JPH06340172A - Reversible heat-sensitive recording material - Google Patents

Abstract

PURPOSE:To provide a reversible heat-sensivie recording material which is free from deterioration of a recording layer even if a repetition of formation and removal of an image is performed and enables the formation and erasure of the image in a favorable and fixed contrast. CONSTITUTION:A reversible heat-sensitive recording layer containing mainly a normally-colorless or light-colored electron-donating dye precursor and a reversible developer which causes the d3 precursor to generate a reversible color tone change on the dye precursor through a difference in cooling rates after cooling and a heat-resistant and wear-resistant transparent sheet are laminated in order. Hereby, a reversible heat-sensitive recording material which can form and erase an image in a favorable contrast and has little deterioration on quality of the image even if the formation and erasure of the image are performed repeatedly can be obtained.

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 heating.

[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 forming portion and the image non-forming portion 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 thermosensitive recording medium 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 compound having an acidic group for coloring a leuco dye and a basic group for decoloring a leuco dye that has formed a color, and a coloring action by an acidic group or a decoloring action by a basic group 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.

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. do not do.

On the other hand, the inventors of the present invention have generally accepted an electron-accepting dye precursor, which is colorless or light-colored, and an electron-accepting dye precursor which causes a reversible color tone change due to the difference in cooling rate after heating. Of reversible thermosensitive recording materials containing a photosensitive compound are disclosed in Japanese Patent Application No. 4-158098 and Japanese Patent Application No. 4-2477.
No. 88, Japanese Patent Application No. 4-247789, Japanese Patent Application No. 4-282
954, Japanese Patent Application No. 4-282955, Japanese Patent Application No. 4-28
No. 2956, Japanese Patent Application No. 4-347032, etc.
This reversible thermosensitive recording material has a good image contrast, is capable of forming and erasing an image, and is capable of holding a stable image with time in an environment of daily life.

Writing and erasing of information on the reversible thermosensitive recording material is usually carried out by heating with a thermal head or the like. When writing and erasing are repeated, the reversible thermosensitive recording layer is physically damaged, and the composition in the recording layer adheres to the thermal head, causing deterioration of the recording layer. In order to prevent this, a protective layer is usually formed on the recording layer by coating and used.

[0011]

However, the protective layer formed by the above-mentioned coating method does not have sufficient heat resistance and abrasion resistance, and the protective layer deteriorates when image formation and erasure are repeated by heating. However, there has been a problem that the amount of heat applied to the reversible thermosensitive recording layer increases, and the density of the color-developed portion increases as image formation / erasing is repeated. Further, when image formation / erasure is repeated, there is a problem that the protective layer is damaged and loses its function, the reversible thermosensitive recording layer is damaged, the color density is lowered, and the quality of the recorded image is deteriorated. In addition, the protective layer formed by the coating method may contain an uncured component, a component that is melted by heating for forming / erasing an image, and the like. By repeating the above, there is a problem that the reversible thermosensitive recording layer is mixed with the reversible thermosensitive recording layer to deteriorate the coloring density, the decoloring density and the stability of the formed image.

An object of the present invention is to prevent the deterioration of the reversible thermosensitive recording layer even when writing and erasing are repeated, and to form and erase an image with good and constant contrast.
An object is to provide a reversible thermosensitive recording material having good image stability.

[0013]

As a result of research for solving the above-mentioned problems, as a result, a colorless or light-colored electron-donating dye precursor is usually provided on a support, and the dye precursor is different due to a difference in cooling rate after heating. This problem has been solved by a reversible thermosensitive recording material comprising a reversible thermosensitive recording layer mainly containing a reversible color developer that causes a reversible color change and a heat-resistant and abrasion-resistant transparent sheet are sequentially laminated. .

The heat-resistant and abrasion-resistant transparent sheet used in the present invention includes polyethylene terephthalate, polybutylene terephthalate, polysulfone, polyethylene naphthalate, polyphenylene sulfide, polyphenylene ether, polyarylate, polyetherimide, polyetheretherketone. Examples of the film include, but are not limited to, films such as polyamide, polyimide, polyamideimide, and fluororesin.

These may be used by adhering one kind or two or more kinds of sheets, and the kind and combination of the sheets can be appropriately selected depending on the application.

The thickness of the heat-resistant and abrasion-resistant transparent sheet used in the present invention is appropriately selected depending on the application. When the transparent sheet is thick, a large amount of heat energy is required to obtain a color image, but the durability against repeated image formation and erasing is improved. On the contrary, if the transparent sheet is thin, a colored image can be obtained with a smaller amount of energy, but the durability against repeated image formation and erasing is deteriorated. The thickness of the transparent sheet is preferably 0.5 to 50 μm, and 1
Those having a thickness of up to 20 μm are particularly preferable.

When a means for heating the reversible thermosensitive recording layer by heating by contacting the recording material, such as a thermal head, is used for the purpose of improving heat resistance and wear resistance, It is preferable to provide a heat-resistant / wear-resistant layer having heat resistance and wear resistance on the surface of the transparent and wear-resistant transparent sheet that comes into contact with the thermal head or the like. The heat-resistant / wear-resistant layer is composed of a composition containing a heat-resistant resin as a main component, and may contain an additive such as a lubricant if necessary. The heat-resistant / wear-resistant layer can be formed by a method such as a coating method, and the thickness of the heat-resistant / wear-resistant layer is preferably 0.1 to 5 μm, and preferably 0.5 to 2.5 μm. Particularly preferred.

First, the reversible thermosensitive recording layer used in the present invention causes a reversible change in color tone of the dye precursor, which is usually colorless or light-colored, and the cooling rate after heating. Mainly contains a reversible color developer,
By controlling the thermal energy, the state of color development and the state of decolorization are reversibly repeated.

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 usually colorless or light-colored electron-donating dye precursor due to the difference in cooling rate after heating. The present inventors have proposed Japanese Patent Application No. 4-158098 from the viewpoint of image contrast, repeated durability, etc.
Japanese Patent Application No. 4-247788 and Japanese Patent Application No. 4-24778.
No. 9, Japanese Patent Application No. 4-282954, Japanese Patent Application No. 4-2829
55, Japanese Patent Application No. 4-282956, Japanese Patent Application No. 4-347.
No. 032 and the like, which is used in a reversible thermosensitive recording material, an aliphatic hydrocarbon having 6 or more carbon atoms which causes a reversible color tone change in a usually colorless or light-colored electron-donating dye precursor due to a difference in cooling rate after heating. An electron-accepting compound having a group is preferable, and a phenol compound having at least one aliphatic hydrocarbon group having 6 or more carbon atoms is particularly preferably used. Specific examples include the following, 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-hydroxybenzamide, N-cyclohexylmethyl-4-hydroxybenzamide, N-octyl-4-hydroxybenzamide, N-dodecyl-4-hydroxybenzamide, N
-Octadecyl-4-hydroxybenzamide, N-methyl-N-octadecyl-4-hydroxybenzamide, N-octacosyl-4-hydroxybenzamide,
N- (3-methylhexyl) -4-hydroxybenzamide, 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,

N-dodecyl-3-hydroxybenzamide, N-octadecyl-3,4-dihydroxybenzamide, N-octadecyl-2,3,4-trihydroxybenzamide, 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, 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'-octadecylbenzanilide and the like can be mentioned.

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, 4'-hydroxy-4-octacosyloxycarbonylbenzenesulfonanilide, 4'-hydroxy-4-dodecylcarbonyloxybenzenesulfonanilide, 4'-hydroxy-4-hexylamino Benzenesulfonanilide, 4'-hydroxy-4-octadecylaminobenzenesulfonanilide,

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-hydroxyphenylthio) hexane, 1- (4-hydroxyphenylthio) dodecane,
1- (4-hydroxyphenylthio) octadecane, 1
-(3-hydroxyphenylthio) octadecane, 1-
(4-hydroxyphenylthio) docosane, 1- (4-
Hydroxyphenylthio) tetracosane, 2-heptyl-1- (4-hydroxyphenylthio) octane, 1-
(4-hydroxyphenylthio) -9-octadecene,
1- (4-hydroxy-3-methylphenylthio) octadecane, 1- (3-allyl-4-hydroxyphenylthio) hexadecane, 1- [4-hydroxy-3-
(1,1-Dimethylethyl) phenylthio] tetracosane, 1- (4-hydroxy-3-methoxyphenylthio) octadecane, 1- (2-ethoxy-4-hydroxyphenylthio) octadecane, 1- (3-chloro-4)
-Hydroxyphenylthio) octadecane, 1- (2-
Fluoro-4-hydroxyphenylthio) octadecane, 1- (2-hydroxyphenylthio) octane, 1
-(3-hydroxyphenylthio) octadecane, 1-
(3,4-dihydroxyphenylthio) octadecane,
1- (3,4-dihydroxyphenylthio) icosane,

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, and the like.

N- (4-hydroxyphenyl) -N'-
Hexyl urea, N- (4-hydroxyphenyl) -N '
-Octylurea, N- (4-hydroxyphenyl)-
N'-dodecyl urea, N- (4-hydroxyphenyl)
-N'-octadecyl urea, N- (4-hydroxyphenyl) -N'-docosyl urea, N- (4-hydroxyphenyl) -N '-(2-heptyloctyl) 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-hydroxybenzylidene) dodecylamine, N- (4-hydroxybenzylidene) octadecylamine, N- (4-hydroxybenzylidene)
-4'-hexylaniline, N- (4-hydroxybenzylidene) -4'-octylaniline, N- (4-hydroxybenzylidene) -4'-tetradecylaniline,
N- (4-hydroxybenzylidene) -4'-dodecyloxyaniline, N- (4-hydroxybenzylidene)
-4'-octadecyloxyaniline, N- (4-hydroxybenzylidene) -4 '-(octylthio) aniline, N- (4-hydroxybenzylidene) -4'-hexadecylcarbonylaniline, N- (4-hydroxybenzylidene) -4'-octyloxycarbonylaniline, N- (4-hydroxybenzylidene) -4'-octadecyloxycarbonylaniline, N- (4-hydroxybenzylidene) -4'-dodecylcarbonyloxyaniline, N- (4-hydroxybenzylidene) ) -4 '
-Tetradecylcarbonyloxyaniline, N- (4-
Hydroxybenzylidene) -4'-octadecyloxycarbonyloxyaniline, N- (4-hydroxybenzylidene) -4'-cyclohexylaminoaniline, N
-(4-hydroxybenzylidene) -4'-dodecylaminoaniline,

N- (4-hydroxybenzylidene)-
4'-heptadecylcarbonylaminoaniline, N-
(4-hydroxybenzylidene) -4'-dodecylaminocarbonylaniline, N- (4-hydroxybenzylidene) -4'-octadecylaminocarbonylaniline, N- (4-hydroxybenzylidene) -4'-dodecylsulfinylaniline, N- (4-hydroxybenzylidene) -4'-dodecylsulfonylaniline, N
-(4-hydroxybenzylidene) -4'-octadecylsulfonylaniline, N- (4-hydroxybenzylidene) -4'-octyloxysulfonylaniline, N- (4-hydroxybenzylidene) -4'-octacosyloxysulfonylaniline , N- (4-hydroxybenzylidene) -4 '-(3-methylhexyl)
Oxysulfonylaniline, N- (4-hydroxybenzylidene) -4'-dodecylsulfonyloxyaniline, N- (4-hydroxybenzylidene) -4'-
(Octylthiocarbonyl) aniline, N- (4-hydroxybenzylidene) -4'-octyloxycarbonylaminoaniline, N- (4-hydroxybenzylidene) -4'-octadecyloxycarbonylaminoaniline, N- (4-hydroxybenzylidene) ) -4'-Octadecylureyleneaniline,

N- (3-hydroxybenzylidene) dodecylamine, N- (3,4-dihydroxybenzylidene) octadecylamine, N- (2,4-dihydroxybenzylidene) octadecylamine, N- (3,4,5)
-Trihydroxybenzylidene) octadecylamine,
N- (4-hydroxy-3-methylbenzylidene) dodecylamine, N- (3-hydroxy-4-methylbenzylidene) dodecylamine, N- (4-hydroxy-α-
Methylbenzylidene) -4'-dodecylaniline, N-
(4-hydroxy-α-methylbenzylidene) -4′-
Octadecylaniline, N- (4-hydroxy-3-methoxybenzylidene) dodecylamine,

N-octylidene-4-hydroxyaniline, N-tetradecylidene-4-hydroxyaniline,
N-octadecylidene-4-hydroxyaniline, N-
(4-dodecyl) benzylidene-4'-hydroxyaniline, N- (4-octyloxy) benzylidene-4 '
-Hydroxyaniline, N- (4-octadecyloxy) benzylidene-4'-hydroxyaniline, N-
(4-Octadecylthio) benzylidene-4'-hydroxyaniline, N- (4-undecylcarbonyl) benzylidene-4'-hydroxyaniline, N- (4-tridecylcarbonyl) benzylidene-4'-hydroxyaniline, N- (4-Heptadecylcarbonyl) benzylidene-4'-hydroxyaniline, N- {4- (8-heptadecenylylcarbonyl) benzylidene} -4'-hydroxyaniline, N- (4-dodecyloxycarbonyl) benzylidene-4 ′ -Hydroxyaniline, N-
(4-Octadecyloxycarbonyl) benzylidene-
4'-hydroxyaniline, N- (4-octylcarbonyloxy) benzylidene-4'-hydroxyaniline, N- (4-octadecylcarbonyloxy) benzylidene-4'-hydroxyaniline, N- (4-hexylamino) benzylidene- 4'-hydroxyaniline,
N- (4-octadecylamino) benzylidene-4'-
Hydroxyaniline,

N- (4-octadecylcarbonylamino) benzylidene-4'-hydroxyaniline, N-
(4-dodecylaminocarbonyl) benzylidene-4 '
-Hydroxyaniline, N- (4-octadecylaminocarbonyl) benzylidene-4'-hydroxyaniline, N- (4-dodecylsulfinyl) benzylidene-
4'-hydroxyaniline, N- (4-octylsulfonyl) benzylidene-4'-hydroxyaniline, N
-(4-dodecylsulfonyl) benzylidene-4'-
Hydroxyaniline, N- (4-octylsulfonyloxy) benzylidene-4'-hydroxyaniline, N
-(4-dodecylsulfonyloxy) benzylidene-
4′-hydroxyaniline, N- (4-dodecyloxysulfonyl) benzylidene-4′-hydroxyaniline, N- (4-octadecyloxysulfonyl) benzylidene-4′-hydroxyaniline, N- (4-octylthiocarbonyl) benzylidene -4'-hydroxyaniline, N- (4-dodecyloxycarbonylamino) benzylidene-4'-hydroxyaniline, N-
(4-octadecyloxycarbonylamino) benzylidene-4'-hydroxyaniline, N- (4-octadecylureylene) benzylidene-4'-hydroxyaniline,

N-dodecylidene-3-hydroxyaniline, N-octadecylidene-3,4-dihydroxyaniline, N-octadecylidene-3,4,5-trihydroxyaniline, N- (4-octadecyl) benzylidene-3 ', 4 '-Dihydroxyaniline, N- (4-tetradecyl) benzylidene-3'-methyl-4'-hydroxyaniline, N- (4-tetradecyl-3,5-dimethyl) benzylidene-4'-hydroxyaniline, N-
(4-tetradecyl) benzylidene-2'-chloro-
4'-hydroxyaniline, N- (4-octadecyl-
3-Methyl) benzylidene-3 ′, 4′-dihydroxyaniline 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.

The usually colorless to light-colored electron-donating dye precursor used in the present invention is typified by those generally used for pressure-sensitive recording paper and heat-sensitive recording paper, 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-N-tolyl) amino-6-methyl-7-anilinofluorane, 3-piperidino-6-methyl- 7-anilinofluoran, 3-
(N-ethyl-N-tolyl) amino-6-methyl-7-
Phenethylfluorane, 3-diethylamino-7- (4
-Nitroanilino) fluorane, 3-dibutylamino-
6-methyl-7-anilinofluorane, 3- (N-methyl-N-propyl) amino-6-methyl-7-anilinofluorane, 3- (N-ethyl-N-isoamyl) amino-6- Methyl-7-anilinofluorane, 3- (N-
Methyl-N-cyclohexyl) amino-6-methyl-7
-Anilinofluorane, 3- (N-ethyl-N-tetrahydrofuryl) amino-6-methyl-7-anilinofluorane, etc.

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

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

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

The reversible thermosensitive recording material of the present invention undergoes reversible color tone change, that is, color development or decolorization depending on the difference in cooling rate after heating. In order to develop color, rapid cooling may occur after heating, for example, after heating by a suitable method,
Rapid cooling can be performed by a method of pressing a low temperature metal block or the like for cooling, a method of heating for a very short time with a thermal head, laser light or the like. Further, the color is erased by slowly cooling after heating. For example, thermal head, laser light, heat roll, heat stamp, high frequency heating,
It is possible to perform slow cooling by heating for a relatively long time and leaving to cool with radiant heat from a hot air, an electric heater and a light source such as a tungsten lamp and a halogen lamp.

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 colorless or light-colored electron-donating dye precursor and a reversible developer are usually used as main components, and these are coated on a support. To form a reversible thermosensitive recording layer, and to bond and integrate a heat-resistant and abrasion-resistant transparent film on the surface of the reversible thermosensitive recording layer, usually a colorless or pale color electron-donating dye precursor and a reversible developer. And the like, and a method of coating these on a transparent film to form a reversible thermosensitive recording layer, and adhering and integrating a support on the surface of the reversible thermosensitive recording layer.

As a method for adhering and integrating a heat-resistant and abrasion-resistant transparent film on the surface of a reversible thermosensitive recording layer formed on a support, the reversible thermosensitive recording is carried out by superposing both of them and applying pressure while heating. A method of melting and adhering the composition components in a layer, a reversible thermosensitive recording layer surface and / or a transparent film surface is coated with an adhesive to provide an adhesive layer, and both are superposed and heated and / or pressurized to adhere. Method, an adhesive is contained in the reversible thermosensitive recording layer,
Examples thereof include a method in which the both are overlapped and heated and / or pressed to bond them, but the method is not limited thereto.

Further, in the method of coating the surface of the reversible thermosensitive recording layer and / or the surface of the transparent film with an adhesive to form an adhesive layer, and superposing them on each other by heating and / or pressurizing them, Is contained in the reversible thermosensitive recording layer by repeatedly forming / erasing an image, and the reversibility of the formed image is prevented for the purpose of preventing deterioration of color density, decolorization density and stability of the formed image. An intermediate layer may be provided on the surface of the thermal recording layer in advance, an adhesive layer may be provided by coating the intermediate layer and / or the transparent film surface with an adhesive, and the both may be superposed and heated and / or pressed to adhere. it can.

As a method for adhering and integrating a support on the surface of the reversible thermosensitive recording layer formed on a transparent film, the reversible thermosensitive recording layer in the reversible thermosensitive recording layer is prepared by superposing the two and pressing them while heating. A method of melting and adhering the composition components therein, a reversible thermosensitive recording layer surface and / or a support surface is coated with an adhesive to provide an adhesive layer, and both are superposed and heated and / or pressurized to adhere. Examples of the method include, but are not limited to, a method in which an adhesive is contained in the reversible thermosensitive recording layer, and the both are superposed and heated and / or pressurized to adhere.

In the method of coating an adhesive on the surface of the reversible thermosensitive recording layer and / or the surface of the support to form an adhesive layer, and superposing them on each other by heating and / or applying pressure, Is contained in the reversible thermosensitive recording layer by repeatedly forming / erasing an image, and the reversibility of the formed image is prevented for the purpose of preventing deterioration of color density, decolorization density and stability of the formed image. An intermediate layer may be provided in advance on the surface of the thermal recording layer, an adhesive layer may be provided by coating the intermediate layer and / or the surface of the support with an adhesive, and the two may be superposed and heated and / or pressurized to adhere. it can.

As a method of incorporating a colorless or light-colored electron-donating dye precursor and a reversible developer into a reversible thermosensitive recording layer, each compound is dissolved in a solvent or dispersed in a dispersion medium. A method of mixing, a method of dissolving each compound in a solvent or dispersing in a dispersion medium, a method of dissolving each compound by heating and homogenizing and then cooling, and a method of dissolving in a solvent or dispersing in a dispersion medium, etc. However, it is not specified.

The reversible thermosensitive recording layer is obtained by finely pulverizing each color-forming component, mixing respective dispersions, coating and drying on a support, and each color-forming component dissolved in a solvent. It can be obtained by a method in which the solutions are mixed, coated on a support and dried. In this case, for example, each color-forming component may be contained in one layer to form a multilayer structure.

It is also possible to add a binder to the reversible thermosensitive recording layer 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. 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 Examples include, but are not limited to, latexes such as esters, styrene / butadiene copolymers, acrylonitrile / butadiene copolymers, methyl acrylate / butadiene copolymers, ethylene / vinyl acetate copolymers. No.

A heat-fusible substance may 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 for general thermal recording paper. 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, p-benzylbiphenyl, and 4
Biphenyl derivatives such as allyloxybiphenyl, 1,
2-bis (3-methylphenoxy) ethane, 2,2'-
Polyether compounds such as bis (4-methoxyphenoxy) diethyl ether, bis (4-methoxyphenyl) ether, carbonic acid such as diphenyl carbonate, dibenzyl oxalate, bis (p-methylbenzyl) oxalate, or oxalic acid diester derivatives And two or more kinds can be used 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 film, synthetic resin laminated paper, synthetic paper, metal foil, glass and the like, or a combination thereof is used. The composite sheet can be arbitrarily used depending on the purpose, but is not limited thereto. Further, these may be opaque, semi-transparent, or transparent.

The reversible thermosensitive recording material of the present invention, if necessary, in the reversible thermosensitive recording layer and / or on the surface of the support on which the reversible thermosensitive recording layer is provided or on the opposite side,
A material that can record information electrically, magnetically, or optically may be included. In addition, a back coat layer may be provided on the surface of the support opposite to the surface on which the reversible thermosensitive recording layer is provided for the purpose of preventing curling and preventing electrification.

In the reversible thermosensitive recording layer, pigments such as diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide and urea-formalin resin, A dispersant such as sodium dioctylsulfosuccinate, a surfactant, a fluorescent dye and the like can be added.

[0065]

In the reversible thermosensitive recording material of the present invention, unlike the case where the reversible thermosensitive recording layer is coated with a protective layer, a heat-resistant and abrasion-resistant transparent sheet acts as a protective layer. The protective layer formed by the coating method is a coating of an aqueous solution of a water-soluble resin such as a cellulose resin or polyvinyl alcohol, a polystyrene resin, a styrene copolymer, an acrylic resin, an acrylic copolymer, a methacrylic resin, a methacrylic copolymer, or a polyester. Resin, butyral resin,
Coating of water-based emulsion such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride / vinyl acetate copolymer, polyvinylidene chloride resin, polyurethane resin, polystyrene resin, styrene copolymer, acrylic resin,
Organic solvents such as acrylic copolymer, methacrylic resin, methacrylic copolymer, polyester resin, butyral resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride / vinyl acetate copolymer, polyvinylidene chloride resin, polyurethane resin It is formed by a method such as solution coating, acrylate electron beam curable resin, acrylate ultraviolet ray curable resin, or the like. Since the protective layer formed by such a coating method has low thermal and mechanical strength, deterioration such as shrinkage and cracking occurs due to repeated heating during image formation and erasing.
Although it functions as a protective layer in the initial stage of such deterioration, since the amount of heat reaching the reversible thermosensitive recording layer is large, the color density of the image area is increased with repeated heating during image formation and erasing. A phenomenon that gradually increases occurs. When the deterioration of the protective layer further progresses, the function of the protective layer begins to be lost, and the deterioration of the reversible thermosensitive recording layer progresses. As the deterioration of the reversible thermosensitive recording layer progresses, the coloring of the image area is reduced due to repeated heating during image formation and erasing, and the contrast between the image area and the non-image area is impaired. Also,
In the coating method, it is unavoidable that the resin itself, the resin dispersant contained in the emulsion, and the monomers in the electron beam curable resin and the ultraviolet curable resin infiltrate into the reversible thermosensitive recording layer. It is a protective layer formed by the coating method, because it prevents the erasing and erasing at the time of erasing. It is excellent in the durability against repeated heating during image formation and erasing, and the coloring in the image forming area and the erasing in the erasing area are good. It is extremely difficult to realize a reversible thermosensitive recording material. The problem with the protective layer formed by such a coating method is that the protective layer is formed on the reversible thermosensitive recording layer. It can be solved by disposing it on the recording layer.

According to the constitution of the reversible thermosensitive recording material of the present invention, the heat resistance of the protective layer and the abrasion resistance of the transparent sheet are
The mechanical strength is extremely high, the change in the color density of the image forming portion is extremely small even when the image forming and erasing are repeated, and a reversible thermosensitive recording material having high repeating durability can be realized. Further, the erasing density of the erasing portion is also superior to that of the reversible thermosensitive recording material having the protective layer formed by the coating method.

The present invention will be described in more detail with reference to the following examples.

[0068]

【Example】

Example 1 (A) Preparation of reversible heat-sensitive coating liquid 2.5 parts of 40 parts of 3-di-n-butylamino-6-methyl-7-anilinofluorane, which is an electron-donating dye precursor, is used.
% Polyvinyl alcohol aqueous solution together with a ball mill for 24 hours to obtain a dye precursor dispersion. Next, 100 parts of N '-(4-hydroxyphenyl) -N-octadecylurea was pulverized with 400 parts of a 2.5% aqueous solution of polyvinyl alcohol in a ball mill for 24 hours to obtain a dispersion liquid. After mixing the above two kinds of dispersions, 200 parts of a 10% polyvinyl alcohol aqueous solution and 400 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 coating solution prepared in (A) was applied to a white polyethylene terephthalate (PET) sheet having a thickness of 188 μm so that the solid content was 4 g / m ² . After smearing, drying, and processing with a super calendar. A transparent polyethylene terephthalate film having a thickness of 5 μm was superposed on the surface of the reversible thermosensitive recording layer and closely adhered to each other, and then passed through a super calender heated at 120 ° C. to integrate the two, and a white polyethylene terephthalate (PET) sheet was prepared as a support. A reversible thermosensitive recording material was obtained.

Example 2 The reversible heat-sensitive coating liquid prepared in (A) of Example 1 was applied to a thickness of 5 μm.
m transparent polyethylene terephthalate film was smeared so that the solid content smeared amount was 4 g / m ² , dried and then treated with a super calendar. After a white polyethylene terephthalate (PET) sheet having a thickness of 188 μm was superposed on the surface of the reversible thermosensitive recording layer and closely adhered thereto, 12
Both were passed through a super calender heated to 0 ° C. to integrate them, and a reversible thermosensitive recording material having a white polyethylene terephthalate (PET) sheet as a support was obtained.

Example 3 The reversible heat-sensitive coating liquid prepared in (A) of Example 1 was applied to a thickness of 18
A transparent polyethylene terephthalate (PET) sheet having a thickness of 8 μm was smeared so that the solid content smeared amount was 4 g / m ² , dried, and treated with a super calendar. The surface of the reversible heat-sensitive recording layer is coated with a polyester resin adhesive in a thickness of about 2 μm, and a transparent polyethylene terephthalate film having a thickness of 5 μm is superposed and well adhered on the surface to form a transparent polyethylene terephthalate (PET) film. ) A transparent reversible thermosensitive recording material having a sheet as a support was obtained.

Comparative Example 1 The reversible heat-sensitive coating liquid prepared in (A) of Example 1 was applied to a thickness of 18
Smear it onto a white polyethylene terephthalate (PET) film having a thickness of 8 μm so that the solid content is 4 g / m ² .
After drying, it was processed with a super calendar. The surface of the reversible thermosensitive recording layer of this film was coated with polyvinyl alcohol in a thickness of 5 μm to provide a protective layer, and a reversible thermosensitive recording material having a white polyethylene terephthalate sheet as a support was obtained.

Comparative Example 2 The reversible heat-sensitive coating liquid prepared in (A) of Example 1 was applied to a thickness of 18
Smear it onto a white polyethylene terephthalate (PET) film having a thickness of 8 μm so that the solid content is 4 g / m ² .
After drying, it was processed with a super calendar. The surface of the reversible thermosensitive recording layer of this film was coated with a methyl polyacrylate resin in a thickness of 5 μm to provide a protective layer, and a reversible thermosensitive recording material having a white polyethylene terephthalate sheet as a support was obtained.

Comparative Example 3 The reversible heat-sensitive coating liquid prepared in (A) of Example 1 was applied to a thickness of 25.
A 0 μm paper sheet was smeared so that the solid content smeared amount was 4 g / m ² , dried and then treated with a super calendar. The surface of the reversible thermosensitive recording layer of this film was coated with an epoxy resin in a thickness of 5 μm to provide a protective layer, and a reversible thermosensitive recording material using a paper sheet as a support was obtained.

Test 1 (coloring density = thermoresponsiveness) The reversible thermosensitive recording materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were mixed 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 1.0 millisecond under an applied voltage of 26 V, and the density of the obtained color image was measured using a densitometer Macbeth RD918. The results are shown in Table 1.

Test 2 (Repeating Test of Image Forming / Erasing) The reversible thermosensitive recording materials obtained in Examples 1 to 3 and Comparative Examples 1 to 3 were mixed with Kyocera print head KJT-256-8MGF.
Okura Electric Thermal Printing Tester TH-P with 1
Applying an applied voltage of 26 with an applied pulse of 1.0 ms using MD
An image was formed by printing under the condition of bolt. Next, the image forming part was erased by heating with a heat stamp at 120 ° C. for 1 second. Image formation / erasure was repeated in the same manner, and the density of the 100th image forming portion and the density of the 100th image erasing portion were measured using a densitometer Macbeth RD918. The results are shown in Table 1.

Test 3 (Functional test of protective layer after 100 times of image forming / erasing) Writing on the 100th image forming portion obtained in Test 2 with a pink highlighter, and observing changes in image did. The results are shown in Table 1.

[0079]

[Table 1]

[0080]

As shown in Table 1, a colorless or light-colored electron-donating dye precursor and a dye precursor having a reversible color tone change due to a difference in cooling rate after heating are supported on a support. An image can be formed / erased with a good contrast by the reversible thermosensitive recording material in which a reversible thermosensitive recording layer mainly containing a reversible color developing agent and a heat-resistant and abrasion-resistant transparent sheet are sequentially laminated. It was possible to obtain a reversible thermosensitive recording material with little deterioration in image quality even after repeated image formation / erasing.

Claims (1)

[Claims] 1. A usually colorless or light-colored electron-donating dye precursor 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 thermosensitive recording material mainly composed of a reversible thermosensitive recording layer and a heat-resistant and abrasion-resistant transparent sheet which are successively laminated.