one of Items 1 to 7, wherein the indolylbenzothiadiazole derivative is represented by the following general formula (4).

In formula (4),
R ¹ to R ⁴ and R ⁶ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amino group, an amido group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a formyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group;
R ⁵ represents an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group,
R9 is a halogen atom, hydroxy group, alkoxy group ^, aralkyloxy group, aryloxy group, nitro group, amino group, amido group, carboxy group, alkyloxycarbonyl group, aryloxycarbonyl group, formyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group or aryl group.
[9]
Item 9. The powder according to any one of Items 1 to 8, wherein the dye is a fluorescent dye.
[10]
A coating liquid comprising the powder according to any one of Items 1 to 9 and at least one kind of liquid.
[11]
11. The coating liquid according to Item 10, further comprising polyvinyl alcohol.
[12]
A cured film containing the powder according to any one of Items 1 to 9.
[13]
Item 13. The cured film according to Item 12, further comprising polyvinyl alcohol.
[14]
A laminate comprising a substrate and the cured film according to Item 12 or 13 on the substrate.

DESCRIPTION OF SYMBOLS 1... Fluorescence spectrum, 2... Fluorescence spectrum, 3... Absorption spectrum, 4... Fluorescence spectrum, 5... Laminate, 6... Base material, 7... Cured film, 7a... Site to which mechanical stimulation was applied, 15... Laminate , 16 -- Overcoat layer.

Claims (10)

An indolylbenzothiadiazole derivative, which is a powder that emits light when irradiated with excitation light and whose emission spectrum is reversibly changed by mechanical stimulation, and the emission spectrum and absorption of the indolylbenzothiadiazole derivative that is changed by the mechanical stimulation. a powder comprising a pigment whose spectra are at least partially overlapping;
and polyvinyl alcohol ,
A cured film in which the indolylbenzothiadiazole derivative is represented by the following general formula (4) .

In formula (4),
R ¹ to R ⁴ and R ⁶ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amino group, an amido group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a formyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group;
R ⁵ represents an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group,
R9 is a halogen atom, hydroxy group, alkoxy group ^, aralkyloxy group, aryloxy group, nitro group, amino group, amido group, carboxy group, alkyloxycarbonyl group, aryloxycarbonyl group, formyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group or aryl group. 2. The cured film according to claim 1, wherein the powder changes the maximum emission wavelength by 40 nm or more due to the mechanical stimulation. The powder emits light of a second color different from the first color under irradiation of the excitation light from a luminescence state in which light of a first color is emitted under irradiation of the excitation light by the mechanical stimulation. 3. The cured film according to claim 1, which changes to a luminous state. 3. The powder according to claim 1 or 2, wherein the powder changes from a luminescent state in which light is emitted under irradiation with the excitation light to a non-light-emitting state in which light is not emitted under irradiation with the excitation light by the mechanical stimulation. cured film. 5. The cured film according to any one of claims 1 to 4, wherein the dye has a maximum absorption wavelength of 500 nm or more. 6. The cured film according to any one of claims 1 to 5, wherein the amount of the dye is in the range of 0.001 parts by mass or more and less than 100 parts by mass with respect to 100 parts by mass of the indolylbenzothiadiazole derivative. The cured film according to any one of claims 1 to 6, which satisfies the following formula (1).
J _after /J _before >1 (1)
In formula (1), J _after is represented by the following formula (2), J _before is represented by the following formula (3), and I _λ ^D (λ) _after is the mechanical stimulus applied to the indolylbenzothiadiazole derivative. is the emission spectrum normalized by the area immediately after the application, I _λ ^D (λ) _before is the emission spectrum normalized by the area before the mechanical stimulation is applied to the indolylbenzothiadiazole derivative, and ε _A (λ) is the molar extinction coefficient of the dye and λ is the wavelength.

8. The cured film according to any one of claims 1 to 7 , wherein the dye is a fluorescent dye. A laminate comprising a substrate and the cured film according to any one of claims 1 to 8 provided on the substrate. An indolylbenzothiadiazole derivative, which is a powder that emits light when irradiated with excitation light and whose emission spectrum is reversibly changed by mechanical stimulation, and the emission spectrum and absorption of the indolylbenzothiadiazole derivative that is changed by the mechanical stimulation. a powder comprising a pigment whose spectra are at least partially overlapping;
at least one liquid;
and polyvinyl alcohol ,
A coating liquid in which the indolylbenzothiadiazole derivative is represented by the following general formula (4) .

In formula (4),
R ¹ to R ⁴ and R ⁶ to R ⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an alkoxy group, an aralkyloxy group, an aryloxy group, a nitro group, an amino group, an amido group, a carboxy group, an alkyloxycarbonyl group, an aryloxycarbonyl group, a formyl group, a cyano group, an alkyl group, a cycloalkyl group, an aralkyl group or an aryl group;
R ⁵ represents an alkyloxycarbonyl group, an aryloxycarbonyl group, an acyl group, an alkylsulfonyl group or an arylsulfonyl group,
R9 is a halogen atom, hydroxy group, alkoxy group ^, aralkyloxy group, aryloxy group, nitro group, amino group, amido group, carboxy group, alkyloxycarbonyl group, aryloxycarbonyl group, formyl group, cyano group, alkyl group, cycloalkyl group, aralkyl group or aryl group.

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