JPH07285271A - Reversible thermal recording material - Google Patents

Abstract

PURPOSE:To provide a reversible thermal recording material capable of forming and erasing an image in good contrast, capable of holding an image stable with the elapse of time not only under environment of dairy life but also under a heating condition and excellent in sensitivity and repeating durability. CONSTITUTION:In a reversible thermal recording material wherein a reversible thermal layer based on a usually colorless or lightcolored dye precursor and a reversible coupler causing a reversible color change in the dye precursor by the difference in cooling speed after heating is provided on a support, an amine compd. is added to the reversible thermal 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 capable of forming and erasing an image by controlling thermal energy.

[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-45-
No. 14039 is disclosed.

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. Also, the sensitivity was 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 / reducing agent is an amphoteric mixture in which a molecule having an acidic group for coloring the leuco dye and a molecule having a basic group for decoloring the colored leuco dye are combined or bonded by an ionic bond. One of the coloring action by the group and the decoloring action by the basic group is preferentially generated to perform the coloring and the decoloring. However, in this method, it is not possible to completely switch the coloring reaction and the erasing reaction only by controlling the thermal energy, and since both reactions occur at a certain ratio at the same time, sufficient coloring density cannot be obtained, and the erasing Can not be done completely. Therefore, sufficient image contrast cannot be obtained. Further, since the decoloring action of the basic group also acts on the color-developed portion at room temperature, it is inevitable that the density of the color-developed portion will decrease over time.

As described above, according to the conventional technique, there is a reversible thermosensitive recording material having a good image contrast, capable of forming / erasing an image, and capable of holding a stable image over time in the environment of daily life. I didn't. However, the present applicant has proposed a reversible heat-sensitive recording material using a novel reversible developer in Japanese Patent Application No. 347032/1992. With this, it has a good image contrast and can form and erase images.
A reversible thermosensitive recording material capable of holding a stable image with time in an environment of daily life was first proposed.

However, in order to further improve the image storability and further lower the optical density of the erasable portion (improve the erasability), it was still necessary to study the reversible thermosensitive layer component. Therefore, the addition components were examined.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to form and erase an image with a good contrast, and keep a stable image with time not only under the environment of daily life but also under heating conditions. And to provide a reversible thermosensitive recording material having excellent sensitivity and decoloring property.

[0011]

Means for Solving the Problems As a result of research to solve this problem, the present inventors have found that a colorless or light-colored dye precursor is usually present on a support and that the cooling rate after heating causes a difference. In a reversible thermosensitive recording material provided with a reversible thermosensitive layer containing a reversible developer that causes a reversible color change in a dye precursor, an image can be obtained by including an amine compound in the reversible thermosensitive layer. It was found that a reversible thermosensitive recording material having excellent storage stability and decoloring property was obtained, and the present invention was completed.

The general formula of the preferred amine compound in the present invention is shown in the following chemical formula 1. It was unexpected that a basic compound such as Chemical formula 1 contributes to the improvement of storage stability. When an amine compound is used in a general thermal paper using a basic dye precursor and an acidic developer, the image storability is usually lowered.

[0013]

[Chemical 1]

However, in Chemical formula 1, W, Y and Z represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group or an aralkyl group. Any one or more of W, Y and Z may be bonded to form a ring. In addition, W, Y, and Z are not all hydrogen atoms.

When W, Y and Z are other than a hydrogen atom, a substituent such as an alkyl group is further substituted on the substituent such as a hydroxy group, a thio group, an alkyl group, an aralkyl group, an aminocarbonyl group, an alkoxy group and a halogen atom. , A cyano group, a nitro group, a formyl group, an alkoxycarbonyl group, an aminocarbonyl group, or the like, or a linking group may be inserted in an alkyl chain or the like. There may also be unsaturated bonds or cyclic moieties. Further, one or more carbon atoms of the hydrocarbon group constituting W, Y and Z may be replaced with a hetero atom. Examples of the hetero atom include an oxygen atom, a nitrogen atom and a sulfur atom. Further, it may be substituted with an atomic group containing a hetero atom such as sulfone. Specific examples will be given below individually.

Specific examples of the alkyl group represented by W, Y and Z include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, secondary butyl group and tertiary butyl group. Group, n-pentyl group, n-hexyl group,
n-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, n-tetradecyl group, n-hexadecyl group, n-octadecyl group, n-eicosyl group, n
-Docosyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, allyl group, propargyl group, 2-aminoethyl group, 2-dimethylaminoethyl group, 2- (4-morpholino) ethyl group, tetrahydrofurfuryl group, 2-
Ethoxyethyl group, methoxycarbonylmethyl group, ethoxycarbonylmethyl group, aminocarbonylmethyl group,
2-aminocarbonylethyl group and the like can be mentioned. W,
Specific examples of the cycloalkyl group represented by Y and Z include
Examples include a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cyclododecyl group, a 7,7-dimethylnorbornan-2-yl group, a 1-adamantyl group, a 2-adamantyl group, a cholesteryl group, and a 4-piperidino group. . Specific examples of the aralkyl group represented by W, Y and Z include benzyl group, cinnamyl group,
2-phenoxyethyl group, p-methylbenzyl group, p-
A chlorobenzyl group, a benzhydryl group, a triphenylmethyl group, a 1-naphthylmethyl group and the like can be mentioned. W,
Specific examples of the aryl group represented by Y and Z include a phenyl group, a p-methylphenyl group, a p-methoxyphenyl group, a 1-naphthyl group and a 2-naphthyl group.

When the substituents represented by W, Y and Z are bonded to each other, examples thereof include a bifunctional group such as a methylene group, an ethylene group and a phenylene group, and a trifunctional group such as a methine group. . Also, when the bond between the nitrogen atom and W, Y is a double bond, it is one of the examples in which W, Y are bonded. Imines and aromatic bases produced in that case are also included in the amine compound in the present invention.

Next, a more preferable case of the compound represented by Chemical formula 1 will be described. Even when any one or more of W, Y, and Z contains an aromatic ring, it is preferable that the number of aromatic rings is 2 or less, particularly 1, in the same molecule in order to further improve the storage stability. It is more preferable if none of W, Y and Z contains an aromatic ring. The fused aromatic ring is calculated, for example, by the number of monocycles that are composed of two benzene rings for a naphthalene ring and three benzene rings for an anthracene ring.

Among the amine compounds represented by Chemical formula 1, polyamine compounds having a valence of 3 or more, particularly a valence of 4 or more, are more preferable for improving image storability. The boiling point or sublimation point of the compound represented by Chemical formula 1 is preferably 200 ° C. or higher for repeated use.

The preferred lower limit of the addition amount of the amine compound represented by Chemical formula 1 is 0.5% by weight or more based on the dye precursor.
Particularly, it is 5% by weight or more. If it is less than 0.5% by weight, the effect is insufficient. Also, the upper limit is 1000 with respect to the dye precursor.
It is below wt%, especially below 300 wt%. If it exceeds this range, color development failure and sensitivity drop occur.

Next, specific examples of the compound represented by Chemical formula 1 will be given.

Hexamethylenetetramine, benzoguanamine, guanidine, dicyandiamide, 1,3-diphenylguanidine, 1,2,3-triphenylguanidine, 1,3-dicyclohexyl-2-p-tolylguanidine, 1,3-di-o. -Tolylguanidine, diethylenetriamine, triethylenetetramine, hexamethylenediamine, quinuclidine, N-stearyldimethylamine, N-stearylmethylamine, cholesterylamine, 4,4'-diaminodiphenylmethane, theophylline, theobromine, dodecamethylenediamine, melamine, 2 , 4,6-triaminopyrimidine, 1,3-dipiperidyl propane, N- (2-dimethylaminoethyl)
-N'-methylpiperazine, 2,2'-bipyridyl,
4,4'-bipyridyl, nicotine, N, N, N ', N'
-Tetrakis (2-hydroxypropyl) ethylenediamine, 1,1-bis (N-morpholino) ethylene, adenine, 8-azaadenine, 2,3,3-trimethylindolenine, adenosine, 2-aminopurine, 6-aminopurine, 2-aminopyrazine, 1-anilinonaphthalene, 2-anilinonaphthalene, 3-anilinopropionitrile, triphenylamine, tribenzylamine, N
-Benzyl-N-ethylaniline, N-benzyl-2-
Methylimidazole, N-benzylpiperazine, tristearylamine, stearylamine, distearylamine, 4-benzylpyridine, 4-aminoantipyrine,
2-aminobenzimidazole, 4-dimethylaminobenzaldehyde, methyl 4-aminobenzoate, ethyl 4-aminobenzoate, benzyl 4-aminobenzoate, 2-
Aminobenzothiazole, 1,4-dianilinobenzene, 4-anilino-3-methylanisole, 4- (2-
(Chloroanilino) anisole, 4-chloro-2-aminoanisole, 2-amino-6-ethoxybenzothiazole, 3-trifluoromethyl-4-chloroaniline, carbazole, indole, benzimidazole, 5-aminoindazole, cinchonidine, cinchonine, 1,
2-diaminocyclohexane, 2,4-diamino-6-
Methyl-s-triazine, 6-aminoindazole, 6
-Amino-2,4-lutidine, 2-amino-6-methoxybenzothiazole, 2-amino-6-methylbenzothiazole, 1-amino-4-methylpiperazine, 4-amino-2-methylquinoline, 2-amino -6-nitrobenzothiazole, 5,6-dimethylbenzimidazole, 2-phenylbenzimidazole, 2-phenylindole, 2-phenylimidazole, 2-phenylimidazoline, quinoline, quinoxaline, N-phenylmorpholine, 2,3-dimethyl Indole, 4-amino-
2-chlorotoluene, 2-amino-6-chlorotoluene, triethanolamine, diethanolamine, diisopropanolamine, 1,3-di (4-pyridyl) propane, 4,4'-dithiodianiline, monoethanolamine, 2 -Dimethylaminoethanol, 1,3-bis (N-morpholino) -2-nitropropane, DL-α-
Amino-ε-caprolactam, 4-chloro-2-trifluoromethylaniline, N- (2-dimethylaminoethyl) morpholine, 2,4,6-trimethyl-1,3,5
-Triazine, histamine, paraphenylenediamine,
Metaphenylenediamine. You may use these individually or in mixture of 2 or more types.

As the dye precursor used in the reversible thermosensitive layer according to the present invention, a basic dye precursor used for recording materials such as general thermal paper and pressure-sensitive paper can be used.
Specific examples of the dye precursor used in the present invention are shown below, 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- (N-ethyl-N-tolyl) amino-6-methyl-7-anilinofluorane, 3
-(N-ethyl-N-tolyl) amino-6-methyl-7
-Phenethylfluorane, etc.

(4) Spiro compound 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran, 3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3 -Methoxybenzo) spiropyran, 3-propylspirobenzopyran, etc.,

(5) 2- (or 7-) anilinofluorane compound 3-diethylamino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl-7-anilinofluorane, 3 -Pyrrolidino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7- (4
-Methylanilino) fluorane, 3-diethylamino-
6-methyl-7- (4-n-butylanilino) fluorane, 3-diethylamino-6-methyl-7- (4-ethoxyanilino) fluorane, 3-pyrrolidino-6-methyl-7- (4-methylanilino) fluorane , 3-pyrrolidino-6-methyl-7- (4-n-butylanilino)
Fluoran, 3-pyrrolidino-6-methyl-7- (4-
Ethoxyanilino) fluorane, 3-di-n-propylamino-6-methyl-7-anilinofluorane, 3-di-n-butylamino-6-methyl-7-anilinofluorane, 3-di- n-pentylamino-6-methyl-7-
Anilinofluorane, 3- (N-methyl-Nn-propyl) amino-6-methyl-7-anilinofluorane,
3- (N-ethyl-Nn-propyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N)
-Isoamyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isobutyl) amino-
6-methyl-7-anilinofluorane, 3- (N-methyl-N-cyclohexyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-tetrahydrofuran-2-ylmethyl) Amino-6-methyl-7-
Anilinofluorane, 3- (N-ethyl-N-tetrahydrofurylmethyl) amino-6-methyl-7-anilinofluorane, 3- (N-methyl-N-tetrahydrofuran-2-yl) amino-6- Methyl-7-anilinofluorane, 3- (N-ethyl-N-tetrahydrofuryl)
Amino-6-methyl-7-anilinofluorane, 3-dimethylamino-6-methyl-7-anilinofluorane,
3- (N-methyl-N-ethyl) amino-6-methyl-
7-anilinofluorane, 3-isopentylamino-6
-Methyl-7-anilinofluorane, 3-di-n-butylamino-6-methyl-7- (2-fluoroanilino)
Fluoran, 3-dibutylamino-6-methoxy-7-
Anilinofluorane, 3-di-n-butylamino-6-
Methyl-7- (2,6-dimethylanilino) fluorane, 3- (N-ethyl-N-3-ethoxypropyl) amino-6-methyl-7-anilinofluorane, 3- (N
-Methyl-N-3-ethoxypropyl) amino-6-methyl-7-anilinofluorane, 3-diethylamino-
6-methyl-7- (3-trifluoromethylanilino)
Fluorane, 3-diethylamino-7- (3-trifluoromethylanilino) fluorane, 3-diethylamino-7- (2-chloroanilino) fluorane, 3-diethylamino-7- (3-chloroanilino) fluorane, 3
-Diethylamino-7- (2-fluoroanilino) fluorane, 3-diethylamino-7- (2-methoxyanilino) fluorane, 3-pyrrolidino-7- (2-chloroanilino) fluorane, 3-pyrrolidino-7- (3 -Chloroanilino) fluorane, 3-pyrrolidino-7- (2
-Methoxyanilino) fluorane, 3-diethylamino-7- (2-isopentyloxycarbonylanilino)
Fluoran, 3- (N-ethyl-Np-tolyl) amino-6-methyl-7-anilinofluorane,

(6) Other fluorane compounds 3-pyrrolidino-7-cyclohexylaminofluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-7-n-octylaminofluorane, 3-diethylamino- 7-phenylfluorane, 3-diethylamino-7-chlorofluorane, 3-
Diethylamino-6-chloro-7-methylfluorane,
3-diethylamino-6-methyl-7-chlorofluorane, 3-diethylamino-7- (3,4-dichloroanilino) fluorane, 3-ethylamino-6-chlorofluorane, 3-cyclohexylamino-6-chloro Fluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-di-n-butylamino-7- (2-chlorobenzylamino) fluorane,

(7) Compounds of other structures 3- (4-dimethylaminophenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, 3-
Indolylphthalide such as (4-dimethylaminophenyl) -3- (1,2-dimethylindol-3-yl) phthalide and 3,3-bis (1-ethyl-2-methylindol-3-yl) phthalide Kind. 3 ', 6'-bisdiethylamino-5-diethylaminospiro (isobenzofuran-1,9'-fluorene) -3-one, 3', 6 '
-A compound having a fluorene skeleton such as bisdimethylamino-5-dimethylaminospiro (isobenzofuran-1,9'-fluorene) -3-one. 3,3-bis- [2-
Examples thereof include vinylogous compounds of triarylmethane compounds such as (4-methoxyphenyl) -2- (4-dimethylaminophenyl) ethenyl] -4,5,6,7-tetrachlorophthalide, and these are independent. Alternatively, two or more kinds can be mixed and used.

The reversible color developer used in the present invention is a phosphonic acid as long as it causes a reversible change in color tone that can be retained by a difference in cooling rate after heating in the presence of the dye precursor. Derivatives, carboxylic acid derivatives, phenol derivatives such as 4-hydroxybenzoic acid esters, 4-hydroxybenzoic acid amides and 4-hydroxyphenyl sulfides can be used without particular limitation. From the viewpoint of color density and decoloring property, Japanese Patent Application No.
Those represented by the following general formula 2 including those described in No. 347032 are preferably used.

[0032]

[Chemical 2]

In the formula 2, 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 via a nitrogen atom, a divalent group containing two or more hetero atoms,
Alternatively, it represents a divalent group containing an unsaturated bond or an aromatic ring. R represents an aliphatic hydrocarbon group. Of the atoms contained in X and R, the total number of atoms excluding hydrogen atoms and the atoms constituting the aromatic ring is 8 or more.

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, aliphatic hydrocarbon group such as allyl group, 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 represented by X which is bonded to the aromatic ring represented by A through a nitrogen atom include:
-NHCO-, -NH-, -NHCONH-, -NHC
ONHNH-, -NHCONHNHCONH-, -N =
CH -, - N = N - , - NHSO 2 - and the like. When a hydrogen atom is bonded to nitrogen, the hydrogen atom may be replaced 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, in the case of an amide bond, when the carbonyl group is bonded to the aromatic ring represented by A, either the decoloring property or the image density is unsatisfactory.

Examples of the divalent group represented by X containing two or more heteroatoms include --SO ₂ NH-- and --S--S.
-, - CONHNH -, - CONHCH 2 NHCO-,
-CONHNHCO-, -CONHNHCONH-,-
CH ₂ CH ₂ NHCONH-, and the like. The hetero atom as used herein is any atom other than a hydrogen atom, a carbon atom, and an oxygen atom, and can be a constituent atom of a divalent or higher valent linking group. Specific examples of the hetero atom include a nitrogen atom,
Examples thereof include sulfur atom, phosphorus atom, boron atom, silicon atom, selenium atom, fluorine atom, chlorine atom, bromine atom, iodine atom and tin atom.

As an example of the divalent group represented by X, which contains an unsaturated bond or an aromatic ring, --CH =
CH -, - CH = N - , - SO 2 -, a phenylene group, a carbon - group containing a carbon triple bond, a group formed by combining them,
Further, on one or both sides thereof, -NHCO-, -NH-, -NHCONH-, which are mentioned as other examples of X above,
-NHCSNH-, -N = CH-, -N = N-, -NH
Examples thereof include groups combining one or more linking groups such as SO ₂ —, —SO ₂ NH—, and —S—S—. In this case, other than the linking group, -CONH-, -O-, -S
-, -COO-, -OCO-, -OCOO-, -CO-
And a divalent group such as --SO _2- .

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 and cholesteryl 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.

The compound represented by the general formula 2 is an electron-accepting compound, and has a decolorizing ability specifically even though it has an ability to color the dye precursor, and exhibits a reversible effect. Incidentally, electron-accepting compounds used in ordinary heat-sensitive recording materials, that is, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl)
No such reversible effect is observed with sulfone, benzyl 4-hydroxybenzoate and the like. Next, specific examples of the reversible color developing agent that is 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'-hydroxytridecaneanilide, 4'-hydroxyheptadecaneanilide, 4'-hydroxynonadecaneanilide, 3'-hydroxynonadecaneanilide, 4'-hydroxy-10-octadecene Anilide, 4'-hydroxy-docassananilide, 15-cyclohexyl-4'-
Hydroxy pentadecane anilide, 4'-hydroxy-
5-Tetradeceneanilide, 4'-hydroxy-3'-
Methylnonaneanilide, 3'-cyclohexyl-4'-
Hydroxyheptadecane anilide, 3'-allyl-4 '
-Hydroxypentadecaneanilide, 4'-hydroxy-3'-methoxyoctadecaneanilide, 3'-chloro-4'-hydroxyoctadecaneanilide, 3'-hydroxydodecaneanilide, 2 ', 4'-dihydroxyheptadecaneanilide,

4'-hydroxy-4-hexylbenzanilide, 4'-hydroxy-4-dodecylbenzanilide, 4'-hydroxy-4-tetradecylbenzanilide, 4'-hydroxy-4-octadecylbenzanilide, 4 '. -Hydroxy-4-pentadecylaminocarbonylbenzanilide, 4'-hydroxy-4-hexylcarbonylaminobenzanilide, 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- Pentadecylideneamino) benzanilide, 4'-hydroxy-4- (N-heptadecylideneamino) benzanilide,

4'-hydroxy-3,4-dioctyloxybenzanilide, 4'-hydroxy-3,4,5-
Trioctadecyloxybenzanilide, 4'-hydroxy-3-octyl-4- (octylthio) benzanilide, 4'-hydroxy-3- (heptadecylthio)-
5-pentadecyloxybenzanilide, 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-docosyri) Denamino) Benzanilide,

4'-hydroxy-4-octadecylcarbonylaminobenzanilide, 4'-hydroxy-3-
Octadecylcarbonylamino-5-octadecyloxybenzanilide, 4'-hydroxy-3'-methyl-
4-nonylbenzanilide, 3'-allyl-4'-hydroxy-4-pentadecylbenzanilide, 4'-hydroxy-3'-methoxy-4-octadecylbenzanilide, 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'-dihydroxy-4-heptadecylsulfonyloxybenzanilide, 3', 4 ', 5'-trihydroxy-4-tetracosylaminosulfonylbenzanilide, 3 ', 5'-dihydroxy-4-pentacosylaminocarbonylbenzanilide, 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, 4-hydroxy-4'-tetradecylbenzanilide, N-methyl-4-hydroxy-4'-octadecylbenzanilide, 4-hydroxy-4'-octyloxy Benzanilide, 4-hydroxy-4'-octadecyloxybenzanilide, 4-hydroxy-4'-
(Octadecylthio) benzanilide, 4-hydroxy-4'-pentylcarbonylbenzanilide, 4-hydroxy-4'-hexadecylcarbonylbenzanilide, 4-hydroxy-4'-heptadecyloxycarbonyloxybenzanilide, 4-hydroxy- 4'-dodecyloxycarbonylbenzanilide, 4-hydroxy-4'-docosyloxycarbonylbenzanilide,
4-hydroxy-4'-heptadecylcarbonyloxybenzanilide, 4-hydroxy-4'-cyclohexylaminobenzanilide, 4-hydroxy-4'-octylaminobenzanilide, 4-hydroxy-4'-octadecylaminobenzanilide,

4-hydroxy-4'-heptylcarbonylaminobenzanilide, 4-hydroxy-4'-heptadecylcarbonylaminobenzanilide, 4-hydroxy-4'-octadecylaminocarbonylbenzanilide, 4-hydroxy-4'- (8-octadecenyl)
Aminocarbonylbenzanilide, 4-hydroxy-
4'-dodecylsulfonylbenzanilide, 4-hydroxy-4'-octyloxysulfonylbenzanilide, 4-hydroxy-4'-octadecyloxysulfonylbenzanilide, 4-hydroxy-4'-dodecylsulfonyloxybenzanilide, N-4 -Hydroxybenzoyl-N'-octadecylidene-1,4-
Phenylenediamine, N-4- (4-hydroxyphenylcarbonylamino) benzylidenedecylamine, 4,
-Hydroxy-4'-octyloxycarbonylaminobenzanilide, 4-hydroxy-4'-tetradecyloxycarbonylaminobenzanilide, 4-hydroxy-4'-octadecylureylenebenzanilide,

3-hydroxy-4'-dodecyloxybenzanilide, N-methyl-4-hydroxy-3'-octadecyloxybenzanilide, 3-hydroxy-
4'-octylbenzanilide, 3-hydroxy-4 '
-Tetradecylbenzanilide, N-methyl-3-hydroxy-4'-octadecylbenzanilide, N-dodecyl-4-hydroxy-3-methylbenzamide, 3-
Methoxy-4-hydroxy-4'-octadecyloxybenzanilide, 3-allyl-4-hydroxy-4'-
Octadecyloxybenzanilide, 3-chloro-4-
Hydroxy-4'-octadecylbenzanilide, 3-
Bromo-4-hydroxy-4'-octadecylbenzanilide, N-octadecyl-4-hydroxy-2,5-
Dimethylbenzamide, N-octadecyl-4-hydroxy-3-ethylbenzamide, 4-hydroxy-4 '
-Octyloxy-3'-methylbenzanilide, 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 ′-
Octadecyl benzanilide,

4- (N-octylsulfonylamino) phenol, 4- (N-dodecylsulfonylamino) phenol, 4- (N-octadecylsulfonylamino) phenol, 4- (N-methyl-N-octadecylsulfonylamino) phenol , 4- (N-3-methylhexylsulfonylamino) phenol, 4'-hydroxy-
4-cyclohexylbenzenesulfonanilide, 4'-
Hydroxy-4-octylbenzenesulfonanilide,
4'-hydroxy-4-dodecylbenzenesulfonanilide, 4'-hydroxy-4-dodecyloxybenzenesulfonanilide, 4'-hydroxy-4-octadecyloxybenzenesulfonanilide, 4'-hydroxy-4- (dodecylthio) benzenesulfone Anilid,
4'-hydroxy-4-hexylcarbonylbenzenesulfonanilide, 4'-hydroxy-4-hexadecylcarbonylbenzenesulfonanilide, 4'-hydroxy-4- (8-heptadecenyl) carbonylbenzenesulfonanilide, 4'-hydroxy-4 -Octyloxycarbonyloxybenzenesulfonanilide, 4'-
Hydroxy-4-dodecyloxycarbonylbenzenesulfonanilide, '-hydroxy-4-octacosyloxycarbonylbenzenesulfonanilide, 4'-hydroxy-4-dodecylcarbonyloxybenzenesulfonanilide, 4'-hydroxy-4-hexylaminobenzene Sulfone anilide, 4'-hydroxy-4-octadecylaminobenzene sulfone anilide,

4'-hydroxy-4-heptadecylcarbonylaminobenzenesulfonanilide, 4'-hydroxy-4-dodecylaminocarbonylbenzenesulfonanilide, 4'-hydroxy-4-dodecylsulfonylbenzenesulfonanilide, 4'-hydroxy- 4-octyloxysulfonylbenzenesulfonanilide,
4'-hydroxy-4-octadecyloxysulfonylbenzenesulfonanilide, 4'-hydroxy-4-dodecylsulfonyloxybenzenesulfonanilide, N
-Octylidene-4- (4-hydroxyphenyl) aminosulfonylaniline, N-dodecylidene-4- (4-
Hydroxyphenyl) aminosulfonylaniline, N-
4- (4-hydroxyphenylaminosulfonyl) benzylidene octadecylamine, 4'-hydroxy-4-
Octyloxycarbonylaminobenzenesulfonanilide, 4'-hydroxy-4-octadecyloxycarbonylaminobenzenesulfonanilide, 4'-hydroxy-4-octadecylureylenebenzenesulfonanilide,

3- (N-dodecylsulfonylamino) phenol, 4- (N-octadecylsulfonamino) catechol, 4- (N-octadecylsulfonamino) resorcinol, 4- (N-octadecylsulfonylamino) pyrogallol, 4'- Hydroxy-3-octyloxybenzenesulfonanilide, 3'-hydroxy-4
-Dodecyloxybenzenesulfonanilide, N-methyl-4'-hydroxy-3-octadecyloxybenzenesulfonanilide, 3'-hydroxy-4-dodecylbenzenesulfonanilide, 3-methyl-4- (N-dodecylsulfonamino) phenol , 4-methyl-3-
(N-tetradecylsulfonamino) 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) hexane, 1- (4-hydroxyphenyldithio) octadecane, 2-heptyl-1- (4-hydroxyphenyldithio) octane, 1- (4-hydroxyphenyldithio)- 9-octadecene, 1- (4-hydroxy-3-
Methylphenyldithio) octadecane, 1- (3-allyl-4-hydroxyphenyldithio) hexadecane, 1
-(4-hydroxy-3-methoxyphenyldithio) octadecane, 1- (2-ethoxy-4-hydroxyphenyldithio) octadecane, 1- (3-chloro-4-hydroxyphenyldithio) octadecane, 1- (2-fluoro -4-hydroxyphenyldithio) octadecane,

4'-hydroxy-4-hexyldiphenyl sulfide, 4'-hydroxy-4-dodecyl diphenyl sulfide, 4'-hydroxy-4-tetradecyl diphenyl sulfide, 4'-hydroxy-4-octadecyl diphenyl sulfide, 4 ' -Hydroxy-4-
Octadecylcarbonylaminodiphenyl sulfide,
4'-hydroxy-4-dodecyloxydiphenyl sulfide, 4'-hydroxy-4-octadecyloxydiphenyl sulfide, 4'-hydroxy-4-dodecylsulfonyldiphenyl sulfide, 4'-hydroxy-
4-Octadecyloxysulfonyldiphenyl sulfide, 4'-hydroxy-4-octadecylsulfonylaminodiphenyl sulfide, 4'-hydroxy-4-tridecylcarbonyldiphenyl sulfide, 4'-hydroxy-4- (N-heptadecylideneamino) diphenyl Sulfide,

4'-hydroxy-3,4-didecyloxydiphenyl sulfide, 4'-hydroxy-3,4-
Dioctadecyloxydiphenyl sulfide, 4'-hydroxy-3-octyl-4- (octylthio) diphenyl sulfide, 4'-hydroxy-3-octadecyl-5-tridecylsulfonyldiphenyl sulfide,
4'-hydroxy-3- (heptadecylthio) -5-pentadecyloxydiphenyl sulfide, 4'-hydroxy-3-heptadecylcarbonylamino-5-dodecyldiphenyl sulfide, 4'-hydroxy-3-octadecylcarbonylamino-5- Octadecyloxydiphenyl sulfide, 4'-hydroxy-3-heptadecyloxysulfonyl-5-tetradecyloxysulfonyl diphenyl sulfide, 4'-hydroxy-3,5
-Bis (N-docosylideneamino) diphenyl sulfide, 4- (15-cyclohexylpentadecyl) -4 '
-Hydroxydiphenyl sulfide, 4'-hydroxy-4- (5-tetradecenyl) diphenyl sulfide,
4'-hydroxy-4- (10-octadecenyloxycarbonyl) diphenyl sulfide, 4'-hydroxy-3'-methyl-4-nonyldiphenyl sulfide,

3'-allyl-4'-hydroxy-4-pentadecyldiphenyl sulfide, 3'-chloro-4 '
-Hydroxy-4-octadecyldiphenyl sulfide, 3'-chloro-4'-hydroxy-4-octadecyl-5-pentadecyloxydiphenyl sulfide,
4'-hydroxy-3'-methyl-4-nonyloxydiphenyl sulfide, 4'-hydroxy-3 '-(1-
Methylethyl) -4-pentacosylsulfonylaminodiphenyl sulfide, 4'-hydroxy-3 '-(2-
Methylpropyl) -4-nonadecyloxysulfonyl diphenyl sulfide, 3'-hydroxy-4-dodecyl diphenyl sulfide, 3'-hydroxy-4-octadecyl diphenyl sulfide, 2 ', 4'-dihydroxy-4-heptadecyl diphenyl sulfide, 3 ',
4'-dihydroxy-4-heptadecyl diphenyl sulfide, 3'-hydroxy-4-dodecyloxycarbonyl diphenyl sulfide,

N- (4-hydroxyphenyl) -N'-
Hexyl urea, N- (4-hydroxyphenyl) -N '
-Octylurea, N- (4-hydroxyphenyl)-
N'-dodecyl urea, N- (4-hydroxyphenyl)
-N'-tetradecyl urea, N- (4-hydroxyphenyl) -N'-hexadecyl urea, N- (4-hydroxyphenyl) -N'-octadecyl urea, N- (4-hydroxyphenyl) -N'-eicosyl Urea, N- (4
-Hydroxyphenyl) -N'-cyclododecylurea,
N- (4-hydroxyphenyl) -N'-docosylurea, N- (4-hydroxyphenyl) -N'-cholesterylurea, N- (4-hydroxyphenyl) -N'-
(2-heptyloctyl) urea, N- (4-hydroxyphenyl) -N '-(2-ethylhexyl) urea, N-
(4-hydroxyphenyl) -N '-(14-cyclohexyltetradecyl) urea, N- (3-methyl-4-hydroxyphenyl) -N'-octadecylurea, N-
(4-Hydroxyphenyl) -N '-(9-octadecenyl) urea, N- (3-allyl-4-hydroxyphenyl) -N'-octadecylurea, N- [3- (1,1-
Dimethylethyl) -4-hydroxyphenyl] -N'-
Octadecyl urea, N- (3,5-dimethyl-4-hydroxyphenyl) -N'-octadecyl urea, N- (2
-Hydroxyphenyl) -N'-octylurea, N-
(3-hydroxyphenyl) -N'-octadecyl urea, N- (3,4-dihydroxyphenyl) -N'-octadecyl urea, N- (3,4,5-trihydroxyphenyl) -N'-tricosyl urea, N- (4-hydroxyphenyl) -N '-(4-tetradecylphenyl) urea, N- (4-hydroxyphenyl) -N'-(4-hexylphenyl) urea, N- (4-hydroxyphenyl)- N '-(3,4-dioctadecylphenyl) urea, N- (4-hydroxyphenyl) -N'-dodecylthiourea, N- (4-hydroxybenzoyl) -N'-
Octadecanoylhydrazine, N- (4-hydroxybenzoyl) -N '-(octadecylcarbamoyl) hydrazine, N- (4-hydroxybenzoyl) -N'-hexadecanoylhydrazine, N- (4-hydroxybenzoyl) -N ′-(Hexadecylcarbamoyl) hydrazine, N- (4-hydroxybenzoyl) -N′-achicosylhydrazine, N- (4-hydroxybenzoyl)
-N '-(eicosylvamoyl) hydrazine, N- (4
-Hydroxyphenyl) -N'-tetradecylthiourea, N- (4-hydroxyphenyl) -N'-hexadecylthiourea, N- (4-hydroxyphenyl) -N '
-Octadecylthiourea, N- (p-hydroxy-β-
Phenethyl) -N'-octadecylurea, 4-hydroxy-N-octadecanoylaminomethylbenzamide,
4-n-octadecyl aminophenol, 4- (1-octadecynyl) phenol, 4- (1,3-octadecadiynyl) phenol and the like can be mentioned.

These reversible developers may be used either individually or in combination of two or more. The amount of the reversible developer based on the dye precursor is 5 to 5000% by weight, preferably It is 50 to 1000% by weight.

The reversible thermosensitive layer in the present invention may contain a pigment, if desired. As the pigment, a white pigment or a colorless pigment, a colored pigment having a color other than the coloring hue or a pigment having a metallic luster is preferably used depending on the application. Specific examples of pigments that can be used include diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, basic magnesium carbonate, titanium oxide, zinc oxide,
Inorganic pigments such as silicon oxide, aluminum hydroxide, calcium silicate, barium sulfate, and calcium sulfate, urea-formalin resin, polystyrene resin, polyethylene resin,
Examples thereof include synthetic or natural organic pigments such as polypropylene resin, benzoguanamine, rice starch, corn starch, wheat starch and other various grain starches. The average particle size of the pigment is preferably 20 μm or less, and particularly preferably 10 μm or less in terms of print quality. If it exceeds 10 microns,
In particular, if the average particle size exceeds 20 μm, the print quality may be deteriorated and the image may be missing.
Further, 0.1 micron or more is preferable in order to improve repeated durability. Those having a thickness of less than 0.1 micron have no particular effect on the repeated durability. However, those having an average particle diameter outside these preferable ranges can also be used in the present invention. The amount of the pigment added is preferably not more than 500% by weight, preferably not more than 300% by weight, and more preferably not more than 150% by weight, based on the dye precursor, for high sensitivity. If the amount of the pigment added exceeds this range, the sensitivity may be lowered, and the image density may be lowered. Further, it is preferably 20% by weight or more, more preferably 30% by weight or more because of sensitivity, print quality, running property and repetitive durability. If the amount of pigment added is less than this range, sensitivity due to pigment addition, print quality,
Some or all of the effects on the running property and the repeated durability may be insufficient. Two or more pigments may be used in combination.

A binder may be added to the reversible heat-sensitive layer for the purpose of improving the strength of the reversible heat-sensitive 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. Water-soluble polymer such as acid ester / methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, alkali salt of ethylene / maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylic acid Ester, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer, ethylene / vinyl acetate copolymer, ethylene / vinyl chloride copolymer, polyvinyl chloride, ethylene Vinylidene chloride copolymers, such as latex such as polyvinylidene chloride and the like but not limited thereto.

Further, as an additive for controlling the color developing sensitivity and the decoloring temperature of the reversible heat-sensitive layer, a heat-fusible substance is further contained in the reversible heat-sensitive layer in addition to the amine compound in the present invention mentioned above. Can be made. The sensitizer used for general thermal paper can also be used. Examples of these compounds include waxes such as N-hydroxymethylstearic acid amide, stearic acid amide, and palmitic acid amide, naphthol derivatives such as 2-benzyloxynaphthalene, and biphenyl derivatives such as p-benzylbiphenyl and 4-allyloxybiphenyl. , 1,2-bis (3-
Polyether compounds such as methylphenoxy) ethane, 2,2'-bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether, diphenyl carbonate, dibenzyl oxalate, bis (p-methylbenzyl oxalate) Examples thereof include carbonic acid such as ester or oxalic acid diester derivative, and it is possible to add two or more kinds in combination.

As the support used in the reversible thermosensitive recording material of the present invention, paper, various non-woven fabrics, woven fabrics, synthetic resin films such as polyethylene terephthalate and polypropylene, paper laminated with synthetic resins such as polyethylene and polypropylene, and synthetic Paper, metal foil such as aluminum, glass, etc., or a composite sheet in which these are combined can be optionally used according to the purpose, but the invention is not limited thereto. These may be opaque, transparent or translucent. In order to make the background look white or other specific color, a white pigment, a colored dye or pigment, or bubbles may be contained in the support or on the surface. In particular, when the hydrophilicity of the support is small and it is difficult to apply the reversible thermosensitive recording layer when aqueous coating is applied to films and the like, hydrophilic treatment of the surface by corona discharge or the like and various polymers are applied to the surface of the support. You may perform easy adhesion processing, such as. In addition to this, a treatment necessary for curl correction, antistatic property, or improvement of running property may be performed.

If necessary, an undercoat layer may be provided between the reversible thermosensitive layer and the support in order to improve the repeating durability and sensitivity of the reversible thermosensitive recording material of the present invention.
In that case, hollow particles or pigments may be used in the undercoat layer.

When hollow particles are used in the undercoat layer, examples of the material thereof include polymers such as polystyrene, styrene-acryl copolymer, polyethylene, polypropylene, melamine-formalin resin and various nylons. There are various known methods for making the inside of particles hollow. The hollow particles may also be included in the reversible thermosensitive layer.

When a pigment is used in the undercoat layer, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, basic magnesium carbonate,
Examples thereof include inorganic pigments such as titanium oxide, zinc oxide, silicon oxide and aluminum hydroxide, and organic pigments such as urea-formalin resin, polystyrene resin, polyethylene resin, polypropylene resin, benzoguanamine resin and various grain starches. Two or more kinds of these pigments or hollow particles may be used in combination.

If desired, a water-soluble polymer or latex can be used in the undercoat layer.
Specific examples thereof include starches, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, polyacrylic acid soda, acrylic acid amide / acrylic acid ester copolymer,
Water-soluble polymer such as acrylic acid amide / acrylic acid ester / methacrylic acid terpolymer, alkali salt of styrene / maleic anhydride copolymer, alkali salt or ammonium salt of ethylene / maleic anhydride copolymer, poly Vinyl acetate, polyurethane, polyacrylic acid ester, styrene / butadiene copolymer, acrylonitrile / butadiene copolymer, methyl acrylate / butadiene copolymer,
Examples of the latex include ethylene / vinyl acetate copolymer, ethylene / vinyl chloride copolymer, polyvinyl chloride, ethylene / vinylidene chloride copolymer, polyvinylidene chloride and the like. These water-soluble polymers or latexes can also be used in the reversible thermosensitive layer according to the present invention. The water-soluble polymer or latex used in each of the undercoat layer and the reversible thermosensitive layer may be the same or different.

When a water-soluble polymer, a latex or a mixture thereof is used in the undercoat layer, the amount used is 200% or less by weight ratio to the solid content (solid content is the total of pigments or hollow particles), and more preferably Is preferably 100% or less from the viewpoint of the effect on repeated durability, and from the viewpoint of adhesive strength, 5% or more, more preferably 10% or more. However, the weight of the hollow particles includes the weight of the liquid when it contains liquid.

When the undercoat layer contains a pigment or hollow particles, the pigment or hollow particles may be made into an emulsion or an aqueous dispersion together with a known dispersant, etc., if necessary, and a water-soluble polymer may be applied to the support. There is a method to smear. The smear amount of the undercoat layer is preferably 0.5 g or more and 20 g or less per square meter (in the case of hollow particles, a value excluding the volatile content inside the particles). If it is less than that, the effect on sensitivity and repeated durability is not sufficient. Beyond that, it may be difficult to consistently obtain a smooth surface.

The layer structure of the reversible thermosensitive recording material of the present invention is as follows:
If necessary, a protective layer may be provided on the reversible thermosensitive layer. The protective layer is formed mainly of a film-forming material such as polyvinyl alcohol, which is listed in the description of the binder of the reversible thermosensitive layer, such as a water-soluble polymer and latex. In that case, a compound having an epoxy group, a hardening agent such as zirconium salt, or a crosslinking agent can be added. In addition, a light and electron beam curable resin or a thermosetting resin may be smeared and cured to form a protective layer. Alternatively, a film may be laminated to form a protective layer. For example, the various films mentioned in the section of description of the support are used for lamination. In any of the above cases, the pigments described below may be blended in order to further improve the writability, the running property or the repeated durability. The average particle size of the pigment used in the protective layer is preferably 0.4 μm or less because the image density is increased. The protective layer may be composed of a plurality of layers of 2 layers or 3 layers or more. The reversible heat-sensitive layer may also be a multi-layer having two or more layers by containing each component one by one or by changing the compounding ratio for each layer. Further, in the reversible heat-sensitive layer and / or on the surface opposite to the surface on which the other layer and / or the reversible heat-sensitive layer is provided, a material capable of electrically, optically and magnetically recording information may be contained. good. Further, a back coat layer may be provided on the surface opposite to the surface on which the reversible heat-sensitive layer is provided for the purpose of blocking prevention, curling prevention, antistatic prevention and the like.

For the protective layer, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, basic magnesium carbonate, titanium oxide, zinc oxide,
Pigments such as silicon oxide, aluminum hydroxide and urea-formalin resin may be contained. These pigments may be simultaneously contained in the reversible heat-sensitive layer, the undercoat layer or the backcoat layer. In addition, zinc stearate, calcium stearate, barium stearate, and other higher fatty acid metal salts, paraffin, oxidized paraffin, polyethylene, oxidized polyethylene, stearic acid amide,
Waxes such as castor wax may also be contained in addition to a dispersant such as sodium dioctylsulfosuccinate, a surfactant, a fluorescent dye or pigment, and a colored dye or pigment.

An organic or inorganic compound capable of absorbing near ultraviolet rays in the protective layer (hereinafter referred to as an ultraviolet absorber)
It is preferable to contain the above in order to improve the light resistance of the image area, the background and the decolored area, and particularly to improve the light resistance of the decolorized area. By providing such a protective layer, the wavelength 3 on the side on which the reversible thermosensitive layer is provided.
When the UV reflectance at 50 nm is less than 50%, the effect on light resistance becomes remarkable.

The UV absorber used in the protective layer may be any UV absorber having an absorption capable of reducing the UV reflectance at a wavelength of 350 nm as much as necessary. Especially 400 nm or less 290
An ultraviolet absorber capable of having an ultraviolet reflectance of less than 50% in the protective layer in the entire near-ultraviolet region of nm or more is preferable because it further improves the light resistance of the decolored portion. . In addition, wavelengths of 400 nm or more and 700 nm or more except for the purpose of coloring.
Those which do not substantially absorb visible light up to the above are preferable.

Examples of such an ultraviolet absorber include various known ultraviolet absorbers. In addition, various dye / pigment intermediates, medical and agricultural chemicals and their intermediates, organosilicon compounds known as charge transfer substances, carbon compounds such as C ₆₀ (so-called buckminsterfullerene), etc., which absorb at around 350 nm are also available. It is preferably used as an ultraviolet absorber used in the invention. In the present invention, the range of the ultraviolet absorber includes organic polymers and salts of organic compounds having near-ultraviolet absorption ability.

It is known that the maximum absorption wavelength varies depending on the ultraviolet absorber, but when used in the present invention, absorption at 350 nm is sufficient. Next, specific examples of the ultraviolet absorber will be listed by system. However, the ultraviolet absorber that may be used in the present invention is not limited to the following specific examples.

(1) Benzotriazole type UV absorber 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3'-t-
Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di- t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-di -T-pentylphenyl) benzotriazole, 2- [2'-hydroxy-3 '-(3 ",
4 ", 5", 6 "-tetrahydrophthalimidomethyl)
-5'-methylphenyl] benzotriazole, 2-
[2′-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2
-(2'-Hydroxy-3'-n-dodecyl-5'-methylphenyl) benzotriazole.

(2) Benzophenone type UV absorber 2-hydroxybenzophenone, 2-hydroxy-4-
Methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-4-
n-octyloxybenzophenone, 2-hydroxy-
4-n-dodecyloxybenzophenone, 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-
4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone and the like can be mentioned.

(3) Other UV Absorbers Salicylic acid UV absorbers such as phenyl salicylate, pt-butylphenyl salicylate, p-octylphenyl salicylate. 2-ethylhexyl 2-cyano-
Cyanoacrylate UV absorbers such as 3,3'-diphenyl acrylate and ethyl 2-cyano-3,3'-diphenyl acrylate.

As a UV absorber, a near UV absorbing inorganic compound can be used in the protective layer. Specific examples of the inorganic ultraviolet absorber include zinc oxide, zinc sulfide, cerium oxide, titanium dioxide and the like. There are two types of titanium dioxide, rutile type and anatase type, and both are preferably used. The surface of particles of these inorganic compounds may be subjected to surface treatment such as silane treatment or alkylation.

The means for incorporating the ultraviolet absorber into the protective layer will be described below. Materials other than the ultraviolet absorber are contained in the protective layer as necessary, and therefore the description of the same content method will be given together. In the case of an inorganic compound, the method of adding it to the protective layer is the same as in the case of other pigments described later. However, if it is soluble in a solvent, it is more effective if it is encapsulated in microcapsules as described below, as in the case of an organic ultraviolet absorber.

When the method of incorporating an ultraviolet absorber into the protective layer is classified from the smearing method, water or an organic solvent is used as a medium,
Alternatively, it can be divided into a wet method in which the ultraviolet absorbent itself is applied in a liquid state and smearing, and a dry method in which powder is applied without a solvent. In many cases, the wet method is easier to manufacture. Next, preferable addition methods are listed. 1. A method of dispersing and smearing microcapsules containing an oil solution or an oil dispersion of an ultraviolet absorber in water. 2. A method in which an ultraviolet absorber is dispersed, emulsified or dissolved in water or an organic solvent and smeared. 3. A method in which an ultraviolet absorber which itself becomes a liquid or a liquid when heated is heated to a liquefaction temperature or higher as necessary and smeared. In any of the above methods, the aggregated state of the ultraviolet absorber after smearing is divided into a homogeneous system and a heterogeneous system, and the homogeneous system is more effective in terms of image density and light resistance of the erased part. .
Great compatibility with UV absorbers to obtain a homogeneous system,
Alternatively, it is also preferable to use a soluble material such as a binder or an additive together with the ultraviolet absorber. Further, it is preferable that the ultraviolet absorber is a uniform liquid or solution at the time of smearing because a uniform system can be easily obtained. As one of the modes, when a microcapsule system is used, the microcapsule itself is a heterogeneous system (dispersion system), but the continuous system of the microcapsules produces the same effect as the homogeneous system.
In addition to this, a non-homogeneous system may obtain an effect close to that of a homogeneous system. One of them is the case where the average particle diameter of the ultraviolet absorber is reduced to 1 micron or less. Further, if the melting point of the ultraviolet absorber is below the temperature for developing or erasing the image, preferably below 120 ° C., especially below 100 ° C., the ultraviolet absorber melts at the time of printing or erasing, resulting in a heterogeneous system. Also has an effect close to that of a homogeneous system. The preferred addition method will be described in more detail below.

The microcapsule system may be added by dissolving or dispersing an ultraviolet absorber in a solvent and incorporating it into a microcapsule, and dispersing the microcapsule together with a water-soluble polymer, latex or a mixture thereof. The method of coating on the support is preferable from the viewpoint of repeated durability. As a method for producing the microcapsules, known techniques in the conventional applications of the microcapsules such as heat-sensitive recording and pressure-sensitive copying can be applied.

Examples of the method for producing microcapsules include an interfacial polymerization method, an in-situ method, an in-liquid curing method, a spray drying method and the like. In addition to this, known methods for producing microcapsules such as a coacervation method and a method using yeast (Japanese Patent Laid-Open No. 63-88033) can be used. Of these, the above-mentioned ultraviolet absorber is dissolved or dispersed in an organic solvent as necessary, and the oily solution is prepared as an emulsion in an aqueous medium, and a film made of a polymer compound is formed around the emulsion. Is preferred. Preparation becomes easier by using an emulsifier. The average particle size (volume average particle size) of the microcapsules is preferably 5 microns or less, and particularly preferably 2 microns or less from the viewpoint of repeated durability. The oily liquid may be solidified at room temperature or the solute may be partially or wholly solidified as long as it is liquid under the conditions for producing microcapsules. In addition to this, a part of the organic solvent may be volatilized to form a hollow inside the microcapsule. The solute may contain components added to each layer and components necessary for film formation described below, as necessary, in addition to the ultraviolet absorber.

As the polymer compound (film material) which forms the film of the microcapsule, an aminoplast resin such as melamine resin-formalin resin, urea-formalin resin, benzoguanamine-formalin resin (obtained by a polymerization reaction of an amino compound and formaldehyde). Resin), polyurea resin, polyurethane resin, polyamide resin, polyester resin, polycarbonate resin, aminoaldehyde resin, polystyrene resin, styrene-acrylate copolymer resin, gelatin, polyvinyl alcohol and the like. Among these, when a nitrogen-containing resin such as an aminoplast resin or a polyurea resin is used, preferable results are obtained in terms of repeated durability and image density. A known method is used for producing and dispersing the microcapsules.

An organic solvent is used if necessary for preparing an oily liquid. The lower limit of the weight% concentration of the ultraviolet absorbent in the organic solvent is determined by the ultraviolet absorbing ability of the microcapsules to be produced, and finally by the ultraviolet reflectance of the protective layer. There is no particular limitation on the selection of the organic solvent as long as it is a layer that separates from water, and the organic solvent used for microcapsules for pressure-sensitive copying sheets and the like are preferably used. In addition to the above, a volatile organic solvent may be used together for the purpose of adjusting the viscosity and specific gravity of the oily liquid when producing the microcapsules. When the ultraviolet absorbent itself becomes an oily liquid, there is a case where the organic solvent may not be used. The weight ratio of the oily liquid to the total weight of the microcapsules (excluding the amount that volatilizes by the time of producing the reversible thermosensitive recording material) is preferably 95% or less. If it exceeds this range, the film becomes thin, and the durability against repeated use may decrease.

Specific examples of the organic solvent include animal and vegetable oils such as cottonseed oil, paraffin, naphthenic oil, chlorinated paraffin,
Mineral oils such as kerosene and gas oil, tricresyl phosphate, octyldiphenyl phosphate and other phosphate esters, diethyl phthalate, dibutyl phthalate, diethylhexyl phthalate and other phthalates, diethylene glycol dibenzoate, butyl oleate , Dioctyl adipate,
Carboxylic acid esters such as diethylhexyl adipate, various fatty acid amides such as N, N-dimethyllauramide, N, N-dimethylstearamide, alkylated naphthalenes such as monoisopropylnaphthalene and diisopropylnaphthalene, 1-methyl- Alkylated benzenes such as 1-phenyl-1-xylylmethane, 1-phenyl-1-tolylmethane, alkylated biphenyls such as isopropyl biphenyl, ethers such as o-phenylphenol glycidyl ether, acryl such as trimethylolpropane triacrylate Acid esters, ketones such as diisobutyl ketone and methylhexyl ketone, alkylene carbonates such as ethylene carbonate and propylene carbonate, polydimethylsiloxane, polymethylphenylsiloxane Silicone oils such as octamethylcyclotetrasiloxane, and the like. These two
You may use together 1 or more types.

Besides this, a volatile solvent may be used in combination. As the volatile solvent, ethyl acetate, esters such as butyl acetate, toluene, aromatic hydrocarbons such as xylene, butane, hexane, pentane, heptane, octane, saturated hydrocarbons such as cyclohexane, methylene chloride, chloroform, Examples thereof include halogen-containing organic solvents such as carbon tetrachloride, ethers such as diisopropyl ether and diethyl ether, and ketones such as methyl ethyl ketone, methyl isopropyl ketone and methyl isobutyl ketone.

Various anions, nonions, cations, or amphoteric water-soluble materials are used as a dispersant and an emulsifier that are optionally used in the preparation of microcapsules.
The dispersant and the emulsifier are preferably added as an aqueous solution (concentration of 0.5 to 20.0% by weight).

The anionic dispersant has, for example, a group such as a carboxy group or a sulfo group, which is an anionic residue obtained by neutralizing a part or all of acidic residues, or a group which can be produced during microcapsule production. There are things. Examples of natural materials include gum arabic, carrageenan, sodium alginate, ammonium alginate, pectic acid, tragacanth gum, almond gum, agar and the like. Examples of the semi-synthetic material obtained by chemically modifying a natural material include carboxymethyl cellulose, sulfated cellulose, sulfated methyl cellulose, carboxymethylated starch, phosphorylated starch, and lignin sulfonic acid. As a synthetic material, a polymer or copolymer containing maleic anhydride as at least one component of a monomer and a hydrolyzed product thereof, a polymer or copolymer of unsaturated fatty acids such as acrylic acid, methacrylic acid or crotonic acid Polymers, copolymers of sulfonic acids having a carbon-carbon unsaturated bond such as polymer, vinylbenzene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, etc., partial amidation of these various polymers or copolymers, or Examples thereof include partially esterified products, carboxy-modified polyvinyl alcohol, sulfonic acid-modified polyvinyl alcohol, phosphoric acid-modified polyvinyl alcohol, and other modified polyvinyl alcohols.

Examples of the nonionic dispersants include hydroxyethyl cellulose, methyl cellulose, pullulan, solubilized starch, oxidized starch, polyvinyl alcohol and the like. Examples of the cationic dispersant include cation-modified polyvinyl alcohol and the like. Examples of the amphoteric dispersant include gelatin and the like. Various anions, nonions, cations, or amphoteric water-soluble polymers are used as a dispersant, which is optionally used during preparation of the microcapsules or during emulsion dispersion of the oily liquid.

Next, a method of coloring and erasing the reversible thermosensitive recording material of the present invention will be described. In order to develop a color, rapid cooling may occur after heating, and for example, heating with a thermal head, laser light or the like is possible. Alternatively, even by heating with a heat roll or a heat stamp or the like, color can be developed if the speed of passing the sheet is increased or if rapid cooling with a cooling roll or cold air can be performed. Also, if heated and cooled slowly, the color disappears, and for example, it is slowly heated after being heated using radiant heat from a thermal head, a heat roll, a heat stamp, high frequency heating, hot air, an electric heater, or a light source such as a tungsten lamp or a halogen lamp. It can be done by cooling.

Next, a specific method for producing the reversible thermosensitive recording material of the present invention will be described, but the present invention is not limited thereto. As a specific example of the method for producing the reversible thermosensitive recording material of the present invention, a reversible material containing a dye precursor, a reversible developer and the amine compound according to the present invention as a main component on a support and optionally a pigment A method of forming a reversible heat-sensitive layer by smearing and drying the heat-sensitive coating liquid is mentioned. The layer structure has been described above such that an undercoat layer is provided between the support and the reversible heat-sensitive layer, if necessary. The method of smearing each layer is not particularly limited and can be formed by a conventional method. For example, an air knife coater,
Smearing device such as blade coater, bar coater, curtain coater, planographic printing, letterpress printing, intaglio printing, flexo, gravure,
It is possible to use various types of printers such as screens and hot melts. In the hot melt method, each component is mixed and heated without using a solvent or a dispersion medium to melt a fusible component and apply it while hot. In this case, if there is a pigment component in the reversible heat-sensitive layer or the like, it is dispersed in the other heat-fusible component during heating.

As a method for preparing a reversible heat-sensitive coating liquid containing a dye precursor, a reversible developer and a compound according to the present invention as main components and optionally a pigment, each compound is dissolved or dispersed alone in a solvent. Method of dispersing in a medium and then mixing, method of mixing each compound and then dissolving in a solvent or dispersing in a solvent, heating each compound to homogenize and homogenize and then cool, dissolve in a solvent or dispersion medium The method of dispersion may be mentioned, but it is not specified. At the time of dispersion, a dispersant may be used if necessary. When water is the dispersion medium, examples of the dispersant include water-soluble polymers such as polyvinyl alcohol and various surfactants. A water-soluble organic solvent such as ethanol may be mixed when the aqueous dispersion is performed. In addition to this, when an organic solvent represented by hydrocarbons is a dispersion medium, lecithin, phosphoric acid esters or the like may be used as a dispersant.

[0091]

The present invention will be described in more detail with reference to the following examples. The parts and percentages in the examples are on a weight basis.

Example 1 (A) Preparation of reversible heat-sensitive coating liquid 10 parts of hexamethylenetetramine was dissolved in 40 parts of a 2.5% polyvinyl alcohol aqueous solution to obtain an aqueous solution. 3-
40 parts of diethylamino-6-methyl-7-anilinofluorane were pulverized with a ball mill together with 90 parts of a 2.5% polyvinyl alcohol aqueous solution to obtain a dye precursor dispersion liquid. Then, 150 parts of N- (4-hydroxyphenyl) -N'-n-eicosylurea was pulverized together with 600 parts of 2.5% polyvinyl alcohol aqueous solution by a ball mill to obtain a reversible developer dispersion. Further, 20 parts of basic magnesium carbonate having a particle size of 5.1 μm was dispersed together with 50 parts of a 4.0% polyvinyl alcohol aqueous solution with a homogenizer to obtain a pigment dispersion liquid. After mixing the above four kinds of dispersions and solutions, 220 parts of 10% polyvinyl alcohol aqueous solution and 100 parts of water were added and mixed well to prepare a reversible heat-sensitive coating liquid.

(B) Preparation of reversible heat-sensitive recording material The reversible heat-sensitive layer coating solution prepared in (A) was applied to foamed polyethylene terephthalate having a thickness of 188 μm so as to give a solid content of 3.6 g / m ² and dried. After that, it was processed with a super calendar. Further, a 5% aqueous solution of polyvinyl alcohol was smeared and dried to give a solid content of 1.5 g / m ² to obtain a reversible thermosensitive recording material.

Example 2 Example 1 was repeated except that the hexamethylenetetramine aqueous solution used in Example 1 was replaced with a dispersion in which benzoguanamine was dispersed in a ball mill together with 40 parts of a 2.5% polyvinyl alcohol aqueous solution. Similarly, a reversible thermosensitive recording material was obtained.

Example 3 Example 1 was repeated, except that the aqueous solution of hexamethylenetetramine used in Example 1 was replaced with a dispersion in which adenine was dispersed in a ball mill together with 40 parts of a 2.5% polyvinyl alcohol aqueous solution. Similarly, a reversible thermosensitive recording material was obtained.

Comparative Example 1 A reversible thermosensitive recording material was obtained in the same manner as in Example 1, except that the aqueous solution of hexamethylenetetramine used in Example 1 was omitted.

Comparative Example 2 A reversible thermosensitive recording material was obtained in the same manner as in Example 1 except that the aqueous glycerin solution was used instead of the aqueous hexamethylenetetramine solution used in Example 1.

Printing, Decoloring and Durability Test The reversible thermosensitive recording materials obtained in Examples 1 to 3 and Comparative Examples 1 and 2 were printed with Kyocera print head KJT-256-8MGF.
Okura Electric Thermal Printing Tester TH-P with 1
Printing was performed using an MD with an applied pulse of 1.1 milliseconds for an applied voltage of 26 V, and the image density was measured. The image was erased by heating with a hot roll at 110 ° C. to 120 ° C., and the optical density of the decolored portion was measured. This printing and erasing were repeated 100 times, and the density of the black image obtained at the 100th time was measured using a densitometer Macbeth RD918. The image densities of Examples 1 to 3 and Comparative Examples 1 and 2 were in the range of 1.1 to 1.2 in the first printing, and the density of the decolored portion was 0.1 or less. The image density of the 100th printing was maintained at 1.0 or higher in all of Examples 1 to 3 and Comparative Examples 1 and 2.

Image storability test The image obtained by the above printing test (first time) was allowed to stand in a constant temperature bath at 40 ° C. for 14 hours, and the image density was measured. Examples 1-3
The image densities were 0.96, 0.91, and 1.00, respectively, and the black images were still good, but Comparative Examples 1 and 2
In each case, the decrease was 0.75 and 0.19, respectively.

[0100]

INDUSTRIAL APPLICABILITY A reversible thermosensitive recording material containing a colorless or light-colored dye precursor and a reversible developer which causes the dye precursor to undergo reversible color tone change due to difference in cooling rate after heating. By including an amine compound in the reversible thermosensitive layer, images can be formed and erased with good contrast, and a stable image is maintained over time not only in the environment of daily life but also under heating conditions. It was possible to obtain a reversible thermosensitive recording material which was excellent in sensitivity and repeatability.

Claims (1)

[Claims] 1. A main component is a colorless or light-colored dye precursor on a support, and a reversible developer that causes a reversible color change in the dye precursor due to a difference in cooling rate after heating. A reversible heat-sensitive recording material provided with a reversible heat-sensitive layer, wherein the reversible heat-sensitive layer contains an amine compound.