JP2003176419A - Thermoresponsively fading colored composition and thermoresponsively fading colored element using the same, and method for detecting thermal history - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a thermoresponsively fading colored composition readily fading a color without causing image defects as a result of dry development processing, to provide a thermoresponsively fading colored element having thermoresponsively fading a colored layer comprising the composition, and to provide a method for detecting thermal history by using such a composition or element. <P>SOLUTION: This thermoresponsively fading colored composition exhibits a color at a temperature below its fading initiation temperature (T), substantially fades the color at a temperature higher than the temperature T, and does not restore its original color even if its temperature is reverted again below the temperature T after the fading occurred once. The composition contains a polymer having the fading initiation temperature T of 60-200°C and a glass transition temperature (Tg) of 60-200°C. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a printed matter that can be recycled by heat treatment, and can be suitably used for detecting the thermal history of electronic devices, food products, and the like, and a thermally responsive decolorizable composition. The present invention relates to a thermoresponsive decolorizable coloring element using a coloring composition and a method for detecting heat history.

[0002]

2. Description of the Related Art Recently, with the spread of OA equipment and the rapid progress of IT technology, documents are flooded in offices, and the increased disposal of paper waste has become a serious social problem. It is also attracting attention as an environmental issue such as the protection of forest resources.
Against this background, particularly in the development of recycling technology for copy paper, a hydrolyzable toner, a toner that is decolorized by light, and the like are disclosed in JP-A Nos. 7-120975 and 7-301952.
No., etc. Toner that can be decolorized by heating
Takayama et al., "Polymer Preprints, Japan" Vol. 47, No. 9
(1998), page 2063, etc. Furthermore, a method has also been proposed in which a color-forming component composed of an electron-donating color-forming organic compound and a phenolic substance or other acidic substance is heat-erased with a decolorizer (Japanese Patent Publication No. 57-59079). As described above, various erasing methods have been proposed, but the dry method is preferable from the viewpoint of easiness of processing.

Several methods have been proposed for decoloring by dry processing, but the main ones are (1) dyes that decolorize by heat (US Pat. Nos. 3,769,019 and 3,821,001).
No. 4,033,948, No. 4,088,497, No. 4,153,46
No. 3 and No. 4,283,487, JP-A Nos. 52-139136 and 53-13.
2334, 54-56818, 57-16060 and 59-182436
No.), or a dye which is decolored by a corrosive gas generated from salt when heated (US Pat. No. 4,347,401), (2) a method in which a carbanion generator by heat and a dye coexist to decolor when heated (U.S. Patent No. 5,135,842,
5,258,274, 5,314,795, 5,324,627 and
5,384,237, European Patent 605286, JP-A-6-222504 and 7-199409), (3) Use a dye that forms a colored state in the form of a leuco dye and an acid that is volatilized or decomposed by heating. Method (JP-A-10-16410 and JP-A-10-28705
No. 5), (4) o-nitroallylidene dye or o-nitro-o-azaallylidene dye (US Pat. No. 3,984,248 and Japanese Patent Laid-Open No.
4-17833), NO bond cleavable dye (US Pat. No. 3,770,45)
No. 1), a chrominium type cyanine dye (JP-A-2-229864
No.), an anionic dye containing an iodonium salt as a counter ion (JP-A-59-164549), and the like, and (5) a photosensitive halogen-containing compound (JP-A-57-207).
34 and JP-A-57-68831), azides (JP-A-63-146)
No. 028), a ketone-based sensitizer (Japanese Patent Laid-Open No. 50-10618), a mesoionic compound (US Pat. No. 4,548,895) or an iodonium compound (US Pat. No. 4,701,402), and the above compound is irradiated with light and / or heated. There is a method in which a dye that reacts with the resulting activated species or that interacts with the above-mentioned compound in the excited state to decolorize is made to coexist.

The above methods (1) to (3) are simple since they can erase the color when heated. However, in these methods, a decoloring reaction occurs during storage, and there is a possibility that the function cannot be expressed when necessary. It has also been clarified that the gas may grow into bubbles and cause image defects if a reaction involving the generation of gas is used during heating.

On the other hand, the methods (4) and (5) for erasing with light alleviate the above problems, but since a large amount of radiation is required for erasing, there is a possibility of photodiscoloration. Further, there is a drawback that the processing takes time.

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to solve the above-mentioned drawbacks of the art and to provide a thermoresponsive decolorizable coloring composition which is easily decolorized by a dry treatment, and such a thermoresponsive decolorizable coloring composition. PROBLEM TO BE SOLVED: To provide a thermoresponsive decolorizable coloring element having a thermoresponsive decolorizable colored layer containing a substance, and to provide a method for detecting a thermal history using the thermoresponsive decolorizable coloring composition or the thermoresponsive decolorizable coloring element. It is to be.

[0007]

Means for Solving the Problems As a result of earnest research in view of the above problems, the present inventors have found that by blending a polymer having a glass transition temperature (Tg) of 60 to 200 ° C. in a decolorizable coloring composition, 6
Although it is colored at a temperature lower than the decolorization start temperature (T) of 0 to 200 ° C, it is substantially decolored at a temperature higher than the decolorization start temperature (T),
It was discovered that a thermo-responsive decolorizable coloring composition that does not recolor even if it is once decolored and then returned to below the decolorization start temperature (T) is reached, and the present invention was conceived.

That is, although the thermoresponsive decolorizable coloring composition of the present invention is colored at a temperature lower than the decolorization start temperature (T),
Substantially erasing at a temperature of the erasing start temperature (T) or higher, once erasing, even if the temperature is returned to below the erasing start temperature (T) again, the erasing does not resume, and the erasing start temperature (T) Of 60 to 200 ° C. and a polymer having a glass transition temperature (Tg) of 60 to 200 ° C. are contained.

The thermoresponsive decolorizable coloring composition of the present invention preferably contains at least an electron-donating color-developing organic compound and an acidic compound, and the acidic compound is preferably a phenolic compound. Further, the heat-responsive decolorizable coloring composition of the present invention preferably contains a hydrophilic binder. The polymer is preferably dispersed particles having an average particle size of 0.01 μm to 1 μm.

The thermoresponsive decolorizable color element of the present invention is characterized in that a thermoresponsive decolorizable color layer comprising the above-mentioned thermoresponsive decolorizable color composition is coated on a support.

The method for detecting heat history of the present invention comprises applying the above-mentioned heat-responsive decolorizable coloring composition to a subject and measuring the coloring density of the heat-responsive decolorizable coloring composition to measure the heat history of the subject. Is detected. Another method for detecting a thermal history of the present invention is to install the above-mentioned thermoresponsive decolorizable coloring element in the vicinity of a subject and measure the coloring concentration of the thermoresponsive decolorizable coloring composition to measure the heat of the subject. It is characterized by detecting history.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoresponsive decolorizable coloring composition of the present invention is colored at 25 ° C., but it irreversibly decolors at a temperature of decoloration starting temperature (T) or higher, It contains a polymer having a (T) of 60 to 200 ° C and a glass transition temperature (Tg) of 60 to 200 ° C. Hereinafter, the thermoresponsive decolorizable coloring composition of the present invention, the thermoresponsive decolorizable coloring element using the same, and the method for detecting the thermal history of the test object will be described in detail.

In the present specification, "decoloration start temperature (T)"
Is defined as the temperature at which the density reaches an intermediate level between the coloring density at 25 ° C and the basal coloring density (equilibrium coloring density) at which the coloring density does not decrease even if the temperature is further raised. Specifically, it is a temperature at which the light absorption coefficient at the maximum absorption wavelength in the visible wavelength region (400 nm to 700 nm) becomes an intermediate value between the light absorption coefficient at 25 ° C and the light absorption coefficient in the ground state. In the present specification, "decoloring" means that the coloring density is 40% or less of the coloring density at 25 ° C. In addition, “does not recolor” means that the color density at 25 ° C is 4% even if the temperature is less than the decoloring start temperature (T) after decoloring.
It means that the color density does not return to more than 0%.

[1] Thermoresponsive decolorizable coloring composition The thermoresponsive decolorizable colored composition has a glass transition temperature (Tg) of 60 to
It is essential to contain a polymer at 200 ° C. The polymer is preferably dispersed particles having an average particle size of 0.01 μm to 1 μm. The heat-responsive decolorizable coloring composition preferably contains at least an electron-donating color-developing organic compound and an acidic compound, and the acidic compound is preferably a phenolic compound. The heat-responsive decolorizable coloring composition may further contain a decoloring agent.

(A) Polymer When heated to a temperature higher than the glass transition temperature (Tg) of the polymer, the interaction between the electron-donating color-developing compound and the developer is disturbed, so that the thermoresponsive decoloring property The coloring composition disappears. Even if the decolored colored composition is brought to a temperature lower than Tg again, the interaction between the electron-donating color developing compound and the developer is hindered by the solidification of the polymer having a glass transition temperature (Tg) of 60 to 200 ° C. Since the coloring composition is fixed in the open state, the coloring composition does not recolor. As described above, the polymer used in the present invention has an action of fixing the reversible decoloring / developing change caused by the electron-donating color developing compound and the developer on the decoloring side (maintaining the decoloring state). In order to exert this effect effectively, the glass transition temperature (Tg) of the polymer is lower than the processing temperature, but it is preferable that it is as close as possible to it, specifically, Tg is 60 to 200 ° C.
The polymer is used.

The polymer itself may also serve as the decoloring agent. In this case, since the polymer needs to maintain an independent dispersed state before the temperature rise, a polymer in the form of dispersed particles, that is, a polymer latex is preferable. Here, the “polymer latex” is a dispersion of a water-insoluble hydrophobic polymer in the form of fine particles in an aqueous medium. As a dispersed state, the polymer is emulsified in a dispersion medium, emulsion-polymerized, micelle-dispersed, having a partially hydrophilic structure in the polymer molecule, molecular chains themselves are dispersed in a molecular form, etc. , Either is fine. The preferred dispersion state is emulsified in a dispersion medium, emulsion-polymerized one, and one in which the molecular chain itself has a molecular structure and has a partially hydrophilic structure in the polymer molecule. It is polymerized. For details on polymer latex, see “Synthetic Resin Emulsion” edited by Taira Okuda and Hiroshi Inagaki.
(Published by Kobunshi Kogyokai, 1978), Soichi Muroi, "Chemistry of Polymer Latex" (Kobunshi Kobunkai, 1970).

Examples of polymers used for the polymer latex include acrylic resin, vinyl chloride resin, vinylidene chloride resin, polyolefin resin, condensation type polymer resin (polyurethane resin, polyester resin, polyamide resin, polyurea resin, polycarbonate resin) or these. Copolymers of Among them, acrylic resins using vinyl monomers, vinyl chloride resins, vinylidene chloride resins, polyolefin resins or copolymers thereof are preferable, and acrylic resins are more preferable.

The polymer may be a linear, branched or crosslinked polymer. Further, it may be a so-called homopolymer composed of a single type of repeating unit or a copolymer composed of a plurality of types of repeating units. The number average molecular weight of the polymer is advantageously 5,000 to 1,000,000, 10,000 to 100,00
0 is even more advantageous. If the number average molecular weight is less than 5,000,
When the thermoresponsive decolorizable composition of the present invention is used in the colored layer,
The layer strength tends to be inadequate. Further, when it exceeds 100,000, the film-forming property may be deteriorated, and when the composition is used as an ink, there is a problem in ejection property.

The average particle size of the polymer fine particles in the polymer latex is preferably 0.01 to 1 μm, more preferably 0.01 to 0.5 μm, still more preferably 0.02 to 0.3 μm. The particle size distribution is not particularly limited, and may have a wide particle size distribution or a monodisperse particle size distribution.

The polymer particles in the polymer latex have a glass transition temperature (Tg) of 60 ° C to 200 ° C, preferably 90 ° C to 150 ° C. Tg can be determined using a scanning differential thermal analyzer (DSC). That is, a 10 mg sample in a nitrogen stream at a temperature rising rate of 20 ° C / min to 300 ° C.
It is calculated from the arithmetic mean of the temperature at which the temperature starts to deviate from the baseline and the temperature at which the temperature returns to a new baseline when the temperature is raised again at 20 ° C / min after being rapidly cooled to room temperature.

The polymer latex may be a so-called core-shell type latex in which the entire composition is substantially uniform or the central portion and the outer portion have different compositions. In order to fully utilize the characteristics of the core-shell type latex, it is preferable that the core part and the shell part have different Tg or degree of crosslinking. When the Tg is different, the Tg of the core part and the Tg of the shell part are preferably different by 30 ° C. or more. The Tg of the core part may be higher or lower than the Tg of the shell part, but is preferably lower. Tg of core is 60 ℃ ～ 20
0 degreeC is preferable and 90 degreeC-150 degreeC is more preferable. Different resins can be used for the core and the shell to change the Tg of the core and the shell. When the core portion and the shell portion have different degrees of crosslinking, it is preferable that one is crosslinked and the other is uncrosslinked, and it is more preferable that the core portion is crosslinked and the shell portion is uncrosslinked. The weight ratio of the monomers constituting the core portion and the shell portion is arbitrary, but the core portion / shell portion is preferably 20/80 to 80/20, and more preferably 50/50 to, for good film-forming property. 70/30.

The vinyl polymer latex will be described below as an example. The structure of the polymer can be a homopolymer or a freely combined copolymer of any monomers selected from the monomer groups exemplified below. The monomer unit that can be used is not particularly limited, and any monomer can be used as long as it can be polymerized by an ordinary radical polymerization method.

(A) Monomers (1) Olefins: ethylene, propylene, isoprene, butadiene, vinyl chloride, vinylidene chloride, 6-hydroxy-1-hexene, cyclopentadiene, 4-pentenoic acid, methyl 8-nonenate, Vinylsulfonic acid, trimethylvinylsilane, trimethoxyvinylsilane, butadiene, pentadiene, isoprene, 1,4-divinylcyclohexane, 1,2,5-trivinylcyclohexane, etc.

(2) α, β-unsaturated carboxylic acids and salts thereof: acrylic acid, methacrylic acid, itaconic acid, maleic acid, sodium acrylate, ammonium methacrylate, potassium itaconic acid, etc.

(3) α, β-unsaturated carboxylic acid esters:
Alkyl acrylate (methyl acrylate, ethyl acrylate, t-butyl acrylate, adamantyl acrylate, etc.), substituted alkyl acrylate (2-chloroethyl acrylate, benzyl acrylate, 2-cyanoethyl acrylate, allyl acrylate, etc.), alkyl methacrylate (methyl methacrylate, t-) Butyl methacrylate, adamantyl methacrylate, etc., substituted alkyl methacrylate (2-hydroxyethyl methacrylate, glycidyl methacrylate, glycerin monomethacrylate, 2-acetoxyethyl methacrylate, tetrahydrofurfuryl methacrylate, 2-methoxyethyl methacrylate, ω-methoxy polyethylene glycol methacrylate (poly Number of moles of oxyethylene added = 2
~ 100), polyethylene glycol monomethacrylate (polyoxyethylene addition mole number = 2 to 100), polypropylene glycol monomethacrylate (polyoxypropylene addition mole number = 2 to 100), 2-carboxyethyl methacrylate, 3-sulfopropyl Methacrylate, 4-oxysulfobutylmethacrylate, 3-trimethoxysilylpropylmethacrylate, allylmethacrylate, etc., unsaturated dicarboxylic acid derivatives (monobutyl maleate, dimethyl maleate, monomethyl itaconate, dibutyl itaconate, etc.), polyfunctional esters Kinds (ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,4-cyclohexane diacrylate,
Pentaerythritol tetramethacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, dipentaerythritol pentamethacrylate, pentaerythritol hexaacrylate, 1,2,4-
Cyclohexane tetramethacrylate etc.) etc.

(4) Amides of α, β-unsaturated carboxylic acid:
Acrylamide, methacrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-methyl-N-hydroxyethylmethacrylamide, N-tert-butylacrylamide, N-tert-octylmethacrylamide, N-cyclohexylacrylamide, N-phenylacrylamide ,
N- (2-acetoacetoxyethyl) acrylamide, N-acryloylmorpholine, diacetoneacrylamide, itaconic acid diamide, N-methylmaleimide, 2-acrylamido-2-methylpropanesulfonic acid, methylenebisacrylamide, dimethacryloylpiperazine and the like.

(5) Styrene and its derivatives: Styrene,
Vinyltoluene, p-tert-butylstyrene, vinylbenzoic acid, methyl vinylbenzoate, α-methylstyrene, p-chloromethylstyrene, vinylnaphthalene, p-hydroxymethylstyrene, p-styrenesulfonic acid sodium salt,
p-Styrene sulfinic acid potassium salt, 1,4-divinylbenzene, 4-vinylbenzoic acid-2-acryloylethyl ester and the like.

(6) Vinyl ethers: methyl vinyl ether, butyl vinyl ether, methoxyethyl vinyl ether and the like.

(7) Vinyl esters: vinyl acetate, vinyl propionate, vinyl benzoate, vinyl salicylate,
Chlorovinyl acetate etc.

(8) Other monomers: N-vinylpyrrolidone, 2-vinyloxazoline, 2-isopropenyloxazoline, divinylsulfone and the like.

(B) Specific Examples of Polymers Specific examples (P-1 to 29) of the polymers in the polymer latex that can be used in the present invention are listed below, and the polymers of the polymer latex are these specific examples. It is not limited to the example. In the case of a copolymer, the ratio in parentheses represents the mass ratio of the monomers.

P-1) Poly t-butyl methacrylate: Tg 11
8 ℃ P-2) Polyphenyl methacrylate: Tg 110 ℃ P-3) Polymethyl methacrylate: Tg 105 ℃ P-4) Polyacrylonitrile: Tg 125 ℃ P-5) Polypentachlorophenyl acrylate: Tg 147
℃ P-6) Polyadamantyl methacrylate: Tg 140 ℃ P-7) Poly t-butyl methacrylamide: Tg 160 ℃ P-8) Polystyrene: Tg 100 ℃ P-9) Polymethacrylonitrile: Tg 120 ℃ P-10 ) Acrylonitrile-methacrylic acid copolymer (95:
5): Tg 123 ℃ P-11) Methyl methacrylate-acrylic acid copolymer (9
7: 3): Tg 104 ° C P-12) Methacrylonitrile-acrylic acid copolymer (95:
5): Tg 104 ° C P-13) Methyl methacrylate-acrylic acid copolymer (9
5: 5): Tg 100 ° C P-14) Polyvinyl chloride: Tg 93 ° C P-15) Acrylonitrile-ethyl acrylate copolymer (70:30): Tg 68 ° C P-16) Polyethylmethacrylate: Tg 65 ° C P-17) Polyisopropylmethacrylate: Tg 81 ° C P-18) Polyisobutylchloroacrylate: Tg 90 ° C P-19) Isopropylmethacrylate-acrylic acid copolymer (96: 4): Tg 80 ° C P-20) Acrylonitrile- Butyl acrylate copolymer (80:20): Tg 79 ° C P-21) adamantyl methacrylate-methyl methacrylate-acrylic acid copolymer (60: 35: 5): Tg 110 ° C P-22) methacrylonitrile-polyethylene glycol Methacrylic acid ester of monomethyl ether (23 repeating units of ethyleneoxy chain) -acrylic acid copolymer (90: 8: 2): Tg 104 ℃ P-23) Methyl methacrylate-divinylbenzene copolymer (97: 3): Tg 101 ° C P-24) Methyl methacrylate-styrene sulfonic acid copolymer (92: 8): Tg 105 ° C P-25) Methyl methacrylate-ethylene glycol dimethacrylate copolymer (95: 5): Tg 101 ° C P-26 ) (Core part) polystyrene-divinylbenzene copolymer (95: 5): Tg 100 ° C / (shell part) methyl methacrylate-methacrylic acid copolymer (97: 3): Tg 101 ° C P-27) (core part) ) Poly 4-chlorostyrene: Tg 115 ° C /
(Shell part) acrylonitrile-butyl acrylate-
Methacrylic acid copolymer (80: 17: 3): Tg 81 ° C P-28) (Core part) Polystyrene: Tg 100 ° C / (shell part) Methylmethacrylate-methacrylic acid copolymer (9
7: 3): Tg 101 ℃ P-29) (Core part) Poly 4-butylstyrene: Tg 7 ℃ /
(Shell part) Methyl methacrylate-methacrylic acid copolymer (97: 3): Tg 101 ° C

(B) Electron-donating color-developing organic compound The electron-donating color-developing organic compound which is preferably used in the invention is known per se and is not limited to a particular kind. Known electron-donating color-developing organic compounds are described in "Dyes and Chemicals" by Moriga and Yoshida (Chemicals Industry Association, 1964), Volume 9, p. 84,
R. Garner, "New Edition Dye Handbook" (Maruzen, 1970), p.242.
"Reports on the Progress of Appl. Chem." (1971
56), 199 pages, "Dyes and Chemicals" (Chemical Industry Association, 1
974), 19 pages, 230 pages, "Coloring materials" (1989), 62 volumes, 28
P.8, "Dyeing Industry" Vol. 32, p. 208, etc.

The electron-donating color-forming organic compound can be structurally classified into several systems. Preferred systems used in the present invention include diarylphthalide systems, fluorane systems,
Examples thereof include indolylphthalide type, acylleucoazine type, leuco auramine type, spiropyran type, rhodamine lactam type, triarylmethane type, chromene type and the like. Specific examples of the electron-donating color-developing organic compound that can be used in the present invention are shown below by structural formulas.

(A) Diarylphthalide compound

[Chemical 1]

(B) Fluoran compound

[Chemical 2]

[0037]

[Chemical 3]

[0038]

[Chemical 4]

[0039]

[Chemical 5]

(C) Indolylphthalide compound

[Chemical 6]

[0041]

[Chemical 7]

[0042]

[Chemical 8]

(D) Acyl leucoazine compound

[Chemical 9]

(E) Leuco auramine compound

[Chemical 10]

(F) Spiropyran compound

[Chemical 11]

(G) Rhodamine lactam compound

[Chemical 12]

(H) Triarylmethane compound

[Chemical 13]

(I) Chromene compound

[Chemical 14]

(J) Other compounds

[Chemical 15]

When a laser light source such as a semiconductor laser, which is widely used at present, is used, an electron-donating color-forming organic compound which develops a color in a wavelength region longer than 620 nm can be used. Among such electron-donating color-developing organic compounds, 2,6-diaminofluorane compounds having a cyclic structure at the 2- and 3-positions are disclosed in JP-A Nos. 3-14878, 3-244587 and 4-1.
No. 73288, fluoran compounds having a p-phenylenediamine moiety as a substituent are described in JP-A-61-284485 and JP-A-3-239587, and thiofluorane compounds are described in JP-A-52-106873. No. 3,3-
Bis (4-substituted aminophenyl) azaphthalide compounds are described in JP-A Nos. 5-139026 and 5-179151, and phthalide compounds having a vinyl group are disclosed in JP-B-58-5940 and 58-
No. 27825 and 62-24365, fluorene compounds are described in JP-A-63-94878 and JP-A-3-202386, sulfonylmethane compounds having a vinyl group are JP-A-60- 230890 and 60-231766, and compounds having a phenothiazine or phenoxazine ring are described in JP-A-63-199268. Specific examples of the electron-donating color-developing organic compound preferably used in the present invention are shown below.

[0051]

[Chemical 16]

[0052]

[Chemical 17]

[0053]

[Chemical 18]

[0054]

[Chemical 19]

[0055]

[Chemical 20]

The above specific examples are a part of the electron donating color developing organic compound, and the electron donating color developing organic compound used in the present invention is not limited to these. The electron-donating color-developing organic compound may be used alone or in combination of two or more.

(C) Acidic Compound The acidic compound functions as a color developing agent, and specifically develops the electron-donating color-developing organic compound described above. The acidic compound is preferably a phenolic compound. The acidic compound may be used alone or in combination of two or more. For example, a phenolic compound and an acidic compound other than the phenolic compound can be used in combination. Hereinafter, the phenolic compound and the acidic compound other than the phenolic compound will be described in detail.

(A) Phenolic Compounds Phenolic compounds include monohydric phenols, dihydric phenols and polyhydric phenols, and alkyl groups, aryl groups, acyl groups, alkoxycarbonyl groups, carboxy groups and Its ester, amide group,
Some have halogens and the like, and there are bis type and tris type phenols.

Preferable examples of the phenol-based developer include phenol, o-cresol, tert-butylphenol, nonylphenol, n-octylphenol, n-dodecylphenol, n-stearylphenol, p-chlorophenol, p-bromophenol, o-Phenylphenol, n-butyl p-hydroxybenzoate, n-octyl p-hydroxybenzoate, n-dodecyl p-hydroxybenzoate, resorcin, dodecyl gallate, 2,2-bis (4'-hydroxyphenyl) Propane, 4,4'-dihydroxydiphenyl sulfone, 1,1-bis (4'-hydroxyphenyl) ethane, 2,2-
Bis (4'-hydroxy-3-methylphenyl) propane, bis
(4'-hydroxyphenyl) methane, bis (4-hydroxyphenyl) sulfide, 1-phenyl-1,1-bis (4'-hydroxyphenyl) ethane, 1,1-bis (4'-hydroxyphenyl)
-3-methylbutane, 2,2-bis (4'-hydroxyphenyl) butane, 2,2-bis (4'-hydroxyphenyl) ethyl propionate, 2,2-bis (4'-hydroxyphenyl) -4 -Methylpentane, 1,1-bis (4'-hydroxyphenyl) -2-methylpropane, 2,2-thiobis (6-tert-butyl-3-methylphenol), 2,2-bis (4'-hydroxy (Phenyl) hexafluoropropane, 1,1-bis (4'-hydroxyphenyl) n-pentane, 1,1-bis (4'-hydroxyphenyl) n-hexane, 1,1-bis (4'-hydroxyphenyl) n-heptane, 1,1
-Bis (4'-hydroxyphenyl) n-octane, 1,1-bis
(4'-hydroxyphenyl) n-nonane, 1,1-bis (4'-hydroxyphenyl) n-decane, 1,1-bis (4'-hydroxyphenyl) n-dodecane, 2,2-bis (4 '-Hydroxyphenyl)
n-heptane, 2,2-bis (4'-hydroxyphenyl) n-nonane, 1,1-bis (4'-hydroxyphenyl) -4-methylbutane, 1,1-bis (3'-methyl-4 Examples include'-hydroxyphenyl) n-hexane and the like.

(B) Acidic Compounds Other Than Phenolic Compounds Preferred examples of acidic compounds other than phenolic compounds are boric acid, oxalic acid, maleic acid, tartaric acid, citric acid, succinic acid, benzoic acid, stearic acid, gallic acid. Acid, salicylic acid, 1-hydroxy-2-naphthoic acid, o-hydroxybenzoic acid, m-hydroxybenzoic acid, 2-hydroxy-p-toluic acid, benzenesulfinic acid, anthraquinone-1-
Examples thereof include sulfenic acid. These compounds may have various substituents.

(D) Decoloring Agent The heat-responsive decolorizable coloring composition of the present invention preferably contains a decoloring agent for the purpose of facilitating temperature programmed decolorization. As the decoloring agent, it is preferable to use compounds such as alcohols, esters, ketones, and ethers that act as decoloring agents at high temperatures. Further, polymers and oligomers having these as repeating units are also effective.

(A) Alcohols Specific examples of alcohols include decane 1-ol, undecane 1-ol, lauryl alcohol, tridecane 1-ol, myristyl alcohol, pentadecane 1-ol, cetyl alcohol, heptadecane 1-ol, Stearyl alcohol, octadecane 2-ol, eicosan 1-ol, docosan 1-ol, 6- (perfluoro-7-
Methyloctyl) hexanol, cyclododecanol,
1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,2-cyclododecanediol, sterol compounds (eg cholesterol, stigmasterol, pregnenolone, methylandrostenediol, estradiol benzoate, epiandrostene, stenolone, β- Sitosterol, pregnenolone acetate,
β-cholesterol, 5,16-pregnadien-3β-ol-
20-one, 5α-pregnene-3β-ol-20-one, 5-pregnene-3β, 17-diol-20-one 21-acetate, 5-pregnene-3β, 17-diol-20-one 17-acetate, Five-
Pregnen-3β, 21-diol-20-one 21-acetate, 5
-Pregnene-3β, 17-diol diacetate, locogenin, tigogenin, esmiragenin, hecogenin, diosgenin, etc.), sugars and their derivatives (eg glucose,
Sucrose, etc.), alcohols having a cyclic structure (eg 1,2: 5,6-diisopropylidene-D-mannitol, etc.)
Etc.

(B) Esters The preferred esters used in the present invention are the following (1) to
Broadly divided into (4). (1) Esters having a total carbon number of 10 or more and consisting of a monovalent fatty acid and an aliphatic monohydric alcohol or an alicyclic monohydric alcohol. (2) Polybasic acid esters having a total carbon number of 28 or more, which are composed of an aliphatic divalent or polyvalent carboxylic acid and an aliphatic monohydric alcohol or an alicyclic monohydric alcohol. (3) Esters having a total carbon number of 26 or more and consisting of an aliphatic dihydric or polyhydric alcohol and a monovalent fatty acid. (4) Esters having a total carbon number of 28 or more and consisting of a dihydric alcohol having an aromatic ring and a monovalent fatty acid.

Examples of the esters (1) having a total carbon number of 10 or more and consisting of a monovalent fatty acid and an aliphatic monohydric alcohol or an alicyclic monohydric alcohol include ethyl caprylate,
N-Butyl caprylate, n-octyl caprylate, lauryl caprylate, cetyl caprylate, stearyl caprylate, n-butyl caprate, n-hexyl caprate, myristyl caprate, docosyl caprate, methyl laurate, laurate 2-ethylhexyl, n-decyl laurate, stearyl laurate, ethyl myristate, 3-methylbutyl myristate, 2-methylpentyl myristate, n-decyl myristate, cetyl myristate, stearyl myristate, isopropyl palmitate, palmitate Acid neopentyl, n-nonyl palmitate, n-undecyl palmitate, lauryl palmitate, myristyl palmitate, cetyl palmitate, stearyl palmitate, cyclohexyl palmitate, cyclohexylmethyl palmitate, stearate. Methyl formate, ethyl stearate, n-propyl stearate, n-stearate
Butyl, n-amyl stearate, 2-methylbutyl stearate, n-hexyl stearate, n-heptyl stearate, 3,5,5-trimethylhexyl stearate, n-octyl stearate, 2-ethylhexyl stearate, stearin N-Nonyl acid, n-decyl stearate, n-undecyl stearate, lauryl stearate, n-tridecyl stearate, myristyl stearate, n-pentadecyl stearate, cetyl stearate, stearyl stearate, eicosyl stearate, stearin Acid n-
Docosyl, cyclohexyl stearate, cyclohexylmethyl stearate, oleyl stearate, isostearyl stearate, n- 1,2-hydroxystearate
Butyl, n-methyl behenate, n-ethyl behenate, n-propyl behenate, isopropyl behenate, n-butyl behenate, isobutyl behenate, 2-methylbutyl behenate, n-amyl behenate, behenic acid Neopentyl, n-hexyl behenate, 2-methylpentyl behenate, n-heptyl behenate, 2-ethylhexyl behenate, n-nonyl behenate, myristyl behenate, n-undecyl behenate, lauryl behenate, N-tridecyl behenate, myristyl behenate,
Examples thereof include n-pentadecyl behenate, cetyl behenate, stearyl behenate, and behenyl behenate.

Examples of polybasic acid esters (2) having a total carbon number of 28 or more, which comprises an aliphatic divalent or polyvalent carboxylic acid and an aliphatic monohydric alcohol or an alicyclic monohydric alcohol, include oxalic acid. Dimyristyl, dicetyl oxalate, dilauryl malonate, dicetyl malonate, distearyl malonate, dilauryl succinate, dimyristyl succinate, dicetyl succinate, distearyl succinate, dilauryl adipate, diundecyl adipate, dilauryl adipate, adipate Di n-tridecyl, dimyristyl adipate, dicetyl adipate, distearyl adipate, di n-docosyl adipate, di n-decyl azelate, dilauryl azelate, di n-tridecyl azelate, di n-nonyl sebacate, Dimyristyl sebacate, distearyl sebacate, 1,18- Kutadecyl methylene dicarboxylic acid di-n-pentyl, 1,18-octadecyl methylene dicarboxylic acid di-n-octyl, 1,18-octadecyl methylene dicarboxylic acid di (cyclohexylmethyl), 1,18-octadecyl methylene dicarboxylic acid dineopentyl, 1,18 -Octadecyl methylene dicarboxylic acid-di n-hexyl, 1,18-octadecyl methylene dicarboxylic acid-di n-heptyl, 1,18-
Octadecyl methylene dicarboxylic acid-di n-octyl and the like can be mentioned.

Examples of the esters (3) having a total carbon number of 26 or more and consisting of an aliphatic dihydric or polyhydric alcohol and a monohydric fatty acid include ethylene glycol dimyristate, ethylene glycol dipalmitate, ethylene glycol didiamine. Stearate, propylene glycol dilaurate, propylene glycol dimyristate, propylene glycol dipalmitate, butylene glycol distearate,
Hexylene glycol dilaurate, hexylene glycol dimyristate, hexylene glycol dipalmitate, hexylene glycol distearate, 1,5-pentanediol distearate, 1,2,6-hexanetriol-dimyristate, pentaerythritol tri Myristate, pentaerythritol tetralaurate, 1,4-
Examples thereof include cyclohexanediol didecyl, 1,4-cyclohexanediol dimyristyl, 1,4-cyclohexanediol distearyl, dilaurate of 1,4-cyclohexanedimethanol, and dimyristate of 1,4-cyclohexanedimethanol.

Examples of the esters (4) having a total carbon number of 28 or more and composed of a dihydric alcohol having an aromatic ring and a monovalent fatty acid include xylene glycol dicaprate, xylene glycol di-n-undecanoate, xylene glycol dilaurate, Examples thereof include xylene glycol dimyristate, xylene glycol dipalmitate, and xylene glycol distearate.

(C) Ketones As ketones, it is preferable to use compounds having 10 or more carbon atoms, specifically, decan-2-one, undecane-2-one,
Examples include lauron and stearone.

(D) Ethers Examples of ethers include butyl ether, hexyl ether, diisopropylbenzyl ether, diphenyl ether, dioxane, ethylene glycol dibutyl ether, diethylene glycol dibutyl ether, ethylene glycol diethyl ether, diethylene glycol diethyl ether, ethylene glycol diphenyl ether, etc. Is mentioned.

One of the above decoloring agents may be used,
You may use 2 or more types together. In addition, the stabilizer described below,
In some cases, the above-mentioned polymer may have an alcohol, a ketone, an ester, an ether structure or the like to impart a decoloring effect and no decolorizing agent may be added.

(E) Hydrophilic Binder The hydrophilic binder preferably used in the present invention includes the hydrophilic binders described on pages 71 to 75 of JP-A-64-13546. The hydrophilic binder is preferably transparent or translucent, and specific examples thereof include proteins such as gelatin and gelatin derivatives, cellulose derivatives, natural compounds such as polysaccharides such as starch, gum arabic, dextran and pullulan; polyvinyl alcohol and modified polyvinyl alcohol. (Terminal alkyl modified Poval MP103, M manufactured by Kuraray Co., Ltd.
P203), polyvinylpyrrolidone, polyacrylamide, and other synthetic polymer compounds. Also U.S. Pat.
960,681, JP-A-62-245260 and the like, a super absorbent polymer, that is, a homopolymer of vinyl monomer having -COOM or -SO3M (M is a hydrogen atom or an alkali metal), or the vinyl monomers themselves or other vinyl monomers. Copolymer with vinyl monomer (sodium methacrylate, ammonium methacrylate, Sumika Gel L- manufactured by Sumitomo Chemical Co., Ltd.
5H) can also be used. These hydrophilic binders can be used in combination of two or more. In that case,
The combination of gelatin with other hydrophilic binders is preferred.

Examples of gelatin used as the hydrophilic binder include lime-processed gelatin, acid-processed gelatin, and so-called demineralized gelatin having a reduced content of calcium and the like. The type of gelatin may be selected according to the purpose, and two or more types may be used in combination.

(F) Blending amount of each component (a) Blending amount of polymer In the thermoresponsive decolorizable coloring composition of the present invention, the blending amount of the polymer is 1 part by mass of the electron-donating color developing organic compound. 1 to 1000 parts by mass is preferable, and 5 to 500 parts by mass is more preferable. When the blending amount of the polymer is less than 1 part by mass, the effect of fixing the reversible decoloring color change on the decoloring side is insufficient. When the amount of the polymer compounded exceeds 1000 parts by mass,
It may be difficult to change the decolorized color.

(B) Blending amount of electron-donating color developing compound When the thermoresponsive decolorizable coloring composition of the present invention is used in the coloring layer, the blending amount of the electron donating coloring compound is 0.01 to 10 mmol.
/ M ² is preferable, and 0.05 to 5 mmol / m ² is more preferable.

(C) Amount of Acidic Compound The amount of the acid compound (developing agent) is preferably 0.1 to 10 parts by mass with respect to 1 part by mass of the electron-donating color developing organic compound,
It is more preferably 1 to 4 parts by mass. When the compounding amount of the color developer is less than 0.1 part by mass, coloring due to the interaction between the electron-donating color-developing organic compound and the color developer tends to be insufficient. Further, if the compounding amount of the color developer exceeds 10 parts by mass, it may be difficult to sufficiently inhibit the interaction between the two.

(D) Compounding amount of decoloring agent The compounding amount of the decoloring agent is preferably 0.1 to 100 parts by mass, and more preferably 1 to 10 parts by mass with respect to 1 part by mass of the electron-donating color developing organic compound. When the amount of the decoloring agent is less than 0.1 part by mass, another substance, that is, a stabilizer or a polymer, is required when changing from the colored state to the decolorized state. Further, if the decoloring agent exceeds 100 parts by mass, color development becomes difficult.

(G) Compounding Method The electron-donating color developing compound and the polymer having a glass transition temperature (Tg) of 60 to 200 ° C., which constitute the thermoresponsive decolorizable coloring composition of the present invention, a developer and a decolorizing agent. A colorant or the like may be blended at the same time, or the electron-donating color-forming compound and the color developer may be mixed in advance to develop a color. The polymer is preferably added in the state of an aqueous dispersion. The decoloring agents may be mixed together in advance, or may be added separately from them and mixed at the time of heating. It is considered that at a low temperature, the interaction between the color-developing agent and the decoloring agent strengthens the interaction between the electron-donating color-developing organic compound and the color-developing agent, and the color is developed. However, at high temperature, the three become uniform, and the interaction between the developer and the decolorizer becomes strong and the color disappears.

The compounding method of the electron-donating color developing compound, the color developing agent and the decoloring agent is arbitrary, but as a preferred method, fine particles containing these compounds are dispersed in a hydrophilic binder such as gelatin or PVA. There is a method of making the form. In this case, the particles may be encapsulated.

The electron-donating color-developing compound, the color-developing agent and the decoloring agent may be so-called oligomer-like or polymer-like compounds in which two or more molecules are bonded. A polymer in which the decoloring agent is a polymer and dispersed in an aqueous liquid can also be preferably used. This aqueous dispersion can be prepared by emulsion polymerization or suspension polymerization, or can be prepared by bulk-polymerizing and finely dispersing it in an aqueous solution.

In the present invention, the time from the decoloring start temperature (T) until reaching the equilibrium coloring density (decoloring time) is preferably within 20 seconds, more preferably within 10 seconds. Therefore, the types and amounts of the electron-donating color developing compound, the color developing agent and the decoloring agent are
It is better to choose to meet this criterion.

(H) Stabilizer A stabilizer may be added to the thermoresponsive decolorizable coloring composition of the present invention for the purpose of maintaining the colored state before the treatment. Stabilizers include Research Disclosure (hereinafter RD
No. 17643 (1978) page 25, RD, No. 18716 (197)
9) Photographic anti-fading agents described on page 650 and RD, No 307105 (1989) page 72 are useful. Among them, hindered phenols are preferable. Further, the decoloring inhibitor (stability improving agent) for heat-sensitive recording paper described in "Paper Pulp Technology Times" (March 1995 issue), pages 4 to 5 is also useful.
Of these, a hydroxybisphenol compound, a phenol compound, a 3-hydroxy-2-naphthamide derivative, a thiobenzoic acid derivative, a gallic acid derivative, a hindered phenol derivative, a diphenylpropane derivative, a novolac type epoxy resin and the like are preferable, and a hindered phenol derivative is particularly preferable. .

The method of adding the stabilizer is not particularly limited and is arbitrary, but it is preferable to coexist with the electron-donating color developing compound and the developer in the same fine particles or fine capsules.

[2] Thermoresponsive decolorizable coloring element In the thermoresponsive decolorizable coloring element of the present invention, a thermoresponsive decolorizable colored layer comprising the above thermoresponsive decolorizable composition is coated on a support. I will do it. Two or more dyes may be mixed and used in one colored layer, and for example, three dyes of yellow, magenta and cyan may be mixed and used. Also, two or more colored layers may be provided by coating.

The support used in the present invention is not particularly limited as long as it can withstand the heat treatment temperature. In general, "The Basics of Photographic Engineering-Silver Salt Photo-" edited by The Photographic Society of Japan
Corona, 1979, pp. 223-240, papers, photographic supports such as synthetic polymers (films), and the like.
Specific examples of the material forming the support include polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyvinyl chloride, polystyrene, polypropylene, polyimide, celluloses (triacetyl cellulose, etc.) and the like. These may be used alone or may be used by laminating one side or both sides with polyethylene or the like.

In addition to this, 29 to 31 of JP-A-62-253159
Pages, pages 14 to 17 of JP-A-1-61236, JP-A-63-316848
U.S. Pat. No. 5,001,03
The support described in No. 3 or the like can be used. These supports may be subjected to heat treatment (control of crystallinity and orientation), uniaxial and biaxial stretching (control of orientation), blending of various polymers, surface treatment, etc. in order to improve optical properties and physical properties. it can.

Particularly when heat resistance and curl characteristics are severely required, JP-A-6-41281, JP-A-6-43581, JP-A-6-51426 and JP-A-6-51426
-51437, 6-51442 and the like can be preferably used. A support mainly composed of a styrene polymer having a syndiotactic structure can also be preferably used. The polyester support preferably used is described in detail in Kokai Giho 94-6023 (Invention Society; March 15, 1994).

The thickness of the support is preferably 5 to 200 μm,
More preferably, it is 40 to 120 μm.

[3] Method for Detecting Thermal History In the method for detecting thermal history of the present invention, a thermoresponsive decolorizable coloring composition is applied to an object and the coloring density of the thermoresponsive decolorizable coloring composition is measured. Thus, the thermal history of the subject is detected. Specifically, the thermoresponsive decolorizable coloring composition is prepared so that the decolorization start temperature (T) becomes a specific temperature (compensation upper limit temperature, etc.) of the sample, and applied to the sample. The thermal history of the subject is detected by measuring the color density after aging and checking whether or not the color has been erased. Another method of detecting the thermal history of the present invention is to install a heat-responsive decolorizable coloring element in the vicinity of the subject, and measure the coloring concentration of the heat-responsive decolorizable coloring composition to measure the heat of the subject. It is characterized by detecting history. In this case, in order that the thermally responsive decolorizable coloring composition is decolored when the test object reaches a specific temperature, the thermal response is taken into consideration in consideration of the positional relationship and distance between the thermally responsive decolorizable coloring element and the test object. The decolorization starting temperature (T) of the decolorizable coloring composition is adjusted.

As described above, the heat-responsive color erasable coloring composition of the present invention is characterized in that the color erasing start temperature (T) is 60 to 200 ° C. Since erasing at an erasing start temperature (T) or higher is irreversible, once the temperature of the test object coated with the heat-responsive bleachable coloring composition rises above the bleaching start temperature (T), the heat-responsive bleaching starts. The coloring composition is decolored, and then the decolorization start temperature (T)
Color does not return even if returned to below. Even when the thermoresponsive decolorizable coloring element is installed in the vicinity of the subject, the thermoresponsive decolorizable coloring composition irreversibly decolors when the subject reaches a certain temperature or higher.
Therefore, the thermal history of the test object can be detected by measuring the coloring density of the thermoresponsive decolorizable coloring composition or element.

The method of measuring the coloring density is not particularly limited and is arbitrary, but when high accuracy is required, it is advantageous to measure the light absorption rate at the maximum absorption wavelength in the visible wavelength region (400 nm to 700 nm). Is.

EXAMPLES The present invention will be specifically described with reference to the following examples, but the present invention is not limited thereto.

Example 1 Preparation of Thermoresponsive Decolorizable Coloring Composition and Application to Printing <Preparation of Yellow Dye Composition 101 (Y-101)> Leuco Dye (L
1) 10 g, stearyl alcohol 4 g, color developer (SD-1) 10
g, color image stabilizer (HP-1) 10 g, and P-13 (methyl methacrylate-2-carboxyethyl acrylate copolymer (95:
5): Tg100 ° C) 20% by mass aqueous dispersion (average particle size 80 nm)
300 g was mixed with 200 ml of ethyl acetate. The obtained dispersion was mixed with 600 g of an aqueous solution in which 2.0 g of the surfactant (r) was dissolved, and emulsified and dispersed at 10,000 rpm for 20 minutes using a dissolver stirrer. After dispersion, the mixture was stirred under a nitrogen stream at 50 ° C. for 30 minutes to remove ethyl acetate, distilled water was added so that the total amount was 1,000 g, and the mixture was mixed at 2,000 rpm for 10 minutes.

<Preparation of Magenta Dye Composition 101 (M-101) and Cyan Dye Composition 101 (C-101)> Other than changing leuco dye (L1) to leuco dye (L2) and leuco dye (L3), respectively. Y-
M-101 and C-101 were prepared in the same manner as 101, respectively.

[0093]

[Chemical 21]

<Preparation and Evaluation of Ink> Dye Composition Y-10
1, M-101 and C-101 each with diethylene glycol 140
g, glycerin 50 g, SURFYNOL465 (Air Products & Ch
7 g of emicals) and 900 ml of deionized water were added to prepare yellow ink, light magenta ink and light cyan ink. These inks were filled in a cartridge of an inkjet printer PM670C (manufactured by Seiko Epson Corp.), and an image was printed on a photo print paper (manufactured by Seiko Epson Corp.) by the same machine to obtain a printed matter IJ-101. Printed material IJ-101 at 120 ° C using an electric heating oven
Heated for 5 minutes. After that, when the temperature was returned to room temperature, the image disappeared almost completely. By using the heat-responsive decolorizable coloring composition of the present invention, printed images and characters disappear by simple heating, and the paper can be reused for printing purposes.

Comparative Example 1 The amount of stearyl alcohol added was changed to 20 g, and P-
Y-10 except that 20% by weight aqueous dispersion of 13 was not added
1, similar to the method for preparing M-101 and C-101, Y-1
02, M-102 and C-102 were prepared. Y-102, M-102 and C-10
An ink was prepared in the same manner as in Example 1 using 2, and an image was printed on a photo print paper with an inkjet printer PM670C. The obtained printed matter IJ-102 was used as the printed matter IJ of Example 1.
Similar to -101, heated in an electric oven at 120 ° C for 5 minutes. The image disappeared due to heating, but when returned to room temperature, the image was almost restored in a few minutes.

[0096]

As described in detail above, when an ink is prepared from the thermoresponsive decolorizable coloring composition of the present invention and printing is performed using the ink, the image and character information are completely erased by a simple heat treatment. The printing paper can be easily recycled. Further, the thermoresponsive decolorizable coloring composition of the present invention and the thermoresponsive decolorizable colored element using the same are used for temperature detection in various industries, for example, monitoring of temperature rise in chemical reaction, overload of electric circuits and electric devices. It can be used for temperature indicators and history detection of heat generated by, and can be applied to display devices, advertising paper, teaching materials, toys, and the like.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 3/00 C09K 3/00 Y F term (reference) 2H086 BA56 BA59 BA60 4J002 BB001 BD031 BD101 BG041 CF001 CG001 CK011 CK021 CL001 EL076 EL096 EU026 EU056 EU066 EU136 EU236 GT00 4J039 AB01 AB02 AB07 AD01 AD04 AD05 AD06 AD10 AD12 AD17 AD23 AE03 AE04 AE06 AE08 BA24 BC19 BC29 BC31 BC33 BC50 BC53 BC55 BC56 BC65 BC66 BC67 BC68 BC69 BC72 BC73 BC29 BC77 CA06

Claims (12)

[Claims] 1. Coloring is performed at a temperature lower than the decoloring start temperature (T), but the color is substantially decolored at a temperature higher than the decoloring start temperature (T), and once the color is decolored, the decoloring starts again. A thermoresponsive decolorizable coloring composition that does not recolor even when returned to a temperature (T), wherein the decolorization start temperature (T) is 60 to 200 ° C., and the glass transition temperature (Tg) is 60 to A heat-responsive decolorizable coloring composition comprising a polymer at 200 ° C. 2. The heat-responsive decolorizable coloring composition according to claim 1, further comprising an electron-donating color-developing organic compound and an acidic compound. 3. The heat-responsive decolorizable coloring composition according to claim 2, wherein the acidic compound is a phenolic compound. 4. The heat-responsive decolorizable coloring composition according to claim 1, wherein the polymer has an average particle size of
A thermoresponsive decolorizable coloring composition, which is dispersed particles of 0.01 μm to 1 μm. 5. The thermoresponsive decolorizable coloring composition according to claim 1, further comprising a hydrophilic binder. 6. A thermoresponsive decolorizable coloring element comprising a support and a thermoresponsive decolorizable colored layer coated on the support, wherein the thermoresponsive decolorizable colored layer comprises: 5. A thermoresponsive decolorizable color element comprising the thermoresponsive decolorizable color composition according to any one of 5 above. 7. A method for detecting a heat history using a thermoresponsive decolorizable coloring composition, wherein the thermoresponsive decolorizable coloring composition is colored at a temperature lower than a decoloration start temperature (T). However, even if the color is substantially erased at a temperature higher than the decolorization start temperature (T), it does not recolor even if it is once decolorized and then returned to a temperature lower than the decolorization start temperature (T). The temperature (T) is 60 ~ 200 ℃, and the glass transition temperature (Tg) contains a polymer of 60 ~ 200 ℃, apply the thermoresponsive decolorizable coloring composition to the subject, the heat A method comprising detecting the thermal history of the test object by measuring the coloring concentration of the response decolorizable coloring composition. 8. The method for detecting heat history according to claim 7, wherein the thermoresponsive decolorizable color composition contains an electron-donating color-developing organic compound and an acidic compound. . 9. The method for detecting heat history according to claim 8, wherein the acidic compound is a phenolic compound. 10. The method for detecting thermal history according to claim 7, wherein the polymer has an average particle size of 0.
A method characterized in that the particles are dispersed particles of 01 μm to 1 μm. 11. The method for detecting heat history according to claim 7, wherein the heat-responsive decolorizable coloring composition contains a hydrophilic binder. 12. A method for detecting heat history using a thermoresponsive decolorizable coloring element, wherein the thermoresponsive decolorizable coloring element is a support and a thermoresponsive decolorizable coated on the support. A thermoresponsive decolorizable layer, wherein the thermoresponsive decolorizable colored layer comprises the thermoresponsive decolorizable coloring composition according to any one of claims 1 to 5, and the thermoresponsive decolorizable coloring element A method which is installed in the vicinity and detects the thermal history of the subject by measuring the coloring concentration of the thermoresponsive decolorizable coloring composition.