JPH08183253A - Reversible thermal recording material - Google Patents

Abstract

PURPOSE: To provide a practical reversible thermal recording material utilizing the reaction of a color former such as a fluorane compd. and a coupler generating a reversible hue change in the color former by heating, having good image contrast, enabling the formation and erasure of an image and lowring the visibility of an erased part due to light exposure to eliminate the adverse effect on the sharpness of an again formed image. CONSTITUTION: In a reversible thermal recording material wherein a reversible thermal recording layer containing a usually colorless or light-colored electron donating dye precursor and a reversible coupler allowing the dye precursor to form a color by heating and erasing the formed color by reheating is provided on at least the single surface of a support, a coloring layer consisting of a color dye or pigment and a binder resin is provided on the reversible thermal recording layer and a protective layer composed of an ultraviolet curable resin is provided on the coloring layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reversible thermosensitive recording material which is capable of forming an image and erasing an image by heating and is excellent in sharpness of a re-formed image.

[0002]

2. Description of the Related Art A heat-sensitive recording material generally comprises a support and a heat-sensitive recording layer containing an electron-donating, usually colorless or light-colored dye precursor and an electron-accepting developer as main components. By heating with a thermal head, a heating pen, a laser beam or the like, a dye precursor and a developer react instantaneously to obtain a recorded image. JP-B-43-4160 and JP-B-4
It is disclosed in Japanese Patent Laid-Open No. 5-14039.

In general, such a heat-sensitive recording material cannot erase the portion of the image once formed and return to the state before the image is formed. Therefore, when further information is recorded, the image is not recorded. There was no choice but to add to the formation part. Therefore, when the area of the heat-sensitive recording portion is limited, there is a problem that the recordable information is limited and it is impossible to record all the necessary information.

In recent years, reversible thermosensitive recording materials capable of repeating image formation and image erasing have been devised in order to deal with such a problem, for example, JP-A-54-119377 and JP-A-63-63. 39377, JP-A-63-4
Japanese Patent No. 1186 describes a heat-sensitive recording material composed of a resin base material and organic low-molecules dispersed in the resin base material. However, since this method reversibly changes the transparency of the heat-sensitive recording material by heat energy, the contrast between the image-formed area and the image-unformed area is insufficient.

Further, in the methods described in JP-A-50-81157 and JP-A-50-105555, since the image to be formed changes according to the ambient temperature, the image forming state and the erasing state. The holding temperatures are different, and these two states cannot be held for an arbitrary period at room temperature.

Further, in Japanese Patent Laid-Open No. 59-120492, the hysteresis characteristic of the color-developing component is utilized to keep the recording material in the hysteresis temperature range, thereby forming an image.
Although a method of maintaining the erased state is described, this method requires a heating source and a cooling source for image formation and erasure, and the temperature range in which the image formation state and the erased state can be maintained is limited to the hysteresis temperature region. However, it is still insufficient for use in the temperature environment of daily life.

On the other hand, JP-A-2-188293, JP-A-2-188294, and International Publication No. WO90 /
No. 11898 describes a reversible heat-sensitive recording material composed of a leuco dye and a color-developing and decoloring agent for coloring and decoloring the leuco dye by heating. The color-developing agent is an amphoteric compound having an acidic group for coloring the leuco dye and a basic group for decoloring the colored leuco dye, and the coloring effect by the acidic group or the decoloring effect by the basic group is controlled by controlling thermal energy. One of them is preferentially generated, and coloring and erasing are performed. However, in this method, it is impossible to completely switch the color development reaction and the color removal reaction only by controlling the thermal energy, and since both reactions occur at a certain ratio at the same time, sufficient color development density cannot be obtained, and the color removal Can not be done completely. Therefore, sufficient image contrast cannot be obtained. Also,
Since the decoloring action of the basic group also acts on the color development part at room temperature,
The phenomenon that the density of the color-developed portion decreases with time cannot be avoided.
Further, JP-A-5-124360 describes a reversible thermosensitive recording material which develops and decolorizes a leuco dye by heating, and an organic phosphoric acid compound, an α-hydroxyaliphatic carboxylic acid as an electron accepting compound, Specific phenol compounds such as alkylthiophenol, alkyloxyphenol, alkylcarbamoylphenol, and gallic acid alkylester having a fatty acid dicarboxylic acid and an aliphatic group having 12 or more carbon atoms are exemplified. But,
Even with this recording material, the two problems of low color density or incomplete decoloring cannot be solved at the same time.

The applicant has found a novel reversible developer capable of forming and erasing an image with good contrast and capable of holding a stable image over time in an environment of daily life. , Which was previously proposed in Japanese Patent Application No. 4-347032.
However, the reversible thermosensitive recording material obtained by this method is certainly capable of forming and erasing images with good contrast,
It was possible to maintain a stable image over time in the environment of daily life, but in an environment where ultraviolet rays are irradiated for a long time such as direct sunlight, the erased part of the image is colored. There was a problem. When the erased portion is colored, it is no longer possible to erase, and when the erased portion has a high coloring density, it becomes difficult to see a new image.

Further, the present applicant has provided a protective layer having a UV reflectance of less than 50% with a wavelength of 350 nm on the reversible thermosensitive recording layer, which has good color development and erasability, and is also highly lightfast. A recording material was proposed in Japanese Patent Application No. 6-680.

The reversible thermosensitive recording material thus obtained was able to maintain good light resistance, but the protective layer was peeled off or peeled off depending on the applied energy.
There are problems such as sticking, head residue, and thermal deformation of the coating layer.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to provide a reversible thermosensitive recording material which reduces the visibility of an erased portion of an image even after exposure to light and has excellent sharpness of a re-formed image.

[0012]

Means for Solving the Problems As a result of research to solve this problem, the present inventors have found that at least one surface of a support is coated with a usually colorless to light-colored electron-donating dye precursor by heating. A reversible thermosensitive recording material provided with a reversible thermosensitive recording layer containing a reversible color developing agent which develops a color of a dye precursor and reheats the color to recolor it, and a colored dye is provided on the reversible thermosensitive recording layer. Alternatively, the present invention has been achieved by providing a reversible thermosensitive recording material characterized in that a colored layer containing a coloring pigment and a binder resin and a protective layer made of an ultraviolet curable resin are sequentially laminated.

The present invention will be described in detail below.

The colored layer in the present invention must not hide the image formed in the reversible thermosensitive recording layer during image formation and keep the visibility of the erased portion low even after light exposure during image erasing. .

The colored layer in the present invention preferably has a solid coating amount of 0.5 to 5 g / m ² .

The method for forming the colored layer in the present invention is not particularly limited, and conventionally known techniques can be used. Specifically, a method of dissolving various color dyes in the binder resin solution or uniformly dispersing the color pigment in the binder resin solution and coating the solution is exemplified. When a coloring pigment is used, it is preferable that the size of the particles is small so that the image formed in the reversible thermosensitive recording property is not hidden, and the compounding amount is also limited.

As the resin used for binding, polyester resin, vinyl chloride resin, vinylidene chloride resin, vinyl chloride-vinyl acetate resin, epoxy resin, alkyd resin, acrylic resin, xylene resin, which are soluble in an organic solvent,
Butyral resin, melamine resin, polyamide resin, styrene resin, vinyl acetate-acrylic resin, etc. may be mentioned. Then, polyvinyl alcohol, styrene-maleic acid resin, ethylene-acrylic acid resin, vinyl acetate-maleic acid resin, hydroxyethyl cellulose, carboxymethyl cellulose, starch and the like, which are soluble in water, may be mentioned. Further, as the aqueous binder, styrene-butadiene type latex, styrene-acrylic type latex and the like can be used.

When a coloring dye or a coloring pigment is added to these resin solutions, the amount thereof needs to be appropriately adjusted. The specific blending amount varies depending on the hue of the coloring dye and the coloring pigment, but it suffices that the hue obviously differs when applied. Preferably, Δ of a color difference meter according to JIS Z8729
The E value may be 1.0 or more. The upper limit is determined within a range that does not hide the image.

The solid coating amount of the colored layer is generally 0.5 to
5 g / m ^2, but preferably 1 to 4 g / m ^2, the formation of the image-
In order not to reduce the heat conduction efficiency for erasing, the smaller amount is preferable. When the solid content coating amount exceeds 5 g / m ² , the heat conduction efficiency for image formation / erasure may be reduced, and the visibility of an image formed by hiding the reversible thermosensitive recording layer may be impaired. Not preferable. On the other hand, if it is less than 0.5 g / m ² , the effect of substantially reducing the visibility of the erasure mark of the image cannot be obtained.

The protective layer in the present invention preferably has a solid coating amount of 0.5 to 5 g / m ² .

The protective layer used in the present invention is exposed to a heat source such as a thermal head at the time of printing or erasing, and therefore has an important role of improving the head matching property and the like. The protective layer satisfying such conditions needs to be made of an ultraviolet curable resin. The ultraviolet curable resin has excellent adhesiveness to the colored layer and also has excellent head matching property.

Examples of the ultraviolet curable resin include compounds having an ethylenically unsaturated bond, and more specific examples include the following resins.

(1) Poly (meth) acrylate of aliphatic, alicyclic, aromatic, araliphatic polyhydric alcohol and polyalkylene glycol (2) of aliphatic, alicyclic, aromatic, araliphatic Poly (meth) acrylate of polyhydric alcohol obtained by adding alkylene oxide to polyhydric alcohol (3) Polyester poly (meth) acrylate (4) Polyurethane poly (meth) acrylate (5) Epoxy poly (meth) acrylate (6) Polyamide Poly (meth) acrylate (7) Poly (meth) acryloyloxyalkyl phosphate ester (8) Vinyl- or diene-based compound having a (meth) acryloyloxy group at the side chain or terminal (9) Monofunctional (meth) acrylate , Vinylpyrrolidone, (meth) acryloyl compound (10) Ethylenic fatigue Cyano compound having a bond (11) Mono- or polycarboxylic acid having an ethylenically unsaturated bond, and their alkali metal salts, ammonium salts, amine salts, etc. (12) Ethylenically unsaturated (meth) acrylamide or alkyl-substituted (meth) ) Acrylamide and its multimers (13) Vinyllactam and polyvinyllactam compounds (14) Polyether having ethylenically unsaturated bond and its ester (15) Alcohol ester having ethylenically unsaturated bond (16) Ethylenically unsaturated Polyalcohol having bond and ester thereof (17) Aromatic compound having one or more ethylenically unsaturated bond such as styrene and divinylbenzene (18) Polyorganosiloxane having (meth) acryloyloxy group in side chain or terminal Service (19) Silicone compound having ethylenically unsaturated bond (20) Multimer or oligoester (meth) acrylate-modified product of the compound described in (1) to (19) above

These resins can be used alone or as a mixture with other resins. Further, it can be applied without a solvent, or can be applied, dried and cured in an emulsion state before use.

When the resin is cured by the ultraviolet curing method in the present invention, a photoreaction initiator is mixed and used. Examples of the photoinitiator include acetophenones such as di- and trichloroacetophenone, benzophenone, Michler's ketone, benzyl, benzoin, benzoin alkyl ether, benzyl dimethyl ketal, tetramethyl thiuram monosulfide, thioxanthones, azo compounds and various silver salts. The amount of the photoreaction initiator used is usually in the range of 0.1 to 10% with respect to the ultraviolet curable resin. Storage stabilizers such as hydroquinone may also be used as the photoinitiator.

As the ultraviolet irradiation device, there are, for example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, and the like, and there is also an ozoneless type that generates less ozone. Generally, a plurality of lamps having an output of 30 w / cm or more are used in parallel.

Further, a pigment may be contained in order to reduce the occurrence of sticking after the UV curable resin is cured. The pigment here is an organic pigment,
Any of inorganic pigments may be used. For example, heavy calcium carbonate, light calcium carbonate, barium sulfate, kaolin, calcined kaolin, talc, aluminum hydroxide, aluminum silicate, magnesium oxide, magnesium carbonate, silica gel, colloidal silica, alumina sol, magnesium sulfate, zinc oxide, activated clay, Examples thereof include, but are not limited to, fine powder silicic acid, titanium oxide, calcium silicate, polyolefin resin, polystyrene resin, urea-formaldehyde resin, styrene-acrylic resin, acrylic resin, and silicone resin. These pigments can be used alone or in combination of two or more kinds.

If desired, a lubricant may be added to the protective layer. Lubricants are mainly waxes such as stearic acid amide, oleic acid amide, lauric acid amide, ethylenebisstearic acid amide, methylenebisstearic acid amide, methylolstearic acid amide,
Examples thereof include paraffin wax, polyethylene wax, higher alcohol, higher fatty acid, higher fatty acid ester, and silicone compound, but are not limited thereto.

The coating amount of the protective layer is desired to be thinner for the purpose of avoiding heat cutoff, and is preferably 0.5 to 5 g / m ² .
When it is less than this range, the function as a good protective layer does not appear, and when it is more than this range, the thermal sensitivity is deteriorated.

The method of applying the protective layer of the present invention includes:
Gravure roll and transfer roll coater, bar coater, roll coater, air knife coater, U
Comma coater, AKKU coater, smoothing coater, micro gravure coater, air knife coater, reverse roll coater, 4 or 5 roll coater, blade coater, dip coater, bar coater, rod coater, kiss coater, gate roll coater, squeeze coater, drop Any coater such as a curtain coater, a slide coater, or a die coater may be used.

The usually colorless or light-colored electron-donating dye precursor used in the present invention is represented by those generally used for pressure-sensitive recording paper, heat-sensitive recording paper, etc., but is not particularly limited. Specific examples include the followings, but the present invention is not limited thereto.

(1) Triarylmethane compound 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3-
(1,2-dimethylindol-3-yl) phthalide,
3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindole-
3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3-)
Yl) -6-Dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5 -Dimethylaminophthalide, 3-p
-Dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide and the like,

(2) Diphenylmethane compound 4,4'-bis (dimethylaminophenyl) benzhydryl benzyl ether, N-chlorophenyl leuco auramine, N-2,4,5-trichlorophenyl leuco auramine, etc.

(3) Xanthene compound Rhodamine B anilinolactam, rhodamine B-p-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-octylaminofluorane, 3- Diethylamino-7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-diethylamino-6-chloro-7-methylfluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3 -Diethylamino-7
-(2-chloroanilino) fluorane,

3-Diethylamino-6-methyl-7-anilinofluorane, 3- (N-ethyl) tolylamino-
6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3- (N-ethyl) tolylamino-6-methyl-7-phenethylfluorane, 3-diethylamino-7 -(4-Nitroanilino) fluorane, 3-dibutylamino-6-methyl-7
-Anilinofluorane, 3- (N-methyl) propylamino-6-methyl-7-anilinofluorane, 3- (N
-Ethyl) isoamylamino-6-methyl-7-anilinofluorane, 3- (N-methyl) cyclohexylamino-6-methyl-7-anilinofluorane, 3- (N-
Ethyl) tetrahydrofurylamino-6-methyl-7-
Anilino Fluoran, etc.

(4) Thiazine-based compounds benzoyl leuco methylene blue, p-nitrobenzoyl leuco methylene blue, etc.

(5) Spiro compound 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3 -Methoxybenzo) spiropyran, 3-propylspirobenzopyran and the like.

The usually colorless to light-colored dye precursors may be used either individually or in combination of two or more.

The reversible developer used in the present invention is not particularly limited as long as it is a compound capable of causing a reversible color change in the dye precursor upon heating, but from the viewpoint of the contrast of the image, the durability of repetition, etc., the present applicant According to JP-A-6
An electron-accepting compound represented by the following chemical formula 1 (general formula 1) is preferably used, including a reversible color developing agent composed of a phenolic compound proposed in JP-A-210954.

[0040]

Embedded image In the formula, n represents 1, 2 or 3. m represents 0, 1 or 2. Q represents an aliphatic hydrocarbon group, an alkoxy group or a halogen atom. The ring represented by A is an aromatic ring. X is a divalent group bonded to the aromatic ring represented by A through a nitrogen atom, a divalent group containing two or more hetero atoms, a nitrogen atom, and A
Represents a divalent group which is bonded to the aromatic ring by a hydrocarbon group having 1 or more carbon atoms, or a divalent group containing an unsaturated bond or an aromatic ring. R represents an aliphatic hydrocarbon group. X
The total number of atoms contained in R and R is 8 or more, excluding hydrogen atoms and atoms constituting the aromatic ring.

Specific examples of the substituent represented by Q include methyl group, ethyl group, propyl group, isopropyl group and n-
Butyl group, t-butyl group, t-pentyl group, 2-ethylhexyl group, cyclohexyl group, allyl group and other aliphatic hydrocarbon groups, methoxy group, ethoxy group, n-propyloxy group, i-propyloxy group, n -Butyloxy group, n
-Alkoxy groups such as an octyloxy group and halogen atoms such as fluorine, chlorine, bromine and iodine.

Examples of the divalent group in which X is bonded to the aromatic ring represented by A through the nitrogen atom include --NHCO-- and --NHCO--.
NH-, -NHCONH-, -NHCONHNH-,-
N = CH -, - N = N -, - NHSO 2 -, -NHCO
_{(P-C 6 H 4)} NHCO -, - NHCO (p-C 6 H 4)
NHCONH -, - NHCO (p- C 6 H 4) NHCOC
ONH -, - NHCO (p- C 6 H 4) CONH -, - N
_{HCO (p-C 6 H 4} ) CONHNHCO -, - NHCO
_{(P-C 6 H 4)} OCONH -, - NHCO (p-C
₆ H ₄ ) NHCOO-, -NHCOCH ₂ (m-C ₆ H ₄ ).
_{NHCO -, - NHCOCH 2 (p} -C 6 H 4) NHCO
_{-, - NHCOCH 2 (p-} C 6 H 4) NHCONH-,
_{-NHCOCH 2 (p-C 6 H} 4) NHCOCONH-,
_{-NHCOCH 2 (p-C 6 H} 4) CONH -, - NHC
_{OCH 2 (p-C 6 H} 4) CONHNHCO -, - NHC
_{OCH 2 (p-C 6 H} 4) CONHNHCONH -, - N
_{HCOCH 2 (p-C 6 H} 4) CONHNHCOO-, -
_{NHCOCH 2 (p-C 6 H} 4) OCONH -, - NHC
_{OCH 2 (p-C 6 H} 4) NHCOO-, -NHCOCH
_{2 CH 2 (p-C 6} H 4) NHCO -, - NHCOCH 2 C
_{H 2 (p-C 6 H} 4) NHCONH -, - NHCOCH 2 C
_{H 2 (m-C 6 H} 4) NHCOO -, - NHCOCH 2 CH
_{2 (p-C 6 H 4} ) NHCOCONH -, - NHCOCH 2
_{CH 2 (p-C 6 H} 4) CONH -, - NHCOCH 2 CH
_{2 (p-C 6 H 4} ) CONHNHCO -, - NHCOCH 2
_{CH 2 (p-C 6 H} 4) CONHNHCONH- the like.

When a hydrogen atom is bonded to the nitrogen atom,
The hydrogen atom may be substituted with an aliphatic hydrocarbon group such as a methyl group or a cyclohexyl group. Of these, the urea bond is more preferable in terms of decoloring property and image density. Interestingly, when X is -CONH-, -COO-, or -S-, either the decoloring property or the image density becomes unsatisfactory.

Examples of the divalent group where X is two or more heteroatoms include --SO ₂ NH--, --SS--, --CON.
HNH -, - CONHNHCO -, - CONHCH 2 C
O -, - CONHNHCOO -, - CONHCH 2 CO
_{O-, -CONHNHCONH -, - CONHCH 2} C
ONH-, -CONHNHCONHNH-, -CON
_{HCH 2 CONHNH -, - CH 2} NHCONH -, - C
_{H 2 CH 2 NHCONH -, -} CH 2 CH 2 CH 2 NHCO
_{NH -, - CH 2 CH 2} CH 2 NHCONH -, - SCH 2
_{CONH -, - SCH 2 CH 2} CONH -, - S (C
_{H 2) 5 CONH-, -S (} CH 2) 10 CONH -, - S
_{(P-C 6 H 4)} CONH -, - SCH 2 NHCO -, -
_{SCH 2 CH 2 NHCO -, -} S (CH 2) 6 NHCO-,
_{-S (p-C 6 H 4} ) NHCO -, - SCH 2 NHCON
_{H -, - SCH 2 CH 2} NHCONH-, -S (CH 2)
_{6 NHCONH -, - S (p} -C 6 H 4) NHCONH
_{-, - S (CH 2)} 10 NHCONH -, - SCH 2 CH 2
_{NHCOO -, - S (CH 2} ) 6 NHCOO -, - S (p
_{-C 6 H 4) NHCOO -,} - S (CH 2) 6 OCONH
-, - S (p-C 6 H 4) OCONH -, - S (CH 2)
₁₁ OCONH-, -SCH ₂ CH ₂ CONH-, -S
_{(CH 2) 5 CONH -,} - SCH 2 CH 2 NHCO (p-
_{C 6 H 4) -, -} SCH 2 CONHNHCO -, - SCH 2
_{CH 2 CONHNHCO -, - S (} CH 2) 6 CONHN
_{HCO-, -S (CH 2) 6} CONHNHCO (p-C 6
_{H 4) -, - S (} CH 2) 10 CONHNHCO-, -S
_{(P-C 6 H 4)} CONHNHCO -, - SCH 2 (p-
_{C 6 H 4) CONHNHCO-, -SCH} 2 CH 2 NHC
_{OCONH -, - SCH 2 CH 2} CH 2 NHCOCONH
_{-, - S (CH 2)} 11 NHCOCONH -, - S (p-
_{C 6 H 4) NHCOCONH-, -SCH} 2 CONHCO
_{NH -, - SCH 2 CH 2} CONHCONH -, - S (p
_{-C 6 H 4) CONHCONH -,} - SCH 2 CH 2 NHC
ONHCO -, - S (p- C 6 H 4) NHCONHCO
_{-, - SCH 2 CH 2 CONHNHCONH-} , -S
_{(CH 2) 10 CONHNHCONH -,} - SCH 2 CH 2
NHNHCONH -, - S (p- C 6 H 4) NHNHCO
_{NH -, - SCH 2 CH 2} NHCONHNH -, - S (p
_{-C 6 H 4) NHCONHNH -,} - SCH 2 CONHC
ONHNH-, -SCH ₂ CH ₂ CONHCONHNH
_{-, - S (CH 2)} 10 CONHCONHNH-, -S
_{(P-C 6 H 4)} CONHNHCONH-, -S (p-
_{C 6 H 4) CONHCONHNH -,} - SCH 2 CONH
_{CONHNHCO -, - SCH 2 CH 2} CONHCONH
_{NHCO -, - S (CH 2} ) 10 CONHCONHNHC
_{O-, -S (p-C 6} H 4) CONHNHCONHCO
_{-, -S (p-C 6} H 4) CONHCONHNHCO
_{-, - SCH 2 CONH (CH} 2) NHCO -, - SCH
_{2 CH 2 CONH (CH 2)} NHCO -, - S (p-C 6 H
_{4) CONH (CH 2) NHCO} -, - S (CH 2) 10 C
_{ONH (CH 2) NHCO -,} - SCH 2 CON (C
_{H 2) NHCONH -, - SCH} 2 CH 2 CON (CH 2)
_{NHCONH -, - S (CH 2} ) 10 CONHCONH
_{(CH 2) NHCO -, -} S (p-C 6 H 4) CONH
_{(CH 2) NHCO -, -} SCH 2 CH 2 NHCONH
_{(CH 2) NHCO -, -} SCH 2 CH 2 NHCOCH 2 C
ONH -, - S (p- C 6 H 4) NHCONH (CH 2)
_{NHCO-, -S (p-C 6} H 4) NHCOCH 2 CON
H- and the like can be mentioned.

Specific examples of the hetero atom include an oxygen atom,
Nitrogen atom, sulfur atom, phosphorus atom, boron atom, silicon atom,
Examples thereof include selenium atom, fluorine atom, chlorine atom, bromine atom, iodine atom and tin atom.

2 wherein X contains an unsaturated bond or an aromatic ring
Examples of the valent group include -CH = CH-, -CH = N-,
—SO ₂ —, a phenylene group, a group containing a carbon-carbon triple bond, a group in which they are combined, and further, on one or both sides thereof, —NHCO mentioned above as another example of X.
-, -NH-, -NHCONH-, -NHCSNH-,
-N = CH -, - N = N -, - NHSO 2 -, - SO 2 N
Examples thereof include groups combining one or two or more linking groups such as H and -SS-. In this case, in addition to the linking group, -CONH-, -O-, -S-, -COO-, -O.
CO -, - OCOO, -CO - , - SO 2 - 2 a divalent group, such as may also be mentioned.

Examples of the divalent group in which X contains a nitrogen atom and is bonded to the aromatic ring represented by A by a hydrocarbon group having 1 or more carbon atoms are --CH ₂ CONH--, --CH ₂ CH ₂ CO
_{NH -, - CH 2 NHCO -} , - CH 2 CH 2 NHCO
_{-, - CH 2 CH 2 CH} 2 NHCO -, - CH 2 CH 2 NH
_{COO -, - (CH 2)} 6 NHCOO -, - (p-C
_{6 H 4) NHCOO -, -} CH 2 CH 2 OCONH-, -
_{(CH 2) 11 OCONH -,} - (p-C 6 H 4) OCON
_{H -, - CH 2 CH 2} CONHCO -, - (CH 2) 5 CO
_{NHCO -, - CH 2 CH 2} CONHCO (p-C 6 H 4)
_{-, -CH 2 CONHNHCO -, -} CH 2 CH 2 CON
_{HNHCO -, - (CH 2)} 5 CONHNHCO -, -
_{(CH 2) 5 CONHNHCO (p} -C 6 H 4) -, -
_{(CH 2) 10 CONHNHCO -,} - (p-C 6 H 4) C
_{ONHNHCO-, -CH 2 (p-C} 6 H 4) CONHN
_{HCO -, - CH 2 CH 2} NHCOCONH-, -CH 2
_{CH 2 CH 2 NHCOCONH -, -} (CH 2) 10 NHC
_{OCONH-, - (p-C 6} H 4) NHCOCONH
_{-, - CH 2 CONHCONH-, -CH} 2 CH 2 CON
HCONH -, - (p-C 6 H 4) CONHCONH-,
_{-CH 2 CH 2 NHCONHCO -, -} (p-C 6 H 4) N
_{HCONHCO -, - CH 2 CH 2} NHCONHNH-,
_{- (p-C 6 H 4} ) NHCONHNH -, - CH 2 CH 2 N
HNHCONH -, - (p-C 6 H 4) NHNHCONH
_{-, -CH 2 CONHNHCONH -, -} CH 2 CH 2 C
_{ONHNHCONH-, - (CH 2) 10} CONHNHC
ONH -, - (p-C 6 H 4) NHNHCO-, -CH 2
_{CONHCH 2 NHCO -, - CH 2} CH 2 CONHCH 2
_{NHCO -, - (CH 2)} 10 CONHCH 2 NHCO-,
_{- (p-C 6 H 4} ) CONHCH 2 NHCO-, -CH 2
CONHCH ₂ NHCONH-, -CH ₂ CH ₂ CONH
_{CH 2 NHCONH-, - (CH 2} ) 10 CONHCH 2 N
HCONH -, - (p-C 6 H 4) CONHCH 2 NHC
_{ONH -, - CH 2 CH 2} NHCONHCH 2 NHCO
_{-, - (p-C 6} H 4) NHCONHCH 2 NHCO-,
_{-CH 2 CH 2 NHCOCH 2 CONH -} , - (p-C 6 H
₄ ) NHCOCH ₂ CONH- and the like.

As the aliphatic hydrocarbon group represented by R,
Hexyl group, octyl group, nonyl group, cyclohexyl group, decyl group, undecyl group, dodecyl group, cyclododecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, 16-methylheptadecyl group, octadecyl group, 9-octadecenyl group, nonadecyl group, aicosyl group, henicosyl group,
Examples thereof include docosyl group, tricosyl group, tetracosyl group, 2-norbornyl group, 7,7-dimethylnorbornyl group, 1-adamantyl group, cholesteryl group and 5-phenylpentyl group. These may be branched, may be polycyclic, and may contain an unsaturated bond. However, it is necessary for the decoloring property that the total number of the atoms included in X and R excluding the hydrogen atom and the atoms constituting the aromatic ring is 8 or more, particularly 14 or more.

Next, specific examples of the reversible color developing agent preferably used in the present invention will be given, but the present invention is not limited thereto.

4'-hydroxyheptane anilide, 4 '
-Hydroxy-3-methyloctaneanilide, 4'-hydroxynonadecaneanilide, 3'-hydroxynonadecaneanilide, 4'-hydroxy-10-octadeceneanilide, 15-cyclohexyl-4'-hydroxypentadecaneanilide, 4'- Hydroxy-5-tetradeceneanilide, 3'-cyclohexyl-4'-hydroxyheptadecaneanilide, 3'-allyl-4'-hydroxypentadecaneanilide, 3'-chloro-4'-hydroxyoctadecaneanilide, 3'-hydroxydodecane Anilide, 2 ', 4'-dihydroxyheptadecane anilide,

4'-hydroxy-4-hexylbenzanilide, 4'-hydroxy-4-octadecylbenzanilide, 4'-hydroxy-4-pentadecylaminocarbonylbenzanilide, 4'-hydroxy-4-hexylcarbonylaminobenz Anilide, 4'-hydroxy-4- (heptylthio) benzanilide, 4'-hydroxy-4-octadecyloxybenzanilide, 4 '
-Hydroxy-4-dodecylsulfonylbenzanilide, 4'-hydroxy-4-nonylsulfonyloxybenzanilide, 4'-hydroxy-4-dodecyloxysulfonylbenzanilide, 4'-hydroxy-4-pentadecylaminosulfonylbenzanilide, 4'-hydroxy-4- (N-heptadecylideneamino) benzanilide,

4'-hydroxy-3,4-dioctyloxybenzanilide, 4'-hydroxy-3-octyl-4- (octylthio) benzanilide, 4'-hydroxy-3- (heptadecylthio) -5-pentadecyloxybenz Anilide, 4'-hydroxy-3-heptadecylcarbonylamino-5-dodecylbenzanilide,
4'-hydroxy-3-octadecylaminocarbonyl-5-tetradecylaminocarbonylbenzanilide,
4'-hydroxy-3-octadecylsulfonylamino-5-octadecyloxybenzanilide, 4'-hydroxy-3-heptadecyloxysulfonyl-5-tetradecyloxysulfonylbenzanilide, 4'-hydroxy-3,5-bis ( N-docosylideneamino) benzanilide,

4'-hydroxy-4-octadecylcarbonylaminobenzanilide, 4'-hydroxy-3-
Octadecylcarbonylamino-5-octadecyloxybenzanilide, 3'-allyl-4'-hydroxy-
4-pentadecylbenzanilide, 4'-hydroxy-
3'-methyl-4-nonyloxybenzanilide, 4 '
-Hydroxy-3'-propyl-4-nonadecylcarbonyloxybenzanilide, 3'-butyl-4'-hydroxy-4-octadecyloxycarbonylbenzanilide, 3'-hydroxy-4-pentadecylcarbonyloxybenzanilide, 3 '-Hydroxy-4-nonadecylsulfonylbenzanilide, 3', 4 ', 5'-trihydroxy-4-tetracosylaminosulfonylbenzanilide, 3', 5'-dihydroxy-4-pentacosylaminocarbonylbenz Anilide, 3'-hydroxy-4- (N-dodecylideneamino) benzanilide,
N- [4- (3-hydroxyphenylaminocarbonyl) benzylidene] pentadecylamine,

N-cyclohexyl-4-hydroxybenzhydrazide, N-cyclohexylmethyl-4-hydroxybenzhydrazide, N-cyclohexyl-4-hydroxybenzamide, N-cyclohexylmethyl-4-
Hydroxybenzamide, N-methyl-N-octadecyl-4-hydroxybenzamide, N- (3-methylhexyl) -4-hydroxybenzamide, N-octadecyl-4-hydroxybenzhydrazide, N- (8-octadecenyl) -4- Hydroxybenzamide,

4-hydroxy-4'-dodecylbenzanilide, N-methyl-4-hydroxy-4'-octadecylbenzanilide, 4-hydroxy-4'-octadecyloxybenzanilide, 4-hydroxy-4'-
(Octadecylthio) benzanilide, 4-hydroxy-4'-hexadecylcarbonylbenzanilide, 4-
Hydroxy-4′-heptadecyloxycarbonyloxybenzanilide, 4-hydroxy-4′-dodecyloxycarbonylbenzanilide, 4-hydroxy-4 ′
-Heptadecyl carbonyloxybenzanilide, 4-
Hydroxy-4′-cyclohexylaminobenzanilide, 4-hydroxy-4′-octadecylaminobenzanilide,

4-Hydroxy-4'-heptadecylcarbonylaminobenzanilide, 4-hydroxy-4'-
Octadecylaminocarbonylbenzanilide, 4-hydroxy-4'-dodecylsulfonylbenzanilide, 4-hydroxy-4'-octadecyloxysulfonylbenzanilide, 4-hydroxy-4'-dodecylsulfonyloxybenzanilide, N-4-hydroxybenzoyl -N'-octadecylidene-1,4-phenylenediamine, N-4- (4-hydroxyphenylcarbonylamino) benzylidenedecylamine, 4-
Hydroxy-4′-tetradecyloxycarbonylaminobenzanilide, 4-hydroxy-4′-octadecylureylenebenzanilide,

3-Hydroxy-4'-dodecyloxybenzanilide, N-methyl-4-hydroxy-3'-octadecyloxybenzanilide, 3-hydroxy-
4'-tetradecylbenzanilide, N-methyl-3-
Hydroxy-4'-octadecylbenzanilide, N-
Dodecyl-4-hydroxy-3-methylbenzamide,
3-Methoxy-4-hydroxy-4'-octadecyloxybenzanilide, 3-chloro-4-hydroxy-
4'-octadecylbenzanilide, N-octadecyl-4-hydroxy-2,5-dimethylbenzamide, 4
-Hydroxy-4'-octadecyloxy-3'-chlorobenzanilide, 4-hydroxy-3 ', 4'-didecyloxybenzanilide, 4-hydroxy-3'-octadecylamino-4'-octadecyloxybenzanilide, 4-hydroxy-2'-chloro-3 ', 5'-
Didecyloxybenzanilide, 4-hydroxy-
3 ', 4'-dioctadecyloxybenzanilide, 4
-Hydroxy-4'-octyl-3'-methylbenzanilide, 3-hydroxy-4-methyl-4'-tetradecylbenzanilide, N-methyl-4-hydroxy-
3'-octadecylbenzanilide,

4- (N-octadecylsulfonylamino) phenol, 4- (N-methyl-N-octadecylsulfonylamino) phenol, 4- (N-3-methylhexylsulfonylamino) phenol, 4'-hydroxy-4- Cyclohexylbenzene sulfone anilide,
4'-hydroxy-4-octadecyloxybenzenesulfonanilide, 4'-hydroxy-4- (dodecylthio) benzenesulfonanilide, 4'-hydroxy-4
-Hexylcarbonylbenzenesulfonanilide, 4 '
-Hydroxy-4- (8-heptadecenyl) carbonylbenzenesulfonanilide, 4'-hydroxy-4-octyloxycarbonyloxybenzenesulfonanilide, 4'-hydroxy-4-dodecylcarbonyloxybenzenesulfonanilide, 4'-hydroxy-4 -Octadecylaminobenzenesulfonanilide,

4'-hydroxy-4-heptadecylcarbonylaminobenzenesulfonanilide, 4'-hydroxy-4-dodecylaminocarbonylbenzenesulfonanilide, 4'-hydroxy-4-dodecylsulfonylbenzenesulfonanilide, 4'-hydroxy- 4-Octadecyloxysulfonylbenzenesulfonanilide, 4'-hydroxy-4-dodecylsulfonyloxybenzenesulfonanilide, N-dodecylidene-4-
(4-hydroxyphenyl) aminosulfonylaniline, N-4- (4-hydroxyphenylaminosulfonyl) benzylidene octadecylamine, 4'-hydroxy-4-octyloxycarbonylaminobenzenesulfonanilide, 4'-hydroxy-4-octadecyloxy Carbonylaminobenzenesulfonanilide, 4 '
-Hydroxy-4-octadecylureylene benzenesulfonanilide,

N-methyl-4'-hydroxy-3-octadecyloxybenzenesulfonanilide, 3'-hydroxy-4-dodecylbenzenesulfonanilide, 3-
Methyl-4- (N-dodecylsulfonamino) phenol, 3'-methoxy-4'-hydroxy-4-octadecyloxybenzenesulfonanilide, 3'-chloro-
4'-hydroxy-4-octadecylbenzenesulfonanilide, 4'-hydroxy-2,5-dimethyl-4-
Octadecylbenzenesulfonanilide, 3-methyl-
4- (N-octadecylsulfonamino) phenol,
4'-hydroxy-3,4-dioctadecyloxybenzenesulfonanilide,

1- (4-hydroxyphenyldithio) octadecane, 1- (4-hydroxyphenyldithio)-
9-octadecene, 1- (2-fluoro-4-hydroxyphenyldithio) octadecane, 1- (2-ethoxy-4-hydroxyphenyldithio) octadecane, 1-
(3-chloro-4-hydroxyphenyldithio) octadecane,

4'-hydroxy-4-tetradecyldiphenyl sulfide, 4'-hydroxy-4-octadecyldiphenyl sulfide, 4'-hydroxy-4-octadecylcarbonylaminodiphenyl sulfide, 4 '
-Hydroxy-4-octadecyloxydiphenyl sulfide, 4'-hydroxy-4-octadecyloxysulfonyl diphenyl sulfide, 4'-hydroxy-4
-Octadecylsulfonylaminodiphenyl sulfide,

4'-hydroxy-3,4-didecyloxydiphenyl sulfide, 4'-hydroxy-3,4-
Dioctadecyloxydiphenyl sulfide, 4- (1
5-cyclohexylpentadecyl) -4'-hydroxydiphenyl sulfide, 4'-hydroxy-4- (5-
Tetradecenyl) diphenyl sulfide,

3'-chloro-4'-hydroxy-4-octadecyldiphenyl sulfide, 3'-hydroxy-
4-dodecyl diphenyl sulfide, 3'-hydroxy-4-octadecyl diphenyl sulfide, 3'-hydroxy-4-dodecyloxycarbonyl diphenyl sulfide,

N- (4-hydroxyphenyl) -N'-
Hexyl urea, N- (4-hydroxyphenyl) -N '
-Dodecyl urea, N- (4-hydroxyphenyl)-
N'-hexadecylurea, N- (4-hydroxyphenyl) -N'-octadecylurea, N- (4-hydroxyphenyl) -N'-eicosylurea, N- (4-hydroxyphenyl) -N'-cyclododecyl Urea, N- (4
-Hydroxyphenyl) -N'-docosylurea, N-
(4-hydroxyphenyl) -N'-cholesteryl urea, N- (4-hydroxyphenyl) -N '-(2-heptyloctyl) urea, N- (4-hydroxyphenyl) -N'-(9-octadecenyl) urea,

N- (3-allyl-4-hydroxyphenyl) -N'-octadecylurea, N- (2-hydroxyphenyl) -N'-octylurea, N- (3-hydroxyphenyl) -N'-octadecyl Urea, N- (3,4
-Dihydroxyphenyl) -N'-octadecylurea,
N- (3,4,5-trihydroxyphenyl) -N'-
Tricosyl urea, N- (4-hydroxyphenyl)-
N '-(4-tetradecylphenyl) urea, N- (4-
Hydroxyphenyl) -N'-hexadecylthiourea,
N- (4-hydroxyphenyl) -N'-octadecylthiourea,

4-undecanoylamino-1- (4-hydroxyphenylaminocarbonyl) benzene, 4-octadecanoylamino-1- (4-hydroxyphenylaminocarbonyl) benzene, 4- (octadecylaminocarbonyl) amino- 1- (4-hydroxyphenylaminocarbonyl) benzene, 4-octadecylamino-1- (4-hydroxyphenylamino) carbonylmethylbenzene, N-octadecyl-N'-p- (4-hydroxyphenylcarbamoyl) phenyloxamide,
4- (octadecylaminocarbonyl) amino-1-
(4-Hydroxyphenylcarbamoyl) methylbenzene, 4- (octadecylamino) carbonyl-1- (4
-Hydroxyphenylcarbamoyl) methylbenzene,
N-octadecanoyl-N'-p- (p-hydroxyphenylcarbamoylmethyl) benzoylhydrazine, N
-Dodecanoyl-N'-p- [2- (p-hydroxyphenylcarbamoyl) ethyl] benzoylhydrazine,

N- (4-hydroxyphenylmethyl)-
N'-n-tetradecyl urea, N- (4-hydroxyphenylmethyl) -N'-n-octadecyl urea, N-
[2- (4-hydroxyphenyl) ethyl] -N'-n
-Tetradecyl urea, N- [2- (4-hydroxyphenyl) ethyl] -N'-n-octadecyl urea, N-
[3- (4-hydroxyphenyl) propyl] -N'-
n-dodecyl urea, N- [3- (4-hydroxyphenyl) propyl] -N'-n-octadecyl urea, N-
[6- (4-hydroxyphenyl) hexyl] -N'-
n-dodecylurea, N- [2- (3-hydroxyphenyl) ethyl] -N'-n-octadecylurea, N- [2
-(3,4-Dihydroxyphenyl) ethyl] -N'-
n-octadecyl urea,

Nn-octadecyl- (4-hydroxyphenyl) acetamide, Nn-dodecyl-3- (4
-Hydroxyphenyl) propanamide, Nn-octadecyl-3- (4-hydroxyphenyl) propanamide, N- (4-hydroxyphenylmethyl) octadecane amide, N- [2- (4-hydroxyphenyl) ethyl] octadecane Amide, N- [3- (4-hydroxyphenyl) propyl] octadecanamide, N- [3
-(3-Hydroxyphenyl) propyl] octadecanamide, N- [3- (3,4-dihydroxyphenyl)
Propyl] octadecanamide,

N- (4-hydroxybenzoyl) -N '
-N-octanoylhydrazine, N- (4-hydroxybenzoyl) -N'-n-tetradecanoylhydrazine, N- (4-hydroxybenzoyl) -N'-n-octadecanoylhydrazine, N- (2, 4-dihydroxybenzoyl) -N'-n-octanoylhydrazine,
N- (2,4-dihydroxybenzoyl) -N'-n-
Octadecanoylhydrazine, N- (4-hydroxybenzoyl) -N'-n-tetradecylaminocarbonylhydrazine, N- (4-hydroxybenzoyl) -N '
-N-octadecylaminocarbonylhydrazine, N-
(2,4-dihydroxybenzoyl) -N'-n-tetradecylaminocarbonylhydrazine, N- (2,4-
Dihydroxybenzoyl) -N'-n-octadecylaminocarbonylhydrazine, N- (4-hydroxybenzoyl) -N'-n-octyloxycarbonylhydrazine, N- (4-hydroxybenzoyl) -N'-n-
Dodecyloxycarbonyl hydrazine, N- (2,4-
Dihydroxybenzoyl) -N'-n-tetradecyloxycarbonylhydrazine, N- (2,4-dihydroxybenzoyl) -N'-n-octadecyloxycarbonylhydrazine, N- (4-hydroxybenzoyl)-
N'-n-tetradecylhydrazinocarbonylhydrazine, N- (4-hydroxybenzoyl) -N'-n-octadecylhydrazinocarbonylhydrazine, N-
(2,4-dihydroxybenzoyl) -N'-n-tetradecylhydrazinocarbonylhydrazine, N- (2,2
4-dihydroxybenzoyl) -N'-n-octadecylhydrazinocarbonylhydrazine,

N- (4-hydroxybenzoyl) -N '
-N-octanoylmethylenediamine, N- (4-hydroxybenzoyl) -N'-n-tetradecanoylmethylenediamine, N- (4-hydroxybenzoyl)-
N'-n-octadecanoylmethylenediamine, N-
(2,4-Dihydroxybenzoyl) -N'-n-tetradecanoylmethylenediamine, N- (2,4-dihydroxybenzoyl) -N'-n-octadecanoylmethylenediamine, N- (4-hydroxybenzoyl) −
N'-n-octylaminocarbonylmethylenediamine, N- (4-hydroxybenzoyl) -N'-n-dodecylaminocarbonylmethylenediamine, N- (4-
Hydroxybenzoyl) -N'-n-tetradecylaminocarbonylmethylenediamine, N- (4-hydroxybenzoyl) -N'-n-octadecylaminocarbonylmethylenediamine, N- (2,4-dihydroxybenzoyl) -N'- n-octadecylaminocarbonylmethylenediamine, N- (4-hydroxybenzoyl)-
N'-n-tetradecyloxycarbonylmethylenediamine, N- (4-hydroxybenzoyl) -N'-n-
Octadecyloxycarbonyl methylenediamine, N-
(2,4-dihydroxybenzoyl) -N'-n-tetradecyloxycarbonylmethylenediamine, N-
(2,4-dihydroxybenzoyl) -N'-n-octadecyloxycarbonylmethylenediamine, N- (4
-Hydroxybenzoyl) -N'-n-octylhydrazinocarbonylmethylenediamine, N- (4-hydroxybenzoyl) -N'-n-dodecylhydrazinocarbonylmethylenediamine, N- (2,4-dihydroxybenzoyl) -N '-N-tetradecylhydrazinocarbonylmethylenediamine, N- (2,4-dihydroxybenzoyl) -N'-n-octadecylhydrazinocarbonylmethylenediamine,

Nn-octadecyl-2- (p-hydroxyphenylthio) acetamide, Nn-octadecyl-3- (p-hydroxyphenylthio) propanamide, Nn-decyl-11- (p-hydroxy Phenylthio) undecane amide, N- (pn-octylphenyl) -6- (p-hydroxyphenylthio) hexanamide, Nn-octadecyl-p- (p-hydroxyphenylthio) benzamide, N- [2 -(P-Hydroxyphenylthio) ethyl] -n-octadecanamide, N- [p- (p-hydroxyphenylthio) phenyl] -n-octadecanamide, N- (p-hydroxyphenylthio) methyl-N'- n-octadecyl urea,
N- [2- (p-hydroxyphenylthio) ethyl]-
N'-n-tetradecyl urea, N- [2- (p-hydroxyphenylthio) ethyl] -N'-n-octadecyl urea, N- [2- (3,4-dihydroxyphenylthio) ethyl] -N ' -N-octadecyl urea, N- [p
-(P-hydroxyphenylthio) phenyl] -N'-
n-octadecyl urea, N- [10- (p-hydroxyphenylthio) decyl] -N'-n-decyl urea, N-
[2- (p-hydroxyphenylthio) ethyl] carbamate-n-octadecyl, N- [p- (p-hydroxyphenylthio) phenyl] carbamate-n-dodecyl, Nn-octadecylcarbamate- [2 -(P-
Hydroxyphenylthio) ethyl], N- [3- (p-
Hydroxyphenylthio) propionyl] -N-n-octadecanoylamine, N- [2- (p-hydroxyphenylthio) aceto] -N'-n-octadecanohydrazide, N- [3- (p-hydroxy) Phenylthio) propiono] -N'-n-octadecanohydrazide, N-
[3- (3,4-dihydroxyphenylthio) propiono] -N'-n-octadecanohydrazide, N- [6-
(P-Hydroxyphenylthio) hexano] -N'-n
-Tetradecanohydrazide, N- [6- (p-hydroxyphenylthio) hexano] -N'-n-octadecanohydrazide, N- [6- (p-hydroxyphenylthio) hexano] -N '-( pn-octylbenzo) hydrazide, N- [11- (p-hydroxyphenylthio) undecano-N'-n-decanohydrazide, N-
[11- (p-hydroxyphenylthio) undecano-
N'-n-tetradecanohydrazide, N- [11- (p
-Hydroxyphenylthio) undecano-N'-n-octadecanohydrazide, N- [11- (p-hydroxyphenylthio) undecano-N '-(6-phenyl) hexanohydrazide, N- [11- (3 , 4,5-Trihydroxyphenylthio) undecano] -N'-n-octadecanohydrazide, N- [p- (p-hydroxyphenylthio) benzo] -N'-n-octadecanohydrazide, N- [P- (p-hydroxyphenylthiomethyl)
Benzo] -N'-n-octadecanohydrazide, N-
[3- (p-hydroxyphenylthio) propyl] -N
'-N-octadecyl oxamide, N- [3- (3,4
-Dihydroxyphenylthio) propyl] -N'-n-
Octadecyl oxamide, N- [11- (p-hydroxyphenylthio) undecyl] -N'-n-decyl oxamide, N- [p- (p-hydroxyphenylthio) phenyl] -N'-n-octadecyl oxamide, N-
[2- (p-hydroxyphenylthio) acetyl] -N
'-N-octadecyl urea, N- [3- (p-hydroxyphenylthio) propionyl] -N'-n-octadecyl urea, N- [2- (p-hydroxyphenylthio)
Ethyl] -N'-n-octadecanoyl urea, N- [p
-(P-hydroxyphenylthio) phenyl] -N'-
n-octadecanoyl urea, 3- [3- (p-hydroxyphenylthio) propionyl] carbazic acid-n-octadecyl, 4- [2- (p-hydroxyphenylthio) ethyl] -1-n-octadecyl semicarbazide,
1- [2- (p-hydroxyphenylthio) ethyl]-
4-n-octadecyl semicarbazide, 1- [p- (p
-Hydroxyphenylthio) phenyl] -4-n-tetradecyl semicarbazide, 1- [3- (p-hydroxyphenylthio) propionyl] -4-n-octadecyl semicarbazide, 1- [p- (p-hydroxyphenylthio) Benzoyl] -4-n-octadecyl semicarbazide, 4- [2- (p-hydroxyphenylthio) ethyl] -1-n-tetradecanoyl semicarbazide, 4-
[P- (p-hydroxyphenylthio) phenyl] -1
-N-octadecanoyl semicarbazide, 1- [2-
(P-Hydroxyphenylthio) acetamide] -1-
n-octadecanoylaminomethane, 1- [11- (p
-Hydroxyphenylthio) undecanamide] -N '
-N-decanoylaminomethane, 1- [p- (p-hydroxyphenylthio) benzamide] -1-n-octadecanoylaminomethane, 1- [3- (p-hydroxyphenylthio) propanamide] -1 -(N'-n-octadecylureido) methane, 1- [11- (p-hydroxyphenylthio) undecanamide] -N '-(N
'-N-decylureido) methane, 1- {N'-[2-
(P-Hydroxyphenylthio) ethyl] ureido}-
1-n-octadecanoylaminomethane, N- [2-
(P-Hydroxyphenylthio) ethyl] -N'-n-
Octadecyl malonamide,

N- [2- (p-hydroxyphenyl) ethyl] carbamate-n-octadecyl, Nn-octadecylcarbamate- [2- (p-hydroxyphenyl) ethyl], N- [3- (p -Hydroxyphenyl)
Propionyl] -N-n-octadecanoylamine, N
-[6- (p-hydroxyphenyl) hexanoyl]-
N-n-octadecanoylamine, N- [3- (p-hydroxyphenyl) propionyl] -N- (pn-octylbenzoyl) amine, N- [2- (p-hydroxyphenyl) aceto] -N '-N-dodecanohydrazide, N- [2- (p-hydroxyphenyl) aceto]-
N'-n-octadecanohydrazide, N- [3- (p-
Hydroxyphenyl) propiono] -N'-n-octadecanohydrazide, N- [3- (p-hydroxyphenyl) propiono] -N'-n-docosanohydrazide, N
-[6- (p-hydroxyphenyl) hexano] -N '
-N-tetradecanohydrazide, N- [6- (p-hydroxyphenyl) hexano] -N'-n-octadecanohydrazide, N- [6- (p-hydroxyphenyl) hexano] -N '-( p-n-octylbenzo) hydrazide, N- [11- (p-hydroxyphenyl) undecano-N'-n-decanohydrazide, N- [11- (p-
Hydroxyphenyl) undecano-N'-n-octadecanohydrazide, N- [p- (p-hydroxyphenyl) benzo] -N'-n-octadecanohydrazide, N
-[P- (p-hydroxyphenylmethyl) benzo]-
N'-n-octadecanohydrazide, N- [3- (p-
Hydroxyphenyl) propyl] -N'-n-octadecyloxamide, N- [3- (3,4-dihydroxyphenyl) propyl] -N'-n-octadecyloxamide, N- [p- (p-hydroxyphenyl) ) Phenyl]
-N'-n-octadecyl oxamide, N- [2- (p
-Hydroxyphenyl) acetyl] -N'-n-octadecylurea, N- [3- (p-hydroxyphenyl) propionyl] -N'-n-octadecylurea, N- [p
-(P-Hydroxyphenyl) benzoyl] -N'-n
-Octadecyl urea, N- [2- (p-hydroxyphenyl) ethyl] -N'-n-octadecanoyl urea, 4
-[2- (p-hydroxyphenyl) ethyl] -1-n
-Octadecyl semicarbazide, 1- [2- (p-hydroxyphenyl) ethyl] -4-n-tetradecyl semicarbazide, 1- [2- (p-hydroxyphenyl) ethyl] -4-n-octadecyl semicarbazide, 1-
[2- (p-hydroxyphenyl) acetyl] -4-n
-Tetradecyl semicarbazide, 1- [3- (p-hydroxyphenyl) propionyl] -4-n-octadecyl semicarbazide, 1- [11- (p-hydroxyphenyl) undecanoyl] -4-n-decyl semicarbazide, 4- [ 2- (p-hydroxyphenyl) ethyl]-
1-n-octadedecanoyl semicarbazide, 4- [p
-(P-hydroxyphenyl) phenyl] -1-n-octadecanoyl semicarbazide, 1- [2- (p-hydroxyphenyl) acetamido] -1-n-octadecanoylaminomethane, 1- [3- (p -Hydroxyphenyl) propanamide] -1-n-octadecanoylaminomethane, 1- [2- (p-hydroxyphenyl) acetamide] -1- (3-n-octadecylureido)
Methane, 1- [3- (p-hydroxyphenyl) propanamide] -1- (3-n-octadecylureido) methane, 1- [11- (p-hydroxyphenyl) undecaneamide] -1- (3-n -Decylureido) methane, 1- {3- [2- (p-hydroxyphenyl) ethyl] ureido} -1-n-octadecanoylaminomethane, N- [2- (p-hydroxyphenyl) ethyl]-
N'-n-octadecyl malonamide,

4-n-octadecylaminophenol,
4- (1-octadecynyl) phenol, 4- (1,3
-Octadecadiynyl) phenol and the like.

These may be used alone or in admixture of two or more, and usually 5 to 5000% by weight, preferably 10 to 3000% by weight, based on the colorless or light-colored electron-donating dye precursor. Used.

It is also possible to add a binder to the above dispersion for the purpose of improving the strength of the reversible thermosensitive recording layer. Specific examples of the binder include starches,
Hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylic acid amide / acrylic acid ester copolymer, acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer , Water-soluble polymer such as alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylic acid ester, styrene / butadiene copolymer, acrylonitrile Examples thereof include latexes such as / butadiene copolymer, methyl acrylate / butadiene copolymer, and ethylene / vinyl acetate copolymer, but are not limited thereto.

A heat-fusible substance can be contained in the reversible thermosensitive recording layer as an additive for controlling the color developing sensitivity and the decoloring temperature of the reversible thermosensitive recording layer. 60 ° C
Those having a melting point of ~ 200 ° C are preferable, and especially 80 ° C.
Those having a melting point of ˜180 ° C. are preferred. It is also possible to use a sensitizer which is used in general thermal recording paper.

For example, waxes such as N-hydroxymethylstearic acid amide, stearic acid amide and palmitic acid amide, naphthol derivatives such as 2-benzyloxynaphthalene, biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl, 1,2-bis (3-methylphenoxy) ethane, 2,2'-bis (4
-Methoxyphenoxy) diethyl ether, bis (4-
Polyether compounds such as methoxyphenyl) ether,
Carbonic acid such as diphenyl carbonate, dibenzyl oxalate, oxalic acid bis (p-methylbenzyl) ester, or an oxalic acid diester derivative can be added in combination, but the addition is not limited thereto.

In the present invention, a colored layer may be provided on the reversible thermosensitive recording layer with an intermediate layer interposed. The intermediate layer is effective when an organic solvent is used at the time of forming the colored layer, has a role of preventing permeation of the organic solvent into the recording layer, and providing a product having no coloring defect. The resin used for the intermediate layer is not particularly limited, but various conventionally known water-soluble and water-insoluble polymers are used.

Specific examples of the water-soluble polymer include polyvinyl alcohol, modified polyvinyl alcohol, starch and its derivatives, methylcellulose or cellulose derivatives such as methoxycellulose or hydroxyethylcellulose, casein, gelatin, polyvinylpyrrolidone,
Styrene-maleic anhydride copolymer, diisobutylene-
Maleic anhydride copolymer, polyacrylamide, modified polyacrylamide, methyl vinyl ether-maleic anhydride copolymer, carboxy-modified polyethylene, polyvinyl alcohol-acryloamide copolymer, melamine-formaldehyde resin, urea-formaldehyde resin, and the like. . These water-soluble polymers are used in the form of aqueous solutions. Specific examples of the non-aqueous polymer include polyvinyl acetate, polyurethane, styrene-butadiene copolymer, styrene-butadiene-acrylic copolymer, polyacrylic acid, polyacrylic ester, vinyl chloride-vinyl acetate copolymer. , Polybutyl methacrylate, ethylene-vinyl acetate copolymer and the like. These water-insoluble polymers are used in the form of aqueous emulsion. The polymers may be used alone or as a mixture, and if necessary, a curing agent may be added to cure the resin.

The support used in the reversible thermosensitive recording material of the present invention includes paper, coated paper, various non-woven fabrics, woven fabrics, synthetic resin films, synthetic resin laminated papers, synthetic papers, metal foils, glass, etc., or A composite sheet in which these are combined can be optionally used according to the purpose, and may be transparent, semi-transparent or opaque.
It is not limited to these. The thickness of the support is not particularly limited as long as it can withstand repeated use, but is 20 to 1300 μm, preferably 40 to 100 μm.
It is about 0 μm.

In the present invention, an undercoat layer may be interposed between the support and the recording layer, if necessary. The undercoat layer is used for the purpose of improving heat insulation, improving the adhesion between the support and the recording layer, improving the resistance of the support to the solvent during recording preparation, and preventing the support from absorbing the heat-melting substance when heat is applied. Is installed. One of the important roles of the undercoat layer is to improve the heat insulating property, and this is to make the applied heat energy useful for forming and erasing recording without waste. By providing the heat-insulating undercoat layer, coloring and decoloring can be performed sharply. The heat insulating undercoat layer may be formed by coating fine hollow particles made of an organic or inorganic material on a support. Specifically, the heat insulating undercoat layer is formed of glass, ceramics, plastic, or the like and has a particle size of about 1 to 50 μm. The fine hollow body may be well dispersed in a solvent together with a binder resin, and uniformly coated and dried on the support. When the support is a substance such as paper that easily absorbs liquid, an undercoat layer that does not allow liquid to permeate may be formed, and when a support soluble in a recording layer forming solvent is used. For the above, an undercoat layer insoluble in the solvent may be provided on the support.

The method of forming each layer constituting the reversible thermosensitive recording material of the present invention on the support is not particularly limited, and it can be formed by a conventional method. For example,
Coating equipment such as air knife coater, blade coater, bar coater, carter coater, planographic printing, letterpress printing, intaglio printing, flexo, gravure, screen, hot melt, etc. It is possible to use various printing machines, etc. Furthermore, in addition to the usual drying process, each layer can be held by UV irradiation / EB irradiation. By these methods, one layer or multiple layers can be coated and printed simultaneously.

In the reversible thermosensitive recording material of the present invention, in order to form a color-developed recording image, rapid cooling after heating is required, and in order to erase the recorded image, the cooling rate after heating is slow. Good. For example, the color-developed state can be developed by heating the material by an appropriate method and then rapidly cooling it by pressing a low-temperature metal block or the like. In addition, when a thermal head, a laser beam or the like is used for heating for an extremely short period of time, it is cooled immediately after the heating is completed, so that the coloring state can be maintained. on the other hand,
Suitable heat source (thermal head, laser light, heat roll,
Radiant heat from heat stamps, high frequency heating, electric heaters, and light sources such as tungsten lamps and halogen lamps,
When heated with hot air) for a relatively long period of time, not only the recording layer but also the support and the like are heated, so that the cooling speed is slow even if the heat source is removed, resulting in a decolored state. Therefore, even if the same heating temperature and / or the same heat source is used, the colored state and the decolored state can be arbitrarily expressed by controlling the cooling rate.

[0085]

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

Example 1 (A) Preparation of reversible heat-sensitive coating liquid 40 parts of 3-di-n-butylamino-6-methyl-7-anilinofluorane, which is a dye precursor, in 2.5% polyvinyl alcohol aqueous solution. It was pulverized together with 90 parts by a ball mill for 24 hours to obtain a dye precursor dispersion liquid. Then N- [3-
(P-Hydroxyphenyl) propiono] -N'-n-
100 parts of octadecanohydrazide was pulverized with 400 parts of 2.5% aqueous solution of polyvinyl alcohol in a ball mill for 24 hours to obtain a dispersion liquid. After mixing the above two dispersions,
200 parts of 10% polyvinyl alcohol aqueous solution, 400 water
Parts were added and mixed well to prepare a reversible heat-sensitive coating liquid.

(B) Coating of reversible thermosensitive recording layer The reversible thermosensitive coating liquid prepared in (A) was applied to a polyethylene terephthalate (PET) sheet as a support so that the solid coating amount was 4 g / m ² . The coated sheet was dried, and then treated with a super calendar to obtain a coated sheet B.

(C) Coating of Colored Layer On the coating layer of the coated sheet B obtained in (B), an oil-soluble dye (orange:
Yamamoto Kasei; # 816) A coating liquid consisting of 20 parts by weight, 100 parts by weight of polyester resin, and 300 parts by weight of tetrahydrofuran is applied and dried to give a solid content of 1.5 g / m ^2, and a colored layer is applied. Work sheet C was obtained.

(D) Coating of protective layer On the coating layer of the coating sheet C obtained in (C), Aronix M
8030 (manufactured by Toagosei Chemical Industry Co., Ltd.) 85 parts, N-vinyl-
2-Pyrrolidone 5 parts, Irgacure 500 (manufactured by Nippon Ciba Geigy) 5 parts, and Mizukasil P-527 (manufactured by Mizusawa Chemical Co., Ltd.) 5 parts were added and sufficiently stirred to obtain an ultraviolet curable resin of 1.5.
After coating so as to be g / m ² , the coating was cured with an ultraviolet irradiation device (Rapid Cure, manufactured by Ushio Inc.) to obtain a reversible thermosensitive recording material having a protective layer.

Example 2 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the coating of the (C) colored layer in Example 1 was changed as follows.

(C) Coating of Colored Layer On the coating layer of the coated sheet B obtained in (B), an oil-soluble dye (green:
Yamamoto Kasei; # 890) 5 parts by weight, vinyl chloride resin 10
0 parts by weight and 300 parts by weight of tetrahydrofuran were applied and dried to give a solid content of 5.0 g / m ² ,
A coating layer C was obtained by providing a colored layer.

Example 3 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the coating of the (C) colored layer in Example 1 was changed as follows.

(C) Coating of UV Absorbing Layer On the coating layer of the coating sheet B obtained in (B) of Example 1, 1 part by weight of an oil-soluble dye (blue: Nippon Ciba-Geigy; Orazol GN) was added. A coating liquid consisting of 100 parts by weight of vinyl resin and 300 parts by weight of tetrahydrofuran is applied to a solid content of 0.5 g / m ²
And dried to obtain a colored layer.

Example 4 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the coating of the (C) colored layer in Example 1 was changed as follows.

(C) Formation of UV Absorbing Layer On the coating layer of the coating sheet B obtained in (B) of Example 1, 10 parts by weight of a color pigment (yellow: manufactured by Mikuni pigment; Yellow 10GN), 100 parts by weight of polyvinyl alcohol. Parts and 500 parts by weight of water were applied and dried to give a solid content of 2.5 g / m ^2, and a colored layer was applied.

Comparative Example 1 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the coating of the (C) colored layer in Example 1 was changed as follows.

(C) Coating of UV Absorbing Layer On the coating layer of the coating sheet B obtained in (B) of Example 1, an oil-soluble dye (yellow: Nippon Ciba Geigy; Orazol 2GLN) was applied.
1 part by weight, 100 parts by weight of polyester resin, and 300 parts by weight of tetrahydrofuran were used to apply a solid content of 0.
The colored layer was applied by coating and drying so that the coating amount was 4 g / m ² .

Comparative Example 2 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the coating of the (C) colored layer in Example 1 was changed as follows.

(C) Formation of UV Absorbing Layer On the coating layer of the coating sheet B obtained in (B) of Example 1, 10 parts by weight of an oil-soluble dye (blue: manufactured by Yamamoto Kasei; # 15) and vinyl chloride were added. A coating liquid consisting of 100 parts by weight of the resin and 300 parts by weight of tetrahydrofuran was applied and dried so that the coating amount of the solid content was 6.0 g / m ^2, and the colored layer was applied.

Comparative Example 3 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the coating of the (C) colored layer in Example 1 was changed as follows.

(C) Formation of UV Absorbing Layer On the coating layer of the coating sheet B obtained in (B) of Example 1, 25 parts by weight of a color pigment (orange: Mikuni dye; Orange BO), styrene-butadiene were used. 100 parts by weight of latex,
A coating liquid consisting of 500 parts by weight of water is applied to a solid content of 1.5 g / m ²
And dried to obtain a colored layer.

Comparative Example 4 (C) The coloring layer (C) of Example 1 was not applied, except that
A reversible thermosensitive recording material was obtained in the same manner as in Example 1.

Test 1 (Coloring Density) The thermal recording materials obtained in the examples and comparative examples were applied with the application pulse 1. using an Okura Electric thermal printing facsimile TH-PMD with a Kyocera print head KJT-256-8MGF1. Printing was performed for 1 millisecond under an applied voltage of 26 V, and the density of the obtained color image was measured with a densitometer Macbeth RD91.
8 was used for measurement. The results are shown in Table 1.

Test 2 (Color difference between erased portion and unprinted portion before light exposure) 12 was applied to the colored image portion obtained in Test 1 using a heat stamp.
After heating at 0 ° C. for 1 second, the color difference between the erased portion and the image non-formed portion was measured. Color difference is Minolta color difference meter CR-20
It was evaluated by measuring the color difference ΔE before and after light exposure at 0. The results are shown in Table 1.

Test 3 (Color difference between erased part and unprinted part after exposure to light) The reversible thermosensitive recording materials obtained in Examples and Comparative Examples were put in a xenon fade meter at 1 after the image erasing operation shown in Test 2. After exposure for a period of time, the color difference between the erased portion and the image-unformed portion was measured. The results are shown in Table 1.

Test 4 (Visibility of erased portion) An image was formed again on the erased portion of the samples of Examples and Comparative Examples after light exposure obtained in Test 3 and observed and evaluated. The results are shown in Table 1.
It was shown to. ◯: The visibility of the erase mark is low and does not affect the sharpness of the re-formed image. Δ: Does not affect the sharpness of the re-formed image,
The erasure mark can be identified. X: Erased marks are conspicuous, and the sharpness of the re-formed image is impaired.

[0110]

[Table 1]

With the reversible thermosensitive recording materials obtained in Examples 1 to 4, it was difficult to visually recognize the erased portion even after exposure to light, and the sharpness of the image formed again was not adversely affected. On the other hand, in Comparative Examples 1 and 4, the erased portion could be easily discriminated after exposure to light, and sharpness of the re-formed image was significantly lowered.
In Comparative Examples 2 and 3, the heat conduction efficiency of image formation was deteriorated due to the formation of the coloring layer, which was a practically problematic level in terms of color density. From this, a clear difference is observed between the example and the comparative example, and it is confirmed that the present invention has a great effect.

[0112]

INDUSTRIAL APPLICABILITY The reversible thermosensitive recording material of the present invention can be colored by heat energy of a thermal head or the like, and can be changed to a decolored state by heating the composition in the colored state again. Further, such coloring and erasing can be repeated, and the coloring and erasing states can be maintained at room temperature. Further, in the reversible thermosensitive recording material of the present invention, a colored layer comprising a colored dye or a colored pigment and a binder resin is provided on the reversible thermosensitive recording layer, and an ultraviolet curable resin is formed on the colored layer. A protective layer is provided. As a result, it becomes possible to reduce the visibility of the erased portion due to light exposure and maintain the sharpness of the image formed again.

Claims (2)

[Claims] 1. A usually colorless or pale-colored electron-donating dye precursor and a reversible developer that causes the dye precursor to develop color by heating and decolors by reheating the dye on at least one side of the support. In a reversible thermosensitive recording material provided with a reversible thermosensitive recording layer containing, a colored layer comprising a coloring dye or a coloring pigment and a binding resin, and a protective layer comprising an ultraviolet curable resin are provided on the reversible thermosensitive recording layer. A reversible thermosensitive recording material characterized by being sequentially laminated. 2. The reversible thermosensitive recording material according to claim 1, wherein the colored layer has a solid coating amount of 0.5 to 5 g / m ² .