JP3468565B2 - Reversible thermosensitive recording material and reversible thermosensitive recording medium - Google Patents

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 reversibly repeating recording and erasing by thermal means and maintaining a recorded state even in an environment of room temperature to 80 ° C. The present invention relates to a reversible thermosensitive recording medium used.

[0002]

2. Description of the Related Art A reversible thermosensitive recording material has a characteristic that the transparency of the material (here, the transparency with respect to visible light will be discussed. The same applies hereinafter) is changed by thermal history. Therefore, by a thermal means such as a thermal head,
It is possible to make a display or the like by making the heat history of a predetermined portion of the material different from that of other portions and making the transparency of both portions different.

As a conventional example of such a reversible thermosensitive recording material, there is one disclosed in, for example, JP-A-55-154198. In the reversible thermosensitive recording material disclosed in this publication, behenic acid (docosanoic acid) is added to a matrix material composed of a polymer such as polyester or a resin.
It was composed by dispersing organic low molecular weight substances such as. In this publication, the following examples are described in detail.

A reversible thermosensitive recording material containing a high molecular weight linear copolyester based on an aromatic dicarboxylic acid and an aliphatic diol and docosanoic acid shows stable transparency when heated to 72 ° C. and cooled. It was This is 77 ℃
It was possible to return to the opaque state only by reheating to the above temperature.

A reversible thermosensitive recording material containing a copolymer of vinylidene chloride and acrylonitrilo, docosanoic acid and a fluorad lubricant for improving fluidity is 63
When it was heated to ℃ and cooled, it showed stable transparency.
It could only be returned to the opaque state by reheating to a temperature above 74 ° C.

A reversible thermosensitive recording material containing a copolymer of vinyl chloride and vinyl acetate and docosanol is 6
When heated to 8 ° C. and cooled, it showed stable transparency. It could only be returned to the opaque state by reheating to temperatures above 70 ° C.

A reversible thermosensitive recording material containing polyester and docosanoic acid shows stable transparency when heated to 72 ° C. and cooled. It could only be returned to the opaque state by reheating to a temperature above 77 ° C.

By the way, such a reversible thermosensitive recording material can be used as a reversible thermosensitive recording medium by forming a film on a suitable support, and can be used as a display medium. For example, it is used as a prepaid card such as a telephone card, an orange card, a highway card, a destination display label for products or parts, and a signboard.

[0009]

However, in the conventional reversible thermosensitive recording materials, the temperature at which the cloudy state changes to the transparent state is 72 ° C in the above case, 63 ° C in the case of The maximum temperature was 72 ° C, such as 68 ° C for the one and 72 ° C for the one. Therefore, when a temperature of 72 ° C. is selectively applied to a prepaid card made of a conventional reversible thermosensitive recording material to selectively form a transparent portion (for example, characters) and then the transparent portion is left in the vehicle, etc. When the temperature is lower than 72 ° C, the transparent portion (characters) is preserved, but when the temperature inside the vehicle exceeds 72 ° C, there is a problem that the entire prepaid card becomes transparent and the characters disappear. Such a problem similarly occurs when the display is performed by utilizing the change from the transparent state to the cloudy state. The temperature there is often 70 to 80 [deg.] C. outdoors in the midsummer or in a car, and therefore it is desired to solve the above problems.

Further, in the conventional reversible thermosensitive recording material, the transmittance ratio (contrast) in each of the transparent state and the opaque state is not so large, so that further improvement has been desired.

[0011]

Therefore, according to the reversible thermosensitive recording material of the first invention of this application, in the reversible thermosensitive recording material containing a matrix material and an organic low molecular weight substance, the transparency of which changes depending on thermal history, The organic low molecular weight substance is selected from the group of saturated carboxylic acids having carbon numbers in the range of 27 to 61 and derivatives thereof, and contains at least three kinds of hentriacontanoic acid, nonacosanoic acid and tritriacontanoic acid as main components. It is characterized by including. In carrying out the present invention, in addition to at least three types of organic low molecular weight substances, monocarboxylic acids having 10 to 26 carbon atoms, dicarboxylic acids having 10 to 26 carbon atoms, and 10 to 61 carbon atoms are further used. The composition may include one or more selected from the derivatives of monocarboxylic acids and the derivatives of dicarboxylic acids having 10 to 61 carbon atoms. However, even in this case, it is selected from a saturated carboxylic acid having a carbon number of 27 to 61 and its derivative group, and at least three kinds of Hentriacontanoic acid, Nonacosanoic acid and Tritriacontanoic acid are mainly used. It is preferable to mainly use the organic low molecular weight substance contained as a component. As the organic low-molecular substance, the main component is 3 kinds of Hentriacontanoic acid, Nonacosanoic acid and Tritriacontanoic acid,
For example, the content of Hentriacontanoic acid is 18 mol%,
When the content of nonacosanoic acid is 13 mol% and the content of tritriacontanoic acid is 15 mol% (see S1 in Examples described later), the content of the above three kinds is 20 mol%,
16 mol% and 16 mol% (S in Examples described later
It has been confirmed by experiments that (2) is suitable for achieving the object of the present invention.

In the first invention, the upper limit of the carbon number of the saturated carboxylic acid and its derivative used as the organic low molecular weight substance is set to 61 mainly because of easy availability and the like. More than 10 can also be used.

Here, the mixing ratio of the matrix material and the organic low-molecular weight material is 1: 1 by weight of the organic low-molecular weight material.
When it is contained in excess of 2, it becomes difficult to form a film of the reversible thermosensitive recording material, and when it is less than 20: 1, the heat reversibility becomes small.

In addition to the inclusion of the matrix material and the organic low-molecular-weight substance as used herein, not only in the case of containing them, but also in addition to these, substances that improve the film quality of the reversible thermosensitive recording material, and lubrication. It is also meant to include other substances such as substances that improve the properties.

In the actual use of the reversible thermosensitive recording material, the coating solution of the reversible thermosensitive recording material may be adjusted in order to adhere it to a substrate or the like. In that case, it is preferable to dissolve the matrix material and the organic low molecular weight substance in a solvent to obtain a coating solution. The solvent may be, but is not limited to, one selected from tetrahydrofuran, methyl ethyl ketone, methyl isobutyl ketone, chloroform, carbon tetrachloride, ethanol, toluene and benzene, or two kinds. It is better to use a mixture of the above. The coating solution may be heated and used if necessary.

According to the second invention of this application, in a reversible thermosensitive recording medium comprising a support and a reversible thermosensitive recording layer, the reversible thermosensitive recording layer is the reversible thermosensitive recording material of the first invention. It is characterized in that it is configured with.

[0017]

In these first and second inventions, the matrix material can be composed of any suitable material. Specific examples of the matrix material include, but are not limited to, polyvinyl acetals, or polyvinyl acetals and epoxy compounds, polyvinyl acetals and phenol compounds, polyvinyl acetals and aldehyde compounds, polyvinyl acetals such as polyvinyl acetals and isocyanate compounds. Compound with other resin, or vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer, vinyl chloride-vinyl acetate-maleic acid copolymer, vinyl chloride-acrylate Examples thereof include copolymers, polyvinylidene chloride, vinylidene chloride-vinyl chloride copolymers, vinylidene chloride-acrylonitrile copolymers, and polyesters.

The saturated carboxylic acid having a carbon number of 27 to 61 is not limited to the following, in addition to hentriacontanoic acid, nonacosanoic acid and tritriacontanoic acid, for example, as described below. Those listed in Table 1, namely, heptacosanoic acid, montanic acid, melissic acid, laxeric acid, gedic acid, ceroplastic acid, hexatriacontanoic acid, heptatriacontanoic acid, octatriacontanoic acid, nonatriacontanoic acid, tetracontane Acid, hentetracontanoic acid, dotetracontanoic acid, tritetracontanoic acid, tetratetracontanoic acid, pentatetracontanoic acid, hexatetracontanoic acid, heptatetracontanoic acid, octatetracontanoic acid, nonatetracontanoic acid, pentacontanoic acid , Hempentacontanoic acid, dopentacontanoic acid, Pentacontanoic acid, tetrapentaerythritol proximal acid, penta penta proximal acid, hexa penta proximal acid, hepta penta proximal acid, octa penta proximal acid, nona penta proximal acid, Hekisakontan acid, can be cited Dohekisakontan acid.

Specific examples of the monocarboxylic acid having 10 to 26 carbon atoms include, but are not limited to, capric acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid and palmitic acid. , Heptadecanoic acid, stearic acid, nonadecanoic acid, arachidic acid, heneicosanoic acid, behenic acid, tricosanoic acid, lignoceric acid, pentacosanoic acid, cerotic acid, decenoic acid, undecenoic acid, dodecenoic acid, tridecenoic acid, tetradecenoic acid, pentadecenoic acid, hexadecene acid Acid, heptadecenoic acid, octadecenoic acid, nonadecenoic acid, eicosenoic acid, heneicosenoic acid, docosenoic acid, tricosenoic acid, tetracosenoic acid,
Examples thereof include pentacosenoic acid and hexacosenoic acid.

Specific examples of the dicarboxylic acid having 10 to 26 carbon atoms include, but are not limited to, decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid and pentadecanedioic acid. , Hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, nonadecanedioic acid,
Eicosane diacid, hene eicosane diacid, docosandioic acid,
Tricosanedioic acid, tetracosanedioic acid, pentacosanedioic acid, hexacosanedioic acid, decenedioic acid, undecenedioic acid,
Dodecenedioic acid, tridecenedioic acid, tetradecenedioic acid, pentadecenedioic acid, hexadecenedioic acid, heptadecenedioic acid, octadecenedioic acid, nonadecenedioic acid, eicosendioic acid, heneicosenedioic acid, docosenedioic acid, tricosenedioic acid, tetracosenedioic acid. Examples thereof include acids, pentacosenedioic acid and hexacosenedioic acid.

Derivatives of monocarboxylic acids having 10 to 61 carbon atoms are not limited to the following, but include decanoic acid amide, undecanoic acid amide, dodecanoic acid amide, tridecanoic acid amide, tetradecanoic acid amide, and pentadecanoic acid amide. , Hexadecanoic acid amide, heptadecanoic acid amide,
Octadecanoic acid amide, nonadecanoic acid amide, eicosanoic acid amide, heneicosanoic acid amide, docosanoic acid amide, tricosanoic acid amide, tetracosanoic acid amide, pentacosanoic acid amide, hexacosanoic acid amide, heptacosanoic acid amide, octacosanoic acid amide, nonacosanoic acid amide, triacontane Acid amide, hentriacontanoic acid amide, dotriacontanoic acid amide, tritriacontanoic acid amide, tetratriacontanoic acid amide, pentatriacontanoic acid amide, hexatriacontanoic acid amide,
Heptatriacontanoic acid amide, Nonatriacontanoic acid amide, Tetracontanic acid amide, Hentetracontanic acid amide, Dotetracontanic acid amide, Tritetraacontanic acid amide, Tetratetracontanic acid amide, Pentatetracontanic acid amide, Hexatetra Contanic acid amide, heptatetracontanic acid amide, octatetracontanic acid amide, nonatetracontanic acid amide, pentacontanic acid amide, hempentacontanic acid amide, dopentacontanic acid amide, tripentacontanic acid amide,
Tetrapentacontanic acid amide, pentapentacontanic acid amide, hexapentacontanic acid amide, heptapentacontanic acid amide, octapentacontanic acid amide,
Nonapentacontanic acid amide, hexacontanic acid amide, dohexacontanic acid amide, decenoic acid amide, undecenoic acid amide, dodecenoic acid amide, tridecenoic acid amide, tetradecenoic acid amide, pentadecenoic acid amide, hexadecenoic acid amide, heptadecenoic acid amide, octadecene amide Acid amides, nonadecenoic acid amides, eicosenoic acid amides, heneicosenoic acid amides, docosenoic acid amides, tricosenoic acid amides, tetracosenoic acid amides, pentacosenoic acid amides, hexacosenoic acid amides, heptacosenoic acid amides, amides of octacosenoic acid amides, nonacosenoic amides, Amine decanoate, amine undecanoate, amine dodecanoate, amine tridecanoate, amine tetradecanoate, amine pentadecanoate, amine hexadecanoate, amine heptadecanoate, Amine cutadecanoate, amine nonadecanoate, amine eicosanoate, amine heneicosanoate, amine docosanoate, amine tricosanoate, amine tetracosanoate, amine pentacosanoate, amine hexacosanoate, amine heptacosanoate, amine octacosanoate, amine nonacosanoate, triacontane Acid amine, hentriacontanoic acid amine, dotriacontanoic acid amine, tritriacontanoic acid amine, tetratriacontanoic acid amine, pentatriacontanoic acid amine, hexatriacontanoic acid amine, heptatriacontanoic acid amine, nonatriacontanoic acid amine , Amine tetracontanoate, amine henntetracontanoate, amine dotetracontanoate, amine tritetraacontanoate, amine tetratetracontanoate, pentatetracontane Amine,
Hexatetracontanoic acid amine, heptatetracontanoic acid amine, octatetracontanoic acid amine, nonatetracontanoic acid amine, pentapentanoic acid amine, hempentacontanoic acid amine, dopentacontanoic acid amine, tripentacontanoic acid amine, tetrapentacontane Acid amine, pentapentacontanoic acid amine, hexapentacontanoic acid amine, heptapentacontanoic acid amine, octapentacontanoic acid amine, nonapentacontanoic acid amine, hexacontanoic acid amine, dohexacontanoic acid amine, decenoic acid amine, undecenoic acid Amine, amine dodecenoate, amine tridecenoate, amine tetradecenoate,
Pentadecenoic acid amine, hexadecenoic acid amine, heptadecenoic acid amine, octadecenoic acid amine, nonadecenoic acid amine, eicosenoic acid amine, heneicosenoic acid amine, docosenoic acid amine, tricosenoic acid amine, tetracosenoic acid amine, pentacosenoic acid amine, hexacosenoic acid amine, heptacosenoic acid Amines, amines such as octacocenoic acid amine, nonacocholic acid amine, decanoic acid anilide, undecanoic acid anilide, dodecanoic acid anilide, tridecanoic acid anilide, tetradecanoic acid anilide, pentadecanoic acid anilide, hexadecanoic acid anilide, heptadecanoic acid anilide, octadecanoic acid anilide, nonadecane Acid anilide, eicosanoic acid anilide, heneicosanoic acid anilide, docosanoic acid anilide, tricosanoic acid anilide,
Tetracosanoic acid anilide, pentacosanoic acid anilide, hexacosanoic acid anilide, heptacosanoic acid anilide, octacosanoic acid anilide, nonacosanoic acid anilide, triacontanic acid anilide, hentriacontanic acid anilide, dotriacontanoic acid anilide, tritriacontanic acid anilide, tetratriacontane Acid anilide, pentatriacontanoic acid anilide, hexatriacontanoic acid anilide, heptatriacontanoic acid anilide, nonatriacontanoic acid anilide, tetracontanoic acid anilide, hentetracontanic acid anilide, dotetracontanoic acid anilide,
Tritetraacontanoic acid anilide, tetratetracontanic acid anilide, pentatetracontanic acid anilide, hexatetracontanic acid anilide, heptatetracontanic acid anilide, octatetracontanic acid anilide, nonatetracontanic acid anilide, pentacontanic acid anilide, hempentaconic acid Tanilic acid anilide, dopentacontanic acid anilide, tripentacontanic acid anilide, tetrapentacontanic acid anilide, pentapentacontanic acid anilide,
Hexapentacontanoic acid anilide, heptapentacontanoic acid anilide, octapentacontanoic acid anilide, nonapentacontanoic acid anilide, hexacontanoic acid anilide, dohexacontanoic acid anilide, decenoic acid anilide,
Undecenoic acid anilide, dodecenoic acid anilide, tridecenoic acid anilide, tetradecenoic acid anilide, pentadecenoic acid anilide, hexadecenoic acid anilide, heptadecenoic acid anilide, octadecenoic acid anilide, nonadecenoic acid anilide, eicosenoic acid anilide, heneicosenoic acid anilide, docosenoic acid anilide, docosenoic acid anilide Anilides such as anilide, tetracosenoic acid anilide, pentacosenoic acid anilide, hexacosenoic acid anilide, heptacosenoic acid anilide, octacosenoic acid anilide, and nonacosenoic acid anilide.
Decanol, undecanol, dodecanol, tridecanol, tetradecanol, pentadecanol, hexadecanol, heptadecanol, octadecanol, nonadecanol, eicosanol, heneicosanol,
Docosanol, tricosanol, tetracosanol, pentacosanol, hexacosanol, heptacosanol, octacosanol, nonacosanol, triacontanol, hentriacontanol, dotriacontanol, tritriacontanol, tetratriacontanol, pentatriacontanol, hexa Triacontanol, heptatriacontanol, nonatriacontanol, tetracontanol, hemtetracontanol,
Dotetracontanol, tritetraacontanol, tetratetracontanol, pentatetracontanol,
Hexatetracontanol, heptatetracontanol, octatetracontanol, nonatetracontanol, pentacontanol, hempentacontanol, dopentacontanol, tripentacontanol, tetrapentacontanol, pentapentacontanol, hexapentacontanol, heptapentacontanol, Octapentacontanol, Nonapentacontanol, Hexacontanol, Dohexacontanol, Decenol, Undecenol, Dodecenol, Tridecenol,
Alcohols such as tetradecenol, pentadecenol, hexadecenol, heptadecenol, octadecenol, nonadecenol, eicosenol, heneicosenol, dococenol, tricocenol, tetracocenol, pentacocenol, hexacocenol, heptacocenol, octacocenol, octacosanoic acid octadecanoic acid, octacosanoic acid, octacosanoic acid, octacosanoic acid, octacosanoic acid Dodecyl, tridecyl octacosanoate, tetradecyl octacosanoate, pentadecyl octacosanoate, hexadecyl octacosanoate, heptadecyl octacosanoate, octadecyl octacosanoate, methyl decanoate, methyl undecanoate, methyl dodecanoate, methyl tridecanoate, methyl tetradecanoate, methyl pentadecanoate,
Methyl hexadecanoate, Methyl heptadecanoate, Methyl octadecanoate, Methyl nonadecanoate, Methyl eicosanate, Methyl heneicosanoate, Methyl docosanoate, Methyl tricosanoate, Methyl tetracosanoate, Methyl pentacosanoate, Methyl hexacosanoate, Methyl heptacosanoate, Octacosanoic acid Methyl, methyl nonacosanoate, methyl triacontanoate, methyl hentriacontanoate,
Methyl dotriacontanate, Methyl tritriacontanate, Methyl tetratriacontanate, Methyl pentatriacontanate, Methyl hexatriacontanate, Methyl heptatriacontanate, Methyl nonatriacontanate, Methyl tetracontanate, Hentetracontane Methyl acid, methyl dotetracontanate, methyl tritetraacontanate, methyl tetratetracontanate, methyl pentatetracontanate, methyl hexatetracontanate, methyl heptatetracontanate, methyl octatetracontanate, nonatetracontanate Methyl, methyl pentacontanate, methyl hempentacontanate, methyl dopentacontanate, methyl tripentacontanate, methyl tetrapentacontanate, methyl pentapentacontanate, hexapenta Methyl pentane acid, hepta penta proximal methyl, octa penta proximal methyl, nona penta proximal acid, methyl Hekisakontan acid,
Methyl dohexacontanoate, methyl decenoate, methyl undecenoate, methyl dodecenoate, methyl tridecenoate,
Methyl tetradecenoate, methyl pentadecenoate, methyl hexadecenoate, methyl heptadecenoate, methyl octadecenoate, methyl nonadecenoate, methyl eicosenoate,
Methyl henecosenoate, methyl docosenoate, methyl tricosenoate, methyl tetracosenoate, methyl pentacosenoate, methyl hexacosenoate, methyl heptacosenoate,
Methyl octacosenoate, methyl nonacosenoate, vinyl decanoate, vinyl undecanoate, vinyl dodecanoate, vinyl tridecanoate, vinyl tetradecanoate, vinyl pentadecanoate, vinyl hexadecanoate, vinyl heptadecanoate, vinyl octadecanoate, vinyl nonadecanoate, eicosanoic acid Vinyl, vinyl heneicosanoate, vinyl docosanoate, vinyl tricosanoate, vinyl tetracosanoate,
Vinyl pentacosanoate, vinyl hexacosanoate, vinyl heptacosanoate, vinyl octacosanoate, vinyl nonacosanoate, vinyl triacontanate, vinyl hentriacontanate, vinyl dotriacontanate, vinyl tritriacontanate, vinyl tetratriacontanate, penta Vinyl triacontanoate, vinyl hexatriacontanoate, vinyl heptatriacontanoate, vinyl nonatriacontanoate, vinyl tetracontanate, vinyl hentetracontanate, vinyl detetracontanate, vinyl tritetraacontanate, tetratetracontane Vinylate,
Vinyl pentatetracontanate, vinyl hexatetracontanate, vinyl heptatetracontanate, vinyl octatetracontanate, vinyl nonatetracontanate, vinyl pentacontanate, vinyl hempentacontanate,
Vinyl dopentacontanate, vinyl tripentacontanate, vinyl tetrapentacontanate, vinyl pentapentacontanate, vinyl hexapentacontanate, vinyl heptapentacontanate, vinyl octapentacontanate, vinyl nonapentacontanate, hexacontane Vinyl acetate, vinyl dohexacontanoate, vinyl decenoate, vinyl undecenoate, vinyl dodecenoate, vinyl tridecenoate, vinyl tetradecenoate, vinyl pentadecenoate,
Vinyl hexadecenoate, vinyl heptadecenoate, vinyl octadecenoate, vinyl nonadecenoate, vinyl eicosenoate, vinyl heneicosenoate, vinyl docosenoate, vinyl tricosenoate, vinyl tetracosenoate, vinyl pentacosenoate, vinyl hexacosenoate, vinyl heptacenoate, octacosenoic acid. Vinyl, vinyl nonacosenoate, phenyl decanoate, phenyl undecanoate, phenyl dodecanoate, phenyl tridecanoate, phenyl tetradecanoate, phenyl pentadecanoate, phenyl hexadecanoate, phenyl heptadecanoate, phenyl octadecanoate, phenyl nonadecanoate, phenyl eicosanoate, Phenyl heicosanoate, phenyl docosanoate, phenyl tricosanoate, phenyl tetracosanoate, phenyl pentacosanoate, hexa Phenyl sanate, phenyl heptacosanoate, phenyl octacosanoate, phenyl nonacosanoate, phenyl triacontanoate, phenyl hentriacontanate, phenyl dotriacontanoate, phenyl tritriacontanoate, phenyl tetratriacontanoate, phenyl pentatriacontanoate , Phenyl hexatriacontanoate, phenyl heptatriacontanoate,
Phenyl nonatriacontanoate, phenyl tetracontanoate, phenyl henetetracontanoate, phenyl dotetracontanoate, phenyl tritetraacontanoate, phenyl tetratetracontanoate, phenyl pentatetracontanoate, phenyl hexatetracontanoate, heptatetra Phenyl contanoate, phenyl octatetracontanoate, phenyl nonatetracontanoate, phenyl pentacontanoate, phenyl hempentacontanoate, phenyl dopentacontanoate, phenyl tripentacontanoate,
Phenyl tetrapentacontanate, phenyl pentapentacontanate, phenyl hexapentacontanate, phenyl heptapentacontanate, phenyl octapentacontanate, phenyl nonapentacontanate, phenyl hexacontanate, phenyl dodecacontanate, phenyl decenoate , Phenyl undecenoate, phenyl dodecenoate, phenyl tridecenoate, phenyl tetradecenoate,
Phenyl pentadecenoate, phenyl hexadecenoate, phenyl heptadecenate, phenyl octadecenoate, phenyl nonadecenoate, phenyl eicosenoate, phenyl heneicosenoate, phenyl docosenoate, phenyl tricosenoate, phenyl tetracosenoate, phenyl pentacosenoate, phenyl hexacosenoate, heptacosenoic acid Phenyl, phenyl octacosenoate, phenyl nonacosenoate, lauron, stearone, 19-heptatriacontanone, 20-nonatriacontanone, 21-hentetracontanone, 22-tritetracontanone, ketone octadecanoate , Co octadecanoate, Cu octadecanoate, Fe octadecanoate, K octadecanoate, Li octadecanoate, Mg octadecanoate, Mn octadecanoate, Kutadekan acid Ni, octadecanoic acid Pb, octadecanoic acid Sn, octadecanoic acid Zn, octadecanoic acid Zr, decanoic acid Ca, undecanoic acid Ca, dodecanoic acid Ca, tridecanoic acid Ca, tetradecanoic acid C
a, Ca pentadecanoate, Ca hexadecanoate, Ca heptadecanoate, Ca octadecanoate, C nonadecanoate C
a, Ca eicosanoate, Ca heneicosanoate, Ca docosanoate, Ca tricosanoate, Ca tetracosanoate, Ca pentacosanoate, Ca hexacosanoate, Ca heptacosanoate, Ca octacosanoate, Ca nonacosanoate, Ca triacontanate, Hentriacontane Acid Ca, calcium dotriacontanoate, Ca tritriacontanoate, Ca tetratriacontanoate, Ca pentatriacontanoate,
Hexatriacontanoic acid Ca, heptatriacontanoic acid Ca, nonatriacontanoic acid Ca, tetracontanoic acid C
a, Ca hentetracontanoate, C tetradecanoate
a, Ca tritetraacontanate, Ca tetratetracontanate, Ca pentatetracontanate, Ca hexatetracontanate, Ca heptatetracontanate, Ca octatetracontanate, Ca nonatetracontanate, Ca pentacontaneate, Hempentacontanoic acid Ca, dopentacontanoic acid Ca, tripentacontanoic acid Ca, tetrapentacontanoic acid Ca, pentapentacontanoic acid C
a, Ca hexapentacontanoate, Ca heptapentacontanoate, Ca octapentacontanoate, Ca nonapentacontanoate, Ca hexahexanoate, Ca hexadecanoate, Ca decenoate, Ca undecenoate, Ca dodecenoate, Tridecene Acid Ca, Ca tetradecenoate, Ca pentadecenoate, Ca hexadecenoate, Ca heptadecenate, Ca octadecenoate, Ca nonadecenate, Ca eicosenoate, Ca heneicosenoate, Ca docosenoate,
Metal salts such as Ca tricosenoate, Ca tetracosenoate, Ca pentacosenoate, Ca hexacosenoate, Ca heptacosenoate, Ca octacosenoate, Ca nonacosenoate, decyl imidazole, undecyl imidazole, dodecyl imidazole, tridecyl imidazole, tetradecyl imidazole, Pentadecyl imidazole, hexadecyl imidazole, heptadecyl imidazole, octadecyl imidazole, nonadecyl imidazole, eicosyl imidazole, hene eicosyl imidazole, docosyl imidazole, tricosyl imidazole, tetracosyl imidazole, pentacosyl imidazole, hexacocyl imidazole Derivatives of monocarboxylic acids such as imidazole are suitable.

Derivatives of dicarboxylic acids having 10 to 61 carbon atoms are not limited to the following, but include decanedioic acid amide, undecanedioic acid amide, dodecanedioic acid amide, tridecanedioic acid amide, and tetradecanedioic acid amide. , Pentadecanedioic acid amide, hexadecanedioic acid amide, heptadecanedioic acid amide, octadecanedioic acid amide, nonadecanedioic acid amide, eicosane diacid amide, heneicosanodioic acid amide, docosanedioic acid amide, tricosanedioic acid amide,
Tetracosane diacid amide, pentacosane diacid amide, hexacosane diacid amide, heptacosane diacid amide, octacosane diacid amide, nonacosane diacid amide, triacontanedioic acid amide, hentriacontanedioic acid amide, dotriacontane diacid amide, Tritriacontanedioic acid amide, tetratriacontanedioic acid amide, pentatriacontanedioic acid amide, hexatriacontanedioic acid amide, heptatriacontanedioic acid amide, nonatriacontanedioic acid amide, tetracontanedioic acid amide, hentetra Contanedioic acid amide, detetracontanedioic acid amide,
Tritetraacontanedioic acid amide, tetratetracontanedioic acid amide, pentatetracontanedioic acid amide, hexatetracontanedioic acid amide, heptatetracontanedioic acid amide, octatetracontanedioic acid amide, nonatetracontanedioic acid amide, Pentacontanedioic acid amide, hempentacontanedioic acid amide, dopentacontanedioic acid amide, tripentacontanedioic acid amide, tetrapentacontanedioic acid amide, pentapentacontanedioic acid amide,
Hexapentacontanedioic acid amide, heptapentacontanedioic acid amide, octapentacontanedioic acid amide, nonapentacontanedioic acid amide, hexacontanedioic acid amide, dohexacontanedioic acid amide, decenedioic acid amide,
Undecenedioic acid amide, dodecenedioic acid amide, tridecenedioic acid amide, tetradecenedioic acid amide, pentadecenedioic acid amide, hexadecenedioic acid amide, heptadecenedioic acid amide, octadecenedioic acid amide, nonadecenedioic acid amide, eicosenedioic acid amide, Heneicosenedioic acid amide, docosenedioic acid amide, tricosenedioic acid amide, tetracosenedioic acid amide, pentacosenedioic acid amide, hexacosenedioic acid amide, heptacosenedioic acid amide, octacosenedioic acid amide, nonacosenedioic acid amide, etc. Acid amine, undecanedioic acid amine, dodecanedioic acid amine, tridecanedioic acid amine, tetradecanedioic acid amine, pentadecanedioic acid amine, hexadecanedioic acid amine, heptadecanedioic acid amine, octadecanedioic acid amine, nonadecanedioic acid amine Amine, eicosane diacid amine, hene eicosane diacid amine, docosane diacid amine, tricosane diacid amine, tetracosane diacid amine, pentacosane diacid amine, hexacosane diacid amine, heptacosane diacid amine, octacosane diacid amine, nonacosan diacid amine Amine, triacontanedioic acid amine, hentriacontanedioic acid amine, dotriacontanedioic acid amine, tritriacontanedioic acid amine, tetratriacontanedioic acid amine, pentatriacontanedioic acid amine, hexatriacontanedioic acid amine, Heptatriacontanedioic acid amine,
Nonatriacontanedioic acid amine, tetracontanedioic acid amine, hentetracontanedioic acid amine, dotetracontanedioic acid amine, tritetraacontanedioic acid amine, tetratetracontanedioic acid amine, pentatetracontanedioic acid amine, hexa Tetracontanedioic acid amine, heptatetracontanedioic acid amine, octatetracontanedioic acid amine, nonatetracontanedioic acid amine, pentacontanedioic acid amine, hempentacontanedioic acid amine, dopentacontanedioic acid amine, tripentacontane Amine diacid,
Tetrapentacontanedioic acid amine, pentapentacontanedioic acid amine, hexapentacontanedioic acid amine, heptapentacontanedioic acid amine, octapentacontanedioic acid amine, nonapentacontanedioic acid amine, hexacontanedioic acid amine, dohexacon Tannedic acid amine, decenedioic acid amine, undecenedioic acid amine, dodecenedioic acid amine, tridecenedioic acid amine, tetradecenedioic acid amine,
Pentadecenedioic acid amine, hexadecenedioic acid amine, heptadecenedioic acid amine, octadecenedioic acid amine, nonadecenedioic acid amine, eicosenedioic acid amine, heneicosenedioic acid amine, docosenedioic acid amine, tricosenedioic acid amine, tetracosenedioic acid amine, Amines such as pentacocenedioic acid amine, hexacocenedioic acid amine, heptacocenedioic acid amine, octacocenedioic acid amine, nonacocenedioic acid amine, decanedioic acid anilide, undecanedioic acid anilide, dodecanedioic acid anilide, tridecanedioic acid anilide,
Tetradecanedioic acid anilide, pentadecanedioic acid anilide, hexadecanedioic acid anilide, heptadecanedioic acid anilide, octadecanedioic acid anilide, nonadecanedioic acid anilide, eicosanedioic acid anilide, heneicosanedioic acid anilide, docosanedioic acid anilide, tricosanedioic acid anilide, Tetracosane diacid anilide, pentacosane diacid anilide, hexacosane diacid anilide, heptacosane diacid anilide, octacosane diacid anilide, nonacosane diacid anilide, triacontane diacid anilide, gentriacontane diacid anilide, dotriacontane diacid anilide, Tritriacontanedioic acid anilide, tetratriacontanedioic acid anilide, pentatriacontanedioic acid anilide, hexatriacontanedioic acid anilide, heptatriacontanedioic acid anilide, no Tricontanedioic acid anilide, tetracontanedioic acid anilide, hentetracontanedioic acid anilide, dotetracontanedioic acid anilide, tritetraacontanedioic acid anilide, tetratetracontanedioic acid anilide, pentatetracontanedioic acid anilide, hexatetra Contanedioic acid anilide, heptatetracontanedioic acid anilide, octatetracontanedioic acid anilide, nonatetracontanedioic acid anilide, pentacontanedioic acid anilide, hempentacontanedioic acid anilide, dopentacontanedioic acid anilide, tripentacontane dianidide Acid anilide, tetrapentacontanedioic acid anilide, pentapentacontanedioic acid anilide, hexapentacontanedioic acid anilide,
Heptapentacontanedioic acid anilide, octapentacontanedioic acid anilide, nonapentacontanedioic acid anilide,
Hexacontanedioic acid anilide, dohexacontanedioic acid anilide, decenedioic acid anilide, undecenedioic acid anilide, dodecenedioic acid anilide, tridecenedioic acid anilide,
Tetradecenedioic acid anilide, pentadecenedioic acid anilide, hexadecenedioic acid anilide, heptadecenedioic acid anilide, octadecenedioic acid anilide, nonadecenedioic acid anilide, eicosenedioic acid anilide, heneicosenedioic acid anilide, docosenedioic acid anilide, tricosenedioic acid anilide, Tetracosenedioic acid anilide, pentacosenedioic acid anilide, hexacosenedioic acid anilide, heptacosenedioic acid anilide, octacosenedioic acid anilide, nonacosenedioic acid anilide and other anilides, decanedioic acid alcohol, undecanedioic acid alcohol, dodecanedioic acid alcohol, tridecanedioic acid. Acid alcohol, tetradecanedioic acid alcohol, pentadecanedioic acid alcohol, hexadecanedioic acid alcohol, heptadecanedioic acid alcohol, octadecanedioic acid alcohol, nonadecane Acid alcohol, eicosane diacid alcohol, heneicosane diacid alcohol, docosane diacid alcohol, tricosane diacid alcohol, tetracosane diacid alcohol, pentacosane diacid alcohol, hexacosane diacid alcohol, heptacosane diacid alcohol, octacosane diacid alcohol, nonacosan diacid alcohol Acid alcohol, triacontanedioic acid alcohol, hentriacontanedioic acid alcohol, dotriacontanedioic acid alcohol, tritriacontanedioic acid alcohol, tetratriacontanedioic acid alcohol, pentatriacontanedioic acid alcohol, hexatriacontanedioic acid alcohol , Heptatriacontanedioic acid alcohol, nonatriacontanedioic acid alcohol, tetracontanedioic acid alcohol, hentetracontanedioic acid alcohol, doteto Contanedioic acid alcohol, tritetraacontanedioic acid alcohol, tetratetracontanedioic acid alcohol, pentatetracontanedioic acid alcohol, hexatetracontanedioic acid alcohol, heptatetracontanedioic acid alcohol, octatetracontanedioic acid alcohol, nonatetra Contanedioic acid alcohol, pentacontanedioic acid alcohol, hempentacontanedioic acid alcohol, dopentacontanedioic acid alcohol, tripentacontanedioic acid alcohol, tetrapentacontanedioic acid alcohol, pentapentacontanedioic acid alcohol, hexapentacontanedioic acid Acid alcohol,
Heptapentacontanedioic acid alcohol, octapentacontanedioic acid alcohol, nonapentacontanedioic acid alcohol, hexacontanedioic acid alcohol, dohexacontanedioic acid alcohol, decenedioic acid alcohol, undecenedioic acid alcohol, dodecenedioic acid alcohol, tridecene Diacid alcohol, tetradecenedioic acid alcohol, pentadecenedioic acid alcohol, hexadecenedioic acid alcohol,
Heptadecenedioic acid alcohol, octadecenedioic acid alcohol, nonadecenedioic acid alcohol, eicosenedioic acid alcohol, heneicosenedioic acid alcohol, docosenedioic acid alcohol, tricosenedioic acid alcohol, tetracosenedioic acid alcohol, pentacosenedioic acid alcohol, hexacosenedioic acid alcohol, Heptacosenedioic acid alcohol,
Alcohols such as octacocenedioic acid alcohol, nonacocenedioic acid alcohol, decyl octacosanedioate, undecyl octacosanedioate, dodecyl octacosanedioate, tridecyl octacosanedioate, tetradecyl octacosanedioate, hexadecyl octacosanedioate, hexadecyl octacosanedioate, octacosanedioic acid Heptadecyl acid, Octacosyl octacosanedioate, Methyl decanedioate, Methyl undecanedioate, Methyl dodecanedioate, Methyl tridecanedioate, Methyl tetradecanedioate, Methyl pentadecanedioate, Methyl hexadecanedioate, Methyl heptadecanedioate, Octadecanedioate Methyl acid, methyl nonadecanedioate,
Methyl eicosane diate, methyl heneicosane diate, methyl docosane diate, methyl tricosane diate, methyl tetracosane diate, methyl pentacosane diate, methyl hexacosane diate, methyl heptacosane diate, methyl octacosane diate, methyl nonacosane diate, Methyl triacontanedioate, methyl hentriacontanedioate, methyl dotriacontanedioate, methyl tritriacontanedioate, methyl tetratriacontanedioate, methyl pentatriacontanedioate, methyl hexatriacontanedioate, heptatria Methyl contanedioate, Methyl nonatriacontanedioate, Methyl tetracontanedioate, Methyl hentetracontanedioate, Methyl detetracontanedioate, Methyl tritetraacontanedioate, Methyl tetratetracontanedioate, Pentatetraco Tan diacid methyl, hexamethylene tetra proximal diacid methyl, hepta tetra proximal diacid methyl,
Methyl octatetracontanedioate, methyl nonatetracontanedioate, methyl pentacontanedioate, methyl hempentacontanedioate, methyl dopentacontanedioate, methyl tripentacontanedioate, methyl tetrapentacontanedioate, pentapentacon Methyl tandioate, Methyl hexapentacontanedioate, Methyl heptapentacontanedioate, Methyl octapentacontanedioate, Methyl nonapentacontanedioate, Methyl hexacontanedioate, Methyl dohexacontanedioate, Methyl decenedioate , Methyl undecenedioate, methyl dodecenedioate, methyl tridecenedioate, methyl tetradecenedioate, methyl pentadecenedioate, methyl hexadecenedioate, methyl heptadecenedioate, methyl octadecenedioate, methyl nonadecenedioate,
Methyl eicosendioate, methyl heneicosendioate, methyl docosenedioate, methyl tricosenedioate, methyl tetracosenedioate, methyl pentacosenedioate, methyl hexacosenedioate, methyl heptacosenedioate, methyl octacosenedioate, methyl nonacosendioate, Vinyl decanedioate,
Vinyl undecanedioate, vinyl dodecanedioate, vinyl tridecanedioate, vinyl tetradecanedioate, vinyl pentadecanedioate, vinyl hexadecanedioate, vinyl heptadecanedioate, vinyl octadecanedioate, vinyl nonadecanedioate, vinyl eicosanedioate, Heneicosane vinyl diacid, vinyl docosane diacid, vinyl tricosane diacid, vinyl tetracosane diacid, vinyl pentacosane diacid, vinyl hexacosane diacid, vinyl heptacosane diacid, vinyl octacosane diacid, vinyl nonacosane diacid, vinyl triacontane diacid. , Hentriacontane diacid vinyl, Dotriacontane diacid vinyl, Tritriacontane diacid vinyl, Tetratriacontane diacid vinyl, Pentatriacontane diacid vinyl, Hexatriacontane diacid vinyl,
Vinyl heptatriacontanedioate, vinyl nonatriacontanedioate, vinyl tetracontanedioate, vinyl hentetracontanedioate, vinyl detetracontanedioate, vinyl tritetraacontanedioate, vinyl tetratetracontanedioate, penta Vinyl tetracontanedioate, vinyl hexatetracontanedioate, vinyl heptatetracontanedioate, vinyl octatetracontanedioate, vinyl nonatetracontanedioate, vinyl pentacontanedionate, vinyl hempentacontanedioate, dopentacontane Vinyl diacid, vinyl tripentacontane diacid, vinyl tetrapentacontane diacid, vinyl pentapentacontane diacid, vinyl hexapentacontane diacid, vinyl heptapentacontane diacid, vinyl octapentacontane diacid, nonapentacontane di Acid vinyl Le, Hekisakontan diacid vinyl,
Vinyl dodecacontanedioate, vinyl decenedioate, vinyl undecenedioate, vinyl dodecenedioate, vinyl tridecenedioate, vinyl tetradecenedioate, vinyl pentadecenedioate, vinyl hexadecenedioate, vinyl heptadecenedioate, octadecenedioic acid Vinyl, vinyl nonadecenedioate, vinyl eicosenedioate, vinyl heneicosenedioate, vinyl docosenedioate, vinyl tricosenedioate, vinyl tetracosenedioate, vinyl pentacosenedioate, vinyl hexacosenedioate, vinyl heptacosenedioate, octacosenedioic acid. Vinyl, vinyl nonacosenedioate, phenyl decanedioate, phenyl undecanedioate, phenyl dodecanedioate, phenyl tridecanedioate, phenyl tetradecanedioate, phenyl pentadecanedioate, phenyl hexadecanedioate, heptadecanedioate Phenyl, phenyl octadecanedioate, phenyl nonadecanedioate, phenyl eicosanedioate, phenyl heneicosanedioate, phenyl docosanedioate, phenyl tricosanedioate, phenyl tetracosanedioate, phenyl pentacosanedioate, phenyl hexacosanedioate, heptacosanodioate Phenyl, phenyl octacosanedioate, phenyl nonacosanedioate, phenyl triacontanedioate, phenyl hentriacontanedioate, phenyl dotriacontanedioate, phenyl tritriacontanedioate, phenyl tetratriacontanedioate, pentatriacontanedioate Acid phenyl, hexatriacontanedioic acid phenyl, heptatriacontanedioic acid phenyl, nonatriacontanedioic acid phenyl, tetracontanedioic acid phenyl, hentetracontanedioic acid phenyl, Torakontan diacid phenyl, tri tetra Acon Tan diacid phenyl,
Phenyl tetratetracontanedioate, phenyl pentatetracontanedioate, phenyl hexatetracontanedioate, phenyl heptatetracontanedioate, phenyl octatetracontanedioate, phenyl nonatetracontanedioate, phenyl pentacontanedioic acid, hempentacone Phenyl tandioate, phenyl dopentacontanedioate, phenyl tripentacontanedioate, phenyl tetrapentacontanedioate, phenyl pentapentacontanedioate, phenyl hexapentacontanedioate, phenyl heptapentacontanedioate, octapentacontane Phenyl diacid, phenyl nonapentacontanedioate, phenyl hexacontanedioate, phenyl dohexacontanedioate, phenyl decenedioate, phenyl undecenedioate, phenyl dodecenedioate, tridecenedioic acid Nyl, phenyl tetradecenedioate, phenyl pentadecenedioate, phenyl hexadecenedioate, phenyl heptadecenedioate, phenyl octadecenedioate, phenyl nonadecenedioate, phenyl eicosendioate, phenyl henecosenedioate, phenyl docosenedioate, tricosenedioic acid. Phenyl, phenyl tetracosenedioate, phenyl pentacosenedioate, phenyl hexacosenedioate, phenyl heptacosenedioate, phenyl octacosenedioate, phenyl nonacosenedioic acid, etc., ketones, Ca octadecanedioate Co, octadecanedioate Co, octadecanedioate Cu, Fe octadecanedioate, K octadecanedioate, Li octadecanedioate, Mg octadecanedioate, Mn octadecanedioate, Ni octadecanedioate,
Octadecanedioic acid Pb, octadecanedioic acid Sn, octadecanedioic acid Zn, octadecanedioic acid Zr, decanedioic acid C
a, Ca undecanedioate, Ca dodecanedioate, Ca tridecanedioate, Ca tetradecanedioate, Ca pentadecanedioate, Ca hexadecanedioate, Ca heptadecanedioate,
Octadecanedioic acid Ca, nonadecanedioic acid Ca, eicosane diacid Ca, hene eicosane diacid Ca, docosandioic acid C
a, Ca tricosanedioate, Ca tetracosane diate, Ca pentacosane diate, Ca hexacosane diate, Ca heptacosane diate, Ca octacosane diate, C nonacosane diate
a, Ca triacontanedioate, Ca hentriacontanedioate, Ca dotriacontanedioate, Ca tritriacontanedioate, Ca tetratriacontanedioate, Ca pentatriacontanedioate, Ca hexatriacontanedioate,
Heptatriacontanedioic acid Ca, nonatriacontanedioic acid Ca, tetracontanedioic acid Ca, hentetracontanedioic acid Ca, dotetracontanedioic acid Ca, tritetraacontanedioic acid Ca, tetratetracontanedioic acid Ca, penta Tetracontanedioic acid Ca, Hexatetracontanedioic acid Ca, Heptatetracontanedioic acid Ca, Octatetracontanedioic acid Ca, Nonatetracontanedioic acid Ca, Pentacontanedioic acid Ca, Hempentacontanedioic acid Ca, Dopentacontane Diacid Ca, tripentacontane diacid Ca,
Tetrapentacontanedioic acid Ca, pentapentacontanedioic acid Ca, hexapentacontanedioic acid Ca, heptapentacontanedioic acid Ca, octapentacontanedioic acid Ca,
Nonapentacontanedioic acid Ca, Hexacontanedioic acid C
a, Ca dohexacontanedioate, Ca decenedioate, Ca undecenedioate, Ca dodecenedioate, Tridecenedioate C
a, Ca tetradecenedioic acid, Ca pentadecenedioic acid, Ca hexadecenedioic acid, Ca heptadecenedioic acid, Ca octadecenedioic acid, Ca nonadecenedioic acid, Eicosendioic acid C
a, Ca heneicosendioate, Ca docosenedioate, Ca tricosenedioate, Ca tetracosenedioate, Ca pentacosenedioate, Ca hexacosenedioate, C heptacosenedioate
Derivatives of dicarboxylic acids such as metal salts of a, Ca octacosenedioate, Ca nonacosenedioate and the like are preferable.

[0024]

According to the structure of the first invention, the organic low molecular weight substance is selected from the group of saturated carboxylic acids having carbon numbers in the range of 27 to 61 and derivatives thereof, and at least gentriacontanoic acid and nonacosan. A reversible thermosensitive recording material containing three kinds of acid and tritriacontanoic acid as main components is constituted. Since such a predetermined saturated carboxylic acid and / or derivative thereof has a higher melting point than that of a group having 26 or less carbon atoms, the temperature required for changing the layer of the recording material according to the present invention from a cloudy state to a transparent state. Is expected to be higher than before. Further, as the organic low-molecular substance, at least three types of main constituents, hentriacontanoic acid, nonacosanoic acid and tritriacontanoic acid, are used, so that each saturated carboxylic acid does not change from a cloudy state to a transparent state. Since it is considered that the change in the recording state is not completed, the storage stability of the recording state is considered to be higher than that when one saturated carboxylic acid having 27 to 61 carbon atoms is used. Further, when a saturated carboxylic acid having 27 to 61 carbon atoms and / or a derivative thereof is used as the organic low molecular weight substance, the change temperature of transparency of the reversible thermosensitive recording material can be surely improved, but on the other hand, Since the molecular weight becomes high, it becomes difficult to prepare a coating solution for forming the layer of the reversible thermosensitive recording material, or the price of the reversible thermosensitive recording material is increased because the carboxylic acid and / or its derivative is not common. . In the constitution which further contains a monocarboxylic acid, a dicarboxylic acid or the like having 10 to 26 carbon atoms, the coating solution can be easily adjusted and a reversible thermosensitive recording material can be prepared as compared with the case where only a saturated carboxylic acid having 27 or more carbon atoms is used. The price can be reduced. It should be noted that, among these monocarboxylic acids and the like, those having 9 or less carbon atoms are already liquid at room temperature and are therefore unsuitable as organic low molecular weight substances in reversible thermosensitive recording materials.

Further, according to the constitution of the second invention, a reversible thermosensitive recording medium making use of the characteristics of the first invention can be obtained.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the first and second inventions of this application will be described below with reference to the drawings. It should be noted that the drawings used for the description are only schematically shown so that the present invention can be understood. Further, it is understood that the materials and numerical conditions used in the following examples are merely examples within the scope of the present invention, and therefore the present invention is not limited to these materials and numerical conditions. I want to.

1. Description of Examples of First Invention (Reversible Thermosensitive Recording Material) 1-1. Example 1 Polyvinyl acetal (S-REC KS-1 (trade name) manufactured by Sekisui Chemical Co., Ltd.) is prepared as a matrix material. As the organic low molecular weight substance, those shown in the column S1 of Table 1 (hereinafter referred to as “S1”) are prepared. This S1 is Preval S-30 manufactured by Miyoshi Yushi Co., Ltd.
The (trade name) is refined and adjusted by the applicant of this application. As a result of gas chromatography analysis by the applicant of the present application, this S1 contains 22 kinds of saturated carboxylic acids selected from the group of saturated carboxylic acids having a carbon number of 27 to 61 as shown in Table 1. It was something to do. However, the saturated carboxylic acid having an odd number of carbon atoms and the saturated carboxylic acid having an even number of carbon atoms are about 9: 1 in terms of their content by weight (9 for an odd number of carbon atoms), and 18 mol% of Hentriacontanoic acid, 13 mol% of Nonacosanoic acid and 1 mol of Tritriacontanoic acid
It contains 5 mol%. The numerical values in Table 1 show the content of each saturated carboxylic acid in S1 in mol%. In addition, each saturated carboxylic acid listed in Table 1 has a carbon number of 27 in the uppermost row in Table 1, and the carbon number increases by one in the descending order.

6 parts by weight of S-REC KS-1 and 3 parts by weight of S1 were dissolved in 50 parts by weight of tetrahydrofuran to prepare a coating solution for forming a layer of the reversible thermosensitive recording material of Example 1.

Next, a substrate made of polyethylene terephthalate in this case is prepared as a support. Then, the coating solution for forming the layer of the reversible thermosensitive recording material of Example 1 was applied onto this substrate by the bar coating method and further dried in the atmosphere at a temperature of 120 ° C. to form a layer of the reversible thermosensitive recording material. Form. The drying time is the time that can remove the solvent tetrahydrofuran.

The hysteresis curve of the change in transparency with respect to temperature of the sample of Example 1 (layer of the reversible thermosensitive recording material) thus prepared is examined. The results are shown in FIG. 1, in which the vertical axis represents the transmittance and the horizontal axis represents the temperature. In the reversible thermosensitive recording material of Example 1, the reversible thermosensitive recording material had a temperature of 120 ° C to 200 ° C (200 ° C).
Is due to the softening point of the matrix material) and then 5
When rapidly cooled with a temperature gradient of 0 ° C./sec or more (history indicated by 11 in FIG. 1), a transparent state is obtained, which is 90%.
After heating at a temperature of ℃ to 200 ℃, and then slowly cooling with a temperature gradient of 50 ℃ / sec or less (assuming the history shown by 13 in FIG. 1)
It turned out to be cloudy. Further, the sample in the cloudy state and the transparent state is allowed to stand at a predetermined temperature (in this case, each temperature of 40, 50, 60, 70, 80 ° C.) for a predetermined time (100 hours in this case). The concentration of each sample before and after the test of leaving it in such a hot atmosphere is measured with a Macbeth densitometer (in this case, RD920 manufactured by Sakata Inx Co., Ltd. is used). The initial concentration before the heat atmosphere leaving test and the concentration after standing at each temperature were values as shown in the column of Example 1 in Table 2 below. It should be noted that the concentration of only the polyethylene terephthalate substrate as the support is 1.83.

1-2. Example 2 As a matrix material, polyvinyl acetal (S-REC KS-1 (trade name) manufactured by Sekisui Chemical Co., Ltd.) is prepared as in Example 1. Table 1 below shows organic low-molecular substances.
The items shown in the column S2 (hereinafter referred to as “S2”) are prepared. This S2 is Preval S-30 manufactured by Miyoshi Yushi Co., Ltd. As a result of gas chromatography analysis by the applicant of the present application, this S2 contains 21 kinds of saturated carboxylic acids selected from the group of saturated carboxylic acids having a carbon number of 27 to 61 as shown in Table 1. It was something to do. However, the saturated carboxylic acid having an odd number of carbon atoms and the saturated carboxylic acid having an even number of carbon atoms are about 9: 1 in terms of their content by weight (9 for an odd number of carbon atoms), and 20 mol% of Hentriacontanoic acid, 16 mol% of Nonacosanoic acid and 1 mol of Tritriacontanoic acid
It contains 6 mol%. The numerical values in Table 1 show the content of each saturated carboxylic acid in S2 in mol%.

6 parts by weight of S-REC KS-1 and 3 parts by weight of S2 were dissolved in 50 parts by weight of tetrahydrofuran to prepare a coating solution for forming a layer of the reversible thermosensitive recording material of Example 2.

Then, a layer of the reversible thermosensitive recording material of Example 2 was formed on the substrate by the same procedure as in Example 1 to obtain an experimental sample. Further, in the same procedure as in Example 1, the hysteresis curve of the change in transparency with respect to temperature is examined, and further, the standing test at a predetermined temperature is conducted.

The sample of Example 2 had the same heat application conditions (heat history as that of Example 1) in the transparent state and the cloudy state with respect to heat.
It was found to be obtained by (see FIG. 1). Further, the initial concentration before the standing test at the predetermined temperature and the concentration after the standing at each temperature were values as shown in the column of Example 2 in Table 2 below.

1-3. Example 3 A copolymer of vinylidene chloride and acrylonitrile (Saran F310 (trade name) manufactured by Dow Chemical Co.) is prepared as a matrix material.

6 parts by weight of the above-mentioned Saran F310 and 3 parts of S1 used in Example 1 were added to 50 parts by weight of tetrahydrofuran.
Part by weight is dissolved to prepare a coating solution for forming the layer of the reversible thermosensitive recording material of Example 3.

Then, a layer of the reversible thermosensitive recording material of Example 3 was formed on the substrate by the same procedure as in Example 1 to obtain an experimental sample. Further, in the same procedure as in Example 1, the hysteresis curve of the change in transparency with respect to temperature is examined, and further, the standing test at a predetermined temperature is conducted.

The sample of Example 3 exhibited stable transparency when heated to 83 ° C. and cooled, and returned to an opaque state only when reheated to a temperature of 87 ° C. or higher. Do you get it. Further, the initial concentration before the standing test at the predetermined temperature and the concentration after the standing test at each temperature were values as shown in the column of Example 3 in Table 2 described later.

1-4. Example 4 As a matrix material, VYHH made of a copolymer of vinyl chloride and vinyl acetate (UCC (Union Carbait Co.))
(Product name) is prepared.

6 parts by weight of VYHH and 3 parts by weight of S1 used in Example 1 are dissolved in 50 parts by weight of tetrahydrofuran to prepare a coating solution for forming a layer of the reversible thermosensitive recording material of Example 4.

Then, a layer of the reversible thermosensitive recording material of Example 4 was formed on the substrate by the same procedure as in Example 1 to obtain an experimental sample. Further, in the same procedure as in Example 1, the hysteresis curve of the change in transparency with respect to temperature is examined, and further, the standing test at a predetermined temperature is conducted.

The sample of Example 4 was the same as that of Example 3.
It was found that when this was heated to 83 ° C. and cooled, it showed stable transparency, and only when it was reheated to a temperature of 87 ° C. or higher, it returned to an opaque state. The initial concentration before the standing test at the predetermined temperature and the concentration after the standing test at each temperature were values as shown in the column of Example 4 in Table 2 described later.

1-5. Example 5 As a matrix material, as in Example 1, S-REC KS-
Prepare 1 (brand name). As an organic low-molecular substance, S1
And prepare cerotic acid. Here, cerotic acid is used as an example of a monocarboxylic acid having 10 to 26 carbon atoms.

6 parts by weight of S-REC KS-1, 3 parts by weight of S1, and 1 part by weight of cerotic acid were dissolved in 50 parts by weight of tetrahydrofuran to prepare a coating solution for forming a layer of the reversible thermosensitive recording material of Example 5. To prepare.

Then, a layer of the reversible thermosensitive recording material of Example 5 was formed on the substrate by the same procedure as in Example 1 to obtain an experimental sample. Further, in the same procedure as in Example 1, the hysteresis curve of the change in transparency with respect to temperature is examined, and further, the standing test at a predetermined temperature is conducted.

The sample of Example 5 had the same heat application conditions (heat history as that of Example 1) in the transparent state to heat and the cloudy state.
It was found to be obtained by (see FIG. 1). Further, the initial concentration before the standing test at the predetermined temperature and the concentration after the standing test at each temperature were values as shown in the column of Example 5 in Table 2 described later.

1-6. Example 6 As a matrix material, the same as in Example 1, S-REC KS-
Prepare 1 (brand name). As an organic low-molecular substance, S1
And prepare docosanol. Here, docosanol is a derivative of monocarboxylic acid having 10 to 61 carbon atoms and is used as an example of alcohol.

6 parts by weight of S-REC KS-1, 3 parts by weight of S1, and 1 part by weight of docosanol were dissolved in 50 parts by weight of tetrahydrofuran to prepare a coating solution for forming a layer of the reversible thermosensitive recording material of Example 6. Prepare.

Then, a layer of the reversible thermosensitive recording material of Example 6 was formed on the substrate by the same procedure as in Example 1 to obtain an experimental sample. Further, in the same procedure as in Example 1, the hysteresis curve of the change in transparency with respect to temperature is examined, and further, the standing test at a predetermined temperature is conducted.

The sample of Example 6 had the same heat application conditions (heat history as that of Example 1) in the transparent state to heat and the cloudy state.
It was found to be obtained by (see FIG. 1). Further, the initial concentration before the standing test at the predetermined temperature and the concentration after the standing at each temperature were values as shown in the column of Example 6 in Table 2 described later.

1-7. Comparative Examples 1 to 6: Reversible heat sensitivity of Comparative Example 1 in the same manner as in Example 1 except that 3 parts by weight of behenic acid (docosanoic acid) was used in place of S1 in the structure of Example 1 above. A coating solution for preparing a layer of recording material is prepared. Here, docosanoic acid is a saturated carboxylic acid having 22 carbon atoms and has 27 to 61 carbon atoms.
It is used as an example other than the saturated carboxylic acid in the range.

A layer of the reversible thermosensitive recording material of Comparative Example 2 was prepared in the same manner as in Example 1 except that 3 parts by weight of behenic acid (docosanoic acid) was used in place of S2 in the structure of Example 2 above. A coating solution for preparation is prepared.

A layer of the reversible thermosensitive recording material of Comparative Example 3 was prepared in the same manner as in Example 1 except that 3 parts by weight of behenic acid (docosanoic acid) was used in place of S1 in the structure of Example 3 above. A coating solution for preparation is prepared.

A layer of the reversible thermosensitive recording material of Comparative Example 4 was prepared in the same manner as in Example 1 except that 3 parts by weight of behenic acid (docosanoic acid) was used in place of S1 in the structure of Example 4 above. A coating solution for preparation is prepared.

Reversible thermosensitive recording of Comparative Example 5 was conducted in the same manner as in Example 1 except that 3 parts by weight of behenic acid (docosanoic acid) was used in place of S1 and cerotic acid in the constitution of Example 5 above. Prepare a coating solution for layering the material.

A reversible thermosensitive recording material of Comparative Example 6 was prepared in the same manner as in Example 1 except that 3 parts by weight of behenic acid (docosanoic acid) was used in place of S1 and docosanol in the constitution of Example 6 above. To prepare a coating solution for layer formation.

Next, using the coating solutions for forming the layers of the reversible thermosensitive recording materials of Comparative Examples 1 to 6, the reversible thermosensitive recording materials of Comparative Examples 1 to 6 were formed on the substrate in the same procedure as in Example 1. The layers are formed to obtain the experimental samples 1 to 6 of the comparative examples, respectively. Further, with respect to these samples of Comparative Examples 1 to 6, the hysteresis curve of the change in transparency with respect to temperature is examined in the same procedure as in Example 1, and further, the standing test at a predetermined temperature is performed.

The sample of Comparative Example 1 exhibited stable transparency when heated to 50 ° C. or higher and cooled, and at 80 ° C.
It was found that the opaque state was restored only by reheating to the above temperature.

The sample of Comparative Example 2 exhibited stable transparency when heated to 50 ° C. or higher and cooled, and also at 80 ° C.
It was found that the opaque state was restored only by reheating to the above temperature.

The sample of Comparative Example 3 exhibited stable transparency when heated to 72 ° C. and cooled, and returned to an opaque state only when reheated to a temperature of 77 ° C. or higher. Do you get it.

The sample of Comparative Example 4 exhibited stable transparency when heated to 50 ° C. or higher and cooled, and at 80 ° C.
It was found that the opaque state was restored only by reheating to the above temperature.

The sample of Comparative Example 5 exhibited stable transparency when heated to 50 ° C. or higher and cooled, and also at 80 ° C.
It was found that the opaque state was restored only by reheating to the above temperature.

The sample of Comparative Example 6 shows stable transparency when heated to 50 ° C. or higher and cooled, and at 80 ° C.
It was found that the opaque state was restored only by reheating to the above temperature.

The initial concentration of the sample of each comparative example before the test of leaving it in a hot atmosphere and the concentration after leaving it at each temperature were values shown in Table 2 below.

The following can be said from these examples and comparative examples. First, it can be seen that the temperature required for changing each sample of the example from the cloudy state to the transparent state is higher than 80 ° C. More specifically, in the third and fourth embodiments,
Since the temperature required to change from the cloudy state to the transparent state is the lowest in the examples, which is 83 ° C., the temperature required to change it from the cloudy state to the transparent state is higher than 83 ° C. in each sample of the examples. I understand. It is also found that when left in a hot atmosphere, the concentration does not change up to a temperature of at least 80 ° C (see Table 2).
In addition, it can be seen that among the examples, particularly, in the case where the polyvinyl acetal is used as the matrix material, the unique heat history characteristic shown in FIG. 1 is exhibited.

On the other hand, in the case of the comparative example, when left in a hot atmosphere, there is a difference in the temperature that changes between the comparative examples, but all of them should be in a transparent state up to a temperature of 80 ° C. Turns into a cloudy state (see Table 2). From these, it can be understood that the reversible thermosensitive recording material of the first invention can store the recording state once formed up to a temperature of at least 80 ° C.

Further, in the embodiment, the one having the smallest density difference between the white turbid state and the transparent state is that of the second or third embodiment, but the contrast is still 1.5 / 0.
It turns out that 55≈2.73. On the other hand, in the comparative example, the density difference between the cloudy state and the transparent state is the largest (best) is 1.5 / 0.6 = 2.5 in the initial state.
It turns out that From these, it can be understood that the reversible thermosensitive recording material of the first invention has a better contrast than before.

[0068]

[Table 1]

[0069]

[Table 2]

2. Description of Embodiments of Second Invention (Reversible Thermosensitive Recording Medium) Next, embodiments of the reversible thermosensitive recording medium of the second invention will be described.

2-1. First Embodiment of the Second Invention The most basic structural example (first embodiment) of the reversible thermosensitive recording medium of the second invention is a layer composed of the reversible thermosensitive recording material of the first invention (reversible thermosensitive recording). It is a structure in which a layer of material) and a support for maintaining the layer are laminated. The support may have any suitable shape, constituent material and film thickness depending on the design of the reversible thermosensitive recording medium. For example, a material that is transparent to visible light, one that reflects part or all of visible light, or one that absorbs part or all of visible light can be the support of the second invention. .

In the constitution of the second invention, the transparent portion and the opaque portion are selectively formed in the reversible thermosensitive recording layer by selectively heating the reversible thermosensitive recording layer from the reversible thermosensitive recording layer side. When the support is made of a material having good thermal conductivity, heating means is brought into contact with the support to heat the reversible thermosensitive recording layer through the support. As described above, the transparent portion and the opaque portion can be selectively formed (display can be performed) from the support side (from the back side of the medium). In the case where a display can be made from the support side as well, when a reversible thermosensitive recording medium is used as the display screen itself of a display device, a desired display can be performed without disposing a heating means on the side where a person views the medium. The advantage is obtained. If the display can be performed from the support side (from the back side of the medium), in addition to the above advantages, other advantages can be obtained depending on the design (details will be described in a corresponding embodiment later).

Examples of the constituent material of the support include, but are not limited to, polyethylene terephthalate, polyester, polypropylene, cellophane, polyvinyl chloride, polyolefin, polyvinyl alcohol,
Plastics such as polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate, polysulfone, fluororesin, polyacrylonitrile, polyether sulfane, polybutadiene and polyimide,
Paper, synthetic paper, inorganic fiber paper with good thermal conductivity, ceramics, metals, carbon powder and plastics in which metal powders are dispersed can be used.

In order to expand the applications of the reversible thermosensitive recording medium of the second invention and further improve its characteristics, a reversible thermosensitive recording medium is used as an intermediate layer in addition to the constitution of the first embodiment of the second invention. A protective layer for protection, an adhesive layer for improving the fixing strength between the constituents of the reversible thermosensitive recording medium, a reflective layer or a light absorbing layer (details will be described later), and an enhance for improving display contrast. One or more layers selected from the layers according to the design of the reversible thermosensitive recording medium, and further,
Any recording layer (recording layer in a meaning different from the reversible thermosensitive recording layer of the present invention) for recording bar code information or magnetic information which cannot be directly recognized by humans but can be read by an information reading device or the like The reversible thermosensitive recording medium can also be suitably arranged to form a reversible thermosensitive recording medium. These specific examples will be described by the following examples.

2-2. Second Embodiment of the Second Invention The reversible thermosensitive recording medium of the second embodiment is, as shown in the sectional view of FIG. 2, a support 21 and a kind of an intermediate layer provided on the support 21. The reflective layer or the light absorbing layer 23, and the layer 25 of the reversible thermosensitive recording material of the first invention provided on the reflective layer or the light absorbing layer 23 (hereinafter may be abbreviated as the reversible thermosensitive recording layer 25). It consists of and. Note that FIG.
In the figure, the black arrow with the word "heating" means that the reversible thermosensitive recording layer 25 is heated by the heating means from the direction of the arrow, and the white arrow with the word "light". Means that the medium is irradiated with light from this arrow direction, and the white arrow with the word "eye" means that the display of the medium can be seen from this arrow direction. Also, the broken line arrow with the word "heating" means that when the support has good heat conduction, the reversible thermosensitive recording layer 25 medium can be heated through the support by heating means from the direction of this arrow. (The same applies to each of the following examples.). In addition, in the cross-sectional views used in FIG. 2 and the following description, hatching showing the cross-section is attached only to the reflection layer or the light absorption layer 23 and the reversible thermosensitive recording layer 25, and hatching to other layers is omitted. is doing.

The reversible thermosensitive recording medium 27 of the second embodiment as described above was manufactured as follows. The support 21 is
Here, it is made of a polyethylene terephthalate substrate having a predetermined thickness. On this support 21, a coating solution prepared by dissolving vinyl chloride-vinyl acetate copolymer (VYHH manufactured by Union Carbide Co. (UCC)) as a binder and cadmium red as a color pigment in tetrahydrofuran is applied. When the obtained coating film is dried, a layer that mainly reflects red light and absorbs or transmits other light on the support 21 (both a reflective layer, a light absorbing layer, and a light transmitting layer depending on the wavelength of interest). However, from another perspective, a layer that can be called a colored layer, which will be referred to as a reflection layer or a light absorption layer 23) 23 is formed. In addition, a reversible thermosensitive recording layer 25 was formed on the reflection layer or the light absorption layer 23 thus produced by using each coating solution used in Examples 1 to 6 of the first invention. It is formed by the procedure described in the example.

The reversible thermosensitive recording medium 2 of the second embodiment
When a heating means (for example, a thermal head) was brought into contact with the reversible thermosensitive recording layer 25 of No. 7 to selectively heat the layer 25 to form a transparent portion (printed portion), printing with red letters was possible. Further, when an experiment was carried out in a hot atmosphere as in the first invention, it was found that no print deterioration was observed. Of course, also in the case of the second embodiment, as in the first embodiment, the support 21 is made of a material having good thermal conductivity, and the reversible thermosensitive recording layer 25 is heated from the support side through the support. May be.

The reflection layer or the light absorption layer 23 is not limited to the layer including a red pigment. The reflection layer or the light absorption layer 23 may be composed of a pigment other than red, or a layer containing a pigment or a layer containing metal powder such as copper powder or aluminum powder. Further, the reflecting layer or the light absorbing layer 23 may be formed by applying ink or the like on the support 21. Further, inks of a plurality of colors may be printed for the purpose of improving the display contrast. Further, when the reflection layer or the light absorption layer 23 is manufactured, pigments, dyes, and metal powders having good thermal conductivity may be used to improve the thermal responsiveness of the reversible thermosensitive recording medium. .

2-3. Third Embodiment of the Second Invention The reversible thermosensitive recording medium of the third embodiment has a reversible thermosensitive recording medium of the second embodiment as shown in the sectional view of FIG. A protective layer 29, which is transparent to visible light and protects the reversible thermosensitive recording layer 25, is provided on the thermosensitive recording layer 25. Examples of the constituent material of the protective layer 29 include, but are not limited to, polyester, polyethylene, polypropylene, cellophane, polyvinyl chloride, polyolefin, polyvinyl alcohol,
Plastic such as polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate, polysulfone, fluororesin, polyacrylonitrile, polyether sulfane, polybutadiene, UV curing resin, and inorganic such as SiO ₂ , TiO ₂ , Al ₂ O ₃ We can list substances. With respect to the film thickness of the protective layer 29, heat from a means (for example, a thermal head) for heating the reversible thermosensitive recording layer 25 is satisfactorily transferred to the reversible thermosensitive recording layer 25, and a function as a protective layer is obtained. A suitable film thickness within the range may be set.

On the surface of the protective layer 29, a character or a graphic (for example, the application of the reversible thermosensitive recording medium, for example, "○○"
Characters such as "XX card" may be printed. Also in the case of the third embodiment, as shown in FIG. 3B, the support can be made of a material having good heat conduction. In the case of this configuration, it is possible to print without providing heating means on the side of the medium viewed by the person, and it is difficult for the characters or figures printed on the surface of the protective layer 29 to be affected by the heat from the heating means. Benefits are obtained. This is the protective layer 2
9 When writing characters or figures on the surface with water-based or oil-based magic ink, it is considered to be useful in terms of protecting the written characters or figures.

If necessary, as shown in FIG. 3B, between the protective layer 29 and the reversible thermosensitive recording layer 25, and / or the reversible thermosensitive recording layer 25 and the reflective layer or the light absorbing layer. Layer 2
An adhesive layer 31 for improving the adhesive strength between the two layers 25 and 23 may be provided between the first and second layers as a kind of intermediate layer. Examples of the constituent material of the adhesive layer 31 include, but are not limited to, polyester resin, urethane resin, and epoxy resin. In addition, as another example of the intermediate layer,
A dedicated layer (printing layer) 33 for printing characters and graphics can be provided in an appropriate place on the reversible thermosensitive recording medium (not limited to that of the third embodiment). In FIG. 4 (A),
An example of a reversible thermosensitive recording medium having a printing layer 33 between the adhesive layer 31 and the protective layer 29, and in FIG. 4B, between the reflective or light absorbing layer 23 and the adhesive layer 31. Examples of the reversible thermosensitive recording medium having the printing layer 33 are shown. Of course, the provision of the adhesive layer and the printing layer is not limited to the third embodiment, but can be applied to other embodiments.

2-4. Fourth Embodiment of Second Invention The reversible thermosensitive recording medium of the fourth embodiment is the reversible thermosensitive recording medium shown in FIG. 3A of the third embodiment as shown in the sectional view of FIG. 5A. In addition to the structure of the thermosensitive recording medium, an enhance layer 35 for improving display contrast is provided between the reversible thermosensitive recording layer 25 and the reflective or light absorbing layer 23 as a kind of intermediate layer. . This enhancement layer 3
No. 5 enhances the contrast between the transparent portion and the cloudy portion formed on the reversible thermosensitive recording layer 25 to improve the display contrast. Examples of the constituent material of the enhancement layer 33 include, but are not limited to, polyester, polyethylene, polypropylene, cellophane, polyvinyl chloride, polyolefin, polyvinyl alcohol, and the like.
Plastic such as polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate, polysulfone, fluororesin, polyacrylonitrile, polyether sulfane, polybutadiene, etc.
Inorganic substances such as ₂ , TiO ₂ and Al ₂ O ₃ can be mentioned.

The enhancement layer may be composed of the air layer 35a. An example of this is shown in FIG. In the example of FIG. 5B, an adhesive layer 31 is provided in a part between the reflective layer or the light absorbing layer 23 and the reversible thermosensitive recording layer 25, and the reflective layer or the light absorbing layer 23 and the reversible thermosensitive layer are provided. Recording layer 25
The air layer 3 is formed in a portion between the
By forming 3a, an enhancement layer is formed.

Also in the case of the fourth embodiment, the support can be made of a material having good heat conduction. However,
It is considered that the embodiment in which the enhance layer is composed of the air layer 35a is not so effective because the degree of heat transfer to the reversible thermosensitive recording layer 25 is reduced by the air layer 35a.

2-5. Fifth Embodiment of the Second Invention The reversible thermosensitive recording layer 25 provided in the reversible thermosensitive recording medium of the second invention records visible characters and figures.
However, if the reversible thermosensitive recording medium of the second invention is capable of storing and rewriting coded information as well, it records and uses a composite information of a heat record and a coded record that can be directly viewed. It is preferable because a reversible thermosensitive recording medium can be obtained. If such a reversible thermosensitive recording medium can be constructed, it can be used to construct a prepaid card, for example, and code information indicating a balance or the like can be stored in the recording layer. Furthermore, the balance information is read by an external reading device, and a new balance is calculated by the external control device from this information and the amount of money that has been used, and this new balance is displayed on the reversible thermosensitive recording layer and updated and recorded on the recording layer. It is preferable because the reversible thermosensitive recording medium can be widely applied. Hereinafter, an example (fifth embodiment) of a reversible thermosensitive recording medium having such a recording layer will be described.

The location of the recording layer capable of storing and rewriting the code information in the reversible thermosensitive recording medium can be arbitrarily determined according to the design of the reversible thermosensitive recording medium. In this embodiment, the second
A recording layer 37 is provided on the back surface of the support 21 of the reversible thermosensitive recording medium described with reference to FIG. 3A in the examples, and the second layer 37 is covered to protect the recording layer 37.
The example (see FIG. 6A) in which the protective layer 39 of FIG. Further, in the configuration of FIG. 6A, an enhancement layer 35 may be provided between the reversible thermosensitive recording layer 25 and the reflection layer or the light absorption layer 23, as a matter of course (FIG. 6B).
reference). The constituent material of the second protective layer 39 can be selected from various materials that can form the protective layer 29, for example.

The recording format on the recording layer 37 is not limited to this, but magnetic recording, optical recording, electrical recording, and recording by heat to record invisible code information. It can be one or more of the laws.
The recording layer 37 may be composed of, for example, the IC card itself.

Also in the case of the fifth embodiment, the support may be made of a material having good heat conduction.

2-6. Sixth Embodiment of the Second Invention The reversible thermosensitive recording medium of the sixth embodiment is a support (transparent support) composed of a material transparent to visible light, as shown in the sectional view of FIG. 7 (A). A reversible thermosensitive recording layer 25 and a transparent protective layer 29 are provided in this order on 41, and a transparent support 41 is provided.
Is provided with a reflection layer or a light absorption layer 23 on the back surface of the. In this configuration, a transparent support 41 is used as a support, and this is used as a reversible thermosensitive recording layer 25 and a reflection layer or a light absorption layer 2.
Since the transparent support 41 is disposed between the transparent support 41 and the transparent support 3, the transparent support 41 itself acts as an enhancement layer. of course,
As shown in FIG. 7B, in addition to the structure shown in FIG. 7A, an original enhancement layer 35 (or an air layer 35a may be provided) between the transparent support 41 and the reflection layer or the light absorption layer 23. May be.

As an example of the constituent material of the transparent support 41,
For example, transparent plastics such as polyester, polyethylene, polypropylene, cellophane, polyvinyl chloride, polyolefin, polyvinyl alcohol, polyvinylidene chloride, polystyrene, polyamide, polycarbonate, polyarylate, polysulfone, fluororesin, polyacrylonitrile, polyether sulfane, polybutadiene. And so on.

Also in the case of the sixth embodiment, for example, FIG.
In the configuration (A) or (B), the recording layer 37 and the second protective layer 39 may be provided below the reflection layer or the light absorption layer 23.

2-7. Seventh embodiment of the second invention Reversible thermosensitive recording medium described with reference to FIG. 3A, reversible thermosensitive recording medium described with reference to FIG.
The reversible thermosensitive recording medium described with reference to FIG.
In each structure of the reversible thermosensitive recording medium described with reference to (B), the reflection layer or the light absorption layer 23 is not provided, and the support 21 itself is composed of a transparent support (seventh embodiment). ). As an aspect of the seventh embodiment, an example in which the idea of the seventh embodiment is applied to the configuration of FIG. 3 (A) is shown in FIGS. 8 (A) and (B). Here, FIG. 8A shows that the reversible thermosensitive recording layer 2 is prepared by heating from the transparent protective layer 29 side.
5B is an example in which printing is performed on the supporting member 21. FIG. 8B shows that the supporting member 21 is made of a material having good thermal conductivity and a transparent material.
This is an example of printing on the reversible thermosensitive recording layer 25 by heating from the side. In both cases, an example is shown in which light is introduced from the transparent support 21 of the reversible thermosensitive recording medium. of course,
Light may be incident from the transparent protective film 29 side. In addition, as another aspect of the seventh embodiment, an example in which the idea of the seventh embodiment is applied to the configuration including the recording layer 37 is shown in FIG.
It shows in (C). That is, in FIG. 8C, the recording layer 37
And a second protective layer 39 for protecting the recording layer 37,
An example is shown in which the transparent support 41 is provided on a portion of the back surface that does not hinder the incidence of light. Of course, this figure 8
Also in the case of (C), the transparent support 41 is made of a material having good thermal conductivity, and the reversible thermosensitive recording layer 25 is provided through the transparent support 41.
May be heated.

2-8. Eighth Embodiment of Second Invention The reversible thermosensitive recording media of the above-mentioned first to seventh embodiments are
The data printed on the medium was viewed mainly from the protective film 29 side. However, the support 21 itself is replaced by the transparent support 41.
The print data may be viewed from the transparent support 21 side by arranging the reflective layer or the light absorbing layer 23 between the reversible thermosensitive recording layer 25 and the protective layer 29. Some examples will be described below. However, in the case of the eighth embodiment, the protective layer 29 need not have transparency.

First, FIG. 9A shows a reversible thermosensitive recording layer 25, a reflective layer or a light absorbing layer 23 on a transparent support 41.
And the protective layer 29 is provided in this order. Just
This corresponds to an example in which the medium in FIG. 3A is changed so that the display can be seen on the support side. Further, FIG. 9B shows an example in which an adhesive layer 31, a reversible thermosensitive recording layer 25, an adhesive layer 31, a reflective layer or a light absorbing layer 23, and a protective layer 29 are provided in this order on a transparent support 41. is there. This corresponds to an example in which the medium in FIG. 3B is changed so that the display can be seen on the support side. Further, FIG. 9C shows a printing layer 33, an adhesive layer 31, a reversible thermosensitive recording layer 25, an adhesive layer 3 on a transparent support 41.
1, an example in which the reflection layer or the light absorption layer 23 and the protective layer 29 are provided in this order. This corresponds to an example in which the medium of FIG. 4A is changed so that the display can be seen on the support side. In addition, FIG. 10A shows that the adhesive layer 3 is formed on the transparent support 41.
1, reversible thermosensitive recording layer 25, adhesive layer 31, printing layer 33,
This is an example in which the reflection layer or the light absorption layer 23 and the protection layer 29 are provided in this order. This corresponds to an example in which the medium of FIG. 4B is changed so that the display can be seen on the support side. Also,
FIG. 10B shows a reversible thermosensitive recording layer 25, an enhance 35, a reflecting layer or a light absorbing layer 23 on a transparent support 41.
And the protective layer 29 is provided in this order. Just
This corresponds to an example in which the medium of FIG. 5A is changed so that the display can be seen on the support side. Further, FIG. 10C shows an example in which a reversible thermosensitive recording layer 25, an enhancement layer composed of an air layer 35, a reflection layer or a light absorption layer 23, and a protective layer 29 are provided in this order on a transparent support 41. is there. Just Figure 5
This corresponds to an example in which the medium of (B) is changed so that the display can be seen on the support side. Further, FIG. 11A shows an example in which a reversible thermosensitive recording layer 25, a reflective layer or a light absorbing layer 23, a recording layer 37 and a second protective layer 39 are provided in this order on a transparent support 41. . This corresponds to an example in which the medium in FIG. 6A is changed so that the display can be seen on the support side. Also,
FIG. 11B shows a reversible thermosensitive recording layer 25, an enhancement layer 35 (which may be an air layer), a reflection layer or a light absorption layer 23, a recording layer 37 and a second layer on a transparent support 41. This is an example in which the protective layer 39 is provided in this order. Just
This corresponds to an example in which the medium in FIG. 6B is changed so that the display can be seen on the support side.

2-9. Ninth embodiment of the second invention In each of the above-mentioned first to eighth embodiments, as a support used when light is incident from the support side, a support having a structure in which light enters at right angles to the main surface of the support is mainly used. I was thinking. However, the support itself may have a property of changing the traveling direction of the light incident on the support. This is because, for example, restrictions on the design of the reversible thermosensitive recording medium due to the positional relationship between the reversible thermosensitive recording layer 25 and the light source can be reduced. The following example (9th Example) is the example.

FIG. 12 is a view showing one mode of this ninth embodiment. In this aspect, the end surface 51a of the plate-like body 51
A plate-like body having an optical path changing function that light is incident on the plate-like body 51 at a right angle and is emitted from the main surface of the plate-like body 51 (also referred to as an edge light system). An example in which 51 is used as a support for a reversible thermosensitive recording medium is shown. Specific examples of such a plate-like body 51 include acrylite (trade name) provided by Mitsubishi Rayon Co., Ltd. using an acrylic resin. Of course, the structure to which the idea of the ninth embodiment can be applied is not limited to that of FIG. 12, but can be widely applied to the structures of the above-described first to eighth embodiments.

3. Writing Information to Reversible Thermosensitive Recording Medium Next, an example of a method for writing information to the reversible thermosensitive recording medium of the second invention will be described in order to deepen understanding of the first and second inventions. FIG. 13 is a diagram which is used for the explanation, and is a diagram showing the relationship between the medium 100 and an example of an apparatus for writing a division method to the reversible thermosensitive recording medium 100 of the second invention.
In FIG. 13, reference numerals 200a to 200c denote recording apparatuses having somewhat different functions, and 300 stores information for recording (for example, "A", "I", "U", "E", "O") and the recording apparatus 200a. It is a control device for controlling ~ 200c. Here, the recording device 200a includes a thermal head 201 for printing information and a heating block (or heating roll) 202 for erasing information. Recording device 200b
In addition to the configuration of the recording device 200a, is provided with an optical reading device 203 for reading the information of the recording layer 37 described in the second invention, particularly for the information recording by the optical recording method. The recording device 200c comprises, in addition to the configuration of the recording device 200a, a read head 204 for reading the information of the recording layer 37, particularly the coded information, and a recording head 205 for writing the coded information.

3-1. When the reversible thermosensitive recording medium has, for example, the constitution without the recording layer 37 of the second invention, the user inserts the reversible thermosensitive recording medium 100 into the recording device 200a. The control device 300 senses that the reversible thermosensitive recording medium 100 has been inserted, and prints the recording information (for example, "A""I""U""E""O"). Send a command to. Receiving this command, the recording device 200a receives the thermal head 201
The reversible thermosensitive recording layer 25 of the reversible thermosensitive recording medium 100 is directly or protective layer 29 for a predetermined time at a predetermined power.
Alternatively, it is selectively heated via the support 21. If the reversible thermosensitive recording medium 100 is one having the thermal history characteristics shown in FIG. 1, “a” “i” “u” of the medium 100.
By heating the portion where "E" and "O" are to be printed to 120 to 200 ° C and then rapidly cooling it to room temperature, the corresponding portion becomes transparent and the other portions remain cloudy. The printing can be performed under the condition that the printing power is 0.1 W / dot and the printing time is 1 msec. Of course, this printing condition is an example.

After the printing is completed, the user takes out the reversible thermosensitive recording medium 100 from the recording device 200a. The medium 100 taken out had the printing portions of "A", "I", "U", "E" and "O" fixed in a transparent state. Further, the contrast indicated by the transmittance ratio between the transparent portion and the cloudy portion was, for example, 10 (which is the transmittance with respect to light having a wavelength of 550 nm). This allows the user to record the information “A” “I” “U” recorded on the medium 100.
"E" and "O" can be visually recognized. Further, this information "a""i""u""e""o" is held until the next use of the medium.

[0100] The user can also use the reversible thermosensitive recording medium 10
When erasing the previously recorded information of 0, the medium 100 is inserted into the recording device 200a. In the recording apparatus 200a, when the medium 100 is the one having the heat history characteristic of FIG. 1, the medium is heated by the heating roll 202 at a temperature in the range of 90 to 200 ° C. and then gradually cooled to room temperature. The medium 100 becomes opaque and the previous record is erased. When new information is recorded on the erased medium, it is processed by the above printing procedure.

3-2. When the reversible thermosensitive recording medium has, for example, the recording layer 37 of the above-mentioned second invention and particularly has a recording layer for storing information by the optical recording method, the user can use the reversible thermosensitive recording medium. The recording medium 100 is inserted into the recording device 200b. Then, the recording device 200b reads the optical information stored in the recording layer 37 by the optical reading device 203 and sends it to the control device 300.
If the optical information is, for example, the recognition information of the owner of the thermal recording medium 100, the control device can confirm the correctness of the user of the medium. The writing of information on the reversible thermosensitive recording layer and the erasing of information on the reversible thermosensitive recording layer can be performed by the same procedure as in 3-1 above.

3-3. Use when the reversible thermosensitive recording medium has, for example, the recording layer 37 of the second invention described above and has a recording layer, for example, a magnetic recording layer capable of storing and changing coded information. The person inserts the reversible thermosensitive recording medium 100 into the recording device 200c. Then, the recording device 200c reads the coded information stored in the recording layer 37 of the medium 100 with the read head 204 and sends it to the control device 300. Here, for example, the coded information can be, for example, balance information if the reversible thermosensitive recording medium 100 is considered as a prepaid card, for example. Control device 3
00 calculates a new balance from this balance information and the amount of money consumed by the user now, and further uses this new balance as the medium 10
The recording device 200c is instructed to perform recording on the recording layer 37 of 0 and display on the reversible thermosensitive recording layer 25 as visual information. The recording device 200c writes the new balance information to the recording layer 37 by the recording head 205, and
The reversible thermosensitive recording layer 25 is formed by the thermal head 202.

Among the reversible thermosensitive recording media of the second invention, one of which the display is viewed from one side of the medium and which is printed by heating from the other side of the medium (for example, FIG. 8). In the case of (B) and the medium shown in FIG. 9B), it is necessary to adjust the print signal of the thermal head 201 in the control device 300 so that the characters can be seen normally on the visual side.

4. Description of Reversible Thermosensitive Recording Device of Reference Example Next, a reversible thermosensitive recording device as a reference example (hereinafter abbreviated as “recording device”) will be described.

4-1. First Reference Example FIG. 14 is a diagram used for the description. This recording device
An overall erasing tool 63 composed of a frame 61 and a plate-shaped heating element for erasing the entire surface of the reversible thermosensitive recording layer (see FIG. 2 etc.) of the reversible thermosensitive recording medium provided on the frame 61.
And the reversible thermosensitive recording medium 100 provided in contact with the total erasing tool 63, a writing tool 65 for forming a printing portion (image) on the reversible thermosensitive recording medium 100, and the reversible thermosensitive recording medium 100. A local erasing tool 67 for erasing a part of the image formed on the first and a temperature control section 69 for controlling the temperature of the overall erasing tool 63 are provided.

Here, the frame 61 can be made of a suitable material such as metal or resin according to the design of the recording apparatus. Further, the total erasing tool 63 can be constituted by, for example, a panel heater. The entire eraser 63 is used for the reversible thermosensitive recording medium 100.
It is assumed that the temperature can be applied according to the characteristics of (see FIG. 1). The temperature control unit 69 that enables this can be configured by a conventionally known one. In addition, the reversible thermosensitive display 100
Uses the one described in the embodiment of the second invention. Although not shown, the writing instrument 65 includes a cylindrical main body, a head provided at the tip of the main body, a heat generating part built in the main body for heating the head, and a heat generating part. It has a power supply and an ON / OFF switch as a power switch. The head portion of the writing instrument 65 is preferably made of a material having a high thermal conductivity, such as a metal such as copper or ceramics. The shape of the head portion is preferably tapered, but the thickness of the head portion is preferably determined in consideration of the size of a character to be drawn. Further, the heat generating portion can be composed of a resistance heating element such as a nichrome heater or a ceramics heater. The power source for the heat generating portion may be either a DC power source (including batteries) or an AC power source.

According to the recording apparatus of the first reference example, when the full-face eraser 63 is operated according to the heat history condition 13 of FIG. 1, the recording layer of the recording medium 100 becomes cloudy. When the writing tool 65 in the on state is brought into contact with the cloudy screen, the recording layer becomes transparent at the part of the cloudy screen where the writing tool is in contact, and the color of the colored support becomes transparent, and in this case, the red printing portion. Is obtained. As a result, an image composed of a white background portion and a red printing portion can be formed on the display body. Further, when it is desired to erase only a part of the image, the image can be erased by bringing the local erasing tool 67 into contact with the part.

4-2. Second Reference Example Further, FIG. 15 is an explanatory diagram of a recording apparatus of the second reference example. The storage device of the second reference example is an example of a device in which the reversible thermosensitive recording medium of the second invention is applied to the display surface of a display. More specifically, the reversible thermosensitive recording medium of the second invention, which has a band shape and a closed loop shape (hereinafter, also referred to as loop medium 100), holds the loop medium 100, and when necessary. A first platen roll 206 and a second platen roll 207 for orbiting
A recording device 208 for recording information on the loop-shaped medium 100 and erasing information on the medium, running / stopping and traveling speed of the first and second platen rolls 206, 207, and the above information by the recording device 208. A device including a control device 301 for controlling recording and erasing. Here, the recording device 208 can be configured by the recording device 200a described with reference to FIG. 13, for example. Further, the control device can be constituted by any suitable device using known print control technology and transport control technology.

The recording apparatus of the second reference example can be used as, for example, an electronic bulletin board when the display is performed while moving the loop-shaped medium. Further, if the medium is stopped at a proper time, it can be used as a bulletin board for predetermined information.

[0110]

As is apparent from the above description, according to the invention of this application, since the predetermined saturated carboxylic acid and / or its derivative is used as the organic low molecular weight substance, the cloudy state to the transparent state or vice versa. It is possible to obtain a reversible thermosensitive recording material in which the temperature required for the change of is higher than before. Further, a reversible thermosensitive recording material is obtained in which the recording state does not change even when left in a hot atmosphere of at least room temperature to 80 ° C. Further, a reversible thermosensitive recording material having a higher contrast than the conventional one can be obtained. Therefore, it is a reversible heating recording medium (for example, a telephone card, an orange card, a highway card, etc.) that can be displayed by selectively heating it with a heating means such as a thermal head and can erase the display by applying a predetermined heat. It is possible to obtain a thermoreversible thermosensitive recording medium in which the recording state does not change even when the recording medium is left at a high temperature (for example, in a vehicle where the temperature inside the vehicle becomes 70 to 80 ° C.). Furthermore, such a thermoreversible thermosensitive recording medium can be applied to a thermoreversible thermosensitive recording apparatus that can be used at high temperatures (for example, mounted in a vehicle where the vehicle interior temperature becomes 70 to 80 ° C.).

[Brief description of drawings]

FIG. 1 is a diagram for explaining an example of a reversible thermosensitive recording material of the first invention, showing a change in transmittance of a layer made of this material with respect to a temperature change.

FIG. 2 is an explanatory diagram of a second embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 3 is an explanatory diagram of a third embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 4 is an explanatory view of the third embodiment of the reversible thermosensitive recording medium of the second invention, following FIG.

FIG. 5 is an explanatory diagram of a fourth embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 6 is an explanatory diagram of a fifth embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 7 is an explanatory diagram of a sixth embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 8 is an explanatory diagram of a seventh embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 9 is an explanatory diagram of an eighth embodiment of the reversible thermosensitive recording medium of the second invention.

10 is an explanatory diagram of an eighth embodiment of the reversible thermosensitive recording medium of the second invention, following FIG. 9. FIG.

11 is an explanatory view of an eighth embodiment of the reversible thermosensitive recording medium of the second invention, following FIG.

FIG. 12 is an explanatory diagram of a ninth embodiment of the reversible thermosensitive recording medium of the second invention.

FIG. 13 is an explanatory diagram of an example of recording information on the reversible thermosensitive recording medium and erasing information on the medium according to the second invention.

FIG. 14 is an explanatory diagram of a first reference example of a reversible thermosensitive recording apparatus.

FIG. 15 is an explanatory diagram of a second reference example of a reversible thermosensitive recording apparatus.

[Explanation of symbols]

21: support 23: reflective layer or light absorbing layer 25: layer of the reversible thermosensitive recording material of the first invention 27: reversible thermosensitive recording medium 29 of the second embodiment 29: protective layer 31: adhesive layer 33: printing layer 35 : Enhance layer 35a: Enhance layer composed of air layer 37: Recording layer (for code information) 39: Protective layer (second)
41: transparent support 51: support 51a composed of a plate-like body having an optical path changing function: end surface 61 of the plate-like body 61: frame 63: overall erasing tool 65: writing tool 67: local erasing tool 69 : Temperature controller

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeyuki Sekiya 1-7-12 Toranomon, Minato-ku, Tokyo Inside Oki Electric Industry Co., Ltd. (72) Yoshitaka Ishii 1-7-12 Toranomon, Minato-ku, Tokyo No. Oki Electric Industry Co., Ltd. (56) Reference JP-A-6-320860 (JP, A) JP-A-6-64318 (JP, A) JP-A-3-230993 (JP, A) JP-A-2 -1363 (JP, A) JP 5-193259 (JP, A) JP 55-154198 (JP, A) JP 6-48032 (JP, A) JP 3-2089 (JP, A) ) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41M 5/36

Claims (10)

(57) [Claims] 1. A reversible thermosensitive recording material containing a matrix material and an organic low molecular weight substance, the transparency of which changes depending on thermal history, wherein the organic low molecular weight substance is a saturated carboxylic acid group having a carbon number of 27 to 61 and derivatives thereof. A reversible thermosensitive recording material comprising at least 3 kinds of gentriacontanoic acid, nonacosanoic acid and tritriacontanoic acid as main components. 2. The reversible thermosensitive recording material according to claim 1, wherein the organic low molecular weight substance is, in addition to the three types, a monocarboxylic acid having 10 to 26 carbon atoms and a carbon number of 1
A reversible thermosensitive recording material containing one or more dicarboxylic acids having 0 to 26, monocarboxylic acid derivatives having 10 to 61 carbon atoms, and dicarboxylic acid derivatives having 10 to 61 carbon atoms. . 3. The reversible thermosensitive recording material according to claim 2, wherein the monocarboxylic acid derivative having 10 to 61 carbon atoms is selected from the group consisting of:
A reversible thermosensitive recording material characterized by being an amide, an amine, anilide, an alcohol, an ester, a ketone, a metal salt or an imidazole. 4. The reversible thermosensitive recording material according to claim 1, wherein polyvinyl acetal is used as the matrix material. 5. A layer composed of the reversible thermosensitive recording material according to claim 1 (reversible thermosensitive recording layer) and the reversible thermosensitive recording layer are supported directly or via an intermediate layer. A reversible thermosensitive recording medium, comprising: 6. The reversible thermosensitive recording medium according to claim 5, further comprising a protective layer on the side of the reversible thermosensitive recording layer opposite to the support, either directly or via an intermediate layer. A reversible thermosensitive recording medium, characterized in that at least one of the protective layer and the protective layer is made of a material having transparency to visible light. 7. The reversible thermosensitive recording medium according to claim 5, wherein when the intermediate layer is used, the intermediate layer is a reversible layer selected from at least a reflective layer, a light absorbing layer, an enhancement layer and a printing layer. A reversible thermosensitive recording medium, which comprises one or more layers selected according to the direction of light incident on the thermosensitive recording medium and the viewing direction of the recording formed on the medium. 8. The reversible thermosensitive recording medium according to claim 5, wherein the support is made of a material transparent to visible light, and the support is opposite to the reversible thermosensitive recording layer side. A reversible thermosensitive recording medium having a reflecting layer or a light absorbing layer on the surface side. 9. The reversible thermosensitive recording medium according to claim 5, wherein the support has a property of changing a traveling direction of light incident on the support. A reversible thermosensitive recording medium characterized by: 10. The reversible thermosensitive recording medium according to claim 5, further comprising a recording layer in addition to the reversible thermosensitive recording layer. Medium.