JPH06155905A - Repeated formation of image - Google Patents

Abstract

(57) [Summary] [Purpose] It is possible to make appropriate corrections after checking the printed contents such as documents and drawings with a thermal printer, and to repeat the process because the image formed thermally can be erased by leaving it naturally. PROBLEM TO BE SOLVED: To provide a heat-sensitive recording medium that can be used, to provide a method for repeatedly displaying clear printing with good contrast on the recording medium by using the recording medium, and a method for correcting or erasing an image displayed on the recording medium. To do. [Structure] A reversible thermochromic composition containing an electron-donating color-developing organic compound and an electron-accepting compound can be changed to a decolorized state without heating the composition in a colored state. Using a reversible thermosensitive recording medium in which a recording layer containing a composition to which a color erasing agent is added is provided on a support, the step of forming a color recording state by heat application and the color recording state obtained in the step A method for repeatedly forming an image, which comprises repeatedly performing an erasing step of erasing a recording medium in a natural environment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for repeatedly forming images using a reversible thermosensitive recording medium.

[0002]

2. Description of the Related Art A printing system using a device such as a word processor is widely used in offices and general households. In the process of creating documents, drawings, etc. with this device, it is common to print out the images displayed on the display by input without sufficiently checking, proofreading, or correcting the sentences and layout, and typographical errors and omissions. Therefore, the above-mentioned work is performed on the printed matter printed out. Further, even if a sufficient confirmation work is performed on the display, it is often necessary to further correct it due to various circumstances, so that the amount of wasteful printing paper is enormous. Furthermore, in thermal printers that use thermal heads, waste of consumables such as ink ribbons is large, and there are some cases in which correction work printing is performed on thermal paper to improve this, but this is a drastic improvement method. Absent.

By the way, Japanese Laid-Open Patent Publication No. 60-52388 discloses a paper recycling printing system using a thermal printer. This is for the purpose of reusing printing paper, using a thermo sheet coated with a reversible thermosensitive material at low temperature such as Ag ₂ HgI ₄ , and when the compound is cooled to 5 ° C or lower, the color before applying heat is changed. Take advantage of returning. However, Ag ₂ HgI ₄ changes its color from yellow to yellow-orange when heat is applied, so that the contrast is poor and there is a problem that a cooling device is required to restore the state before heat application. In addition to this, various methods have been proposed in connection with the reuse of printing paper. For example, Japanese Patent Application Laid-Open No. 1-90582 discloses a method in which a sheet on which ink does not soak is printed, and the sheet is wiped with an erasing liquid to be reproduced. Japanese Patent Application Laid-Open No. 2-55195 discloses a method of dissolving and removing ink by overlaying an ink peeling body on what is printed on a release layer on the surface of a support, and transferring a color developed on the side of the ink peeling body through a heat roller. .Removing method, JP-A-64-38742
JP-A No. 52-140483 discloses a method in which a heat-sensitive material is made photochromic and repeatedly used, and an electron-donating color-forming organic compound and a hydroxybenzoic acid ester derivative as an electron-accepting compound are disclosed. Methods of using the constructed thermochromic materials are each presented.

In the known methods described above,
The method requires an ink removing device, an erasing liquid for removing the ink, a solvent, and a peeling body, and there is a problem in the reprocessing of these ink removing consumables. In addition, since the method of (1) requires ultraviolet irradiation, many problems remain in the light source, sensitivity, stability, etc. Improvement is needed.
That is, none of the known methods described above is a method that can be fully satisfied, and there are many points to be improved before implementation. As described in detail above, the large amount of waste paper discharge associated with OA has been of interest since the beginning of OA. It strongly indicates that various treatments are necessary. However, up to the present, no suitable reuse method has been found.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems associated with the reuse of printed matter printed out and makes appropriate corrections after confirming the print contents of a document or drawing by a thermal printer. It is an object of the present invention to provide a reversible heat-sensitive recording method using a heat-sensitive recording medium that can be repeatedly used because it is possible to erase an image that is thermally formed by leaving it naturally. It is a method including a step of forming a colored recording state by application and a step of leaving the recording medium in the colored recording state obtained in the step in a natural environment to erase the color.

[0006]

The present inventor has completed the present invention as a result of intensive studies to solve the above-mentioned problems. That is, according to the present invention, a reversible thermochromic composition containing an electron-donating color-developing organic compound and an electron-accepting compound is brought into a decolorized state without heating the composition in the colored state. Using a reversible thermosensitive recording medium in which a recording layer containing a composition containing a changeable decoloring agent is provided on a support, and a color recording state forming step by heat application,
There is provided a method for repeatedly forming an image, which is characterized in that the erasing step of leaving the recording medium in the color-recorded recording state obtained in the step for erasing in a natural environment is repeated.

Electron-donating color-developing organic compound (hereinafter also referred to as color-developing agent) and electron-accepting compound used in the present invention
(Hereinafter, also referred to as a color developing agent) is an application relating to a reversible thermosensitive recording medium previously filed by the present inventors (Japanese Patent Application No. 3-3550).
No. 78) and the same kind. Further, the decolorizer used in the present invention includes higher alcohols,
Includes higher esters and higher amides. As the decoloring agent, one kind or a mixture of two or more kinds selected from the above may be used. The decoloring speed depends on the kind and amount of the decoloring agent added to the recording medium used in the present invention. Can be controlled. The reversible thermochromic composition used for the recording medium in the present invention is generally a composition that is colorless at the time of bleaching and instantaneously develops color upon heating. It is desirable to use blue, green, etc. as the color tone. However, the coloring color tone is not limited to the above. Needless to say, it can be used if a sufficiently clear image can be obtained even if it is colored in a light color when not in use.

The reversibility of the thermochromic composition in the present invention is basically achieved only by the combination of the color developing agent and the color developing agent. The color developing agent has a structure having color developing ability and an alkyl chain having 5 or more carbon atoms in its molecule, and reversibility is imparted when combined with a suitable color developing agent. This combination is selected depending on whether or not a sample in a colored state obtained by rapidly cooling both after heating and melting is subjected to differential scanning calorimetric analysis or differential thermal analysis and shows exothermic development in the temperature rising process. If shown, it can be used in the present invention. This reversible thermochromic composition can be brought into a color-developed state by temporarily heating it to a temperature at which the developer and the color-developing agent are mixed and melted to generate a color or higher and then rapidly cooling the mixture. In this color-developed state, it is presumed that the color-developing agent and the color-developing agent form a regular aggregation structure, and this aggregation structure is considered to be due to the cohesive force of the alkyl chain of the color-developing agent. And this aggregate structure is stably maintained at room temperature in the absence of the decolorizing agent, but when the decoloring agent is present, it enters the inside of the aggregating structure to promote the separation of the color former and the developer. It is estimated that erasing proceeds at a moderate speed. The effect of promoting separation in this case is not sufficiently clear, but the decoloring agent that has entered the inside of the color-developing body may occur by dissolving the color-developing agent and / or the color-developing agent.

In the present invention, the color developing agent used in combination with the color developing agent and the color erasing agent contained in the reversible thermochromic composition basically has a color developing ability capable of developing a color in the molecule. And a compound having an alkyl chain structure having 5 or more carbon atoms for controlling the cohesive force between molecules,
An organic phosphoric acid compound having an aliphatic group having 12 or more carbon atoms, an aliphatic carboxylic acid compound, a phenol compound, or a metal salt of mercaptoacetic acid having an aliphatic group having 10 to 18 carbon atoms,
Alternatively, it is an alkyl ester of caffeic acid having an alkyl group having 5 to 8 carbon atoms. The aliphatic group includes a linear or branched alkyl group and alkenyl group, and may have a substituent such as halogen, an alkoxy group and an ester group.

As the organic phosphoric acid compound, an alkylphosphonic acid compound represented by the following general formula (1) is used. R ₁ -PO (OH) ₂ (1) More specifically an organic phosphoric acid compound represented by (wherein, R ₁ represents more than 12 aliphatic group having a carbon number) In formula (1), dodecylphosphonic Acid, tetradecylphosphonic acid,
Hexadecylphosphonic acid, octadecylphosphonic acid, eicosylphosphonic acid, docosylphosphonic acid, tetracosylphosphonic acid, hexacosylphosphonic acid, octacosylphosphonic acid and the like can be mentioned.

As the organic phosphoric acid compound, α-hydroxyalkylphosphonic acid represented by the following general formula (2) can also be used. (However, R ₂ is an aliphatic group having 11 to 29 carbon atoms.) Specific examples of the α-hydroxyalkylphosphonic acid represented by the general formula (3) include α-hydroxydodecylphosphonic acid and α-hydroxy. Examples thereof include tetradecylphosphonic acid, α-hydroxyhexadecylphosphonic acid, α-hydroxyoctadecylphosphonic acid, α-hydroxyeicosylphosphonic acid, α-hydroxydocosylphosphonic acid, and α-hydroxytetracosylphosphonic acid.

As the aliphatic carboxylic acid compound, α-hydroxy fatty acids represented by the following general formula (3) are used. R ₃ —CH (OH) —COOH (3) (wherein R ₃ represents an aliphatic group having 12 or more carbon atoms) The α-hydroxyaliphatic carboxylic acid compound represented by the general formula (3) is specifically described. To show, α-hydroxydodecanoic acid, α-hydroxytetradecanoic acid, α-hydroxyhexadecanoic acid, α-hydroxyoctadecanoic acid, α-hydroxypentadecanoic acid, α-hydroxyeicosanoic acid, α-hydroxydocosanoic acid, α-hydroxy Examples thereof include tetracosanoic acid, α-hydroxyhexacosanoic acid and α-hydroxyoctacosanoic acid.

The aliphatic carboxylic acid compound is an aliphatic carboxylic acid compound having an aliphatic group having a carbon number of 12 or more, which is substituted with a halogen element, and is at least in the α-position or β-position.
Also used is one having a halogen element in the carbon of the position. Specific examples of such compounds include 2-chlorooctadecanoic acid, heptadecaflornonadecanoic acid, 2-bromohexadecanoic acid, 2-bromoheptadecanoic acid, 2-bromooctadecanoic acid, 2-bromoeicosanoic acid, 2 -Bromodocosanoic acid, 2-bromotetracosanoic acid, 3-bromooctadecanoic acid, 3-bromoeicosanoic acid, 2,3-dibromooctadecanoic acid, 2-flordodecanoic acid, 2-flortetradecanoic acid, 2-fluorohexadecanoic acid, 2 -Fluorooctadecanoic acid, 2-fluoroeicosanoic acid, 2-flordocosanoic acid, 2-iodohexadecanoic acid, 2-iodooctadecanoic acid, 3-iodohexadecanoic acid, 3-iodooctadecanoic acid, perfluorooctadecanoic acid and the like.

The aliphatic carboxylic acid compound is an aliphatic carboxylic acid compound having an oxo group having 12 or more carbon atoms in the carbon chain, and at least the carbon at the α-position, β-position or γ-position is oxo. The underlying one is also used. Specific examples of such compounds include 2-oxododecanoic acid, 2-oxotetradecanoic acid, 2-oxohexadecanoic acid, 2-oxooctadecanoic acid, 2-oxoeicosanoic acid, 2-oxotetracosanoic acid and 3-oxotetradecanoic acid. Oxododecanoic acid, 3-oxotetradecanoic acid, 3-oxohexadecanoic acid, 3-oxooctadecanoic acid, 3-oxoeicosanoic acid, 3-oxotetracosanoic acid, 4-oxohexadecanoic acid, 4-oxoheptadecanoic acid, 4 Examples include -oxooctadecanoic acid and 4-oxodocosanoic acid.

As the aliphatic carboxylic acid compound, a dibasic acid represented by the following general formula (4) is also used. (However, R ₄ represents an aliphatic group having 12 or more carbon atoms, X represents an oxygen atom or a sulfur atom, and n represents 1 or 2,
Xn may be a —SO ₂ — group) Specific examples of the dibasic acid represented by the general formula (4) include dodecylmalic acid, tetradecylmalic acid, hexadecylmalic acid, octadecylmalic acid, and eico. Silmalic acid, docosylmalic acid, tetracosylmalic acid, dodecylthiomalic acid, tetradecylthiomalic acid, hexadecylthiomalic acid, octadecylthiomalic acid, eicosylthiomalic acid, docosylthiomalic acid, tetracosylthio Malic acid, dodecyldithiomalic acid, tetradecyldithiomalic acid, hexadecyldithiomalic acid, octadecyldithiomalic acid, eicosyldithiomalic acid,
Docosyl dithiomalic acid, tetracosyl dithiomalic acid, dodecyl sulfone butanedioic acid, tetradecyl sulfone butanedioic acid, hexadecyl sulfone butanedioic acid, octadecyl sulfone butanedioic acid, eicosyl sulfone butanedioic acid, dodecyl sulfone butane diacid Acid etc. are mentioned.

As the aliphatic carboxylic acid compound, a dibasic acid represented by the following general formula (5) is also used. (However, R ₅ , R ₆ , and R ₇ represent hydrogen or an aliphatic group,
At least one of these is an aliphatic group having 12 or more carbon atoms.) Specific examples of the dibasic acid represented by the general formula (5) include dodecyl butanedioic acid, tridecyl butanedioic acid, and tetradecyl butanedioic acid. Acid, pentadecyl butanedioic acid, octadecyl butanedioic acid, eicosyl butanedioic acid, docosyl butanedioic acid, 2,3-dihexadecyl butanedioic acid, 2,3-dioctadecyl butanedioic acid, 2-methyl-3- Dodecyl butanedioic acid, 2-methyl-3-tetradecyl butanedioic acid, 2
-Methyl-3-hexadecyl butanedioic acid, 2-ethyl-
Examples thereof include 3-dodecyl butanedioic acid, 2-propyl-3-dodecyl butanedioic acid, 2-octyl-3-hexadecyl butanedioic acid, and 2-tetradecyl-3-octadecyl butanedioic acid.

As the aliphatic carboxylic acid compound, a dibasic acid represented by the following general formula (6) is also used. (However, R ₈ and R ₉ represent hydrogen or an aliphatic group, and at least one of them is an aliphatic group having 12 or more carbon atoms.) Specific examples of the dibasic acid represented by the general formula (6) Is dodecylmalonic acid, tetradecylmalonic acid, hexadecylmalonic acid, octadecylmalonic acid, eicosylmalonic acid, docosylmalonic acid, tetracosylmalonic acid, didodecylmalonic acid, ditetradecylmalonic acid, dihexadecylmalonic acid , Dioctadecylmalonic acid, dieicosylmalonic acid, didocylmalonic acid, methyloctadecylmalonic acid, methyleicosylmalonic acid, methyldocosylmalonic acid, methyltetracosylmalonic acid, ethyloctadecylmalonic acid, ethyleicosylmalonic acid, Examples thereof include ethyldocosylmalonic acid and ethyltetracosylmalonic acid.

As the aliphatic carboxylic acid compound, a dibasic acid represented by the following general formula (7) is also used. (However, R ₁₀ represents an aliphatic group having 12 or more carbon atoms, n represents 0 or 1, m represents 1, 2 or 3, and when n is 0, m is 2 or 3, and n When is 1, m is 1 or 2
A specific example of the dibasic acid represented by the general formula (7) is 2
-Dodecyl-pentanedioic acid, 2-hexadecyl-pentanedioic acid, 2-octadecyl-pentanedioic acid, 2-eicosyl-pentanedioic acid, 2-docosyl-pentanedioic acid, 2
-Dodecyl-hexanedioic acid, 2-pentadecyl-hexanedioic acid, 2-octadecyl-hexanedioic acid, 2-eicosyl-hexanedioic acid, 2-docosyl-hexanedioic acid and the like.

As the aliphatic carboxylic acid compound, a tribasic acid such as citric acid acylated with a long chain fatty acid can also be used. Specific examples thereof include the following.

The phenol compound is represented by the following general formula
The compound represented by (8) is used.

[Chemical 1] (However, Y is -S-, -O-, -CONH-, or -C.
OO-, R ₁₁ represents an aliphatic group having 12 or more carbon atoms, and n is an integer of 1, 2 or 3) Specific examples of the phenol compound represented by the general formula (8) include p- (Dodecylthio) phenol, p- (tetradecylthio) phenol, p- (hexadecylthio) phenol, p- (octadecylthio) phenol, p-
(Eicosylthio) phenol, p- (docosylthio) phenol, p- (tetracosylthio) phenol, p-
(Dodecyloxy) phenol, p- (tetradecyloxy) phenol, p- (hexadecyloxy) phenol, p- (octadecyloxy) phenol, p-
(Eicosyloxy) phenol, p- (docosyloxy) phenol, p- (tetracosyloxy) phenol, p-dodecylcarbamoylphenol, p-tetradecylcarbamoylphenol, p-hexadecylcarbamoylphenol, p-octadecylcarbamoylphenol, p-eicosylcarbamoylphenol, p
-Docosylcarbamoylphenol, p-tetracosylcarbamoylphenol, gallic acid hexadecyl ester, gallic acid octadecyl ester, gallic acid eicosyl ester, gallic acid docosyl ester, gallic acid tetracosyl ester and the like.

As the phenol compound, a caffeic acid alkyl ester represented by the following general formula (9) can also be used.

[Chemical 2] (However, R ₁₂ is an alkyl group having 5 to 8 carbon atoms) Specific examples of the caffeic acid alkyl ester represented by the general formula (9) include caffeic acid-n-pentyl and caffeic acid-n.
-Hexyl, caffeic acid-n-heptyl, caffeic acid-
Examples include n-octyl and the like.

As the metal salt of mercaptoacetic acid, a metal salt of an alkyl or alkenyl mercaptoacetic acid represented by the general formula (10) is used. (R ₁₃ —S—CH ₂ —COO) ₂ M (10) (wherein R ₁₃ represents an aliphatic group having 10 to 18 carbon atoms, and M
Represents tin, magnesium, zinc or copper). Specific examples of the mercaptoacetic acid metal salt represented by the general formula (10) include decylmercaptoacetic acid tin salt, dodecylmercaptoacetic acid tin salt, tetradecylmercaptoacetic acid tin salt, and hexa. Decylmercaptoacetic acid tin salt, octadecylmercaptoacetic acid tin salt, decylmercaptoacetic acid magnesium salt, dodecylmercaptoacetic acid magnesium salt, tetradecylmercaptoacetic acid magnesium salt, hexadecylmercaptoacetic acid magnesium salt, octadecylmercaptoacetic acid magnesium salt, decylmercaptoacetic acid zinc salt,
Dodecyl mercapto acetic acid zinc salt, tetradecyl mercapto acetic acid zinc salt, hexadecyl mercapto acetic acid zinc salt, octadecyl mercapto acetic acid zinc salt, decyl mercapto acetic acid copper salt, dodecyl mercapto acetic acid copper salt, tetradecyl mercapto acetic acid copper salt, hexadecyl mercapto acetic acid copper salt salt,
Octadecyl mercaptoacetic acid copper salt etc. are mentioned.

The reversible thermochromic composition used in the present invention is formed by combining the above-mentioned color developer with a color former and a decolorizer. The color former exhibits an electron donating property, and is itself a colorless or light-colored dye precursor, and is not particularly limited, and conventionally known ones such as triphenylmethanephthalide compound, fluorane compound,
Phenothiazine compounds, leuco auramine compounds,
An indolinophtalide compound or the like is used. Specific examples of the color former are shown below. A preferred color former used in the present invention is a fluorane compound represented by the following general formula (11).

[Chemical 3] (In the formula, R ₁₄ represents a hydrogen atom, an alkyl group, an allyl group, a cyclic alkyl group, or an alkoxyalkyl group, and R ₁₅ represents an alkyl group, a cyclic alkyl group, an allyl group, an alkoxyalkyl group, or a substituent. Represents a good phenyl group, X represents a hydrogen atom, a lower alkyl group, a lower alkoxy group, an alkoxyalkyl group, or a halogen atom.
Y represents a lower alkyl group, an amino group, a substituted amino group, a cyano group, or a halogen atom. )

Specific examples of the compound represented by the general formula (11) include the following compounds. 2-anilino-3-methyl-6- (Nn-hexyl-N-iso-amylamino) fluorane, 2-anilino-3-methyl-6-
(Di-n-hexylamino) fluorane, 2-anilino-3-methyl-6- (di-n-amylamino) fluorane, 2-anilino-3-methyl-6- (di-n-octylamino) fluorane, 2 -Anilino-3-methyl-6
-(Di-n-butylamino) fluorane, 2-anilino-3-methyl-6- (N-isopropyl-N-methylamino) fluorane, 2-anilino-3-methyl-6-
(Nn-octyl-N-ethylamino) fluorane,
2-anilino-3-methyl-6- (Nn-octyl-
N-iso-propylamino) fluorane, 2-anilino-3-methyl-6- (Nn-amyl-Nn-propylamino) fluorane, 2-anilino-3-methyl-
6- (Nn-amyl-Nn-butylamino) fluorane, 2-anilino-3-methyl-6- (Nn-amyl-N-ethylamino) fluorane, 2-anilino-3
-Methyl-6- (N-n-amyl-N-methylamino)
Fluoran, 2-anilino-3-methyl-6- (N-i
so-amyl-N-ethylamino) fluorane, 2-anilino-3-methyl-6- (Nn-propyl-N-isopropylamino) fluorane, 2-anilino-3-methyl-6- (Nn-) Butyl-N-n-propylamino) fluorane, 2-anilino-3-methyl-6- (N
-Ethyl-N-sec-butylamino) fluorane, 2
-Anilino-3-methyl-6- (Nn-butyl-N-
iso-propylamino) fluorane, 2-anilino-
3-Methyl-6- (Nn-butyl-N-ethylamino) fluorane, 2-anilino-3-methyl-6- (N
-Isobutyl-N-methylamino) fluorane.

2-anilino-3-methyl-6- (N-cyclohexyl-Nn-tetradecylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-Nn-dodecylamino) Fluoran, 2-anilino-3-methyl-6- (N-cyclohexyl-Nn
-Decylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-Nn-octylamino) fluorane, 2-anilino-3-methyl-6- (N
-Cyclohexyl-Nn-hexylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-Nn-amylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-) N-is
o-amylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-Nn-butylamino) fluorane, 2-anilino-3-methyl-6- (N
-Cyclohexyl-Nn-propylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexyl-N-ethylamino) fluorane, 2-anilino-
3-Methyl-6- (N-cyclohexyl-N-methylamino) fluorane, 2-anilino-3-methyl-6-
(Dicyclohexylethylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexylethyl-Nn-hexylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexylethyl-N-
n-amylamino) fluorane, 2-anilino-3-methyl-6- (dicyclohexylmethylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexylmethyl-Nn-hexylamino) fluorane, 2
-Anilino-3-methyl-6- (N-cyclohexylmethyl-Nn-amylamino) fluorane, 2-anilino-3-methyl-6- (N-cyclohexylmethyl-N
-N-butylamino) fluorane, 2-anilino-3-
Methyl-6- (N-cyclohexylmethyl-N-cyclohexylamino) fluorane.

2-anilino-3-methyl-6- (diallylamino) fluorane, 2-anilino-3-methyl-6
-(Nn-octyl-N-allylamino) fluorane, 2-anilino-3-methyl-6- (Nn-hexyl-N-allylamino) fluorane, 2-anilino-3
-Methyl-6- (Nn-amyl-N-allylamino)
Fluorane, 2-anilino-3-methyl-6- (N-ethyl-N-allylamino) fluorane, 2-anilino-
3-Methyl-6- (N-2-ethoxypropyl-N-ethylamino) fluorane, 2-anilino-3-methyl-
6- (diethoxyethylamino) fluorane, 2-anilino-3-methyl-6- (N-ethoxyethyl-Nn)
-Hexylamino) fluorane, 2-anilino-3-methyl-6- (N-ethoxyethyl-Nn-amylamino) fluorane, 2-anilino-3-methyl-6- (N
-Ethoxyethyl-N-iso-amylamino) fluorane, 2-anilino-3-methyl-6- (N-ethoxyethyl-Nn-butylamino) fluorane, 2-anilino-3-methyl-6- (N- Ethoxyethyl-N-ethylamino) fluorane, 2-anilino-3-methyl-
6- (N-ethoxymethyl-Nn-hexylamino)
Fluorane, 2-anilino-3-methyl-6- (N-ethoxymethyl-Nn-amylamino) fluorane, 2
-Anilino-3-methyl-6- (N-ethoxymethyl-
N-iso-amylamino) fluorane, 2-anilino-3-methyl-6- (Nn-hexadecylamino) fluorane, 2-anilino-3-methyl-6- (Nn-)
Octylamino) fluorane, 2-anilino-3-methyl-6- (Nn-hexylamino) fluorane, 2-
Anilino-3-methyl-6- (N-ethyl-p-toluidino) fluorane, 2-anilino-3-methyl-6-
(N-methyl-p-toluidino) fluorane,

2-anilino-3-methoxy-6- (di-
n-hexylamino) fluorane, 2-anilino-3-
Methoxy-6- (di-n-amylamino) fluorane,
2-anilino-3-methoxy-6- (Nn-hexyl-N-iso-amylamino) fluorane, 2-anilino-3-methoxy-6- (N-cyclohexyl-Nn
-Hexylamino) fluorane, 2-anilino-3-ethoxy-6- (di-n-amylamino) fluorane, 2
-Anilino-3-ethoxy-6- (di-n-butylamino) fluorane, 2-anilino-3-ethoxy-6-diethylaminofluorane, 2-anilino-3-ethoxy-6- (N-cyclohexyl-N- n-hexylamino) fluorane, 2-anilino-3-ethoxy-6-
(N-cyclohexyl-Nn-amylamino) fluorane, 2-anilino-3-ethoxyethyl-6- (di-
n-amylamino) fluorane, 2-anilino-3-ethoxyethyl-6- (di-n-butylamino) fluorane, 2-anilino-3-ethoxyethyl-6-diethylaminofluorane, 2-anilino-3-ethoxymethyl -6- (Di-n-butylamino) fluorane, 2-anilino-3-ethoxymethyl-6- (N-cyclohexyl-Nn-hexylamino) fluorane, 2-anilino-3-ethoxymethyl-6- ( Di-n-amylamino)
Fluoran, 2-anilino-3-methoxymethyl-6-
(N-cyclohexyl-Nn-hexylamino) fluorane, 2-benzylamino-3-methyl-6- (di-
n-butylamino) fluorane, 2-benzylamino-
3-methyl-6- (di-n-amylamino) fluorane, 2-benzylamino-3-methyl-6- (N-cyclohexyl-Nn-hexylamino) fluorane, 2
-(M-Trichloromethylanilino) -3-methyl-6
-Diethylaminofluorane, 2- (m-trifluoromethylanilino) -3-methyl-6-diethylaminofluorane, 2- (m-trifluoromethylanilino) -3-
Methyl-6- (N-cyclohexyl-N-methylamino) fluorane, 2- (2,4-dimethylanilino)-
3-Methyl-6- (Nn-hexyl-N-iso-amylamino) fluorane, 2- (2,4-dimethylanilino) -3-methyl-6- (di-n-hexylamino)
Fluoran, 2- (2,4-dimethylanilino) -3-
Methyl-6- (di-n-amylamino) fluorane, 2
-(2,4-Dimethylanilino) -3-methyl-6-
(Di-n-butylamino) fluorane, 2- (2,4-
Dimethylanilino) -3-methyl-6-diethylaminofluorane, 2- (N-ethyl-p-toluidino) -3
-Methyl-6- (N-ethylanilino) fluorane, 2
-(N-methyl-p-toluidino) -3-methyl-6-
(N-propyl-p-toluidino) fluorane,

2-anilino-6- (di-n-hexylamino) fluorane, 2-anilino-6- (Nn-hexyl-N-iso-amylamino) fluorane, 2-anilino-6- (di-n) -Amylamino) fluoran, 2
-Anilino-6-diethylaminofluorane, 2-anilino-6- (Nn-hexyl-N-ethylamino) fluorane, 2-anilino-6- (N-cyclohexyl-
N-n-hexylamino) fluorane, 2-anilino-
6- (N-cyclohexyl-Nn-amylamino) fluorane, 2-anilino-6- (N-cyclohexyl-
N-methylamino) fluorane, 2-anilino-6-
(Diethoxyethylamino) fluorane, 2-anilino-6- (N-ethoxyethyl-N-iso-amylamino) fluorane, 2-anilino-6- (N-ethoxyethyl-Nn-amylamino) fluorane, 2- Anilino-6- (N-ethoxyethyl-Nn-butylamino) fluorane, 2-anilino-6- (Nn-octylamino) fluorane, 2-anilino-6- (Nn-)
Hexylamino) fluorane, 2-anilino-6- (N
-N-amylamino) fluorane, 2- (N-methylanilino) -6- (N-ethyl-p-toluidino) fluorane, 2- (o-chloroanilino) -6-diethylaminofluorane, 2- (o-bromoanilino)- 6-diethylaminofluorane, 2- (o-chloroanilino)-
6-dibutylaminofluorane, 2- (o-fluoroanilino) -6-dibutylaminofluorane, 2- (p-chloroanilino) -6- (Nn-octylamino) fluorane, 2- (p-chloranilino)- 6- (N-n-
Palmitylamino) fluorane, 2- (p-chloroanilino) -6- (di-n-octylamino) fluorane,
2- (m-trifluoromethylanilino) -6-diethylaminofluorane, 2- (p-acetylanilino) -6
-Diethylaminofluorane, 2- (p-acetylanilino) -6- (Nn-hexyl-N-iso-hexylamino) fluorane, 2- (p-acetylanilino)
-6- (di-n-hexylamino) fluorane, 2-
(P-Acetylanilino) -6- (Nn-hexyl-
N-n-amylamino) fluorane, 2- (p-acetylanilino) -6- (di-n-amylamino) fluorane, 2- (p-acetylanilino) -6- (Nn-amyl-N-) n-butylamino) fluorane, 2- (p-
Acetylanilino) -6- (N-cyclohexyl-N-
n-hexylamino) fluorane, 2- (p-acetylanilino) -6- (N-ethoxyethyl-N-iso-
Amylamino) fluorane, 2- (p-acetylanilino) -6- (N-ethoxyethyl-Nn-amylamino) fluorane,

2-benzylamino-6- (N-ethyl-
p-toluidino) fluorane, 2-benzylamino-6
-(N-methyl-2,4-dimethylanilino) fluorane, 2-benzylamino-6- (N-ethyl-2,4-
Dimethylanilino) fluorane, 2-benzoylamino-6- (N-ethyl-p-toluidino) fluorane, 2
-(O-Methoxybenzoylamino) -6- (N-methyl-p-toluidino) fluorane, 2-dibenzylamino-6- (di-n-butylamino) fluorane, 2-dibenzylamino-6- (di -N-amylamino) fluorane, 2-dibenzylamino-6- (di-n-hexylamino) fluorane, 2-dibenzylamino-6- (N
-N-hexyl-N-iso-amylamino) fluorane, 2-dibenzylamino-6- (di-n-propylamino) fluorane, 2-dibenzylamino-6- (N-
Cyclohexyl-N-n-amylamino) fluorane,
2-dibenzylamino-6- (N-cyclohexyl-N
-N-hexylamino) fluorane, 2-dibenzylamino-6- (N-methyl-p-toluidino) fluorane, 2-dibenzylamino-6- (N-ethyl-p-toluidino) fluorane, 2- (di -P-methylbenzylamino) -6- (N-ethyl-p-toluidino) fluorane, 2-dibenzylamino-4-methyl-6-diethylaminofluorane, 2-dibenzylamino-4-methyl-6- ( Di-n-propylamino) fluorane, 2-
Dibenzylamino-4-methyl-6- (di-n-butylamino) fluorane, 2-dibenzylamino-4-methyl-6- (di-n-amylamino) fluorane, 2-dibenzylamino-4-methoxy -6- (N-methyl-P
-Toluidino) fluorane, 2-benzylamino-4-
Methyl-6- (N-ethyl-P-toluidino) fluorane, 2- (α-phenylethylamino) -4-methyl-
6-Diethylaminofluorane, 2- (p-toluidino) -3- (t-butyl) -6- (N-methyl-p-toluidino) fluorane, 2- (α-phenylethylamino) -6- (N- Ethyl-p-toluidino) fluorane, 2- (o-methoxycarbonylanilino) -6-diethylaminofluorane,

2-Methylamino-6- (N-methylanilino) fluorane, 2-methylamino-6- (N-ethylanilino) fluorane, 2-methylamino-6- (N
-Propylanilino) fluorane, 2-ethylamino-
6- (N-methyl-p-toluidino) fluorane, 2-
Ethylamino-6- (N-ethyl-p-toluidino) fluorane, 2-methylamino-6- (N-methyl-2,
4, -Dimethylanilino) fluorane, 2-ethylamino-6- (N-ethyl-2,4, -dimethylanilino)
Fluorane, 2-dimethylamino-6- (N-methylanilino) fluorane, 2-dimethylamino-6- (N-
Ethylanilino) fluorane, 2-diethylamino-6
-(N-methyl-p-toluidino) fluorane, 2-diethylamino-6- (N-ethyl-p-toluidino) fluorane, 2-dipropylamino-6- (N-methylanilino) fluorane, 2-dipropylamino- 6- (N
-Ethylanilino) fluorane, 2-acetylamino-
3-Methyl-6-diethylaminofluorane, 2-acetylamino-3-methyl-6- (di-n-butylamino) fluorane, 2-acetylamino-3-methyl-6
-(Di-n-amylamino) fluorane, 2-acetylamino-3-methyl-6- (di-n-hexylamino)
Fluoran, 2-acetylamino-6- (N-methyl-
p-toluizino) fluoran,

2-amino-6-diethylaminofluorane, 2-amino-6- (di-n-butylamino) fluorane, 2-amino-6- (di-n-amylamino) fluorane, 2-amino-6- (Di-n-hexylamino)
Fluoran, 2-amino-6- (N-cyclohexyl-
N-n-amylamino) fluorane, 2-amino-6-
(N-methylanilino) fluorane, 2-amino-6-
(N-ethylanilino) fluorane, 2-amino-6-
(N-propylanilino) fluorane, 2-amino-6
-(N-methyl-p-toluidino) fluorane, 2-amino-6- (N-ethyl-p-toluidino) fluorane, 2-amino-6- (N-propyl-p-toluidino) fluorane, 2-amino- 6- (N-methyl-p-
Ethylanilino) fluorane, 2-amino-6- (N-
Ethyl-p-ethylanilino) fluorane, 2-amino-6- (N-propyl-p-ethylanilino) fluorane, 2-amino-6- (N-methyl-2,4-dimethylanilino) fluorane, 2-amino- 6- (N-ethyl-2,4-dimethylanilino) fluorane, 2-amino-6- (N-propyl-2,4-dimethylanilino) fluorane, 2-amino-6- (N-methyl-p -Chloranilino) fluorane, 2-amino-6- (N-ethyl-p-chloroanilino) fluorane, 2-amino-6-
(N-propyl-p-chloroanilino) fluorane,
2-Amino-3-methyl-6-diethylaminofluorane, 2-amino-3-methyl-6- (di-n-butylamino) fluorane, 2-amino-3-methyl-6- (di-n-amylamino) ) Fluoran, 2-amino-3-methyl-6- (di-n-hexylamino) fluoran, 2
-Amino-3-methoxy-6- (di-n-butylamino) fluorane, 2-amino-3-methoxy-6- (di-n-amylamino) fluorane, 2-amino-3-methoxy-6- (di -N-hexylamino) fluorane,

1,3-Dimethyl-6-diethylaminofluorane, 1,3-dimethyl-6- (di-n-butylamino) fluorane, 1,3-dimethyl-6- (di-n-)
Amylamino) fluorane, 1,3-dimethyl-6-
(Di-n-hexylamino) fluorane, 1,3-dimethyl-6- (N-cyclohexyl-Nn-butylamino) fluorane, 2,3-dimethyl-6-dimethylaminofluorane, 2-methyl-6 -Dimethylaminofluorane, 2-methyl-6-diethylaminofluorane, 2
-Methyl-6- (di-n-propylamino) fluorane, 2-methyl-6- (di-n-butylamino) fluorane, 2-methyl-6- (di-n-amylamino) fluorane, 2-methyl- 6- (di-n-hexylamino)
Fluoran, 2-methyl-6- (N-cyclohexyl-
N-n-amylamino) fluorane, 2-methyl-6-
(N-cyclohexyl-N-methylamino) fluorane, 3-diethylamino-6- (m-trifluoromethylanilino) fluorane, 3-methyl-6- (N-ethyl-p-toluidino) fluorane, 2-methyl- 6- (N
-Ethyl-p-toluidino) fluorane, 4-methoxy-6- (N-ethyl-p-toluidino) fluorane, 2
-Cyano-6-diethylaminofluorane, 2-cyano-6- (di-n-butylamino) fluorane, 2-cyano-6- (di-n-amylamino) fluorane, 2-cyano-6- (di-n -Hexylamino) fluorane, 2
-Cyano-6- (N-cyclohexyl-Nn-hexylamino) fluorane, 2-cyano-6- (N-cyclohexyl-Nn-decylamino) fluorane.

2-chloro-6-diethylaminofluorane, 2-bromo-6-diethylaminofluorane, 2-
Chlor-6-dipropylaminofluorane, 2-chloro-6-dibutylaminofluorane, 3-chloro-6-cyclohexylaminofluorane, 3-bromo-6-cyclohexylaminofluorane, 2-chloro-6- ( N-
Ethyl-N-isoamylamino) fluorane, 2-chloro-3-methyl-6-diethylaminofluorane, 2-
Anilino-3-chloro-6-diethylaminofluorane, 2- (o-chloroanilino) -3-chloro-6-cyclohexylaminofluorane, 2- (m-trifluoromethylanilino) -3-chloro-6-diethylamino Fluoran, 2- (2,3-dichloroanilino) -3-chloro-6-diethylaminofluorane, 2-ethoxyethylamino-3-chloro-6-dibutylaminofluorane, 2-benzylamino-4-chloro-6 -(N-ethyl-p-toluidino) fluorane, 2-dibenzylamino-4-chloro-6- (N-ethyl-p-toluidino)
Fluoran, 2- (α-phenylethylamino) -4-
Chlor-6-diethylaminofluorane, 2- (N-benzyl-p-trifluoromethylanilino) -4-chloro-6-diethylaminofluorane and the like.

Besides the general formula (11), there are many fluoran compounds preferable as the color former used in the present invention, and specifically, the following compounds are exemplified. 2-anilino-3-
Methyl-6-pyrrolidinofluorane, 2-anilino-3
-Chlor-6-pyrrolidinofluorane, 2-anilino-
3-Methyl-6- (N-ethyl-N-tetrahydrofurfurylamino) fluorane, 2-mesidino-3-methyl-4 ', 5'-benzo-6-diethylaminofluorane, 2- (m-trifluoromethyl) Anilino) -3-methyl-6-pyrrolidinofluorane, 2- (α-naphthylamino) -3,4-benzo-4′-bromo-6- (N-benzyl-N-cyclohexylamino) fluorane, 2 −
Piperidino-6-diethylaminofluorane, 2- (N
-N-propyl-p-trifluoromethylanilino) -6
-Morpholinofluorane, 2- (di-Np-chlorophenyl-methylamino) -6-pyrrolidinofluorane, 2- (Nn-propyl-m-trifluoromethylanilino) -6-morpho Rinofluorane, 3,6-bis (diphenylamino) fluorane, 3,6-bis (di-
p-tolylamino) fluorane, 3,6-bis (di-p)
-Chlorophenylamino) fluorane, 3,6-bis (Np-tolyl-anilino) fluorane, 3,6-bis (Np-chlorophenyl-anilino) fluorane,
3,6-bis (N-biphenyl-anilino) fluorane, 1,2-benzo-6-diethylaminofluorane,
1,2-benzo-6- (N-ethyl-N-isoamylamino) fluorane, 1,2-benzo-6-dibutylaminofluorane, 1,2-benzo-6- (di-n-amylamino) fluorane, 1,2-benzo-6- (di-n-
Hexylamino) fluorane, 1,2-benzo-6-
(N-methyl-N-cyclohexylamino) fluorane, 1,2-benzo-6- (N-ethyl-Nn-octylamino) fluorane, 1,2-benzo-6- (N-
Ethyl-p-toluidino) fluorane, 1,2-benzo-6-diallylaminofluorane, 1,2-benzo-6
-(N-ethoxyethyl-N-ethylamino) fluorane and the like.

There are many compounds other than the fluoran compound which are preferable as the color former used in the present invention, and the following compounds are specifically mentioned. Benzoleucomethylene blue, 2- [3,6-bis (diethylamino)]-6-
(0-chloranilino) xanthyl lactam benzoate,
2- [3,6-bis (diethylamino)]-9- (0-
Chloranilino) xanthyl lactam benzoate, 3,3
-Bis (p-dimethylaminophenyl) -phthalide,
3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) -6-diethylaminophthalide, 3,3-bis (P
-Dimethylaminophenyl) -6-chlorophthalide,
3,3-bis (p-dibutylaminophenyl) phthalide, 3- (2-methoxy-4-dimethylaminophenyl) -3- (2-hydroxy-4,5-dichlorophenyl) phthalide, 3- (2- Hydroxy-4-dimethylaminophenyl) -3- (2-methoxy-5-chlorophenyl) phthalide, 3- (2-hydroxy-4-dimethoxyaminophenyl) -3- (2-methoxy-5-chlorophenyl) phthalide , 3- (2-hydroxy-4-dimethylaminophenyl) -3- (2-methoxy-5-nitrophenyl) phthalide, 3- (2-hydroxy-4-diethylaminophenyl) -3- (2-methoxy-5) -Methylphenyl) phthalide, 3- (2-methoxy-4-dimethylaminophenyl) -3- (2-hydroxy-4-)
Chlor-5-methoxyphenyl) phthalide, 3- (4-
Dimethylamino-2-methoxyphenyl) -3- (1-
Methyl-2-methylindol-3-yl) phthalide,
3- (4-dimethylamino-2-ethoxyphenyl)-
3- (1-methyl-2-methylindol-3-yl)
Phthalide, 3- (4-diethylaminophenyl) -3-
(1-Methyl-2-methylindol-3-yl) phthalide, 3- (4-diethylaminophenyl) -3- (1
-Ethyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-methylphenyl)
-3- (1-methyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-methylphenyl) -3- (1-ethyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2
-Methylphenyl) -3- (1-n-butyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-methyl-2-methylindole- 3-yl) phthalide, 3-
(4-Diethylamino-2-ethoxyphenyl) -3-
(1-Ethyl-2-methylindol-3-yl) phthalide, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-n-butyl-2-methylindole-
3-yl) phthalide, 3- (4-di-n-butylamino-2-ethoxyphenyl) -3- (1-methyl-2-methylindol-3-yl) phthalide, 3- (4-di-
n-Butylamino-2-ethoxyphenyl) -3- (1
-Ethyl-2-methylindol-3-yl) phthalide, 3- (4-di-n-butylamino-2-ethoxyphenyl) -3- (1-n-butyl-2-methylindol-3-yl) Phthalide, 3,6-bis (dimethylamino) fluorene spiro (9,3 ')-6'-dimethylaminophthalide, 6'-chloro-8'-methoxy-benzoindolino-spiropyran, 6'-bromo-2 ′ -Methoxy-benzoindolino-spiropyran and the like.

The above-mentioned color former and developer can be used alone or in combination of two or more. Further, these color developing agent and color developing agent can be used as they are or by being encapsulated in microcapsules. Microencapsulation of the color developer and the color developer may be performed by a known method such as a coacervation method, an interfacial polymerization method, an in situ polymerization method. The reversible thermochromic composition used in the present invention contains the above-mentioned color former and color developer as well as the above-mentioned decolorizer as essential components. Any compound may be used as long as it is a compound that acts on the color image formed in step 1 and can erase the color image in a natural environment. In the present invention, higher alcohols, higher esters and higher amides are used as such decoloring agents. Among the decolorizers used in the present invention, higher alcohols include lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol,
Behenyl alcohol and the like are higher esters such as stearyl myristate, propyl palmitate, ethyl stearate, butyl ethearate, stearyl stearate, glycerin tristearate and propylene glycol distearate, and higher amides such as stearamide. Etc. are particularly preferably used.

The composition ratio of the components constituting the reversible thermochromic composition described above is such that the molar ratio of color former: developing agent: decolorizer is 1.0: 2.0 to 5.0: 0. It is sufficient that the range is 0.1 to 5.0, and if the amount of the developer is too large or too small, the color density will be lowered. Further, as described above, it is possible to control the erasing speed by the kind and amount of the erasing agent, and generally, increasing the addition ratio increases the erasing speed. However, if the amount of the decoloring agent added is too large, the decoloring and the color development may become unstable, so it is desirable that the amount of the decoloring agent added be the minimum necessary amount. Since the optimum composition of the reversible thermochromic composition contained in the recording medium used in the present invention varies depending on the type of material to be used and the use conditions other than the above, each composition is used by trial and error. It is desirable to search for an optimum composition under the conditions and manufacture a recording medium with this composition ratio. In particular, the type and amount of decolorizing agent should be determined in consideration of the time required for proofreading printed matter and the time to store until next use. A thermal recording medium can be produced. The required time and print quality in this case are shown below.

The present inventor investigates the time required for correction of the text and layout of printed-out printed matter, confirmation / correction of typographical errors / missing characters, and the printed matter quality in that case,
Working time is 2 to 5 when using A-4 size paper
The maximum optical density for printing is 0.
A value of 8 or more is preferable, but it has been confirmed that the object can be sufficiently achieved even if it is 0.6 or more. Furthermore, when the used recording medium is reused for the above purpose, it is not always necessary to immediately reuse it, and a plurality of sheets of paper may be prepared and reused after 1 to several days, so that the erasing time is several times. I admitted that it's okay if it is from several hours to several tens of hours. The present invention has been made on the basis of the above-mentioned results of the investigation by the present inventor, and the color-developed image after application of heat is visually recognized for at least 10 minutes, preferably for about 30 minutes to such an extent that the above-mentioned object can be easily achieved. The condition is that it is possible and that it can be reused by spontaneously erasing it after at least a few days. By the way, since the decoloring speed of a color image is higher at higher temperatures, and the relationship between the image density and the decoloring speed is almost linear, the decoloring speed becomes maximum immediately after the application of heat when the image temperature is high and the image density is maximum. As the image density and the image holding temperature decrease, the erasing speed rapidly decreases. Taking these into consideration, in the recording medium of the present invention, the decoloring speed of the image at 25 ° C. is an average value up to 1 hour after the start of color development, and the optical density decreasing speed is 0.10 to 0.50 / 10 minutes, preferably 0. It is good to set it in the range of 20 to 0.30 / 10 minutes.

The reversible thermosensitive recording medium used in the present invention comprises a synthetic paper or a resin film as a support, on which a recording layer containing the reversible thermochromic composition is provided. A binder resin is added to the recording layer in order to form a smooth thin film in which the composition is uniformly dispersed. Also,
In the recording layer, if necessary, various additives, such as a dispersant, a surfactant, and a high molecular weight cationic conductive agent, which are used in ordinary heat-sensitive recording paper, are used for the purpose of improving coating properties or recording properties. Further, a filler, a color image stabilizer, an antioxidant, a light stabilizer, a lubricant and the like can be added to the recording layer. Needless to say, even if the binder resin and the various additives described above are present in the recording layer, the decoloring / coloring behavior of the color forming composition used in the present invention is not affected. The recording layer is formed according to a conventionally known method by uniformly dispersing or dissolving the reversible thermochromic composition, the binder resin and the additives, which are added as necessary, in an organic solvent to support the same. It can be performed by a method of coating and drying on the body. In this case, water can be used as the solvent for the recording layer coating solution,
It was confirmed that the organic solvent is preferable to water in terms of the quality of the product as well as the solubility and coatability. In the recording medium used in the present invention, a resin film or synthetic paper is preferable to paper for the support from the viewpoint of durability. In terms of the decoloring property of the product, there are many problems when the recording layer is directly provided on the paper as the support. The reason for this is that the separation and crystallization of the developer molecule that occurs when the reversible thermosensitive recording medium used in the present invention shifts from the color-developed state to the decolorized state easily penetrates polar compounds such as paper. It is presumed to be disturbed by the support. That is, when the separation of the developer molecules on the paper proceeds, it is considered that the molecules are absorbed and adsorbed by the paper and the growth of crystals becomes difficult.

The binder resin used in the recording layer is preferably one that is resistant to a large number of times of heat application and can well disperse the reversible thermochromic composition, such as polyvinyl chloride, polyvinyl acetate, chloride. Vinyl-vinyl acetate copolymer, polystyrene, styrene copolymer, phenoxy resin, polyester, aromatic polyester, polyurethane, polyvinyl butyral, ethyl cellulose, polyvinyl acetal, polycarbonate, polyacrylic acid ester, polymethacrylic acid ester, acrylic Acid copolymer, maleic acid copolymer, epoxy resin, polyamide, polyvinyl alcohol, chlorinated vinyl chloride resin,
A mixture of these resins is preferred. The organic solvent used for the recording layer forming coating liquid, dibutyl ether,
Ethers such as isopropyl ether, dioxane and tetrahydrofuran; ketones such as acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone and methyl propyl ketone; esters such as ethyl acetate, isopropyl acetate, acetic acid n-propyl and acetic acid n-butyl. Genus; aromatic hydrocarbons such as benzene, toluene, xylene, etc., which are used alone or in combination of two or more.

As described above, in the present invention, heat is applied to the recording medium a number of times, and characters and images are written on the surface with an aqueous pen to correct the formed image. Since the above-mentioned characters and images are wiped off for reuse, it is extremely effective to provide a protective layer on the recording layer. In addition, the protective layer can also have a role of improving chemical resistance, water resistance, abrasion resistance, head matching property, and the like. Further, by adding a polymeric cationic conductive agent to the protective layer, an antistatic function can be imparted, and by containing a light stabilizer, a recording medium having remarkably improved light resistance of images and background can be obtained. In addition, by containing the organic or inorganic filler, a thermal recording medium having high reliability and head matching property can be obtained without causing a problem such as sticking caused by contact with a thermal head or the like. The protective layer of the reversible thermosensitive recording medium used in the present invention is preferably one having large heat resistance as well as abrasion resistance and chemical resistance in order to achieve the above-mentioned object. Can be applied as a coating solution on the recording layer, or can be provided by laminating a heat resistant resin film on the recording layer. The heat resistant curable resin for the protective layer described above includes thermosetting, ultraviolet curable and electron beam curable resins.

As the thermosetting resin, various known resins can be used. Specific examples thereof include bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, o-cresol-novolak type epoxy resin, polyphenol type epoxy resin, polyglycidyl amine type epoxy resin, alcohol type epoxy resin, ester type epoxy resin. Epoxy resin such as;
Xylene-formaldehyde resin; urea resin; melamine resin; benzoguanamine resin; acetoguanamine resin;
Phenol resin; Saturated and unsaturated polyester resins; Furan resins; Fluorine-containing resins such as trifluorochloroethylene copolymer resins, fluoroolefin / vinyl ether copolymer resins; Polyol resins; Amino-modified siloxane resins,
Examples thereof include siloxane resins such as epoxy-modified siloxane resin, alcohol-modified siloxane resin, mercapto-modified siloxane resin, and carboxy-modified siloxane resin.

The curing agent used in the thermosetting resin varies depending on the type of resin, but in the amine type curing agent, ethylenediamine, diethylenetriamine, triethylenetetramine, dimethylaminopropylamine, diethylaminopropylamine, amine glycidyl ether adduct. ,
Hexamethylenetetramine, benzyldimethylamine,
α-methylbenzyldimethylamine, 2,6-di (dimethylaminomethyl) phenol, 2,4,6-tri (dimethylaminomethyl) phenol, pyridine, piperidine, metaphenylenediamine, 4,4′-diaminodiphenylmethane, 4 , 4'-diaminodiphenyl sulfone, 1-cyanoguanidine, boron trifluoride monoethylamine, boron trifluoride ethanol, polyalkylamine and the like are used. In addition, nitrogen-containing curing agents include carboxylic acid amides, benzenesulfonic acid amides, ammonium salts such as ammonium chloride, and amino alcohol hydrochlorides, and organic acid-based curing agents include p-toluenesulfonic acid, oxalic acid, and anhydrous. Phthalic acid, maleic anhydride, hexahydrophthalic anhydride, pyromellitic anhydride, trimellitic anhydride, chlorendic anhydride, methyl phthalate-maleic acid adduct and the like are used.

As the organic polyisocyanate type curing agent, tolylene-2,4-diisocyanate, 4-methoxy-1,3-phenylene diisocyanate, 4-isopropyl-1,3-phenylene diisocyanate, 2,
4-diisocyanate diphenyl ether, 4,4'-
Methylenebis (phenylisocyanate), durylylene diisocyanate, 1,5-naphthalene diisocyanate, benzidine diisocyanate, o-nitrobenzidine diisocyanate, 4,4′-diisocyanate dibenzyl, 1,4-tetramethylene diisocyanate,
1,6-hexamethylene diisocyanate, 1,10-
Decamethylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate,
4,4'-methylenebis (cyclohexyl isocyanate), 1,5-tetrahydronaphthalene diisocyanate and the like can be mentioned. Furthermore, adducts of these organic polyisocyanates with other compounds, for example, those having the following structural formulas [A] to [C] can be mentioned, but not limited thereto.

[0045]

[Chemical 4]

[Chemical 5]

[0046]

[Chemical 6] In addition to the above, peroxides such as dialkyl peroxides, peroxyketals, diacyl peroxides, hydroperoxides, peroxyesters and ketone peroxides are also used as curing agents for thermosetting resins used in the protective layer. These thermosetting resins and curing agents may be used alone or in admixture of two or more, but it is important to select a curing agent suitable for the resin used.

The type of the UV curable resin is not limited, and various conventionally known resins can be used. As the solvent for this resin, organic solvents such as tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, isopropyl alcohol, ethyl acetate, butyl acetate, toluene and benzene are preferably used. Further, instead of these solvents, a liquid photopolymerizable monomer can be used as a reactive diluent for easy handling. Liquid photopolymerizable monomers include 2-ethylhexyl acrylate, cyclohexyl acrylate, butoxyethyl acrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol. Examples thereof include triacrylate and ethyl methacrylate.

The electron beam curable resin used for forming the protective layer may be any monomer or oligomer (or prepolymer) that undergoes a polymerization reaction upon irradiation with an electron beam and is cured into a resin. Such monomers or oligomers
(Poly) ester acrylate, (poly) urethane acrylate, epoxy acrylate, polybutadiene acrylate, silicone acrylate, melamine acrylate, polyphosphazene methacrylate and the like. (Poly)
Ester acrylates are 1,6-hexanediol, propylene glycol (as polypropylene oxide), polyhydric alcohols such as diethylene glycol and adipic acid,
A polybasic acid such as phthalic anhydride or trimellitic acid is reacted with acrylic acid. An example of the structure is (a) to (c)
Shown in.

(A) Adipic acid / 1,6-hexanediol / acrylic acid

[Chemical 7] (B) Phthalic anhydride / polypropylene oxide / acrylic acid

[Chemical 8] (C) Trimet acid / diethylene glycol / acrylic acid

[Chemical 9]

The (poly) urethane acrylate is obtained by reacting a compound having an isocyanate group such as tolylene diisocyanate (TDI) with an acrylate having a hydroxyl group. An example of the structure is shown in (d). HEA is 2-hydroxyethyl acrylate, HD
O is an abbreviation for 1,6-hexanediol and ADA is an abbreviation for adipic acid. (D) HEA / TDI / HDO / ADA / HDO / TD
I / HEA

[Chemical 10]

Epoxy acrylates are roughly classified into bisphenol A type, novolac type and alicyclic type, and the epoxy groups of these epoxy resins are esterified with acrylic acid to make a functional group an acryloyl group.
Examples of the structure are shown in (e) to (g). (E) Bisphenol A-epichlorohydrin type / acrylic acid

[Chemical 11] (F) Phenol novolac-epichlorohydrin type /
Acrylic acid

[Chemical 12] (G) Alicyclic / acrylic acid

[Chemical 13]

Polybutadiene acrylate has a terminal OH
Isocyanate or 1,2 in group-containing 1,2 polybutadiene
-Mercaptoethanol or the like is reacted, and then acrylic acid or the like is further reacted. Its structural example (h)
Shown in. (H)

[Chemical 14] Silicone acrylate is, for example, methacryl-modified by a condensation reaction (demethanol reaction) between an organofunctional trimethoxysilane and a silanol group-containing polysiloxane, and a structural example thereof is shown in (i). (I)

[Chemical 15]

The protective layer provided in the recording medium used in the present invention can be used after curing a water-soluble polymer or a polymer aqueous emulsion. The water-soluble polymer or aqueous emulsion used in this case is not particularly limited, and various conventionally known ones may be used. For example, as the water-soluble polymer, polyvinyl alcohol, modified polyvinyl alcohol,
Starch and its derivatives, cellulose derivatives such as methyl cellulose, methoxy cellulose and hydroxyethyl cellulose, casein, gelatin, polyvinylpyrrolidone, styrene-maleic anhydride copolymer, polyacrylamide, modified polyacrylamide, methyl vinyl ether-maleic anhydride copolymer. , Carboxy-modified polyethylene, diisobutylene-maleic anhydride copolymer, polyvinyl alcohol-acrylamide block copolymer,
Melamine-formaldehyde resin, urea-formaldehyde resin and the like are used. As an aqueous emulsion,
Polyvinyl acetate, polyurethane, styrene-butadiene copolymer, styrene-butadiene-acrylic terpolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride-vinyl acetate copolymer, polybutyl methacrylate, ethylene-acetic acid It is preferable to use a resin such as a vinyl copolymer. These are used alone or in combination of two or more, and an appropriate curing agent is added.

As described above, in the recording medium used in the present invention, the heat-resistant film may be laminated on the recording layer to form the protective layer. The protective layer thus formed has high heat resistance and strength that cannot be obtained by conventional methods such as coating method. A film made of fluorine resin or polyimide resin is suitable. Of these, as the fluororesin,
Tetrafluoroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetra-added ethylene-ethylene copolymer resin, trifluorochloroethylene Resin, vinylidene fluoride resin, vinyl fluoride resin, trifluorochloroethylene-ethylene copolymer resin, fluorine-containing polybenzoxazole resin and the like are used, and various polyimide-based resins, polyamide-imide, polyparabanic acid, Polyetherimide is used. In addition, films of polyamide, polyether ether ketone, aromatic polyester, polyphenyl sulfide, polysulfone, etc. can be used for the protective layer. When these films are used as the protective layer, the film thickness is 2 in view of the thermal sensitivity and economical efficiency of the reversible thermosensitive recording medium.
It is desirable to use those having a thickness of 5 μm or less.

As the laminating method for forming the protective layer, a dry laminating method is preferable, and the adhesive may be one generally used in the dry laminating method. Specific examples of the resin used for the adhesive include thermoplastic resins such as ionomer resins, acrylic resins (including aqueous emulsions), modified ethylene-vinyl acetate copolymer resins, butadiene resins, phenoxy resins, polyvinyl ethers, There are polyvinyl formal, vinyl acetate resin, polyester resin and the like. Further, as the thermosetting resin, polyurethane (including emulsion), various epoxy resins, xylene-formaldehyde resin, urea resin, melamine resin, benzoguanamine resin, acetoguanamine resin, phenol resin, saturated or unsaturated polyester resin, furan resin, There are polyol resins and the like. As the curing agent used for curing the thermosetting resin, known amine-based, phenol-based, organic acid and anhydride-based curing agents may be used, but a curing agent suitable for the resin used It is important to choose.

An image is formed on the recording medium used in the present invention by a hot pen, a thermal head,
Although not particularly limited, such as laser heating, a thermal head is generally used in consideration of the object of the present invention. In the present invention, after being printed on a recording medium, a writing instrument that adds to a printed matter for the purpose of confirming or correcting a manuscript is easy to evaluate from various aspects regarding performance maintenance and working environment during repeated use. It was confirmed that it is preferable to use a water-based pen that can be wiped off with a good film writing property. As the aqueous pen in this case, an aqueous pen containing a surfactant can be used, but an aqueous pen containing a boron polymer is particularly preferable. With this water-based pen, there is no phenomenon that the retouched image bleeds or repels ink when used, and since the retouched image formed on the film surface can be easily wiped off, there is little deterioration in the performance of the recording medium, improving workability. It is also extremely useful from the viewpoint of both improving the durability of the recording medium.

[0057]

EXAMPLES The present invention will now be described more specifically by way of examples, but the present invention is not limited to these examples. All parts shown below are based on weight. The image densities in the examples and the comparative examples were measured with a Macbeth RD-914 type densitometer.

Example 1 [Recording Layer] The following composition was used to make a particle size of 1 to 4 μm with a ball mill.
Was pulverized and dispersed to prepare a coating liquid for forming a recording layer. 2- (o-chloroanilino) -6-dibutylaminofluorane 3.5 parts Hexadecylphosphonic acid 10 parts Ethylcellulose (manufactured by Kanto Chemical Co., Inc.) 6 parts Stearyl alkole 2 parts Methylethylketone 44 parts Toluene 50 parts Prepared as described above. Apply the coating solution on a polyester film with a thickness of 100 μm with a wire bar to a thickness of about 5 μm.
A reversible thermosensitive recording medium was obtained by coating and drying so that [Protective Layer] A melamine-formalin prepolymer (Milven SM-8 manufactured by Showa High Polymer Co., Ltd.) is formed on the recording layer of the recording medium.
00) was applied with a wire bar to a coating thickness of about 2 μm and dried at 120 ° C. to prepare a reversible thermosensitive recording medium. The reversible thermosensitive recording medium produced as described above was used, and using the MyRiport NL3Hi word processor manufactured by Ricoh Co., Ltd., when printed with a thermal head, a clear printed matter with a black print density of 1.21 was obtained. Was obtained. This printed material had a print density of 1. after 10 minutes.
Although it decreased to 00, there was no problem in reading the characters. Next, when an attempt was made to add or correct a print formed with a water-based ink in which a charge transfer type boron polymer was added to the above-mentioned printed matter, the addability to the surface of the recording medium by the ink was extremely excellent. It was easy to wipe with a cloth. In addition, the recording medium after being used in this embodiment is
After 10 hours from color development, the print disappeared and returned to the state before use, and repeated use was repeated 10 times, but no functional deterioration was observed.

Example 2 [Recording Layer] Using the following composition, a coating liquid for forming a recording layer was prepared in the same manner as in Example 1. 2-anilino-3-methyl-6- (N-ethyl 3.3 parts-p-toluidino) fluorane eicosyl thiomalic acid 10 parts vinyl chloride-vinyl acetate copolymer (VYHH, 10 parts Union Carbide) Stearic acid amide 3 parts Methyl ethyl ketone 45 parts Toluene 45 parts The coating solution prepared as described above is coated on a synthetic paper having a thickness of 100 μm with a wire bar to a coating thickness of about 4 μm and dried to form a reversible thermosensitive recording medium. It was made. [Protective Layer] A mixture having the following composition was uniformly dispersed to prepare a coating liquid for forming a protective layer. Polyester polyacrylate and polyurethane polyacrylate 100 parts of each prepolymer mixture (78E204 manufactured by Mobil Oil Co., Ltd.) True spherical monodisperse silicone resin fine powder (TOSPAR 120 manufactured by Toshiba Silicone Co., Ltd.) 1 part A protective layer on the recording layer of the above recording medium. The coating solution for forming is applied with a wire bar, heated and dried, and then cured with an irradiation dose of 3 Mrad using an electron curtain type electron beam irradiation device (CB: 150 manufactured by ESI) to form a protective layer having a thickness of about 4 μm. The provided reversible thermosensitive recording medium was produced. Using this reversible thermosensitive recording medium, printing was performed with a word processor (My Report NL-1 manufactured by Ricoh) in the same manner as in Example 1. As a result, a clear printed matter having a black print density of 1.23 was obtained. The print density of this printed matter is 1.01 after 10 minutes.
However, there was no problem in reading the characters. Next, the same writability and erasability test as in Example 1 was tried on the printed matter, and the same results as in Example 1 were obtained.
The color erasing speed of the color image and the restoring ability of the recording medium were almost the same as those in Example 1, and the print erasing ability was completely the same as in Example 1.

Example 3 [Recording Layer] Using the following composition, a coating liquid for forming a recording layer was prepared in the same manner as in Example 1. 2-anilino-3-methyl-6- (N-ethyl 3.3 parts-p-toluidino) fluorane octadecylmalonic acid 10 parts Vinyl chloride-vinyl acetate copolymer (VYHH, 10 parts Union Carbide) stearic acid Butyl 4 parts Tetrahydrofuran 90 parts The coating liquid prepared as described above was applied to a white polyester film having a thickness of 100 μm with a wire bar so as to have a coating thickness of about 4.5 μm and dried to prepare a reversible thermosensitive recording medium. . [Protective Layer] A mixture having the following composition was sufficiently pulverized and dispersed by a ball mill to prepare a coating liquid for forming a protective layer. 75% of urethane acrylate UV curable resin 100 parts Butyl acetate solution (Dainippon Ink and Chemicals, Unidick C7-157) Alumina sol (100-200 μm) 3 parts Stearic acid amide 3 parts Butyl acetate 50 parts Of the above recording medium A coating solution for forming a protective layer was applied onto the recording layer with a wire bar, heated and dried, and then cured with a UV lamp of 80 W / cm to prepare a reversible thermosensitive recording medium provided with a protective layer having a thickness of about 3 μm. Using this reversible thermosensitive recording medium, a word processor (Ricoh's My Report NL
-1) When printed with black, the print density is 1.1.
A clear printed matter of 8 was obtained. The print density of the printed matter decreased to 0.71 after 10 minutes, but there was no problem in reading the characters. Next, the same writability and erasability test as in Example 1 was tried on the printed matter, and the same results as in Example 1 were obtained. When this printed matter was left at room temperature for 6 hours, the color image spontaneously disappeared and the state before use was restored. Such repeated test was performed 10 times, but almost no deterioration in function was observed.

Example 4 A reversible thermosensitive recording medium was prepared in the same manner as in Example 1 except that the following composition was used. 2- (o-chloroanilino) -6-diethylaminofluorane 3.5 parts α-hydroxyhexadecanoic acid 10 parts polyacrylic ester 10 parts (Dianal BR-102, manufactured by Mitsubishi Rayon Co., Ltd.) myristyl alcohol 2 parts methyl ethyl ketone (MEK) 45 parts Toluene 45 parts The coating liquid prepared as described above was applied to a synthetic paper having a thickness of 100 μm with a wire bar so as to have a coating thickness of about 4 μm and dried to prepare a reversible thermosensitive recording medium. The thickness of the reversible thermosensitive recording medium coated with an adhesive was 4 on the recording layer.
Aromatic polyamide film of μm is attached and pressure is 2
A reversible thermosensitive recording medium provided with a heat resistant film layer was prepared by pressure bonding with a 130 ° C. heat roll of kg / cm ² . As the adhesive, Byron 300 (saturated polyester) manufactured by Toyobo Co., Ltd. was used, which was dissolved in a toluene-MEK mixed solution and applied to the polyamide film so that the dry adhesion amount was 3 g / m ² . After drying, it was attached to the recording layer. Using this reversible thermosensitive recording medium, a word processor (My Report NL-3 manufactured by Ricoh Co., Ltd.) was used as in Example 1.
When printed with Hi), a clear and good-contrast printed matter on which a black image having a print density of 1.20 was printed was obtained.
The print density decreased to 1.01 after 10 minutes, but there was no problem in reading the characters. The printed matter was examined for the addition / correction function and repeatability in the same manner as in Example 1. As a result, the same results as in Example 1 were obtained, and no particular problem was found in the function. The erasing time of this recording medium at room temperature was 10 hours.

Example 5 Using the following composition, a coating liquid for forming a recording layer was prepared in the same manner as in Example 1. 1,2-benzo-6- (N-ethyl-N-isoamyl 3.3 parts amino) fluorane p-octadecyl thiophenol 10 parts vinyl chloride-vinyl acetate copolymer (VYHH, 10 parts Union Carbide) glycerin Tristearate 3 parts Methyl ethyl ketone 45 parts Toluene 45 parts The coating solution prepared as above is applied to a white polyester film having a thickness of 100 μm with a wire bar to a thickness of about 4
A reversible thermosensitive recording medium was prepared by coating and drying so that the thickness became μm. Onto the recording layer of this reversible thermosensitive recording medium, a 6 μm thick vinylidene fluoride resin film coated with an adhesive is stuck, then pressure-bonded with a roll having a pressure of 2 kg / cm ² , and further dried at 130 ° C. for 10 minutes. Then, a reversible thermosensitive recording medium provided with a heat resistant film layer was produced. A urethane emulsion (trade name: Teisan Urethane SL-1760) is used as the adhesive, and the dry adhesion amount is 4 g /
The vinylidene fluoride resin film was applied so as to have a size of m ^2, and pressure-bonded onto the recording layer. Using this reversible thermosensitive recording medium, when printing was performed with a word processor (My Report NL3Hi manufactured by Ricoh) in the same manner as in Example 1, a red image with a print density of 1.00 was clearly printed on a white background. The printed matter had a print density of 0.80 after 10 minutes, but there was no problem in reading the characters. With respect to the recording medium, the addition / correction function and repeatability were examined in the same manner as in Example 1. As a result, almost the same results as in Example 1 were obtained including the erasing time.

Comparative Example 1 A thermosensitive recording medium was prepared in the same manner as in Example 1 except that stearyl alcohol was not added to the recording layer forming coating solution of Example 1, and the same evaluation test as in Example 1 was conducted on the recording medium. When this recording medium was used, a color-developed image as clear as in Example 1 was obtained, but the image did not disappear even when left at room temperature for 10 days or longer, and did not exhibit the characteristics of the present invention. .

Comparative Example 2 The hexadecylphosphonic acid of Example 1 was replaced with 2,2-bis (p
A thermosensitive recording medium was prepared in the same manner as in Example 1 except that -hydroxyphenyl) propane was used, and the same evaluation test as in Example 1 was conducted on the recording medium. Although a similar black image was obtained, this image showed a tendency to be erased by heating, but it was not erased even when left at room temperature for 10 days or more.

[0065]

INDUSTRIAL APPLICABILITY The reversible thermosensitive recording medium used in the present invention is suitable as a recording medium for printing out sentences, drawings and the like input to a printing system such as a word processor with a thermal printer. The printed matter printed on the recording medium can be easily corrected with a water-based pen or the like. Therefore, the printed matter printed out on the recording medium used in the present invention can be sufficiently proofread, and the portion added for proofreading can be easily wiped off and the portion developed by heat can be easily removed. Since the recording medium is naturally erased, the recording medium can be repeatedly used without requiring specific equipment, consumables, or energy. For this reason, the amount of recording paper wasted for proofreading and the like at the time of document creation is significantly reduced, which can contribute to a reduction in dust discharge and resource saving.

Claims (2)

[Claims] 1. A reversible thermochromic composition containing an electron-donating color-developing organic compound and an electron-accepting compound, wherein the composition in a colored state is changed to a decolored state without heating. A reversible thermosensitive recording medium having a recording layer containing a composition containing a decoloring agent capable of forming a color reversible recording medium is used to form a color recording state by heat application, and a color recording state obtained in the step. A method for repeatedly forming an image, characterized in that the erasing step of erasing the recording medium in the natural environment is repeated. 2. The decolorizer is selected from the group consisting of higher alcohols, higher esters and higher amides.
It is a kind or a mixture of two or more kinds.
The method of repeatedly forming images.